Hawach Scientific Co., Ltd

Hawach Scientific Co., Ltd

Hawach Scientific offers customer one-stop purchase, marketing strategy and solution for laboratory filtration products. We strive to offer the best solution for customers` business and superior quality products at a reasonable price. We are constantly focused on customers needs and do self-improvement to guarantee all customers needs can be satisfied. We love what we do and give our best enthusiasm and commitment to every customer we served. Put simply, if you want a partner who cares about your business choose Hawach Scientific.

Company details

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Business Type:
Manufacturer
Industry Type:
Laboratory Equipment
Market Focus:
Globally (various continents)
Year Founded:
2013
Employees:
11-100
Turnover:
less than $1,000,000 US

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Neutral Alumina is currently the second most popular packing material in flash chromatography. It is excellent for the purification of a compound with those properties is considered. The Neutral Alumina Flash Columns provides users a highly practical and efficient flash chromatography tool for organic compounds separation.

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Hawach Scientific Co., Ltd BIO-44 filter paper is a star product equivalent to Whatman’s Grade 44 with more competitive price, which has a high retention rate and slow flow rate (3μm). BIO 44 filter paper has lower ash than other filter papers in this series. The efficiency of collecting small particles is slightly lower than that of BIO 42, but the flow rate is faster.

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Hawach Scientific Co., Ltd electronic bottle-top dispensers can be with four plugs, which are USA plug, CN plug, Euro plug, UK plug. The range of the electronic bottle-top dispenser is 0.1-99.99ml. It can reduce the interference of human factors and make the whole process more accurate and reliable.

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QuEChERS ceramic homogenizers are mainly used for the QuEChERS sample preparation method. In the past methods, we usually needed to shake the vial for about 1 minute to obtain a sample without ceramic uniformity. During this time, sample recovery may be adversely affected. However, if you put the ceramic evenly, this will be true sample uniformity, This will help to reduce the inefficiency of the sample.

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The pipette stand has two series, linear and round stand for pipettes. Each stand can accommodate 6 single-channel pipettes or multi-channel pipette. The stand is light in weight, easy to organize and store. Also, it can be assembled conveniently. The non-slip and anti-shock pad is available on the bottom of the stand for pipette.

SAX SPE Cartridges

The strong anion exchange (SAX) solid phase extraction (SPE) cartridges are a quaternary ammonium bonded phase of the silica matrix, which is always positively charged in the full pH range and has a strong anion exchange capacity. Ion-exchange SAX SPE cartridges are ideal for extracting weakly acidic compounds such as carboxylic acids.

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The C18-Alkaline HPLC columns are a new generation of different selective C18 developed by Hawach. It has hydrophobic interaction and electrostatic interaction. It has a hydrophilic group embedded in it to make it hydrophilic. The hydrophilic group replaces a large amount of silicon. The alcohol-based site can effectively prevent the interaction between the alkaloid and the silanol group, and the alkaline substance has a good peak shape.

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With its filter media as hydrophilic PTFE, Hydrophilic membranes filters can help users reduce costs by eliminating the need for expensive pre-wetting in the applications that require the superior temperature, chemical resistance, and low extractors of PTFE membrane. Its bubble points (0.22μm, 0.45μm) are above or equals 0.1MPa and 0.06MPa respectively, with its diameter ranging from 13mm, 25mm, 47mm to 90mm, 142mm, 293mm. Its pore size are 0.22μm, 0.45μm and chemical compatibilities are superior to aqueous, organic solvents and mixed solvents. Hydrophilic PTFE membrane filters are the strongest membrane filters for strong acid, alcohol and so on. Our company has full range of products, diameters and pore size can be customized, OEM services are available as well.

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The 500mL glass solvent filters are made of super hard glass, and the collection bottle is 2000ml. The glass solvent filter has good pressure resistance and can be used in high temperature and high-pressure autoclave. Grinding standard, and dimensional specifications of the glass solvent filter is in line with international standards and can cooperate with many foreign brands. All our glass solvent filters are well suited to our vacuum pumps.

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Stainless steel 304 or 316L filter housing with titanium power sintered filter cartridges inside to use
Electro-polished filter housing, meet the GMP requirements
High-temperature resistant and wide chemical compatibility
The titanium filter cartridge can work under high temperature, can resist strong acid and alkaline conditions
Long surviving life
The filter could be backflushed and cleaned with chemical solvent, hot water, steam
Easy to install design, easy to clean
Available in tri-clamp connections

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Hawach cellulose extraction thimbles are made of high quality cellulose lint. High purity, high mechanical strength and strong retention. The thimble wall thickness ranges from 1 mm to 3 mm. Maximum operating temperature of 100 ° C, available in a variety of models and thicknesses, suitable for a variety of applications, designed to match most Soxhlet extractors.

Paper filter cartridges are commonly used in a variety of Soxhlet extraction, rapid solvent extraction or other similar extraction applications and are a safe, convenient and efficient extraction of solid and semi-solid materials.

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Features of Cellulose Acetate Syringe Filters

Sterile cellulose acetate syringe filter
Low protein binding
Superior strength and stability

Applications of Cellulose Acetate Syringe Filters

Protein and enzyme filtration
Cell culture
Clarification of aqueous and alcohol solutions
Hydrophilic syringe filters, suitable for aqueous solution treatment
Nitrate free, suitable for groundwater filtration
Biological sample preparation
Sterile filtration of low volume samples
HPLC samples containing low solid content –filtration will improve column life
Salt solutions
Buffer solutions

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Hawach Scientific Co., Ltd crimp caps provide excellent sealing, reducing the chance of sample evaporation. The cover is made of the aluminum cover and can be sealed with special tools to achieve a good sealing effect. Compared with the septa and cap for screw thread sample vials, it is more resistant to high temperatures in a high-temperature experimental environment and can adapt to harsh experimental conditions.

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Hawach’s name by Chinese means “the Cambrian”, also the Cambrian explosion. Here means we will keep on the way to become century enterprises and do better solutions for our clients, we also take responsibility for protecting reputation of the goods “made in China”
For customer, we do not only want to supply them goods but also be partners who offer stable service and long run customer value creation.

In the previous decade, we only focus on producing and OEM service to global market. The quality and production come better and better, mean time, we start to do some advertisement and expansion sales amount by our own brand for better image promotion.

Now, Hawach will keep all previous advantage and bring more solutions for our customers. The related industries will be at micro-porous filtration, industrial filtration, laboratory equipment, medical equipment and instruments, the chromatography consumables and purification, life science, biological solutions etc.

Please be free to contact us at info@hawach.com for any new inquiry or cooperation purpose.

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Advantages:
1 Such a washing procedure does indeed make it possible to wash the 2m vials (sample vials). After washing, the bottles actually look much cleaner than before. The Shimadzu HPLC, GC and Agilent HPLC-MS The peaks in the previous solution were also not seen in the /MS instrument.

2 It does indeed save a lot of wasting time. I used to wash 300 injection bottles for a day. I now have 400 injection bottles for 1.5 hours. According to the inventor’s design process, organic solvents and water consumption are also A lot of savings, I remember the cardboard instructions that the total consumption of three organic solvents is not more than 2L, the total consumption of pure water is not more than 25L, the consumption should be about a few, but it should be about the same.

Disadvantages:
1 The washing procedure designed by the instruction manual is too ideal. It is very difficult for the laboratory to accumulate 400 sampling bottles before washing. Unless the Ministry of Agriculture laboratories for certification of pesticide residues like us do, sometimes more than 200 injections are needed per day. Bottle, my other classmates spent more than 100 a week was good.

2 The inventor’s step-by-step washing design considers that there is nothing wrong with saving solvents and saving time, but he needs to know that the lab’s washing habits are very different. For example, we The organic washing solvent in the laboratory is used to recover organic solvents that are reused. These solvents are directly discharged into the waste container. It is indispensable to use more or less at a time, and there are many laboratories for my classmates. It is better to wash it with water and soap twice or three times, and rinse it with water for seven or eight times, not to mention saving any solvents. I think that I put 200 together (2 bottles of washing bottles) into a big box, and the large box is placed in ultrasonics and washed with ultrasound, so the time of ultrasound can be set at random. When I was washing with organic solvents for the second time, I switched to another big box. In doing so, I purchased half of the products, that is, two large boxes and two small boxes, which saved general purchase costs.

Advantages and Disadvantages of the Use of 2ml Chromatography Sample Bottle Quick Washing Box

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Hawach Scientific membrane filters are a thin, polymeric film made up of millions of microscopic pores. Membrane retains particles and microorganisms that exceed their pore ratings by acting as a physical barrier and capturing such particles on the surface of the membrane. It is simple and fast to use, and is widely used in many fields such as scientific research, food testing, chemical industry, nanotechnology, energy and environmental protection.

The form and shape of the membrane filters are highly dependent on the manufacturing process and are often difficult to specify. We Hawach Scientific is available to supply membrane filer in roll or disc type. And what’s more, there’s a full size range of membrane media including Nylon, PTFE, PES, PVDF, MCE, CA, GF, PP.
Other key parameters are pore size and diameter. The range is very wide listed as below:

Pore size: 0.1um, 0.22um, 0.45um, 0.8um, 1.0um, 3.0um, 5.0um, 10.0um

Diameter: 13mm, 25mm, 47mm, 50mm, 60mm, 90mm, 142mm, 150mm, 200mm, 293mm, 300mm

Applications: Aqueous filtration(Nylon, PTFE-L, PES, MCE, CA)
Colony counting(MCE Gridded Membrane Filter)
Microbiological and particulate analysis
General biological filtration,
Filtration of samples for high protein recovery
Pharmaceutical
Environmental
Agricultural industries.

A wide range of membrane filter products are available to match your needs, we accept OEM products and customized size, if any questions, please don’t hesitate to contact me.

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Characteristics of stainless steel filter cartridge:
1. Good filtering performance and filter granularity for 2-200um can play a homogeneous surface filtration performance.
2. Corrosion resistance, heat resistance, pressure resistance, good wear resistance, uniform and accurate filtration precision of
3. Stainless steel filter cartridge is suitable for low temperature and high-temperature environment. After cleaning, it can be used again without replacement.

Application: petrochemical, oil field filtration, construction machinery and equipment fuel filtration; water treatment industry equipment filtration

Feature:
Excellent chemical compatibility, suitable for filtering strong acid, strong alkali, and an organic solvent; filter membrane is foldable deep layer filtration, large area of membrane filtration, low-pressure difference, strong capacity, long service life, and wide filtration accuracy.

Application field as below:
Pharmaceutical industry: pre-filtration of various antibiotics, such as antibiotics
Food and beverage industry: wine, mineral water, and drinking water filtering oil Industry: oil field water injection filtration electronics industry: high pure water prefilter
Chemical industry: filtration of various organic solvents.

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Simply put, the headspace analysis is to analyze the gas present in the headspace vial. The laboratory vials used for headspace analysis are called headspace vials.
The essence of this experiment is that the volatile sample is heated and volatilized to form a gas in the space on the top of the sample vials and then diffused. Eventually allowing the top gas in the gas chromatograph vials above the volatile sample to enter the gas phase detection.
Adaptation: top gas chromatography
When the volatile or semi-volatile mixture has a higher boiling point, we need to heat it up to get it vaporized at the top. In this process, the liquid (solid or solid-liquid coexistence) sample is at the bottom, so the substance in the top gas can eventually be measured without touching the liquid in the sample bottle.
Top space gas chromatography is most suitable for the sample analysis of light component volatiles. This measurement technique can be used to analyze the gas in the top space of the liquid sample and apply to the solid dispersion method.
Top space gas analysis also helps in automated quality control or sample screening. This is a highly reproducible sample using modern instruments, enabling the entire experiment to be prepared for analysis in an efficient and accurate manner.
Application:
GC headspace technique is used to analyze the gasification of solid and liquid samples of volatile organic compounds. In recent years, the popularity of this technology has been recognized by laboratories around the world, especially for the analysis of residual organic solvents in alcohol, blood and pharmaceutical products.
Other common applications include industrial analysis, detection of volatile substances such as chemicals and plastics, flavor compounds in beverages and foods, perfumes and cosmetics.

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Syringe filter could be mainly divided into two types which are hydrophobic and hydrophilic respectively. It is a good way to encode according to the colour of the filter shell so that filter material could be easily recognised and the unnecessary laboratory mistakes could be avoided. Nylon thin membrane is the cheapest and most harshness-tolerant chemical for the normal filtration. The other popular material is PTFE that is also segmented into two types- hydrophobicity and hydrophile. There are some normal filter materials, such as PTFE Hydrophobic membrane, Hydrophilic PTFE membrane, PES Hydrophilic membrane, CA Hydrophilic membrane, PVDF Hydrophobic membrane, Hydrophilic MCE membrane, Glass microfiber Hydrophilic materials and so on.

When choosing the filter material, some instructions should be followed. First of all, the sample you are filtering should be compatible with the filter material. Then, it should be consistent with the filtration test. Then, the selection of filtration material should be conformed with S.O.P. of the proceeding test. Finally, the material could use the minimum pressure to filter most of the samples.

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Hawach filter paper is used for removing contaminated particles from liquids and gases. The design of a filter paper must try its best to strike a balance among various indexes so as to effectively protect the system to be filtered.

Production of a filter paper
It is that a variety of fibers are soaked in the water-based adhesive and completely disperse, and then form a tightly bonded paper roll on the screen, through drying, dipping, and then trying to achieve an acceptable level of humidity.

In general, the filter paper used for diesel has higher precision and smaller apparent gravity. The application of glass fiber reduces the apparent specific gravity of the filter paper. Therefore, its carrying capacity is greatly improved under the condition of maintaining the same filtering precision as the whole wood fiber filter paper.

Filtering mechanism of a filter paper
1. Direct capture or interception;
2. Adsorption;
3. Impact and immersion;
4. Filter agglomerate.

The development of a filter paper
With the continuous improvement of papermaking technology, there will be more and better filter papers, whose application will be more and more widely.

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1. When installing the intake tube and the drain tube, insert the bottle-top dispenser tubes straight into the valves, tighten the nut properly to protect the tubes.

2. Make sure bottle-top dispenser that the intake and drain valves and all valves are properly installed and tightened to prevent splashing of the piston movement before using the equipment.

3. When draining, make sure that the drain tube is not directed towards the operator to avoid danger.

4. When draining, control the piston to move at a constant speed and use a suitable container to receive the liquid and let the liquid run down the side.

5. If you encounter any trouble during draining, please don’t continue the operation in any violent way to avoid further damage to the equipment.

6. After using the bottle-top dispenser, please fasten the safety cap of the drain tube to prevent the liquid in the drain nozzle from dripping due to gravity or water vapor in the air.

7. After using the instrument, please rotate the adjustment ring to “0” position to ensure safety.

8. Restricted reagents: HF acid and bromine suspensions. (A special bottle dispenser is required when using such restricted reagents.)

9. Do not apply organic reagents to the surface of the equipment. If the accident happens, wash the equipment surface in time with water.

10. The bottle-top dispenser is suitable for operation at a temperature of 33.8-122°F or 4-50 °C.

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The installation method of the extraction thimble is divided into vertical lifting, oblique mounting at a specific angle, flange mounting, and the like.

The automatic cleaning method commonly used in the extraction thimble is high-pressure gas pulse back-blowing and mechanical vibration. The pulse backflushing is a signal given to the solenoid valve by the parameters preset by the controller, and the diaphragm of the solenoid valve is instantly opened and closed, so that the high-pressure gas enters the blowing pipe, and the dust of the surface of the filter cartridge is shaken off by the rapid expansion force of the gas, and the gas pressure is generally We set it to about 6 kg. Mechanical vibration cleaning is often used in small single-unit extraction thimble dust collectors. It uses the shaking force generated by the eccentric device on the dust collector’s flower plate to clean the dust. This action requires operation after shutdown.

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The QuEChERS method was originally designed to extract pesticides from fruits and vegetables. The combination of salting out and d-SPEpurification in the initial liquid-liquid extraction also showed satisfactory results in the multi-residue analysis of pesticides, veterinary drugs, and mycotoxins in various foods and agricultural products. Hawach QuEChERS solution offers many advantages over other pesticide analysis products and technologies:

1. Easy and straightforward, almost no training is required
2. Reduced overall sample preparation time
3. Products from the same supplier, better consistency and reliability
4. Efficient, economical, suitable for analysis of multiple commodities
5. Better consistency of extracted targets
6. Improve laboratory efficiency and improve laboratory workflow
7. Improve the stability of the results

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Introduction of Hawach scientific glass solvent filters

Hawach scientific glass solvent filters with high-quality glass material, uniform wall thickness, no bubbles, beautiful appearance, can be used for sterilization under high temperature and pressure, good sealing performance, fast flow, standard grinding mouth. The device is lined with a microporous membrane, which can be used for chemical analysis, health inspection, biological pharmaceutical and pesticide, petroleum, environmental protection testing and other aspects of sample filtration. To detect and remove particles and bacteria from the liquid. More detail information from info@hawach.com
Structure

This device is made of high-quality glass, It is divided into three parts: upper, middle and lower parts. The upper part is a cup type grinding port container named filter cup. The capacity is divided into 300ml and 500ml, in the middle is an internal grinding mouth support device with a suction nozzle.

There is a flat glass sand chip in the center for supporting the filter membrane, called the filter head, corresponding specifications are 1L and 2L. The lower end is a pressure vessel with an external grinding mouth, which is called a triangular bottle; The corresponding capacities are 1000ml and 2000ml and equipped with aluminum alloy special clamps for the whole device with a tight connection, clamps through an oxidation treatment, chemical corrosion resistance.

Product Code: SLGSF03001
300ml Glass Solvent Filters
– 300ml glass funnel.
– 1000ml glass collection bottle.
– Anodized aluminum spring clamp.
– Support frit and base. The whole set can be autoclaved at 121° C

Product Code : SLGSF05002
500ml Glass Solvent Filters
– 500ml glass funnel.
– 2000ml glass collection bottle.
– Anodized aluminum spring clamp.
– Support frit and base. The whole set can be autoclaved at 121° C

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Hawach pipette tips are in accordance with EN ISO 8655 international standards. Make sure the tip and the pipette are tightly sealed to reduce the force used to load and unload the tip. The ideal wettability, high transparency and specific, proven cleanliness levels intuitively interpret our products and production concepts.

Features:
1. Optimized nozzle shape design, perfect for Hawach pipettes
2. Hawach pipette tips are versatile and can be adapted to other brands of pipettes
3. Fine-scale for easy and intuitive observation of pipetting volume
4. The slim tip can reach the narrow, deep container bottom without touching the top edge of the container
5. The tapered tip can easily handle a small amount of liquid
6. High quality original pipetting tips, self-sealing bag packaging
7. Clean grade, measuring range 10 μL – 10 mL
8. The tip can be autoclaved at 121 °C

Applications:
1. Removal of liquid
2. Liquid dispensing
3. liquid mixing
4. Working plate and reaction container loading
5. Gel electrophoresis loading
6. Remove supernatant after extraction

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Solid-phase extraction (SPE) is a useful method of sample preparation. By sorting onto a disposable solid-phase cartridge, it can concentrate and purify analytes from solution. But sometimes, the results are unsatisfied with the poor and non-repeatable sample recovery. To avoid it, we’d better find out the reason.

First, wrong sorbent bed. According to the working principle of SPE, we must choose the sorbent bed fully retained with the analyte of interest. Poor recoveries will be found when the sample is leaching during load and wash.

Second, wrong wash solvent. The past experience has fully proved that, only if the wash solvent is strong enough, the most interference can be removed without eluting any sample.

Third, wrong elution solvent. We must make sure that the eluting solvent we choose is strong enough to elute 100% of the sample, as while as weak enough to leave more interfering contaminants on the SPE column.

Perfect balance of the three parameters: the sorbent, the wash solvent, and the elution solvent, will help us achieve the best sample recovery from solution.

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Anion HPLC columns characteristics

(1)The Anion HPLC columns are high capacity, high efficiency, hydrophobic anion exchange column. Used to separate a wide range of valence anions, including polyphosphates, polyphosphates, and other multivalent complex reagents such as EDTA and NTA.
(2)Use polyphosphates, and chelating agents in complex sample matrices.
(3)Sulfide was determined using sodium hydroxide and wastewater samples for amperometric detection.
(4)Analysis of the use of hexavalent chromium columns after the reaction and environmental media absorption of visible light detection, including wastewater chromium, drinking water, and air.
(5)Separate inorganic and organic species of arsenic and urine samples in drinking water.
(6)High capacity, higher resolution.
(7)Longer retention times are required, but the resolution is higher.
(8)Promote rapid analysis of organic acids and anions in well-characterized samples.
(9)Particularly suitable for separating complex sample matrices or uncharacterized organic acids and anions in samples.
(10)Recommended for monovalent and divalent organic acids.

Anion HPLC columns operation precautions

(1) The column must be connected to the chromatograph after the column’s flow line is completely filled with the eluent.
(2) Connect the column to the direction of the flow path identified on the column.
(3) An appropriate amount of organic solvent may be added to the eluent for modification (less than 50% acetonitrile or methanol, etc.).
(4) The recommended temperature is 35C. It is recommended to use a column oven. The temperature has a certain correlation with the elution time of each ion. When the temperature changes, the elution time of the ions changes.
(5) After the pump is turned on, keep the flow rate below 0.5mLUmin, and then gradually increase the flow rate to the working flow.
(6) For samples containing organic matter and impurities, please pre-process the sample before injecting the sample.

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Filter membranes have different types and apertures for removing bacteria and impurities, which is important to protect the chromatographic system and column.

Factors to be considered in the selection of membranes

The first thing to consider is chemical compatibility, that is, whether the filtration membrane is acid, alkali, organic solvents and so on.
1. The apertures of the filter membrane;
2. Characteristics of the filter sample.

Characteristics and applications of several common filter membranes:

1. Water system filter membrane
Uniform pore size, high porosity, no media shedding, thin texture, low resistance, fast filtration speed, low cost, but not resistant to organic solutions and strong acids and bases.

2. Nylon filter membrane
Good temperature resistance, high-pressure sterilization of saturated steam for 30 minutes, the highest working temperature 60 ℃, good chemical stability, can withstand dilute acid, dilute alkali and other organic and inorganic compounds and solvents.

3. PVDF filter membrane
High mechanical strength, good tensile strength, good heat resistance and chemical stability, low protein adsorption, strong hydrophobicity.

4. PTFE filter membrane
Wide chemical compatibility, good temperature resistance, strong acid, and alkali resistance, suitable for strong chemical corrosive solvents and oxidants.

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Hawach Scientific PP filter capsule adopts laminated membrane, large surface area, suitable for a larger volume of solution filtration, sealed by a special process, free of adhesives and other chemicals. The shell and support materials are made of high-quality polypropylene, and the filter medium is polypropylene film. The polypropylene structure has stable performance and wide chemical compatibility.

High filtration efficiency and purity. It is widely used for filtering various solvents under different PH and temperature conditions.

1. Steam or ETO can be used for pressure heating disinfection
2. Hydrophobic polypropylene film and polypropylene shell are corrosion resistant
3. The durable low-pressure difference, high flow, long service life
4. Wide applicability

Application

1. Pharmaceutical industry: filtration of pharmaceutical liquids, cell fragments, biological products, etc
2. Chemical industry: filter organic solvent, chemical reagent, ink, electroplating solution, etc
3. Food industry: drinking water, mineral water, beverages, beer, wine, wine, and other filtration
4. Electronic industry: prefiltration of the reverse osmosis water system and prefiltration of the deionized water system
5. Gas filtration: compressed air, nitrogen, carbon dioxide, etc
6. Other industries: photosensitive resist, magnetic media, and other filtration

Specification data

Diameter: 3.2inch/82.4mm
Length: 81.5inch/207mm
In/out: Φ1inch/25.4mm
Filtration area: ≥ 2.2tf²/0.2m²
Maximum service temperature: 80℃
Positive pressure difference: liquid: 3.5bar@23℃,3.0bar@60℃; gas : 3.0bar@23℃,2.5bar@60℃
Sterilize: can be affected by three consecutive 121 ℃ high-pressure steam sterilization, sterilization online is not recommended

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Flash Columns Series

Flash Columns produced by Hawachhas three series as follows.
StarFlash
Only silica gel columns are optional with another two types of standard and high-grade level which has higher purity degree and better quality than the former.
PureFlash
Corresponding to silica gel bonds and phase columns, there are C18(Both spherical imports and irregular domestic involved), C8, NH2, CN, HILIC and alumina, which are all exotic fillers to supply to the high-end market.
DepuFlash
C18, C8, NH2, CN, Phenyl, SAX, SCX and Doil, which are all domestic fillers for the low-end market.
Essential Technical Parameters
Material
Medical PP tubular column, medical sintered PE sieve plate and imported absorbent packing.
Parameters of Stationary Phase
matrix type (e.g. silica gelor polymer)
bonded phase type (e.g. C18 or CN)
particle size (e.g. 3or 5 um)
surface area of stationary phase(e.g. 130 m2/g)
bore diameter
homogeneity
purity of stationary phase
Specification
Packing(g): from 4mg to 33g (Different series contains distinguish maximal weights)
Flow velocity: from 10 to 100ml/min
Maximum operating pressure
Others(length * diameter)

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sample vials cap (or gasket), made of paper, rubber, corkwood, metal, glass fiber or plastic polymer, is placed between the two planes to strengthen the seal and prevent fluid leakage. Machined surfaces cannot be perfect so use caps to fill in irregularities. Asbestos may be present in caps for specific applications.

The function of the sample vials cap

1. Prevent damage to objects caused by the use of spring pads in the process of removing screws.
2. Increase the contact area.
3. It can be used in some special situations.
4. Increase friction.

The choice of sample vials caps material mainly depends on the following three factors: temperature, pressure, and media. According to its material and structural characteristics, caps can be divided into non-metallic caps, metallic caps, metal-non-metallic composite caps, each category of which also can be subdivided into a number of types.

Sealing sample vials cap installation requirements

1. The sealing surface shall be cleaned.
2. When the sealing cap is pressed, it is best to use a torque wrench.
3. When installing the sealing caps, tighten nuts in sequence.
4. The pre-tightening force of the sealing cap shall not exceed the design specification.

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High performance liquid chromatography (HPLC) is an analysis method originated from classical liquid chromatography. It is fast and accurate, but the device is precise and expensive. Under this condition, it is particularly important to extend its service life by optimizing the operating processing and maintenance carefully Here the Hawach recommends some membrane filtration methods for the protection of the components of the HPLC system.

Membrane filtration of mobile phase

As the carrier of the substances to be tested, the mobile phase will pass through the degasser, high-pressure infusion pump, sampler, chromatographic column and finally enter the detector. The purity of the mobile phase will affect the service life of related components directly. If it is not filtered, the particles which it contains will enter the system to consequent blockage.
Hawach advises filtering the mobile phase with 0.45 nm or 0.22 um pore size membranes or Φ 33 mm FILSTAR Syringe Filters before using. Besides particles, membrane filtration can also remove small bubbles from mobile phase, reduces the burden of degasser to the stabilize the analysis process.

Membrane filtration of samples

There are many quite different kinds of samples can be determined by HPLC. If the samples injection happens directly without filtering, the chromatographic column will be blocked in a short time. That will make column pressure increase and sharply reduce its service life rapidly.

Therefore, Hawach advises to pre-filter samples with syringe filter adapting 0.45 um or 0.22 um pore size filter membranes. Generally, the volume of the samples as the basis to select the model and specification of syringe filters. For the samples that are difficult to filter with larger particle load, the syringe filter containing glass fiber or PP pre-filter layer can be selected.

The service life of HPLC can be extended effectively by the filtration of the mobile phase and samples according to the above suggestions.

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General Categories of Filter Papers
All the Filter Papers of Hawach Scientific Co., Ltd are made of cotton fiber, which can also be divided into qualitative filter papers and quantitative filter papers. The former can be confirmed its compositions and possesses a standard level and a wet strong level. Similarly, the later one telling how many bits of substances in the transportation is distributed into other three sub-levels, which is decided by the ash amount. To express this in a specific way, there are ashless, Hardened low ash and hardened ashless grades.

Technical Parameters of Filter Papers

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The bottle-top dispenser is a device which installs into a large amount of solution at the mouth of the solvent bottle.

Hawach Mechanical bottle-top dispensers have 4 ranges, 0.5-5ml, 1-10ml, 2.5-25ml, 5-50ml can meet all your measuring accuracy.HawachElectronic bottle-top dispensers can apply to all countries around the world with 4 plug options, USA, CN, EURO, and the UK, get tired of too many times measurings and high-frequency operations, pick our electronic ones to Liberate the workforce.

How to choose your suitable dispenser?

8 material choices: optical glass, Al2O3, ETFE, PFA, FEP, PTFE, platinum-iridium alloy and PP (hard hat). The similar way as choosing filter paper according to their chemical properties.

Considering chemical resistance and chemical corrosion, don’t try sodium azide, hydrofluoric acid (HF), H2O2, Nicotinic acid, trifluoroacetic acid, tetrahydrofuran, carbon disulfide, carbonaceous solution, concentrated hydrochloric acid, nitric acid, chlorinated hydrocarbons , fluorinated hydrocarbons and liquids which can cause the piston sticking or cause blockage through forming precipitates (such as crystallization solution or concentrated alkaline solution).

Our High-performance bottle-top dispenser with excellent chemical resistance, advanced functions, the wide range of dispensing needs and customized ability are always here for you!

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Economic Impact Analysis

From the current US market price analysis, it’s easy to find out that the quartz fiber extraction thimbles are priced much higher than the common extraction thimbles. The high-purity quartz fiber extraction thimbles are manufactured from pure quartz and are harder to find.

A Substitute for Quartz Fiber Extraction Thimble in Environmental Monitoring

In the monitoring of the amount of heavy metal in the exhaust gas during the environmental monitoring, the ordinary glass fiber extraction thimbles are treated in different ways in order to reduce the influence of its lead content on the monitoring results.

In the daily environmental monitoring, the monitoring of the lead content in the exhaust gas discharged from extraction thimbles treated by the unified immersion method has given the stably satisfactory results. The use of unified immersion method to treat ordinary glass fiber extraction thimbles can achieve comparable results to quartz fiber extraction thimbles, which can significantly reduce the cost.

With such finding, the extraction thimble users can use the glass fiber extraction thimbles to replace the quartz fiber extraction thimble as long as they proceed the suggested treatment.

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The definition of QuEChERS and Product Information

QuEChERS means Quick, Easy, Cheap, Effective, Rugged and Safe, which is a sample preparation method and applied for the detection of Agricultural Products widely. Hawach has a great diversity of QuEChERS products for your choice, including the Extraction kit, the Extraction salt, Dispersive SPE Kit, Dispersive Absorbent, Ceramic Homogenizers.

Workflow

Firstly, you should select the test method, such as AOAC or EN, and prepare the buffered Extraction Kit & 50ml tube. Put the 10g or 15g comminuted sample into the tube and add the acetonitrile & extraction salt. After shaking the tube with 1 min, add the internal standard into the tube and do the centrifuge. Extracting the supernatant solution of 1ml, 6ml or 8ml and transferring it into dispersive SPE kit. In the same way, after shaking the tube with 1min, to do the centrifuge and Aliquoting the supernatant solution. Take it to be ready for analysis with GC-MS or LS-MS. Finally, achieve the analysis report. The whole of the process just takes about 30 minutes, which is a very convenient and fast operation.

If you are interested in Hawach QuEChERS products, welcome to have the request of quotation. The E-mail available: info@hawach.com.

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The laboratory vacuum pump is a basic instrument that can be used with a variety of instruments and equipment. It is very versatile. With the continuous upgrading of laboratory equipment, the requirements for vacuum pumps as auxiliary instruments are also increasing.

Standard diaphragm vacuum pumps is an oil-free vacuum pump designed based on the user’s new requirements. It solves the problem that traditional pumps need to be filled with water. The pump needs to be added and replaced, and there is pollution.

The standard diaphragm vacuum pumps use an oil-free piston structure. It does not require the addition of pump oil or water. It only needs to be plugged in to start the work.

The two-stage series pumping structure design can make it shorter. High vacuum is achieved in the time; the low-noise air-cooling heat dissipation system is installed on the side of the secondary cylinder, which greatly reduces the heat during the working of the machine, ensuring that the model can work continuously for 24 hours for a long time; Working noise, the air outlet is equipped with a silencer to reduce wind noise.

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Pipettes are precise instruments for removing small amounts of liquid. Various pipettes are indispensable tools for quantitative addition of various liquids in chemical technology, pharmaceutical research, biological analysis, environmental experiment, food detection, clinical diagnosis, biochemical determination, immune experiment, and micro-component analysis. According to the different working mode, the pipette can be divided into two types: mechanical pipette and electronic pipette.

Electronic pipettes

The electronic pipette is less used in all kinds of experimental analysis and measurement applications relatively. The electronic pipette is divided into four products according to the plug: USA plug, Cn plug, Euro plug, and a UK plug.

Mechanical pipettes

The standard series pipette are half autoclave sterilized at 121℃. The standard series has been refined to include four products: single-channel Adjustable volume, single-channel fixed volume, eight-channel Adjustable volume, twelve-channel Adjustable volume.

The advanced series are also half autoclave sterilized at 121℃. Unlike advanced series and standard series, the advanced plus is sterilized are fully autoclave at 121℃. So the plus series is more used for biological laboratory analysis. The standard and advanced plus series are also exactly the same subdivided into four products like the first two series.

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Solid-phase extraction is the simple method with digital chromatography compounding either bind or flow through. With solid-phase extraction, many samples can be analyzed almost automated in parallel, but the process may take more time.

Due to its high selectivity, recovery, and reproducibility, SPE methods are widely used for desalting, solvent exchange, sample preservation, and storage.

Compared with the liquid-liquid extraction, the advantages of solid-phase extraction is easy to see. It improves throughput in parallel vs. serial processing, as while as decreases organic solvent usage and waste. It achieves higher and more repeatable recoveries, cleaner extracts from contamination and solvent impurities. The choices of SPE phase and solvent mixtures are always various.

Common applications of solid-phase extraction can be sample cleanup, such as in pharmacokinetic studies, dissolution testing, isolate analytes from complex matrices, such as urine, plasma. It works perfectly but only removing major interferences, but also eliminating late-eluters for the isocratic analysis.

SPE is a reliable method to enrich trace in the environmental analysis, the pharmaceutical and agrochemical applications. It is also practiced widely in processes of desalting, solvent exchange and sample preserve.

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HPLC columns are manufactured and tested to exacting standards. If you use and maintain a liquid chromatography column with the following information, you will not only get better results but also extend the life of your HPLC column.

Installation of HPLC columns:
1. First, check that the column and instrument connections and piping are matched. In order to reduce the dead volume, the inner diameter of the connecting pipe between the injection valve, the column, and the detector should be as small as possible, and the length of the connecting line between the injector, the HPLC column, and the detector should be controlled. Before installing the LC column, verify that the solvent in the flow path system is normal. It is recommended to install a guard column for more complex samples.

2. In order to achieve the best connection between the HPLC column and the instrument system, the nut and tapered joint matching the LC column interface should be used as much as possible. For example, the original joint is long-term matched with other types of LC columns. Check the match before connecting the new HPLC columns to avoid damage to the HPLC column or leakage due to the mismatch in the HPLC column.

3. the use of PEEK material universal joints, only need to hand tighten without the need for a specific wrench, the use of pressure is 5000psi; the use temperature must not exceed 100 °C.

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The microporous membrane is one of the most widely used membrane types in membrane separation technology. It has the characteristics of large gas flux, high particle retention rate, good temperature resistance, strong acid, strong alkali, organic solvent and oxidant, anti-aging and non-stick, non-flammable and non-toxic, and good biocompatibility. Its material can be divided into organic and inorganic categories.

In view of the separation characteristics of the microporous filter membrane, the application scope of the microporous filter membrane is mainly to trap particles, bacteria and other pollutants in the gas phase and liquid phase to achieve the purpose of purification, separation, and concentration.

For microfiltration, the membrane interception characteristics are characterized by the pore size, usually ranging from 0.1 microns to 1 micron, It can be used for clarification, security filtration and air sterilization of general liquid. It is widely used in scientific research, medicine and health, biochemistry, food, energy, microelectronics industry, nanotechnology, environmental protection, and other departments.

Microporous membrane application

This product is mainly used for the filtration of the mobile phase and sample in chromatographic analysis. It has a good effect on protecting the chromatographic column, infusion pump pipe system and injection valve from contamination.

Microporous membrane material

1. MCE gridded membrane filter
2. Nylon membrane filter
3. PTFE membrane filter
4. PES membrane filter
5. CA membrane filter
6. PVDF membrane filter
7. GF membrane filter
8. PP membrane filter

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The structure of capsule filtration components is compact, which is quite convenient to use. More than that, its design could meet the highest standard of reliability, security and user convenience.

In order to satisfy numerous needs, it combines all other kinds of the filtration medium, pore size rating, and superficial area. Every capsule filter is made of compact and folded filtration components, which is sealed in a solid and disposal Polyacrylic cover.

According to the unique and advanced craft, filtration components and the cover are thermally bonded into an independent unit. It is the permanently sealed integrity structure which provides the most powerful guarantee for the filtration capability, reliability and security in the widespread fluid and applications.

Capsule filter should provide various size and different kinds of adaptors so that it could easily and quickly connect to the most filtration system.

Capsule filter could satisfy key requirements to contamination in many fields, such as pharmacy, biology, biological processing, electron, chemical industry, beverage, cosmetics and so on. In addition, it is used for controlling the particles and microbial pollution in liquid and gas, which provides reliability and convenience in testing.

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Flash columns can be used by a new chromatographic system that is flash chromatography or flash purification. It is mainly used for the separation and purification of a large number of complex organic compounds, combinatorial chemistry, new drug development or natural product research process.
The system is characterized by high efficiency and automation. Positive or negative flash columns at low pressure can separate most of the samples in 30 minutes.

Separation principle of flash columns

It can be approximated as a simple chromatographic process that uses the liquid as the mobile phase.
Flash columns are used for sample pretreatment and extraction/concentration of the target substance in the sample.
Matters needing the attention of flash columns.

1. All joints in the liquid chromatography may leak. Mind the toxicity and flammability of the mobile phase.
2. Opening the column may reduce the pressure limit.
3. If the chromatographic column is opened, operate in a well-ventilated environment.

Maintenance of flash columns

Samples containing particulate matter may block the filter element at the sampling end of the flash column, so the sample should be filtered before sampling.

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General-usage of sample vials is for collection, storage, and transportation. Based on content and process requirements, Users may choose the right vials in options of different materials and capacity.

Hawach glass vials are available in amber or clear transparencies for effortless viewing and easy specimen retrieval. Different kinds of tops: Screw thread top, crimp top, and snap top secure your content and ensure its integrity.

Borosilicate glass is formed with constituents of silica and boron trioxide. It’s well known for having low coefficients of thermal expansion, making them more resistant to thermal shock than common glass.

To protect against change, we have glass vials available in low extractable borosilicate glass, which is suited for lab research when the stability of the glass is in the first place. And our autoclavable sample vials designed for maximum recovery will eliminate liquid sample waste.

Our selection of sample glass vials provides storage for all types of samples in various vial types, colors, sizes, cap liners, and caps to meet your personal application. And you will find that all of our glass vials are well fitted for autosamplers.

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What should we consider when it comes to purchasing syringe filters of high cleanliness?

When we talk about syringe filter cleanliness, we should consider particle contamination from filter, filter hardware, filter installation and the using process as each source may increase the particle load of the product and affect product quality. In addition to the particle concern, liquid filters may involve sources of other contamination, such as endotoxin, organic carbon or oxides. Possible sources include surfactants, wetting agents, additives in the production of plastic components, residue from the manufacturing process and structural materials.

How can the cleanliness of a filter be monitored and controlled?

Through the inspection of the filtrate, the syringe filters manufacturing process can be well monitored, which is what we strictly perform for each batch of filters. The user of the filter needs to consider such an inspection test when they make their initial filter purchase, which can be a basis for evaluating the quality of the filter. Besides, pre-flushing syringe filters in daily operations can reduce the level of particles and pollutants and can be done as part of the vetting process prior to integrity testing.

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The conventional membrane filter device comprises a vacuum manifolds filtration system, joint flask, and the vacuum source. Conspicuously, the essential part is the filtration system, which consists of three glass filter holders with respective values and two handles placed on both sides.

Specific Operations
1. Loosen the bottom nut and lift the fixed mount, then place a rubber ring under the porous plate and a membrane gasket on that plate. Next, put the microporous filter membrane on it and place the filter gasket, then install the glass tube and a sealed sheet rubber on the top of the tube. Mount the fixator, tighten the bottom nut, and the cover the top lid.
2. Remove the top sheet rubber for the unsealed environment.
3. Connect the bottom drainage pipe with a rubber pipe, and wrap the orifice with gauze.
4. Warp up the whole filter and its base together then sterilize them at 121℃.

Precautions
1. Slightly loosen the filter cover or pierce a syringe filter before steam sterilization and connect to the air filter for ventilation.
2. Immerse the membrane into sterile water for 4- 6 hours before sterilization, then pour the water and operate the same way as above overnight.
 
January 9th, 2019

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Here we talk about the following four kinds of common filter papers about their constitution and characteristic that we can distinguish them.

The first one is PP filter paper. PP filter paper is made from polypropylene as the raw material through a proprietary hot melt process, which generates a new type of filter material. There are many advantages of this filter paper. It is anti-acid and anti-alkali, which helps its corrosion preventive characteristics. And it’s also poison-free and odor-free, low-resistance but high-efficiency. How could we identify this kind of filter paper? Although it is easy for us to tear by our hands, it still has a certain strength. Its color is an off-white color.

The second is PET filter paper, which is made from several materials including polyester resins. This filter paper is better in hardness、stiffness and stability. It has corrosion resistance and thermostability. As to this filter paper, it’s too hard for us to tear open.

The third is compound filter paper. What is the compound filter paper? It is that we put PP high-efficiency membranes onto the PET materials through the hot-melt adhesive or some other methods. We can identify it directly. This filter paper consists of two layers of different materials. One is PET as backing material, the other is PP, which is soft. And the compound filter paper is hard to tear because it has the characteristic of hardness and stiffness from PET.

The last one is high-performance glass fiber filter paper. It is often used for the nuclear industry in the past. Although it has excellent performance infiltration, it is difficult to handle and deal with. We can tear it quite easily. However, we couldn’t see it usually in daily life.

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Hawach has two types of the bottle-top dispenser, the electronic one and the mechanical one. They are made of excellent chemical resistance and the components are made of PTFE, FEP, BSG, PP. It is available for fully autoclavable at 121℃.

The electronic bottle-top dispensers, the volume range is from 0.1ml to 99.9ml. The max piston lift is 10 ml and resolution is 100ul. The electronic control decreases the repetitive strain injury. In addition, the remote control panel makes the operating process without the manual disturbance.

The mechanical bottle-top dispensers have four range covering a volume range from 0.5ml to 50ml. They are easy for operation, cleaning and maintenance following the user’s manual.

Based on the optional flexible discharge tube, our bottle-top dispenser presents the performance of fast and precise dispensing. We also offer the full-size adaptors with S40, GL32, GL38, GL25, GL28. The structure as:

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Extraction thimble sizes should be decided as per users’ specific applications. Every single size represents the particular practice of displaying the internal diameter and general length of the thimble in millimeters. Thus the extra allowance for the thickness of the thimble wall should be made when the external diameters are being calculated. The thimble should go through the narrower end of the top extractor socket, to allow 1-2 mm clearance.

Extraction thimble media options:

Cellulose

Cellulose extraction thimbles are made of superior cotton cellulose which can fit most Soxhlet extraction devices. Cellulose extraction thimbles can be used for the following purposes:

Fat determination of dairy products
Determination of pesticide residues in food products
Determination of organic compounds in washing agents
Extraction of additives from livestock feed
Solid particle like dust collection in air flows
Evaluation of liquid content in the concrete slurry

Glass Fiber

Highly pure glass fiber extraction thimbles are applicable for high-temperature filtration, up to 550C (1022F). Or it could be an alternative to turn to when the solvents used are incompatible with cellulose extraction thimbles. Glass fiber extraction thimbles can be used for the following purposes:

Gravimetric methods for hot environments
Gravimetric methods for acidic gasses
Extraction methods common to biochemical analysis

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Hawach summarized the advantages of QuEChERS in eight aspects.

1. Recovery Rate

QuEChERS technology has the advantage of a high recovery rate. Experimental data show that the recovery rate of large quantities of polar and volatile pesticides by QuEChERS is above 85%.

2. Accuracy

Laboratory workers can make use of the internal standard method to maintain correction with high accuracy in QuEChERS technology.

3. Analytical Range

The analytical range of pesticides by QuEChERS technology is wide. Pesticides including polar and nonpolar both can get great recovery rates by taking this technology.

4. Analysis Speed

The analysis speed of QuEChERS technology is fast that laboratory workers can deal with 6 samples within 30 minutes.

5. Use of Solvent

With less use of a solvent (0% use of a chlorinated solvent), QuEChERS technology can bring less pollution and lower cost in comparison with traditional techniques.

6. Operation

Easy operation of QuEChERS technology makes laboratory workers performing analysis quite smoothly without being well trained to have a command of advanced skills.

7. Safety

The container will be sealed immediately after acetonitrile is added inside, which reduces exposure between laboratory workers and the hazardous substances.

8. Sample Preparation

During the process of sample preparation in QuEChERS technology, less glassware is used and the whole equipment is simple and convenient for laboratory workers to conduct experiments and perform analyses.

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A diaphragm vacuum pump is mainly used in the fields of medical and pharmaceutical product analysis, fine chemicals, biochemical pharmacy, food inspection, public security criminal investigation technology, etc.

The advantages of a diaphragm vacuum pumps

1. Advanced design and technique.
2. High efficiency.
3. Long service life.
4. Does not produce pollution.
4. No working medium is required.
5. The gas exchange chamber is provided with filter material.

Applicable occasions of a diaphragm vacuum pumps

It is made of aluminum alloy die-casting, anti-corrosion spraying and plastic spraying, light and beautiful, wide application range. The air chamber adopts Teflon treatment. Therefore, diaphragm vacuum pumps have the feature of high corrosion resistance and can meet the requirements of various working environments.

Matters needing the attention of a diaphragm vacuum pump

1. Working environment temperature cannot exceed 55 ℃.
2. This product cannot be used at high altitude.
3. It is the precision instrument. Keep away from dirt and moisture.
4. Do not allow corrosive liquids or particulate matter into the pump. Water vapor, oil contaminants or other liquids must be filtered out.

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Some customers will react to their own PCR experiments. During the experiment, a large amount of long-term pipetting work has caused a great burden on their hands and caused certain damage! In fact, this situation is not uncommon, but everyone has not noticed it.

As early as the end of the last century, researchers investigated the pipette-related ergonomics and analyzed the use of pipettes between the upper limbs (hand, elbow, thumb, shoulder) and neck disease and relationship.

The results of the study showed that the proportion of hand and elbow pain in the use of pipettes was higher than that of people who did not use pipettes.

Moreover, the time of using the pipette has a greater impact on upper limb disease, and the proportion of hand pain in a person who uses the pipette for a longer period of time is higher than that of those who use the pipette for a short time. The time of the liquid device increases, and the proportion of hand pain increases! Unexpectedly, when the pipette was used continuously for more than 60 minutes, the proportion of hand pain was almost 90%!

It can be seen that the use of pipettes does have a certain impact on our health. Therefore, we must not ignore it. In the process of using the pipette, the repeated damage caused by the thumb, fingers, and wrists, the damage caused by muscle, nerve and tendon pain caused by long-term repetitive movement and overuse is called repetition. Repetitive strain injury (RSI), or repetitive strain, muscle damage, repetitive movements. Pipetting has been identified as a source of aggravation of upper extremity pain symptoms, especially in the case of more than 300 hours of pipetting per year.

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As one of the useful sample preparation technique, solid phase extraction can prevent many problems, such as incomplete phase separations, recoveries with poor quantity, waste of expensive fragile glassware, and extra disposal of organic solvents, which you may occur if you use the liquid/liquid extraction.

On the other hand, SPE takes quantitative extractions that are easy to perform with high speed and automated. So it is a more efficient way of extraction than liquid/liquid. To reduce solvent use and lab time, it is often used when we prepare liquid samples, extract semivolatile or nonvolatile analytes, and solid pre-extracted from solvents.

With the purity of the advanced extract, SPE is perfect for super complex analyzes. The right choice of SPE cartridges and sorbents will help you achieve a better result. Suitable with many different sorbents, SPE cartridges coincide with the filling materials of HPLC columns, such as reversed phase, normal phase, ion exchange, and the “mixed mode” materials.

The specifications of SPE cartridges we can find is as followed:
Volume: 0.01 ml – 200 ml
Particle Size: 5 µm – 250 µm
Pore Size: 40 Å – 450 Å

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The empty column is assembled from column joints, column tubes, and filters.

The HPLC columns joints are constructed with a low dead volume. The column joints are threaded assemblies at both ends, with 7/16-inch external threads on one end and 3/16-inch internal threads on the other end (standardized at home and abroad). The 7/16-inch external thread is connected to the 1/4-inch column tube (Φ6.35mm) and placed in the middle for sealing. The 3/16″ internal thread is connected to the 1/16″ (Φ 1.57mm) connecting tube, and a pressure ring is placed in the middle for the seal of the column joint.

In order to minimize the dead volume outside the column, when installing the HPLC columns, use a Φ1.57mm connecting tube to insert the hollow screw into the ring, and then tighten the hollow screw. The pressure ring is pressed and deformed by the hollow screw and then hung on the connecting pipe (the length of the pipe exposed after the connecting pipe passes through the pressure ring should be strictly controlled to 2.5 mm long or other fixed sizes).

In the column joints at both ends, a stainless steel filter (or strainer) is placed at each end of the HPLC column tube to block the column packing from being washed out of the column by the mobile phase. Each component of the empty column is made of 316# stainless steel, which can withstand the general solvent effect.

However, since the chloride-containing solvent is corrosive to it, it should be noted that the solvent and the connecting tube cannot be stored for a long time to avoid corrosion.

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The glass fiber filter is chemically inert and contains no binder. It is made of 100% borosilicate glass fiber. It has a capillary structure, can absorb more water than the same cellulose filter paper, has the characteristics of fast flow rate, high-temperature resistance and strong dirt holding capacity, and can filter fine particles. But in our company, we have two types of with binder and without binder. So when you going to buy it, you should know the type you need. As an important part of FRP products, glass fiber is widely used, and the application of filter film is very close to our daily life. The glass fiber membrane filters are extremely fine fiber, which has high filterability and high dirt carrying capacity and has good hydrophobicity and biological inertness.

Compared with other fiber materials and synthetic materials, glass fiber membrane filters have higher filtration efficiency and belong to deep filtration. Their main purpose is to use as a filter layer and directly on the membrane filter. Glass fiber membrane filters are used for routine monitoring of air pollution monitoring and special monitoring of solid contaminants, microorganisms, oils and acid mist in the air. It is used for the collection of highly efficient fine particles for water pollution analysis. It is an ideal product for collecting dust in the air and accurately measuring it. It can be used for pre-filtration of membranes to prevent clogging of membranes; large surface area uses glass fiber membranes for excellent retention. Different sizes of filters have specific requirements on the diameter of the pre-filtration membrane. Learn more about the different specifications of adhesive-free glass fiber filters:

MG A high-efficiency filtration is generally used for laboratory solvent buffer purification, air, and water pollution testing, in line with international standards
MG B filters and screens suspensions in water, sewage analysis, prefilters, suitable for bulk filtration.
MG C standard for wastewater and rainwater purification testing filters, cell collection, and hydrocarbon analysis.
MG D is generally used for pre-filtration.
MG F Efficient microparticle collection filter, protein purification for high-performance liquid chromatography liquid filtration.
MG G water filtration and testing.

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Activated carbon filter cartridge(CTO) is a new type of deep filter, it is made of high quality activated carbon as a raw material in the low hot melt adhesive composition of its structure, continuous extrusion molding.

The carbon core has excellent adsorption performance of granular activated carbon, and has effectively overcome the defects of carbon powder leakage in the use of all activated carbon filters.

It has the precision filtration characteristics of tubular elements, and can effectively remove organic matters, particles, rust, residual chlorine and peculiar smell in the liquid.

The performance characteristics:

1. adsorption, filtration, loading, catalyst
2. Resistant to corrosion by chemical reagents such as acid and alkali and organic solvents;
3. High filtering accuracy, large flow, small pressure difference, high-pressure strength, high pollution, non-toxic and tasteless, no secondary pollution;
4. Convenient disassembly is the replacement of bulk activated carbon more ideal new products.

The main purpose:

Activated carbon filter cartridges are ideal for liquid filtration in pure water, electroplating solutions, printed circuit boards, solvents, coatings, detergents, pharmaceutical water, beverages, and spirits industries.

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The fast liquid chromatography column optimization function, or “GO” function, converts the linear gradient into a step gradient and optimizes the elution conditions near the confirmed elution peak. First, purify a small portion of the sample with a small column and wait until the run is complete, select the Optimize button. Then select the target peak, a new, optimized, gradient-based elution method is automatically generated. Select a new column and collection scaffold, the separation method is automatically adjusted according to the size of the new column, and ready to run.

 

Flash column features

1. Excellent chromatographic peak shape
The flash column uses a new type of bonding and end-capping technology to provide perfect peak shape, which greatly improves the resolution and quantification of acid, base and neutral compounds at low and medium pH conditions. The accuracy of the analysis.

2. Excellent low pH stability
Compared to other brands of silica gel columns, the stability of flash columns at low pH results in longer column life.

3. Outstanding efficiency
So far, advanced ultra-pure silica fillers, combined with new bonding and end-capping technology, ensure high efficiency in flash columns and higher sensitivity.

4. Batch reproducibility is good
Flash columns achieve industry-leading column-to-column and batch-to-batch reproducibility.

5. Excellent mass spectrometry compatibility
The flash column is compatible with mass spectrometry and has sharp peak shapes, excellent selectivity, higher peak capacity and lower loss of bonded phase. In addition, the resolution and low back pressure characteristics of the flash column saves the cost and time of the analysis.

Flash column characteristics:
1. High load sample
2. Excellent stability under low pH conditions
3. Excellent peak shape
4. Outstanding efficiency

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Sample vial is a necessary product for pollution detection and a qualified special instrument.
Classification of sample vial
150ml, outer diameter 50mm* diameter 22mm* vial height 130mm;
250ml, outside diameter 70mm* diameter 30mm* vial height 140mm.
Sample vial – application of sampling vial (filter vial) for particle counter
1. Used for the collection of liquid samples for particle pollution test;
2. Used for holding high cleaning reagents;
3. Used for holding granular standard substances and standard samples.
Process of sample vial
The special sample vial for particle counter is made by adopting a complete set of technological processes such as high-precision ultrasonic cleaning machine, 1000-level clean air shower, drying, and sealing, etc. The sample vial cleanliness is a special sampling container for a particle counter to test the liquid pollution degree. This kind of sample vial is suitable for sample collection of various liquid particle test, containing high cleaning reagent, particle type standard substance, and standard sample.

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The main function of the microporous filtration membrane and syringe filter is to trap and filtering of the particles, bacteria and other impurities from the gas phase or liquid phase for separation, purification and purification purposes.

The following factors should be considered when selecting a syringe filter:

1. Filter media (chemical compatibility):
The first factor to be considered is the chemical compatibility of the filter media.
If the filter is resistant to organic solvents such as acids and alkalis. See our syringe filter chemical compatibility table for details of each.
2. Diameter
For column systems using 3um or larger particle size, 0.45um syringe filter or membrane can be used; for chromatographic system with less than 3um packing, or chromatographic system involving microbial growth, it is recommended A 0.20 um filter was used. For viscous solutions, pre-filtration can be carried out using a 1-5 um filter and then continually filtered with the corresponding filter.
3. Characteristics of the sample
1) Hydrophilic sample: A hydrophilic membrane is used. It has an affinity for aqueous based samples. Membranes also used such as: mixed cellulose esters, polyethersulfone (PES), Nylon, and the like.
2) Strong corrosive organic solvent: a hydrophobic film is generally used. Filters such as PTFE, polypropylene (PP)
3) Protein solution: Select a low protein adsorption filter, such as a PVDF filter.
4) Ion Chromatography: PES membranes are generally considered to be suitable for filtration of solutions with low inorganic ions.

4. Sample Volume
When selecting the syringe filter, consider the volume of the sample (that is, what size of the syringe filter is selected): Generally, when the sample amount is less than 2 ml, a 4 mm diameter micro-filter is used. The sample volume is between 2-10ml, and the 13mm diameter filter is suggested to use. When the sample amount is more than 10ml, the 25mm diameter syringe filter is suggested to use.

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Syringe filters are one of the types of filters. The structure design of the syringe filter is precise and the liquid is filtered smoothly. Internal space design is reasonable, so the residue rate is very low. In addition, the syringe filter has the following characteristics.

Characteristics of syringe filters

(1) Compared with traditional filters, the product is specially designed to withstand large blasting pressure which is not easy to crack.
(2) The edge part of the filter is threaded, which can play an anti-skid role. In addition, the humanized design makes the operation handier.
(3) The consistency of the analysis results is fully guaranteed by the stable quality of the filter membrane and the zero difference between different batches.
(4) The specifications are clearly marked to avoid confusion.

Use of syringe filters

The filter is usually combined with a syringe to filter samples of chemically turbid solutions. Most commonly used in chemical HPLC-MS/GC-MS analysis of liquids and gases for dust removal, bactericidal filtration, biological sample preparation, tissue culture media, microbial media, buffer solution and so on.

Operation steps of syringe filters

(1) Use a syringe to absorb the liquid to be filtered.
(2) Insert syringe filter into needle barrel.
(3) Exhaust the bubbles until the liquid drips out.
(4) Push the piston to make the liquid filter out.

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As mentioned before, Hawach Scientific is a dedicated manufacturer who focuses on R&D, manufacture, and marketing of micro-porous filtration and laboratory consumables products under ISO9001 quality management system.

Today we’d like to introduce you how to purchase filter paper from Hawach:

Firstly, you should know your filter paper is Qualitative filter papers or Quantitative filter papers, this is very important owing to different functions and different price;

Secondly, you should make sure about the size of your filter paper, is it around disc or square sheet, or Roll type? For the regular size of the disc, we have 55mm, 70mm, 90mm, 110mm, 125mm, 150mm, 180mm, 185mm, if need other sizes, please contact with us and discuss the more details. For square sheet the most common size is 60*60cm, if you need other sizes, also need to be checked with our sales department; For roll type, we only have width size of 123cm, one Roll is 100kgs, it is qualitative filter paper;

Thirdly, you should confirm the pore size or filtration speed, such as FAST(20-25um), Medium(8-11um), Slow(2.5-3um).

At last, you confirm the quantity, please send mail to info@hawach.com, then when the sales know your filter papers above details, it’s easy for them to send you the best price and lead time.

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If you want to dispense an aliquot of liquid from bottles, the bottle-top dispensers always provide the best results for your lab in the way of productively dispensing and no reagent wasting.

Depending on what you need, the important factors of choosing the bottle-top dispenser include the volumes and the type of the liquids you will dispense such as strong acids and bases, organic solvents, saline solutions, etc.

You always need to make sure that your liquid handling settlement is properly calibrated, and up to a high standard every single time. Calibrating bottle top dispenser is an important step to guarantee your liquids dispense is precise and accurate in the lab. Scientists prefer to use a pipette correctly calibrated, the situation is the same when dispensing liquids using bottle top dispensers. Be aware of checking out the bottle-top dispenser calibration all the time.

Combined with perfect calibrating equipment, the good quality bottle-top dispensers will be achieving the best results, saving your lab money with no more reagent loss, and avoiding the annoying repeated experiments and extra working hours in the lab.

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Extraction thimbles are a kind of cylinders used for filtering gas medium or liquid medium, which are divided into three categories in accordance with the material: cellulose, glass fiber and quartz fiber.

Cellulose exaction thimbles are mainly used for general Soxhlet extraction and filtering indoor toxic organic matter and dust.

Glass fiber exaction thimbles apply to the condition that is not suitable for cellulose exaction thimbles, such as the temperature higher than 120 ℃, or the strong acid environment.

Quartz fiber exaction thimbles cannot be made in China.

The installation of exaction thimbles

It is divided into vertical hoisting, oblique installation at a specific Angle, flange installation, etc, and the commonly used automatic cleaning methods of which include high-pressure gas pulse back blowing and mechanical vibration.

The application of exaction thimbles

An exaction thimble dust remover has appeared in Japan, some European and American countries as early as the 1970s. In recent years, it is widely used in cement, steel, electric power, food, metallurgy, chemical and other industrial fields with the advantages of large effective filtration area, low-pressure difference, low discharge, small volume, and long service life.

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QuEChERS method was originally applied to extract pesticides from fruits and vegetables. Whether under AOAC or EN stipulations, according to our products’ Application and Test Report, we can see that the combination of salting out and d-SPE-purification in the initial liquid-liquid extraction has shown more satisfactory results in the multi-residue analysis of pesticides, veterinary drugs, and mycotoxins in various foods and agricultural products.

Furthermore, Hawach QuEChERS solution has presented more advantages over other pesticide analysis products and technologies:
Easy to operate, high time efficiency, stable experimental results, high-cost performance, reduce labor costs, improve work efficiency, quick start kits selections, suit for both AOAC and EN stipulations, free match those materials of all kits, can customize your unique kit etc.

Hawach offers a wide range of sorbent blends to help you remove complex matrices from your samples:
C18 can be used to remove non-polar interferences such as fat;
PSA can be used to remove polar interferences, including sugars and organic acids;
A bulk adsorbent containing graphitized carbon black (CGB) and C18 can also be supplied to remove excess fat or high levels of chlorophyll.

No more hesitations, come to contact us info@hawach.com

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Vacuum filtration is an operation of evacuating the air below the filter paper to maintain the pressure differential across the filter medium. It increases the rate of filtration through the force on the solution over gravity.

When setting vacuum filtration, the first step is fitting the Buchner funnel to a suction flask. After that, we can connect the side arm of the flask to our vacuum pump which is of high quality, advanced design, and high efficiency.

Next step is to put the filter paper into the funnel and wash it with the solution. Don’t forget to get the right filter paper which has the right material, pore size, and the right size to your funnel. After that, you can decant the liquid phase into the funnel first and then add the precipitate.

To get the better result, you’d better add a little bit of wash liquid over the surface of the precipitate to wash it. The force of vacuum will draw the liquid through the solid slowly. At the same time, the precipitate will be dry out by drawing a current of air through it.

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Pipettes are common and necessary laboratory equipment in the laboratory, and the experimenter must be very cautious about their daily use. However, many people will ignore the related maintenance and maintenance of the pipette after use.

Precautions for maintenance:

1. Regularly clean the pipette, soapy water or 60% isopropyl alcohol is an effective way to clean the pipette, then rinse with distilled water, and finally dry naturally.
2. Before high-temperature sterilization, make sure the pipette can adapt to high temperatures.
3. If not used, adjust the range of the pipette to the value scale to keep the spring in a relaxed state to protect the spring.
4. Calibrate by repeating the method of weighing distilled water several times in a 20-25 degree environment.
5. Check for leaks during use. The method is to take the liquid and then hang it vertically for a few seconds to see if the liquid level is falling. If there is liquid leakage, the reasons are as follows:

a) whether the spring piston is normal;
b) whether the gun heads match;
c) If it is a volatile liquid (as is the case with many organic solvents), it may be a problem of saturated vapor pressure.

You can pipette several times and then pipette. For the pipette, not only must it be carefully protected during use, but also should pay attention to some maintenance items of the pipette after use. Only when the use is consistent before and after use can make the pipette have a longer service life and better efficiency.

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Solid phase extraction (SPE) is a separation process by which compound that is dissolved or suspended in a liquid mixture, thereby being separated from other compounds in the mixture according to their physical and chemical properties.

There are 4 general functions as below:

1.Matrix removal
For complex samples, the target compound needs to be separated from the matrix. The sample needs to be transformed into a suitable form to meet the needs of the analytical instrument.

2. Concentration
Enrichment of the target is a necessary process for trace analysis or preparation.

3.Clear up
Sample cleanup is achieved by a special interaction between the target compound and the functional groups on the SPE cartridgesto remove components and impurities that interfere with instrumental analysis. This way can avoid the interference of impurities on the target, improves the sensitivity of the analysis, and also prevent the instrument from damage by impurities.

4.Conversion solvent
Some analytical instruments have special requirements for analyte dissolution in solvents, but they can be converted by SPE cartridges. For example, when using the GC method to analyze semi-volatile contaminants in water, if injected directly, moisture will affect the separation and damage the GC column, thus requiring solvent conversion.

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The installation of the HPLC column should be carried out in the following three steps:

a. Unpack the HPLC column and confirm the type, size, date of manufacture, and solvent stored in the column.

b. Unscrew the sealing plug from the joints at both ends of the column and put it back in the box for spare.

c. According to the flow direction indicated on the HPLC column, connect the inlet end of the column to the outlet of the injection valve through the connecting pipe (if the conditions permit, it is recommended to use the guard column in front of the column); the outlet of the column is connected with the detector. The connecting pipe is a stainless steel pipe having an outer diameter of 1.57 mm and an inner diameter of 0.1 to 0.3 mm.

Both ends of the connecting tube have a hollow screw and a sealing ring for sealing. Always try to reduce the dead volume outside the column when taking over. After the connecting tube passes through the hollow screw and the pressure ring, insert it as far as possible into the end, then tighten the hollow screw clockwise until it stops, then use the wrench to continue to screw 1/4-1/2 turn clockwise, remember not to use too much force.

If the HPLC column is leaking after being pressurized by the mobile phase, use a wrench to continue to turn 1/4 turn clockwise until it does not leak.

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Overview of The Technology

Under the help of various permeable filter membranes, membrane technology provides engineering strategies to transport selected substances between two different portions.

To speak in a general way, filter membranes technology is utilized in processing
separating gas or fluid streams in a mechanical way.

Applications

Membrane processes do not require heating so that it consumes less energy than traditional thermal separation technology named distillation, sublimation, and crystallization. Due to its purified physical processing ability, both permeate and retentate portions can be involved.

Specifically, cold separation with the membrane is universally applied to the food, biology and pharmaceutical industries. Moreover, membranes make some separations be realized, which is not imaginable with the thermal methods.

Two Basic Models(to distinguish mass transfer)
In currently available filter membranes, there are two transporting approaches occur successively, especially existing in the ultra-filtration.

1.the solution-diffusion model
With the solution-diffusion model, transporting happens merely in diffusive condition.
*Be careful that the demanded component has to be dissolved in advance.

2.the hydrodynamic model
To operate hydrodynamically, transportation is accomplished in a convective environment, which requires smaller pore dimensions than other two isolated components’ diameters.

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Hawach Scientific Nylon membrane has natural hydrophilic, wide chemical compatibility, without surfactant. Nylon folding filter elements in the production process strictly control the production environment to ensure the quality and cleaning of the filter elements. The overall sealing of the filter element is processed by the hot fusion welding technology, which minimizes the degree of oxidation of the filter element and prolongs the service life of the filter element.

The filter elements can be cleaned with chemicals. Nylon and polypropylene, two membranes used to make filter elements, have chemical inertness, no fiber shedding and are safe. Nylon pleated filter cartridge produced by our company has a large filtration area, high flow rate, low resistance, and long service life.

Products feature

1. Using enhanced nylon film
2. Higher strength, better acid, and alkaline resistance
3. 100% integrity test before delivery
4. Pore size distribution is even, filter compatibility is good, practicability is wide
5. No fiber shedding, in line with the requirements of the pharmaceutical and food industry

Application

1.Beverage industry: pure water, mineral water, fruit juice, beer, and wine filtration
2.Pharmaceutical industry: various solvents and liquid filtration
3.Electronic industry: high purity water, distilled water terminal filtration

Specification data

Diameter : 5/10/20/30/40 inch
Pore size : 0.2-5.0 um
Sterilize:
Online steam sterilization ,(SIP):121℃,30min
High temperature and high pressure sterilization , 121℃,30min
Biosecurity :
Endotoxin : <0.25EU/mL (10inch)
Dissolution content : ≤25mg (10inch)

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Developed in the 1970s, flash column chromatography is the method of isolating and purifying a component from a mixture by passing the sample through the flash column filled with a gel.

The inventors of flash column chromatography were using medium pressure chromatography and short column chromatography to replace the long column chromatography. And then they found a new way of combining the pressure and short column together to avoid taking too much time and achieving poor recovery.

The technique of flash column chromatography is well known because it presents the faster flow rates of the solvent than simple gravity flow. The silica gel was used as the original gel to line the column. And the silica gel is still in practice widely nowadays.

The scientists in the lab use air pressure to drive a solvent through the silica gel column, following up with column compression. After the sample is applied, the solvent will pass the sample through the column. And then we can collect the purified components or fractions. The process often takes about 5-10 minutes.

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Overview

To determine the physical and chemical parameters of natural water, laboratory workers always use polyethylene and borosilicate glass sample vials for common sampling. Furthermore, it is better to use chemically inert material. The frequently-used sample vials have multiple types of narrow mouth, wild mouth and a screw cap with cork, rubber plug, and ground glass stopper.

These sample vials are easy to buy. If the sample vials are packed in a case and sent to the laboratory for analysis, the case cover must be designed to prevent the corks from loosening, so that the samples will not be spilled or polluted.

Sample Vial for Photoactive Substance

In order to prevent some photoactive substances including algae from light, we mostly use opaque or colored glass vials and keep them in a dark place during storage.

Sample Vial for Soluble Gas or Constituent

When collecting and analyzing samples with a soluble gas, the components will be changed throughout aeration. Narrow-mouthed vial with cone ground glass stopper can reduce air absorption to a minimum limit. The most important is that special seal is required during transport.

Sample Vial for Trace Organic Pollutant

In general, as plastic sample vial will interfere with highly sensitive analysis, laboratory workers always use glass or polytetrafluoroethylene sample vial for trace organic pollutant.

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Cellulose acetate (CA) syringe filters

Features: Cellulose acetate (CA) syringe filter has good hydrophilicity, low protein adsorption, and no nitrate.
Applications:
(1) groundwater filtration;
(2) biological and clinical liquid filtration.

Mixed cellulose (MCE) syringe filters

Features: Mixed cellulose (MCE) syringe filter has good hydrophilicity, high porosity and filtration speed, uniform pore size, ultra-low adsorption, and low filtration resistance.
Application:
(1) Sterilization and particle removal in the laboratory and small test process;
(2) Sterilization filtration of culture medium and culture solution;
(3) Determination of bacterial flora in water.

Polyethersulfone (PES) syringe filters

Features: wide chemical compatibility, excellent hydrophilicity, suitable for high-throughput, high-efficiency filtration, low protein adsorption.
Applications:
(1) Filtration of pharmaceuticals and biological products;
(2) Filtration of ultrapure water, filtration of chemical raw materials;
(3) Filtration of beer, beverages, mineral water, etc.

An activated carbon adsorption filter uses activated carbon as the filter medium. Activated carbon has adsorption and decolorization ability, which can remove impurities in the liquid so that the liquid can be purified.

The main raw materials of activated carbon used by an activated carbon adsorption filter are organic materials rich in carbon. These carbonaceous materials are converted into activated carbon in the activation furnace through pyrolysis under high temperature and a certain pressure.

The applicable scope

An activated carbon adsorption filter is used to prevent the contamination of the following equipment by pollutants in water and also can be used to improve the smell and color of water, which is pretreatment equipment in the water treatment process.

The adsorption and decoloration ability are mainly reflected in the following aspects.

1. Absorb organic matter, bacteria, colloidal particles and microorganisms in water.
2. Absorb chlorine, ammonia, bromine, iodine and other non-metallic substances.
3. Absorb metal ions.
4. Effectively remove color and smell.

The size of the product depends on the amount of water. There are mainly three materials: glass steel, carbon steel or stainless steel material.

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When filter paper is used in experiments, it is mostly used together with filter funnel and Brinell funnel. The filter papers should be folded into a suitable shape before using. But it should be noted that do not over fold, because this will lead to the breakage of filter paper.

The specific operation process is as follows:

1. Fold the filter papers twice in a row to form a 90-degree circular corner shape.
2. Open the folded filter paper in the form of three layers on one side and one layer on the other, making it funnel-shaped.
3. Fill the funnel-shaped filter paper into the funnel, and the edge of the filter paper is lower than that of the funnel. Then pour some water into the funnel mouth to make the wet filter paper close to the inner wall of the funnel. Finally, empty the remaining water.
4. Place the funnel with filter papers on the funnel rack for filtration. Then, a beaker or test tube for collecting filtrate is placed under the neck of the funnel, and the tip of the neck of the funnel is placed close to the wall of the container.

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According to the properties of solutions, the bottle-top dispensers are divided into three types.

The first one is the basic one. It is highly applied to the common solutions, such as the non-oxidative but a strong acid/base with a lower concentration, polar organic solvent and the solutions of acid, alkali or salt. H3PO4, HCL, H2SO4, NaOH are frequent here.

The second one is the organic one. It is used for the vast majority of organic solutions and the strong acid with high concentration. Let me list some examples. There are the organic solvents containing fluorine or chlorine, chloroform, peroxide, and some other solvents.

The third one is applicable to HF solutions. The plunger of the bottle-top dispenser is made of pottery and porcelain because HF solution can corrode glass.

The process of moving solutions by the bottle-top dispenser is totally closed, which effectively prevent the solvents’ volatilization, spatter and spill. That is safer than moving solutions by cylinders. We can even transfer the solvents with high density and volatilization in the petrochemical industry.

What’s more, chloroform is usually used as solvents for most plastics. It is often used for experiments in labs. However, it is easy to volatilize and poisonous. Transferring chloroform through the bottle-top dispenser can avoid it because of the closed conditions.

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Hawach will introduce cellulose extraction thimble from six technical parameters: material, temperature and forming time, DOP retention, size selection, porosity, and fitting accuracy.

●Material
The consistency of component content of extraction thimbles made of different materials and those made of the same material has a great influence on the determination accuracy of various detection and analysis.

Cellulose extraction thimbles consist of high-grade alpha cellulose/seamless noble cellulose and linters of cotton without any binding elements(60% high-clean poplar fiber +40% refined cotton fiber).

●Temperature and forming time
The relevant temperature parameters and forming the time of the cellulose extraction thimbles can reflect the tolerable working temperature to a certain extent and the requirements of special working conditions. Relevant parameters are as follows:
The heating temperature: 75℃;
The forming temperature: 10℃;
The forming time: 1Hour;
The maximum temperature is 100℃;

●DOP Retention
The DOP Retention is a reflex of retention ability. The DOP Retention(% @0.3) of cellulose extraction thimbles is 99.8% .

● Size selection
As shown in the figure below, ID represents the inner diameter of the filter cartridge, H represents the height of the cellulose extraction thimbles, and wall thickness reaches the thickness of single-sided thimbles.


●Porosity: Consistent high porosity ensures fast flow through.

●Fitting accuracy: High fitting accuracy for all available extraction systems.

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Today, if you go to a market, you can see various fruit and vegetables on sale, even you cannot tell which season they belong to. This is all due to modern technology and planting technique. On the one hand, we are researching on genetically modified food to enlarge its advantages and avoid its disadvantages at the same time, on the other hand, we have been exploring more advanced pesticide which can not only perform as weed killer but also as chemical fertilizer with no harm to the environment.

Whether genetically modified food or pesticide, safety is always our first and foremost concern. But how to detect pesticide residue in fruits and vegetables?

No doubt QuEChERS method. With Hawach QuEChERS kit, you can achieve your experiment results quick, easy, cheap, effective, rugged, and safe.

Whether you follow AOAC 2007.01 or EN 15662, whether you want the kit or absorbent only, you can always find your ideal choice in Hawach.

All Application and Test Report strengthen our confidence in improving your experiments. If you have more questions, just feel free to contact us with info@hawach.com.

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A few days ago, I wrote a summary of the filter membrane. Many customers said that no product had no truth. So what I wrote today is a product that needs to be used in combination with microporous filter membrane – the solvent filter device.

Technical parameters

The solvent filter device also called a solvent filter unit, solvent filter kit, chromatographic solvent filter.T he main components of the solvent filter device are triangle accumulator bottle (1L) sand core filter head, filter cup (300ml), fixed clamp, dust cover, rubber hose, rubber hose linker, and can be equipped with different filter kit and solvent direct extraction adapter.

Main features

The solvent filtration device of the high-quality glass material is with hard mechanical properties, poor resistant to more than 280 ℃ temperature; Smooth appearance and transparent glass with no bubbles ensure a uniform wall thickness.

The solvent filtration device with good pressure resistance and interchangeability can be used for high temperature and high-pressure sterilization.

The size and specification meet international standards and can be matched with foreign brands. International standard size, through the ISO9001 certification, can be matched with a variety of foreign brands; This product also has fast flow, standard grinding mouth, and good sealing performance.

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Hawach introduces pipettes from the pipetting speed of the pipette and precautions during storage.

First, the rate of liquid absorption. It is often seen in the laboratory that in order to “improve efficiency”, the user quickly releases the thumb during aspiration, which causes the liquid to quickly rush into the tip.

As everyone knows, this forces the liquid to form a turbulent state after entering the tip, so that for small and medium-range pipettes, a vapor mist that is invisible to the naked eye will enter the inside of the pipette, for a large-scale pipettes.

You will see the liquid flush directly into the inside of the pipette. The end result is contamination or even corrosion of the piston of the pipette, which is prone to cross-contamination of the sample and has an impact on accuracy.

Second, storage. A considerable number of users will put the pipettes directly on the test bench after the pipette is used. If it is neat, the pipette may be placed in the drawer. This is actually not good! During the pipetting operation, it is inevitable that liquid will enter the inside of the pipette.

In the flat state, these liquids will remain on the piston and other components, and after a long period of time, the piston will pollute the piston and even corrode the piston.

SPE cartridges, with a full name of Solid Phase extraction cartridges, is also called the SPE column( solid phase extraction column). The solid phase extraction column/cartridges is a pretreatment device for the sample being analyzed, which developed from the chromatographic column for extraction, separation, and concentration.

Applications of SPE cartridges

SPE cartridges are mainly used in the sample pretreatment of target compounds in farm product and livestock products, various food, environmental samples, and biological samples. SPE technology has been widely used in many industry analysis standards and national standards(GB/T).

Principles of SPE cartridge

SPE mainly comply with the separation principle of selective adsorption and selective elution by liquid chromatography. Based on the theory of liquid-solid chromatography, selective adsorption and selective elution were used to enrich, separate and purify the samples. It is a physical extraction process including a liquid phase and solid phase, which can also be approximated as a simple chromatographic process.

A more common method is to pass a liquid sample solution through an adsorbent, retaining the substance under test. Then select the appropriate strength of solvent to flush impurities, and then use a small amount of solvent to quickly elution material, so as to achieve rapid separation and concentration of the purpose of purification.

NH2 HPLC columns can be used in the positive phase or in the negative phase, but it should be noted that the positive phase solvent and the negative phase solvent are usually not mutually soluble. New NH2 HPLC columns are preserved in the positive phase environment under normal circumstances.

Preservation of NH2 HPLC column

For the reversed phase, it can be preserved with 95% methanol or acetonitrile for short term storage. Methanol should be replaced successively with isopropanol and chloroform, and finally preserved with n-ethane for long term storage.

The usage of NH2 HPLC column

1.For positive phase usage

It is not suitable to analyze the compounds containing aldehyde compounds, carbonyl compounds and reducing sugar. The mobile phase shall be completely degassed and shall not contain carbonyl compounds or peroxides. When replacing the mobile phase of NH2 HPLC columns, ensure that the new mobile phase is mutually soluble with the original column storage solution.

2.For reversed-phase

The ideal PH range is 3.0-7.0. The lower the PH is the more risk of hydrolysis. If there is buffer salt in the mobile phase, use the same proportion mobile phase without buffer salt to avoid the precipitation of buffer salt.

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The glass fiber filter is chemically inert and contains no binder. It is made of 100% borosilicate glass fiber. It has a capillary structure, can absorb more water than the same cellulose filter paper, has the characteristics of fast flow rate, high-temperature resistance and strong dirt holding capacity, and can filter fine particles. But in our company, we have two types of with binder and without binder. So when you going to buy it, you should know the type you need. As an important part of FRP products, glass fiber is widely used, and the application of filter film is very close to our daily life. The glass fiber membrane filters are extremely fine fiber, which has high filterability and high dirt carrying capacity and has good hydrophobicity and biological inertness.

Compared with other fiber materials and synthetic materials, glass fiber membrane filters have higher filtration efficiency and belong to deep filtration. Their main purpose is to use as a filter layer and directly on the membrane filter. Glass fiber membrane filters are used for routine monitoring of air pollution monitoring and special monitoring of solid contaminants, microorganisms, oils and acid mist in the air. It is used for the collection of highly efficient fine particles for water pollution analysis. It is an ideal product for collecting dust in the air and accurately measuring it. It can be used for pre-filtration of membranes to prevent clogging of membranes; large surface area uses glass fiber membranes for excellent retention. Different sizes of filters have specific requirements on the diameter of the pre-filtration membrane. Learn more about the different specifications of adhesive-free glass fiber filters:

MG A high-efficiency filtration is generally used for laboratory solvent buffer purification, air, and water pollution testing, in line with international standards
MG B filters and screens suspensions in water, sewage analysis, prefilters, suitable for bulk filtration.
MG C standard for wastewater and rainwater purification testing filters, cell collection, and hydrocarbon analysis.
MG D is generally used for pre-filtration.
MG F Efficient microparticle collection filter, protein purification for high-performance liquid chromatography liquid filtration.
MG G water filtration and testing.

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When selecting the filter bag, we need to take the following basics into consideration:

First, we need to consider the general application of the filtration. For example, the filter media applied for pharmaceuticals, food or cosmetics must be approved by the FDA. For EDI water filtering, we must select the ultra clean filter bag which is lint-free. For gas filtering, we must select the hydrophobic filter bag.

Next, we should understand the filtration mechanism of the bag filter system: the liquid flows from the inside of the filter bag to the outside of the bag, and the filtered particles are trapped. In the bag, bag filtration works by pressure filtration. Thus, we might as well consider the operating temperature, operating pressure, pH, operating conditions when we look into the material of filter bag we’ll use.

At the same time, we may refer to the chemical name of the fluid to be filtered and its taboo to rule out the material that shouldn’t be used as the filter bag for filtering such fluid then we turn to the right type of material. Manufacturers usually use PE, PP, PTFE, or NMO material for making filter bags.

Last, let’s make a wise choice out of various microns and sizes! The nominal accuracy does not have a standard that the industry has jointly identified and complied with. That is to say, A can set the nominal accuracy in 85-95%, while B is better at 50-70%. In other words, A’s 25-micron filtering accuracy may be equal to B’s 5 microns or finer.

For this problem, we HAWACH as the experienced filter supplier could help out. According to the viscosity and temperature of the filtration, we can calculate the size of the filter that’s needed, how many filter bags need to be installed and advise comprehensively per the generalized information.

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In order to evaluate water quality, laboratory workers need to analyze the chemical constituents of water. At the same time, they have to consider the interactions between each constituent and the factor of photolysis when choosing the sample vial. It is better to shorten the sample’s storage time and exposure time to light and heat. In addition, biological activity must be considered.
When choosing the sample vial, laboratory workers also need to think about the adaption to drastic changes of temperature, the resistance to rupture, the sealing property, the volume, the shape, the mass, the price, the reusability, etc.
We normally use sample vials which are made of polyethylene, fluoroplastics and carbonic ester to store inorganic samples. The frequently-used high density polyethylene sample vial is propitious to the analysis of silicon dioxide, sodium, total alkalinity, chloride, fluoride, conductivity, pH and hardness of water. Brown sample vial is fit for photoactive substance. Dissolved oxygen and BOD5 must be stored in special sample vials. Stainless steel sample vial is suited to keep high temperature or high pressure samples.
Glass sample vials are commonly used for the storage of organic and biologic samples. While plastic sample vials are for radionuclide and water with glass composition.

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End users would probably give priorities to the following incentives of the syringe filter.

The Coherence of MDA and Requirements

MDA here stands for material, diameter, and aperture. Usually, satisfying coherence is a basic requirement of customers so that suitable products can be well recommended according to this principle.

Product Quality

The chart below demonstrates details of relevant factors respectively.

Extractability
Whether impurities can be dissolved during the filtration.
Stability
This is extremely important not only for filtrum but also for filter paper, membrane, and cylinder.
Operating pressure
End users care about this most especially considering daily massive experiments.

Other Merits

1. A wide range of product series
It has been easier for customers to choose the most appropriate product.
For the diameter of syringe filter, there are 4, 13,25, 33, 55mm.ect. Apertures are from 0.1um to 10um, which applies to different volume capacities and filtration demands. Various products made out of distinct membrane materials meets buyers from numerous fields. Additionally,sterilization or non-sterilization, with a pre-filter or not, imported or exported joints of international standard are separately designed for clients from sterile laboratories, charging sample medium and for most syringes.

2. OEM service

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Sometimes, the users have own sorbent and just need an Empty flash column. Our company, Hawach Scientific is online to supply the Empty flash column. In 2019, we already add 2 sizes of Empty flash column as 60g and 100g. So we enlarge our size range of empty flash column as the below list:
Our empty flash columns are made from medical grade virgin PP cartridge and ultrapure sintered PE frits. This natural advantage makes it stable chemical resistance, the first on end of the column makes free leakage. The standard Luer-lock end fittings allow for quick, easy connection to the most of flash system.

In addition, we also supply for the empty column packing tools with the full of matched size. The tool helps you to pack the sorbent into column easily and improve the efficiency of your work. Hawach Team welcomes you come to inquire more information.

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It’s important to know the way to choose the right syringe filter for filtration. And the membrane materials used for manufacturing syringe filters often determine your choices. Let’s learn the different types of membrane materials for filtering in the lab.

As the most popular membrane used for the laboratory filtration, Cellulose Nitrate (CN) membrane has perfect wetting properties which can give the fastest rate of flowing with aqueous solutions.

Mixed with cellulose triacetate and diacetate, Cellulose Acetate membrane is strong enough in different directions, lateral and longitudinal. This types of the membrane also have a low static charge and a very low aqueous extractability. Its also has excellent solvent resistance to low molecular weight alcohols.

Compared to pure nitrocellulose membrane, Mixed Cellulose Ester membrane is good at providing a more uniform and smoother surface. This membrane can be used to count and analyze particles which contain in liquids.

With the strong and inherently hydrophilic character, Nylon membrane has good compatibility with a wide range of aqueous solutions, especially the alcohols and solvents we use in HPLC process.

Polyethersulfone membrane offers a fast flow rate and better chemical resistance, due to the good hydrophilic and low protein binding.

PTFE membrane can inert to most chemically aggressive solvents, strong acids, and other bases, which provides strong and highly porous.

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Hawach Scientific work for filter paper for more than 16 years, we are happy to see our products exported to the United States, UK, Germany, Dubai, Thailand, South Korea, and other countries.

We are not satisfied with our present achievement, this year our R&D department have good news: We have a new type of filter paper special for wine filtration, the specifications just as followings:

1. All of our filter papers all manufactured from High-quality cotton liners to ensuring quality;
2. Particle Retention: 7-10um;
3. Filtration Speed: Medium;
4. Basis Weight: 80g/m2;
5. Grade: Food grade;
6. 20*20cm, 40*40cm are regular size, if you need other sizes, we can customize for you.

Here is the photo of our filter papers:

If any question about the filter paper, please don’t hesitate to contact us!
Thank you for your time!

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The bottle-top dispensers are a useful tool to dispense reagents, media, chemicals, and solutions from bottles, containers, and into other vessels. With components of filling tube, piston or pump, discharge valve, and discharge tube, the bottle-top dispenser is a popular chemical method for transferring in many labs.

We can dispense a liquid accurately and precisely in a safe way by using the dispenser. You may concern about the chemical compatibility, viscosity, volume, frequency when selecting the bottle-top dispenser for your lab, and the budget too.

There are some important design features you should consider when you purchase the bottle-top dispensers, such as recirculation valve, autoclavable, and volume setting mechanism.

Recommended by in many labs, the bottle-top dispenser can recirculate the liquid as the scientist primes the dispenser. The feature can lower the cost by less chemical splashing and liquid lost. The fully autoclavable dispensers should be considered If autoclaving is required.

Make sure if the valves of the dispensers need to be loosed before autoclaving. The volume adjustment knob, volume adjustment dial, and electronic with premium dispensers are three designs of volume setting mechanism which is widely used in the lab.

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A. Cellulose Extraction Thimbles

1. 60% high purity grade polar fiber+40% refined cotton fiber no any binding agents which make it has stronger mechanical strength and stronger retention
2. 6 wall thickness optional to meet different retention and wet strength, dry strength increasing requirements or other special requirements.
3. DOP Retention 99.8%@0.3μm, Maximum temperature 100 ℃,
4. 30 sizes optional to fit for all your laboratory extractors.

B.Glass Fiber Extraction Thimbles

1. Low background response
2. Maximum temperature 600 ℃ compared to others’ 500 ℃
3. DOP Retention more than 99.99% (condition: >0.3 μm)
4. Weight loss less than 0.20%
5. 3 Sizes optional for use

Someone may ask how are we gonna choose the right size of Extraction Thimbles?

It’s indispensable to choose the appropriate size to match the normal use of the extractor. While most of the times the difference is only a few millimeters.

Remember one principle: The filter cartridge passes through the narrower end of the extractor and has a gap of 1-2 mm, and 5-10 mm above the top of the siphon. Pay more attention to the thickness while you are calculating the outside diameters.

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Package 1 QuEChERS extracting pesticide residues from plants
Extraction box: 50 ml centrifuge tube + AOAC/EN salt pack
2 kinds of buffer salts: General buffer salt for phase-separation and pH-adjustment;
Anhydrous magnesium sulfate completely separates water in the matrix from the acetonitrile extract.

Package 2 QuEChERS cleaning up the extracted mixture via absorption action
Purification box: 2 ml/15ml Purification tube with the adsorbent (PSA, GCB, C18, anhydrous magnesium sulfate) inside.
PSA can be used to remove polar interferences, such as adsorbed carbohydrates, organic acids, and pigments etc.
GCB adsorbs chlorophyll, mainly for high potency fat and pigment fruits and vegetables, such as eggplant, green vegetables, carrots etc.
C18 removes non-polar interferences, for example, avocado.
Anhydrous magnesium sulfate removes moisture from the substrate and is widely used in various foods.

Package 3 QuEChERS extracting and purifying the pesticide residues.
Extraction tube 1EA + Purification tube 2EA.

Package 4 Prevents local heat dissipation caused by salt agglomeration; makes the pH of the whole system more uniform; thus making the extraction better and saving extraction time.

Ceramic homogenizer 2ml/15ml/50ml three specifications

Easy, straightforward and almost can start without any training. Except for those 4 options, standard adsorbents, salt packs, ceramic homogenizers, etc. can also be customized or purchased separately.
 
 
 

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Introduction of Hawach scientific filtration manifold

Multifilter is designed and manufactured for the simultaneous filtration of multiple samples. At present, when the laboratory carries on the filtration to the solution, generally USES the glass material sand core filtration device, this kind of method can only filter one sample at a time, the filtration speed is slow, the efficiency is low, the artificial labor intensity is big.

For operators who need to filter multiple samples at the same time, it is more convenient to choose to use a multi-filter. Because each filter rack has its own control valve, only one vacuum pump can be used to support single or multiple simultaneous operations. All stainless bracket of the multi-gang filter can filter operation under the high temperature of 121 ℃. The aluminum alloy clamp design is reasonable and compact, which can easily combine the filter cup with the intermediate filter head and ensure the strict sealing without leakage.

Product Code: SLSSF03001

6-Branch Stainless Steel Vacuum Filtration
– Six of 300ml Stainless Steel(SS316L) funnel
– The 1000ml glass collection bottle
– Anodized aluminum spring clamp
– Support frit and base
– Two pieces of hosepipes. The whole set can be autoclaved at 121° C

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By revolutionizing liquid handling in the modern lab, the invention of electronic pipettes is one of the greatest advances in pipetting technology.

First, for scientists who don’t have plenty of time in the lab, any advantage that can save time on pipetting is welcomed. Divided into all sorts of shapes and sizes, and with a variety of different technologies incorporated into the design, the electronic pipette can increase productivity in the lab.

Second, You can always know your electronic pipette dispenses the volume accurately by the digital display and motor operation. At the same time, using electronic pipette can reduce the possibility of human error.

Third, the manual pipette requires more hand movement and effort to carry out the same liquid handling tasks then the electronic pipette does. The new technology helps scientists maintain and increase their accuracy and precision.

Finally, The multitude of features on electronic pipettes is available. Most electronic pipettes come in single and multi-channel formats and the multiple modes like pipetting, reverse pipetting, mixing, diluting and multi-dispensing. It helps scientists increase their efficiency.
 
 

What is SPE Cartridge?

The term SPE cartridges is short for Solid Phase Extraction cartridge. It is a kind of sample preprocessing equipment (extract, separate and concentrate) which is developed from the chromatographic column.

SPE cartridge is mainly used for preprocessing of the target compound in all kinds of food, agriculture and livestock product, environmental sample and biological sample. SPE  technology has been widely applied to a number of GB/T and industry analysis standards.

The volume of SPE cartridges refers to its adsorbing capacity of filler. For the cartridge with the matrix of the silica gel, the volume is 1-5 mg/100 mg in general, which is to say that the volume is 1% to 5% of filler’s mass.

Theory of SPE Cartridges

SPE technology is based on the theory of liquid-solid phase chromatography, using selective adsorption and elution to enrich, separate and purify the samples. It is a kind of physical extraction process of liquid phase and solid phase, and also a simple chromatographic process.

A common method used in the laboratory is to keep the analyzed matter in the liquid solvent sample by the adsorbent. Next, choose appropriate solvent to wash away the impurity. Then use small amounts of solvent to elute the analyzed matter quickly in order to gain fast purification and concentration.

Hawach introduced the properties and application range of HPLC column stationary phase in the silica gel matrix.

Silica gel matrix:

Silica gel, weakly acidic, has a strong memory, used to separate non-polar, weakly acidic compounds, oils, etc.;

C18, a silica-based uncapped reversed-phase C18 column with high bond and density, low loss, high recovery, etc.

C8 octyl, the retention of non-polar compounds is weaker than C18;

CN Cyano, a silica-based cyanopropyl column with moderate polarity for reversed phase or normal phase separation, suitable for carbohydrates and cationic compounds;

NH2 amino group, silica-based aminopropyl stationary phase, used for the separation of phenol and phenolic pigments, petroleum hexaphenol, sugars, drugs and metabolites;

PSA-propyl ethylenediamine, a stationary phase similar to NH2, PSA has two amino groups, which is more ion exchangeable than NH2, and PSA can also chelate with metal ions for extracting metal ions;

SAX strong anion exchange, bonded with quaternary ammonium salt functional groups, mainly used for the separation of weak anionic compounds;

COOH carboxyl group, the bonding functional group is a carboxylic acid, used for the separation of quaternary ammonium salts or other strong cations;

PRS propane sulfonic acid, the bonding functional group is a sulfonic acid, used for weak cations, widely used in the analysis of malachite green;

SCX strong cation exchange, bond, and the functional group is benzenesulfonic acid, used for separation of organic base compounds and biological macromolecule desalting.

a. Application

PP membrane filter is used to filter out bacteria and particles from the liquid in the pharmaceutical, electronic and biological manufacturing industry, brewing, clocks and watches, medical oil, lubricating oil, the fuel oil industry, and a scientific laboratory. Generally, PP membrane filter can remove bacteria when the pore size is less than 0.45 micron, used for removing particles by the types larger than 0.65 microns.

b.Specification

Membrane thickness (micron): 180-240
Pore size (micron) :0.1, 0.22, 0.45, 0.8, 1.0, 3.0, 5.0, 10.0
Diameter (millimeter) 150 200 300 400
special specifications can also be customized

c.Usage method

1. Place the membrane in a clean container and soak it in distilled water to make it all wet.
2. Fix the wet membrane into the appropriate filter (smooth side down) to prevent its leakage.
3. Leading the liquid to be filtered in from the inlet and empty air from the exhaust, and then begin to filter.
4. Keep operation pressure keep less than 0.3Mpa.

d. Attention

1. This product should be kept away from sharp objects.
2. It is suitable for room temperature and 60% relative to humidity preservation.
3. Please use this product in the effective shelf-life period.

e.Notes

1. This diaphragm is made of polypropylene, which is suitable for alcohols, ethers, acids, and ketones. It is not suitable for halogens.
2. The general working temperature of this product cannot exceed 65℃, sterilization temperature 125℃ for half an hour, withstanding 300 KPa.
3. Filtration membranes can only be used as the final stage of filtration. The solution must be pre-filtered through sand rods or filter paper first in order to avoid the blockage.
4. This product is only suitable for the filtration of the aqueous solution. It’s not suitable for gas filtration.

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Capsule filter, which is also called disposable filter, is composed of the outer shell and the filter. The outer shell is usually made of high temperature polypropylene material. This kind of polypropylene material on the surface of the capsule filter does not contain adhesives and other chemicals. The property of this material is to ensure that the sample is not polluted. The filter has filter membranes and pore sizes. People can choose the most suitable filter for their researches. And the filter can be sterilized under high pressure, which is applicable for filtering low-dose liquid, gases or precious low-volume liquid in the industry and so on.

 
According to the different characteristics of the capsule filter, different filter membranes are used. There are some common species of the different filter membranes. The hydrophobic polytetrafluoroethylene(PTFE)filter membrane is suitable for filtering solvents and corrosive solution, or air and gas. The hydrophilic polypropylene (PP) filter membrane is suitable for making the prefilter of reverse osmosis and ultrafiltration. It is used to filtering water solution or the solvent samples. The nylon membrane has the characteristics of fast flow rate and low extractable level, which is suitable for the filtration of large volume samples.

As a simple and fast absorption chromatography technique for the routine purification of organic compounds, flash chromatography is developed for the daily purification of reaction products in the lab, which is low costs and achieves separations of samples (0.01-10.0 g weight) in short time.
Flash chromatography is basically a compound of medium pressure and short column chromatography driven by the air pressure. The process is described as follows:
1, choose a solvent is chosen which gives the best separation.
2, select a flash column of the appropriate diameter which is machine-packed with high quality silica gel, propylamine group of silica gel and NH2. or other packs. You can check out three series of our flash column as StarFlash, PureFlash and DepuFlash.
3, fill the flash column with the solvent.
4, use pressure to push all the air from the silica gel rapidly
5, apply the sample, refill the flash column with solvent, and elute the sample.
Generally, it takes so fast (5-10 min)The time of eluting the components from the flash column. Small fractions are typically collected early in the elution while the larger ones are collected at the end of the chromatography.

The boric oxide can make the glass resistant to extreme temperatures, improves its resistance to chemical corrosion, and assures the integrity of the content. As the very popular material in the manufacture of scientific instruments, borosilicate glass is a type of glass including at least 5% boric oxide.
Meeting USP Type I and ASTM E438 Type I, Class A light requirements, our clear glass vials are made of low extractable borosilicate glass for superior chemical resistance and maximum visibility in the lab. For UV protection, the amber vials are made from borosilicate glass can protect light-sensitive products which meet the USP Type I light requirements of light transmission.
Presenting in a variety of different sizes, we have high-quality glass sample vials made of Type I clear and amber glass. Our sample vials are also available attached or purchased in three types of caps: screw-top, snap-top, and crimp-top sample vials. We ensure that with our sample vials, you will achieve consistent, reliable results all the time.

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ETo obtain accurate separation of your sample, mobile phase, and other liquid, the perfect tool that you need is laboratory filters. An analysis of physical specifications and performance specifications is required when selecting filters.

Physical specifications for laboratory filters include sample size, pore size, filtration, and filter shape. Sample size indicates the maximum amount that filters can accept, especially for syringe filter and centrifugal filters. Pore size indicates if the filters retain particles of a specific size with an efficiency rate less than 100 %, generally 90% – 98% upon different rating methods.

The effective filtration area refers to the total, usable filter area. Usually, the larger the filter area and the faster the flow rate at a different pressure, the larger the throughput volume before the filter get clogged.

Performance specifications for laboratory filters include flow rate and hold-up volume. Flow rate indicates the volume of a liquid flowing through the filter at a fixed pressure and temperature. Hold-up volume is the maximum volume that the filter can retain your sample. particle retention size, porosity, and maximum pressure also need to be concerned.

The primary feature of the vacuum filtration that it uses the classical oil-free pump with sand core filter bottle combination, which is suitable for most Laboratory filtration needs of universal filtering products. The characteristics of this product will be described in detail below.

1. There is no need for any working medium (no oil pump), so it will not cause pollution-free. At the same time, the gas exchange bin of the machine has filter material built in to ensure the purity of the air.

2. Because of the uniformity of the pore size, the product can guarantee the ideal vacuum and high air flow rate, so the filtration rate can be greatly increased.

3. Installed with a thermal power-off protector, when the temperature of the pump reaches 130 degrees Celsius, automatic power-off can protect the motor from damage.

4. The friction-free motion of the membrane will not generate heat and will not cause friction loss of the diaphragm.

5. An automatic cooling and exhaust system is designed to ensure 24-hour continuous operation. Moreover, Teflon is used to treat the surface of the anticorrosive pump contacting with the gas, so it has complete chemical corrosion resistance.

Qualitative filter papers usually apply to filter at atmospheric pressure, which uses the ability of the material to remove particles to separate the liquid and solid of the sample. It covers most of the laboratory applications, is used commonly for liquid clarification and, sometimes, for qualitative analysis and purification of the deposits.

In the industrial filtration, it is commonly used to separate solids or extract liquids from solution as a filter material, not as chemical analysis filter paper. The Hawach qualitative filter paper has two categories: standard grade products and wet strength grade products. Users can select from either product depending on their requirements.

Standard Grade qualitative filter papers

Standard grade qualitative filter paper is frequently used in conventional filtration. There are several models of its different particle retentions and filtration speeds.

Usually, the slow filtration speed ones which have stronger separation ability by high adsorption are suited for the chemical analysis. In industrial, medium particle retention, medium filtration Speed models are especially suits to the analysis. Besides, the fast filter paper is thicker and has a higher load which can be used for filtering culture media and colloid substances.

Product parameters

Wet Strength grade qualitative filter papers

Considering some special requirements of users, Hawach developed wet strength qualitative filter paper on the basis of standard grade products. The chemical stabilizer was added to the materials of this kind of filter paper to improve the breaking resistance significantly. However, wet strength is not recommended for Kjeldahl nitrogen determination for the nitrogen elements from the chemical stabilizer. Users can select any model to meet your specific needs.

Product parameters

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As an indispensable experimental instrument for laboratory liquid operation, the bottle-top dispenser has the following characteristics.

(1) The setting operation is simple, and the protective gloves can be worn to operate directly in the process of operation. In addition, it has an efficient set locking device, which can avoid the occurrence of unexpected volume changes in the operation process to the greatest extent.
(2) Its performance is stable and the calibration is convenient.
(3) For the large-capacity liquid distributor, it also has the function of micro-adjustment, which can ensure the accuracy of liquid distribution when large amounts of liquid are distributed.
(4) It can achieve a fast volume setting and has a precise calibration design.
(5) It is equipped with a smooth and precise piston, which can slide up and down, making the operation more convenient and comfortable.
(6) Bottle-top dispenser is equipped with a safety cap for drainage pipe, which can avoid contact with reagents. This unique design makes it easy for operators to install or disassemble even when wearing gloves.
(7) The suction tube is transparent and suitable for reagent bottles of various sizes.
 
 

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A more efficient way to extract compounds from solid materials—Soxhlet extraction (also known as sand extraction).

In the laboratory, Soxhlet extractor uses solvent reflux and siphon principle, so that the solid substance is continuously extracted by pure solvent, which saves solvent extraction and works more efficiently.

The first step ground the solid material before extraction to increase the area of solid-liquid contact. The second step places the solid powders in an Extraction Thimble. The third step put them in an extractor, connect its lower end to a round bottom flask which contains the solvent and connect the higher end to a reflux condenser. Now all the preparatory work is completed.

So Soxhlet extractor, extraction thimble, and the solvent are the 3 key factors for Soxhlet extraction.

Hawach offers 2 kinds of options, cellulose extraction thimbles, and glass fiber extraction thimbles.

General Soxhlet extraction, Indoor dustfall, toxic organic substances (phthalic acid), so you can choose cellulose ones.

Operating temperature above 120 °C, strong acid and other substances which cellulose extraction thimbles cannot apply to, so you can choose glass fiber ones.

You can compare price but cannot tell quality only from words and pictures. No worries, Contact us to get samples!
 
 

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Take the example of pear test to check whether a pear is up to the standard.

Prepare the environment

The first step: Suitable Acetonitrile salting-out extraction environment was prepared. Make the pears into a puree, take 10g to QuEChERS centrifuge tube of 50ml. Add extract solution (acetonitrile) and Salt into acetonitrile solution(to create an aqueous environment ), then repeatedly shaken to ensure that the pesticide is dissolved into acetonitrile solution. QuEChERS Block ceramics to vortex can be added to accelerate the homogenization process.

Dispersive and extraction
The Second step, dispersive and extraction twice. Vortex the sample vigorously for seconds and then centrifuge for minutes. The resulting sample will show three layers finally: acetonitrile and the extracted compounds of interest is the top one. The remaining solids from the sample are in the middle layer. Aqueous, containing the excess salts from extraction salt packed is the lower layer.

Transfer the top acetonitrile and the extracted compounds layer to the prepared tube and add into adsorbents as a purification agent which will remove matrix interferences. Vortex and then centrifuge the tube containing the adsorbents for minutes again. Remove the supernatant after secondary centrifugation and finally get the pure solution containing pesticide residues.

Analyze

The third step, Analyze. Analysis of the concentration and content of pesticides, determine whether the standard

Hawach glass solvent filters is an important part of laboratory filtration, and many customers often encounter cleaning problems when using glass solvent filters. The conventional cleaning methods mainly include the following:

1. Soaking with an acidic solvent: The advantage of this is that the particles that are clogged in the filter gasket can be melted, but the problem of discoloration of the filter gasket is not possible, and there is no way to effectively improve it. And the effect of cleaning is also uncertain.

2. High-pressure water gun flushing: Through the strong water pressure, the particles that are blocked in the filter element are flushed out, but the effect of this method is effective.

3. Ultrasonic cleaning machine cleaning: It is also a physical cleaning method, which is better than high-pressure water gun cleaning, but has no effect on color contaminated filter elements. At the same time, the customer needs to purchase the device.

In summary, the various methods of cleaning the filter core have certain limitations. Once the filter element is contaminated, it cannot be restored to the factory performance. Therefore, in general, customers are advised to purchase according to the actual user requirements. Customers who must use sand core glass materials should purchase them. Other customers should try not to use this material.

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In laboratories where the pipettes are used frequently, it is often heard that the sound of tapping the tips is one after another, adding a bit of music to the boring laboratory life.

When you look into it, the user is afraid that the tip can’t be tightened. After the tip is attached to the pipette, tap it again in the tip box several times. It is hoped that the impact of the pipetting is ensured by such an impact force. Where is this operation wrong?

1. Under the action of impact, the pipette tip may be deformed to affect the precision of pipetting;
2. The part of the pipette sleeve that contacts the tip passes through a number of strong frictions, which gradually becomes rough and it is difficult to ensure the sealing property, and in order to achieve a good sealing property, a larger impact force is required, and the vicious cycle starts;
3. The small-scale pipette has a relatively small handle, which is likely to become a fishing hook under the continual impact of the impact;
4. Sometimes this impact is greater than the force that the pipette falls on the ground, and some of the precision parts in the pipette are at risk of being overwhelmed and strike.

SPE cartridges, with a full name of Solid Phase extraction cartridges, is also called the SPE column( solid phase extraction column). The solid phase extraction column/cartridges is a pretreatment device for the sample being analyzed, which developed from the chromatographic column for extraction, separation, and concentration.

Applications of SPE cartridges

SPE cartridges are mainly used in the sample pretreatment of target compounds in farm product and livestock products, various food, environmental samples, and biological samples. SPE technology has been widely used in many industry analysis standards and national standards(GB/T).

Principles of SPE cartridge

SPE mainly comply with the separation principle of selective adsorption and selective elution by liquid chromatography. Based on the theory of liquid-solid chromatography, selective adsorption and selective elution were used to enrich, separate and purify the samples. It is a physical extraction process including a liquid phase and solid phase, which can also be approximated as a simple chromatographic process.

A more common method is to pass a liquid sample solution through an adsorbent, retaining the substance under test. Then select the appropriate strength of solvent to flush impurities, and then use a small amount of solvent to quickly elution material, so as to achieve rapid separation and concentration of the purpose of purification.

Hawach Scientific sorts HPLC out of two series which are Xchroma and Echroma.  Xchroma columns possess many and complete types of stationary phase(23 in total) with reliable qualities, while another one is cheaper among lower prices.

Essential Technical Parameters

Naming Rule
It consists of the item number, description, and package(pcs/pk).
For instance, SLHC18A32310 stands for C18 Aqueous HCLP column from Hawach with the particle size of 3um, the inner diameter of 2.1mm and column length of 130mm.

About Guard Columns
Since HPLC columns can be broken by congestion, some labs especially install a guard column before HPLC to protect it and expand the usage span.

PTFE stands for Poly Tetra Fluoroethylene. People generally call it non-sticking lining or easy-cleaning material. The material of PTFE has the characteristics of antiacid and antisolvent, which means it is hardly insoluble in all solvents. And PTFE is heat-resistant and with low friction coefficients. People always not only use it for lubricating but also regard it as the ideal coating material for the lining of water pipes.

PTFE membrane is a kind of material named ultra-fine fiber glass coated with PTFE resins. Its durability、fireproofing and antifouling property are all outstanding. The PTFE membranes are usually white, have high transmittance and the ability to maintain its performance for more than 25 years.

PVDF is the abbreviation for Polyvinylidene Fluoride. PVDF membrane is from PVC membrane that is coated with PVDF resins on it, which is better than PVC membrane in durability. PVDF membrane is a kind of solid-phase carriers for the western blot in common use. It is hydrophobic.

The smaller the aperture of the PVDF membrane is, the firmer the PVDF membrane is. There is an interesting phenomenon that PVDF membranes are popular than PTFE membranes in the northern territory. Maybe the reason is that the glass transition temperature of PVDF membranes is close to 40 degrees below zero, it is better in low-temperature resistance.

Hawach scientific takes filtration technology as its core and manufactures high-quality filtration products. Our products after years of research and development, the use of advanced technology and first-class production equipment, to provide customers with all kinds of high-quality filter products.

At the same time, Beijing technology is the membrane separation, concentration technology as the guide, is committed to water treatment high-tech products research and development, is set production, sales as one of the high-tech enterprises.

Polypropylene (PP) pleated filter cartridges are widely used in food, medicine, biology, brewing, dairy products, beverage, semiconductor, water treatment, and other industries. The PP pleated filter cartridges core made by Hawach scientific co., Ltd. has a uniform pore size distribution, high flow rate, and large pollutant retention. Polypropylene is widely used in many fields because of its wide chemical compatibility.

Products feature

1.All polypropylene structures
2.Adopt gradually dense fiber material
3.0.1 to the 40um aperture
4.High surface area
5.Wide chemical compatibility
6.Adopt hot welding technology
7.Low differential pressure, long service life

Application

1.Food and beverage industry: mineral water, juice filtration
2.Chemical industry: organic solvent filtration
3.Petroleum industry: pre-filtration by water injection
4.Electronic industry: high purity water pre-filtration
5.Pharmaceutical industry: liquid medicine filtration

Specification data

Diameter : 5/10/20/30/40 inch
Pore size : 0.2-5.0 um

Sterilize:
Online steam sterilization ,(SIP):121℃,30min
High temperature and high pressure sterilization , 121℃,30min

The most important process of the whole purification is selecting the most suitable Flash column. And now we will talk about the key content of the column: stationary phase. Stationary phase, commonly known as filler, is the most central part of chromatography. When we choose the variety of the stationary phase for the chromatography, we should define three aspects: a substrate, bonded phase and substrate parameters.
The substrate is the basic material of the stationary phase. There are three kinds of materials used to obtain substrates, which are the inorganic materials, organic materials, and composite materials. The inorganic materials include silica gel, alumina, etc. The organic materials are mainly polymer materials such as gelatin. And the composite materials usually refer to the materials which are combined inorganic materials and organic materials by means of hybridization, coating and coating. Silica gel is the most widely used substrate in flash purification.
The bonded phase is used to modify the substrate or bonding the different groups, which forms different types of stationary phases.
The substrate parameters contain the shape, particle size and pore size. For instance, the widely applied silica gel substrate is usually divided into the spherical and the amorphous. And the two types of silica gel have different particle size. All the parameters should be referred to according to the requirements of purification.

In order to evaluate water quality, laboratory workers need to analyze the chemical constituents of water. At the same time, they have to consider the interactions between each constituent and the factor of photolysis when choosing the sample vial. It is better to shorten the sample’s storage time and exposure time to light and heat. In addition, biological activity must be considered.
When choosing the sample vial, laboratory workers also need to think about the adaption to drastic changes of temperature, the resistance to rupture, the sealing property, the volume, the shape, the mass, the price, the reusability, etc.
We normally use sample vials which are made of polyethylene, fluoroplastics and carbonic ester to store inorganic samples. The frequently-used high density polyethylene sample vial is propitious to the analysis of silicon dioxide, sodium, total alkalinity, chloride, fluoride, conductivity, pH and hardness of water. Brown sample vial is fit for photoactive substance. Dissolved oxygen and BOD5 must be stored in special sample vials. Stainless steel sample vial is suited to keep high temperature or high pressure samples.
Glass sample vials are commonly used for the storage of organic and biologic samples. While plastic sample vials are for radionuclide and water with glass composition.

Hawach Scientific Co., Ltd is main laboratory supplies and industrial filter manufacturing enterprises, from raw materials and production process to ensure the maximum quality monitoring, each batch of a strict quality testing and product warranty. At present, users are distributed in more than 80 countries around the world, nearly 200 quality dealers. Hawach has a good filter production technology, with 500 square meters of dust-free workshop, to ensure the quality of production.

Hawach scientific Syringe filter membrane material

1. Nylon syringe filter
Strong alkali resistance and organic liquid, natural hydrophilic
No need to soak before use, uniform aperture, good mechanical strength, thread interface design

2. Mixed cellulose syringe filter ( MCE )
High porosity and good closure
Not resistant to strong acid, strong alkali solution, and most organic solvents
It is most suitable for the filtration of aqueous solution in the water machine. Unique threaded interface design

3. Cellulose acetate syringe filter ( CA )
Natural hydrophilicity
Low protein adhesion, suitable for aqueous solution treatment
No nitrate.Suitable for groundwater filtration
Uniform aperture structure; Wide aperture selection; Retention of granulosa cell collection

4. Polyethersulfone syringe filter ( PES )
High solvent recovery and small residual; High capacity
Extremely high microbial filtration capacity; Unique threaded interface design
Low protein adsorption, low solubility

5. Polyvinylidene fluoride syringe filter ( PVDF )
Hydrophobic film, no moisture absorption, easy to constant weight
Heat – resistant and repeated pressure sterilization
Resistance to chemical corrosion and oxidation; Threaded interface design

6. polytetrafluoroethylene syringe filter ( PTFE )
Excellent chemical resistance;
High-temperature resistance, acid resistance, alkali resistance, with a strong hydrophobic
Both hydrophilic and hydrophobic membranes can be provided to meet the requirements of different liquid filtration

7. Glass fiber syringe filter ( GF )
Natural hydrophobicity
Flux; A large amount of sludge
Good mechanical strength

A filter paper is an effective filter medium and has been widely used in various fields.

The technical indicators of a filter paper can be divided into two aspects: one is the filter characteristics and the other is the physical characteristics. Filtration characteristics include permeability, maximum pore diameter, and average pore diameter. Physical properties include quantification, thickness, stiffness, rupture resistance, resin content, etc.

Types of Filter Papers

There are three kinds of filter papers, which made of different materials with different properties for different purposes. One is an ordinary filter paper for general occasions. Two is a glass fiber filter paper for high-temperature conditions. Three is a polypropylene filter paper for ultra-clean.

Application of Filter Papers

Paint filter papers can effectively filter the paint, oil, glass raw materials, epoxy, tar, liquefaction of workpiece, plastic, ceramic, dye, painting, porcelain. The filtering effect is 99.99%.

High-efficiency filter papers, made of glass fiber, are ideal air filter selection with the characteristics of uniform fiber distribution, large dust capacity, small resistance, and high strength, which are widely used in the defense industry, electronic instruments, medicine, food industry, and other fields.

Filter paper has excellent filtration property and strong absorption performance on liquid. Scientific workers use filter paper as a kind of media in analytical laboratories to separate solution from solid. Currently, there are mainly three kinds of filter papers which can be purchased in domestic market: quantitative filter papersqualitative filter papers, and chromatography qualitative filter paper.

During the manufacturing processes of quantitative filter paper, the pulp is processed by hydrochloric acid and hydrofluoric acid. After washed by distilled water, most of the impurities inside the paper fiber can be filtered so that the filter paper is fit for precise quantitative analysis.

Types of Filter Paper

Domestic produced quantitative analysis filter paper falls into three types: fast speed, medium speed, and low speed. They are marked with a blue belt (fast speed), white belt (medium speed) and red belt (low speed) respectively. Commonly, there are two shapes of filter papers you find in the market: round and square. The former one is always with the diameter of 9 cm to 18 cm, while the latter one is with the dimension of 60 cm x 60cm and 30 cm x 30 cm.

General Notes of Using Filter Paper

1. Make use of natural filtration to separate the liquid from solid.
2. Considering of low mechanical strength and tenacity of filter paper, make sure of using less suction filtration.
3. It is better not to filter hot concentrated sulfuric acid or hot concentrated nitric acid through filter paper.

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Firstly, let’s divide those bottle-top dispensers into 3 groups according to their materials

A. Highly corrosion resistant materials such as PTFE, PFA, boron silicate, platinum, etc.

Application: Resistant to high-temperature sterilization (121℃), withstand most of the acid, alkali, organic and inorganic solvents; can be fine-tuned for different solvent physicochemical properties; three-function valve’s standard configuration recirculation function can avoid solution Waste, and unique wiper seal ring effectively reduces piston expansion and crystallization.

B. Made of ETFE, FEP, PFA, PP material

Applicable to general acid and alkali and low concentration of strong acid and alkali and salts, such as H3PO4, H2SO4, NaOH, KOH, etc.
Maximum pressure 500 bar, maximum viscosity 500mm2/s, maximum temperature 40°C, and maximum liquid density is 2.2g/cm3. Easy to calibrate.

C. Almighty / hydrofluoric acid dispenser

Suit for hydrofluoric acid, strong acid, nicotinic acid, alkali, solvent, and extremely dangerous liquid. Integrated PTFE structure, no spring structure in drain valve, no corrosion and metal ion contamination reagents, suitable for trace analysis. Avoid leakage of niacin/odorous chemical liquid odor with a safety valve.

We can also divide bottle-top dispensers into two big categories, one for biological laboratories and biological use. One for chemical, chemical engineering, trace analysis, and harsh environments.

Suitable for Soxhlet-type and other similar devices, the extraction thimbles are used to adapt a sample of solid material to extract certain components out, with the addition of sufficient and appropriate solvent.

Cellulose extraction thimbles which are made of high-quality alpha cellulose cotton linter. Their main features of high purity, the strong mechanical structure and retentivity offer a special advanced combination for the scientist in the lab.

As its high purity of the materials makes the results reliable and repeatable, cellulose extraction thimbles are perfect to meet the requirement of higher retention and increased wet or dry strength or rigidity in the lab. And its maximum working temperature is 120ºC.

Suited for fat extraction in the food industry, extraction of polymers and environmental pollutants determination, the key point of choosing cellulose extraction thimbles is to fit extractors perfectly.

The references sizes (internal diameter and the length) and an extra allowance for wall thickness should be concerned when external diameters are relevant. the wall thickness of the standard single thickness thimbles is about 1 mm, while the wall thickness of the double thickness ones is about 2 mm.

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Extraction is often susceptible to matrix interference. One analytical method is fine in this matrix but can become problematic in another matrix. If we encounter such a situation, how can we improve the QuEChERS method to overcome it?

For pesticide residues, most of the food samples do not exhibit matrix interference except for some dry and greased samples. However, for some complex samples such as tea, traditional Chinese medicine, spices, liver and citrus oil, regardless of the QuEChERS method we apply, there is always the adsorption of the substrate on the pesticide residue. This is related to the method itself.

When the matrix contains impurities similar in structure to the analyte, it is difficult to purify it by the sample pretreatment process. Of course, some means such as adjusting the extractant, adjusting the pH, adding salt, changing the volume ratio, adding water, adding adsorbent can be of some help.

For example, acidic herbicides like phenoxyalkanoic acids tend to form covalently bonded residues. Such legally used pesticides are quite typical and therefore must be released prior to liquid-liquid extraction. Usually, we can firstly perform alkaline hydrolysis for 30 minutes by adjusting the pH to 12, and then have it return to neutral for QuEChERS extraction.

Basic Knowledge of Vacuum Filtration

Based on the principle that under the same pressure (vacuum degree), the vaporization temperature of the water is lower than that of oil, scientists make practical equipment which is called vacuum filter.

In fact, vacuum filtration is the most widely used and mature filtering method both in theory and practice. Like other cake filtration methods, porous filter media is also used to support the filter cake in vacuum filtration technology. However, the difference is that less driving force is used in vacuum filtration so that the technology is applicable for some special cases.

Anti-Corrosion Vacuum Filtration in Laboratory

Talking about laboratory vacuum filtration, anti-corrosion vacuum filtration equipment is a kind of special and professional filtering product. Other than solvent filtration such as suspended solids, microorganism, culture medium, buffer solution, and cleaning solution, vacuum filtration is always used for filtering of the mobile phase, organic solvent, and electrolyte. These samples are strongly corrosive and some can produce volatile gas.

If you use common or inapplicable filtration equipment, it will lead to cracking and deformation of the container, and, more seriously, it will corrode the inner valve plate and further damage the entire equipment. That is why anti-corrosion vacuum filtration equipment is different from common solvent filtration equipment in material and design.

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1. Capacity setting
For the adjustable pipette, it is usually operated in the range of 10% to 100%. The optimal pipetting capacity is in the range of 35% to 100%. At this time, it is less affected by the operation technique and can better protect the pipetting. Accuracy and precision. For example, to remove 600 uL of liquid, it is best to choose a 100 to 1000 uL adjustable pipette instead of 500 to 5000 uL.

2. Install the tip
Installation method: Insert the lower end of the pipette vertically into the tip, turn it left and right, and tighten it.

Be careful not to use excessive force, otherwise, the internal components will be loose, and even the knob of the adjustment scale will be stuck or the pipette sleeve will be bent.

3. Rinse the tip
When an organic solvent or a highly volatile liquid is removed, a volatile gas forms a negative pressure in the sleeve chamber, causing leakage. Rinse the pipette tip 4 to 6 times to make the gas in the sleeve room saturated, and the negative pressure disappears automatically, which can effectively prevent liquid leakage. However, do not rinse the tip when the sample temperature is very high or low.

4. Aspirate
There are two ways to aspirate: positive aspiration, reverse aspiration.
Positive aspiration refers to the normal method of aspiration. Press the button to the first step to release the solution and release the button. Press the first gear first, then press most of the liquid, then press the second gear to discharge the remaining liquid.

Reverse aspiration refers to pressing the button directly to the second gear and then releasing it so that more liquid will be inhaled. Just press the first gear when the liquid is discharged. The multi-inhalation liquid can compensate for the surface adsorption inside the tip. The reverse aspiration is generally used in combination with the pre-flushing and aspirating method and is suitable for viscous liquids, volatile liquids and small volume pipetting.

5. Draining
There are three ways of draining: draining along the inner wall, draining above the liquid level, and draining below the liquid level. The usual “draining along the inner wall” steps can be seen below:

(1) Stick the tip of the nozzle to the inner wall of the container and keep it inclined from 10° to 40°, and smoothly press the button to the first gear. After a slight stop, press the second gear to discharge the remaining liquid; when discharging dense or viscous liquid, stay The time is a little longer.
(2) Press the button and lift the pipette to lift the tip of the container out of the container wall.
(3) Release the button.

6. Remove the tip
The tip can be removed by pressing the tip ejector with a little force. If the tip is installed too tightly, it can be removed by hand. Discard the tip into a suitable waste collector.

Normally SPE cartridge has two basic adsorption modes: target compound adsorption mode, impurity adsorption mode; 5 operation modes: gravity operation, manual positive pressure, centrifuge, negative pressure and positive pressure mode.

Now let’s review the whole process step by step. (Here we take target compound adsorption as an example)

Step 1: Choose your right SPE cartridge
Step 2: Conditioning. Rinse the cartridge with a suitable solvent to increase the contact surface area of the target compound with the adsorbent and enhance the retention of the target compound.
Step 3: Sampling. Make sure the SPE Cartridge is wet before sampling. Choose one operation mode after sampling and control the flow rate during extraction.
Step 4: Washing. Selectively elute the weakly adsorbed impurities with a weak solvent to reduce the interference of the impurities on the target compound during the analysis and prolong the life of the instrument. No influence on the recovery rate of the target compound is the premise.
Step 5: Elute. Elute the target analyte. Don’t forget to have a drying process before elution. The excessive presence of water can have an adverse effect on elution efficiency, subsequent analytical means, and concentration.

The cation chromatography column is a kind of high-performance liquid chromatography, which is a liquid chromatography method for analyzing anions and cations. The method has the advantages of good selectivity, sensitivity, rapidity, and simplicity, and can simultaneously measure various components.
The catalytic column injection system
There are three main types of ion chromatography injections: pneumatic, manual, and automatic injection.

First, the manual injection valve
The manual injection uses a six-way valve, which works in the same way as HPLC, but the injection volume is larger than HPLC, generally 50 μL. The sample is first filled with a metering tube in a low-pressure state, and when the valve is rotated clockwise to another position, a sample of a fixed volume stored in the metering tube is sent to the separation system.

Second, the pneumatic injection valve
The pneumatic valve is powered by certain helium or nitrogen gas pressure. After the two-way four-way loading of the quantitative tube, sampling and injection are carried out, which effectively reduces the error caused by the different movements of the manual injection.

Third, automatic injection
The autosampler is automatically controlled by the chromatography workstation to perform a series of manipulations such as sampling, injection, and cleaning. The operator only needs to load the samples into the storage machine in sequence. The working steps of the disc type autosampler are as follows:

(1) The motor drives the storage tray to rotate, and the sample to be analyzed is placed directly below the sampling needle.
(2) The motor rotates forward, the screw moves the slider downward, inserts the sampling needle into the sample plastic cover, the slider continues to move down, pushes the bottle cap into the bottle, and the sample flows through the pipe under the cap extrusion Sample valve quantitative tube, complete the sampling action.
(3) The injection valve is switched to complete the injection.
(4) The motor is reversed, the screw moves the slider up, and the sampling needle returns to the original position.
The automated injection can achieve a wide range of sample injections.

The material of the nylon membrane filter is aliphatic nylon. It has good hydrophilicity, the appropriate concentration of acid and alkali resistant, and applies not only acid and alkaline aqueous solution, but also suitable for organic solvent, such as alcohols, hydrocarbon, ethers, esters, ketones, benzene and benzene homologs, dimethylformamide and dimethyl sulfoxide.

The nylon membrane filters are one of the most widely applicable scopes microporous membrane filters. (belonging to the terminal filtration membrane), the aperture of which is 0.22 – 5.0 um and the size of which is φ400 –φ25mm.

Application fields of the nylon membrane filters

1. Terminal filtration of API, medicinal solvent, injection water, injection and infusion solution, etc.
2. Terminal filtration of high-purity water, mineral water, fruit juice, soft drinks, grape wine, liquor, beer, and dairy products.
3. Plasma filtration.
4. For the folding filter element.

Features of the nylon membrane filters

1. Hydrophilic, partially resistant organic, solvent, not resistant to strong acids. Protein binding ability is higher, so it is not suitable for protein recycling.
2. Matters needing attention when using the nylon membrane filter
3. The filtrate must be prefiltered when there are too many particles or bacteria in it.

Hawach Scientific co., Ltd. provides with high performance. PES uniform pore size distribution enables the filter elements to have excellent bacterial interception ability. PES has been widely used in medicine, biology, beverage and drinking water due to its good chemical compatibility and hydrophilicity. PES pleated filter cartridge in line with GMP standards. PES strictly controls the production environment to ensure the quality and cleanliness of the filter elements.

Products feature

1. Uniform pore size distribution has an excellent ability to trap bacteria
2. The material complies with FDA standard
3. Adopt hot welding technology
4. Integrity testing

Application

1. Antibacterial filtration in the pharmaceutical and biological industry
2. Filtration of drinking water, beverages, and alcohol
3. Filtration of high purity water and deionized water
4. Purification and filtration of chemical raw materials
5. prefiltering

Specification data

Diameter: 5/10/20/30/40 inch
Pore size: 0.2-5.0 um
Sterilize:
Online steam sterilization, (SIP):121℃,30min
High temperature and high-pressure sterilization, 121℃,30min
Biosecurity:
Endotoxin: <0.25EU/mL (10inch)
Dissolution content: ≤25mg (10inch)
 
 

Flash chromatographic column, also called rapid chromatographic column(rapid column crossing, which means gradient elution, decompression or pressurization of the column), medium pressure chromatographic column(for example, rapid elution is achieved by pressurizing with nitrogen and passing the column with a suitable expanding agent), is the basic tool for separation and purification in the laboratory.

Applications of Flash Column

Flash technology, developed in 1978 to purify organic compounds, is a fast and inexpensive technology compared to conventional column chromatography. Now, Flash separation and purification technology are widely used in drug research and development, sample purification and natural product purification and other applications. Flash is one of the chromatographic separation and purification tools that cannot be replaced by the current preparative HPLC due to its low cost, simple and fast features.

Features of Flash Column

The elution speed of flash column can be controlled in four ways: one is to extend the filled column of elution fluid; The other is to control the tap; The third is to increase the pressure, such as by argon, nitrogen, air and other compressed air; The fourth is to increase the power so as to speed up the flow rate of the mobile phase through the pump.

Flash chromatographic column, also called rapid chromatographic column(rapid column crossing, which means gradient elution, decompression or pressurization of the column), medium pressure chromatographic column(for example, rapid elution is achieved by pressurizing with nitrogen and passing the column with a suitable expanding agent), is the basic tool for separation and purification in the laboratory.

Applications of Flash Column

Flash technology, developed in 1978 to purify organic compounds, is a fast and inexpensive technology compared to conventional column chromatography. Now, Flash separation and purification technology are widely used in drug research and development, sample purification and natural product purification and other applications. Flash is one of the chromatographic separation and purification tools that cannot be replaced by the current preparative HPLC due to its low cost, simple and fast features.

Features of Flash Column

The elution speed of flash column can be controlled in four ways: one is to extend the filled column of elution fluid; The other is to control the tap; The third is to increase the pressure, such as by argon, nitrogen, air and other compressed air; The fourth is to increase the power so as to speed up the flow rate of the mobile phase through the pump.

With different range of material manufacturing and capacity options, sample vials are usually used for collecting, storing, and transporting samples in the lab. You can find non-sterile or sterile vials in the color of amber or clear transparencies for a better view.

Hawach glass sample vials have a variety of sizes in clear or amber glass. For superior chemical resistance, clear vials are made of low extractable borosilicate glass. For protecting light-sensitive products, amber vials are made from borosilicate glass.

Three different types of sample vials are available: screw top, snap top and crimp top. It’s convenient that both snap vials and crimp vials can fit with either snap or crimp caps. And Snap caps can easily be applied and removed by hands. To ensure seamless operation with your autosampler, the crimp cap sample vial provides a bigger target area for improved autosampler needle accuracy.

And we guarantee that all of our vials, septa, and caps can work with the autosampler perfectly.
 
 
 

We can always hear such a conversation between those researchers.
“Hey, buddy, what is your purity degree of the end products today?”
“Damn it. Such a low degree that I cannot even use for the next step. Any better methods for clarifying raw materials?”

Then there comes Hawach syringe filter, a gospel for those scientific workers.

Syringe filter use: Filter chemical turbid solution samples, most commonly used in chemical HPLC-MS/GC-MS analysis of liquid and gas dedusting, sterilization filtration, biological sample preparation, tissue culture media, microbial media, buffer solutions, etc. Remove impurities and so on.

Think about it, why should the solvent and sample be filtered?

Firstly, solvent and sample filtration are very important, it will protect the column and instrument, and eliminate the impact of pollution on the analysis results.
Secondly, the packing particles are very thin, the column lumen is small, and the small particles in the solvent and sample make the column and capillary easy.
Thirdly, solvents and fine particles in the sample increase clogging and wear of the injection valve and the sapphire piston rod in the pump head.

Vacuum filtrations are based on the principle that oil and water vaporization temperature is different (water vaporization temperature is lower than oil vaporization temperature) under the same pressure.

Vacuum filtrations are a kind of paper filter equipment with the features of a high degree of automation and high precision, filter precision up to 10 microns.

Application of vacuum filtration – a vacuum oil filter

It relates to a continuous filtration operation for dewatering sludge, which is generally completed in a cylindrical rotary filter. The filter media can be natural fabric, synthetic fiber products or wire mesh. Usually, in order to make the vacuum oil filter to achieve good processing capacity, it is necessary to adjust the wet sludge.

Matters needing the attention of vacuum filtration

Before any maintenance or overhaul of the vacuum filtrations system, the pressure in the system must be released and the power cut off! High pressure can lead to heavy casualties!

When vacuum filtration system is working, it is not allowed to be close to or step on the scraper, or enter the box, which is controlled by the program time and may start suddenly, if involved, it may seriously damage personal safety.

When using filter paper, we should pay attention to the fact that when the filter paper is not displayed on the paper box of the filter paper, the precipitation should be paid attention to when using the quantitative and qualitative analysis filter papers.

(1) Natural filtration is generally used to separate liquids and solids by utilizing the filter paper body and the ability to intercept solid particles; Natural filtration is generally used to separate liquid from solid by using the ability of filter paper body and solid particle interception.

Because the mechanical strength and toughness of filter paper are relatively small, filter paper should be filtered as little as possible by suction method. If filtering speed must be accelerated, in order to prevent filtering failure, 2-3 layers of filter papers can be stacked in the funnel according to the suction force when air pump filters. When air suction is used, a dense filter cloth is first laid on the funnel and then filter paper is placed on it.

(2) Filter paper should not be dissolved in concentrated sulphuric acid or nitric acid.

(3)The qualitative analysis filter paper is mainly used as a carrier in paper chromatography. There are two kinds of filter paper, No. 1 and No. 3, for qualitative separation and chromatographic analysis of the substances to be measured. Each kind of filter paper can be divided into three kinds: fast, medium and slow.

Today, we’re going to show you how to clean a bottle-top dispenser. Before we get it started, let’s prepare a bottle of neutralization liquid, a bottle of distilled water, a bottle of the ethanol-glycerol mixture, a soft brush and a pipe cleaner.

Now, let’s follow the steps below.

Step 1: Attach the bottle-top dispenser to the neutralization liquid bottle to rinse the device with neutralization liquid.

Step 2: Attach the product to the distilled water bottle and rinse the device with distilled water.

Step 3: Detach the product, unscrew the piston mount and clean the piston and cylinder with the brush. Apart from this, you could also use the pipe cleaner to clean the tubes.

Step 4: Rinse the product with distilled water after reassembling the device.

Step 5: Rinse it with an ethanol-glycerol solution, the mixture of reagent grade non-denatured 99% ethanol and 1% glycerol.

Step 6: Use the delivery box to pack the bottle-top dispenser for long-term storage. The device dries fast even when it’s packed in a box.

Glass fiber extraction thimbles can be used to collect harmful substances such as smoke, dust, acid mist and so on. It is widely used at home and abroad. It has excellent performance in high-temperature resistance, low weight loss, high efficiency, and high strength. Just because of the popularization and application about it, the efficiency of smoke and dust detection at home has been greatly improved.

Due to the characteristics of glass fiber, the following points should be noticed when using this product:

1. Before being used, the adaption of glass fiber extraction thimbles with its sampler must be checked carefully. As you install or remove the extraction thimbles, the fracture in the rim of the extraction thimbles should be avoided.

2. The glass fiber extraction thimbles cannot be used as you see the defects such as the cap, crack or the irregular of itself. Sampling failure caused by air blowing should be avoided.

3. In order to achieve sufficient strength of glass fiber, the extraction thimble should be used under the required temperature all the time. When heated to high temperature, glass fiber can remain high strength, but it will reduce rapidly when chilled. It was reported that the strength of the fibers remained only 35% when it was chilled after heating it to 510℃.

QuEChERS is widely used in many areas, in the case that the targeting recovery rate satisfies the need, and also the matrix background of removing impurities meets detection, it can be applied to purify stuff such as residues of food and veterinary, additives, plasticizers.

However, currently, QuEChERS is mainly used in detecting agricultural residues, so followings are applications in the detection of pesticide residues.

Oversea Pesticide Residue Monitoring

Foreign countries apply the technique extracting and purifying samples not only for fruits and vegetables, but also for various animal foods such as chicken, tilapia, and other high-sugar contained and complexly processed foods such as honey, biscuits, and chocolate.

Additionally, featuring good extraction effect, high fidelity and thorough purification, the skill targets numerous testing substances not only for pesticides, and the detection instruments are not constrained to regular gas-liquid chromatography.

Domestic Pesticide Residue Monitoring

During these years, due to the continued flourishing of technology, the application of QuEChERS technology in China has expended out of traditional agricultural products (fruits, vegetables, and cereals), and scientists have carried out to extract cereal samples with low water content.

When selecting the customer, it is recommended to first confirm the vacuum and pumping speed required for the experiment, or you can choose according to the application. The main uses of Standard Diaphragm Vacuum Pumps include the following:

1. Vacuum drying oven: It is suitable for vacuum drying oven with volume below 50 liters. The standard vacuum gauge is easy to observe the vacuum during use. The regulating valve can be easily released after pumping. Compared with the general oil pump and dry box, the most significant advantage is that there is no problem with oil backflow, oil change, and oil mist pollution.

2. Vacuum filtration: Compared with general oil-free piston pumps and diaphragm pumps, Standard Diaphragm Vacuum Pumps has the advantage of the higher vacuum, which can significantly increase the filtration speed when actually used in suction filtration. Especially for some customers with high particle content, viscous, the slow pumping rate of the ordinary suction pump, and hope to increase filtration speed and work efficiency, it is an excellent choice.

3. Air sampling: used to collect gas and can be discharged from the exhaust port of the tail to collect the gas to be sampled.

Pipetting methods for pipettes are divided into two types, namely, forward pipetting and reverse pipetting.

1. Forward pipetting

This technology uses a blow-out function to ensure complete transfer of liquid. Press the pipette button to stop. Put the suction nozzle into the liquid surface 2-3mm, gently release the button to return to the origin. Carefully lift the applicator and dock on the container wall to remove excess liquid.

Press the button to the stop point and the liquid is discharged. Hold the button for a while and continue to press the button to the second stop point (ie, blow out). This step will empty the nozzle to ensure accurate liquid transfer. Release the button and return to the origin. If you need to change the nozzle, continue to pipette.

2. Reverse pipetting

Using this technique, more than the set range of liquid will be inhaled, and the pipetting does not require a blowout function so that excess liquid remains in the pipette.

This technique is recommended when transferring highly viscous liquids, bioactive liquids, easily foaming liquids or very small amounts of liquid. Press the pipette button to the second stop point, immerse the nozzle at 2-3mm below the liquid level, and gently release the button to return to the origin.

Carefully lift the applicator and dock on the container wall to remove excess liquid. Tap the button to the stop point, exit the set range, and continue to hold down the button, the liquid will remain in the pipette without being transferred. The excess liquid is discarded with the suction nozzle or returned to the original container.

Product Highlights

Generally, SPE products are focused more on impurity dissolution and adsorbent. For its low impurity dissolution ability, due to all medical grade materials of PP and PE, SPE features resistance of corrosion and low content of impurities.

In addition, SPE’ s superior purification function totally attributes to imported adsorbents.

Test Reports

According to the quality inspection report, the SPE passed COA, which is the first certification of a product and customers are assessed to the report under appropriate circumstances.

As for the application example test report, there are loads of statistics supporting that SPE is widely used in labs of areas.

Typical Application Analysis
*HLB and C18 are universal columns so that all kinds of projects could import them.
*MCX, Florisil, and C18 have the common specification of 6ml.
HLB and C18 provide the regular model of 60mg/3ml.

In order to extend the life of the column, we need to pay attention to the following points when using the HPLC column.

1. Avoid sudden changes in pressure and temperature and any mechanical shock. Sudden changes in temperature or dropping the column from a height will affect the filling condition in the HPLC columns; a sudden increase or decrease in column pressure will also impede the packing in the column, so it should be slowed when adjusting the flow rate when the valve is injected. The rotation of the valve cannot be too slow (as described above).

2. The composition of the solvent should be gradually changed, especially in reversed-phase chromatography, and should not be changed directly from organic solvent to all water, and vice versa.

3. Generally speaking, the HPLC columns cannot be backflushed. Only when the producer indicates that the column can be backflushed, the impurities remaining in the column head can be backflushed. Otherwise, the recoil will quickly reduce the efficiency of the column.

4. Choose to use a suitable mobile phase (especially pH) to avoid damage to the stationary phase. Sometimes a pre-column can be connected in front of the injector. When the analytical column is bonded to silica gel, the pre-column is silica gel, so that the mobile phase can be “saturated” by the silica gel before entering the analytical column to avoid dissolution of the silica matrix in the analytical column.

5. Avoid injecting samples with complex matrices, especially biological samples, directly into the HPLC columns. Pretreatment of the sample is required or a guard column is connected between the injector and the column. The guard column is typically a short column filled with a similar stationary phase. The guard column can and should be replaced frequently.

6. Rinse the column with a strong solvent often to remove impurities that remain in the column. When cleaning, the displacement of the mobile phase in the flow path system should be gradually transitioned with a solvent that is miscible. The volume of each mobile phase should be about 20 times the volume of the column, that is, 50 to 75 ml for routine analysis.

PTFE stands for Poly Tetra Fluoroethylene. People generally call it non-sticking lining or easy-cleaning material. The material of PTFE has the characteristics of antiacid and antisolvent, which means it is hardly insoluble in all solvents. And PTFE is heat-resistant and with low friction coefficients. People always not only use it for lubricating but also regard it as the ideal coating material for the lining of water pipes.

PTFE membrane is a kind of material named ultra-fine fiber glass coated with PTFE resins. Its durability、fireproofing and antifouling property are all outstanding. The PTFE membranes are usually white, have high transmittance and the ability to maintain its performance for more than 25 years.

PVDF is the abbreviation for Polyvinylidene Fluoride. PVDF membrane is from PVC membrane that is coated with PVDF resins on it, which is better than PVC membrane in durability. PVDF membrane is a kind of solid-phase carriers for the western blot in common use. It is hydrophobic.

The smaller the aperture of the PVDF membrane is, the firmer the PVDF membrane is. There is an interesting phenomenon that PVDF membranes are popular than PTFE membranes in the northern territory. Maybe the reason is that the glass transition temperature of PVDF membranes is close to 40 degrees below zero, it is better in low-temperature resistance.

The fold-type inlet filter membrane is adapted for the filtration of large surface area and suitable for the filtration of large volume solution. The filter, which is made of polypropylene, is free of adhesives and other chemicals and is not meant to contaminate the sample. Hydrophobic polytetrafluoroethylene (PTFE) filter membrane is used for solvent and corrosive solution filtration.

If you want to learn more about PTFE filter capsule, you can visit our website.

Products feature
1.High flow rate, low dissolution, low-pressure difference
2.Disposable design, safe and convenient
3.Clean environment production
4.Low retention volume

Application

1.Gas sterilization filtration
2.Filtration of water and chemical reagents
3.Ink filter
4.Corrosive liquid
5.Photoresist filtration in LOD production
6.Air and gas filtration
7.Optical storage industry CD-R, DVD-R fuel in the production of filtration
8.The chemical industry, bio-pharmaceuticals, laboratories and other solvents, pharmaceutical filtration

Specification data

Diameter : 3.2inch/82.4mm
Length : 81.5inch/207mm
In/out : Φ1inch/25.4mm
Filtration area: ≥ 2.2tf²/0.2m²
Maximum service temperature: 80℃

As an efficient and easy way to separate complex mixtures of compounds, chromatography provides increased resolution and the effective separation of complex peptide mixtures as well. Hawach flash columns adopt ultra-pure and high quality boned silica with multiple sorbents. They also have a wide range of size for different applications.

With reliable, consistent performance from automated precision packing, our flash columns have high flow rates for fast purification of target compounds. The sizes of the different column are available for purifying milligrams to several grams.

Fitting Luer lock end, Hawach products of the flash column are all made of medical grade PP cartridge which offers high compatibility, safety, and flexibility with free leakage, and medical PE grade frit which prevents media from leaking and allow mobile phase passes through.

With C18 flash columns, Silica Flash Columns and other bonded ones, multiple pore sizes and particle sizes are available for your application, easy connection to other instrument systems and manual setups, such as Biotage, Grace, Armen, Moritex, etc..

A sample vials cap (or gasket), made of paper, rubber, corkwood, metal, glass fiber or plastic polymer, is placed between the two planes to strengthen the seal and prevent fluid leakage. Machined surfaces cannot be perfect so use caps to fill in irregularities. Asbestos may be present in caps for specific applications.

The function of the sample vials cap

1. Prevent damage to objects caused by the use of spring pads in the process of removing screws.
2. Increase the contact area.
3. It can be used in some special situations.
4. Increase friction.

The choice of sample vials caps material mainly depends on the following three factors: temperature, pressure, and media. According to its material and structural characteristics, caps can be divided into non-metallic caps, metallic caps, metal-non-metallic composite caps, each category of which also can be subdivided into a number of types.

Sealing sample vials cap installation requirements

1. The sealing surface shall be cleaned.
2. When the sealing cap is pressed, it is best to use a torque wrench.
3. When installing the sealing caps, tighten nuts in sequence.
4. The pre-tightening force of the sealing cap shall not exceed the design specification.

A sample vials cap (or gasket), made of paper, rubber, corkwood, metal, glass fiber or plastic polymer, is placed between the two planes to strengthen the seal and prevent fluid leakage. Machined surfaces cannot be perfect so use caps to fill in irregularities. Asbestos may be present in caps for specific applications.

The function of the sample vials cap

1. Prevent damage to objects caused by the use of spring pads in the process of removing screws.
2. Increase the contact area.
3. It can be used in some special situations.
4. Increase friction.

The choice of sample vials caps material mainly depends on the following three factors: temperature, pressure, and media. According to its material and structural characteristics, caps can be divided into non-metallic caps, metallic caps, metal-non-metallic composite caps, each category of which also can be subdivided into a number of types.

Sealing sample vials cap installation requirements

1. The sealing surface shall be cleaned.
2. When the sealing cap is pressed, it is best to use a torque wrench.
3. When installing the sealing caps, tighten nuts in sequence.
4. The pre-tightening force of the sealing cap shall not exceed the design specification.

Syringe filter are filters for standard lab samples, providing a fast, convenient and reliable way to filter samples. It is widely used in colloid separation, microanalysis, gravimetric analysis, and aseptic test.

Syringe filter handle chromatographic samples without introducing other impurities into the process. The material of the membrane and shell structure is very important. Because of the precision of the chromatographic system and the accuracy of the result analysis, it is very important to filter the samples.

Application of syringe filters
1. Sample prefiltration;
2. Clarifying and removing particles;
3. Liquid and gas filtration.

Syringe filters have different filter membranes (PTFE, PES, nylon 6, nylon 66 and PVDF) selection and each filter membrane has different apertures.
Common syringe filters include edge filters and ultrasonic filters:

An edge filter: the disadvantage of the traditional filter is easy blasting. An edge filter is suitable for ventilation, gas purification, gas sterilization, and water resistance.

An ultrasonic filter: it adopts new ultrasonic welding technology and new double-layer membrane design, which can filter large particles in advance, especially suitable for filtering large particles and multi-impurity materials.

sample vials cap (or gasket), made of paper, rubber, corkwood, metal, glass fiber or plastic polymer, is placed between the two planes to strengthen the seal and prevent fluid leakage. Machined surfaces cannot be perfect so use caps to fill in irregularities. Asbestos may be present in caps for specific applications.

The function of the sample vials cap

1. Prevent damage to objects caused by the use of spring pads in the process of removing screws.
2. Increase the contact area.
3. It can be used in some special situations.
4. Increase friction.

The choice of sample vials caps material mainly depends on the following three factors: temperature, pressure, and media. According to its material and structural characteristics, caps can be divided into non-metallic caps, metallic caps, metal-non-metallic composite caps, each category of which also can be subdivided into a number of types.

Sealing sample vials cap installation requirements

1. The sealing surface shall be cleaned.
2. When the sealing cap is pressed, it is best to use a torque wrench.
3. When installing the sealing caps, tighten nuts in sequence.
4. The pre-tightening force of the sealing cap shall not exceed the design specification.
 
 
 

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C18 HPLC columns are the reversed phase columns, high purity silica gel skeleton, single function high-density bonding, excellent peak shape, extremely high stability, suitable for the separation and analysis of amphoteric and acidic compounds.

Application of C18 HPLC column

1. Good separation of neutral, acidic, amphoteric and partial alkaline compounds;
2. Especially suitable for the analysis of acidic and amphoteric small molecular compounds;
3. Can be used to maintain the stability of the compound;
4. Can be used to change the separation selectivity.

The installation and use of C18 HPLC columns

Rotate the column heads at both ends of the column and connect them to the instrument according to the direction of fluid flow on the label of the column. When the column is not in use, screw on both ends of the column.

Sample and mobile phase

To avoid blockage of C18 HPLC columns, the sample and mobile phase are filtered by a filter membrane before use. The mobile phase is a mixture of the organic phase and water phase, such as methanol-water, acetonitrile-water.

It is best to install a protective column to prevent impurities and protect C18 HPLC column.

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Filtration is one of the most widely used laboratory techniques we use in laboratories and elsewhere. Filter papers seems like a kind of magical paper that separates the solvent and solid. You might spend a long time finding the suitable filter paper for your experiment or project and want this process to be easier.

Here are some important parameters for you to refer to when you choose the filter paper:

1. What particle size does it hold on to? (This is known as particle retention.)
2. Will the filtered chemical be compatible with your solution? (This can affect the contamination of the sample as well.)
3. Will you be able to get the solid sample off the filter papers when you need to?
4. How much solid sample could the filter paper hold before it gets clogged up? (This is known as loading capacity.)
5. How quickly will the solution flow through the filter paper? (This is known as flow rate. It is quite related to the loading capacity.)
6. Will the filter papers break during filtration? (This is in some way measured as wet strength.)

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The bottle-top dispenser is an instrument for measuring solutions accurately. Several dos and don’ts we must know before we using it in the experiments.
1. When installing the drain pipe and the liquid inlet pipe, we should let the mouth of the pipe insert into the valve straightly and tighten the nut in case of violent installation that causes the damage.
2. Whenever using the bottle-top dispenser, we should ensure that all the valves including the inlet one and the drain one are installed correctly and tightened in order to avoid the spatters caused by piston motion.
3. Do not let the drain pipe directly direct to the operators to ensure operation safety.
4. We should control the velocity of piston movements and make it slow and uniform. And at the same time, the liquid is flowing down the wall and received by the proper container.
5. Stop operating immediately as long as there exist any problems so as not to damage the instruments.
6.4-50℃ is the suitable temperature range for operating the bottle-top dispensers.
7. Do not let the organic reagents remain on the surface of the instruments. If it happened, we should clean it by water at once.

The extraction thimbles are located in the extractor body. They are used to extract certain components out of the sample of solid material, with the addition of sufficient and suitable solvent.

The extraction thimbles are usually manufactured in three sorts by different materials, the high purity cellulose, the pure borosilicate glass fiber, and the high purity quartz microfiber. We used them to achieve an efficient and reliable analysis in the lab.

The main features of the cellulose extraction thimble is high purity and the strong mechanical structure and retentiveness. They are widely used for extraction of polymers, environmental pollutants determination, etc.

The glass micro-fiber extraction thimbles are made from pure borosilicate fibers without any kind of binders used in the manufacturing process. It is the best choice of extraction thimble if the solvents are not acceptable with the cellulose ones.

Made from the pure quartz microfiber, the quartz microfiber thimbles are able to stand high temperatures, sometimes up to 900°C. They also meet the purity requirements with their low heavy metal content. They are super suitable when extracting solvent and air sampling applications in the lab.

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Extraction is often susceptible to matrix interference. One analytical method is fine in this matrix but can become problematic in another matrix. If we encounter such a situation, how can we improve the QuEChERS method to overcome it?

For pesticide residues, most of the food samples do not exhibit matrix interference except for some dry and greased samples. However, for some complex samples such as tea, traditional Chinese medicine, spices, liver and citrus oil, regardless of the QuEChERS method we apply, there is always the adsorption of the substrate on the pesticide residue. This is related to the method itself.

When the matrix contains impurities similar in structure to the analyte, it is difficult to purify it by the sample pretreatment process. Of course, some means such as adjusting the extractant, adjusting the pH, adding salt, changing the volume ratio, adding water, adding adsorbent can be of some help.

For example, acidic herbicides like phenoxyalkanoic acids tend to form covalently bonded residues. Such legally used pesticides are quite typical and therefore must be released prior to liquid-liquid extraction. Usually, we can firstly perform alkaline hydrolysis for 30 minutes by adjusting the pH to 12, and then have it return to neutral for QuEChERS extraction.

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What is a vacuum pump? The vacuum pumps are a rotary variable displacement vacuum pump that must be used with a foreline pump. It has a large pumping speed over a wide pressure range and is insensitive to dust and water vapor in the extracted gas. It is widely used. Metallurgy, chemical, food, electronic coating, and other industries.

Vacuum pump features

(1) Large pumping speed over a wide range of pressures;
(2) The compression is relatively low, and the effect on hydrogen gas pumping is poor;
(3) There is no compression in the pump chamber, no exhaust valve.
(4) There is a gap between the rotor and between the rotor and the casing, no lubrication, and the friction loss is small, which can greatly reduce the driving power, thereby achieving a higher rotation speed;

At present, vacuum pumps have been widely used in metallurgy, chemical, food, electronic coating, and other industries. Therefore, the quality of the vacuum pump determines the development of our metallurgical, chemical and other industries, then we need to pay attention to some related matters when using the vacuum pump, and protect it to the maximum extent.

If the volatile organic solvent is distilled, the organic solvent is absorbed by the oil, which increases the vapor pressure, thereby reducing the evacuation efficiency. If it is water vapor, the oil becomes an emulsion and the vacuum pump is pumped.

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1. Capacity setting
For the adjustable pipette, it is usually operated in the range of 10% to 100%. The optimal pipetting capacity is in the range of 35% to 100%. At this time, it is less affected by the operation technique and can better protect the pipetting. Accuracy and precision. For example, to remove 600 uL of liquid, it is best to choose a 100 to 1000 uL adjustable pipette instead of 500 to 5000 uL.

2. Install the tip
Installation method: Insert the lower end of the pipette vertically into the tip, turn it left and right, and tighten it.

Be careful not to use excessive force, otherwise, the internal components will be loose, and even the knob of the adjustment scale will be stuck or the pipette sleeve will be bent.

3. Rinse the tip
When an organic solvent or a highly volatile liquid is removed, a volatile gas forms a negative pressure in the sleeve chamber, causing leakage. Rinse the pipette tip 4 to 6 times to make the gas in the sleeve room saturated, and the negative pressure disappears automatically, which can effectively prevent liquid leakage. However, do not rinse the tip when the sample temperature is very high or low.

4. Aspirate
There are two ways to aspirate: positive aspiration, reverse aspiration.
Positive aspiration refers to the normal method of aspiration. Press the button to the first step to release the solution and release the button. Press the first gear first, then press most of the liquid, then press the second gear to discharge the remaining liquid.

Reverse aspiration refers to pressing the button directly to the second gear and then releasing it so that more liquid will be inhaled. Just press the first gear when the liquid is discharged. The multi-inhalation liquid can compensate for the surface adsorption inside the tip. The reverse aspiration is generally used in combination with the pre-flushing and aspirating method and is suitable for viscous liquids, volatile liquids and small volume pipetting.

5. Draining
There are three ways of draining: draining along the inner wall, draining above the liquid level, and draining below the liquid level. The usual “draining along the inner wall” steps can be seen below:

(1) Stick the tip of the nozzle to the inner wall of the container and keep it inclined from 10° to 40°, and smoothly press the button to the first gear. After a slight stop, press the second gear to discharge the remaining liquid; when discharging dense or viscous liquid, stay The time is a little longer.
(2) Press the button and lift the pipette to lift the tip of the container out of the container wall.
(3) Release the button.

6. Remove the tip
The tip can be removed by pressing the tip ejector with a little force. If the tip is installed too tightly, it can be removed by hand. Discard the tip into a suitable waste collector.

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Compared to the classic liquid extraction, SPE has its own obvious advantages. To be more specific, it could reduce solvent consumption and sample cost. SPE is also time-saving which has the potential for automation. Moreover, the consistency is high for specific sample handling. Due to the wide-ranged adsorbents which have different adsorption mechanisms. In order to optimize the extraction, solid phase and chromatographic condition could be changed and adjusted.

The involved steps in the complete SPE procedure. As a matter of fact, the steps shown below could be omitted in many applications so that it could be described as the general example and the procedure could also be simplified. In order to visualize the separation, the presenting procedure uses the samples with dye.

Actually, most of the samples contain colorless components, which could only be found in the collecting fractions by some detectors and tests. The information below should be as considered as guiding principles when developing your own process or revising the process published in the literature, which specifically contains the sample preprocessing, adjustment of the cartridge, sample loading, and fraction delusion.
 
 

Stationary Phase & Mobile Phase

The stationary phase is used to separate the substances, which is packed into HPLC Column directly; Mobile phase is the carrier, which carries the substances into the stationary phase and goes through the stationary phase.

It is gas in the vapor phase, and it is liquid in the liquid phase. Both are called a mobile phase.

Normal & Reversed Phase

While the polarity of stationary phase is greater than that of the mobile phase, it can be called normal phase chromatography; Oppositely, while the polarity of stationary phase is less than that of the mobile phase, it can be called reverse phase chromatography.

The stationary phases used in normal phase chromatography are usually silica gel (Silica), and the other bonded phase adsorbent with polar functional groups, such as (NH2, APS) and cyano group (CN, CPS). The HPLC Column made of this kind of absorbent is called normal phase HPLC Column; the absorbent used in reverse chromatography is usually based on silica gel, and the surface bonding phase has relatively weak functional groups. The commonly used reverse absorbent are C18 (ODS), C8 (MOS), C4 (Butyl), C6H5 (Phenyl) and so on. The HPLC Column made of this kind of absorbent is called reversed phase HPLC column.

Low polar mobile phases such as n-hexane can be used in normal phase chromatography and strong polar mobile phases such as methanol or water can be used in reverse phase chromatography.

Difference in Application

In the normal chromatography, the stationary phase is polar and the mobile phase is non-polar, which is suitable for separating strong polar substances, and the elution sequence is from weak to strong; the stationary phase of In the reversed phase, the stationary phase is non-polar and the mobile phase is polar, which is suitable for separating weak polar substances, and the elution sequence is from strong to weak.

Generally, the reversed chromatography is often used, and the normal chromatography is only used under special conditions, for example, the sample is sensitive for the water.

The function of filter membrane material is determined by its microstructure. Knowing and understanding the microstructure of the material of the membrane can help us explain the technical parameters of the filter membrane from the mechanism and finally choose the right product. Below are the microstructure diagrams of the six common membranes:
Careful observation of the microscopic,the results shows that the microporous of GF membrane is composed of numbers of elongated fibers, which determines its relatively low density. GF membranes can accommodate many particles both on the surface and inside the membrane.

Relatively speaking, the structure of PES, MCE, PTFE, NY, PVDF is a regular network system and has a relatively dense interior except for the large gap of the surface. So the particles are mainly retained at the surface of the PES, MCE, PTFE, NY, PVDF membranes.

In general, GF has a strong capacity of holding dirt, but the absolute interception accuracy is not as high as that of the regular network system. Therefore, it is commonly used in coarse filtration and pre-filtration and preferentially retains large particles to protect the latter membrane from being clogged.

It is worth mentioning that the PP filter membranes and the GF structure are similar in characteristics, and are mainly used for pre-filtration to prevent clogging.

The Capsule type filter is also called the integral type filter, uses the folding type import filter membrane, the filtration surface area is big, suits the bigger volume solution filtration. The filter, which is made of polypropylene, is free of adhesives and other chemicals and is not meant to contaminate the sample.PES microporous membrane has good chemical compatibility and biosafety. High retention, low extraction, and very low protein adsorption.More detail information from info@hawach.com
Products feature
1. It has complete biological safety and no toxicity
2. 100% integrity test
3. Produced in a clean environment and maintained in a clean state
4. You can choose from a variety of apertures
Application
1. Tissue culture medium filtration
2. Filtering of medicines, cosmetics, food and beverage
3. Remove bacteria or submicron particles
4. Purification of water, chemicals and reagents
Specification data
Material: PES
Support & housing: PP
Sealing technology: Thermal fusion welding (without binder)
Diameter: 3.2inch/82.4mm
Length: 81.5inch/207mm
In/out: Φ1inch/25.4mm quick interface
Drain/exhaust: Φ0.2inch/5mm intubation
Filtration area: ≥ 2.2tf²/0.2m²
Maximum service temperature: 80℃
Positive pressure difference: liquid: 3.5bar@23℃,3.0bar@60℃
Gas: 3.0bar@23℃,2.5bar@60℃
Sterilize: can be affected by three consecutive 121 ℃ high pressure steam sterilization, sterilization online is not recommended.

The working theory of flash column

Flash evaporation is a process in which saturated water at high pressure enters a relatively low-pressure vessel and becomes part of the saturated water vapor and saturated water at the pressure of the vessel due to a sudden drop in pressure. In the chemical production process, the flash column can realize rough gas-liquid separation of materials. The flash column can be roughly separated before entering the atmospheric furnace, which can reduce the load of the atmospheric furnace.

Classification of Flash column:
Hawach’s flash column has three main series as follows:
StarFlash Series: This series only has silica gel columns. It can be divided into two categories: standard and advanced. The high-grade silica gel flash column has higher purity and better quality.

PureFlash Series: This series corresponds to silica gel construction and phase column, C18 (spherical import and irregular homemade), C4, C8, NH2,
CN, HILIC, alumina, etc. They have all imported fillers, corresponding to the high-end market.
DepuFlash Series: This series corresponds to silica gel construction and phase columns, C18 (spherical and irregular), C8, NH2, CN, Phenyl, SAX, SCX, Diol. They are all domestic fillers, corresponding to the low-end market.

sample vials cap (or gasket), made of paper, rubber, corkwood, metal, glass fiber or plastic polymer, is placed between the two planes to strengthen the seal and prevent fluid leakage. Machined surfaces cannot be perfect so use caps to fill in irregularities. Asbestos may be present in caps for specific applications.

The function of the sample vials cap

1. Prevent damage to objects caused by the use of spring pads in the process of removing screws.
2. Increase the contact area.
3. It can be used in some special situations.
4. Increase friction.

The choice of sample vials caps material mainly depends on the following three factors: temperature, pressure, and media. According to its material and structural characteristics, caps can be divided into non-metallic caps, metallic caps, metal-non-metallic composite caps, each category of which also can be subdivided into a number of types.

Sealing sample vials cap installation requirements

1. The sealing surface shall be cleaned.
2. When the sealing cap is pressed, it is best to use a torque wrench.
3. When installing the sealing caps, tighten nuts in sequence.
4. The pre-tightening force of the sealing cap shall not exceed the design specification.

 

This is a useful weapon for experimental analysts to filter micro-samples quickly and effectively, such as sample pre-filtration, clarification, and filtration of particles, liquids, and gases sterilizing, etc.

The structure of Hawach syringe filter
The structure of Hawach syringe filter consists of housing and membrane. As the name suggests, it is the combination of syringe and filter and connects to the front end of the syringe. The syringe is an external manifestation—housing, essentially a filter—membrane. Its main function is to separate the mixed two phases. The housing and membrane can be made of many different materials. Membrane, in the industry, the most common materials are Nylon, PVDF, PTFE, MCE, CA, Glass Fiber, PP, PES.

The choice of analysts
To start from the perspective of the most user demand– experimental analysts have a natural obsession with fast and accurate. Keep filtering or aseptic filtration with hundreds of cleaning the filter and replacing membranes will destroy all–it must be wise to choose syringe filter. It is essential for sample preparation, determination, even environmental detection, fuel analysis, and other directions.

Precautions for use
Avoid the introduction of other impurities into the filtrate during the filtration process. Select the appropriate filter membrane to handle samples of different properties.

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A GF filter membrane is made of 100% borosilicate glass fiber, with capillarity fiber structure, which can absorb more water than the same fiber filter paper, with fast flow rate, high bearing capacity, high-temperature resistance, and can very well retain fine particles.

A GF filter membrane has the characteristics of non-hygroscopicity and biological inertness and is resistant to chemical corrosion of most solvents and reagents except hydrofluoric acid and high concentration of the acid-base solution.

Application
1. Used for daily air pollution monitoring;
2. The collection of high-efficiency fine particles;
3. Used for water pollution analysis;
4. Dust collection in the air.

A GF filter membrane without binder is usually used for filtering fine particles, which is divided into six grades: A, B, C, D, F, and H.

Binder can enhance the mechanical strength of a GF filter membrane that is mainly used to filter coarse particles (such as macromolecular substances and dust). In order to avoid chemical reactions with the filtered substances, the glass fiber with the inorganic binder is selected when filtering organic substances and the glass fiber with an organic binder is selected when filtering inorganic substances. The most common grades are 6, 8, 9, and 10.

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Hawach Scientific is a professional manufacturer for filter paper, right now we have Glass Fiber Filter paper GF/C which can replace Whatman GF/C, the quality is equivalent and the price is very competitive.

Our GF/C filter paper without binder, we have 0.7um and 1.2um for choose, the size from 13mm to 250mm, accept customized size and OEM.

In the past our packing is 100pcs/pk for 25mm, right now we have new packing and the amount for one pack is 50pcs/pk, here is the packing photo for old type and new type:
 
 
 
Any question or help for GF/C, please don’t hesitate to contact us.

Thank you and have a nice day.

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For safe, accurate and accurate dispensing of bases, saline solutions, acids, and some organic solvents, bottle-top dispensers are the perfect tool in the lab. Scientists set them directly on most solvent and reagent bottles for faster and easier dispensation.

Bottle-top dispenser can dispense most of the lab reagents, such as acids, bases, saline solutions. They can dispense many organic solvents as well, such as HCl and HNO3, trifluoroacetic acid (TFA), tetrahydrofuran (THF), and peroxides.

Bottle-top dispensers can deliver accurate, precise volumes while dispensing, And on the advanced digital models, we can find accurate volume settings through a digital display.

Including safety features to reduce the risk of injury from inadvertent dispensing and splashes in the lab, bottle-top dispenser can be attached on reagent bottles to reduce poured reagent transfers. In this way, the laboratory safety is increased. At the same time, the recirculation valve system of the bottle-top dispensers improves conservation and safety of reagent.

The feature of perfect wear and damage resist makes the dispensation always go smooth. They can be disassembled and washed easily as while. With the bottle-top dispenser on your hand, reliable dispensing is at your fingers.

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The glass fiber extraction thimble is made of ultra-fine glass fiber and is used for various applications. It’s a high-efficiency filter device for collecting harmful substances such as soot, acid mist, and beryllium substitute. It has the advantages of high-temperature resistance, small weight loss, high efficiency, and good strength.

When you use a glass fiber extraction thimble, please note the following advice:

1. Check all parts of the sampling head before using the device to make sure they match one another and the gap is suitable.

2. When the device is loaded or unloaded, make sure it’s not subjected to the force such as tearing force or shearing to protect it from breaking.

3. If the device is found to have voids, cracks, and uneven thickness, it cannot be used as it might cause sampling failure due to airflow blow.

4. Use the device within the specified temperature range to ensure the device operates at sufficient strength. It has been reported that the strength of the glass fiber begins to decrease when it’s heated to above 200°C and then cooled.

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QuEChERS, composed with Quick, Easy, Cheap, Effective, Rugged and Safe, is a latest developed sample pretreatment technology of detecting agricultural products, which was developed by one professor from the United States Department of Agriculture in 2003.

Principle

Its principle is similar to that of High-Performance Liquid Chromatography (HPLC) and Solid Phase Extraction (SPE). Both of them utilize the interaction between adsorbents and impurities of the matrix adsorbing impurities to remove impurities and realize purification.

General Steps

The steps of QuEChERS technology can be simply summarized as follows.

1. Crush samples
2. Extract and separate of acetonitrile of the single solvent
3. Add MgSO4 and other salts to remove water
4. Add ethylenediamine-N-propyl silane (PSA) or other adsorbents to remove impurities
5. Detect the supernatant

Advantages

The QuEChERS also has the following advantages. (three of the all are listed only)

1.High Recovery Rate
The recovery rate of a large number of polar and volatile pesticides is more than 85%;
2.High Accuracy and Precision
This can be modified by the internal standard method.
3.A Wide Range of Analyzable Pesticides
Including polar and non-polar pesticides, experts can apply this technology to acquire a higher recovery rate.

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When selecting the customer, it is recommended to first confirm the vacuum and pumping speed required for the experiment, or you can choose according to the application. The main uses of Standard Diaphragm Vacuum Pumps include the following:

1. Vacuum drying oven: It is suitable for vacuum drying oven with volume below 50 liters. The standard vacuum gauge is easy to observe the vacuum during use. The regulating valve can be easily released after pumping. Compared with the general oil pump and dry box, the most significant advantage is that there is no problem with oil backflow, oil change, and oil mist pollution.

2. Vacuum filtration: Compared with general oil-free piston pumps and diaphragm pumps, Standard Diaphragm Vacuum Pumps has the advantage of the higher vacuum, which can significantly increase the filtration speed when actually used in suction filtration. Especially for some customers with high particle content, viscous, the slow pumping rate of the ordinary suction pump, and hope to increase filtration speed and work efficiency, it is an excellent choice.

3. Air sampling: used to collect gas and can be discharged from the exhaust port of the tail to collect the gas to be sampled.

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In order to facilitate the observation of the condition of the sample in the tip during the pipetting process, many users will keep the pipette at an angle of 45 degrees or even closer to the horizontal angle during the pipetting process. But this is wrong again.

1. When removing a sample that approaches or reaches the maximum volume of the tip, the large angle of the pipette can easily cause the liquid to slip into the handle of the pipette, thereby contaminating or even corroding the piston of the pipette. Causing cross-contamination of the sample;

2. The large angle of the pipette tilt will also increase the contact surface of the outer wall of the tip with the liquid so that the liquid remaining on the outer wall when the tip leaves the liquid surface is more.

It is easy to follow the inside of the tip when draining The liquid leaves the tip together, which reduces the precision of the pipetting, and for these small amounts of liquid (for example, 2 ul and 10 ul) pipettes, the damage to the accuracy is likely to be fatal!

After selecting the type of SPE cartridges, we have to determine the specifications of the SPE cartridge.

The principle of selecting the SPE cartridge specification is to first ensure that the SPE cartridge packing has sufficient capacity to retain the target compound 100% on the column. On the other hand, the filler is not too much. The more filler, the greater the amount of solvent that is effective for the target compound to elute. Therefore, the SPE cartridge capacity must be considered when selecting the specifications for the SPE cartridge. Cartridge capacity refers to the mass of a compound that retains a compound with a primary force per unit mass. The capacity of the bonded silica cartridge is generally from 1% to 5%.

Take the SPE cartridges with 100 mg filler as an example. The maximum capacity is generally less than 5 mg. The cartridge capacity of the ion exchanger is about 0.5 to 1.5 meq/g. It is worth pointing out that because we are mostly a mixture, there are many interfering substances besides the target compound.

Therefore, when selecting the cartridge size, it is necessary to consider the target compound and the total amount of interference substances that may be adsorbed under the extraction conditions, and not only the target compound. Otherwise, even if the target compound does not exceed the cartridge capacity, the SPE cartridges retain some of the interfering substances while retaining the target compound.

Since the total amount of the two has exceeded the cartridge capacity, the result is that some of the target compounds cannot be retained. On the SPE cartridge. Therefore, for safety reasons, it is recommended that the cartridge capacity be better than twice the estimated target compound content.

The key to regenerating contaminated HPLC columns is to know the nature of the contaminants and to find the right solvent to remove. If contamination is caused by the accumulation of strongly retained materials during repeated injections, simple steps to remove these contaminants can often restore their chromatographic behavior.

Occasionally, after many operations, the column is rinsed with 90 to 100% solvent B (the stronger solvent in the dual solvent reversed phase system) to remove contaminants.

For example, the residual lipid in the column can be a nonaqueous solvent such as methanol, acetonitrile or tetrahydrofuran. If you are using a buffer system, do not switch directly to a strong solvent.

Sudden switching to a high concentration of organic solvent may cause buffering in the HPLC flow system, which can lead to larger problems such as plugging of the column, blockage of the pipe, pump Leakage, piston damage, or injection valve shaft failure.

The unbuffered mobile phase should be used first (i.e. the buffer should be replaced with water). Replace the strong solvent after rinsing 5 to 10 volumes.

Usually, there are two essential properties that end users are the most—extractability of the impurities and advantages of microporous polymer membranes.

Extractability of The Impurities

Scientific laboratories mostly apply the membrane product to filter samples, mobile phase, and chemical solvents. Hence, once the filter membranes itself dissolves some impurities during the experiment, the final results informed from customers would be affected seriously.

To conclude, products from Hawach Scientific Co., Ltd have lots of following merits.

First, all filter membranes are imported from Germany or the US so that there are proportioned materials and low contains of impurities. Second, the workshop where production is cut and packaged is highly clean.

Microporous Product Advantages

According to the Standard specification of ISO9001, the quality of Hawach Scientific Co., Ltd production is supervised rigidly and the stability keeps remarkable among article batch numbers.

Besides, with various options of disc filters and breadths, purchasers are able to choose their ideal goods. Similarly, the large majority of filter membranes materials are suitable to lab samples from areas of the world making sure that the filtering process goes orderly as it was expected.

The filter bag is made of porous staple non-woven fabrics or nylon woven nets and other materials which are heat sealed or vehicle sewed. The filter bag is the key part of the operation of the bag filter.
Characteristics of the filter bag
The filter bag is the most high-performance representative in the filter material industry. It is also the highest performance variety in all commonly used filter materials. It has reached a high level of filtration efficiency and accuracy.
Classification of the filter bag
1. According to the shape of the filter bag cross-section, it can be divided into a flat bag (trapezoidal and flat) and around bag (cylindrical).
2. According to the way of air in and out, it can be divided into two types: downwind, upwind, downwind and direct current (limited to flat bags).
3. According to the filtering mode of the filter bag, it can be divided into external and internal filtering modes.
4. According to the use environment of the filter bag and the temperature-resistant procedure, it can be divided into normal temperature, medium temperature, and high temperature.

The aim of flash column chromatography is to separate components from the mixture and purify it. Briefly, flash column chromatography allows samples to be separated through columns filled with gels.

Flash column chromatography has been widely used in organic chemistry since its inception. Although there are some guidelines translated inaccurately, some facts are still true.

Firstly, increasing the sample size will result in a lower resolution. The resolution of flash chromatography is medium-level compared with high-performance liquid chromatography. As a consequence, the increasing number of samples will aggravate the situation.

Secondly, the best velocity depends on the length and width of the flash column and the properties of the gel, which means how many plates are there available theoretically for the solution. The longer and narrower columns will provide more theoretical plates.

And thirdly, the resolution is also affected by the stationary phase. If the stationary phase or the gel arranged on the column is more homogeneous and has a smaller particle size, it provides better resolution.

Manipulating all these factors to optimize the purity or recovery of components can be quite complex because of their interaction. Therefore, it is necessary to calculate the settings used in flash column chromatography before starting any real experiments. The best settings of the flash column can be calculated with the data from TLC.

Sample vial, also known as sampling bottle, purification bottle, sterile bottle, clean bottle, filter bottles, etc., is essential for pollution detection. It is special equipment which is qualified for cleaning according to the international standard ISO3722 “Identification of Cleaning Method of Hydraulic Drive Sampling Vessel”.

Manufacturing Technology of Sample Vial

Taking the sample vial for particle counter as an example, the manufacturing process of the sample vial is as followed.

The special sample vial for particle counter is made by a set of technological processes, such as cleaning with the high precision ultrasonic cleaner, 1000-grade clean air shower, drying, and sealing. The cleanliness of the sample vial is NAS1638-1, which is a special sample vial for the liquid contamination test of the particle counter. The special sample vial for particle counter is suitable for sample collection, high cleanliness reagents, granular reference materials and standard samples for various liquid granularity tests.

Sample vial for particle counter is mainly used for the following three purposes:

(1) It is used to collect liquid samples for particle contamination test.
(2) It can be used to hold highly clean reagents.
(3) It is used for filling granular reference materials and standard samples.

This is a useful weapon for experimental analysts to filter micro-samples quickly and effectively, such as sample pre-filtration, clarification, and filtration of particles, liquids, and gases sterilizing, etc.

The structure of Hawach syringe filter
The structure of Hawach syringe filter consists of housing and membrane. As the name suggests, it is the combination of syringe and filter and connects to the front end of the syringe. The syringe is an external manifestation—housing, essentially a filter—membrane. Its main function is to separate the mixed two phases. The housing and membrane can be made of many different materials. Membrane, in the industry, the most common materials are Nylon, PVDF, PTFE, MCE, CA, Glass Fiber, PP, PES.

The choice of analysts
To start from the perspective of the most user demand– experimental analysts have a natural obsession with fast and accurate. Keep filtering or aseptic filtration with hundreds of cleaning the filter and replacing membranes will destroy all–it must be wise to choose syringe filter. It is essential for sample preparation, determination, even environmental detection, fuel analysis, and other directions.

Precautions for use
Avoid the introduction of other impurities into the filtrate during the filtration process. Select the appropriate filter membrane to handle samples of different properties.

In this article, we want to clarify the syringe filter. Each of the different syringe filters is applied to the specific product Which the various syringe filter is worth seeing more and what are the right steps and methods to have a try.

Classification by membrane

The filtration membrane plays a very important role. It can directly determine the filtration effect of the sample be separated, and the analyst can judge directly from the usage. So it is a good classification method – gas filtration/sterile ventilation, liquid filtration.

Gas filtration/sterile ventilation is recommended to choose active carbon, hydrophobic PTFE and hydrophobic PVDF; Liquid filtration is divided into three main forms, aqueous solution, mixed solvent, and the organic solvent.

•Aqueous solution: PES tissue culture media, nylon / MCE / PES / PP / hydrophobic PTFE for clarification/sterile filtration/HPLC;
•Nylon / PP / PTFE for mixed solvent;
•Organic solvent: nylon / hydrophobic PTFE for polar hydrophilic; PVDF / hydrophobic PTFE/PP for non-polar hydrophilic.

Classification by price localization

Three series of products are positioned according to the price.
FILTSTAR: import high-ranking level with sterilization and non-sterilization transparent membrane.
WINSTAR: comparatively lowly kind with non-transparent sterilization membrane.
PURSTAR: transparent membrane and less membrane material, the same style with Millipore.

1. Product No., for example BIO-1.

2. Pore size and flow rate, The bigger pore size, the quicker flow rate.
Fast: 60-100S/100ML @ 80-120μm
Medium: 100-160 S/100ML@30-50μm
Slow:160-200 S/100ML @ 1-3 μm

But filter paper is different from filter membrane, the pore size cannot be a certain value, these data only for your reference.

3. Ash content: Some filter papers need to be burned out during downstream analysis. Qualitative and quantitative filter papers are distinguished according to the ash value. Hawach Qualitative filter paper ash: <0.1%, Hawach quantitative filter paper <0.007%.

4. Basic weight:
Qualitative filter paper 80+/- 4 g.
Quantitative filter paper 97+/-7 g

5. Particle retention: 98% intercepted particle size, 11μm, 8μm, 2.0μm, Hawach offers more than 5 options.

6. Burst strength: a data to show the durable of the paper.
five options among 120 140,180,200 and 320 mm H2O

7. Dimensions: such as round, square, boat or folded, round diameter(mm) 70,90,10,125,150,180,240,270,300. Square size(mm): 60×60, 41×45.

More tips, just feel free to contact us!

Hawach bottle-top dispenser combines the latest liquid accurate dispensing technology, high-tech materials, and ergonomically designed advanced dispensers, which are simple, safe, reliable and highly accurate laboratory liquid handling equipment.

Bottle-top dispenser features

1. Fast volume setting, precise scale design
2. Smooth and precise piston sliding up and down, making operation convenient and comfortable
3. Drain tube helmet can avoid contact with reagents, even if it is equipped with gloves, it can be easily installed or removed.
4. Suitable for any reagent bottle in the laboratory
5. Transparent pipette for reagent bottles of various sizes
6. Has strong chemical resistance
7. Can be sterilized by high temperature
8. Cover a range of 0.5-50ml capacity
9. The convenient design ensures simple and economical cleaning and maintenance of the dispenser

As a routine laboratory liquid handling product, the bottle-top dispenser is widely used for liquid handling of various chemical reagents. Bottle-top dispensers may be used in conjunction with a variety of different instruments in the laboratory to meet a variety of needs.

The bottle-top dispenser cannot produce internal dissolved matter during liquid storage and operation, otherwise, it will interfere with trace element analysis, produce cytotoxin, interfere with optical properties, and affect the chromatographic analysis.

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Fitting most commercially available Soxhlet extractors, we offer a variety of selection of high-quality extraction. To achieve an efficient and reliable analysis in the lab, the extraction thimbles are used to extract certain components out of the sample of solid material.
The thimbles are manufactured in high purity cellulose fibers or high purity glass microfiber.

Made from 100% pure borosilicate glass, the high-purity glass microfiber thimbles are available for special demands in the lab. These kind of thimbles are totally free from binders and other chemical additives. And the temperature it can stand is up high to 500°C. The pure glass microfiber extraction thimbles can be used when solvents are not compatible with cellulose thimbles.

The glass microfiber extraction thimbles are perfectly designed for applications such as hot and acidic gases analysis, pesticide residues analysis, determination of oil/fat content of foods, and analysis of oil and grease in solid wastes.

With applications in the field of gravimetric methods for hot environments and acidic gasses, as while as the biochemical analysis, the glass microfiber thimbles are also used in pollution monitoring techniques.

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The average sample addition recovery rate of QuEChERS method is higher than 85%, with fewer impurities interfering with the detection of the target substance, a small amount of solvent, simple and fast operation, which will be the preferred pretreatment method for routine detection of pesticide residues in small laboratories around the world.

In addition to the QuEChERS method, currently commonly used methods for the pretreatment of agricultural residues in food include:

1. Solid phase extraction (SPE);
2. Solid phase microextraction (SPME);
3. Gel permeation chromatography (GPC);
4. Supercritical fluid extraction (SFE);
5. Matrix solid-phase dispersion extraction (MSPDE);
6. Accelerate solvent extraction (ASE).

Improvement

Some improvements to the QuEChERS method are intended to ensure the effective extraction of ph-sensitive compounds (such as phenoxycarboxylic acids), minimize the degradation of unstable compounds (such as alkaline or acidic unstable pesticides), and expand the range of food substrate types that can be used with QuEChERS method.

The application prospect

Hawach QuEChERS method can be applied to the extraction and purification of various molecular structures and polar pesticide residues. The method is simple, rapid, accurate and sensitive.

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Stainless Steel Filtration System Product Introduction

Hawach stainless steel filtration system is widely used in research units, inspection and quarantine institutions, quality monitoring institutions, natural mineral water industry, drinking water industry, the pharmaceutical industry, beverage industry and other sectors of the filter membrane method microbial detection, suspension solid detection, sample purification of the filtration equipment.

Vacuum pump forms a negative pressure environment. The liquid samples to be tested are filtered through the microporous filter membrane, and the microporous microorganisms or solids less than the filter membrane are separated for further detection and analysis.
Operation method

As applications in microbiological detection is: placed sterile microporous membrane filter in sterilization filtration system support mat, mount has sterilization filter cup, pour in the liquid sample to be detected, open the oil-free diaphragm vacuum pumps, open the corresponding filter cup valve for the suction filter, the samples contained in the enrichment of microorganisms trapped on the membrane filter, and then the membrane filter to the medium of thermostatic cultivation, count corresponding colonies.

Product features

The filter cup connectors of this filtration system are equipped with independent switches, which can filter a single sample independently or multiple samples at the same time, which can save a lot of time when testing a large number of samples.

High-quality 316L sintered stainless steel filter membrane support pad is adapted to ensure that the filter membrane does not break or perforate during the process of extraction and filtration, so as to ensure the accuracy of sample detection.

In addition, the trapped microorganisms can be evenly distributed on the filter membrane surface for the convenience of observation of experimental results.

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Pipettes are often used in laboratories, schools, research institutes, hospitals, etc. Among the many pipette types, multi-channel pipettes are pipettes with multiple tips, so some users are in use. It is found that the pipette tip suction amount is inconsistent. What causes the multi-channel pipette tip suction amount to be inconsistent? How to solve it?

Reason one: the piston is polluted

Pipettes that use long or irregular operations (such as pipetting the liquid beyond the range of the tip will cause liquid to flow into the pipette) can cause the pipette to accumulate.

Solution:

After opening, you can use a cotton swab or a soft brush to pick up a small amount of water to clean the stains. For more stubborn substances, rinse the pipette with plenty of water, then dry naturally or in an oven at 60 °C. Do not use organic solvents for cleaning or ultrasonic cleaning.

Cause two: the tip does not match the pipette

The pipette has been used for a long time, and the tip is often replaced. The replacement tip may not be a regular tip or a matching tip, which may easily lead to inconsistent pipette tips.

Solution:

Replace the tip, it is recommended to use the original pipette tip.

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The filler of polymeric HLB SPE cartridges produced by a special copolymerization technology contains a certain proportion of the hydrophilic group and the hydrophobic group. Hydrophobic divinyl benzene structures retain nonpolar compounds and hydrophilic n-vinyl pyrrolidone structures retain compounds.

The filler of polymeric HLB SPE cartridges has good water wettability and can adjust the hydrophilic-lipophilic balance by water phase, so as to obtain ideal selectivity.

The SPE cartridges have a good recovery rate of acid, neutral and basic compounds, especially suitable for the treatment of complex matrices such as blood, urine, and food.

The characteristics of polymeric HLB SPE cartridge

1. Universal packing, wide application range;
2. High water infiltration, not easy to penetrate;
3. High recovery rate and good realization;
4. Adsorption capacity and sample load were much higher than C18 bonded silica gel;
5. Tolerable to PH 1-14, compatible with most solvents.

Application of polymeric HLB SPE cartridge

i. Detect residues of the illegal drugs (antidepressants, heroin) and drug in the blood;
ii. Detect residues of antibiotics (penicillin, nitrofuran, chloramphenicol), catecholamine and microcystin toxin in food;
iii. Detect traces of veterinary drugs (tetracycline, quinolones), pesticides and mycotoxins in dairy products.

C8 HPLC columns are used to isolate many organic compounds, which are one of the reversed phase silica gel columns.

The maintenance of C8 HPLC columns requires organic solvents. Chromatographic grade methanol is recommended and different brands of chromatographic columns should be treated differently. If the chromatographic column is stored after use and will not be used for a long time, it still needs to be saturated when reused.

Warning for using C8 HPLC columns

It is necessary to ensure that the column bed does not dry up, especially in the process of sample injection detection and column washing. Otherwise, the column will dry up and a large number of bubbles will be brought in, and even cause the column bed local collapse or central cracking.

The difference between C8 HPLC columns and C18 HPLC columns

C8 is suitable for the analysis of substances with slightly stronger polarity in weakly polar substances, and C18 is suitable for the analysis of substances with weaker polarity in weakly polar substances, but the difference is not particularly obvious. Generally, substances that can be analyzed by C8 HPLC columns can also be separated by C18.

Cellulose acetate membrane filters are a kind of Millipore filtration and play an important role in membrane separation technology. Mainly used for filtration of the aqueous solution.

Features and functions

Cellulose acetate membrane filters with a uniform pore size distribution, fast filtration rate, can remove bacteria and particles and no desquamation, which plays a prominent role in sterilization and clarity improvement of injection in the pharmaceutical industry, preparation of high purity water in electronic industry, clinical test, environmental protection, and scientific research.

Advantages

Cellulose acetate membrane filters are valued because their properties such as thermal stability, chemical stability and strength are better than those of mixed cellulose ester membranes. Compared with mixed cellulose ester microporous membrane, nylon membrane and PVDF membrane, cellulose acetate membrane filters have the lowest adsorption.

Characteristics of cellulose acetate membrane filters

1. Less adhesive;
2. Hydrophilic;
3. High production;
4. Dimensional strength stability;
5. Consistent aperture structure.

Chemical compatibility of cellulose acetate membrane filters is stable in ph4-8, tolerable to most alcohols and oils. The sterilization ways are high-pressure sterilization (121 ℃ or 134 ℃), dry heat sterilization (180 ℃), gamma rays or epoxy ethane fumigation.

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Capsule filters are available in various sizes and can be autoclaved, which have four interfaces, two of which inlet and outlet of the filtered liquid are in the middle. One of the two sides is a vent, the other is a drain.

Features of capsule filters
1. 1/4 male thread interface, and various adaptors are available for conversion.
2. No filter cartridge device is required, which reduces the risk of spatter and leakage compared with the traditional filtration method, and is convenient to install.
3. It can be used as a prefilter and a terminal filter to meet extremely stringent filtering requirements.

Application
1. RFPT capsule filters are suitable for solvent and corrosive solution filtration, air and gas vent filtration.
2. RFPP capsule filters are suitable for reverse osmosis and ultrafiltration prefilter, ink filter.
3. The characteristics of RFPN capsule filters are fast flow rate and low extractable content. Glass fiber pre-filtration medium can be chosen and the service life of nylon membrane can be extended. Suitable for large volume samples filtration and samples that are difficult to filter.

Chromatographic analysis technology has been widely used nowadays. It is quite important to clean the chromatographic sample vials carefully. When the number of samples is enormous, a large number of chromatographic sample vials need to be cleaned during the experiments.

If the sample vials aren’t be cleaned, the measurements of the following experiments will not be accurate. Therefore, the experimenters should master the cleaning methods of sample vials. And in the upcoming section, we will introduce two methods.

Method One
1. Empty the test solution in the chromatographic sample vial
2. Immerse the vial into the 95% alcohol solution and wash it with ultrasonic twice. The alcohol solution is easy to flow into the 1.5mL vial and can dissolve with organic solvents in the majority of cases.
3. Pour the clean water in the vial with ultrasonic twice.
4. Empty the wash solution in the vial, and then dry it at 110 degrees Celsius for 1-2 hours. Be careful that never dry it at high temperature.
5. Cool the vial and preserve it.

Method Two
1. Wash the sample vial with clean water several times
2. Put it in a beaker filled with pure water. Wash it with ultrasonic for 15 minutes
3. Change the water and then wash it with ultrasonic for another 15 minutes
4. Put it in a beaker filled with anhydrous ethanol
5. Take it out of the beaker and naturally dry it

The FILTSTAR series syringe filter is extremely low HPLC extractable and specially designed to support the filtration of viscous samples, hard-to-filter samples which with high solids content.

Medical PP housing with imported membrane filter media helps to guarantee the filter cleanness and all filter production in the clean room and packed after QC evaluation and inspection. Fully filter size and media for more users need to match other reputable and international brand filters. When the customer needs sterilization, we can offer both EO and Gamma sterilization.

The sterilized syringe filter packed individually in the clear blistered PP housing and easier for customer use also keeps fresh shelf life.

Hawach Scientific’s filter with good feedback on Filter media choice, cleanness of filter, pore size accuracy, and no leakage, nice operation pressure, excellent filtration efficiency with extremely low or no HPLC extractable.

Filter media Choice: Nylon, PTFE, hydrophilic PTFE, hydrophilic PVDF, MCE, CA, PP, GF, PES. Glass fiber and PP prefilter available for each filter media, there are two layers of the membrane in the filter which with prefilter. Such as GF+PTFE, PP+PTFE, GF+Hydrophilic PTFE, etc.

Hawach Scientific have Qualitative filter paper and Quantitative filter paper, Wet-strengthened filter paper and Asphalt filter paper, right now we also have filter paper for Extraction.

Just as mention before, we are a professional manufacturer for filter paper, we have the regular size for stock, we also accept OEM products and Customized size.

Recently we got a new order from a US Client, they asked about the 500mm filter paper for Extraction, here is the equipment for Extraction:

If you need extraction filter paper, please do not hesitate to contact us, we have 185mm, 320mm, 400mm, 500mm to 750mm, you can choose the size which you want.

Manufactured from the same raw materials as the ashless grades, the qualitative filter paper is suited for ordinary filtration when we need to determine materials by using qualitative analytical techniques in the lab, with the features of fast flow rate due to their structure.

Qualitative filter paper has different designs. The standard qualitative filter papers with high purity are perfect for qualitative analyses where a low ash content are required. And the wet strengthened qualitative filter papers are basically used for analytical and routine analyses when no gravimetric analyses are required. We also can them for pressure or vacuum filtration.

The qualitative filter paper is available for a wide range of applications. Hawach Scientific high-quality filter paper is in Low ash content (<0.1%). Nominal retention of our products can vary from 2.5um to 20um. Filtration speed is affected by these specifications and ranges from very slow to very fast.

When choosing qualitative filter paper, you may consider about particle retention and nominal pore size required, wet strength level needed, and the diameter as well.

The bottle-top dispenser, also known as the bottle-top pipette, is an instrument for accurately measuring liquid medicine. It is widely used in the biological and chemical fields, as well as in clinical medicine, industrial and commercial laboratories.

Bottle-top dispenser material

Generally, the main materials of the bottle-top dispensers are as follows: optical glass, Al2O3, ETFE, PFA, FEP, PTFE, platinum-rhodium alloy, PP, and the like.

Range of Application

The bottle-top dispensers are mainly used for general acid and alkali, low concentration of strong acid and alkali, salt, and other liquids should be used with caution. The next thing to say is the banned solution, such as:

(1) The liquid that reacts with ETFE, FEP, PEA, PTFE, Al2O3: sodium azide
(2) The liquid that corrodes optical glass: hydrofluoric acid (HF)
(3) Liquid (H2O2) which acts as a catalytic decomposition of platinum-rhodium alloy
(4) Nicotinic acid, trifluoroacetic acid, tetrahydrofuran
(5) Explosive liquid: carbon disulfide
(6) Suspension: carbonaceous solution
(7) Limiting solution: concentrated hydrochloric acid, nitric acid, chlorinated hydrocarbons and fluorinated hydrocarbons and liquids which can form precipitates can cause the piston to stick or cause clogging (such as crystallization solution or concentrated alkaline solution).

The glass fiber extraction thimble is made of ultra-fine glass fiber and is used for various applications. It’s a high-efficiency filter device for collecting harmful substances such as soot, acid mist, and beryllium substitute. It has the advantages of high-temperature resistance, small weight loss, high efficiency, and good strength.

When you use a glass fiber extraction thimble, please note the following advice:

1. Check all parts of the sampling head before using the device to make sure they match one another and the gap is suitable.

2. When the device is loaded or unloaded, make sure it’s not subjected to the force such as tearing force or shearing to protect it from breaking.

3. If the device is found to have voids, cracks, and uneven thickness, it cannot be used as it might cause sampling failure due to airflow blow.

4. Use the device within the specified temperature range to ensure the device operates at sufficient strength. It has been reported that the strength of the glass fiber begins to decrease when it’s heated to above 200°C and then cooled.

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As an acronym for Quick, Easy, Cheap, Effective, Rugged and Safe, the method of QuEChERS achieves as a variety of sample preparation and clean-up techniques for the analysis of multiple pesticide residues in the field of agriculture.

Originally designed for the analysis of fruits and vegetables, QuEChERS extends its range to more agricultural products nowadays. After published at USDA in 2003, QuEChERS has gained significant achievement, combining few easy preparation steps and extending the range of analytes replace the old and interminable extraction methods.

The rapid growth of QuEChERS is driven by the emerging need to determine trace amounts of analytes. And the expansion of the QuEhERS shows that it is not only a method of sample extracting and cleaning-up in the lab, but also the solution of detecting lots of pesticides, herbicides, fungicides, antibiotics, and other compounds throughout the entire food industry.

QuEChERS is now a generic technique with many modifications. And all modifications have the same mission: quick and easy sample extraction and clean-up.

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Hawach Three-Branches Vacuum Filtrations system is an important branch of the vacuum filtration unit. Unlike a typical suction unit, each set can only filter one set of samples. The biggest feature is that at the same time, rely on a set of equipment and a suction pump. Three sets of samples can be filtered.

The triple-type filter product is generally connected to a filter bracket made of metal by a suction pump. Three suction filter funnels can be inserted into the bracket, and a vacuum waste liquid suction bottle is connected between the bracket and the suction pump. The whole system After the vacuum is formed, the atmospheric pressure pushes the filtrate through the filter. For users such as suspended solids detection and microbiological examination, because of the large number of samples that need to be tested every day or once, filtering multiple sets of samples at one time significantly improves work efficiency.

The SLTGF03001 laboratory Three-Branches Vacuum Filtrations system is used as an example to illustrate which components need to be included in a complete system and the functions of each component.

a. Pumping pump: The main function is to realize the negative pressure for the whole system, so as to realize the pressure difference inside and outside the system so that the atmospheric pressure pushes the filtrate through the filter membrane. Equipped with the classic SLVPGM050B Standard Diaphragm Vacuum Pumps, the needle can be used to observe the working condition of the system and adjust the vacuum and filtration speed.

b. Filter bracket: is the most important part of the system, connecting the various components of the system. A suction filter funnel can be inserted into the bracket, which is the center of the complete filtration system.

c. Filtering funnel: Place the filter and hold the liquid sample to be filtered. Equipped with the One-Branch / Three-Branches / Six-Branches filter funnel according to the number of filter holders, it can be autoclaved. The filter bowl and the funnel base are directly connected by a rotary card. They do not need to be sealed by accessories such as clamps or clamps, and can be clamped or loosened by gently rotating.

d. Vacuum pipette: holds the filtrate that has passed through the filter. The material used is conventionally made of plastic or glass. This transparent material allows the user to observe the liquid level and prevent the liquid from being sucked into the pump and damaging the instrument.

e. Water blocking protector: prevent the filtrate from sucking into the protector in the vacuum pump. It is the most easy accessory to be ignored by the user. However, its role is relatively significant, it can be 100% anti-back suction, so that the pump can not be used for years.

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The equipment and equipment in the laboratory are as comprehensive as the natural world. They say that the sparrows are small and complete, but in the laboratory, the same small but indispensable instrument has a micropipette for biochemistry. An essential tool for experimental or molecular biology experiments.

The pipette is a precision liquid-removing device that can be adjusted freely within a certain capacity range. It is commonly called a pipetting gun, but there are some common problems such as dripping, leaking, and inaccurate during use.

There are many possible reasons for “dropping”, usually due to the removal of special liquids. Some liquids with high viscosity, high density, and high saturated vapor pressure are often the “culprits” of dripping. When removing such liquids, we recommend a reverse pipetting method.

The main reason for “leakage” is that the pipette is poorly sealed and the tips are not matched. If the experiment repeatedly leaks, the leakiness of the pipette itself is eliminated, and the matching of the tips needs to be considered. Usually the same brand of pipettes and tips are matched to achieve a good system seal.

The main reason for “unacceptable” is that the pipette is not kept vertical when aspirating, or the absorbed liquid is too thick and too volatile. Your pipette may need to be calibrated when you feel that the aspiration is not accurate during the experiment. ISO 9001 and GLP require periodic pipette calibration (approximately every 3-12 months), and pipetting products should be calibrated using the gravimetric method in accordance with ISO 8655. In daily use, it is also necessary to keep the pipette vertical when aspirating. When the liquid is discharged, the tip of the gun is attached to the wall of the container and the angle is maintained at 30-45° with the wall of the container. The pipetting volume is the most accurate.

Hawach can avoid the three major issues of appeal. It combines operational and ergonomic design with advanced and innovative materials and is the perfect manual pipette for scientists who prefer to use the central pipetting button to meet the high operational requirements of the laboratory. All the features required by life science users: Robust construction, one-handed operation, complete sterilization, high precision, and easy calibration technology for long-term reliability.

Activation, also known as solvation, add a suitable solvent to expand the functional groups on the adsorbent and remove possible interferences on the adsorbent.

Equilibrium, remove the activated solvent to create a suitable solvent environment for sampling. Usually, use the same solvent of the sample solution. But for the ion exchange SPE cartridges, use the contrary solvent to the sample solution.

Retention, when the sample solution passes through the adsorbent, and the force between the adsorbent and certain compounds exceeds the force between the latter and the solvent, the compounds are fixed by the adsorbent, thus called retention; washing, after sampling, some of the interfering substances are retained together with the target compound.

It is necessary to add a suitable solution to remove the interferences to the greatest extent without affecting the retention of the target compound. Usually, the sample solvent for washing does not affect the recovery rate.

Elution, the strong elution ability solvent passes through the adsorbent to interrupt the interaction between the adsorbent and the retained compound so that these compounds flow out from the adsorbent with the solvent. Usually, the elution solvent which can only elute the target compound is the best choice.

(1) When loading and unloading or replacing the HPLC columns, the action should be light and the joint should be tightened properly. Strong mechanical vibration must be prevented to avoid voids in the bed.

(2) If the instrument is used for routine analysis, the sample type is limited, but the number of analyses is large, it is possible to configure a special column for each type of routine analysis, which helps to extend the life of the column.

(3) Avoid sudden changes in pressure and temperature and any mechanical shock. Sudden changes in temperature or dropping the column from a height will affect the filling condition in the column; a sudden increase or decrease in HPLC columns pressure will also impede the packing in the column, so it should be slowed when adjusting the flow rate when the valve is injected. The rotation of the valve cannot be too slow.

(4) The composition of the solvent should be gradually changed, especially in reversed-phase chromatography, and should not be changed directly from organic solvent to all water, and vice versa.

(5) When using the HPLC column temperature control device, it should be noted that the temperature can be raised after the mobile phase is passed.

A microporous membrane filter is a membrane separation technology, the shape of the cylindrical structure, made of 304 or 316L stainless steel, which can filter 0.1μm or more particles and bacteria in liquid and gas.

Features

microporous membrane filter has the advantages of high filtration precision, fast filtration speed, less adsorption, no leakage, acid, and basic resistance, convenient operation, and can remove the bacteria and microparticles in the injected water. Microporous membrane filters also can recoil when cleaning.

Cleaning of filter elements

For the newly purchased microporous membrane filters, the filter element of which must be sterilized using disinfectant or steam before installation. For acetate filter elements, the only disinfectant should be used for sterilization, and steam should not be used for sterilization.

Application prospect

microporous membrane filter is widely used for bacteria removal and clarification in medicine, large infusion, pure water, biological engineering as fine filtration equipment or purification device. As we all know, the filter operation has entered the membrane filtration era at present. With people’s understanding of membrane filtration, membrane filtration will be widely applied to most people’s filtration operations.

Brief introduction of the capsule filter

The bag filter is also called abandoned filter. Its shell is made of high-temperature polypropylene material. The inner filter core is made of folded filter core welded together by hot fusion. It is suitable for filtering small doses of liquid, gas or industrial precious small doses such as a 1-20L laboratory. Volume liquids, etc.

Classification of the capsule filter

According to the different characteristics of the capsule filter, different media are used. The following are the commonly used series:

1.RFPT uses hydrophobic polytetrafluoroethylene (PTFE) membrane, which is suitable for solvent and corrosive solution filtration, air and gas vent filtration.

2.RFPP capsule filter uses a hydrophilic polypropylene (PP) membrane, which is suitable for reverse osmosis and ultrafiltration, ink filtration, etc. It is suitable for filtering the water solution and solvent sample.

3. Nylon membrane is chosen for RFPN capsule filter, which has the characteristics of fast flow rate and low extractable level. The pre-filtration medium containing glass fiber can be selected to prolong the service life of nylon membrane, which is suitable for the filtration treatment of large volume samples and sad filtration samples.

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Flash column chromatography method is to separate the constituents from the mixture and thus purify it. In a word, flash column chromatography makes the samples go through the column which is filled with gel to achieve separation.

In the beginning, the founder of https://www.flashcolumns.com/product/spherical-c8-flash-columns/ Mr. Still together with his colleagues had been using medium pressure chromatography and short column chromatography to replace long column chromatography. Later they decided to combine the above two methods to overcome the defects of time-consuming and low recovery.

Initially, the gel used for filling the column is silica gel, and it is still widely applied nowadays. Laboratory workers use air pressure to push the solvent through the silica gel column, and then use the same solvent to make the sample go through the column. At last, they collect purified constituent. The whole process costs about 5 to 10 minutes.

Since the first outcome of silica gel flash column chromatography, it has been widely applied in the field of organic chemistry. Compared with high-performance liquid chromatography, the resolution ratio of flash column chromatography has reached the medium level.

The silicon hydroxyl group with strongly polar on the surface of glass sample vials will adsorb the samples. Based on such reasons, people produce hydrophobic glass surface through silylating the sample vials in order to eliminate the adsorption of the sample vials, which is widely used in protein or pesticide residue analysis.

For instance, glass has high adsorption of protein. The content of pesticide residue is very low when analyzing. Under these circumstances, if the sample vials adsorb the protein in the residue, the error will be great.

In short,the deactivated sample vials is one of the ordinary vials that the inner wall are deactivated. Or the vials are treated by silanization, which produces a hydrophobic surface. Commonly, it is not easy to see the difference from the outside. But it is very obvious when adding liquid into the vials.

There is no concave liquid surface at all. In fact, the material of general sample vials has no problem for the general application.
Compared with the materials of sample vials, there are still many problems with vial pads when using in the experiments. Therefore, we should be careful when choosing vial pads.

As a single-use, membrane-based device, syringe filter is used for the removing particulate impurities from small (less than 100 mL) liquid samples in the lab. For different applications, the syringe filter are used in for fast and efficient filtration, material purification, and sterilization.

After you select the right syringe filter and syringe for your application, you ca. draw your sample into the syringe and attach the filter onto the syringe’s end. Don’t forget to make sure that you have correctly secured the filter into the syringe tip if you use a Luer-lock filter. Then, you hold the syringe with the filter pointing up and fill it up after pushing a few drops through the filter. Next step is placing the filter tip over the collection container and push the sample with positive pressure through a syringe filter gently.

If you desire to purge the syringe filter and get maximize sample throughput, you may remove the filter from the syringe, draw air into the syringe, then reattach the filter and push the plunger, forcing some of the air through the filter.

When the polarity of the stationary phase is greater than the polarity of the mobile phase, it can be called normal phase partition chromatography or simply normal phase chromatography.

If the polarity of the stationary phase is less than the polarity of the mobile phase, it can be called reversed phase partition chromatography or simply reversed phase chromatography.

For normal phase chromatography, a low polarity mobile phase such as n-hexane can be used. For reverse phase chromatography, a strong polar mobile phase of methanol or water can be used. The stationary phase for normal phase chromatography is usually silica gel. Silica and other polar functional group amine groups, due to the strong polarity of silanol groups (SiOH) or other polar groups on the surface of the silica gel.

In the normal phase mode, ethyl acetate + n-hexane, dichloromethane + n-hexane, isopropanol + n-hexane, etc. are most commonly used as the mobile phase. A column usually made of NH2, APS and a cyano group (CN, CPS) as a bonded phase filler is called a normal phase column. Hawach’s normal phase columns are CN HPLC Columns and NH2 HPLC Columns.

The packing for reversed-phase chromatography is usually based on silica gel, and the surface is bonded to the bonded phase with relatively weak functional groups. The commonly used reverse packings are C18 (ODS), C8 (MOS), C4 (Butyl), C6H5 (Phenyl), etc. In the reverse phase, an aqueous solution of methanol, acetonitrile or the like is used. Columns made of this packing are called reversed phase columns. Hawach’s reversed phase columns are C18 HPLC Columns, C8 HPLC Columns, and Phenyl HPLC Columns.

1. Product No., for example BIO-1.

2. Pore size and flow rate, The bigger pore size, the quicker flow rate.
Fast: 60-100S/100ML @ 80-120μm
Medium: 100-160 S/100ML@30-50μm
Slow:160-200 S/100ML @ 1-3 μm

But filter paper is different from filter membrane, the pore size cannot be a certain value, these data only for your reference.

3. Ash content: Some filter papers need to be burned out during downstream analysis. Qualitative and quantitative filter papers are distinguished according to the ash value. Hawach Qualitative filter paper ash: <0.1%, Hawach quantitative filter paper <0.007%.

4. Basic weight:
Qualitative filter paper 80+/- 4 g.
Quantitative filter paper 97+/-7 g

5. Particle retention: 98% intercepted particle size, 11μm, 8μm, 2.0μm, Hawach offers more than 5 options.

6. Burst strength: a data to show the durable of the paper.
five options among 120 140,180,200 and 320 mm H2O

7. Dimensions: such as round, square, boat or folded, round diameter(mm) 70,90,10,125,150,180,240,270,300. Square size(mm): 60×60, 41×45.

More tips, just feel free to contact us!

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Generally speaking, bottle-top dispenser which is a scientific device could improve the wide application, safety performance, speed and reliability. In addition, it could save your time and work, even protect you and your samples. To be more specific, the advantages of the bottle-top dispenser are as follows:

 

1. It’s convenient to use bottle-top dispenser, which ensures the lab security. It’s time-saving and labor-saving for the reason that every bottle could have its own dispenser. In addition, the enclosed environment of solvent could eliminate the risk of accidental splashing. The smoke is under control so that there is no potential danger for human bodies.

2. The accuracy of the bottle-top dispenser is about 0.5%-0.6%. Apart from that, the narrow tube makes it more easy to dispenser in small containers whose volume is 1-5ml.

3. It could not only help daily and complicated lab working but also accelerate working space and improve total productivity. For example, if a mass of samples (50-150) need to be produced without mistake, it could easily speed up the working procedure to minimize the risk of contamination.

We recommend materials and applications of two kinds of extraction thimbles in Hawach.

The material of extraction thimbles

Due to different materials of extraction thimbles, two types of extraction thimbles are sold in the Chinese market. Cellulose extraction thimbles: high-grade alpha cellulose/seamless noble cellulose and linter of cotton without any binding elements(60% high-clean poplar fiber +40% refined cotton fiber).

Glass fiber extraction thimbles: the advanced special glass wool

Application differences and emphases

Cellulose extraction thimbles are particularly suitable for the extraction of indoor dust /toxic organics (phthalic acid) / natural substances, lacquer and binder analysis in paint colors, dust and tar determination in gases, and other similar simple Soxhlet extraction of organic components.

Glass fiber extraction thimbles are always used in specific Soxhlet extraction, such as temperature higher than 120℃, strong acid cellulose filter cartridge is not suitable for. Glass fiber extraction thimbles are also applicable to the detection of stationary pollution sources: flue gas, smoke, and dust, such as cadmium, nickel, tin, and fluorine, etc.

In addition, it is a highly efficient filter for dust, acid mist, beryllium, and other harmful substances, environmental /air exhaust detection, such as arsenic, dioxin, lead, asphalt smoke, sulfuric acid fog.

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The product mainly includes two parts: extraction boxes and purification boxes. Extraction boxes include salt bags and 50 ml centrifugal tubes. Due to the high transportation cost of 50 ml centrifugal tubes and the general unacceptability of customer laboratories, more customers will buy salt bags directly. In order to meet different customer needs, two kinds of products are designed, one is salt bag, the other is salt bag + 50 ml centrifugal tube. The purifying box of this kind of product is composed of adsorbent and centrifugal tube, including two specifications of 2 ml and 15 ml of the centrifugal tube. The adsorbent can be directly placed in the centrifugal tube. Another kind of product is a complete set, that is, extraction box + purification box. The customers of this combination product can do a whole set of experiments once they get it.

   

Therefore, in summary, the products mentioned above are divided into three categories, which are as follows:
Category 1: Extraction tube + Bagged Salt Bag: + Purification tube
Category 2: Bagged Salt Bag + Purification tube containing empty tube + salt Bag
Category 3: Only empty tube, only salt, only purification tube, only adsorbent.

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Hawach scientific is a professional vacuum pump manufacturers, product quality through a number of international standards, and exported to more than 120 countries all over the world. More detail information and quotation about the products contact with info@hawach.com.
Diaphragm vacuum pump product features :
Code : SLVPGM050A
– Speed of Evacuation:30 L/Min
– Ultimate pressure: ≧0.08Mpa
– Vacuum:200mbar
– Motor Power (W): 160W
1. No need of any working medium (no oil), no pollution. At the same time, the filter material is built into the gas exchange chamber of the machine, so as to ensure the purity of the air.
2. New technologies and materials are used in the production process. It moves easily and works smoothly, thus ensuring ideal vacuum degree and high air flow rate.
3. Temperature of 130 ℃ after automatic power can protect the motor from being damaged.
4. The diaphragm is imported rubber, corrosion resistance, long service life.
5.small size, light weight, easy to move, save laboratory space, convenient maintenance and repair.
Product application
1. vacuum suction filter
2. vacuum distillation
3. vacuum adsorption
4. solvent filtration
5. solid phase extraction
6. degassing
7. used for compression and air conversion gas

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It is well known that pipetting cycles include attaching a tip, aspirating a liquid, dispensing a liquid, and removing a tip.

Modern pipettes are mostly gas piston pipettes. The principle of the pipette is that the piston moves through the telescopic movement of the spring to achieve aspiration and discharge.

Under the push of the piston, part of the air is exhausted, the liquid is sucked in by atmospheric pressure, and then the air is pushed out by the piston to discharge the liquid. When using the pipette, it is easy to control the speed and strength of pipetting when working with the spring’s stretchability. However, pipettes of this principle require a tight bond between the tip and the pipette, so the problem is coming!

In order to make the pipette tip connection stable, the user often needs to press the tip with a hand, and in the long run, it is easy to cause repeated hand damage. Not only that, because the force is too large, more force is needed when removing the tip. In the worst case, the tip must be manually removed, thereby increasing the risk of contamination.

In addition, in addition to the above-mentioned damage to the body, such an operation is also likely to cause wear of the tip of the pipette, making the combination of the tip and the tip of the gun more difficult! Different user’s exertion will have a negligible impact on the repeatability of the experiment!

At present, the ideal solution is to combine the pipette and the tip into a specific sealing system, which ensures the repeatability of each seal, reduces the artificial force applied to the tip, and finally achieves the best-pipetting accuracy and precision.

People should face are a lot of problems when using SPE cartridges. As a consequence, we will talk about why the cartridge has a low recovery rate in the experiments.

The first reason for the low recovery rate is that the target object does not remain sufficiently on the fillers.

And why does this happen? The choice of the SPE is not the most appropriate. In response, the experimenters should choose an SPE cartridge with more retaining power. The eluting power of eluent on the sample is overly strong. As a consequence, the experimenters should decrease the eluting power. Or the load sample has high-volume or high-concentration, which leads to overloading.

The second reason is that the target object is not eluted completely. There are three aspects of the incomplete elution. The remaining capacity is too strong. The eluting power is too strong or the eluting volume is too small.

Except for the two cases mentioned above, there are still some other reasons for the low recovery rate. The experimenters should analyze the reasons according to the situation and put out some countermeasures.

HPLC is the separation of sample components between the column packing and the mobile phase for mass exchange. Therefore, the mobile phase is required to have the following characteristics:

a. the flow relative to the sample has a certain solubility, to ensure that the sample components will not precipitate in the HPLC column(or remain in the column for a long time).

b. The mobile phase is inert and does not react chemically with the sample (except in special cases).

c. The viscosity of the mobile phase should be as small as possible so that a good separation effect can be obtained when using a longer analytical column; at the same time, the HPLC column pressure drop is reduced and the life of the liquid pump is prolonged (the temperature can be lowered to reduce the viscosity of the mobile phase).

d. The physical and chemical properties of the mobile phase should be compatible with the detector used. If a UV detector is used, it is best to use a solvent with a lower UV absorption.

e. The boiling point of the mobile phase should not be too low, otherwise, bubbles will be easily generated, which may make the experiment impossible.

f. After the mobile phase is prepared, it must be degassed. Removal of traces of gases dissolved in the mobile phase facilitates both the detection and prevention of trace oxygen in the mobile phase from interacting with the sample.

Hawach Scientific Co., Ltd provides membrane disc filters with different varieties. Generally, there are two major sorts– Disc filter and Filter Roll, which respectively are distributed with many subordinate orders. Membrane disc filters, for example, have nylon, PTFE, hydrophilic PTFE, PES, MCE. etc.
Essential Technical Parameters

Pore size
0.1/0.22/0.45/0.8/1.0/3.0/5.0/10.0um
Diameter 

(Disc Filter)
13/25/47/90/142/293/300 mm
Breadth 

(Filter Roll)
254/260/270/280/310mm 

Fixed inner core: 22mm
Bubble Point
0.22, >=0.31/0.45, >=0.17(um,mpa)
Flow velocity
Proportional to the pore size
Package
47mm, 100pcs/pack;  142, 50pcs/pack
*Home-made Nylon Membrane Filters supply all the listed Pore sizes, while home-made PTFE Filters only provide size of 0.1, 0.22, 0.45, 0.8, 1.0, 3.0 um.
* The bubble point is used for testing if the pore size is qualified.
Characteristics
1 Membrane filters are applicable for both non-sterile and sterile conditions
2 The applications rely on distinguish sizes of the membranes.
Naming Rules of Product Number
Product Number consists of product name, material, pore size and Others.
For instance, MLNY13010 means that the product is named Membrane Filters, made of nylon and possesses diameter of 13mm and pore size of 0.10um.

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First, the continuous polypropylene long fibers produced by the melt-blown process are wound with polypropylene as raw material.

Second, high filtration accuracy, large flow rate, uniform structure, large contamination capacity, and long service life.

Third, good chemical compatibility, without any additives, the fiber is not easy to fall off.

Fourth, PP melt-blown filter cartridge with widely used and high dirt retention capacity.

In the deep layer of the filter cartridge, the effect of capturing particulate matter according to the density can be realized, and the effectiveness of the filter core can be given full play.

Higher soil retention means longer service life and lower replacement frequency and cost savings; The surface density of the filter element is low, but from the surface to the center of the filter element, the density increases gradually; There are no surface blind spots that will reduce the flow rate of the filter element and increase the replacement frequency.

High temperature bonded fiber; does not contain moisturizers, antistatic agents and binders; extensive chemical resistance; easy to handle after incineration; meets the requirements of FDA food and beverage industry; does not produce dissolution and release.

As a simple and fast absorption chromatography technique for the routine purification of organic compounds, flash chromatography is developed for the daily purification of reaction products in the lab, which is low costs and achieves separations of samples (0.01-10.0 g weight) in short time.
Flash chromatography is basically a compound of medium pressure and short column chromatography driven by the air pressure. The process is described as follows:
1, choose a solvent is chosen which gives the best separation.
2, select a flash column of the appropriate diameter which is machine-packed with high quality silica gel, propylamine group of silica gel and NH2. or other packs. You can check out three series of our flash column as StarFlash, PureFlash and DepuFlash.
3, fill the flash column with the solvent.
4, use pressure to push all the air from the silica gel rapidly
5, apply the sample, refill the flash column with solvent, and elute the sample.
Generally, it takes so fast (5-10 min)The time of eluting the components from the flash column. Small fractions are typically collected early in the elution while the larger ones are collected at the end of the chromatography.

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What is the sample vial?
Sample vials, also named as sampling bottles, purification bottles, aseptic bottles, clean bottles, filter bottles, etc., are essential for detecting pollution. According to International Standard, it is specially qualified for cleaning appliances so that the vial totally differs from other liquid samples.

Categories of the sample vial

According to the volume, the sample vial can be divided into 150ml and 250ml, which are respectively involves outer diameter 50mm * caliber 22mm * bottle height 130mm and outer diameter 70mm * caliber 30mm * bottle height 140mm.
In addition, the sample vial specialized for particle counter notably has three main applications. The first is collecting liquid samples for particle contamination test, and the second is holding highly purified reagents with the last—filling granular standard materials and standard samples.

Manufacturing Process

Take the sample vial which is designed for particle counter for example.
Its manufacturing requires technological process such as a high-precision ultrasonic cleaner, thousand-level clean air, stoving, sealing, etc.. It is also a container for testing particle counter of liquid contamination, suitable for sample collection, high cleanliness reagents, granular reference materials and samples for various liquid granularity tests.

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Nowadays customers are now more concerned with the quality of the filter, especially the extractable level of the filter media. A low backgrounding and super clean filter media with no or extremely low HPLC extractables can keep the experiment without unwanted column peak.

In Hawach Scientific, we used super clean membrane filter with medical grade PP filter housing as filter material, all production were accomplished in 100,000 grade clean room to make sure its super clean environment.

Three Series available as below:
WINSTAR: OEM Filters, Color code; Economic Series; fit every market
FILTSTAR: OEM Filters, Clear color without Color code; Standard Series; Full range of filter size and filter media
PURSTAR: OEM Ffilters, Clear Color without Color code; Only for bulk production

All of Hawach filter series with extremely low HPLC extractables and the filters without complaint within five years.

For any more questions or finding more detailed information for the better filters, please contact us at info@hawach.com

SPE Technique Introduction

SPE(Solid-phase Extraction), is an increasingly popularized technology of sample pretreatment, which is established on the basis of traditional LLE(Liquid-liquid Extraction). Combined with the substance interaction mechanism that like dissolves like, and basic knowledge of stationary phases with currently widely applied HPLC(High-Performance Liquid Chromatography) and GC(Gas Chromatography), the skill has been gradually developed.
Besides, SPE features a small number of organic solvents, convenience, safety, and high efficiency.

SPE Technique Category

According to the similar dissolution mechanism, SPE can be divided into four types– reverse SPE, positive SPE, ion exchange SPE, and adsorption SPE.

SPE Technique General Applications

SPEs are mostly utilized to treat liquid samples extracting, concentrating and purifying the semi-volatile and non-volatile compounds. If solid samples are provided, they have to be processed into liquids ahead. Nowadays, domestic applications mainly focus on the analysis of polycyclic aromatic hydrocarbons(PAHs) and polychlorinated biphenyls(PCBs) for watery conditions, pesticide and herbicide residues in fruits, vegetables and food, antibiotic analysis and clinical drug analysis.

SPE Technique Typical Applications

● Biological fluid analysis
● Analysis and monitoring of drinking water, groundwater, and sewage
● Volatile oils, plant tissues, fruits, vegetables, and grains
● Liquid drug samples, soils, and sediments
● Meat, fish and other animal tissues
● Tablets and other solid drugs

Hawach Scientific is a modern enterprise contains well integration of R&D, production, sales, and after-sales services.

We have a sales team for filter paper, after more than 16 years promotion, the high praise from the market for our quality and services, filter papers have various size and functions, here are our summary for filter papers:

1. Lab filter paper: Qualitative filter paper and Quantitative filter paper, we have the full size of filter paper for you choose, accept OEM and customized size. Right now, Hawach Qualitative filter paper we can customize max diameter is 750mm, Quantitative filter paper max diameter is 300mm;
2. Asphalt filter paper: Special filter paper for Asphalt filtration, 400mm diameter, 350g/m2, 50pcs/pk, we also can accept OEM and customized size;
3. Sugar filter paper: Special filter paper for Sugar, our regular size is 185mm, we also can accept OEM and customized size;
4. Wine filter paper: Special filter paper for Wine, 80g/m2, Medium speed, 7-10um, have very good performance for wine, we also can accept OEM and customized size;
5. Hawach Filter paper has a round disc, sheet square, Roll type.

Hope the above contents are clear enough for you to understand our filter papers, any questions or help you need, please don’t hesitate to contact us.

Thank you and have a nice day.

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Hawach electronic bottle-top dispenser can dispense liquid directly from a reagent bottle or from any container via a versatile base.

The electronic bottle-top dispenser is the new generation of the intelligent electronic bottle-top dispenser, which can complete the liquid separation work you need with a simple press on the LCD screen.

Do you want to perform a series of 1 – 9999 large scale repeat separations on different reagents? Want to divide the volume of liquid into several volumes at once? Hawach electronic bottle-top dispensers can help you.

Features of electronic bottle-top dispensers

Built-in high-precision electronic motor, no lubrication, no maintenance consumables, reduce maintenance costs, can be integrated with the automated production line at the same time through the software or signal line. Improve work efficiency and reduce cost. Easy to clean, can be used for aseptic filling.

In addition, the electronic bottle-top dispenser has a step function in addition to conventional liquid dispensers. The standard step function can realize several times of liquid dispensers of the same or different volumes after a piston cleaning fluid, which is required for unconventional and flexible liquid discharge.

1.Classification of extraction thimbles

The extraction thimble, as its name implies, is a cylindrical element used for extracting. According to the material, it can be divided into three categories: cellulose exaction thimbles, glass fiber exaction thimbles, and quartz fiber exaction thimbles. As quartz fiber exaction thimbles cannot be produced in China at present, our company is mainly the first two products. In addition, the material and function of the filter cartridge and filter paper are similar.

2.Application of the difference between extraction thimbles

Cellulose exaction thimbles

The filter cartridge is suitable for general cable extraction. It is mainly used for indoor dust control and extraction of indoor toxic substances (terephthalic acid).

Glass fiber exaction thimbles

Glass fiber filter cartridge is suitable for Soxhlet extraction when cellulose filter cartridge temperature is higher than 120 C and strong acid is not available for trial use.

In addition, there are fixed pollution sources of flue gas, smoke and dust detection, such as cadmium, nickel, tin, fluoride and so on, as well as fixed pollution sources of waste gas benzo ratio, lead, asphalt smoke, sulfuric acid fog, environmental air and waste gas arsenic, dioxins and so on.

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QuEChERS is a pretreatment that has the characteristics of Quick、Easy、Cheap、Effective、Rugged and Safe, which is the reason why it is becoming more and more popular in the new testing methods. It was developed by Professor Anastassiades in 2003, which was used in agricultural testing at first.

The principle of QuEChERS is similar with the HPLC and SPE. QuEChERS purifies the substance because the interaction between the adsorptive stuff and the impurities of substrates can help absorb the impurities. Detailedly, after the homogenized samples are extracted by acetonitrile and the salting-out method, the disrupters of the samples combined with the PSA or some other adsorptions, such as organic acid and aliphatic acid. And then the impurities are removed by centrifugation. Therefore, the quality determines the test results.

QuEChERS is widely used in many fields as a testing method, especially in Pesticide Residues Determinations. We can use it to purify substances in numerous field as long as the percent recovery of the samples is in the allowable ranges and the substrates fit the needs of testing.

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The laboratory vacuum filter unit is designed for laboratory users to filter solid-liquid separation of liquid samples.

Stainless Steel Vacuum Filtrations operation steps:

1. Place the glass filter bottle on the stainless steel vacuum filtrations and insert the silicone plug of the funnel base into the filter bottle.
2. Use a line to connect the filter pump port and the filter bottle.
3. Lay the filter in the funnel base and gently rotate it with the filter bowl.
4. Connect the yellow bottom drain tube to the bottom drain port of the suction filter bottle. The drain tube is clamped with the clamp.
5. Press the power switch again to start the filter pump.
6. Pressure regulators can be used to adjust vacuum (suction) and filtration rate.

The body material of the all-stainless steel surface can be cleaned by simply wiping with a cloth during routine maintenance.

In addition, customers should pay attention to the following matters, good use habits can avoid human damage and extend the life of the machine. Considerations include:

1. Check that the voltage marked on the nameplate on the back of the instrument matches the local voltage.
2. Use the instrument in a clean, dust-free, ventilated space with a temperature below 40 °C.
3. The front of the vacuum filter unit has a buffer cup to prevent a large amount of aqueous solution from being drawn into the filter pump, but it is not completely prevented. Please take care to prevent the liquid from sucking back. If you have already taken in the liquid, stop using it immediately and send it for repair as soon as possible.
5. The stainless steel vacuum filtrations must be placed on a level desktop.
6. Turn off the power before installing or removing the silicone tube.
7. Do not move, collide or tilt the machine while the instrument is in operation.
8. The filter element is used to prevent dust from entering the filter pump and to purify the gas at the gas outlet, so that impurities will not be sucked into the pump. Please check regularly, if the color changes significantly, please contact the dealer for replacement.

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Single-Channel Manual Pipette Features

Tip the pop-up button for one-handed operation.
The handle hook can be easily attached to the palm of your hand.
Clear readings.
The tip retracting rod and nozzle can be removed for easy cleaning and maintenance.
Rotatable dispensing head makes the pipetting process more convenient.
Disposable tips are all popped up, the one-handed operation can be completed.
Durable conical material provides excellent chemical resistance.
Models larger than 10μl have replaceable safety cone filters to help prevent internal contamination and damage.
Tip cone can be disassembled for easy maintenance.
Tip cone design allows the tip to be easily removed from the slot.
And rely on visual verification whether it is completely absorbed firmly.

1.Friction sealing system

A pipette with a friction sealing system relies on a user’s forced pressing to secure the tip to the pipette, and the magnitude of the force varies from person to person.
Increased force required for tip assembly and withdrawal.
The tip is easy to lose, causing it to fall off or leak.
Reduced repeatability of experimental results.
Pipette link wear.

2.ClipTip system

There is a connection point between the pipette and the tip of the ClipTip interlocking point seal technology, which is sealed by locking the tip to the connection point.
Tip assembly and exit with minimal effort.
Each channel is completely sealed.
Avoid loosening of the tip.
Reliable reproducibility.

3. Card type tip for worry-free pipetting

The manual pipette ensures that each channel is completely sealed when the tip is locked in place. Whether you use a single or multi-channel pipette, you get the capacity you need to accelerate your R&D.

Polymeric MCX SPE cartridges are used to extract strongly alkaline compounds. MCX is a mixed strong cation exchange adsorbent obtained by bonding sulfonic acid groups on highly crosslinked PS/DVB surface. It has both reverse phase and cationic exchange retentive properties and good retention ability for alkaline compounds.

Characteristics of polymeric MCX SPE cartridges

1. High retention of basic compounds;
2. Large specific surface area and high ion exchange capacity;
3. Wide pH tolerance range (pH 1-14), stable in organic solution;
4. No blank background interference;
5. Stable quality and good reproducibility;
6. It is easy to operate and can achieve an excellent flow rate.

Parameter of polymeric MCX SPE cartridges

1. Specific surface area: 600 m2/g;
2. Average particle size: 40μm;
3. Average aperture: 300 Å.

Application of polymeric MCX SPE cartridges

1. Detect pesticide and veterinary drug residues in food, such as clenbuterol and malachite green;
2. Analyze drugs and their metabolites in the biological matrix, such as anti-estrogen drugs and benzodiazepines.
3. Polymeric MCX SPE cartridges are especially suitable for milk analysis of melamine in food and feed.

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The reversed-phase HPLC columns may be repeatedly injected into a sample containing a strongly retained material, and in particular, the sorbent components such as large molecular weight or hydrophobic biological flow proteins and strong alkaline substances may be adsorbed on the silica medium.

In addition, some mobile phase additives such as ion-pairing test reagents and reactants can adsorb on the filling surface and change their properties. Contaminated columns can cause peak shape differences, poor retention of repeatability, high back pressure, and baseline drift. Typically, these columns can be cleaned using organic solvents or agents capable of destroying contaminants and binder phases or silica surfaces.

The users should be careful when using reagents that are corrosive or destructive to the binding phase. Additionally, the use of sample preparation minimizes contact between the HPLC columns and undesired materials to reduce contamination. We suggest using the HPLC protect column as pre-filter. Use Pre-filter, HPLC protect column, can reduce pollution from contamination and possibly store the analytical HPLC columns.

First, the purpose of the request

The colorectal flora in water was determined by the membrane method.

Second, the basic principles

The filter membrane method uses a filter to filter the water sample, and the bacteria are trapped on the filter membrane, and then the filter membrane is placed on an appropriate medium for cultivation, and the coliform group can be directly grown on the membrane, so that it can be directly counted. The filter membrane used is a porous nitrocellulose membrane or a cellulose acetate membrane, which is water-based filtration membrane and has a pore diameter of about 0.45 μm.

Third, test raw materials and equipment

Experimental materials: Yihongmei blue agar plate or Endo’s agar plate, lactose peptone fermentation tube with inverted small casing), sterilized water, river water or lake water;

Equipment: tweezers; clamps; beakers; vacuum pumps; filter membrane; filters, etc.

Fourth, the operation steps

1. Filter membrane sterilization

The filter membrane was placed in a beaker containing distilled water, boiled for 15 minutes by heating, and boiled three times in total. After boiling twice, the water was washed 2-3 times and then boiled to wash away the residual solvent on the filter membrane.

2. Filter device

The sterile filter base, filter membrane, funnel and filter bottle are installed in a sterile procedure, and the filter membrane was transferred to the base of the filter with sterile tweezers (immersed in 95% alcohol and sterilized by flame). Others can be operated directly by hand or with a clamp, but do not touch the rubber stopper part that protrudes into the filter bottle to avoid contamination.

3. Connect the filter bottle to the vacuum pump.

4. Add water sample filtration

For a filter with a diameter of 50 mm, the amount of water to be filtered generally requires a larger number of filter devices, and more than 50 filters are suitable. Therefore, it is preferable to use a multi-filter, which can reduce errors. Generally, 300-500 ml of deep well water or treated river water and lake water can be sampled; 1-100ml can be sampled for relatively clean river water or lake water; severely contaminated water samples can be diluted first; unknown water samples can be sampled. Make three dilutions and choose the appropriate dilution for the number of colonies to calculate. In this experiment, 100 ml of relatively clean river water or lake water was added to the filter funnel and capped.

5. Start the vacuum pump for oil filtration.

6. After pumping, add the same amount of sterile water and continue to filter, in order to flush the funnel wall.

7. After the filtration, close the vacuum pump, use the sterile tweezers to take the edge of the filter, and place the side without bacteria on the Endo agar plate or the Espresso blue agar plate. There must be no air bubbles between the filter and the medium.

8. The plate was inverted and incubated at 37 °C for 22-24 hours.

9. Colonies that meet the characteristics of coliform colonies are picked and subjected to Gram staining and microscopic examination.

10. Microscopically, Gram-negative, Bacillus-free colonies were inoculated with a lactose-protein fermentation tube, and cultured at 37 °C for 24 hours. The acid-producing and gas-producing group was positive for coliform bacteria.

Melt-blown filter cartridges are shaped filter cartridges, which made of non-toxic and odorless polypropylene particles after heating, melting, spinning, traction.

Melt-blown filter cartridges are not only used in water purification, but also have excellent chemical compatibility, suitable for filtration of the strong acid, strong alkali, and organic solvent.

Features of melt-blown filter cartridges

1. Strong ability to absorb pollution;
2. Long service life;
3. Low cost, widely used;
4. High filtration precision;
5. Large flow and even structure;
6. Good chemical compatibility, no additives, fiber is not easy to fall off.

Application of melt-blown filter cartridges

1. Pharmaceutical industry: pre-filtration of all kinds of injection, medicine liquid and injection bottle washing water, large infusion, various antibiotics, and traditional Chinese medicine injections.
2. Food industry: filtration of alcohol, beverage and drinking water.
3. Petroleum and chemical industry: all kinds of organic solvents, acid, lye filtration, oilfield water filtration.
4. Water industry: all kinds of pure water system pre-filtration and drinking water filtration.

Particulate matter can be effectively captured in the deep layer of melt-blown filter cartridges, and the effectiveness can take effect 

Rapid chromatography
Technology for the separation and purification of natural products and biological macromolecules. It has the advantages of easy operation, cheap price, and rapid analysis, and a few other technologies can match the rapid chromatography in the application of purifying organic matter. Rapid chromatography is a typical low-pressure technique. The chromatographic column is filled with silica gel adsorbent with the particle size of 40-60um, and the mobile phase with low viscosity needs to choose a smaller particle size.

Flash column
With the progress of Times, more and more laboratories have a higher degree of automation for separation and purification—rapid chromatograph (low and medium pressure preparative chromatography), in the pharmaceutical outsourcing companies often referred to as the

Rapid chromatography
Technology for the separation and purification of natural products and biological macromolecules. It has the advantages of easy operation, cheap price, and rapid analysis, and a few other technologies can match the rapid chromatography in the application of purifying organic matter. Rapid chromatography is a typical low-pressure technique. The chromatographic column is filled with silica gel adsorbent with the particle size of 40-60um, and the mobile phase with low viscosity needs to choose a smaller particle size.

Flash column
With the progress of Times, more and more laboratories have a higher degree of automation for separation and purification—rapid chromatograph (low and medium pressure preparative chromatography), in the pharmaceutical outsourcing companies often referred to as the flash column machine. As the name suggests, this is a replacement for the hand-crafted silicone column, which we call the flash column. With the gradual popularity of the domestic machine, the use of higher grade.

machine. As the name suggests, this is a replacement for the hand-crafted silicone column, which we call the flash column. With the gradual popularity of the domestic machine, the use of higher grade.

The cleaning of sample vial is very important. Usually, according to the principle of glass instrument washing and the degree of pollution to choose cleaning methods, there is no fixed mode. The specific methods are as follows:

Method one:
1. Dry the sample in the sample vial.
2. Immerse in 95% alcohol, wash twice with ultrasound and then dry, because alcohol is easy to enter 1.5mL vial, and can be soluble with most organic solvents to achieve;
3. Pour in clear water and wash twice with ultrasound.
4. Pour the lotion in the drying vial and bake at 110 degrees Celsius for 1-2 hours. It can’t bake at high temperature.
5. Cooling and preserving.

Method two:
1. Rinse the tap water several times.
2. Put it in a beaker filled with pure water and ultrasonic for 15 minutes.
3. Change the water and ultrasound for 15 minutes.
4. Finally, take out the natural air-drying.

Method three:
1. Soak in methanol for 20 minutes, then dry the methanol.
2. Fill the sample bottle with water, wash it with ultrasound for 20 minutes, and then dry it.
3. Finally, the sample vial will be dried.

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Consisting of a filter medium and housing or holder that constrains and supports the syringe filter media in the sample’s path, filters are good tools when you need removing particulates from samples in the lab.

We have three basic types of laboratory filters.

Membrane filters size rating of the membrane is determined the size of the pores. Centrifugal filters are suitable for separating such as protein or nucleic acid desalting and concentration. These devices drive the liquid through the filter through centrifugal force. And syringe filters which consist of a filter element and housing assembly are used when a sample must be filtered before entering a syringe.

To select the best filter for your process, ask yourself the following questions:

1. What are you going to filter?
2. What is the size and nature of the particles or molecules to be removed?
3. Chemical composition of your sample.
4. Viscosity.
5. Suitable temperature.

More to be concerned upon your applications:

1. To achieve the separation, what pore size or nominal molecular weight rating is required?
2. Do you need a sterilizing filtration?
3. How quickly do you need to filter?
4. Pressure-driven or vacuum-driven filtration?

Now, your knowledge is improved to obtain accurate separation of your sample, mobile phase or other liquid.

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Columns Ahead Statement

Generally speaking, SPE/FLASH is mainly applied to the pretreatment of samples.

People can easily perceive that SPE/FLASH columns separate salt and sugar, while HPLC ones can make glucose, maltose and sucrose apart from the sugar solution, which posses more similar properties to each other than salt and sugar do. Hence, the HPLC column requires higher power of stationary phases and separating with a corresponding higher prices.

Specific Comparison

The biggest feature of filter paper is paper with good filtration performance. At present, the filter papers produced in China mainly include quantitative analysis filter paper, qualitative analysis filter paper and chromatographic qualitative analysis filter paper.

Quantitative filter papers are cellulose filter papers, as are qualitative filter papers. They are not suitable for other types of filter paper, such as glass microfiber filter paper.

1. The general qualitative filter for filtering solution, chloride, sulfate and so do not need the qualitative test of numerical calculation; and quantitative filter paper is used for numerical calculation of the precision filter.

Qualitative analysis filter paper generally has more residual ash, which is only used for general qualitative analysis and for filtering precipitation or suspension in solution but can not be used for quality analysis.

The types and specifications of qualitative analysis filter paper are basically the same as those of quantitative analysis filter paper, indicating fast, medium and slow speed, but printing fast, medium and slow words.

2.Quantitative analysis filter paper in the manufacturing process, the pulp is treated with hydrochloric acid and hydrofluoric acid and washed with distilled water. Most of the impurities in the paper fibers are removed, so the residual ash after burning is very small, which has little effect on the analysis results. It is suitable for precise quantitative analysis.

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A bottle-top dispenser is a device installed at the mouth of a solvent bottle to take a large amount of solution and has been constantly updated and improved to meet the growing operational requirements of the laboratory for more than ten years.
There are two kinds of bottle-top dispensers: mechanical (0.5 – 5ml, 1 – 10ml, 2.5 – 25ml and 5 – 50ml) and electronic (0.1 – 99.9ml).
Installation instructions of bottle-top dispensers
1. Install the suction pipe;
2. Install the return pipe;
3. Install the distribution pipe;
4. Install the reagent bottle;
5. Prepare the suction and separation;
6. Get rid of air bubbles;
7. Quantitative liquid separation;
8. Handle after use;
9. Simple maintenance and cleaning.
All-purpose/hydrofluoric acid bottle-top dispensers
They are suitable for hydrofluoric acid, strong acid, nicotinic acid, alkali, solvent, and extreme dangerous liquid. The valve has no spring structure, no corrosion and metal ion contamination reagent, suitable for trace analysis. Strengthen the safety valve to prevent the release of niacin/odor chemical liquid odor.
The materials of bottle-top dispensers are mainly optical glass, Al2O3, ETFE, PFA, FEP, PTFE, platinum-iridium alloy, PP (safety helmet).

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Cellulose extraction thimbles are widely used in Soxhlet extractors. Soxhlet extraction is a widely used technology to analyze lipids or pesticides in food and soil materials and others.
Soxhlet extraction is the continuous extraction of the required components in the solid mixture by using the principle of solvent reflux and siphon. When the liquid level of the solvent in the cellulose extraction thimbles under the backflow exceeds the siphon of the Soxhlet extractor, the solvent in the extractor barrel flows back into the round-bottom flask, which is a siphon.
Features of cellulose extraction thimbles
They are made of high quality cellulose wool with high mechanical strength and retention.
Standard casing wall thickness is approximately 1mm (particle retention 10μm).
The thickened casing wall thickness is approximately 2mm for high retention and wet strength, dry strength or special requirements (particle retention 6μm).
High-purity materials of cellulose extractive thimbles ensure the reliability and reproducibility of the analysis results.
For conventional automated extraction instruments, Hawach provides you with cellulose extractive thimbles that match the size of the instrument for automated use.

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According to the research from the United States Department of Agriculture, the QuEChERS method which extracts pesticide from foods is fast, convenient, cheap, effective and secure.

When it compares to the traditional SPE method, QuEChERS not only uses less solvent but also adopts the novel dSPE which could disperse the SPE purification much quicker. Its method which includes AOAC official method and amendment has been posted on the Internet, whose basic steps are as follows:

Step 1: Sample preparation and extraction. Consistently homogenizing the articles, and adding acetonitrile solvent for shaking extraction. More than that, salts, acids and buffers could be added in order to improve the extraction efficiency and protect sensitive analytes. In addition, the extraction efficiency could be monitored by adding alternative standards.

Step 2: Extraction Elimination. Clearing up the subsamples of solvent extraction by dSPE, which improves QuEChERS technology. Small polypropylene centrifugal tubes prefilled with MgSO 4 and SPE adsorbent are adopted in order to eliminate the extra water and unnecessary pollute from the extracted samples. After stirring and centrifugation, the purified extraction could be analyzed by multiple techniques.

Step 3: Sample analysis. Sample’s PH could be adjusted in order to protect the sensitive pesticide or exchange the solvent to improve analysis of GC/MS or LC/MS. The internal standards could be supplemented.

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Hawach standard diaphragm vacuum pump, with advanced design, high working efficiency and long service life, is a new generation of high-tech integrated products. It is also used in medical and pharmaceutical products in addition to suitable applications for circulating water vacuum pumps and rotary vane vacuum pumps. Analysis, fine chemicals, biochemical pharmacy, food inspection, criminal investigation technology, etc., are the supporting products of precision chromatography instruments, and also the necessary equipment for the laboratory. Has obtained a number of national patents, safe and reliable, and easy to apply.

Product description:
* No working medium (no oil) is required to produce pollution, and the gas exchange chamber of the machine has built-in filter material to ensure the purity of the air.
* Adopt new technologies and new materials in the production process. It is easy to move and smooth, ensuring ideal vacuum and high air flow.
*Special motor has passed the CE certification of the European Union. It is provided by ODM, a professional export motor manufacturer. It has a reasonable rotation design and is equipped with a temperature protector. It automatically cuts off when the pump temperature reaches 130°C, and protects the motor from long-term operation. damage.
*Using non-friction film body movement, no heat generation, no friction loss diaphragm adopts imported rubber, corrosion resistance and long service life.
* The body is designed with an automatic cooling exhaust system to ensure continuous operation for 24 hours.
*Adjustable pressure design to meet a range of vacuum and gas flow rates.
*The bearing adopts imported bearings, which is stable in operation, low in noise and high in work efficiency.
*The parts of the anti-corrosion pump that are in contact with the gas are treated with Teflon surface and have complete chemical resistance. Small size, light weight, easy to move, save lab space, easy to repair and maintain.

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1. Aspiration and drainage
Vertical aspiration; the tip of the tip is immersed in the liquid surface below 3mm. The tip of the tip is pre-flushed in the liquid before the aspiration; slow suction and slow release; if the amount is small when the liquid is discharged, the tip of the tip should be the inner wall of the container.

2. Pipette placement
Pipettes that hold liquid should not lay flat, and the liquid inside the tip can easily contaminate the inside of the gun and may cause the spring of the gun to rust. If the pipette is not in use, it is recommended to hang it vertically on the pipette holder. The product should be adjusted to maximum after each experiment, allowing the spring to return to the prototype to extend the life of the pipette.

3. When sucking the liquid, be sure to release the thumb slowly and smoothly. Never let it suddenly loosen, in case the solution is sucked too fast and flush into the pipette of the pipette to corrode the plunger and cause air leakage.

4. In order to obtain higher precision, the sample solution needs to be sucked once before the sample is taken, and then the liquid is officially pipetted. When the serum protein solution or the organic solvent is taken up, a “liquid film” remains on the inner wall of the tip, causing the liquid discharge amount. It is too small and produces errors.

SPE column or SPE cartridges are based on liquid-solid phase chromatography theory, it is a kind of extraction, separation, concentrated sample preparation unit. Mainly used in sample pretreatment of various foods, agricultural and livestock products, environmental samples and target compounds in biological samples.

Solid phase extraction fillers are usually chromatographic adsorbents. Hawach offers the following four categories.

The first one is based on silica gel (e.g. C18, C8, etc.); the second one is based on high polymers, such as polystyrene – Divinylbenzene and the like; the third type is mainly inorganic materials, such as Flory diatomaceous earth, alumina, graphitized carbon, etc.; the fourth type is a special column, such as an azo dye detection column.

Hawach SPE cartridges are made from medical PP and formed as injection syringe type, equipped with two pieces medical PE sieve plate, and chromatographic adsorbents (fillers) are filled between these two. The upper end of the SPE cartridge is open, and the lower end is a liquid outlet, and the liquid is discharged from the outlet after passing through the adsorbent. The conventional size of the column tube is 1 mL, 3 mL, 6 mL, and 12 mL.

In addition, Hawach can be customized according to your specific application requirements.

With the development of society and technology, chromatographic analysis theory has also been developing rapidly. HPLC column has now been widely applied in every field of laboratory analysis. HPLC column gathers function of both detection and separation. With the right choice, use, and maintenance, you can keep good performance of the HPLC column. Otherwise, you will make it scrap fastly.

HPLC is a branch of chromatographic, using high-pressure infusion system to make the single or mixed solution and buffer mobile phase pump into the column with the stationary phase. After each component is separated, the solution can flow into the detector in order to be analyzed. Normally, the great diversity and complex matrix of the sample are key reasons to make HPLC column be easily polluted.

The Choice of HPLC Column

In general, the first thing you have to consider when choosing an HPLC column is the sample’s cleanliness. For most researchers, the most appropriate length of guard column is 2 cm or 3 cm. The length of a guard column, the more chromatographic packings can be filled. Meanwhile, longer guard column can reduce more pollutants and extend the retention time of samples.

The Right Use of HPLC Column

1. Add Guard Column
2. Filter Mobile Phase and Sample
3. Purify Sample
4. Avoid Overhigh Column Pressure
5. Pay Attention to Temperature and PH Level
6. Correct and Timely Wash

The maintenance of the HPLC Column
1. Softly and Moderately Change and Handle the Column
2. Add One Column for Each Analytical Instrument to Extend Service Life
3. Avoid Sudden Change of Temperature and Pressure Causing the Mechanical Shock
4. Generally, Do Not Recoil HPLC Column
5. Do Not Directly Infuse Samples with Complex Matrix into HPLC Column
6. Fill HPLC Column with Acetonitrile or Methanol to Preserve It
7. Wash the Chromatographic Analysis System Timely after Use

First, the purpose of the request

The colorectal flora in water was determined by the membrane method.

Second, the basic principles

The filter membrane method uses a filter to filter the water sample, and the bacteria are trapped on the filter membrane, and then the filter membrane is placed on an appropriate medium for cultivation, and the coliform group can be directly grown on the membrane, so that it can be directly counted. The filter membrane used is a porous nitrocellulose membrane or a cellulose acetate membrane, which is water-based filtration membrane and has a pore diameter of about 0.45 μm.

Third, test raw materials and equipment

Experimental materials: Yihongmei blue agar plate or Endo’s agar plate, lactose peptone fermentation tube with inverted small casing), sterilized water, river water or lake water;

Equipment: tweezers; clamps; beakers; vacuum pumps; filter membrane; filters, etc.

Fourth, the operation steps

1. Filter membrane sterilization

The filter membrane was placed in a beaker containing distilled water, boiled for 15 minutes by heating, and boiled three times in total. After boiling twice, the water was washed 2-3 times and then boiled to wash away the residual solvent on the filter membrane.

2. Filter device

The sterile filter base, filter membrane, funnel and filter bottle are installed in a sterile procedure, and the filter membrane was transferred to the base of the filter with sterile tweezers (immersed in 95% alcohol and sterilized by flame). Others can be operated directly by hand or with a clamp, but do not touch the rubber stopper part that protrudes into the filter bottle to avoid contamination.

3. Connect the filter bottle to the vacuum pump.

4. Add water sample filtration

For a filter with a diameter of 50 mm, the amount of water to be filtered generally requires a larger number of filter devices, and more than 50 filters are suitable. Therefore, it is preferable to use a multi-filter, which can reduce errors. Generally, 300-500 ml of deep well water or treated river water and lake water can be sampled; 1-100ml can be sampled for relatively clean river water or lake water; severely contaminated water samples can be diluted first; unknown water samples can be sampled. Make three dilutions and choose the appropriate dilution for the number of colonies to calculate. In this experiment, 100 ml of relatively clean river water or lake water was added to the filter funnel and capped.

5. Start the vacuum pump for oil filtration.

6. After pumping, add the same amount of sterile water and continue to filter, in order to flush the funnel wall.

7. After the filtration, close the vacuum pump, use the sterile tweezers to take the edge of the filter, and place the side without bacteria on the Endo agar plate or the Espresso blue agar plate. There must be no air bubbles between the filter and the medium.

8. The plate was inverted and incubated at 37 °C for 22-24 hours.

9. Colonies that meet the characteristics of coliform colonies are picked and subjected to Gram staining and microscopic examination.

10. Microscopically, Gram-negative, Bacillus-free colonies were inoculated with a lactose-protein fermentation tube, and cultured at 37 °C for 24 hours. The acid-producing and gas-producing group was positive for coliform bacteria.

Filter cartridges are purification equipment, with long service life, strong pollution capacity and low pressure and other characteristics, which are suitable for pharmaceutical, food, petroleum, electronic, chemical, metallurgical and textile industries.

Features of filter cartridges
1. Excellent chemical compatibility, suitable for filtering strong acid, strong alkali, and organic solvents;
2. Large filtration area;
3. The low-pressure difference, strong pollution carrying capacity, long service life;
4. Wide filtering accuracy;
5. Protect the engine while meeting the intake amount of air;
6. Effectively reduce the noise caused by air intake from the engine;
7. Fuel economy

Applicable scope of filter cartridges

Vacuum coating, machinery, optical disc, metallurgy, petroleum, chemical industry, papermaking, food, medicine, electronics, electric power, ceramics, water diversion, printing and dyeing, sugar making, refrigeration equipment, and other fields.

Kinds of filter cartridges
1. Membrane pleated filter cartridges;
2. Metal filter cartridges;
3. Microfiber pleated filter cartridges;
4. Others.

The service life of filter cartridges

According to the raw materials used, the service life of the filter element will be different. With the extension of service time, impurities in the water will block the filter element.

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The formation of a flash phenomenon
The boiling point of water is higher than 100℃ when the water is heated under a certain pressure. The higher the pressure, the higher the boiling point of water and the higher the heat content. When the pressure decreases, some sensible heat is released, and this excess heat will be absorbed in the form of latent heat, causing some water to be “flash” into steam.

The differences between SPE column, Flash column, HPLC column
In general, both the SPE column and Flash column are used in the pre-processing of the sample being analyzed. After the pre-processing is completed, the sample is then sampled. The HPLC column was used to separate glucose, maltose, and sucrose from sugars in an HPLC (High-Performance Liquid Chromatograph) instrument.

It should be noted here that the properties of the salt and the sugar are very different, so they are well separated. However, the properties of glucose, maltose, and sucrose in sugars are very similar, and it is difficult to separate them. Therefore, the separation capacity of the HPLC column is much larger than that of the SPE column and Flash column.

Hawach ensures the accuracy of each sample vial and cap specification, from the initial design to the final photoelectric scanning inspection process, our strict tolerance control throughout the entire manufacturing process.

Integrity, cleanliness, and uniformity of a sample vial are critical to today’s demanding applications. To prevent contamination and avoid instrument damage, proper selection of spacer is crucial.

The pad of a sample vial may degrade resulting in sample contamination. Rubber pads only stay stable under 90 ℃, and therefore not suitable for high-temperature applications. In general, PTFE-lined silicone rubber spacers are the best choice for all temperatures.

All Hawach sample vials are manufactured under ISO9001 clean environment, and the unique packaging ensures cleanliness and safety during transportation.

How to prevent debris:
1. Select a PTFE-lined spacer to prevent the spacer material from entering the sample;
2. Almost complete removal of debris using pre-perforated spacers;
3. For highly sensitive samples, we recommend using PTFE lining spacers as the PTFE layer acts as a barrier to chemical corrosion.
The sealing of a sample vial is also an important factor affecting the experimental result.

The polyethersulfone (PES) syringe filter with the feature of low protein binding and has excellent flow rates is mainly used for sterilizing or clarify viscous proteinaceous solutions especially in the life-science applications biological and pharmaceutical labs, this is because of its extremely-low protein binding characteristic.

The filter housing made from Pigment-free and medical grade polypropylene (PP), this makes the filter with wide chemical resistance and PES filter media is not suitable for strong chemicals like Acid and Alkali based samples.

The Hawach filters can be autoclaved at 121℃ at 1 bar for 20 minutes/EO/Gamma. The Hawach PES Syringe Filter is mainly used for Tissue Culture Media, Clarification or Sterile Filtration and HPLC sample preparation, PES FILTER application is suitable for all aqueous based solutions.

PES syringe filters have female Luer lock inlets and male Luer slip outlet connection for standard and easy use with HPLC sample preparation consumables. Easier injection and easier filtration with no unwanted extractable.

Please note the PES syringe filter cannot be used with solutions based on hexane, esters, chloromethane, acetone, or aromatic hydrocarbons, ketones, halogenated, chloroform, and concentrated acids.

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Today, Hawach want to talk about the pre-treatment process for pesticide residue detection from the perspective of food safety – QuEChERS, and also tell you how to pre-treat pesticide residue food.

Introduction

The present analytical methods and determining techniques, pre-treatment processes of samples, and the rapid and easy determination of pesticides remaining in food were hot spots in the field of international agricultural products and food safety. The food safety inspection and supervision institutions have specialized chemical laboratory staff sampling the ingredients on the market every day, to check whether pesticide residues are up to standard.

Principle

Impurities can be removed and purified by means of the interaction between the adsorbent filler and the impurities in the matrix. The principle is similar to HPLC and SPE. Specifically, the sample to be tested is homogenized and acetonitrile extraction and salt extraction is stratified with the help of specific salts. The impurities are combined with adsorbents for centrifugal separation and purification finally.

Operating steps

Pesticide residue detection in food is a process of quantitative analysis of the components in the complex matrix, including sample preparation, purification and enrichment, separation and detection, and comprehensive analysis. Pretreatment includes extraction and purification. Extraction is the process of dissolving and separating pesticide samples. Purification is an adsorption process of adsorbent and impurities to separate impurities and matrix.

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Note on the filter paper box that when using the quantitative and qualitative analysis filter paper to filter the precipitate:
1. Generally uses natural filtration, using the filter paper body and the ability to retain solid particles to separate the liquid and solid;
2. Because the mechanical strength and toughness of the filter paper are small, try to use less filtration to filter. If the filtration speed must be increased, the filtration failure will be prevented to prevent the filtration. When the air pump is filtered, it can be stacked in the funnel according to the pumping force. Put 2 to 3 layers of filter paper, when vacuum filtration, put a layer of dense filter cloth on the funnel, and then filter the filter paper;
3. It is best not to filter hot concentrated sulfuric acid or nitric acid on the filter paper;

The difference between the use of quantitative filter paper and qualitative filter paper is that qualitative filter paper is used for qualitative chemical analysis and corresponding filtration separation; quantitative filter paper is used for gravimetric analysis test and corresponding analytical test in quantitative chemical analysis. The function of the quantitative filter paper is mainly used for the ashing weighing analysis experiment after filtration. The ash weight of each filter paper after ashing is a fixed value, and the qualitative filter paper is used for general filtration.

In addition, under what circumstances are the quick filter paper, medium speed filter paper and slow filter paper used separately? The main components are fibers, namely C, H, O, and a small amount of other elements. However, the ash produced by the quantitative filter paper is seldom, negligible, and is used for quantitative filter paper and qualitative filter paper.

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Bottle-top dispensers use advanced inert materials (silicate glass, ETFE, PFA, FEP, PTFE and platinum-iridium, and PP) to ensure the purity of the reagent from first to last dispensers. In addition, it can also be used for all kinds of range of liquid separation and can also be used for biological tests when autoclaving sterilization.

Bottle-top dispensers include a safety system with a drain line and a safety helmet to prevent accidental dispensers or spills. Slotted drain lines always ensure proper installation and safe operation.

Bottle-top dispensers are easy to use. Use the adjustable capacity control knob. Simply mark the required capacity. Drain valves are easy to clean and replace.

Bottle-top dispensers allow you to change accessories according to your app’s workflow. Fast and easy. There are many sizes of the drain and inlet pipes, which can meet your requirements.

Bottle-top dispenser is a fast, reliable and safe dispensers utility that is compatible with a wide range of liquids and is now used in a wide range of biological, pharmaceutical, clinical, chemical and forensic laboratories.

Features of bottle-top dispensers
1. Accuracy;
2. Repeatability;
3. Durability;
4. Easy operation.

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Cellulose Exaction Thimble

For the cellulose exaction thimble (CET), parameters are mainly focused on the constitution, heating temperature. CET is usually made out of high-grade cellulose or seamless noble cellulose and lines of cotton, excluding any binding elements, which means only 60% high purified poplar fiber and 40% fine cotton fiber are kept inside. The heating temperature is 75°C, and for the formulation is 10°C. Notably, DOP Retention is 99.8% presenting a good retention ability, and the maximum temperature is up to 100°C. It is the consistent high porosity and high fitting accuracy that respectively ensures fast flow through and applies to all available extraction systems.

Glass Fiber Exaction Thimble

Speaking of glass fiber exaction thimble, there are merely three sizes in Hawach– SLGET32120, SLGET2590 and SLGET2870. Even though equipped with different capacities of background response and flow pressure, they possess same maximum temperature, DOP retention(higher than 99.9%), weight loss( less than 0.2m) and composition (super-fine glass micro-fiber).

Comparison Between Two Types
 
Cellulose Exaction Thimble
Glass Fiber Exaction Thimble
Application
General Soxhlet extraction
Indoor dustfall and detection of indoor toxic organic compounds
Soxhlet extraction (Temperature >120°C, strong acid.etc.)
Stationary source monitoring

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Characteristics of QuEChERS

QuEChERS is a pretreatment method for pesticide residue detection. This paper refers to the products produced by our company. Its name comes from the acronyms of the words “Quick, Easy, Cheap, Effective, Rugged, Safe”, which are also the characteristics of the processing methods. The pretreatment method of agricultural residue belongs to the upgraded version of SPE, which has similar purification effect with SPE. However, the process is more concise, time-saving, efficient and economical, which is gradually accepted by the majority of analysts.

Use of QuEChERS

(1) Weighing 10g homogeneous sample into the centrifugal tube.
(2) Add acetonitrile and other extractive solutions, shake violently for 1 minute so that the sample can be fully dissolved in acetonitrile solution.
(3) Adding QuEChERS extraction salt to improve extraction efficiency.
(4) After extraction, the supernatant was separated from the mixture of the sample and acetonitrile.
(5) The mixed solution is added to the purification tube, and the purified solution can be obtained by adsorbing the impurities with the adsorbent in the purification tube.
(6) Take supernatant for instrument analysis to judge whether it meets the standard or not.

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Hawach vacuum filtration device is a kind of equipment which uses vacuum negative pressure as a driving force to realize solid-liquid separation. In structure, the filter section extends along the horizontal length direction and can complete filtering, washing, drying, and regeneration of filter cloth in turn.

The common rubber belt filter equipment on the market has the advantages of high filtration efficiency, large production capacity, good washing effect, the low moisture content of filter cake, flexible operation and low maintenance cost. We will introduce in detail the components of our vacuum filtration as following aspects.

Glass multiply

It mainly consists of glass filter cup, high borosilicate filter head, stainless steel filter support 316L, stainless steel valve, aluminum alloy clamp, dust cover, rubber plug.

Stainless steel multiconnection

It mainly consists of stainless steel filter cup 316L, stainless steel filter head 316L, stainless steel filter support 316L, stainless steel valve, aluminum alloy clamp, dust cover, rubber plug and so on.

Solvent filter

This part mainly consists of triangular hydrops bottle (1L) sand core filter head, filter cup (300ml), fixing clip, dust cap, hose, and hose linker.

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Hawach Scientific mission is to work with our customers to make the world healthier, cleaner and safer. We help our customers accelerate research in the life sciences, solve complex problems and challenges in the analytical field, promote the development of medical diagnostics, accelerate the drug launch process, and improve laboratory productivity.

Hawach multi-channel advanced mechanical pipette is comfortable to use and can play an ideal role in the application of microplate. Color-coded wide finger support and ergonomic handle design can improve your fluid transfer test. The advanced mechanical pipette can be used for single and multi-pass molds. We are leading the way in introducing integrated solutions that combine innovative technologies, convenient procurement and all-around services.
More detail information from info@hawach.com.

Products specification
Single-channel Adjustable Volume
Single-channel Fixed Volume
Eight-channel Adjustable Volume
Twelve-channel Adjustable Volume

Products description
1. Ergonomic comfort
2. Color-coded wide finger-like supports are ergonomic in their identification
3. The design of the handle is soft enough to attach to the shape of your hand
4. Large Ergovisio display, easy to identify capacity

Function
1. Durable handle material
2. Double control liquid transfer button; The rotary button cap at the top prevents accidental volume selection errors.
3. Advanced gear capacity selection mechanism can enhance precision and accuracy
4. Strong blowing force to achieve 50 microns and below the efficient transfer of droplets

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The solid phase extraction cartridges (SPE column, or Solid Phase Extraction Cartridges, or SPE cartridges for short) is a sample pretreatment device for extraction, separation and concentration developed from a chromatography column. Mainly used in sample pretreatment of various foods, agricultural and livestock products, environmental samples and target compounds in biological samples.

Advantages of solid phase extraction cartridges

1. Precise speed control, single flow rate 0.01~7ml/min, support large volume injection and positive pressure elution to avoid cross contamination;
2. Stepless numerical control operation, LED digital display, light touch button, ergonomics mechanical design;
3. Corrosion-resistant roof, chassis phosphating and multi-layer epoxy resin spraying treatment;
4. The chassis structure is convenient to maintain;
5. Multi-channel, small column joints resistant to acid, alkali, organic solvents, oxidant corrosion;
6. Technical motor, using high-precision numerical control technology, low energy consumption, low noise;
7. The CNC pump tube adopts the American original long-life pipe.

Principle of solid phase extraction cartridges

SPE technology can be approximated as a simple chromatographic process. SPE is a separation principle using liquid chromatography using selective adsorption and selective elution. The more common method is to pass the liquid sample solution through the adsorbent, retain the substance to be tested, and then use the appropriate strength solvent to wash away the impurities, and then quickly elute the test substance with a small amount of solvent, thereby achieving the purpose of rapid separation, purification and concentration. It is also possible to selectively adsorb the interfering impurities and let the tested substances flow out; or simultaneously adsorb the impurities and the tested substances, and then selectively elute the tested substances with a suitable solvent.

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All the technique cores of HPLC from Hawach Scientific are focused on the characteristics of the chromatogram column.

Quality Recognition
This is shown as the fact that terminal customers have published more than 500 papers on those journals at home and abroad. For famous oversea journals, there are Science, Journal of Chromatography A, Journal of Agricultural and Food Chemistry, Journal of Pharmaceutical and Biomedical Analysis. etc., while domestic journals mainly involve the area of Fingerprinting Research with over 23 papers and 2 of Characteristic Fingerprinting.
Comparison With Similar Product of A Famous Company
According to test results, HPLC universal-C18 columns of Xchroma series has demonstrated an excellent chromatographic column performance, notably in column efficiency and symmetry, which successively means that Hawach HPLC can substitute similar products from other international brands.
Application Advantage
High column efficiency and large capacity of the peak
Excellent batch stability
High purity and good homogeneity of imported fillers
Multiple Types
Surprisingly, there are various types of only C18 column such as EChorma series (high purity porous spherical silica gel of type B) with a purity of 99.99%.

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Laboratory workers use a membrane to filter two phases. Actually, the membrane is a kind of media. According to different aperture sizes, filter membranes can be divided into the microporous membrane, ultrafiltration membrane, nanofiltration membrane and reverse osmosis membranes. Specifically, the microporous membrane is commonly used in laboratories with an aperture size of 0.1 to 1 micron. Talking about microporous membrane, it is mainly made from refined nitrocotton with moderate cellulose acetate, acetone, n-butyl alcohol, ethyl alcohol, etc. It is important to filter solvent and samples with the microporous membrane in the laboratory, basically, there are two reasonable concerns. One is to protect the chromatographic column and instrument. The other is to prevent pollution from affecting the analysis results. For example, for the ultraviolet detector, if sample concentration is low to a certain degree, the particle will cause serious noise to interfere with normal signals and finally decrease the SNR (Signal to Noise Ratio) and affect the test results.

Choose of Microporous Membrane
PTFE: Apply to all solvent, acid and salt.
Nylon: Apply to the most organic solvent and hydro solvent.
RC: Apply to water-soluble sample and an organic solvent.
PES: Apply to water-soluble sample.

Caution against Using of Microporous Membrane
1. Using a syringe with volume of fewer than 10 ml may cause burst due to high pressure.
2. Different membrane materials will produce different absorption efficiency, but do remember to choose the microporous membrane in accordance with the recommendation in operation specification.

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String wound filter cartridges adopt the most advanced design of inner and outer density, which can increase the impurity and prolong the service life by 20 ~ 40% compared with the traditional life.

The surface of string wound filter cartridges is treated with anti-wool treatment to reduce the production of cotton wool, avoid the release of fiber and ensure the quality of filtration.

Applicable scope of string wound filter cartridges
1. PCB wet process;
2. Electroplating process;
3. Petrochemical process;
4. Chemical process;
5. Beverage industry;
6. Pure water prefiltration;
7. Wastewater recovery.

Features of string wound filter cartridges
1. Advanced diamond thread progressive structure – the larger pollutants are intercepted in the outer layer; the tiny suspended matter is captured by the inner layer.
2. PP fiber material, no foaming, won’t extract organic pollution tank liquid and can keep the liquid clean for a long time.
String wound filter cartridges include filter media, inner core, and o-rings/gaskets, whose filtration efficiency≥80%, outer diameter φ63 / 114mm, inner diameter φ28mm, filtration area 0.4.

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Laboratory data show that the optimum flow rate of silica gel flash columns is decided by the length and width of columns and the property of gel. To be more specific, longer and narrower columns will provide more theoretical plates which are able to affect the flow rate. When referring to the resolution, it is influenced by the stationary phase.

If the stationary phase or the gel which is arranged in the columns is more balanced and with smaller particle size, the silica gel flash columns can provide better resolution. In general, the smaller particle size and the larger superficial area mean higher resolution.

Managing all the factors to optimize the purity of components and the recovery of silica gel flash columns could be very complex because they have a mutual effect. However, different results will be made when in independent testing. In other words, the selectivity of the mobile phase has the most profound effect on separation, but it is also decided by the volume of columns and the selection of solvent.

In fact, before the start of any true experiment, settings of silica gel flash columns need to be tested or calculated. If the data from TLC are available, then the optimal settings can be calculated.

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The sample vials were cleaned according to different contamination levels. Generally, the cleaning method is selected according to the degree of pollution. If the cost is adequate, it is best to use a new one every time.

Solution method of cleaning sample vials:
1. Rinse with running water several times;
2. Put it into a beaker filled with pure water and ultrasound for 15 minutes;
3. Change the water and ultrasound for 15 minutes;
4. Soak in a beaker without ethanol;
5. Finally, take out and air dry.

Every year, a large number of samples of agricultural products (other chemicals, organic acids, etc.) are tested by liquid chromatography, gas chromatography, etc. Due to a large number of samples, a large number of sample vials need to be cleaned in the detection process, which not only wastes time and reduces work efficiency, but also sometimes leads to the deviation of experimental results due to the unsatisfactory cleanliness of chromatographic sample vials after cleaning.

Thus, the cleaning of sample vials is very important for experiments. But the cushion must be replaced with a new one, especially when analyzing pesticide residues, or the quantitative results will be affected.

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Syringe filters are widely used in laboratories. The users do not need to change membranes and clean filters, which can save complex and time-consuming preparations. It is very convenient and easy to operate. They are mainly used in sample pre-filtration, clarification, degerming of particles, liquids & gases and so on. It is the preferred method for filtering small samples of HPLC and GC.

Hawach Scientific is specializing in filtration products for more than 15 years. Our syringe filters are made of extractable free medical grade virgin polypropylene housings, with standard inlet (Female Luer Lock) and outlet ( Male Luer) connections unless others stated. Options include different diameters, membrane types, sterile filters in blister packs for critical applications. The options of membrane types have Nylon, PTFE, PP, Active Carbon in both sterile and Non-sterile, and with or without pre-filter.


Hawach Scientific has two big series of syringe filter as FILTSTAR series and WINSTAR series. FILTSTAR series has full of specification with different diameter and different membrane. The high quality has earned a great reputation from most of clients; WINSTAR series is also loved deeply by some clients because of the favorable price with nice quality. Welcome to login our website: www.hawach.com to learn more.

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A PTFE microfiltration membrane uses special technology to compound e-PTFE microfiltration membrane on various substrates (such as polyester felt, PET, PP non-woven fabric, etc.). The coated material not only maintains the inherent high chemical stability, low friction coefficient, high and low temperature resistance, anti-aging, resisting small particles, but also has incomparable air permeability, water resistance and other characteristics.


Features
PTFE microfiltration membrane is a new “breathable membrane filter” and the best filter material for removing bacteria and dust, because of the following features: high air permeability, low resistance, good filtration efficiency, large dust capacity and high dust stripping rate.
Application
Can not only filter microparticles and isolate bacteria but also maintain high filtration efficiency and low circulation resistance.
Can be made into a variety of filter bags, filters cartridges and syringe filters, widely used for the treatment and recovery of smoke and dust particles in cement, metallurgy, food, coating, petrochemical plastic and other industrial fields.
Absolutely no toxicity at room temperature but at high temperatures they emit toxic gases (around 280 degrees).

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The Knowledge of Qualitative Filter Paper
To determine or identify particulate constituents of a mixture irrespective of the amount present, qualitative filter papers are often used in separating process which requires high purity and consistent performance. They are recommended to use in analytical methods by definition, and we can find different types to meet our needs, such as ash-less qualitative Filter Paper, hardened low-ash filters paper.

Often used in several test methods, the ash-less qualitative filter paper is perfect in many standardized test methods, such as gravimetric analysis and sample preparations. Standard ash-less qualitative Filter Paper does not contain any agents of reinforcement.

With intermediate ash content, hardened low-ash filters papers (ash 0.015%) achieve for the gravimetric analysis and typical sample preparations in the analysis where the instrumental techniques are involved.

The success of filtration in the lab depends on the right choice of filter paper. When you select qualitative filter papers in a wide range of grades for particular filtration, you may concern about the specifications such as particle retention, product appearance, filtration speed, ash content, basis weight, and wet burst.

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Hawach bottle-top dispenser is an instrument for measuring liquid things accurately. It is widely used in biological and chemical fields. The following are 9 suggestions for the use of the bottle-top dispenser.

1. Insert the liquid inlet pipe into the bottle-top dispenser and then tighten the nut.
2. Insert the drainage pipe and tighten it, too.
3. Open the pipe cap, and place the pipe cap under the drainage pipe.
4. Turn the volume of liquid separation from zero to the proper scale.
5. Complete the bottle-top dispenser exhausting process. First, make sure that the drainage pipe is open. Second, lift the piston and then press it. Third, repeat the second step until seeing the bubble is already cleared away.
6. Prepare to separate the liquid after exhausting. When there is always being exhausting, we should check if the suction pipe and other valves are installed correctly.
7. Turn the volume of liquid separation from zero to the proper scale.
8. Press the piston to the bottom, and at the same time turn the knob to zero graduation. Lock the bottle-top dispenser.
9. Complete the liquid transferring process. The experimenter should lift the piston to the highest position stable, and then press it to the bottom of the bottle stable.

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Glass fiber extraction thimbles have been widely used since it was launched in 1974, which are highly efficient filters for collecting dust, acid mist, beryllium, and other harmful substances.

Because of glass fiber extraction thimbles, smoke extraction has been greatly improved.

Conditions of use for glass fiber extraction thimbles
According to reports, glass fiber is heated to above 200 ℃ and then cooled, whose strength would start falling constantly. Fiber is heated to 510 ℃, and then cooled, intensity only keep 35% of the original. Fiber can maintain high strength when heated, but after cooling, its strength is greatly reduced.

During the loading and unloading of the glass fiber extraction thimbles, they will not be subjected to the tearing force, shear, etc., and should not be broken. If gaps, cracks and uneven thickness are found, it cannot be used, so as not to be broken by air flow and cause sampling failure.

Features of glass fiber extraction thimbles
1. High purity borosilicate glass fibers;
2. Temperatures up to 500°C (932°F);
3. Low weight loss, high efficiency, and good strength.

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Brief introduction

The solvent filter device is an important part of vacuum filtration. The filter device has two forms: a single filter bottle or filter combination kit. Single solvent filter bottle or solvent filter combination kits are often used in conjunction with vacuum pumps for a wide range of liquid laboratories.

Composition and classification

In general, the solvent filter device consists of a triangular collection bottle, a filter head, a filter cup, and a fixing clip. Depending on the material, the solvent filter device has two common materials, high-quality glass or 316L sanitary stainless steel.

Two common materials

The glass solvent filter device is divided into single-channel and multi-connected devices. Multi-connected devices are composed of glass filter cup, borosilicate filter head, stainless steel filter bracket 316L, stainless steel valve, aluminum alloy clamp, dust cover, and rubber plug.

The stainless steel only has the multi-connection form, the main component has the entire stainless steel filter cup 316L, the stainless steel filter support 316L, the stainless steel valve, the aluminum alloy clamp, the dust cover, the rubber plug.

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The pipette tip is a consumable that is used to help avoid cross-contamination. In general, there is no problem with using a pipette tip for forward pipetting. However, some pipette tips are not necessarily suitable for some special situations. The design of the partial pipette tip does not fully consider the possibilities of various applications, and does not leave enough space in the tip. So when you need to use a liquid that needs to inhale extra capacity, such as a reverse pipetting, or when the liquid being removed is rich in protein and is prone to foaming, “tragedy” can happen at any time. You may find that the liquid is in intimate contact with the filter element after aspiration. As a result, pollution is still likely to spread. In order to control the risk of contamination caused by “intimate contact between liquid and filter element”, some brands have double filter elements in the tip or a closure mechanism (the filter element is automatically closed when the liquid contacts the filter element, so that the liquid cannot be discharged), but Still can’t change the fact that precious samples are lost. The best option at this point is to purchase a tip that leaves enough space in the tip to ensure that the liquid is protected from contact with the filter element even in special applications.

What is a low adsorption tip?
The accuracy and accuracy of pipetting not only requires matching of the tip and pipette, but also tips that are suitable for liquid properties. We often find a phenomenon in operation that when a standard tip (PP) is used to remove a liquid having a small surface tension (for example, a liquid containing a detergent), it is easy to leave a film on the inner surface of the tip. The reagents and samples used in many DNA and protein assays typically contain a detergent. Therefore, in the experiments of such applications, the case of more liquid residue is ubiquitous. Residues of the liquid can result in inaccuracies and inconsistencies in the pipetting results, as well as loss of some expensive samples. The development of low adsorption tips is a common problem in order to improve liquid residue. Different suppliers use different technologies to produce low-adsorption tips, so they differ in their consistency, hydrophobicity, and chemical resistance. There are two common production processes for low adsorption tips: physical polishing and chemical coating. The former utilizes a polishing technique to treat the surface of the tip, making the surface of the tip very smooth to reduce the residue of the liquid, and more reliably ensuring the safety of the sample. However, the mold during polishing will age during the production process, and the quality of the low adsorption tip cannot be guaranteed. The chemical coating method adds a layer of hydrophobic agent to the surface of the tip, which may present a risk of dissolution and introduce contamination. The safest and most reliable is the low adsorption tip produced by Sartorius using patented technology to help reduce liquid residue and increase sample recovery!

Pipette Tip selection universal standard
1. Look at the material: Select the inert material of the tip to ensure chemical compatibility and avoid dissolution. At present, the most commonly used is pure PP material. The quality of the supplier’s materials has a standard that is easy to judge. Just look at the color of the tip to know. “Colored tips can help you quickly identify its range” – is this really the case? In fact, the more important purpose is to cover the impure material. Impurities in the tip made of recycled plastic are very easy to be perceived by the naked eye, and when added, the impurities are “invisible”, so transparent tips are usually better-looking tips.
2. Look at the appearance: a good quality tip will have a high appearance. They have a smooth surface, no burrs, a flat cut, a uniform shape and no straight bends, so as to ensure that the liquid does not easily remain and obtain a precise pipetting effect.
3. Look at the certificate: If you purchase a nozzle without a heat source, the supplier should provide the certificate for the batch of the product.

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Two factors will be considered generally when choosing the SPE cartridges, which are the selection of adsorbents and the selection of cartridge specification. The proper adsorbents will separate the interfering materials and the target substances better and satisfy the retrieving demands at the same time. And there exists upper limits of the quality of compounds adsorbed by adsorbents. Once the quality of adsorbed compounds exceeds, the target substances will pass over the SPE  cartridge straightly instead of remaining in it.

The selection of adsorbents

Adsorbents should be selected according to the properties of target compounds and substrates. As to the examples, we can choose the adsorbents based on the principle that distinguishes target substances and the major interfering materials.

Specification
Maximum sample size
Minimum elution volume
50mg
2.5mg
125μL
100mg
5mg
250μL
150mg
7.5mg
375μL
200mg
10mg
500μL
500mg
25mg
1250μL
1000mg
50mg
2500μL
Substrates
Target substances
Major Interfering Materials
SPE Cartridges
Soil, Sewage
hydrophobic organic pollutants
Humic substances
C18, SLC
Fruits, vegetables, Chinese medicine, fruits syrup
pesticide residues
Carbohydrates, pigments, organic acids, phenols
NH2、Carbon/NH2
Pesticide residues with weak polarity
 
 
C18
Alkaline drugs
 
 
PCX
Acidic drugs
 
 
PAX
Grease
Liposoluble vitamins, phospholipids, aflatoxins
fat
NH2、PSA
The selection of cartridge specification

After choosing the proper adsorbent, we should choose the proper SPE cartridges with the best specification according to the volume of samples. And if the quality of the compounds to be measured is beyond the limit, the target substance will not remain effectively, and the result of the elution is not good. Therefore, it is necessary to choose the proper specification.
Specification
Maximum sample size
Minimum elution volume
50mg
2.5mg
125μL
100mg
5mg
250μL
150mg
7.5mg
375μL
200mg
10mg
500μL
500mg
25mg
1250μL
1000mg
50mg
2500μL

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1. High column pressure

(1) A buffer salt such as (ammonium acetate or the like) is deposited in the column;
(2) Sample contamination deposition. For this case, use 40~50°C pure water first, and rinse the column at a low speed. After the column pressure is gradually decreased, the flow rate is increased accordingly. After the column pressure is greatly reduced, rinse with normal temperature pure water, then use pure methanol.

Rinse the column for 30 minutes; for the second case, contaminate the C18 column by deposition of the sample, and rinse the column back with pure water, replace with methanol, then rinse the column with methanol + isopropanol (4+6). Rinse with methanol, rinse with pure water, and finally rinse with methanol for more than 30 minutes.

2. Unstable

Cause There is a foreign matter between the gem ball and the valve seat with air or check valve in the system so that the two cannot be sealed. Pay attention to the amount of mobile phase in the treatment work, ensure that the stainless steel filter sinks into the bottom of the reservoir, avoid inhaling air, and the mobile phase should be fully degassed.

If there is a foreign object between the check valve and the valve seat, remove the check valve and put it into the beaker containing acetone for ultrasonic cleaning. Liquid chromatography column troubleshooting method.

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Made of a thin layer of a semi-permeable material, the membrane can separate substances when a driving force is applied. Membrane filtration is a good method to remove bacteria, microorganisms, particulates, and natural organic material.

Before you identify which filter material suitable to use, you should find out the properties of the fluid or gas type which is the key element to achieve the best result of filtration in the lab.

When you are going to analyze the fluid coming through the membrane filter, membranes that have lower extractability and high flow rates can achieve your request best. If you’re working on the left behind on the membrane, or the retentate, membranes with a smooth surface and proper structure will be perfect most for the analytical application.

In both conditions, the nature of your fluid will also play a role in your selection. Membranes with the very high binding of proteins, peptides or nucleic acids are easy to be clogged. It will interfere with the result by removing desired materials from the filtrate or obscuring what you need in the retentate.

Active carbon block filter cartridges have been a household water purifier technology choice. By using mutual attraction force between carbon and carbon, most harmful to the health of the pollutants in the water can be removed.

Features of active carbon block filter cartridges
1. Effectively remove chlorine and improve the taste and smell of water.
2. Effectively remove particles and improve the clarity of the water.
3. Effective removal of more than 160 pollutants in water, including lead, mercury, asbestos, volatile organic compounds (VOCs) and 15 potential emerging pollutants such as some prescription and non-prescription drugs, some new pesticides and herbicides, some flame retardants and plasticizers and other chemicals.
4. Active carbon block filter cartridges can stop pollutants nearly 30 times smaller than the diameter of a human hair, as small as 0.2 microns.

Active carbon block filter cartridges are mainly processed by edible grade adhesives, plus some high-tech processing technology, and after a special processing method, so that its function and effect become more perfect. Thus, active carbon block filter cartridges can set adsorption, filtration, as well as interception and catalysis as one.

Flash chromatography is a kind of fast chromatographic separation mode, which separates substances by using optimized pre-packaged medium and low-pressure columns.


Flash chromatography, which was developed in 1978, is considered to separate by medium and low pressure. And it is a fast and inexpensive technology compared with traditional chromatography, which is widely used in drug research, sample purification and purification of natural products currently. The characteristics of low-cost and simplicity result in its irreplaceable in the separation and purification.

The most used common filler for flash columns is silica gel. But why silica gel is chosen to be the filler?
One of the reasons is the limited choice of fillers using for the chromatographic columns at that time. And another reason is other bonds, such as C8 and C18, are too expensive.
As a consequence, most methods of flash chromatographic application in the literature are developed on using silica gel as the separation substrate. Flash chromatography usually is a normal-phase liquid chromatography technology.
The size of the sample is usually in the milligram level to hundred-gram. The flow rate is 10 mL/min to 300 mL/min. And organic solvents with low polarities, such as hexane and ethyl acetate, are used as the mobile phases.

Compared with numerous precise analytical instruments in the laboratory, sample vial is very small but the most commonly used. How to properly choose and use sample vial and the associated materials is extremely important to the efficiency of the experiment, the process of experiment and the accuracy of experimental data.

If you choose the improper sample vials, some of the following problems may be caused. The volatilization loss of the analytes led by bad sealing. Chromatographic impure peaks produced by mutual effect between solvent and shock insulator. The mechanical damage of automatic sampler. Bad reproducibility of sample injection. Degradation of the sample. Absorption of the sample, etc.

As a result, the following elements must be seriously considered when choosing the sample vials.

Septa
1.PTFE/Silica Gel
It possesses excellent resealing character, chemical resistance of PTFE before puncture and chemical compatibility of silica gel after the puncture. It is recommended to use for multiple sample injection and storage.
2.PTFE/Silica Gel (Pre-Incision)
It provides good ventilation to prevent the vacuum from being produced inside the sample vial so that you are able to achieve excellent sampling reproducibility. It also eliminates jamming of the bottom needle after sampling and possesses a good ability for resealing. It is recommended for multiple sample injection.

Sterile syringe filters are mainly used in the pharmaceutical industry, fermentation, food & beverage, beer brewing, biological products and others. How to sterilize the syringe filter? Generally, Hawach has two methods, ETO sterilization and Gamma sterilization.

The following is some description:
ETO sterilization, namely ethylene oxide sterilization. It destroys the metabolism of bacteria, causes microbial death, and achieves the purpose of sterilization. EO gas is toxic, so the concentration of EO in indoor air must be controlled to be lower than the national standard. The whole process of sterilization takes a long time, which is due to the need for long ventilation to remove EO residues. EO gas is flammable and explosive. It cannot be leaked during storage and sterilization. Safe sterilizers must be selected for safe operation and storage.

Gamma sterilization is by gamma-ray irradiation, the chemical substances (DNA) in microorganisms have changed, resulting in the loss of cell activity, so as to achieve the purpose of sterilization. Gamma sterilization has the advantages of complete sterilization, non-toxicity, no residue, green environmental protection, low energy consumption and energy saving. It can sterilize a large number of products, immediately using after sterilization without waiting. Gamma-ray sterilization requires a certain device to be able to carry out, but also a one-time investment of more capital. After sterilization, the white syringe filter is probability yellowish slightly.

Generally, Hawach syringe filters use Gama sterilization, which requires a certain amount for sterilization, otherwise, additional operating costs will be required; if ETO sterilization is applied, there is no need for quantitative requirements.

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Bonded-phase chromatography is a liquid-liquid chromatography method in which a stationary phase is covalently bound to a carrier particle, which overcomes the mechanical shock in the distribution chromatography, the constant loss of the stationary phase and the gradual change of the nature of the column.

Here we have a Quickstart for filler and model selection based on bonded-phase.

For highly polar samples, use C18, C8, amino, cyano bonded phase silica gel fillers or butyl, octyl, phenyl bonded phase agarose and dextran fillers, or polymer fillers, reversed Separation.

For medium and low polarity samples, normal phase separation or hydrophilic chromatography separation using amino group-containing, diol-based, and surface-modified silica-bonded silica gel fillers.

For high molecular weight samples, size exclusion (gel filtration) is performed with agarose and dextran or silica gel packing.

Specific structural samples, optional filler matrices including agarose and dextran containing metal polymerization, activation coupling, small ligand affinity, antibody affinity, pigment affinity bonding phase, and choral groups, crowns Polymer-bonded phase polymer packing, separated by affinity chromatography.

The ionizable sample, the ion exchange method and the filler matrix were separated and purified by agarose and dextran containing an SP.Q.CM.DEAE bonded phase, silica gel, and a polymer epoxy resin by ion exchange.

At present, the quantitative analysis filter paper produced in China can be divided into three categories: fast, medium speed and slow speed. The white band (fast), the blue band (medium speed) and red band (slow speed) are used as markers to classify the filter paper box. The shape of the filter paper has two kinds: round and square. According to the diameter, the specifications of circular paper can be divided into d9cm, d11cm, d12.5cm, d15cm and d18cm. Quadrate quantitative filter paper has 60 cm x 60 cm and 30 cm x 30 cm.

In addition, the difference between quantitative filter paper and qualitative filter paper is that qualitative filter paper is used for qualitative chemical analysis and corresponding filtration separation, and quantitative filter paper is used for gravimetric analysis test and corresponding analysis test in quantitative chemical analysis.

The quantitative filter paper is mainly used for ashing weighing analysis experiments after filtration. The ash weight of each filter paper after ashing is a fixed value. The qualitative filter paper is used for general filtration.

The main difference between quantitative filter paper and qualitative filter paper is the amount of ash produced after ashing. The main difference between quantitative filter paper and qualitative filter paper is the amount of ash produced after ashing. Qualitative filter paper does not exceed 0.13%, quantitative filter paper does not exceed 0.0009%. Ashless filter paper is a kind of quantitative filter paper, its ash content is less than 0.1 mg, this weight can be neglected in the analytical balance. Note that both quantitative filter paper and qualitative filter paper are concepts of cellulose filter paper.

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Mechanical bottle-top dispensers and electronic bottle-top dispensers for liquid handling are two main types of bottle-top dispensers in Hawach Scientific Co. Ltd with the mini-type instrument.

Bottle-top dispensers in Hawach Scientific Co. Ltd, which is one of the most common instruments in the experiment, are the safest and most convenient liquid transfer devices. They can handle dangerous or toxic solvents such as acids, saline solutions, and organic solvents and are capable of accurate and highly repeatable liquid separation without waste of reagents while providing safety assurance for operators and the experimental environment.

Other services

The pipettes/ bottle-top dispenser in our company both have the verification certificate of “Beijing Institute of metrology and testing”. We can provide you with the operation and guidance of liquid transfer, including the provision of geographical services, intelligent solutions, and suggestions, and support the practical application of knowledge solutions to meet your special needs in the laboratory. Let your progress with confidence.

Cellulose Exaction Thimble

For the cellulose exaction thimble (CET), parameters are mainly focused on the constitution, heating temperature. CET is usually made out of high-grade cellulose or seamless noble cellulose and lines of cotton, excluding any binding elements, which means only 60% high purified poplar fiber and 40% fine cotton fiber are kept inside. The heating temperature is 75°C, and for the formulation is 10°C. Notably, DOP Retention is 99.8% presenting a good retention ability, and the maximum temperature is up to 100°C. It is the consistent high porosity and high fitting accuracy that respectively ensures fast flow through and applies to all available extraction systems.

Glass Fiber Exaction Thimble

Speaking of glass fiber exaction thimble, there are merely three sizes in Hawach– SLGET32120, SLGET2590 and SLGET2870. Even though equipped with different capacities of background response and flow pressure, they possess same maximum temperature, DOP retention(higher than 99.9%), weight loss( less than 0.2m) and composition (super-fine glass micro-fiber).

Comparison Between Two Types
 
Cellulose Exaction Thimble
Glass Fiber Exaction Thimble
Application
General Soxhlet extraction
Indoor dustfall and detection of indoor toxic organic compounds
Soxhlet extraction (Temperature >120°C, strong acid.etc.)
Stationary source monitoring

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Pesticide residues, a word that gives you a sense of damage to health. Every time to pick up fruits and vegetables in the market, do you worry about pesticide residues? But when it comes to health, I’m sure I’m not the only one who CARES! However, QuEChERS detection can help resolve this annoyance.
Set of extraction & purification box
Two kinds of products, extraction box and purification box, are used in the pretreatment of pesticide residue detection—QuEChERS. One kind of product is the set of the extraction & purification box—the combination of extraction and purification, which can get a complete set of experiments

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Vacuum filtration is a method of accelerating the water filtration by taking advantage of the negative pressure created by pumping, applied disciplines of which include materials science and technology, inorganic non-metallic materials, ceramics, and ceramic material technology.

Features of vacuum filtration pump
1. Advanced design, high working efficiency and long service life;
2. No need for any working medium and no pollution;
3. Ideal vacuum degree and high air velocity;
4. The motors provided by ODM;
5. Equipped with thermal power saver;
6. Non-friction membrane body movement, no heat generation, no friction loss;
7. Designed with an automatic cooling and air exhaust system.

Features of stainless steel multi-connection vacuum filtration
1. Easy to disinfect at high temperature, resistant to high temperature and corrosion.
2. Multiple samples can be processed at the same time.

Solvent filter of vacuum filtration
1. High quality glass material;
2. Good pressure resistance;
3. Fast flow and good sealing performance;
4. The size and specification meet the international standard.

Pipettes are routine tools in the laboratory. During the daily use, some methods and precautions have not attracted the attention of users. Hawach combines the experience accumulated in practice over the years and summarizes them for discussion.

1. Set the pipetting volume

Adjusting from a large range to a small range is a normal adjustment method. When the scale is rotated counterclockwise, it can be adjusted from a small range to a large range. It should be adjusted to exceed the set volume scale and then adjusted back to the set volume. This will ensure the degree of the pipettes.

2. Assembly tip

Insert the pipettes vertically into the tip, rotate it a half turn to the left and right, and tighten it. It is highly undesirable to use a pipette to strike the tip. This long-term operation causes the pipette parts to loosen due to impact, which can cause the knob of the adjustment scale to become stuck.
 
 
 

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Hawach solid phase extraction (SPE) cartridges contain polymers, absorbents or silica gel based bonded phase packings. Solutions are passed through by using either gravity or vacuum pressure. It can be mounted on the reservoir and filter tube or configured with vacuum manifold for preparing samples. There are several steps to follow to make sure that the SPE cartridges can be used properly.

1. cartridge conditioning
Condition the SPE cartridge to activate the packing before the sample is prepared. Conditioning solvents and procedure depend on the packing and application. Identify the item number on the packaging accurately prior to the cartridge conditioning. Keep the last used conditioning solvent 1mm higher than the packing level of the cartridge, ensuring the packing stay moist. Repeat the conditioning procedure if the packing dries before the sample is added. But washed the remaining buffer salts away by water from packing first before reintroducing solvents.

2. adding the sample
The samples are then filtered and centrifuged before passing through the SPE cartridge to avoid clogging. If necessary, the pH, salt concentration and organic solvent content of the sample solution can be adjusted. Using a pipette or micropipette to transfer the sample solution accurately at the SPE cartridges can be used properly. Adjusting the flow rates of the solution to an appropriate speed. The flow rate should not exceed 5mL/min in general.

3. washing the packing
If the desired compounds are retained in the packing, wash off unwanted residues with solutions that will not remove the target compounds. Then use the sample solvent to wash un-retained materials from the SPE cartridge. It is generally considered to be aiming to keep the volume of wash solution less than a cartridge volume.

If the desired compounds are un-retained in the packing, use sample solvent to remove any residual desired material from the cartridge. Then complete the elution step as wash step again to finish the extraction procedure.

4.eluting the desired compounds
Using a small volume of a solution elute desired compounds, but leaves behind any impurities not removed in the last step. Collection of eluate as the further prepared sample solution. Keep each aliquot is in contact with the packing for 30 sec. to 1 min is necessary for the best recovery.

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Laboratory workers use a membrane to filter two phases. Actually, the membrane is a kind of media. According to different aperture sizes, filter membranes can be divided into the microporous membrane, ultrafiltration membrane, nanofiltration membrane and reverse osmosis membranes. Specifically, the microporous membrane is commonly used in laboratories with an aperture size of 0.1 to 1 micron. Talking about microporous membrane, it is mainly made from refined nitrocotton with moderate cellulose acetate, acetone, n-butyl alcohol, ethyl alcohol, etc. It is important to filter solvent and samples with the microporous membrane in the laboratory, basically, there are two reasonable concerns. One is to protect the chromatographic column and instrument. The other is to prevent pollution from affecting the analysis results. For example, for the ultraviolet detector, if sample concentration is low to a certain degree, the particle will cause serious noise to interfere with normal signals and finally decrease the SNR (Signal to Noise Ratio) and affect the test results.

Choose of Microporous Membrane
PTFE: Apply to all solvent, acid and salt.
Nylon: Apply to the most organic solvent and hydro solvent.
RC: Apply to water-soluble sample and an organic solvent.
PES: Apply to water-soluble sample.

Caution against Using of Microporous Membrane
1. Using a syringe with volume of fewer than 10 ml may cause burst due to high pressure.
2. Different membrane materials will produce different absorption efficiency, but do remember to choose the microporous membrane in accordance with the recommendation in operation specification.

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Column chromatography is the most primitive chromatographic method, the stationary phase installed in a metal or glass column or fixed phase adsorption on the carrier made of the chromatographic column, the sample from the column head to the end of the column along the direction of separation.

Principle

High-performance liquid chromatography – HPLC, is based on the classical chromatography cited the theory of gas chromatography. HPLC technically changes the mobile phase to the liquid transported under high pressure. Chromatographic columns are filled with a special method of small particle size filler so that the column efficiency is much higher than that of classical liquid chromatography.

Application

HPLC is the most widely used chromatographic method and widely used in almost every field of quantitative and qualitative analysis. The high-performance liquid chromatography system is composed of mobile phase storage liquid bottle, infusion pump, sampler, chromatographic column, detector, and recorder. Its overall composition is similar to that of gas chromatography, but many adjustments have been made for its mobile phase as a liquid.

Feature

The infusion pump of HPLC requires constant and stable infusion volume, and the injection system requires convenient and strict switching. As the viscosity of the liquid mobile phase is much higher than that of gas, in order to reduce the column pressure, HPLC columns are generally thicker and much shorter than gas chromatographic columns.

Hawach filter cartridge is the purification equipment for purifying the original ecological resources and recycling the resources, which has the characteristics of low-pressure difference, strong pollution carrying capacity and long service life.

Features of filter cartridges:
1. Excellent chemical compatibility, suitable for filtering strong acids, strong bases, and organic solvents;
2. Fold-type deep filtration with large membrane filtration area;
3. The low-pressure difference, strong pollution carrying capacity and long service life;
4. Wide filtering accuracy;
5. Clean air, noise reduction, and fuel saving.

The application of filter cartridges:
1. Pharmaceutical industry: pre-filtration of various antibiotics and other pharmaceutical solutions;
2. Food and beverage industry: filtration of wine, mineral water, and drinking water;
3. Electronics industry: high purity water pre-filtration;
4. Chemical industry: filtration of various organic solvents, acids, and lye;
5. Metallurgical industry: filtration of various lubrication equipment and hydraulic system for rolling mill and continuous casting machine;
6. Textile industry: purification and uniform filtration for polyurethane melt in the process of wire-drawing, air compressor protection filtration, compressed gas oil, and water removal.

Filter cartridges mainly include membrane pleated filter, microfiber pleated filter, big pleated filter, small pleated filter, metal filter cartridge, and other filter cartridges.

Column chromatography is one of the most important methods to separate and purify organic compound, and adsorption column chromatography is the most widely used. However, the above method is commonly taken under ordinary pressure. It is slow and time-consuming. When prepare, separate or purify the organic compounds which are photosensitive and oxy sensitive in large doses, rapid elution is extremely necessary. Here we will talk about barometric flash column chromatography.

Principle

During the process of barometric flash column chromatography, exert pressure on the eluting agent in column by filling air. So that the eluting agent will flow faster and the operation time will be shortened.

Instrument

Barometric flash column, pump, filter flask and test tube.

Procedures

1. Choose proper barometric flash column according to the volume of samples which are prepared to be separated. Add a little degreasing cotton, quartz sand and adsorbing agent successively after the column is dried and cleaned up. Cover the upper layer of the adsorbing agent with quartz sand afterward.
2. After the preparatory work is finished, slip the rubber plug with duct into the upper end of the barometric flash column, and connect the other end of the duct to the filter flask with pump. Operate the pump to increase the pressure inside the column and the flow rate of eluting agent is also increased.

Hawach sample vial is relative to the ordinary bottle and composed of amorphous solid obtained from the cooling and hardening of molten material, with good corrosion resistance, heat resistance, wear resistance, electrical and optical properties. In your autosampler work, vials, caps, and septa will fully provide you with the necessary support and assurance.

Septa of sample vials
Sample vials are often fitted with caps and septa. Hawach supply standard-certified automatic septa for vials correspondingly. Ensuring that select the matching septa from Hawach, you will get results that are repetitive and consistent. There are three types of gaskets to match with reagent vials: screw cap septa, crimp cap septa and snap cap septa.

septa and cap for screw thread sample vials
● Screw cap septa material include PTFE and silicone.
● Cap of PTFE has black -8mm color and Blue – 9 mm.
● Septa color: white – silica gel; Red/blue -PTFE; Blue is the pre-payment.

septa and cap for crimp top sample vials
● Clamp cap septa seal better and are more commonly used for GC injection or long-term sample storage.
● 11mm silver aluminum compression cap and 1mmPTFE/ silicone /PTFE septa.
● Septa color: white – silicone; Red/blue -PTFE; Blue is the pre-payment.

septa and cap for snap vials
● Material: plastic
● Color: black, blue, transparent

Multi-function syringe filter is convenient to use for its ingenious structure design. It greatly simplifies the experimental operation steps, improves the work efficiency, and can fully meet the needs of customer sample pretreatment work. All products of syringe filter provided by Hawach have corresponding test reports and qualification certificates. Mainly include the following ones.

●Filter IC test data report of Filstar hydrophilic PTFE
●ICP-MS Test results to a special style of Filstar series with 25mm PES
●Detection results of heavy metal impurities about Winstar Hydrophilic PVDF and Purstar hydrophilic PVDF
●Chemical compatibility of membranes and housing
●Official testing certification of Filter
●Test report of sterilization filter: The test report of the sterilization filter is mainly for the sterilization filter, which is mainly used to explain that the sterilization degree of the sterilization filter is high, and it will not affect the sterilization experiment, that is, it will not introduce other impurity bacteria into the customer experiment
●Chemical compatibility table for filters, membranes: Compatibility refers to whether the solvent used by the customer dissolves the filter/membrane during the filtration process, thus introducing impurities into the customer sample.
Open the following link to see the details of test reports and qualification certificates to the syringe filter: https://www.hawachfilters.com/

In normal phase chromatography, a polar bonded stationary phase is generally employed, and the surface of the silica gel is bonded to a polar organic group, and the name of the bonded phase is determined by the bonded group. The most commonly used are cyano (-CN), amino (-NH2), and diol (DIOL) bonded phases. Therefore, there is a CN HPLC columnNH2 HPLC columnDIOL HPLC column.

The mobile phase generally uses a nonpolar or weakly polar organic solvent having a lower polarity than the bonded phase, such as a hydrocarbon solvent, or a certain amount of a polar solvent (such as chloroform, alcohol, acetonitrile, etc.) to adjust the mobile phase. Elution intensity.

It is commonly used to separate compounds of different polarities, to separate isomers, and in particular to separate different types of compounds.

The separation mechanism of normal phase chromatography is generally considered to belong to the partition chromatography. The distribution ratio K of the component increases as the polarity thereof increases, but decreases as the polarity of the polarity modifier in the mobile phase increases (or increases in concentration). At the same time, the greater the polarity of the polar bonded phase, the greater the retention of the component.

Filter papers are designed for the preparation of samples and gravimetric analysis. Used for quantitative analysis, we have filter papers made of refined pulp and linter with alpha-cellulose content.

As the classic general purpose ashless filter paper with a medium-speed filtering rate, our BIO-40 high-purity quantitative filter papers are suitable for typical applications to include gravimetric analysis for numerous components and for all kind of pre-filtrations.

With a high rate of filtration, wide-pored, soft, spongy structure, extremely low-ash content, our Ltd BIO-41 fast-speed ashless filter paper is particularly suitable for analytical procedures and tests involving large particles or gelatinous precipitates.

With slow filtering rate and fine particle retention, such as our BIO-42 with Particle retention of 2.5μm and BIO-44 with particle retention of 3.0μm, slow-speed ashless filter papers are for typical analytical precipitates such as cold barium sulfate, lead sulfate, zinc and nickel sulfides, etc.

BIO-43 ashless quantitative filter with medium-fast filtration speed and good retention of medium and thick particles is suitable for gravimetric measurements in food and soil analysis, X-ray fluorescence detection, etc..

Points for attentions are as follows:
1. Install the drain pipe and the intake pipe to make the nozzle straight into the valve, tighten the nut, avoid violent installation and insert the nozzle into the valve.
2. Before each use bottle-top dispenser, it is necessary to ensure that the intake and drain valves and all valves are properly installed and tightened to avoid splashing of piston movement.
3. Drainage ensures that the drainage pipe is not directly directed to the operator to ensure safety.
4. When discharging liquid, control the piston to move slowly and uniformly. Use appropriate container to receive the liquid and let it go down the wall.
5. When discharging fluid, stop immediately and do not operate violently in order to avoid further damage to the instrument.
6. After the instrument is used, please fasten the safety cap of the drain pipe to prevent the dropping of the liquid at the outlet of the drain pipe due to gravity or water vapor in the air.
7. After using the bottle-top dispenser, please rotate the calibration adjustment ring to the “0” position to ensure safety.
8. Prohibited reagents: HF acid and bromine suspension. (For use, special bottle mouth separator is required)

Glass fiber extraction thimbles have been widely used since it was launched in 1974, which are highly efficient filters for collecting dust, acid mist, beryllium, and other harmful substances.

Because of glass fiber extraction thimbles, smoke extraction has been greatly improved.

Conditions of use for glass fiber extraction thimbles
According to reports, glass fiber is heated to above 200 ℃ and then cooled, whose strength would start falling constantly. Fiber is heated to 510 ℃, and then cooled, intensity only keep 35% of the original. Fiber can maintain high strength when heated, but after cooling, its strength is greatly reduced.

During the loading and unloading of the glass fiber extraction thimbles, they will not be subjected to the tearing force, shear, etc., and should not be broken. If gaps, cracks and uneven thickness are found, it cannot be used, so as not to be broken by air flow and cause sampling failure.

Features of glass fiber extraction thimbles
1. High purity borosilicate glass fibers;
2. Temperatures up to 500°C (932°F);
3. Low weight loss, high efficiency, and good strength.

QuEChERS is widely applied in testing. Their testing objects include plant products like fruits and vegetables, animal food like chickens and all kinds of high-sugar food after complex processing like cookies and chocolate. The researchers pay attention to the combined use of relative instruments, which develops a variety of testing methods. QuEChERS is widely used in countries mostly because it has three advantages: the good separation, the high fidelity, and the complete purification. They use QuEChERS to purify not only the pesticides but also some other substances. They used it to test the content of isoflavones in the solid beans products at countries.

In China, in the early experiments of QuEChERS, Chinese researchers detected the single pesticide. And the target objects usually are some kinds of carbamate, organic phosphorus and pyrethroids. With technology development, domestic researchers started to study the extraction and purification of grain samples with low water. And in recent years, QuEChERS is applied in the wider range with high developments. They begin to detect traditional agricultural products as well as complex animal products like chicken livers and fish by it. And beyond that, Chinese researchers also use it to testing Chinese medicine and tea with Chinese characteristics.

The working principle of vacuum filtration is to form negative pressure at the outlet of filtrate and use it as the driving force of filtration. The vacuum filtration equipment with intermittent operation is mainly introduced below. This equipment can filter suspensions of various concentrations.

Intermittent operation of vacuum filtration equipment has been developed because of its ability to achieve automated operation. The working principle of this equipment is as follows:

The containers are separated into upper and lower chambers by filter media, which constitutes a simple suction and filtration equipment. The suspension is added to the upper chamber. Under the action of pressure, the filter medium enters the lower chamber and becomes the filtered liquid. The solid particles are intercepted on the surface of the filter medium to form the filter residue.

During the filtration process, the vacuum filtration residue layer accumulated on the surface of the filter medium gradually thickens, and the resistance of liquid passing through the filter residue layer increases, and the filtration speed decreases. When the filter chamber is full of filter residue or the filtering speed is too small, stop filtering, remove the filter residue, and regenerate the filter medium to complete a filtering cycle.

The pipette tip is a consumable that is used to help avoid cross-contamination. In general, there is no problem with using a pipette tip for forward pipetting. However, some pipette tips are not necessarily suitable for some special situations. The design of the partial pipette tip does not fully consider the possibilities of various applications, and does not leave enough space in the tip. So when you need to use a liquid that needs to inhale extra capacity, such as a reverse pipetting, or when the liquid being removed is rich in protein and is prone to foaming, “tragedy” can happen at any time. You may find that the liquid is in intimate contact with the filter element after aspiration. As a result, pollution is still likely to spread. In order to control the risk of contamination caused by “intimate contact between liquid and filter element”, some brands have double filter elements in the tip or a closure mechanism (the filter element is automatically closed when the liquid contacts the filter element, so that the liquid cannot be discharged), but Still can’t change the fact that precious samples are lost. The best option at this point is to purchase a tip that leaves enough space in the tip to ensure that the liquid is protected from contact with the filter element even in special applications.

What is a low adsorption tip?
The accuracy and accuracy of pipetting not only requires matching of the tip and pipette, but also tips that are suitable for liquid properties. We often find a phenomenon in operation that when a standard tip (PP) is used to remove a liquid having a small surface tension (for example, a liquid containing a detergent), it is easy to leave a film on the inner surface of the tip. The reagents and samples used in many DNA and protein assays typically contain a detergent. Therefore, in the experiments of such applications, the case of more liquid residue is ubiquitous. Residues of the liquid can result in inaccuracies and inconsistencies in the pipetting results, as well as loss of some expensive samples. The development of low adsorption tips is a common problem in order to improve liquid residue. Different suppliers use different technologies to produce low-adsorption tips, so they differ in their consistency, hydrophobicity, and chemical resistance. There are two common production processes for low adsorption tips: physical polishing and chemical coating. The former utilizes a polishing technique to treat the surface of the tip, making the surface of the tip very smooth to reduce the residue of the liquid, and more reliably ensuring the safety of the sample. However, the mold during polishing will age during the production process, and the quality of the low adsorption tip cannot be guaranteed. The chemical coating method adds a layer of hydrophobic agent to the surface of the tip, which may present a risk of dissolution and introduce contamination. The safest and most reliable is the low adsorption tip produced by Sartorius using patented technology to help reduce liquid residue and increase sample recovery!

Pipette Tip selection universal standard
1. Look at the material: Select the inert material of the tip to ensure chemical compatibility and avoid dissolution. At present, the most commonly used is pure PP material. The quality of the supplier’s materials has a standard that is easy to judge. Just look at the color of the tip to know. “Colored tips can help you quickly identify its range” – is this really the case? In fact, the more important purpose is to cover the impure material. Impurities in the tip made of recycled plastic are very easy to be perceived by the naked eye, and when added, the impurities are “invisible”, so transparent tips are usually better-looking tips.
2. Look at the appearance: a good quality tip will have a high appearance. They have a smooth surface, no burrs, a flat cut, a uniform shape and no straight bends, so as to ensure that the liquid does not easily remain and obtain a precise pipetting effect.
3. Look at the certificate: If you purchase a nozzle without a heat source, the supplier should provide the certificate for the batch of the product.

Reversed phase C18 SPE cartridges are reversed phase separation that includes a sample matrix (mobile phase) of polar or moderate polarity and a non-polar solid phase. The affinity of adsorbents for solutes is mainly due to their hydrophobicity.

Applicable scope of reversed phase C18 SPE cartridges

Suitable for non-polar to medium polar compounds, such as antibiotics, barbiturates, phthalein, caffeine, drugs, dyes, aromatic oil, fat-soluble vitamins, fungicides, herbicides, pesticides, carbohydrates, and p-hydroxytoluene substituted ester, phenol, phthalic acid ester, steroids, surfactant, theophylline, water-soluble vitamins.

Packing of reversed phase C18 SPE cartridges

Octane and cation exchange resin

Reversed phase C18 SPE cartridges have an important position in the solid-phase extraction. Solid-phase extraction allows impurities to be retained, detecting compounds to pass through. The principle and application of the solid phase extraction column of silica gel matrix (C18) are completely similar to that of the solid-phase extraction column (C8) of the same silica gel matrix.

The force of reversed phase C18 SPE cartridges
Van der Waals force and hydrophobic force
Eluent of reversed phase C18 SPE cartridges
Organic reagents such as acetonitrile, ethyl acetate, and methanol.

1.HPLC column no indication
(1) The pump seal gasket is worn;
(2) A large number of air bubbles enter the pump body. Treatment For this case, replace the gasket; for the second case, use a 50 ml glass syringe to help extract air at the pump outlet while the pump is acting.

2. HPLC column peak fork
(1) The HPLC column is contaminated;
(2) The stigma packing collapses. Treatment For this case, first flush the column with pure water, then replace it with methanol, then rinse the column with methanol + isopropanol (4+6) (the length of the rinse time is determined by the contamination of the sample), and then Rinse with methanol, rinse with pure water, and finally rinse with methanol for more than 30 minutes.

If the peak is still poor after rinsing, consider the second case. For the second case, unscrew the column head and check that the HPLC column packing is indented or collapsed.

Remove the indurated part (contaminated packing), fill in the new packing, drop a drop of methanol, fill the packing, refill, press with a smooth stainless steel rod with the same inner diameter of the column, fill it again, drop the methanol, and then press it again. Once, until it is filled and filled. Rinse the HPLC column head with methanol, wipe the packing on the outer wall of the column, tighten the column head, and rinse with pure methanol for more than 30 minutes.

The mixed cellulose microporous filter membrane generally refers to nitric acid – acetic acid mixed cellulose ester microporous filter membrane, which is used for the filtration of bacteria and particles in connection with water quality, medical oil, lubricating oil, fuel oil, and scientific research laboratories.

Performance of the mixed cellulose microporous filter membrane

It is brittle, easy to fracture, flammable and has an electrostatic attraction. When contact with more than 75% of alcohol, it is easy to expand and dissolve. It is also easy to produce toxic nitric acid and nitrite and other deficiencies in the alkaline solution.

Application of the mixed cellulose microporous filter membrane.

1. The filtration of granule and bacteria, antibiotics, globulin, vaccine serum and tissue culture in the pharmaceutical industry.
2. The mixed cellulose microporous filter membrane can be used for air purification of a semiconductor device, preparation of high purity water, purification of solvent, developer, and so on in the electronic industry.
3. The filtration of the fine particles in the Daily chemical industry.
4. The mixed cellulose microporous filter membrane can be used for drinking water filtration, pond water bacterial filtration inspection in public health.
5. Food industry: the filtration of sterilization and suspended impurities for juice, wine, and oil.

Hawach PP melt blown filter cartridges element is a tubular filter element made of non-toxic and odorless polypropylene particles which are heated, melted, spun, drawn and received. If the raw material is mainly polypropylene. It can be called PP spray filter. It is not only used in large quantities in water purification. It also has excellent chemical compatibility and is suitable for the filtration of strong acids, alkalis, and organic solvents. Strong dirt holding capacity, long service life, and low cost.

1. Production principle and characteristics
The PP melt blown filter cartridges element is a tubular filter element made of non-toxic and odorless polypropylene particles which are heated, melted, spun, drawn and received. It has high cleanliness and no pollution to water quality.

2. Performance
a. Acid, alkali and other chemical agents and organic solvents corrosion.
b. Suitable for a wide range of media, can be filtered in a variety of different media.
c. Can not recoil, regenerate,
d. The low working pressure difference, 0.15-0.3MPa (forward)

3. Technical parameters
a. Filtration accuracy: 1um-100um
b. Filtration efficiency: 95%
c. Working pressure: less than 0.4MPa
d. Working temperature: not higher than 80 °C
e. Flow: 0.3-50T / h

4. Application areas:
a.Pharmaceutical industry: Pre-filtration of various injections, liquids, and injections of bottled water, pre-filtration of large infusions and various antibiotics and traditional Chinese medicine injections.
b.Food industry: filtration of alcohol, beverages and drinking water.
c.Electronics industry: Pre-filtration of pure water and ultrapure water.
d.Petroleum and chemical industry: filtration of various organic solvents, acids, and lye, oilfield water injection filtration.

Flash column chromatography can overcome the defect of ordinary column’s separation. It has the advantages of quick, time saving, high efficiency of separation, simple and practicable. As for samples of 0.01 to 10 grams and the Rf value more than 0.15, they can be quickly separated within 10 to 15 minutes.

Packing

1. The adsorbed stationary phases are normally silica gel and aluminum oxide. The required mesh numbers are 100 to 160 or above 160,
2. The lower of adsorbing agent’s mesh number is, the higher degree of separation will be. However, the elution rate will be relatively slower,
3. When there are great differences between the Rf values, you can load 30 mg/g of silica gel with a mesh number of 100 to 160. In more cases, 10 mg/g of silica gel is required,
4. When using aluminum oxide, the required mesh number is 100 to 150. 20 to 50 grams of aluminum oxide are needed to separate 1 gram of sample.

Conditions and Procedures of Flash Column Chromatography

1. Choose the eluting agent with high separation efficiency on TLC board,
2. Choose an appropriate chromatographic column with silica gel with a mesh number of 230 to 400,
3. After the eluting agent is added, quickly eliminate the air inside the silica gel under the pressure,
4. After sample loading, elute and control the flow rate within 2.0 in/min.

Hawach sample vials are very small but often used compared with some other instruments in laboratories, which are sufficiently related to the efficiency, the process and the data of experiments. Accordingly, it is particularly important to select and use a suitable sample vials.

When the sample vials are not properly selected for the experiments, there may exist a lot of problems. The incorrect sealing of the vials leads to the volatilization and the loss of analyte. The interaction of solvents and spacers produces stray peaks. The improper vials will cause mechanical damage to the automatic sampler. Such problems influence the experiments.

Therefore, we should consider the following three aspects carefully when selecting the sample vials.

01 the septa
The first kind of septa is made of PTFE/silica gel. It is applicable to multiple injections and sample storage. It has excellent re-sealing characteristics. This septa has chemical resistance of PTFE before pierced, and chemical compatibility of silica gel after piercing.

The second kind of septa is made of PTFE/silica gel with pre-incision. This septa provides good ventilation to prevent producing a vacuum inside the sample vial so that we can use the vials to achieve excellent sampling reproducibility. Besides, this septa can eliminate the blockage of the bottom needle after sampling. It is also applicable to multiple injections.

02 the caps
The screw cap is the universal one with good sealing effect, and mount the spacer mechanically without other tools. The jaw cap has aluminum clamp with good sealing effect. It can adapt to the high-temperature experimental environment. The bayonet cap is very suitable for storing powder samples. But its sealing effect is not as good as other caps.

03 the vials
The vials are usually made of glass and have two colors, transparent and color. The glass is universal and acid-resistant. The brown vials is for photosensitive samples.

The housing material of syringe filter uses high-quality sanitary polypropylene. The structure and design of syringe filter are precision and ensure smooth filtration. Meanwhile, the rationalization of inner space and extremely low residual rate of syringe filter reduce waste of samples.

In HPLC analysis, as the particle size of packing material in the chromatographic column is small, it can be easily jammed by contamination particles. As a result, the sample and solvent need to be filtered in advance to remove particles of pollutants and thus protect the instrument. The ion chromatography which is commonly used in the analysis of the environment also requires no import of inorganic pollutants in the pre-filtration of samples. As an important procedure in the process of pre-filtration, syringe filter can be used in the analyses of HPLC and IC.

One of the disadvantages of traditional filters is easy to burst. However, after specially designed, some of the syringe filters are able to bear the burst pressure of 7 bar. Usually, the edge of the syringe filter is with a screw thread to realize slip resistance. In the laboratory, the filter membrane with consistent quality and clear specification are used cooperatively. The former one is to ensure the consistency of the analysis result, while the latter one is to relieve trouble of confusion.

The general chemically bonded phase uses silica gel as a carrier, which has a partitioning effect and a certain adsorption effect. The size of the adsorption depends on the bonding coverage.

The residual silanol groups on the surface of the support are removed by chemical reaction, which is called end capping, capping or covering. The bonded phase formed is called a tail-type bonded phase. The fully encapsulated bonded phase has no adsorption, but strong hydrophobicity is a disadvantage.

The silica-bonded phase is classified into Si-O-C and Si-O-C (siloxane) type according to the type of chemical bond in which the functional group is combined with the carrier. The Si-O-C type bonded phase is damaged due to hydrolysis and has been eliminated. At present, silicone-type bonded phases are often used, and they can be classified into non-polar, medium-polar and polar types according to their polarities.

The octadecyl bonded phase is the most commonly used non-polar bonded phase. The octadecyl chlorosilane reagent and the silanol group on the surface of the silica gel are subjected to a multi-step reaction to produce an ODS bonded phase. Adsorption or partitioning depends on the ODS bonded phase coverage.

Hawach Filter paper is a kind of paper that has excellent filtration property. It does well in water intaking. In experiments, people often use filter paper as a medium to separate the solid and the liquid.

Qualitative filter paper and quantitative filter paper are frequent in labs. The qualitative filter paper is often used to filter the solution which is applicable to those experiments without any numerical calculation. However, the quantitative filter paper is usually for those needing precision calculation like determining residues.

Quantitative filter paper

The pulp used for making quantitative filter paper is treated by hydrofluoric acid and hydrochloric acid and washed with distilled water in the manufacturing process. Those treatments remove the impurity from the paper fiber.

The quantitative filter paper is suitable for the precise quantitative analysis because the ash when burning it is little, which has little effect on the analysis results. And it is usually divided into three types: the fast one, the medium-speed one and the slow one. There are two designs of quantitative filter paper. One is round and the other is square.

Qualitative filter paper

The qualitative filter paper is different from the quantitative filter paper. There will be more residues after burning it. That is the reason why people hardly use it in the quality analysis experiment. And it is used to filter the solutions mostly.

Hawach scientific bottle top dispenser widely used in tissue culture, bacteriology, clinical, scientific research experiments, and other fields.Single independent packing, provide the capacity of 1 ml / 2 ml / 5 ml, 10 ml / 25 ml / 50 ml.

Mechanical Bottle-Top Dispenser

Used for the removal of high viscosity, high density, high volatile solvents in organic synthesis or petrochemical laboratories, especially in the petrochemical industry. Such solutions are difficult to quickly remove for its special properties, and the traditional cylinder is difficult to accurately quantify. Bottle top dispenser is fully capable of handling such a solution.

1. The optional flexible discharge tube with safety handle permits fast and precise dispensing.
2. Fast volume setting, precise calibration design.
3. The smooth and precise piston moves up and down, making the operation easy and comfortable.
4. Drain tube safety cap can avoid contact with reagents, even with gloves may be easy to install or disassemble.
5. Applicable to any reagent bottle in the laboratory.
6. The transparent suction tube is suitable for various sizes of reagent bottles.
7. Strong chemical tolerance
8. Sterilization can be sterilized at high temperature
9. Four models meet and cover 0.5 to 50ml capacity range

Electronic Bottle-Top Dispenser

1. The electronic dispenser can be effectively reduced
2. The human factor interferes in the process of reducing the liquid, which makes the whole
3. The process is accurate and reliable.

Product specification

Mechanical Bottle-Top Dispenser
1. SLMBT001, Volume 0.5-5ml ,
2. SLMBT002, Volume 1-10ml ,
3. SLMBT003, Volume 2.5-25ml ,
4. SLMBT004, Volume 0.5-5ml ,
5. SLMBT005, Volume 5-50ml ,

Electronic Bottle-Top Dispenser
1. SLEBT001 USA plug,100V-220V/50Hz/60Hz
2. SLEBT002 CN plug,100V-220V/50Hz/60Hz
3. SLEBT001 Euro plug,100V-220V/50Hz/60Hz
4. SLEBT001 UK plug,100V-220V/50Hz/60Hz

The extraction thimble is a type of cylindrical element for filtration. Generally, it is divided into filtering cartridges as gas and a liquid medium.

Thimbles of liquid filtering medium are usually installed inside the pipeline. Besides, featuring a conical shape of the filter cartridge is usually, they are also named conical filter cartridge.

Category

Common filter materials of extraction thimble involve wood pulp fiber paper and polyester non-woven fabric, among which the later one can process coating, oil-proof, water-proof and static-proof methods.

Installation Method

There are vertical lifting, inclined installation(according to specific angles) and flange installation .etc.

Characteristic

1. Improve the effective filtering area on a large scale.
2. Confirm a low and stable pressure difference and increase the circulation of air volume.
3. The compact filter element is easy to be installed.
4. Especially suitable for industries of high dust concentration.

Specification

The size of the extraction thimble is frequently referred to overseas imported samples. Hence, the common specifications are 12.75′, 13.84′, and 26′ in height, which after conversion to metric are actually325 * 660 mm and 350 * 660 mm.

Pesticide residues, a word that gives you a sense of damage to health. Every time to pick up fruits and vegetables in the market, do you worry about pesticide residues? But when it comes to health, I’m sure I’m not the only one who CARES! However, QuEChERS detection can help resolve this annoyance.
Set of extraction & purification box
Two kinds of products, extraction box and purification box, are used in the pretreatment of pesticide residue detection—QuEChERS. One kind of product is the set of the extraction & purification box—the combination of extraction and purification, which can get a complete set of experiments.
Extraction box
The extraction box includes a salt package and a 50ml centrifugal tube. Of course, customers can only buy salt packets, and buy the required centrifugal tubes or use the existing centrifugal tubes in the laboratory to avoid high freight.
To sum up, the extraction box of our company has designed two kinds of products to meet the needs of different customers, one is the salt package and the other is the salt package +50ml centrifugal tube.
Purification box
Three types of purification products are designed: single adsorbent, 2ml centrifugal tube containing adsorbent, 15ml centrifugal tube containing adsorbent.

Vacuum filtration is a technique which could separate the solid from the liquid. The following steps could keep everything running normally:

First of all, put the filter paper into the Buchner funnel and try to make an accurate match. If the diameter of the filter paper is too large, cut it to the proper shape by scissors.

Second, put the rubber plug on the flask opening. There should be a hole in the center of the plug so that the funnel could get into the flask closely and safely in case hitting the glass.

Third, put the funnel into the plug. Otherwise, put them together as an entity and then connect it to the flask.

Then, use the rubber tubing to connect the side nozzle and the vacuum pump.

Next, pour the mixture of the solid and liquid into the Buchner funnel through the filter paper.

Finally the solid would be extracted while the liquid would be sucked into the flask underneath by the vacuum.

This technology could also be applied in syntheses to produce the solid in the reaction or analysis including the gravimetric analysis of suspended solids.

How do we correct the pipette when using it to avoid errors and affect the accuracy of the experiment?

1. For liquids with large concentrations and viscosities, errors will occur. To compensate for the error, the amount of compensation can be determined by experiment. The amount of compensation can be set by changing the reading of the reading window with the adjustment knob.

2. The pipette can be calibrated by weighing the weight of the purified water and calculating it using an analytical balance. Note: 1mL of distilled water weighs 0.9982g at 20°C. Do not rotate the button out of the range within the pipette range. Otherwise, the mechanism will be stuck and the pipette will be damaged.

3. When setting the range, please note that the number is clearly displayed in the display window and rotated to the required range.

4. Do not use a large-scale pipette to remove a small volume of liquid, so as not to affect the accuracy. Also, if you need to remove a larger amount of liquid outside the range, use a pipette.

Solid phase extraction (SPE) is to use adsorbent to absorb the target compound in the liquid sample, separate it from the matrix and interfering compound of the sample, and then elution with eluent to achieve the purpose of separation or enrichment of the target compound.

SPE generally includes four procedures (adsorbent activation, sampling, leaching, and elution). A suitable adsorbent can adsorption first target compounds and cleared off other interfering compounds.

Features of SPE
1. Rapid separation, purification, and concentration;
2. Can selectively adsorb interfering impurities;
3. High purity and concentrated separation can be obtained;
4. Improved detection sensitivity.

Separation modes of SPE
1. Reversed-phase, such as C18, C8, C4, C2, phenyl and so on;
2. Positive phase, such as silica gel bonding -NH2, -CN, -Diol and so on;
3. Ion exchange for extraction and separation of charged analytes.

Application of SPE
1. Detection and analysis of serum, body fluids and liquid drug components in medicine;
2. Detection of pesticide residues in vegetables and fruits in food;
3. Detection and analysis of organic matter in atmospheric surface water and soil in the environment.

Plunger piston sealing rings are divided into normal phase and reversed phase. The reversed-phase sealing ring is with the color of black and made of graphite. Normal phase sealing ring is orange and made of polyethylene, and it is more suitable to the normal phase solvent. Generally, the liquid chromatograph is equipped with a reversed-phase sealing ring. When normal phase is applied, the sealing ring should be changed into a normal phase.

HPLC plunger piston sealing ring is covered on the plunger rod and used for isolating the pump from the outside. When working, the ring rubs with the rod frequently, and it will be frayed after a period of time. As a result, the plunger piston sealing ring should be changed regularly to ensure of airtightness of the system.

You should check if there is a scratch on the plunger rod when changing the sealing ring. Because scratch will lead to slight leakage and reduce the service life of the sealing ring.

Saline solution has a great influence on the service life of sealing ring. If the saline solution is used as the mobile phase system, you should pay attention to the wash of solution channel. Moreover, the saline solution cannot be kept in the pump after HPLC stops working.

Plunger piston sealing rings are divided into normal phase and reversed phase. The reversed-phase sealing ring is with the color of black and made of graphite. Normal phase sealing ring is orange and made of polyethylene, and it is more suitable to the normal phase solvent. Generally, the liquid chromatograph is equipped with a reversed-phase sealing ring. When normal phase is applied, the sealing ring should be changed into a normal phase.

HPLC plunger piston sealing ring is covered on the plunger rod and used for isolating the pump from the outside. When working, the ring rubs with the rod frequently, and it will be frayed after a period of time. As a result, the plunger piston sealing ring should be changed regularly to ensure of airtightness of the system.

You should check if there is a scratch on the plunger rod when changing the sealing ring. Because scratch will lead to slight leakage and reduce the service life of the sealing ring.

Saline solution has a great influence on the service life of sealing ring. If the saline solution is used as the mobile phase system, you should pay attention to the wash of solution channel. Moreover, the saline solution cannot be kept in the pump after HPLC stops working.

A PES ultrafiltration membrane is a common ultrafiltration membrane and the world’s advanced microporous filter membrane. Most of its solutions can provide excellent performance for the purpose of retention and recovery.

PES ultrafiltration membrane is characterized by non-hydrophobic or hydrophilic interaction, low pollution, wide fluid range and pH range, which is usually the preferred ultrafiltration membrane in the ultrafiltration process.

Features of PES ultrafiltration membranes
1. Unique hydrophilic properties;
2. Free of surfactant and surface lubricant;
3. Provides a high level of filtration accuracy and fluxes for the filtered solution;
4. Good strength and resistance to forward and reverse pressure impact;
5. Low adsorption and high retention of protein and precious biological agents;
6. Excellent chemical resistance and thermal stability.

Application of PES ultrafiltration membranes
1. Sterilization of pharmaceutical and biological products;
2. Sterilization and filtration of drinking water, beverages, alcoholic drinks, and other liquids;
3. Terminal filtration of high purity water, ultra-pure water, and deionized water;
4. Purification and filtration of various chemical materials.

PES ultrafiltration membrane cannot be used for the filtration of ketone, ester, oil and other polar solution.

The improper use of chromatographic columns will make the columns decrease or lose effectiveness.
Generally speaking, the columns always have problems at the end of them. If we can install a short column with the same stationary phase as the analysis column in front of analysis column, which is about five to thirty millimeter, the column will have a longer lifetime. Although the effectiveness with a short protective column is less, the final result is worthwhile.
The chromatographic columns’ lifetime usually can reach two years and more when used correctly. One kind of the columns that are based on silica gel only can be used in pH values ranging from two to nine. Some adsorptive substances will be retained on the top of the column, especially some colored substances after used for a long time. For the new columns, the filler at the top of the columns may decrease and collapse, which reduce the column efficiency. And under this circumstance, the experimenters can restore the efficiency of the columns through adding fillers. 
It is better to rinse the columns with eluent with strong eluting power after each work. When hydrochloric acid buffer solution is used as mobile phase, salt-free mobile phase is used to rinse. The compounds containing halogen family may corrode stainless pipes. It is inappropriate to be exposed to them for a long time.

Quantitative filter paper or qualitative filter paper, it is a question.

While at the very beginning, we can distinguish from the literal meaning between quantitative and qualitative.

Quantitative refers to fixed quantity, more about physical properties. Qualitative refers to fixed quality, more about chemical properties.

Most impurities were removed by hydrochloric acid, hydrofluoric acid, and distilled water during fabricating quantitative filter paper. So, the effect of filter paper quantity can be neglected. This characteristic benefits ashing weighing analysis experiment after filtration also called gravimetric analysis test and corresponding analytical test in quantitative chemical analysis,

Hawach has 3 kinds of quantitative filter paper according to its filtration speed, fast, medium and slow. 3 kinds according to impurity content, that is, ashless grade (Ash Content 0.007%), hardened low ash (Ash Content 0.015%), hardened ashless (Ash Content0.006%).

Qualitative filter paper usually was added in a small amount of chemical stabilizer to increase the bursting resistance, therefore be stronger and more durable during the test. But pay attention to Kay nitrogen test, cuz nitrogen in the stabilizer will has an effect on the result.

Still not sure, come consult info@hawach.com!!!

Reversed-Phase Principle
The reversed-phase filler is a kindly of nonpolar filler such as C4, C8, C18 aliphatic chain which is bonded on the silica gel. Nonpolar or hydrophobic compounds are strongly reserved, while polar samples are weakly reserved and go through the flash reversed-phase column faster. The chromatographic process of “reversed-phase” is just the opposite of normal-phase chromatography.

The Selection of Mobile Phase
Commonly we use water and acetonitrile or water and methyl alcohol as mobile phase, and occasionally we also use water and butylene oxide.
We normally will add some weak acid or weak base into the aqueous phase to turn the whole system into acidic or alkaline. This will make sure that the component can reach the peak. The weak acid or weak base we normally use is methanoic acids, trifluoroacetic acid, ammonium hydroxide, ammonium hydrogen carbonate, etc. The percentage is always the same as the liquid system.

The Load of Reversed-Phase Samples
Commonly we use liquid-phase for wet loading of reversed-phase samples. The solvent we normally use is water, methyl alcohol, butylene oxide, methyl cyanide, NN- dimethylformamide, dimethyl sulfoxide, etc. It is better to choose the most suitable solvent to dissolve, and 100 ml of solvent are best for 100 mg of samples.

The filter paper has good filtration and absorption performance and considerable compressive strength. It is suitable for filtering industrial organic suspensions such as petroleum, chemical products, and industrial oils to separate solid and semi-solid impurities. At present, filter paper sold in the market mainly includes quantitative analysis filter paper, qualitative analysis filter paper, and chromatography qualitative analysis filter paper.

Chromatographic qualitative analysis filter paper is mainly used as a carrier in paper chromatography. There are two kinds of filter paper for qualitative separation and chromatography qualitative analysis of the substances to be measured, one is No. 1 and the other is No. 3. Each kind of filter paper can be divided into three kinds: fast, medium and slow.

The pore size of the qualitative filter paper is irregular. Generally, the pore size of qualitative filter paper is large and the quantity is small. You can try a quantitative filter paper. The filter speed and aperture are different. Generally, the aperture of qualitative filter paper is large and there is no strict regulation. Quantitative filter paper can be divided into three types: fast, medium and slow. Its aperture is about 80-120 micron, 30-50 micron, and 1-3 micron, respectively.
 
 
 

It is critical to identify any failure and properly maintain the bottle-top dispenser because it directly contacts with chemical reagents; otherwise, data precision will be greatly affected and safety accidents may even occur.

Identification of tightness failures

Most failures are related to tightness, so leakage tests are necessary to maintain excellent performance of dispenser. Following two test means are recommended:
1. Set dispenser to the largest capacity, take liquid with a sucker and then take the sucker out from liquid; 15s later, check if any liquid drops from sucker;
2.Monitor leakage based on pressure variation by vacuum leakage test.

Routine maintenance and precautions
1. Clean dispenser and accessories such as handle, sealing ring, O ring, and piston, pipelines with deionized water regularly as specified;
2. Replace sealing ring and O ring immediately in case of any crack or leakage;
3. Never face to any part of dispenser directly when disassembling for cleaning or maintenance or discharging liquids;
4. Never spill any solvent reagent onto the surface of dispenser, or clean it immediately;
5. Keep dispenser and accessories clean after use.

Non-Polar Interaction, the interaction between a non-polar functional group on a target compound and a non-polar sorbent, which is better reflected in a polar solvent environment, especially in a water environment. Also known as hydrophobic interactions, such as the interaction between phthalate compounds and C18 in aqueous environments.

Polar interaction, the interaction between the polar functional group on the target compound and the polar functional group on the adsorbent. Polar interactions include Hydrogen Bonding, Dipole/Dipole, Induced Dipole/Dipole, π-π (Pi-Pi) and many other interaction forces. This force can be better reflected in a weakly polar or non-polar solvent environment.

Ion Interaction refers to an attraction force (known as Coulomb force) between target compounds with a positive/negative charge and absorbents with the opposite charge.

Secondary Interaction, for reversed-phase silica bonds and adsorbents, the residual silanol groups on the surface of the particles will interact polarly with polar compounds, and some of the silanol groups will undergo ionic interaction with basic compounds after dissociation.

These forces are secondary to non-polar interactions and therefore are referred to as secondary interactions. Secondary interactions are undesirable for reversed phase silica sorbents and can usually be eliminated by the End capping technique;

Depending on the packing of the HPLC column. The following column types are available on the market:

1. Silica gel HPLC column: Silica gel is the earliest chromatographic column packing used in liquid chromatography. It has a wide range of applications. However, it can only be used under the condition of pH 2.0-7.5, and the use temperature must be less than 60 degrees.

2. Chemically bonded stationary phase HPLC column

2.1 Non-polar bonded HPLC columns: the most widely used HPLC columns C1 to C22. Among them, C18 is the most commonly used non-polar reversed-phase column, and it has a wide range of applications. And the separation effect is good.

2.2 Polar-bonded HPLC column: commonly used amino (NH2) HPLC column, cyano (CN) HPLC column, diol group (DIOL), ion HPLC column

2.2.1 The selectivity of the amino column first appears as a strong hydrogen bonding ability, then in the acidic medium, the weak anion exchange, the tertiary amine and the hydroxyl of the grain interact, using acetonitrile: water system It is possible to separate a flash monosaccharide, a disaccharide, a polysaccharide, and the like.

2.2.2 The separation characteristics of the cyano column are similar to those of the silica gel HPLC column, but the polarity is relatively weak. The advantage is that the gradient elution or the composition of the mobile phase changes rapidly.

2.2.3 The diol-based bonding HPLC column is generally a hydrolysis product of a glycerol-oxypropylsilane-bonded phase, which has a good separation effect on organic acids and certain high polymers and can also be used for the water volume of certain proteins. Chromatography.

3. Polymer ball column.

4. A column coated with a polymer.

5. A column of a particulate porous carbon filler.

6. According to all the carrier materials are divided into three types:
(1) Silicone type: high mechanical strength, easy to make small particles, high theoretical plate number.
(2) Polytype: stable over a wide range of pH values.
(3) Hydroxyapatite type: It has special selectivity for biopolymer samples such as proteins.

7. Divided according to the separation method:
(1) Normal phase: SIL–phospholipid, NH–sugar, vitamin E, CN–steroid hormone.
(2) Inversion: ODS (C18), (C8 CN TMS Pheny1) low molecular weight compound.
(3) Ion exchange and the like.

8. Classified by size:
(1) Preparation: 30 mm 50 mm inner diameter, semi-prepared: 20 mm inner diameter.
(2) Analysis: Standard column: 4-8 mm inner diameter.
Flash column: 3 mm inner diameter, 5 cm long, 4.6 mm inner diameter.
Small aperture column: 2.5mm inner diameter, micro-aperture column 1mm inner diameter.

1. To protect the life of the filter, use the same size filter paper or crepe cloth on the filter to prevent the filter from rupturing.

2. As the determination of the bubble point: the determination of the bubble point pressure can reflect the pore size of the sterilized microporous membrane, which is closely related to the quality of the filtered liquid and is also a guarantee of the quality of the sterilized microporous membrane. An important means.

3. The sterilized microporous membrane should be immersed in water for injection for about 1 hour in water for about 1 hour. The water should be poured out and then soaked in warm water for use overnight. When it is used, it should be taken out and rinsed with water for injection. It can be loaded into the filter for use and installation. Prevent the membrane from leaking.

4. The aperture is cone-shaped, the smooth one side has a small aperture, the rough side has a large aperture, and the front side (glossy side) faces up, and the reverse side (dark side) faces down, otherwise it is easily blocked by impurities. , affecting the filtration rate.

5. When the temperature is low, the treated filter should be immersed in the same injection water as the temperature of the liquid for 5-10 minutes to avoid the cracking caused by the temperature difference.