c18 column Articles

  • C18 extraction of atrazine for increased sensitivity in the RaPID Assay

    Performance of an increased sensitivity method utilizing an extraction and concentration step to increase analyte concentration of the assayed sample is presented. Recently, Shepard and Carr (1992) reported a method for increased detection of atrazine by gas chromatography using C18 solid-phase extraction (SPE) with a 10 mL water sample. An application with BakerbondÒ C18 SPE columns for ...


  • Fast LC/MS/MS Quantitation of N-Methyl Carbamate Pesticides in Food Using Bond Elut™ Plexa™ and Pursuit™ XRs C18

    AbstractA fast quantitation method for the analysis of N-methylcarbamate pesticide residues in vegetables and grainshas been developed with Bond Elut Plexa clean-up, Pursuit XRs C18 columns, and 320-MS LC/MS/MS. Highrecoveries were obtained for most carbamates screened in all matrices tested at 1 ppb levels. Good linearity of thecalibration curves was observed for all analytes, over ...


  • Fast LC-MS-MS Quantitation of N-Methyl Carbamate Pesticides in Food using Bond Elut® Plexa™ and Pursuit® XRs C18

    A fast quantitation method for the analysis of N-Methyl Carbamate pesticide residues in vegetables and grains has been developed with Bond Elut Plexa clean-up, Pursuit XRs C18 columns, and 320 LC-MSMS. High recoveries were obtained for most carbamates screened in all matrices tested at 1 ppb levels. Good linearity of the calibrationcurves was observed for all analytes, over the range from 1 ppb ...


  • USLC columns put the right tools in your LC method development toolbox

    Understanding Selectivity in Reversed Phase Separations – A Simplified Approach to HPLC and UHPLC Column Selection The most significant influence on chromatographic peak separation, or resolution, is column selectivity. Unfortunately, column selectivity is also the least understood and most underutilized parameter. To improve selectivity, method developers often concentrate on ...


    By Restek Corporation

  • Analysis of Polychlorinated Biphenyls in Fish Oil Using Supelclean EZ-POP NP, Silica Gel SPE, and an SLB-5ms GC Column

    Polychlorinated biphenyls (PCBs) were once widely used in many industrial and commercial applications such as insulating fluids, dielectrics, and lubricants. This included their extensive use in electrical transformers. PCB use has been banned in many countries, and the Stockholm Convention currently prohibits their production and use ...


    By MilliporeSigma

  • Analysis of the Pesticides Carbaryl, Diuron, and Propachlor

    Application Report 208: Analysis of the Pesticides Carbaryl, Diuron, and Propachlor Using Ascentis™ C18 This application demonstrates the suitability of the Ascentis C18 for efficient separation of the pesticides carbaryl, diuron, and propachlor. The analysis is carried out using a 15 cm x 4.6 mm I.D Ascentis C18 column under isocratic ...


    By MilliporeSigma

  • Why Biphenyl should be your first choice in LC.. A perspective from a “ GC” specialist..

    Being in GC for 38 years it made me wonder why in LC mostly C18 columns are used for developing a method. I never understood this as its against the basic rules for selecting the optimal stationary phase. In LC we see that about 95% of the applications is done using reversed phase materials, especially the C18 type. There are many C18 types available, and they all show a different separation ...


    By Restek Corporation

  • Rapid HPLC Analysis of PAH Compounds, Using Porous 3µm Particles

    Polynuclear aromatic hydrocarbons (PAHs) are a severe environmental hazard with a variety of sources. Airborne particles, combustion products, and fossil fuels all contain these toxic aromatic substances. Analysis by gas chromatography (GC) has been problematic because GC phases do not meet the need for shape selectivity in separating PAHs. Conversely, high-density C18 octadecylsilane (ODS) ...


    By MilliporeSigma

  • Carbonyl Sampling and Analysis by HPLC

    Sampling of Carbonyls Using a Dual-Layer LpDNPH Glass Sampling Tube and HPLC Analysis with an Ascentis Express C18 Column The dual-layer LpDNPH ORBO-555 tube is an effective sampler for measuring airborne carbonyl concentration. The low background levels in the sampler allow for accurate measurements of low concentration samples or samples collected in ...


    By MilliporeSigma

  • Sorption and desorption of alcohol sulfate surfactants in an agricultural soil

    Alcohol sulfates are one of the most important types of commercial anionic surfactants and may pose serious environmental problems. The present study examines the sorption behavior of alcohol sulfates in an agricultural soil using a batch reactor and column experiments. Kinetics and equilibrium isotherms of the sorption/desorption processes of alcohol sulfate homologues: AS‐C12, AS‐C14, AS‐C16 ...


    By John Wiley & Sons, Ltd.

  • Detection of PPT levels of atrazine in drinking water

    MATRIX: Drinking Water ANALYTES: Atrazine LIMIT OF DETECTION: 5 ppt RANGE OF DETECTION: 5 to 500 ppt MATERIALS: Atrazine RaPID AssayÒ Kit and Sample Diluent Reagents: atrazine control (preparation described below), methanol and ethylacetate (pesticide grade) and distilled or deionized ...


  • Chromatography Tips

    No.1 Gas Chromatography Tips  Our Founders and engineers of the company had accumulated more than 60 years experience in the research and development of HPLC instrumentation; HPLC column technology; mass spectrometer installation, training and services; chemical and biochemical separation, detection and quantification, Proteomics and cancer biomarker research and ...


    By AcuTech Scientific Inc.

  • Complexation Of Mercury(II) In Municipal Wastewater: Insights For The Fate Of Mercury In Effluent-Receiving Waters

    This paper summarizes previous research investigating the chemical speciation of mercury (Hg) in municipal wastewater effluent. Effluent samples were collected from treatment plants in Northern California. The chemical speciation of Hg(II) in these samples was compared to model solutions containing known Hg-ligand composition. Competitive ligand exchange-C18 solid phase extraction was used to ...

  • A high-resolution reverse-phase liquid chromatography method for the analysis of mycosporine-like amino acids (MAAs) in marine organisms

    Mycosporine-like amino acids (MAAs) are a group of about 20 structurally related water-soluble compounds, widely distributed among freshwater and marine organisms. To provide a better assessment of the diversity and concentration of MAAs in aquatic environments a high-performance liquid chromatography (HPLC) method of analysis based on reverse-phase C18 column and trifluoroacetic acid and an ...


    By Springer

  • The Clog Blog

    Clogging and over pressuring are definitely problematic for Liquid Chromatography columns. Back in 2005 John Dolan’s sage advice to chromatographers to make an LC column last forever was simple, “Never open the box!” As John pointed out, this is not practical and I have to agree. But as an LC column manufacturer I have seen remarks from customers regarding clogging as though it ...


    By Restek Corporation

  • Effective Use of the ACQUITY QDa Mass Detector with Your LC: A Q and A with Dr. Tom Wheat

    I recently presented a webinar describing some techniques and tools used for effectively using the QDa Mass Detector with liquid chromatography systems. Several attendees submitted questions that may be of general interest to a broader audience. It is better, as you said, to use negative mode for ...


    By Waters Corporation

  • Fluorophenyl LC Phases- what you should know

     They may be called PFP, PFPP, pentafluorophenyl, fluorophenyl or F5 phases. What they all have in common is the structure shown above (the pentafluorophenyl  group) attached to the silica particles. Most modern phases contain a propyl spacer between the above group and the silica, so that the phase looks something like this: ...


    By Restek Corporation

  • Comparing pesticide residues in Amish and commercially grown strawberries and spinach using QuEChERS, Various dSPE Sorbents, and GC-TOFMS

    Abstract QuEChERS extraction, dSPE cleanup, and GC-TOFMS analysis were used to assess pesticide levels in strawberries and spinach from both commercial and Amish growers. Various dSPE cleanup products were compared to determine which were most effective. Good recoveries were obtained for most pesticides; however, low recoveries were observed for some base-sensitive or planar compounds. ...


    By Restek Corporation

  • LC/MS/MS analysis of metabolites of synthetic Cannabinoids JWH-018 and JWH-073 in Urine

    Abstract A liquid chromatographic method was developed to resolve a comprehensive set of metabolites of JWH-018 and JWH-073. In addition to the chromatographic analysis method, an extraction method was developed to recover a broad range of synthetic cannabinoid metabolites, including carboxylic acid metabolites that are not traditionally recovered using a high pH liquid/liquid extraction. ...


    By Restek Corporation

  • The impact of Toxic Substances Control Act nomenclature on the commercialization of biobased chemicals

    Regulatory Review is a regular column featuring updates on regulatory matters concerning oils- and fats-related industries. Moving from bench to market Many small companies or those new to chemical manufacturing are not aware of their obligations under TSCA. Most biobased chemical companies have likely operated under the research and development (R&D) ...


    By Bergeson & Campbell, P.C.

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