preparative hplc Articles

  • Method Scaling in Preparative HPLC: Analytical Method & Preparative Method

    VOC:  “I tried to scale up my analytical HPLC method to prep and it didn’t work.” Andy:  This is one of the most common things we hear from chemists wanting to do preparative chromatography. We also hear the following question pretty often too: VOC:  “I have a good analytical HPLC method, how do I scale it to ...


    By Waters Corporation

  • What can I use to filter my mobile phase?

    If you are using mobile phase that contains salts or, generally, any components that are weighed out for its preparation, you will need to filter the solution before using with HPLC or UHPLC. The most common type of filtration is membrane microfiltration. We sell an extensive group of products for this and they are discussed very well in a blog ...


    By Restek Corporation

  • Tips to maintain your HPLC & UHPLC systems and columns

    Recently, Ade Kujore (Cecil Instruments), Tracie Brombos (GenTech Scientific) and I were asked by Angelo De Palma, a well-respected writer for Lab Manager magazine, to contribute to an article about maintaining and caring about your laboratory instruments. Here are my tips/best practices for column and HPLC/UHPC/UPLC system maintenance. Maintaining your ...


    By Waters Corporation

  • Aflatoxin & ochratoxin sample preparation columns

    Simultaneous Analysis of Aflatoxins and Ochratoxin A - Sample Preparation Aflatoxins and Ochratoxin A are produced by fungi, e.g. Aspergillus and Penicillium species. Therefore both toxin types are found together in many foods and animal feeds, e.g. cereals. Thus it is appropriate to analyze one extract for the occurrence of both mycotoxins in a single step. A significant assistance ...


    By Pickering Laboratories, Inc.

  • Solid Phase Extraction of Pesticides from Fruits and Vegetables, for Analysis by GC or HPLC

    Recovery rates for polar analytes, including carbamate and thiourea pesticides, are higher and less variable with ENVI-Carb carbon-based solid phase extraction tubes than with C8- or C18- silica-based tubes. Independent investigators found ENVI-Carb tubes to be an effective part of sample cleanup for more than 200 organochlorine, organophosphorus, nitrogen-containing, and carbamate pesticides, ...


    By Sigma-Aldrich Co., LLC

  • SPE Cleanup of Wheat Extracts Prior to the HPLC Analysis of the Mycotoxin Deoxynivalenol

    Deoxynivalenol (DON) is a mycotoxin produced by the Fusarium fungal species graminearum and culmorum. These Fusariumfungi infect cereal crops primarily in wet conditions when temperatures range from 15–30 °C, resulting in grain head damage and DON contamination ...


    By Sigma-Aldrich Co., LLC

  • Analysis of Voglibose in pharmace utical formulat ions by HPLC with post-column derivat izat ion

    Voglibose is an Alpha-Glucosidase inhibitor widely used for the treatment of diabetes. Alpha-glucosidase inhibitors are agents that delay the glucose absorption at the intestinal level and thereby prevent sudden surge of glucose after a meal. Vogilbose is the safest and most effective drug of its class. Since Vogibose has no UV chromophore, post-column derivatization is employed to produce a ...


    By Pickering Laboratories, Inc.

  • Multi-residue mycotoxin analysis single run analysis of deoxynivalenol, aflatoxins, ochratoxin a, zearalenone and fumonisin by HPLC and post-column derivatization

    Although Aspergillus (Aflatoxins, Ochratoxin A) are generally associated with peanuts and Fusarium (Deoxynivalenol , Zearalenone) with wheat, these fungi and those that produce other toxins are not host selective and so can cross plant species. This situation is complicated by the fact that the microscopic mold may not be visible to the naked eye. Also, when infected grains are processed, any ...


    By Pickering Laboratories, Inc.

  • Preparation of thiabendazole standards for use in applications of the benomyl/carbendazim rapid assay

    GENERAL COMMENTS: This procedure describes the preparation of thiabendazole (TBZ) standards used in applications of the Benomyl/Carbendazim RaPID Assay. Standard concentrations of 10, 50 and 250 ng/mL (ppb) TBZ and a control concentration of 100 ppb TBZ are prepared by making appropriate dilutions of a concentrated TBZ solution in the Benomyl/Carbendazim Sample Diluent. The standards and ...


  • Arsenic, antimony and chromium speciation using HPLC-ICP-MS in selected river ecosystems of Upper Silesia, Poland – a preliminary study and validation of methodology

    Upper Silesia is the most transformed by humans of the Polish territories. As a result of mining, urbanization and other industrial activities, irreversible changes have taken place in the environment. In this paper, the method of collecting, preserving, storing and preparing samples from four Silesian rivers was optimized. Silesian sediment and river water samples are a challenge for the ...


    By IWA Publishing

  • An overview of post-column derivatization methods from a pharmaceutical applications perspective

    High performance liquid chromatography (HPLC) is the technique of choice for separating analytes pursuant to their detection, identification, quantification and/or purification. Most organic substances, and certainly the majority of pharmaceuticals, are polar, nonvolatile or thermally labile molecules that are amenable to HPLC separation. Moreover, the availability of a large variety of LC column ...


    By Pickering Laboratories, Inc.

  • o-Phthalaldehyde Reagent

    Introduction Primary amines form highly fluorescent adducts when reacted with o-Phthalaldehyde (OPA) and a mercaptan under basic conditions. At a pH>9 and ambient temperature, reaction is generally complete within 30 seconds. The products of this reaction, 1-alkyl-2-alkylthio-substituted isoindoles, exhibit optimal excitation at 330 nm and maximal emission at 465 nm. The reagents ...


    By Pickering Laboratories, Inc.

  • Solid-state fermentation for production of gibberellic acid using agricultural residues

    Solid-State Fermentation (SSF) was employed using agricultural residues, viz. pigeon pea pod (Cajanus cajan), corncobs (Zea mays), sorghum straw (Sorghum vulgare) and pea pod (Pisum sativum) for the production of gibberellic acid (GA3) using Fusarium proliferatum NCIM1105. Studies revealed that these agricultural residues have supported excellent growth of the fungi in modified medium and gave ...


    By Inderscience Publishers

  • News on Air 2013, Volume 1: Products for Sampling

    For decades, Sigma-Aldrich has been a key supplier of innovative & high technology air monitoring products for various areas of gas/air sampling. Enclosed, you will find an overview on new and interesting devices to improve or simplify your air sampling. Supelco and Sigma-Aldrich offer a range of active and passive air sampling products, in addition to various analytical chemistry tools ...


    By Sigma-Aldrich Co., LLC

  • Analysis of biogenic amines food and physiological samples

    Histamine and other polyamines such as Putrescine, Cadaverine, Spermidine and Spermine are products of decomposition. The level of histamine, in particular, has been used as a regulatory guideline for degree of decomposition in fish. Also, Histamine and Tyramine levels are of interest to producers of wine and cheese. The polyamines, Spermidine, Spermine and Putrescine are elevated in neoplastic ...


    By Pickering Laboratories, Inc.

  • ChlorAC Buffer

    Introduction Trace analysis of carbamate insecticide residues in water is a routine requirement in the U.S. Since several of the common carbamates — Carbaryl, Oxamyl, Hydroxycarbofuran — are labile in water due to oxidation or hydrolysis, the samples and standards must be preserved in order to obtain valid results. USEPA Method 531.1 specifies pH adjustment, ...


    By Pickering Laboratories, Inc.

  • Designing PEDOT–based sensors for antioxidant analysis

    Antioxidants play important roles in food quality and the protection and promotion of human health. The most commonly used antioxidant determination techniques are the Folin–Ciocalteu assay and HPLC analyses. However, these methods have various disadvantages such as long time requirements, low sensitivity, interfering agents etc. Cyclic voltammetry at inert electrodes is another method for ...


    By Inderscience Publishers

  • Developing equipment specific lockout/tagout procedures – Case Study

    Challenge: Antea®Group was contracted by one of the world’s largest chemical manufacturing organizations to provide equipment-specific lockout / tagout procedures at their largest Research and Develop facility in North America. The overall objective of the project was to evaluate the worker risks during maintenance and repair operations associated with laboratory ...


    By Antea Group - USA

  • Rapid raw material identification for formulation compounds using handheld Raman technology

    Ever since the European Medicines Agency (EMA) recommended that all pharmaceutical companies test every raw material that passes through their manufacturing facilities, this practice has attracted great interest in the nutraceuticals, food manufacturing, cosmetics, and agricultural industries, pushing them to strive for more rigorous and technology-oriented quality control standards. In recent ...


    By B&W Tek

  • Manufacturers face challenges with pharmaceutical impurities

    Pharmaceutical manufacturers may face various challenges when attempting to meet the United States Pharmacopeia (USP) requirements for residual solvents (volatile organic chemicals).Residual solvents in pharmaceuticals are trace level impurities of volatile organic compounds in final products or excipients. In general, residual solvents originate from manufacturing processes related to the ...


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