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hplc sampling Applications

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    Improved Reproducibility and Reduced Sample Preparation Time for the HPLC Analysis of Aflatoxins in Raw Peanut Paste

    The US FDA and international regulatory agencies have set contamination levels for aflatoxins in animal feedstuffs. Since Aspergillus may infect commodities pre-harvest, during storage or during processing, monitoring for aflatoxins in associated agricultural commodities at all stages of production is requisite. Field screening methods exist that are adequate to estimate contamination levels for aflatoxins. When additional confirmation or quantification is desired, chromatographic laboratory analysis is often necessary. Preparation of matrix samples prior to chromatographic analysis typically requires extraction and purification. Commonly, immunoaffinity columns (IAC), which employ a multi-step bind and elute mechanism to concentrate and purify aflatoxins, are used to purify matrix samples for subsequent analysis. Solid phase extraction (SPE), an alternate method which may use interference removal, can also be employed.

    By Sigma-Aldrich Co., LLC based in Bellefonte, PENNSYLVANIA (USA).

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    Analysis of Herbicides in Drinking Water

    Herbicides are used throughout the world to combat the growth of unwanted plant life. These polar compounds are hydrophilic, so they may find their way into drinking water sources. While gas chromatography has historically been the preferred technique for analysis of herbicides in water samples, the use of LC-MS/MS for this application is gaining acceptance. This is due to the power of MS/MS to provide detailed identification of multiple analytes, but also in part due to the variety of HPLC stationary phases that are available. In particular, several HPLC phases are available that provide great retention and peak shapes for polar analytes, such as herbicides, even under mostly aqueous mobile phase conditions. The combination of these factors may possibly eliminate need for time-consuming sample preparation.

    By Sigma-Aldrich Co., LLC based in Bellefonte, PENNSYLVANIA (USA).

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    Determination of Additives in Beverages using Ascentis Express Columns

    Beverages, such as sodas and energy drinks, can include a number of polar ingredients, which are easily soluble in the water matrix of the drinks. These ingredients include sweeteners (sugars and sugar substitutes), caffeine, vitamin supplements, amino acids, organic acids, and plant extracts. Because the analytes are already in solution, there is no need for extensive sample preparation. Dilution followed by direct injection into an HPLC is typically suitable. In this article we present two beverage applications using Ascentis Express HPLC columns. Ascentis Express columns offer faster HPLC on any system. One benefit is their ability to produce the resolution, efficiency, and speed on conventional HPLC systems that is associated with the use of sub-2 micron columns on a UHPLC system, without generating high backpressure. Column chemistries (RP-Amide and HILIC) were selected for this article based on their enhanced performance with polar compounds in comparison to C18.

    By Sigma-Aldrich Co., LLC based in Bellefonte, PENNSYLVANIA (USA).

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