Improving analysis of pesticides

14 Dec 2006

Product news

Genevac have released a new application report that discusses a novel sample preparation protocol and evaluates a centrifugal evaporation system that together increase recovery of volatile compounds enabling improved analysis of pesticides.

During preparation of environmental samples, containing semi-volatile pesticides, evaporation becomes a critical step because of the need to avoid compound loss during the concentration process. Analyte loss is detrimental to accurate analysis, and official directives must be satisfied with regard to minimum analyte recovery.

The report, compiled by the Environmental Protection Agency of Tuscany, Italy (ARPAT), evaluates a new evaporator (the Genevac EZ2-ENVI) to determine the optimal concentration process and then describes tests carried out on real matrices spiked with pesticides to validate the new sample preparation protocol. The new processes and methods were then compared to the original method used by the ARPAT laboratories.

The report concludes that the new sample preparation protocol using the EZ2-ENVI evaporator delivers satisfactory recovery and reproducibility for the analysis of volatile pesticide compounds extracted from organic matrices. In addition reducing the number of sample transfers between different containers, and eliminating the filtration step by addition of anhydrous sodium sulphate directly to the samples significantly improve the sample preparation protocol. The evaporators' ability to provide hands-free automated concentration of a number of samples at the same time and to provide protection from cross contamination and bumping was noted to deliver significant productivity benefits compared to using a rotary evaporator.

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Sample PreparationSample preparation can improve the quality and speed of separation techniques. Products to assist sample preparation include filtration equipment, evaporators, membranes and sieves.CentrifugesCentrifuges are used to separate particulates suspended in a liquid via the application of a centrifugal force including cells, macromolecules, nanoparticles and precipitates. Centrifuges come in three sizes: microcentrifuges, benchtop and floor-standing centrifuges, depending on the volume and number of samples that require separation. When choosing a centrifuge, consider its maximum separation power indicated by its relative centrifugal force (RCF) value. Low force centrifuges reach a maximum RCF of 8,000 g, high-force centrifuges can reach maximum RCF values of 80,000 g. For extremely high forces, consider ultracentrifuges (up to 800,000 g). Refrigerated and vacuum centrifuges also known as concentrators are available for more specialized applications. A range of volumes are available for centrifuge tubes and microfuge tubes, depending on sample sizes. Find the best centrifuges in our peer-reviewed product directory: compare products, check customer reviews and receive pricing direct from manufacturers.Environmental Monitoring and TestingEnvironmental monitoring and testing uses handheld portable analyzers, kits, spectrometers or chromatography systems for air, water, soil, food and other sample testing. Useful features of analyzers such as BOD and COD include portability, easy calibration, automation and sensitivity.  Environmental test kits for pH, water, moisture, etc, should be accurate, sensitive, reliable, fast and easy to use.Evaporators and Freeze DryersCentrifugal evaporation is used for solvent removal from a sample. This is a useful technique for sample concentration or sample drying. Many centrifugal evaporators are modular with a central vacuum pump for generating low pressure. Useful features of evaporators or vacuum ovens include minimal solvent bumping, solvent resistance, computer control, temperature regulation and benchtop design.