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DETERMINATION OF ORGANOPHOSPHATE PESTICIDES IN COMPOSITE DIET SAMPLES
Citation:
Kauffman, P AND J N. Morgan. DETERMINATION OF ORGANOPHOSPHATE PESTICIDES IN COMPOSITE DIET SAMPLES. Presented at AOAC International Meeting, Houston, TX, September 26-30, 1999.
Description:
USEPA's National Exposure Research Laboratory conducts research to measure the exposure of individuals to chemical pollutants through the diet, as well as other media. In support of this research, methods are being evaluated for determination of pollutants, including organophosphate pesticides, in composite diet samples. Existing methods for pesticides generally have been developed for regulatory purposes and often do not have sufficiently low detection limits for exposure studies. Consequently, there is a need to improve the performance of these analytical methods for the determination of pesticides in composite diet samples. Diatomaceous earth and C18 rewversed phase chromatography have been utilized by researchers at the U.S. FDA as a media for the cleanup of five organophosphate pesticides in solutions of edible vegetable oils. The current study evaluated this cleanup technique as applied to high fat (10%) and low fat (1%) composite diet samples, fortified with thirty-seven organophosphate pesticides. Samples were extracted with a methylene chloride-acetone solvent mixture using accelerated solvent extraction and cleaned up using the aforementioned media. Pesticides were quantitated by capillary GLC using a DB-17 column with flame photometric detection (phosphorous mode). Results of this study demonstrated that the procedure separated the pesticides from greater than 95% of the lipid material. The fortified pesticide recoveries range from 30 to 87%.