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DETERMINATION OF PYRETHROID PESTICIDES IN COMPOSITE DIETARY SAMPLES
MORGAN, J. N., P. KAUFFMAN, T. E. HIEBER, AND J. BRISBIN. DETERMINATION OF PYRETHROID PESTICIDES IN COMPOSITE DIETARY SAMPLES. Presented at European Pesticide Residue Workshop, Corfu, GREECE, May 21 - 25, 2006.
The overall goal of this research program is to identify those chemicals, pathways, and activities that represent the highest potential exposures to children and to determine the factors that influence these exposures. The following objectives will address this goal:
Revise and refine the existing research plan for children's exposure measurements research.
Collect measurement data on children's exposures.
Provide analytical support to children's pesticide exposure research.
Develop analytical methods for pesticides in duplicate diet food samples.
Develop and apply analytical methods for other chemicals including but not limited to brominated diphenyl ethers, phthalates, perfluorinated chemicals.
Evaluate the impact of chiral chemistry on the risk to children and exposure assessment.
Provide support to the National Children's Study.
Perform data analyses to fill critical data gaps.
Conduct analyses of dietary samples and refine the dietary model for the dietary exposure algorithm.
The U.S. Environmental Protection Agency's National Exposure Research Laboratory (NERL) conducts aggregate exposure studies for determining an individual's exposure to a broad range of target analytes in composite dietary samples. The objective of this work is to develop an analytical method, with sub-part per billion (ppb) detection limits, for the determination of pyrethroid pesticides in composite dietary samples collected in exposure studies.
Pressurized solvent extraction (hexane, acetonitrile, and hexane/acetone) and clean-up with solid phase sorbents (diatomaceous earth, alumina, graphitized carbon black and primary secondary amine) were evaluated for both lyophilized and wet composite food samples. Detection techniques included gas chromatography/mass spectrometry in the selected ion monitoring mode and gas chromatography/tandem mass spectrometry. Target performance criteria were 60-140% recovery, 30% relative standard deviation, and sub-ppb detection limits. Results suggest that recoveries in this range are generally achievable, while sub-ppb detection limits may present a significant challenge. A comparison of method performance parameters, including recovery, precision and detection limits, using a variety of extraction parameters, clean-up procedures, and detection techniques, will be presented.