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Comparison of Gc-Fpd and Gc/Aed for Determination of Organophosphate Pesticides in Composite Diet Samples

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Abstract:In order to assess an individual's total exposure to contaminants in the environment, it is essential that the contribution of dietary exposure be quantified. As a result, USEPA's National Exposure Research Laboratory has initiated a program to develop methods to measure chemical pollutants in dietary samples collected from individuals. Methods developed previously utilizing GC/MS-SIM for pesticides in composite diets are unsuitable for many organophosphorus pesticides. Consequently the present study was undertaken to evaluate the suitability of GC/FPD and GC/AED for determination of organophosphorus pesticides in composite diets. Composite diet samples containing three levels of fat (1, 5 and 10%) and fortified with 37 organophosphorus pesticides were extracted with a methylene chloride-acetone solvent mixture using accelerated solvent extraction and cleaned up using diatomaceous earth and C18 reversed phase chromatography. Pesticides were quantitated by capillary GC using a DB-17 column with both flame photometric detection (phosphorous mode) and atomic emission detection. Recovery of fortified pesticides, precision (% relative standard deviation) and method detection limits were determined using both GC/FPD and GC/AED. Recoveries ranged from 30-93% for 37 pesticides studied. Recoveries from high fat composite diets were greater than 70% for 30 of 37 pesticides. RSDs were generally below 15%. Recoveries were poor for naled, methamidophos, acephate, chlorethoxyfos, dichlorvos, and disulfoton. In general GC/FPD was more snesitive than GC/AED for most analytes tested. Specific results will be presented along with a discussion of advantages and disadvantages of each technique.
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Citation:Morgan, J. N., and P. Kauffman. Comparison of Gc-Fpd and Gc/Aed for Determination of Organophosphate Pesticides in Composite Diet Samples. Presented at Eastern Analytical Symposium, Atlantic City, NJ, October 29-November 3, 2000.
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Contact: Mary P. O'Bryant - (919)-541-4871 or obriant.mary@epa.gov
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Division: Microbiological & Chemical Exposure Assessment Division
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Branch: Chemical Exposure Research Branch
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Product Type: Abstrct/Oral
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Presented: 10/29/2000
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Related Entries:
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Bullet Item Dietary Exposure Methods and Models
spacer Relationship Reason:   A Project of the Product
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Last Updated on Monday, October 22, 2007
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