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Determination of Pesticides in Composite Dietary Samples By Gas Chromatography/Mass Spectrometry in the Selected Ion Monitoring Mode Using a Temperature Programmable Large Volume Injector With Pre-Separation Column

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Abstract:Use of a temperature-programmable pre-separation column in the gas chromatographic injection port permits determination of a wide range of semi-volatile pesticides including organochlorines, organophosphates, triazines, and anilines in fatty composite dietary samples while reducing sample preparation time and solvent consumption. Dietary samples are mixed with diatomaceous earth and Soxhlet extracted with an azeotropic solution of hexane and acetone. Sample preparation uses liquid-liquid partitioning over diatomaceous earth followed by normal phase chromatography over partially deactivated alumina. The final clean-up step occurs in a pre-separation column in the GC injector, which is able to perform splitless transfer of the analytes to the analytical column and purge 99% of the high molecular weight residue. Detection is performed by gas chromatography/mass spectrometry in the selected ion monitoring mode. Method detection limits are at or below 2 ng/g for 24 of 35 pesticides studied, with recovery between 70 and 125% for 27 pesticides in samples fortified at 10 ng/g. Recovery was not dependent on fat content when measured in laboratory fortified samples containing 1%, 5%, and 10% fat by weight. Precision over multiple injections was acceptable with a relative standard deviation of 2.6-15% for 25 analytes.
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Citation:Rosenblum, L., T. Hieber, and J. N. Morgan. Determination of Pesticides in Composite Dietary Samples By Gas Chromatography/Mass Spectrometry in the Selected Ion Monitoring Mode Using a Temperature Programmable Large Volume Injector With Pre-Separation Column. JOURNAL OF AOAC INTERNATIONAL 84(3):891-900, (2001).
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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: Journal
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Published: 06/01/2001
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Related Entries:
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Bullet Item Xenobiotic Methods Development for Human Exposure Assessment Research
spacer Relationship Reason:   A Project of the Product
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Last Updated on Monday, October 22, 2007
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