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Analysis of O,S-dimethyl Hydrogen Phosphorothioate in Urine, a Specific Biomarker for Methamidophos

Analysis of O,S-dimethyl Hydrogen Phosphorothioate in Urine, a Specific Biomarker for Methamidophos

Elizabeth Tomaszewska, Vincent R Hebert

J Agric Food Chem. 2003 Oct 8;51(21):6103-9.

PMID: 14518930

Abstract:

A rugged and sensitive method was developed to monitor urinary concentrations of O,S-dimethyl hydrogen phosphorothioate (O,S-DMPT), a specific biomarker of exposure to the organophosphate insecticide methamidophos. After pH adjustment and C18 solid phase extraction column cleanup, the urine was lyophilized at a low temperature to prevent loss of possibly highly volatile and unstable O,S-DMPT metabolite. The dried residue was derivatized using N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide and 1% tert-butyldimethylchlorosilane (MTBSTFA + 1% TBDMCS) in acetonitrile. After it was filtered, the derivatized product was analyzed and quantified by gas chromatography using a pulse flame photometric detector specific for phosphorus compounds. The limit of detection for this method was 0.004 ppm with a limit of quantitation of 0.02 ppm of urine. The mean recovery value for O,S-DMPT from 17 urine samples fortified at varying concentrations was 108% with a standard deviation of 12%.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP77377527	N-tert-Butyldimethylsilyl-N-methyltrifluoroacetamide with 1% tert-Butyldimethylchlorosilane		77377-52-7	Price

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