Organophosphorus sulphides, sulphoxides and sulphones. Part I. Determination of residues in fruit and vegetables by gas-liquid chromatography

Abstract

Conditions have been established for the routine quantitative determination of residues of demephion, demeton-S-methyl, disulfoton, fenamiphos, fensulfothion, fenthion, phorate, terbufos, thiometon and their toxic metabolites following conversion into the sulphones. Packed column gas chromatography-mass spectrometry demonstrated that most of the sulphoxides tended to decompose under the conditions required for gas chromatography, whereas most of the sulphides and sulphones were unaffected by such conditions. Temephos and its metabolites and the metabolites of vamidothion decomposed completely during gas chromatography. Some suggestions are given for assessing and avoiding the column priming and enhancement problems often observed in the gas chromatography of these and other polar organophosphorus pesticides.