A thin-layer chromatographic screening test for organophosphorus pesticide residues

Abstract

A procedure is proposed for use as a screening test for the presence of traces of organophosphorus pesticides in vegetable tissue. The compounds are extracted with dichloromethane and the extracts are cleaned-up on silicagel chromatoplates developed with hexane-acetone solution, 5 + 1. Eluted compounds are then oxidised with ammonium persulphate or a nitric acid-perchloric acid mixture for phosphorus determinations by molybdenum-blue procedures. Good recoveries are reported from a range of crop samples. Mobile solvents required for the clean-up of some polar pesticides and metabolites on multi-band chromatoplates are also listed.