A NEW SPRAY REAGENT FOR SELECTIVE DETECTION OF DICHLORVOS BY THIN-LAYER CHROMATOGRAPHY

The misuse of dichlorvos (DDVP), an organophosphorus insecticide, resu lts in many instances of poisoning. This paper describes a new spray r eagent for selective detection of dichlorvos in biological materials b y thin-layer chromatography. Dichlorvos in presence of moisture breaks down to dichloroacetaldehyde which in turn reacts with phenylhydrazin e hydrochloride to give a yellowish red colour. In acidic media the co lour is intensified and consequently the sensitivity of detection incr eases. The reagent is selective for dichlorvos, other organophosphorus insecticides failed to give a coloured spot. Moreover organochlorine, carbamate and synthetic pyrethroid insecticides or even constituents of visceral extracts (amino acids, peptides, proteins etc.) do not int erfere. The limit of detection is ca 10 mug.