A new spray reagent for selective detection of dichlorvos by thin-layer chromatography

The misuse of dichlorvos (DDVP), an organophosphorus insecticide, results in many instances of poisoning. This paper describes a new spray reagent for selective detection of dichlorvos in biological materials by thin-layer chromatography. Dichlorvos in presence of moisture breaks down to dichloroacetaldehyde which in turn reacts with phenylhydrazine hydrochloride to give a yellowish red colour. In acidic media the colour is intensified and consequently the sensitivity of detection increases. 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 interfere. The limit of detection is ca 10 mug.