Use of potassium iodate for thin-layer chromatographic detection of sulphur-containing organophosphorus insecticides

Abstract

The misuse of sulphur-containing organophosphorus insecticides results in many instances of poisoning. This paper describes a spray reagent for their detection in biological materials by thin-layer chromatography. Sulphur-containing organophosphorus insecticides react with acidified potassium iodate liberating free iodine, which in turn reacts with starch solution to give a blue colour. In alkaline media the colour is intensified and consequently the sensitivity of detection increases. There is no interference from other organochloro insecticides or even carbamate insecticides or from the constituents of visceral extracts (amino acids, peptides, proteins, etc). The limit of detection is ca. 1 µg.