Thin-layer chromatographic detection of phosphorothionate and phosphorothiolothionate pesticides using 4-amino-N,N-diethylaniline.

A thin-layer chromatographic method using a novel chromogenic reagent was developed to detect the phosphorothionate and phosphorothiolothionate groups of pesticides. On reaction with 4-amino-N,N-diethylaniline and subsequent exposure to bromine vapour, these compounds yield a deep magenta product. The chromogenic reagent is specific to these organophosphates and gives no response to phosphorothiolates and substituted phosphonates. The method is rapid and highly sensitive. The limit of detection is 0.05-0.5