A New Chromogenic Spray Reagent for Detection and Identification of Monocrotophos

A new chromogenic spray reagent is described for chromatographic detection and identification of monocrotophos, an organophospho-rus insecticide by HPTLC. Monocrotophos on alkaline hydrolysis yields one molecule each of O,O-dimethylphosphoric acid and N-methylacetoacetamide. After acidification, N-methylacetoacetamide gives the enol form of monomethylamide which reacts with ferric ions to yield a purple complex. Other organophosphorus, orga-nochlorine, pyrethroid, and carbamate insecticides and constituents of viscera (amino acids, proteins, peptides, etc.) do not react with this reagent. The detection limit for monocrotophos is ca 0.5 μg.