Abstract
The insecticides are broadly divided into organophosphates, organochlorines, carbamates, and pyrethroids. Various chromogenic spray reagents have been reported for the identification of these classes of pesticides and insecticides. Some of them are specific and some are general for a particular class of insecticides. The large volume of insecticides belong still to the organophosphates which can be divided into thio and non-thio insecticides, on the basis of the presence or absence of a sulfur atom. We here present alkaline sodium nitroprusside as a simple chromogenic spray reagent which reacts with only a specific type of organothiophosphorus insecticides and not all organothiophosphorus insecticides.