Abstract
A novel chromogenic spray reagent "hydralazine" (phthalazin-1-yl-hydrazine) is reported for thin-layer chromatographic (TLC) detection and identification of synthetic pyrethroids cypermethrin, deltamethrin, and lambda-cyhalothrin from their dilute commercial formulations ranging from 2.5% to 25%. Alkaline hydralazine forms orange-yellow hydrazones with these insecticides at room temperature and does not require any further treatment. Reaction mechanism is discussed. The necessary TLC parameters like pH and concentration of analyte are also suggested for the efficient detection of these toxic pyrethroid insecticides.