A spray reagent for the detection of pyrethroid insecticides containing a nitrile group by thin-layer chromatography is described. These insecticides on alkaline hydrolysis yield cyanide ion, which in turn reacts with copper(II) acetate and o-tolidine in an acetic acid medium to give a blue colour. Organochlorine, organophosphorus and carbamate insecticides do not interfere. The limit of detection is about 1 microgram.

No abstract

Zinc chlorlde-diphenylamlne reagent, whose use has been reported for the detection of organochlorine insecticides by thin layer chromatography, was further studied for its ability to detect the organophosphorus insecticides phorate, phosphamldon, DDVP, and phosalone and the carbamate Insecticides carbaryl and aldicarb. These Insecticides give Intense blue-green spots with this reagent. The procedure can be applied to the detection of the insecticides in biological materials and thus has a potential use in forensic toxicology