Development of spray reagent for TLC detection of pyrethroid insecticides using picric acid.

ABSTRACT

There have been a variety of approaches developed since the 1970s to detect pyrethroid pesticides based on gas chromatography (GC), thin layer chromatography (TLC), and high performance liquid chromatography (HPLC) with ultraviolet detection. A new thin layer chromatographic method was developed for the detection of common pyrethroids in forensic toxicology case exhibits. Various solvent systems were tried as mobile phase with different spray reagents; picric acid was used as specific spray reagent for deltamethrin, fenvalerate, and cypermethrin. The method developed is rapid and sensitive and can be used for routine case analysis with better separation. A new modified spray reagent was developed for the detection of synthetic pyrethroids containing a hydrolysable nitrile group such as deltamethrin, fenvalerate and cypermethrin using picric acid, that produces reddish-orange spots on a yellow background.