Detection and separation of fenpropathrin, flucythrinate, fluvalinate, and PP 321 by thin-layer chromatography

Four synthetic pyrethroids having alpha-cyano ester groups, i.e., fenpropathrin, flucythrinate, fluvalinate, and PP 321, are separated by thin-layer chromatography and detected by a new set of chromogenic reagents. Synthetic pyrethroids containing the alpha-cyano group react with sodium hydroxide to liberate cyanide which forms pink spots with o-dinitrobenzene and p-nitrobenzaldehyde. The detection limit is 0.1 microgram and the method can be applied for identification and confirmation of these synthetic pyrethroids in vegetables.