Separation of pyrethroids by thin layer chromatography

A thin layer chromatographic method has been attempted for the detection of some synthetic pyrethroids (Cypermethrin and Fenvalerate) on a single plate using different solvent systems and chromogenic reagents. It is observed that heptanecyclohexane-ethyle acetate-water (60:40:15:15) can be used as a solvent system and 1% solution of vanillin in 80% sulphuric acid as a spraying reagent followed by heating of the plate at 125° C for 10 minutes for the separation of these compounds. This combination has been found to be the most suitable and reliable for the separation and identification of synthetic pyrethroids (cypermethrin and fenvalerate) analysed in this study. The spots developed were well separated and clear and they could be easily distinguished from each other in this solvent system.