For OC and SP insecticides, clean-up was carried out by using column chromatography. Column C60cm 22mm) was packed with Florisi l and activated charcoal(5:1 w/w) in between the two layers of anhydrous sodium sulphate. Extract was eluted with 125mi mixture of ethyl acetate: hexane(3 v/v). Eluate was concentrated to 2ml for residue analysis. Residues of OP and carbamates were also cleaned by adopting column chromatographic technique Column was packed with silica gel and activated charcoal(5: 1 w/w) in between the layers of anhydrous sodium sulphate. Extract was eluted with 125 mi mixture of acetone: hexane(3:7 v/v). After concentrating the eluate on rotary evaporator, final volume was made to 2m for analysis by gas liquid chromatography(GC).