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
125ml mixture of acetone: hexane (3:7 v/v). After
concentrating the eluate on rotary evaporator, final volume
was made to 2ml for analysis by gas liquid
chromatography (GC).