Novel method for estimation of chlorinated pesticide residues in milk

A new, simple, and rapid procedure for determining chlorinated pesticide residues in milk is described. The entire acetonitrile extract from milk is passed through a 0.5 g activated charcoal chromatographic column. Chlorinated pesticides adsorbed on the charcoal are eluted with 100 mL acetone-hexane (1 + 1). The eluate is washed with water and 1% sodium carbonate solution, and chlorinated pesticides are extracted with hexane. The extract is concentrated and measured by electron capture gas chromatography. Recoveries from 50 mL milk samples fortified with 0.04-1.6 micrograms of different BHC isomers, 0.05-2 micrograms DDT and its metabolites, and 0.05-0.5 micrograms dieldrin ranged from 86.9 to 103.2%.