GEL-PERMEATION AND FLORISIL CHROMATOGRAPHIC CLEANUP AND GAS-CHROMATOGRAPHIC DETERMINATION OF ORGANOCHLORINE PESTICIDES IN EGGS

Cleanup of residual organochlorine pesticides (OCPs; alpha-, beta-, ga mma-, and delta-BHC; aldrin; dieldrin; p,p'-DDE; o,p'-DDT; p,p'-DDD; a nd p,p'-DDT) in eggs by gel permeation chromatography (GPC) and Floris il minicolumn chromatography is described. Ten OCPs in purified extrac t are determined by gas chromatography with electron capture detection . The lipids extracted from whole egg are cleaned up first by GPC with an Envirogel column and an ethyl acetate-cychlohexane (1 + 1,v/v) mob ile phase and then by Florisil minicolumn chromatography with 15% (v/v ) diethyl ether-hexane eluant. Cleanup is highly efficient. Average re coveries of 10 spiked OCPs (0.0025-0.0125 ppm) ranged from 81 to 101%, with coefficients of variation between 1 and 14%. The detection limit was 0.001 ppm for the 10 OCPs.