Gas chromatographic determination of organochlorines in biota by preliminary fractionation on conditioned silica gel column

Abstract

A complete method is described for the reliable determination in animal tissues of polychlorinated biphenyls (PCBs), aldrin, p,p -DDE, heptachlor, o,p -DDT, p,p -DDT, p,p -DDD, CI. -BHC, Y -BHC (lindane), heptachlor epoxide, dieldrin and endrin. It aims at over coming a plethora of difficulties, the gravest of which deal with analytes loss and alteration, interference, identification, fouling of the column and the detector of the gas chromatograph, non-linear response of the latter and contamination. It comprises hexane extraction, removal oflipids on an alumina column, separation into six fractions on a silica gel column and injection into a gas chromatograph equipped with a 6.3Ni electron capture detector. Special attention is paid to the conditioning of the silica gel column and the identification of all the peaks, including those of th e PCBs.