Liquid-gel partitioning using Lipidex in the determination of polychlorinated biphenyls in cod liver oil

A technique was developed for transfer of fat and polychlorinated biphenyls from cod liver oil into the lipophilic gel Lipidex 5000. Subsequent elution of the gel separated about 60% of the fat from the sample. Following further purification on aluminium oxide and silica gel, toxic non-ortho- and mono-ortho-PCB congeners were isolated in two separate fractions on charcoal. Recoveries were studied by addition of twelve different PCB congeners to 0.2g of fat. The non-ortho-PCBs were labelled with ¹³C. The recoveries of 5–50 ng of the unlabelled compounds were 80–100% and those of 50–100 pg of the labelled compounds were 76–106%.