Analysis of organochlorine pesticides, polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans in human milk by extraction with the lipophilic gel Lipidex 5000.

A method for multicomponent determination of organochlorine contaminants in human milk is described. The lipophilic gel Lipidex 5000 was used for extraction of lipids and organochlorine compounds. Further purification and separation was achieved by chromatography on partly deactivated aluminium oxide, Lipidex, silica gel and active basic and acidic aluminium oxide. The concentrations of pesticides and polychlorinated biphenyls (PCBs) were determined by electron-capture gas chromatography. Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined by selected-ion monitoring capillary column gas chromatography-mass spectrometry at a resolution of 8000-9000. The levels of 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane, 1,1-bis(4-chlorophenyl)-2,2-dichloroethene, hexachlorobenzene, alpha-hexachlorocyclohexane, beta-hexachlorocyclohexane, dieldrin, trans-nonachlor, oxychlordane and PCBs found by this method agreed with the levels determined using a previous solvent-extraction method. Recovery experiments were performed by addition of pentachlorophenol and certain PCDDs and PCDFs. The average recovery of 0.5-2.0 ng pentachlorophenol per ml milk was 92%. Ten PCDDs and PCDFs reported to occur in milk were added at levels between 0.5 and 50 pg per ml milk. Recoveries of these compounds were on an average 79-91%.