title: Sorbent-assisted liquid-liquid extraction (Chem-Elut) of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans in the lipid fraction of human blood plasma.
abstract: This work compares two lipid extraction methods for determining 24 polychlorinated biphenyls (PCBs), seven dibenzo-p-dioxins (PCDDs) and ten dibenzofurans (PCDFs) in human blood plasma. The first method was based on conventional liquid-liquid partitioning with chloroform-methanol and the other made use of a sorbent (Chem-Elut) to facilitate the partitioning of lipids into a mixture of hexane and 2-propanol. A multi-layer-silica column including acid- and base-impregnated silica gel was used to reduce the amounts of lipid present in the samples before a basic alumina clean-up step and activated carbon fractionation of planar analytes (PCDD/Fs and non-ortho-PCBs) and non-planar analytes (including ortho-chlorinated PCBs). Gas chromatography coupled to high resolution mass spectrometry was used to identify and quantify the analytes in the two fractions. The wet weight based concentrations obtained by the two methods were in agreement but both methods suffer from large organic solvent consumption. The toxic equivalencies derived for PCBs and PCDD/Fs using the two methods were also in agreement. However, the chloroform-methanol method gave slightly higher lipid recoveries, although with greater variation, than the sorbent-assisted method. Nevertheless, despite giving lower lipid recoveries, the sorbent-assisted method has advantages in ease of use and applicability to whole blood samples. The formation of emulsions was avoided with the Chem-Elut method, which probably explains the lower variability in the lipid determinations.
authors.affiliation: Department of NBC Defence, Swedish Defence Research Agency, FOI, SE-901 82 Umeå, Sweden. hakan.wingfors@foi.se
authors.forename: H
authors.initials: H
authors.lastname: Wingfors
authors.forename: M
authors.initials: M
authors.lastname: Hansson
authors.forename: O
authors.initials: O
authors.lastname: Päpke
authors.forename: S
authors.initials: S
authors.lastname: Bergek
authors.forename: C-A
authors.initials: CA
authors.lastname: Nilsson
authors.forename: P
authors.initials: P
authors.lastname: Haglund
mesh_terms: D000327:Adsorption; D001572:Benzofurans / Q000097:blood*; D002623:Chemistry Techniques, Analytical / Q000379:methods; D000072338:Dibenzofurans, Polychlorinated; D004785:Environmental Pollutants / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D011078:Polychlorinated Biphenyls / Q000097:blood*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000097:blood*; D015203:Reproducibility of Results; D012989:Soil Pollutants / Q000097:blood*; D012997:Solvents
chemical_list: D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; D012989:Soil Pollutants; D012997:Solvents; D011078:Polychlorinated Biphenyls