title: Enantioselective gas chromatography/mass spectrometry of methylsulfonyl PCBs with application to arctic marine mammals.
abstract: Four different commercially available cyclodextrin (CD) capillary gas chromatography (GC) columns were tested for the enantioselective separation of nine environmentally persistent atropisomeric 3- and 4-methylsulfonyl PCBs (MeSO2-CBs). The selected columns contained cyclodextrins with various cavity diameters (beta- or gamma-CD), which were methylated and/or tert-butyldimethylsilylated (TBDMS) in the 2,3,6-O-positions. The beta-CD column with TBDMS substituents in all of the 2,3,6-O-positions was by far the most selective column for the MeSO2-CBs tested. Enantiomers of congeners with 3-MeSO2 substitution were more easily separated than those with 4-MeSO2 substitution. The separation also seemed to be enhanced for congeners with the chlorine atoms on the non-MeSO2-containing ring and clustered on one side of the same ring. The 2,3-di-O-methyl-6-O-TBDMS-beta-CD was found to give somewhat better selectivity than the corresponding gamma-CD, in comparison between the two columns, which were identical in all other respects. Enantioselective analysis of arctic ringed seal (Phoca hispida) and polar bear (Ursus maritimus) adipose tissue revealed a strong dominance of certain enantiomers. For example, the enantiomer ratio (ER) of 3-MeSO2-CB149 was 0.32 and < 0.1 in ringed seal blubber and polar bear fat, respectively. These low ER values are indicative of highly enantioselective formation, enantioselective metabolism, enantioselective transport across cell membranes, or a combination of the three in both species. Comparable results for the enantiomeric analysis of MeSO2-CBs in biotic tissue extracts were obtained using two highly selective mass spectrometric techniques, ion trap mass spectrometry/mass spectrometry and electron capture negative ion low-resolution mass spectrometry.
authors.affiliation: Institute of Environmental Chemistry, Umeå University, Sweden. kwg@chem.umu.se
authors.forename: K
authors.initials: K
authors.lastname: Wiberg
authors.forename: R
authors.initials: R
authors.lastname: Letcher
authors.forename: C
authors.initials: C
authors.lastname: Sandau
authors.forename: J
authors.initials: J
authors.lastname: Duffe
authors.forename: R
authors.initials: R
authors.lastname: Norstrom
authors.forename: P
authors.initials: P
authors.lastname: Haglund
authors.forename: T
authors.initials: T
authors.lastname: Bidleman
mesh_terms: D000818:Animals; D001110:Arctic Regions; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D046048:Seals, Earless / Q000378:metabolism*; D013237:Stereoisomerism; D001503:Ursidae / Q000378:metabolism*
chemical_list: D011078:Polychlorinated Biphenyls