title: Chromatographic enrichment and enantiomer separation of axially chiral polybrominated biphenyls in a technical mixture.
abstract: The separation properties of different chromatographic methods regarding the enantioselective separation of axially chiral (atropisomeric) polybrominated biphenyls (PBB) were studied. For this purpose, the technical hexabromobiphenyl product Firemaster BP-6 was characterised by gas-chromatography coupled to electron capture detection (GC/ECD) and electron-capture negative ion mass spectrometry (GC/ECNI-MS) as well as by liquid chromatographic fractionating on active carbon and celite. Twelve individual PBBs including potential atropisomeric PBBs were isolated from Firemaster BP-6 by reversed-phase high-performance liquid chromatography (HPLC) on three serially coupled octadecylsilane columns. Six of the 12 isolated PBBs (three tri-ortho and di-ortho substituted PBBs, respectively) were separated into atropisomers on a HPLC column containing permethylated beta-cyclodextrin on silica. Moreover, the temperature dependency of the enantiomer separations is discussed. Gas chromatographic enantiomer separation of PBBs is a very demanding task due to high elution temperatures. However, the atropisomers of one tri-ortho substituted PBB congener (PBB 149) could be resolved on a column coated with randomly modified heptakis(6-O-tert.-butyldimethylsilyl-2,3-di-O-methyl)-beta-cyclodextrin in OV 1701.
authors.affiliation: Norwegian Institute for Air Research (NILU), The Polar Environmental Centre, Tromsø. urs.berger@nilu.no
authors.forename: Urs
authors.initials: U
authors.lastname: Berger
authors.forename: Walter
authors.initials: W
authors.lastname: Vetter
authors.forename: Arntraut
authors.initials: A
authors.lastname: Götsch
authors.forename: Roland
authors.initials: R
authors.lastname: Kallenborn
mesh_terms: D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D011075:Polybrominated Biphenyls / Q000737:chemistry / Q000302:isolation & purification*; D013237:Stereoisomerism
chemical_list: D011075:Polybrominated Biphenyls