ENANTIOSELECTIVE DETERMINATION OF VARIOUS CHLORDANE COMPONENTS AND METABOLITES USING HIGH-RESOLUTION GAS-CHROMATOGRAPHY WITH A BETA-CYCLODEXTRIN DERIVATIVE AS CHIRAL SELECTOR AND ELECTRON-CAPTURE NEGATIVE-ION MASS-SPECTROMETRY DETECTION

Enantioenriched fractions of various chiral chlordane compounds (hepta chlor, cis-chlordane, trans-chlordane) and metabolites (cis- and trans -heptachlorepoxide, oxychlordane) were used to evaluate a high-resolut ion gas chromatography (HRGC) column with heptakis-[2,3-dimethyld-6-t- butyldimethyl silyl]-beta-cyclodextrin (TBDM) as chiral selector and e nantiomer elution sequences were determined. The enantioenriched fract ions were previously isolated from the racemates by enantioselective h igh-performance liquid chromatography (HPLC) using a permethylated bet a-cyclodextrin. Additionally, two octachlordanes, U82 and MC5, were is olated as racemates from technical chlordane using HRGC and then used for reference purposes. The TBDM column enantiomerically resolved cis- and trans-chlordane, MC5, cis- and trans-heptachlorepoxide, and oxych lordane; it did not enantiomerically resolve heptachlor, the octachlor dane U82 and the nonachlordane MC6. A 12-m column resulted in a better enantiomer resolution than a longer (23-m) column of the same type du e to a lower elution temperature. The TBDM column was used to analyze technical chlordane and chlordane residues in the fish oil reference m aterial SRM 1588, a cod liver oil. Isomer and enantiomer ratios of chl ordane residues in this reference material are reported and compared t o those reported in earlier studies on the same material and to data o n other fish species from the Baltic. (C) 1997 Elsevier Science Ltd.