Determination of (+/-) elution orders of chiral organochlorines by liquid chromatography with a chiral detector and by enantioselective gas chromatography

Enantioselective gas chromatography (GC) with 5 modified cyclodextrins was applied to chiral organochlorines. A prerequisite for determining GC elutio n orders of enantiomers is the availability of enantioenriched standard sol utions. In addition to compounds reported before (e.g., alpha-HCH, PCB 174, oxychlordane), we determined the sign of optical rotation of enantioenrich ed solutions of e-aeee-pentachlorocyclohexene-1 (beta-PCCH), perdeuterated alpha-HCH (alpha-PDHCH), perdeuterated beta-PCCH, and the persistent compou nd of technical toxaphene-2-exo,3-endo,5-exo,9,9,10,10-heptachlorobornane ( B7-1453)-by liquid chromatography (LC) with a chiral detector. An enantioen riched solution of beta-PCCH was obtained by enantioselective degradation o f alpha-HCH with (-)-brucine, In addition to forming an enantiomeric excess of (-)-alpha-HCH, we formed enantioenriched (+)-beta-PCCH. In a similar st udy alpha-PDHCH showed the same behavior with respect to enantioselectivity . Dextrorotation of an enantioenriched solution of B7-1453 was also confirm ed by LC with a chiral detector. Enantioseparation of chiral organochlorine s on 5 chiral stationary phases resulted in several reversed elution orders . These results indicate that a careful check of elution orders of organoch lorine enantiomers is necessary prior to comparison of literature data for the study of enantioselective processes in the environment.