ENANTIOMER SELECTIVE SEPARATION OF TOXAPHENE CONGENERS ISOLATED FROM SEAL BLUBBER AND OBTAINED BY SYNTHESIS

Stationary phases based on dimethyl-t-butylsilylated heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin diluted with different polysiloxanes were developed for the enantiomer separation of chiral toxaphene congeners by high resolution gas chromatography (HRGC). They allowed to determine the enantiomer ratio of an octa- and nonachloro congener isolated from seal blubber. The found ratios of 1,024 and 1,059 were very close to those of the racemates and indicate that enantiomer selective metabolisation is not significant in seals. Furthermore, the enantiomer separation of 11 racemic toxaphene congeners obtained by synthesis was also performed. Two of them had the same retention times as the isolated congeners on 3 or 5 stationary phases, respectively, and similar negative ion chemical ionisation mass spectra. First attempts are made to explain differences in the observed enantiomer separations by the steric structure of the congeners. In addition, general aspects and difficulties of enantiomer selective separations by HRGC are discussed.