Enantioselective determination of chiral 2,2',3,3',4,6'-hexachlorobiphenyl (PCB 132) in human milk samples by multidimensional gas chromatography/electron capture detection and by mass spectrometry.

The enantiomeric ratio (ER) of the chiral polychlorinated biphenyl (PCB) 132 (2,2',3,3',4,6'-hexachlorobiphenyl) was determined in human milk samples. The enantiomers were separated by multidimensional gas chromatography (MDGC), using different achiral columns for pre-separation and a Chirasil-Dex column for enantiomer separation, and quantified by electron-capture detection (ECD) and by mass spectrometry (MS/SIM). The determined enantiomeric ratios varied between 0.45-0.85 (enantiomeric excess: 38-8%).

Enantioselective degradation of alpha-hexachlorocyclohexane and cyclodiene insecticides in roe-deer liver samples from different regions of Germany.

Remarkably high concentrations of alpha-hexachlorocyclohexane (alpha-HCH), cis-heptachlorepoxide and oxychlordane were found in roe-deer liver samples both from the northern and southern German states Schleswig-Holstein and Baden-Württemberg, respectively. The data revealed no significant regional differences, but they showed some common characteristics: a preferential degradation of (+)-alpha-HCH, and a preferential enrichment of (+)-oxychlordane and of (+)-cis-heptachlorepoxide as determined by chiral capillary gas chromatography using modified cyclodextrin phases. Calculation of the spearman rank correlation coefficients rS supported the assumption that higher concentrations of alpha-HCH may result in a stronger decomposition of the (+)-enantiomer, while higher levels of cis-heptachlorepoxide and oxychlordane appear to lead to a faster decomposition of the respective (-)-enantiomer or a preferential formation of the respective (+)-enantiomer.