ISOLATION AND DETERMINATION OF METHYLSULFONYL-PCBS IN BIOLOGICAL SAMPLES BY SULFURIC-ACID PARTITIONING, ADSORPTION CHROMATOGRAPHY AND GC-ECD

Methylsulfonyl (MeSO2) metabolites of polychlorobiphenyl (PCBs) have been shown to be present in humans, in tissues of animals fed with PCBs and in relatively high levels in free living animals such as otter and seals. In addition, serious effects of these compounds have been reported in mice. It is therefore necessary to develop analytical methods for the determination of MeSO2-PCBs, which can be applied for monitoring purposes. In this contribution the incorporation of the determination of MeSO2-PCBs in an existing multiresidue method for the determination of chlorinated and brominated pollutants is reported. Aromatic MeSO2 compounds dissolve in sulphuric acid. In the multiresidue method, sample extracts are initially cleaned up with sulphuric acid. The resulting acid layer, which is usually discarded, contains the MeSO2 compounds, which are isolated by additional liquid liquid extraction and adsorption chromatography using aluminiumoxide and silica. Recoveries of this procedure for 6 MeSO2-PCBs and MeSO2-DDE are in the 75-100% range. The method was applied to Grey seal and otter tissue and White-tailed eagle eggs. Results show intra- and interspecies differences in the patterns of MeSO2 compounds. It is estimated that levels of MeSO2-PCBs can amount to between 2 and 10 % of the total PCB levels present in mammals.