An integrated analytical method for determination of polychlorinated aryl methyl sulfone metabolites and polychlorinated hydrocarbon contaminants in biological matrices

A simple column chromatography method was developed for separation and cleanup in the determination of chlorinated hydrocarbon contaminants and their methyl sulfone (MeSO2-) metabolites in biological tissues. The method was validated for determination of 11 polychlorinated biphenyls (PCBs), 15 tetra- to heptachloro 3- and 4-MeSO2-PCBs, 3-MeSO2-DDE, and tris(4-chlorophenyl)-methanol spiked to herring gull egg, smelt, and polar bear liver and adipose tissue using gas chromatography with electron-capture detection (GC-ECD). The overall mean recovery relative to the internal standard was 103% +/- 8%, independent of analyte, substrate type, and lipid extract weights up to approximately 0.7 g. Precision of replicate analyses of individual congeners was good. There were no significant residual biogenic or xenobiotic interferences in the aryl methyl sulfone fraction of any substrate. Sensitivity and linearity of molar response of MeSO2-PCBs and MeSO2-DDE was tested for ECD and electron-capture negative ion mass spectrometry monitoring the total ion current (TIC) and the molecular ion (SIM). The mean practical quantitation limit among MeSO2-PCBs and 3-MeSO2-DDE was lowest for SIM (2.1 +/- 0.9 pg) and similar for ECD and TIC (24.2 +/- 4.6 and 44.4 +/- 17.1 pg, respectively). Response factors were linear above the practical quantitation limit to at least the nanogram level for all three techniques. In spite of superior sensitivity, there was more inherent variability in the response factors for SIM (approximately 18%-56% CV) than for ECD (approximately 7%-12% CV) or TIC (approximately 11%-18% CV); therefore, ECD or TIC is recommended for quantitative analysis.