DETERMINATION OF COPLANAR POLYCHLORINATED BIPHENYL (CB) CONGENERS IN SEAL TISSUES BY CHROMATOGRAPHY ON ACTIVE-CARBON, DUAL-COLUMN HIGH-RESOLUTION GC ECD AND HIGH-RESOLUTION GC HIGH-RESOLUTION MS

A method for measurement of toxic coplanar chlorinated biphenyl (CB) congeners in seal tissues is described. Chromatography on Carbopack C efficiently separates the non-ortho substituted coplanar CB congeners CB-37/81/77/126 and CB-169 from the other (mono- and di-ortho Substituted) coplanar CB congeners. In total 31 specific CB congeners are determined by this analytical method. Samples are fractionated, and analyzed by either high resolution dual-column electron capture gas chromatography (HR-GC/ECD) or high resolution gas chromatography/high resolution mass spectrometry (HR-GC/HR-MS) with isotope dilution technique. The method is validated through standard addition experiments, and by use of recovery surrogate standards. The recovery is (85 +/- 16 %; N=78) for the ECD analyses. Corresponding figures for the isotope dilution GC/MS analyses are (79 +/- 14 (CB-77); 80 +/- 15 (CB-126); 83 +/- 17 (CB-169); N=63). Detection limits were 0,1 ng/g for the HR-GC/ECD analysis (undiluted extracts), and 0,005 ng/g by the isotope dilution GC/MS analysis.