GAS CHROMATOGRAPHY-NEGATIVE ION CHEMICAL-IONIZATION MASS-SPECTROMETRYFOR THE DETERMINATION AND IDENTIFICATION OF PLANAR POLYCHLORINATED-BIPHENYLS IN BIOLOGICAL SAMPLES

Planar and mono-ortho substituted polychlorinated biphenyls (PCBs) hav e been identified and quantified at very low concentrations in biologi cal samples (herring and polecat samples) using an off-line combinatio n of column liquid chromatography and gas chromatography-negative ion chemical ionization mass spectrometry (GC-NCIMS). The PCBs generate go od mass spectra dominated by the molecular ion as the base peak. The d issociative electron capture mechanism is more pronounced for the high er chlorinated PCBs. The limits of detection of the planar and mono-or tho substituted PCBs under selected ion monitoring (SIM) conditions ar e 40-100 fg.