Determination of polychlorinated biphenyls in biotic matrices using gas chromatography--microwave-induced plasma atomic emission spectrometry.

Basic parameters associated with practical application of gas chromatography coupled with microwave-induced plasma atomic emission spectrometric detection GC-MIP-AED in the determination of seven "indicator" polychlorinated biphenyls (PCBs) in biotic matrices were evaluated. The detection limit for chlorine (Cl-479) was found to be 0.54 pg/s. Under the conditions used for sample analysis (1 microliters of purified extract injected into the GC-MIP-AED system represented 2.5 mg of original fat), this value corresponded approximately to 0.15 mg/kg of the respective congeners in fat. The detector response was linear within the tested range of 0.5-10 ng of each injected PCB. The relative standard deviation of repeated injections for the lowest concentration level of 0.5 ng of PCB per injection ranged between 10.5 and 34.4% depending on the chlorine content of the individual analytes. The results demonstrate a high selectivity of chlorine detection. Carbon (C-496) chromatograms recorded simultaneously demonstrated the efficiency of the clean-up step used. Quantitative results (analytes at levels of 0.1-1 mg/kg) obtained with the atomic emission detector did not differ significantly from those recorded with a conventional electron-capture detector.