Membrane-assisted solvent extraction of polychlorinated biphenyls in river water and other matrices combined with large volume injection-gas chromatography-mass spectrometric detection.

Membrane-assisted solvent extraction was applied to the determination of polychlorinated biphenyls (PCBs) in aqueous samples. The apparatus of membrane-assisted solvent extraction consisted of a 20 ml headspace vial which was filled with 15 ml of the aqueous sample. The membrane bag was placed into the vial and the extraction took place in an agitator. After extraction, the analytes were transferred into the inlet of a gas chromatograph by large volume injection. A mass-selective detector was used. The whole procedure was fully automated. The work included optimization of the extraction conditions (stirring rate and extraction time) and the influence of matrix effects like salt addition and the presence of organic solvents was studied. Calibration was performed using injection volumes of 100 and 400 microl. Several parameters like linearity and reproducibility of the procedure were determined. At optimized conditions detection limits in the ng/l range were achieved. The effectiveness of the method towards real samples was tested by analyzing river water, white wine and apple juice.