Comparison of Different Extraction Techniques of PCBs from Sediment Samples Using the Isotope Dilution Mass Spectrometry Technique

In this work, problems that may occur during determination of trace levels of polychlorinated biphenyls in sediment samples are described. The main error sources are connected with extraction of analytes prior to final determination. During model studies, polychlorinated biphenyls have been extracted from sediment reference material (METRANAL 2) with the use of different solvents (dichloromethane, hexane, and toluene); the process has been enhanced by mechanical shaking or ultrasound. Seven selected PCBs (PCB 28, 52, 101, 118, 138, 153, and 180, according to IUPAC) were determined in extract samples by the GC-MS technique and using the isotope dilution mass spectrometry (IDMS) technique. The results suggest that the best solvents for the isolation of PCB group compounds from sediment samples are dichloromethane and toluene. On the basis of results obtained it can be stated that increasing the number of extraction cycles to 10 and prolonging the sample ultrawave bath to 40 min do not affect the results obtained; thus, the accuracy of the procedure doesn't change from the statistical point of view.