Optimisation and comparison of microwave-assisted extraction and Soxhlet extraction for the determination of polychlorinated biphenyls in soil samples using an experimental design approach

Optimisation of microwave-assisted extraction (MAE) for the extraction of p olychlorinated biphenyls (PCBs) from soil samples has been accomplished usi ng an experimental design approach. Variables studied have been: percentage of acetone (v/v) in an acetone:n-hexane mixture, solvent volume, extractio n time, microwave power and pressure inside the extraction vessel. Five sam ples of a certified soil (CRM 481) have been extracted under the optimum co nditions of the developed method and the results have been compared to thos e obtained by Soxhlet extraction. Good recoveries (> 95%) have been obtaine d for all the PCBs studied. All extracts have been analysed by gas chromato graphy/mass spectrometry (GC/MS) and an optimum determination method for th e electron impact mass spectrometric (EIMS) has also been developed. (C) 19 99 Elsevier Science B.V. All rights reserved.