Pressurised solvent extraction of environmental organic compounds in soils using a supercritical fluid extractor

Abstract

The applicability of pressurised solvent extraction (PSE) for the quantitative extraction of different classes of semivolatiles, including polycyclic aromatic hydrocarbons (PAHs), phenols, polychlorinated biphenyls (PCBs) and total petroleum hydrocarbons have been evaluated. For this study a conventional supercritical fluid extraction (SFE) system, the Suprex SFE/50 was adapted to function as a pressurised solvent extraction system. Solid samples were weighed into the SFE thimble and extracted using conventional extraction solvents instead of supercritical carbon dioxide. Parameters such as extraction temperature and effect of modifiers were investigated. Although limited by the 150 °C maximum oven temperature, it was found effective extraction could still be carried out in less than 25 min for all the compounds studied. The technique was applied to different real matrices contaminated with hydrocarbons, PAHs and phenols. Validations of the technique were performed using standard reference materials. Recoveries for these matrices were good (> 75%) and precision was generally less than a 10% RSD. Extensive comparison of this technique with sonication and with microwave assisted extraction (MAE) were made, and recoveries were found to be comparable to MAE and superior to sonication.