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

The applicability of pressurised solvent extraction (PSE) for the quantitat ive 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 convent ional supercritical fluid extraction (SFE) system, the Suprex SFE/50 was ad apted to function as a pressurised solvent extraction system. Solid samples were weighed into the SFE thimble and extracted using conventional extract ion solvents instead of supercritical carbon dioxide. Parameters such as ex traction temperature and effect of modifiers were investigated. Although li mited by the 150 degrees C maximum oven temperature, it was found effective extraction could still be carried out in less than 25 min for all the comp ounds studied. The technique was applied to different rear matrices contami nated with hydrocarbons, PAHs and phenols. Validations of the technique wer e performed using standard reference materials. Recoveries for these matric es were good (> 75%) and precision was generally less than a 10% RSD. Exten sive comparison of this technique with sonication and with microwave assist ed extraction (MAE) were made, and recoveries were found to be comparable t o MAE and superior to sonication.