Extraction of polycyclic aromatic hydrocarbons from soils: A comparison between focused microwave assisted extraction, supercritical fluid extraction, subcritical solvent extraction, sonication and Soxhlet techniques

Focused microwave, supercritical fluid and subcritical solvent extraction methods were compared with the classical Soxhlet and sonication procedures for routine determination of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil. In each case the extraction efficiency was examined for 5 series (n = 5) of 15 PAHs. Quantitative and pragmatic arguments were considered toward the selection of an appropriated method for routine analysis. The new extraction techniques yielded interesting alternatives to conventional ones, not least since their quantitative results proved more easily reproducible than those afforded either by Soxhlet and sonication. Besides, the automation of extraction systems is a crucial criterion for routine analysis.