Focused microwave (FMW) extraction of polycyclic aromatic hydrocarbons (PAHs) from plant bioindicators, comparison with classical techniques

Extraction efficiencies of polycyclic aromatic compounds (PAHs) from spruce needles (Picea abies) obtained by recently introduced "focused microwave a ssisted (FMW) extraction" (i) and conventional methods represented by extra ction enhanced by sonication (ii) and Soxhlet extraction (iii) were compare d. n-Hexane:acetone (azeotropic ratio, 53.5 wt % of acetone) extraction mix ture was used in all experiments. The influence of various parameters (extr action time, intensity of irradiation, moisture content) both on the recove ries of PAHs from spruce needles (Picea abies) and the amount of co-isolate d matrix components potentially interfering within the determinative step w as examined. The mean extraction efficiencies of PAHs obtained by FMW extra ction and sonication were found to be lower (82 % and 75 %, respectively) c ompared the extraction in Soxhlet apparatus (equal 100 %).