Rapid Extraction of Dioxins in Soils and Sediments Assisted by Microwave

Microwave-assisted extraction (MAE) was applied to the extraction of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin, like polychlorinated biphenyls (DL-PCBs) in soils and sediments. The samples were extracted by MAE with solvents composed of hexane, water and ethanol at a temperature of 125°C for 30 min. The optimized extraction conditions were as follows : hexane (1 mL), water (0.3∼0.5 mL) and ethanol (0.8 mL) for 1 g of an experimental sample. The concentrations of PCDD/DFs and DL-PCBs were equivalent to the results obtained by the conventional method using Soxhlet extraction, and the reproducibility of MAE was below 20% in experiments with four samples of soils and sediment. In addition, our extraction method could drastically reduce the extraction time and facilitate a reduction in organic solvent consumption, compared with the conventional method using Soxhlet extraction.