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Supercritical fluid extraction (SFE) is a promising technique for the extraction of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (2,3,7,8‐TCDD) from environmental matrices such as contaminated sediments. The ability of SFE to solubilize many organic contaminants is well documented in industrial processes but its analytical applications were exploited just recently. In this study supercritical carbon dioxide and nitrous oxide and their mixtures with 2% methanol were used to extract 2,3,7,8‐TCDD from aquatic sediments. An attractive feature of this process is that the carbon dioxide, being a virtually inert fluid, leaves no solvent residue on the processed sediment. Almost 100% of the 2,3,7,8‐TCDD can be extracted from a sediment spiked with 200 μg/kg 2,3,7,8‐TCDD in 30 minutes by using supercritical carbon dioxide + 2% methanol. Cleanup procedure is compared with the Soxhlet extraction procedure currently used as a standard method for extracting dioxins from sediment samples.

SummaryThe microwave energy produced by a high intensity microwave oven was used to extract polychlorinated biphenyls (PCB) from water samples. This static method was compared with liquid-liquid extraction to determine the optimum and limiting conditions in extraction processes. The sample size and sample container shape determine the temperature profiles in the sample. Using a 500 rnL sample size, the detection limit is in the low ng/L range when an electron capture detector is employed.