Pressurised hot water extraction and thermal desorption of polycyclic aromatic hydrocarbons from sediment with use of a novel extraction vessel

Abstract

A novel extraction vessel was constructed for pressurised hot water extractions (PHWEs). The recoveries of polycyclic aromatic hydrocarbons (PAHs) in sediment obtained with the vessel were comparable with those obtained with a commercial vessel using steam. Recoveries of PAHs obtained by PHWE were compared with recoveries obtained by thermal desorption to evaluate the roles of water and temperature in the extraction. Liquid water and steam were tested in a temperature range of 200–300 °C and thermal desorption with nitrogen at temperatures 200–350 °C. At 300 °C, the best results were obtained with steam, while the recoveries obtained with liquid water and nitrogen were comparable to each other. The recoveries achieved with nitrogen at 300 °C were surprisingly good, about 85% of the values obtained with steam. Recoveries were good for most of the PAHs relative to the certified reference values and they were in accord with values obtained earlier in our laboratory.