Development of a simple selective SFE method for the determination of desorption behaviour of PCBs in two Swedish sediments.

A simple selective supercritical fluid extraction (SFE) method was developed for the determination of desorption behaviour of PCBs in sediments. This method was applied to determine the distribution of individual PCB congeners among sites of differing bonding strengths in two Swedish sediments (Lake Järnsjön and Baltic bay Orserumsviken). Four different PCB fractions were distinguished in each sediment by applying consecutively harsher supercritical fluid extraction conditions on the same sample. Even though the two sediments had completely different textures, they showed very similar extraction behaviour. It was shown that, in both sediments, a major part of the PCBs (58% and 65%, respectively) were located at "fast sites", from which they were extractable already with the mildest extraction conditions (60 min, 40 degrees C and 120 bar). Only a small fraction of the PCBs were so tightly bound to the sediments (located at "slow sites"), that they could be extracted only under the harshest conditions (60 min, 150 degrees C and 400 bar). Information of this kind should be of great value for the determination of bioavailability of pollutants in sediments and soils, and it is the author's belief that this technique has the potential to develop into a powerful tool in environmental risk assessment

Pressurised liquid extraction of persistent organic pollutants in environmental analysis

This review updates our knowledge on pressurised liquid extraction, PLE (also known as accelerated solvent extraction and pressurised fluid extraction) of persistent organic pollutants such as polynuclear aromatic hydrocarbons and polychlorinated biphenyls from environmental matrices. The basic experimental set-up is presented, and parameters influencing the extraction process are discussed. PLE can be used for a broad range of applications, and clearly has the potential for replacing tedious classic extraction methods such as Soxhlet extraction. Copyright (C) 2000 Elsevier Science B.V