Extraction of organic contaminants from marine sediments and tissues usingmicrowave energy

In this study, we compared microwave solvent extraction (MSE) to convention al methods for extracting organic contaminants from marine sediments and ti ssues with high and varying moisture content. The organic contaminants meas ured were polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, and polycyclic aromatic hydrocarbons (PAHs). Initial experiments were cond ucted on dry standard reference materials (SRMs) and field collected marine sediments. Moisture content in samples greatly influenced the recovery of the analytes of interest. When wet sediments were included in a sample batc h, low recoveries were often encountered in other samples in the batch, inc luding the dry SRM. Experiments were conducted to test the: effect of stand ardizing the moisture content in all samples in a batch prior to extraction , SRM1941a (marine sediment), SRM1974a (mussel tissue), as well as QA96SED6 (marine sediment), and QA96TIS7 (marine tissue), both from 1996 NIST Inter calibration Exercise were extracted using microwave and conventional method s. Moisture levels were adjusted in SRMs to match those of marine sediment and tissue samples before microwave extraction. The results demonstrated th at it is crucial to standardize the moisture content in all samples, includ ing dry reference material to ensure good recovery of organic contaminants. MSE yielded equivalent or superior recoveries compared to conventional met hods for the majority of the compounds evaluated. The advantages of MSE ove r conventional methods are reduced solvent usage, higher sample throughput and the elimination of halogenated solvent usage. (C) 2001 Elsevier Science Ltd, All rights reserved.