Development of a subcritical fluid extraction and GC-MS validation method for polychlorinated biphenyls (PCBs) in marine samples.

This paper describes a new procedure for extracting polychlorinated biphenyls (PCBs) from marine samples using subcritical 1,1,1,2-tetrafluoroethane (R134a). The extraction procedure was optimized at temperatures varying from 20 to 70°C and pressures ranging from 3 to 15 MPa. The volume of the co-solvent was then optimized using 1,1,1,2-tetrafluoroethane (R134a) as the subcritical phase. PCBs were characterized by GC-MS using the optimized conditions of 3 MPa, 30°C, and a co-solvent volume of 6 mL. The average yields of PCBs from subcritical fluid extraction of spiked oyster samples were measured and found to be greater than 90%, with relative standard deviations (RSD) of less than 10%. Detection limits of this method were in the range of 0.045-0.108 ng/g of dry mass. The method was compared to Soxhlet extraction and then applied for monitoring PCBs in oysters from Qingdao, Shandong, China.