Robustness of supercritical fluid extraction (SFE) in environmental studies: Analysis of chlorinated pollutants in tissues from the osprey (Pandion haliaetus) and several fish species

Most commonly used methods for the extraction and subsequent determination of chlorinated pollutants in biotic tissues are time-consuming and require large volumes of hazardous organic solvents. Supercritical fluid extraction (SFE) has recently emerged as a potentially rapid, selective and environmentally-safe alternative. However, its robustness has not been widely evaluated for biological matrices. A SFE-based approach, using CO2 and solid-phase trapping, was successfully applied to the analysis of 644 fish fillets for chlorinated pesticides and PCBs. Resulting extracts required no pre-GC purification steps. Eight mesentery samples, obtained from osprey (Pandion haliaetus) carcasses associated with a mass mortality event in southeast Virginia, were also examined. Bird extracts required simple Florisil column purification prior to GC. Mean total PCB concentrations were much higher in osprey than in fish, 30,400 (SD 12,700) and 414 (SD 911) ug/kg, respectively. Dominant PCBs in the osprey possessed higher degrees of chlorination than those in the fish. Comparison of chromatographic patterns suggested preferential reductions in the concentrations of specific PCBs in the birds. 4,4-DDE was the major pesticide in both birds and fish. Mean concentrations were 8500 (SD 2380) and 812 (SD 127) ug/kg, respectively.