Rapid Supercritical Carbon Dioxide Extraction Method for Determination of Polychlorinated Biphenyls in Fish

Abstract

An efficient and environmentally friendly supercritical fluid extraction (SFE) method for the determination of naturally contaminated polychlorinated biphenyls (PCBs) in fish tissues is described. The effect of various SFE conditions on lipid content and PCB recovery in fish extracts was studied. Optimal conditions for PCB extraction were nonmodified carbon dioxide at 100°C, pressure of 5000 psi, and flow rate of 2.5 mL/min. Recoveries of PCBs were ≥95% for both naturally contaminated and spiked fish, and this extraction procedure required less than 40 min per sample. By incorporating activated basic alumina with the sample in the extraction process, fish lipid was selectively retained by the adsorbent. The lipid content in the SFE extract varied from <0.1% to 2.2% for the fish samples tested, including those samples with over 30% lipid by weight. In most cases, the remaining lipid was conveniently removed from PCBs by a down-sized Florisil column cleanup. The commonly found chlorinated insecticides, hexachlorobenzene, p,p′-DDE, and mirex were also extracted and determined simultaneously with PCBs.