Effect of solvent on extraction of polychlorinated biphenyls and polychlorinated dibenzodioxins from charcoal

Abstract

The effect of solvent on the extraction of two polychlorinated biphenyls (PCBs) and five polychlorinated dibenzodioxins (PCDDs) from charcoal is investigated and the variations in recoveries of these analytes are explained. The extraction is performed using chromatographic elution, ultrasound-assisted extraction (UAE) of probe- and bath-type, supercritical fluid extraction (SFE), and enhanced-fluidity liquid extraction (EFLE). In each of the extraction methods used, only the use of isopropanol-toluene mixtures shows higher recoveries than the use of toluene alone. Higher recoveries are obtained using EFLE, compared with other extraction methods, even though the same amount, i.e., 30mL, of extraction solvent is used, because higher temperature is applied under higher pressure. After each extraction, chromatographic interferences are removed through a multilayer silica gel column clean-up. The quantification of PCBs and PCDDs is performed using HPLC-UV.