Development of a new liquid phase microextraction method using a switchable solvent for the determination of polychlorinated bi-phenyls (PCBs)

Polychlorinated biphenyls (PCBs) are a class of synthetic organic compounds that are hazardous due to their chemical and thermal stability, hydrophobicity and toxic properties [1-2]. PCBs often exist at trace levels of concentration in the environment, so an effective pretreatment step is necessary for their preconcentration before quantification. In this study, a new method was successfully developed for the simultaneous determination of seven polychlorinated biphenyls in aqueous samples with switchable hydrophilicity solvent based liquid phase microextraction coupled to GC-MS detection. Triethylamine (TEA) was used as extraction solvent with switchable polarity, which can be miscible/immiscible upon the changes of pH of sample solution. The factors influencing the extraction efficiency, including type and volume of extraction solvent, pH and volume of aqueous sample, extraction time, and salt addition were investigated and optimized. Under the optimized conditions, good linearity (0.5-150 μg/L) and limits of detection (0.15 μg/L) were obtained for the PCBs by the proposed method. Also, the relative standard deviations (RSDs) were calculated between 5.2 and 6.4 %. In addition, enrichment factors (EFs) and extraction recoveries (ERs) were obtained in the ranges of 30.46-32.10 and 76.15-80.25 respectively. Finally, the proposed method was successfully applied for the analysis of PCBs in various water samples with excellent relative recoveries (RRs, 96.30-102.60).