Determination of selected polychlorinated biphenyls in water samples by ultrasound-assisted emulsification-microextraction and gas chromatography-mass-selective detection

Ultrasound-assisted emulsification-microextraction (USAEME) procedure was developed for the determination of selected polychlorinated biphenyls (PCBs) in 10mL of water samples by gas chromatography-mass-selective detection. After determination of the most suitable solvent and extraction time, several other parameters including solvent volume, centrifugation time and ionic strength of the sample were optimized using a 23 factorial experimental design. The optimized USAEME procedure used 200 mu L of chloroform as extraction solvent, 10 min of extraction with no ionic strength adjustment at 25 degrees C and 5 min of centrifugation at 4000 rpm. The limits of detection ranged from 14 ng L(-1) (for PCB153) to 30 ng L(-1) (for PCB101). Recoveries of PCBs from fortified distilled water are over 80% for three different fortification levels between 0.1 and 5 mu g L(-1) and relative standard deviations of the recoveries are below 10%. The performance of the proposed method was compared with those involving traditional liquid-liquid extraction (LLE) and solid phase extraction (SPE) on the real water samples (i.e., tap and well water as well as domestic and industrial wastewaters, etc.) and comparable efficiencies were obtained. The proposed USAEME procedure has been demonstrated to be viable, simple, rapid and easy to use for residue analysis of PCBs in water samples. (C) 2009 Elsevier B.V. All rights reserved.