Determination of hydroxylated polychlorinated biphenyls by offline solid-phase extraction-liquid chromatography-tandem mass spectrometry using a molecularly imprinted polymer as a sorbent for sample preconcentration.

Hydroxylated polychlorinated biphenyls (OH-PCBs) can be detected by liquid chromatography-mass spectrometry coupled to solid-phase extraction (SPE) using a dummy molecularly imprinted polymer (DMIP) as a sorbent. The DMIP is prepared by using an analogue of OH-PCBs (i.e., 4, 4-dihydroxybiphenyl) as a dummy template, to avoid the leakage of the target molecules. The DMIP-SPE sorbent shows good recoveries for OH-PCBs at pH 11 due to the charge-assisted hydrogen bondings between OH-PCBs and the DMIP. It has been found that the DMIP is much more effective and selective than the traditional C18-SPE method. The sample pH, polymer dosage, elution solvent and volume have been optimized for higher recoveries. Under the optimum experimental conditions, OH-PCBs can be detected in the linear concentration range of 0.05-1.0 pM, with the detection limits ranging from 11 fM to 82 fM for 4'-OH-CB 9, 4'-OH-CB 30, 4'-OH-CB 61, 4'-OH-CB 106 and 4'-OH-CB 112. The proposed system has been successfully applied to the determination of trace OH-PCBs in spiked water samples with recoveries in the range of 89-110%.