Molecularly imprinted polymers for dispersive solid-phase extraction of phenolic compounds in aqueous samples coupled with capillary electrophoresis.

A simple and sensitive method for the simultaneous determination of seven phenolic compounds in aqueous samples was developed by dispersive solid-phase extraction (DSPE) coupled with capillary electrophoresis (CE), namely phenol, 4-chlorophenol (4-CP), pentachlorophenol (PCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,4-dichlorophenol (2,4-DCP), 2-chlorophenol (2-CP) and 2,6-dichlorophenol (2,6-DCP). Molecularly imprinted polymers (MIPs) prepared by precipitation polymerization with 2,4,6-trichlorophenol (2,4,6-TCP) as template were used as DSPE sorbents to selectively adsorb the phenols. Various parameters affecting the extraction efficiency were evaluated and excellent CE separation was achieved within 13.5 min by using 15 mmol/L borate buffer containing 15% (v/v) methanol at pH = 9.8. Under the optimized conditions, good linearity was obtained in the range of 2-200 μg/L for phenol, 2,4-DCP and 2,6-DCP, 2-300 μg/L for 4-CP and 2-CP, 1.5-150 μg/L for PCP, and 2-400 μg/L for 2,4,6-TCP, with the correlation coefficient (R2 ) higher than 0.9938. Limits of detection and limits of quantification were in the range of 0.18-0.44 μg/L and 0.59-1.45 μg/L, respectively. The developed MIPs-DSPE-CE method was also successfully applied to determine the seven phenolic compounds in lake, tap, seawater and tannery wastewater. The average recoveries at three different spiked levels ranged from 70.75 to 106.7% with the relative standard deviations of 1.15-6.28%.