Multi-template imprinted polymers for simultaneous selective solid-phase extraction of six phenolic compounds in water samples followed by determination using capillary electrophoresis

Novel multi-template molecularly imprinted polymers (mt-MIPs) with six phenolic compounds as the template, namely phenol, 4-chlorophenol (4-CP), 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), were prepared by precipitation polymerization and used as the adsorbents of solid-phase extraction (SPE), and coupled with capillary electrophoresis (CE) for the simultaneous selective extraction, separation and determination of trace phenolic compounds in water samples. The resultant mt-MIPs exhibited uniform spherical morphology, large specific surface area and high thermal stability, and offered high selectivity towards the six template phenolic compounds. Various parameters affecting the molecularly imprinted SPE (MISPE) efficiency were investigated in detail, and excellent CE separation was realized within 7 min. Good linearity was obtained in the range of 1–200 μg L⁻¹ for phenol and 4-CP, and 1–300 μg L⁻¹ for 2,4,6-TCP, 2,4-DCP, 2-CP and 2,6-DCP. High sensitivity was attained with low limits of detection and quantification ranging from 0.17 to 0.31 μg L⁻¹ and 0.57 to 1.03 μg L⁻¹, respectively. Satisfactory recoveries for spiked reservoir water, river water, tannery wastewater and tap water samples were achieved in the range of 82.13–105.63% with relative standard deviations within 1.68–6.96%. The developed MISPE-CE method proved practically feasible for simultaneous selective extraction/enrichment, separation and sensitive determination of multiple targets in complicated aqueous matrices.