Solid-phase extraction of chlorophenols in seawater using a magnetic ionic liquid molecularly imprinted polymer with incorporated silicon dioxide as a sorbent

A type of magnetic ionic liquid based molecularly imprinted polymer coated on SiO2 (Fe3O4@SiO2@IL-MIPs) was prepared with 1-vinyl-3-ethylimidazole ionic liquid as functional monomer, and 1,4-butane-3,3'-bis-1-ethylimidazole ionic liquid as cross linker, 4-Chlorophenol as template was successfully applied as a selective adsorbent for selective extraction of 5 chlorophenols in seawater samples by using the magnetic solid-phase extraction (MSPE) method. 11 types of Fe3O4@SiO2@IL-MIPs were synthesized and investigated for their different compositions of functional monomer (such as [C(2)min][Br], [C(2)min][BF4], [C(2)min][PF6], acrylamide, methacrylic acid and 4-vinyl pyridine) and cross-linker (such as [C(4)min(2)][Br], [C(4)min(2)][BF4], [C(4)min(2)][PF6], divinylbenzene, and ethylene glycol dimethacrylate), respectively. The [C(2)min][BF4] and [C(4)min(2)][PF6] based Fe3O4@SiO2@IL-MIP with the highest extraction efficiencies was applied to the optimization experiment of MSPE process (including extraction time, adsorbent mass and desorption solvents). Good linearity was obtained with correlation coefficients (R-2) over 0.9990 and the relative standard deviations for the intra-day and inter-day determination were less than 3.10% with the extraction recoveries ranged from 85.0% to 98.4%. The results indicated that the proposed Fe3O4@SiO2@IL-MIPs possesses great identification and adsorption properties, and could be used as a good sorbent for selective extraction of CPs in environment waters. (C) 2018 Elsevier B.V. All rights reserved.