Facile construction of magnetic hydrophilic molecularly imprinted polymers with enhanced selectivity based on dynamic non-covalent bonds for detecting tetracycline

While a number of methods towards water-compatible molecularly imprinted polymers (MIPs) have been reported, new strategies affording simple preparation process and enhanced adsorption selectivity towards templates are needed to promote the further development of MIPs. Herein, we propose a novel method for preparing water-compatible MIPs (Cu-CMMIPs) with enhanced selectivity for tetracycline (TC) based on the dynamic physically cross-linking. The as-synthesized styrene-methacrylic acid copolymer was introduced as hydrophilic cross-linking functional monomers instead of conventional functional monomers and cross-linkers, thus eliminating the need of optimizing the cross-linkers/functional monomers ratio. The copper ions served as cross-linker, and in view of increased adsorption capacity and enhanced selectivity of the prepared MIPs, it was hypothesized that the introduction of copper ions would result in the strong interaction between the polymer network and TC. The imprinting process of TC is carried out by direct physical cross-linking of active groups of TC with functional groups of the polymeric network. The resultant Cu-CMMIPs exhibited excellent hydrophilicity, outstanding adsorption capacity and selectivity towards TC in water. Finally, the developed Cu-CMMIPs were applied as magnetic solid phase extraction adsorbents for the specific recognition of TC in environmental water combined with HPLC-DAD detection (LOD is 3.75 μg/L and the recoveries ranging from 91.2 % to 101.3 %). The proposed concept in this work for fabrication of MIPs with facile preparation process, enhanced selectivity and satisfactory hydrophilicity would inspire more ideas to implement in cost-effective adsorbents construction.