Facile Way to Prepare a Porous Molecular Imprinting Lock for Specifically Recognizing Oxytetracyclin Based on Coordination

Molecularly imprinted polymers (MIPs) are a kind of synthetic receptor-like materials. They have drawn more and more attention in the past decades. In this work, a facile method was developed to prepare porous magnetic MIPs utilizing metal coordination. The preparation is simply done using conventional oil-in-water emulsifier-free emulsion technology by mixing poly­(styrene-co-itaconic acid), oxytetracyclin (OTC), Cu­(II), and Fe₃O₄ magnetic fluid in one pot with a reaction time of 3 h. The product shows high specificity and selectivity toward OTC, as well as an excellent saturation adsorption capacity (62.567 mg/g). Emphasizing that the imprinting factor is 29, which is the highest one among the reported MIPs to the best of our knowledge. Combined with high-performance liquid chromatography, it was used successfully to determine OTC in pork liver, one of the most complex bio-samples. Recoveries are higher than 91.0% with relative standard deviations less than 4.5% at three spiked levels (n = 3). All evidence testifies that the MIPs based on metal coordination show excellent recognition selectivity and specificity, as well as large rebinding capacity. The strategy holds promise as a reliable, extensible, and versatile way for preparing a metal ion-mediated molecular-imprinting polymer.