Thermosensitive molecularly imprinted polymers based on magnetic nanoparticles for the recognition of sulfamethazine

In this study, a thermosensitive molecularly imprinted polymer (TMIP) was successfully synthesized for the selective recognition of sulfamethazine (SMZ) on the surface of magnetic nanoparticles. N-Isopropylacrylamide (NIPAM) as the thermosensitive monomer, methacrylic acid (MAA) as the functional monomer, ethyleneglycol dimethacrylate (EGDMA) as the cross-linking agent and azodiisobutyronitrile (AIBN) as the initiator were selected to prepare the TMIPs. The thermosensitive magnetic molecularly imprinted polymers were sensitive to the temperature and the adsorption/desorption process could be controlled by changing the temperature because the thermoresponsive monomer NIPAM can undergo a reversible volume transition between the swollen and collapsed phases. Moreover, the resultant TMIPs showed high adsorption capacity and specific affinity towards SMZ. The adsorption capacity of TMIPs reached the maximum when the adsorption temperature was around the LCST of NIPAM. The magnetic property of TMIPs provided fast separation while the thermoresponsive property offered simple elution for templates. Finally, the imprinted polymers were used for the enrichment of SMZ from real water with recoveries ranging from 83.2% to 96.8% determined by high performance liquid chromatography. The results indicated that the TMIPs were efficient for thermally modulated capture and release of the template, which enable its application for trace sulfamethazine in complicated samples.