Preparation And Adsorption Property Of Magnetic Molecularly Imprinted Polymers

Moleclular imprinting technique has become a promising way to prepare moleclularly imprinted polymers (MIPs) with tailored selectivity for analytes. MIP prepared by moleclular imprinting technique is a new polymer material with many advantages, such as excellent selectivity, high adsorption, high efficieacy in chromatography and easy design. However, traditional MIPs have many limitations, such as incomplete template removal, low-affinity binding and slow mass transfer. Therefore, researchers develop surface MIPs on the surface of matrix using surface moleclular imprinting technique, which enables the template-imprinting sites to situate at the surface or in the proximity of the polymers, providing the advantages of favorable selectivity and fast association/dissociation kinetics. Therefore, surface moleclular imprinting technique can be employed to synthesize imprinted polymers with high selectivity and amount of adsorption for targets. Magnetic nanoparticle had become more and more important in analytical chemistry, bioscience and medicine due to its excellent magnetic property. Therefore, the core-shell magnetic molecular imprinted polymer microspheres prepared by surface moleclular imprinting on magnetic nanoparticle have combined the advantages of both molecularly imprinted polymer and magnetic polymer microspheres, with good superparamagnetism and high selective adsorptivity.In this paper, magnetic molecular imprinted polymers (GSH-MMIPs and Qu-MMIPs) for glutathione (GSH) specific recognition and quercetin (Qu) specific recognition with core-shell structure, were prepared via surface moleclular imprinting technique respectively, in which GSH and Qu as template molecules and Fe3O4nanoparticles (NPs) as magnetic carrier. The as-prepared polymers were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, vibrating sample magnetometer (VSM). The research contents in details were as follows:(1) The GSH-MMIPs for GSH specific recognition were prepared via one-step polymerization process, in which GSH as template molecule, N-vinylpyrrolidone and acrylamide as functional monomers,N, N’-methylene bisacrylamide as crosslinker, H2O2-Vc as initiator and Fe3O4nanoparticles (NPs)as magnetic carrier. The effects of the molar amount of Fe3O4, monomers and crosslinker, the dosage of initiators, polymerization time and temperature on adsorption amount were optimized by L18(37) orthogonal test. The optimum conditions were obtained that n(Fe3O4) is1mmol, n(GSH):n(AM+NVP) is1:4, n(AM+NVP):n(MBA) is1:4, the dosage of initiators is2%, polymerization time is28h, polymerization temperature is50℃. GSH-MMIPs prepared at the optimum conditions presented favourable adsorption of GSH with a maximum amount of9.9416mg/g. The as-prepared polymers were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM). The adsorption property of GSH-MMIPs onto target molecules was investigated by high performance liquid chromatograph (HPLC). The results showed that magnetic molecularly imprinted polymers had good recognition performance for the target molecules. This protocol was further employed for the extraction and separation of GSH from an aqueous solution.(2) The Qu-MMIPs for Qu specific recognition were prepared via one-step polymerization process, using Qu as template molecule, N-vinylpyrrolidone and acrylic acid as functional monomers, N, N’-methylene bisacrylamide as crosslinker, H2O2-Vc as initiator and Fe3O4nanoparticles (NPs) as magnetic carrier. The as-prepared polymers were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM). The results demonstrated that an imprinted polymer layer was successfully coated onto the surface of modified Fe3O4NPs, resulting in a narrow diameter distribution and good magnetic responsibility. The adsorption performance of Qu-MMIPs onto imprinting molecules was investigated by high performance liquid chromatograph (HPLC). The results showed that quercetin magnetic molecularly imprinted polymers had good recognition performance for the quercetin molecules. This method was further employed for the extraction and separation of Qu from an anhydrous ethanol solution.