Preparation Of Magnetic Surface Molecularly Imprinted Polymers And Its Recognition Character

This paper via surface molecular imprinting technique prepared 4-methyl imidazole molecularly imprinted polymer used magnetic Fe₃O₄ as the substrate, the adsorption performance of the molecularly imprinted polymer and its detail recognition performance. Fe₃O₄@SiO₂ as the substrate prapred melamine surface molecularly imprinted materials and Thiamphenicol surface molecularly imprinted materials. Studied the identification performance of the MMIPs, MMIPs directly added to the sample as the magnetic extractant, extraction and separation system does not need additional centrifuge and filter after simplifying the preprocessor and samples combined with HPLC analysis, analysis to detect the contents of it.Experiment is divided into several parts: 1.4-methyl imidazole magnetic molecularly imprinted polymer was prepared by using 4-methyl imidazole as template molecule, methacrylic acid （MAA） as functional monomer and Fe₃O₄ magnetic fluid. The polymer was characterized by means of FT-IR analysis, X-ray diffraction （XRD） analysis, transmission electron microscopy （TEM） and vibrating sample magnetometer（VSM）. The results demonstrated that an imprinted polymer layer was successfully coated onto the surface of modified Fe₃O₄ nanomaterials, resulting in a narrow diameter distribution and good magnetic responsibility. By UV spectrophotometric method to study the adsorption performance of magnetic molecularly imprinted polymer, the specific adsorption equilibrium and selectivity were evaluated by batch rebinding studies. The static adsorption equilibrium experiment data from get Scatchard fitting curve drawing, through curve fitting analysis it was concluded that the molecularly imprinted polymer in different binding sites.The corresponding maximum adsorption capacities of 4-MI onto 4-MI-Fe₃O₄@MIP were 40.31 mg/g and 38.50 mg/g, and the dissociation constants were7.25×10-4 mol/L and 7.84×10-4 mol/L, respectively. The kinetic experimental data were correlated with second-order kinetic model. The magnetic molecularly imprinted polymer was used for adsorption of 4-methyl imidazole in environmental water samples, and good results were obtained.2. In this work, a simple and selective method was successfully developed for the determination of Melamine （MEL） in milk using magnetic surface molecularly imprinted polymer （MMIPs） as sorbent. The MMIPs has been prepared by using MEL as template molecule, methacrylic acid （MAA） as functional monomer and Fe₃O₄@ SiO₂ as magnetic support. The polymer was characterized by means of FT-IR analysis, X-ray diffraction （XRD） analysis,Thermogravimetric Analysis （TGA） and vibrating sample magnetometer （VSM）. The results demonstrated that an imprinted polymer layer was successfully coated onto the surface of modified Fe₃O₄ nanomaterials, resulting in a good magnetic responsibility. The UV spectrophotometry was used to demonstrate the interaction between MEL and MAA. It was found that one MELwas entrapped by two MAA molecules, which was the main existing form of subject and object. By UV spectrophotometric method to study the adsorption performance of magnetic molecularly imprinted polymer, the specific adsorption equilibrium and selectivity were evaluated by batch rebinding studies. Through Scatchard curve fitting analysis it was concluded that the molecularly imprinted polymer in different binding sites. The magnetic molecularly imprinted polymer has been applied to the analysis of melamine in real samples, and good results were obtained.3. Thiamphenicol with specific recognition of magnetic surface molecularly imprinted polymer was prepared by using Thiamphenicol as template molecule, methacrylic acid （MAA） as functional monomer and Fe₃O₄@ SiO₂ as magnetic support. The polymer was characterized by means of FT-IR analysis, X-ray diffraction （XRD） analysis,Thermogravimetric Analysis （TGA） and vibrating sample magnetometer （VSM）. The results demonstrated that an imprinted polymer layer was successfully coated onto the surface of modified Fe₃O₄ nanomaterials, resulting in a good magnetic responsibility. The UV spectrophotometry was used to demonstrate the interaction between TAP and MAA. It was found that one TAP was entrapped by one MAA molecules, which was the main existing form of subject and object. By UV spectrophotometric method to study the adsorption performance of magnetic molecularly imprinted polymer, the specific adsorption equilibrium and selectivity were evaluated by batch rebinding studies. The obtained results revealed that the extraction recoveries of thiamphenicol from real samples were in the range of 92.6%-95.6%, with relative standard deviation （RSD） were 1.1 %～3.2%. The limit of detection （LOD） of this new method was 10 ug/L. The magnetic molecularly imprinted materials can be repeatedly used several times, the recoveries ratios were much than 85%.. These results indicated that magnetic molecularly imprinted materials can be combined with HPLC on-line detection of trace the thiamphenicol in the milk.