Preparation And Characterization Of Novel Surface Molecularly Imprinted Polymer Microspheres

Abstract:Magnetic Fe3O4were used as supporter, combined with surface molecular imprinting technology, magnetic dummy molecularly imprinted polymers, thermo-responsive magnetic molecularly imprinted polymers and magnetic molecularly imprinted polymers that based on DD-AA double hydrogen bonding array were synthesized with the addition of dummy template, thermo-responsive monomer and novel functional monomers, all these materials displayed high selectivity and good adsorption capacity. The successful preparation and application of the novel surface molecularly imprinted polymers have laid a solid foundation for a wide range application of molecular imprinting technology and promoted its better development. The full text includes four chapters:The introduction in the first chapter includes four parts. First, simple concept and synthetic methods of molecular imprinting technology were introduced, then elaborated the functional monomer selection of imprinted polymerization and the development situation. Next, the application of magnetic surface molecularly imprinted polymers in extraction of natural active ingredients in the product was displayed. Finally, some of the innovations and theme basis of this paper were discussed.Magnetic dummy molecularly imprinted polymers applied in separation and enrichment salicylic acid in Actinidia chinensis were studied in the second chapter. Compounds with strong intramolecular hydrogen bonds (e.g. salicylic acid) have weak intermolecular hydrogen bonding interaction between theaam and functional monomers in the imprinting process. Consequently, the corresponding molecularly imprinted polymers (MIPs) have no specific adsorption ability. Here the first magnetic dummy molecularly imprinted polymers (MDMIPs) based on benzonic acid as dummy template are successfully developed and evaluated with respect to the applications in selective enrichment and analysis of salicylic acid from complex mixtures. Various parameters affecting absorption/desorption were evaluated for achieving optimal recovery and reducing non-specific interactions. The prepared MDMIPs showed high adsorption capacity, good selectivity, rapid kinetic binding (40min) and magnetic separation (5s), high reproducibility (RSD<4%for batch-to-batch evaluation) and stability (only4%decrease after five cycles).In the third chapter of the dissertation, thermo-responsive magnetic molecularly imprinted polymers (TMMIPs) for selective recognition of curcuminoids with high capacity and selectivity have firstly been developed are discussed. The resulting TMMIPs were characterized by TEM, FT-IR, TGA, VSM and UV, which indicated that TMMIPs showed thermo-responsiveness [lower critical solution temperature (LCST) at33.71℃] and rapid magnetic separation (5s). The polymerization, adsorption and release conditions were optimized in detail to obtain the highest binding capacity, selectivity and release ratio. We found that the adopted thermo-responsive monomer [N-isopropylacryamide (NIPAm)] could be considered not only as inert polymer backbone for thermo-responsiveness but also as functional co-monomers combination with basic monomer (4-VP) for more specific binding sites when ethanol was added in binding solution. The adsorption process between curcumin and TMMIPs followed Langumuir adsorption isotherm and pseudo-first-order reaction kinetics. The prepared TMMIPs also showed high reproducibility (RSD<6%for batch-to-batch evaluation) and stability. Subsequently, the TMMIPs were successfully applied for selective extraction of curcuminoids from complex natural product, Curcuma longa.The magnetic surface molecularly imprinted polymers based on double DD-AA hydrogen array were studied in the fourth chapter. All synthesis steps were the same as the third section except imprinting process,2,4-dianimo-6-vinyl-S-triazine is excavated as a novel functional monomers and curcumin as template molecular. Double DD-AA hydrogen bond interaction produced between carbonyl groups and amino, the adsorption capacity of MMIPs was close to that of TMMIPs, indicating that double DD-AA hydrogen bond interaction between novel functional monomer and template molecular were reached the expected effect and almost to the complex functional monomer (4-VP and NIPAm).