Preparation Separation And Adsorption Properties Of Molecularly Imprinted Polymers

Molecular imprinting polymer is an interdisciplinary subject that has been developed from polymerchemistry, material chemistry, analytical chemistry and biochemistry. Being part of super molecularchemistry, molecular imprinting is attracting more and more attention from academic institutions,enterprises and organizations and developing rapidly. Artificially synthesized molecularly imprintedpolymer has high selectivity and specific recognition ability on targeted molecule and has high stability andspecial resistance to acid, alkali and severe environment. Molecularly imprinted polymer has been used assolid phase extractor, high performance liquid chromatograph immobile phase, bionic sensor and naturaldrugs separator by scholars and researchers and thus widely applied to bioengineering, environmentalmonitoring and food industry.This thesis first states the fundamental principles, classification and preparation of molecularimprinting, then reviews its applications in solid phase extraction, environmental monitoring, food industry,pharmaceutical analysis and natural drugs extraction both home and abroad, and finally looks into thefuture of this technology.This thesis is carried out on the basis of the technology of molecular imprinting by using the methodsof bulk polymerization and precipitation polymerization. By adopting triclosan as the template, methacrylicacid as the functional monomer, ethylene glycol dimethacrylate as the cross-linking agent,azobisisobutyronitrile as the initiator and acetonitrile as the solvent, molecularly imprinted polymer oftriclosan is prepared. The shape, size and dispersivity of the imprinted polymer microsphere produced byprecipitation polymerization are observed by SEM. The influence of solvent’s volume on polymermicrosphere in the process of polymerization is discussed. The adsorptive property of imprinted polymermicrosphere is investigated through static adsorption experiment and selective experiment of substrate. Theresults show that both polymers have good selectivity and specific absorptive capacity on triclosan. Theadsorptive capacity and selectivity of the imprinted polymer microsphere produced by precipitationpolymerization are apparently higher than those produced by bulk polymerization. From ScatchardEquation, it can be learned that there are two kinds of affinity locus existing within the scope of consistency. The dissociation constant of high affinity’s binding site Kd1=7.95×10-4mol/L, and the max apparent bindingcapacity Qmax1=19.32μmol/g; while the dissociation constant of low affinity’s binding siteKd2=7.66×10-3mol/L, and the max apparent binding capacity Qmax2=78.28μmol/g. When the analogue oftriclosan is used as competitive substrate, the polymer has good specificity adsorption effect on triclosan,and thus can be adopted in the enriching separation of analogue of triclosan. Packings with molecularlyimprinted polymeric microsphere as the solid phase extraction can separate triclosan from its analogue.With methoxyaniline as the template, methacrylic acid as the functional monomer, ethylene glycoldimethacrylate as the cross-linking agent, azobisisobutyronitrile as the initiator, and acetonitrile as thedissolvent, the molecularly imprinted polymer of4-Methoxyaniline is prepared through the method ofprecipitation polymerization. The structure of polymeric microsphere is represented through the adoption ofSEM. The adsorptive capacity of polymerization system on4-Methoxyaniline and its substrate is studiedthrough static adsorption experiment and selective experiment of substrate. Scatchard analysis is carried outafterwards. The results show that imprinted polymer has good adsorptive capacity and specific recognitionability on template. The solid phase extraction column made by use of molecularly imprinted polymericmicrosphere can be applied to the separation and determination of4-Methoxyaniline in soil.