Applications Of Molecular Imprinting On Capillary Electrochromatographic Monolith And Preparation Of Microspheres

Molecular imprinting is a technique for the preparation of synthetic polymers with predetermined selectivity, good specific recognition and high affinity capacity to the template molecule. It has been well established and widely used in a variety of molecular recognition-based applications, such as separation media, artificial antibody mimics and sensing devices in recent years. The rationale of molecularly imprinting is arranging polymerizable functional monomers around a template molecule. To achieve this, the template molecules and functional monomers are dissolved in the solvent to form complexes utilizing non-covalent interactions or covalent interactions. The complexes are then incorporated by polymerization into a highly cross-linked macroporous polymer matrix. After extraction of the template molecules, complementary recognition sites are left in the polymer network which can rebind template molecule specifically. Molecularly imprinted monolithic column for capillary electrochromatography is a novel technology that combines the advantages of molecularly imprinting and capillary electrochromatography. Precipitation polymerization is a convenient way to produce molecluarly imprinted polymer microspheres.In this thesis, the aminoantipyrine MIP-CEC monolithic column was prepared by in situ thermal-polymerization in a 100μm I.D. silica column. The effect of different CEC conditions on retention time and separation factor of aminoantipyrine and antipyrine was studied. The mechanism of molecular recognition was discussed. Aminoantipyrine and antipyrine were separated in 18 min and the separation factor was 1.37. The mobile phase was MeCN (15%, v/v)/NaH₂PO₄(5mmol/L), pH=7.0.The aminopyrine was employed as template to prepare MIP-CEC monolithic column. The effect of the proportion among template molecular, functional monomer and cross linker and the polymerization time on the separation ability of MIP-CEC monolithic column is studied. The appropriate conditions to produce monolithic column are template: functional monomer: cross linker=1:4:20, polymerization time was 12h. Molecularly imprinted polymer microspheres were prepared by precipitation polymerization. The effect of synthesis conditions, including the kind of solvent, polymerization temperature, the concentration of template and initiator, rotational speed and pre-polymerization time, on the characteristics of the molecularly imprinted polymers microspheres was studied. The rebinding experiments showed that the molecularly imprinted polymers microspheres had good specific recognition and higher affinity capacity.