Preparation Of Molecularly Imprinted Polymer And Its Recognition Properties Of Applied Research

Molecular imprinting technology (MIT) has been a hot issue to investigate because which can provide the polymers that have high recognizetion and selectivity properties to objective molecular. On the base of the review to the progress of MIT, following experiments were carried on.1 Using cinchonine(CN) as template molecule, spherical cinchonine imprinting polymers were synthesized by precipitation Polymerization. Their mechanisms of recognition and binding selectivity were explored by IR, equilibrium binding, Scatchard analysis. This could give an impetus to investigate the application of MIP further. The separation factor α between cinchonine(CN) and cinchonidine(CD) was 1.86 by the CN-MIPs, but the factor only 1.02 by non-imprinted polymer(NIP). Scatchard analysis showed that two sites were produced in the polymer matrix and their equilibrium constants were calculated to be 131.43μmol/L, 2.32mmol/L respectively. And the spherical particles were uniform and stable, their average size was 0.5μm.2 CN imprinting polymer was prepared by bulk polymerization. Conditions of polymerization and operation when the MIP used as chromatography station-phase were selected and optimized. The results showed that better effect could be achieved under 0 ℃ with ultraviolet light in 366nm when the ratio of template molecule to monomer was 1 .' 4. Diastereoisomers of CN and CD could be separated on the MIP column and the resolution factor was 1.82 using CH₃OH-CHCl₃ (9:1,v/v) as mobile phase in the flow rate of 0.4mL/min. The operation conditions to synthesize the polymer were easy to control and its reproduction was nice.3 On the base of the former researches, imprinted polymer membranes(IPM) were prepared by UV light initiation under 0 ℃. In order to get a better membrane, several experiments were compared such as to directly polymerize a membrane without any backstop, to polymerize with polytetrafluoroethylene(PTFE) or nylon membrane as backstop. The imprinted composite membrane with nylon(Nylon-ICM)had the advantages of uniform surface,better flux, better tenacity and high selectivity property. The good result using Nylon-ICM to separate CN and CD provided an experiment foundation to further investigate imprinted composite membrane.4 Molecular imprinted polymer against Epigallocatechin gallete(EGCG) was prepared and its molecular recognition characteristics to EGCG were evaluated by batch adsorption experiments. At the same time, the EGCG-imprinted polymer was applied to extract EGCG from tea polyphenols(TP) which had been extracted from green tea. Firstly, the presence of hydrogen bond between template and monomer was proved by the change of UV spectrum. Secondly, the special ablity to recognize and bind EGCG was showed by the MIP's adsorption experiments to EGCG, GCG, EGC and ECG. And the separation factor could be 2.54 between EGCG and GCG The EGCG-imprinted polymer exhibited higher selectivity and better recognition ability to EGCG compared to the non-imprinted polymer(NIP). In addition, the EGCG-MIP had been used as solid-phase in a column to extract EGCG from TP. The extraction conditions, such as cleaning agent, eluent, uploading quantity, recovery rate, using times, were tested and choosed. The better condition to the column was as following: 7.46mg EGCG per gram to upload, then methanol-water(l '. 9, v/v) solution to clean the column, methanol-acetic acid (9 * 1, v/v) to elute EGCG from the column. The EGCG recovery rate was 69.3%, and the ablity to recognize didn't descend when the EGCG-MIP column used 20 times. It's significative to apply the MIP as solid phase materials to extract effective components from plant extracts according to the MIP's special ability to recognize the objective molecular.5 Resveratrol imprinted polymer was prepared by molecular imprinting technique, and the MIP was try to use as solid-phase material to separate resveratrol from Polygonum cuspidatum Sieb. et Zucc.extracts. The interactional strength between template and monomer was expressed by infrared spectra. The molecular imprinted polymer was investigated in equilibrium binding experiments to evaluate the molecular recognition and binding characteristics of the Res-MIP.Scatchard analysis showed that two sites were produced in the polymer matrix and their dissociation constants were calculated to be 2.665 X 10 "3mol/L, 7.998 X 10"4 mol/L respectively. The results showed that, compared with non-imprinted polymer(NIP), the imprinted polymer exhibited much higher affinity for trans-resveratrol among the tested compounds: Res, Pol and BPA. Also, the MIP was applied to separate resveratrol from Polygonum cuspidatum Sieb. et Zucc. Extracts. The purity of the Res' HPLC Peak was 85.7% and 74.0% recovery rate was obtained.The study on this paper can provide an experiment foundation to further investigate molecular imprinting technology on molecular recognition, membrane separation and solid-phase extraction.