Preparation of molecularly imprinted polymers via non-covalent imprinting method and their application for chromatography

• Main Authors: Yu-Chi Lin, 林鈺淇
• Other Authors: Wen-Chien Lee
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/57801330287705559497

碩士 === 國立中正大學 === 化學工程研究所 === 91 === Abstract Molecular imprinting techniques can offer complementary binding sites on the matrix for the template molecule. Recently, the molecularly imprinted polymers (MIPs) have widely used as the chromatographic support for the separation of target molecule. First, this study focuses on the effect of solvent polarity on the polymerization of MIPs and their applications in liquid chromatography. Second, ethylene glycol dimethacrylate were copolymerized with either methacrylic acid or 4-vinylpyridine in the non-polar solvent like chloroform and THF for the printing of N-protected amino acid as the template molecule. The resultant imprinted polymers were used for the chromatographic resolution of Boc-tyrosine and Boc-phenylalanine, which are different from each other with an aromatic hydroxyl group on the side chain. The interaction between functional groups on the printed polymer and dipeptide or N-protected amino acid, and the influence of mobile phase on chromatographic efficiency were studied. The molecularly imprinted polymers were prepared by the non-covalent imprinting method through the bulk polymerization of a complex forming by template, functional monomer, and a cross-linker. The bulk polymerization was carried out in chloroform with 2,2’-azobisisobutyonitrile as the initiator using a UV-initiation at 4℃. These MIPs were then ground and sieved to yield particles with the sizes ranging from 25 to 44μm. After removal of template molecules, columns packed with MIP particles were employed for the chromatography of different samples like amino acids, pure amino acids and dipeptides. The polymer synthesized polar solvent was found to have different morphology compared with that polymerized in non-polar solvent and cannot interact to the molecules in the chromatographic samples. To the contrast, the imprinted polymers prepared in the non-polar solvent possessed recognition sites for rebinding of template. The polymer obtained from copolymerization of methacrylic acid and ethylene glycol dimethacrylate for the imprinting of Boc-Ala could interact to amino acids and dipeptides, but the separation was bad by chromatography. By the non-covalent method, 4-vinylpyridine and ethylene glycol dimethacrylate were copolymerized for the imprinting of Boc-Tyr. The column packed with the Boc-Tyr-imprinted polymer particles could be effectively operated for the chromatographic separation of Boc-Phe and Boc-Tyr using the mobile phase containing 0.5% to 1% volume of acetic acid in acetonitrile. A separation factor of 2.02 was achieved. Results suggest that solutes in the sample having a similar structure could be well separated based on the number and strength of the interactions between solute molecules and functional groups on the molecularly imprinted polymer.