茶碱晶体印迹聚合物

采用分子印迹的方法 ,以甲基丙烯酸为功能单体 ,双甲基丙烯酸乙二酯为交联剂 ,茶碱晶体为印迹物 ,采用光引发聚合的方式 ,制备了茶碱晶体印迹聚合物 .扫描电镜观察显示 ,聚合物表面用 0 1mol L盐酸溶液反复洗涤除去茶碱晶体后 ,可以在饱和茶碱溶液中诱导茶碱结晶的生成 ;而在同样条件下的咖啡因晶体印迹聚合物表面则没有相应的诱导结晶能力 .分析结果表明 ,茶碱和咖啡因在咪唑取代基上的微小差异可能是导致两者表现不同的主要原因 ,茶碱分子可以通过其咪唑环和相邻嘧啶环上的羰基以氢键或静电作用的方式与甲基丙烯酸的羧基产生分子识别所需的 3点协同相互作用 ,而结构相似的咖啡因则因其咪唑环上的取代基不同 ,无法满足识别所需的基本要求

PREPARATION AND CHARACTERIZATION OF THEOPHYLLINE CRYSTAL-IMPRINTED POLYMERS

Theophylline crystal imprinted polymers capable of inducing theophylline crystallization in aqueous media were prepared by a photo-initiating approach with methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EDMA) as the cross-linker.SEM studies showed that the surface of the theophylline-imprinted polymer,after a thoroughly washing procedure with 0.1 mol/L HCl solutions,could well induce theophylline crystallization process,when it was immersed in a saturated theophylline solution for 24 h.On the contrary,the caffeine-imprinted polymer failed to show the same result under the given conditions.The subtle distinction in their molecular structures related to the imidazole ring might be one of the major reasons responsible to the observed results.The theophylline molecule could interact with the carboxyl of methacrylic acid via its imidazole ring as well as the neighboring carbonyl group in its pyrimidine part by hydrogen bonding and/or electrostatic interactions,while the caffeine molecule could not form the same bonds with the methacrylic acid due to the existence of its methyl displaced imidazole ring.