光聚合整体式咖啡因印迹毛细管柱的制备及分离性能

A novel and simple method for the \%in situ\% preparation of monolithic molecularly imprinted flow\|through polymers is described. The polymers were prepared inside UV transparent fused silica capillaries by photo\|initiated polymerization of a mixture of caffeine as the template, methacrylic acid as the functional monomer , trimethylolpropane trimethacrylate as the cross\|linking agent in the presence of a porogenic solvent consisting of toluene and isooctane . Scanning electron micrographs confirmed the presence of the clusters of globules separated by large pores on the monolithic structure. The effectiveness of the imprinted polymer monolithic column was demonstrated in microcolumn liquid chromatography(\%μ\%\|HPLC)mode by the screening of caffeine from a mixture of four structural analogues, the resolution factor \%R\%\-s of 2.57 and 2.97 for the separation of caffeine against theophylline and theobromine, respectively, were obtained, while the non\|imprinted column showed no specific selectivity. It is considered that the template was effectively imprinted in monolithic polymer by photoinitiated \%in situ\% polymerization at a low temperature. Several factors such as the molar ratio of the functional monomer to the imprint molecule and polymerization time affecting the flow\|through properties of a MIP column were also investigated. The results show that the obtained columns exhibit higher resolution and column efficiency against the structural analogues than do columns packed with MIP prepared by bulk polymerization and columns packed with continuous molecularly imprinted polymer rod prepared by \%in stiu\% method.