硫醇-烯点击化学法制备C18毛细管电色谱开管柱及其性能研究

摘要

A novel C18 open-tubular column (C18 capillary) for capillary electrochromatography was prepared based on thiol-ene click chemistry between n-octadecanethiol and vinyl-functionalized capillary ( Vinyl capillary ). The inner wall of capillary was chemically modified with vinyltrimethoxysilane to provide ene-functionality. Then n-octadecanethiol was chemically bonded on surface of Vinyl capillary via thiol-ene click chemistry. The surface features of the prepared C18 capillary were determined using scanning electron microscopy. The effects of buffer pH on the electroosmotic flow (EOF) of C18 capillary, Vinyl capillary and bare capillary were investigated. The experiment results indicated that the lowest EOF profile was obtained on the C18 capillary under the same experimental conditions compared to Vinyl capillary and bare capillary. To evaluate the column performance, test mixture of three polycyclic aromatic hydrocarbons ( PAHs ) was electrochromatographic separation on the C18 capillary, Vinyl capillary and bare capillary. The electrochromatographic retention behavior of the selected model PAHs on C18 capillary was also investigated. The experiment results showed that C18 capillary exhibited typical reversed phase electrochromatographic behavior toward PAHs. Compared with Vinyl capillary, the relatively good peak shape and no peak tailing were observed for the separation of basic model analytes on C18 capillary, which may be attributed to embedded polar sulphur groups on the surface of the C18 capillary that effectively shielded the adsorption of basic analytes onto the residual silanol groups.%基于十八烷基硫醇与乙烯基功能化毛细管(Vinyl capillary)的硫醇-烯点击化学反应,制备了一种新型的C18毛细管电色谱开管柱(C18capillary).采用乙烯基三甲氧基硅烷对毛细管内壁进行乙烯基功能化,然后通过硫醇-烯点击化学反应共价键合十八烷基硫醇于Vinyl capillary内表面.采用环境扫描电镜对C18 capillary进行了形貌表征.考察了缓冲溶液pH值对C18 capillary、Vinyl capillary和裸毛细管柱(Bare capillary)电渗流的影响.结果表明；在相同实验条件下,C18capillary的电渗流最小.以3种多环芳烃为模型化合物,评价了C18capillary的电色谱柱性能；同时考察了模型化合物在C18capillary上的电色谱保留行为.实验表明,其保留机理是基于典型的反相作用.当C18 capillary用于碱性模型化合物分离时,碱性物质在C18 capillary上的峰形较好,无明显的峰拖尾现象,这可能是由于C18capillary表面含有极性的S基团能够屏蔽残留硅羟基对碱性化合物的吸附作用.