咪唑侧基功能化聚离子液体修饰的混合模式色谱固定相的制备及其色谱性能

Preparation and chromatographic properties of mixed-mode chromatographic stationary phases modified by imidazole side-group functionalized poly(ionic liquids)

该文合成了咪唑侧基功能化的离子液体单体1-(4-乙烯基苄基)-3-氰甲基溴化咪唑盐,通过表面引发原子转移自由基聚合将该单体接枝到硅胶表面,制备了一种新型混合模式色谱固定相。采用红外光谱、元素分析及热重分析对其结构进行表征。该色谱固定相具有良好的分离能力。通过研究流动相pH对物质保留的影响,验证了物质在该固定相上存在反相-离子交换保留机理。通过与十八烷基硅烷键合硅胶固定相比较,证实了该聚离子液体固定相对物质保留提供了π-π作用。结果表明,对咪唑侧基功能化是制备新型离子液体固定相的可行方法。

A novel mixed-mode chromatographic stationary phase was prepared via surface initiated atom transfer radical polymerization using an imidazole side-group functionalized ionic liquid monomer, 1-(4-vinylbenzyl)-3-cyanomethyl bromide. The structure of the stationary phase was characterized by infrared spectroscopy, elemental analysis, and thermogravimetric analysis. The stationary phase showed good separation ability. The retention mechanism of reversed-phase/ion exchange toward solutes on the stationary phase was verified by determining the effect of mobile phase pH on the retention of substances. Compared with octadecylsilyl-bonded silica stationary phase, it is confirmed that the poly(ionic liquid)-modified stationary phase provides π-π interaction toward the retention of the solutes. The results show that the functionalization of imidazole side groups is a feasible method for preparing new ionic liquid stationary phases.