Lin Jian, Huang Guihua, Lin Xucong, Xie Zenghong
Department of Chemistry, Fuzhou University, Fuzhou, PR China.
Electrophoresis. 2008 Oct;29(19):4055-65. doi: 10.1002/elps.200800084.
A novel porous polymethacrylate-based monolithic column by in situ copolymerization of 3-sulfopropyl methacrylate (SPMA) and pentaerythritol triacrylate in a binary porogenic solvent consisting of cyclohexanol/ethylene glycol was prepared. The monolith possessed in their structures bonded sulfonate groups and hydroxyl groups and was evaluated as a hydrophilic interaction and strong cation-exchange stationary phases in capillary liquid chromatography (cLC) and pressure-assisted CEC using small polar neutral and charged solutes. While the SPMA was introduced as multifunctional monomer, the pentaerythritol triacrylate was used to replace ethylene glycol dimethacrylate as cross-linker with much more hydrophilicity due to a hydroxyl sub-layer. The different characterization of monolithic stationary phases were specially designed and easily prepared by altering the amount of SPMA in the polymerization solution as well as the composition of the porogenic solvent for cLC and pressure-assisted CEC. The resulting monolith showed the different trends about the effect of the permeabilities on efficiency in the pressure-assisted CEC and cLC modes. A typical hydrophilic interaction chromatography mechanism was observed at higher organic solvent content (ACN%>70%) for polar neutral analytes. For polar charged analytes, both hydrophilic interaction and electrostatic interaction contributed to their retention. Therefore, for charged analytes, selectivity can be readily manipulated by changing the composition of the mobile phase (e.g., pH, ionic strength and organic modifier). With the optimized monolithic column, high plate counts reaching greater than 170 000 plates/m for pressure-assisted CEC and 105 000 plates/m for cLC were easily obtained, respectively.
通过在由环己醇/乙二醇组成的二元致孔溶剂中原位共聚甲基丙烯酸3 - 磺丙酯（SPMA）和季戊四醇三丙烯酸酯，制备了一种新型的基于多孔聚甲基丙烯酸酯的整体柱。该整体柱结构中含有键合的磺酸根基团和羟基，在毛细管液相色谱（cLC）和压力辅助毛细管电色谱（CEC）中，使用小极性中性和带电溶质，被评估为亲水相互作用和强阳离子交换固定相。当引入SPMA作为多功能单体时，季戊四醇三丙烯酸酯被用来替代乙二醇二甲基丙烯酸酯作为交联剂，由于羟基亚层，其亲水性更强。通过改变聚合溶液中SPMA的量以及用于cLC和压力辅助CEC的致孔溶剂的组成，特别设计并易于制备整体固定相的不同表征。所得整体柱在压力辅助CEC和cLC模式下，渗透率对柱效的影响呈现出不同趋势。对于极性中性分析物，在较高有机溶剂含量（ACN%>70%）时观察到典型的亲水相互作用色谱机制。对于极性带电分析物，亲水相互作用和静电相互作用都对其保留有贡献。因此，对于带电分析物，可以通过改变流动相的组成（例如pH、离子强度和有机改性剂）轻松控制选择性。使用优化后的整体柱，分别轻松获得了压力辅助CEC下大于170000塔板数/米和cLC下105000塔板数/米的高柱效。
