Fu Hongjing, Xie Chuanhui, Xiao Hua, Dong Jing, Hu Jiwei, Zou Hanfa
National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116011, China.
J Chromatogr A. 2004 Jul 30;1044(1-2):237-44. doi: 10.1016/j.chroma.2004.04.076.
A capillary electrochromatography (CEC) monolithic column with mixed modes of reversed-phase and anion-exchange stationary phases was prepared by in situ polymerization of 2-(methacryloxy)ethyltrimethylammonium methyl sulfate (MEAMS) and ethylene dimethacrylate (EDMA) in a binary porogenic solvent consisting 1-propanol and 1,4-butanediol. The ammonium groups on the surface of the stationary phase generate an electroosmotic flow (EOF) from cathode to anode, and serve as a strong anion-exchange stationary phase at the same time. The EOF of the stationary phase can be determined by the amount of MEAMS monomer in reaction mixtures during the polymerization. The monolithic stationary phases exhibited reversed-phase chromatographic behavior toward neutral solutes. For charged solutes, hydrophobic as well as electrostatic interaction/repulsion with the monoliths was observed. Separations of aromatic compounds and basic compounds on the prepared column were performed under the mode of CEC. Peak tailing of basic compounds was avoided and the efficient separation of aromatic acids was achieved using neutral mobile phase due to the same direction of EOF and electrophorestic mobility of negatively charged solutes.
通过在由1-丙醇和1,4-丁二醇组成的二元致孔溶剂中原位聚合2-(甲基丙烯酰氧基)乙基三甲基硫酸甲酯（MEAMS）和二甲基丙烯酸乙烯酯（EDMA），制备了一种具有反相和阴离子交换固定相混合模式的毛细管电色谱（CEC）整体柱。固定相表面的铵基团产生从阴极到阳极的电渗流（EOF），同时作为强阴离子交换固定相。固定相的EOF可以通过聚合过程中反应混合物中MEAMS单体的量来确定。整体固定相对中性溶质表现出反相色谱行为。对于带电溶质，观察到与整体柱的疏水以及静电相互作用/排斥。在CEC模式下对制备的柱上的芳香族化合物和碱性化合物进行了分离。由于EOF与带负电溶质的电泳迁移率方向相同，使用中性流动相避免了碱性化合物的峰拖尾，并实现了芳香酸的高效分离。
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