硅胶电色谱分离机理的研究

Study on the Separation Mechanisms in Capillary Electrochromatograpy with Bare Silica-packed Column

对硅胶电色谱柱的性能进行了考察,发现在水/有机溶剂流动相条件下,几乎不存在气泡问题,流动相的组成在有机溶剂浓度、电解质浓度、pH等方面可以在较大范围变化.选用5种典型样品,对硅胶电色谱的分离机理进行系统研究,发现有反相分配机理、正相吸附机理、离子交换机理以及电泳机理参与作用.同时考察了有机溶剂浓度、电解质浓度、pH值等对分离的影响.此外,还首次提出了一种全新的电色谱模式-动态改性硅胶电色谱.

The separation mechanisms in capillary electiochromatography (CEC) of bare silica - packed column was investigated under aqueous - organic mobile phases. The separations of five typical solutes, including apolar compound (benzene) , polar compounds (formamide and dimethyl formamide) and basic compounds (pyridine and quinoline) , showed that reverse phase retention, normal phase retention, ion-exchange and electrophoresis mechanisms were involved. The effect of the concentration of organic modifier, the concentration of buffer and the pH value on separation were investigated. Due to the hydrophilicity of bare silica, the silica-packed column exhibits the following merit, i.e., the mobile phase composition can change in rather large range of organic modifier content, buffer concentration and pH value. This means that the bubble problem that are usually met in ODS-packed column can be minimized with the silica-packed column. Additionally, we presented a novel model of CEC, termed as dynamically modified silica column CEC. Five alkyl substitued benzenes were baseline separated with a mobile phase containing cetyltrirnethylammonium bromide.