1μm硅胶颗粒固定相的加压电色谱分离性能

制备了1μm无孔硅胶颗粒。通过电动填充法得到总长度为45cm(固定相填充长度为20cm)、内径为100μm的毛细管色谱柱。以乙腈-水体系作为流动相,详细考察了碱性化合物在该色谱柱上的加压电色谱(pCEC)分离性能,讨论了流动相比例、缓冲液浓度、pH值及操作电压等因素对分离的影响。实验结果表明,裸硅胶柱在乙腈-水体系分离碱性样品中表现出典型的反相色谱分离性能;缓冲液浓度的改变则对分离影响不大。当pH值改变时,碱性化合物的解离程度发生变化,它们与固定相之间的作用力发生变化,使得分离度发生相应的变化。分离柱效随施加电压的增加而增加,在1kV电压下,裸硅胶柱对邻甲苯胺的柱效为35000理论塔板/m。

Separation performance of 1-μm silica particles as stationary phase for pressurized electrochromatography

Bare nonporous silica particles with diameter around 1 μm were prepared.A 20 cm section of a total length of 45 cm capillary (100 μm i.d.) was packed electrokinetically and the separation performance of basic compounds was investigated in the pressurized capillary electrochromatography (pCEC) system using 1 μm nonporous bare silica spheres as stationary phase and acetonitrile-water as mobile phase.The effects of the composition of the mobile phase,the concentration of the buffer,pH value,applied voltage and so on on the separation performance were investigated.The experimental results demonstrated that the bare silica column showed a typical reversed phase separation mechanism when it was used for separation of basic compounds.The separation performance changed slightly with changing buffer concentration.Since the degree of dissociation of the basic compounds depended greatly on the pH value,the interaction between the compounds and stationary phase changed with the changing of pH value,thereby changing the resolution of the compounds.The separation performance increased with the increase of applied voltage.A column efficiency of 35 000 for o-toluidine was obtained when a voltage of 1 kV was applied.