毛细管电色谱中双电层叠加的研究

通过流动相中电解质浓度对毛细管电色谱柱效能的流动相平均线速度的影响，研究了ＣＥＣ中双电层叠加现象。提出选择合适电解质组成的浓度及在制备色谱柱过程中避免细小和破碎的固定相颗粒进入柱中，以有效地减小双电层叠加作用。

Effect of Double Layer Overlap on the Column Performance and Electroosmotic Velocity in Packed Capillary Electrochromatography

The effect of double layer overlap on the performance and electroosmotic velocity in the packed capillary electrochromatography (CEC) was studied. The theory analysis on the double layer overlap in the packed CEC was described. Some experiments on the influence of electrolyte concentrations in eluent on the performance and the electroosmotic velocity were carried out to elucidate the phenomenon of double layer overlap in the packed CEC. The results showed that the packing structure and the homogeneity of the packed bed were the internal factor that resulted in the emergence of the double layer overlap in the packed CEC. Once the double layer overlap was formed in the packed CEC the electroosmotic velocity and effective field strength decreased, which deteriorated the performance. The composition and concentration of electrolyte in eluent were the external factor that influenced the electroosmotic velocity and separation efficiency while the double layer overlap was existed in the packed CEC. Thus, two approaches could minimize the effect of double layer overlap to achieve higher performance in pecked CEC. One is to take precautions against crushing particles in preparation of a packed capillary column. The other is to use judicially selected electrolyte composition as well as concentration.