电色谱塔板高度方程的推导

Deductive Inference on the Plate Height Equation of Electrochromatography

比较了电色谱与高效液相色谱在动力学过程方面的异同。从热传导方程出发导出在有源无限长均匀圆柱体内温度场分布函数及组分移动速度径向分布函数，进而导出了温度场导致谱带弥散的弥散系数Ｄ热。提出了较全面地反映电色谱动力学过程的塔板高度方程，从而为改进柱型、选择电色谱分离条件提供了理论参考。

In this paper, the dynamic process of electrochromatography has been studied. The differences between electrochromatography and high performance liquid chromatography have been compared. The author considers that because of the effects of electroendosmosis flow at the surface and interior of stationary phase particles, the plate height increment due to axial dispersion of the eluite in the interstitial space and the intraparticular diffusion resistance to mass transfer will reduce, and the “film” resistance at the particle boundery will disappear. But when a current passes along the electrochromatographic column Ohmic heat releases and the tube will be heated up. The temperature difference between the center of tube and the tube wall will affect the plate height. The plate height contribution from this is quite significant and can seriously reduce the efficiency of column. Thus, a general plate height equation has been derived to express the effect of axial dispersion in the electrochromatographic process, mass transfer resistances at the mobile phase, kinetic resistances associated with the reversible binding of eluite by the stationary phase and the temperature distribution effect. According to these theories, the plate height equation of electrochromatography has been obtained as following:H=2γD m u+2λd p 1/3 u 1/3 +ω(D m /d p ) 1/3 +2k′u(1+k′) 2k d +θ′k′ 2d 2 p uD m (1+k′) 2+u(6B 0+B 2r 2 0)r 2 024D m exp ( Kαr 2 0+a)It is suggested that there exist a lot of factors which influence the column efficiency of electrochromatography, such as axial dispersion in the interstitial space, mass transfer resistances at the mobile phase, kinetic resistances with the reversible binding of eluite by the stationary phase, and the temperature field in the column inside. The influence of temperature field is closely related with internal diameter of column.