[Deductive inference on the plate height equation of electrochromatography]

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: [formula: see text] 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.