ELECTRICALLY DRIVEN CAPILLARY LIQUID-CHROMATOGRAPHY AT AMBIENT-PRESSURE

The applicability of electrochromatography at ambient pressure is demo nstrated on capillaries packed with 3-mu m reversed phase particles. T he efficiency of the columns is good; reduced plate heights close to 2 were found. The effects of the buffer concentration on the plate heig ht, the electroosmotic flow, and the current were investigated. The pl ate height appears to increase with decreasing buffer concentration. F rom this behaviour and from the relative large obstruction factors fou nd, it can be concluded that considerable flow arises through the inte rconnected pores of the particles under electro drive. The performance under pressure and electrically driven conditions was compared, which revealed that with capillary electrochromatography (CEC) two times mo re plates can be generated than with pressure drive in the same time. The applicability of CEC for ion pair systems is demonstrated with the separation of nucleobases and nucleosides using sodium dodecyl sulfat e as surfactant. (C) 1998 John Wiley & Sons, Inc.