EVALUATION OF THE PARAMETERS DETERMINING THE PERFORMANCE OF ELECTROCHROMATOGRAPHY IN PACKED CAPILLARY COLUMNS

Electrochromatography is a variant of reversed-phase liquid chromatography performed in capillary columns whereby transport of the eluent is accomplished by applying an electric field across the length of the column. Column-length restrictions arising from resistance to flow encountered with conventional pumping are absent in electrochromatography, allowing separation in capillaries packed with 1.5-mu m stationary phases up to 50 cm, thus rendering efficiencies of more than 100 000 plates per column. Practical problems, however, have restricted the number of successful applications reported. A number of parameters determining the electrochromatographic performance are investigated: eluent, frits, packed columns and optional supplementary pressure. These factors are investigated separately and then combined stepwise. With thoroughly degassed eluent, frits made of sintered silica gel, and the use of supplementary pressure, stable and reproducible conditions may be readily obtained.