EXPERIENCES WITH PACKED CAPILLARY ELECTROCHROMATOGRAPHY AT AMBIENT-PRESSURE

The practical execution of packed capillary electrochromatography is e valuated. The most serious problem is the generation of air bubbles in the system. This occurs especially in frits which were fabricated by glueing particles differing from the packing particles. No air bubbles were generated with frits which were prepared by locally sintering a narrow band of the reversed-phase packing by means of a heating filame nt, while flushing the column with water. In this way electrochromatog raphy can be performed simply without pressurizing the buffer vials, p roviding the mobile phase is frequently degassed with helium. The perf ormance under electrically driven conditions appears to be excellent a nd for 5 mu m reversed-phase particles reduced plate heights down to 1 .8 were achieved. Compared to pressure driven conditions, 25-40% small er plate heights were obtained under electrically driven conditions.