POTENTIOSTATIC AND GALVANOSTATIC MODULATION OF LIQUID-CHROMATOGRAPHY

Simplified versions of the chromatographic column in electrochemically modulated liquid chromatography were possible. A two electrodes desig n had a good response to changes in potential, yet excluding the need for an external reference electrode, supporting electrolyte, and porou s stainless steel. The cell constants for both the two and three elect rodes designs were similar. The incorporation of the reference electro de into the PVC joint of the column body resulted in fast potential eq uilibration times, where about a 50% decrease in the cell constant was observed using this new modification Both the two- and the new three- electrode designs resulted in self contained, rigid, and reliable col umns that can be safely dry stored; no porous stainless steel was a ne cessary material for the counter electrode. Galvanostatic, rather than potentiostatic, modulation of separations was successful. Interesting ly, both the two and three electrode designs resulted in identical chr omatograms when the same current was used. These results suggest that the simple two electrode design with regular, rather than porous, stai nless steel as the counter electrode has the same performance as that of the three electrode design, which requires an external reference el ectrode, external supporting electrolyte, as well as a porous stainles s steel counter electrode.