Potentiostatic and Galvanostatic Modulation of Liquid Chromatography

Abstract

Simplified versions of the chromatographic column in electrochemically modulated liquid chromatography were possible. A two electrodes design had a good response to changes in potential, yet excluding the need for an external reference electrode, supporting electrolyte, and porous stainless steel. The cell constants for both the two and three electrodes designs were similar. The incorporation of the reference electrode into the PVC joint of the column body resulted in fast potential equilibration 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 columns that can be safely dry stored; no porous stainless steel was a necessary material for the counter electrode. Galvanostatic, rather than potentiostatic, modulation of separations was successful. Interestingly, both the two and three electrode designs resulted in identical chromatograms when the same current was used. These results suggest that the simple two electrode design with regular, rather than porous, stainless steel as the counter electrode has the same performance as that of the three electrode design, which requires an external reference electrode, external supporting electrolyte, as well as a porous stainless steel counter electrode.