EFFECTS OF ELECTROLYTES ON MANIPULATION OF THE STATIONARY-PHASE IN ELECTROCHEMICALLY MODULATED LIQUID-CHROMATOGRAPHY

Electrolytes were found to have an important influence on the cell con stant in electrochemically modulated liquid chromatography. The depend ence of cell constant on electrolyte type did not reflect any relation with regard to electrolyte conductivity values. However, electrolytic species of larger ionic sizes result in significantly lower cell cons tants, and vice versa. It was also found that the cell constant is exp onentially dependent on electrolyte concentration, with higher electro lyte concentrations resulting in decreased cell constants. When a pote ntial ramp is applied to the working electrode, a steep change in the potential of the working electrode towards the final potential takes p lace directly after the application of the potential ramp. The change in the potential of the working electrode then follows an exponential decay isotherm, which depends on both electrolyte type and concentrati on.