When a potential is applied across the two electrodes, the water regenerant undergoes electrolysis, forming hydronium ions at the anode and hydroxide ions at the cathode. See the following figure.
- Dionex ADRS 600: Hydronium is transported from the anode towards the cathode and enters the sample chamber. At the same time, the matrix cations in the sample move towards the cathode and enter the cathode chamber. The matrix cations combine with the hydroxide ions at the cathode forming a base and are removed from the regenerant chamber. The net effect of this transport of ions is neutralization of the sample matrix ions to a weakly ionized form while the sample anions are typically converted to a strongly ionized form. The sample anions are now in a weakly dissociated matrix such as water and are ready for analysis.
- Dionex CDRS 600: Hydroxide is transported from the cathode towards the anion and enters the sample chamber. At the same time, the matrix anions in the sample move towards the anode and enter the anode chamber. The matrix anions combine with the hydronium ions at the anode forming an acid and are removed from the regenerant chamber. The net effect of this transport of ions is neutralization of the sample matrix ions to a weakly ionized form, while the sample cations are typically converted to a strongly ionized form. The sample cations are now in a weakly dissociated matrix such as water and are ready for analysis.