Electrically polarized ion-exchange beds in ion chromatography:  eluent generation and recycling

This paper describes how electrically polarized ion-exchange beds pumped with water can produce electrolyte of steady and controllable concentration. Such devices make it possible to use water as the pumped phase in ion chromatography (IC), thus avoiding off-line eluent preparation. Control of the electrical current flowing through the devices allows precise control of the concentration of eluent that they deliver. This provides a new way of performing gradient and isocratic elutions. Using water as the carrier and two small beds of resin, one as a generator the other as a suppressor, and periodically reversing their roles through automatically switched valves, we have developed a form of continuous IC that involves little intervention by the user. The paper presents the principles of the new method and examples of its use in anion analysis.