Pressurized flow-driven capillary electrochromatography using ion exchange resins

Capillary electrochromatography using cation and anion exchange resins under pressurized flow is demonstrated to be applied to the separation of charged solutes, such a lanthanide ions. The typical variation of elution order for the mixture of sulfite, sulfate, and thiosulfate ions, the reduction and extension of elution times due to the application of high voltage, and the simultaneous separation of cations and anions are demonstrated. A minor component appears by shifting the elution time of a major component while applying a high electric field. The electric resistance of the column was measured under electrochromatographic conditions, and its dependence on the applied voltage has been discovered. From the relationship between elution times and applied voltage, the sum of electrophoretic mobility of an ion and electroosmotic mobility is estimated for landthanide cations. The capacity factor in electrochromatography is found to depend, to some extent, on the potential gradient.