Voltage-Induced Sample Release from Anion Exchange Supports in Capillary Electrochromatography.

‐7 is one of the topics in the separation sciences as it plays a crucial role in the stages developing nowadays. In this method, an electric field is applied along a capillary column, and the electric field introduces two new factors, electroosmotic flow and electrophoretic migration of solutes. These two factors do not exist in ordinary liquid chromatography. These two new factors influence the behavior of solutes in the mobile phase. Namely, both factors contribute to the apparent flow velocities of solutes. During an experiment 7,8 of electrochromatography using ion exchange supports, an interesting phenomenon was observed. When an electric field was applied on the column, the baseline of the chromatogram fluctuated, and after a while it assumed its original position. 8,9 Namely, the applied voltage causes a temporary increase in the solute concentration indicated by a peak without any sample injection. Here, the electric field probably induces the variation of the distribution coefficient. Therefore, the electric field has an effect not only on separations due to the electrophoretic mobility in mobile phase, but also on the equilibrium between solutes and packing supports. It is necessary to understand this phenomenon for the further development of electrochromatography. And this phenomenon gives new information about the interaction between solute and ion exchange supports. In the present report, the chromatographic behaviors of a mixture of two compounds were examined by using a tiny mini-column (we called this mini-column as mini-bed) under a continuous sample introduction with and without applied voltage. For detecting the variation of the two compounds a multi-scanning detector was used. Based on this phenomenon, a theory is now being proposed.