Electrophoretic Separation of Ions, Including Isotopic Ones, with Similar Chemical Properties for Preparative and Analytical Purposes

The reasons for the failure of the first attempts at countercurrent electrophoretic separation of isotopic lithium ions are analyzed. It is concluded that the separation of these ions in the potentiostatic version of the countercurrent process scheme used by the authors is futile. As an alternative for the preparative separation of isotopic and other ions with similar chemical properties, a galvanostatic mode of countercurrent electrophoretic separation is proposed. Using examples of the separation of alkali metal ions and isotopic lithium and rubidium ions, it is shown that in this case the system enters a stationary self-regulating regime and significantly higher separation factors are achieved compared to the potentiostatic version of the process. It has been determined that a high separation efficiency is achieved with a minimum length of the separation space. For significant effects of the separation of isotopic lithium ions, a separating column 4 mm in height filled with quartz sand is sufficient. Additionally, to address the analytical challenges of electrophoretic separation of isotopic ions of light elements, such as lithium and boron, the required efficiency is also achieved under the potentiostatic conditions of the traditional scheme of capillary zone electrophoresis, as demonstrated in the examples of determining the isotopic composition of the aforementioned elements.