The use of a bivalent counter anion to control the effective mobility of the hydrogen ion constituent in cationic isotachophoresis

The use of a bivalent counter anion for cationic isotachophoresis was studied both theoretically and experimentally. A mathematical model was proposed and solved to give the effective mobility of the hydrogen ion constituent, u H.H , in the respective electrolyte systems. The theoretical values agreed well with the experimental data in a series of electrolyte systems. The dependence of u H.H on such parameters as pH of the leading electrolyte, ionic mobilities of leading and counter ions, and dissociation constants was calculated and discussed. A bivalent counter anion will prove useful for the separation of low mobility cations and weak bases, as shown for the separation of substituted anilines in a succinate electrolyte system.