The simultaneous separation of twenty-one metal cations using capillary isotachophoresis with on-column conductivity detection

Abstract

The possibility of using capillary isotachophoresis coupled with on-column conductivity detection for the separation of complex metal cation mixtures has been demonstrated. The simultaneous separation of a mixture of the 21 metal cations Ca²⁺, Mg²⁺, Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺, Be²⁺, La³⁺, Ce³⁺, Pr³⁺, Nd³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Cu²⁺, Y³⁺, Ho³⁺, Er³⁺, Tm³⁺, Yb³⁺ and Lu³⁺ has been reproducibly achieved using aqueous electrolytes. Calibration curves were produced for two of these ions, Co²⁺ and Er³⁺. A linear response was observed over the range from 0.02 mmol dm^–3 to 1.70 mmol dm^–3 for cobalt and 0.05 mmol dm^–3 to 1.00 mmol dm^–3 for erbium. These curves allowed limits of detection to be calculated as 0.015 mmol dm^–3 for cobalt and 0.045 mmol dm^–3 for erbium.