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

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.