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.