Determination of chloride complex of Au(III) by capillary zone electrophoresis with direct UV detection

Capillary zone electrophoresis was used for the determination of gold(III) chloride using direct UV detection at 220 nm. By using a capillary column 70 cm long, the optimum applied voltage was found to be around -7 kV; carrier solution containing 0.1 M HCl and 0.4 M NaCl was used as an additive. At this pH, the electroosmotic flow-rate appears to be almost zero. The effects of chloride concentration and the applied voltage on determination efficiency are discussed. Heat generation appeared negligible as the electric current and migration time were reproducible. The analytical performance is discussed in terms of the detection limit, linearity and reproducibility. A single trial was performed in 18 min. Under these conditions, Pd(II) and Pt(IV) can also be determined; the order of mobility in the electropherogram was as follows: PdCl42- > PtCl62- > AuCl4-. The method was applied to the monitoring of Au concentration during a study of AuCl4- transport through solid-supported liquid membranes.