Ion exchange ability of N-octylpyridinium hexafluorophosphate in carbon ionic liquid electrode for efficient adsorptive preconcentration and selective determination of ultratrace gold chlorocomplexes

A new application of a carbon ionic liquid electrode (CILE) has been explored for preconcentration and quantification of trace amount of Au(III) chlorocomplexes. The procedure is based on the accumulation of tetrachloroaurate complexes at the electrode surface under an open circuit potential condition followed by cyclic voltammetry (CV) and differential pulse cathodic stripping voltammetry (DPCSV). An ion exchange mechanism has been proposed for efficient and fast accumulation of Au(III) chlorocomplexes. Effects of different experimental parameters such as electrolyte concentration, pH, and preconcentration time on the voltammetric signals were investigated. It was found that under the optimized experimental conditions, the linear range of measurement and the detection limit were 5.00 x 10(-9)-2.25 x 10(-6) and 0.80 x 10(-9) mol L-1, respectively. Possible interference from coexisting ions was also studied. The procedure was applied for determination of gold in water and human blood serum samples, and acceptable accuracy was achieved.