Determination of gold by anodic stripping voltammetry with carbon fiber ultramicroelectrodes

Carbon fiber ultramicroelectrodes have been used in anodic stripping voltammetry (ASV) of trace gold. The advantageous characteristics of ultramicroelectrodes combined with ASV resulted in a fast, selective, sensitive and reproducible method. An electrochemical pretreatment was necessary for analytical determinations. The combination of supporting electrolyte (HCl 0.1 M) and electrodeposition potential (0.0 V) gave a high selectivity. A calibration plot from 1.00 x 10(-8) M to 1.60 x 10(-6) M (r = 0.9994) was achieved with a detection limit of 5.94 x 10(-9) M and a relative standard deviation (RSD) of 2.87 % at 3.0 x 10(-7) M. Ag-I, Cu-II, Pb-II and Hg-II metals in the concentration of 1.00 x 10(-6) M were nor found to interfere with the ASV of gold (3.00 x 10(-7) M) when carried out under optimum conditions. The procedure was applied to the determination of gold in two tap water synthetic samples.