Determination of gold by electrothermal atomic absorption spectrometry after electrodeposition on a graphite tube

The inner wall of a graphite tube served as the surface for the adsorptive accumulation and for the electrodeposition of gold from a solution. A flow-through cell was constructed. After the deposition step, the graphite tube was placed into the graphite furnace and an atomization program was applied. To reach the best results, the electrodeposition conditions, such as the medium, deposition potential or current and the flow rate of solution, were optimized. As the working electrodes, pyrolytic graphite coated tubes, uncoated electrographite tubes and tubes covered by elemental palladium were used. This palladium surface was obtained by electrodeposition of palladium prior to gold deposition. For this surface and 3 ml of solution, the sensitivity of determination was 50 times higher than that of the direct sampling of 20 μl solution into a pyrolytic graphite coated tube. The procedure was applied to the determination of gold in river waters.