Anodic and cathodic stripping voltammetric determination of gold using graphene modified glassy carbon electrode

In this study, a graphene based electrode material was developed for the electrochemical analysis of gold which has prominent commercial importance. It was seen via cyclic voltammetry method that glassy carbon electrode modified with graphene material, whose preparation and characterization had been studied extensively, was sensitive to Au (III). Anodic and cathodic responses measured due to Au (III) ions were amplified by pre-deposition process, and after determining the optimum conditions for deposition it was seen that the anodic response?s sensitivity in proportion to the cathodic one was 2 to 12 times higher. Gold detection sensitivity via anodic differential pulse stripping method was found to be 66 times higher with respect to anodic stripping voltammetry. Interference effects of some ions over anodic peaks of Au (III) in positive and negative directions were determined by anodic stripping voltammetry method. Rhodamine-B and naphthylamine added in graphene as complexing agents to increase presaturation during cathodic stripping had increased sensitivity only few fold. After the sensitivity studies, due to the higher sensitivity of differential pulse anodic stripping method validation of the corresponding method was done. For the differential pulse anodic stripping voltammetry, two linear working ranges of 0,18 - 0,80 µM and 0,80 - 7,2 µM were specified. For the first and second working ranges, LOD values of 0,05 and 0,014 µM, and LOQ values of 0,18 and 0,80 µM were found, respectively. Under these determined conditions, the reliability, repeatability and precision of the applied method are quite high.