Graphene oxide/NiO nanocomposite-modified carbon paste electrode for the simultaneous detection of carmoisine and tartrazine as two azo dyes in food samples

A carbon paste electrode (CPE) was modified with a graphene oxide (GO)/NiO nanocomposite (GO/NiO/CPE) and used as the working electrode for the voltammetric analysis of carmoisine. In the oxidation of carmoisine, the GO/NiO/CPE showed increased electrocatalytic activity. With a detection limit of 0.1 μM under ideal conditions, the oxidation peak currents of carmoisine were linearly proportional to its concentration over the range 0.3 to 500.0 μM. Additionally, the GO/NiO/CPE showed good efficacy in detecting carmoisine even in the presence of tartrazine, suggesting that both chemicals might be determined simultaneously. The GO/NiO/CPE was appropriate for the simultaneous detection of carmoisine and tartrazine using differential pulse voltammetry because the oxidation peak potentials of the two azo dyes were adequately separated by 420 mV.