Novel graphene modified carbon-paste electrode for promazine detection by square wave voltammetry

Graphene nanosheet prepared from graphite via a modified Hummers method was used to design a graphene-modified carbon-paste electrode (GCPE). The electrochemical behavior was investigated by studying the electrocatalytic behavior of the ferrocyanide redox couple on its surface by using cyclic voltammetry. The GCPE showed voltammetric responses with a higher level of sensitivity and a lower background current compared to the carbon paste electrode. The analytical applicability of the newly prepared electrodes was demonstrated by the powerful quantitative determination of promazine (PZ). The electrochemical behavior of promazine at the surface of the fabricated electrode was evaluated using cyclic voltammetry and square wave voltammetry. The voltammogram of promazine showed two oxidation peaks at 0.6 V and 0.9 V and one signal of a reduction peak at 0.57 V. A mechanism was proposed to explain the oxidation-reduction process of PZ. Square wave voltammetry (SWV) technique has been successfully applied in this study for the determination of PZ using the prepared graphene-based electrode. A linear dynamic range of 0.1 μM to 8 μM, regression factor (R²) of 0.9979, and a limit of detection (LOD) of 8 nM were obtained. The effective and straightforward method reported here to prepare the GCPE offers a high electrochemical activity and a relatively low background current. The GCPE has an excellent stability and can be recommended for promazine determination in various formulations.