BACKGROUND Developing fast and reliable methods with little sample preparation has become increasingly important for process monitoring and control. Electrochemical methods stand out for their low cost and instrumental simplicity. Furthermore, electrodes with nanoparticles can improve the method's sensitivity and specificity. This study developed carbon paste electrodes modified with nanoparticles of copper and iron. In addition, cyclic voltammetry was performed using a low‐cost potentiostat designed for a Raspberry Pi single‐board computer. As a proof of concept, the constructed electrodes were tested with ferrocyanide and applied to quantify sucrose, and their performance was compared to that of the glassy carbon electrode. RESULTS The nanoparticles were successfully synthesized, as confirmed by morphology and physicochemical characterization. Based on the adjusted R2, the electrode made with the addition of copper oxide nanoparticles has a similar performance to the commercial glassy carbon electrode. All electrodes' root mean square error (RMSE) values were approximately 10−4 mol L−1. The lowest values for the inverse of the analytical sensitivity for sucrose were obtained for the unmodified carbon paste electrode (9.54 × 10−6 mol L−1) and copper oxide nanoparticles electrode (5.30 × 10−6 mol L−1). These electrodes also had the lowest limits of detection (10−5 mol L−1) and, for the limit of quantification, all electrodes had similar values (10−2 mol L−1). CONCLUSION In general, superior performance of carbon paste electrodes was observed concerning the commercial glassy carbon electrodes. Compared to previous studies, the developed electrodes showed good sensitivity and the low cost of the electrochemical system stands out as the main advantage. © 2022 Society of Chemical Industry (SCI).

Honey is a sweet substance that bees produce from the nectar of flowers. The geographic origin is an intrinsic factor for the characteristics of honey, which are evaluated through physicochemical analyzes that demand high analysis time and cost. Cyclic voltammetry can be used as an alternative analytical tool for the discrimination of honey samples, being a fast, simple, and inexpensive technique. This study aimed to apply cyclic voltammetry for honey origin authentication from Ortigueira (Paraná – Brazil) using graphite electrodes modified with nanoparticles of nickel oxide, iron oxide, copper oxide, and carbon nanotubes. The voltammograms collected were treated using chemometric methods for exploratory analysis and classification. The principal component analysis (PCA) demonstrated that cyclic voltammetry had better discrimination performance than the physicochemical analysis. The best classification model (PLS-DA) was also obtained with data from cyclic voltammetry with a percentage of correct classification for the prediction set of 94.44%. On the other hand, the PLS-DA model with physicochemical data achieved 88.57% of correct classification in the prediction set. The PLS-DA model using the voltammograms obtained with the developed electrodes showed more accuracy and greater selectivity when compared to the PLS-DA model built with the physicochemical data. Furthermore, the electrochemical system developed has low cost and allows quick analyzes that can be applied to verify the authenticity of the geographical origin of honey samples.