Electrochemical sensor for thiourea focused on metallurgical applications of copper

[Display omitted] •Direct monitoring of thiourea in copper electrorefinery baths is presented.•A disposable electrode is modified with silver nanoparticles in a polymeric matrix.•Square wave voltammetry was successfully applied for the quantification of thiourea.•The involved mechanism is evaluated by a coupled electrochemical and IR analysis. A simple and reliable device is presented for the direct monitoring of thiourea in copper electrorefinery baths as a tool for reconditioning of industrial baths, and so reducing its environmental impact. For this purpose, a screen-printed graphite electrode is modified with silver nanoparticles (AgNPs) contained in a polyelectrolyte-surfactant matrix. The AgNPs are able to adsorb the thiourea, improving the sensitivity of the electrode toward this analyte, even in the presence of usual additives (Avitone® and glue). The system allows the determination of thiourea in a range of 1–10mg/L. A coupled electrochemical and IR analysis is proposed to evaluate the involved mechanism.