Electroanalytical Detection of Flavonoid Rutin Using a SPCE Modified with Manganese Oxide Recycled with Hydrothermal Treatment

This report presents a novel protocol for the recovery and utilization of recycled manganese oxide from used batteries through hydrothermal (HT) treatment. The recovered and treated material showed high activity towards rutin electro-oxidation (RT) on a screen-printed carbon electrode (SPCE) modified with recovered and treated MnO2 within a hydrothermal reactor. Material characterization using scanning electron microscopy (SEM) and density distribution and particle size analysis revealed a more homogeneous and less dispersed particle size compared to the untreated material. This treatment increased the electroactive activity of the anodic current for RT by more than 70% compared to the SPCE without MnO2 treated with HT. The electroanalytical application of this new electrode enabled the detection of RT, with a detection limit of 0.03 µmol/L, and its application in natural samples such as coffee and flavored beverages.