Electrochemical sensor prepared with materials from spent Zn-MnO 2 batteries for copper(II) determination in alcoholic beverages

In this study, square wave voltammetry (SWV) and screen-printed carbon electrodes (SPCE) modified with a composite film of corn starch and cathode active material (CAM) from spent Zn-MnO 2 batteries were used to develop a portable, fast, and sustainable method to determine copper in alcoholic beverages. The composite electrode was characterized by Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS). SWV operational parameters for copper determination were optimized using an experimental design approach. Optimal values were found to be as follows: step potential of 10 mV, modulation amplitude of 80 mV, and frequency of 4 Hz. A 0.1 mol L −1 H 2 SO 4 solution was used as a supporting electrolyte. The method obtained a limit of detection of 0.024 μmol L −1 ( R 2 = 0.997). No matrix effects were detected in recovery tests with cachaça, whisky, vodka, gin, or beer.