Electrochemical determination of tannic acid using graphite electrodes sourced from waste zinc-carbon batteries

Abstract

A cost-effective and environment-friendly electrochemical sensor based on waste-battery graphite electrodes is developed. The electrodes were extracted from different brands of waste zinc‑carbon batteries and were used as the working electrode in differential pulse voltammetry (DPASV) for the electrochemical determination of tannic acid (TA). The bare graphite electrodes were pretreated using cyclic voltammetry and the surface morphology of the electrodes was studied using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. A linear TA concentration range from 2 parts per billion (ppb) to 60 ppb (R2 = 0.998) was obtained at optimized DPASV parameters. The limit of detection and limit of quantification were found to be 3.13 ppb and 9.49 ppb, respectively. The electrode was successfully utilized for the quantification of TA in commercially available Merlot wines. The most sensitive waste-battery electrode was sourced from Panasonic, and the Merlot wine procured from France yielded the highest tannic acid concentration. Keywords: Tannic acid, Differential pulse anodic stripping voltammetry, Cyclic voltammetry, Waste battery, Graphite electrode