Electrochemical Detection of Gallic Acid using Zinc Oxide/Graphene Oxide Hybrid Nanocomposite-modified Electrode

Background: Gallic acid (GA) is an important biomarker with significant relevance in the food, pharmaceutical, and environmental industries, requiring highly sensitive and selective detection techniques. Aim: This study presents the development of a robust electrochemical sensor for GA detection, utilizing a zinc oxide/graphene oxide (ZnO/GO) nanocomposite-modified electrode, with a focus on applications for assessing the impact of GA on oral health. Methods: GO was synthesized via a modified Hummers' method, while ZnO nanoparticles with rodshaped morphology were prepared hydrothermally. The ZnO/GO composite film was created by combining their dispersions and thermal treatment. Results: UV-visible spectra confirmed the interaction between ZnO and GO through redshift, and FTIR analysis revealed characteristic Zn-O and C-O bonds. Cyclic voltammetry (CV) demonstrated that the ZnO/GO-modified electrode detects GA at a remarkably low potential (0.1 V vs. Ag/AgCl) compared to previously reported GA sensors. Conclusion: This new sensor exhibited a low detection limit of 0.31 × 10-4 M and a wide linear response range from 50 – 250 μM with excellent sensitivity (slope = 0.0537 μA/μM, R² = 0.9971). In the future, this sensor may find some application in the field of dentistry to monitor the efficacy of the GA for patients undergoing dental treatments like dentin hypersensitivity, proliferation of oral bacteria, oral ulcer, plaque, remineralization, and gingivitis.