Electrochemical Quantification of Gallic Acid: The Role of Voltammetric Parameter Optimization via Multivariate Experimental Design

Abstract

The increasing demand for pomegranate-based supplements highlights the need for accurate quantification of bioactive compounds such as gallic acid (GA), a phenolic marker associated with antioxidant effects. This study evaluates how square wave voltammetry (SWV) parameters—frequency, potential increment, and pulse amplitude—directly influence the current response associated with GA electrooxidation on gold electrodes in an acidic medium. Cyclic voltammetry and SWV were used, with parameter optimization performed via central composite rotatable design and response surface methodology. Frequency and amplitude showed the greatest influence on the current signal, while potential increment had a minor effect. The optimized conditions (180 Hz, 5 mV, and 25.5 mV) enabled GA quantification in powdered pomegranate and commercial supplements, with concentrations of 0,6105 mmol L⁻¹ e 0,7106 mmol L⁻¹, respectively. The method exhibited linearity from 10 to 100 µmol L⁻¹, with limits of detection and quantification of 5.03 and 16.78 µmol L⁻¹. This optimized electrochemical approach offers a fast, sensitive, and reliable tool for quality control in natural products.