Voltammetric Determination of Gallic Acid with a Glassy Carbon Electrode modified with Reduced Graphene Oxide

Gallic acid is a valuable compound that is present or incorporated in a variety of foods, beverages, cosmetics, and other chemical formulations. However, the cost-efficient determination of gallic acid over a wide range of concentrations is an unsolved problem. In this work, we propose a reduced graphene oxide (rGO)-modified electrode design that is easy to manufacture in a highly repeatable manner, does not involve toxic chemicals or fragile components, and offers superior sensitivity and linear dynamic range. Application of the electrode is demonstrated and optimized with common cyclic voltammetry and square-wave voltammetry system; the latter being recommended for quantification. The electrode is reusable, very robust to common interferents, and is shown to yield precise determinations in real samples, even at very low gallic acid concentrations.