Determination of Gallic Acid in Tea by a Graphene Modified Glassy Carbon Electrode

The determination of gallic acid (GA) content by a graphene modified glassy carbon electrode (graphene/GCE) was studied. The electrochemical behavior of GA on this electrode was studied by cyclic voltammetry (CV), and the standard curve was constructed by differential pulse voltammetry (DPV). The results indicate that graphene has a good catalytic effect on GA in phosphate buffer (PBS) and shows a linear response toward GA in the 8.0 x 10(-8) to 2.0 x 10(-5) mol.L-1 concentration range. The detection limit is 1.2 x 10(-9) mol.L-1. This proposed determination for GA on graphene/GCE was carried out in the presence of potentially interfering compounds such as sorbic acid, tartaric acid, ascorbic acid and glucose. The content of GA in green tea was determined by this method, and the recovery was 97.9% - 100.6% with satisfactory results.