Determination of gallic acid using poly(glutamic acid): graphene modified electrode

Gallic acid (GA) is one of the main phenolic components occurring naturally in plants and has been a subject of increasing interest owing to its antioxidant, anti-mutagenic and anti-carcinogenic properties. The present work describes a rapid and cost-effective analytical procedure for the determination of gallic acid. Poly-Glu/rGO electrode was fabricated by the electro-polymerisation of glutamic acid on reduced graphene oxide (rGO) modified paraffin impregnated graphite electrode (PIGE). The modified electrode was characterized by SEM, AFM and ATR-IR. The electrochemical behavior of gallic acid at the modified sensor was studied by voltammetric and amperometric techniques under optimized conditions in pH 5 acetate buffer. The electrode showed good linear response towards the determination of gallic acid over the range of 0.03–480 μ M with 0.01 μ M as the detection limit for voltammetric technique and the amperometric technique showed a linear range of 1–17 μ M with 0.33 μ M as the detection limit. The electrode also showed good stability and reproducibility with a sensitivity of 0.97 μ M / μ A. The proposed method can be applied to detect GA in real samples with satisfactory results. Graphical abstract SYNOPSIS This work describes a rapid and cost-effective analytical procedure for the determination of gallic acid. Poly-Glu/rGO electrode was fabricated by electro-polymerisation of glutamic acid on reduced graphene oxide (rGO) modified paraffin impregnated graphite electrode (PIGE). The electrode showed linear response towards gallic acid over the range of 0.03–480 μ M with 0.01 μ M as the detection limit for voltammetric technique and a linear range of 1–17 μ M with 0.33 μ M as the detection limit for amperometric technique. The proposed electrochemical sensor can be applied to detect GA in real samples with satisfactory results.