Electrocatalytic oxidation of kojic acid at a reduced graphene sheet modified glassy carbon electrode

A simple procedure has been developed to prepare a glassy carbon (GC) electrode modified with reduced graphene sheets (RGSs) (RGSs/GC). The electrocatalytic oxidation of kojic acid on the RGSs/GC electrode in 0.2 M HAc–NaAc buffer solution has been studied using cyclic voltammetry and chronoamperometry. Compared with the unmodified GC electrode, a decrease in overpotential and large enhancement of oxidation current for kojic acid oxidation has been achieved with the RGSs/GC electrode. The kinetic parameters of the kojic acid oxidation reaction electrocatalyzed by RGSs have also been calculated. The diffusion coefficient of kojic acid has been estimated as 1.5 × 10−5 cm2 s−1 for the experimental conditions, using chronoamperometry. The transfer coefficient for electron transfer and the number of electrons transferred in the overall reaction have been calculated to be 0.53 and 1, respectively. Under the optimized conditions, the oxidation peak current was proportional to kojic acid concentration in the range of 0.01–0.14 mM with a current sensitivity of 42.9 μA mM−1 and correlation coefficient of 0.9950, suggesting that RGSs are a potential electrode material for electrochemical sensors for kojic acid detection.

► Reduced graphene sheets (RGSs) modified glass carbon electrode was fabricated.
► The modified electrode showed excellent catalytic ability towards kojic acid.
► Kojic acid is oxidized mainly through a one-electron, one proton process.
► RGSs are suitable as electrode material to detect kojic acid.