Electrochemical modification of graphene oxide bearing different types of oxygen functional species for the electro-catalytic oxidation of reduced glutathione

The residual oxygen-containing functional species present on graphene play a crucial role in the electro-catalytic oxidation of some small molecules. Herein, graphene oxide (GO) modified glassy carbon (GC) electrode was electrochemically reduced at different potential and different types of oxygen functional species remained correspondingly on the surface of GO, which was presented for the electro-catalytic oxidation of reduced glutathione (GSH). The results showed that the GO modified electrode treated at −0.75 V for 1000 s exhibited the highest electro-catalytic oxidation toward GSH, however, no oxidation peak of GSH was observed when GO was completely reduced. The effect of various oxygen functional groups on the electro-catalytic oxidation of GSH was discussed. In addition, a GSH electrochemical sensor was developed based on the electrochemically modified GO and the effect of common interfering species was also investigated.