Ferricyanide/reduced graphene oxide as electron mediator for the electrochemical detection of methanol in canned citrus sinensis and citrus limetta

The quality of exported canned citrus sinensis and citrus limetta degrades slowly owing to the excess liberation of methanol from the pectin of canned citrus sinensis and citrus limetta. To detect the methanol liberation, an electroactive inorganic-organic nanocomposite modified working electrode was fabricated by immobilizing reduced graphene oxide/ferricyanide (rGO/Fe(CN)63−) on the surface of Pt electrode via chitosan membrane. The electrocatalytic oxidation of methanol by Fe(CN)63− was observed at the anodic potential of 243 mV (vs Ag/AgCl), which was shifted negatively to almost 36 mV when compared with that of direct electrochemical oxidation of Fe(CN)64− in the Pt/Chitosan/rGO/Ferricyanide electrode. The developed amperometric sensor could detect methanol concentration down to 12 nM with a linearity of 1-7 mM, sensitivity of 0.479 μA mM−1, reproducibility of 1.2% RSD, repeatability of 1.1% RSD, response time of less than 10 s with the stability of 98% over a period of 20 days.