Direct Electrocatalytic Oxidation and Simultaneous Determination of 5-Methylcytosine and Cytosine at Electrochemically Reduced Graphene Modified Glassy Carbon Electrode

Direct electrocatalytic oxidation and simultaneous determination of 5-methylcytosine (5-mC) and cytosine(C) were realized in alkaline solutions by differential pulse voltammetry (DPV) based on an electrochemically reduced graphene oxide (er-GO) modified glassy carbon electrode (er-GO/GCE). The as-prepared er-GO/GCE exhibited good electrocatalytic activity towards the oxidation of 5-mC and C. Under optimum conditions, the er-GO/GCE was applied to the simultaneous determination of 5-mC and C with a significantly improved peak potential resolution (about 150 mV), and a linear relationship can be obtained in the range of 6–200.0 µmol/L and 8–250.0 µmol/L, respectively. In addition, the proposed method was further successfully applied to the analysis of methylation status in short CpG oligonucleotides with satisfactory results.