Oxidation potential-dependent selective detection of epigenetic 5-hydroxymethylcytosine using nanocarbon film

•The sputtered nanocarbon film electrode with wide potential window and lower background current was developed.•Epigenetic mark 5-hydroxymethylcytosine (5hmC) can be oxidized sufficiently with the nanocarbon film electrode.•We successfully used the nanocarbon film electrode in combination with HPLC to detect 5hmC from gDNA.•Controlling the applied oxidation potential was very effective for the quantitative and selective detection of 5hmC in gDNA.