Simultaneous detection of ascorbic acid and dopamine with electrochemically pretreated carbon nitride electrodes: Comparison with boron-doped diamond electrodes

Amorphous carbon nitride (a-CNx) electrodes were successfully tested as substitutes to boron-doped diamond (BDD) electrodes for the simultaneous voltammetric detection of dopamine (DA) and ascorbic acid (AA). For both materials, the same anodic pretreatment in alkaline medium was necessary to attain adequate and equivalent separation of the oxidation potential peaks. The electrochemical response of the a-CNx electrode in terms of peak current values and potentials was reproducible after each anodic pretreatment in alkaline medium. For BDD, DA oxidation was insensitive to anodic or cathodic pretreatments, whereas, for a-CNx, it was catalyzed by the anodic pretreatment. On the other hand, AA oxidation was catalyzed by the cathodic pretreatment for both electrodes. (C) 2012 Elsevier B.V. All rights reserved.