Simultaneous Electrochemical Sensing of Dopamine, Ascorbic Acid, and Uric Acid Using Nitrogen-Doped Graphene Sheet-Modified Glassy Carbon Electrode

Abstract

Nitrogen (N) doping is a well-known approach that can be effectively used to tune the properties of graphene-supported materials. The current attempt followed a simple hydrothermal protocol for the fabrication of N-doped graphene sheets (N-GSs). The N-GSs were subsequently applied to modify the surface of a glassy carbon electrode (GCE) for a dopamine (DA) electrochemical sensor (N-GSs/GCE), tested on the basis of differential pulse voltammetry (DPV). The findings highlighted a limit of detection (LOD) as narrow as 30 nM and a linear response in the concentration range between 0.1 and 700.0 μM. The modified electrode could successfully determine DA in the co-existence of uric acid (UA) and ascorbic acid (AA), the results of which verified the potent electrocatalytic performance of the proposed sensor towards AA, DA, and UA oxidation, and three distinct voltammetric peaks at 110, 250, and 395 mV via DPV. The practical applicability of the as-developed N-GSs/GCE sensor was confirmed by sensing the study analytes in real specimens, with satisfactory recovery rates.