Highly sensitive simultaneous determination of cadmium (II), lead (II), copper (II), and mercury (II) ions on N-doped graphene modified electrode

• The N-doped graphene was obtained by a one-step electrochemical strategy.
• The N-doped graphene can be used for the simultaneous detection of four metal ions.
• Low detection limit with wide linear range could be obtained.
• The method was successfully applied in real samples.

Toxic heavy-metal ions are well known to be severely harmful to human health. Therefore, the development of fast and sensitive methods for their detection has drawn a great attention in recent years. Herein, a sensitive electrochemical platform for the simultaneous determination of Cd2 +, Pb2 +, Cu2 +, and Hg2 + has been constructed based on N-doped graphene (NG) modified electrode using differential pulse stripping voltammetry (DPSV). NG was synthesized by a facile, efficient and green electrochemical method. The structure and composition of NG were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron microscopy (XPS) techniques, chronocoulometry and N2 adsorption–desorption measurements. The NG modified electrode showed excellent catalytic activity for selective detection of Cd2 +, Pb2 +, Cu2 +, and Hg2 + due to its particular structure and unique electronic properties. Under optimal conditions, the limits of detection were estimated to be 0.05 μM for Cd2 + and Hg2 +, 0.005 μM for Pb2 + and Cu2 +, respectively. Finally, the method was applied to the simultaneous detection of trace metal ions in the tap water samples.