A sensitive single-layered graphene oxide-based sensor for electrochemical sensing of phosphate anion

In recent years, the electrochemical determination of phosphate anion in aqueous solution has attracted widespread interest because of its potential to address the environmental, economic and health concerns associated with phosphate management protocol. Herein, we report a direct electrochemical approach to identify phosphates using a special architecture of single-layered graphene oxide (SLGO) with abundant oxygen-containing surface functional groups. The electrochemical adsorption of phosphate onto SLGO was confirmed by X-ray photoelectron spectroscopy (XPS), and the formation of covalent bonds between phosphorus and carbon atoms occurred through the partial conversion of C-O covalent bonds to C-O semi-ionic bonds, which was beneficial to the electrochemical performances of phosphate at SLGO. The electrochemical adsorption of phosphates at other carbon nanomaterials modified glassy carbon electrodes (GCE) and bare GCE was also carried out. Further characterization by XPS, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) revealed the electrochemical mechanism of SLGO/GCE toward phosphates. Under the optimized conditions, the concentration of phosphate was linearly related to the peak current in the range of 10.0-100.0 mu M with limit of detection (LOD) of 2.0 mu M (S/N = 3). More importantly, SLGO/GCE could be further extended to the quantitative detection of phosphate in industrial wastewater and human serum with acceptable recoveries (95.09-103.48%). This research could provide an effective method for the detection of trace phosphates in environmental media as well as physiological media.