Fast and Sensitive Detection of Bisphenol A and 4-n-Octylphenol in Foods Based on a 2D Graphitic Carbon Nitride (g-C3N4)/Gold Nano-Composite Film

In this paper, graphite phase carbon nitride (g-C 3 N 4 ) was prepared by one-step high temperature thermal decomposition method, and layered g-C 3 N 4 was prepared by protonation with concentrated hydrochloric acid. The morphology and composition of g-C 3 N 4 were characterised by transmission electron microscope (TEM), energy dispersive spectroscopy (EDS) and X-ray powder diffraction (XRD). Furthermore, the AuNPs-g-C 3 N 4 /GCE was constructed by coating method and potentiostatic deposition method, and the construction process and resistance change of the electrodes were characterised by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The experimental results indicated that the AuNPs-g-C 3 N 4 /GCE has excellent electrocatalytic performance for bisphenol A (BPA) and 4-n-octylphenol (OP). Under optimized experimental conditions, BPA and OP were detected by differential pulse voltammetry (DPV) at the AuNPs-g-C 3 N 4 /GCE. The linear ranges were 0.1–6.5 µmol L −1 and 0.1–3.8 µmol L −1 for BPA and OP, wtih the detection limits of 0.0176 µmol L −1 and 0.0324 µmol L −1 , respectively. In addition, the AuNPs-g-C 3 N 4 /GCE showed satisfactory reproducibility and stability and can be successfully applied to monitor of BPA and OP in baby formula samples.