▎ 摘　　要

A highly ultrasensitive electrochemical sensor based on electrochemically reduced graphene oxide (ERGO), Procion Red MX-5B (PR) and gold nanoparticles (AuNPs) modified glassy carbon electrode (GCE) was developed. Cyclic voltammetry (CV) was employed to electropolymerize GO-PR mixture on GCE followed by deposition of AuNPs to obtain ERGO-poly(PR)/AuNPs/GCE. The physical properties of the nanocomposite were explored through field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FT-IR). The electrochemical performance of the ERGO-poly(PR)/AuNPs/GCE showed remarkable enhancement in the peak current toward oxidation of AA, DA, and UA with peak potentials separation of 0.21 V for AA-DA, and 0.15 V for DA-UA. Differential pulse voltammetry (DPV) was applied to perform individual and simultaneous analysis of the aforementioned analytes at optimized pH. DPV responses of AA, DA, and UA concentration were obtained over the range of 0.4-110, 0.4-170 and 0.4-150 mu M with sensitivities of 0.48, 0.40, and 0.63 mu A/mu M (S/N = 3), respectively. Limit of detections for AA, DA, and UA were 54, 5.6 and 5.8 nM, respectively. Good repeatability, reproducibility as well as long-term stability were obtained. The developed modified electrode was used successfully to monitor AA, DA, and UA in vitamin C tablets, and human urine samples with favorable recoveries. (C) 2019 The Electrochemical Society.