Gold/polypyrrole/Graphene oxide nanocomposite modified electrode for simultaneous determination of epinephrine, acetaminophen, and folic acid

Recently, electrochemical techniques using modified electrodes have been developed for simultaneous determination of biomolecules. Simultaneous determination of epinephrine (EP), acetaminophene (AC), and folic acid (FA) is of greater value because of their coexistence in biological systems [1]. Graphene has become one of the most exciting topics of research in the last decades, since it possesses several excellent attributes, including electronic, optical, and thermal properties, chemical and mechanical stability, and large surface area [2]. Polypyrrole (PPy), is one of the most promising Conducting polymers because of its ease of synthesis, good redox property, high conductivity, and excellent environmental stability [3].Gold nanoparticles, which are usually applied to bimolecular immobilization, have many advantages such as excellent catalytic activity, huge surface area, effective mass transport, and hospitable environment [4]. A novel biosensor graphene oxide (RGO)/ polypyrrole (PPy)/gold (Au) nanoparticles nanocomposite modified glassy carbon electrode (GCE) was prepared for simultaneous determination of epinephrine (EP), acetaminophen (AC) and folic acid (FA). Cyclic voltammetry and differential pulse voltammetry methods were used to investigate the modified electrode for the electrocatalytic oxidation of EP, AC, and FA in aqueous solutions. The separation of the oxidation peak potentials for EP-AC and AC-FA was about 210 and 270 mV, respectively. The calibration curves obtained for EP, AC, and FA were in the ranges of 0.4-260, 0.6-210, and 0.7-160 μM, respectively. The detection limits (S/N=3) were 0.071, 0.070, and 0.069 μM for EP, AC, and FA, respectively. Field emission-scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were employed to characterize the modified electrode.