Modified Glassy Carbon Electrode with Silver Nanoparticles/Polyaniline/Reduced Graphene Oxide Nanocomposite for the Simultaneous Determination of Biocompounds in Biological Fluids

The silver nanoparticles/polyaniline/reduced graphene oxide nanocomposite modified glassy carbon electrode (Ag/PANI/RGO/GCE) was prepared by the electrochemical method. The Ag/PANI/RGO nanocomposite was characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, X-ray diffraction (XRD), and electrochemical impedance spectroscopy (ESI). Two electrochemical techniques namely differential pulse voltammetry (DPV) and cyclic voltammetry (CV) were used to the electrochemical behaviors investigation of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The Ag/PANI/RGO/GCE exhibited remarkable electrocatalytic activity towards the oxidation reaction of AA, DA, and UA in Britton-Robinson (BR) solution (pH=4.0). Under the optimal conditions, the determinations of AA, DA, and UA were accomplished using DPV. AA-DA and DA-UA peak potential separations were 130 and 180 mV, respectively. For simultaneous detection, the linear response ranges were in the two concentration ranges of 0.05-0.8 mM and 2.0-16.0 mM with detection limit 0.412 mu M (S/N = 3) for AA, 0.7-90.0 mu M and 90.0-1000.0 mu M with detection limit 0.023 mu M (S/N = 3) for DA, and 0.8-70.0 mu M and 70.0-1000.0 mu M with detection limit 0.050 mu M (S/N = 3) for UA. This modified electrode showed good sensitivity, selectivity, and stability with applied to determine AA, DA, and UA in human urine and drug.