Simultaneous Detection of Ascorbic Acid, Dopamine, and Uric Acid Using a Novel Electrochemical Sensor Based on Palladium Nanoparticles/Reduced Graphene Oxide Nanocomposite

A fresh strategy based on two-step electrochemical reduction for the fabrication of palladium nanoparticles/reduced oxide nanocomposite-modified glass carbon electrode (PdNPs/rGO/GCE) was established in this study. Field emission scanning electron microscopy (FESEM) images showed that spherical PdNPs were evenly distributed on the surface of rGO-modified electrode (rGO/GCE), and the introduction of PdNPs has no effect on the morphology of rGO. Electrochemical impedance spectroscopy (EIS) studies revealed that the conductivity of PdNPs/rGO/GCE was higher than that of rGO/GCE and bare GCE. The electrochemical performances of PdNPs/rGO/GCE sensor were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and chronoamperometry using ascorbic acid (AA), dopamine (DA), and uric acid (UA) as analytes. At the optimized conditions, wide linear ranges of 0.5–3.5 mM (R2 = 0.99), 3–15 μM (R2 = 0.99) and 15–42 μM (R2 = 0.99), and 0.3–1.4 mM (R2 = 0.99) towards AA, DA, and UA in ternary mixture were observed, respectively. In addition to superior anti-interference capability, fast response (≤5 s), excellent reproducibility, and good long-term stability were also given by this sensor. These results suggested that PdNPs/rGO/GCE is promising for the simultaneous detection of AA, DA, and UA in practical application.