Simultaneous electrochemical determination of ascorbic acid, dopamine and uric acid using a palladium nanoparticle/graphene/chitosan modified electrode

A palladium nanoparticle/graphene/chitosan/glassy carbon electrode (PdNPs/GR/CS GCE) was prepared and characterized in this paper. This chemical modified electrode displayed excellent eletrochemical catalytic activities towards ascorbic acid (AA), dopamine (DA) and uric acid (UA) compared with bare GCE, PdNPs/GCE and GR/CS GCE by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). All oxidation potentials of AA, DA and UA at the PdNPs/GR/CS GCE shifted negatively and the peak currents were much larger than other electrodes. DPV was used for simultaneous determination of AA, DA and UA in their mixture, and the peak potential separations between AA and DA, DA and UA, AA and UA were 252 mV, 144 mV and 396 mV, respectively. The limits of detection (S/N = 3) for AA, DA and UA were 20 μM, 0.1 μM and 0.17 μM, respectively. This PdNPs/GR/CS GCE showed many merits in stability, sensitivity, facility and economy.

► A novel material, graphene with excellent film forming ability was prepared.
► The electrode was based on graphene, chitosan and palladium nanoparticles.
► The direct electrochemistry of AA, DA and UA oxidase was realized.
► The sensor could separate AA, DA and UA signals into three well-defined voltammetric peaks.