Electrochemical deposition of gold nanoparticles on reduced graphene oxide modified glassy carbon electrode for simultaneous determination of levodopa, uric acid and folic acid

• We have prepared a DHB self-assembled monolayer at GNPs/RGO/GCE to determine levodopa.
• The proposed sensor showed a low detection limit of 18 nM for levodopa.
• A method for simultaneous determination of levodopa, uric acid and folic acid.
• Ease of preparation, high repeatability and stability are characteristics of the electrode.

A novel assembly of graphene oxide (RGO), gold nanoparticles and 2-(3,4-dihydroxy phenyl) benzothiazole (DHB) modified glassy carbon electrode (DHB/AuNPs/RGO/GCE) was successfully fabricated by chemical and electrochemical deposition of gold nanoparticles at RGO/GCE and characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. This sensor was applied to simultaneous determine levodopa (LD), uric acid (UA) and folic acid (FA). It was observed that an electrochemical deposition of gold nanoparticle has higher electrocatalytic activity for the oxidation of LD, UA and FA compared with chemical deposition. Square wave voltammograms of these compounds showed three well defined and fully resolved anodic oxidation peaks with large current at DHB/AuNPs/RGO/GCE. The proposed electrode was successfully applied for determination of LD, UA and FA in some real samples (such as tablet of Madopar, urine and human blood serum) by the standard addition method.

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