Ultrasensitive Determination of Dopamine and Uric Acid Based on Gold Nanoparticles@Carbon Dots/Electrochemical Reduced Graphene Oxide modified glassy carbon electrode

Abstract

An ultrasensitive electrochemical sensing platform based on a glassy carbon electrode (GCE) modified with electrochemically reduced graphene oxide (erGO) and gold nanoparticles@carbon dots (GNPs@CDs) was developed. The hydroxyl-rich CDs were electrochemically synthesized, and the GNPs@CDs were obtained by reducing chloroauric acid with hydroxyl-rich CDs. The electrochemical behavior of the fabricated electrode, GNPs@CDs/erGO/GCE, was explored by cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical performance of the electrode demonstrated a remarkable enhancement in the peak current toward oxidation of dopamine (DA) and uric acid (UA) with a peak potential separation of 0.15 V in the presence of ascorbic acid (AA). Under optimized conditions, the simultaneous determination of DA and UA was investigated using differential pulse voltammetry (DPV) resulting in a linear response in the concentration ranges of 0.01−5.0 μM and 5.0−20.0 μM for DA and of 0.1−20.0 μM and 20.0−50.0 μM for UA and in a sensitivity of 11.96 and 6.48 μA μM, respectively. The prepared electrode also demonstrated longterm stability and good reproducibility and was successfully used for the determination of DA and UA in human serum samples with favorable recoveries.