One-pot synthesis of Au-Cu2O/rGO nanocomposite based electrochemical sensor for selective and simultaneous detection of dopamine and uric acid

Abstract A Au-Cu2O/rGO nanocomposite based electrochemical sensor for selective and simultaneous detection of dopamine and uric acid was developed. The nanocomposite was prepared by a one-pot synthesis method and the resulted product was characterized by transmission electron microscope (TEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS). From TEM image, the presence of Au-Cu2O supported on rGO sheets were identified. The XRD analysis reveals the face centered cubic (FCC) structure of Au-Cu2O nanoparticles and the XPS spectrum showed the presence of the constituent elements in the nanocomposite. The electrochemical studies on the Au-Cu2O/rGO nanocomposite towards dopamine (DA) and Uric Acid (UA) were tested using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The CV studies showed enhanced catalytic activity for dopamine due to the synergistic effect of the ternary nanocomposite which was also further supported by the increased surface roughness of the material. From DPV, the detection limit of 3.9 μM and 6.5 μM and linear range of 10–90 μM and 100–900 μM was estimated for DA and UA. The selective and simultaneous detection of DA and UA was demonstrated. The sensor shows long term stability and reproducibility. Quantification of DA and UA in biological fluid samples (ie human serum and urine) has also been carried out to prove the practical applicability of the sensor.