▎ 摘　　要

In this research, the electrochemical method was used as a tool with the newly proposed electrode to detect dopamine (DA) in the urine sample. Gold/Poly3,4-ethylene-dioxythiophene/reduced-graphene oxide (AuNPs/PEDOT/rGO) nanocomposite material was synthesised via the facile one-pot method. The presence of Au/PEDOT on the rGO sheet was investigated by Fourier Transform Infrared (FTIR) spectrometer, Scanning Electron Microscope (SEM) and Ultraviolet-visible (UV-vis) spectroscopy. The synthesised nanocomposite material was then drop-casted on bare glassy carbon electrode (GCE) to improve the detection performance. The electrochemical behaviour of AuNPs/PEDOT/rGO/GCE was studied by Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). Under optimum condition, the AuNPs/PEDOT/rGO/GCE showed linear voltammetric response in the concentration 20 to 200 nM for DA with the detection limit (LOD) and detection quantitation (LOQ) of 1.04 and 3.47 nM, respectively. This developed sensor was applied to human urine sample with good percentage recovery of 88.31%. It also exhibited good reproducibility and repeatability with relative standard error (RSD) of 9.58% and 2.7%, respectively. Hence, the proposed modified electrode offers an exceptional selectivity and high sensitivity towards the electrochemical sensing of dopamine in human samples.