(Digital Presentation) Dopamine Detection at Green Carbon Quantum Dots Based Electrochemical Sensor

This work describes the fabrication and application of a sensor based on green carbon quantum dots/copper oxide nanocomposite for dopamine (DA) detection. The characterization of the copper oxide nanoparticles (CuO NPs), green carbon quantum dots prepared from banana peels (gCQDs), and their composite (gCQDs/CuO) was effected through Fourier Transform infrared spectroscopy (FT-IR), UV-visible spectroscopy, X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and thermogravimetric analysis. The comparative cyclic voltammogram of the CuO NPs modified glassy carbon electrode (GCE) (CuO/gCQDs), gCQDs modified GCE (gCQDs/GCE), and the nanocomposite modified GCE (gCQDs/CuO/GCE) shows that the composite modified GCE has the best electrocatalytic activity towards DA detection. The Nyquist plot of electrochemical impedance spectroscopy (EIS) data revealed that the composite modified GCE possesses the lowest charge transfer resistance (Rct). Using the square wave voltammetry (SWV), this sensor offered a limit of detection (LoD) of 25.41 µM over a linear range of 50-200 µM. The real sample analysis of DA in dopamine hydrochloride injection shows that the proposed sensor is capable of 94.8 % DA recovery from the real sample solution. The sensor also offered selective DA detection in the presence of ascorbic acid (AA).