Development of a Functionalized SiO2 Supported Ni Nanoparticles Based Non-Enzymatic Amperometric Dopamine Sensor

In the present work, a novel electrochemical dopamine (DA) sensor depending on Nickel (Ni) nanoparticles decorated (3-aminopropyl)triethoxysilane (APTES) modifed silica (SiO2) was fabricated. Hence, Ni@SiO2-APTES was synthesized by the conventional wet-impregnation method. The structure of the compozite was evaluated using Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy-energy dispersive X-ray (SEM-EDX), and X-ray diffraction (XRD). The synthesized Ni@SiO2-APTES was loaded on glassy carbon working electrode (GCE). Also, Nafion (Nf) was drop-casted on Ni@SiO2-APTES/GCE to stabilize the electrode. The fabricated Nf/Ni@SiO2-APTES/GCE working electrode was electrochemicaly evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometry. CV and EIS results indicated that Ni nanoparticles increased both the conductivity and sensitivity of the working electrode. The linear detection range for DA was found to be 0.2 – 252 µM with limit of detection (LOD) was 0.07 µM depending on S/N of 3. The sensitivity was found to be 578.26 µA mM-1 cm-2 depending on the active surface area of the modified working electrode. The sensor exhibited excellent selectivity in the electrolyte solution including ascorbic acid, glucose, fructose, sucrose, mannose, uric acid, and phenylalanine. The sensor had satisfactory repeatability and reproduciblity. It was observed that the sensor showed an electrocatalytic response of 95.33% after 28 days. According to this result, it was concluded that the sensor was extremely stable within the studied time period. The applicability of Nf/Ni@SiO2-APTES/GCE was tested using dopamine HCl injection (200 mg/5 mL).