Conducting Nickel Hydroxide Thin Film on Molybdenum Disulfide – Reduced Graphene Oxide Composite Electrode for Simultaneous Detection of Uric Acid, Dopamine and Ascorbic Acid

Herein we report the fabrication of a simple electrochemical sensor based on an electrode containing reduced graphene oxide and molybdenum disulphide (RGO/MoS₂) as a conducting film onto the glassy carbon electrode (GCE) via a drop dry method to form GCE-RGO/MoS₂. The surface (GCE-RGO/MoS₂) was further modified with nickel hydroxide thin film using electrodeposition method to form GCE-RGO/MoS₂/Ni(OH)₂. The materials and modification steps were thoroughly characterized using microscopy and spectroscopy methods. The composite electrode, GCE-RGO/MoS₂/Ni(OH)₂, showed excellent electrocatalytic potential separation for the detection of dopamine, uric acid, and ascorbic acid. The electrocatalytic oxidation peak potentials were at 3 mV, 157 mV and 303 mV for AA, DA and UA, respectively. The composite electrode was also selective towards the determination of ascorbic acid (AA), dopamine (DA), uric acid (UA), and simultaneously in mixture of analytes. The low detection limits for AA, DA and UA were 1.17 μM, 0.15 μM and 1.15 μM, respectively. The composite electrode was applied for the detection of AA, DA and UA in spiked newborn calf serum samples with high percentage recoveries ranging from 96.6–100.8 % for AA, 92.8–104.2 % for DA and 99.4–102.3 % for UA.