Hybrid Electrocatalytic Nanocomposites Based on Carbon Nanotubes/Nickel Oxide/Nafion toward an Individual and Simultaneous Determination of Serotonin and Dopamine in Human Serum

Abstract

Abstract The design and development of facile, rapid, selective, and sensitive electroanalytical methods for the simultaneous determination of serotonin (ST) along with other interfering species are in huge demand. To address this, herein, we report an efficient electrochemical sensing platform for the individual and simultaneous determination of ST and dopamine (DA) in human serum. The sensing system was judicially constructed by hybrid electrocatalytic nanocomposites composed of carbon nanotubes/nickel oxide/carbon black/Nafion modified screen-printed carbon electrode (CNT-NiO-CB/Nafion/SPCE). The structural, morphological, and electrochemical properties of the as-synthesized/fabricated materials and electrodes were thoroughly analyzed through appropriate instrumentations (scanning/transmission electron microscopy, electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, etc.). Besides, the experimental parameters of electrochemical measurements, such as varying amounts (CNT-NiO-CB/Nafion), pH, conditioning potential, time, modulation amplitude, and step potential, have been carefully optimized. The as-fabricated newly designed sensor exhibits superior analytical performance such as wide linear range (0.06–7.50 µM ST and 0.08–6.00 µM DA), low limit detection of (11 nM ST and 11 nM DA), high reproducibility (RSD = 5.74% ST and 7.74% DA) indicating excellent selectivity, stability, sensitivity along with good recovery range.