A combined experimental-computational approach for electrocatalytic detection of epinephrine using nanocomposite sensor based on polyaniline/nickel oxide

Abstract

• A novel electrochemical sensor based on GCE/PANI/NiO nanocomposite developed for epinephrine. • Very good performances achieved at a molecular level (detection limit: micromolar; recoveries > 100% and reasonable RSDs) • The nanocomposite is cost effective, sensitive and reproducible. • Excellent practical applicability in real sample (adrenaline injection) analysis. • Computational simulations validated experimental results at an atomistic level. This study reports on a sensor based on nickel oxide nanoparticles (NiO) derived from callistemon viminalis leaf extract and the polymerization of polyaniline (PANI) supported on a glassy carbon electrode (GCE). The novel 2D sensing materials for epinephrine (EP) have been experimentally investigated and theoretically modelled. The electrochemical sensor based on GCE/PANI/NiO exhibits good sensitivity and selectivity for EP. Under optimized conditions, the oxidation peak currents of EP showed a linear dynamic range of 47–354 μM with limit of detection of 0.05 µM using square wave voltammetry. The designed sensor demonstrated good practicability for the detection of EP in adrenaline injection with good recoveries (102.0 to 105.3%) and precision (RSD of 0.22–2.15%). The Monte Carlo and molecular dynamics simulations were used to assess the active sites of the adsorbate–substrate interface and the computed binding affinities of GCE/PANI/NiO toward EP. The density functional theory calculations confirm the chemical reactivity and stability of EP with HOMO-LUMO energy band gap of −5.48 eV. This opens an insightful and new path to expand the fabrication of novel sensors based on 2D materials using a combined experimental-computational approach.