A highly sensitive electrochemical sensor for simultaneous voltammetric determination of noradrenaline, acetaminophen, xanthine and caffeine based on a flavonoid nanostructured modified glassy carbon electrode

For the first time, simultaneous voltammetric determination of Noradrenaline (NA), Acetaminophen (AC), Xanthine (XN) and Caffeine (CF) has been investigated at a flavonoid nanostructured sensor. The construction of modified electrode was performed through the electrodeposition of luteolin on a functionalized multi-wall carbon nanotube immobilized on the surface of a glassy carbon electrode (Lt/fMWCNT/MGCE). During modification process, luteolin is oxidized to the corresponding o-quinone derivative and attached to the surface of fMWCNT/GCE through Michael type addition reaction. Electrochemical properties of the modified electrode were investigated by electrochemical impedance spectroscopy (EIS). The Lt/fMWCNT/MGCE offered substantially lower overpotential for electro-oxidation of NA, AC, XN and CF in phosphate buffer solution (pH 7.0) compared with Lt/GCE, fMWCNT/GCE and bare GCE. Differential pulse voltammogram peak currents of NA, AC, XN and CF increased linearly with their concentration at the ranges of 0.7-100.0 μM, 0.9-80.0 μM, 1.0-70.0 μM and 10.0-110.0 μM, respectively, and the detection limits for NA, AC, XN and CF were sequentially 0.53 μM, 0.78 μM, 0.65 μM and 3.54 μM. Furthermore, this electrochemical sensor was successfully implemented for the determination of NA in pharmaceutical samples using standard addition method and the obtained results were found to be satisfactory.