Copper polydopamine complex/multiwalled carbon nanotubes as novel modifier for simultaneous electrochemical determination of ascorbic acid, dopamine, acetaminophen, nitrite and xanthine

Abstract

In this study, a novel modified glassy carbon electrode with copper polydopamine complex/multiwalled carbon nanotubes (GCE/Cu2+@PDA-MWCNTs) was fabricated and used for voltammetric determination of ascorbic acid (AA), dopamine (DA), acetaminophen (AC), nitrite (Nit), and xanthine (XN). Different techniques such as field emission electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and electrochemical impedance spectroscopy were performed for characterization of the GCE/Cu2+@PDA-MWCNTs. Different electrochemical methods such as cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry (DPV) methods were employed to study the behavior of AA, DA, AC, Nit, and XN on this proposed modified electrode. The proposed modified electrode displays intense and indelible electrooxidation response for simultaneous determination of AA, DA, AC, Nit, and XN to five well-separated peaks in the potential range from 0.1 to 1.1 V using CV and DPV methods in phosphate buffer solution with pH 2.0. Under the optimum conditions, the calibration curves were liner up to 175, 125, 75, 150, and 115 μM with detection limits of 0.82, 0.45, 0.87, 0.92, and 0.67 μM for AA, DA, AC, Nit, and XN, respectively. This sensor was used to successfully determine these compounds in human urine and serum samples.