Copper polydopamine complex /multiwalled carbon nanotubes as novel modifier for simultaneouselectrochemical determination of Ascorbic acid, Dopamine, Acetaminophen, Nitrite and Xanthine

In this study, a novel modified glassy carbon electrode with copper polydopaminecomplex - multiwalled carbon nanotubes (GCE/Cu2+@PDA-MWCNTs) was fabricatedand used for voltammetric determination of ascorbic acid (AA), dopamine (DA),acetaminophen (AC), nitrite (Nit) and xanthine (XN). Different techniques such as fieldemission electron microscopy, transmission electron microscopy, Energy-dispersive Xrayspectroscopy, fourier transform infrared spectroscopy and electrochemical impedancespectroscopy were performed for characterization of the GCE/Cu2+@PDA-MWCNTs.Different electrochemical methods such as cyclic voltammetry, electrochemicalimpedance spectroscopy, differential pulse voltammetry (DPV) and Chronoamperometrymethods were employed to study the behavior of AA, DA, AC, Nit and XN on thisproposed modified electrode. The proposed modified electrode displays intense andindelible electrooxidation response for simultaneous determination of AA, DA, AC, Nitand XN to five well-separated peaks in the potential range from 0.1 to 1.1 V using CVand DPV methods in phosphate buffer solution with pH 2.0. Under the optimumconditions, the calibration carvers were liner up to 175, 125, 75, 150 and 115 μM withdetection 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 humanurine and serum samples.