WO3 nanoparticles based direct electrochemical dopamine sensor in the presence of ascorbic acid

Tungsten trioxide (WO3) nanoparticles with monoclinic (gamma) and orthorhombic (beta) structures were synthesized by a simple microwave irradiation method and characterized using powder X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), Raman spectroscopy, field emission scanning electron microscopy (FESEM), UV-vis absorption and photoluminescence (PL) spectroscopy studies. The gamma-WO3 nanoparticles modified glassy carbon electrode (GCE) showed an excellent electrocatalytic activity towards the oxidation of dopamine (DA) in the presence of ascorbic acid (AA) at pH 7.0. Electrochemical kinetic parameters of gamma-WO3/GCE such as electroactive area A (0.045 cm(2)), electron transfer coefficient a (0.71) and electron transfer rate constant k(s) (1.121 s (1)) were calculated and compared with that of beta-WO3/GCE. Differential pulse voltammetry (DPV) studies of the gamma-WO3 modified GCE exhibited a linear response over a wide concentration range of 0.1 mu mol L (1)-600 mu mol L (1) of DA with the lowest detection limit of 24 nmol L (1). The fabricated dopamine sensor showed an excellent anti-interference ability against electroactive species and metal ions with good stability and reproducibility. Finally, the developed sensor was applied to determine DA concentration in dopamine hydrochloride injection which indicates that this electrode can be effectively used for real sample analysis. (C) 2015 Elsevier Ltd. All rights reserved.