Abstract
This composite was prepared from zirconium tungstate Zr(WO4)(2) and graphene oxide (GO) by in-situ chemical reduction of a mixture containing GO and Zr(WO4)(2). The morphology and structure of the composite were confirmed by various physicochemical techniques. The materials was used in a tyrosinase-based micro biosensor where the enzyme is immobilized in a biocompatible matrix consisting of poly(o-phenylenediamine) and GO-Zr(WO4)(2). The composite was deposited on the surface of an 8-mu m thick carbon fiber microelectrode. The role of each component in the sensing layer was systematically investigated with respect to the analytical performance of the system. In its optimal configuration, the biosensor demonstrated (a) a sensitivity of 6.1 +/- 3 nA mM-1 dopamine (DA), (b) a linear response to DA (with a Michaelis-Menten constant of (4.50 +/- 0.02 mM), (c) good selectivity over ascorbic acid and uric acid, and (d) a high blocking capacity for ascorbic acid. (C) 2017 Elsevier B.V. All rights reserved.