▎ 摘　　要

A nanocomposite film is prepared by cyclic voltammetric deposition of electroreduced graphene oxide (ERGO) and polythionine (PTH) on a glassy carbon (GC) electrode. The electrodeposition of ERGO-PTH film is also investigated via the electrochemical quartz crystal microbalance (EQCM) method for more in-depth understanding of the process. The ERGO-PTH nanocomposite film is applied as transducer for facilitated electrocatalytic oxidation of NADH and for the construction of dehydrogenase-based amperometric biosensor. Under optimum conditions, the amperometric detection of NADH provides a wide linear detection range (0.01-3.9 mM), a high sensitivity (143 mu A mM(-1) cm(-2)) and a low limit of detection (LOD = 0.1 mu M, S/N = 3). With alcohol dehydrogenase (ADH) as a model, we obtain a linear amperometric response of the ADH-modified ERGO-PTH/GC electrode to ethanol concentration from 0.05 to 1.0 mM, a sensitivity of 2.8 mu A mM(-1) cm(-2), and a LOD of 0.3 mu M (S/N = 3). (C) 2013 Elsevier B.V. All rights reserved.