Modification of electrodes with nanostructured functionalized thiadiazole polymer film and its application to the determination of ascorbic acid

We report the electropolymerization of 2-amino-1,3,4-thiadiazole (ATD) on glassy carbon (GC) and indium tin oxide (ITO) electrodes in 0.10 M H2SO4. The electropolymerized ATD (p-ATD) film was characterized by cyclic voltammetry, attenuated total reflectance (ATR)-FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The AFM image showed that the p-ATD formed a spherical-like structure with a thickness of 25 nm. XPS of the p-ATD film showed binding energies at 398.7, 400.3 and 401.3 eV in the N 1s region corresponding to -N=, -NH- and -N+H-, respectively, and at 285.5 and 287.0 eV in the C 1s region corresponding to C-N and C=N, respectively. The appearance of binding energies at 285.5 and 287.0 eV confirmed that the p-ATD film proceeded via C-N and C=N linkages and not via C-C or C=C linkages. The p-ATD film deposited on the GC electrode was successfully used for the determination of ascorbic acid (AA) at physiological pH. The amperometric current was increased linearly from 7.5 x 10(-8) to 2.0 x 10(-5), and the detection limit was found to be 0.28 nM (S/N=3). (C) 2009 Elsevier Ltd. All rights reserved.