Electropolymerization of 3-amino-5-mercapto-1,2,4-triazole on glassy carbon electrode and its electrocatalytic activity towards uric acid

This paper describes the electropolymerization of 3-amino-5-mercapto-1,2,4-triazole (AMTa) on glassy carbon electrode (GCE) and the electrocatalytic activity of the resulting polymer film towards uric acid (UA) at physiological pH. The electropolymerization of AMTa was performed by potentiodynamic method in 0.1 M H2SO4. The electropolymerized AMTa (p-AMTa) film was characterized by attenuated total reflectance FT-IR (ATR-FT-IR) spectroscopy, cyclic voltammetry (CV) and impedance spectroscopy. The p-AMT film showed a redox wave around 0.34 V in the absence of monomer in 0.1 M H2SO4. The surface coverage of the p-AMT film was estimated by integrating the area under the oxidation wave and it was found to be 6.1 x 10(-10) mol cm(-2), suggesting the formation of nanostructured film on GCE. The impedance measurements indicate that the p-AMTa film deposited by 15 cycles showed higher conductivity than the films deposited by 30 and 50 cycles. The electrocatalytic activity of the p-AMTa film was examined by studying the oxidation of UA. It dramatically enhanced UA oxidation current and shifted its potential towards less positive potential when compared to bare GCE. In contrast to thiadiazole based polymer films, the triazole based p-AMT film showed higher oxidation current for UA. The current response of UA was increased linearly while increasing the concentration from 1 mu M to 10 mu M and a detection limit was found to be 3.57 x 10(-8) M for UA (S/N = 3) by DPV method. (C) 2011 Elsevier Ltd. All rights reserved.