Electrocatalytic oxidation of hydrazine using glassy carbon electrode modified with carbon nanotube and terpyridine manganese(II) complex

Here, we report a simple and extremely effective method to modify a glassy carbon (GC) electrode with carbon nanotubes (CNTs) and [Mn(CH3COO)(CH3OH)(2)(pyterpy)]ClO4, (pyterpy = 4'-(4-pyridyl)-2,2':6',2 ''-terpyridine) complex. The kinetics of the reaction between, the terpyridine manganese(II) complex, mediator and hydrazine has been characterized using cyclic voltammetry and rotating disk electrode voltammetry. The catalytic currents were proportional to the concentration of hydrazine giving rise to calibration curves characterized by two linear segments. The linear segment over the concentration range of 1.00 x 10(-3)-1.05 mM could be used with analytical purposes to determination of hydrazine with a detection limit of 0.50 mu M and a sensitivity of 0.038 mu A/mu M. The heterogeneous rate constant, k' for the oxidation of hydrazine at the surface of the modified electrode was determined by rotating disk electrode voltammetry using the Koutecky-Levich plot. The transfer coefficient (alpha) for electrocatalytic oxidation of hydrazine and the diffusion coefficient of this substance under the experimental conditions were also investigated. The resulting modified electrode retains its initial response for at least one month if stored dry in air. (C) 2010 Elsevier B.V. All rights reserved.