1Electroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz, I.R. Iran
2Electroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz, I.R. Iran
A thin film of epinephrine (EP) was electrochemically deposited on the surface of glassy carbon electrode previously activated in NaHCO3 solution. The cyclic voltammograms of the modified electrode indicate that the surface confined EP are strongly dependent on the solution pH, as expected for quinone/hydroquinone functionalities. The EP-modified glassy carbon electrode exhibited catalytic activity towards the electrooxidation of hydrazine, which appeared as a reduced overpotential especially in pH = 7.5. The diffusion coefficient of hydrazine was estimated using chronoamperometry. The catalytic rate constant, Kh, of the modified electrode for the oxidation of hydrazine was determined using the cyclic voltammograms recorded at low scan rates as well as the RDE voltammetric approach. It has been shown that the EP-modified electrode can be used as an amperometric sensor in the analysis of trace amount of hydrazine with high sensitivity and good limit of detection (0.83 mM). Amperometry by EP-modified electrode was used for determination of hydrazine in boiler feed water and the accuracy of the results was verified by comparison with those obtained from standard ASTM method.