Modification of a glassy carbon (GC) electrode surface by means of a thin film of zinc pentacyanonitrosylferrate (ZnPCNF) using electrochemical procedures is described and the modifier formation pathway is explained. Cyclic voltammetry of the modified electrode shows one pair of peaks with a surface-confined characteristic in 0.5 M KNO3 as supporting electrolyte. The effect of different alkali metal cations and some anions in the supporting electrolyte on the electrochemical behavior of the modified electrode was studied. The peak potential and peak current vary with different alkali metal cations, but anions such as NO3-, Cl-, CH3COO-, H2PO4-/HPO42- and SO42-in 0.5 M concentration have no effect on the peak potential and peak current. The response of the modified electrode is not affected by pH within a range 1-10. The transfer coefficient (alpha), charge transfer rate constant (k(s)) and diffusion coefficient of different alkali metal cations in the ZnPCNF film were determined. Catalytic ability of the modified electrode for the oxidation of hydrazine on the electrode was demonstrated by cyclic voltammetry, rotating disk electrode (RDE) voltammetry, chronoamperometry and chronocoulometry. (c) 2005 Elsevier B.V. All rights reserved.