Abstraet-A new type of Prussian blue analogue cobalt hexacyanoferrate (CHCF) fihn modified glass carbon and platinum electrodes is described. The thin film of the mod&r is introduced onto the electrode surface by electrodeposition of cobalt, which forms CHCF by subsequent scanning in NaAc-HAc buffer solution containing K, Fe(CN), . The amounts of the modifier on the electrode surface can be controlled by changing the time of the electrolysis and the concentration of Coz+ and Fe&N):-ions. In sodium chloride and potassium chloride solutions, the film exhibits nearly ideal reversible cyclic voltammetric behaviour at the potential of about +0.38 V (us see) on the electrode surface. Unlike the Prussian blue fihn modified electrodes, besides K+, NH:, Rb+, Cs+; Na+ can also transport through the 8lm during the electrode process. The ir, M&batter and KPS spectroscopic experimental results show that the redox couple is not Co(III)/Co(II) but Fe(III)/Fe(II). The iilm contains Na+ and K+ when the electrode is transported into NaCl and KC1 medium respectively. The influence of electrolyte and solvent on the electrochemical behaviour of the modified electrode has been examined. The moditied electrode exhibits excellent stability in aqueous media and in air. The film is shown to he electrochromic and the electrode process can he presented as follows: +c-MCo[Fe(CN),] . xH,O + M+ z+=== M,Cop(NzN)J * xHs0 (M = Na+, K+).
(bmrn) -