Electrochemical Study of Chitosan Films Deposited on Gold Electrodes
Rebecca A. Zangmeister, J J. Park, G W. Rubloff, Michael J. Tarlov
We report the electrochemical characterization of chitosan films deposited on gold electrodes. Cyclic voltammetry was used to characterize the deposition and electroactivity of chitosan coated gold electrodes. Chitosan films were found to deposit at a gold electrode due to a local increase in pH at potentials more negative than 1.5 V vs. Ag/AgCl, a potential associated with the hydrolysis of water. The chitosan films are electrochemically inactive, and similar background charging currents are observed at bare gold and chitosan coated electrodes. The chitosan films are permeable to both cationic [Ru(NH3)63+/2+] and anionic [Fe(CN)63-/4-] redox couples, but anionic complexes are retained in the chitosan film. Semiintegral analysis was used to examine adsorbed redox species at the chitosan coated electrode surface. Electrochemical parameters, including diffusion coefficients, for the redox probes at the chitosan modified electrodes are presented.
anion exchange, biosensing, chitosan, electrochemistry, ion diffusion