INVESTIGATION ON CARBON-FIBER MICROELECTR ODES .20. THE ELECTROCHEMICAL BEHAVIORS OF TOLUIDINE BLUE AT A CARBON-FIBER MICRODISK ELECTRODE

The electrochemical behaviour of toluidine blue (TB) at a carbon fiber microdisk electrode was studied. The effect of pH on the electrode pr ocess was investigated, and the number of H+ in the electrode process is 3 at the range of 1.5 similar to 3.7, 2 at pH3.7 similar to 5.5 or 1 and pH5.5 similar to 10.7, respectively. The apparent standard heter ogeneous electron transfer rate constant k degrees('), and E degrees(' ) of TB at various pH on the carbon fiber microdisk electrode were det ermined. The overall electrode reaction mechanism of toluidine blue wa s proposed. The adsorbability of TB on the electrode was studied, and the kinetics parameters in the control of adsorption process were dete rmined.