PERMEABILITY CONTROLLABLE OVEROXIDISED POLYPYRROLE FILM-MODIFIED GLASSY-CARBON ELECTRODES

A voltammetric study on overoxidised polypyrrole (PPy) film modified electrodes is reported. These electrodes show permselective and accumulative properties towards cationic dopamine (DA). The exclusion of anionic ascorbate offers substantial improvement in the selectivity of DA determination. Differences in voltammetric responses of DA and ascorbate are attributed to the charge and porosity of the film. The volume of doping ions used for PPy preparation takes an important role in the film permeability. Other factors such as film thickness and preconcentration time are also investigated.