Fe3+ ion sensing characteristics of polydiphenylamine-electrochemical and spectroelectrochemical analysis

Polydiphenylamine (PDPA) film was deposited on platinum/indium tin oxide coated glass (ITO) electrode in aqueous acidic medium and analyzed for the changes in redox characteristics in the presence of acidified iron (III) chloride (FeCl3). PDPA seems to capture Fe3+ ions and further transforms into Fe2+ ions through interaction with its redox binding sites, as confirmed through results from cyclic voltammetry and UV-vis spectroscopic studies. The redox behavior for the PDPA film modified with Fe3+ ions was evaluated through in situ UV-vis spectroelectrochemical studies. In situ studies demonstrate that PDPA is partially reduced in the presence of Fe3+ ions and the redox transformation was almost reversible. Modified PDPA film electrode showed Nernstian potential response for Fe3+/Fe2+ redox process and such modification is expected to be suitable for sensor applications.