CeO2 thin film electrode with a built-in electrochemically resetable oxidant for potentiometric stripping analysis

In this work a sol-gel derived CeO2 thin film, deposited on a glass substrate, was investigated for its potential use as a working electrode in potentiometric stripping analysis (PSA). The work was focused primarily on examination of the PSA performance of a CeO2 film electrode, where Ce(IV) can be exploited as a built-in chemical oxidant that can be electrochemically regenerated by the application of an appropriate anodic potential. The CeO2 thin film electrode exhibits a well-defined PSA response to Cu2+ in a solution, chosen as a convenient test cation. Its electrochemical behaviour in the presence of supporting electrolyte LiCl and Cu2+ was investigated by cyclic voltammetry. It was found that a very simple but crucial electrochemical pretreatment and conditioning of the CeO2 electrode was necessary for its good PSA performance. The parameters influencing the PSA signal, such as deposition potential and time, were studied. The linearity of the PSA signal versus Cu2+ concentration and its repeatability were also examined and found satisfactory. The suitability of the CeO2 thin film as a mercury free PSA electrode, with no need of an external oxidant, is discussed.