Ionomer-coated electrodes and nanoelectrode ensembles as electrochemical environmental sensors: recent advances and prospects.

This Minireview focuses on recent advances in the use of ionomer-coated electrodes and nanoelectrode ensembles for the determination of redox ions at trace concentration level with special stress on applications for environmental monitoring. After an overview on the most recent developments of ionomer-coated electrodes, attention is directed towards their use for speciation analysis in environmental samples. In particular, some examples such as the selective determination of inorganic and metallorganic species of different toxicity and the redox state speciation of multiply charged ions are discussed. The second part of the Minireview deals with the development and electroanalytical use of a new kind of nanostructured electrode, named nanoelectrode ensembles, which are prepared by template synthesis within the pores of microporous guest membranes. Advantages, peculiarities, and limits of such devices are discussed together with perspectives for their use in electroanalytical sensing at trace and ultratrace concentration levels in environmental samples.