Luminescent sensor molecules based on coordinated metals: A review of recent developments

Characterization of perfluorosulfonic acid polymer coated enzyme electrodes and a miniaturized integrated potentiostat for glucose analysis in whole blood.

Coordination chemistry in two dimensions: chemically modified electrodes

Electrochemical nanoarchitectonics and layer-by-layer assembly: From basics to future

After a long history and conflicting views, solid-contact (SC) solvent polymeric membrane ion-selective electrodes (ISEs) emerged as reliable potentometric-sensing devices with unique advantages. From the large variety of proposed SCs inherently conductive polymers emerged as the materials of choice. In our view, the most attractive feature of SC ISEs is their compatibility with thin- and thick-film microfabrication technologies that can provide cheap, mass-produced sensors and sensor arrays that can be integrated with the measuring, data acquisition, and control electronics in a straightforward way. However, despite the impressive properties of certain SC electrodes and their potential advantages, they remained primarily in the research laboratories. To make the jump from the research laboratories into commercial devices, it would be essential to prove that miniaturized SC ISEs can indeed match or surpass the performance characteristics of the conventional, liquid-contact macroelectrodes. In addition, it would be important to settle on the quality control criteria and testing protocols for assessing the performance characteristics of SC electrodes. It could help in interpreting the sometimes-inconsistent experimental data. Once cheap, miniaturized, SC ISEs will mach the performance characteristics of macroscopic-size electrodes, it is expected to have an important impact in a variety of applications requiring robust, maintenance-free, or single-use ISEs, e.g., in homecare or bedside diagnostics, environmental analysis, and quality control assessment. In addition, reliable SC ISEs are expected to revitalize the field of ion-selective field effect transistors and open new possibilities in combination with nanowire-based devices.

Quality control criteria for solid-contact, solvent polymeric membrane ion-selective electrodes

Donnees theoriques confirmees par des etudes en presence de differents couples redox incorpores dans le revetement de Nafion. Cas de [Ru (NH 3 ) 5 Cl] Cl 2 et [Os (bpy) 3 ] I 2 , (avec bpy=bipyridine-2,2'), en particulier

Influence of supporting electrolyte concentration and composition on formal potentials and entropies of redox couples incorporated in Nafion coatings on electrodes

Permselectivities of coatings and membranes prepared from polyanionic Nafion and from a new type of polycationic copolymer were evaluated by two methods. (i) Electroactive couples incorporated in coatings on graphite electrode surfaces served as redox probes whose apparent formal potentials changed as the concentration of supporting electrolyte was varied. The magnitude of those changes allowed the permselectivities of the coating to be surmised. (ii) Thicker layers of the polyelectrolytes were used as membranes to separate supporting electrolyte solutions of differing concentrations. The potential difference between reference electrodes placed on either side of the membrane allowed the permselectivities of the membranes to be judged. Both of the methods indicated nearly ideal permselectivity of Nafion coatings and membranes at supporting electrolyte concentrations below ca. 2 M. Ideal permselectivity continued to be registered for a Nafion membranes by the redox probe method even after the membrane had been punctured so that the bulk cation transference number was far from unity. For the polycationic copolymer, both methods indicated increasing deviations from ideal anion permselectivity as the concentration of the supporting electrolyte was increased. Interpretations and some consequences of the observations are presented.

Permselectivities of polyelectrolyte electrode coatings as inferred from measurements with incorporated redox probes or concentration cells

Apparent formal potentials are measured for Os(bpy) 3 3+/2+ exchanged in Nafion films on electrodes The apparent formal potentials in the films are compared with the formal potential for Os(bpy) 3 3+ / 2+ in solution using a description that assumes Os(bpy) 3 2+ and Os(bpy) 3 3+ equilibrate with sodium ions in the bathing electrolyte solution Good agreement is obtained between the experimentally determined values of the apparent formal potentials and the values expected using the equilibrium model Apparent reaction entropies are also measured for Os(bpy) 3 3+ / 2+ exchanged in Nafion

Thermodynamic relationships important for interpreting apparent formal potentials and apparent reaction entropies of redox couples in permselective media

Jody Redepenning

Papers

Influence of supporting electrolyte concentration and composition on formal potentials and entropies of redox couples incorporated in Nafion coatings on electrodes

Permselectivities of polyelectrolyte electrode coatings as inferred from measurements with incorporated redox probes or concentration cells

Thermodynamic relationships important for interpreting apparent formal potentials and apparent reaction entropies of redox couples in permselective media