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For the first time, a single-piece, all-solid-state ion-selective electrode was fabricated with carbon black supporting platinum nanoparticles (PtNPs-CB) and a polymeric membrane. The PtNPs-CB, as an intermediate layer, was drop-casted directly on the solid substrate, and then an ionophore-doped solvent polymeric membrane was added in order to form a sensor. The performance of the newly developed electrodes was evaluated on the basis of potassium and nitrate ions. The stability of the electrical potential for the electrodes was examined by performing current-reversal chronopotentiometry, and the influence of the interfacial water film was assessed by the potentiometric aqueous-layer test. Fabricated potassium- and nitrate-selective electrodes displayed a Nernstian slope and several outstanding properties such as high long-term potential stability, potential repeatability, and reproducibility.

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A platinum nanoparticles (PtNPs) layer is used for the first time as an ion-to-electron transducer in a solid-state ion-selective electrode (SC-ISE). The electrode was prepared by adding the PtNPs as an intermediate layer between the ionophore-doped solvent polymeric membrane and the electrical conductor. The PtNPs layer was characterized by high resolution transmission electron microscopy, selected area electron diffraction and X-ray photoelectron spectroscopy. The stability of the electrical potential of the new solid-contact electrode was examined by performing current-reversal chronopotentiometry while the influence of the interfacial water film was assessed by the potentiometric aqueous-layer test. The performance of the new electrode was evaluated by determining K(+). The new electrode presented a Nernstian slope, a very good reproducibility of the standard potential values and a small potential drift.

Electrochemical impedance spectroscopy (EIS) is a powerful tool for the analysis of various electrochemical systems because it allows the separation and characterization of individual kinetic processes. In this paper we investigate whether changes in the EIS characteristics can be used to distinguish between solid-state ISE membrane that have been subjected to physical damage, biofouling or leaching of active components. We conclude that with these relatively simple electronic measurements, we can effectively evaluate the functionality of the ISE membrane; i.e. we can predict whether the sensors are fully functional, in need for calibration or are completely non-functional. We believe this could form the basis of a simple but effective diagnostic tool for probing the condition of remotely deployed ISEs in widely distributed chemo-sensor networks (e.g. for environmental monitoring) and for enhancing the reliability of these devices. Our ultimate goal is to implement such tools in place of conventional approaches to ISE testing like calibration with standard solutions, which require the integration of complex and costly fluidics.