Potentiometric sensing, which requires the use of ion-selective electrodes (ISEs) and reference electrodes, is used to determine electrochemically the concentration of target ions in a variety of chemical environments. In view of the need for more affordable and portable analytical devices with small sample volumes, all-solid-state ISEs and reference electrodes, in which a solid contact is used as ion-to-electron transducer, are highly desirable. This review describes how all-solid-state ISEs and reference electrodes function and presents important aspects that should be considered when designing such sensors for specific applications. Approaches to improving reproducibility, the stability of the emf response, lowering detection limits, and novel sensor designs are discussed along with specific examples from the recent literature. Emphasis is placed on the ion-to-electron transduction mechanism and the development of new solid contact materials, with a particular view to miniaturized ion-sensing devices with low cost and calibration-free sensing.
Bibliographical noteFunding Information:
This work was supported by the University of Minnesota Initiative for Renewable Energy and the Environment (IREE). J.H. thanks the Krogh family for support with a Lester C. and Joan M. Krogh Fellowship in Chemistry. We greatly appreciate the reviewers' most helpful suggestions.
© 2015 Elsevier B.V.
Copyright 2017 Elsevier B.V., All rights reserved.
- Calibration-free sensor
- Ion sensing
- Ion-selective electrode
- Ion-to-electron transduction
- Reference electrode
- Sensor miniaturization
- Solid contact