Highly reproducible solid contact ion selective electrodes: Emerging opportunities for potentiometry - A review

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Materials Science

Background:

• Solid contact ion-selective electrodes (SC-ISEs) are increasingly studied for ion sensing due to their potential for miniaturization, cost-effectiveness, and routine analysis in various sample types.
• Recent advancements focus on SC-ISEs with well-defined interfacial potentials, leading to improved electrode-to-electrode potential reproducibility, comparable to or exceeding liquid-contact ISEs.
• Reproducibility improvements stem from refining fabrication methods and incorporating novel control measures or modifiers within the ISE components.

Purpose of the Study:

• To provide an overview of methods for establishing and maintaining reproducible potentials in novel SC-ISEs.
• To highlight the challenges associated with reproducible potential generation during SC-ISE fabrication and utilization.
• To lay the groundwork for developing cost-effective, user-friendly, and potentially calibration-free potentiometric SC-ISEs.

Main Methods:

• Review of existing literature on SC-ISE fabrication techniques.
• Analysis of strategies for controlling interfacial potentials at membrane, solid contact, and substrate electrode interfaces.
• Examination of novel control measures and modifiers used in SC-ISE development.

Main Results:

• Identification of fabrication methods and control measures that enhance electrode-to-electrode potential reproducibility in SC-ISEs.
• Demonstration that some SC-ISEs achieve reproducibility levels rivaling or surpassing liquid-contact ISEs.
• Overview of challenges in achieving and sustaining stable potentials throughout the lifecycle of SC-ISEs.

Conclusions:

• Established methods and reviewed rules can guide the development of more reliable SC-ISEs.
• Further research into fabrication and interfacial control is crucial for advancing SC-ISE technology.
• The findings support the future development of practical, low-maintenance potentiometric sensors for diverse ion analysis applications.