Getting a Grip on Drift: Pursuing Long–Term Stability of Ion–Selective Electrodes

Ions play a fundamental role in chemical and biological systems, governing processes essential to human health and agricultural productivity. In this context, solid–contact ion–selective electrodes (SC–ISEs) offer an effective means of measuring the concentration of key ions such as sodium (Na+) and potassium (K+). However, long–term implementation of ISEs is currently limited by variability in sensor performance and signal drift. This thesis aims to understand and mitigate these limitations in chip–based devices by investigating the influence of sensor design and material selection on performance and stability. In doing so, it challenges common assumptions about the properties required for sensor materials, and demonstrates that stable performance depends on the combined effect of multiple factors rather than a single design feature. By improving our understanding of the mechanisms underlying sensor stability, this research contributes to the development of more reliable and scalable ion-sensing technologies for healthcare, environmental monitoring, and agriculture.