What Causes pH Sensor Drift?
One major cause is changes to the glass pH-sensitive membrane. Over time, the glass can become coated, chemically attacked, dehydrated, or otherwise altered by the process medium. These changes can slow the sensor response, shift the zero point, or reduce measurement stability.
The reference electrode is just as important. It must provide a stable reference potential for the measurement. If the reference junction becomes clogged, the electrolyte level drops, or the reference system becomes contaminated, the measured signal can shift and become unstable.
