Understanding ISE Measurements In Wastewater Process Monitoring

Analytic measuring technique provides a huge number of procedures to determine the concentrations of substances in an unknown sample, e.g. photometry, titration or mass spectrometry. One advantage of working with ion sensitive electrodes (ISE) is that it is possible to obtain meaningful data about individual substances using economical systems. Otherwise, this is only possible with much more expensive instrumentation. Ion sensitive electrodes are electrochemical sensors that can be used directly in the mg/L range and below. The YSI developments demonstrate that this measurement principle is also suitable for continuous online operation.

Analysis with ISE is among the so-called potentiometric procedures. This means the wanted signal occurs in the form of potentials, more precisely of potential differences, or voltages in mV.

An ion sensitive measuring system basically consists of the ISE reacting on a special ion type and a reference electrode that are jointly immersed in the sample to be measured.