Ion Selective Measurements: Sensors

Appropriate sensor is fundamental to any measurement setup. Variety of different types and variants are available, depending on the measured quantities, sensor dimensions, as well as usage workflow, environment, and installation method. The vast majority of sensors listed below are just components of a larger measurement setup, and can therefore be satisfactorily used only with a compatible analyzer. Sensors for in-technology measurements should be installed inside our probes, ensuring their fixing and protection, and these connect to a terminal block. Variants for laboratory and portable usage are terminated with the appropriate connector. Sensors generally have the shortest lifetime of the entire setup, due to direct contact with the measured medium.

Ion selective electrodes


Ion selective electrodes are sensors designed for the measurement of specific chemical ions in a solution, both in laboratory and industrial applications.

Not all ISE sensors include a reference electrode - in its absence, a separate reference electrode must be used. For industrial applications, a suitable probe or flow-through unit must be used that allows at least two sensors to be installed.

The dimensions of the industrial version of these sensors (Ø12 x 115 mm) are suitable for probes SPO41, SPO42, SPR42, SVK42, PE G3/4D, SPO41ME or SPR41ME. A laboratory version of similar dimensions is also available, with a cable terminated with the appropriate connector according to the device used.

The ion-selective electrodes supplied with our devices are sourced from third-party suppliers. More detailed information and the current availability of the variant suitable for a specific device will be specified upon request.

TypeIonAlternative designation
07-35NO3- (Nitrate)20-31, 25-32 (combined)
11-35NH4+ (Ammonium)20-10, 25-10 (combined)
19-35K+ (Potassium)20-19, 25-19 (combined)
20-35Ca++ (Calcium)20-20
09-37F- (Fluoride)20-09, 25-09 (combined)
17-37Cl- (Chloride)20-17, 25-17 (combined)

Reference electrodes


For sensors that do not have an integrated reference electrode, separate reference electrodes are required – this is often the case with ion-selective electrodes. Since a pair of separate electrodes is then used, industrial applications will need a suitable probe or flow-through unit that allows at least two sensors to be installed.

Commonly supplied sensors for measuring pH and ORP have the required reference electrodes already integrated, so there is no need to supplement them with additional electrodes.

TypeSuitable forDimensions
RAE111Installation with SPO42, SPR42Ø12.2 x 115 mm
RAE111KInstallation with PB42V, PB43VØ12.2 x 57 mm
on requestLaboratory measurements (multiple options)typ. Ø12.2 (Ø18) x 115 (145) mm