Ion-Selective Electrode: For a Wide Range of ISE Applications

Ion-Selective Electrode

Combined and Half-Cells ISE for Reliable Ion Measurement


pH Meters

To fit your electrochemistry system needs, we offer a variety of benchtop and portable meters that are professional and durable. Our portfolio offers products designed for compliance, routine measurements or anyone working on a tight budget.

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METTLER TOLEDO offers a comprehensive range of top quality buffers, standards, electrolytes, cleaning and verification solutions for determination of pH, conductivity, ion concentration, ORP and dissolved oxygen.All solutions are available in small volume bottles either in packs or single and single use sachets.

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We offer different service packages depending on your needs. These range from professional on-site installation and configuration to documented proof of compliancy. If full coverage beyond initial warranty is desired, we offer an extended care package in the form of preventive maintenance and repair.

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Products and Specs


Product Brochures

InLab® Sensors
The manufacturing of high quality sensors with outstanding performance not only requires technical skills and expertise but also a profound understand...


Fluoride Ion Selective Electrode
Download a free copy of the Fluoride Ion Selective Electrode Application Guide and get more information about theory, principle and calibration for th...
Ion Selective Electrode Guide
Receive a free copy of the Ion Selective Electrode Guide and get useful tips and hints for selected ISE applications in various industrial segments. L...


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We support and service your measurement equipment through its entire life-cycle, from installation to preventive maintenance and calibration to equipment repair.

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How to store Ion Selective Electrodes correctly?

All user manuals come with the necessary information about the short and long term storage of the respective sensor. Generally Ion Selective Electrodes should be stored dry for long term storage.

What response time is reasonable for an ion selective electrode?

The response time depends on the type of ion as well as its concentration.

Whereas the relatively fast sensors for Na+ and F- feature response times of 1-3 minutes at higher concentrations, the response time increases to 5-10 minutes when measuring in the range of the lower detection limits.

The size of an ion has an important impact on the speed of a measurement. That is why most of the other ions take longer to be measured. Analysis of heavy metals such as Cu2+ or Cd2+ can even take 20-30 minutes when performed near the lower detection limit.

A gentle and constant stirring in ion measurement is crucial for achieving a stable signal as fast as possible. Stabilization is reached faster, when moving from a lower concentration to a higher one than going the inverse way. Therefore, it is recommended to always start with the lowest concentration when calibrating and measuring.

What is the detection limit of an ion selective electrode?

The potential of the sensor is measured at many different concentrations of the ion of interest. One draws a curve of these mV signals against the concentration (logarithmic). Normally, it is S-shaped: rather flat at very high and at very low concentrations, almost linear in-between. The specified detection limits are defined by the range in which the behavior is more or less linear. To make an ISE usable for a different range, one would have to change the membrane surface (larger for lower concentrations) or use a different ion-selective substance in the membrane.

What is the average lifetime of sodium ISE?

A sodium selective electrode is a glass electrode very similar to a pH electrode. pH glass electrodes show a negligible alkali error, and amplification of the "alkali error" leads to sodium selective electrodes which respond only to changes in the sodium ion concentration at pH values above 7. Therefore the lifetime of a sodium ISE is similar to the lifetime of a pH electrode, and is influenced by a number of factors (e.g. elevated temperatures, extreme pH values, etc.).

Join the GEP eLearning Program
Know the Risk of Your pH Measurement
Ion Selective Electrode Guide – Theory and Practice
pH Theorie Guide
How to Measure pH in Small Samples
pH Toolbox for Life Sciences
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