
Sensors for pH, Conductivity, Ion, DO and ORP Applications
Accurate pH, conductivity, ion concentration, dissolved oxygen and ORP measurements begin with the right sensor. METTLER TOLEDO combines a history of trusted technologies with innovation to guarantee performance and accuracy for any application.
Our variety of pH sensor offerings include built-in temperature probes, maintenance-free options and our Intelligent Sensor Management (ISM®) for enhancing data security and easy handling.
Please choose the Sensor Family that suits you best:
pH Sensor | Conductivity Sensor | Ion-Selective Electrode |
High quality sensors for general purposes as well as specialists designed for your application. | Robust conductivity sensors for precise determination over the whole conductivity range. | Quick and easy determination of the concentration of a variety of dissolved ions and gases. |
Dissolved Oxygen Sensor | ORP Sensor | LightEdition Sensor |
Optical and polarographic sensors for reliable determination of dissolved oxygen. | Accurate and reliable sensors that measure ORP (oxidation reduction potential). | pH, conductivity and dissolved oxygen sensors that are robust and budget-friendly. |
High quality sensors for general purposes as well as specialists designed for your application.
Robust conductivity sensors for precise determination over the whole conductivity range.
Quick and easy determination of the concentration of a variety of dissolved ions and gases.
Optical and polarographic sensors for reliable determination of dissolved oxygen.
Accurate and reliable sensors that measure ORP (oxidation reduction potential).
pH, conductivity and dissolved oxygen sensors that are robust and budget-friendly.

InLab® Sensors
Sensors for Any Application
The complete InLab® sensor portfolio covers the whole scope of applications. These range from routine measurements to specialist applications, be it in chemical, pharmaceutical, life science, food and beverage or a variety of other laboratory or production facilities.
To find your perfect match, visit our Sensor Selection Guide today.

Intelligent Sensor Management (ISM®)
Increased Data Security and Easy Handling
Our Intelligent Sensor Management (ISM®) is a sophisticated safety concept that leaves nothing to chance. With this technology, the instrument will automatically detect the connected sensor and will use the most up-to-date calibration data stored on the sensor.
Please choose the Sensor Family that suits you best:
pH Sensor | Conductivity Sensor | Ion-Selective Electrode |
High quality sensors for general purposes as well as specialists designed for your application. | Robust conductivity sensors for precise determination over the whole conductivity range. | Quick and easy determination of the concentration of a variety of dissolved ions and gases. |
Dissolved Oxygen Sensor | ORP Sensor | LightEdition Sensor |
Optical and polarographic sensors for reliable determination of dissolved oxygen. | Accurate and reliable sensors that measure ORP (oxidation reduction potential). | pH, conductivity and dissolved oxygen sensors that are robust and budget-friendly. |
High quality sensors for general purposes as well as specialists designed for your application.
Robust conductivity sensors for precise determination over the whole conductivity range.
Quick and easy determination of the concentration of a variety of dissolved ions and gases.
Optical and polarographic sensors for reliable determination of dissolved oxygen.
Accurate and reliable sensors that measure ORP (oxidation reduction potential).
pH, conductivity and dissolved oxygen sensors that are robust and budget-friendly.
Services

Explore our Services - Tailored to Fit your Equipment
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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FAQ
How do I find the right sensor for my application?
The manufacturing of high quality sensors with outstanding performance not only required technical skills and expertise but also a profound understanding of the various customer applications and their specific requirements. METTLER TOLEDO offers a comprehensive sensor portfolio that covers all of your application needs in pH, conductivity, ion, dissolved oxygen or ORP.
There are several ways to find the appropriate sensor
- Sensor Product Guide
- Sensor selection Table in the InLab sensor brochure (pages 34/35)
- Contact your local Mettler-Toledo representative or dealer
How do I store sensors correctly?
All user manuals come with the necessary information about the short and long term storage of the respective probe.
General tips for long term storage:
- pH and ORP sensors: with wetting cap filled with reference electrolyte (often 3 mol/L KCl); it is also possible to store the electrode in pH buffer 4 or in 0.1 mol/L HCl
- Ion selective sensors: dry
- Conductivity sensors: dry
- Polarographic DO sensors: with measuring module filled with electrolyte and with green protective cap mounted (dry) to protect from mechanical damage
- Galvanic DO sensors: with storage vial filled with 10% NaCl
- Optical DO sensors: in the calibration tube ensuring first that the sponge has been dampened with distilled water or keep the sensor in a beaker filled with distilled water
What is the minimum immersion depth of my sensor?
In general, sensors have to be immersed deep enough to have the membrane glass (1) and the diaphragm (2) completely covered by the solution.
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For some sensors, which are particularly designed for low volumes, the minimal immersion depths are as follows.
InLab® pH Sensors | minimal immersion depths: |
InLab® Semi-Micro: | 15 mm |
InLab® Solids (Pro): | 15 mm |
InLab® Viscous: | 14 mm |
InLab® Micro Pro: | 12 mm |
InLab® Redox Micro: | 10 mm |
InLab® Micro: | 7 mm |
InLab® NMR: | 7 mm |
InLab® Ultra-Micro: | 5 mm |
InLab® Nano: | 2 mm |
InLab® conductivity sensors: | |
InLab® 751-4 (Cond): | 16 mm |
InLab® 752-6: | 17 mm |
InLab® 730: | 30 mm |
Others: | |
InLab® 605: | 5 mm |
LE422: | 10 mm |
PerfectIon sensors: | 3 mm |
InLab® Reference Plus: | 20 mm |