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pH/ORP Sensors

With decades of experience providing pH/ORP sensors, METTLER TOLDEO offers state of the art solutions for pH/ORP analysis. pH can be described as a measurement of the relative acidity of a solution.  Oxidation reduction potential (ORP) is the measurement of the oxidative state of the solution.  The accurate measurement of pH/ORP is critical in optimizing processes.


Technical Features

In-line pH analyzers provide accurate process pH measurements in a wide range of environments, from ultrapure water to hygienic measurement in a bioreactor to dirty chemical production. A pH analyzer consists of a sensor, transmitter and process adaption, combined to best suit your pH control needs. In-line pH sensors have several elements that are required for them to measure the pH of a solution. The most important part of an in-line pH probe is the end which is in contact with the solution. The glass tip is a type of membrane on which a gel layer forms when the in-line pH sensor is in an aqueous solution. A similar gel layer also forms on the inside of the membrane glass.

METTLER TOLEDO‘s InPro 3100i, 3250i and 3253i family are pre-pressurized, liquid-filled, low-maintenance temperature, pH and ORP sensors for in-line measurements in demanding applications. The durable design is well suited for harsh chemical process conditions or to meet the stringent demands of sterile biotech applications where CIP and SIP are used. These rugged electrodes lead the industry for fast and precise measurements, even after repeated autoclaving or sterilization cycles at 140°C (284°F). For pharmaceutical applications, the InPro 3100i sensor is the basic, economical pH/ORP sensor that is suitable for most applications whereas the InPro 3253i is the top of the line pH/ORP sensor.  The InPro 3250i sensor is designed for food & beverage applications.    

pH electrodes with ISM functionality allows Plug and Measure and advanced diagnostics.  ISM simplifies the installation, handling and maintenance of measurement equipment.  For more information see the Accessories section.


When considering pH/ORP sensor features the following attributes should be taken into account:

  • Accuracy: Accurate measurement of pH is crucial for many applications. METTLER TOLDEO’S sensors are designed for high precision and reliability.
  • Durability: the InPro series of pH sensors are resistant to harsh chemical environments, very durable and constructed for long-term use.
  • Temperature Compensation: pH levels can be influenced by temperature variations. METTLER’S TOLDEO’S Sensors with temperature compensation ensure accurate readings in different operating conditions.
  • Quick Response Time: A fast response time is important, especially in dynamic processes where pH levels can change rapidly.
  • Low Maintenance: Sensors with minimal maintenance that reduce downtime and operational costs.
  • Compatibility with Different Solutions: the pH sensors are versatile enough to work with a variety of solutions commonly found in Pharmaceutical and Chemical industries.
  • Ease of Calibration: Calibration is essential for accurate pH measurements. METTLER TOLDEO’S sensors are easy to calibrate and maintain calibration over time.
  • Digital Connectivity: METTLER TOLEDO pH analyzers and ORP analyzers that use digital Intelligent Sensor Management (ISM) technology provide integrated predictive diagnostics.
  • Long Sensor Life: Longevity is a key factor. The InPro sensors offer a longer lifespan that contributes to cost-effectiveness and reduce the frequency of replacements.
  • Compliance with Industry Standards: All of our pH/ORP sensors comply with relevant industry standards and regulations.

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