In-line pH probe and in-line pH sensor for in-line pH measurement
In-Line ph Probe

In-Line pH Probes & Sensors

Reliable In-line pH Probes for Process & Water Applications

In-line pH sensors are analytical instruments designed for continuous measurement of pH in industrial processes. METTLER TOLEDO offers both analog and digital in-line pH sensors that are designed to measure accurately under harsh process conditions, in pure water and withstand high-temperature cleaning and sterilization. In-line pH probes with Intelligent Sensor Management (ISM) offer predictive diagnostics that help reduce maintenance efforts and ensure uptime for your in-line pH measurements.

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Accurate Performance in Harsh Environments

METTLER TOLEDO in-line pH probes offer a durable design suited to providing accurate pH readings in harsh chemical environments, including measurement in viscous media and at high temperatures.

Simplify Maintenance Through Intelligent Sensor Management

In-line pH sensors with ISM technology provide advanced diagnostics to improve sensor reliability. ISM helps avoid sensor failure and ensures maintenance is only performed when needed.

In-Line pH Sensors for Hygienic Environments

Select METTLER TOLEDO in-line pH sensors are designed to withstand steam sterilization, clean-in-place processes and autoclaving, making them well suited to pharmaceutical and food production.

Simplified Integration and Installation

Plug and Measure technology in ISM in-line pH sensors allow a sensor to be calibrated away from the process in a controlled environment. This allows for fast exchange of sensors in production.

pH and ORP in One Sensor

Redox measurement capabilities offered on select METTLER TOLEDO in-line pH probes allow for multiple measurements from a single sensor.

Sensors for Guaranteed Accuracy

Select METTLER TOLEDO in-line pH sensors offer a pressurized reference system for continuous self-cleaning of the diaphragm to ensure constant and accurate pH measurement.

In-Line pH Sensors for Pure Water Monitoring

METTLER TOLEDO offers in-line pH probes designed for pure water monitoring. They can detect pH in low conductivity waters provide accurate measurement in cycle chemistry or semiconductor UPW.

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What is an in-line pH sensor?

An in-line pH sensor, also called an in-line pH probe or in-line pH electrode, is an important tool to ensure proper in-line pH measurement and control for industrial processes. METTLER TOLEDO provides a wide range of different in-line pH sensors to meet your in-line pH control needs. Additionally, many of our in-line pH probes also offer a redox measurement.

How does an in-line pH sensor work?

A typical in-line pH sensor is made up of two separate electrodes built into one: a pH sensing electrode and a reference electrode. In the simplest terms, a pH sensing electrode uses a special pH sensing glass membrane. H+ ions permeate the membrane creating a charge. The potential between the two electrodes is the measurement of hydrogen ions in the solution, giving the measure of pH. An in-line pH sensor is then typically installed in a process application to provide continuous measurement.

How do I select the right pH probe for my application?

For optimal pH measurement, it is crucial to choose the right in-line pH probe for each measurement point. The most important criteria are: process chemical composition, homogeneity, temperature and pressure, pH range and container size (length and width restrictions). The choice of in-line pH probe is of particular importance for non-aqueous, low conductivity, protein-rich and viscous samples where general-purpose glass electrodes are subject to various sources of error. The response time and accuracy of an in-line pH probe is dependent on a number of factors. Measurements at extreme pH values and temperatures or low conductivity may take longer than those of aqueous solutions at room temperature with a neutral pH value.

How do I store an in-line pH sensor?

METTLER TOLEDO in-line pH sensors should always be stored in reference electrolyte. This allows immediate use of the in-line pH sensor when needed, and ensures a short response time. When stored dry for long periods, many in-line pH sensors must be reactivated by soaking for several hours before installation in order to get the optimal measuring results. If these measures are not sufficient, the electrode may be made functional by treating it with a special reactivation solution followed by subsequent conditioning in the reference electrolyte. Do not store an in-line pH sensor in distilled water, as this will cause the pH sensor to have a longer response time.

What is the shelf life of an in-line pH probe?

If an in-line pH sensor is stored at normal room temperature with its original storage cap and solution in place on the end of the electrode, it can last well over a year with no degradation in performance. If the storage solution is allowed to dry or leaks out due to storage at high temperatures, freezing or other causes, the life of the probe may be reduced significantly.

What in-line pH sensors are in METTLER TOLEDO's portfolio?

METTLER TOLEDO has a wide range of in-line pH sensors including:

  • The InPro 2000 family of refillable in-line pH sensors.
  • The InPro 3100 family of in-line pH sensors for biopharma and food and beverage production. 
  • The InPro 3250 family of pre-pressurized, liquid-filled in-line pH sensors that meet the needs of a wide range of industries.
  • The InPro 3300 non-glass, ISFET in-line pH sensor.
  • The InPro 4010 in-line pH Sensor that uses a polymer electrolyte and is ideal for wastewater applications.
  • The InPro 4260 and InPro 4281 families of in-line pH sensor for highly demanding chemical applications.
  • The InPro 4550 and InPro 4501 family with a polymer body for chemical and wastewater applications.
  • The InPro 4800 and In Pro 4881 pH sensors that are designed for strong resistance to oxidizing media, solvents, or sticky contaminants.
  • The InPro 4850i in-line pH sensor for chlor-alkali processes.
  • The pHure sensor and pHure sensor LE for in-line pH measurement in pure water applications.