This guide to pH measurement is a must-have reference for people involved in analytical measurement roles that include pH. Written for people in process industries, the pH Theory Guide covers a wide range of theoretical and practical situations in regard to the measurement of pH. In this guide you will read about tools for pH measurement, maintenance of a pH probe, pH probe selection and handling, and much more.

pH Analyzer - Frequently Asked Questions (FAQ)
Refillable pH Probes and ORP Probes | Hygienic pH Probe for Sterile Applications | Durable pH Probe for Harsh Applications | Pure and Ultrapure Water pH Probes |
In applications where precise measurements are important, refillable pH and ORP probes deliver high accuracy and long lifetimes. | Sterilizable, hygienically designed pH and redox (ORP) sensors offering high measurement accuracy in pharmaceutical, biotech and food applications. | Specialized, highly durable pH and redox (ORP) probes designed to perform reliably under harsh conditions in chemical applications. | Pure water pH probes are in-line pH sensors for achieving optimal accuracy and resolution in pure and ultrapure waters. This type of pH sensor includes the pHure Sensor LE, a refillable pure water pH... |
Refillable electrolyte for longer sensor lifetime Ability to select application specific electrolyte Silver-ion trap prevents sulfide poisoning ISM diagnostics indicate maintenance timelines Available in pH and ORP/Redox models | Designed for regular SIP and CIP processes For use in bioreactors with high pressures Diagnostics help prevent batch interruptions Unique models for upside-down installation Liquid, gel and polymer reference electrolytes | For use in difficult industrial environments Withstands abrasive, sticky or oxidizing media Diagnostics help manage sensor cleaning efforts Titanium models prevent sensors from breaking Liquid, gel and polymer reference electrolytes | Designed for water treatment applications Free-flowing liquid electrolyte for reliability Eliminates need for flow bowl for high accuracy Plug and measure technology for fast set-up Available in pH and ORP/Redox models |
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ISFET pH Probe, Non-Glass Sensors | Portable pH Meter | Intelligent Sensor Management (ISM) Accessories | Single Use Sensors for Bag Manufacturers |
ISFET pH probes offer a non-glass solution for industries such as food or biotechnology, where safety and hygienic design are paramount. | Easy-to-use, portable pH meters for industrial applications. They offer high measurement accuracy in a robust, weatherproof design. | ISM accessories such as software or transmission solution allow you to take full advantage of ISM technology. | Single use sensors for measuring pH and dissolved oxygen in bioprocessing applications requiring single use bags. |
Unbreakable, solid-state ISFET technology FDA and 3-A compliant materials Hygienic design is EHEDG tested | One-handed operation and an intuitive interface Weatherproof and robust for demanding environments Rigorously drop tested to ensure durability Easy data management with 2,000 stored data points | Calibrate your sensors away from the process Monitor sensor history, diagnostics & inventory Easy system verification with sensor simulators Connect sensors to a computer or mobile | Designed for 1" Eldon James port disc Suitable for use in a wide range of applications Long-term measurement stability Ideal for welding to bag stock |
In applications where precise measurements are important, refillable pH and ORP probes deliver high accuracy and long lifetimes.
Sterilizable, hygienically designed pH and redox (ORP) sensors offering high measurement accuracy in pharmaceutical, biotech and food applications.
Specialized, highly durable pH and redox (ORP) probes designed to perform reliably under harsh conditions in chemical applications.
Pure water pH probes are in-line pH sensors for achieving optimal accuracy and resolution in pure and ultrapure waters. This type of pH sensor includes the pHure Sensor LE, a refillable pure water pH...
ISFET pH probes offer a non-glass solution for industries such as food or biotechnology, where safety and hygienic design are paramount.
Easy-to-use, portable pH meters for industrial applications. They offer high measurement accuracy in a robust, weatherproof design.
ISM accessories such as software or transmission solution allow you to take full advantage of ISM technology.
Single use sensors for measuring pH and dissolved oxygen in bioprocessing applications requiring single use bags.
Publications
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pH Theory Guide

pH Calibration Guide
This pH calibration guide walks you through the step-by-step process of how to calibrate a pH probe. Find information on the materials you need for extending the life of your pH sensors, and the process for calibrating in the field and in the maintenance shop.

pH & Dissolved Oxygen Accuracy Guide
This guide is designed to help you ensure you have consistent accuracy in your pH measurements. It covers topics related to precision and accuracy of a pH probe, requirements for a highly accurate pH sensor, and influencing factors that can give you errors for your overall pH measurement system.

Process Analytics Catalog
In the Process Analytics Catalog you will find more detailed specifications of many of our most popular models of pH sensors. Included are our probes for measuring the pH of pure water, our pH probes with Intelligent Sensor Management and our ORP probes. Complete your entire pH meter with a transmitter and housing for easy installation. Additionally, you will find sensors and analyzers for a wide range of other analytical parameters that we support.
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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.
Training & Consulting

Videos
How a pH Probe Works
This video shows the fundamentals of how a standard combined pH probe measures. You'll learn the key parts of the pH electrode, and see an overview of how the pH-sensitive membrane glass works in different solutions to measure different pH values.
How a pH Sensor Is Made
Get an overview of how METTLER TOLEDO makes thousands of InPro pH sensors per year in our factory in Urdorf, Switzerland. See how competence, precision and quality are critical to hand-crafting each of our glass pH electrodes.
Analog vs Digital pH Sensors in the Pharmaceutical Industry
Learn the benefits of digital pH probes in the process industries. This example in the pharmaceutical industry demonstrates the benefits of pre-calibrated digital sensors with ISM technology. Shifting to digital sensors can help achieve greater process reliability, easier pH sensor handling and can simplify your compliance processes.