A pH sensor is a scientific device that detects the alkalinity and acidity of liquids such as water. It is a vital instrument utilised in various sectors, including power plants, pharmaceuticals, food and beverage, primaries, chemicals, oil and gas, and wastewater. When it comes to assessing water quality, various durable pH sensor perform differently. As a result, it is critical to understand the many variants available so that you may choose the proper pH applications that could meet your needs. As a result, you will discover all you need to know about pH sensor in this post.


What Kinds of pH Sensors Are There?

There are four primary kinds of pH sensors to choose from, which are as follows:

pH Sensors in Combination

This is the most popular sensor for a reason; it serves as the basis for process sensors and lab sensors. It also comes with two separate electrodes: a measurement electrode and a reference electrode. The two sensors detect the minute electrical difference between the two electrodes.

Differential pH Sensors

A differential pH sensor is a heavy-duty sensor since it has an extra electrode that helps avoid reference fouling. Instead of combination pH sensors, different pH sensors feature three electrodes and operate differently. The first two electrodes are similar to those in combination sensors, whereas the third is a metallic ground conductor.

pH Sensors for Laboratories

They are small sensors with coupled pH sensor technology that are suited for light applications, environmental sampling, and pool monitoring. One benefit is that they may be tailored to the specific application knowledge needed. They are divided into three categories: basic, advanced, and research, with pH 1000, 2000, and 3000, respectively.

Process pH Sensors

Process pH sensors have a longer lifespan, using better combination sensor technology. Their basic sensors include process connections, making them suitable for continuous pH monitoring. Because the sensors are very durable, they may be mounted directly to a pipe or placed in a tank.


What Material Is The Ph Sensor Constructed Of?

The exterior enclosure is distinguishable when comparing consumer-grade, lab-grade, and industrial sensors. The consumer and lab-grade sensors feature polycarbonate and Ultem exteriors, respectively, while the industrial-grade sensor has a CPVC enclosure. The distinction is based on strength, temperature resistance, and chemical resistance. As the price and quality of the sensor increase, so do the materials and their ability to withstand harsh situations.


Following that, the glass sensor tip, or sensing material, is available in various grades and coatings to accommodate temperature and application variations. Higher quality pH sensor materials allow for greater pH ranges and varying sensitivities to typical water constituents that might alter pH readings, such as salt or chlorine. Furthermore, some sensors include ISFET (ion-specific field-effect transistor) electrodes, which are an alternative to glass and do not need continuous moisture preservation.


Finally, the inner chemicals in the sensors and the junctions that divide them from the outside world are made from various materials. However, most sensors use silver chloride or potassium chloride and some ceramic junctions for application. Increasing the toughness of these materials or adding additional connections would be appropriate for harsher applications and polluted settings.


The Benefits And Drawbacks Of Ph Sensors

This section discusses the benefits and drawbacks of pH sensors.



  • It aids in determining the quantity of primary and acidic components in any solution.
  • Because pH metres are exceedingly accurate thanks to pH sensors, they deliver exact pH readings.
  • The metres immediately provide numerical pH readings.
  • Used in a variety of applications, including stain removal, pool maintenance, and cheese making.
  • It is the easiest and fastest way to measure pH.



  • Expensive
  • Breakage risk owing to fragile glass electrodes
  • pH calibration probability due to carbon dioxide absorption and temperature effect
  • The pH is often calibrated.
  • Possibility of process stoppage owing to electrode membrane deposits
  • It must be calibrated using a specific buffer solution.


How Should The Ph Sensor Be Cared For?

A pH electrode must be maintained regularly if the pH sensor remains in excellent working order. Oily coating, blockage or fouling of the reference contact, malfunction or fracture of the PH bulb, and short electrode life owing to reference poisoning are all common concerns that may damage the electrode if not properly maintained.


Consider employing a non-porous reference junction sensor if the electrodes are typically covered with oil or other contaminants. Adopting automatic cleaning solutions for electrodes might further minimise your maintenance requirements. A non-porous electrode may be employed to solve the issue if the reference junction is often blocked or fouled. When your pH bulb breaks after coming into contact with sewage, you could preserve it with a bulb protection. The use of non-porous electrodes may help to prevent the issue of reference poisoning.



Suppose you need a pH sensor for a specific application. In that case, it is crucial to check the specification papers to guarantee that the sensor materials will not conflict with your pH readings. However, you wouldn’t have to be concerned with such minute details. Just determine your application’s pH and temperature ranges to select the appropriate type and grade of pH sensor.