A reliable and accurate pH measurement is crucial to determine the efficiency of the process or quality of the products in industries such as agriculture, wastewater, hydroponic, food processing and etc. To ensure that your pH meter is providing you the reliable and accurate pH measures, users always have to have a good care on the pH meter. Let’s discuss how we should take a good care on the pH meter.

How a pH meter works

without going to full details, let’s see how a pH meter operates. A pH meter most commonly consists of two main parts as the electrode and the screen. Most pH meters has only one probe (some old pH meters may have two) that contains two different electrodes as glass electrode and reference electrode. Glass electrode has a silver alloy electrical wire submerged in Potassium Chloride and contains inside a special glass membrane made from special glass and salts of metals (sodium or calcium). The reference electrode has a silver alloy electrical wire suspended in potassium chloride in the same special glass membrane as the glass electrode, but it doesn’t have conductive coating as glass electrode. The screen can be a moving coil meter with a pointer that moves along the pH scale or digital meter with numeric ph reading.

When the probe is immersed in a solution, hydrogen ions will move towards the conductive glass electrode and replace some of the metal ions in the coating which creates a small voltage that can be picked by the reference electrode. Then this voltage is passed to the voltmeter which converts the signal in to a pH reading to be displayed on the screen of the pH meter.

Storing the electrodes

As the pH meters are very sensitive instruments, the probe always need to keep hydrated or else it may stop working. The special conductive glass coating is never left to dry. Either you can immerse the probe in a special storage solution or submerged in a falcon tube or covered with a special cap it comes with. Never user distilled or deionised water as continuous submersion in water can diffuse out the electrode, which will affect to the accuracy and reliability of the pH meter.

Calibrating the pH meter

For most accurate and reliable pH measurements, manufactures suggest the users to calibrate the pH meter each time a new set of measurements is carried out as it may help to identify the problems with electrodes. Calibration is a very easy task when you are following the manufactures’ instruction. Simply you need to immerse the probe in a solution of known pH and set the pH meter accordingly. Importantly keep the records of calibrations especially recording deviations and what corrective action was taken.

Cleaning the pH meter

It is important to clean the electrode of pH meter between uses to ensure the accuracy and reliability of its measurements. Once the measuring is over, take out the pH meter and rinse thoroughly with distilled or deionised water which is not good for immersing. Then dry it swiftly and gently and immerse the probe in the storage solution. If the probe is covered with dust or crystallised solution, it need to be professionally serviced. Always follow the manufactures’ instruction before starting to clean the pH meter.

Even though the users pay much care of the pH meter, the electrodes may come to a phase where it needs a replacement. If the pH measurements are taking longer response times or need frequent calibrations, the electrodes may need to replace.

Plus handle the pH meter care when transporting or carrying to avoid dropping to make sure it offers reliable and accurate pH measurements for your requirement.