How to calibrate a pH Electrode or pH probe?

How to calibrate a pH Electrode?

You calibrate a pH electrode or pH probe with pH buffer solution, also known as pH calibration solution. This is a special pH reference solution designed to calibrate pH meters and pH electrodes. A pH calibration buffer will have a fix pH point. Calibration is all about making sure that our pH meter or pH electrode will measure the exact same pH level as our pH buffer solution after calibration.

PH Calibration Solution for pH Electrode
A pH electrode is always connected to a pH monitor, pH meter or other controller that measures the signal coming from the pH electrode. Each system will have its own method of calibration and each system will have its preferred pH calibration solution needed for a correct calibration. So before you start, make sure you read the manual of your system, find out exactly what type of pH buffer you need and make sure you follow the procedure step by step. 

Step by step calibration of a pH electrode

This is a general step by step guide on how you can calibrate your pH electrode or pH probe. Please keep in mind that calibration procedures are different based on the model or brand that you are using. But in general we can follow these steps to correctly calibrate your pH electrode.

  1. Make sure you have the correct pH buffer and that it is fresh! 
  2. Prepare 1 cup with the new pH buffer
  3. Prepare 1 cup with clean water
  4. Prepare a piece of kitchen paper or toilet paper to absorb droplets
  5. Start the calibration procedure on your pH device
  6. Enter the pH electrode into the pH buffer and stir gently. Wait for 10 seconds and stir gently again. Wait for another 10 seconds or until the measurement has completely stabilized. 
  7. Confirm the measurement on your pH device.
  8. Repeat the steps with another pH buffer if your system supports double pH points. (clean your electrode in between with the clean water and absorbing paper) 

Never re-use your pH calibration buffer and store your pH electrode in KCl Storage Solution for pH meters when you are not using it.