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How to Clean the Inside of a pH Electrode

A pH electrode is a device used to measure the acidity of a solution. It does by calculating the difference in potential between a sensing membrane ̵1; which varies with pH ̵1; and a reference electrode where potential is static. The difference in millivolts is then converted to pH and displayed on a small screen. To ensure an accurate reading, the pH electrode must regularly be cleaned.

Things You'll Need

Distilled water
Potassium Chloride solution

Instructions

- 1
  Remove the rubber plug from the side of the electrode.
- 2
  Remove the filling solution, potassium chloride (KCl), by turning the electrode upside down. Use a pipet to remove any excess.
- 3
  If crystals have formed inside the electrode, use a syringe to fill it with distilled water then place the electrode tip in hot tap water for 15 minutes or until the crystals have dissolved. Pour the distilled water out once this has happened.
- 4
  Refill the electrode with fresh KCl solution, replace plug and wash thoroughly with distilled water.
- 5
  Test a sample solution as you normally would. If the pH electrode is slow to respond, or you are suspicious of the result, repeat the cleaning procedure. You may need to do this more than once.

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