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How to Calibrate an Electrode

An electrode is a glass sensor that measures the concentration of hydrogen ions in a solution. The concentration of hydrogen ions -- also known as the pH -- is important because it determines the acidity of a solution. To ensure accurate readings, an electrode must be calibrated before use. Most laboratories calibrate their electrodes once a day, but some require calibration before every experiment. While the specific steps required to calibrate an electrode vary slightly depending on the model, the overall process of calibration is similar for each one.

Things You'll Need

3 beakers
3 buffer solutions with pH values of 4.0, 7.0 and 10.0
Deionized water
Scientific wipes

Instructions

- 1
  Set-up the buffers. Take three clean, dry beakers and place them on a stable, level surface. Fill the first beaker with the buffer solution with a pH of 7.0, the second with the pH 4.0 solution and the third with the pH 10.0 solution.
- 2
  Measure the pH of the first buffer. Turn on the electrode and place the tip of the sensor in the solution with a pH of 7.0. Press the button that says "calibrate" (or simple "cal") and wait until the meter reads exactly "7.0."
- 3
  Remove the electrode from the solution. Rinse it thoroughly with the deionized water and wipe it dry with a scientific wipe.
- 4
  Measure the pH of the second and third solutions with the same procedure that was used for the first solution. Be sure to clean the electrode with the deionized water and scientific wipe between solutions.

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