SOP for pH Meter Calibration and Performing Measurements: Introduction, Requirements, and Procedure

Introduction of SOP for pH Meter Calibration and Performing Measurements

A standard operating procedure (SOP) for pH Meter Calibration and Performing Measurements is really useful since we have to face numerous tests in Research as well as Diagnostic laboratories. e.g. Buffer preparation, maintaining a buffer of culture media, pH of various body fluids (Pleural fluid, ascitic fluid, joint fluid), seminal fluid, etc.

SOP for pH Meter Calibration and Performing Measurement: Introduction, Requirements and Procedure
Fig. pH Meter Calibration Step

Performing 2 Points Calibration


  • Buffers of Ph 4.0. 7.0 And pH 10.0
  • Distilled water
  • Tissue paper roll
  • Test Sample
  • Potassium chloride


  1. First, select the buffer group (acidic or alkaline).
  2. Press the setup key until the setup icon appears on the display.
  3. Set temperature.
  4. Then select the buffer group using the up or down key select buffer group i.e. 1.
  5. Rinse the electrode with distilled water (D/W) and wipe with tissue paper and then place the electrode in pH 7.0 buffer and press cal.
  6. Press the read once the reading is stabilized and move on to the next buffer.
  7. Rinse the electrode with D/W  and wipe it with tissue paper and then place it in the next calibration buffer (e.g. pH 4.0 or 10) and press cal.
  8. Press read after the signal has stabilized.
  9. Relevant buffer value is displayed and stored.
  10. To finish calibration, return to sample measurement.
  11. Rinse the electrode and place it in the sample and press read.
  12. The signal stabilizes and displays freezes automatically, NA appears and the measurement icon disappears.
  13. Continue for other samples by rinsing the electrode with distilled water.


  • After completion of the task, leave the electrode in a potassium chloride solution.
  • The electrode is highly sensitive and thus handles it carefully.
  • Potassium chloride (KCl) should be 3 moles/liter.

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