Knight:pH meter/Calibration

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Contents

Overview

Some quick notes on how to calibrate our pH meter.

Materials

  • pH standard solution 4.0
  • pH standard solution 7.0
  • pH standard solution 10.0
  • 3 20mL beakers
  • 1 beaker to collect washes
  • Squirt bottle with distilled water
  • Kimwipes

Procedure

  1. Raise the electrode out of the storage buffer.
  2. Rinse with distilled water from a squirt bottle over a beaker used to collect washes.
    • Do not rinse the electrode into the soak beaker.
  3. Touch electrode gently with Kimwipe to remove excess fluid.
  4. Press the CAL key.
  5. Press the CLEAR key twice to remove existing calibration.
  6. Pour 1 inch of standard pH buffer 4 into small beaker.
  7. Immerse the tip of the electrode into beaker.
  8. Press the READ key.
  9. Wait until the Auto-Eye stops flashing. The pH meter should read 4.00.
  10. Rinse with distilled water from a squirt bottle over a beaker used to collect washes.
  11. Touch electrode gently with Kimwipe to remove excess fluid.
  12. Pour 1 inch of standard pH buffer 7 into small beaker.
  13. Immerse the tip of the electrode into beaker.
  14. Press the READ key.
  15. Wait until the Auto-Eye stops flashing. The pH meter should read 7.00.
  16. Rinse with distilled water from a squirt bottle over a beaker used to collect washes.
  17. Touch electrode gently with Kimwipe to remove excess fluid.
  18. Pour 1 inch of standard pH buffer 10 into small beaker.
  19. Immerse the tip of the electrode into beaker.
  20. Press the READ key.
  21. Wait until the Auto-Eye stops flashing. The pH meter should read 10.01.
  22. Press the CAL or EXIT key to exit the calibration mode.
  23. Rinse with distilled water from a squirt bottle over a beaker used to collect washes.
  24. Touch electrode gently with Kimwipe to remove excess fluid.

The pH meter is calibrated for measuring the pH of most buffers and solutions. For more exact measurements or to pH solutions with more extreme pH, you may need additional/alternate calibration buffers.

Notes

  • The electrodes of pH meters are both fragile and expensive. Be careful when immersing it to not hit it against the beaker.

References

  1. Beck Φ 300 Series operating manual http://www.beckmancoulter.com/Literature/BioResearch/511291AA.pdf [Manual]
  2. Kathy Barker. At the bench. Cold Spring Harbor, N.Y.: Cold Spring Harbor Laboratory Press, 2005. isbn:0879697083. [AtTheBench]

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