pH Meter: Calibration

Calibrating the pH Meter

— Do not turn off the pH meters, they should always be left on.–
— Never touch the tip of the pH probe.–
— The pH probe should always be submerged in a solution, either storage buffer or a calibration solution.

  1. Record date, time, project, name(s), and meter number in log book.
  2. Change all three calibration buffers and reference solution, unless changed earlier the same day. Record buffer change (or not) in log book.
  3. Record pH of each buffer in log book (calibrated at pH…).
  4. Press speed then 8.
  5. Press no to enter standby mode.
  6. Press no to operator menu.
  7. Press yes to calibrate.
  8. Enter 3 for the number of buffers.
  9. Press no to automatic calibration.
  10. Rinse probe with distilled water into waste beaker and submerge in first buffer solution, 4.01.
  11. Press yes to probe in first buffer solution.
  12. Meter will display “not ready” wait until asks, “Calibrate at 4.01?” press yes.
  13. Remove probe and rinse with distilled water into waste beaker, submerge probe in second buffer solution, 7.00.
  14. Press yes to probe in second buffer solution.
  15. Meter will display “not ready” wait until asks, “Calibrate at 7.00?” press yes.
  16. Remove probe and rinse with distilled water into waste beaker, submerge probe in third buffer solution, 10.01.
  17. Press yes to probe in third buffer solution.
  18. Meter will display “not ready” wait until asks, “Calibrate at 10.01?” press yes.
  19. The meter will then display “Slope” followed by a number. Record this number in the pH log. Then press yes to continue.
  20. Rinse probe with distilled water into waste beaker, then submerge probe in 7.00 reference solution.
  21. Press yes to measure pH.
  22. Wait for meter to display “ready”, then record meter reading for reference solution in log book.
  23. Rinse probe with distilled water into waste beaker between measurements. Wait for meter to display “ready” before recording pH values.
  24. Record sites, pH values and notes in log book.
  25. Store electrode in closed vial containing electrode storage solution.