SOP for Operation and Calibration of pH Meter Model- Hi 2211

To lay down a procedure for the Operation and Calibration of the pH Meter (Model-HI2211)

This procedure applies to the pharmaceutical manufacturing facilities of XYZ Limited.

Execution: Chemist and above – QC department.
Checking : Asst. Manager and above – QC department

  • Switch ‘ON’ the mains.
  • Clean the electrode with distilled water and soak it with tissue paper, do not wipe the electrode.
  • The display shows a ‘measured value’ with temperature.
  • Immerse the electrode in the test solution.
  • After a while, the unit will display the temperature and the measured value of the solution
  • On completion remove the electrode from the test solution.
  • Rinse the electrode with distilled water and dry it with tissue paper.
  • Immerse the electrode in 4 M KCl after the measurement.
  • Switch “OFF” the instrument.
  • Switch “OFF” the mains.

  • Connect the combination of the pH electrode and the temperature probe to the input socket.
  • Switch ON the mains
  • Switch ON the instrument.
  • Wash the electrode already dipped in KCl solution with distilled water
  • Dip the electrode and temperature probe in a 7.0 pH buffer.
  • Press CAL. The “7.00” and “BUF” messages will appear and the “7.00” buffer will be displayed on the Secondary LCD.
  • If necessary press the arrow key to select a different Buffer value.
  • The “6” symbol will blink on LCD until the reading is stable.
  • When reading is stable and close to the selected buffer, the "READY” message will appear and the “CFM” message will blink.
  • Press CFM to confirm calibration.
  • The calibration value is then displayed on the primary LCD and the secondary LCD will display the second expected buffer value.
  • Repeat steps 6.5 to 6.11 for the second buffer.
  • If the value measured by the meter is not close to the selected buffer “WRONG BUF” message will Blink. In this case check if the correct buffer has been used or regenerate the electrode by keeping the electrode in 0.1M HCl for a whole night.
  • When not in use store the electrode in 4 M KCL solution.
  • Frequency: Daily
  • Acceptance Criteria: ± 0.05 pH

SOP : Standard Operating Procedure
Q.A : Quality Assurance
Q.C : Quality control

Daily Calibration Record of pH Meter


Post a Comment