SOP on calibration of pH meter

• Objective:
  • To lay down a procedure for calibration of pH Meter.
• Scope:
  • This SOP is applicable for calibration of pH Meter in quality control laboratory.
• Responsibility:
  • Officer or above of QC laboratory is responsible for calibration of pH Meter
  • Head Quality / nominee of QC department is responsible for reviewing and approval of the SOP
• Accountability:
  • Head – Quality Control shall be accountable for compliance of SOPs.
• Procedure:
  • Ensure the cleanliness of the instrument.
  • Clean the electrodes with purified water and wipe with tissue paper.
  • Dip the electrode in pH-7.0 solution and press the CAL 7 key. The message ‘ENTER IF STABLE ‘will show then press the ENTER key and record the results.
  • Dip the electrode in pH -4.0 solution and press the CAL 4 key, the message ‘ENTER IF STABLE’ will show then press the ENTER key .
  • Dip the electrode in pH -9.2 solution and press the CAL 9.2 key, the message ‘ENTER IF STABLE’ will show then press the ENTER key .
  • The message will show ‘Calibration complete.
  • While checking the pH of buffer 4.0, and 7.0 clean the electrode with purified water every time.
  • After use keep the electrode dipped in the purified water.
  • Calibrate the instrument daily and record the results in the format as per Annexure- I.
  • Maintain the preparation and consumption record of pH buffer solution as per Annexure- II.
  • If the results of calibration are not conforming to the specified limits report to the department Head for an appropriate action.

List of Annexure 

• References (if any).
  • Not applicable.

• Reason for Revision
  • Not applicable due to first version.

Annexure – I

pH Meter Calibration Record

MAKE   :                                                                                                                 MODEL :

Annexure – II

Preparation and consumption record of pH buffer solution