SOP For calibration of pH meter is described in this post which you can follow in the section of the General Industry SOP.

Objective
To provide a standard operating procedure for the calibration of pH meter temperature sensor.
Scope
This procedure is applicable to pH meter.
Responsibility
QC Analyst
Accountability
Manager Quality Control
Procedure
  • Keep the sensor probe of reference calibrated digital thermometer in the beaker containing water for injection (WFI) / purified water (PW) of about temperature 35°C.
  • Add cold WFI/PW slowly drop wise and bring the temp. between 27°C to 30°C.
  • Compare the temp. shown by reference calibrated digital thermometer and pH meter & record it.
  • Add WFI/PW in some more quantity slowly drop wise to bring the temp. between 26°C to 23°C.
  • Compare the temp. shown by reference calibrated digital thermometer and pH meter & record it.
  • Add cold WFI/PW slowly drop wise and bring the temp. between 20°C to 22°C.
  • Compare the temp. shown by reference calibrated digital thermometer and pH meter & record it.
Acceptance Criteria: ± 3°C
Frequency: Twice in Year.