•    OBJECTIVE
  • This SOP describes the procedure for operation and calibration of pH Meter.

• SCOPE
  • This procedure is applicable for operation and calibration of pH Meter in Quality Control Department.
• RESPONSIBILITY
  • Officer / Executive-QC – responsible for Implementation of SOP.
• ACCOUNTABILITY
  • Manager Quality Control
• PROCEDURE
• Operation
  • Before operating the instrument, clean the instrument properly.
  • Place the instrument on clean and flat surface near a power point.
  • Connect the unit to 230 V mains power supply.
  • Switch on the mains.
  • Press the ON/OFF key, pH meter automatically starts in last mode of operation.
  • Rinse the electrode with purified water & wipe the electrode.
  • Dip electrode in sample & show the pH.
  • After completion of pH clean the instrument.
  • Record the activity of instrument in log book of pH meter.
• Calibration
  • PH meter calibrated daily with pH 4.0 and 7.00 buffer solutions.
• Preparation of Buffer Solutions
  • Collect the tablets and follow the instruction as per manufacturer in this bottle for buffer solution pH 4.0 and 1.0.
  • Prepare the buffer solution after every 07 days. If there is any change in physically appearance, make the fresh buffer solution.
• General Instructions
  • Check the validity of the buffer solutions before use.
  • After calibration do not switch off the pH meter. If done so, again calibrate the pH meter before use.
  • To remove excessive water from the electrode gently touches it over with a small piece of tissue paper. Never rub the electrode with tissue paper.
  • If pH meter is not in use for more than 48 hours, then immerse the electrode in saturated Potassium Chloride solution for one hour before use.
• Calibration Procedure
  • Press the ON/OFF key, pH meter automatically starts in mode of operation.
  • Rinse the electrode with purified water and wipe the electrode.
  • Transfer approx. 50ml each buffer solution from stock buffer solution in 100 ml capacity dry beaker.
  • It will show “MEAS” on the top of display screen.
  • Press once again on/off button, it will show “CAL”. Wash the electrode & Dip in the buffer solution pH: 7.0 and wait till the upper value get stabilize and show ready mode.
  • Press enter. It will calibrate the value.
  • Take out and wash the electrode. Put it in buffer solution pH: 4.0 and wait till the upper value get stabilize and show ready mode.
  • Take out and wash the electrode.
  • Electrode should be always dipped in saturated KCL.
  • Fill the Calibration status label Format and affix it on the instrument.
  • Report any discrepancy observed during calibration of instrument to Quality Control In-Charge or his designee for corrective and preventive action.
  • Calibration should be required after maintenance.
• Precaution and Cleaning:
  • Wash the electrode and reference junction in purified water.
  • Do not leave the electrode dry; keep the electrode in saturated KCl.
  • Do not wipe the glass electrode bulb with any coarse material. Use only tissue paper.
  • Dissolve the salts deposits by immersing the in a container filled with some tap water for ten to fifteen minutes. Then thoroughly rinse with purified water.
•     ABBREVIATION

     SOP      –  Standard operating procedure

     QC       –  Quality Control

•   FORMAT

NIL

•    DISTRIBUTION LIST

Reshma Verma