|STANDARD OPERATING PROCEDURE|
|Title||:||Procedure for Operation & Calibration of pH Meter
- This SOP describes the procedure for operation and calibration of pH Meter.
- This procedure is applicable for operation and calibration of pH Meter in Quality Control Department.
- Officer / Executive-QC – responsible for Implementation of SOP.
- Manager Quality Control
- 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.
- 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.
SOP – Standard operating procedure
QC – Quality Control
- DISTRIBUTION LIST
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