Tuesday , September 26 2023

Operation, cleaning & calibration of pH meter

Operation, cleaning & calibration of pH meter

1.0       PURPOSE:

To lay down the procedure for operation & calibration of pH meter.

2.0.      SCOPE :                                 

This SOP shall be applicable for operation & calibration of pH meter of SVP manufacturing facility

Equipment Name      Make &  Model No. Equipment ID
pH meter


3.1        References

3.1.1    In-house

  • Attachments

3.2.1    Attachment- I      :       Calibration record of pH meter


4.1       Operator

4.1.1    To perform the operation as per SOP.

4.2       Production person.

4.2.1    To ensure implementation of SOP.

4.3       Production Head

4.3.1    To ensure implementation of the defined system.


  1. Quality Assurance
  2.  Production


6.1       Definitions


6.2       Abbreviation

SOP :    Standard Operating Procedure

QA    :    Quality Assurance

PROD.  :    Production

C.C.No. :    Change Control Number

KCL  :    Potassium Chloride

HCL  :    Hydrochloric Acid

WFI  :    Water For Injection

SVP   :    Small Volume Parenteral

7.0       PROCEDURE :

7.1       Operation:

7.1.1    Ensure the cleanliness of instrument before using it.

7.1.2    Ensure that instrument is located in clean and dry place.

7.1.3    Connect the power cable of instrument with main power supply.

7.1.4    Switch ON the main power supply.

7.1.5    Switch “ON” the instrument & wait for 10 second for warming up the instrument.

7.1.6    Ensure that the instrument is calibrated. If not, calibrate the instrument first before starting   the operation.

7.1.7    Wash the electrode with distilled water and wipe gently with tissue paper.

7.1.8    Take the sample solution in glass beaker & allow to attain the temperature up 25°C ±2° C  or the specified temperature.

7.1.9    Dip the electrode in the test solution which pH to measured. Ensure that bulb of the   electrode is properly dipped in solution.

7.1.8     Keep the instrument in “MEAS” mode & instrument will measure the temperature & pH of  the same solution.

7.1.9    Allow the solution to stabilize the pH with the electrode & Note the stable reading  displayed on the digital display.

7.1.10  Lift the electrode carefully and wipe gently with tissue paper.

7.1.11  Always immerse the electrode in the 3 M KCL solution, if not in use.


7.2.1    CAL      :   To perform CALIBRATION within the selected operating Mode.

7.2.2    HOLD   :   To freeze the measured reading. Press again to resume live reading.

7.2.3     MODE  :   Toggles between available measurement modes, pH/Temp, mV/Temp.

7.2.4     ENTER:    To acknowledge the entered value.

7.2.5     MEAS  :    To measure the pH & temperature.

7.2.6     MI        :     MI (memory insert) store values in memory.

7.2.7     MR      :     MR (memory recall) recall values from memory.

 7.3        Cleaning:

7.3.1     Ensure that the Instrument is in “OFF” position.

7.3.2     Wipe the body of pH meter with a clean wet, cloth and finally wipe with dry clean, dry  cloth.

7.3.3     Remove any dirty spot present on the body of Instrument with the help of Colin cleaner.

7.3.4     After every pH measurement, wash electrode with purified water and wipe with soft tissue paper before dipping in any liquid under test.

7.4        Maintenance:

7.4.1     Keep the electrode immersed in WFI.

7.4.2     Prevent the cell to dry, if it is dry; soak for 5 to 10 minutes or longer in WFI or 1 M KCl  solution.

7.4.3     Do not strike the cell against any hard surface.

7.5        Instructions for storage and Reactivation of pH meter Electrode:

7.5.1     Whenever required, fill the electrode with saturated solution of “KCl” below the filling hole.

7.5.2     Never touch the lower sensitive bulb of the electrode by hand or any other hard surface.

7.5.3     For reactivating the electrode, dip electrode in 0.1 N HCl for overnight whenever required.

7.5.4     Use electrode very carefully.

7.5.5     Whenever required change the electrolyte of electrode and KCL solution in which the  electrode remains dipped.

7.5.6     Always keep electrode in 3M KCL when pH meter is not in use.

7.6        Calibration:

7.6.1     Rinse the electrode with WFI & remove the excess water with tissue paper & clean  the temperature sensor also with WFI.

7.6.2     Put the instrument in “CAL” mode & press “CAL” key of the instrument.

7.6.3     Instrument will  demand for pH 7.0 buffer.

7.6.4     Dip the electrode & temperature sensor in prepared  first buffer solution A (7.0) pH value &  allow to stabilize the measuring value of the buffer.

7.6.5     As the displayed measured value get stable press enter & instrument will demand for  either 4.0 pH buffer or 10 pH buffer.

7.6.6     Rinse the electrode with WFI & soak the excess water with tissue paper.

7.6.7     Dip the electrode in buffer (4.0) pH value allow to stabilize the measuring value of the buffer.

7.6.8      After stabilization of second buffer, press enter, remove the buffer & rinse the electrode with WFI & soak the excess water with tissue paper.

7.6.9      Dip the electrode in third buffer (10.0) pH value & after stabilization the same buffer press  enter.

7.6.10    Wash the electrode with WFI & press the “MEAS” to verify the calibration.

7.6.11    Mention the observed pH value data of calibration in the calibration record as per   attachment : I.

7.6.12    Calibration Frequency : Daily before use.

7.6.13    Use the buffer solution readily prepared in QC on weekly basis.


Version No. 00 Effective date

Detail of revision : New SOP


Company logo Company Name & address
Calibration Record of pH meter Page No. x of y


    Date Time Buffer solution     (4.0) Buffer solution (7.0) Buffer solution (10.0) Checked by (prod.) Verified By (QA)
Observed value

(limit : 4.0±0.05)

Observed value


Observed pH


Frequency: Daily before use

About Pharmaguidanaces Channel

Ms. Abha Maurya is the Author and founder of pharmaceutical guidance, he is a pharmaceutical Professional from India having more than 18 years of rich experience in pharmaceutical field. During his career, he work in quality assurance department with multinational company’s i.e Zydus Cadila Ltd, Unichem Laboratories Ltd, Indoco remedies Ltd, Panacea Biotec Ltd, Nectar life Science Ltd. During his experience, he face may regulatory Audit i.e. USFDA, MHRA, ANVISA, MCC, TGA, EU –GMP, WHO –Geneva, ISO 9001-2008 and many ROW Regularities Audit i.e.Uganda,Kenya, Tanzania, Zimbabwe. He is currently leading a regulatory pharmaceutical company as a head Quality. You can join him by Email, Facebook, Google+, Twitter and YouTube

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