Calibration and Operating Procedure for pH Meter

January 10, 2024April 6, 2016 by Pharmaceutical Guidanace

Objective:To lay down procedure for Calibration and Operation of pH Meter.

Scope:This standard operating procedure is applicable for formulation plant of Pharmaceutical company name with location.

Make: Mettler Toledo.

Responsibility
- Trained worker / Operator shall be responsible for performing the calibration and operation of the equipment as per this SOP.
- Production Supervisor / Officer shall be responsible for implementation of this SOP.
- Head-Production / designee shall be responsible for compliance of this SOP.
Abbreviations and Definitions

pH – – log [H⁺]

MTC – Manual Temperature Compensation

ATC – Automatic Compensation

HDPE – High Density Poly Ethylene

SOP – Standard Operating Procedure

mv – milivolt

QA – Quality Assurance

Procedure
- Calibration Procedure:
  - Take 20 ml Hamilton buffer solution from buffer bottle in its measuring cup by pressing the bottle.
  - Use this solution within one week. calibrate the pH meter weekly.
  - 1^st-Point Calibration for pH “7.00”
    - Remove the cover from tip of the electrode.
    - wash electrode with purified water and dry with tissue paper
    - Set the temp. at 25ºC by pressing temp key and Up/ Down scroll key.
    - For Auto Mode, place the electrode in a calibration buffer of pH 7.00 and press ‘Cal’
    - End point reaches automatically. It shall display pH at particular temperature.
    - For manual Mode press A.
    - Meter shall display value of calibrated pH and freeze the buffer value.
    - To return to Sample measurement press Read A key.
  - 2^nd – Point Calibration for pH “4.01”:
    - After 1^st point calibration, wash electrode with purified water and dry with tissue paper.
    - Place the electrode in solution of pH 4.01 buffer and press ‘Cal’
    - pH meter shall display reading automatically when endpoint reaches and calibrated, for manual mode press Read A key.
    - pH meter shall display pH value on the screen and value shall be freezed.
    - To return in measurement by pressing Read A key.
  - 3^rd – Point Calibration for pH “9.21”
    - Perform the steps as in 1^st and 2^nd end point calibration.
  - Frequency of Calibration:
    - Calibrate the pH meter weekly.
    - Record all the observation in pH calibration record (Annexure-1).
    - After calibrations affix ‘calibrated’ tag on the equipment.
  - Operating Procedure:
    - Temperature Setting:
      - Press Temperature key to set the Temperature in manual mode and its value can be increase or decrease by using UP/DOWN scroll key.
      - By press READ A key for confirming the setting?
      - By pressing and holding pH/ mv key printer signal shall be display in screen and print shall be obtained.
    - Place the electrode in the sample and press ‘ReadA’ key for the measurement.
    - Display shows the actual pH of the sample.
    - Wait till the sensor output valve has been stabilized, the display freezes automatically and ‘A’ appears on the screen.
    - By pressing and holding the ‘read A’ key, auto and manual end point mode can be interchanged.
    - To measure mv press pH/mv key, during the pH measurement.
  - Forms and Records
    - pH METER CALIBRATION RECORD – Annexure-I
  - Distributions
    - Master Copy – Documentation Cell (QA)
    - Controlled Copies – Production and Quality Assurance

History

Date

Revision

Number

Reason for revision

–

New SOP

Annexure-I

pH METER CALIBRATION RECORD

Equipment ID No.:

Date and Time

Temperature

1^st Point Calibration

2^nd Point Calibration

3^rd Point Calibration

Calibration

Done By

Checked By

Due Date

Buffer Solution

±0.01

Observed Value

Buffer Solution

±0.01

Observed Value

Buffer Solution

±0.02

Observed Value

OK / Not Ok

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