STANDARD OPERATING PROCEDURE CALIBRATION OF pH METER

STANDARD OPERATING PROCEDURE

SUBJECT:                      CALIBRATION OF pH METER

DEPARTMENT           : QA SOP NO.                      : Page No                       : Effective Date             : Next Review                : SOP REVISION           :

1.0       OBJECTIVE:

To provide guidelines for Calibration of the pH meter.

2.0       POLICY: 

To lay down a procedure for Calibration of PH meter.

1.0                PROCEDURE:

3.1       To standardize the pH meter select two buffer solutions whose difference in pH does not exceed four units, such that the expected pH of the material undertest false between them.  

3.2  Prepare the buffer solutions having pH 4, 7 & 9.20

3.2.1        Buffer pH 4.0 (IP-2007 4.1.B)

Place 2.86 ml of glacial aceticacid & 1.0 ml of 50% wt/volume solution of NaOH in 1000ml volumetric flask add water to volume and mix. Adjusts the pH if necessary to 4.0.

3.2.2        Buffer solution pH 7.0 & 9.2 are prepared as directed on the instructions of the pack.

3.2.3        Prepare the buffer solutions on the first working day of the weak.

3.3       Switch “on” the equipment. Remove the electrode from the water; wipe out the water on the electrode using tissue paper than rinse the electrode with CO₂ free water than wipe out with tissue paper.

3.4       Immerse the electrode in one of the buffer solution, adjust the temperature control and adjust the calibration control to the observed pH value identical with the buffer solution under examination, by shaking it slowly.

3.5       Takeout the electrode washed with CO₂ free water, wipe it with tissue paper.

3.5         Repeat the procedure using second buffer solution.

3.7       Place the electrode the third buffer solution and check the pH without adjusting the calibration control at same temperature.

3.8       Note down the pH readings of the solutions in Calibration register before making necessary adjustment.

3.9       The readings of all three buffers should not differ more than 0.05 units.

3.10     If the difference is more than 0.05 units examine the electrodes & if they are faulty, replace the     electrode.

4.0       FREQUENCY:  Daily.

5.0       RESPONSIBILITY: Executive (QA) / Jr. Executive (QA).

6.0       REVIEW GUIDE: Calibration Record.

7.0       ANNEXURE: -------

8.0       SOPs DISTRIBUTION:

            This SOP shall be distributed to following Departments:

Name of the Department	Master Copy	Circulatory Copy
QA/QC	√	√
Production	x	x
Warehouse	x	x
General	x	x
Maintenance	x	x