SOP FOR OPERATION AND CALIBRATION OF KARL FISCHER APPARATUS

1.0     Objective:

               The purpose of this SOP is to provide written procedure for operation and calibration of Karl Fischer apparatus.

2.0       Scope:

               This SOP covers operation and calibration of Karl Fischer apparatus.

3.0        Responsibility:

               Jr. Research Officer, Research Officer: Responsible for operation, calibration and maintenance of the instrument as per procedure.

               Head of Department: Responsible for calibration and maintenance, timely as per schedule.

              QA Officer/QA Manager: Review the records and governing the document.

4.0         Procedure:

4.1     Ensure that the instrument is visibly clean and free from dust.

4.2     Pour the Karl Fischer reagent in the reservoir bottle, delivery tip from the beaker clamp. After pouring the Karl Fischer reagent arrange them as before.

4.2    Remove the rubber cork and add about 20 - 25 ml anhydrous methanol to the beaker. Put back the cork.

4.3      Connect the titrator to mains and put the main switch ON.

4.4    Connect the leads of the solenoid value to the small three holosocket on the titrator. Switch on the toggle switch for magnetic stirrer. Adjust the speed of the magnetic stirrer with black knob, such that the magnets do not touch the electrode ends.

4.5      Check the display, if shows not 0.000 press the clear button display shows 0.000.

4.6       Press the ‘START’ button for a second and release. The red light of the titrator  glows, this shows the titration is on.

4.7        When the end point approaches, the green light appears and titration stops automatically.

 4.8     Presses the clear button display shows 0.000, now, put the sample into the beaker and start the operation by pressing the start button.

4.9      As the end point is approached, titration stops automatically.

4.10    After completion of titration results obtained on the display and note down the result.

4.11      Record the details in the instrument usage log book (Annexure - 1).

5.0       Calibration:

5.1      Arrange the apparatus as described above.

5.2      Find Factor:

5.2.1 Perform blank titration and transfer accurately weighed quantity, about 150 mg, of Disodium tartrate into the beaker.

5.2.2   Start the titration and note down the volume of Karl Fischer reagent consumed.

5.2.3  Calculate the Karl Fischer factor as follows:

                  Karl Fischer factor:      15.66 X Weight of Disodium tartrate in mg.                  

                                                    Volume of Karl Fischer reagent consumed in ml. X 100

5.2.4       Perform the factor estimation in duplicate and take the average of the two for calculation.         

5.3         Linearity Check:

5.3.1      Transfer accurately weighs different quantity about 50 mg, 100 mg, 150 mg, 200 mg and 250 mg of Disodium Tartrate into the beaker.

5.3.2    Titration its and note down the volume of Karl Fischer reagent consumed.

5.3.3      Plot the graph of Karl Fischer reagent consumed value verses weight of Disodium tartrate.

5.3.4      The graph should be linear and Correlation coefficient not less than 0.99.

5.4       Now check the water content with water as sample.

5.5       Use a micro liter syringe for weighing water.

5.6      Transfer approximately 3 - 4 drops of water into the beaker and start the instrument. Note down the weight of water taken.

5.7     Record the volume of Karl Fischer reagent consumed for titration.

5.8    Calculate the water content using the following :

               % Water =    Factor X Volume of Karl Fischer reagent consumed in ml. X 100

                                                Weight of water in mg.

               Limits: 99.8 % to 100.2 %

5.9          Perform the estimation in duplicate.

5.10        Record the details in Karl Fischer apparatus calibration record format (Annexure - 2).

5.11     Calibration Frequency:

               Once in a Month

6.0     Routine maintenance:

6.1       Clean the instrument with dry cloth

6.2       Check the leakage in rubber tubes, if leakage observe replace the tube.

6.3        Clean both  electrode with Methanol and then with tissue paper.

7.0          Documentation:

7.1          Annexure – 1 -   Karl Fischer apparatus usage log book.                     XXX/FRM/000

7.2          Annexure – 2 -   Karl Fischer apparatus calibration record format.     XXX/FRM/000    

8.0         History of Revision:

Revision No.	Effective Date	Revision details	Reason for revision

Annexure – 1
Date	A. R. No.	Name of Sample	B. No.	Used by	Remark
SOP No. : XXX/SOP/000-00                  Format No. : XXX/FRM/000-00

Annexure – 2
Calibration of Karl Fischer Apparatus	Page No. : 01 of 02
Calibration Date   :                                                Next due date for calibration : Make                    :                                                Model No. :
1.0               Factor :              Weight of Disodium Tartrate :             (1)                                                                            (2)              Karl Fischer reagent consumed in ml.  (1)                                                                                            (2)                              Karl Fischer factor:          15.66 X Weight of Disodium tartrate in mg.                                                                           Volume of Karl Fischer reagent consumed in ml. X 100                         Factor (1)                         Factor (2)                                            Average Factor : 2.0    Linearity : Sr. No. Weight of Disodium Tartrate in mg Volume of Karl Fischer reagent consumed in ml Remarks 1 50 2 100 3 150 4 200 5 250 Correlation Coefficient : Limit : NLT 0.99
Remarks : Satisfactory / Not Satisfactory
Calibrated by  :                                                                      Checked by      :
SOP No. : XXX/SOP/000-00                                     Format No. : XXX/FRM/000-00