SOP FOR OPERATION AND CALIBRATION OF KARL FISCHER APPARATUS

byVinod Yadav -
0

  1. OBJECTIVE:

    1. To lay down the procedure for Operation and Calibration of KF Apparatus.

  2. SCOPE: 

    1. This procedure is applicable for the Operation & Calibration of KF Apparatus in QC Laboratory.

  3. RESPONSIBILITY:

    1. Quality Control Officer / Executive are responsible to follow procedure as per the procedure mentioned in this SOP. 

    2. QC Head is responsible for implementation and compliance of the procedure as per this SOP.

  4. ABBREVIATIONS

    1. SOP    :    Standard Operating Procedure

    2. QC    :    Quality Control

    3. KF        :    Karl Fischer

    4. KFF    :    Karl Fischer Factor

  5. PROCEDURE: 

    1. Reagents / Chemicals Required For Procedure:

      1. Methanol dried.

      2. KF reagent.

      3. Water.

      4. Disodium Tartrate

    2. Operation of KF Apparatus And Determination of KF Factor And Water Content of the Sample

      1. Before switching ON the instrument ensure that the apparatus and surroundings are clean and all bottles are tightly closed, silica gel in the tubing should be of blue colour. Ensure that KF reagent is present in the adequate quantity.

      2. Before determining the water content of the sample ensure that the KF factor has been determined. If not proceed to determine the factor.

      3. Ensure that the connection of the accessories is OK and switch ON the instrument. Wait for few minutes to stabilize. Place a clean dry titration vessel with the magnetic bead in the vessel holder and fill the vessel with about 30ml of methanol.

      4. Neutralize the methanol and determine the factor for KF reagent with water as follows:

    1. Quickly add about 30mg of water with the aid of a pre-weighed syringe and titrate to end point immediately.

                     OR

      1. Carefully add 30 µl of water by a micro liter syringe (as 30 µl = 30 mg) into the titration vessel after neutralization and determine the end point.

      2. Calculate the factor KFF of  Karl Fischer reagent in mg/ml as given below:

Calculation:

    KFF = W/V

        where,        

        W = Weight of water in mg

        V = Volume of KF reagent consumed in ml. 

Note: Determine the KF factor in triplicate; the relative standard deviation for the three determinations should not be more than 2.0%. Take the average of three readings.    

      1. Once the KF factor is determined then determine the water content in the sample as per respective STP of the sample.

      2. Frequency of Standardization

      1. Determine the KF factor once in a day or when required or whenever the KF reagent is changed. Record the data as per Daily KF Factor Determination (Annexure I).

    1. Calibration of KF Apparatus

      1. Calibration of Karl Fischer apparatus is done by determining the water content in Disodium Tartrate in triplicate. The percentage water content should be in the range of 15.58 to 15.74%.

      2. First standardize the KF reagent and find the KF factor as described in operation procedure.

      3. After determination of factor find the water content in Disodium Tartrate in triplicate.  Weigh accurately the finely powder about 150mg of Disodium Tartrate and transfer to the titration vessel containing previously neutralized methanol with  KF reagent. Stir for about 1-2 minutes to dissolve and start the titration. Find out the volume of reagent consumed and determine the water content by the formula given below:

         Water content =  KFF x Volume consumed (in ml) x 10/ Wright of Disodium Tartrate (in mg)

    1. The percentage water content should be in the range of 15.58 to15.74% w/w.

    2. Frequency of Calibration

      1. Daily Factor Determination:  Record the data in Daily KF Factor Determination Record. (Annexure I).

      2. Monthly calibration: Record the data in Monthly Calibration of KF Apparatus Record.

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