In quality control department Instrument section is an essential part because every test requires a specific instrument to perform a valid analysis. Karl Fischer titration is very essential in many analyses including finding the water content in any substance. Most of the APIs used in the pharmaceutical Industry have water content in their compound, it is very essential to know the exact value of water in the compound before using the API for formulation. Therefore, Karl Fischer titration is a very important test in the laboratory. Calibration of Karl Fischer is equally important to get the right analysis values.
Principle of Karl Fischer titration
The main principle of Karl Fischer titration is based on Bunsen’s reaction between Iodine solution and sulfur dioxide in an aqueous base solution. Later on, Karl Fischer modified the reaction in a non-aqueous based medium to find the water content as neutralizing sulfur dioxide by titration.
Karl Fischer titration and calibration Procedure:-
General Precautions to follow:-
(1) The glassware to be used should be well dried and cleaned.
(2) Never drop the magnetic rotor into the beaker but slide it inside carefully.
(3) Adjust the height of the electrode such that the platinum tips are at least 15 mm above from the bottom of the beaker to avoid damage during stirring.
(4) Apply sufficient vacuum grease to all ground glass joints.
(5) Do not start the instrument unless inlet and outlet tubes are connected properly to avoid spoilage of the reagent.
(6) Clean the instrument immediately to avoid corrosion due to reagent spoilage.
(7) Close the bottle tightly immediately after use to avoid exposure to atmospheric moisture.
(i) Calibrate with distilled water.
(ii) Add about 250 ml of KF reagent in back fitted left-hand side reservoir bottle.
(iii) Remove the rubber cork and add KF grade methanol to the reaction beaker in quantity that shall sufficient for fully immersed the platinum tip. Place the rubber cork immediately.
(iv) Connect the Titrator to the mains supply and put the main switch ON and also On from the backside button. Adjust the speed of stirrer at minimum
(v) Press ‘Start’ key to start for Neutralization of moisture in methanol.
(vi) During titration display shall show the Confirmation time 20sec and also show the consumption of KF reagent in ml.
(vii) After Neutralization completion a long beep shall sound and display automatically show consume the volume of KF reagent.
For Solid sample or Raw material:
(i) Accurately weigh the sample on the balance & press ‘sample (gm-ml)’ key & ‘enter’ the weight that taken.
(ii) Transfer the weight in the reservoir bottle and then press “Start” to measure Moisture Content in the sample.
(iii) After Completion of Titration a long beep shall sound and display automatically show consumes volume of KF reagent.
(iv) Accurately take the volume of the sample by using calibrated syringe & press “density”
(v) Key & ‘enter’ the volume and density of the sample that taken.
(vi) Transfer the volume in the reservoir bottle and then press “Start” to measure Moisture Content in the sample.
(vii) After Completion of Titration, a long beep is sound, and the display automatically shows the consumed volume of the KF reagent.
(viii) Press% PPM key to show the Moisture Content in the sample it will show the moisture in
“Percentage”, “PPM” and “mg of H2O”.
(ix) Press the “batch No.” key to put the batch no. of the sample.
(x) Note down the result and take print out (If required).
The instrument Calibrates itself prior to all testings. (Fully Automatic)
List of annexures and formats.
|S. No.||Format Title||Annexure Number||Format Number||No. of Pages|
|2.||Monthly Calibration record|
|3.||Daily calibration record|
|4.||Calibration status label|
The user manual of Karl Fischer
(1) Ensure that the titration vessel is completely dry and clean at the starting of the analysis.
(2) The titration vessel is airtight during titration.
(3) Silica gel should be blue and dry.
(4) Ensure that electrode tips properly dipped in methanol.
Frequency: once in a day (KF Factor) and monthly (Equipment Calibration)
Karl Fischer titration and Calibration demand a high precision during performing the titration. Determination of water content may vary if the weight of the material differs in mg. Every aspect of analysis should be performed very carefully and should be noted down immediately to rule out any error. These days automatic Karl Fischer titrators minimized the chances of manual errors but still, precision is required to get the best results.
- Water Determination<921>-USP-31
GR Scientific, 71-0000, Aquamax Coulometric Karl Fischer Titrator-Buy Amazon
Features of Aquamax Coulometric Karl Fischer Titrator:
- Easy to use – simple to program so that only a single button needs to be pressed for a titration; all other features are automatic.
- 10 User Programmable Methods – The methods can be adjusted depending on the application and accuracy needed, this coulometric karl fischer titrator is simple to program so that only a single button needs to be pressed for a titration, everything else is automatic.
- Aquamax KF coulometric conforms to, or can be used as an alternative instrument for the following methods:- ASTM D95, ASTM D1364, ASTM D1533, ASTM D3401, ASTM D4006, ASTM D4377, ASTM D4672, ASTM D4928, ASTM D6304, ASTM E202, ASTM E203, ASTM E1064, IP74, IP356, IP358, IP386, IP438, DIN 51777, IEC 60814, BS 148, BS 6470, BS EN 60814, ISO 3733, ISO 3734, ISO7201-1, ISO 10101-3, ISO 10337, ISO 12937
- Fully portable
- Multi language display & print out
The author has 20 years of experience in the Pharmaceutical Manufacturing Companies. Have exposure to all audit documents for WHO-GMP, PIC/S, USFDA, Export documents, US-FDA documents, Validation of Pharma machinery, and Quality Control Instruments. Expert in Pharma Plant Setup and sale and acquisition of running pharma company.