Aim: To provide Procedure on Operation And Calibration Of Karl Fischer Apparatus.
Objective: This standard operating procedure explains how to use and calibrate the Karl Fischer apparatus.
Responsibility: Chemist/Executive Q.C. for following this procedure.
Accountability: The Manager of Quality Control is accountable for overall compliance with this SOP.
Procedure: Cleaning
- After finishing the analysis, empty the KF reagent from the titration flask into the KF waste bottle. Clean the flask by rinsing it with methanol.
- Wipe the electrode with tissue paper to keep it clean.
- If needed, use Isopropyl alcohol to clean the outer surface of the instrument. Dry it with tissue paper.
- Whenever necessary, replace the ‘self-indicating’ coarse silica.
- If the color of the silica gel changes from blue to pink, regenerate it by heating it in the oven until it turns blue again.
- Once the KF apparatus is cleaned, document the details in the instrument logbook according to the current SOP version.
Related SOP: SOP for Analysis and Release of Packing Materials
Operation:
Determining Water Content (Not Easy Soluble Substances):
- Set the time to 30 seconds.
- Press ‘Reset’, ‘Run’, and F3 for pre-titration.
- After, you’ll see a result.
- Press F3 and input the sample ID.
- Add sample to the vessel.
- Input sample weight, then press F3 twice.
- The machine will print the water content.
- Sample Size: Choose a sample with 5.00 to 10.00 mg of water.
Precautions:
- For liquid samples, inject a bit more.
- Keep syringes and needles clean and dry.
- Test samples with the lowest moisture first.
- If moisture is unknown, adjust the sample size.
- Rinse syringes before using.
Calibration:
- Neutralize water in methanol.
- Add 100 mg of sodium tartrate dihydrate.
- Do titration and record volume.
- Repeat three times and find the average.
- The standard value is 6.0.
Frequency:
- Once a month.
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