SOP on Operation And Calibration Of Karl Fischer Apparatus

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.