Karl Fischer titrator is one of the instrument in the quality control laboratory which is used to determine the water content/moisture content of the sample. The operation of Karl Fischer apparatus plays a major role to generate an accurate result of % water content present on the sample.
Proper operation of karl fischer apparatus is a important to as well as proper cleaning and precaution while handling of karl fischer apparatus is also a important for the water content determination.
What is the operation of Karl fischer apparatus procedure?
Safety Precautions while Karl fischer titration:
- Wear gloves, nose mask and goggles while handling of Karl Fischer apparatus.
- Do not drain the waste of kf reagent directly into the washbasin or sink. Discard kf reagent waste into a respective solvent waste container only.
- The waste bottle shall be emptied from time to time to prevent pump damage due to solvent aspiration.
General requirements and precaution of karl fischer apparatus:
Before analysis precautions for Karl fischer titration:
- Ensure the instrument is connected to the power supply and tubing’s appropriately before usage.
2. Wipe the surface of the instrument with lint free cloth, ensure while cleaning instrument is in switched off condition.
3. Before removing the tubing connection, the dosage unit shall be in the drive unit, otherwise, the reagent may stick into the inner part of the instrument.
4. Remove the dosing unit only when the piston of the dosing unit or the drive pushrod is in zero position.
5. Verify that there is no air bubble trapped into the tubing, inside the burette before starting the analysis.
6. Ensure that previous material is not present into the KF titration vessel before proceeding for next analysis.
7. If any material is deposited on the electrode wash with methanol and wipe with tissue paper.
8. If the material is not removed after washing, deep the electrode into concentrated Nitric acid for minutes. Rinse with water and followed by the solvent.
9. Ensure that anti-diffusion burette tip is properly attached.
10. Specially dried methanol shall be used for KF titration.
11. Clean the titration vessel with sufficient amount of methanol.
12. Use dry titration vessel for calibration of Karl Fischer reagent.
13. Sonicate the anti diffusion valve if any blockage observed.
14. Ensure that electrode tip are connected with each other. It shall be maintain them in parallel position.
15. Replace the desiccant weekly once.
16. Starting speed shall be adjusted to avoid vertex formation.
17. Always make sure that adequate quantity of KF reagent is available in the bottle.
18. If the sufficient quantity is not available then replace with new kf reagent and standardize it before use.
19. Whenever the burette reagent changed, flush the burette and its tubing with a reagent about 5 times before standardization.
20. Recirculate the kf reagent by keeping the dispensing end tip in the reagent bottle.
21. Swirl the kf reagent bottle to harmonize the solution.
22. Standardize the kf reagent before use.
23. It is preferable to use a kf reagent with a water equivalency factor of less than 2mg/ml if water traces amount is less than 1%.
During analysis precautions while operation of Karl fischer apparatus:
- If the abnormal Karl Fischer titration is observed or if the drift fluctuation is observed, place the platinum electrode in the conc. Nitric acid for 20 mints.
- Use fine powder for solid finished dosage forms analysis.
- Ensure that no material is stuck inside wall of vessels while transferring the sample.
After Analysis Precautions while operation of Karl fischer apparatus:
- Dip the electrode in fresh methanol.
- After burette, use flush the burette and its tubes with methanol for 5-6 times and after that with kf reagent also.
Types of burette tips:
There are two types of burette dispensing tips available for dispensing of the liquid.
- The dispensing tip with plane tip shall be used for non-immersed titration.
- The dispensing tip with a broad round tip shall be used for immersed titration.
- Incase of malfunctioning or breakdown during routine operation, keep the instrument on hold and place the under maintenance
- Get serviced by the service engineer or eternal service provider.
- Calibration shall be performed and repair on the recommendation of the vendor.
- After serviced by service engineer or service provider perform the calibration of instrument for its routine usage.
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