karl fischer titration slide
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Faruk Hossen ID:20151109005
Karl Fischer Titration
KF IntroductionReagents
KF InstrumentsTypes
Endpoint indication ApplicationsLimitations
TOPICS
Karl Fischer titration is a classic titration method in analytical chemistry that uses coulometric or volumetric
titration to determine trace amounts of water in a sample.
INTRODUCTION
Basic ingredients of KF reagents
* Iodine* Sulphur
dioxide* Buffer* Solvent
I2
SO2
ImidazoleMethanol
Instruments of KF
*Drying tube*Cathode chamber*Sample injection cap*Detection electrode*Electrode analysis*Rotor*Drain cook*Anode chamber
pH dependency
log K
pH
KF titration methods
Coulometric KF titration
Iodine is generated in titration cell (anodic oxidation)
Volumetric KF titration
Working medium & titrant
The main compartment of the titration cell contains the anode solution plus the analyte. 1.alcohol (ROH), 2.a base (B),3. SO2 4. I2. A typical alcohol that may be used is methanol or diethylene glycol monoethyl ether, and a common base is imidazole.
Coulometric Titration
Volumetric titration The volumetric titration is based on the same principles as the coulometric titration except that the anode solution above now is used as the titrant solution. The titrant:1. an alcohol (ROH),2. base (B),3. SO2 4. a known concentration of I2.5. Pyridine has been used as the base in this case.
Endpoint indication
• in technical products
(oil, plastics and gases)• in cosmetic products • in pharmaceutical products• in food industry
Aplication of kf
• The major disadvantage with solids is that the water has to be accessible.
• Easily brought into methanol solution.• KF is selective for water
Limitations
THANKS