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