Karl Fischer Titration Guide, Part 1 presents a short, historic overview of the development of Karl Fischer’s method. It explains the chemical reaction and the two major measuring techniques: Volumetry and coulometry.
This Karl Fischer Titration Guide Part 1 explains the chemical reaction and the two major measuring techniques: Volumetry and coulometry. I also presents a short, historic overview of the development of Karl Fischer’s method.
The Karl Fischer method for the water content determination is one of the most frequently used titration methods. Published by German petrochemist Karl Fischer in 1935, it has become well renowned for a wide variety of applications and samples.
The determination of the water content according to Karl Fischer is nowadays performed by two different techniques:
- Volumetric Karl Fischer Titration, where a solution containing iodine is added using a motorized piston burette
- Coulometric Karl Fischer Analysis, where iodine is generated by electrochemical oxidation in the cell
The selection of the appropriate titration technique is based on the estimated water content in the sample:
Volumetric Karl Fischer Titration
Iodine is added by a burette during titration. Suitable for samples where water is present as a major component: 100 ppm - 100%
Coulometric Karl Fischer Analysis
Iodine is generated electrochemically during titration. Suitable for samples where water is present in trace amounts: 1 ppm - 5%
Karl Fischer Titration Guide. Part 1 — Principle.
Table of contents
1. The Karl Fischer Titration
1.1. A historic overview
1.2. The Karl Fischer chemical reaction
1.3. Consequences for practical applications
2. Volumetric and Coulometric Karl Fischer Analyses
2.1. Volumetric KF analysis 12
2.1.1 One-component KF reagent
2.1.2 Two-component KF reagent
2.1.3 Pyridine-containing reagents
2.1.4 Special reagents for aldehydes and ketones
2.1.5 Karl Fischer reagents with ethanol
2.2 Coulometric KF analysis
2.2.1 KF coulometry
2.2.2 Stoichiometry of the coulometric KF rection
2.2.3 Iodine generation
2.2.4 Generator electrode without diaphragm
2.2.5 Limitations for the use of the cell without diaphragm
3. Further Information