What is Karl Fischer Titrator and How Does It Work?

What is Karl Fischer Titrator and How Does It Work?

Introduction:

The Karl Fischer Titrator is widely used for moisture or water determination in solid, liquid and gaseous samples. It has a host of applications in industrial quality control.

The Karl Fischer reaction is based upon the oxidation of sulfur dioxide by iodine with the consumption of water in a buffered solution:

I₂ + 2H₂O + SO₂ -> 2HI + H₂SO₄

The Karl Fischer titration is a classic titration method that uses coulometric or volumetric techniques to determine water content in a sample. Water can only be titrated if it is freely available so it's important to consider sample preparation before carrying out Karl Fischer titration.

Determination of the water content of a substance is essential for quality control in many applications, including pharmaceutical agents, foodstuffs and chemicals. One of the most widely used and accurate methods of quality control is Karl Fischer (KF) titration.

Application:

The water content in a large array of materials can be determined using KF titration. These include foodstuffs, chemical reagents, pharmaceuticals and plastics. The amount of water titrated may range from one ppm to 100% water. This includes both surface water and that bound within crystals.

Coulometric Karl Fisher Titrator:

Volumetric Karl Fisher Titrator: