Karl Fischer Titration

What Is Karl Fischer Titration?

Karl Fischer titration is a titration method which uses volumetric or coulometric titration to determine the trace quantity of water in the sample. It was invented by a German chemist by name Karl Fischer in the year 1935.

Karl Fischer Titration Principle

This experiment is based on iodine/iodide reaction. Water reacts with iodine and reaches endpoint when all the water is consumed. This method uses an organic base (B), alcohol, iodine, and sulfur dioxide. In the original KF experiment, the alcohol used was methanol and organic base used was pyridine. During the experiment and course of the titration, the sample is added with iodine and the amount of iodine that is used to consume all the water in the sample is measured.

Karl Fischer Titration Equipment

Drying tube, sample injection cap, electrode analysis, Drain cook, a cathode chamber, detection electrode, rotor, anode chamber, KF reagent.

Ingredients of KF reagent:

Iodine, Buffer (Imidazole), sulfur dioxide, solvent (methanol).

Karl Fischer Titration Procedure

There are two types of Karl Fischer titration. They are:

  • Volumetric determination – This technique is suitable to determine water content down to 1% of water. The sample is dissolved in KF methanol and the iodine is added to KF Reagent. The endpoint is detected potentiometrically.
  • Coulometric determination – The endpoint is detected in this experiment electrochemically. Iodine required for KF reaction is obtained by anodic oxidation of iodide from solution.

Karl Fischer Titration Applications

  • It is used in technical products such as plastics, oils, gases.
  • It is used in pharmaceutical products.
  • It is used in cosmetic products.
  • It is used in industry.

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Practise This Question

When Sodium carbonate and sodium sulphite react with hydrochloric acid (two separate reactions), the gases evolved are