Karl Fischer Ovens
What is Karl Fischer?
The Karl Fischer Method was invented by a chemist by that name. It is a process based on the reaction of iodine with water. The starting point of the measurement is the introduction of the test sample into an airtight titration cell containing a solvent. The reaction results in a substance with very low conductivity.
The conductivity of the sample in solution is reduced by the Karl Fischer Reaction. The end-point of this process is determined when the conductivity is reduced to the level present before the sample was introduced.
The Karl Fischer Method is one of the few techniques that will measure water content and not be affected by other volatile elements. It has the added benefit that it will often get at bound water.
Why a Karl Fischer Oven?
For a product to work with the Karl Fischer Chemical Reaction, it needs to be able to dissolve in a solvent compatible with the Karl Fischer Reagents. Some materials will not dissolve in or will cause side reactions with acceptable solvents.
Other materials will not release their water except at high temperatures; for example, products such as plastics and a number of inorganic salts.
To use the Karl Fischer Method with these materials, the sample must be heated, in some cases to 300°C. A Karl Fischer Oven or Evaporator is used for this purpose. The oven is, in effect, a tube furnace. The moisture driven off in this furnace is transferred to the titration cell by a dry, inert gas.
Our solution to this type of material is to use an oven manufactured by KEM, along with a matching Coulometric Karl Fischer Titrator for samples with low moisture or a Volumetric Karl Fischer Titrator for samples with higher water content.
Karl Fischer Oven/Titrator Combinations to Perform Moisture Tests
These combinations are an ADP 511 Oven/Evaporator with a Coulometric Titrator, or the same Oven/Evaporator with a Volumetric Titrator.
Photographs of these combinations are shown in the left column of this page.
Call us at 800-621-4778 to learn more.