The water content of many samples is difficult to determine because they are only slightly soluble in alcohols, contaminate the titration cell or undergo side reactions with the Karl Fischer reagent
Traditional methods recommend the use of toxic solvents to promote dissolution of the sample or alternatively extensive sample preparation procedures.
A more elegant solution is achieved by using a Karl Fischer oven as with this technique only the water content of the sample is transferred to the titration cell.
However, instead of introducing the sample into the oven by means of a sample boat, the vial technique is used, i.e.
the sample is weighed directly into the sample vial, sealed and transferred to the oven.
Combined with the sophisticated methodology of the KF Thermoprep this results in the following improvements:.
Strictly reproducible analysis conditions yield results with markedly improved precision.
Manual sample preparation is reduced to a minimum.
You achieve considerable time savings.
There is no contamination of the oven and the titration cell; consequently there are no carryover and memory effects.
The reagent consumption diminishes significantly as the titrant has to be exchanged only infrequently.
Water release from the sample improves as the carrier gas does not just pass over the sample but directly through it.
Depending on the sample's water content, the subsequent KF water determination can be carried out volumetrically or, in the trace region, coulometrically.
