The NEW 860 KF Thermoprep opens up new possibilities for determining the water content by the Karl Fischer method of samples that are either insoluble, react with the KF reagent or that cannot be placed directly in the titration vessel for other reasons.
The samples are no longer placed in the oven in weighing boats, but each sample is now contained in its own tightly sealed sample vial. The oven can be used with all volumetric and coulometric KF titrators.
Water determination of "difficult" samples can now be achieved, as the sample is not put directly into the titration cell. Difficult samples can be categorised as follows:
Many substances (e.g. plastics or inorganic salts) release their water only slowly or at high temperatures.
An additional problem is the low solubility of certain samples in alcohols e.g. plastics
In these cases traditional methods recommend the use of toxic solvents to promote dissolution or alternatively extensive sample preparation procedures.
If a sample is introduced directly into the titration cell the latter can be strongly contaminated
Which means that it is necessary to exchange the titration solution and clean the cell frequently.
Finally there are various substances (e.g. ascorbic acid) that undergo side reactions with KF reagents thus falsifying the result.
Examples of difficult samples include, oil (containing additives), plastics, paint, pharmaceutical products, hair and wound-care products, to name but a few.
The 860 KF Thermoprep from Metrohm drives off moisture from solid and liquid samples for the subsequent coulometric or volumetric determination of the water content by the Karl Fischer method (temperature range 50-250 °C).
The 860 KF Thermoprep offers the following benefits:
Strictly reproducible analysis conditions for all samples; this is shown by the considerably improved precision of the results.
Manual sample preparation is reduced to a minimum.
Considerable savings in time.
No contamination of the oven by the sample; consequently there are no carryover and memory effects.
Improved water release from the sample as the carrier gas does not just pass over the sample but directly through it.
The 860 KF Thermoprep is available in 3 options:
Option 1 is as an oven on its own, option 2 is as an oven in conjunction with a coulometric KF (for low level water), and option 3 is with a volumetric KF (for high level water).