Using the Karl Fischer method, the 860 KF Thermoprep determines the water content of samples that are either insoluble, react with the KF reagent or cannot be placed directly in the titration vessel.
The sample is no longer placed in the oven in weighing boats, but 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 placed directly into the titration cell.
Difficult samples can be categorised as the many substances (for example, plastics or inorganic salts) that release their water slowly or at high temperatures.
An additional problem is the low solubility of certain samples in alcohols.
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.
There are also various substances, such as ascorbic acid, which 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.
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.
The 860 KF Thermoprep is said to provide: strictly reproducible analysis conditions for all samples; reduced manual sample preparation; time savings; no contamination of the oven by the sample; and 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 three options: as an oven on its own; as an oven in conjunction with a coulometric KF (for low level water); and with a volumetric KF (for high level water).
