AB 201-320

In principle the 774 Oven Sample Processor can be used with all samples that release their water when heat is applied. However, the KF oven method is essential whenever direct volumetric or coulometric Karl Fischer titration is impossible because the sample contains interfering components or, due to its consistency, is difficult to place in the titration vessel.

The combination of the 774 Oven Sample Processor with coulometric Karl Fischer titration (756 or 831 KF Coulometer) is ideal for samples with a low water content. Foodstuffs, pharmaceutical products, plastics or mineral oil products can be analyzed fully automatically and extremely accurately. On the other hand, a volumetric Karl Fischer titration using a KF Titrino is to be preferred for samples with a very high water content (>50%).

In accordance with the gas extraction principle the water is driven out of the heated sample by a stream of dry carrier gas and transferred to the titration vessel, where the water is determined by KF titration.

For temperature-sensitive samples, e.g. foodstuffs, the water can be released gently at lower temperatures by simultaneous extraction with methanol. In this way it is possible to prevent any water being released by decomposition.

This Application Bulletin uses examples from the food, pharmaceutical, plastics and petrochemical industries to describe automatic Karl Fischer water determination using the 774 Oven Sample Processor and a KF Coulometer. Information concerning the combination of the Oven Sample Processor with a volumetric KF titrator is given in brackets.

 AB_280_1_d.pdf (311 KB)

 AB_280_1_e.pdf (299 KB)