Water determination in products with high sugar content by infrared drying

Instead of measuring the real water content, very often drying mass loss is determined. Not only water contributes to this mass loss, but all volatile materials under the applied drying conditions. On the other hand, very tightly bound water may elude detection. The mass loss by drying does therefore not necessarily correspond to the water content of the sample. To accelerate analyses, in comparison with the classical oven method, more efficient heating sources have been introduced. Infrared dryers belong to this category. This more vigorous heating tool involves a higher risk of decomposition of the sample with production of further volatile compounds. The danger of obtaining erroneous results is particularly high for heat-sensitive products, such as sugars. The objective of this work was to find parameters for the infrared drying of sugars and products with a high sugar content such that the results correspond to those determined by the Karl Fischer titration which selectively measures the water content.