Water - An Important Parameter for the Preparation and Proper Use of Certified Reference Materials

Property values of powdered certified reference materials (CRMs) are very often related to dry mass. The dry mass is indirectly determined by measuring the moisture content of the sample. The most commonly used methods are the drying oven method and the Karl Fischer titration (KFT). It is well known that these two methods may give different values for the moisture/water content. In this study thermogravimetry was used to simulate the drying oven method and to investigate the reasons of the differences between both moisture/water content determination methods. A mass spectrometer coupled to a thermobalance (TGMS) added further useful information regarding the release of volatile substances and the decomposition of the material during the drying process. In addition, water adsorption kinetics of several powdered food CRMs were and individual constituents thereof were evaluated. The speed of water uptake and the water uptake capacity were described using an exponential function.

YAZGAN Seyhan;  BERNREUTHER Alexander;  ULBERTH Franz;  ISENGARD Heinz-Dieter; 

2006-11-10

ELSEVIER SCI LTD

JRC33371

https://publications.jrc.ec.europa.eu/repository/handle/JRC33371,