What is loss on drying?
Moisture analysis includes a variety of methods for measuring moisture content in both high level and trace amounts in solids, liquids or gases. Trace moisture in solids must be controlled for biopharmaceuticals and heat treatment processes. Loss on dry is a classic method of measuring the moisture in solid or semi-solid materials.
How to perform loss on drying?
In this technique the sample is weighed first, following heated for about 30 minutes under prescribed conditions, cooled in the dry atmosphere of a desiccator, and then reweighed accurately. If the volatile content of the solid is primarily water, loss on drying gives a good measure of moisture content. By general, sample with the layer about 5 mm, and no thicker than 10 mm, is place 1-2g into the weighing bottle to be tested. Because the traditional method requires relatively long time, automated moisture analyzers have been developed that can reduce the time necessary for a test from hours to just a few minutes. If the sample melts at a lower temperature than that specified drying temperature, maintain the bottle for 1 to 2 hours at a temperature 5-10℃ lower than the melting temperature, and then dry it at the specified temperature.
What is loss on drying applied to?
Loss on drying measures both the water and volatile impurities, such as alcohol and fat evaporate with the water, while Karl Fischer titration measures only the water content in the sample. It is often used in those cases where the loss sustained on heating may be not entirely water.
