Meaning
Gravimetric analysis procedures determine the total moisture and volatile content by weighing a sample before and after a heating cycle. Measuring the loss on drying involves heating the material to a specific temperature and holding it there until the weight stabilizes. This technique is a standard quality control test for powders, pellets and food products.
The resulting percentage represents everything that evaporated during the process, including water and organic solvents.
Volatile Mass
Heating the sample drives off any substance with a boiling point below the test temperature. In a loss on drying test, the final weight is subtracted from the initial weight to determine the total mass lost. This method is simple to perform but does not distinguish between water and other volatile components.
Thermal Cycle
Accuracy depends on choosing a temperature high enough to release volatiles but low enough to avoid burning the material. If the loss on drying test is conducted at too high a temperature, the sample may undergo chemical decomposition, which would provide a false reading. Standardized protocols define the exact time and heat settings for each material type.
Moisture Estimation
Laboratories use these results as a proxy for moisture content when the level of other volatiles is known to be low. Because the loss on drying process takes time for the weight to reach a steady state, it is often used for batch verification rather than real-time control. Modern halogen moisture analyzers have sped up this process for floor-side testing.
