Correction of the sample weight in hermetically sealed DSC pans

The weight of a DSC sample is routinely determined as the difference between the weight of the pan containing the sample and the empty pan. If the sample is sensitive to atmospheric moisture, weighing is usually performed after sealing the pan. However, we have observed that sealing induced changes in the measured weight of the pan when aluminum DSC pans were hermetically sealed with a Perkin-Elmer Volatile Sealer Assembly. The difference between the weight of sealed and non-sealed DSC pans was about 10 μg and independent of the presence of a sample in the DSC pan. Correction for this difference is important in applications that require precise weights of DSC samples.