Fig. 1 shows that in comparison to the pure compound
signal (a sharp, narrow and high signal) the signals from cuts are
broader and shorter, with the endotherm from the simple
distillation fraction being broader and shorter than that from rectification. This indicates that for narrow cuts more sample is needed to achieve an endotherm with a size comparable to that of an endotherm of a pure compound. It was shown in reference [16] that there is a substance specific optimal sample size below which determination of the onset temperature of the boiling endotherm could be of lower accuracy. One of the major reasons for the
broadening and shortening of the DSC endotherm is that a cut is not a single compound. The cut contains a distribution of