Extrapolated onset temperature, differential

Figure 1 A hypothetical differential scanning calorimetric profile for an endothermic transition, where Tm is the transition midpoint, and Ti and T2 are the extrapolated onset and completion phase transition temperatures, respectively.

The differential scanning calorimetry thermogram of lomefloxacin hydrochloride obtained on a Shimadzu DSC-50 instrument at a scan rate of 5°C/min is given in Figure 19. The thermogram exhibits a sharp melt peak with an onset temperature of 294°C and an extrapolated melting point of about 304°C followed by decomposition. 

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