Polymorphic purity calorimetry

Each initial salt needs to be studied for polymorphic purity, and the presence of solvates. Ideally, only one polymorphic form will be present. This polymorphic purity will be measured by one of the solid-state technique s) listed in Section II.D. Initial screening will typically be conducted with less labor intensive and less expensive methods such as differential scanning calorimetry (DSC) and TGA. 

NIRA provides a non-destructive alternative to differential scanning calorimetry for the determination of polymorphic forms of drugs, e.g. the polymorphic forms of caffeine. NIRA has also been used to determine optical purity. While the pure opposite enantiomers of a substance have identical NIR spectra, mixing two... 

A H (Ta20g, cr, 298.15 K) values show scatter due to uncertainties concerning the polymorphic state of the sample and/or the incomplete specification of sample purity ( ). The reported values for A H CTagOg, cr, 298.15 K) based on bomb calorimetry studies are as follows ... 

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