A study into first and second order thermal transitions of materials using Spectral-DSC
Thermal and spectral analysis is conducted routinely to characterise a large range of materials and compounds. However, tests are often conducted independently on separate samples where comparison between essentially the same material can provide conflicting results. Simultaneous thermal and spectral measurements have the advantage of being able to directly compare results using the same sample. A novel design of a simultaneous thermal and spectral technique is described along with application examples that highlight the benefits of this technique. The thermal analysis was conducted using Differential Scanning Calorimetry (DSC) and the in situ spectral analysis was conducted using a Fourier Transform Near Infrared (FT-NIR) spectrometer. Two examples are used to illustrate the versatility and potential advantages of the combined thermal and spectral method. Analysis of the first and second order transitions of polyethylene terephthalate (PET) is presented along with the pharmaceutical polymorphic conversion of carbamazepine from Form III to Form I through an isothermal hold at 160 °C.
KeywordsDifferential Scanning Calorimetry Carbamazepine Trigeminal Neuralgia Polymorphic Form Near Infrared Spectroscopy
The authors would like to thank the Technology Strategy Board (TSB), Bruker Optics UK, Mettler-Toledo UK and AstraZeneca for their support of the ADSC/NIR screening technique project (tf/Nov04/nano/00234).
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