Monitoring phase transitions of crystals in-line

• Here two rather new PAT tools (ultrasound and 3D ORM techniques) are tested.
• Evaluation the response of PAT tools concerning the phase transition in 3 case studies.
• The ultrasound technique shows a clear response to phase transitions in 2 of the case studies.
• The 3D ORM can monitor the phase transition of all case studies to be seen in clear changes in the measured lengths.

An online control in production of crystalline substances with respect to their morphology or a solvent mediated phase transfer is of key importance in many industries. Here two rather new PAT tools are tested. Monitoring of solvent mediated phase transition by ultrasound (single frequency) and 3D optical reflectance measurement (ORM) (advanced particle analyzing system (APAS)) is evaluated based on case studies with sulfathiazole, magnesium sulfate and di-sodium tetraborate. The achieved results by the in-line PAT tools are proven by optical microscopy. The different solvates and polymorphic forms could be detected by the use of ultrasound (single frequency) and 3D ORM (APAS) techniques, however, the application of these techniques does not work in all cases, but always at least one is working. There are limitations with respect to the nature of the examined substances.

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