Crystallization which plays an important role in the separation and purification of high purity compounds

is a traditional separation and purification technology widely used in chemical

pharmaceutical and other fields.The spectral process analysis technology based on the concept of quality by design provides an efficient and intelligent support for the monitoring

feedback and control of crystallization process.In this paper

applications of several process analysis technologies

such as attenuated total reflection Fourier transform infrared spectroscopy

Raman spectroscopy

near infrared spectroscopy and focused beam reflectance measurement are reviewed.The status

advantages and disadvantages of the above technologies are systematically summarized

and their future development trends are prospected

in order to provide an effective reference for the on line monitoring of crystallization process.