Nucleation and crystal growth of alpha-glycine

Secondary nucleation is widely present in crystallisation processes and it is often relied upon to attain desirable critical quality attributes of crystalline products, such as polymorphic form and crystal size distribution. This is particularly the case in continuous crystallisation, where a good control of secondary nucleation can be crucial in order to achieve and maintain steady state operation.
This work utilises rapid, small-scale experiments in agitated vials with in-situ imaging for crystal counting and sizing (using the Crystalline platform), to quantify nucleation and crystal growth kinetics of α-glycine across a range of supersaturations in aqueous solutions under isothermal conditions. Both seeded and unseeded crystallisation experiments were conducted.
It was found that secondary nucleation and crystal growth rates determined from the same vials show a close correlation across the whole range of supersaturations investigated, which suggest a close relationship between the mechanisms of shear induced secondary nucleation and crystal growth in this system.