Crystallization of β-Glycine from Water Via Monodisperse Droplet Evaporation

There is great potential for technological advancement in the pharmaceutical and food industries as a result of data from modern research on crystallization. Properties of particles and crystals, such as morphology and polymorphism, have substantial effects on the performance of the final product. The ability to control these properties and understand their result as a function of the underlying chemistry and the formation process is a modern challenge.  Moreover, the ability to control these properties during particle formation rather than manipulating them via post-processing steps allows for improved processing. This research examines the formation of crystalline glycine, the smallest amino acid, through monodisperse droplet evaporation.  Specifically, this work demonstrates the effects of different solvents combined on the morphologies and polymorphs of glycine that are produced.

Previous research suggests that the metastable alpha polymorph forms by crystallization of glycine from pure water solutions. Only when more complex chemistry is used is the beta polymorph of glycine produced. Some such methods that have formed the beta polymorph include crystallization from an organic cosolvent, a change in pH, crystallization through freeze drying, and crystallization in polymer nanorods. Contrary to past results, this work demonstrates the production of beta glycine from pure water solutions by evaporating small droplets.  Additionally, this research also presents the resulting morphologies of glycine using this technique from pure water, water/acetone solvent mixtures and water/ethanol solvent mixtures obtained by scanning electron microscopy (SEM).