Probing the Mechanisms Underlying Electrolyte-Assisted Nucleation Enhancement of dl-Alanine

The effects of common electrolytes (including inorganic acids, bases, and salts) on dl -alanine nucleation in aqueous solutions have been systematically investigated via measurement of nucleation induction times. It is observed that all the electrolytes examined in this study considerably shorten the induction times, suggesting that they greatly enhance dl -alanine nucleation. It is hypothesized that, in solution, an electrolyte assists the formation of the head-to-tail chains of dl -alanine molecules. Such head-to-tail chains, structurally matching dl -alanine crystal packing, act as favorable precursors for dl -alanine nucleation and play a great role in enhancing the nucleation, highlighting the importance of prenucleation phenomena.