10.1021/cg100152c.s004 Sekai Iwama Sekai Iwama Masahiro Horiguchi Masahiro Horiguchi Hiroyasu Sato Hiroyasu Sato Yoshiaki Uchida Yoshiaki Uchida Hiroki Takahashi Hiroki Takahashi Hirohito Tsue Hirohito Tsue Rui Tamura Rui Tamura Observation of the Preferential Enrichment Phenomenon for Essential α-Amino Acids with a Racemic Crystal Structure American Chemical Society 2010 alanine attenuated crystallization conditions surface Amino sample concentration acid crystal shape enantiomerically basis characterization mechanism Essential leucine racemic solvent reflection force microscopy observation solubility iii ii polymorphic transition analysis Racemic Crystal StructureThe iv Preferential Enrichment Phenomenon spectroscopy Acid enrichment phenomenon 2010-06-02 00:00:00 Dataset https://acs.figshare.com/articles/dataset/Observation_of_the_Preferential_Enrichment_Phenomenon_for_Essential_Amino_Acids_with_a_Racemic_Crystal_Structure/2764969 The preferential enrichment phenomenon has been observed for two neutral α-amino acids, leucine and alanine, by applying kinetic crystallization conditions using high concentrations and appropriate solvents. The mechanism of preferential enrichment of leucine and alanine is proposed on the basis of (i) the difference in solubility between the racemic and enantiomerically pure samples, (ii) the observation of polymorphic transition during crystallization by in situ attenuated total reflection infrared spectroscopy, (iii) the characterization of deposited crystals by X-ray crystallographic analysis, and (iv) the optical microscopic or atomic force microscopy observation of the crystal shape or surface, respectively.