Latvian Institute of Organic Synthesis, 21 Aizkraukles Street, LV-1006 Riga, Latvia.
Latvian Institute of Organic Synthesis, 21 Aizkraukles Street, LV-1006 Riga, Latvia.
J Chromatogr A. 2020 Jul 5;1622:461152. doi: 10.1016/j.chroma.2020.461152. Epub 2020 Apr 28.
The chiral separations of small peptides is an important challenge in the biological and medical sciences, because different stereoisomers of chiral drugs can often possess different pharmacological, pharmacokinetic, and/or toxicological activities. Commercially available crown ether chiral stationary phases based on S-(3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 (CROWNPAK CR-I (+)) and (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (ChiroSil RCA (+)) have been successfully used for separating enantiomers of various racemic compounds containing primary amino groups. In this investigation, enantioresolution of more complex model analyte - tetrapeptide Tyr-Arg-Phe-Lys-NH, has been reported on crown ether chiral stationary phases. Organic and acidic modifier content in aqueous mobile phase was tested. All Tyr-Arg-Phe-Lys-NH stereoisomers showed U-shaped retention plots, based on ACN content in mobile phase. Increased retention of tetrapeptide stereoisomers was observed at low (<35%) and at high (>70%) acetonitrile content in the mobile phase, indicating that different separation mechanisms are most likely involved. As a result, baseline separation of all eight tetrapeptide enantiomer pairs was achieved under isocratic elution mode on both chiral columns.
手性小肽的拆分是生物和医学科学中的一个重要挑战，因为手性药物的不同对映异构体往往具有不同的药理学、药代动力学和/或毒理学活性。基于 S-（3,3'-二苯基-1,1'-联萘基）-20-冠-6（CROWNPAK CR-I（+））和（+）-（18-冠-6）-2,3,11,12-四羧酸（ChiroSil RCA（+））的商业 Crown Ether 手性固定相已成功用于拆分含有伯氨基的各种外消旋化合物的对映异构体。在这项研究中，报道了在 Crown Ether 手性固定相上拆分更复杂的模型分析物 - 四肽 Tyr-Arg-Phe-Lys-NH 的对映体拆分。测试了水相中的有机和酸性修饰剂含量。所有 Tyr-Arg-Phe-Lys-NH 对映异构体都表现出基于流动相 ACN 含量的 U 形保留曲线。在流动相中 ACN 含量较低（<35%）和较高（>70%）时，观察到四肽对映异构体的保留增加，这表明可能涉及不同的分离机制。结果，在两种手性柱上均采用等度洗脱模式实现了所有 8 对对映体的基线分离。
