Department of Chemistry, State Key Laboratory of Applied Organic Chemistry, Lanzhou University, South Road of Tianshui, 222, Departm, Lanzhou 730000, China.
Department of Chemistry, State Key Laboratory of Applied Organic Chemistry, Lanzhou University, South Road of Tianshui, 222, Departm, Lanzhou 730000, China.
J Chromatogr A. 2022 May 10;1670:462943. doi: 10.1016/j.chroma.2022.462943. Epub 2022 Mar 13.
Chiral covalent organic frameworks (CCOFs) have recently exhibited particularly promising potential as effective chiral stationary phases (CSPs) for open tubular capillary electrochromatography (OT-CEC) enantioseparation. However, it remains difficult to synthesis of CCOFs and preparation of CCOFs coated capillary under mild reaction conditions. In this work, we designed and fabricated a CCOF (CB-DA-COF) with high chemical stability and high specific surface area at room temperature. Then, through one-step in situ growth method, the chiral CB-DA-COF coated capillary was fabricated at room temperature for the first time. This method requires neither pre-modification to the capillary by organic molecular building units nor harsh reaction conditions, and the preparation time of the CCOF coating was significantly shortened (within 2 h). This chiral CB-DA-COF coated capillary showed excellent enantioseparation ability and stability. Under optimal conditions, rapid enantioseparation (within 5 min) could be achieved for six enantiomers including terbutaline, propranolol, phenylephrine, verapamil, norepinephrine and isoprenaline. And, no significant change was observed in enantioseparation efficiency after over 200 runs. The relative standard deviations (RSDs) of the analyte's migration time for intra-day, inter-day and column-to-column were within the range of 0.8-3.5% (n = 5), 1.5-4.7% (n = 3) and 4.3-8.3% (n = 3), respectively. In addition, the enantioseparation mechanism was studied, which indicated that binding energy between of enantiomers and chiral site were the main factors for enantioseparation.
手性共价有机框架（CCOFs）最近作为开管毛细管电色谱（OT-CEC）手性固定相（CSP）在对映体分离中表现出特别有前景的潜力。然而，在温和的反应条件下合成 CCOFs 和制备 CCOFs 涂覆毛细管仍然具有挑战性。在这项工作中，我们设计并制造了一种室温下具有高化学稳定性和高比表面积的 CCOF（CB-DA-COF）。然后，通过一步原位生长法，首次在室温下制备了手性 CB-DA-COF 涂覆毛细管。该方法既不需要有机分子构建单元对毛细管进行预修饰，也不需要苛刻的反应条件，并且显著缩短了 CCOF 涂层的制备时间（在 2 小时内）。这种手性 CB-DA-COF 涂覆毛细管表现出优异的对映体分离能力和稳定性。在最佳条件下，可在 5 分钟内实现包括特布他林、普萘洛尔、苯肾上腺素、维拉帕米、去甲肾上腺素和异丙肾上腺素在内的六种对映体的快速对映体分离。并且，在超过 200 次运行后，对映体分离效率没有明显变化。分析物迁移时间的日内、日间和柱间相对标准偏差（RSD）分别在 0.8-3.5%（n=5）、1.5-4.7%（n=3）和 4.3-8.3%（n=3）范围内。此外，研究了对映体分离机制，表明对映体和手性位点之间的结合能是对映体分离的主要因素。
