Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, Japan.
Department of Applied Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, Japan.
J Chromatogr A. 2022 Aug 16;1677:463294. doi: 10.1016/j.chroma.2022.463294. Epub 2022 Jun 30.
Considering the vulnerability of silica gel to alkaline mobile phases, a highly alkaline stable stationary phase for HPLC is required to separate basic compounds with high separation efficiency. To address this issue, we have developed a high alkaline stable packing material (CaCO-PMAcO) based on mesoporous calcium carbonate microspheres modified with poly(maleic acid-alt-1-octadecene). In this study, we report further investigation of the separation performance of CaCO-PMAcO column by systematically evaluating the effects of particle size and chromatographic conditions. Based on the theory of the van Deemter equation, the separation efficiency was related to the size of CaCO-PMAcO particles (2.9 - 5.7 µm). The evaluation of thermodynamics of retention by changing the column temperature from 20 °C to 45 °C implied that the retention mode was dominated by hydrophobic interaction associated with the exothermic enthalpy changes (-11.1 to -12.5 kJ/mol). The results of column selectivity tests revealed that the CaCO-PMAcO column had hydrophobic selectivity comparable to C silica gel columns (α; CaCO-PMAcO column: 1.53, C column: 1.69), and higher shape/steric selectivity (α; CaCO-PMAcO column: 1.56, C column: 0.955). In practice, the CaCO-PMAcO column could be applied to the separation of not only alkylbenzenes and polycyclic aromatic hydrocarbons, but also to basic tricyclic antidepressants by using an alkaline mobile phase (pH 12).
考虑到硅胶对碱性流动相的脆弱性，需要一种高碱性稳定的 HPLC 固定相，以实现高分离效率分离碱性化合物。为了解决这个问题，我们开发了一种基于介孔碳酸钙微球的高碱性稳定填充材料（CaCO-PMAcO），该微球经过聚（马来酸-alt-1-十八烯）改性。在本研究中，我们通过系统评估粒径和色谱条件的影响，进一步研究了 CaCO-PMAcO 柱的分离性能。根据范德姆方程的理论，分离效率与 CaCO-PMAcO 颗粒的大小（2.9-5.7 µm）有关。通过改变柱温从 20°C 到 45°C 评估保留的热力学表明，保留模式主要由与放热焓变化（-11.1 至-12.5 kJ/mol）相关的疏水性相互作用决定。柱选择性测试的结果表明，CaCO-PMAcO 柱具有与 C 硅胶柱相当的疏水性选择性（α；CaCO-PMAcO 柱：1.53，C 柱：1.69），以及更高的形状/空间选择性（α；CaCO-PMAcO 柱：1.56，C 柱：0.955）。在实际应用中，CaCO-PMAcO 柱不仅可以用于分离烷基苯和多环芳烃，还可以在碱性流动相（pH 12）下用于分离碱性三环抗抑郁药。
