A rapid and robust separation method based on the positively charged reversed-phase (PGRP) stationary phase was developed for selective separation of saponins and xanthones from the rhizomes of Anemarrhena asphodeloides (A. asphodeloides). In this work, the chromatographic performances of three PGRP stationary phases with different surface positive charge densities were systematically evaluated by studying hydrophobicity, effects of pH and buffer concentration of the mobile phase, ion-exchange capacity, etc. The PGRP stationary phase exhibited reversed-phase/anion-exchange mixed-mode properties. Then the retention behaviors of xanthones were investigated. A good retention of xanthones was obtained at high pH and xanthones were easily eluted at low pH. The pH is like an on–off switch on the PGRP stationary phase that controls the retention of xanthones. Finally, this PGRP material was successfully applied to the selective separation of saponins and xanthones from A. asphodeloides. The result demonstrated that neutral and ionic compounds, such as xanthones and saponins from the rhizomes of A. asphodeloides, were separated selectively by modulating both the density of surface charges in the PGRP stationary phase and the pH of the mobile phase.

中文翻译：

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通过调节C18键合固定相中的表面电荷密度，选择性地从知母二倍体的根茎中选择性分离黄嘌呤和皂苷

建立了一种基于正电荷反相固定相的快速，稳定的分离方法，用于从知母（A. asphodeloides）的根茎中选择性地分离皂苷和黄原酮。在这项工作中，通过研究疏水性，pH和流动相缓冲液浓度的影响，离子交换能力等，系统地评估了具有不同表面正电荷密度的三种PGRP固定相的色谱性能。PGRP固定相具有反相/阴离子交换混合模式特性。然后研究了氧杂蒽酮的保留行为。在高pH条件下获得了良好的ant吨酮保留，而在低pH值下很容易洗脱出ant吨酮。pH值就像是PGRP固定相上的一个开-关开关，用于控制氧杂蒽的保留。最终，这种PGRP材料成功地应用于从A. asphodeloides中选择性地分离出皂苷和氧杂蒽酮。结果表明，通过调节PGRP固定相中表面电荷的密度和流动相的pH值，可以选择性地分离中性和离子性化合物，例如来自A.倍体拟南芥的根茎中的氧杂蒽酮和皂苷。