Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic.
J Sep Sci. 2010 Mar;33(6-7):841-52. doi: 10.1002/jssc.200900678.
We investigated the retention of phenolic acid and flavone antioxidants on five polar columns in buffered aqueous ACN mobile phases. All columns show mixed retention mechanism: RP in highly aqueous mobile phases and normal phase (hydrophilic interaction LC, HILIC) in mobile phases with high concentration of ACN. The Silica Hydride and the ZIC HILIC sulfobetaine zwitterionic columns show rather limited retention in the RP mode. The Luna HILIC column shows higher retention in both the HILIC and the RP modes in comparison to the PEG and DIOL columns. We characterized the selectivity of various HILIC systems using linear solvation energy relationship model with molecular structure descriptors characterizing selective molecular size, dipole-dipole and proton-donor/proton-acceptor interactions and we investigated the effects of the mobile phase composition on the linear solvation energy relationship characteristics of the separation phase systems to select suitable conditions for orthogonal HILIC separations in combination with RP systems. Dual retention mechanism offers possibilities for using complementary selectivity in the HILIC and the RP modes for sequential 2-D separations of natural antioxidants on a single Luna HILIC column. Column equilibration time of 15 min between alternating RP and HILIC gradient runs is sufficient for reproducible results.
我们研究了在缓冲的含水 ACN 流动相中五种极性柱上酚酸和黄酮类抗氧化剂的保留情况。所有柱子都显示出混合保留机制：在高水相流动相中为反相（RP），在高 ACN 浓度的流动相中为正相（亲水相互作用 LC，HILIC）。Silica Hydride 和 ZIC HILIC 磺丁基甜菜碱两性离子柱在 RP 模式下的保留性相当有限。与 PEG 和 DIOL 柱相比，Luna HILIC 柱在 HILIC 和 RP 模式下均显示出更高的保留性。我们使用线性溶剂化能量关系模型和分子结构描述符来表征各种 HILIC 系统的选择性，这些描述符表征了选择性分子大小、偶极-偶极和质子供体/质子受体相互作用，我们研究了流动相组成对分离相系统线性溶剂化能量关系特征的影响，以选择合适的条件，结合 RP 系统进行正交 HILIC 分离。双重保留机制为在 HILIC 和 RP 模式下使用互补选择性提供了可能性，以便在单个 Luna HILIC 柱上对天然抗氧化剂进行顺序二维分离。在交替的 RP 和 HILIC 梯度运行之间，柱子的平衡时间为 15 分钟，足以获得可重复的结果。
