State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, China.
J Chromatogr A. 2011 Sep 2;1218(35):5987-94. doi: 10.1016/j.chroma.2011.04.023. Epub 2011 Apr 16.
An imidazoline was prepared by solvent-free microwave-assisted organic synthesis and immobilized on porous silica particles by polymerization. The resulting material was composed of both hydrophobic alkyl ester chains and hydrophilic imidazoline rings, which gave it both hydrophilic interaction and reversed-phase characteristics. The titration curve suggests that the new material has buffering capacity and acquires increasing positive charge over the pH range 9-4, and is "zwitterionic" in the upper part of this pH range. Through investigating the effect of column temperature, the water content, pH and ion strength of mobile phase on the retention time of polar compounds in highly organic eluents, it was found that the new material could be used as a hydrophilic interaction liquid chromatography (HILIC) stationary phase which involved a complex retention process consisting of partitioning, surface adsorption and electrostatic interactions. In addition, the retention behavior of aromatic compounds in different mobile phase conditions was also studied, which showed the new material mainly exhibited a partitioning mechanism in the reversed-phase liquid chromatography (RPLC) mode. The separation of six water-soluble vitamins and five aromatic compounds were achieved by using the new material in the HILIC and RPLC modes, respectively.
一种咪唑啉通过无溶剂微波辅助有机合成制备，并通过聚合固定在多孔硅粒子上。得到的材料由疏水性烷基酯链和亲水咪唑啉环组成，使其具有亲水相互作用和反相特性。滴定曲线表明，该新材料具有缓冲能力，并在 pH 值为 9-4 的范围内获得越来越多的正电荷，在该 pH 值范围的上半部分呈“两性离子”。通过考察柱温、流动相的含水量、pH 值和离子强度对高有机洗脱剂中极性化合物保留时间的影响，发现该新材料可用作亲水相互作用液相色谱（HILIC）固定相，其涉及由分配、表面吸附和静电相互作用组成的复杂保留过程。此外，还研究了芳香族化合物在不同流动相条件下的保留行为，表明该新材料在反相液相色谱（RPLC）模式下主要表现为分配机制。该新材料分别在 HILIC 和 RPLC 模式下实现了六种水溶性维生素和五种芳香族化合物的分离。
