色谱

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一种混合模式反相强阳离子交换色谱填料的制备及其保留机理

彭西甜1,王珏2,冯钰锜3   

  1. 1. 湖北省农业科学院农业质量标准与检测技术研究所
    2. 华东师范大学上海分子治疗与新药创新工程技术研究中心
    3. 武汉大学化学与分子科学学院分析科学研究中心
  • 收稿日期:2012-11-20 修回日期:2012-12-17 出版日期:2012-12-18 发布日期:2013-01-23
  • 通讯作者: 冯钰锜

Preparation and retention mechanism of a mixed-mode reverse-phase/strong-cationic-exchange packing

Xi-Tian PENG, ,Yuqi FENG   

  • Received:2012-11-20 Revised:2012-12-17 Online:2012-12-18 Published:2013-01-23
  • Contact: Yuqi FENG

摘要： 本文采用一种简单的“混合配体”方法，将辛基和磺酸基键合到了硅胶表面，制备了辛基-磺酸基共同键合硅胶（OSS）材料。通过元素分析和吸附容量对OSS材料进行表征，证明了辛基和磺酸基已经成功键合到了硅胶表面。将该OSS硅胶材料作为混合模式反相强阳离子交换（RP/SCX）固定相的填料，在反相色谱（RPLC）流动相条件下，采用几种碱性的探针分子，定量地研究了该固定相的混合模式RP/SCX保留机理。通过改变流动相中缓冲盐的浓度，考察了溶质保留因子和盐浓度的对数和倒数的关系，得到了几种碱性探针分子在该混合模式OSS固定相上的单点和两点保留机理的数学模型。对两种数学模型的方程进行线性拟合，结果表明两点保留机理更加符合实验的结果。此外，根据混合模式两点保留机理的数学方程，可以得到单一的疏水或离子交换作用力对总保留的影响，对混合模式色谱的实际分离应用可提供有价值的参考。

关键词: 保留机理, 反相强阳离子交换, 混合模式色谱, 数学模型

Abstract: A simple and efficient method was proposed for the preparation of octyl-sulfonic co-bonded silica (OSS) packing by the method of “mixed ligand”. The resulting OSS packing was characterized by elemental analysis (EI) and ion-exchange capacity to prove the successful immobilization of octyl and sulfonic groups on the surface of silica gel. Then the retention mechanism of several basic analytes on the developed OSS phases was evaluated under reverse-phase liquid chromatography (RPLC) mobile phase conditions. The results indicated that the OSS stationary phases demonstrated a mixed-mode reverse-phase/strong-cationic-exchange (RP/SCX) retention mechanism and ion-exchange interaction maybe dominate the retention of basic analytes. By changing the salt concentration of mobile phase, the one-site and two-site mixed-mode retention models of several basic analytes on the OSS phases were obtained by investigating the logarithm and reciprocal relationships of retention factors and salt concentrations. On the basis of the linear fitting of the two mathematical equations of retention models, the experimental results demonstrated that the two-site model was more suitable for the description of the retention mechanism of basic analytes on the OSS phases. Furthermore, the individual RP or SCX contribution to total retention was obtained according to the mathematical equations of two-site retention mechanism, which can provide some valuable guidance for the separation of complex samples.

Key words: mathematic model, retention mechanism, reverse phase/strong cationic exchange, mixed-mode chromatography