材料期刊网

采用“点击化学”的合成方法制备了一种混合配体的辛基-羧基共同键合硅胶（OCS）材料，经元素分析和红外光谱表征，证明了辛基和羧基官能团均已成功键合到硅胶表面。将其作为混合模式反相弱阳离子交换（ RP / WCX）的固定相填料，以3种同系物阳离子表面活性剂作为探针分子，定量研究了该固定相的混合模式保留机理，考察了溶质保留因子与盐浓度和溶质亚甲基数目的关系，验证了混合模式固定相的单点和两点保留机理的数学模型，并进一步将其应用于一系列标准碱性混合物的分离。结果表明：两点保留机理更加符合实验的结果；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提供了有价值的参考。本文建立了反相弱阳离子交换混合模式 OCS 固定相的保留机理的定量模型，并证明了该固定相在碱性化合物的分离中具有很大的应用前景。

A“mixed ligand”octyl-carboxylic co-bonded silica(OCS)packing was prepared by the method of“ click chemistry”. The resulting OCS packing was characterized by elemental analysis( EI)and Fourier transform infrared spectroscopy( FT-IR) to prove the successful immobilization of octyl and carboxylic groups on the surface of silica gel. Then the mixed-mode reversed-phase / weak-cationic-exchange( RP / WCX)retention mechanism of the OCS packing was quantitatively probed by studying the retention factors of a homologous series of three cat-ionic surfactants on the mixed-mode stationary phase column as a function of the ammonium concentration in the eluent or the number of methylene groups in the solute. The one-site and two-site mixed-mode retention models of the three cationic surfactants on the OCS phases were studied by investigating the logarithm and reciprocal relationships of retention factors and salt concentrations,demonstrating that the two-site model was more suitable for the description of the retention mechanism of the three cationic surfactants on the OCS phases. Furthermore,the individual RP or WCX contribution to total retention was obtained according to the mathemati-cal equations of two-site retention mechanism,which can provide some valuable guidance for the separation of real samples. This study developed the qualitative model of retention mecha-nism of the mixed-mode OCS packing,and a series of standard basic mixtures were well sepa-rated on the OCS packing,demonstrating the great application potential of OCS packing for the separation of various basic compounds.