羧基甜菜碱型亲水作用色谱柱的制备及性能研究

以甲基丙烯酰氧乙基二甲基乙酸铵(CBMA)为功能单体,利用表面引发原子转移自由基聚合(Surface-initiated atom transfer radical polymerization, SI-ATRP)技术,将CBMA接枝到硅胶表面,得到接枝聚合物CBMA的亲水作用色谱固定相(Silica-CBMA).通过改变SI-ATRP反应体系中单体的浓度,制备了3种不同接枝量的亲水作用色谱固定相.考察了Silica-CBMA固定相对有机酸类化合物的分离性能以及流动相中pH值、盐浓度、水含量等因素对溶质保留行为的影响.结果表明,在亲水作用色谱模式下,Silica-CBMA固定相对有机酸类化合物的分离是离子交换作用与亲水作用的混合色谱模式.流动相中盐浓度增大,溶质保留减弱,符合离子交换作用特征;固定相和溶质的离子化程度受流动相pH值影响较大,pH值增大,溶质保留增强;而溶质的保留时间随流动相水含量增加而降低则是典型的亲水作用色谱特征.使用自制Silica-CBMA柱,建立了芦丁片中维生素C、芦丁含量的亲水作用色谱测定方法,操作方法简单,为强极性样品的分离测定提供了新方法.

Preparation of Carboxybetaine-based Hydrophilic Interaction Chromatographic Column and Its Performance Exploration

2-(Dimethylamino)ethyl methacrylate and sodium monochloroacetate were employed to synthesize 2-(Methacryloyloxy)ethyl] dimethyl ammonium acetate (CBMA) functional monomer.CBMA was grafted on the surface of silica by surface initiated atom transfer radical polymerization (SI-ATRP) to obtain silica-CBMA hydrophilic interaction stationary phase.Three silica-CBMA stationary phases with different grafted density of CBMA monomer were synthesized in SI-ATRP progress by changing the concentration of CBMA under the same conditions.The ability to separate organic acid compounds of the synthesized silica-CBMA stationary phases was evaluated under different conditions, including effects of pH value, salt concentration and content of water of mobile phase on retention of solutes.The results showed that the stationary phases could effectively separate organic acid compounds in HILIC mode, which followed a mixed mode of chromatography of ion exchange and hydrophilic interaction.The retention of solutes decreased with the increases of salt concentration of mobile phase, which consistent with the characteristics of ion exchange;the pH value of mobile phase had significant influence on ionization of the stationary phase and solutes, i.e., the retention of solutes increased as the increasing of pH value of mobile phase.However, the retention of solutes decreased with the increasing of the content of water in mobile phase, which was the typical characteristic of HILIC.The method of hydrophilic interaction chromatography combined with silica-CBMA stationary phases could conveniently determinate the content of vitamin C and rutin in rutin tablets, providing a new method for the separation and determination of strong polar samples.