Preparation And Application Of Novel Stationary Phases Containing Amino Groups For Different Chromatography Mode

Generally, the separation of small molecules in chromatography is mainly based on single mode chromatography, such as hydrophilic interaction chromatography (HILIC) for the separation of polar compounds, while reversed-phase (RP) chromatography for the separation of non-polar or weak polar compounds. However, some complex samples of pharmacology, environment and food are often mixtures of compounds with different properties, which cannot be separated efficiently on the single mode stationary phase. Lately mixed-mode chromatography has been shown to be a flexible and versatile method for the simultaneous separation of highly mixed classes of analytes. Amino column, a typical hydrophilic interaction stationary phase, is one of the most widely used stationary phase for polar compounds which shows good separation efficiency at the same time. Based on these considerations, three mixed-mode stationary phases containing amino group were prepared in this paper. Moreover, their separation performance and mechanism were studied in both HILIC and RP mode.The contents are as follows:1. A new silica stationary phase containing primary amino, quaternary amino and imidogen groups was prepared, and its successful synthesis was confirmed by infrared spectra, element analysis and zeta potential. This new stationary phase showed both HILIC and RP characteristics.The effects of the water content, pH and salt concentration of mobile phase on the retention time of test compounds in highly aqueous eluents and highly ACN eluents were investigated respectively to evaluate the HILIC and RP features of new column. The separations of nucleosides under HILIC mode and sulfanilamides under RP mode were evaluated. It also offered us a new method to remove the interferences of other kinds of benzoic series while aromatic acids as target compound.2. Two kinds of stationary phases, cyclo cystine stationary phase[Sil-(Cys)2] and cysteine stationary phase(Sil-Cys), were prepared and these two proposed material were characterized by infrared spectra and element analysis which proved successful synthesis of two new column. Ellman reagent was used to quantity the thiol on the surface of silica. The effects of the water content, pH and salt concentration of mobile phase on the retention time of test compounds in HILIC mode and RP mode were investigated respectively to evaluate and compare the retention behavior/mechanism of these two synthesized stationary phases. These two new material showed good separation efficiency on five sulfonamides in both HILIC mode and RP mode.It could also separate seven aromatic acids efficiently in HILIC mode.