Study On The Preparation, Evaluation And Application Of Reversed Phase/Strong Cationic Exchange Mixed-mode Chromatographic Stationary Phase

High performance liquid chromatography(HPLC) was the most widely used separation analysis instrument. Chromatographic stationary phase was one of the core of the separation system. Mixed-mode chromatography can provide multiple retention mechanism and the better separation of complex samples. So more and more attentions were devoted to the mixed-mode chromatography in recent years.A mixed-mode reversed-phase/strong-cationic exchange chromatographic stationary phase was prepared by bonding and oxidizing octadecyltrichlorosilane(OTS) and trimethoxysilylpropanethiol(MPS) to the surface of activated silica. The chromatographic stationary phase was characterized by elemental analysis and infrared spectra. The results indicated that -C18 group and -SO3H group were bonded to the surface of silica in a mole ratio of 2:5. The retention behaviors of hydrophobic, hydrophilic and ionic samples and the separation of complex samples were studied. The results showed that the mixed-mode chromatographic stationary phase could display the features of reversed phase chromatography, hydrophilic chromatography, ion exchange chromatography and existed dual retention mechanism to ionic samples as well. Finally, six kinds of acidic, basic and neutral samples were separated successfully.By changing the proportion of OTS and MPS, we have prepared three kinds of mixed-mode chromatographic stationary phase and analyzed by elemental analysis, evaluation of hydrophobic and measurement of ion exchange capacity. The results showed that with the increase of the C18 and the decrease of the SO3H, the more carbon content, stronger hydrophobicity, lower ion exchange capacity.Using the mixed-mode chromatographic stationary phase analyzed p-phenylene-diamine in hair dye. The results showed that mixed-mode chromatographic station-ary phase can provide accurate, reproducible results.The peptide fragment of BSA was analyzed by mixed-mode chromatographic stationary phase and optimized the chromatographic condition. The results were compared with C18 and SCX column, the results showed the unique separation selectivity of mixed-mode chromatographic stationary phase.