Metal–organic Framework Core–shell Materials:Preparation And Its Performance For High Performance Liquid Chromatography

High performance liquid chromatography（HPLC）is an important separation and analysis technique,widely used in chemistry,drug analysis,food safety testing,environmental detection and other fields.Chromatographic stationary phase is the core part of HPLC system,determining the separation efficiency of HPLC.Metal-organic frameworks（MOFs）is a new class of organic-inorganic hybrid porous crystal materials.The unique structures and excellent properties,such as porosity,high surface areas,as well as excellent chemical and thermal stability render it possesses good potential for the HPLC analysis as the new kind of stationary phase.The full text is divided into three chapters.The first chapter: This chapter is divided into three parts.In the first part,the research status of MOFs and their as the HPLC stationary phases were discussed.In the second part,the ionic liquids and their characteristic were introdued.In the third part,the innovation and starting point of the present work were briefly introduced.The second chapter: In this study,new cationic ionic liquids（ILs）1,3-bis（4-carboxybutyl）-imidazolium bromide（ILI）was designed and new MOFs nanocrystals ILI-01 was synthesized based on ILI.By further adjusting the growth cycles,ILI-01@SiO₂ core-shell chromatographic stationary phase were facilely fabricated.The new stationary phase was respectively characterized by Fourier transform infrared spectrometry,X-ray diffraction,scanning electron microscopy,thermogravimetric analysis,element analysis and surface area and porosity.The results demonstrate the ILI-01@SiO₂ core-shell stationary phase was successfully prepared.The last chapter: The new ILI-01@SiO₂ column was packed with the developed ILI-01@SiO₂ core-shell stationary phase.Because of the introduction of cationic imidazolium-based ILs ILI,the new stationary phase exhibits the retention mechanism of hydrophilic interaction liquid chromatography（HILIC）.Polar samples,such as amides,vitamins,nucleic acid bases and nucleosides,were utilized to investigate the performance of the ILI-01@SiO₂ column.Compared to the conventional aminosilica column,the new ILI-01@SiO₂ column displays high separation selectivity in a shorter separation time.Furthermore,the new ILI-01@Si O₂ column was also used for detection of illegal melamine addition in the baby formula.All the above results demonstrate the new ILI-01@Si O₂ core-shell stationary phase is of good potentials for high-selectivity separation the polar samples.