| High performance liquid chromatography（HPLC）,as an efficient,rapid and novel separation and analysis technology,has been widely used in petrochemical industry,food hygiene,drug detection,environmental monitoring and many other fields.With the wide application of HPLC in various fields,people have put forward higher requirements for HPLC.The chromatographic column is the core of HPLC system,and the quality of the stationary phase filled with the particles directly determines the efficiency of chromatographic separation,so the preparation of high quality chromatographic stationary phase has always been the most active and popular research topic in the field of liquid chromatography.SiO2particles have the advantages of high mechanical strength,easy pore size control and easy surface chemical modification,so it is the most widely used stationary phase in HPLC.However,SiO2stationary phase has the disadvantages of narrow suitable p H range and easy trailing of chromatographic peaks of basic compounds,which makes it impossible to achieve efficient separation of a series of important compounds such as basic drugs,peptides and proteins.TiO2and ZrO2stationary phases can be used in the range of p H 1-14 and have high mechanical strength.Therefore,the modification of TiO2and ZrO2onto the surface of SiO2particles to prepare SiO2composite stationary phase can significantly improve the chemical stability of SiO2matrix stationary phase under alkaline conditions.However,because the structure of TiO2and ZrO2is not easy to control,the chromatographic separation efficiency of the prepared composite stationary phase is much lower than that of the silica gel stationary phase.Therefore,how to combine the good selectivity of TiO2and ZrO2materials with the advantages of high separation efficiency of porous SiO2materials has important research significance.This project mainly studies the preparation of SiO2@d SiO2@TiO2（SST）,SiO2@d SiO2@ZrO2（SSZ）and SiO2@d SiO2@ZrO2/TiO2（SSZT）composite particles based on core-shell structure and their application in the field of chromatographic separation.The content of this paper mainly includes the following aspects:（1）Preparation of SST stationary phase with high TiO2loading and its chromatographic separation performance.TiO2modified core-shell SiO2@d SiO2@TiO2（SST）microspheres were prepared by an improved sol-gel method using tetrabutyl titanate（TBOT）as titanium source and SiO2core-shell microspheres（SiO2@d SiO2）as carrier.Based on a detailed understanding of the hydrolysis process of TBOT,the effect of TBOT concentration on TiO2distribution on SiO2@d SiO2microspheres was explored.The experimental results show that the core-shell microspheres have the advantages of good monodispersity,high specific surface area,large pore size and high TiO2loading.Using ACN/H2O as the mobile phase,the column efficiency and separation of C18-modified SST-0.25were investigated.The results show that the separation efficiency and stability of the column are higher than those of the commercial TiO2column.TiO2modified core-shell SiO2@d SiO2@TiO2（SST）microspheres were prepared by an improved sol-gel method using tetrabutyl titanate（TBOT）as titanium source and SiO2core-shell microspheres（SiO2@d SiO2）as carrier.Based on a detailed understanding of the hydrolysis process of TBOT,the effect of TBOT concentration on TiO2distribution on SiO2@d SiO2microspheres was explored.The experimental results show that the core-shell microspheres have the advantages of good monodispersity,high specific surface area,large pore size and high TiO2loading.Using ACN/H2O as the mobile phase,the column efficiency and separation of C18-modified SST-0.25 were investigated.The results show that the separation efficiency and stability of the column are higher than those of the commercial TiO2column.（2）Preparation and chromatographic separation of SST stationary phase with adjustable and uniform TiO2shell thickness.Using SiO2core-shell microspheres as the carrier and TBOT as the titanium source,TiO2was modified into the pore of SiO2@d SiO2.Then,the TiO2nanoclusters filled in the pore were partially dissolved and transferred to the surface of SiO2@d SiO2to form TiO2layers with different thicknesses by Ostwald maturation.The core-shell SST with different TiO2thickness was derived by C18 and then used as stationary phase to investigate its chromatographic separation performance.The experimental results show that although the TiO2loading of SST particles prepared by this method does not increase,the number of TiO2nanoclusters that can be used to interact with the sample molecules is significantly increased,thus improving the chromatographic separation efficiency.（3）Preparation of core-shell SSZ composite particles and its application in HPLC.ZrO2was modified onto SiO2@d SiO2using SiO2core-shell microspheres as support and zirconium isopropanol（TPZr）as zirconium source.The effect of different dosage of TPZr on the distribution of ZrO2on SiO2core-shell spheres was investigated.The properties of SiO2@d SiO2@ZrO2（SSZ）composite microspheres were tested by a series of characterization methods.The results show that the core-shell SSZ composite microspheres have good monodispersion,large pore size,narrow particle size distribution range and uniform particle size,and are suitable for HPLC packing.The results of chromatographic separation experiments show that C18-SSZ bonded with C18 is very suitable for the separation of alkaline substances.（4）Preparation of SSZT core-shell stationary phase and its application in HPLC.A series of complexes with Zr/Ti ratios ranging from 0 to 100%were modified to the pores and surfaces of the core-shell particles using SiO2@d SiO2as the carrier.The crystal structures of the complexes with different Zr/Ti ratios,the pore size distribution and the particle morphology at a Zr/Ti ratio of 9:1 were tested.The preliminary experimental results show that the complex with different Zr/Ti ratio can be modified on the surface of SiO2@d SiO2particles by this method,and the composite stationary phase prepared by this method has good monodispersity and pore size greater than 10nm,which is suitable for HPLC stationary phase for chromatographic separation.The above experimental results show that the new composite stationary phase not only has large specific surface area,controllable pore structure and adjustable pore size,but also overcomes the shortcomings of poor chemical stability of SiO2filler and narrow p H application range.It has a broad application prospect in the field of high performance liquid chromatography.Figure[43]table[19]reference[151]... |
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