Synthesis Of Mesoporous Silica Spheres And Application In High Performance Liquid Chromatography

With the wide application of high performance liquid chromatography(HPLC)in the fields of chemical industry,medicine,environment and so on,people put forward higher requirements for HPLC.Chromatographic packing is the core of HPLC.It is the most critical part of chromatographic research.Mesoporous silica microsphere is,by far,the most widely used substrate for HPLC stationary.New materials such as small silica particle and organic-inorganic hybrid silica have become the new direction of liquid chromatography packings development.In this paper,we studied the synthesis of a new kind of mesoporous silica microspheres with a small size of 2 ?m and organic-inorganic hybrid mesoporous silica microspheres,and their application in high performance liquid chromatography,Sub-2 ?m large-pore monodispersed mesoporous silica spheres(MMSS)were synthesized by using non-ionic surfactants of dodecylamine(DDA)as template,dodecylamine polyoxyethylene ether(AC1210)as pore-expanding agent through an alkali-catalyzed silica sol-gel technique.The synthesized sub-2 ?m monodispersed mesoporous silica microspheres were successfully functionalized by dimethyloctadecylchlorosilane and used as reversed-phase chromatographic packing in ultra performance liquid chromatography(UPLC).During the process of sol-gel,methanol-H2O volume ratio and reaction temperature on morphology were researched in detail.During the process of hydrothermal post-treatment,Aging temperature and aging time on pore size distributions were researched in detail.Methanol-H2O volume ratio between 2.4:1 and 4:1 is suitable to synthesis MMSS with particle size of 0.4-2 ?m.By adjusting the aging temperature and time,the average pore size of MMSS could be enlarged to 11 nm from 4.4 nm.The kinetics and reverse phase retention behavior of the prepared C18 column were evaluated.Refer to the experimental conditions for the synthesis of MMSS,Vinyl organic-inorganic hybrid mesoporous silica microspheres were prepared through co-condensation method by using vinyltrimethoxysilane(VTMS)and tetraethoxysilane(TEOS)as the silica source,the effect of TEOS/VTMS ratio on morphology and pore size of hybrid silica were investigated.In the process of hydrothermal treatment,we used AC 1210 as pore expanding agent,and combined with a certain concentration of ammonium fluoride to further expand the pore size of hybrid material.Finally,the synthesis of vinyl hybrid material was prepared by using TEOS/VTMS = 5:1.The obtained 2.3 ?m vinyl hybrid silica spheres were aging at 100? for 12 h.We synthesised the vinyl organic-inorganic hybrid mesoporous silica microspheres with a surface area of 351 m2/g and a pore size of 7.2 nm.The prepared hybrid silica microspheres were functionalized by cysteine through thiol-ene click chemistry and then used as hydrophilic chromatography stationary phase.The retention behaviors of polar compounds in the hydrophilic mode were studied.