| chemical separation and can be normally prepared by attaching specific ligands to the surface of solid support. Porous silica supports, with the advantages of high mechanical strength, controllable morphology, good biocompatibility, abundant surface reactive groups, are ideal matrix materials of separation carriers. Silica-based separation carriers, which are functionalized with organic moleculars, have extensive application perspective in chromatographic resolution, scavenging pollutants and industrial catalysis. Therefore, pharmaceutical analysis area has been focusing on developing new functional methods of silica and their application in pharmaceutical industry. From the perspective of functionalization of silica matrix, in this thesis, preparation, characterization and application of polar embedded alkyl phases based on porous silica matrix were studied; highly deactivated octadecyl bonded silica packing was prepared and its chromatographic performance was evaluated; a new technology of functionalization for the preparation of mercaptopropyl ligands grafted porous silica was developed; preparation, characterization and application of efficient absorbents of palladium based on porous magnetite/silica matrix were studied. Some proposals such as developing environmental benign and economic technology for synthesis of materials, exploiting the application area of silica-based separation carriers, designing and preparation of high performance separation carriers with specific application, were attempted originally. The main research results are listed as follows:1,Four kinds of polar embedded octadecyl (C18) phases, C18 amide, C18 urea, C18 ether and C18 carbamate, were prepared successfully by single-step silylation process using porous silica microspheres as matrix. The retention mechanism of four kinds of polar embedded C18 phases were studied by using the four components of dihydroergotoxine as a model of separation. And the baseline separation of the four components was achieved on C18 amide phase under a neutral mobile phase for the first time. In comparison with traditional methods, which triethylamine was added to the mobile phase as modifier, the method described here offer several advantages such as improving the separation performance of basic compounds and prolonging the service-time of HPLC column. The results showed that the stationary phase could be efficiently used for the separation of basic compounds under a neutral mobile phase. 2,A novel gas-solid reaction method for the preparation of highly deactivated octadecyl (C18) bonded silica packing was developed independently. By this method, the highly deactivated C18 bonded silica packing can be obtained conveniently by high temperature treatment of the mixture of C18 bonded silica and endcapping reagent of hexamethyldisilazane (HMDS) added to an autoclave under the protection of the inert gas. Effects of reaction temperature, HMDS amount, reaction time and times of endcapping on endcapping reaction were systematically studied. Tailing factor value of amitriptyline on endcapped C18 silica by gas-solid phase procedure under an optimal reaction condition, endcapped C18 silica by liquid-phase method, two kinds of commercial C18 bonded silica Agilent Zorbax SB-C18 and Kromasil C18 were 1.30, 5.35, 2.04 and 1.91, respectively, under pH 7.0 mobile phase. This shows that the undesirable silanol of C18 bonded silica has been deactivated successfully by gas-solid phase reaction and the performance of endcapped product had surpassed commercial products. In comparison with liquid-phase procedure, this method is simple, effective and a complete endcapping and good reproducibility of inter-batch preparation can be obtained.3,A novel gas-solid reaction method for the preparation of chemically bonded silica packing was developed independently, which involves the modification of porous silica via gas-solid reaction procedure carried out in an autoclave with trifunctionalγ-mercaptopropyltrimethoxysilane,γ-merecaptopropyltriethoxysilane and bifunctionalγ-mercaptopropyldimethoxymethylsilane, respectively. Effects of reaction temperature, amount of silanes reagent, reaction time, catalyst and reaction times on surface coverage of mercaptopropyl group were systematically studied. Mercaptopropyl surface coverage of MPTMS, MPTES and MPDMMS modified silica by gas-solid reaction method under an optimal reaction condition were 2.76,2.53 and 2.57μmol·m-2, respectively. However, MPTMS, MPTES and MPDMMS modified silica by liquid-phase procedure only show 1.90,1.08 and 1.60μmol·m-2 surface coverage of mercaptopropyl ligands. The bonding mode and pore structure of the resultant products were characterized by FT-IR, solid state 13C and 29Si nuclear magnetic resonance, elemental analysis, TGA, nitrogen adsorption-desorption, respectively. The thiol functional silica was efficient for the removal of Pd(II) ions. In addition, glycidoxypropyl functional silica was also prepared via gas-solid phase silylation reaction and the effect of reaction temperature on surface coverage of glycidoxypropyl groups was inspected. More importantly, gas-solid reaction method reduces the cost of production of chemically bonded silica phases packing and the intensity of physical work with a simple post treatment. Therefore, this method described here offer an economic and environmental benign approach for mass production of chemically bonded silica packing.4,Magnetically recoverable mercaptopropyl functional materials of combining the advantages of porous silica and magnetic particles were prepared successfully by vapor phase deposition using uniform porous magnetite/silica microspheres (MSM) as matrix for the first time. As-prepared mercaptopropyl functional materials have higher surface coverage and their separation in liquid media can be controlled well by magnetic fields. Palladium adsorption on thiol functionalized absorbents is a fast and efficient process and very low levels of residual Pd (II) ions content can be achieved. Langmuir isotherms have been fitted to experimental palladium adsorption data very well, palladium (II) loaded the mercaptopropylsilanes modified absorbents can be separated quickly using an external magnetic field.
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