Preparation Of Titania Stationary Phase And Its Modified Performance Evaluation

Along with the rapid development of modern science and technology, there is an increasing demand in the industry of chemistry, biology and medicine for advanced separation technology. Complex samples can not be well separated on silica based columns under harsh separation conditions (such as higher or lower pH). Researchers, in order to find the ideal alternative substrates, turn to titanium oxide, zirconium oxide, aluminum oxide, cerium oxide and other inorganic oxides. Titanium dioxide, a new chromatographic packing material with stable physical and chemical properties, exhibits excellent separation ability in biological macromolecules, polysaccharides, nucleotides and other substances separation. And when it is used to separate basic substance, it exhibits better separation effects than silica does.This thesis begins with the preparation for titanium dioxide hydrosol. Titanium tetrachloride and tetrabutyl titanate, common sources of titanium, were used to obtained titanium dioxide hydrosol by a hydrolysis process. First, a small amount of titanium tetrachloride was added dropwise to a flask containing ice water, the reaction was carried out in the ice-water bath to form a primary titanium hydrosol. Then titanium tetrabutoxid was added dropwise to primary sol, and after a complex process, there formed the synthesis titanium hydrosol particles with a small size distribution about 20-30nm. The forming conditions of titania particles were determined by discussing separately the factors of the reaction temperature, heating time, the adjusted pH value and solid content of aqueous titania sols. Then orthogonal design experiments on the above factors were made to analyze the influence among the synthesis factors. Depending on SEM, HRTEM, XRD and other characterization, the formation mechanism of aqueous titania sols was discussed.An appropriate amount of urea and formaldehyde were added to self-made titanium dioxide hydrosol. By using the method of polymerization-induced colloid aggregation (PICA), at a certain pH and temperature, titanium dioxide/urea-formaldehyde microspheres were synthesized. The final product was obtained after a calcination process. By adjusting such factors as solid content of sols, pH value of the reaction, polymerization temperature and urea-formaldehyde addition ratio, we discussed the effects of various factors on titania composite microspheres preparation. After the synthesized titania composite microspheres were got to programmed temperature calcination, we obtained the mesopores TiO2 microsphere.The synthesized titania microspheres were made into normal phase chromatography packing, and performed well when testing their separation of alkaline substances. The bonded titania microspheres were made into reversed phase chromatography packing, which also showed a good resolution when separating alkaline substances.