Preparation And Characterization Of Zirconia Microsphere As Stationary Phase For HPLC

Mono-disperse and micron of porous zirconia spheres were synthesized by the improved process of polymerization-induced colloid aggregation (PICA). In this process, ZrOCl2?8H2O was used as raw material with formaldehyde and urea as solidified agents,acetyl acetone was used as stabilizing agent. Porous zirconia particles obtained after vacuum drying and sintering at 700oC which had a narrow particle size distribution and appropriate aperture,pore structure. Phase compositions were mainly tetragonal and monoclinic.Porous zirconia microspheres were also strong enough to withstand the packing of a HPLC column.The optimum process parameters were determined through our experiments. The result showed that pH,the temperature and time of starting sol,sintered temperature affected the particle size; We also gained optimum condition: the polymer precursor to zirconia ratio: 1.33(mol/mol); the urea to formaldehyde ratio: 0.8(mol/mol);the pH of sol:1.5; the temperature and time of starting sol:90oC and 12h;the yellow hydrogels were separately preheated treatment at 120 oC,170 oC about 12h at vacuum drying chamber in order to evaporate moisture content and partial organic matter,then the zirconia of preheated treatment were sintered at electric muffle furnace from room-temperature to 700 oC and kept this temperature about 9h in order to improve their mechanical strength.The establishment and heat treatment process to resin spheres were characterized by FT-IR and TG-DTA; the pattern and size distribution to resin spheres and micro-spheres were observed by TEM and SEM, The final diameter of the zirconia spheres were 2.6μm; phase compositions were mainly tetragonal and monoclinic by XRD; specific surface area was 32 m2/g by BET, the average aperture belonged to meso-pore range; The mechanical strength was at least 45 MPa by column packing technique.Zirconia spheres loading material were put into unified standards chromatographic column (450mm×4.6mm) by wet packing method, then alkaline system and neutral,basic,acid system were separated and purified under the appropriate detection condition. The satisfied separation result was achieved. The home-made zirconia spheres and the silicon oxide spheres supplied in the market were separately loaded into chromatographic column as stationary phase. The same alkaline system was separated under the corresponding detection condition. The experimental results showed that home-made zirconia spheres were feasible to separate alkaline compound by the chromatographic column. The retaining time was shorter than that of silica and the peak shape was also symmetry. So it could be concluded that the surface of zirconia spheres had obviously alkaline characteristic which silica spheres could not match with them.