| Titania has been drawing increasing attentions in recent years, owing not only to itsexcellent pH stability, but also to great mechanical strength,and amphoteric ion exchangercharacteristic. In this paper, titania materials were prepared through a ultrasonic waveassisted-sol-gel technique combine with surfactant synthesis route. The obtained titaniacolumn was used to analyse and determine aspartame and antioxidants in food, and theeffect of chromatographic condition on retention of synthetic food dyes was discussed,which exhibited the excellent property of chromatography separation.The research contents of this topic includes five parts:(1) Porous micrometer-level titania spheres for HPLC packing were prepared byultrasonic wave assisted sol-gel technique with titanium isopropoxide (Ti(OPri)4) astitanium source. The effects of some factors including ultrasonic wave,calcinationtemperature, and concentrations on the shape, gelation time, pore size, and specific surfacearea of the titania microspheres were determined. The obtained titania microspheres werecharacterized by BET and SEM measurements. The results show that the titaniamicrospheres were mostly regular-ball; the average particle size was6?m; the surface areawas87.79m2/g; the pore volume was0.1123mL/g and the average pore diameter was27.74nm.(2) Ultrasonic assisted sol-gel technique prepared titanium microspheres, andintroducted metal impurities inevitably in the process of synthesis that affected the physicaland chemical properties of titanium microspheres. In the experiment,the activation of theconcentration of HCl solution, the activation solution temperature, ultrasonic treatment ofthe experimental factors such as temperature and time were discussed. Through thedetermination of number of hydroxyl groups on the surface of titania spheres, and suredthe best activation conditions of titania spheres, as follows: titania spheres under theactivation temperature of90?and3mol/L HCl solution, ultrasonic treatment time was120min, the last treatingwas immersing18h, Ti-OH concentration on the surface can be6.7?moL/m2, exposed more active site,and easy to bonding reaction subsequent.(3) Carbon-18bonded titania stationary phases were prepared by modifying poroustitania particles with octadecyl dimethyl chlorosilane. Infrared spectroscopy (IR)analysis and Chemical stability of C18-TiO2packed column. The results showed that C18-TiO2filler has good chemical stability and chromatographic behavior with ReversedPhase (RP) characteristics. The reversed phase C18-TiO2packed column were evaluatedusing polycyclic aromatic system and the basic compound system. And it was proved thatthe alkaline substances can be separated effectively by C18-TiO2phase. So the separation ofbiological macromolecules and the alkaline substances can be explored on the foundation of this phase.(4)A method for the determination of acesulfame-k by HPLC on titania bondedstationary phase in drinkings was reported. The drinkings samples were analysted with aTitania Sachtopore-RP column (made by myself,150×4.6mm,6?m). The separationchromatographic conditions were: a mixture of methanol and water used as mobile phase,and the detection wavelength was214nm, with a flow rate of0.80mL/min, columntemperature was50?. The linear range was2.50~500?g/mL; The recoveries of themethod were between97.00%~101.00%, RSD?3.70%, with the detection limit of0.01?g/mL. The method is simple, accurate and precise and can be applied to the determinationof AK in drinkings.(5)A method for the determination of TBHQ, PG and BHT by HPLC on titania incooking oil and its relative products was reported in this paper. The chromatographicseparation conditions were: The samples of cooking oil and its relative products wereseparated with a Titania Sachtopore-RP column (250×4.6mm,5?m). a mixture ofmethanol and water with gradient elution containing1%phosphoric acid used as mobilephase, the detection wavelength was290nm, and with a flow rate of0.80mL/min. Thelinear range of TBHQ and PG was0.50~50?g/mL with the detection limit of0.20?g/mLand0.10?g/mL. The linear range of BHT was0.5-100?g/mL with a detection limit of2.0?g/mL. The recoveries of the method were between91.61%~114.11%. The method issimple, accurate and precise and can be applied to the determination of TBHQ, PG andBHT in cooking oil and its relative products. |
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