Preparation Of Bonded Titania Monolithic Stationary Phase And Its Application Research

The chemical stability and good mechanical strength of titania make it into a newdirection for research in the field of stationary phase HPLC. With the recent studies ontitania are more deeply, the application of titanium dioxide stationary phase is graduallyincreasing. There are already packed titania column with goods, but due to the complexityof the packed column itself makes the preparation process to reduce repetitive filled pillarsand columns life is relatively low, so it can not achieve the desired state. Because of themonolithic column has properties of efficient, fast, stable performance, high throughput andhigh mechanical strength,so it has an incomparable advantage of packed columns. Thereare already bonded silica monolithic column came to the market, while the overall study oftitanium column is still in the experimental stage, there is none reports about bonded titaniamonolithic column (there refers to the beginning of the titanium matrix composed entirely,not including titanium rubber coated silica matrix). In this paper, Carbon-18bonded titaniamonolithic column were prepared by modifying titania monolithic column withchlorodimethyloctadecylsilane. Moreover, it can be used to the quantitative analysis ofbenzoic acid.The four aspects are included in this paper as follows:(1) Carbon-18bonded titania monolithic column were prepared by modifying titaniamonolithic column with chlorodimethyloctadecylsilane. The titania monolithic column wasprepared by a sol-gel synthesis route, via using titanium isopropoxide, glacial acetic acid,hydrochloric acid, PEO and water which has a higher surface area. Effect factors onactivation and bonding process were studied. The characterization of bonding products wasused acid-base titration, weight loss rate measurement, Fourier transform infraredspectroscopy, field trips for hydrophobic. And applied it to high performance liquidchromatography (HPLC) analyses separation of acidic compounds and alkaline compoundsrespectively, the result was satisfied.(2) The compound of benzoic acid was analyzed with synthesized Carbon-18bondedtitania monolithic column, in order to fully understand the retention mechanism of benzoicacid on bonded titania column, methanol percentage, buffer pH, buffer concentration flowrate of the mobile phase were investigated. And applied it to soft drinks for quantitativeanalysis.(3) This part aims at establishing a rapid method for simultaneous separation anddetermination of the sweeteners including cyclamate, acesulfame, and aspartame inbeverages by titania-based RP-HPLC. The chromatographic conditions were as follows: atitania Sachtopore-RP C18column (250mm×4.6mm;5μm) as a separation column, a mixture of water and methanol at a volume ratio of95to5containing1.0%phosphate acidused as mobile phase, flow rate of1.0mL min-1, and the detection wavelength was205nm.The linear ranges of cyclamate and aspartame were0.02~8.0mg mL-1with limits ofdetection (LODs) of16.35μg mL-1and19.56μg mL-1, respectively, and their limits ofquantitation (LOQs) were55.50μg mL-1and68.50μg mL-1, respectively. The recoveries ofcyclamate were between93.52%and103.54%. The recoveries of aspartame were between93.31%and102.63%. The linear range of acesulfame was0.125~50μg mL-1with a LODof0.08μg mL-1and a LOQ of0.25μg mL-1. The recoveries of acesulfame were between94.34%and103.21%. Relative standard deviation (RSD, n=8) for all determinations wasless than0.72%.(4) This part aims at establishing a rapid method for simultaneous separation anddetermination of the acetic acid and succinic acid by titania-based RP-HPLC. Thechromatographic conditions were as follows: a titania Sachtopore-RP C18column (250mm×4.6mm;5μm) as a separation column, a mixture of water and methanol at a volumeratio of98to2containing5mmol/L phosphate pH1.5used as mobile phase, flow rate of0.7mL min-1, column temperature60℃, and the detection wavelength was215nm. Thelinear range of acetic acid was0.05~1.0mg mL-1with limits of detection (LOD) of3.40μgmL-1, and the limits of quantitation (LOQ) was11.50μg mL-1. The recoveries of acetic acidwas between92.13%and101.21%. Relative standard deviation (RSD, n=8) was0.92%.The linear range of succinic acid was0.025~0.75mg mL-1with a LOD of1.76μg mL-1anda LOQ of6.00μg mL-1. The recoveries of succinic acid was between93.25%and99.81%.Relative standard deviation (RSD, n=8) was0.78%.