Preparation Of Metal Oxide Coated Silica Core-shell Microspheres And Application For Highly Specifc Phospholipids Enrichment

Phospholipids （PLs） are very important structural material of cell membrane,which plays a key role in cell signal transmission, cell proliferation and apoptosis.Analysis of phospholipids and non-phospholipid lipid molecules is very important fordisease diagnosis. However, the phospholipids-based matrix effect in massspectrometry （MS） may significantly affect the efficiency and reproducibility of theionization process of other small molecules. At the same time， low-abundancephospholipids are difficult to observe in MS analysis. In this study, the newZirconia-coated silica （ZrO₂/SiO₂） and titania-coated silica （TiO₂/SiO₂） core-shellcomposite microspheres, which have a two-dimensional structure and high specificsurface area, had been synthesized, and a new strategy for selective enrichment ofphospholipids from biological samples using these two kinds of core-shell assolid-phase extraction materials prior to analysis by RPLC-ELS and HPLC–ESI-MSwas developed. By using this method, the increase in the detector’s response of thelow-abundance phospholipids would be found, and the effect on the analysis ofnon-phospholipid lipid molecules without interference of phospholipids in serumwould be studied.1.The Zirconia-coated silica（ZrO₂/SiO₂）were prepared by NH3-H2Ovapor-induced internal hydrolysis. Zirconia-coated silica micro sphereswere werecharacterized by X-ray diffractiton, scanning electronmicroscopy （SEM）, UV-visiblediffuse reflectance UV-vis DRS) and N2adsorption-desorption experiments（BET）.The results showed the zirconia-coated silica microspheres has relatively a largerspecific surface area. Zirconia layer coated on the silica was amorphous,and highlydispersed on the the surface of the silica. The mechanism of the formation of thereaction was speculated.2. The method of C8-HPLC-ELSD of annalysis of the phospholipid standardswas established. The absorption ability of ZrO₂/SiO₂microspheres packed into the solid-phase extraction （SPE） towards phospholipids was investiged. The resultsshowed ZrO₂/SiO₂SPE had a much higher selectivity and high recoveries than hat ofbulk ZrO₂.4.The titania-coated silica （TiO₂/SiO₂） was prepared by water vapor hydrolysisand charcaterized by canning electron microscopy （SEM） X ray diffractio n （XRD）,UV-Vis diffuse reflectance （UV-vis DRS）. Results showed titania was successfullycoated on the surface of silica, and which was amorphous,5. ZrO₂/SiO₂and TiO₂/SiO₂were used for the pretreatment materials forselctively phospholipids enrichment prior to analysis with UPLC-Q-TOF. Byelimination of phospholipids-based matrix effect in mass spectrometry （MS）, reponsesof some non-phospholipid lipid molecules in serum were increased. And morelow-abundance phospholipids would be found and identifed.6. The ZrO₂/SiO₂SPE technology,was used in the investigation of metabonomicsof pancreatic cancer With the aid of the recent advent of the profiling method oflipidomics and classification analysis of lipid molecules in our lab, more metabolitesand information about endogenous phospholipids of pancreatic cancer had beengained to help finding the common and specific biomarkers among the diseases.