| Three dimensional structure and multi-ended groups afford hyperbranched polymers (including dendrimer) advantage functionalities in many fields, and have attracted more and more attention recently.In full use of the advantages of the three-dimentional structure and chemcial agility, dendrimer and hyperbranched macromolecules with C8group, phenyl group, and cyclodextrin group are synthesized and used as stationary phases and microextraction coating by different forms in accordance with specific applicationsIn high performance liquid chromatography, phenyl-allyl-ended carbosilane dendrimer is hydrosilylated with MeHSiCl2and is bonded to5μm silica gel. The affoded surface modified silica gel is characterized by IR, element analysis and hydrophobicity test. Column evaluation by peak sequence of toluene and2-choloride-nitro-benzene indicates that a multi-functional interaction modle plays an important role in separation process-they are predicted as end group-analyte interaction, branch-analyte interaction and capsulation interaction.Monolithic materials are recent interest especially in liquid chromatography field. Polyethylene glycol(PEG) is used as phase modulator in acid-catalyzed tetraethoxysilane/water(TEOS) system. Continuous structure with different morphology,"r" value, which represents the number ratio of PEG monomer unit to tetrethoxysilane, together with temperature, have important role in formation of this bi-continuous morphology. C8-ended hyperbranched carbosliane is synthesized and characterized by IR and1HNMR, and is bonded with hydrolyzable ethoxyl group by hydrosilylation with triethoxysilane. Co-hydrolyzed with tetraethoxysilane in optimized condition, bi-continuous structure with hyperbranched carbosilane is obtained.Benzyl terminated carbosilane hyperbranched polymer is synthesized and characterized by IR,1H NMR,13C NMR. It is hydrosilylated with triethoxysilane and hydrolyzed with tetraethoxysilane with inorganic acid/organic acid as catalyst specifically. Obtained morphologies are carefully studied. Great number of cracks occurred in gel body in sol-gel process with catalysis by inorganic acid. This has negative effects to chromatography process. The column coated with hydrolyzable phenyl-ended hyperbranched carbosilane with trifluoroacetic acid catalysis by sol-gel process gives excellent performance in separatioin of homologues. Experiment analysis reveals that the column has ability to detect1ppm trace amount analytes.Based on the work above, benzyl-terminated hyperbranched carbosilane is further used as fused silica inner wall coating and finds its application in microextraction field. A contrasting column coated with phenylmethyldiethoxylsilane is prepard in the same conditions as that of hyperbranched polymer coating. Experiments reveals that hyperbranched structure coating have much larger absorption amount than phenylmethyldiethoxylsilane coating (by ten fold) and reaches absorption balance point in much shorter time(20mins). Trace analysis by this coating reveals excellent property. An experiment is designed to test the comprehensive performance of the home-made hyperbranched carbosilane bearing SPME/Capillary Gas Chromatography combination model vs a commercial SPME/capillary model. Testing results show that the combined function of hyperbranched column/hyperbranched microextraction coating possess prominent property than commercial model. Sharp peaks at the challenge of trace analysis of1ppm benzyl/water sample are obtained.β-Cyclodextrin react with allyl-ended hyperbranched carbosilane and the product is characterized by IR. Fused silica capillary is filled with β-cyclodextrin-hyperbranched carbosilane and the resulted chromatography property is tested. Homologues, isomers and especially enantiomers get base-line separated. The unique three-dimention structure of hyperbranched carbosilane combines well with the guest-inclusion function of β cyclodextrin and give perfect behavior as stationary phase in chromatography. |
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