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葡萄酒中白藜芦醇的固相萃取GC/MS法测定及其生理活性的初步研究 总被引:12,自引:0,他引:12
用反向C18固相萃取小柱对葡萄酒进行了预处理,然后用BSTFA硅烷化试剂对萃取物进行了衍生化处理,用气相色谱/质谱对葡萄酒中顺式、反式白藜芦醇进行了同时测定,建立了定量分析方法.对方法的精密度和回收率进行了测定,方法的相对标准偏差分别为4.48%(顺式)和5.23%(反式).顺式、反式白藜芦醇的平均回收率分别为94.4%和97.6%.并对10种国产葡萄酒和两种进口葡萄酒样品进行了测定.对白藜芦醇的生理活性也进行了实验,初步探讨了白藜芦醇对大鼠血管平滑肌细胞(VSMC)、大肠癌细胞株Lovo细胞和小鼠成纤维株3T3细胞的生长生殖活性的影响,观察了其形态变化. 相似文献
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本文首先从免疫传感器的构建开始论述,对近5年有关免疫传感器用于环境污染物检测的文章进行了分类和归纳,对其中的三大热点进行了详细介绍,即全内反射荧光、光波导模式谱和表面等离子共振免疫传感器.其次对该领域的研究现状进行了分析,重点从信号放大技术、多组分检测、传感器的再生以及自动化和小型化等方面进行评述.最后,对免疫传感器用于环境污染物检测的发展趋势作了讨论. 相似文献
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综述了近年来环状芳香低聚物的合成及应用研究发展状况,对其合成方法和应用情况进行了综述和分析,并对今后的研究发展进行了预测。 相似文献
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医学成像光谱技术研究进展 总被引:2,自引:1,他引:1
李庆利 《影像科学与光化学》2008,26(6):507-515
从成像光谱技术的发展概况出发,综述了医学成像光谱技术的研究现状和最新进展,对现有的医学成像光谱仪按照类别进行分析,对其在生物医学领域应用概况和应用前景进行了探讨.对医学成像光谱技术的发展趋势和今后研究需要解决的问题进行了评述. 相似文献
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应用系统聚类法对海洛因裂解谱图分类 总被引:1,自引:0,他引:1
采用系统聚类法对海洛因样品裂解谱图进行分类研究.为了能够对铂丝裂解法分析海洛因溶液的可行性进行正确评价,首先对系统聚类法中的相似性量度和聚类方法进行了选择,然后运用相关性分析法和系统聚类法对裂解谱图的重现性结果进行测定,得到了较好的评价结果;最后对10种海洛因样品的裂解谱图进行了系统聚类分析,得出了分类结果. 相似文献
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鉴于一氧化碳(CO)氧化在基础研究、 环境保护和实际应用中的重要性, 人们对其进行了广泛的研究. 金属有机骨架(MOFs)由于具有永久孔隙, 结构多样且可调控, 是一种很有前途的CO氧化催化剂. 本文对近年来MOFs和MOF基催化剂用于CO氧化的研究进展进行了系统的总结, 并根据催化剂活性物种/位点进行了简要的分类介绍. 除了催化剂的化学结构, 催化剂的负载量、 制备方法和预处理技术以及反应温度等对催化性能的影响也在文中进行了讨论. 最后, 本综述对该研究领域进行了总结和展望. 相似文献
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Pt/HM、Pd/HM催化剂上CO氧化反应活性和动力学研究 总被引:1,自引:0,他引:1
研究了Pt/HM、Pd/HM催化剂上CO氧化反应的活性,求出了各种催化剂的CO氧化反应动力学方程。考察了不同气氛下CO氧化活性的演变规律和V4+、Co2+离子对Pt、Pd的助催化作用,并用催化剂集团结构适应模型对以上结果作出了解释。 相似文献
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ClO与ClO自由基反应机理及电子密度拓扑分析 总被引:1,自引:0,他引:1
利用密度泛函理论对ClO与ClO自由基反应机理进行了深入理论探讨,在B3LYP/6-311++G(3df)水平上对该反应体系的反应物、中间体、过渡态及产物进行了几何构型优化,对反应通道进行了IRC(内禀反应坐标)路径解析,计算了沿各反应通道的能垒和离解能,并进行了零点能校正.从量子拓扑学的角度,对反应通道IRC途径上一些重要点进行了电子密度拓扑分析,讨论了反应过程中化学键的断裂、生成以及键的变化规律,找到了反应途径的能量过渡态和结构过渡态. 相似文献
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The surface disproportionation reaction mechanism of aluminum subchloride on the aluminum (100) surfaces has been investigated by the plane-wave density functional theory (DFT).Three kinds of possible reaction mechanism of AlCl disproportionation reaction on the aluminum (100)surfaces have been taken into account. The structures of reactants and products have been optimized, transition states have been confirmed and activation energies have been calculated. The adsorption energy of reactants and desorption energy of products have been determined. All of these have been employed to confirm the reaction mechanism and the rate determining step of AlCl disproportionation reaction on the aluminum (100) surfaces. 相似文献
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Suchhanda S. Swain Lakshmi Unnikrishnan Smita Mohanty Sanjay K. Nayak 《Surface and interface analysis : SIA》2023,55(1):10-25
Carbonaceous nanomaterials and their derivatives have been inspired tremendous enthusiasm in the scientific community. They have been excogitated as the encouraging attributes and the qualified dispersed phase to develop multi-functional composites. Particularly, graphene and carbon nanotube (anisotropic fillers) have gained substantial research interest owing to their promising characteristics. This highlights an innovative technique to synthesize hybridized nanotube and nanosheet. Initially, parent materials have been synthesized: The pristine CNT has been modified by acid mixture solution, and reduced graphene oxide has been prepared by chemical reduction method. Henceforth, the self-assembly in situ sol–gel technique has been endorsed here. The synthesized nanohybrids have been characterized by different spectroscopic techniques: FTIR, Raman, UV, and XPS to confirm the attachment of multifunctionalities; meanwhile, the composition and stability have been investigated from XRD and TGA plots. The magnitude of surface charge and particle size distribution have been evaluated for the parent and hybridized products; further, morphology of all the samples has been authenticated from FESEM and TEM. 相似文献
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The properties, apparatus and applications of overpressured thin-layer chromatography (OPTLC) have been reviewed. In the Introduction planar chromatography has been briefly characterized, with particular attention to TLC. The general properties of OPTLC and methods of development of chromatograms in this technique have been then given. The construction of chambers and equipment for OPTLC has been described, paying attention to two-dimensional columns. The properties of chambers for OPTLC have been characterized considering the flow of eluent, sorbent-eluent interactions and the efficiency of various systems. OPTLC, TLC and HPTLC have been compared and also a comparison between OPTLC with a constant (linear) eluent flow-rate and with a decreasing eluent flow-rate has been made. Analytical applications of OPTLC have been described and examples of separations of mixtures have been given. 相似文献
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Organic monolithic stationary phases have been synthesized in UV-transparent fused-silica capillaries, which have been used as test format of microfabricated device channels. The columns have been prepared by in situ polymerization of butyl acrylate, lauryl acrylate, 1,3-butanediol diacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in a ternary porogenic solvent. The resulting stationary phases have been tested in capillary electrochromatography and exhibited reversed-phase chromatography behavior toward neutral solutes. Van Deemter plots of phenylureas and polycyclic aromatic hydrocarbons, selected as model analytes, have been determined to study the influence of various polymerization and separation parameters on properties of the monoliths. The amount of AMPS and the nature of monomers in the polymerization solution have been thus adjusted. It has been observed that the ionic strength of the mobile phase may affect significantly the efficiency of the separation. The effect of the percentage of acetonitrile in the mobile phase on efficiency and permeability of the organic monoliths has also been investigated. Efficiencies greater than 300,000 plates/m have been obtained with the test compounds. Stability and reproducibility have been extensively studied. 相似文献
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The phase behavior of Eucalyptus oil/ Tween 20/ Butanol/ Water and Eucalyptus oil/ Tween 20/ Cinnamic Alcohol/ Water systems have ben studied in detail. Both triangular and tetrahedral representations have been considered to understand the topological nature of the multicomponent mixtures. Shear viscosities of typical multiphasic compositions have been measured at different rates and temperatures. The samples have undergone shear thinning. The effect of temperature on the volumes of multiphasic compositions have been also investigated both increase and decrease of the extents of different phases have been witnessed. The enthalpy of dissolution of both water and oil in presence of amphiphile solutions in oil and water respectively have been determined calorimetrically. Considering the phase separation point to be the point of maximum solubility of microdroplets, the free energies and hence entropies ofsolution have been estimated. The above phy.sicochemical features have been also examined in presence of additives, viz, NaGI and urea. 相似文献
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Tatsuhiko Nakano Víctor E. Mrquez María T. Di Parsia Cecilia Surez 《Journal of mass spectrometry : JMS》1978,13(4):236-242
The mass spectra of some substituted oxadiazoles have been determined and analysed with the aid of high resolution mass spectrometry. Some characteristic and major differences between their spectra have been noted, and possible rationalizations have been advanced. The main fragmentation patterns of the 1,3,4-oxadiazole derivatives have been interpreted in terms of diazirine intermediates. Specific skeletal rearrangement processes have been observed in the spectra of the 1,3,4- and 1,2,4-oxadiazoles, and possible mechanisms are proposed. 相似文献
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《International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry》1986,27(2):111-121
The structure and the reactions of primary oxidation and reduction products in irradiated organic crystals and solid polymers have been investigated. The data from pulse radiolysis with nanosecond time resolution have been combined in a new manner with the data obtained by low-temperature irradiation and ESR spectroscopy. By this combination optical spectra have been assigned, reaction mechanisms have been studied and ESR components have been identified using the kinetic data from pulse radiolysis. The method has been particularly useful in the study of negative-ion radicals in carboxylic acid derivatives, of trapped electrons in polyhydroxy compounds, and of ionic species in polymers. 相似文献