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31.
Aqueous two-phase extraction as an effective tool for isolation of geniposide from gardenia fruit 总被引:5,自引:0,他引:5
Natural products are normally obtained by organic solvent extraction and many subsequent chromatographic separations. Compounds of interest are often isolated with very low yield and limited purity. An aqueous two-phase extraction process combined with a simple ethanol treatment, for removing excess inorganic salt, has been developed for preparation of geniposide from gardenia. The system was comprised of PE62, a random copolymer composed of 20% ethylene oxide and 80% propylene oxide, KH2PO4 and ethanol. To find optimal conditions, the partition behavior of geniposide under an aqueous two-phase system was investigated. Various factors were considered, including the concentration of salt, the concentration of polymer, the sample loading, and the addition of ethanol. The experimental results demonstrated that increasing salt concentration or decreasing PE62 concentration results in enhancement of the geniposide partition in the salt-rich phase. The addition of ethanol and higher sample loading also promoted the partition efficiency of geniposide. Based on this study, an optimized system containing 5% PE62, 7.5% KH2PO4, and 10% ethanol was tested on a large-scale extraction. A 39.0-g aliquot of final product (in powder form) with 77% purity of geniposide can be effectively extracted from 500 g of gardenia fruit. This process is proved to be useful for industrial application of geniposide preparation. 相似文献
32.
In this study, porous glass fiber membranes were coated with monophenyl trimethoxysilane (MPh) and then sulphonated by chlorosulphonic acid to prepare the cation-exchange membranes with sulphonic acid groups. Different MPh-coating times were tested and the properties of the resulting membranes such as contact angle, FTIR spectrum, conductivity, and ion-exchange capacity were measured. It was found that the optimal MPh-coating time was 60 min and the related ion-exchange capacity was 49.5 μequiv./disc. The modified membrane under the optimal MPh-coating condition was adopted for lysozyme isolation. The results were compared with those for the commercial cation-exchange membrane with sulphonic acid groups (ICE 450 unsupported membrane). Although the prepared membrane exhibited less adsorption capacity than ICE 450 unsupported membrane in the batch lysozyme adsorption experiment, it showed lower non-specific binding ratio under higher salt concentration. In the flow process isolating lysozyme from hen egg albumen, the purification effectiveness obtained using the prepared cation-exchange membrane was superior to the ICE 450 unsupported membrane. 相似文献
33.
Huang HS Chiou JF Chiu HF Hwang JM Lin PY Tao CW Yeh PF Jeng WR 《Chemical & pharmaceutical bulletin》2002,50(11):1491-1494
The synthesis of a series of anthraquinone moieties bearing symmetrical sulfur-linked substituents in the 1 and 5 positions is described. These compounds were evaluated for their ability to inhibit the growth of suspended rat glioma C6 cells and human hepatoma G2 cells, respectively. In addition, the redox property of the compounds was determined based on the inhibition of lipid peroxidation in model membranes. Compounds 2a and 2h in this series compared favorably and exhibited the most potent cytotoxicity (0.02, 0.05 microM) against C6 cells in the XTT colorimetric assay. As far as redox properties are concerned, all bis-thio-anthraquinones show potential lipid peroxidation in model membranes very close to that of mitoxantrone (MX), and 2a, 2d, 2e, 2i, 2j, and 2k have more potential than that of MX. The lack of cytotoxicity of compound 2i cannot be related to lipid peroxidation, but the steric and electronic properties of the side-chain substituent maybe impair effective recognition of the cleavable complex. In contrast to MX, 2a and 2h are cytotoxic in rat glioma C6 cells and do not enhance lipid peroxidation in model membranes. 相似文献
34.
Electrogenerated chemiluminescence (ECL) of six new ethyne-based acridine derivatives (1-6) has been studied. The new acridine derivatives were synthesized by cross-coupling of 9-chloroacridine and corresponding donor-substituted phenylethynes under modified Sonogashira conditions. The donor groups were varied in the order of increasing steric hindrance and donor strength at the donor site. The solution phase photophysical properties and ECL of these compounds were studied comparatively in acetonitrile solvent. The UV-Visible spectra of compounds 1-5 exhibit closely the same maxima. Density functional theory (DFT) has been invoked to analyze and understand the unexpected UV-Visible absorption behavior. Compounds with weak electron donors produce excimer ECL irrespective of steric hindrance at the donor site, while the compound with a stronger donor gives rise to ECL that is blue-shifted with respect to its photoluminescence spectrum. All except one of these compounds also exhibit solid state fluorescence which may be useful for solid state devices such as organic light emitting diodes (OLEDs) and as laser dyes. The observed properties are discussed with reference to the structure of the compounds synthesized. 相似文献
35.
天祝煤MRF工艺热解焦油的组成分析 总被引:5,自引:0,他引:5
本文对天祝煤MRF(MutistageRotaryFurnace)热解焦油进行了常规及元素分析,了解其基本特性;用毛细管色谱分别对焦油各馏分进行了分析,共定性定量了103种化合物,酚类化合物以低级酚(苯酚、甲酚)为主,中性化合物为多烷基芳烃衍生物、脂肪族链状烷烃和烯烃。上述分析结果为从焦油中提取酚类化工原料或将其加工成各种燃料油的可行性提供了依据。 相似文献
36.
Yulu Yang Mingguang Wu Xingwang Zhu Hui Xu Si Ma Yongfeng Zhi Hong Xia Xiaoming Liu Jun Pan Jie-Yinn Tang Siang-Piao Chai Leonardo Palmisano Francesco Parrino Junli Liu Jianzhong Ma Ze-Lin Wang Ling Tan Yu-Fei Zhao Yu-Fei Song Pardeep Singh Pankaj Raizada Deli Jiang Di Li R. A. Geioushy Jizhen Ma Jintao Zhang Song Hu Rongjuan Feng Gang Liu Minghua Liu Zhenhua Li Mingfei Shao Neng Li Jiahe Peng Wee-Jun Ong Nikolay Kornienko Zhenyu Xing Xiujun Fan Jianmin Ma 《中国化学快报》1990,30(12):2065-2088
This roadmap demonstrates a series of two-dimensional nanomaterials, such as graphene, black phosphorus, oxides, layered double hydroxides, chalcogenides, bismuth-based layered compounds, MXenes, metal organic frameworks, covalent organic frameworks, and others, for environmental catalysis. 相似文献
37.
A trinuclear heterobimetallic Ru(II)/Pt(II) complex, cis-{Ru(phen)2[CN-Pt(DMSO)Cl2]2} (phen = 1,10-phenanthroline), is able to function as a "switch-on" luminescent chemodosimeter for sulfhydryl-containing amino acids and peptides via specific binding of the amino acids/peptides with the Pt(II) centers and the subsequent cleavage of the Ru(II)-Pt(II) cyano-bridge. 相似文献
38.
S. C. F. Au-Yeung S. Y. Fan J. C. Yu W. L. A. K. Chiu 《Fresenius' Journal of Analytical Chemistry》1998,361(2):210-213
A novel analytical approach is described that combines the preconcentration power of solvent extraction with the resolution
and sensitivity of a 500 MHz 1H NMR spectroscopic detection method for the quantitative determination of metals. Co(II), Cr(VI), Ni(II) and Pb(II) in water
are extracted into chloroform as dithiocarbamate complexes. By decoupling the protons and employing a solvent-induced shift
method, the 1H NMR spectrum containing the dithiocarbamate complexes of Co(II), Cr(VI), Ni(II) and Pb(II) is fully resolved at CDCl3/ C6D6 below 40%/60%. The detection limits for Co(II), Cr(VI), Ni(II) and Pb(II) are estimated to be 0.12, 0.073, 0.11 and 0.27
μg/mL, respectively, in the sample solution.
Received: 31 July 1997 / Revised: 24 October 1997 / Accepted: 31 October 1997 相似文献
39.
Five common food preservatives were analyzed by capillary electrochromatography, utilizing a methacrylate ester-based monolithic capillary as separation column. In order to optimize the separation of these preservatives, the effects of the pore size of the polymeric stationary phase, the pH and composition of the mobile phase on separation were examined. For all analytes, it was found that an increase in pore size caused a reduction in retention time. However, separation performances were greatly improved in monolithic columns with smaller pore sizes. The pH of the mobile phase had little influence on separation resolution, but a dramatic effect on the amount of sample that was needed to be electrokinetically injected into the monolithic column. In addition, the retention behaviors of these analytes were strongly influenced by the level of acetonitrile in the mobile phase. An optimal separation of the five preservatives was obtained within 7.0 min with a pH 3.0 mobile phase composed of phosphate buffer and acetonitrile 35:65 v/v. Finally, preservatives in real commercial products, including cold syrup, lotion, wine, and soy sauces, were successfully determined by the methacrylate ester-based polymeric monolithic column under this optimized condition. 相似文献
40.
Tam Nga Chiu Fletcher Stephen P. Vogels Christopher M. Westcott Stephen A. Decken Andreas 《Transition Metal Chemistry》2003,28(1):103-109
Dioxomolybdenum(VI) complexes derived from ethyl maltol (2-ethyl-3-hydroxy-4-pyrone) and 1-alkyl-2-ethyl-3-hydroxy-4-pyridin-4(1H)-ones have been prepared and characterized using physical methods including 1H- and 13C-n.m.r. spectroscopy, i.r., elemental analysis, and X-ray diffraction for the pyrone and 3-methylpyridine pyridinone derivatives. The octahedral complexes have the general formula cis-MoO2L2 where L = the deprotonated pyrone or pyridinone ligand. 相似文献