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盾叶薯蓣中薯蓣皂甙元的反相高效液相色谱测定 总被引:14,自引:1,他引:13
盾叶薯蓣(Dioscorea Zingiberensis)为薯蓣科植物,其根茎俗称黄姜,产于四川、陕西、云南、湖南、湖北等省。本品为不常用中药,用于工业上提取皂素,主要成分是皂甙,水解得薯蓣皂甙元。它是异螺旋甾烷衍生物,化学名为Δ~5-异螺旋甾烯-3β-醇,是生产甾体激素类药物原料。以往测定薯蓣科植物中薯蓣皂甙元的含量多采用重量法、库伦法、薄层扫描等方法。这些定量方法操作繁杂,测定准确度不高。气相色谱测定皂甙元曾有文献报道。本文研究了薯蓣皂甙元的反相高效液相色谱测定,基于样品中各组分 相似文献
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重楼中薯蓣皂甙元的反相高效液相色谱测定 总被引:14,自引:0,他引:14
采用高效液相色谱法测定了重楼中薯蓣皂甙元的质量分数。样品先经甲醇提取,再经酸水解,将重楼甾体皂甙转变成薯蓣皂甙元,以SymmetryC8柱为色谱柱,以V(乙腈)∶V(水)=75∶25溶液为流动相,检测波长203nm,重复性较好,结果令人满意。 相似文献
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提出了高效液相色谱法测定怀山药中薯蓣皂苷元的含量。样品经无水乙醇提取,用ZORBAX SB-C18色谱柱分离,以甲醇-水(80+20)溶液为流动相淋洗,在波长210 nm处进行测定。薯蓣皂苷元的质量在10~150 ng范围内与其峰面积呈线性关系,检出限(3S/N)为2.5 ng。方法用于分析怀山药样品,回收率在94.2%~104%之间,测定值的相对标准偏差(n=6)为3.1%。 相似文献
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利用超临界CO2萃取技术从穿山龙中提取薯蓣皂甙元,建立了反相高效液相色谱法测定穿山龙中薯蓣皂甙元的方法.采用Shim-pack CLC-ODS(150 mm×4.6 mm,5 μm)色谱柱,流动相为V(甲醇):V(水)=99:1,流速为1.0mL/min,UV检测波长为206 nm.在0.2~2.0 mg/mL范围内,薯蓣皂甙元峰面积与其质量浓度呈良好的线性关系,r=0.9997.进行了高、中、低3个不同浓度的加标回收率测定,相应的回收率分别为101.5%,99.88%,98.45%,平均值99.94%,RSD为1.7%. 相似文献
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中药物质基础的高效液相色谱分离分析方法研究 总被引:2,自引:0,他引:2
高效液相色谱方法已成为中药物质基础研究的重要手段.在中药质量控制、中药标准品制备、活性化合物发现等方面发挥着不可替代的作用.然而我们的实验数据表明,一个中药材可能包含上万个化合物.中药物质基础的复杂性对高效液相色谱方法提出了巨大挑战.本文针对液相色谱方法在中药物质基础分离分析中存在的问题与难点,结合红花、黄连、姜黄三味药材样品,从亲水色谱分离模式、新型色谱固定相、二维液相色谱分离系统和液相色谱质谱联用技术等方面讨论了液相色谱的分离分析方法和发展方向.结果表明,高效液相色谱新技术新方法在中药复杂体系的分离分析中具有很大的发展潜力和应用前景. 相似文献
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考察了烷基酚聚氧乙烯醚在反相色谱、正相键合色谱、硅胶吸附色谱、体积排阻色谱4种不同液相色谱分离模式中的分离效果,分别采用Kromasil C_(18)(250 mm× 4.6 mm,5 μm)、Agilent ZORBAX NH2(250 mm× 4.6 mm,5 μm)、Waters Spherisorb S3W(150 mm×2.0 mm,3 μm)和Shodex MSpak GF-310 2D(150 mm×2.0 mm,5 μm)色谱柱,以225 nm为紫外检测波长,对不同液相色谱分离模式的流动相组成、梯度洗脱条件、柱温、流速等进行了优化,并对烷基酚聚氧乙烯醚在不同液相色谱分离模式中的保留机理进行了初步探讨.结果表明,正相键合色谱实现了烷基酚聚氧乙烯醚的最佳分离;硅胶吸附色谱和体积排阻色谱的分离效果较正相键合色谱稍差. 相似文献
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色谱柱是色谱分离分析的“心脏”,液相色谱技术的每一次重大进展都与分离固定相的突破密切相关。如上世纪70年代末期高效液相色谱技术的建立和90年代初期“灌流色谱”(Perfusion Chromatography)的发展都是基于多孔硅胶和“穿透孔”分离固定相的发展。近年来,基于特殊孔结构的1.5~2.0μm高强度复合材料的制备成功地催生了超高效液相色谱(UPLC)分离技术,而整体柱材料作为新一代的分离介质,已成为色谱领域广泛研究的前沿课题之一,并已经在样品预处理、手性分离、生物分离分析等领域获得十分广泛的应用。我国色谱研究工作者在多孔硅胶固定相、手性分离固定相、亲和色谱固定相和整体柱固定相等研究领域都取得了重大的进展,有些方面的研究工作已达到或领先于国际先进水平。 相似文献
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梯度加压毛细管电色谱同时分离大黄提取液中5种蒽醌类化合物 总被引:7,自引:0,他引:7
建立了同时分离药用大黄提取液中大黄酸、芦荟大黄素、大黄素、大黄酚和大黄素甲醚5种蒽醌类活性成分的梯度加压毛细管电色谱的新方法.实验结果显示,大黄提取液中的5种蒽醌化合物可在22min内完全分离,梯度洗脱微柱液相色谱的柱效为等度洗脱微柱液相色谱的6.63倍,梯度毛细管电色谱的柱效为梯度微柱液相色谱的4.6倍. 相似文献
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Mordvintsev DY Polyak YL Levtsova OV Tourleigh YV Kasheverov IE Shaitan KV Utkin YN Tsetlin VI 《Computational Biology and Chemistry》2005,29(6):398-411
Short-chain alpha-neurotoxins from snakes are highly selective antagonists of the muscle-type nicotinic acetylcholine receptors (nAChR). Although their spatial structures are known and abundant information on topology of binding to nAChR is obtained by labeling and mutagenesis studies, the accurate structure of the complex is not yet known. Here, we present a model for a short alpha-neurotoxin, neurotoxin II from Naja oxiana (NTII), bound to Torpedo californica nAChR. It was built by comparative modeling, docking and molecular dynamics using 1H NMR structure of NTII, cross-linking and mutagenesis data, cryoelectron microscopy structure of Torpedo marmorata nAChR [Unwin, N., 2005. Refined structure of the nicotinic acetylcholine receptor at 4A resolution. J. Mol. Biol. 346, 967-989] and X-ray structures of acetylcholine-binding protein (AChBP) with agonists [Celie, P.H., van Rossum-Fikkert, S.E., van Dijk, W.J., Brejc, K., Smit, A.B., Sixma, T.K., 2004. Nicotine and carbamylcholine binding to nicotinic acetylcholine receptors as studied in AChBP crystal structures. Neuron 41 (6), 907-914] and antagonists: alpha-cobratoxin, a long-chain alpha-neurotoxin [Bourne, Y., Talley, T.T., Hansen, S.B., Taylor, P., Marchot, P., 2005. Crystal structure of Cbtx-AChBP complex reveals essential interactions between snake alpha-neurotoxins and nicotinic receptors. EMBO J. 24 (8), 1512-1522] and alpha-conotoxin [Celie, P.H., Kasheverov, I.E., Mordvintsev, D.Y., Hogg, R.C., van Nierop, P., van Elk, R., van Rossum-Fikkert, S.E., Zhmak, M.N., Bertrand, D., Tsetlin, V., Sixma, T.K., Smit, A.B., 2005. Crystal structure of nicotinic acetylcholine receptor homolog AChBP in complex with an alpha-conotoxin PnIA variant. Nat. Struct. Mol. Biol. 12 (7), 582-588]. In complex with the receptor, NTII was located at about 30 A from the membrane surface, the tip of its loop II plunges into the ligand-binding pocket between the alpha/gamma or alpha/delta nAChR subunits, while the loops I and III contact nAChR by their tips only in a 'surface-touch' manner. The toxin structure undergoes some changes during the final complex formation (for 1.45 rmsd in 15-25 ps according to AMBER'99 molecular dynamics simulation), which correlates with NMR data. The data on the mobility and accessibility of spin- and fluorescence labels in free and bound NTII were used in MD simulations. The binding process is dependent on spontaneous outward movement of the C-loop earlier found in the AChBP complexes with alpha-cobratoxin and alpha-conotoxin. Among common features in binding of short- and long alpha-neurotoxins is the rearrangement of aromatic residues in the binding pocket not observed for alpha-conotoxin binding. Being in general very similar, the binding modes of short- and long alpha-neurotoxins differ in the ways of loop II entry into nAChR. 相似文献
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Blood cells naturally auto-segregate in postcapillary venules, with the erythrocytes (red blood cells, RBCs) aggregating near the axis of flow and the nucleated cells (NCs)--which include leukocytes, progenitor cells and, in cancer patients, circulating tumor cells--marginating toward the vessel wall. We have used this principle to design a microfluidic device that extracts nucleated cells (NCs) from whole blood. Fabricated using polydimethylsiloxane (PDMS) soft lithography, the biomimetic cell extraction device consists of rectangular microchannels that are 20-400 μm wide, 11 μm deep and up to 2 cm long. The key design feature is the use of repeated expansions/contractions of triangular geometry mimicking postcapillary venules, which enhance margination and optimize the extraction. The device operates on unprocessed whole blood and is able to extract 94 ± 4.5% of NCs with 45.75 ± 2.5-fold enrichment in concentration at a rate of 5 nl s(-1). The device eliminates the need to preprocess blood via centrifugation or RBC lysis, and is ready to be implemented as the initial stage of lab-on-a-chip devices that require enriched nucleated cells. The potential downstream applications are numerous, encompassing all preclinical and clinical assays that operate on enriched NC populations and include on-chip flow cytometry (A. Y. Fu et al., Anal. Chem., 2002, 74, 2451-2457; A. Y. Fu et al., Nat. Biotechnol., 1999, 17, 1109-1111), genetic analyses (M. M. Wang et al., Nat. Biotechnol., 2005, 23, 83-87; L. C. Waters et al., Anal. Chem., 1998, 70, 5172-5176) and circulating tumor cell extraction (S. Nagrath et al., Nature, 2007, 450, 1235-1241; S. L. Stott et al., Proc. Natl. Acad. Sci. U. S. A., 2010, 18392-18397; H. K. Lin et al., Clin. Cancer Res., 2010, 16, 5011-5018). 相似文献
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Several newly studied species of the Scrophulariaceae, Lamiaceae, and Ranunculaceae spread in Bulgaria have been analyzed for their surface flavonoid profiles. Except Pulsatilla montana (Hope) Rchb. (Ranunculaceae) all taxa now studied accumulated mainly apigenin, luteolin, and it's derivatives. This is the first report for the presence on external flavonoid aglycones in genus Pulsatilla. Quercetin-3'-methyl ether is a new citation for P. montana. The presence on surface flavonoid aglycones in species Veronica bellidioides L., V. persica Poir., Odontites verna (Bell.) Dum., Laminiastrum galeobdolon Heist ex Fabr., Glechoma herbaceae L., Ajuga genevensis L., and A. reptans L. are reported for the first time too. 相似文献
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Ramkrishna Adhikary Holger Schönenbrücher Mark A. Rasmussen Thomas A. Casey Amir N. Hamir Marcus E. Kehrli Jürgen A. Richt Jacob W. Petrich 《Photochemistry and photobiology》2009,85(6):1322-1326
We describe a comparison of the fluorescence spectra of bovine tissues with murine tissues in order to determine whether spectral features are conserved and whether an appropriate and practical laboratory small animal model system could be identified to be used for investigation of tissue- and age-related fluorescence signal patterns. Recently it has been shown that spectral signatures of lipofuscin have enabled the detection of bovine central nervous system (CNS) tissue in meat products with high sensitivity (Schönenbrücher, H., Adhikary, R., Mukherjee, P., Casey, T.A., Rasmussen, M.A., Maistrovich, F.D., Hamir, A.N., Kehrli, M.J., Richt, J., Petrich, J.W. [2008] J Agric Food Chem 56 , 6220–6226). We report that brain and spinal cord of mice provide fluorescence spectra similar to those of bovine brain and spinal cord. It is concluded that murine CNS tissue is an appropriate model system for bovine CNS tissue for the development of fluorometric CNS detection assays. 相似文献
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Many microarray experiments involve examining the time elapsed prior to the occurrence of a specific event. One purpose of these studies is to relate the gene expressions to the survival times. The Cox proportional hazards model has been the major tool for analyzing such data. The transformation model provides a viable alternative to the classical Cox's model. We investigate the use of transformation models in microarray survival data in this paper. The transformation model, which can be viewed as a generalization of proportional hazards model and the proportional odds model, is more robust than the proportional hazards model, because it is not susceptible to erroneous results for cases when the assumption of proportional hazards is violated. We analyze a gene expression dataset from Beer et al. [Beer, D.G., Kardia, S.L., Huang, C.C., Giordano, T.J., Levin, A.M., Misek, D.E., Lin, L., Chen, G., Gharib, T.G., Thomas, D.G., Lizyness, M.L., Kuick, R., Hayasaka, S., Taylor, J.M., Iannettoni, M.D., Orringer, M.B., Hanash, S., 2002. Gene-expression profiles predict survival of patients with lung adenocarcinoma. Nat. Med. 8 (8), 816-824] and show that the transformation model provides higher prediction precision than the proportional hazards model. 相似文献
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Reconstruction of phylogenetic trees for very large datasets is a known example of a computationally hard problem. In this paper, we present a parallel computing model for the widely used Multiple Instruction Multiple Data (MIMD) architecture. Following the idea of divide-and-conquer, our model adapts the recursive-DCM3 decomposition method [Roshan, U., Moret, B.M.E., Williams, T.L., Warnow, T, 2004a. Performance of suptertree methods on various dataset decompositions. In: Binida-Emonds, O.R.P. (Eds.), Phylogenetic Supertrees: Combining Information to Reveal the Tree of Life, vol. 3 of Computational Biology, Kluwer Academics, pp. 301-328; Roshan, U., Moret, B.M.E., Williams, T.L., Warnow, T., 2004b. Rec-I-DCM3: A Fast Algorithmic Technique for reconstructing large phylogenetic trees, Proceedings of the IEEE Computational Systems Bioinformatics Conference (ICSB)] to divide datasets into smaller subproblems. It distributes computation load over multiple processors so that each processor constructs subtrees on each subproblem within a batch in parallel. It finally collects the resulting trees and merges them into a supertree. The proposed model is flexible as far as methods for dividing and merging datasets are concerned. We show that our method greatly reduces the computational time of the sequential version of the program. As a case study, our parallel approach only takes 22.1h on four processors to outperform the best score to date (Found at 123.7h by the Rec-I-DCM3 program [Roshan, U., Moret, B.M.E., Williams, T.L., Warnow, T, 2004a. Performance of suptertree methods on various dataset decompositions. In: Binida-Emonds, O.R.P. (Eds.), Phylogenetic Supertrees: Combining Information to Reveal the Tree of Life, vol. 3 of Computational Biology, Kluwer Academics, pp. 301-328; Roshan, U., Moret, B.M.E., Williams, T.L., Warnow, T., 2004b. Rec-I-DCM3: A Fast Algorithmic Technique for reconstructing large phylogenetic trees, Proceedings of the IEEE Computational Systems Bioinformatics Conference (ICSB)] on one dataset. Developed with the standard message-passing library, MPI, the program can be recompiled and run on any MIMD systems. 相似文献
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《液相色谱法及相关技术杂志》2012,35(2)
Abstract “CHROMATOGRAPHY OF ANTIBIOTICS”, G. H. Wagman & M. J. Weinstein, Elsevier Science Publishers, Amsterdam, 1984, 510pp., $113.50 (US). “STERIC EXCLUSION LIQUID CHROMATOGRAPHY OF POLYMERS”, J. Janca, Ed., Marcel Dekker, Inc., New York & Basel, 1984, 329pp., $55.00 (US). “CHROMATOGRAPHIC STUDIES OF BIOGENESIS OF PLANT VOLATILES”, P. Schreier, Dr. Alfred Huthig Verlag GmbH., Heidelberg, 1984, 165pp., $34.00 (US). 相似文献
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Michael Raessler 《Trends in analytical chemistry : TRAC》2011,30(11):1833-1843
This article summarizes the current methods of determination of non-structural carbohydrates (NSCs) in plant samples based on liquid chromatography (LC). NSCs comprise several types of carbohydrates: sugar alcohols (e.g., sorbitol), monosaccharides (e.g., glucose and fructose), disaccharides (e.g., sucrose), oligosaccharides (e.g., raffinose) and polysaccharides [e.g., starch and polyfructans (e.g., inulin)]. NSCs are important in plant metabolism and have to be strictly distinguished from all sorts of structural carbohydrates (e.g., polysaccharide cellulose) that make up the backbone of the plants. Consequently, preservation of structural carbohydrates is a crucial step during sample preparation for NSC determination and is therefore addressed.Sugar alcohols, monosaccharides, disaccharides and those oligosaccharides that are easily soluble in polar solvents can be analyzed directly by high-performance LC. They are also referred to as free carbohydrates (FCs).However, polysaccharides are generally submitted to hydrolyzation into monomers prior to their quantitative analysis. This can be done either chemically, using acids, or enzymatically - both methods are discussed. For identification and quantification of the NSCs after LC separation, the following detectors are used: pulsed amperometry, refractive index, evaporate light scattering and finally, mass spectrometry. 相似文献
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GC-MS analytical methods for the determination of personal-care products in water matrices 总被引:1,自引:0,他引:1
Maria Chiara Pietrogrande Giulia Basaglia 《Trends in analytical chemistry : TRAC》2007,26(11):1086-1094
This article discusses the more recent methods combining gas chromatography and mass spectrometry (GC-MS) for analysis of personal-care products (PCPs) in water matrices. We describe different procedures for sample extraction and preparation as well as different instrumental methods commonly used for these compounds. GC-MS and GC-tandem MS (GC-MS2), which are complementary to liquid chromatography combined with MS (LC-MS), allow identification and quantification of PCPs belonging to different classes with the sensitivity and the selectivity necessary for environmental monitoring. The compounds investigated include fragrances (e.g., nitro and polycyclic musks), antimicrobial compounds (e.g., triclosan), ultraviolet blockers (e.g., methylbenzylidene camphor), antioxidants and preservatives (e.g., phenols and p-hydroxybenzoic acid (parabens)) and insect repellents (e.g., N,N-diethyl-m-toluamide (DEET)). We critically review data in the literature by focusing attention on analytical methods devoted to simultaneous detection and quantification of structurally diverse pharmaceuticals and PCPs. 相似文献