共查询到20条相似文献,搜索用时 93 毫秒
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多廿醇是从制糖滤泥中分离得到的一种高级脂肪伯醇天然混合物,其化学组成分析未见报道。本文采用气相色谱法(GC)和气相色谱/质谱法(GC/MS),对其组分和结构进行了分析和鉴定。 相似文献
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化学吸附纤维制备、性能及应用研究进展 总被引:20,自引:0,他引:20
综述了20年来作者对化学吸附纤维(离子交换、螯合)制备、性能及应用研究结果.包括已发表的文章、未全丈发表的会议报告及尚未发表的研究结果.化学吸附纤维制备研究:基体纤维有聚丙烯、聚丙烯腈、聚氯乙烯、聚乙烯醇纤维,采用方法有辐射引发、化学引发、大分子化学转化,研制了强酸、弱酸性阳离子交换纤维;强碱、弱碱性阴离子交换纤维、螯合纤维.应用研究:对金、铀、重金属等离子的吸附和分离;在填充床电渗析中的应用、吸附气体中H2S、CO2、NH3、HCl、SO2,以及CO2、H2S的分离;废水处理等. 相似文献
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环境样品中硝基苯类化合物的分析方法研究进展 总被引:4,自引:0,他引:4
主要介绍了我国近年来在环境样品中硝基苯类化合物的分析研究进展,内容包括:光度法(还原-偶氮光度法、阻抑动力学光度法、化学计量学分光光度法、人工神经网络-分光光度法)、气相色谱法(固相微萃取-毛细管气相色谱法、树脂吸附-气相色谱法、液-液微萃取气相色谱法、超声萃取-气相色谱法)、高效液相色谱法(反相高效液相色谱法、固相萃取-高效液相色谱法)和极谱法等分析方法。 相似文献
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本工作研究了吸附剂、催化剂等固体添加物混入微孔聚砜膜中对C_1化学用原料气-H_2和CO的选择透气性的影响,普遍的结果是显著地提高了膜对气体的分离因子,且与吸附剂、催化剂的化学、物理性质有一定关系。因此,气体的渗透过程除了有诺森流和粘性流外,还可能生成吸附态过渡络合物,影响气体的吸附-脱附能力而提高了分离因子,提出了过渡吸附态的气体促进输送机理。 相似文献
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The application of high-field Fourier transform nuclear magnetic resonance (NMR) spectroscopy to the analysis of biological fluids such as urine, plasma and bile is described. Applications include areas such as clinical chemistry, experimental and clinical toxicology and drug metabolism studies. In the case of proton NMR some means of attenuating or eliminating the interference due to water protons is required and suitable strategies for achieving this are discussed. The use of 2-dimensional NMR or solid-phase extraction/chromatography to enable the identification of unknowns is discussed and the potential usefulness of 19F NMR for studying the metabolism of fluorinated xenobiotics is highlighted. 相似文献
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Protein-based liquid chromatography stationary phases are used in bioaffinity chromatography for studying drug-protein interactions, the determination of binding affinities, competitive and allosteric interactions, as well as for studying protein-protein interactions. This review addresses the development and characterization of protein-based stationary phase, and the application of these phases using frontal and zonal chromatography techniques. The approach will be illustrated using immobilized heat shock protein 90α and the immobilized estrogen related receptor stationary phases. In addition, the review discusses the use of the protein-coated magnetic beads for ligand and protein fishing as well as for the identification of unknown ligands from cellular or botanical extracts. 相似文献
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Choi YB Ko MH Shin CH Kim KS Hong KM Paik MK Park DE 《Experimental & molecular medicine》2005,37(3):155-160
The methylation of a 23-kDa nuclear protein increased after partial hepatectomy and methylation returned to basal levels after the initial stage of regeneration. The methylating enzyme was partially purified from rat liver by ammonium sulfate precipitation, DEAE-anion exchange chromatography and Butyl-Sepharose chromatography. The 23-kDa protein was purified from a nuclear fraction of liver tissue with SP-Sepharose. When the 23-kDa protein was methylated with the partially purified methyltransferase and analyzed on C(18) high performance liquid chromatography (HPLC), the methylated acceptor amino acid was monomethyl lysine (MML). Previously, only arginine N-methylation of specific substrate proteins has been reported during liver regeneration. However, in this report, we found that lysine N-methylation increased during early hepatic regeneration, suggesting that lysine N-methylation of the 23-kDa nuclear protein may play a functional role in hepatic regeneration. The methyltransferase did not methylate other proteins such as histones, hnRNPA1, or cytochrome C, suggesting the enzyme is a 23-kDa nuclear protein- specific lysine N-methyltransferase. 相似文献
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In studying the reactions of thermal degradation of solid samples more information can be obtained by correlation gas chromatography than by conventional pyrolysis gas chromatography. This is due to a multiplex character of the method leading to a rapid decrease in detection limit. 相似文献
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Masao Ikeda Takashi Nakamura Yu Nagase Koji Ikeda Yoshiro Sekine 《Journal of polymer science. Part A, Polymer chemistry》1981,19(10):2595-2607
For the purpose of studying the mechanism of thermal degradation of poly[(tetramethyl-p-silphenylene) Siloxane] (poly TMPS) a series of polymers with silphenylene and siloxane bonds in the main chain were prepared and subjected to thermogravimetry (TG) and pyrolysis study. Analyses of products from poly TMPS degradation (in vacuum at a constant temperature) by gas chromatography (GC), infrared (IR), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry (GC–MS) revealed that degradation occurs at the silphenylene bonds. The TG curves obtained in He for heating rates of 1,2,2.5,7.5, and 10°C/min were analyzed by the Ozawa method; activation energies of 39 ± 1 and 45 ± 2 kcal/mol were obtained respectively for the initial cleavage of the methyl side group and the later-stage scission of the main-chain silphenylene bond which leads to a major weight loss. The results agree with those obtained for other structurally similar polymers. 相似文献
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Adrián Mejía-González Sandra Zetina Manuel E. Espinosa-Pesqueira 《International Journal of Polymer Analysis and Characterization》2017,22(6):473-482
A large part of Mexican artistic heritage was created with artists’ acrylic emulsion paints, so it is crucial to investigate their composition, behavior, and decay. Acrylic films are complex chemical systems combining organic and inorganic compounds; therefore, the degradation studies require a variety of techniques. We characterize three acrylic films before and after ultraviolet aging. The relative composition of the polymer matrix was studied by nuclear magnetic resonance, pyrolysis—gas chromatography—mass spectrometry and direct analysis in real time mass spectrometry with direct analysis in real time. The inorganic compounds and surfaces were characterized by microscopic techniques, such as digital microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and micro X-ray diffraction. The combined use of these techniques proved to be effective for an in-depth study of the acrylic painting degradation process. The main results were the gradual degradation for the organic surfactant and the loss of inorganic aggregates (talc and carbonates), that led to the disruption of the paint film, which points out the importance of studying the role and interaction of all compounds. 相似文献
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Oxygenated neutral constituents of a tumor-inhibiting fraction of cigarette smoke condensate were separated from interfering phenolic compounds by a combination of silicic acid and gel chromatography. Silicic acid adsorption and Bio-Beads gel chromatography separated aliphatic from aromatic ketones, and gel chromatography on Sephadex LH-20 resolved aromatic ketones from phenols. Identifications were achieved by studying individual fractions by g.c. and g.c.—m.s. 相似文献
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Margherita Albano Emma Barchiesi Roberto Biancardi Marco Dossi Giuliana Geniram Paola Vaccarono 《Macromolecular Symposia》2013,324(1):41-48
Summary: In this work an investigation of the chain end groups produced in the free radical copolymerization of vinilydene fluoride (VDF) and hexafluoropropylene (HFP) is performed. Type and amount of chain end groups are evaluated by a meticulous analytical characterization of VDF/HFP copolymer. At first pulsed gradient spin-echo nuclear magnetic resonance (spin-echo NMR) is used to identify all the chain end groups also at very low concentration (equal to 0.1 mmol · Kg−1). The instrument sensitivity is increased of an order of magnitude in comparison with the traditional NMR. Moreover potentiometric titration and ion chromatography (IC) are also used to study the chain end groups and, as a consequence, the nature and the amount of the acidity showed by the polymer chains. In details two intensity of acidity are detected by potentiometric titration, namely strong and weak. The strong acidity is associated to the presence of residual surfactant and can be removed washing the polymer, while the weak acidity is due to free molecules of fluoride acid (HF). The standard ion chromatography facility is properly modified to quantify the fluoride in the polymer matrix without any pre extraction in water. Thanks to this the HF concentration in the polymer is evaluated with high accuracy. A detailed kinetic scheme for the VDF/HFP polymerization is also proposed taking into account all the findings obtained studying the chain end groups. 相似文献
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A. N. Kuzmenko I. I. Krasnyuk Jr. A. V. Pirogov 《Moscow University Chemistry Bulletin》2014,69(4):163-167
Two complementary chromatographic methods, viz., ion-exclusion chromatography and gas-liquid chromatography, are suggested for studying the chemical composition and the standardization of medicinal-plant raw materials and plant mixtures. An algorithm for selecting one of two methods, which takes into account the component composition in plant mixtures, as well as the classification of marker sub-stances according to the degree of their occurrence in specific types of medicinal-plant raw materials, are proposed. 相似文献