共查询到19条相似文献,搜索用时 750 毫秒
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用混合床离子色谱柱同时测定阴阳离子 总被引:3,自引:0,他引:3
将阴离子交换树脂和阳离子交换换树脂混合后填充在一根色谱柱中,即所谓阴阳离子混合床柱。研究了阴阳离子在此混合柱上的保留行为并探讨了其保留机理。 相似文献
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水汽系统氢电导率监测用氢交换柱附加误差超标是造成氢电导率测量不准确的主要原因,而氢交换柱附加误差超标主要源于阳树脂的再生度低。理论分析和研究结果表明,氢交换柱附加误差与阳树脂再生度及水样Cl-浓度均有关系,再生度越低,Cl-浓度越高,氢交换柱附加误差就越大。对于超临界水汽系统氢电导率测量用氢交换柱,为了保证附加误差满足不大于5%的标准要求,建议控制树脂再生度在85%以上。阳树脂再生度取决于再生工艺,动态再生和电再生的效果要比静态浸泡再生好,可以保证树脂的再生度和氢交换柱的附加误差满足要求。 相似文献
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采用浸泡方法分别研究了氨、乙醇胺、吗啉对阳离子交换树脂性能的影响。利用光学显微镜观察浸泡前后阳离子交换树脂的形貌。55℃下,分别在pH值为9.3的氨、乙醇胺及吗啉的溶液中浸泡不同时间后离子交换树脂的总交换容量、含水率、湿视密度、湿真密度变化均不明显。以3种不同浓度(0.9mol/L、1.4mol/L、1.9mol/L)的氨、乙醇胺及吗啉的溶液分别浸泡离子交换树脂,浸泡后总交换容量、含水率、湿视密度、湿真密度的变化也不大。在恒定pH值与不同浓度碱化溶液中浸泡后,黑琥珀色半透明离子交换树脂的颜色均变浅。实验结果表明有机胺对凝胶型阳离子交换树脂的性能和形貌影响不大。 相似文献
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标题的装置包括装有预涂中空纤维的过滤器的过滤一脱盐箱,一个装填离子交换树脂的柱塔,用于监测徨水电导率或CL~-浓度的装置和依靠来自监测器的反馈信号来控制离子交换树脂数值的装置。阴离子交换树脂对阳离子交换树脂的数值的装置。阴离子交换树脂对阳离子交换树脂的混合比例控制在>0.5:1,离子交换树脂的平 相似文献
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以N-Boc-D-谷氨酸和不同链长的烷基氨为原料,1-乙基-3-(3-二甲氨基丙基)碳二亚胺盐酸盐和1-羟基苯并三唑为缩合剂制得N,N′-双十二(双十四,双十六)-D-Boc-谷氨酸二酰胺(DBGn); DBGn在二氯甲烷中用三氟乙酸水解合成了N,N′-双十二(双十四,双十六)-D-谷氨酸二酰胺(DGn),其结构经1H NMR和MALDI-TOF-MS确证。采用FT-IR, SEM和XRD研究了DGn在不同溶剂中的成胶性能。结果表明:Boc基团之间的氢键相互作用和长烷基链之间的疏水作用有利于凝胶的形成。 相似文献
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Glutamine and gamma-aminobutyric acid (GABA), formed from glutamic acid in crude tissue extracts by glutamine synthetase and glutamic acid decarboxylase respectively, were separated by derivatization with dansyl chloride followed by reversed-phase high-performance liquid chromatography on the Altex Ultrasphere ODS-5 column. The mobile phase was a gradient of 100 mM potassium dihydrogen phosphate (pH 2.1) with 0-40% acetonitrile. The amounts of glutamine and GABA formed from glutamic acid were determined under different reaction conditions. 相似文献
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The separation of amino acids has been achieved on a short column of Chromo-Beads C2 resin, with a lithium gradient-elution system. The analysis took 8 h. The separation of asparagine and glutamine from glutamic acid was highly dependent on the sample pH and on the methanol concentration in the first buffer of the gradient. The method has been applied to analysis of human plasma and granulocytes for amino acids. 相似文献
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Zhang Q Wysocki VH Scaraffia PY Wells MA 《Journal of the American Society for Mass Spectrometry》2005,16(7):1192-1203
A fragmentation mechanism for the neutral loss of 73 Da from dimethylformamidine glutamine isobutyl ester is investigated. Understanding this mechanism will allow to improve the identification and quantification of 15N-labeled and unlabeled glutamine and the distinguishing of glutamine and glutamic acid by electrospray ionization (ESI)-tandem mass spectrometry. Before mass spectrometry analysis, glutamine and glutamic acid are derivatized with dimethylformamide dimethyl acetal and isobutanol to form dimethylformamidine isobutyl ester. Derivatization conditions are modified based on an existing method to ensure complete derivatization of glutamic acid and to prevent the hydrolysis of glutamine. The fragmentation mechanism of dimethylformamidine glutamine isobutyl ester is studied and possible fragmentation pathways are proposed. Based on the fragmentation mechanism, a quantification method is developed to quantify both 15N-labeled and unlabeled glutamine and glutamic acid at a series of different neutral losses by performing multiple-reaction monitoring (MRM) scans in a triple-quadrupole mass spectrometer. Labeled glutamine includes 15N-amide labeled, 15N-amine labeled glutamine and glutamine 15N-labeled at both amide and amine positions. Deuterium labeled glutamine and glutamic acid are used as internal standards. Isotope effects are characterized for 15N labeled and deuterium labeled glutamine. It is found that the same method can be used to distinguish aspartic acid from asparagine. This study will improve the application of MS/MS for amino acid quantification and stable isotope labeling metabolism studies. 相似文献
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Starting from copolymerization of acrylonitrile and divinylbenzene by emulsion polymerization technique, a macroporous, crosslinked polyacrylonitrile copolymer was synthesized. The nitrile groups on the copolymer resin were converted into carboxylic acid groups by hydrolysis with strong alkaline solution of sodium hydroxide to obtain the resin matrix with carboxylic acid groups. A new chelating ion exchange resin containing alkylthioglycolate was prepared by esterification of carboxylic acid groups on the resin matrix and thioglycolic acid with 1,6-hexanediol as binding part. After studies of the basic characters, ion exchange ability, exchange rate and acidity of the medium, it was found that the new resin obtaind was highly selective for silver(I), mercury(II), gold(III) and bismuth(III) in acidic-aqueous solution. Separation of these metal ions from each other and concentration of these metal ions from very dilute solution were studied by liquid chromatography using a short column of this new resin. The analytical applications of this new resin are reported. 相似文献
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ShenJiyu WangQinyu 《反应性高分子(英文版)》1995,4(1):45-52
The feasibility of recovering glutamic acid by ion exchange method with macroporous resins was investigated.Their adsorption properties in stati state and the effective factors,such as pH,concentration of eeed and the ratio of ammonium ion to glutamic acid,were systematically explored.The best condition of separating glutamic acid from mother liquid were obtained. 相似文献
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STUDYONTHESEPARATIONOFGLUTAMICACIDBYION-EXCHANGEShenJinyu;WangQinyu(DepartmentofChemicalEngineering,TsinghuaUniversity,Beijin... 相似文献
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《液相色谱法及相关技术杂志》2012,35(11):2261-2266
Abstract Dansylated glutamic acid, glutamine and γ-amino butyric acid (GABA) show maximum absorption at 221 nm. Using this wavelength, the detection limits for dansylated amino acids studied by reversed-phase HPLC are similar to those reported by fluorescence. This technique was used to look foe the presence of glutamic acid and its metabolites in human serum. Glutamic acid and glutamine were present in significant amounts and their levels were 2.5 and 6.1 nmoles/ml respetively, while GABA was present in trace amounts, less than 0.3 nmoles/ml. 相似文献
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离子交换法提取谷氨酸的研究 总被引:4,自引:0,他引:4
本文就离子交换法提取谷氨酸树脂的筛选,不同树脂对发酵液中谷氨酸静态吸附性能及其影响因素进行了系统地研究.旨在探索离子交换法提取谷氨酸的最佳工艺条件和开发新的离子交换树脂. 相似文献
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Amino acid was mixed with silica and tetramethylammonium hydroxide (TMAH) to favor pyrolysis of amino acid monomer. The pyrolysis products formed from amino acid monomer were using GC/MS and GC. 20 amino acids of alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine were analyzed. The pyrolysis products were divided into cyclic and non-cyclic products. Among the 20 amino acids, arginine, asparagine, glutamic acid, glutamine, histidine, lysine, and phenylalanine generated cyclic pyrolysis products of the monomer. New cyclic pyrolysis products were formed by isolation of amino acid monomers. They commonly had polar side functional groups to 5-, 6-, or 7-membered ring structure. Arginine, asparagine, glutamic acid, glutamine, histidine, and phenylalanine generated only 5- or 6-membered ring products. However, lysine generated both 6- and 7-membered ring compounds. Variations of the relative intensities of the cyclic pyrolysis products with the pyrolysis temperature and amino acid concentration were also investigated. 相似文献