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阻抑-催化褪色光度法测定痕量锑(Ⅲ) 总被引:6,自引:0,他引:6
1 引 言 测定Sb(Ⅲ)有KBrO3-甲基橙褪色光度法、荧光酮衍生物光度法、Sb(Ⅲ)-乙基罗丹明B和Sb(Ⅲ)-甲基橙-溴化十六烷基三甲铵(CTMAB)络合光度法等,但诸方法的ε为 104~105L·mol-1·cm-1,灵敏度不高,操作较烦。实验表明:碱性介质中,Sb(Ⅲ)能阻抑 CTMAB催化结晶紫(CV)碱褪色反应,由此建立了阻抑-催化褪色光度法测定痕量锑(Ⅲ)新方法(ε590=2.0× 107L·mol-1·cm-1)。该方法灵敏度高,操作简便,重现性好。2 实验部分2.1 主要试剂与仪器 … 相似文献
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反相高效液相色谱法测定食品中水溶性维生素的含量 总被引:14,自引:1,他引:14
采用反相色谱法同时测定食品中水溶性维生素(Vitamin)C、B5、B6、B1、B2和B12的含量,PC810/S2504(4.0mm×250mm,10μm)柱,0.1mol/L甲酸铵甲酸溶液(pH=4.5,含0.4%二乙胺)+甲醇(75+25)为流动相,流速1mL/min,UV254nm,12min内实现了良好分离,乙酰苯胺为内标物。苹果及强化奶粉中维生素平均回收率分别为92.50%~105.60%和95.00%~102.80%,该法操作简便、迅速、可靠、测试费用低。 相似文献
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维生素B的同时测定——神经网络与紫外光谱法 总被引:9,自引:4,他引:9
研究了反向传播神经网络(BPNN)及改进算法,经比较发现BPNN在某些方面优于滤波分辨及多元校正,将其应用于多元分析及光谱定量,可不经分离同时测定B族维生素,操作简便,结果良好,从而开发一种多组分同时光谱测定新方法。 相似文献
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报道了山西西山焦煤飞灰,在小型循环流化床气化反应器,以二氧化碳为气化介质,在不同操作条件下(气速,固体循环速率)的气化反应,研究结果表明,CO出口浓度及碳转化率随着CFB操作气速减小,固体颗粒循环速率的增加而增加,即在CFB床中,提高气体,固体停留时间(床内固体颗粒浓度)有利于CFB气化的进行,CO浓度及碳转化率沿床高的变化趋势与床内颗粒浓度分布一致。 相似文献
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BaFClxGBr1—X:Sm体系的热释发光及其归属讨论 总被引:1,自引:0,他引:1
通过对BaFClxBr1-x:Sm(0≤x≤1)体系热释发光的研究,发现前人对BaFX(X=Cl,Br)晶体热释发光的归属有误。结合多种技术的研究给出了正确的归属:BaFClxBr1-x:Sm的第一、二、三个热释峰分别归属于F(F^-),F(Cl^-)和F(Br^-)心;BaFX晶体的第一、二个热释峰分别归于F(F^-)和F(X^-)心。论证了结果的正确性,并分析了前人归属错误的可能原因。 相似文献
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研究了N2H4在间-四(邻-硝基苯基)四苯并卟啉铁(Ⅲ)、钴(Ⅱ)、锌(Ⅱ)和镍(Ⅱ)配合物[MTP(о-NO2)TBP,简称MTBP]修饰石墨电极上的催化电氧化反应,测得该系列金属四苯并卟啉的催化活性的顺序为Co(Ⅱ)TBP>ClFe(Ⅲ)TBP>Ni(Ⅱ)TBP>Zn(Ⅱ)TBP≈石墨,考察了Co(Ⅱ)TBP和ClFe(Ⅲ)TBP催化联氨电氧化反应的动力学过程。结果表明,OH^-和N2H4在C 相似文献
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A. V. Barbov M. V. Shepelev D. V. Filippov M. V. Ulitin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(9):1605-1610
The effects of the nature and composition of solvents on the thermodynamic characteristics of the adsorption states of hydrogen
on nickel were studied. The adsorption can be described in terms of the thermodynamic model of a surface with a discrete nonhomogeneity
for three individual forms of adsorbed hydrogen. The thermodynamic characteristics of the individual forms of hydrogen adsorbed
on porous nickel from aqueous solutions of sodium hydroxide, dimethylformamide, methanol, and ethanol were determined. 相似文献
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B. Vishalakshi 《Journal of polymer science. Part A, Polymer chemistry》1995,33(3):365-371
The interaction of various structurally different water-soluble cationic polyelectrolytes with methyl orange, an anionic dye, has been studied. The changes in the UV-Vis spectra of methyl orange in the presence of methyl and benzyl quaternized polyvinylpyridines and trialkylammonium and triphenylphosphonium salts of polyvinylbenzyl chloride have been used to investigate the effect of the structure on the dye-binding characteristics of the polycations. The results are interpreted in the light of a simple theory of cooperative binding to a linear lattice. The extent of binding of the dye aggregates on the polymers has been calculated. The binding ability of the above-mentioned polyelectrolytes has been found to depend on the nature of the substituent on the polycation. The contribution of the coulombic forces on binding of the dye by these polymers has been emphasized. © 1995 John Wiley & Sons, Inc. 相似文献
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The influence of the structure of the alcoholic modifier of the mobile phase on the liquid chromatographic separation of the optical isomers of nadolol on a Pirkle-type chiral stationary phase was investigated. The isomers were separated as their chiral 1-naphthylureides on a column consisting of 3,5-dinitrobenzoyl-
-leucine covalently bound to 3-μm aminopropylsilica, using an eluent consisting of n-hexane modified with an alcohol. A number of straight-chain, branched and unsaturated alcohols with carbon numbers ranging from 1 to 8 were evaluated. The choice of alcohol influenced both retention and selectivity, with optimum stereoselectivity being observed for C3. The alcoholic modifiers selectively affected the retention and resolution of the two pairs of enantiomers that constitute nadolol. Thus chromatograms displaying two, three or four peaks could be obtained, depending on which modifier was employed. The best separation of all four isomers was achieved with ethanol as the modifier. 相似文献
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V. P. Lezina N. A. Andronova L. D. Smirnov K. M. Dyumaev 《Chemistry of Heterocyclic Compounds》1971,7(11):1438-1440
The dependence of the chemical shifts of the ring protons on the pH of the medium for a number of 4-hydroxyquinoline derivatives was studied by means of PMR spectroscopy. The dipolar and uncharged hydroxy forms exist in equilibrium in aqueous solutions. The effect of intramolecular hydrogen bonding on the character of the dependence of the chemical shift on the pH of the medium in the case of 3-piperidinomethyl-4-hydroxyisoquinoline was investigated. The possibility of the separate protonation of the ring nitrogen and the side-chain nitrogen in 3-piperidinomethyl-4-hydroxyisoquinoline was established. The distribution of the -electron density in 4-hydroxyisoquinoline is in good agreement with its chemical behavior.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1546–1549, November, 1971 相似文献
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Laura M. Cubillana-Aguilera José M. Palacios-Santander Ignacio Naranjo-Rodríguez José Luis Hidalgo-Hidalgo-de-Cisneros 《Journal of Sol-Gel Science and Technology》2006,40(1):55-64
In this paper, the influence of carbon particles size on structure and on electrochemical and physical properties of the Sonogel-Carbon
electrodes, with respect to Sonogel materials without graphite, have been studied. The materials have been characterized electrochemical
and structurally; several Sonogel-Carbon materials were synthesized using different types of graphite powder as massive modifiers,
adding in some cases other modifiers, such as octadecyl (C18) and polyethyleneglycol (PEG). Differential pulse voltammetry
and cyclic voltammetry were the voltammetric techniques employed to evaluate the electrochemical behaviour; Scanning Electron
Microscopy, Energy Dispersive Spectroscopy and Infrared Spectroscopy were the techniques employed to realize the superficial/structural
characterization of the materials. The results obtained in both studies were very useful to explain the structure of the Sonogel-Carbon
materials. Furthermore, they allowed to conclude that electrodes based on RW-B and UF graphites show very similar electrochemical
behaviours and internal structures. 相似文献
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P. D. Vorob’ev N. P. Krut’ko E. V. Vorob’eva D. V. Cherednichenko I. I. Basalyga 《Colloid Journal》2007,69(5):552-556
Peculiarities of the formation of polyelectrolyte complexes based on cationic and anionic copolymers of acrylamide having different macromolecule charge densities on the surfaces of kaolin particles in highly concentrated salt solution are investigated. The interactions of the copolymers with the clay particle surface and with each other are studied by electrokinetic and IR spectroscopy methods. The rheological properties of kaolin suspensions are investigated in a salt solution in the presence of the polyelectrolytes. The flocculation ability of the polyelectrolytes and their binary mixtures with respect to clay-salt dispersion is estimated. The mechanism for the formation of polyelectrolyte complexes on the surface of clay particles is discussed. It is shown that the complexation of oppositely charged polyelectrolytes on the surfaces of clay particles intensifies the flocculation of clay-salt dispersions. 相似文献
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S. A. Mechkovskii N. A. Sankevich A. N. Trifonova 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2008,82(8):1273-1276
The influence of the coion and the ratio between the water-acetone binary solvent components on cation and anion exchange on sulfo-and aminostyrene ion exchangers with a medium degree of cross-linking were studied. The dependence of selectivity coefficients on the degree of ionite filling by the desired component was found to vary substantially as the composition of the solvent and the radius of the cation changed. 相似文献
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《Analytical letters》2012,45(4):303-309
Abstract The effect of the anion of the salt background of the aqueous phase on the extraction of the 8-oxyquinolinate of germanium has been investigated The anion effect is associated with the change in ionization constants and distribution of 8-oxyquinoline The degree of anion influence depends on the reagent concentration. 相似文献