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71.
离子选择电极—流动注射分析法动力学测定葡萄糖存在下的果糖 总被引:3,自引:0,他引:3
本文将离子电极与流动注射分析相结合,利用30℃下,在强碱性介质中,果糖和葡萄糖与2,4-二硝基酚钠反应速度明显差异,动力学测定了葡萄糖存在下果糖的含量。自制了2,4-二硝基酚电极作为动力学电位测定用的工作电极。本法测定果糖的范围为0.02~1.00mol/L,其RSD为4.0%~4.9%,RE为1.0~5.0%;当C葡/C果≤3倍时,葡萄糖的干扰不超过5%;本法也曾成功地用于果葡萄浆测定,其RSD 相似文献
72.
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74.
Gejihu De Weiping Qin Jisen Zhang Yan Wang Chunyan Cao Yang Cui 《Journal of solid state chemistry》2006,179(3):955-958
In this work, we used the hydrothermal method to synthesize Eu3+ ion-doped cubic BaF2 nanorods, which is a luminescent material. The clubbed structures were well crystallized and exhibited face-centred cubic structures, as indicated by powder X-ray diffraction, scanning electron microscopy, electron diffraction, and transmission electron microscopy. The luminescent properties were studied, and local symmetry surrounding Eu3+ ions and electronic transition processes included. The results indicated that Eu3+ occupied only one C4ν site in nanorods. 相似文献
75.
Zeolite T membranes were synthesized on tubular porous mullite tubes by hydrothermal synthesis. The membranes selectively permeated carbon dioxide from CO2/CH4 and CO2/N2 mixtures with high separation performances, which were due to combined effects of molecular sieving and competitive adsorption. 相似文献
76.
Yunhui Zhai Xijun Chang Yuemei Cui Ning Lian Shoujun Lai Hong Zhen Qun He 《Mikrochimica acta》2006,154(3-4):253-259
A rapid, selective method that utilize 4-(2-Pyridylazo)-resorcinol (PAR)-modified nanometer SiO2 (nanometer SiO2–PAR) as a new solid-phase extractant for preconcentration of trace mercury (II) has been developed. The adsorption property
of nanometer SiO2–PAR for metal ions was studied by selectively extracting different metal ions from aqueous solutions. The results revealed
an excellent affinity of the nanometer SiO2–PAR for mercury (II) in presence of interfering metal ions at pH 4. The main parameters of solid-phase extraction such as
shaking time, elution and sample dilution effect were studied. The extractant shows rapid kinetic sorption, and the adsorption
equilibrium of mercury (II) on nanometer SiO2–PAR was achieved in less than 2 min. The adsorbed mercury (II) was easily eluted by 4 mL of 6 mol L−1 HCl. The maximum preconcentration factor was 50. The maximum static adsorption capacity was 276 μmol g−1 at pH 4. The detection limit (3σ) was 0.43 μg L−1 for cold vapor atomic absorption spectrometry (CVAAS), and the relative standard deviation of the eight replicate determinations
was 2.4% for the determination of 2.0 μg of Hg(II) in 100 mL water sample. The method was applied to the determination of
trace mercury (II) in sample solutions with satisfactory results. 相似文献
77.
Ye S Zhou W Abe M Nishida T Cui L Uosaki K Osawa M Sasaki Y 《Journal of the American Chemical Society》2004,126(24):7434-7435
A highly selective ligand exchange reaction is realized in the self-assembled monolayer (SAM) of a triruthenium cluster on a gold electrode surface under precise electrochemical potential control. CO as well as NO molecules, which are known to play key roles in many chemical, biological, and environmental systems, can be efficiently introduced into the SAM by electrochemically tuning the electronic state of the Ru site. These unique surface reactions are more convenient and efficient than conventional ligand exchange reactions in solution and could be used for the elucidation of the electron-transfer mechanism in a biological system as well as in the development of molecular sensors and devices. 相似文献
78.
<正> 前文我们报告了含有芳香叔胺基的丙烯酸酯、甲基丙烯酸-4-N,N-二甲氨基苄酯(DMABMA)在过氧化二月桂酰(LPO)引发下的聚合动力学。从所得的聚合速度方程式及低的聚合活化能,认为DMABMA与LPO形成氧化还原体系而使DMABMA聚合,在本文第Ⅳ报中报道了DMABMA不仅能引发甲基丙烯酸甲酯的聚合,还参与聚甲基丙烯酸甲酯的链中,因此称这种既能参与引发聚合反应,又参与聚合物链中的引发“引发剂单体(initiatomer)”。这种含有可聚合胺引发体系的优点是,用于丙烯酸酯类医用 相似文献
79.
Li H Li Y Zhai J Cui G Liu H Xiao S Liu Y Lu F Jiang L Zhu D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(24):6031-6038
A novel, water-soluble, cationic PPV derivative poly[(2,5-bis(3-bromotrimethylammoniopropoxy)-phenylene-1,4-divinylene)-alt-1,4-(2,5-bis(2-(2-hydroxyethoxy)ethoxy))phenylene vinylene] (BH-PPV) has been synthesized by a Heck coupling reaction. Multilayered assemblies of the BH-PPV and the sodium salt of hexa(sulfobutyl)fullerenes (C(60)-HS) were fabricated successfully by an alternate deposition technique. The multilayer structures were studied by UV/Vis spectroscopy, small angle X-ray diffraction, and atomic force microscopy. The photoinduced charge transfer property of the self-assembled multilayer film was also measured by a three-electrode cell technique. A steady and rapid cathodic 5.5 microA cm(-2) photocurrent response was measured as the irradiation of the multilayer film was switched on and off. Importantly, the response of on/off cycling is prompt and reproducible. A possible mechanism for the electron-transfer process is proposed. 相似文献
80.
本文提出了富烯碳原子簇的石墨层间闭合形成机理,由该机理推出的许多结果与实验事实符合很好。我们认为碳原子簇自由基的快速淬灭及其淬灭速度是富烯碳原子簇形成及其丰度的决定因素。由此得出富烯碳原子簇在给定实验条件下产生的必然性,并预言不同大小的富烯碳原子簇可以通过优化实验条件选择性地合成。 相似文献