共查询到19条相似文献,搜索用时 187 毫秒
1.
光透薄层光谱电化学法研究紫脲酸铵电还原过程 总被引:1,自引:0,他引:1
采用金网橱光透薄层电解池, 配合紫外可见光谱技术现场监测了有机染料紫脲酸铵的电还原过程。用光透薄层光谱电化学方法测定了紫脲酸铵在pH5.0醋酸盐缓冲溶液中的式电极电位和电子转移数。薄层循环伏安法和薄层光谱电化学法研究表明, 紫脲酸铵在金网栅电极上的还原为双电子转移不可逆过程, pH<8时, 还原产物双巴比士亚胺进一步分解为尿咪和巴比士酸。用双电位跃-计时吸收谱法研究了双巴比士亚胺在不同pH缓冲溶液中的分解动力学过程, 测定了拟-级反应动力学常数。 相似文献
2.
3,3′,5,5′-四甲基联苯胺(TMB)在不同 pH 的 B-R 缓冲溶液中有不同的电氧化行为. 文中以自制的 SnO2:F 膜光透薄层光谱电化学池对 TMB 的电氧化性质进行了研究. TMB 在 pH 2.0 至pH < 4.0 的 B-R 缓冲溶液中为一步两电子电氧化过程, 在 pH 4.0 ~ pH < 7.0 的 B-R 缓冲溶液中为分步的两个单电子氧化过程, 且在 pH 6.5时则先为分步的两个单电子过程, 随后其氧化产物进一步转化为偶氮化合物. 实验中应用了薄层循环伏安法、薄层循环伏安吸收法、薄层恒电位电解吸收光谱法、单电位阶跃计时吸收光谱法、双电位阶跃计时吸收光谱法、单电位阶跃开路弛豫计时吸收光谱法等技术; 测得了在各 pH 值的 B-R 缓冲溶液中 TMB 电氧化相应的克式量电位 E0′, 电子转移数 n 以及有关的化学反应速率常数. 相似文献
3.
3,3',5,5'-四甲基联苯胺(TMB)在不同pH的B-R缓冲溶液中有不同的电氧化行为.文中以自制的SnO2:F膜光透薄层光谱电化学池对TMB的电氧化性质进行了研究.TMB在pH 2.0至pH<4.0的B-R缓冲溶液中为一步两电子电氧化过程,在pH 4.0~pH<7.0的B-R缓冲溶液中为分步的两个单电子氧化过程,且在pH 6.5时则先为分步的两个单电子过程,随后其氧化产物进一步转化为偶氮化合物.实验中应用了薄层循环伏安法、薄层循环伏安吸收法、薄层恒电位电解吸收光谱法、单电位阶跃计时吸收光谱法、双电位阶跃计时吸收光谱法、单电位阶跃开路弛豫计时吸收光谱法等技术;测得了在各pH值的B-R缓冲溶液中TMB电氧化相应的克式量电位E0',电子转移数n以及有关的化学反应速率常数. 相似文献
4.
冰醋酸中肾上腺素的现场光谱电化学行为 总被引:1,自引:0,他引:1
采用以石墨为工作电极的长光程薄层光谱电化学池, 用循环伏安法、恒电位光谱法和单电位跃计时吸光度法,研究了肾上腺素(AD)在冰醋酸介质中的电子转移反应。结果表明:AD在冰醋酸介质中电氧化反应产物为肾上腺素醌,还原态和氧化态的扩散系数分别为 3. 98×10-6 cm2 /s和 3. 90×10-6 cm2 /s;电极反应的式量电极电位为 0. 632V(vs.SCE),式量异相电子转移速率常数为 7. 30×10-4cm/s;传递系数为 0. 15。 相似文献
5.
用双电位阶跃计时电流法,动电位扫描等电化学技术和红外光谱法系统测定了现场红外镜反射式电解池中的薄层厚度,电化学特性和光谱特性。结果表明,红外光谱电化学研究中的电解池存在定量的薄层电解效应。 相似文献
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3,3′,5,5′-四甲基联苯胺(TMB)在不同pH的B-R缓冲溶液中有不同的电氧化行为. 文中以自制的SnO2:F膜光透薄层光谱电化学池对TMB的电氧化性质进行了研究. TMB在pH 2.0至pH < 4.0 的B-R缓冲溶液中为一步两电子电氧化过程, 在pH 4.0 ~ pH < 7.0 的B-R缓冲溶液中为分步的两个单电子氧化过程, 且在pH 6.5时则先为分步的两个单电子过程, 随后其氧化产物进一步转化为偶氮化合物. 实验中应用了薄层循环伏安法、薄层循环伏安吸收法、薄层恒电位电解吸收光谱法、单电位阶跃计时吸收光谱法、双电位阶跃计时吸收光谱法、单电位阶跃开路弛豫计时吸收光谱法等技术; 测得了在各pH值的B-R缓冲溶液中TMB电氧化相应的克式量电位E0′, 电子转移数n以及有关的化学反应速率常数. 相似文献
8.
肌红蛋白在灿烂甲酚蓝修饰电极上的可逆电子传递反应 总被引:3,自引:1,他引:2
利用循环电位吸收法和电位阶跃计时吸收法在薄层电解池中研究了肌红蛋白在灿烂甲酚蓝(BCB)修饰电极上和BCB溶液中的电化学行为。实验表明肌红蛋白可以发生可逆的还原和氧化反应,完全还原和氧化分别需要20和100s, 氧化还原反应的标准速率常数被估算为5.6×10^-^4cm·s^-^1, 并且稳定性很好, 没有蛋白质变性反应发生。用光谱电化学方法测得该反应的标准电极电位和电子转移数与肌红蛋白相符。光电子能谱实验表明肌红蛋白没有吸附在BCB修饰电极上, 对BCB修饰电极促进肌红蛋白的电子转移机理作了初步探讨。 相似文献
9.
为了量化电极反应过程中液相组分和预吸附组分对总的氧化还原电流的贡献,采用双电势跃计时电流法,在长光程薄层电化学池中,测试了染料木黄酮在石墨-石蜡电极上的第一步氧化还原行为,在该反应体系的特征吸收波长259nm和286nm下,记录双电势跃计时吸光度数据;采用自编计算机程序对数据进行解析,导出了液相中的染料木黄酮及其氧化产物的计时电流曲线,从而提出了一种由光吸收信号获得双电势跃计时电流曲线的新方法。这种重构的计时电流曲线,对应于相应组分在反应过程中的液相浓度的变化,为氧化还原体系的动力学分析提供了更详细的信息。 相似文献
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间苯二胺的电化学及紫外-可见薄层光谱电化学研究 总被引:3,自引:0,他引:3
研究了间苯二胺(MPD)在金电极和SnO2;F膜电极上的循环伏安行为及在SnO2;F膜电极上的紫外-可见薄层光谱电化学性质.获得了间苯二胺在SnO2;F膜电极上电氧化的薄层恒电势电解-吸收光谱图,采用双对数法对紫外-可见薄层光谱电化学数据进行了处理.研究了间苯二胺的光谱及电化学性质,求得了间苯二胺的动力学修饰式量电位E0和αn等热力学参数. 相似文献
12.
Josef Salbeck 《Journal of Electroanalytical Chemistry》1992,340(1-2)
A combination cell to accomplish simultaneous electrochemical and spectroelectrochemical measurements under both thin-layer and semi-infinite diffusion conditions is described and characterized. Fibre optics and a reflective electrode are used to couple the cell to the spectrophotometer. This allows different electrode materials to be used. Moreover, the cell is thermostatically controlled and equipped with a magnetic stirrer, and can be used for temperatures down to −40°C.The application of electrochemical pulse and sweep techniques are demonstrated. Dynamic spectroelectrochemical techniques such as linear sweep and cyclic voltabsorptometry (LSVA and CVA) as well as the corresponding derivative voltabsorptometric techniques derivative linear voltabsorptometry (DLSVA) and derivative cyclic voltabsorptometry (DCVA) are also applicable under thin-layer conditions. DLSVA and DCVA are the optical analogues of linear sweep and cyclic voltammetry. No epoxy cement or other sealing compounds are required and the solution comes in contact with only quartz, Teflon and the electrodes. Under aprotic conditions the cell response is in accordance with theory down to a solution thickness of 15 μm, where rapid exhaustive electrolysis intrinsic to thin-layer electrochemistry can be achieved in less than 1 s.The electrochemical and spectroelectrochemical characterization of the cell demonstrated that this design is very well suited to different electrochemical pulse and sweep techniques with simultaneous spectroscopic characterization of reaction products under finite and semi-infinite diffusion conditions in organic solvents. This offers the opportunity for cross-correlations of the electrochemical and spectroscopic information, which should lead to more reliable results. The adjustment of different thin-layer thicknesses is highly reproducible and the exchange of the solution inside the thin-layer cavity with the bulk solution after each thin-layer experiment can be easily performed. The electrochemical behaviour of the cell is in accordance with theory for cyclovoltammetric measurements under both bulk and thin-layer conditions. Derivative voltabsorptometric techniques are applicable and the response of the cell is in accordance with theory, particularly under finite diffusion conditions. The use of a bifurcated optical fibre bundle allows a more flexible experimental arrangement, and the application of a triple split bundle for the investigation of light-sensitive electron-transfer compounds [34,35] is in progress. The third end of the optical fibre bundle will be used to apply additional selective irradiation to convert electron-transfer-active photochromic compounds inside the thin-layer cavity depending on the redox state.An additional aspect of the current investigations is the application of the present cell for electrogenerated chemiluminescence (ECL) [36,37]. The highly reflecting electrode and the integrated stirrer are advantageous for this type of measurement. Finally, further work is in progress to utilize the integrated temperature control of the cell for spectroelectrochemistry at low temperatures, particularly with more unusual solvents like liquid sulphur dioxide [38] and liquid dimethylamine [39]. 相似文献
13.
Xiang Qin LIN Liang Dong FENG 《中国化学快报》2006,17(5):703-706
It is well known that the iR compensation is very important in electrochemistry, especially in fast, ultra-fast and transient voltammetry for kinetic and mechanistic studies. The modern design of potentiostat is usually of the three-electrode system, in w… 相似文献
14.
The electrooxidation of 3,3′, 5,5′-tetramethylbenzidine (TMB) is dependent on the pH value of Britton-Robinson (B-R) buffer
solution. In this work, the electrooxidation behavior of TMB was investigated with a SnO2:F film optically transparent thin-layer
spectroelectrochemical cell. TMB underwent one two-electron electrooxidation process in the pH range from 2.0 to < 4.0, and
two successive one-electron electrooxidation processes in the pH range from 4.0 to < 7.0 in the B-R buffer solution. At pH
6.5, the electrooxidative product of TMB generated a subsequent chemical reaction to yield an azo compound. Several spectroelectrochemical
techniques, such as thin-layer cyclic voltammetry, thin-layer cyclic voltabsorptometry, thin-layer potential-controlled electrolysis
absorptometry, thin-layer single-potential-step chronoabsorptometry, thin-layer double-potential-step chronoabsorptometry,
thin-layer single-potential-step open-circuit relaxation chronoabsorptometry, were applied to this investigation. The formal
potential E0′ and the electron transfer number corresponding to the electrooxidation of TMB in B-R buffer solution, and the reaction rate
constant of the subsequent chemical reaction were determined. 相似文献
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16.
支链/环链烷氧基乙酸为离去配体的铂(Ⅱ)配合物的体外活性研究 总被引:1,自引:0,他引:1
合成了12个带支链/环链烷氧基乙酸为离去基团的顺铂类配合物,通过元素分析、红外光谱、核磁共振氢谱和质谱对配合物进行了表征。研究了所有化合物对人非小细胞肺癌A549、人肝癌细胞BEL-7402和人乳腺癌细胞MCF-7细胞系的体外抗肿瘤活性。测试结果表明,12个配合物中有5个对人乳腺癌细胞系MCF-7有较好的体外活性。其中化合物2(顺-二(异丙氧基乙酸根)·二氨合铂(Ⅱ))在所有的化合物中显示最高的活性,对所测3个细胞系都是如此。 相似文献
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18.
Christopher E. Dahm Dennis G. Peters Jacques Simonet 《Journal of Electroanalytical Chemistry》1996,410(2):163
Anodically polymerized films of nickel salen formed on glassy carbon, optically transparent tin oxide, and platinum electrodes in acetonitrile containing tetramethylammonium tetrafluoroborate have been examined by means of cyclic voltammetry, thin-layer voltammetry, spectroelectrochemistry, and scanning electron microscopy. With the aid of thin-layer voltammetry, it has been confirmed that the global oxidative polymerization of nickel(II) salen involves three electrons per monomer. Polymerization proceeds through two distinct phases, the formation of which depend on the potential. Once the polymer film has been formed, the anodic process consists of the reversible one-electron nickel(III)/nickel(II) redox couple. Cyclic voltammetry along with spectroelectrochemistry has been employed to probe the roles of the nickel(III)/nickel(II) and nickel(II)/nickel(I) redox couples in the electrochemical response of the polymer film as well as the interconversion of the different oxidation states of nickel. 相似文献
19.
JIAO Kui YANG Tao & NIU Shuyan . College of Chemistry Molecular Engineering Qingdao University of Science Technology Qingdao China . College of Chemistry Chemical Engineering Ocean University of China Qingdao China Correspondence should be addressed to Jiao Kui 《中国科学B辑(英文版)》2004,47(4)
3,3',5,5'-tetramethylbenzidine (TMB) is a sensi-tive commonly-used substrate of the spectrophotomet-ric enzyme-linked immunosorbent assay (ELISA) as well as the electrochemical enzyme-linked immuno-assay[1,2]. It is more stable and of lower reagent blank than another sensitive commonly-used substrate, o-phenylenediamine. TMB is also the substrate of the most ELISA kits for clinical examination. The TMB- H2O2-horseradish peroxidase (HRP) voltammetric en-zyme immunoassay system has very… 相似文献