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硫醇分子链长对氧化还原自组装多层膜电化学行为影响的初步研究(英文) 总被引:1,自引:0,他引:1
以烷基硫醇和二茂铁衍生物构建的氧化-还原自组装多层膜为模型体系,研究烷基硫醇分子链长对多层膜电化学行为的影响.实验表明,二茂铁基团和电极之间的电子传递反应速率随两者距离的增加呈现指数级下降的趋势;烷基硫醇分子链长对自组装膜电化学行为的影响于不同情况下表现不同.本实验条件下,当多层膜上的电活性基团与电极比较接近时,长链分子自组装膜呈现较强的电化学响应.而当电极与电活性基团之间的距离较远时,短链烷基硫醇分子自组装膜呈现较强的电化学响应. 相似文献
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磷钼杂多酸-L-半胱氨酸自组装超分子膜电极对亚硝酸根电催化还原的研究 总被引:5,自引:0,他引:5
制备了磷钼杂多酸-L-半胱氨酸自组装超分子膜电极(P2Mo18-L-Cys/Au)。采用水平衰减全反射(ATR-FTIR)光谱表征了膜的组成。研究了该膜电极的电化学性质,发现它在1.0 mol/L H2SO4溶液中,于0.0~0.7V(vs.SCE)间CV扫描出现两对稳定、可逆的氧化还原峰,其中峰电位分别为Em1=0.334 V,Em2=0.188V,对应着P2Mo18O_(62)~(6-)的两步2电子-2质子反应;计时库仑法计算了薄膜内的电子传递系数D为5.01 × 10~(-8)cm2·s~(-1)。该膜电极对酸性溶液中的NO_2~-有明显的电催化还原作用,初步探讨了电催化机理。用差分脉冲伏安法(DPV)测定其还原峰电流与NO_2~-的浓度在2.0 ×10~(-6)~2.0 × 10~(-4)mol/L范围内呈良好的线性关系,相关系数为0.9953,检测限5.0×10~(-7)mol/L。该电极用于模拟水样中NO_2~-的测定,结果满意。 相似文献
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硫堇衍生化自组装膜修饰金电极的电化学性质及其对抗坏血… 总被引:3,自引:0,他引:3
将硫堇共价键合到自组装在金电极表面的半胱胺单分子层上,制成了衍生化自组装单分子膜修饰电极,并用电化学方法研究了它的电化学性质,循环伏安图显示其在pH=7.7的磷酸盐缓冲液中,于-0.45~+0.50V(vs.SCE)范围内有2对氧化还原峰,峰电位分别为Epa=214mV,Epc=82mV,E^2pa=-75mV,E^2pc--160mV(vs.SCE),pH在5.0~9.0范围内,峰1有2个质子参 相似文献
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硫醇自组装膜的电化学表观有效厚度 总被引:4,自引:1,他引:3
应 用循 环 伏 安 及 交 流 阻 抗 技 术 研 究 了 18 烷 基 硫 醇 修 饰 的 金 电 极 在 不 同 浓 度 的 K3 Fe( C N) 6/ K4 Fe( C N) 6 溶液中的 电化学 行为,测得 反应的 标准 反应 速率 常数 为~1 0 - 6 c m ·s - 1 ,表观电子 传递系数 为 α= 015 ,β= 022 .提 出自 组装 膜 的电 化学 表 观有 效 厚度 概 念 及计 算 方法 ,应用表观 有效厚 度可以定 量说明自 组装膜 的分子倒 伏或塌 陷的缺陷 程度. 相似文献
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An amperometric chemosensor for the detection of hydrogen peroxide is reported. The sensor is based on 1,4-benzoquinone immobilized on the gold electrode using self-assembled monolayer of short chain symmetrical dithiol as an anchor layer. Sensor analysis was performed by cyclic voltammetry at the potential range from −0.6 V till +0.9 V as well as in the anodic or cathodic potential ranges only. The results indicate oxidative electrochemical decomposition of hydrogen peroxide at the potential of ∼+0.4 V leading to the formation of oxygen while at cathodic potentials a reduction of the formed oxygen as well as of the hydrogen peroxide occur. A decrease in the oxidation potential of hydrogen peroxide on the gold electrode coated by self-assembled monolayer with 1,4-benzoquinone in comparison with that measured on the electrodes coated by the same self-assembled monolayer without 1,4-benzoquinone, indicates electrocatalytic effect of this moiety on oxidative decomposition of hydrogen peroxide. Analytical evaluation of the sensor performance was done in the voltammetric as well as in the chronoamperometric mode. The sensor exhibited linear response over the concentration range till 2.5 mM with a limit of detection ∼4 μM. 相似文献
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Takamasa Sagara Hiroaki Tsuruta Naotoshi Nakashima 《Journal of Electroanalytical Chemistry》2001,500(1-2)
We investigated the effect of the presence of an additive anion while forming a self-assembled monolayer of a thiol-functionalized redox active species upon the behavior in aqueous solutions. A bromide salt was added in an acetonitrile solution of a thiol-functionalized viologen (viologen-thiol: N-pentyl-N′-(11-mercapto)undecyl-4,4′-bipyridinium bishexafluorophosphate) in which the self-assembled monolayer was formed on a polycrystalline Au electrode. We examined the structure and electrochemical behavior of the resulting monolayer-modified electrode in three different aqueous electrolyte solutions. The viologen-thiol monolayer prepared in the presence of Br− exhibited obviously different behavior in both KBr and KF electrolyte solutions from that prepared in the absence of Br−. On the other hand, the difference was minor in KPF6 solution. The difference of the electrochemical behavior was represented by the coverage of the viologen-thiol and the formal potential of viologen dication/radical cation redox couple. The memory that the viologen-thiol monolayer was formed in the presence of Br− was retained in KF and KBr solutions, though it was erased in the electrolyte solution containing PF6−, which is a softer anion than Br−. However, no definitive difference of the film structure was deduced from the electroreflectance study in regard to the monomer content and the average orientation of the viologen moiety. 相似文献
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Zhixian Gao Jie Ren Baoan Ning Huizhong Zhu Yonghong He 《International journal of environmental analytical chemistry》2013,93(8):599-606
Because of their high sensitivity, piezoelectric sensor techniques are extremely useful for environmental or clinical analysis. We developed a piezoelectric crystal DNA biosensor for the detection of the hybridization reaction based on the self-assembled monolayer technology and biotin–avidin system. 3,3′-Dithiopropionic acid was applied to form a self-assembled monolayer (SAM) on the gold surface of the quartz crystal. Avidin was coated on the gold electrode conjugated with 1-ethyl-3-[3-(dimethylamino)propyl]-carbodiimide (EDC) and N-hydroxysuccinimide (NHS), and then biotinylated nucleotide acids were immobilized on the gold electrode surface through the specific interaction of biotin and avidin. Our results indicated that, using this immobilization method, the piezoelectric DNA sensor shows a higher sensitivity and specificity in detecting the hybridization reaction. The sensor can be used repeatedly by electrode regeneration. 相似文献
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利用配对试剂将二茂铁酰胺键合在L-半胱氨酸自组装单层膜(SAM)表面, 制成稳定的二茂铁/L-半胱氨酸修饰电极, 该电极在pH 7.0的磷酸盐缓冲液中有一对很好的氧化还原峰. 运用循环伏安法和交流阻抗谱详细研究了修饰电极的电化学行为, 测得电子转移系数为0.66, 表观电极反应速率常数为6.86 s-1. 该修饰电极对肾上腺素有很好的催化作用, 峰电流与肾上腺素浓度在2.0×10-7~1.0×10-5 mol·dm-3范围内呈现良好的线性关系. 相似文献
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TheElectrochemistryofCytochromecataViologen-thiolSelf-AssembledMonolayerLIJing-hong,CHENGGuang-jin,DONGShao-jun(LaboratoryofE... 相似文献
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The electrochemical behavior of an azobenzene containing self-assembled monolayer (SAM) has been examined by means of in-situ Fourier transform infrared reflection absorption (FTIRRA) spectroscopy. The electrochemical reduction product of azobenzene has been confirmed to be hydrazobenzene. A stable and reversible process in both electrochemistry and architecture has been found in the monolayer film. 相似文献
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Electrocatalytic oxidation and detection of hydrazine in pH 7.0 conditions were studied by using gold electrode modified with self-assembled monolayer (SAM) films of iron phthalocyanine (FePc) complex axially ligated to a preformed 4-mercaptopyridine SAMs. The anodic oxidation of hydrazine in neutral pH conditions with FePc-linked-mercaptopyridine-SAM-modified gold electrode occurred at low overpotential (0.35 V versus Ag|AgCl) and the treatment of the voltammetric data showed that it was a pure diffusion-controlled reaction with the involvement of one electron in the rate-determining step. The mechanism for the interaction of hydrazine with the FePc-SAM is proposed to involve the Fe(III)Pc/Fe(II)Pc redox process. Using cyclic voltammetry (CV) and Osteryoung square wave voltammetry (OSWV), hydrazine was detected over a linear concentration range of 1.3 × 10−5 to 9.2 × 10−5 mol/L with low limits of detection (ca. 5 and 11 μM for OSWV and CV, respectively). At concentrations higher than 1.2 × 10−4 mol/L the anodic peak potential shifted to 0.40 V (versus Ag|AgCl), and this was interpreted to be due to kinetic limitations resulting from the saturation of hydrazine and its oxidation products onto the redox-active monolayer film. This type of metallophthalocyanine-SAM-based electrode is a highly promising electrochemical sensor given its ease of fabrication, good catalytic activity, stability, sensitivity and simplicity. 相似文献
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短杆菌肽在十八烷基硫醇自组装单层膜上的通道行为 总被引:1,自引:0,他引:1
短杆菌肽是短杆芽孢菌在芽孢形成过程中合成的一组憎水十五肽,它能在脂双层膜上形成一价阳离子通道,允许一些一价阳离子通过.短杆菌肽离子通道研究在天然双层膜以及人工双层膜,如类脂双层膜(BLM)、脂质体上开展的较多,而基于支撑膜的研究则极少[1-4].本文在金电极上制备硫醇自组装单层膜,研究了短杆菌肽的离子通道行为,并提出了可能的机理. 相似文献
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Gold electrodes were chemically modified with thioctic acid monolayer designed to mimic biological ion-channel membranes. The technique was then used in the determination of alkali, alkaline earth, thallium(I), and lanthanum metal cations as analytes. Cyclic voltammograms (CV) of [Fe(CN)6]3− an electroactive marker, were measured in the presence of the various types of analyte cations. In the absence of the analyte cation, electrostatic repulsion between the marker anions and the carboxylate groups of the receptor monolayer hindered the approach of the marker anion to the electrode surface and hence hindered its reduction. The modified electrodes responded well to the metal cations except the alkali metal cations. The sensors could detect the trivalent cation La3+ at concentrations as low as 10−8 M. The response of the sensor to the metal cations increase in the order alkali metal3+ can be discriminated in the ratio 1:100. This makes it possible to determine the trivalent ion in a sample matrix containing monovalent and divalent cations. Thallium(I) ion showed marked deviation in its response as compared to monovalent ions of the alkali metals. The ion-channel sensor based on self-assembled monolayer of thioctic acid therefore offers a potential alternative technique for the selective determination of metal ions. 相似文献
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Ming-Hui Yang 《Tetrahedron letters》2005,46(2):349-351
Photochromic aldehyde-substituted spiropyran molecules were incorporated in a self-assembled monolayer structure and the rate of imine formation was determined by the shift in absorbance for the photomerocyanine upon UV irradiation. 相似文献