二茂铁硫醇自组装膜的电化学行为及其离子对效应

详细了研究１０－二基铁－１－癸硫醇（ＨＳＣ１０Ｆｃ）在金基底上形成的自组装单分子膜的电化学行为,发现ＨＳＣ１０Ｆｃ在金基底上形成稳定的自组装膜,并且在０．１ｍｏｌ／Ｌ的ＨＣｌＯ４溶液中表现出可逆的氧化还原行为,但其氧化还原峰的峰形和峰位极易溶液中阴离子种类和浓度的影响,考察了二茂铁自组装膜及通过后置换形成的二茂铁硫醇／十二烷基硫醇混合膜在混合电解液中的电化学行为,直接比较了两种不同阴离子与二茂铁阳     

纳米银掺杂炭气凝胶修饰电极对卤素离子的电化学响应

首次以新型的纳米银掺杂炭气凝胶为材料,制备了一种新型纳米银炭电极,并考察了该电极对卤素离子的电化学响应。在0.1 mol/L的KNO3中,用微分脉冲伏安法对含Cl-的溶液以及卤素离子共存时的溶液进行测定,结果表明:峰电流与Cl-浓度呈线性关系,线性范围为2.0×10-7-4.2×10-5mol/L;检出限为1.2×10-8mol/L。此外响应电流与Cl-、Br-、I-3种离子的总浓度在6.0×10-7-1.2×10-5mol/L范围内呈线性关系。结果表明,纳米银掺杂炭气凝胶修饰电极可望用于痕量卤素离子的测定。     

致密二茂铁硫醇自组装膜的电化学行为

合成了11-二茂铁基十一烷基-1-硫醇(HS-(CH₂)₁₁-Fc)，利用自组装膜的特点，通过分子设计将二茂铁基团引入到自组装膜中。在金电极表面构筑有序单分子膜，制备出具有电化学活性的修饰层，研究其电化学行为，作为考察复杂电化学动力学的理想模型。进一步探究其电子传递的特点与自组装膜表面覆盖度之间的联系，提出了一种新的电子传递模型，研究电子转移与膜结构的对应关系，为更深层次的分子设计和功能组装提供理论指导。     

膜电阻对自组装膜修饰电极电化学行为的影响

应用循环伏安和交流阻抗技术研究了 16烷基硫醇自组装膜修饰的金电极在Fe(CN) 63 - /Fe(CN) 64 - 溶液中的电化学行为 .无“针孔”缺陷的自组装膜对溶液与基底间的界面电子转移具有强烈的阻碍作用 ,当过电位较大时 ,In(I/ η)对 η1/2 之间具有良好的线性关系 .通过对Au/SAM /Hg模拟体系的电流———电压曲线进行测定 ,得到了自组装膜膜电阻的特征 .指出由于膜电阻的存在 ,自组装膜修饰电极在Fe(CN) 63 - /Fe(CN) 64 - 溶液中的行为实质上反映了膜自身的电阻特征     

纳米银/半胱氨酸修饰金电极的制备及对苯二酚的测定

纳米银/半胱氨酸修饰金电极的制备及对苯二酚的测定;纳米银;L-半胱氨酸;自组装金电极;对苯二酚     

辅酶Q在CPT自组装修饰电极上的电化学行为及其分析应用

采用自组装方法制备了卡托普利(CPT)修饰电化学传感器,并对其在金电极表面形成的单分子膜进行了表征。循环伏安试验结果表明,辅酶Q在CPT修饰电极上能发生准可逆的电化学反应。该传感器对辅酶Q测定具有良好的响应,测定范围为5.0×10-6~6.0×10-5mol.L-1,检出限为2.0×10-6mol.L-1,异相电子传递速率常数ks为5.4×10-3cm.s-1。对CPT修饰膜的稳定性进行考察,讨论辅酶Q发生电化学反应的异相电子传递速率常数ks及其影响机制。     

铜卟啉-L-半胱氨酸自组装复合膜修饰电极的制备及电化学性能研究

利用电化学扫描法在L 半胱氨酸(Cys)自组装单分子膜修饰金电极表面现场制备了金属卟啉复合膜,对其进行SEM和ATR FTIR表征。修饰电极的支持电解质以及pH值对膜的稳定性和灵敏度有很大影响。铜卟啉 L Cys膜对H2O2具有良好的电催化还原特性,催化电流与H2O2浓度在1 0×10 6到3 0×10 5mol·L 1范围内线性关系,相关系数0 9995,检测限达1 0×10 7mol·L 1。     

用超微电极研究二茂铁等物质在聚电解质聚乙二醇.高氯酸锂中的伏安行为

用超微电极研究了聚电解质聚乙二醇；高氯酸锂的电化学性能。用伏安法研究了气体，有机小分子，温度，支持电解质，聚合链长的影响。结果表明，有机小分子有增塑效应，物质的扩散速率随温度的上升而增加，随支持电解质中阳离子半径增大而增加，随聚合物链长增加页减小。     

二茂铁基嵌段共聚物制备及自组装研究

本文综述了近年来二茂铁基嵌段共聚物制备及自组装的研究进展.对环状二茂铁单体的活性阴离子引发开环聚合(ROP)、过渡金属催化开环聚合(ROP)及聚合机理和聚合物自组装胶束的结构、表征和潜在应用作了介绍.     

4-巯基吡啶自组装修饰金电极的电化学性质及对抗坏血酸的测定

研究了 4 巯基吡啶自组装膜 (SAM)修饰金电极的制备及其电化学性质 ,并用于抗坏血酸 (AA)的测定。在pH 3.0盐酸 邻苯二甲酸氢钾缓冲溶液中 ,AA在SAM修饰金电极上产生一灵敏的氧化峰 ,峰电流与AA浓度在 4 .0× 10 - 6 ～ 1.0× 10 - 3mol L范围内呈良好的线性关系 ,检出限为 2 .7× 10 - 6 mol L ,相关系数为0 9978。该电极对多巴胺 (DA)有排斥作用 ,重现性良好 ,可用于AA的灵敏测定。     

Hydrogen peroxide sensor based on horseradish peroxidase immobilized on a silver nanoparticles/cysteamine/gold electrode

A third-generation hydrogen peroxide biosensor was prepared by immobilizing horseradish peroxidase (HRP) on a gold electrode modified with silver nanoparticles. A freshly-cleaned gold electrode was first immersed in a cysteamine–ethanol solution, and then silver nanoparticles were immobilized on the cysteamine monolayer, and finally HRP was adsorbed onto the surfaces of the silver nanoparticles. This self-assemble process was examined via atomic force microscopy (AFM). The immobilized horseradish peroxidase exhibited an excellent electrocatalytic response toward the reduction of hydrogen peroxide. The linear range of the biosensor was 3.3 M to 9.4 mM, and the detection limit was estimated to be 0.78 M. Moreover, the biosensor exhibited a fast response, high sensitivity, good reproducibility, and long-term stability.     

银纳米修饰电极的制备及其对灿烂甲酚蓝的催化研究

用共价修饰法制备了银纳米修饰电极,通过透射电子显微镜(TEM)、紫外可见光谱和电化学交流阻抗谱进行了表征和研究。实验表明,该修饰电极对灿烂甲酚蓝(BCB)的电化学氧化还原有较强的催化作用,氧化峰电流与其浓度在4.0×10-7～2.1×10-4mol L范围内成线性关系,相关系数为0.9989,检出限为1.5×10-8mol L。     

芦丁在纳米金修饰玻碳电极上的电化学行为及其测定

采用循环伏安法将纳米金电沉积于玻碳电极表面,制备了纳米金修饰玻碳电极(NG/GCE).在pH3.29的Britton-Robinson(B-R)缓冲溶液中,用循环伏安法研究了芦丁在NG/GCE上的电化学行为.结果表明,NG/GCE对芦丁的氧化还原反应有良好的电催化作用.用方波伏安法测得芦丁的还原峰电流与其浓度在2.0×10-8～2.0×10-6mol/L范围内呈线性关系,检出限为1.0×10-8mol/L(S/N=3).     

多贝斯在纳米金修饰玻碳电极上的电化学行为与测定

采用循环伏安法将纳米金电沉积于玻碳电极表面,制备了纳米金修饰玻碳电极(NG/GCE).在0.05 mol/L H2SO4溶液中,用循环伏安法研究了多贝斯在NG/GCE上的电化学行为.结果表明,NG/GCE对多贝斯的氧化还原反应有明显的电催化作用.建立了测定多贝斯的新方法,用方波伏安法测得多贝斯的氧化峰电流与其浓度在4....     

A novel nonenzymatic hydrogen peroxide sensor based on multi-wall carbon nanotube/silver nanoparticle nanohybrids modified gold electrode

A novel strategy to fabricate hydrogen peroxide (H₂O₂) sensor was developed based on multi-wall carbon nanotube/silver nanoparticle nanohybrids (MWCNT/Ag nanohybrids) modified gold electrode. The process to synthesize MWCNT/Ag nanohybrids was facile and efficient. In the presence of carboxyl groups functionalized multi-wall carbon nanotubes (MWCNTs), silver nanoparticles (Ag NPs) were in situ generated from AgNO₃ aqueous solution and readily attached to the MWCNTs convex surfaces at room temperature, without any additional reducing reagent or irradiation treatment. The formation of MWCNT/Ag nanohybrids product was observed by transmission electron microscope (TEM), and the electrochemical properties of MWCNT/Ag nanohybrids modified gold electrode were characterized by electrochemical measurements. The results showed that this sensor had a favorable catalytic ability for the reduction of H₂O₂. The resulted sensor could detect H₂O₂ in a linear range of 0.05-17 mM with a detection limit of 5 × 10⁻⁷ M at a signal-to-noise ratio of 3. The sensitivity was calculated as 1.42 μA/mM at a potential of −0.2 V. Additionally, it exhibited good reproducibility, long-term stability and negligible interference of ascorbic acid (AA), uric acid (UA), and acetaminophen (AP).     

Determination of benorilate in pharmaceutical formulations and its metabolite in urine at carbon paste electrode modified by silver nanoparticles

Benorilate was determined by the differential pulse voltammetry (DPV) using a carbon paste electrode modified by silver nanoparticles in 1.25 × 10⁻³ mol l⁻¹ KH₂PO₄ and Na₂HPO₄ buffer solution (pH = 6.88, 25 °C) .The anodic peak potential was +0.970 V (versus SCE). A good linear relationship was realized between the anodic peak currents and benorilate concentrations in the range of 1.0 × 10⁻⁷ to 2.5 × 10⁻⁴ mol l⁻¹ with the detection limit of 1.0 × 10⁻⁸ mol l⁻¹. The recovery was 95.2-103.6% with the relative standard deviation of 3.6% (n = 9). The pharmaceutical preparations, benorilate tablets samples and its metabolite (salicylic acid) in urine were determined with the desirable results.     

辣根过氧化酶在磁性纳米修饰的离子注入电极上的电化学和电催化行为

辣根过氧化酶(HRP)在Co/NH2/ITO离子注入电极上有一对良好的氧化还原峰,峰电位分别为Epc=-0.2 V,Epa=-0.01 V(vsAg/AgCl)。该修饰电极对H2O2具有催化作用,可以用作H2O2的生物传感器,峰电流与H2O2的浓度分别在1.0×10-10~2.0×10-8mol/L和2.0×10-8~1.0×10-7mol/L范围内呈线性关系,线性回归方程分别为Ip(mA)=2.2986+0.06632c(nmol/L)和Ip(mA)=3.5788+7.3053E-4c(nmol/L),相关系数分别为0.9972和0.9688。检出限为1.0×10-10mol/L。     

Preparation of a carbon ceramic electrode modified by 4-(2-pyridylazo)-resorcinol for determination of trace amounts of silver

A 4-(2-pyridylazo)-resorcinol (PAR)-modified carbon ceramic electrode (CCE) prepared by the sol-gel technique has been reported for the first time in this paper. By immersing the CCE in aqueous solution of PAR (0.001 mol L⁻¹), after a short period of time, a thin film of PAR was rapidly formed on the surface of the electrode due to its strong adsorption properties. A differential pulse anodic stripping voltammetric (DPASV) method was developed for determination of Ag(I) at the modified carbon ceramic electrode. The analysis procedure consisted of an open circuit accumulation step in a sample solution which was continuously stirred for 12 min. This was followed by replacing the medium with a clean solution where the accumulated Ag(I) was reduced for 15 s in −0.6 V. Then, the potential was scanned from −0.2 to +0.2 V to obtain the voltammetric peak. The detection limit of silver(I) was 0.123 μg L⁻¹, and for seven successive determinations of 10, 100 and 200 μg L⁻¹ Ag(I), the relative standard deviations were 2.1, 1.4 and 1.03%, respectively. The calibration curve was linear for 0.5-300 μg L⁻¹ silver(I). The procedure was applied to determine silver(I) in X-ray photographic films and super-alloy samples.     

Comparative antibacterial potential of silver nanoparticles prepared via chemical and biological synthesis

New and improved approaches are urgently needed to fight the increasing number of multi-drug resistant bacteria. The antibacterial effect of silver nanoparticles (AgNPs) prepared by standardized chemical and biological syntheses is compered here. Biological systems included extracts of Opuntia ficus-indica mucilage and extracellular growth broth of Aspergillus niger and Bacillus megaterium. The nanoparticles were characterized by infrared spectroscopy, IR, and transmission electron microscopy. All of the AgNPs shared characteristic IR peaks and had an average size of 20–60 nm. The AgNPs were mainly spherical regardless of synthetic path. The synthesis based on the extracellular broth of the fungus, due to the highest biomass and active compounds concentration, resulted in a high yield of nanoparticle formation. These AgNPs also exhibited the highest inhibition zone against Salmonella typhimurium and Staphylococcus aureus. The syntheses reported here have no significant influence on AgNPs physical characteristics, as compared to literature, but represent processes with shorter reaction time. Additionally, the fungal based nanoparticles have superior antibacterial characteristics.     

Preparation of silver nanoparticles in liquid crystalline systems

Silver nanoparticles preparation and the aggregation stability of the particles was investigated in lamellar liquid crystalline systems. A liquid crystal of HDTABr/pentanol/water was first prepared. The water content was next increased while keeping the mass ratio of HDTABr and pentanol constant. Silver nanoparticles were produced by replacing the aqueous phase by Ag sols of various concentrations (0.5–5×10^–3 mol/l) or by an in situ preparation method, i.e., interlamellar reduction of Ag⁺ ions in the liquid crystalline phase. The stability of the silver nanoparticles was monitored by UV-VIS spectroscopy and TEM. The particle size ranged from 5 to 44 nm. The kinetic of silver nanoparticle aggregation was investigated. The effect of nanoparticles on structural ordering in liquid crystals was studied by XRD measurements and it was established that the lamellar distance (d_L) was only slightly altered. Electronic Publication