磺胺在碳纳米管修饰玻碳电极上的电化学行为

磺胺类抗菌药是一类允许在饲料中添加的兽用广谱抗菌药.它被广泛用于治疗家畜呼吸道、消化道细菌感染、猪萎缩性鼻炎、禽霍乱、伤寒等疾病[1].停药期用药或用药不当将导致动物食品中抗菌药残留超标.人们长期食用含磺胺类抗菌药残留超标的动物产品,将导致肝肾损伤和体内耐药菌株产生,危害到人们的身体健康和疾病治疗.     

Electrocatalytic oxidation of hydrazine at a glassy carbon electrode modified with nickel ferrite and multi-walled carbon nanotubes

A hydrothermal technique was used to synthesize nickel ferrite nanoparticles (NF-NPs) deposited on multi-walled carbon nanotubes (MWCNTs). The material was characterized by scanning electron microscopy, energy dispersive spectrometry, and X-ray powder diffraction which showed that the NF-NPs are located on the surface of the carboxylated MWCNTs. The material was used to modify a glassy carbon electrode which then was characterized via cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry. The electrode displays strong electrochemical response to hydrazine. A potential hydrazine sensing scheme is suggested.

Electrocatalytic oxidation of nitric oxide at nano-TiO2/Nafion composite film modified glassy carbon electrode

A novel nanocrystalline TiO₂ (nano-TiO₂) and Nafion composite film modified glassy carbon electrode has been developed for the determination of nitric oxide (NO) radical in an aqueous solution. This modified electrode can be employed as a NO sensor with a low detection limit, fast response, high sensitivity and selectivity. Two apparent anodic peaks were observed at 0.67 and 0.95 V at the nano-TiO₂ modified glassy carbon electrode by differential pulse voltammetry (DPV). After further modification with a thin film of Nafion, which was capable of preventing some anionic interference such as nitrite and ascorbic acid, only one peak appeared and the peak current enhanced greatly. The chronocoulometric experimental results showed NO was oxidized by one-electron transfer reaction at the composite film modified electrode. The amperometric responses increased linearly with the concentrations of NO ranging from 3.6×10⁻⁷ mol/L to 5.4×10⁻⁵ mol/L. The detection limit was estimated to be 5.4×10⁻⁸ mol/L. In this sensor system, the modification film provides complete selectivity for NO over nitrite anions (NO₂⁻).     

Electrocatalytic oxidation of the reduced nicotinamide adenine dinucleotide at carbon ionic liquid electrode modified with polythionine/multi-walled carbon nanotubes composite

A carbon ionic liquid electrode (CILE) was modified with a polythionine (PTh)/multi-walled carbon nanotubes (MWCNTs) composite and used for the detection of reduced nicotinamide adenine dinucleotide (NADH). The electrode was prepared by electrochemical polymerization of thionine on the MWCNTs in neutral medium. Cyclic voltammetry indicated that the electrode was capable of mediating the oxidation of NADH at an overpotential as low as 0.03 V. Amperometric experiments showed that a sensitive and stable response towards NADH is obtained within 5 s. The linear range for the determination of NADH is from 0.8 μmol L^?1 to 422 μmol L^?1, with a detection limit of 0.26 μmol L^?1 (S/N = 3). The wide linear range, lower detection limit and faster response towards NADH suggests that the new method potentially is useful for developing NAD⁺-dependent enzyme-based biosensors.     

Voltammetric oxidation and determination of cinnarizine at glassy carbon electrode modified with multi-walled carbon nanotubes

We discovered a novel method to prepare a protein-based hydrogel, that is, a “Three-Dimensional Nanostructured Protein Hydrogel (3D NPH)”, which is composed of protein–polymer hybrid nanoparticles. In this study, we propose a novel protein microarray whose 3D NPH spots were prepared by dispensing a small volume of the solution of protein–polymer mixture on a substrate. The dispensed solution had a short time for cross-linking before its drying-up and the resulting 3D NPH had loosely cross-linked, thin spongy structure. Therefore, the reaction ratio between ligands and analytes was drastically improved in this system compared with the large volume system for Surface Plasmon Resonance (SPR) protein microarray.     

苦参碱在多壁碳纳米管修饰玻碳电极上的电催化氧化及其电分析方法

研究了苦参碱(Matrine, MT) 在多壁碳纳米管修饰玻碳电极(MWCNT/GCE)上的电化学行为. 与GCE相比, MT在MWCNT/GCE上峰电位负移120 mV, 峰电流增大约2.5倍, 表明MWCNT/GCE对MT的电化学氧化具有良好的催化作用. 同时测定并计算了MT在MWCNT/GCE上的电极过程动力学参数: 电子转移系数α、电极反应速率常数ks、扩散系数D. 运用差分脉冲伏安法对苦参碱样品含量进行测定, 相对标准偏差为0.12%～2.9%, 加标回收率为98.4%～99.0%. 该方法可用于MT的电化学定量测定.     

二苯氨基碳酰肼在多壁碳纳米管修饰电极上的电催化氧化及电化学动力学研究

肼及其衍生物被广泛应用于医药,农药,水处理,军事,航天,光稳定剂以及化工生产助剂等诸多领域。因此对肼及其衍生物的研究有着极其重要的意义。二苯氨基碳酰肼(二苯氨基脲,又名二苯卡巴肼,D iphenyl Carbazide,DPC)广泛用于重金属离子的检测分析[1-4]。但是,目前关于DPC的电化学     

Electrocatalytic oxidation of ethylene glycol on Pt and Pt-Ru nanoparticles modified multi-walled carbon nanotubes

The synthesis and characterization of catalysts based on nanomaterials, supported on multi-walled carbon nanotubes (CNT) for ethylene glycol (EG) oxidation is investigated. Platinum (Pt) and platinum-ruthenium (Pt-Ru) nanoparticles are deposited on surface-oxidized multi-walled carbon nanotubes [Pt/CNT; Pt-Ru/CNT] by the aqueous solution reduction of the corresponding metal salts with glycerol. The electrocatalytic properties of the modified electrodes for oxidation of ethylene glycol in acidic solution have been studied by cyclic voltammetry (CV), and excellent activity is observed. This may be attributed to the small particle size of the metal nanoparticles, the efficacy of carbon nanotubes acting as good catalyst support and uniform dispersion of nanoparticles on CNT surfaces. The nature of the resulting nanoparticles decorated multiwalled carbon nanotubes are characterized by scanning electron microscopy (SEM) and transmission electron microscopic (TEM) analysis. The cyclic voltammetry response indicates that Pt-Ru/CNT catalyst displays a higher performance than Pt/CNT, which may be due to the efficiency of the nature of Ru species in Pt-Ru systems. The fabricated Pt and Pt-Ru nanoparticles decorated CNT electrodes shows better catalytic performance towards ethylene glycol oxidation than the corresponding nanoparticles decorated carbon electrodes, demonstrating that it is more promising for use in fuel cells.     

Application of multi-walled carbon nanotubes modified carbon ionic liquid electrode for electrocatalytic oxidation of dopamine

A simple, sensitive, and reliable method based on a multi-walled carbon nanotubes (MWNTs) modified carbon ionic liquid electrode (CILE) has been successfully developed for determination of dopamine (DA) in the presence of ascorbic acid (AA). The acid-treated MWNTs with carboxylic acid functional groups could promote the electron-transfer reaction of DA and inhibit the voltammetric response of AA. Due to the good performance of the ionic liquid, the electrochemical response of DA on the MWNTs/CILE was better than that of other MWNTs modified electrodes. Under the optimum conditions a linear calibration plot was obtained in the range 5.0×10(-8) to 2.0×10(-4) mol L(-1) and the detection limit was 1.0×10(-8) mol L(-1).     

苯甲酰肼在多壁碳纳米管修饰玻碳电极上的电催化氧化及其电化学动力学性质

研究了苯甲酰肼(BH)在MWCNT/GCE上的电化学行为。实验结果表明,BH在GCE上的直接电化学氧化十分迟缓,无氧化峰出现,但在MWCNT/GCE上BH在0.20 V处出现了一个不可逆氧化峰,且峰电流大幅度增大,表明MWCNT/GCE对BH电化学氧化具有良好的催化作用。同时用计时库仑法(Chro-nocoulometry,CC)和计时电流法(Chronoamperometry,CA)测定了电极过程动力学参数:扩散系数D=8.73×10-5cm2.s-1,电子转移系数α=0.85,电极反应速率常数kf=1.45×10-3s-1。稳态电流-时间实验结果表明,电流响应信号随其浓度成比例增长,响应时间小于6 s,最低响应浓度为1×10-6mol/L。该方法可用于BH电化学定量测定。     

Electrocatalytic oxidation of glucose at a Ni-curcumin modified glassy carbon electrode

The electrocatalytic oxidation of glucose was investigated on a nickel-basedchemically modified electrode (Ni(II)-curcumin) prepared by electropolymerization of Ni-curcumin complex (curcumin=1,7-bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione) in alkaline solution. Reaction kinetic and mechanism were investigated by using cyclic voltammetry (CV) and chronoamperometry (CA) techniques and steady-state polarization measurements. Cyclic voltammetry studies indicated that in the presence of glucose the anodic peak current of surface redox mediator was increased, followed by decrease in the corresponding cathodic current. This indicates that glucose was oxidized at the surface of this modified electrode. The results were explained based on the concept of electrocatalytic reactions that occur in this chemically modified electrode. The diffusion coefficient of glucose and the rate constant of the catalytic oxidation of glucose were found to be 6.7×10⁻⁶ cm² s⁻¹ and 6.5×10³ M⁻¹ s⁻¹, respectively. It has shown that by using the Ni-curcumin modified electrode, glucose can be determined with good response and low detection limit.     

百里香酚在聚甲苯胺蓝/多壁碳纳米管修饰电极上的电催化氧化动力学研究

采用电聚合、滴涂及多层修饰方法制备了4种修饰电极,百里香酚在几种修饰电极上均是不可逆电氧化反应,其中聚甲苯胺蓝/多壁碳纳米管修饰电极的电催化效果最佳,过电位降低了111mV,氧化峰电流增大了5倍。在pH为7.69的PBS溶液中,百里香酚在聚甲苯胺蓝/多壁碳纳米管修饰电极上是电子转移数和质子数均为1的扩散控制不可逆电氧化过程,扩散系数D=4.8470×10-4cm2/s,电极有效面积A=0.0383cm2。氧化峰电流ip与浓度c在9.0×10-6～5.0×10-4mol/L范围内呈良好的线性关系:ip(A)=-3.781×10-5-0.0491c(mol/L),相关系数R=-0.9958,样品测定回收率为96.88%～101.50%。     

Electrochemical oxidation of sulfur-containing amino acids on an electrode modified with multi-walled carbon nanotubes

MWNT-modified electrodes are introduced for the voltammetric determination of sulfur-containing amino acids. The morphology of the electrode surface has been characterized by atomic force microscopy. The MWNT layer consists of deeply intertwined vermicular structures with the average diameter of 25 nm. Cysteine, glutathione and methionine are oxidized on the electrode while only cysteine gives signals on the glassy carbon (GC) electrode. The application of such electrodes leads to a decreased overpotential and increase of oxidation currents for cysteine in comparison with a bare GC electrode. The schemes of oxidation are proposed. A decrease of the lower limit of determination and an enlargement of the analytical range for antioxidants were obtained. A simple, fast and accurate procedure for the voltammetric determination of methionine in pharmaceuticals has been developed and can be recommended for quality control purposes.     

Electrocatalytic oxidation of hydrogen peroxide and cysteine at a glassy carbon electrode modified with platinum nanoparticle-deposited carbon nanotubes.

A glassy carbon electrode modified with platinum nanoparticle-decorated carbon nanotubes (Pt-CNT/GCE) was prepared. The electrochemical behaviors for the catalysis oxidations of hydrogen peroxide and cysteine were studied. The Pt-CNT/GCE showed catalytic activity for electro-oxidation of hydrogen peroxide at 0.6 V in PBS (pH = 7.0) and for that of cysteine at 0.55 V in sulfuric acid medium (pH 相似文献   

一氧化氮在肌红蛋白修饰电极上的电催化还原

本文研究了醋酸盐缓冲体系中NO2^-歧化产物NO在肌红蛋白修饰玻碳电极上的电催化还原反应, 其还原峰电位为-0.68V(vs. SCE)。文中考察了溶液酸度、亚硝酸根离子浓度等对修饰电极的电化学行为的影响, 并对一氧化氮在肌红蛋白修饰电极上的电催化还原机理进行了探讨。     

Electrocatalytic oxidation of glucose in a neutral medium on an electrode modified by carboxylated multi-walled carbon nanotubes and by silver and palladium

Russian Chemical Bulletin - Drop deposition of a carboxylated multi-walled carbon nanotube suspension and layer-by-layer electrochemical deposition of silver and palladium were used to modify...     

Electrocatalytic oxidation of NADH based on polyluminol and functionalized multi-walled carbon nanotubes

This work presents that the electrocatalytic oxidation of NADH can be enhanced by the hybrid composites of polyluminol and functionalized multi-walled carbon nanotubes (MWCNTs). The hybrid composites can be easily prepared by the electropolymerization of luminol and the adsorption of functionalized MWCNTs. The modified electrode exhibits two redox couples which can show two electrocatalytic peaks at about 0.1 and 0.3 V (vs. Ag/AgCl) to NADH oxidation. The kinetic constant, k(kin), for the electrocatalytic oxidation of NADH, evaluated by chronoamperometry and voltammetry using a rotating disk electrode (RDE), provided values close to 10(5) M(-1) s(-1). At an applied potential of 0.1 V, the sensor provides a linear response range for NADH from 5 × 10(-6) up to 1.5 × 10(-4) M with a sensitivity of 183.9 μA mM(-1) cm(-2), and detection and quantification limits of 0.6 and 5 μM (S/N = 3), respectively.     

盐酸左氧氟沙星在聚L-精氨酸/多壁碳纳米管修饰电极上的电化学行为

运用循环伏安法、线性扫描伏安法、计时电量法等研究了盐酸左氧氟沙星在聚L-精氨酸/多壁碳纳米管修饰电极上的电化学行为。实验表明:盐酸左氧氟沙星在聚L-精氨酸/多壁碳纳米管修饰电极上的电极反应过程为等电子等质子吸附控制的不可逆过程,在pH=6.0的Na2HPO4-NaH2PO4支持电解质中,其氧化峰电流与浓度在7.0×10-6~1.0×10-4mol·L-1范围内呈良好的线性关系,相关系数R为-0.9992,检出限为5.0×10-6mol·L-1,样品测定回收率为98.26%~101.70%。     

溶胶-凝胶-钴-邻菲啰啉修饰电极对一氧化氮的电催化氧化及其测定

报道了溶胶 凝胶 钴 邻菲口罗啉膜修饰电极的制备方法及其在一氧化氮(NO)检测中的应用,采用循环伏安法(CV)研究修饰电极的电化学特性,差示脉冲伏安法(DPV)对NO进行检测。该修饰电极对NO的电化学氧化具有很好的催化作用,使其氧化电位负移了210mV,氧化峰电流与NO浓度在5.6×10-8～2.8×10-5mol/L范围内呈良好的线性关系,相关系数r=0.999,检测限为1.4×10-8mol/L,且生物体内常见的干扰物质如抗坏血酸、NO2-和儿茶酚胺类神经递质的代谢物等不干扰测定。