基于溶胶-凝胶普鲁士蓝膜修饰玻碳电极电催化氧化测定水果中抗坏血酸

制备了一种溶胶-凝胶普鲁士蓝膜修饰玻碳电极,研究了抗坏血酸在该电极上的电催化氧化作用,建立了测定抗坏血酸的方法。在磷酸缓冲溶液(pH 5.0)中,在2.5×10-5-3.2×10-3mol.L-1范围内,抗坏血酸的浓度与氧化峰电流呈线性关系,相关系数为0.999 5,检出限为7×10-6mol.L-1。该修饰电极具有制备简单、灵敏度高、响应速度快、稳定性和重现性好等特点。方法已用于水果中抗坏血酸的测定,所得结果与药典法测得结果一致。     

化学修饰电极的研究 XIII.聚乙烯二茂铁薄膜电极对抗坏血酸的电催化氧化

本文表明用旋转涂层法制备的聚乙烯二茂铁(PVFc)薄膜电极在水溶液和乙腈中, 0.3～1.0V(vs.SCE)电位范围内均可呈现二茂铁(Fe)的氧化还原峰. PVFc薄膜电极对水溶液中的抗坏血酸(AH2)在较宽的pH范围和较宽的浓度范围内均有良好的电催化氧化作用,为EC平行催化过程。利用旋转圆盘电极进行了催化过程动力学分析,求出了催化反应动力学参数.PVFc薄膜电极的稳定性和催化稳定性都较好.在AH~2浓度6x10^-^2～6x10^-^6mol/L范围内,催化峰电流与AH~2浓度呈良好的线性关系,有应用于分析AH~2的意义。     

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。     

基于溶胶-凝胶技术的磷钨杂多酸化学修饰电极的组装及其电催化

将 Dawson型磷钨杂多酸盐 K6 P2 W1 8O6 2 · 1 0 H2 O( P2 W1 8)掺杂到溶胶 -凝胶中 ,滴涂在碳糊电极表面 ,制备成化学修饰电极 .并对该化学修饰电极的电化学行为 ,包括溶液 p H值的影响和电极稳定性等进行了详细的研究 .结果表明 ,此电极既保持了该杂多酸的电化学活性和电催化性能 ,又具有良好的稳定性和灵敏度 .实验发现 ,在 0 .5mol/L H2 SO4溶液中 ,掺杂在溶胶 -凝胶膜中的 P2 W1 8的第 3、第 4个还原峰对 NO- 2 离子具有很好的电催化活性 ,且催化电流同 NO- 2 浓度呈线性关系 .同时 ,P2 W1 8的第 3、第 4个还原峰对分子氧也具有很好的电催化活性 .     

二茂铁衍生物电子传递剂键合的溶胶-凝胶葡萄糖生物传感器

The sol-gel derived glucose biosensor was developed, and the sol-gel membrane was organically modified by N-（3-triethoxysilylpropyl）-ferrocenylmethylamine （FcSi） as sol-gel precursor to make electrochemical biosensor. The structure of biosensor was sol-gel/FcSi＋GOx/GC type （glucose oxidase, GOx）. The ferrocene mediator was chemically immobilized to the silane network, and GOx was entrapped to the sol-gel glass network. Therefore, these structures prevented mediator leakage and retained the enzyme activity. Additionally, pH of electrolyte, temperature effects, and interference of positive substances with biosensor were investigated. And the electrochemical performance of biosensor was studied by amperometry. The results indicated that the linear range, detection limit. and response slope of biosensor was 2.00×10^-4-1.57×10^-3 mol·L^-1, 2.0×10^-4 mol·L^-1 and 5.06×10^5 nA·mol^- 1·L, respectively.     

基于Nafion-L-赖氨酸-溶胶-凝胶膜的电催化型多巴胺传感器

基于Nafion-L-赖氨酸-溶胶-凝胶膜的电催化型多巴胺传感器     

聚萘胺化学修饰电极对抗坏血酸的电催化研究(Ⅰ)

有关苯胺、苯酚类修饰电极前人做了大量工作,而对萘胺类物质的研究则相对较少.本文研究了萘胺聚合膜与过渡金属离子络合特性及其在碱性溶液中的电催化行为,发现聚萘胺薄膜经过渡金属离子处理后对某些氨基酸及抗坏血酸等有机酸的电氧化有催化作用,抗坏血酸浓度1×10~(-6)～1×10~(-4)mol/L范围内与催化电流值呈良好的线性关系.     

聚苯胺薄膜修饰电极对抗坏血酸的电催化氧化

本文表明聚苯胺(PAn)薄膜修饰电极对水溶液中的抗坏血酸(AH_2)在较宽的pH范围和较宽的浓度范围内均有良好的电催化氧化作用, 为EC平行催化过程。利用旋转圆盘电极(RDE)进行了催化过程动力学分析, 求出了催化反应动力学参数。在抗坏血酸浓度10~(-2)～10~(-6) mol·L~(-1)范围内, 催化峰电流与AH_2浓度均成良好的线性关系, 且PAn薄膜修饰电极具有很好的稳定性, 有应用分析抗坏血酸的意义。     

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酸的电催化氧化

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E_pa¹＝214mV。E_pc¹＝82mV,E_pa2＝－75mV,E_pc2＝－160mV(vs.SCE).pH在5.0～9.0范围内,峰1有2个质子参与反应,峰2有1个质子参与反应.它的表面电子转移速率常数k_s＝0.02S^－1.此膜对抗坏血酸的氧化有催化作用,其氧化过电位较在裸金电极上降低了约250mV.催化电流与抗坏血酸的浓度在1.0×10^-6～4.0×10^-3mol/L范围内呈良好的线性关系.抗坏血酸催化氧化的异相速率常数为2.68×10^-3cm/s.     

Fabrication of Poly(allylamine)ferrocene Monolayer Based on Electrostatic Interaction and Its Electrocatalytic Oxidation of Ascorbic Acid

A poly(allylamine)ferrocene monolayer was built on the surface of gold electrode modified with negatively charged alkanethiol based on electrostatic interaction. The electrochemical behavior of the modified electrode was characterized by cyclic voltammetry in detail. The modified electrode was shown to exhibit excellent electrocatalytic response to the oxidation of ascorbic acid. The anodic overpotential was reduced by about 170 mV compared with that obtained at a bare gold electrode. The modified electrode possesses several attractive features, such as simple preparation, fast response and good chemical and mechanical stability.     

Electrocatalytic Oxidation and Determination of Norepinephrine at Poly(Cresol Red) Modified Glassy Carbon Electrode

A glassy carbon electrode (GCE) was modified with electropolymerized films of cresol red in pH 5.6 phosphate buffer solution (PBS) by cyclic voltammetry (CV). The modified electrode shows an excellent electrocatalytic effect on the oxidation of norepinephrine (NE). The peak current increases linearly with the concentration of NE in the range of 3×10^?6–3×10^?5 M by the differential pulse voltammetry. The detection limit was 2×10^?7 M. The modified electrode can also separate the electrochemical responses of norepinephrine and ascorbic acid (AA). The separation between the anodic peak potentials of NE and AA was 190 mV by the cyclic voltammetry. And the responses to NE and AA at the modified electrode were relatively independent.     

Electrochemical Preparation of Poly(Malachite Green) Film Modified Nafion‐Coated Glassy Carbon Electrode and Its Electrocatalytic Behavior Towards NADH,Dopamine and Ascorbic Acid

Poly(malachite green) film modified Nafion‐coated glassy carbon electrodes have been prepared by potentiodynamic cycling in malachite green solution. The pH of polymerisation solution has only minor effect on film formation. Electrochemical quartz crystal microbalance (EQCM) was used to monitor the growth of the poly(malachite green) film. Cyclic voltammogram of the poly(malachite green) film shows a redox couple with well‐defined peaks. The redox response of the modified electrode was found to be depending on the pH of the contacting solution. The peak potentials were shifted to a less positive region with increasing pH and the dependence of the peak potential was found to be 56 mV per pH unit. The electrocatalytic behavior of poly(malachite green) film modified Nafion‐coated glassy carbon electrodes was tested towards oxidation of NADH, dopamine, and ascorbic acid. The oxidation of dopamine and ascorbic acid occurred at less positive potential on poly(malachite green) film compared to bare glassy carbon electrode. In the case of NADH, the overpotential was reduced substantially on modified electrode. Finally, the feasibility of utilizing poly(malachite green) film electrode in analytical estimation of ascorbic acid was demonstrated in flow injection analysis.     

Electrocatalytic Oxidation of Hydrazine at the Poly(Glutamic Acid) Chemically Modified Electrode and Its Amperometric Determination

ABSTRACT

The electrochemical polymerization of glutamic acid at the glassy carbon electrode was investigated in phosphate buffer solution by cyclic voltammetry. The applied voltage range, pH of electrolyte, cyclic number were explored for optimal polymerization conditions. The resulting film exhibits an electrocatalytic ability to hydrazine, reducing the overpotential by 500mV. The electrocatalytic response of hydrazine is evaluated with regard to pH, scan rate, applied voltage, hydrazine concentration and other variables. The rate constant of the catalytic reaction was 1.2 × 10⁴ M^?1.s^?1. When used as amperometric detector, the modified electrode yields a detection limit of 1 × 10^?8 M hydrazine. The electrode is rather stable even after use for a month and a reproducible response was obtained.     

Electropreparation of Poly(benzophenone‐4) Film Modified Electrode and Its Electrocatalytic Behavior Towards Dopamine,Ascorbic Acid and Nitrite

The oxidation of benzophenone‐4 (2‐hydroxy‐4‐methoxybenzophenone‐5‐sulfonic acid) at glassy carbon electrode gives rise to stable redox active electropolymerized film during repetitive potential cycling between 0 to 1.3 V (Ag/AgCl). Cyclic voltammogram of poly(benzophenone‐4) film shows a redox couple with well‐defined peaks. The redox response of the modified electrode was found to be depending on the pH of the contacting solution. The peak potentials were shifted to a less positive region with increasing pH and the dependence of the peak potential was found to be 51 mV/pH. The electrocatalytic behavior of poly(benzophenone‐4) film modified electrode towards oxidation of dopamine, ascorbic acid and reduction of nitrite was investigated. The oxidation of dopamine and ascorbic acid occurred at less positive potential on poly(benzophenone‐4) film compared to bare glassy carbon electrode. For dopamine, the overpotential was reduced about 180 mV. Feasibility of utilizing poly(benzophenone‐4) film coated electrode in analytical estimation of dopamine, ascorbic acid and nitrite was also demonstrated.     

铁氰化镍修饰电极对抗坏血酸电催化氧化的研究

抗坏血酸(AH_2)在玻碳和铂电极上的过电位较大,其电极反应不可逆.有关AH_2在碳及其它修饰电极上的电催化氧化已有一些报道,如减压热处理、Al_2O_3微粒研磨、普鲁士蓝修饰膜和聚乙烯二茂铁修饰膜等.本文研究了铁氰化镍修饰膜电极催化AH_2氧化的电化学行为.发现其阳极峰电流与AH_2浓度呈线性关系,可测定1×10~(-7)mol/L的AH_2,其灵敏度比聚乙烯二茂铁修饰电极提高一个数量级.用于蔬菜、水果中AH_2的测定,结果满意.     

Electrocatalytic Determination of Ascorbic Acid Using a Palladium Coated Nanoporous Gold Film Electrode

Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behavior of ascorbic acid (AA) on palladium coated nanoporous gold film (PdNPGF) electrode. The deposition of palladium was done through oxidation of copper UPD layer by palladium ions. This low Pd‐loading electrode behaved as the nanostructured Pd for electrocatalytic reaction. The PdNPGF electrode exhibits excellent electrocatalytic behavior by enhancing the AA oxidation peak current due to synergistic influence of the Pd film and NPGF. The kinetic parameters such as electron transfer coefficient, α, was 0.47 and the voltammetric responses of the PdNPGF electrode were linear against concentration of AA in the ranges of 2.50–33.75 mM and 0.10–0.50 mM with CV and DPV respectively.     

阿魏酸聚合修饰玻碳电极的制备及其对NADH的催化氧化

研究了阿魏酸修饰电极的制备、性质及对NADH的电催化作用.该电极在0.1mol/L磷酸缓冲溶液(pH=6.60)中,于-0.1～+0.50V(vs.Ag/AgCl)电位范围内呈现一对氧化还原峰,其式量电位E₀为+0.188V(vs.Ag/AgCl),且E₀随pH增加而负向移动.电子转移系数为0.496,表观电极反应速率常数(ks)为6.6s^-1.电极反应的电子数为1且有1个质子参与.该修饰电极对NADH氧化具有很好的催化作用.在NADH存在下,电极过程由扩散控制,扩散系数为1.76×10^-6cm²/s.NADH浓度在0.01～5.0mmol/L范围内与峰电流呈现良好的线性关系.通过计时安培法测得催化速率常数为6.82×10³mol^-1·L·s^-1.