固体六氯合铁酸钴微粒在聚电解质中的现场显微红外光谱电化学

报道了六氰合铁酸钴（ＣｏＨＣＦ）微粒在聚电解质中的光谱电化学及电催化行为，ＣｏＨＣＦ的循环伏安呈现一对可逆氧化还原峰，电位扫速在１００ｍＶ／ｓ范围内，峰电流与扫速成正比，现场红外光谱表明，氧化还原属于ＣｏＨＣＦ中的Ｆｅ（Ⅱ／Ⅲ）的转化，ＣｏＨＣＦ微粒可以催化抗坏血酸的氧化，使氧化电位负移，氧化电流增大，根据现场红外光谱推测，催化作用是通过抗坏血酸的烯醇基与ＣｏＨＣＦ相互作用实现的。     

神经递质多巴胺在AQ修饰组合微电极上的伏安行为及其伏安溶出法测定

本研究了神经递质多巴胺（ＤＡ）在ＡＱ聚合物薄膜修饰组合微盘电极上的电化学行为。结果表明，在ｐＨ７．０的磷酸缓冲溶液中，修饰组合微盘电极经电化学处理后，ＤＡ的氧化还原峰电位差较小（约为８０ｍＶ），氧化峰、还原峰的峰形比较对称。在选定条件下，ＤＡ的伏安溶出峰电流与浓度在１．０×１０＾－６～８．０×１０＾－４ｍｏｌ／Ｌ范围内呈线性关系。厚的ＡＱ膜修饰组合微电极可基本上消除抗坏血酸的干扰。利用ＡＱ膜修饰     

纤维蛋白原在Pt电极上的界面电化学研究

应用电化学方法和电化学原位红外反射光谱(electrochemical in-situ FTIR)等研究了纤维蛋白原在Pt电极上的界面电化学行为.结果表明:纤维蛋白原在Pt电极上的吸附使电极的析氢与氧脱附过程减弱,影响程度随扫速的增加而增强;同样纤维蛋白原的吸附会降低亚铁氰化钾-铁氰化钾电对的氧化还原反应可逆性和电流;在-0.1~0.6V(vs.SCE)扫描范围内没有出现纤维蛋白原的特征"氧化还原"峰.电化学原位红外反射光谱测试表明纤维蛋白原在0.3~0.5V(vs.SCE)间发生化学反应,有新的产物生成.     

镓—茜素紫极谱络合吸附波的研究

在含有０．０５ｍｏｌ／Ｌ ＨＡｃ－ＮａＡｃ（ｐＨ５．６）、０．１ｍｏｌ／Ｌ ＫＣＬ和１．５×１０＾－５ｍｏｌ／Ｌ茜素紫的溶液中，镓（Ⅲ）－茜素紫络合物在单扫示波极谱仪上产生一灵敏的导数极谱波，峰电位在－１．１１Ｖ（ｖｓ．ＳＣＥ），峰电流与镓（Ⅲ）浓度在２．０×１０＾－８ｍｏｌ／Ｌ。机理研究表明，峰电流是由吸附在电极表面的络合物中的中心离子和配位体同时还原而产生的。方法已应用于铝合金中镓的测定，结果     

聚电解质中电活性物质氧化还原反应机理的现场显微红外光谱电化学研究

用现场显微红外光谱电化学方法研究了几种电活性物质,包括无机盐、有机物、无机聚合物微粒在聚电解质中的氧化还原反应及其机理。     

镓－茜素紫极谱络合吸附波的研究

在含有０．０５ｍｏｌ／ＬＨＡｃ－ＮａＡｃ（ｐＨ５．６）、０．１ｍｏｌ／ＬＫＣｌ和１．５×１０￣（－５）ｍｏｌ／Ｌ茜素紫的溶液中，镓（Ⅲ）－茜素紫络合物在单扫示波极谱仪上产生一灵敏的导致极谱波，峰电位在－１．１１Ｖ（ｖｓ．ＳＣＥ），峰电流与镓（Ⅲ）浓度在２．０×１０￣（－８）～２．０×１０￣（－６）ｍｏｌ／Ｌ范围内呈线性关系，检测限达１×１０￣（－８）ｍｏＬ／Ｌ机理研究表明，峰电流是由吸附在电极表面的络合物中的中心离子和配位体同时还原而产生的。方法已应用于铝合金中镓的测定，结果满意。     

罂粟碱的吸附伏安行为的研究

在ＮＨ３－ＮＨ４Ｃｌ底液中，罂粟碱在汞电极上有一一线性扫描还原峰，峰电位Ｅｐｃ＝－１．４４（ｖｓ．ｓａｔ．Ａｇ／ＡｇＣｌ）。该峰具有明显的吸附性。当ＰＡＰ浓度较小时，扫速较快，搅拌富集时间较长时，电极反应完全为吸附态的ＰＡＰ的还原所控制。     

阿霉素的吸附伏安法研究

阿霉素在０．１ｍｏｌ／Ｌ ＨＡｃ－ＮａＡｃ底液，富集电位－０．２０Ｖ，富集时间１２０ｓ，扫速１００ｍＶ／ｓ等条件下，于悬汞电极上产生一灵敏的吸附伏安还原峰，峰电位为－０．４５ＢＶ，峰电流与ＡＤＭ浓度为１．０×１０１０＾－９－４．０×１０＾－７ｍｏｌ／Ｌ范围内呈线性关系，检测限可达５．０×１０＾－１０ｍｏｌ／Ｌ。     

共价键联的多金属氧酸盐/SBA-15介孔杂化材料的电化学性质研究

采用循环伏安法和碳糊电极, 考察了用共缩合法和二次嫁接法合成的多金属氧酸盐(POM)/SBA-15介孔杂化材料的电化学性质以及氧化还原性能. 在乙腈介质和所检测的电势范围内, 溶液中游离的 物种和浸渍负载于介孔氧化硅上的同样POM物种显示两对W^VI单电子氧化还原峰; 共价键联于介孔氧化硅上的 物种也显示两对峰, 但第一对峰的峰电流增大, 还原电位比浸渍样品正移, 表明共价键联的POM不仅能够保持其原有的氧化还原性能, 而且比浸渍负载的POM具有更强的氧化性. 峰流～扫速的关系显示, 在低扫速时, 样品的氧化还原过程是表面控制的; 在高扫速时, 则是扩散控制的. 另外, 钨磷酸盐样品的氧化性大于钨硅酸盐样品; 共缩合法和二次嫁接法合成的样品具有相似的电化学行为.     

葡萄糖在亚硝基五氰合铁酸铁修饰碳糊电极上的电化学行为研究

采用亚硝基五氰合铁酸铁(FePCNF)粉末与碳粉质量比为2∶3混合,制备了FePCNF修饰碳糊电极.研究了FePCNF修饰碳糊电极在KNO3溶液中的电化学行为和扫速、pH值及不同支持电解质的影响.该电极可用于催化氧化检测葡萄糖.实验表明:FePCNF修饰碳糊电极在0.5 mol/L KNO3溶液中有一对灵敏的氧化还原峰,峰电流与扫速呈线性关系.氧化峰电流与葡萄糖的浓度在2.0×10-6～2.4×10-5 mol/L之间有良好的线性关系(r=0.9934),检出限为6.3×10-7 mol/L.该电极具有良好的稳定性和重现性,适合于微量葡萄糖的检测.     

新法制备铁氰化钴修饰玻碳电极及多巴胺的电催化氧化

新法制备铁氰化钴修饰玻碳电极及多巴胺的电催化氧化     

Effects of a Surfactant on the Electrocatalytic Activity of Cobalt Hexacyanoferrate Modified Glassy Carbon Electrode Towards the Oxidation of Dopamine

The cobalt hexacyanoferrate film (CoHCF) was deposited on the surface of a glassy carbon (GC) electrode with a potential cycling procedure in the presence and absence of the cationic surfactant, cetyl trimethylammonium bromide (CTAB), to form CoHCF modified GC (CoHCF/GC) electrode. It was found that CTAB would affect the growth of the CoHCF film, the electrochemical behavior of the CoHCF film and the electrocatalytic activity of the CoHCF/GC electrode towards the electrochemical oxidation of dopamine (DA). The reasons of the electrochemical behavior of CoHCF/GC electrode influenced by CTAB were investigated using FTIR and scanning electron microscope (SEM) techniques. The apparent rate constant of electrocatalytic oxidation of DA catalyzed by CoHCF was determined using the rotating disk electrode measurements.     

以碳纳米管为支撑电沉积制备高电活性与电催化性能的六氰合铁酸钴纳米多孔薄膜

以碳纳米管(MWNTs)修饰的碳糊电极为基底电极,通过电沉积方法制备了六氰合铁酸钴(CoHCF)纳米多孔生物传感平台。考察了MWNTs对CoHCF沉积的影响,优化了CoHCF沉积的各种实验条件(0.5mol/L KCl,1 mmol/L CoCl2和0.9 mmol/L K3Fe(CN)6混合溶液,在循环伏安电压范围0～1.1 V内扫20圈,扫速100 mV/s),借助循环伏安法、交流阻抗法和扫描电镜法对修饰电极进行了表征。由于MWNTs的支撑作用,电沉积得到的CoHCF呈现出多孔结构和良好的电化学稳定性。具有纳米多孔结构的MWNTs-CoHCF薄膜能有效地促进生物小分子在电极上的电子交换,维生素B2在纳米多孔CoHCF/MWNTs上具有优异的氧化还原行为,其测定线性范围为1.2×10-7～2.6×10-7mol/L,检出限为8.9×10-8mol/L。     

Amperometric determination of paracetomol by a surface modified cobalt hexacyanoferrate graphite wax composite electrode

A stable electro active thin film of cobalt hexacyanoferrate (CoHCF) was deposited on the surface of an amine adsorbed graphite wax composite electrode using a simple method. Cyclic voltammetric experiments showed two pairs of well defined peaks for this CoHCF modified electrode which exhibited excellent electrocatalytic property for the oxidation of paracetomol at a reduced overpotential of 100 mV and over a concentration range of 3.33 × 10⁻⁶ to 1.0 × 10⁻³ M with a slope of 0.208 μA/μM with good sensitivity. The influence of the supporting electrolyte on peak current and peak potential were also obtained in addition with effects of common interference (e.g., ascorbic acid) on the response of the modified electrode. Various parameters that influence the electrochemical behavior of the modified electrode were optimized by varying scan rates and pH. Electrochemical impedance spectroscopy studies suggested that the electrode reaction of the CoHCF film is mainly controlled by transport of counter ion. The immobilized CoHCF maintained its redox activity showing a surface controlled electrode reaction with the electron transfer rate constant (K_s) of 0.94 s⁻¹ and charge transfer coefficient of 0.42. Hydrodynamic and chronoamperometric studies were done to explore the utility of the modified electrode in dynamic systems. The results of the differential pulse voltammetry (DPV) using the modified electrode was applied for the determination of paracetomol in commercially available tablets. The results obtained reveal that the electrode under study could be used as an effective sensor for online monitoring of paracetomol.     

Electrocatalytic oxidation of hydrazine at cobalt hexacyanoferrate- modified glassy carbon, Pt and Au electrodes

The electrocatalytic oxidation of hydrazine has been studied on glassy carbon, Pt and Au electrodes modified by cobalt hexacyanoferrate (CoHCF) using cyclic voltammetry and rotating disc techniques. It has been shown that the oxidation of hydrazine to nitrogen occurs at the potential coinciding with that of Co(II) to Co(III) transformation in a CoHCF film, where no oxidation signal is observed at a bare glassy carbon electrode. A Tafel plot, derived from RDE voltammograms, exhibits a slope of 150 mV, indicating a one-electron charge transfer process to be the rate-limiting step. The electrocatalytic efficiency of the modified electrode towards hydrazine oxidation depends on solution pH, and the optimum range was found to be located between pH 5 and pH 7. The kinetic behaviour and location of the electrocatalytic process were examined using the W.J. Albery diagnosis table, and it was concluded that the reaction has either a “surface” or a “layer” reaction mechanism. Pt- and Au-CoHCF-modified electrodes show no significant electrocatalytic activity towards hydrazine oxidation. Received: 25 April 1997 / Accepted: 12 August 1997     

Amperometric sensor for the determination of ascorbic acid based on Cobalt hexacyanoferrate modified electrode fabricated through a new route

A new approach was attempted to prepare a chemically modified electrode using Cobalt hexacyanoferrate (CoHCF) as the redox mediator and to study its stability and electrocatalytic activity for ascorbic acid (AA) oxidation. The basic principle underlying the electrode modification is the coordination of cobalt ion with the amino nitrogen of aniline adsorbed on the surface of a graphite rod. This surface was subsequently derivatized with ferrocyanide to get CoHCF film on the electrode surface. The CoHCF modified electrode as prepared above was characterized using cyclic voltammetry. The effect of scan rate, supporting electrolyte and pH of the medium on the performance of the modified electrode was investigated. The CoHCF modified electrode exhibited good electrocatalytic activity towards the oxidation of ascorbic acid and gave a linear response from 5.52 x 10(-5) M to 3.23 x 10(-2) M with a correlation coefficient of 0.9929. The detection limit was found to be 3.33 x 10(-5) M. Hydrodynamic voltammetry and chronoamperometry studies for the oxidation of ascorbic acid were also carried out. The electrode was highly stable and exhibited good reproducibility. This modified electrode was also applied for the determination of ascorbic acid in commercial samples.     

Determination of thiol compounds in rat striatum microdialysate by HPLC with a nanosized CoHCF-modified electrode

A cobalt hexacyanoferrate (CoHCF) nanoparticle (size ca. 60 nm) chemically modified electrode (CME) was fabricated and the electrochemical behavior of thiols at this nanosized CoHCF CME was studied. In comparison with a bare glassy carbon (GC) electrode and with a general CoHCF CME which was electrodeposited in the traditional manner, the present nanosized CoHCF CME efficiently performed electrocatalytic oxidation for glutathione (GSH) and L-Cysteine (L-Cys) with relatively high sensitivity, outstanding stability, and long-life. Combined with high-performance liquid chromatography (HPLC), the nanosized CoHCF CME was used for electrochemical determination (ECD) of GSH and L-Cys. The peak currents were a linear function of concentrations in the range 2.0×10^–7 to 2.0×10^–4 mol L^–1 for both GSH and L-Cys, with detection limits of 1.2×10^–7 and 1.0×10^–7 mol L^–1, respectively. Coupled with microdialysis sampling, the HPLC–ECD system has been successfully used to assess the GSH and L-Cys content of rat striatum.     

Deposition and characterization of a CoHCF nanorod array in a templated ormosil film on an electrode and application to electrocatalysis

Cobalt hexacyanoferrate (CoHCF) was electrodeposited into an organically modified silica (ormosil) film with a nanoarray of parallel, cylindrical channels, which were obtained using 20-nm poly(styrene sulfonate), PSS, beads as a templating agent. The PSS was bound to the electrode surface with 3-aminopropyltriethoxysilane, APTES. Methoxytrimethylsilane was the ormosil precursor. Electrochemically assisted processing at a positive potential where the hydrogen ion catalyst was generated was used to deposit the ormosil film. Subsequently, the PSS and APTES were removed to provide the pores. The CoHCF was deposited in the 20-nm channels by cyclic voltammetry of a freshly prepared K₃Fe(CN)₆, CoCl₂ mixture with 1.0 mol dm^?3 KCl as the supporting electrolyte. Limiting the number of electrodeposition cycles to 10–20 resulted in CoHCF nanorods in the pores, whereas with 50 cycles bulk-form CoHCF spilled over the outer ormosil surface. Electrocatalytic oxidation of cysteine was successfully performed on these nanorod arrays, which showed greater catalytic activity than bulk-form CoHCF.     

Characterization and Electrocatalytic Property of Cobalt Hexacyanoferrate Film on Carbon Nanotubes Modified Gold Electrode

Abstract

Cobalt hexacyanoferrate (CoHCF) film was formed on multiwalled carbon nanotubes (MWNTs) modified gold electrode by electrodeposition from 0.5 M KCl solution containing CoCl₂ and K₃Fe(CN)₆. The electrochemical behavior and the electrocatalytic property of the modified electrode were investigated. Compared with CoHCF/gold electrode, the CoHCF/MWNTs/gold electrode exhibits greatly improved stability and enhanced electrocatalytic activity toward the oxidation of thiosulfate. A linear range from 5.0×10^?5 to 6.5×10^?3 M (r=0.9990) for thiosulfate detection at the CoHCF/MWNTs/gold electrode was obtained, with a detection limit of 2.0×10^?5 M (S/N=3).     

纳米CoHCF修饰电极的制备及其对血红蛋白的电化学测定研究

A cobalt hexacyanoferrate （CoHCF） nanoparticle （size ca. 60 nm） chemically modified electrode （CME） was fabricated and the electrochemical behavior of hemoglobin （Hb） at this nanosized CoHCF CME was studied. In comparison with a bare glassy carbon electrode （GCE） and a general CoHCF CME electrodeposited in a traditional manner, the present nanosized CoHCF CME performed efficiently electrocatalytic reduction for Hb with relatively high sensitivity, stability, and longlife, Combined with liquid chromatography （LC）, the nanosized CoHCF CME was used as the electrochemical detector of Hb in the established flow injection analysis-electrochemical determination （FIA-ECD） system. The peak current was a linear function of concentrations in the range from 2.5×10^-8 to 5.0×10^-6mol/L for Hb, with detection limit of 1.4×10^-8 mol/L. The FIA-ECD system has been successfully applied to assess the Hb content of clinic blood samples with advantages of sensitiveness, speediness, easy control and small sample-consumption.