隐丹参酮的电化学性质及其与DNA相互作用的研究

利用循环伏安法(CV)、线性扫描伏安法(LSV)、方波伏安法(OSWV)等电化学技术研究了隐丹参酮在玻碳电极(GCE)上的电化学氧化过程,并用计时电量法和恒电位库仑电解法等对其在电极表面的吸附行为及氧化还原机理进行了探讨.此外利用自组装DNA修饰玻碳电极研究了隐丹参酮与DNA之间的相互作用.     

大黄酸微分脉冲伏安法的研究和应用

利用循环伏安法(CV)、线性扫描伏安法(LSV)、方波伏安法(SWV)和微分脉冲伏安法(DPV)等现代电化学技术,对大黄酸在玻碳电极(GCE)上的电化学氧化还原行为以及电极反应机理进行了研究,同时还建立一种灵敏的测定大黄酸的分析方法.实验结果表明,在 pH 4.6的B R缓冲液中,大黄酸在 0.492 V(vs.SCE)电位处产生灵敏的微分脉冲阴极还原峰, 该还原峰的峰电流值与大黄酸的浓度在 4.0×10-7 mol/L~1.0×10-5 mol/L范围内呈良好的线性关系,最低检测限(D = 3σ/K)为3.9×10-8 mol/L.该法已成功地用于大黄碳酸氢钠片剂和兔血清中大黄酸的测定,结果令人满意,其回收率介于90.0%~100.1% 之间.并进一步对大黄酸在玻碳电极(GCE)上的电化学反应机理进行了探讨.     

兰索拉唑的电化学分析

在NaH2 PO4-Na2 HPO4溶液中,用循环伏安法、差分脉冲伏安法(DSV)和方波伏安法(SWV)在玻碳电极(GCE)上对兰索拉唑进行了电化学研究,发现兰索拉唑在-1.3伏左右有一个明显的阴极还原峰,考察了不同底液及pH、扫描速度、富集时间和静止时间的影响,DSV法线性范围为6.0×10-6～ 1.0×10-3m...     

硫脲对镍电沉积的作用

应用循环伏安和阻抗＿电位法研究了硫脲(TU)对玻碳电极和镀镍玻碳电极上镍沉积过程的影响.结果表明,在玻碳电极上镍的电沉积呈现明显的电化学成核机理,而在镀镍玻碳电极上则无此特征.TU的存在虽阻碍了Ni晶核的形成,但却能加速晶粒的生长.     

多壁纳米管修饰电极电催化3,4-二羟基苯甲酸研究

应用循环伏安(CV)和方波伏安(SWV)法研究3,4-二羟基苯甲酸(DHBA)在多壁碳纳米管修饰的玻碳电极上的电化学行为.实验表明:该修饰电极对DHBA有较强的电催化作用.由方波伏安法测定的氧化峰电流在DHBA浓度为4.0×10-6~1.0×10-4mol/L和2.0×10-4~8.0×10-4mol/L范围内分段呈线性变化关系;相关系数各为0.9995和0.9992,检测限1.0×10-6mol/L.     

石墨烯修饰玻碳电极在对苯二酚存在下选择性测定米吐尔

制备了石墨烯修饰玻碳电极(GN/GCE)。 在0.5 mol/L HAc-NaAc(pH=4.8)缓冲溶液中,用循环伏安法(CV)和方波伏安法(SWV)研究了米吐尔在修饰电极上的电化学行为,建立了测定米吐尔的新方法。 研究表明,米吐尔在GN/GCE上的氧化、还原峰电势差比其在裸玻碳电极(GCE)上的小,峰电流显著增加,说明GN/GCE对米吐尔有电催化作用;共存物对苯二酚干扰米吐尔的测定,通过方波伏安法可以消除其干扰。 在方波伏安曲线上,米吐尔的还原峰电流与其浓度在8.0×10^-8~5.0×10^-5 mol/L范围内呈线性关系,检出限为2.0×10^-8 mol/L。 该法可用于照相显影废液中米吐尔的测定。     

玻碳电极上Ru（bpy）3^2＋的吸附及其电致化学发光的研究

通过电化学循环伏安法和电致化学发光方法,研究了Ru(bpy)32 在玻碳电极上的吸附,研究结果表明,2Ru(bpy)3 的浓度和与玻碳材料接触的时间,直接影响了Ru(bpy)32 在玻碳上的吸附.还考察了吸附的Ru(bpy)32 在玻碳电极上被氧化后脱附的情况.     

抗菌素痢菌净的电化学分析

采用循环伏安法(CV)、差分脉冲伏安法(DPV)和方波伏安法(SWV)在玻碳电极(GCE)上对痢菌净进行了电化学研究.实验表明:在pH=6.6的B-R缓冲底液中,痢菌净在-0.85伏左右有一个明显的可逆氧化还原峰,考察了不同底液及pH值、扫描速度、富集时间和静止时间的影响.DPV法其线性范围为2.0×10-6mol/L～2.0×10-3mol/L,检出限为5.0×10-8 mol/L;SWV法其线性范围为2.0×10-6 mol/L～1.0×10-3 mol/L,检出限为2.0×10-8 mol/L.并对痢菌净的电极反应机理进行了初步探讨,该方法操作简单、灵敏,可用于实际药品测定.     

萘乙酸在多壁碳纳米管-离子液体复合修饰电极上的电催化氧化及电分析方法

运用循环伏安法(CV),计时库仑法(CC),计时电流法(CA)研究了萘乙酸(NAA)在玻碳电极(GCE),多壁碳纳米管修饰玻碳电极(MWCNTs/GCE)和多壁碳纳米管-离子液体修饰玻碳电极(MWCNTs-IL/GCE)上的电化学行为及电化学动力学性质.实验结果表明,NAA在GCE电极上于1.00V附近有一不可逆氧化峰...     

玻碳电极上Ru(bpy)23+的吸附及其电致化学发光的研究

通过电化学循环伏安法和电致化学发光方法,研究了Ru(bpy)23+在玻碳电极上的吸附,研究结果表明,Ru(bpy)23+的浓度和与玻碳材料接触的时间,直接影响了Ru(bpy)23+在玻碳上的吸附.还考察了吸附的Ru(bpy)23+在玻碳电极上被氧化后脱附的情况.     

络合吸附催化循环叠式方波伏安法

对受前行化学反应控制的络合吸附催化体系循环叠式方波伏安法进行了理论推导和实验验证，讨论了电流的特性。结果表明，对于络合吸附催化体系的测定，循环叠式方波伏安法的灵敏度比现行方波伏安法高约２５倍。     

A new strategy for simultaneous determination of cysteamine in the presence of high concentration of tryptophan using vinylferrocene-modified multiwall carbon nanotubes paste electrode

The electro-oxidation of cysteamine (CA) and tryptophan (TP) were studied by vinylferrocene-modified carbon nanotubes paste electrode using cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, and square wave voltammetry. This modified electrode exhibits persistent electron-mediating behavior followed by well-separated oxidation peaks towards CA and TP with decreasing their overpotentials. For the mixture containing CA and TP, the peaks potential well separated from each other. Using the modified electrode, the kinetics of CA electrooxidation was considerably enhanced by lowering the anodic overpotential through a catalytic fashion. Using square wave voltammetry, simultaneous determination of AC and TP has been explored at the modified electrode. Their square wave voltammetrics peaks current increased linearly with their concentration at the ranges of 0.09–500 and 5.0–1,000?μM, respectively with the detection limits of 0.05 and 1.0?μM, respectively. The modified electrode was successfully used for the determination of the analytes in real samples with satisfactory results.     

络合吸附催化不可逆循环叠式方波伏安法

研究了络合吸附催化不可逆体系受前行化学反应控制（Ｋ＜＜１）和不受前行化学反应控制（Ｋ＞＞１）两种情况下的循环叠式方波伏安法的电流理论，并进行了实验验证，讨论了电流特性，获得区分Ｋ＜＜１和Ｋ＞＞１的判据。对于上述体系的测定，循环叠式方波伏安法的灵敏度比普通差式采样方波伏安法高一个数理级以上。     

Electrochemical Determination and in silico Studies of Fludarabine on NH2 Functionalized Multiwalled Carbon Nanotube Modified Glassy Carbon Electrode

A sensitive voltammetric technique has been developed for the determination of Fludarabine using amine‐functionalized multi walled carbon nanotubes modified glassy carbon electrode (NH₂‐MWCNTs/GCE). Molecular dynamics simulations, an in silico technique, were employed to examine the properties including chemical differences of Fludarabine‐ functionalized MWCNT complexes. The redox behavior of Fludarabine was examined by cyclic, differential pulse and square wave voltammetry in a wide pH range. Cyclic voltammetric investigations emphasized that Fludarabine is irreversibly oxidized at the NH₂‐MWCNTs/GCE. The electrochemical behavior of Fludarabine was also studied by cyclic voltammetry to evaluate both the kinetic (k_s and E_a) and thermodynamic (ΔH, ΔG and ΔS) parameters on NH₂‐MWCNTs/GCE at several temperatures. The mixed diffusion‐adsorption controlled electrochemical oxidation of Fludarabine revealed by studies at different scan rates. The experimental parameters, such as pulse amplitude, frequency, deposition potential optimized for square‐wave voltammetry. Under optimum conditions in phosphate buffer (pH 2.0), a linear calibration curve was obtained in the range of 2×10^?7 M–4×10^?6 M solution using adsorptive stripping square wave voltammetry. The limit of detection and limit of quantification were calculated 2.9×10^?8 M and 9.68×10^?8 M, respectively. The developed method was applied to the simple and rapid determination of Fludarabine from pharmaceutical formulations.     

对位叠式循环方波伏安法：Ⅱ.平行催化体系

本文提出平行催化体系的对位叠式循环方波伏安法，并对共作了系统的研究，推导了这一方法的催化电流理论方程，并用验验证这理论的正确性，得到其各脉冲电流皆为同方向，对位叠式循环催化电流相当于将电流叠加４次，而波形不受方波幅度大小的影响，因而灵敏度和分辨率有较大提高，优于其它方波伏安法。     

Direct determination of brucine by square wave voltammetry on 4-amino-2-mercaptopyrimidine self-assembled monolayer gold electrode

4-Amino-2-mercaptopyrimidine self-assembled monolayer (AMP SAMs/Au) was prepared on a gold electrode. The AMP SAMs/Au was characterized by using attenuated total reflection-fourier transform infrared (ATR-FTIR) and A.C. Impedance. The electrochemical behavior of brucine on AMP SAMs/Au was studied by cyclic voltammetry (CV) and square wave adsorptive stripping voltammetry (SWASV). The modified electrode showed an excellent electrocatalytic activity for the redox of brucine. The catalytic current increased linearly with the concentration of brucine in the range of 4.0 x 10(-7) to 2.0 x 10(-4) mol l(-1) by square wave voltammetry response. The detection limit was 6.0 x 10(-8) mol l(-1).     

Electrochemical extraction of ytterbium from LiCl–KCl-YbCl3-ZnCl2 melt by forming Zn–Yb alloys

Journal of Solid State Electrochemistry - The electrochemical behavior of Yb(III) was studied at a W electrode in LiCl–KCl–ZnCl2 molten salt system. Cyclic voltammetry, square wave...     

Redox Mechanism and Evaluation of Kinetic and Thermodynamic Parameters of 1,3‐Dioxolo[4,5‐g]pyrido[2,3‐b]quinoxaline Using Electrochemical Techniques

The electrochemical behavior of a biologically important heterocyclic compound, 1,3‐dioxolo[4,5‐g]pyrido[2,3‐b]quinoxaline was investigated by cyclic, square wave and differential pulse voltammetry in solutions of different pH. Kinetic and thermodynamic parameters like standard rate constant, diffusion coefficient, apparent energy of activation_, standard Gibbs free energy and enthalpy and entropy changes were evaluated. Limits of detection and quantification were determined by square wave voltammetry. The redox mechanism of the compound was proposed on the basis of experimental results. Computational chemistry was used as a tool for the verification of experimental outcomes and assessment of different theoretical parameters     

用微机电化学系统研究方波伏安法和循环方波伏安法——Ⅰ.可逆过程的理论和验证

本文应用微计算机电化学系统研究可逆过程的方波伏安法,特别是作者提出的循环方波伏安法,建立了循环方波伏安法的理论电流函数表示式。理论和实验验证都表明,循环方波伏安法正向扫描的峰电流和峰电势分别等于逆向扫描的峰电流和峰电势,这是氧化态和还原态都溶于电解质溶液的可逆电极过程体系的重要特征和判据。同时研究了参数如方波振幅(E_sw),方波周期(τ),阶梯电势增量(ΔE)的影响,理论预期与实验结果一致。     

New Aspects of Protein‐film Voltammetry of Redox Enzymes Coupled to Follow‐up Reversible Chemical Reaction in Square‐wave Voltammetry

Protein‐film square‐wave voltammetry of uniformly adsorbed molecules of redox lipophilic enzymes is applied to study their electrochemical properties, when a reversible follow‐up chemical reaction is coupled to the electrochemically generated product of enzyme's electrode reaction. Theoretical consideration of this so‐called “surface ECrev mechanism” under conditions of square‐wave voltammetry has revealed several new aspects, especially by enzymatic electrode reactions featuring fast electron transfer. We show that the rate of chemical removal/resupply of electrochemically generated Red(ads) enzymatic species, shows quite specific features to all current components of calculated square‐wave voltammograms and affects the electrode kinetics. The effects observed are specific for this particular redox mechanism (surface ECrev mechanism), and they got more pronounced at high electrode kinetics of enzymatic reaction. The features of phenomena of “split net‐SWV peak” and “quasireversible maximum”, which are typical for surface redox reactions studied in square‐wave voltammetry, are strongly affected by kinetics and thermodynamics of follow‐up chemical reaction. While we present plenty of relevant voltammetric situations useful for recognizing this particular mechanism in square‐wave voltammetry, we also propose a new approach to get access to kinetics and thermodynamics of follow‐up chemical reaction. Most of the results in this work throw new insight into the features of protein‐film systems that are coupled with chemical reactions.