超微盘电极线性扫描准稳态可逆波及其导数波理论

提出超微盘电极线性扫描准稳态可逆波理论, 对伏安曲线性质进行了研究,利用铂超微盘电极及K~4Fe(CN)~6-KCl体系进行了验证, 此外, 还对超微盘电极线性扫描可逆波的一次, 二次, 三次微分进行了理论探讨。     

超微环电极上稳态伏安曲线理论和验证

本文提出了超微环电极上稳态伏安曲线理论,用K₄Fe(CN)₆·KCl体系和超微金环电极(T_i=25.7μm,T₂=20.2μm)对理论进行验证,测得的伏安曲线与理论相符。     

超微盘电极上准稳态可逆波循环伏安法理论

本文提出了超微盘电极上准稳态可逆波循环伏安理论, 并对环形氧化还原波的性质进行了深入的讨论, 选择K~4Fe(CN)~6KCl体系在铂微盘电极上对理论进行验证, 实验结果与理论相符合。     

超微盘电极上阶梯扫描伏安法可逆波理论

本文报道超微盘电极上阶梯扫描伏安法可逆波理论,对电流-电位曲线的性质进行了讨论.利用K₄Fe(CN)₆·KCl体系进行了验证,实验结果与理论相符.     

反射式薄层可见光谱电解池的制作与性能测试

设计制作了一种反射式薄层可见光谱电解池。该电解池采用光亮铂片作为工作电极,将铂丝辅助电极和Ag AgCl参比电极组装在一起。薄层池中间的溶液薄层是通过光亮铂片和覆盖其上的玻璃片之间的塑料薄膜垫圈加以控制,当液层厚度为0.2mm时,液层容积为16μL。由于采用双平行反射的光路,使入射光与出射光保持在一直线上,可以在不变更光路系统下的各种光度计上使用。在K3Fe(CN)6 K4Fe(CN)6体系中,用循环伏安法、恒电位现场光度法进行性能测试。实验结果表明,该电池具有良好的薄层光谱电化学性能,可用于薄层可见光谱电化学研究。     

线性扫描伏安法研究(Ⅲ)——超微盘电极上同时受扩散和电极反应速率控制的准稳态电流理论

本文提出了超微盘电极上受扩散和电极反应速率控制的线性扫描伏安法准稳态电流理论,对电流、电位曲线的性质进行了探讨,利用铂超微盘电极及Fe(Ⅱ)-1mol/LH₂SO₄体系进行了验证,并测定了标准电极反应速率常数(k_s)及转移系数(α)。用恒电位和线性扫描伏安法得到的实验结果与理论相符。     

大蒜中抗坏血酸的半微分伏安法测定

将工作电极直接插入大蒜瓣中，采用半微分伏安法研究了抗坏血酸的测定方法。用微铂盘电极（直径３００ μｍ）作为工作电极，在ｐＨ６.８的磷酸氢二钠－柠檬酸介质中，抗坏血酸在７.０×１０－２～３.２×１０２ｍｇ／Ｌ范围内与半微分伏安曲线阳极峰的峰高呈线性关系，其最低检出浓度为４．０×１０－２ｍｇ／Ｌ。利用ｔ检验和Ｆ检验法，将所研究方法与溶液中的标准加入法相比，对相同样品的测定结果无显著性差异。     

双荼电极参比电位采样快扫伏安方法

报道一种双铂盘工作电极、相应的毛细管参比电极和竖直工电化学池设计并用于快速循环伏安测量。双工作电极包括一个常规工作电极,一个辅助工作电极。后者在使用中接地,仅提供参比电位来控制工作电极的电位。参比毛细管尖端安设在接近辅助工作电极的位置上;用０．３ｍｍ直径Ｐｔ盘工作电极,在电位扫描速度高达１０ｋＶ／ｓ都可以得到类似于１００％ｉＲ补偿的伏安曲线,而不必使用ｉＲ补偿电路。本文围绕高扫速伏安法中工作电极电     

一种新的修饰电极的制备及其应用于对苯二酚的高选择性测定

通过电聚合酸性络蓝K于多壁碳纳米管修饰玻碳电极上构建了一种新的修饰电极。研究了该电极的电化学性质,结果表明:该电极表现出优异的电催化和选择性能,可在异构体存在下伏安法选择测定对苯二酚。线性范围在1×10-6~1×10-4mol.L-1,检出限为1×10-7mol.L-1。所制作的电极对水样进行了测定所得结果与光谱法的结果一致。     

一种更新固体电极表面的新方法

由于电解产物的淀积或者电极表面的污染，在固体电极伏安法中，电极的表面状况往往发生改变，使测定结果的重现性和精密度降低。为了获得可重现的新鲜电极表面，第次测定后电极表面需要更新。在用物理方法更新电极表面时，过去常用手工擦试的方法。由于这种方法很难做到每次更新条件一致，因此，测定结果的重现性和精密度较低。作者设计的原位更新固体电极表面的方法可以提高测定结果的重现性和精密度。在同一浓度的铁溶液中，6次重复测定的相对标准偏差为0.8%。     

阳极溶出催化伏安法的理论研究 Ⅰ.可逆电极溶出

本文推导了玻璃碳电极上可逆溶出催化过程的理论电流方程、峰电流及峰电势方程,得知溶出催化伏安法所得的峰电流比溶出伏安法的峰电流提高了数十倍,从而进一步提高了溶出伏安法的灵敏度。本文还用碲的溶出催化实验验证理论方程。所得实验结果均与理论方程相吻合。     

阳极溶出催化伏安法的理论研究 Ⅱ.不可逆电极溶出

本文对在玻璃碳电极上不可逆溶出催化的理论进行了研究,推导了溶出催化过程的电流方程,峰电流和峰电势方程,并用微计算机模拟出各种关系曲线,从理论方程得知溶出催化伏安法所得的峰电流比溶出伏安法的峰电流提高了二个数量级。本文还用钯的溶出催化实验验证理论方程,所得的实验结果均与理论方程相吻合。     

A complete numerical simulation of the techniques of alternating current linear sweep and cyclic voltammetry: analysis of a reversible process by conventional and fast Fourier transform methods

We describe the method of achieving the first completely general simulation of ac linear sweep and cyclic voltammetry making use of the fully implicit Richtmyer modification (FIRM) method. The simulation technique is applied to a reversible process under conditions where a sinusoidal waveform of any amplitude is superimposed onto the dc potential which is swept at a finite scan rate. Results, where possible, are compared with the existing theory derived at constant dc potential to confirm the fidelity of the simulation. In particular, we demonstrate excellent agreement with the results of Engblom et al. [J. Electroanal. Chem. xxx (1999) xxx] for large amplitude ac voltammetry described in the companion paper immediately preceding this article. The use of conventional and Fourier transform methods of data analysis are compared to highlight the advantages of the use of the fast Fourier transform algorithm in ac voltammetry.     

Electroanalytical Determination of Morpholine as a Corrosion Inhibitor at a Cathodically Pretreated Boron-Doped Diamond Electrode

An electroanalytical method for the determination of morpholine, a corrosion inhibitor, was developed at a cathodically pretreated boron-doped diamond electrode (BDDE). The voltammetric response of morpholine at the BDDE in 0.1?mol L^?1 KCl (pH 10) shows an irreversible oxidation process at approximately 1.3?V vs. Ag/AgCl in 3.0?mol L^?1 KCl. Using cyclic voltammetry, the number of electrons involved in the morpholine electroxidation mechanism was found to be 1. The application of chronoamperometry showed that the apparent diffusion coefficient (D₀) was 2.99?×?10^?6 cm² s^?1. Using square wave voltammetry under the optimized conditions (frequency of 30.0?Hz, pulse amplitude of 100?mV and step potential of 20?mV at pH 10.0), the developed method provided limits of detection and quantification of 2.1 and 6.9?mg L^?1, respectively, with a linear range from 5.0 to 100.0?mg L^?1 (r?=?0.991). Intraday (n?=?10) and interday (two consecutive day) precision values assessed as the relative standard deviation for solutions containing 30.0, 60.0, and 90.0?mg L^?1 of morpholine were from 0.41 to 5.86% and 0.92 to 3.19%, respectively. The feasibility of the method for the interference-free determination of morpholine was verified by the analysis of synthetic boiler water samples containing CaCO₃, Na₂SO₃, Na₃PO_4, FeCl₃, and humic acid as organic matter. In addition, hydrazine was added as a possible interfering compound because of its widespread use in corrosion inhibition. Recovery values from 90.9 to 109.4% were obtained in the synthetic boiler water, thereby attesting to the accuracy of the method.     

线性扫描伏安法研究司帕沙星的电化学行为

采用线性扫描伏安法和循环伏安法研究司帕沙星的电化学行为。在0.05 mol·L~(-1)硫酸溶液中,司帕沙星于-1.29 V(vs.Ag/AgCl)处产生一灵敏的还原峰,司帕沙星的浓度在1.0×10~(-6)～1.5×10~(-4)mol·L~(-1)范围内与其峰电流呈线性关系,检出限(3S/N)为2.0×10~(-7)mol·L~(-1)。该法用于司帕沙星片剂的分析,回收率为96.2%～105.0%,相对标准偏差(n=6)为2.4%。试验证实:司帕沙星在电极上产生的峰为具有吸附性的完全不可逆的还原峰。     

Iron(III)‐mediated Electrochemical Detection of Levofloxacin in Complex Biological Samples

We report the design of an electrochemical sensor capable of detecting levofloxacin (LEVX) in complex biological samples. This detection strategy is simple, fast, and does not require sample pretreatment or electrode modification. Unlike previously developed electrochemical LEVX sensors that require direct oxidation of LEVX, the sensing mechanism is based on the complexation reactions between LEVX and iron(III), resulting in a concentration‐dependent decrease in the iron(III) reduction peak current and a shift in the peak potential. These changes are presumably attributed to the decrease in the concentration of uncomplexed Fe(III) in the solution. The concentration‐dependent change in both the current and potential can be used for quantification of LEVX in various samples, including 50 % synthetic urine and 25 % synthetic human saliva. The limit of detection was estimated to be in the range of 1.5 to 2.3 μM, concentrations that are much lower than the concentration of LEVX found in urine and saliva samples of patients administered this drug for conditions such as urinary tract infection. With further optimization, this sensing strategy could find applications in clinical pharmacokinetic studies.     

微分脉冲阴极吸附溶出伏安法测定利多卡因

用微分脉冲阴极吸附溶出伏安法测定了利多卡因针剂的含量。浓度与波高的线性范围为1×10~(-7)～3×10~(-4)mol/dm~3。最低检测限l×10~(-8)mol/dm~3。回收率98.07±0.05%。     

吡虫啉电化学性能研究

应用循环伏安法研究了吡虫啉（IDP）在玻碳电极的电化学行为. 结果表明：IDP的还原反应是不可逆的,且受扩散控制,电子转移数4,扩散系数DR 2.44×10-6cm2?s-1,反应活化能Ed 9.33 kJ?mol-1.     

Differential Pulse Voltammetric Determination of L-Cysteine After Cyclic Voltammetry in Presence of Catechol with Glassy Carbon Electrode

An electrochemical method of determination of cysteine has been developed in the solution containing catechol as the indicator. Nucleophilic addition of the thiol species to the electrogenerated o-quinone results in the formation of o-quinone-cysteine adducts that easily accumulate use at the surface of the electrode in the acidic solution. Therefore, the use of cyclic voltammetry leads to the amplification of the o-quinone-cysteine adduct's reductive current. As cyclic voltammetry was performed prior to differential pulse voltammetry, the peak of o-quinone-cysteine could be separated preferentially from o-quinone in the differential pulse voltammogram and the selectivity of the method has been assessed with no interference from ascorbic acid, glycine, L-tyrosine, or L-lysine. The magnitude of o-quinone-cysteine peak is proportional to the concentration of cysteine, and thus it can be exploited to determine cysteine within the injection. The results were consistent with those obtained by means of HPLC analysis.     

Graphene oxide modified glassy carbon electrode for determination of linagliptin in dosage form,biological fluids,and rats' feces using square wave voltammetry

An applicable square wave anodic adsorptive stripping voltammetric (SWAdASV) technique was utilized for linagliptin determination. A glassy carbon electrode was modified with graphene oxide to increase the electrode reactivity. The method is cheap, accurate, precise, and selective, with a good linearity range and a low detection limit. The proposed method was the first one to determine linagliptin in the feces, which is the main route for excreting the drug from the body. The electrode was characterized using various techniques, including Scanning Electron Microscope (SEM), Fourier-transform infrared (FTIR), and X-ray powder diffraction (XRD), and the oxidation mechanism of the drug was examined. The proposed method has a linear range of 9.45–103.96 ng mL^?1. The detection limit was 4.0 ng mL^?1. The modified electrode was employed efficiently to determine the drug in tablet formulations, spiked human urine, plasma, and rats' feces with high recoveries. The proposed method's results were statistically compared with those of another previously published method.