多次半微分同位镀汞电化学溶出法的理论研究及应用

近年来,应用半微分电分析法于同位镀汞电极阳极溶出,能提高灵敏度和分辨力。将该法的半微分进行多次微分而得到的1.5次和2.5次微分法,比半微分法具有更高的灵敏度和分辨力,但其理论曲线尚未见报道,对其特性还缺少理论上的定量说明。本文在半微分方程的基础上,用数字电子计算机进行运算,推导得1.5次和2.5次微分法的     

控制卷积量变化的电化学方法研究(Ⅰ)——简单电极反应

本文提出了一种控制卷积量变化的实验方法。对简单电极反应进行了理论处理,得到了恒半积分法、半积分扫描法、半微分扫描法的理论方程,并对3个体系进行了实验验证,结果与理论分析基本吻合。     

四甲铵阳离子在水/硝基苯界面传输的新极谱法研究

本文采用新极谱法, 包括半积分, 半微分, 1.5次微分及2.5次微分新极谱研究了四甲铵离子在水/硝基苯界面的传输, 从理论上讨论了峰高, 峰电位及峰宽对传输质点浓度, 扫描速率等因系的依赖关系, 用模拟电子线路在实验上对离子在两相界面传输的新极谱法理论进行了验证, 实验与理论接近, 得到了与金属电极/电解质溶液界面的氧化还原类似的结果.     

基于微型计算机的1.5次微分极谱法

作者研制了一个实时钟控制的高精度数据采集和处理系统,用于采集和处理了双组分体系悬汞电极线性扫描伏安数据。原始数据经过九点最小二乘法平滑滤波,利用卷积变换算法程序处理,得到了半积分、半微分和1.5次微分极谱图。这种基于微型计算机的新极谱法与电子模拟仪器相比,能更好地消除噪声干扰,改善分析方法的灵敏度和分辨率。     

超微电极上半微分电分析法

介绍了超微半球电极上具有简单反应时的半微分循环伏安理论。理论表明,超微电极上半微分电流与电活性物质的浓度成正比,并据此提出了一种利用超微半球电极上半微分曲线进行电化学分析测量的新方法。该法具有灵敏度高、分辨率好等特点。     

控制卷积量变化的电化学方法理论与应用：———伴有后续均相催化 …

采用电流与时间的卷积作为可控制量的电化学实验方法,对伴有后续均相催化反应的电极过程进行了理论处理,得到了恒半积分法、半积分扫描法和半微分扫描法的理论曲线,并对三氯化铁－双氧水体系进行了实验验证,获得隍续均相催化反应的动力学速率常数,结果与文献值吻合。     

控制卷积量变化的电化学方法理论与应用——伴有后续均相催化反应的电极过程(Ⅱ)

采用电流与时间的卷积作为可控制量的电化学实验方法,对伴有后续均相催化反应的电极过程进行了理论处理,得到了恒半积分法、半积分扫描法和半微分扫描法的理论曲线,并对三氯化铁——双氧水体系进行了实验验证,获得了后续均相催化反应的动力学速率常数,结果与文献值吻合。     

控制卷积量变化的电化学方法研究：伴有后续均相催化反应的电极过程（Ⅰ）

采用控制卷积量的化学实验方法，对伴有后续均相催化反应的电极过程进行了处理，得到恒半积分法，半积分扫描法和半微分扫描法的理论曲线，并对亚铁氰化钾－抗坏血酸体系进行了实验验证，获得后续均相催化反应的动力学速率常数，与文献值吻合。     

科研成果简介

新极谱法是近年来刚发展起来的极谱新方法。该方法由于具有半积分,半微分和多重半微分等功能,所以它的灵敏度比经典极谱法提高2—3个数量级。 目前,国内外尚无此类仪器正式商品出售,我所用国产元件研制成一台多功能新极谱仪,它可以记录电流(i)的革积分值、半微分值,1.5次微分值,2.5次微分值和相应电位(E)的曲线,及其循     

新极谱法

新极谱法包括①半积分电分析法,系记录电流的半积分m和电压E的关系曲线。②半微分电分析法,系记录电流的半微分e和电压E的关系曲线。③1.5次微分和2.5次微分极谱法,系记录电流的1.5次微分e＇或2.5次微分e＂和电压E的关系曲线。自1972年Oldham首次提出半积分电分析法以来,此类方法经完善和发展已用于多种极谱技术。例如线性扫描伏安法,循环伏安法,阶梯波极谱法方波极谱法,阳极溶出伏安法等。其灵敏度和分辨能力均已近于脉冲极谱法,且具有许     

Voltammetric current–potential calculations using infinite series solution

Highly accurate analytical solution contributing to the theory of linear sweep voltammetry for single scan experiments is given by application of exponential infinite series. The cases of reversible or irreversible charge transfer with or without coupled chemical reaction are treated and calculated results are compared with the customary solution of Nicholson and Shain. Problems with partial divergence of the series were overcome by the series transformation and the use of arbitrary precision arithmetic.     

微环电极上线性扫描伏安法准稳态可逆波理论

本文求得了适用于不同γ(式(6))和P(式(9))的最大电流表达式,并提出了准稳态的定量标准,还推导了微环电极上线性扫描伏安法准稳态可逆波方程式,经验证,理论和实验结果相符合     

General expression of the linear potential sweep voltammogram in the case of diffusionless electrochemical systems

The equation of the linear potential sweep voltammogram is derived for any degree of reversibility of the electrochemical reaction for the following methods: surface voltammetry when both the oxidized and the reduced forms are strongly adsorbed, and a Langmuir isotherm is obeyed, thin layer voltammetry, and linear potential sweep coulometry. The results are expressed in one mathematical form valid for the three cases. The transfer coefficient and the rate constant of the electrochemical reaction can be deduced from an experimental study of the variations of the peak potentials as a function of the sweep rate.     

A New Voltammetric Approach for Electrochemical Determination of Lamotrigine in Pharmaceutical Samples

A new linear sweep voltammetric method for quantitative lamotrigine (LMT) determination based on an electrochemically pre-treated pencil graphite electrode (PGE*) is presented. Response characteristics of the PGE* toward the mentioned compound were investigated by cyclic voltammetry and linear sweep voltammetry. The quantitative determination of LMT revealed a wide linear range of 2.5 ⋅ 10⁻⁵–1.0 ⋅ 10⁻³ M with a detection limit of 1.94 ⋅ 10⁻⁵ M. The method was used successfully for LMT determination in a pharmaceutical formulation.     

农药噻嗪酮在玻碳电极上的电化学行为

应用循环伏安法(CV)、线性扫描伏安法(LSV)、微分脉冲伏安法(DPV)和方波伏安法(SWV)等研究了噻嗪酮在玻碳电极上的电化学行为,并建立样品噻嗪酮的SWV测定法.噻嗪酮在玻碳电极上的电还原涉及两质子/两电子和两质子的不可逆过程.     

Sonoelectrochemically enhanced determination of 5-aminosalicylic acid

The electrochemical detection of the anti-inflammatory drug 5-aminosalicylic acid (5-ASA) has been evaluated through the application of linear sweep, square wave and sonolinear sweep voltammetry. The introduction of ultrasound is shown to significantly enhance the oxidation signal intensity thereby enabling the detection of low concentrations with the linear range (1-57 muM) adequate for assessing free drug within physiological samples. Interference from ascorbic acid can be effectively negated through the introduction of cupric ion without any appreciable cost to the voltammetric response to 5-ASA. The efficacy of employing sonolinear sweep voltammetry to the determination of this compound within a compositionally complex tissue culture medium has been assessed with the recovery of 5 muM 5-ASA found to be 102% (RSD=5%, N=3).     

Study of the Effects of Nonlinear Potential Sweeps on Voltammetry

Voltammetric methods use a constant sweep rate during the course of a scan. This paper reports a study of the influence of a nonconstant sweep rate on the voltammetric response. In this approach, either continuously increasing or continuously decreasing potential scan rates can be employed, unlike presently available methods which rely on a constant sweep rate. The voltammetric response of potassium ferrocyanide at a glassy carbon electrode was used as a model system to test the new method. The responses obtained using traditional staircase voltammetry (linear staircase voltammetry) and the new approach (nonlinear staircase voltammetry) were compared by experiment and by simulation. The new approach offers capability for signal enhancement, whereby enhanced current or enhanced peak shape can be obtained by choice of appropriate waveform parameters.     

碳素钢钝化的线性电位扫描法问题

电位扫描法是一种基本的电化学研究方法。前人对此作了大量的研究。对于具有表面转化步骤的复杂电极过程,尤其是阳极过程,Srinivasan等作了扫描电位—电流的理论分析,导出了峰值电流(I_(max)或i_p)与扫描速度的平方根(v~(1/2))成正比的近似数学关系式,可较好地应用于有机物电化学吸附,以及H_2、O_2在某些金属表面的电化学吸附。金属钝化过程是金属阳极溶出过程中含氧金属粒子在金属表面生成化学吸附层并且继续发展形成表面     

Linear-sweep voltammetry and the simultaneous determination of xanthine and xanthosine at the glassy carbon electrode

Linear sweep voltammetry of xanthine and xanthosine has been studied at a sweep rate of 10mVs⁻¹ in phosphate buffers with different pH values. Based on the linear relation of peak current versus concentration, the simultaneous determination of both the compounds was carried out.     

Studying Conditions for Measuring an Analytical Signal on a PU-2 Polarograph

Conditions for measuring an analytical signal on a superuniversal PU-2 polarograph were studied using direct-current, normal-pulse, differential-pulse, alternating-current square-wave, alternating-current sine-wave, and rapid potential sweep voltammetry modes. Dropping-mercury, static dropping-mercury, mercury–graphite, and gold–graphite electrodes were examined with a linear, triangular, and pulse potential sweep. It was demonstrated that the alternating-current square-wave mode, which can be combined with a triangular potential sweep, possesses the best sensitivity.