吸附溶出催化伏安法测定人参中的锗

本文提出了利用吸附溶出催化伏安法测定人参中锗的方法。最佳体系为:2.5×10~(-2)mol/LH_2O_2、2.0×10~(-2)mol/L邻苯二酚、2.0×10~(-3)mol/L H_2SO_4。线性范围为2.0×10~(-9)～2.0×10~(-7)mol/L。当富集时间为4 min时,最低检测浓度为4.0×10~(-10)mol/L。此法己成功地应用于测定人参中的锗。     

Adsorptive Stripping Voltammetry of Phytohemagglutinin

Abstract

The adsorptive stripping voltammetric behaviour of the lectin, phytohemagglutinin, has been optimised with respect to accumulation time, accumulation potential, pulse amplitude, scan rate and drop size. Adsorptive stripping voltammetry has also been used to study the interaction of this protein with nannose, galactose and N-acetyl-D-galactosamine.     

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。     

托美汀的吸附伏安法研究

在０．２ｍｏｌ／Ｌ ＮＨ３－ＮＨ４Ｃｌ底液中，托美汀在悬汞电极上有一灵敏的还原峰。峰电位为Ｅｐｃ＝－１．４８Ｖ，该峰具有明显的吸附性，峰电流ｉｐｃ与ＴＯＬ浓度在４．０×１０＾－９－７．０×１０＾－７ｍｏｌ／Ｌ范围内呈线性关系；检出限为５．０×１０＾－１０ｍｏｌ／ｌ，用该法测定了片剂ＴＯＬ的含量，结果良好。     

吸附溶出催化伏安法测定痕量锗

利用吸附溶出伏安法、极谱催化法测定痕量锗已有报道。但将吸附溶出伏安法与极谱催化法结合进行测定,尚未见报道。我们选择适当的体系和配位体3,4-二羟基苯甲醛(DHB)及氧化剂钒(V),首先使Ge(Ⅳ)-DHB络合物在悬汞电极上于一定电位处吸附富集一定时间,然后电位向负的方向扫描。当达到Ge(Ⅳ)-DHB络合物的还原电位时,Ge(Ⅳ)还原     

Trace Measurements of Mitomycin C Based on Adsorptive Stripping Voltammetry

Abstract

A highly sensitive voltammetric approach for trace measurements of mitomycin C is described. The method is based on controlled adsorptive accumulation of the drug at the hanging mercury drop electrode, followed by voltammetric measurement of the surface species. After five min preconcentration, a detection limit of 2 × 10^?9 M mitomycin C is obtained. The adsorptive stripping response is evaluated with respect to electrolyte, pH, preconcentration time and potential, concentration dependence, possible interferences, and other variables. The relative standard deviation at 1 times; 10^?7 M is 4%. Cyclic voltanmetry is used to characterize the redox and interfacial processes.     

Catalytic Adsorptive Stripping Voltammetry of Germanium(IV) in the Presence of Gallic Acid and Vanadium(IV)‐EDTA

A highly sensitive and selective catalytic adsorptive cathodic striping procedure for the determination of trace germanium is presented. The method is based on adsorptive accumulation of the Ge(IV)‐gallic acid (GA) complex onto a hanging mercury drop electrode, followed by reduction of the adsorbed species. The reduction current is enhanced catalytically by addition of vanadium(IV)‐EDTA. The optimal experimental conditions include the use of 0.03 mol/L HClO₄ (pH1.6), 6.0×10^?3 mol/L GA, 3.0×10^?3 mol/L V(IV), 4.0×10^?3 mol/L EDTA, an accumulation potential of ?0.10 V(vs. Ag/AgCl), an accumulation time of 120 s and a differential pulse potential scan mode. The peak current is proportional to the concentration of Ge(IV) over the range of 3.0×10^?11 to 1.0×10^?8 mol/L and the detection limit is 2×10^?11 mol/L for a 120 s adsorption time. The relative standard deviation at 5.0×10^?10 mol/L level is 3.1%. No serious interferences were found. The method was applied to the determination of germanium in ore, mineral water and vegetable samples with satisfactory results.     

Adsorptive Stripping Voltammetric Measurements of Trace Molybdenum at the Bismuth Film Electrode

Bismuth‐film electrodes on glassy‐carbon substrates have been successfully applied for adsorptive‐stripping voltammetric measurements of trace molybdenum in the presence of chloranilic acid (CAA). The procedure is based on the preconcentration of the molybdenum‐chloranilic acid complex at a preplated bismuth film electrode held at ?0.55 V (vs. Ag/AgCl), followed by a negatively‐sweeping square‐wave voltammetric scan. Factors influencing the adsorptive stripping performance, including different ligands, solution pH, CAA concentration, preconcentration time and potential, have been optimized. The response compares favorably with that observed at mercury film electrodes, and is linear over the 5–50 μg/L Mo concentration range (one min preconcentration). A detection limit of 0.2 μg/L molybdenum is obtained following a 10 min accumulation. High stability is indicated from the reproducible response of a 100 μg/L molybdenum solution (n= 60; RSD=2.6%). Applicability to seawater samples is demonstrated.     

Catalytic Adsorptive Stripping Voltammetry at a Carbon Paste Electrode for the Determination of Amiodarone

Voltammetry using solid electrodes usually suffers from the contamination due to the deposition of the redox products of analytes on the electrode surface. The contamination has resulted in poor reproducibility and overelaborate operation procedures. The use of the chemical catalysis of oxidant on the reduction product of analyte not only can eliminate the contamination of analyte to solid electrodes but also can improve the faradaic response of analyte. This work introduced both the catalysis of oxidant K2S2O8 and the enhancement of surfactant Triton X-100 on the faraday response of amiodarone into an adsorptive stripping voltammetry at a carbon paste electrode for the determination of amiodarone. The method exhibits high sensitivity, good reproducibility and simple operation procedure. In 0.2 mol·L^-1 HOAc-NaOAc buffer （pH=5.3） containing 2.2×10^-2 mol·L^-1 K2S2O8 and 0.002% Triton X-100, the 2.5th-order derivative stripping peak current of the catalytic wave at 0.3 V （vs. Ag/AgCl） is rectilinear to amiodarone concentration in the range of 2.0×10^-10-2.3×10^-8 mol·L^-1 with a detection limit of 1.5×10^-10 mol·L^-1 after accumulation at 0 V for 30 s.     

Fostering and Understanding Iron Detection at the Ultratrace Level by Adsorptive Stripping Voltammetry with Catalytic Enhancement

Iron detection at the ultratrace level in seawater is at the forefront in chemical oceanography research and analytical methodologies for its determination are actively sought. Voltammetric methods and specifically cathodic stripping voltammetry (CSV) with catalytic enhancement, are particularly fit for this purpose as they avoid any separation and pretreatment step, showing high sensitivity and robustness towards the saline matrix. Here we introduce a simplification in the instrumentation for iron detection by CSV using 2,3‐dihydroxynaphthalene (DHN) as the ligand, atmospheric oxygen as the catalytic enhancer and a small 0.5 mL cell. The simplification involves the use of a standard, non‐specialized voltammetric cup as a holder for the small cell and the introduction of a simple silver wire as a pseudoreference electrode. The latter reduces the risk of sample contamination and is perfectly suited for employment with the small, 0.5 mL volume cell. Extensive optimization was performed in both ultrapure and seawater: a square wave frequency of 10 Hz was adopted, whereas the ligand concentration did not significantly influence the limit of detection (around 10 and 40 pM for ultrapure and seawater, respectively). The latter difference in signal to noise ratio was explained by the kinetics of iron complex reduction. The method was successfully validated by the analysis of a seawater sample with consensus value.     

Adsorptive Cathodic Stripping Voltammetry for Quantification of Alprazolam

A simple and highly sensitive electrochemical sensor was developed for adsorptive cathodic stripping voltammetry of alprazolam. Based on an electrochemically pretreated glassy carbon electrode, the sensor demonstrated good adsorption and electrochemical reduction of alprazolam. The morphology of the glassy carbon electrode and the electrochemically pretreated glassy carbon electrode were characterized by scanning electron microscopy/energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The electrochemical behaviors of alprazolam were determined by cyclic voltammetry, and the analytical measurements were studied by adsorptive cathodic stripping voltammetry. Optimized operational conditions included the concentration and deposition time of sulfuric acid in the electrochemical pretreatment, preconcentration potential, and preconcentration time. Under optimal conditions, the developed alprazolam sensor displayed a quantification limit of 0.1 mg L⁻¹, a detection limit of 0.03 mg L⁻¹, a sensitivity of 67 µA mg⁻¹ L cm⁻² and two linear ranges: 0.1 to 4 and 4 to 20 mg L⁻¹. Sensor selectivity was excellent, and repeatability (%RSD < 4.24%) and recovery (82.0 ± 0.2 to 109.0 ± 0.3%) were good. The results of determining alprazolam in beverages with the developed system were in good agreement with results from the gas chromatography–mass spectrometric method.     

微分脉冲吸附溶出伏安法测定苯胺的研究

苯胺经重氮化、偶合反应定量生成的偶氮化合物具有很强的电活性。作者用微分脉冲吸附溶出伏安法测定偶氮化合物来定量分析苯胺的含量。以ＮＨ３·Ｈ２Ｏ－ＮＨ４Ｃｌ（ｐＨ＝１０）缓冲液为底液，富集电位为－０１５Ｖ，富集时间１２０ｓ，电位扫描速度４ｍＶ／ｓ，在－０６７０Ｖ处产生一个灵敏度高、峰形好的溶出峰。苯胺浓度在１０－９～１０－７ｍｏｌ／Ｌ时与峰电流成线性关系。用印染厂土壤、废水和广州垃圾填埋场的渗出液作标准回收试验，平均回收率分别为９８２％、９７０％、９７５％，测定的相对标准偏差为４３％、４０％、３３％。     

相敏交流吸附溶出伏安法测定痕量锡

本研究了锡（Ⅳ）－３，４－二羟基苯甲酸络合物的相敏交流吸附溶出行为，在ＰＨ３．６的甲酸盐缓冲溶液中，该络合物经两步双电子还原在相敏交流伏安图上于－０．３３Ｖ和－０．４９产生两个吸附还原波，第一个波更灵敏，峰电流与锡浓度在１．７×１０＾－９－２．５×１０＾－７ｍｏｌ／Ｌ范围内呈线性关系，检测限达４×１０＾－１０ｍｏｌ／Ｌ。测得络合物组成的１：１。方法已应用于罐头食品中锡的测定。结果满意。     

Carbon Paste Electrode Plated with Lead Film. Voltammetric Characteristics and Application in Adsorptive Stripping Voltammetry

A lead film plated in situ at a carbon paste support was tested as a novel, potential electrode for adsorptive stripping voltammetric determination of cobalt traces in an ammonia buffer solution. To show the practical applicability of the new electrode, a catalytic adsorptive Co system in a supporting electrolyte containing 0.1 M ammonia buffer, 5×10^?4 M nioxime and 0.25 M nitrite was selected and investigated as a model solution. Pb and Co ions were simultaneously accumulated in situ on the electrode surface: Pb ions electrochemically at ?1.3 V) and then at ?0.75 V, at which potential the Co(II)‐nioximate complex was also pre‐concentrated via adsorption. Instrumental parameters, such as the time of nucleation and formation of Pb film deposits, the time of accumulation of the Co‐nioxime complex at the PbF/CPE, and the procedures of electrode regeneration, were optimized to obtain good reproducibility and sensitivity of the Co response. The optimized procedure yields favorable and highly stable stripping responses with good precision (RSD=3% for a 5×10^?8 M Co) and good linearity (up to 5×10^?7 M, coefficient of determination, R=0.996). The detection limit was 4×10^?10 M Co (0.023 μg L^?1) for an accumulation time of 120 s. The method enables the determination of Co in the presence of high excesses of Ni or Zn. The voltammetric data were correlated with the structural characterization by scanning electron microscopy (SEM) and X‐ray fluorescence spectroscopy (XRF).     

氟哌啶醇的吸附伏安法研究

于NH_3-NH_4Cl底液中,氟哌啶醇(Hal)在悬汞电极上有一灵敏的还原蜂。EPC为-1.55V(vs饱和Ag/AgCl电极),其线性扫描吸附伏安法的线性范围为5.0×10~(-9)～9.0×10~(-7)mol/L。最低检测限为2.0×10~(-9)mol/L。测定了用药患者的尿样及针剂,片剂中Hal的含量,结果满意。对Hal在汞电极上的电化学性质,特别是吸附性进行了探讨。     

Adsorptive Stripping Square-Wave Voltammetry of Creatine

ABSTRACT

An adsorptive stripping square-wave voltammetric method for quantitative determination of creatine is developed. The basic redox properties of creatine are investigated by means of square-wave and cyclic staircase voltammetry. Creatine undergoes an irreversible reduction in neutral and acidic medium at a hanging mercury drop electrode. The square-wave voltammetric response of creatine depends on the parameters of the SW excitation signal as well as on the concentration and type of the supporting electrolyte, the accumulation time and the potential and pH of the medium. The optimal experimental conditions for quantitative determination of creatine are as follows: supporting electrolyte 0.1 mol/L KNO₃ buffered with 0.1 mol/L acetate buffer to pH = 4 and accumulation potential -1.2 V. The optimal SW parameters found are: frequency f = 120 Hz, amplitude E _sw = 30 mV, and scan increment dE = 4 mV. A detection limit of 6.6 x 10^?8 mol/L creatine was obtained after 30 s preconcentration period at accumulation potential -1.2 V. The correlation coefficients of the calibration curves at concentration levels of 10^?7 to 10^?5 mol/L creatine are greater than 0.99. The results of recovery tests range from 92.18% to 102.51%.     

Adsorptive Cathodic Stripping Voltammetry Determination of Ultra Trace of Lead in Different Real Samples

Abstract

In the present work, an adsorptive cathodic stripping voltammetric method using a hanging mercury drop electrode (HMDE) was described in order to determine the ultra trace of lead ions with carbidopa in different real samples. The method is based on accumulation of lead metal ion on mercury electrode using carbidopa as a suitable complexing agent. The potential was scanned to the negative direction and the differential pulse stripping voltammograms were recorded. The instrumental and chemical parameters were optimized. The optimized conditions were obtained in pH of 8.4, carbidopa amount of 1.0×10^?6 M, accumulation potential of 0. 0 V, accumulation time of 100 s, scan rate of 100 mV/s and pulse height of 50 mV. The relationship between the peak current versus concentration was linear over the range of 2.4×10^?10–4.8×10^?7 M. The limits of detection were 5.8×10^?11 M and the relative standard deviation at 4.8×10^?10, 2.1×10^?8, and 2.4×10^?7 M of lead ion were obtained 3.2, 2.9, and 2.7%, respectively (n=7).     

Simultaneous Determination of Antimony(III) and Molybdenum(VI) by Adsorptive Stripping Voltammetry Using Quercetin as Complexing Agent

A sensitive and selective voltammetric method for simultaneous determination of Sb(III) and Mo(VI) using Quercetin (Q) as complexing agent is described. Optimal conditions were found to be: pH 3.7, C_Q=6.0 µmol L^?1 and E_acc=?0.10 V. The LOD (3σ) for Sb(III) are 0.076 and 0.040 µg L^?1, whereas for Mo(VI) are 0.086 and 0.048 µg L^?1 with t_acc of 60 and 120 s, respectively. The method was validated using synthetic sea water (ASTM D665) and was applied to the determination of Sb(III) and Mo(VI) in natural waters with satisfactory results.     

阴极溶出伏安法测定异烟肼的研究

报道了吸附阴极溶出伏安法测定异烟肼。探讨了电极反应机理。在０．０１ｍｇｏｌ／Ｌ硼砂底液中，峰电位为－１．４０Ｖ。峰电流与异烟肼浓度在４．０＊１０＾－７－１．５＊１０＾－５ｍｏｌ／Ｌ范围内呈良好的线性关系，相关系为０．９９１３。该方法用于异烟肼片剂的测定，获得满意结果。     

吸附溶出伏安法测定普罗帕酮的研究

在pH 6.47的磷酸盐缓冲溶液中,可得到普罗帕酮的吸附溶出峰。峰电位为-1.38V(vs.Ag/AgCl),富集1min,溶出峰电流与普罗帕酮浓度在8.0x10~(-9)～7.0x10~(-7)mol/L范围内呈线性关系。富集4min检测下限为3.0×10(-10)mol/L。该法用于测定普罗帕酮制剂及人血清中的痕量普罗帕酮,均得到了满意的结果,并探讨了电极反应过程机理。