玻碳电极吸附伏安法测定痕量硫化物的研究

研究了利用玻碳电极吸附伏安法测定痕量硫化物的新方法。在含高铁离子的酸性溶液中,硫化物与对-氨基苯二甲基盐酸盐(p-ADAD)反应生成亚甲基蓝,采用线性扫描伏安法亚甲基蓝于-0.30 V(vs.SCE)在玻碳电极上出现灵敏的还原峰,峰电流与S2-浓度在0～25μg/mL范围内呈良好的线性关系。优化了实验条件,研究了电极反应机理。该方法具有灵敏、简便、快速、避免汞污染等特点。已成功用于多种水样中痕量硫化物的测定,回收率为98.0%～104.6%,结果令人满意。     

Electrochemical Sample Preparation for the Voltammetric Determination of Heavy-Metal Ions in Wine

An original, simple, and rapid method consuming little labor and eliminating the contamination of a sample and the loss of analytes is proposed for the electrochemical preparation of wine samples. The time of electrochemical sample preparation (ECSP) is no longer than 10 min. A four-electrode single-compartment electrolyzer allows all stages of voltammetric analysis (electrochemical sample preparation, electrochemical preconcentration and determination) to be carried out continuously. The processes occurring at electrodes at different stages of analysis are described. The concentrations of heavy metals determined in wines by stripping voltammetry (SVA) and atomic absorption spectroscopy (AAS) are compared.     

Thin-Layer Chromatographic Image Analysis for the Determination of Sulfide Ions Using Pyrylium Cations

JPC – Journal of Planar Chromatography – Modern TLC - A highly specific and sensitive chromatographic method for the determination of sulfide ions was developed. The procedure is based...     

吡柔比星在羧基离子注入氧化铟电极上的电化学还原及其测定

采用离子注入技术将羧基离子注入到氧化铟锡(ITO)表面,制备了羧基离子注入氧化铟锡电极(COOH/ITO).电极表面羧基的引入用X射线光电子能谱(XPS)进行表征.此电极被应用到了吡柔比星的电化学行为的研究及其测定当中.在COOH/ITO电极上,吡柔比星在5 nmmol/L磷酸盐缓冲溶液(pH 7.2)中,出现还原峰,...     

Voltammetric Method for Determining Ferric Ions with Quercetin

A novel, simple, rapid, inexpensive, highly sensitive voltammetric method developed for determining ferric ions with quercetin in water samples and iron supplements using a disposable bare pencil graphite electrode is described. The limit of detection and analytical ranges for the ferric ions were 3.6 nM and 17.9–716.0 nM, respectively. The results with the water samples were compared with those obtained from a potentiometric auto-titration system, and the method's accuracy was tested using certified reference material. The complex stoichiometry and electrode reaction were also systematically investigated with UV-visible spectrophotometry, ¹H-NMR spectroscopy and voltammetry.     

Bismuth Nanoparticles in Stripping Voltammetry of Sulfide Ions

For the first time, carbon screen‐printed electrodes (CSPE) modified with bismuth nanoparticles have been used to determine sulfide ions with stripping voltammetry (SV) by formation of sparingly soluble compounds with the electrode material. The impact of weight, degree of bismuth dispersion on CSPE surface, and Bi₂S₃ accumulation parameters on the sensitivity of the sensor have been studied. It has been established that bismuth nanoparticles (Bi_nano) as agglomerates of about 180 nm exhibit the optimum sensory properties. The linear concentration range has been observed over the interval of 0.93–5 µM sulfide ions during the accumulation time of 75 s. A detection limit of 0.15 µM sulfide ions was achieved.     

Voltammetric Determination of Rubeanic Acid

Procedures for the voltammetric determination of rubeanic acid (RA) at a mercury-film electrode were proposed. They are based on the oxidation of RA at –0.70 to –0.80 V or on the reduction of mercury sulfide, the product of RA oxidation, at –0.82 to –0.85 V (versus a saturated silver–silver chloride electrode) in a 1 M NaOH solution. The oxidation and reduction currents are linear functions of RA concentration in the ranges from 9 × 10^–6 to 3 × 10^–4 M and from 5 × 10^–6 to 3 × 10^–4 M, respectively.     

Stripping Voltammetric Determination of Mezapam

It was shown that mezapam can be determined by cathodic stripping voltammetry in aqueous media. At a potential sweep rate of 50 mV/s, pH 2.5, amplitude of polarizing voltage of 50 mV, initial accumulation potential of –0.75 V, and accumulation time of 1 min, the detection limit for mezapam was found to be 0.1 g.     

Renewable Drops Electrochemical Sensor for Sulfide Ions Detection

The design and characteristics of a novel electrochemical system, which uses a drop as a renewable electroanalytical sensor, are described. This article describes the performance of the electrochemical system, the coupling of the experimental arrangement with flow injection technique and a demonstration of its applicability for the measurement of sulfide. The method is based on renewable drops of ferricyanide ions, buffered by borate. The ferrocyanide ions, product of the reaction between ferricyanide and sulfide ions, are oxidized on a platinum microelectrode and the current measured is related to sulfide concentration. The measurements can be done in continuous or static flow mode. In continuous mode, the detection limit is 5.0×10^?5 mol L^?1.     

Voltammetric Investigation and Determination of Mefloquine

The electrochemical reduction behavior of mefloquine HCl (MEF), the antimalarial drug, was studied in aqueous alcoholic media at a hanging mercury drop electrode. Cyclic voltammetric studies showed one well‐defined reduction peak and one ill‐defined reduction wave between pH 1.5 and 12.03. The reduction was found as irreversible or quasireversible depending on pH and exhibited diffusion controlled process. The mechanism of reduction process was discussed. A systematic study of the experimental parameters that affect the differential pulse and square wave response was carried out and the optimized experimental conditions were obtained. The calibration plots were derived for the determination of MEF in pharmaceutical dosage forms and biological samples. DPV and SWV techniques for the determination of MEF in Britton–Robinson buffer at pH 11.10, which allows quantitation over the 6×10^?6 to 8×10^?5 M range in the supporting electrolyte, were proposed. The linear response was obtained in samples in the ranges of 6×10^?6 to 6×10^?5 M for both techniques. These methods are fully validated. The standard addition method was used in the biological media. No electroactive interferences from the excipients and endogenous substances were found in tablets and biological fluids.     

Voltammetric Determination of Aflatoxin B1

For the first time the possibility of voltammetry used for the determination of aflatoxin B1 on a glassy carbon electrode was shown. The effect of pH of a supporting electrolyte on the analytical signal of aflatoxin B1 has been investigated and it was shown that there is a more pronounced peak with a maximum current at pH of 5.33. The most favorable supporting electrolyte for a linear range of detectable concentrations of aflatoxin B1 – 0.1 M (NH₄)₂SO₄ was determined. The results of research on the development of conditions of voltammetric measurement of aflatoxin B1 are presented.     

Voltammetric Ultra Trace Determination of Tellurium

Abstract

A simple and convenient method is described for the determination of low concentration tellurium based on differential pulse polarographic reduction of Te(IV) in alkaline medium. Linearity of the calibration curve was achieved up to 25.5 ppm with a limit of determination of 0.02 µg/mL. The possible interference of coexisting metal ions was examined and ruled out. The method has been successfully applied for the analysis of tellurium in industrial waste samples.     

伏安法测定化妆品中熊果苷

采用线性扫描伏安法、循环伏安法和微分脉冲伏安法等方法研究了熊果苷在玻碳电极上的电化学行为.试验结果表明:pH 2.0的B-R缓冲溶液中,熊果苷在0.86 V(vs.SCE)处有一灵敏的氧化峰,在0 V有一较小的还原峰.以氧化峰为考察对象,对试验条件进行了优化.在最佳条件下,熊果苷浓度在2.0×10-7～4.0×10-6mol·L-1范围内与氧化峰电流呈线性关系,检出限为1.4×10-7mol·L-1.该方法用于膏霜类模拟化妆品中熊果苷的检测,得到的回收率在98.0%～100.6%之间.     

硫化物的快速分光光度法测定

提出了测定微量硫化物的快速亚甲蓝分光光度法，实验结果表明，在硫酸溶液中，Ｋ２Ｃｒ２Ｏ７＋对二甲氨基苯胺＋Ｓ＾－２迅速显色反应形成亚甲蓝，表现摩尔吸收系数为４．０６×１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１；最大吸收波长为６６４ｎｍ；线性范围为０～０．８ｍｇ／Ｌ，实验了采用全差示光度法直接测定水中硫化物的条件，用于某江水中２１．６μｇ／Ｌ硫化物测定时，相对标准偏差为３．２％（ｎ＝６）；试样的标准加入回收     

微分伏安法测定微量碘

采用过量联合氧化剂高锰酸钾-次氯酸钠氧化试液中碘至IO3-,剩余的高锰酸钾和次氯酸钠用过量的亚硫酸钠反应除去,利用IO3-的电活性,建立了在四硼酸钠-吐温-80底液中的线性扫描伏安法测定微量碘的方法.优化了试验条件,研究了伏安特性.在最佳试验条件下,一阶导数峰电流与碘质量浓度在0～16 μg·L-1叫范围内呈线性关系(r=0.996 4),检出限为0.6 μg·L-1.对共存离子作了干扰试验,表明方法的抗干扰能力较强,用于食品中微量碘的测定结果的相对标准偏差(n=6)值均小于0.9%,加标回收率在97.8%至99.2%之间.     

Voltammetric Sensor for Total Cholesterol Determination

We report on a voltammetric sensor for the detection of total cholesterol. The sensor was fabricated by co-immobilization of two enzymes: cholesterol oxidase (ChOx) and horseradish peroxidase (HRP) on porous graphite. The electrochemical behavior of the sensor was studied with the use of linear sweep voltammetry. It has been shown that the sensor has high stability and high sensitivity (16 μA mM⁻¹ cm⁻²). The biosensor exhibited a wide linear range up to 300 mol/dm³ in a condition close to physiological (pH=6.86). Besides, the interferences of some key analytes containing in the blood were studied. As a matter of fact, making a fabricated sensor is rather promising for using in clinical practice.     

Express Voltammetric Control of Permanganate Ions in Process Solutions from Zinc Production

Express voltammetric analysis of zinc sulfate solutions for manganese(VII) ions was developed. The influence of the components of the supporting electrolyte on the measurement sensitivity and selectivity was studied. The method is intended for automated control of the permanganate treatment of the zinc electrolyte to remove cobalt(II) ions.     

微分脉冲溶出伏安法测定除草通

提出了苹果、土豆、西红柿中除草通残留量的电分析化学测定方法,研究了除草通在汞电极上的电化学行为,探讨了其电极反应机理。结果表明,除草通在汞电极上具有吸附性质,其电极反应为不可逆的还原过程。本方法的测量线性范围为0．01～0．16mg/L,检出限为9．1μg/L.