超微粒子合成方法的发展动向

超微粒子是指粒径比光波还要短(100um以下),而性质介于本体物质和原子之间的物质。近年来,由于超微粒子在磁性、催化、烧结、光学等方面显示出独特性能,作为一类新型材料在许多领域中将得到广泛应用。国外已组织大批物理、化学工作者从事研究,使超微粒子的合成和机理探讨成为十分活跃的研究领域。本文对超微粒子合成方法的发展动向和应用作简     

紫外速率法的误差分析

对紫餐速率法的误差来源作了实验分析,并在此基础上提出了相应的控制措施,以保证紫外速率法及自动仪测定的准确性.     

磺胺二甲嘧啶的极谱伏安行为

本文考察了磺胺二甲嘧啶在多种底液中的极谱伏安行为，发现其在ＢｒｉｔｏｎＲｏｂｉｎｓｏｎ（ＢＲ）缓冲溶液（ｐＨ２．２）中产生一个良好的还原峰，峰电位为－０．８５Ｖ（ｖｓ．ＳＣＥ），峰电流与磺胺二甲嘧啶浓度在１×１０－７３×１０－４ｍｏｌ／Ｌ范围内呈良好的线性关系，检出限为９×１０－８ｍｏｌ／Ｌ，大多数金属离子和无机阴离子不干扰测定，可望用于定量测定用多种电化学方法研究了该还原峰电流的性质，结果表明，它是具有吸附性质的不可逆还原峰     

改进示波计时电位法

本文克服了dE/dt～E曲线线性范围窄、分辨率差等缺点,把dE/dt～E曲线的切口变成峰形,具有再现性好、线性范围宽、灵敏度高、分辨率好等优点.采用内标法和频谱分析进行了定量测试工作,取得了满意的结果.     

聚烯烃的化学接枝改性

综述了化学接枝改性聚烯烃的三种方法,即溶液法,熔融法及固定相法,并讨论了接枝单体的选择,接枝机理和接枝物的性能表征。     

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     

椭圆法测量接触角

接触角在胶体与表面化学、矿物浮选、洗涤和油气开采等领域是一项重要的物性参数.本文提出椭圆法计算接触角的公式,在接触角小于90°时,利用测量出的椭圆的长轴和短轴半径和油-水-固接触点的坐标计算接触角;在接触角大于90°时,只需在椭圆轮廓线上选择两点,测量四个数据计算接触角,该方法计算公式比较简单,便于推广应用.本文提出将...     

Electrochemical determination of paraquat using a DNA-modified carbon ionic liquid electrode

Deoxyribonucleic acid (DNA) was electrochemically deposited on a carbon ionic liquid electrode to give a biosensor with excellent redox activity towards paraquat as shown by cyclic voltammetry and differential pulse voltammetry. Experimental conditions were optimized with respect to sensing paraquat by varying the electrochemical parameters, solution pH, and accumulation time of DNA. Under the optimized conditions, a linear relation exists between the reduction peak current and the concentration of paraquat in the range from 5?×?10^?8 mol L^?1 to 7?×?10^?5 mol L^?1, with a detection limit of 3.6?×?10^?9 mol L^?1. The utility of the method is illustrated by successful analysis of paraquat in spiked real water samples.

Conducting Polymer/Ionic Liquid Composite Modified Carbon Paste Electrode for the Determination of Carbaryl in Real Samples

A new method has been described for carbaryl determination using a simple electrochemical sensor. The unique properties of poly‐pPhenylenediamine and ionic liquid were exploited to fabricate carbon paste electrode modified with composite based on conducting polymer/ionic liquid. Electrode surface characterization was performed by electrochemical methods (cyclic voltammetry and electrochemical impedance spectroscopy) and by scanning electron microscopy. Differential pulse voltammetry was employed for the detection of carbaryl in acetate buffer solution. Different parameters affecting the carbaryl response were optimized such as ionic liquid amounts, cycle number of polymerization and monomer concentration, pH, and accumulation time. Under the optimum experimental conditions, a linear response was obtained between 0.5 and 200 μmol/L, with detection limit of 0.09 μmol/L. The developed sensor offered satisfactory results for carbaryl detection in spring water and fruit samples.     

香豆素在离子液体(BMIMBF4)中的电还原行

室温离子液体由大的有机阳离子(咪唑、吡啶、季铵和季等)和各种各样的阴离子[AlCl-4, PF-6, BF-4, CF3SO-3, (CF3SO3)2N-等]组成, 是一种新型的溶剂, 具有稳定性好、蒸气压小、毒性小和不易燃等优异的物理化学性质, 已引起了人们的广泛关注. 因而在这种新型溶剂中进行有机物电化学行为的研究, 用于评价其作为“绿色”电化学或新型电化学反应的可行性很有必要.     

Chemical capacitance of nanoporous-nanocrystalline TiO2 in a room temperature ionic liquid

The electrochemical behaviour of nanoporous TiO(2) in a room temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide (EMITFSI), was investigated by cyclic voltammetry (CV) and impedance spectroscopy. Exponentially rising currents in voltammetry were attributed to the charging/discharging of electrons in the TiO(2) film and a charge transfer mechanism. The main features of the voltammetry and impedance followed the same trends in the ionic liquid as in other organic solvents and also in aqueous electrolytes. In the presence of lithium ions, the onset potential of the charge accumulation increased due to the change of the initial position of the TiO(2) conduction band. The results show that substitution of organic solvents contained in solar cells, supercapacitors or other electrochemical devices is in general feasible, though requires some adjustment in the electrolyte composition for optimal performance.     

Determination of N-nitrosamines by high-performance liquid chromatographic separation with voltammetric detection

The highly polar, nonvolatile N-nitrosamines, N-nitrosoproline and N-nitrosodiethanolamine, are determined by high-performance liquid Chromatographic separation with electrochemical detection using d.c. voltammetry, normal pulse voltammetry, and differential pulse voltammetry. The influence of flow rate and pulse time are determined, and detection limits on the order of 10^-7 M are obtained.     

芦丁在离子液体[bmim]BF4中的电化学行为及其影响因素

采用线性扫描伏安法和循环伏安法研究了芦丁在亲水性离子液体1-丁基-3-甲基四氟硼酸盐([bmim]BF4)中的电化学行为, 讨论了扫描速度、富集时间及温度等因素对其电化学行为的影响. 结果表明, 芦丁在[bmim]BF4中的电极过程是一个受吸附控制的准可逆过程, 电子转移数为2, 标准速率常数ks=0.126 s-1. 同时, 分别考察了水及乙醇对芦丁氧化还原特性的影响, 结果发现, 随着水或乙醇含量的增加, 芦丁的峰电位负移, 峰电流增加, 且水的影响比乙醇的影响明显. 在离子液体-水体系中, 芦丁的峰电流与浓度在4.0×10-5～1.4×10-4 mol/L范围内呈良好的线性关系, 检出限为1.0×10-5 mol/L, 有望用于芦丁含量的分析测定.     

稀土在氯化物熔盐中液体铝阴极上的去极化作用

利用液体阴极从熔盐中电解制备稀土合金,由于液体阴极上的会极化作用,比在固体阴极上析出要容易的多,电流效率也高得多,成为很有意义的工艺方法。     

Kinetics of anodic oxidation of copper in an ionic liquid composed of 1-butyl-3-methyl imidazolium bromide monohydrate

Cyclic voltammetry, chronopotentiometry, and gravimetry were used to study the electrochemical oxidation of copper in an ionic liquid, 1-butyl-3-methyl imidazolium bromide monohydrate.     

Heterogeneous electron transfer kinetics at the ionic liquid/metal interface studied using cyclic voltammetry and scanning electrochemical microscopy

The electrochemical behavior of a redox-active, ferrocene-modified ionic liquid (1-ferrocenylmethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) in acetonitrile and in an ionic liquid electrolyte (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) is reported. Reversible electrochemical behavior was observed in each electrolyte with responses typical of those for unmodified ferrocene observed in each medium. In the ionic liquid electrolyte, the diffusion coefficient of the redox-active ionic liquid increased by a factor of 5 upon increasing the temperature from 27 to 90 degrees C. The kinetics of electron transfer across the ionic liquid/electrode interface were studied using cyclic voltammetry, and the standard heterogeneous electron transfer rate constant, k (0) was determined to be 4.25 x 10 (-3) cm s (-1). Scanning electrochemical microscopy was then also used to probe the heterogeneous kinetics at the interface between the ionic liquid and the solid electrode and conventional kinetic SECM theory was used to determine k (0). The k (0) value obtained using SECM was higher than that determined using cyclic voltammetry. These results indicate that SECM is a very useful technique for studying electron transfer dynamics in ionic liquids.     

Chitosan/Ionic Liquid Composite Electrode for Electrochemical Monitoring of the Surface‐Confined Interaction Between Mitomycin C and DNA

In the present study a chitosan/ionic liquid modified pencil graphite electrode (CHIT‐IL‐PGEs) was developed for the first time for enhanced electrochemical monitoring of nucleic acid, and the interaction of the anticancer drug Mitomycin C (MC) and calf thymus double stranded DNA (dsDNA) by measuring the oxidation signals of MC and guanine in the same voltammetric scale. Differential pulse voltammetry, cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to evaluate the performance of the CHIT‐IL based biosensor on electrochemical monitoring of DNA, and drug‐DNA interaction. The experimental parameters, IL, dsDNA and MC concentration and the interaction time were then optimized.