简易电解池—改换介质—阳极溶出伏安法

采用自制的简易电解池，以圆盘旋转玻碳电极为工作电极，用于阳极溶出伏安法改换溶出介质的可行性研究。以同时测定Ｃｕ（Ⅱ），Ｓｂ（Ⅲ）为例，试验了改换溶出介质的条件。此方法用于矿样中铜和锑的同时测定，结果满意。     

PVC膜修饰粉末微电极溶出伏安法测定水中铅(Ⅱ)

介绍一种ＰＶＣ膜修饰粉末微电有的溶出伏地。该法不需镀汞,不需搅拌,且可在浓度很稀的支持电南中富集。在浓度为０．０２ｍｏｌ／ＬＨＡｃ介质中,进行阳极溶出伏安扫描,有一灵敏Ｐｂ氧化出现,峰电位为－０．４５３Ｖ,溶出峰电流Ｐｂ＾２＋的质量浓度在５．０×１０＾８￣５．０×１０＾－６ｇ／ｍＬ,范围内有很好的线性关系,检出限为２．０×１０＾－８ｇ／ｍＬ。该法应用于逢来水和湖水中微量Ｐｂ＾２＋的直接测定,测定结     

催化动力学分光光度法测定痕量锡(Ⅱ)的研究

在乙酸介质中,痕量α,α‘－联吡啶作催化剂,Ｓｎ＾２＋作活化剂,能灵敏地加速过氧化氢氧化二甲苯胺蓝褪色的指示反应。研究了该反应的最佳条件和动力学参数,建立了一种测定痕量Ｓｎ＾２＋。已用于测定分离钴废液中的Ｓｎ＾２＋。     

α—苯偶酰二肟修饰碳湖电极的制备及对合成水样中铜的测定

报道了α－苯偶酰二肟修饰碳湖电极的制 及对合成水样中铜的测定,在ＰＨ４．１的Ｂ－Ｒ缓冲溶液中通过在－１．２０Ｖ电位下富集Ｃｕ＾２＋后,在－０．２￣＋０．２电位一范围内作阳极溶出伏安法测定。在＋０．０４８Ｖ处有一灵敏的氧化峰,峰电流与Ｃｕ＾２＋浓度在１×１０＾－７￣１×１０＾ｍｏｌ／Ｌ范围内成良好的线性关系,检出限为５×＾－８ｍｏｌ／Ｌ。     

裉色光度法测定SO^2—3的研究

本文研究了ＳＯ＾２－３褪色碱蓝６Ｂ的反应，在ｐＨ５．２Ａｃ－ＮａＡｃ缓冲介质中，ＳＯ＾２－３浓度在０．３９－１２ｍｇ／Ｌ范围内符合比尔定律，仅Ｆｅ＾３＋，Ｎｉ＾２＋，Ｃｒ＾３＋干扰测定，用于食品中ＳＯ＾２－３的测定，结果令人满意。     

痕量亚硝酸根的聚氯乙烯液态膜四氯络铁(Ⅲ)离子电极测定

以新型阴离子载体Ｓ－烷基双硫腙,制备了ＦｅＣｌ＾－４阴离子选择性电极,研究了电极的性能,确定了亚硝酸催化氧化Ｆｅ＾２＋的最佳反应条件,在４ｍｏｌ／Ｌ ＮａＣｌ－０．２ｍｏｌ／Ｌ ＨＣｌ介质中反应５０ｍｉｎ时以尿素终止,反应生成的Ｆｅ（Ⅲ）以ＦｅＣｌ＾－４选择电极电位法测定。间接测定ＮＯ＾－２。线性范围为１５－３５０μｇ／ＬＮＯ＾－２,检出限为８μｇ／Ｌ。该法应用于雪水和水样中亚硝酸根的测定,结果与光度法一致。     

动力学光度法测定痕量铅的研究

在氨水介质中，Ｐｂ＾２＋阻抑过氧化氢氧化偶氮胂Ⅰ褪色的作用，研究了动力学分光光度法测定痕量Ｐｂ＾２＋的新方法。该方法的检出限为４．４×１０＾－１１ｇ／ｍＬ Ｐｂ＾２＋，线性范围为０～１．０μｇ／２５ｍＬ Ｐｂ＾２＋，用以测定人发中的Ｐｂ＾２＋，获得了满意的结果。     

低温凝固高氯酸水溶液体系中固体汞电极性能和铜的氧化还原行为研究

本文介绍凝固电解质体系中固体汞电极的使用特性。在凝固的ＨＣｌＯ４水溶液中，固态汞电极上发生的电化学反应与液态汞和溶液体系中的非常相似。本实验测定了温度降低对Ｃｕ＾２＋的氧化还原过程的影响。最低实验温度达到－１００℃。介质体系的结构变化对于Ｃｕ＾２＋的还原反应和金属互化物有重大影响。     

α-石英表面自由基和离体肺泡巨噬细胞内游离Ca2+、Mg2+浓度的关系

本文用ＡＲ－ＣＭ－ＭＩＣ阳离子测定系统及Ｆｕｒａ－２荧光技术，研究了研磨后表面存在自由基的α－石英，和离体肺泡巨噬细胞作用后细胞内游离Ｃａ＾２＾＋浓度（［Ｃａ＾２＾＋）ｉ）和游离Ｍｇ＾２＾＋浓度（［Ｍｇ＾２＾＋］ｉ的关系。发现在含Ｃａ＾２＾＋和Ｍｇ＾２＾＋的介质中，α－石英表面自由基越多，［Ｃａ＾２＾＋］ｉ和［Ｍｇ＾２＾＋］ｉ升高越大；在无Ｃａ＾２＾＋和Ｍｇ＾２＾＋的介质中，新研磨的α－石英能引起     

遗传算法模拟计算Pb^2＋—FA—SO^2—4体系的化学形态分布

研究了水体中重要污染元素铅在富里酸（ＦＡ），ＳＯ＾２－４共同存在的化学形态分布，根据物料平衡和化学平衡建立了Ｐｂ＾２＋－ＦＡ－ＳＯ＾２－４的化学模型，用Ｐｂ＾２＋滴定络合剂ＦＡ和ＳＯ＾２－４的混合溶液，使用ＡＳＶ测定阳极溶出电流并采用遗传算法（ＧＡ）对铅的化学形态进行了模拟计算，用成对ｔ检验的结果表明，阳极溶出电流的计算值和实测值之间的无显著性差异。     

A flow-through cell for differential pulse anodic stripping voltammetry

A flow-through voltammetric cell with a hanging mercury drop electrode has been developed to fit the static mercury drop electrode (PAR 303). The design has resulted in a linear increase of sensitivity with flow rate and an enhancement of sensitivity by the wall-jet effect. The cell is used in a flow injection system in which samples are introduced with a R??i?ka—Hansen injector. The mercury drop is held at plating potentials while the sample peak passes through the cell. Stripping is done under stopped flow conditions, to reduce noise, after the sample has been washed completely from the cell. The stripping thus takes place into the carrier electrolyte which always has a constant composition independent of sample constituents. Film-forming interfering species will, however, remain on the surface of the mercury drop. The effect of medium exchange on films produced by l-cysteine is reported. The flow-through medium exchange simplifies deaeration, speeds up analysis and reduces contamination.     

用溶出伏安法测定蛋白胨细胞生长液中易变形态铜

采用阳极阶梯溶出伏安法 ,测定了蛋白胨细胞生长液中的易变形态铜 ,并获得了总铜量中易变形态的摩尔分数以及易变形态的表观稳定常数。通过使用交换介质法 ,较好消除了由于蛋白胨细胞生长液中各种氨基酸或其它组分吸附在汞膜表面而引起的干扰     

电沉积制备钯铂电极上乙醇的电催化氧化

研究了乙醇在碱性介质（１．０ｍｏｌ·Ｌ－１ＮａＯＨ）中电沉积制备的Ｐｄ／ＧＣ、Ｐｔ／ＧＣ和Ｐｄ．Ｐｔ／ＧＣ电极上的电催化氧化．实验结果表明：由此法制备的钯铂系列合金电极对乙醇的电催化氧化表现出明显的协同效应─—乙醇在含把原子分数ｙｐｂ＝０．３３６的Ｐｄ－Ｐｔ／ＧＣ合金电极上的阳极交换电流密度是其在纯铂电极上的３０多倍．     

电沉积制备钯铂电极上乙醇的电催化氧化

研究了乙醇在碱性介质（１．０ｍｏｌ．Ｌ＾－１ＮａＯＨ）中电沉积制备的Ｐｂ／ＧＣ、Ｐｔ／ＧＣ和Ｐｄ－ｐｔ／ＧＣ电极上的电催化氧化,实验结果表明：由此法制备的钯铂系列合金电极对乙醇的电催化氧化表现出明显的协同效应－乙醇的含钯原子分数ｙｐｄ＝０．３３６的ｐｄ－ｐｔ／ＧＣ合金电极上的节极交换电流密度是其在纯铂电极上的３０多倍。     

Experimental and computational study of species formed during electrochemical stripping oxidation of copper in chloride media determination of copper(II) in the ng l(-1) range by stripping potentiometry

A novel glassy carbon electrode design, permitting medium exchange in batch mode without loss of electrode potential control, has been used for the study of copper(I) and copper(II) species formed during constant current stripping oxidation of copper in chloride media. It was found that copper(II) species dominated at chloride concentrations below about 1 mM and that soluble copper(I) species dominated at chloride concentrations above about 100 mM. In the concentration range 1-100 mM, soluble copper(I) and copper(II) species are formed as well as solid copper(I) chloride, the latter giving rise to a split peak as it is further oxidised to copper(II). The experimental results agreed satisfactorily with computer calculated equilibria data using the haltafall program. The medium exchange procedure has, furthermore, been used for the determination of copper(II) in seawater reference samples, 7.5 M ammonium acetate/2.5 M acetic acid being used as stripping medium. The detection limit, after 15 min of electrolysis, was found to be 6 ng l(-1) (0.10 mM) and the relative precision 6-10%.     

Adsorptive stripping behaviour of mitoxantrone on carbon paste electrodes

The electrooxidation of mitoxantrone (MXT) on carbon paste electrodes was studied using voltammetric techniques in adsorption conditions. The analyte was accumulated at the working electrode (a carbon paste electrode) under precisely controlled mass-transport conditions and stripped electrochemically in the same solution. An electrode pretreatment is proposed which shows good reproducibility of the analytical signal (0.81%). The stripping step was studied with alternating current voltammetry providing a linear response in the concentration range 5 x 10(-11) to 7 x 10(-10)M in aqueous samples. Finally, a method using the medium exchange and AC phase-selective adsorptive stripping voltammetry technique was proposed for MXT analysis in urine samples.     

不同电极材料和不同酸介质对3-甲基吡啶电氧化的影响

在以质子交换膜为隔膜的电解池内,通过3-甲基吡啶在PbO₂/Ti、SnO₂/Ti、石墨和MnO₂/Ti电极上的电氧化研究发现,在硫酸溶液中,PbO₂电极是催化活性最高的工作电极.通过3-甲基吡啶在硫酸、高氯酸、磷酸和乙酸介质中的电氧化研究发现,对于PbO₂电极,硫酸是最适合的介质.利用循环伏安实验和恒电位电解实验,研究了电氧化条件和电催化活性,比较了各种条件下的电流效率和选择性.     

Thallium Determination at the Single Picomole per Liter Level by Flow‐Injection Differential‐Pulse Anodic Stripping Voltammetry

The flow‐injection differential‐pulse anodic stripping voltammetric (FI‐DP‐ASV) procedure has been developed for the determination of thallium concentration of the order of the single pM. Due to the analyte preconcentration at the electrode, DPASV is among the leaders in competition for achieving a detection limit as low as possible. The enrichment factor can be easily regulated by the duration of the preconcentration time. A DPASV measurement in a flow‐injection system enables the circulation of an analyzed sample and a medium exchange when preconcentration is completed. This approach ensures significant improvement of a background current. The measurements were performed in a cell of the wall‐jet type containing the mercury film electrode. One hour preconcentration was used for the determination of the lowest thallium concentrations. The developed method provides the opportunity to determine thallium in real environmental samples at the single pM level with the detection limit equal to 0.25 pM and RSD equal to 8.2%. This is by more than one order of magnitude better than the lowest detection limit reported in the literature (5 pM). Additionally, the medium exchange resulted in the improvement of the measuring accuracy, which was evidenced by the application of a certified reference material.     

Electrocatalytic oxidation of methanol on a glassy carbon modified electrode by bis(1,2-phenylenediamine) nickel(II) complex

Electrocatalytic oxidation of methanol on a glassy carbon electrode coated with Ni(II)-(1,2-phenylendiamine)₂ (GC/NiOPD), conditioned by the potential recycling in a potential range of 100–650 mV (vs. SCE) is studied by cyclic voltammetry in an alkaline medium (0.10 M NaOH). The results show that the NiOPD layer formed at the surface of the electrode behaves as an efficient electrocatalyst for the oxidation of methanol in the alkaline medium via the Ni(III) species with a cross exchange reaction occurring throughout the layer at a low concentration of methanol. The effects of various parameters such as potential scan rates, methanol concentration and NiOPD surface concentration on the electro-oxidation of methanol are also investigated.     

Electrocatalytic Oxidation of Methanol on a Nickel‐Porphyrin IX Complex Modified Glassy Carbon Electrode in Alkaline Medium

Electrocatalytic oxidation of methanol on a glassy carbon disc electrode modified with Ni(II)‐hematoporphyrin IX, complex and conditioned by potential recycling in a limited range (between 100 and 600 mV vs. SCE) in 0.10 M NaOH solution, abbreviated as NiOHPME(A), was studied by cyclic voltammetry in alkaline medium. The results were compared with those obtained for a NiO modified glassy carbon electrode, NiOME, prepared in similar conditions. The findings show that the NiOHP film at NiOHPME(A) behaves as an efficient electrocatalyst for the oxidation of methanol in alkaline medium via Ni(III) species with the cross‐exchange reaction occurring throughout the layer at a low concentration of methanol and for a thin film of modifier. A plausible mechanism was proposed for catalytic oxidation of methanol at NiOHP modified electrode. Moreover, the effects of various parameters such as the scan rate, methanol concentration, thickness of NiOHP film and the real surface area of modified electrode on the oxidation of methanol were investigated. Finally, it has been shown that the NiOHPME(A) has a long‐term stability toward the oxidation of methanol.