Film stripping voltammetry

Film stripping voltammetry is a new electrochemical analytical method consisting in concentrating the test substance in the form of a metal or a sparingly soluble compound on the electrode surface and subsequently recording the current for electrodissolution of the deposit. The method has been worked out for determination of metal ions, anions and variable valence ions, with sensitivities as low as 10(-9)M. As indicator electrodes, solid, usually graphite, electrodes and stationary mercury electrodes are used.     

Surface Microreliefs and Voltage–Current Characteristics of Gold Electrodes and Modified Thick-Film Graphite-Containing Electrodes

The surface microreliefs and voltage–current characteristics of gold electrodes and modified thick-film graphite-containing electrodes were studied. The relationship between the formation of an analytical signal of mercury(II) and the surface microrelief was determined. It was found that the surface of a modified graphite-containing electrode is a self-organizing ensemble of microelectrodes.     

The effect of the system polydispersity on voltammograms of nanoparticles electrooxidation

The paper proposes a mathematical model describing electrooxidation of a polydisperse system of metal nanoparticles from the surface of an indifferent macro-electrode. It is shown that the degree of dispersion of a nanoparticle ensemble affects the shape of oxidation voltammograms. When the degree of dispersion rises and the average size of nanoparticles becomes smaller, the range of oxidation potentials increases. The results of the experimental study of electrooxidation of gold nanoparticles with different degrees of dispersion are given. The particles were localized on the surface of graphite screen-printed electrodes. A good agreement between the parameters of the experimental and calculated voltammograms confirms the correctness of the proposed model.     

Zirconium and hafnium compounds containing various chelate ligands in the molecule

Conclusions A simple general method was proposed for the synthesis of chelate compounds of zirconium and hafnium of the R₄M, R₃MCl, and R₂MCl₂ types by the reaction of-diketones with either the chlorides or the chelate derivatives of the chlorides of Zr and Hf in the presence of an amine. Here members of the previously unknown coordination compounds of zirconium and hafnium were obtained, containing various-diketonic ligands in the molecule.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 689–691, March, 1973.     

Bismuth nanoparticles electrooxidation: theory and experiment

The article presents the findings of microscopic and electrochemical studies of electrooxidation of bismuth particle of varying sizes. Bismuth particles were immobilized on the surface of indifferent carbon containing screen-printed electrodes. The calculations and experimental studies demonstrated that the transition from macroparticles to nanoparticles caused a shift of the maximum current potential of bismuth oxidation into the area with more negative potentials. A positive correlation between experimental and calculated data confirms once again a relevant application of the earlier proposed mathematical model and the possible use of the shift of the maximum current potential of electrooxidation to describe electrochemical activity and energy properties of metal nanoparticles.     

A Mercury-free Electrode for Determining Amalgam-forming Elements by Stripping Voltammetry

A mercury-free modified screen-printed electrode was proposed for the preconcentration and determination of Cu(II), Pb(II), Cd(II), and Zn(II). The simplicity of design, compactness, and low cost of the developed electrode; the possibility of using it as a disposable electrode; and no need in any operations on the mechanical treatment of the electrode surface make this electrode a candidate for portable transducers in flow and discrete analyses.     

Modified solid electrodes for stripping voltammetric determination of tin

The paper describes the determination of tin by ASV using modified thick film electrodes. Three different types of electrodes were developed: One modified with a mixture of Nafion and mercury(II)acetate, one modified with diethyldithiocarbamate (DDC) or pyrrolidinedithiocarbamate (PDC) and mercury(II)acetate, and one modified with calomel. The analyte was accumulated on the electrode surface after special electrochemical pretreatment of the modified electrode. After recording the voltammogram the electrodes were electrochemically regenerated. By virtue of their lifetime and their measurement reproducibility, we preferred the DDC and PDC modified electrodes. They can be used for months without changing their chemical characteristics. The linear range for tin determination with these electrodes is between 1 and 100 μg/L; the detection limit was calculated as 0.9 μg/L. The electrodes were applied to the direct determination of tin in different canned fruit juices without special sample pretreatment. Received: 20 December 1996 / Revised: 11 March 1997 / Accepted: 13 March 1997