Electrochemical Sensors for the Simultaneous Detection of Phenolic Antioxidants

Journal of Analytical Chemistry - Electrochemical sensors for the simultaneous determination of natural or synthetic phenolic antioxidants, their analytical characteristics, advantages, and...     

Term “nano” in electroanalysis: A trendy prefix or a new stage of its development?

The use of term “nano” in electroanalytical methods (electroanalysis) is considered. Attention is paid to the recent trend in the development of electroanalysis in context of modern views on processes in the double electric layer, or interface, as a nanosize structure in an electrochemical nanoreactor determining the nature of the analytical signal. It is shown that the creation of new methods of chemical analysis of usual objects using nanostructures, nanosystems, and nanomaterials immobilized in an electrochemical interface has favored the development of nanoelectroanalytics. The use of terms with the prefix nano- in electroanalysis and some nanotechnologies is considered. It was noticed that the nomenclature in the nanofield has not been established yet. Not only the available terms should be refined and formulated, but also those that have not been adequately translated into Russian. With the application of nanotechnologies, electroanalysis follows the world trend in the choice of priority objects of analysis.     

Voltammetric and flow-injection determination of carbohydrates using composite electrodes based on carbon nanotubes and Nickel(II) hexacyanoferrate

The catalytic activities of oxo and hydroxo forms of nickel(II) on the surface of a nickel deposit and an inorganic film of nickel(II) hexacyanoferrate(III) (NiHCF) electrodeposited on a glassy-carbon electrode both unmodified and modified by multi-wall or single-wall (also functionalized) carbon nanotubes in the electrooxidation of glucose, sucrose, and maltose are compared. A more pronounced catalytic effect was obtained in the electrooxidation of these carbohydrates on an electrode modified with functionalized singlewall carbon nanotubes and a NiHCF film. Methods are proposed for the voltammetric and flow-injection determination of carbohydrates on this composite electrode. A linear dependence of the analytical signal on the analyte concentration was observed in the range from 5 × 10^?7 to 5 × 10^?2 M under stationary conditions and from 0.003 to 0.3 μmol under flow conditions.     

Inversion-Voltammetric Determination of Heavy Metal Ions on Electrodes Modified with Mono- and bis-N-Thiophosphoryl Thiourea

A method is proposed for determining Ni^{2 +}, Co^{2 +}, Cu^{2 +}, Cd^{2 +}, and Pb^{2 +} ions by inversion voltammetry on carbon-paste electrodes modified with N-diisopropoxythiophosphoryl-N'-phenyl thiourea and its derivatives: N,N'-bis-(diisopropoxythiophosphorylamidothiocarbonyl)-1,5-diamino-3-oxapentane, N,N'-bis- (diisopropoxythiophosphorylamidothiocarbonyl)-1,8-diamino-3,6-dioxaoctane and N,N'-bis-(diisopropoxythio- phosphorylaminothiocarbonyl)-1,10-diaza-18-crown-6.     

Electrocatalytic Oxidation of Ethanol on Graphite Electrodes Coated with a Nafion Film with Incorporated Particles of Ruthenium or Its Complexes

The electrochemical behavior of ethanol on graphite electrodes with a Nafion film containing ruthenium as a crystalline metal deposit or a metal complex was compared. It was found that, in the oxidation of ethanol, aqua and phenanthroline complexes of ruthenium(III) incorporated in the Nafion film exhibit catalytic activity. A larger catalytic effect was observed at an electrode containing the Ru(phen) ₃ ³⁺ complex. A procedure is proposed for the voltammetric determination of ethanol at this electrode.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 6, 2005, pp. 603–609.Original Russian Text Copyright © 2005 by Shaidarova, Gedmina, Chelnokova, Budnikov.Presented at the VI All-Russian Conference (with International Participation) on Electrochemical Methods of Analysis (EMA-2004, Ufa, May 23–27, 2004).     

Cholinesterase Sensors Based on Thick-Film Graphite Electrodes for the Flow-Injection Determination of Organophosphorus Pesticides

Flow cholinesterase sensors based on planar thick-film graphite electrodes and immobilized preparations of acetyl- and butyrylcholinesterase with various activities were developed. Analytical parameters of the determination of organophosphorus pesticides depend on hydrophilic–hydrophobic interactions at the membrane–solution interface. When passing from the steady-state to flow-injection conditions of signal measurements, the limits of detection of coumaphos and chlorpyrifos-methyl decrease by a factor of 5–8, while the limit of detection of hydrophilic trichlorfon increases by a factor of 3–4. The cholinesterase sensors developed in his work can measure the concentrations of pesticides in a continuous mode for 8–12 h with the throughput of up to 5–6 measurements per hour.     

Single crystalline YAG:Ce phosphor for powerful solid-state sources of white light. The influence of production conditions on luminescence properties and lighting characteristics

It is shown that the spectral properties and spatial distribution of LED radiation with a YAG:Ce single crystalline luminescent converter significantly depend on the morphology of the converter surface. The variation of surface roughness enables one to obtain a light source with a wide range of color characteristics. As a result of optimization of converter parameters we demonstrate a possibility of creating a white light LED with correlated color temperature Т_CC ~ 5000–6500 K and color rendering index CRI ≈ 60–70.