Effect of modification on the structure and and mechanical properties of chlorosulfonated polyethylene films

Structure formation in chlorosulfonated polyethylene films is described. Modification with phenol-formaldehyde resin leads to a change in the supermolecular structures, which are stabilized by introducing 1% aluminum diisobutoxymonoacetoacetate into the system. It is shown that modifying the chlorosulfonated polyethylene leads to the formation of stable supermolecular structures and a considerable improvement in the mechanical properties of the films.State Scientific-Research and Planning Institute of the Paint and Varnish Industry, Moscow. Karpov Scientific-Research Physico-Chemical Institute. Riga Polytechnic Institute. Translated from Mekhanika Polimerov, No. 3, pp. 387–390, May–June, 1969.     

Study of complexation between Cu<Superscript>2+</Superscript> ions and <Emphasis Type="Italic">ortho</Emphasis>-azidobenzoic acid

An aqua complex of copper(II) o-azidobenzoate, [Cu(OH)ABA2H₂O]₂ (ABA is o-azidobenzoic acid), was synthesized in an aqueous solution and identified by IR and electronic absorption spectroscopy. In the complex, the azido group is not coordinated by Cu²⁺. When dissolved in dry organic solvents (DMF, DMSO, dioxane, and methanol), the complex undergoes dehydration to give a chelate complex (CC) containing the Cu²⁺-coordinated azido group as a result of the electron density redistribution at its N atoms. The IR spectrum of the chelate complex contains no absorption band at 2135 cm^–1 corresponding to the stretching vibrations of the azido group. The resulting CC is unstable in solutions and spontaneously decomposes with a release of molecular nitrogen. The interaction of a Cu²⁺ ion with o-azidobenzoic acid in dry organic solvents affords a CC similar to the complex obtained on the dissolution of [Cu(OH)ABA2H₂O]₂ in dry solvents.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 195–198.Original Russian Text Copyright © 2005 by Budruev, Karyakina, Levina, Oleinik.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Prussian Blue-Based Thin-Layer Flow-Injection Multibiosensor for Simultaneous Determination of Glucose and Lactate

A planar multibiosensor for the simultaneous determination of glucose and lactate is developed by combining the Prussian Blue-based electrocatalyst and the protocol for immobilization of glucose oxidase and lactate oxidase enzymes from solutions with a high content of an organic solvent. High sensitivity coefficients (>80 mA M^–1 cm^–2 for lactate and >20 mA M ^–1 cm^–2 for glucose) are demonstrated by the multibiosensors operating in the flow-injection mode in a thin-layer measuring cell. The linear range of the analyzed concentration is 1–500 μM for lactate and 5–1000 μM for glucose. A multibiosensor can be used repeatedly (the exhibited operational stability is not less than 100 measurements without the need for recalibration), which allows using it for the analysis of diluted blood samples and blood serum. The electrocatalytic system with a multibiosensor demonstrates performance characteristics that are superior to the commercial analyzers.     

Polyaniline-modified cholinesterase sensor for pesticide determination.

Cholinesterase sensors based on glassy carbon and planar epoxy graphite electrodes modified with processed polyaniline have been developed and examined for pesticide detection. The modification of electrode surface with polyaniline provides high operational stability and sensitivity towards the pesticides investigated. The detection limits found (coumaphos, 0.002, trichlorfon, 0.04, aldicarb, 0.03, methiocarb, 0.08 mg l(-1)) make it possible to detect the pollutants in the waters on the level of limited threshold levels without sample preconcentration.     

Electrosynthesis of poly-o-diaminobenzene on the Prussian Blue modified electrodes for improvement of hydrogen peroxide transducer characteristics.

Electropolymerisation of nonconducting polymer, poly-(1,2-diaminobenzene) on the top of Prussian Blue (PB) modified electrode led to significant improvement of resulting hydrogen peroxide transducer selectivity and operational stability. The reported transducer retained 100% of response during 20 h under the continuous flow of 0.1 mM H(2)O(2), and thus improves the stability level in selective peroxide detection by one order of magnitude. The selectivity value of the PB-poly(1,2-DAB) based H(2)O(2) sensor in relation to ascorbate is approximately 600. No signals to acetaminophen and urate were investigated. PB-poly(1,2-diaminobenzene) modified electrode allows the detection of H(2)O(2) in the flow-injection mode down to 10(-7) M with the sensitivity 0.3 A M(-1) cm(-2), which is only two times lower compared to the uncovered PB based transducer.     

Bioelectrocatalysis by Hydrogenase Th. Roseopersicina Immobilized on Carbon Materials

Application of various carbon materials as substrates for immobilizing hydrogenase and creating a hydrogen enzyme electrode is studied. A stable, highly-active electrocatalyst for mediatorless oxidation–evolution of hydrogen is obtained. The electrocatalyst uses hydrogenase from Th. roseopersicina immobilized on an inactive carbon material (based on carbon cloth TVSh-300M) and retains more than 50% of its initial activity after a half year in storage. An equilibrium hydrogen potential is established on enzyme electrodes made of a graphitized cloth and graphite rods with hydrogenase immobilized on them.     

Non-aqueous enzymology approach for improvement of reagentless mediator-based glucose biosensor

The formation of Nafion membranes containing glucose oxidase and dimethylferrocene as a mediator was optimized using a previously reported non-aqueous enzymology approach for biosensor development. Enzyme immobilization in Nafion membranes was carried out from water-organic mixtures with a high content of organic solvent. The mediator based reagentless glucose electrode was tested in a flow injection system. The response towards glucose addition was stable: the reproducibility during 50 assays exceeded 95%. The response was linear over the glucose concentration range 0.5-50 mM.     

Photolysis of <Emphasis Type="Italic">meta</Emphasis>-azidophenol in water-organic mixtures

Photolysis of m-azidophenol (m-AP) in organic solvents and water-organic mixtures of various composition was studied using the methods of electronic spectroscopy. m-Azidophenol dissolved in water-organic mixtures was shown to form associates with solvent molecules, depending on the composition of the mixture. The nature of m-AP photolysis products and the rate of their formation are determined by the character of m-AP solvation in water-organic mixtures. In acetonitrile solution, a polymeric product is formed via the interaction of the phenol group with the nitrene of an adjacent m-AP molecule. An increase in the mole fraction of water in a water-acetonitrile mixture leads to a decrease in the yield of the polymeric product and an increase in the yield of the hydroxylamine derivative. In water-ethanol mixtures, the hydroxylamine derivative is the main product of photolysis.     

Photolysis of 4,4’-diazidostilbene in a polymeric matrix

The photolysis kinetics of 4,4’-diazidostilbene stereoisomers in a polymeric matrix (polystyrene films) were studied by the techniques of IR and UV spectroscopy, thin-layer chromatography, and spot test analysis, and primary and secondary amines were determined as the photolysis products, their yield being dependent on the type of stereoisomer. It was shown that, in addition to degradation of the azido group and reactions of the produced nitrenes, stereoisomerization (trans-cis) takes place in the photolysis. As a polystyrene film is formed, the cis-stereoisomers converts into the trans-form