Chemistry

Quantum Chemical Studies of Potential Associates in Europium (III) Alginate Solutions

Metal-alginate complexes (especially, lanthanide gels) are particularly interesting for medical and biological analysis due to their luminescent properties upon UV light excitation. Unfortunately, synthesis and further physical and chemical studies of such complexes is inhibited by their high cost. However, this problem can be solved by using quantum chemical methods to predict potential properties of lanthanide alginates based on the results of their geometry optimization and electronic structure calculation.

The Solid-state and Planar Sensors for the Determination of Cefotaxime in Aqueous and Biological Fluids

Cefotaxime is a cefalosporin antibiotic possessing a high efficiency at curing severe bacterial infections. For the determination of cephalosporin antibiotics in different objects, spectroscopic, chromatographic, electrochemical methods, immunoassay, etc. are used, which demand for expensive devices and organic solvents. Potentiometric sensors let one expressively detect cefalosporin antibiotics in small samples without previous sample preparation.

Sensor Plate in Horseradish Peroxidase Determination Based on Oxidation of Triphenylamine-4-sulphonic Acid by Hydrogene Peroxide

The oxidation of triphenylamine-4-sulphonic acid (TPASA) by hydrogen peroxide in presence of horseradish peroxidase (HRP) in weak acid medium and after incorporation of TPASA in polymeric hydrogel matrix of polyurethane (type D4) was investigated by spectrophotometry. The stability of TPASA product enzymatic oxidation under variation of reaction condition (reagents concentration, acidity) was studied. The optimum condition was selected and the possibility of HRP detection in sensor plate was shown with limit of detection 0.3•10-4 U/mL.

Multicomponent Reaction 3,4-dihydronaphthalene-1(2H)-one with N-Nucleophiles

Studied «one-pot» reaction of 3,4-dihydronaphthalene-1 (2H)-one with aromatic aldehydes and (thio)urea in conditions of modified Biginelli reaction under thermal and microwave exposure. Showed a reduction reaction time and increasing the yield of the desired products benzohinazolinonsderivatives with microwave activation starting compounds.

Light Influence on Morphogenesis Wheat

In work results of research morphogenesis wheat are presented at presence or absence of the light factor. Influence of light on growth of all leaf shoot, activity of a cone of increase and growth of germinal root system of a seedling of wheat is established. In the presence of the light factor growth epicotyl begins with the moment of the termination of growth coleoptile. Growth epicotyl occurs synchronously to growth of a sheath of 1st leaf. In the absence of light growth coleoptile and epicotyl proceeds and after end of growth of a plate and a sheath of 1st leaf.

Thermodynamic Analysis of Transformation Isomerization Reaction of n-Hexane on Zeolite Systems ZSM-5, Cr-Bi-ZSM-5

A comparative analysis of dependencies isomerization reaction, and the formation reaction of isobutane, isopentane in the temperature range from 573 to 673 K at the high-silicon ZSM-5 system and the same system modified with oxides of bismuth, and chromium.

Spatial and Electronic Structure of the Pyrene Molecule, Tripaflavin Cation and Eosin Anions As a Prerequisite for Interpreting Their Solid-phase Fluorescence

At the B3LYP/6-311++G(d,p) level of theory, involving the NBO analysis, the spatial and electronic structure of the pyrene molecule, tripaflavin cation, eosin monoanion and dianion has been computed. The results obtained will offer a framework for interpreting the peculiarities of the above species solid-phase fluorescence.

Glaukonit’s Influence on Viability and Development Seeds of Some Grain Crops

It is defined macro- and microelement composition of glaukonite ore of the Beloozersky field of the Saratov region. It is established that it contains a set macro- and the minerals necessary for a mineral delivery of plants. The possibility of application of the studied glaukonite as tools for processing of seeds of grain seeding before crops, on the example of seeds of wheat and rye is considered. Effectiveness of processing of seeds of Marusenka rye and spring-sown Favourite weak field is studied by aqueous extracts of a glaukonite of various concentration (0,01; 0,1 and 1%).

Electrostatic and Hydrophobic Interactions in the System: Synthetic Food Dye Е133 – Cetylpyridinium Chloride – H2O

Investigated the conditions of formation and solubilization ion associate synthetic food dye «brilliant blue» (Е133) ions with cetylpyridinium chloride (TSPKH). The composition of the associate, the solubility in water and micelles TSPKH. The importance of such interactions in the photometric, potentiometric and other methods of determination of synthetic food dyes.

Application of Solid-surface Luminescence for Determination Indicator Coefficients of Polycyclic Aromatic Hydrocarbons

Luminescence of PAH (anthracene, phenanthrene, pyrene, fluoranthene, benzo(a)anthracene, chrysene, benzo(a)pyrene) in aqueous media and in the solid phase of cellulose diacetate is investigated. It is established that solid surface luminescence (SSL) analysis increases the detection sensitivity of PAH in water without extraction and preconcentration with organic solvents, an exception is chrysene. The spectral characteristics show SSL-method to be using for detection of indicator isomers pairs of PAH.

Pages