Search articles

This is an open access article distributed under the terms of Creative Commons Attribution 4.0 International License (CC-BY 4.0).

Research of Phase Equilibriums in a System of Dibasic Organic Acids: Azelaic, Glutaric and Sebacic

Presented first the results of the research of phase equilibria of threecomponent system azelaic acid – glutaric acid – sebacic acid by used the microcalorimeter heat flow. Identified eutectic composition containing azelaic acid – 33,0 wt %, glutaric acid – 54,0 wt %, sebacic acid – 13,0 wt %. The melting temperature of the alloy eutectic composition in the three-component system is 70,5 °C, the specific enthalpy of melting is 82 ± 10 J./g.

Assessment of the Environmental Safety of Some Building Materials and Products

In recent years, much attention is paid to the environmental safety of industrial materials and products widely used in the construction of residential and public buildings. Housing quality is influenced by the choice of «clean» construction materials not containing any chemical substances harmful to human health, namely: mercury, lead, cadmium, chromium, their salts and isotopes, as well as some naturally occurring radionuclides (radium 226, thorium 232, potassium 40, and cesium 137).

Competitive Binding of K+ in the Presence of Na+ with Bovine Serum Albumin and Hemoglobin

Selective accumulation of monovalent cations K+, Na+, Rb+, Cs+ with albumin and hemoglobin is shown. Preferential sorption of potassium in the presence of sodium with test proteins is determined. It is shown that with increasing concentrations of sodium in the composition of aqueous solutions of the proteins, the amount of potassium bound by proteins increases.

Thermal Isomerization of O-Chlorophenyltetrazolocyclanopyrimidine with Different Structure Types

Temperature dependence of the 1H NMR spectra and TLC data suggest turning the corner isomers of о-сhlorоpheniltetrazolocyclanopyrimidine in the thermodynamically more stable linear forms. The IR spectra were recorded isomeric azide intermediate transformations.

Synthesis of Opto-R-Phenyl Benzimidazoloheksahydroquinazoline with Angular Articulation Rings

Condensation of 2-aminobenzimidazole, ortho-substituted benzaldehydes and cyclohexanone proceeds with the formation of 10-o-Rsubstituted phenyl benz[4,5]imidazolo-6,7,8,9,10,11-hexahydro[1,2-a] quinazolines having angular articulation rings, strukture which is set using IR, NMR, 1 H, 13C spectra.

Fluorimetric Determination of Pefloxacin in Pharmaceutical Preparation

It is shown that pefloxacin forms a terbium complexes in neutral and mildly acidic conditions which are characterized by energy transfer. It is found that the micellar surfactant medium energy transfer efficiency increases. The maximum increase sensitized fluorescence intensity is observed in the presence of SDS micelles. A fluorimetric method for determination of pefloxacin in the drug was developed.

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.

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.

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%).

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.

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.

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.

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.

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.

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.

Increase of Activity Industrial Catalys for Isomerisation Normal Hydrocarbons

Was done the studie of activity zeolite-containing catalyst Cr2О3 +Bi2О3 /ZSM-5 and technical catalyst SI-2, also they combained action in process of conversion of n-hexane at lay-by-layers download. In the process of conversion n-hexane on Cr2О3 +Bi2О3 /ZSM-5 catalyst prevails reaction of cracking and destroy of n-hexane to two symmetric molecule of propane (51,4%). Lay-by-layers download of Cr2О3 +Bi2О3 /ZSM-5 and SI-2 catalysts with high conversion nhexane to achieve a lot of contents iso-hydrocarbons in products of conversion with 200 oC.

Solid-state Potentiometric Sensors for the Determination of Cefuroxime Axetil in Aqueous Media and Oral Fluid

Cefuroxime axetil is a cephalosporin antibiotic of the second generation, it is used in the sequential therapy of patient with sinusitis, community-acquired pneumonia, and other infectious somatic pathologies. For the determination of cephalosporin antibiotics in different objects, spectroscopic, chromatographic, electrochemical methods, immunoassay, etc. are used, which demand for expen- sive devices and organic solvents. Potentiometric sensors let one expressively detect cefalosporin antibiotics in small samples without previous sample preparation.

Effect of Surface Plasmon Resonance in the Fluorometric Properties of Molecules and Complexes

The optical properties of noble metal nanoparticles feature the pres- ence of a pronounced resonance band in the visible light spectrum, called the surface plasmon resonance band. The influence of local surface plasmons on the dynamics of singlet–triplet energy transfer in the donor–acceptor pair is the subject of recent active studies by analysts in connection with the prospective using of nanoparticles in optosensorics and the opportunity of significant improvements of the metrological characteristics of analytical techniques.

Preconcentration of Е110 and Е124 Food Azodyes on Magnetite Nanoparticles Modified by CTAB

Synthetic azodyes are widely used in paint, textile, plastic, and food, beverage, and leather, cosmetic, pharmaceutical and paper industries to make products more visually attractive to consumers. Therefore, they are also the components of waste waters and should be removed due to their potential risk to human health. Many techniques have been employed to eliminate dyes from waste water and do to preconcen- tration before analysis in food or beverage objects. One of the most popular and effective is magnetic solid-phase extraction (MSPE) with the use of magnetic nanoparticles (MNP).

Structure of Hydroperoxide Anion from the Viewpoint of Quantum Chemistry

In living nature, of significance is lipid peroxidation caused by highly- reactive oxygen-containing species. Hydroperoxide anion –OOH represents a protolytic kind of hydrogen peroxide H2O2 – one of active forms of oxygen, – and a precursor of hydroperoxyradical •OOH – another one. The work is aimed at the investigation of spa- tial and electronic structure of hydroperoxide anion.

Pages