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Determination of Pesticide Residues in Grapes and Tomatoes by High Resolution Mass-spectrometry

Authors: Amelin V. G., Andoralov A. M.

A method for determining the 20 pesticides (azoxystrobin, boscalid, chlorpyrifos, cyprodinil, diazinon, dimethoate, fluazifop-P-butyl, malathion, metribuzin, penconazole, phosalone, pirimicarb, piri- miphos-methyl, prometryn, propargite, pyraclostrobin, pyrimethanil, triadimenol, triadimefon, trifloxystrobin) in grapes and tomatoes by high performance liquid chromatography with tandem quadrupole – time of flight mass spectrometry detector (HPLC-MS / TOF), using sample preparation QuEChERS.

Effect of Temperature, Isotopic Composition of Water and Ethanol on the Tautomeric Equilibrium of Sulphonated Phenylazonaphtholes

Authors: Al-Saidi M. Z., Shtykov S. N.

The effect of temperature, isotopic composition of water and ethanol on the tautomeric equilib- rium of two phenylazonaphtholes that differ by sulphonic group in benzene ring was investigated spectrophotometrically. It was established that enhancement of water structure under decrease of temperature or change of common water to heavy one shifts the azoquinonhydrazone tautomeric equilibrium to more polar hydrazone tautomer. The destruction of water structure and decrease of solvent polarity at ethanol addition, on the contrary, increases the concentration of azotautomer.

Modeling of Adiabatic Potential Parameters for Monosubstituted Benzenes, Pyridines, Pyrones and Thiopyrones

Authors: Pankratov A. N.

By means of the Density Functional Theory DFT (B3LYP) method, quantum chemical computations of fundamental vibrations spectra of monosubstituted benzenes, pyridines, pyrones and thiopyrones have been carried out. The possibility of the aforesaid method application for the studied series of compounds vibrational spectra prediction have been substantiated.

Fragmentation Canals of Molecular Ions of GC-MS-Registered Components of Media of Shiitake Basidiomycete Submerged Cultivation in the Presence of Diacetophenonylselenide. Isomerization of Dihydrofurans and Their Cation Radicals

Authors: Pankratov A. N., Tsivileva O. M., Tsymbal O. A., Yurasov N. A.

The molecular ions fragmentation canals of substances registered by means of the GC-MS method in the media of Lentinula edodes (shiitake) basidiomycete submerged cultivation in the presence of diacetophenonylselenide have been substantiated. At the B3LYP/6-311++G(3df,3pd) and UB3LYP/6-311++G(3df,3pd) level, involving the NBO analysis and the R. F. W. Bader’s «Atoms in Molecules» quantum theory (QTAIM), isomeric transformations of dihydrofurans have been considered.

The Peculiarities of Synthesis of Acid Esters of Methylphosphonic Acid

Authors: Denisov N. S., Tumskiy R. S.

The peculiarities of synthesis of acid esters of methylphosphonic acid for further use in the system of chemical and analytical control of the environment have been discovered.

Mass Fraction Evaluation of the Basic Substance in Dialkyl Methylphosphonate Samples by Potentiometric Titration

Authors: Uglanova V. Z., Denisov N. S.

A technique for the mass fraction evaluation of the basic substance in dialkyl methylphosphonate samples by automatic potentiometric titration is presented. A comparison was made with a certified technique of visual titration. Several advantages of our method are shown: the ability to automate analysis, a reduced sample weight, a constant and precise volume of a titrant drop, a reduced detection time, avoiding the use of chemical indicators, an improved precision of analysis.

Determination of the Contents of Arsenic, Mercury, Copper, Nickel and Zinc in the Soil and Ventilating Emissions by Method of Atomic Absorption Spectrometry (AAS)

Authors: Demakhin A. G., Akchurin S. V.

The method of atomic absorbing spectrometry (AAS) determined the content of mobile forms of copper, nickel and zinc, and total content of mercury and arsenic in the soil samples selected in a residential zone Samara, and copper in the ventilating emissions. For soils the sample preparation stage contribution to the general error of analytical definition is estimated. For ensuring correctness definition of the content of copper in the ventilating emissions the correction coefficient cons idering existence of a systematic mistake is calculated.

Determination of the Contents of Arsenic, Mercury, Copper, Nickel and Zinc in the Soil and Ventilating Emissions by Method of Atomic Absorption Spectrometry (AAS)

Authors: Lobachev А. L.

The method of atomic absorbing spectrometry (AAS) determined the content of mobile forms of copper, nickel and zinc, and total content of mercury and arsenic in the soil samples selected in a residential zone Samara, and copper in the ventilating emissions. For soils the sample preparation stage contribution to the general error of analytical definition is estimated. For ensuring correctness definition of the content of copper in the ventilating emissions the correction coefficient considering existence of a systematic mistake is calculated.

Synthesis and Luminescence Studies of Terbium Complex with 2,6-dibenzylidenecyclohexanone

Authors: Pozharov M. V., Zakharova T. V.

Novel complex of terbium (III) with aromatic monoketone – 2,6-dibenzylidenecyclohexanone – has been synthesized. Its uncharacteristic luminescent properties have been studied using quantum chemical calculations and lumiscent spectroscopy.

Synthesis of Monodisperse Magnetite: The Effect of Temperature, Sodium Hydroxide and Citric Acid Concentrations on the Size of Nanoparticles

Authors: Egunova O. R., German S. V., Shtykov S. N., Vrabie Y. A.

The effect of temperature, sodium hydroxide and citric acid concentrations on the size of magnetic magnetite nanoparticles was studied. Optimal conditions for synthesis of magnetite stabilized by citric acid with narrow size distribution were found. The average size of the nanoparticles determined by dynamic light scattering and transmission electron microscopy 12 ± 3 and 6 ± 2 nm, respectively was established. The chemical composition and structure of magnetite nanoparticles was confirmed by X-ray diffraction method.

Selective Determination of Histidine in Mixed Solutions of α-Amino Acids

Authors: Chernova R. K., Varygina O. V., Bereskina N. S.

Examined the condition of the main and neutral α-amino acids in aqueous media. Graphs of the distribution of ionized forms of histidine and alanine with varying pH. Pakistan the possibility of pH –metric selective determination of histidine in mixtures of neutral amino acid with a glass indicator electrode. The error does not exceed 7%

Viscous Degradation of Acidic Chitosan Solutions and its Ionic Probe Study

Authors: Boyko I. S., Podkolodnaya O. A., Lysachok S. G., Shmakov S. L.

A review of the literature on the phenomenon of aging (a significant drop in viscosity over time) of acidic chitosan solutions is given. A study was made on acetic acid (2%) solutions of chitosan of two viscosity-average molecular weights (200 and 46 kDa) by ion probing (addition of a KI solution). It has been indirectly confirmed that the motion of the probing ions in an electric field disturbs part (about a quarter) of the average macromolecule rather than the whole one.

Ethanol Conversion on Zeolites

Authors: Kuzmina R. I., Pilipenko A. Y., Khoroshilov I. I., Frolov M. P.

The possibility of converting the biomass to products of petrochemical synthesis is shown. The analysis of the development of the synthesis of catalysts for production of motor fuels from bioethanol is carried out. By varying the composition of the catalysts and the process conditions can be synthesized gasoline range hydrocarbons, ethylene, aromatic hydrocarbons. A scheme for the conversion of ethanol to hydrocarbons of various classes is discussed.

Reaggregation Positional Isomers Tetrazologeksahidroquinazoline

Authors: Vasilkova N. O., Borisova M. Y., Yurasov N. A., Krivenko A. P.

9-phenyl-4,5,6,7,8,9-geksagidrotetrazolo[5,1-b]quinazoline in solution undergoes reaggregation ent via an azide to form a positional isomer corner structure that is installed involving spectral methods (1H-NMR, IR -spectra), TLC, chromato-mass spectrometry.

Quantum Chemical and Infrared Spectrometric Studies Sulfoderivatives Di- and Triphenylamines

Authors: Burmistrova N. A., Mushtakova S. P.

The result of quantum-chemical studying of geometric characteristics for aromatic amine sulfoderivatives at MP2/6-31G(d,p) as well as experimental and theoretical investigation of IR spectra of these compounds are presented. It was shown for triphenylamine (TPhA) and triphenylamine-4-sulfonic acid (TPhASA) that theoretical vibrational spectrum was in good agreement with experimental data.

Multivariate Regression Methods for Simultaneous Сatalimetry Determination of Iridium (IV) and Rhodium (III)

Authors: Burmistrova N. A., Chernozubova E. V., Mushtakova S. P.

Application of multivariate regression methods for catalimetry simultaneous determination of iridium (IV) and rhodium (III) based on oxidation of N-methyldiphenylamine-4-sulphonic acid by periodations in weak acid medium was investigated. The data structure of the kinetic measurement was studied with Principal Component Analysis, it was found that the distribution of the samples corresponds to an increase in the total concentration of the catalysts of the PC1 and change the concentration ratio Ir: Rh on PC2.

Quantum-chemical Evaluation of Thermal Stability of Some Lanthanide Complexes with Methoxybenzoate

Authors: Pozharov M. V., Zakharova T. V., Makushova G. N., Kosolapova M. Y.

Structural and energetic parameters of neodymium, europium, terbium and erbium complexes with 2- and 3-methoxybenzoic and 3,4-dimethoxybenzoic acids were studied. Correlation between Ln-O bond energy and temperatures of decomposition of studied compounds was found.

Phase Equilibria and Critical Phenomena in the Water–i-Butyric Acid Binary System

Authors: Smotrov M. P.

Phase equilibria and critical phenomena in the water-i-butyric acid binary system were studied by the visual polythermal method over the temperature range –10–30°C. The system is characterized by delamination with an upper critical solution temperature (UCST) equal 25.8°C. In the system at –1.8°C, these occurs a nonvariant monotectic equilibrium whose solid phase are ice crystals. The phase diagram of the system is plotted.

Determination of the Main Substances in the Preparations of Cephalexin and Cefuroxime Axetil

Authors: Kulapina E. G., Karenko V. A., Kulapina O. I.

Techniques of determination of the main substances in capsules of cephalexin and tablets of cefuroxime axetil have been elaborated. For separation of ancillary compounds, the two modes have been approbated, i.e. filtration and centrifugation. The advantage of the second means has been shown.

Determination of Caffeine and Some Food Additives Wines, Energy and Soft Drinks

Authors: Selifonova E. I., Salkova D. V., Chernova R. K.

The method of capillary electrophoresis to determine the content of caffeine and food additives: ascorbic (E300), sorbic (E200), benzoic (E210) acids; sweeteners – saccharin sodium (E954), acesulfame potassium (E 950) in wines, energy drinks and tea. The comparative characteristic of the caffeine content, and the aforementioned food additives in beverages. A comparison with the corresponding regulations. It is shown that the concentration of benzoic acid in beverages above the maximum allowable concentration in beverages Flesh and MONETO.

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