Chemistry

Sensor System for Determining α-Amino Acids

The principles of creating ion-selective electrodes for a-amino acids in a historical retrospective are considered. It is shown that until recently, when the creation of potentiometric membrane sensors, the main emphasis was made on the formation of more selective sensors able to selectively determine the concentration of some analyte in multi-component systems. The material for such sensors were ionselective membranes, which were created specific to a particular analite, but were not specific to the entire class of such analyzers.

Spectrophotometric Study of the Stability the Quercetin and Rutin Solutions at Different Acidity of the Medium

Flavonoids are a group of polyphenolic compounds present in many plants, fruits, vegetables, nuts, flowers etc. They exhibit a wide range of bioactivity and have gained much attraction last two decades because of its potential applications in biology, medicine, and chemical analysis due to their antioxidant, medicinal (antiviral, antibacterial, antiallergic effects) and complexion properties. One of the main properties of flavonoids especially quercetin is their oxidation by oxygen dissolved in water or organic solvents mainly in basic media.

The Transformation of n-nonane in Conditions of Catalytic Cracking on ZSM-5 and V2O5/ZSM-5 Catalysts

The daily increasing demand for high-quality motor fuels requires constant improvement and modernization of existing technologies for oil refining. One of the main secondary processes of recycling hydrocarbon raw materials in industry, which allows to obtain high-octane components of automobile gasoline, valuable liquefied gases and raw materials for petrochemical industries is catalytic cracking of various types of distillate and residual raw materials. Nowadays, most catalysts of an industrial catalytic cracking contain expensive rare earth elements and platinum in its composition.

Some Transformation 2-Pentene-, Pentane-1,5-Diones and Their Halogen-Substituted Analogues with Thioacetamide

Given the ability of 1,5-dicarbonyl compounds to emerge in the presence of ammonia, urea and its derivatives of N-containing heterocyclic compounds, possibility of сyclization 2-pentene- and pentane-1,5-diones and their dihalogensubstituted analogues with thioacetamide.

Chromatographic Separation of Some Triazines by HPLC

Sorption properties of simazine, atrazine, propazine and prometrin on commercial chromatographic columns of LiChrospher 60 RP select B, Hypersil BDS-C18, and Zorbax SB-C18 were studied by reversed-phase high-performance liquid chromatography with photodiode matrix detection. The influence of the composition of the mobile phase on the chromatographic characteristics of the separation is considered. It was found that with the content of acetonitrile in a mixture of PF from 10 to 30 vol/vol. the chromatographic peak of atrazine is practically not manifested.

Physico-mechanical Properties of Silicon-chitosan-containing Glycerohydrogels Plates Based on Chitosan L- and D-ascorbates

Silicon-containing glycerohydrogel thin-film plates based on chitosan L- and D-ascorbates were obtained by means of biomimetic sol-gel synthesis using silicon tetraglycerolate as a biocompatible precursor. Their stress–strain characteristics were studied. For all the samples of our glycerohydrogel plates, stress–strain curves were recorded, characteristic of soft plastic polymeric materials not reaching their yield point under tensile conditions. At rupture, the material shows some characteristic signs of macroscopic plasticity.

Polymeric Sorbents for the Collection of Oil and Oil Products from the Surface of Reservoirs: a 2000–2017 Review of the English-language Literature (Part 2)

Oil spills after tanker and pipeline accidents pose a serious threat to the environment, lead to the loss of energy carriers and severely pollute seawater. Mechanical extraction by sorption mechanism is an effective means of oil spill liquidation from the surface of reservoirs. The English 2000–2017 scientific and technical literature devoted to the design of sorbents based on polymeric materials for the collection (absorption) of spilled oil and oil products from the surface of reservoirs with the possibility of subsequent recovery of the useful product was searched and analyzed.

Features of the Reactions of n-hexane on the Catalyst NH4(ZHM)

The process of catalytic reforming remains one of the main processes of the modern petrochemical industry, allowing for obtain commodity products – gasoline, with high detonation resistance and raw materials for the petrochemical industry – aromatic hydrocarbons. One of the most important tasks of improving the reforming process is the development of new efficient catalytic systems that don’t have noble metals in their composition.

Quantum-chemical Studies of Several Lanthanide Compounds with Products of Starch Thermal Decomposition

Lanthanide complexes with organic ligands (including hydrocarbons) find application in medicien as luminescent biomarkers for various pathogenic bacteria. At the same time, starch (as a polysaccharide) can serve as a source for carbon nanoparticles (via thermal decomposition) that have very intensive and longliving luminescence, thus such nanoparticles conjunctioned with lanthanides may be used to create more effective medical probes.

Synthesis and Functionalization of Magnetite Мagnetic Nanoparticles with Сhitosan

Superparamagnetic magnetite nanoparticles (MNP) have gained much attraction from the beginning of 21century because of its potential applications in biology, medicine, theranostics, physics, chemistry and chemical analysis due to unique multifunctional properties, including small size, superparamagnetic behavior, low toxicity, high adsorption properties used for magnetic solid-phase extraction (MSPE) in water purification and chemical analysis.

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