Izvestiya of Saratov University.
ISSN 1816-9775 (Print)
ISSN 2541-8971 (Online)


Химия

Выявление фальсификации икры рыб методом масс-спектрометрии с индуктивно-связанной плазмой

Предложено использование метода масс-спектрометрии с индуктивно-связанной плазмой для дифференциации натуральной и имитированной икры по элементному составу различных видов рыб: лососевых, осетровых и частиковых пород. В качестве инструментов многомерного статистического анализа применяли метод главных компонент (PCA) и иерархический кластерный анализ (HCA). Использование PCA и HCA позволило эффективно визуализировать различия между пробами икры по признаку подлинности.

Выявление фальсификации икры рыб методом масс-спектрометрии с индуктивно-связанной плазмой

Предложено использование метода масс-спектрометрии с индуктивно-связанной плазмой для дифференциации натуральной и имитированной икры различных видов рыб: лососевых, осетровых и частиковых пород. В качестве инструментов многомерного статистического анализа применяли метод главных компонент (PCA) и иерархический кластерный анализ (HCA). Использование PCA и HCA позволило эффективно визуализировать различия между пробами икры по признаку подлинности.

Polythermal study of phase behavior and extractive crystallization of salt in the ternary system ammonium sulfate – water – polyethylene glycol-1500

Phase equilibria and solubility have been studied by the visual polythermal method in mixtures of components in nine sections of the composition triangle in the range of 10–70° C in the ternary system ammonium sulfate – water – polyethyleneglycol-1500 (PEG-1500). The dependence of the compositions of solutions corresponding to the critical solubility points of the stratifi cation region on temperature has been found using the liquid phase volume ratio method.

The influence of pressure on the composition of products from the catalytic conversion of n-hexane

At present, the most common industrial method for producing high-quality gasoline, characterized by high octane numbers and moderate aromatic hydrocarbon content, particularly benzene, is catalytic reforming. In the current trend of oil refi ning industry development, a promising method for improving straight-run motor fuels is co-processing, where the combination of the most optimal parameters allows for the production of high-octane gasolines with the best performance and environmental characteristics.

Influence of electrospinning conditions on the characteristics of a nonwoven material based on fl uoroplast P(VDF-TFE)

Nonwovens produced through electrospinning technique have been successfully used in various fi elds due to their unique properties. It is essential to investigate the impact of the parameters in the manufacturing process on the resulting properties of these materials. This research focuses on nonwovens made from fl uoroplast P(VDF-TFE) using a horizontal spraying system with a vertically positioned collector. The parameters studied include the interelectrode distance, the electric fi eld strength, and the viscosity of the molding solution.

Express determination of ceftriaxone using immobilized copper sulfate (II)

Indicator papers based on immobilized copper (II) sulfate have been obtained for the determination of the β-lactam antibiotic ceftriaxone. The interaction of immobilized copper (II) sulfate with ceftriaxone has been assessed using diff use refl ectance spectroscopy. Methods have been developed for visual colorimetric and colorimetric determination of the antibiotic using a smartphone camera, Adobe Photoshop CS5® software, and a regression model built using the Python programming language. Color test scales for rapid assessment of ceftriaxone content have been obtained.

A new variant of the Friedlander reaction in the synthesis of 7,8-dihydro-6H-furo[2,3-b] quinolin-5-ones

Hydrogenated derivatives of acridine exhibit various types of biological activity – their antibacterial, antitumor, antiviral, psychoactive properties are known. Using the example of heteroanalogs of tacrine, a known cholinesterase inhibitor, it is shown that the replacement of the benzene ring in polycyclic systems with a fi ve-membered heterocycle leads to a decrease in the toxicity of the drug, but does not change the basic physiological activity. Thus, the synthesis of heteroanalogs of known benzannelated systems is an urgent task.

Carbonyl olefi nation of N-substituted tetrahydroquinoline-6-carbaldehydes

Tetrahydroquinolines are important structural fragments of many biologically active compounds exhibiting antifungal, antitumor, antiviral and neurotropic properties. This paper presents methods for the synthesis of N-substituted tetrahydroquinoline-6-carbaldehydes and a study of the possibility of their olefi nation using the Wittig and Horner – Wadsworth – Emmons methods. As a result of the interaction of N-alkyl- and N-acylhydroquinolines with the Vilsmeier – Haack complex, N-substituted tetrahydroquinoline-6-carbaldehydes have been obtained in yields of 77–85%.

A Comparative Study of Benzene and Toluene Adsorption on KOH-Modified AR-A Activated Carbon: Effect of Concentration and Impregnation Ratio

This study compares the adsorption of benzene and toluene vapors on potassium hydroxide (KOH)-modified AR-A activated carbon (AC), considering their toxicological impact. The primary objective was to evaluate how different KOH concentrations and impregnation ratios influence the adsorption capacity and kinetics for these volatile organic compounds (VOCs). The AC samples were chemically modified using KOH at concentrations of 0.5 M and 1.0 M, using mass-to-volume impregnation ratios of 1:5 and 1:10.

Исследование влияния параметров процесса соосаждения на физико-химические характеристики прекурсора катодного материала NCM811

Подбор параметров синтеза прекурсоров катодных материалов состава NCM является одним из превалирующих факторов, оказывающих существенное влияние на химический состав, насыпную плотность, микроструктуру поверхности, электрохимические характеристики и ресурс получаемых впоследствии катодных материалов. В данной работе исследуется варьирование скорости перемешивания, pH, концентрации комплексообразующего агента, мольное соотношение концентраций NH3/р-р сульфатов.

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