bluuebunny/crossref_metadata_2025 huggingface dataset:
Regular Density Inhomogeneities in the Boundary Layer of the Plasmasphere
Authors: Kotova G. A. , Bezrukikh V. V. , Chugunin D. V. , Mogilevsky M. M. , Chernyshov A. A.
Published: April 2024

Based on thermal plasma measurements on the MAGION-5 and INTERBALL-1 satellites in the plasmasphere boundary layer, similar recurring changes in the proton density were identified depending on the L-shell. Such density variations have the following characteristic features: (a) density variations occur sharply, on the density profile—the dependence of density on L or on geomagnetic latitude λ—they have a sawtooth nature, and the density of protons at the peaks (maxima) of variations exceeds that at the minima of variations by two to eight times; (b) the characteristic size of variations in the radial direction in the plane of the geomagnetic equator is ~0.15 RE or ~1000 km; (c) sawtooth changes in proton density in the plasmasphere boundary layer can span at least 90° in longitude; (d) regular variations in plasma density were observed at geomagnetic latitudes up to 30°, and this latitude is limited to the orbits of satellites whose data were used for the analysis. Sawtooth variations in thermal plasma density are apparently related to spatial structures that evolve but persist in the plasmasphere boundary layer, at least over the course of a day. Plasma inhomogeneities were observed in fairly quiet or slightly disturbed geomagnetic conditions. The considered inhomogeneities are probably a consequence of the interchange or quasi-interchange instability developing in the plasmasphere boundary layer.
A Potentiometric Sensor for Cesium Ions with a Film Membrane Based on Dibenzo-21-Crown-7
Authors: Brechalov A. A. , Babitova E. S. , Timoshenko V. V. , Eremin V. V. , Kalinin E. O. , Kalyagin D. S. , Smirnov I. V. , Ermolenko Yu. E.
Published: April 2024

A new type of potentiometric sensor for cesium ions based on a crown ether (dibenzo-21-crown-7) is proposed; its analytical characteristics are presented: limit of detection, slope of electrode function, selectivity to a number of interfering ions, and the working pH range of solutions.
Determination of Glyphosate, Its Metabolite, and Glufosinate in Products of Plant Origin by Chromatography–Mass-Spectrometry
Authors: Sorokin A. V.
Published: April 2024

A selective procedure is developed for the determination of glyphosate, aminomethylphosphonic acid, and glufosinate in raw materials of plant origin by chromatography–mass spectrometry. The limit of quantification for glyphosate is 0.1 mg/kg and for glufosinate and aminomethylphosphonic acid, 0.4 mg/kg. The procedure is based on the extraction of analytes from a sample with deionized water acidified with hydrochloric acid, solid-phase purification followed by derivatization with 9-fluorenylmethoxycarbonyl chloride, and the additional purification of the derivatives on a sorbent with weak cation-exchange properties. The extraction and purification procedures for the extracts are optimized. The effect of matrix components on the chromatographic separation and detection of glyphosate on chromatographs–mass spectrometers of various types is studied. Validation of the developed procedure showed that the relative expanded uncertainty lies in the range from 15 to 25%.
Passive Adsorption of Aromatic Substances on Silicon Carbide and Nitrile Rubber Composites and a Comparison of the Chromatographic Profiles of Banana Candy, Fresh Banana, and “Banana” Flavor
Authors: Popik M. V. , Shpigun O. A. , Stepashkin A. A. , Markova E. S. , Furman A. N. , Shekhtman S. P. , Pirogov A. V.
Published: April 2024

A domestic composite material based on silicon carbide and nitrile butadiene rubber was used to identify volatile substances of banana, banana flavor, and creamy chewing candies by passive adsorption in combination with thermal desorption GC–MS. This method can be used to determine a wide range of compounds, for example, esters of carboxylic acids, terpenoids, aldehydes, aromatic hydrocarbons, alkanes, heterocyclic compounds, phenols, glycerides, and fatty acids. The obtained chromatographic profiles of the samples were compared. In the chromatogram of “Banana” flavor, five peaks (out of eight) corresponded to the compounds that form the aroma of a banana, and in the chromatogram of “Love is” candies with banana flavor, three corresponding peaks (out of 21) were found.
Methods for the Determination of Arsenic in Metallurgical Materials
Authors: Belozerova A. A. , Pechishcheva N. V. , Shunyaev K. Yu.
Published: April 2024

The review summarizes the results of publications on methods for determining arsenic in metallurgical materials from 2000 to 2022
Multilayer Coatings Based On Citrate-Stabilized Gold Nanoparticles and Polydiallyldimethylammonium Chloride for the Electrophoretic Separation of Carboxylic Acids
Authors: Makeeva D. V. , Antipova K. S. , Solovyeva E. V. , Morgacheva V. P. , Kolobova E. A. , Kartsova L. A.
Published: April 2024

The conditions for the formation of physically adsorbed three-layer coatings of quartz capillary walls in capillary electrophoresis (CE) with successively deposited oppositely charged layers of polydiallyldimethylammonium chloride (PDADMAC) modifiers and citrate-stabilized gold nanoparticles (GNPs) are proposed. It was shown that three-layer PDADMAC–GNP–PDADMAC coatings favorably differ from monolayer coatings with PDADMAC by greater stability in a wide range of pH (2–10). The formed coatings were characterized by scanning electron microscopy, and the presence of a uniform dense layer of nanoparticles on the capillary surface was confirmed. The applicability of the modified capillaries under CE conditions was demonstrated by the separation of a mixture of 16 carboxylic acids. An increase in the separation selectivity achieved with the use of three-layer coatings based on GNPs was explained by the reversible exchange of citrate anions on the GNP surface with negatively charged analytes in the course of electrophoretic analysis.
Determination of Viscosity Improvers and Detergent Additives in Synthetic Motor Oils by Gel Permeation Chromatography
Authors: Temerdashev Z. A. , Ivanova Yu. A. , Litvinenko D. A. , Makhotkina D. A.
Published: April 2024

We proposed a procedure for the simultaneous determination of viscosity improvers and detergent additives in synthetic oils by gel permeation chromatography, including the preliminary liquid extraction of polar additives, solid-phase extraction of polymer additives on silica modified with magnesium oxide from oil raffinate, and the subsequent determination of analytes. The procedure was used to determine viscosity improvers and detergent additives in fresh and used synthetic motor oils, to control the quality of oils at different stages of operation, and to monitor the degree of purification of oils during their regeneration. In-process monitoring of additive concentrations during the operation of automotive equipment enables the timely control of the dynamics of engine oil degradation throughout its use and proper recommendations for its replacement in the system. The procedure was tested in the analysis of fresh and used multigrade synthetic motor oils Shell Helix Ultra 5W-30 and TP MAX Total 10W-40 and fresh multigrade synthetic motor oil Shell Rimula R5M 10W-40.
Determination of the Matrix Composition of Glasses of the Ga–Ge–Te–I System by Inductively Coupled Plasma Atomic Emission Spectrometry
Authors: Evdokimov I. I. , Kurganova A. E. , Velmuzhov A. P.
Published: April 2024

A procedure is developed for the high-precision determination of matrix elements of high-purity glasses of the Ga–Ge–Te–I system, containing from 5 to 15 at % Ga, from 10 to 20 at % Ge, from 69 to 75 at % Te, and from 1 to 6 at % I, using inductively coupled plasma atomic emission spectrometry. The procedure includes two stages independent of each other: determination of the ratio of the mass fractions of Ga and Te to the mass fraction of Ge (stage 1) and determination of the mass fraction of I (stage 2) in the glass sample. Based on these values, the mass and mole fractions of each matrix element of the analyzed sample were calculated. Sample preparation includes the acid dissolution (provides quantitative transfer of Ga, Ge, and Te into the solution) and alkaline opening (provides quantitative transfer of I into the solution) of samples. The accuracy of the results of analysis was confirmed by comparing the results of an analysis of model solutions and model glass samples with the calculated composition. The estimated uncertainty of the results of analysis is 0.05–0.1 at % at P = 0.95.
Using a Magnetic Sorbent Based on Hypercrosslinked Polystyrene in Combination with Gas Chromatography–Mass Spectrometry for the Determination of Chlorophenols in Freshwater Fish
Authors: Gubin A. S. , Sukhanov P. T. , Kushnir A. A.
Published: April 2024

A combination of solid-phase extraction on a magnetic sorbent based on hypercrosslinked polystyrene and gas chromatography–mass spectrometry is proposed for the determination of chlorophenols in freshwater fish. I2-Chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol were identified in samples of roach (Rutilus rutilus) and silver carp (Hypophthalmichthys molitrix). The accumulation of chlorophenols in various organs and tissues of fish (muscles, liver, milk, caviar, body fat) living in the Voronezh reservoir was studied. Methods for sample preparation were developed and the interfering influences of various factors on the determination results were found. Oil products and fatty acids make the greatest contribution to matrix effects. The limits of the determination of chlorophenols by the developed method are 7–18 ng/kg in muscle tissue and liver and 30–60 ng/kg in fat-containing tissues. The maximum amounts of chlorophenols were found in the fat deposits of silver carp and amounted to 100, 82, 434, 1529, 383 and 411 ng/kg for 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol, respectively.
A Comparison of the Peak-to-Background Method and an Empirical Correction of the Results in the Energy-Dispersive Electron Probe Quantitative Analysis of Powder Materials
Authors: Pukhov D. E.
Published: April 2024

Several algorithms for correcting the results of the quantitative electron probe elemental analysis of samples with rough surfaces and powder materials are compared. The effectiveness of the methods was estimated by the deviations of corrected weight fractions of elements from the results obtained for reference samples, i.e., polished plates of test materials. Using the most commonly used peak-to-background method, the intensity of continuous X-ray radiation was calculated by several methods. One method involved the analytical calculation of the bremsstrahlung generation function and the correction of the width and shape of the bremsstrahlung spectrum under the diagnostic lines of the elements based on the experimental spectra. The second, more rapid method was based on the direct simulation of the continuous radiation background by Monte Carlo methods in the NIST DTSA-II software environment. The last method of calculating the background of continuous radiation yielded smaller deviations of the results of quantitative analysis from the results obtained for reference samples. An empirical adjustment method was also tested. It was based on experimentally revealed patterns in the energy-dispersive spectra of powder samples. An analysis of the experimental data revealed an empirical dependence relating the parameters of characteristic photons to the value of accelerating voltage required to obtain the proper ratio of the weight concentrations of elements in the analysis of powdered materials. The proposed empirical method for correcting the results of analyses of powder samples based on the totality of the measurements performed is more effective.
A Comparative Study of the Dynamic Fractionation of Rare-Earth Elements in Soils Using a Rotating Coiled Column and a Microcolumn
Authors: Shatrova Yu. N. , Dzhenloda R. Kh. , Fedyunina N. N. , Karandashev V. K. , Fedotov P. S.
Published: April 2024

Rare earth elements (REEs) are currently used in fertilizers, but their behavior in the soil–plant system remains poorly studied. The assessment of the binding of REEs to various organomineral phases of soils remains an important task. Using soddy-podzolic soil and typical chernozem as examples, we performed a comparative study of the dynamic fractionation of REEs in a rotating coiled column (RCC) and a microcolumn (MC). We isolated the exchangeable fraction, specifically adsorbed fraction, and fractions bound to manganese oxides, bound to organic matter, and bound to amorphous and weakly crystallized iron and aluminum oxides using, 0.05 M Ca(NO3)2, 0.43 M CH3COOH, and a 0.1 M NH2OH·HCl solution (pH 3.6), a 0.1 M K4P2O7 solution (pH 11.0), and a 0.1 M (NH4)2C2O4 solution (pH 3.2), respectively. Concentrations of elements in the initial samples and eluate fractions were determined by atomic emission spectrometry and inductively coupled plasma mass spectrometry. The results suggest that the main extractable REE form (up to 40% of the total content) is provided by organometallic complexes extracted with a 0.1 M K4P2O7 solution. For chernozem (soils with a high content of organic matter), fractionation in the RCC and MC yielded comparable results. For soddy-podzolic soil, some differences were observed in the isolation of the first three fractions: exchangeable, specifically adsorbed, and bound to manganese oxides. Both RCC and MC can be successfully used for the dynamic fractionation of REE in soils; however, it is preferable to use an MC in analyzing many samples as a simpler and more affordable device.
Dispersive Liquid–Liquid Microextraction of Preservatives for Their Chromatographic Determination in Beverages
Authors: Kochetkova M. A. , Timofeeva I. I. , Bulatov A. V.
Published: April 2024

A method of dispersive liquid–liquid microextraction, based on the dispersion of an extractant by the gas phase formed as a result of a phase transition, i.e., the evaporation of a highly volatile nonpolar organic solvent (dispersant) upon heating the extraction,—is developed. The analytical capabilities of the method are shown in the determination of preservatives (sorbic and benzoic acids) in soft drinks for baby food by high-performance liquid chromatography with photometric detection. The extractant and the dispersant for the microextraction of preservatives are chosen a terpenoid and a highly volatile organochlorine solvent, respectively, which excluded the use of polar organic solvents for dispersing phases, with which the distribution coefficients are reduced. The limits of detection (3σ) for sorbic and benzoic acids are 0.3 mg/L. The developed method does not require centrifugation for phase separation
Using Highly Sensitive Piezo Sensors in an Open System for the Diagnostic Analysis of Skin Volatile Substances
Authors: Kuchmenko T. A. , Menzhulina D. A. , Murakhovskii I. A.
Published: April 2024

A single sensor with a piezoelectric quartz transducer is considered a platform for simulating an “electronic nose” that performs the function of a sensor array. The analytical task was to detect volatile organic compounds, component-by-component, in biosamples at diagnostically relevant concentrations without selecting mixtures or any sample preparation. We confirmed the fundamental possibility of utilizing a single sensor for the separate detection (recognition) of vapors of organic compounds and various functional states of a body during a short contact (60–80 s) with skin, the most representative and constantly performing bioassay. Modifying the electrodes of bulk acoustic wave piezoelectric quartz resonators with 2–4 μg of the nanohydroxyapatite phase is an essential step in solving the problem. The newly calculated adsorption kinetic parameters can be used to detect biomarkers of many diseases with high reliability, including С3–С5 alcohols, ketones, linear and cyclic amines, acids, aldehydes, etc. The hydroxyapatite sensor can detect molecules pointing to problems with many organs, and any abnormalities in the functioning of the nervous and cardiovascular systems. It can also measure the body’s responses and compensatory mechanisms in relation to stress, hunger, and fatigue. The sensor has a potential as a simple diagnostic and monitoring tool for point-of-care diagnostics of both adults and children.
Isolation of Nanoparticles from Soil and Dust and Their Study by Single Particle Inductively Coupled Plasma Mass Spectrometry
Authors: Ermolin M. S. , Fedotov P. S.
Published: April 2024

The study of natural and anthropogenic dust and soil nanoparticles is an urgent task of analytical chemistry and biogeochemistry, the solution of which requires the use of complementary separation and analysis methods. In this work, the existing approaches to the isolation of nanoparticles from natural polydisperse samples are summarized. Methods of extracting nanoparticles with aqueous solutions, a possibility of intensifying the process of extracting nanoparticles by an ultrasonic field, methods of cloud-point extraction, and also methods for purifying the separated fractions of nanoparticles from impurities of microparticles are considered. The advantages and disadvantages of these methods are evaluated. It is noted that the success of a study of soil and dust nanoparticles depends on the competent choice of a set of methods for isolating nanoparticles from polydisperse samples and their purification from microparticle impurities, as well as methods for the characterization and elemental analysis of nanoparticles. Particular attention is paid to single particle inductively coupled plasma mass spectrometry as a promising method for determining the concentration, size distribution, and elemental composition of nanoparticles.
Singly Charged Argide ArM+ Ions in Inductively Coupled Plasma–Mass Spectrometry
Authors: Pupyshev A. A.
Published: April 2024

Singly charged argide ArM+ ions in inductively coupled plasma–mass spectrometry (ICP–MS) can cause significant spectral interferences in the determination of all elements of the Periodic Table of the Elements with atomic numbers above 36 and measurements of their isotopic composition. This review presents examples of the such characteristic interferences and respective recommended and used interference tables for different elements. Published data on the determination of the dissociation energies of ArM+ ions by experimental and theoretical methods are summarized. The relationship between the dissociation energies of argide ions and their intensities in the mass spectrum is discussed. The experimental determination of the numerical values of the interference level ArM+/M+ in ICP–MS and the influence of various instrumental and operation parameters on this ratio are considered. The main options for the account and reduction of the effect of ArM+ in the mass spectra or elimination of the interference of argide ions are presented. A conclusion and recommendations on the considered publications are made.
QuEChERS Extraction of PAHs from Various Soils and Sediments Followed by Chromatographic Determination
Authors: Temerdashev Z. A. , Ovsepyan S. K. , Musorina T. N. , Vasileva L. V. , Vasilev A. M. , Korpakova I. G.
Published: April 2024

We studied the features of PAHs extraction by QuEChERS in the sample preparation of soils and bottom sediments of various compositions followed their determination by gas chromatography–mass-spectrometry. The test samples were soils of sandy, loamy sand, loamy, and clayey types and bottom sediments of loamy sand type. The mineralogical composition and organic matter content of the samples were used to predict how PAHs were retained by the soils and sediments. The impact of ultrasonic treatment on analyte extraction with subsequent identification by chromatography was assessed. No ultrasonic treatment was required to extract and determine all PAHs (up to 100%) in sandy and loamy sand soils and low-molecular-weight PAHs in all test samples. The QuEChERS extraction and determination of high-molecular-weight PAHs in clay type soil samples and loamy sand bottom sediments required a 10-min ultrasonic treatment, while the recoveries of analytes were higher than 87 and 90%, respectively. The analysis of a loamy soil sample with a high organic matter content was the most challenging. To extract over 70% of high-molecular-weight PAHs from a sample of this type using the QuEChERS technique, the binary acetonitrile–acetone (1 : 1) extractant rather than conventional acetonitrile was used with the simultaneous 15-min ultrasonic treatment.
Modern Approaches to the Extraction and Preconcentration of Biologically Active Compounds from Plant Samples by Microextraction Methods for Their Determination by Chromatography–Mass Spectrometry
Authors: Bessonova E. A , Karpitskii D. A. , Kartsova L. A.
Published: April 2024

The review considers the main trends in actively developing methods of solid-phase and liquid–liquid microextraction for the extraction, purification, and preconcentration of analytes from medicinal plants and plant materials, the use of new extractants and approaches to the preparation of samples of plant origin, and their compatibility with mass-spectrometric detection. Particular attention is paid to the analytical capabilities, advantages, and limitations of each of the approaches to extracting analytes from plant materials for the subsequent analysis of the obtained extracts by chromatography–mass spectrometry.
Specificities of the Fourier Transform Infrared Spectroscopic Methodology and Interpretation of Spectroscopic Data in Microbiological Analyses
Authors: Kamnev A. A. , Tugarova A. V.
Published: April 2024

In this mini-review, some of the most significant, from the authors’ point of view, features of the methodology of Fourier transform infrared (FTIR) spectroscopy and interpretation of experimentally obtained spectroscopic data are considered, as applied to the molecular spectrochemical analysis of microbiological objects using examples published in the specialised scientific literature mainly in recent years. Examples of typical inaccuracies and errors both of a methodological nature and arising in the interpretation of spectroscopic data are also presented and briefly discussed.
Planar Chromatography as a Method for the Analytical Control of Composite Pharmaceutical Preparations Based on N-Vinylamides
Authors: Krasikov V. D. , Malakhova I. I. , Santuryan Yu. G. , Panarin E. F.
Published: April 2024

Planar chromatography is used to develop methods for the analytical control of processes of the synthesis of biomedical polymers and their complexes with biologically active substances, which made it possible to create a number of long-acting antiviral, antitumor, antimicrobial, and antiseptic preparations.
A Voltammetric Sensor Based on Carbon Veil Modified with Graphene and Phytosynthesized Cobalt Oxide Nanoparticles for the Determination of Food Dyes Tartrazine (E102) and Allura Red (E129)
Authors: Buharinova M. A. , Khamzina E. I. , Kolotygina V. Yu. , Stozhko N. Yu.
Published: April 2024

A voltammetric sensor based on carbon veil modified with graphene nanoplates and phytosynthesized cobalt oxide Co3O4 nanoparticles is proposed for the determination of tartrazine (E102) and allura red AC (E129). The use of a composite nanomodifier contributes to an increase and better separation of the oxidation currents of azo dyes on their simultaneous presence. The process of the oxidation of azo dyes is irreversible, involves two electrons, and has a mixed nature. The sensor is characterized by a low limit of detection: 30 nM for E102 and 27 nM for E129, and in the inversion mode 16 and 3 nM, respectively. The analytical range the dyes is 0.1–15 µM. The sensor has been successfully used in the analysis of fruit jellies and beverage. The advantages of the developed sensor are high performance and operational characteristics, ease of manufacture, and low cost.
High-Temperature Thermodynamic Properties of Hafnium and Rare Earth Oxide Ceramics
Authors: Vorozhtcov V. A. , Stolyarova V. L. , Kirillova S. A. , Lopatin S. I.
Published: April 2024

Previous experimental data on the vaporization and high-temperature thermodynamic properties of hafnium and rare earth oxide ceramics are considered here. The La2O3–Sm2O3 system is for the first time studied at 2323 K using Knudsen effusion mass spectrometry. As a result of this study, the vapor composition over ceramic samples under investigation is identified, and concentration dependences of the partial pressures of vapor species over the system under study and condensed-phase thermodynamic properties are determined, namely, the component activities and the excess Gibbs energy. The enthalpy of formation from oxides and excess entropy of the La2O3–Sm2O3 system at 2323 K are determined using the Wilson polynomial. The Kohler, Redlich–Kister, and Wilson semiempirical methods were used to calculate the thermodynamic properties in the La2O3–Sm2O3–Y2O3–HfO2 and La2O3–Sm2O3–ZrO2–HfO2 quaternary systems at 2330 K using the equilibrium data gained in the relevant binary systems. The results of the calculations were compared to previous semiempirical estimates of the respective quantities for the La2O3–Y2O3–ZrO2–HfO2 and Sm2O3–Y2O3–ZrO2–HfO2 systems taken as examples. Calculations by the Wilson method are shown to provide the best match with the experimentally obtained lanthanoid oxide activities in the La2O3–Sm2O3–Y2O3–HfO2 and La2O3–Sm2O3–ZrO2–HfO2 systems.
The Effect of Silver Content in ZnO–Ag Nanoparticles on Their Photochemical and Antibacterial Activity
Authors: Bakina O. V. , Chzhou V. R. , Ivanova L. Yu. , Kazantsev S. O.
Published: April 2024

The development of new materials with antibacterial properties is a promising direction in the field of nanotechnology. In this work, ZnO–Ag nanoparticles with a silver content of 0.1–50 at % have been fabricated by the exploding wire method. ZnO–Ag nanoparticles absorb visible light and destroy the model dye Rhodamine B. The introduction of silver into nanoparticles has made it possible to shift the main absorption edge to 1.59–2.74 eV. The determined optimal content of silver in nanoparticles of 12 at % has ensured the degree of Rhodamine B decoloration by 85% within 60 min of exposure to visible light and has completely stopped the growth of E. coli bacteria at a concentration of 15.6 µg/mL. In addition, nanoparticles containing 12 at % silver have sterilized a sample of natural water contaminated with microorganisms. The results obtained offer an efficient method for the synthesis of antibacterial nanocomposites with heterojunctions employing a high-performance technique for producing nanoparticles, namely, the exploding wire method.
Thermodynamic Study of Sorption Processes of Gaseous Ferrocene on Organometallic Framework [Zn4(ndc)4(ur)2(dmf)]
Authors: Zelenina L. N. , Chusova T. P. , Sapchenko S. A. , Gelfond N. V.
Published: April 2024

The pressure of ferrocene in the system host (organometallic framework [Zn4(dmf)(ur)2(ndc)4])–guest (ferrocene) has been measured by static method with membrane zero-manometers in the temperature range from 324 to 462 K. As a result of the study, temperature dependences of pressure have been obtained for the transition of the guest from the host framework to the gas phase, the enthalpy and entropy of this process have been determined, and the change in the Gibbs energy during ferrocene binding by the framework has been calculated. Based on this information, conclusions have been made about the nature of interactions between host and guest molecules, and the obtained results have been compared with the previously studied benzene sorption on [Zn4(dmf)(ur)2(ndc)4].
Interaction of Copper(II) with Succinic Acid and Selected Amino Acids
Authors: Skorik N. A. , Vasil’eva O. A.
Published: April 2024

Spectrometry, spectrophotometry, pH-potentiometry, and solubility method have been used to study the reactions proceeding in aqueous solutions containing the “metal of life” ion Cu2+ and biologically active substances, succinic acid and (or) one of the amino acids (aminoacetic, glutamic, and aspartic). The general acid protonation constants, composition, and stability constants of homoligand and mixed ligand copper(II) complexes have been determined at ionic strength I = 0.3; for copper(II) succinate of the composition CuC4H4O4⋅2H2O, the solubility constant has been found (logKS = –7.59 ± 0.06).
Ba2Gd2 – xSmxGe4O13: Luminescence Properties, Prospects for Non-Contact Temperature Sensing Applications and Light-Emitting Diodes
Authors: Chvanova A. V. , Lipina O. A. , Chufarov A. Yu. , Tyutyunnik A. P. , Baklanova Ya. V. , Surat L. L. , Zubkov V. G.
Published: April 2024

Tetragermanates Ba2Gd2 – xSmxGe4O13 (x = 0.025–0.8) have been synthesized by the solid-phase method. Solid solutions crystallize in the monoclinic crystal system (space group С2/с, Z = 4) and are members of a small family of inorganic compounds containing [Ge4O13]10– anions. The photoluminescence properties of germanates upon excitation by radiation with λex = 275 nm have been studied. The spectra of the compounds show a broad band with a maximum at 313 nm and a set of lines in the range of 525–730 nm, corresponding to intraconfigurational 4f–4f transitions in Gd3+ and Sm3+ ions. It has been found that germanate Ba2Gd1.95Sm0.05Ge4O13 has the maximum luminescence intensity. For this sample, the color characteristics and the temperature dependences of the intensity ratios of the main luminescence bands upon heating to 498 K have been studied. It has been concluded that Ba2Gd1.95Sm0.05Ge4O13 can be used as a material for non-contact temperature sensing and light emitting diodes.
Spectrophotometric Study of Palladium(II) Complexation with Elementary Amino Acids in Aqueous Solution
Authors: Zharkov G. P. , Yastremskaya M. A. , Pavlushin A. V. , Petrova Yu. S. , Neudachina L. K.
Published: April 2024

Complex formation of aqua palladium(II) ions with glycine (Gly), β‑alanine (β-Ala), and taurine (Tau) in aqueous solution was studied by spectrophotometric titration at I = 1.0 mol/L (HClO4 + NaClO4) and T = 25 ± 1°C. A monoligand complex appeared at pH 0 in the H‒Pd–Gly system under the conditions of our experiment; mono- and biscomplexes were formed at pH 1. In the H‒Pd‒β-Ala system, a monoligand complex was formed at pH 1 and mono- and biscomplexes were formed at pH 2. In the H‒Pd‒Tau system, a monoligand complex was formed at pH 1 and 2. Molar absorption coefficients were calculated: the peak absorption occurs at λ = 370 nm and ε = 203 L/(mol cm) for the monoligand glycinate complex [PdGly(H2O)2]+; at λ = 325 nm and ε = 274 L/(mol cm) for the biscomplex [PdGly2]0; at λ = 365 nm and ε = 342 and 297 L/(mol cm) for the β‑alaninate [Pdβ‑Ala(H2O)2]+ and taurinate [PdTau(H2O)2]+ monoligand complexes, respectively; and at λ = 330 nm and ε = 549 L/(mol cm) for the β‑alaninate biscomplex [Pdβ‑Ala2]0. Logarithmic concentration formation constants were calculated for glycinate (log β1 = 15.03 ± 0.07, and log β2 = 28.97 ± 0.28), β-alaninate (log β1 = 13.94 ± 0.05, and log β2 = 25.24 ± 0.06), and taurinate (log β1 = 9.74 ± 0.08) palladium(II) complexes.
Thermochemical Investigations of Bismuth, Dysprosium, Samarium, and Niobium Oxide Compounds
Authors: Matskevich N. I. , Semerikova A. N. , Gelfond N. V. , Tkachev E. N. , Matskevich M. Yu. , Anufrieva O. I. , Bezverkhii P. P.
Published: April 2024

Ceramic Bi1.4Dy0.6O3 and Bi3Nb0.2Sm0.8O6.2 samples were prepared by solid-phase synthesis. The compounds have cubic structures (space group Fm3m). Their standard enthalpies of formation were determined by solution calorimetry, and their lattice enthalpies were calculated. The lattice enthalpies of Bi3Nb0.2R0.8O6.2 compounds decrease in magnitude when erbium is replaced by samarium, due to the lanthanide radius increasing from erbium to samarium. The lattice enthalpy of Bi1.4Dy0.6O3 has a greater magnitude than the lattice enthalpy of Bi1.2Gd0.8O3.
A New Method for the Synthesis of Layered Europium Hydroxide Using Propylene Oxide as the Precipitating Agent
Authors: Sheichenko E. D. , Yapryntsev A. D. , Rodina A. A. , Baranchikov A. E. , Ivanov V. K.
Published: April 2024

A new method for the synthesis of layered europium basic chloride in up to 90% yield was developed. The method is based on hydrolysis of europium chloride in the presence of propylene oxide. The effect of reaction temperature on the yield and composition of the products of europium chloride hydrolysis in the presence of propylene oxide was analyzed. The obtained layered europium basic chloride had pronounced anion exchange properties. The possibility of intercalation of the isonicotinate anion into a layered rare earth hydroxide was demonstrated for the first time. The intercalation of the benzoate or isonicotinate anions into layered europium hydroxide led to luminescence sensitization and decrease in the Eu3+ local symmetry.
Synthesis and Electrical Properties of Nd2(WO4)3–SiO2 Composites
Authors: Guseva A. F. , Pestereva N. N.
Published: April 2024

t—The (1 – x)Nd2(WO4)3–xSiO2 composites where the silicon oxide mole fraction is x ≤ 0.5 were manufactured by the solid-phase method. The phase compositions of the composites and their thermodynamic stability were verified by X-ray powder diffraction and thermogravimetry, respectively, in combination with differential scanning calorimetry (DSC). The morphology of the composites was studied by scanning electron microscopy (SEM) combined with energy-dispersive X-ray analysis. The electrical conductivity of the composites measured by electrochemical impedance was studied as functions of temperature, oxygen vapor pressure, and the amount of silicon oxide (the dispersed additive). The sums of ion transference numbers were studied as a function of temperature by the EMF method; the ionic character of conduction in the composites was found. The composite-conductivity effect was found to occur in the studied system: additions of 30 mol % nanosized silica to neodymium tungstate increased the ionic conductivity by more than two orders of magnitude.
Synthesis and Stabilization of Crystal Hydrate Modification SrSO4⋅0.5H2O
Authors: Bushuev N. N. , Sysoev A. A. , Velikodny Yu. A.
Published: April 2024

A method has been developed for the synthesis of the metastable trigonal modification SrSO4⋅0.5H2O, isostructural to the well-known CaSO4⋅0.5H2O modification (space group P3121). Frozen solutions of NaCl in water have been proposed as a precursor in the crystallization of SrSO4⋅0.5H2O. The SrSO4⋅0.5H2O structure can be stabilized by isovalent substitution of calcium ions for strontium ions or by aliovalent substitution of potassium and lanthanum ions for strontium ions. The compound of composition K0.25La0.25Sr0.5(SO4)⋅0.5H2O has been synthesized as an example of the stabilized SrSO4⋅0.5H2O modification. The unit cell parameters have been determined and refined. A model of the structure of SrSO4⋅0.5H2O with a statistical distribution of potassium, lanthanum, and strontium atoms over the positions of Ca atoms in the well-known СаSO4⋅0.5H2O structure has been proposed.
Rare-Earth Nitrate Complexes with Dimethylformamide
Authors: Petrichko M. I. , Karavaev I. A. , Savinkina E. V. , Grigoriev M. S. , Buzanov G. A. , Retivov V. M.
Published: April 2024

In the rare-earth element nitrate (REE)–dimethylformamide (DMF)–water systems, which can be used to obtain nanosized REE oxides by solution combustion synthesis (SCS), the formation of coordination compounds [M(H2O)3(DMF)(NO3)3]·H2O (M = La–Pr) and [M(DMF)3(NO3)3] (M = Sm–Lu, Y) has been found. Using physicochemical methods of analysis (IR spectroscopy, X-ray powder diffraction, single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, and differential scanning calorimetry), their composition has been determined and structural features have been established; thermolysis processes have been studied in a wide temperature range. It is shown that the final products of the decomposition of complex compounds are oxides of rare earth elements.
Cobalt-Doped Chalcopyrites CuGaSe2: Synthesis and Magnetic Properties
Authors: Zykin M. A. , Golodukhina S. V. , Efimov N. N.
Published: April 2024

Two series of cobalt-doped CuGa1 – xCoxSe2 and Cu1 – x/2Ga1 – x/2CoxSe2 chalcopyrites were prepared. Cobalt in part entered the chalcopyrite structure to ensure the appearance of paramagnetic properties, while in part it remained involved in cobalt selenide admixtures. High-temperature quenching forced almost all of the cobalt to enter the crystal structure in the Cu1 – x/2Ga1 – x/2CoxSe2 samples. Significant ferromagnetism appears in the Cu0.9Ga0.9Co0.2Se2 sample, which had the highest cobalt concentration, in particular at room temperature.
Thermal Transformations of Porous Anodic Aluminum Oxide Formed in Sulfuric Acid/Oxalic Acid Mixed Electrolytes
Authors: Roslyakov I. V. , Kolesnik I. V. , Belokozenko M. A. , Yapryntsev A. D. , Napolskii K. S.
Published: April 2024

Aluminum anodizing in electrolytes comprising mixtures of several acids opens way to manufacture porous films of anodic aluminum oxide (AAO) with a widely tunable structure period. Study of thermal transformations in AAO films produced in mixed electrolytes is a separate task, as a complex chemical composition of the material can give rise to some specifics in subsequent annealing. Impurity oxalate and sulfate ions were detected in the AAO produced by aluminum anodizing in sulfuric acid/oxalic acid mixed electrolytes. The sulfate weight fraction appears about one order of magnitude higher than the oxalate weight fraction, and it increases as the concentration ratio of sulfuric acid to oxalic acid in the electrolyte increases. In the same way, the crystallization temperature of amorphous AAO to a mixture of low-temperature Al2O3 polymorphs increases in response to increasing concentration ratio of sulfuric acid and oxalic acid. Thus, the component ratio in the mixed electrolyte used influences the composition and thermal transformations of AAO.
Thermodynamic Characteristics of Alkali Metal Pivalates (CH3)3CCOOM (M = Li, Na, K, Rb, Cs)
Authors: Malkerova I. P. , Belova E. V. , Kayumova D. B. , Alikhanyan A. S.
Published: April 2024

The thermodynamic properties of alkali metal pivalates (CH3)3CCOOM, where M = Li, Na, K, Rb, Cs, were studied by mass spectrometry, thermogravimetric analysis, and differential scanning calorimetry. The sublimation of the compounds was determined to be congruent. The saturated vapor contains oligomeric forms MnPivn (n = 1–6), which are dominated by dimeric and tetrameric molecules in the case of Na and K pivalates and by monomeric and dimeric molecules in the case of Rb and Cs pivalates. The partial pressures of the main components of the gas phase, their temperature dependence, and their standard enthalpies of sublimation were calculated. The enthalpies of dissociation of dimeric and tetrameric molecules were found. The standard enthalpies of formation MPiv(solid) and MPiv(gas) were estimated.
Study of Hydrolysis of Nitrile Derivatives of closo-Dodecaborate Anion (Et4N)[B12H11N≡C–R] (R = Me, Et, nPr, iPr)
Authors: Nelyubin A. V. , Klyukin I. N. , Selivanov N. A. , Bykov A. Yu. , Kubasov A. S. , Zhdanov A. P. , Zhizhin K. Yu. , Kuznetsov N. T.
Published: April 2024

The reaction of nitrile derivatives of closo-dodecaborate anion (Et4N)[B12H11N≡C–R] (R = Me, Et, nPr, iPr) with water has yielded a series of (Et4N)[B12H11NH=C(OH)–R] iminols. It has been demonstrated that the hydrolysis products are in acid–base iminol–amide equilibrium, which can be controlled by changing the pH of a medium. The reaction products have been identified by 11В, 1Н, 13С NMR, IR spectroscopy, and ESI mass spectrometry. The structures of the [B12H11(Z-NH=C(OH)nC3H7)]− and [B12H11(E-NH–C(O)nC3H7)]2− anions have been determined by X-ray single-crystal diffraction.
Effect of Supersonic Nitrogen Flow on Ceramic Material Ta4HfC5–SiC
Authors: Simonenko E. P. , Simonenko N. P. , Kolesnikov A. F. , Chaplygin A. V. , Papynov E. K. , Shichalin O. O. , Belov A. A. , Nagornov I. A. , Mokrushin A. S. , Kuznetsov N. T.
Published: April 2024

The behavior of the ceramic material Ta4HfC5-30 vol % SiC has been studied under the effect of supersonic flow of dissociated nitrogen, which is necessary to assess the potential application of these materials in oxygen-free gas environments at temperatures 1800°C. It has been found that as a result of heating the surface to ~2020°C in a few minutes there is a decrease to ~1915°C followed by a slow decrease to 188°C. This is probably due to the chemical processes occurring on the surface and the formation of an extremely rough microstructure. The ablation rate has been determined; it has been shown that neither at introduction of the sample into a high enthalpy nitrogen flow nor at sharp cooling (temperature drop to ~880°C in 9–10 s) cracking of the sample or detachment of the near-surface region has been observed. X-ray powder diffraction and Raman spectroscopy data allow us to conclude the complete removal of silicon carbide from the surface layer and the transformation of complex tantalum-hafnium carbide into the nitride.
Development of a Method for Chemical Polishing of 08Kh18N10 (AISI 304) Stainless Steel with a Nanostructured Medium
Authors: Tyulagin P. E. , Mishina E. S. , Polyakova A. S. , Murashova N. M. , Muradova A. G.
Published: April 2024

Chemical polishing of metals with nanostructured media, such as water-in-oil (w/o) microemulsions, is of interest for improving the procedure of polishing metals with concentrated acids because the etchant (acid) concentration in the microemulsions can be much lower. It was shown that w/o microemulsions in the sodium dodecyl sulfate–1-butanol–kerosene–aqueous HCl system can be used for chemical polishing of 08Kh18N10 (AISI 304) stainless steel. Regions of existence of microemulsion in this system were determined, and conditions of chemical polishing of stainless steel with a sodium dodecyl sulfate microemulsion were chosen. Conditions of cleaning of the surface of a stainless-steel sample after chemical polishing were selected so that to ensure the most complete removal of microemulsion components from the steel surface without changing the surface microrelief.
Tysonite Type Nanocrystalline Solid Solutions R1 – xScxF3 (R = La, Pr): Synthesis and Electrical Conductivity
Authors: Buchinskaya I. I. , Sorokin N. I.
Published: April 2024

The single-phase nanocrystalline R0.9Sc0.1F3 solutions (R = La, Pr) were synthesized by soft chemistry methods as transparent xerogels with the tysonite structure (space group). The ionic conductivity of ceramic samples prepared from these materials was 4.5 × 10–4 and 2.1 × 10–3 S/cm at 773 K for R = La and Pr, respectively. The activation energy of the ion transfer in ceramic samples was 0.43 (R = Pr) and 0.48 eV (R = La) in the high-temperature segment and 0.56 eV (R = Pr) in the low-temperature segment. It was shown that the isovalent replacement of La3+ (Pr3+) cations in the R0.9Sc0.1F3 tysonite solid solutions with Sc3+ leads to 3–4-fold decrease in the conductivity of the ceramic electrolytes.
Analysis of Activity Coefficients in Aqueous Solutions of Alkali Metal Bromides Based on Dielectric Properties
Authors: Shilov I. Yu. , Lyashchenko A. K.
Published: April 2024

Extended Debye–Hückel (EDH) theory was used to calculate activity coefficients in aqueous solutions of alkali-metal bromides at 298 K from experimentally determined values of their static permittivities. Calculations with non-optimized model parameters fit the nonmonotonic concentration-dependent trend of the activity coefficients and the cation radius–dependent trend of the activity coefficients. The latter is explained by hydration weakening and ion association strengthening in response to increasing cation radius in the salt series.
Anion-Exchange Resin Precipitation of Nickel Ferrite Nanopowders Modified by Plasmonic Particles
Authors: Saikova S. V. , Nemkova D. I. , Pikurova E. V. , Samoilo A. S.
Published: April 2024

Magnetic nickel ferrite/gold hybrid nanoparticles are promising materials for use in medicine, microelectronics, and plasmon-enhanced photocatalysis. The catalytic activity of a hybrid material depends on the composition, morphology, surface charge, and size of the magnetic core. In this work, anion-exchange resin coprecipitation of iron and nickel followed by heat treatment of the prepared hydroxides was used to manufacture nickel ferrite NiFe2O4 nanopowders. Fractional factorial design (FFD 27-4) was used to study the effects of reaction parameters on NiFe2O4 formation. The synthesis under the found optimal conditions yielded powders with an average grain size of 22.7 ± 1.0 nm. NiFe2O4/Au hybrid particles were manufactured by the direct reduction of gold with methionine (α-amino-γ-methylthiobutyric acid). Their formation was proved by optical spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy.
Ceramics of the Cs2O–Al2O3 System Prepared by Solid-Phase Technology and the Glycine–Nitrate Combustion Process
Authors: Fedorova A. V. , Stolyarov V. A. , Pavelina M. E. , Kolonitskii P. D. , Kirichenko S. O. , Timchuk A. V. , Stolyarova V. L.
Published: April 2024

Cs2O–Al2O3 ceramic samples containing 20 and 33 mol % cesium oxide were prepared by сeramic technique and by the glycine–nitrate combustion process. The prepared samples were identified and characterized by X-ray powder diffraction and X-ray fluorescence analyses, scanning electron microscopy, and differential thermal analysis. X-ray powder diffraction and scanning electron microscopy showed that the phase composition and surface of the samples change significantly and nonmonotonically depending on the synthetic method used and the heat treatment parameters of the batch. Optimal synthetic conditions and heat treatment parameters for preparing Cs2O–Al2O3 samples were elucidated.
Hydrochlorides and Dodecahydro-closo-dodecaborates of Amino Derivatives of 1,3,5-Triazine in the Technology of Isolation and Purification of the [B12H12]2– Anion
Authors: Saldin V. I. , Ignat’eva L. N. , Mashchenko V. A. , Sukhovei V. V. , Marchenko Yu. V.
Published: April 2024

The possibility of using salts of 2,4,6-triamine-1,3,5-triazine, 2,4-diamine-6-methyl-1,3,5-triazine, and 2,4-diamine-6-phenyl-1,3,5-triazine for isolation of the dodecahydro-closo-dodecaborate anion [B12H12]2– from aqueous solutions has been studied. Compound [2,4-(NH2)2-6-Ph-1,3,5-N3С3H]2[B12H12]⋅H2O (solubility 0.06 g in 100 g water at 17°C), promising for the precipitation of the [B12H12]2– anion, has been isolated by the metathesis reaction of moderately soluble hydrochloride [2,4-(NH2)2-6-Ph-1,3,5-N3С3H]Cl⋅H2O with sodium and potassium dodecahydro-closo-dodecaborates. A procedure has been developed for the decomposition of [2,4-(NH2)2-6-Ph-1,3,5-N3С3H]2[B12H12]⋅H2O with ammonium hydroxide to obtain soluble salts of the [B12H12]2– anion
Nonempirical Modeling of Interactions of Fe2O2 and Fe2O4 Clusters with H2 and O2 Molecules
Authors: Bozhenko K. V. , Utenyshev A. N. , Gutsev L. G. , Gutsev G. L. , Aldoshin S. M.
Published: April 2024

Quantum-chemical calculations of the geometric and electronic structures of compounds formed by the interaction of Fe2O2 and Fe2O4 clusters with diatomic H2 and O2 molecules in the gas phase have been performed by the density functional theory method in the generalized gradient approximation using the triple-zeta basis set. The trends in changes in the binding energy of H2 and O2 molecules with Fe2O2 and Fe2O4 clusters depending on the number of oxygen atoms have been found. It has been demonstrated that in two of the four reactions considered, the total spins of the initial reagents and final products do not coincide, that is, spin relaxation occurs. It has been concluded that nanoparticles based on Fe2O4 clusters can be used as sensors for detecting H2 and O2 molecules.