One of the most interesting natural materials with a rich composition of various elements, including rare earth elements, is shungite. Inductively coupled plasma mass spectrometry (ICP-MS) was successfully used to detect metals in various ores, which has high sensitivity for determining elements even in trace amounts. ICP-MS analysis revealed 53 elements in shungite, the total content of which in the original sample did not exceed 3 wt%. The effect of preliminary treatment with various solvents (extraction) on the isolation and determination of the maximum content of elements in shungite was considered. The effect of parameters such as the nature of the extractant, sample mass, extraction time, and preliminary heat treatment on the total content of elements in the original shungite sample was studied. It was found that extraction with water, methanol, potassium hydroxide, or hydrochloric acid significantly increased the total detected content of elements in shungite; the total content of elements can reach 20 wt%. Data analysis showed that the detectable content of elements in a 0.2 g sample was higher than in a 0.5 g sample, and an increase in extraction time led to an increase in the detectable amounts of metals. Recommendations were given on sample preparation to achieve effective extraction and determination of metals by the ICP-MS method. The most comprehensive information on the content of elements in shungite can be obtained by extracting the sample with methanol.

A method for preparing a peat-shungite sorbent with the addition of a potassium-phosphate buffer solution for neutralizing hydrazine derivatives is proposed. The peat-shungite sorbent is characterized by ease of manufacture, relative cheapness, in addition, the main components are of natural origin. Sorbents with different shungite contents (25, 34, 42 and 50 wt.

The kinetics of N-(monohydrofullerenyl)-l-alanine and N-(monohydrofullerenyl)-D-alanine consumption during interaction with alkylperoxy radicals in aqueous colloidal solutions were recorded. The covalent attachment of radicals to the fullerene 'core' was confirmed by IR spectroscopy. It was found that the antiradical activity of fullerene derivatives initially quickly declines but does not further tend to zero, remaining at a significant level for a longtime, which is probably due to another inhibition mechanism realized through free radical adsorption on nanoparticles followed by recombination.

The study of the physicochemical (including adsorption) properties of nanodiamond requires the possibility of reproducible generation of the carbon surface of an individual particle without metal impurities of unknown composition. This kind of surface can be obtained through an additional deep cleaning of a commercially available sample. This article is dedicated to the study of the composition of non-combustible impurities of detonation nanodiamond powder. Using inductively coupled plasma mass spectrometry, iron and titanium were identified as the main metal components of the unburned residue, and the presence of Cr, Ni, Zr, As, and Sb was qualitatively established. The expected composition of the main molecular ions formed on the surface of the unburned residue in the course of laser desorption/ionisation mass spectrometry was presented. Based on the results of mass spectrometry analysis, a method of two-stage chemical treatment of detonation nanodiamond powder was proposed, which allowed reducing the mass fraction of non-combustible impurities during annealing in air from 2.0 to 0.1%.

A three-component condensation of 2-unsubstituted imidazole N-oxides, 3-ketonitriles, and aldehydes is described. The reaction proceeds via sequential Knoevenagel condensation/Michael addition under mild, catalyst-free conditions with various substrates. Furthermore, the corresponding 2-functionalized imidazole N-oxides can be further dehydrated to (Z)-2-aroyl-3-(1H-imidazol-2-yl)-acrylonitriles, which may also be directly prepared by changing the reaction conditions as a cascade of Knoevenagel condensation/Michael addition/dehydration.

To study the physicochemical (including adsorption) properties of nanodiamond, it is necessary to reproducibly obtain a carbon surface of an individual particle without metallic impurities of an unknown composition. Such a surface can be obtained through an additional procedure of the deep purification of a commercially available sample. This work is devoted to a study of the composition of non-combustible impurities of detonation diamond nanopowder. Using inductively coupled plasma mass spectrometry, iron and titanium are identified as the main metallic components of the non-combustible residue, the presence of Cr, Ni, Zr, As, and Sb is qualitatively established. The expected composition of the main molecular ions formed on the surface of the non-combustible residue under laser desorption/ionization mass spectrometry conditions is presented. Based on the results of the mass spectrometric analysis, a version of two-stage chemical treatment of detonation diamond nanopowder is proposed, which made it possible to reduce the mass fraction of non-combustible impurities during annealing in air from 2.0 to 0.1

The purpose of this work was to study the composition of cluster ions in samples containing sodium stannate and tin(II) chloride. It has been shown that the composition of mass spectra is influenced by such parameters as the laser radiation energy and the substance content in the sample being studied. Conditions for preparing samples and recording mass spectra using these parameters were optimized. Presumptive identification of peaks in the recorded mass spectra was carried out. It has been shown that many of the ion peaks observed in the mass spectra may correspond to clusters containing tin. In the mass spectra of sodium stannate, ions of the general composition SnxOyNazHm were detected, in which the number of tin atoms reaches eight, and the maximum ion mass-to-charge ratio (m/z) is 1100. In the mass spectra of tin(II) chloride, there are ions of the general composition SnxOyHmClp and SnxCly, where the number of tin atoms reaches 4, and the highest m/z value is 1000.

This paper presents data on the mass spectrometric study of amino acids and dipeptides under electrospray ionization conditions. It is shown that the formation of a molecular ion depends not only on the nature of the ionizable compound, but also on its concentration in the solution under study. When registering mass spectra, the decay products of the studied molecules, as well as the products of their interaction with each other, were detected. It was shown that the nature of the mass spectrum can change depending on the concentration of the test compound. The main conclusions about the physicochemistry of the interaction of molecules in solution with each other are given. It is shown that the intensity of destruction and association of various molecules depends on the concentration of the substance in the solution and the geometry of the molecules.

The authors describe a way of detecting nitro and amino compounds using a mass spectrometer with laser desorption/ionization. This allows analysis of nitro- and amino compounds from a metal surface without sample preparation at levels of up to 5 ng/cm2 relative to paracetamol. Sensitivity is at the level of modern means of analysis, and the procedure is simple and fast. It is also universal and can be modified to search for other nitro- and amino compounds. Pointwise quantitative analysis can be done using an external standard. The dynamic range is 1.5–2 orders of magnitude. The technique can be used to analyze metal surfaces for nitro-paint residues and traces of explosive compounds.

В работе описан метод масс-спектрометрического детектирования нитро- и аминосоединений с использованием масс-спектрометра с лазерной десорбцией/ионизацией. Показано, что метод дает возможность анализа нитро- и аминосоединений с металлической поверхности без пробоподготовки на уровне до 5 нг/см 2 по парацетамолу. Чувствительность находится на уровне современных методов анализа, а также метод прост в исполнении и экспрессен. Показано также, что метод универсален и может быть модифицирован под поиск других нитро- и аминосоединений. Также возможно проведение поточечного количественного анализа с использованием внешнего стандарта. Динамический диапазон метода – 1.5–2 порядка концентрации. В заключение показано, что предлагаемый метод может быть использован для анализа металлических поверхностей на остатки нитрокраски и следов взрывчатых соединений.

The results of quantitative analysis of widely used surface samples are shown. Corrosion damage to copper and steel surfaces can be analyzed quantitatively using cobalt chloride as the internal standard. The study also demonstrates the feasibility of comparative quantitative analysis of blue ink using methylene blue homologues as standards. When conducting quantitative analysis on surfaces with inhomogeneous morphology, it has been observed that direct analysis is not possible because of uneven ionization of the sample. It has been found that when analyzing such surfaces, it is necessary to exclude points with a low signal-to-noise ratio from consideration. The work highlights the extensive possibilities of utilizing quantitative analysis in mass spectrometric visualization of the surface. The work is aimed at demonstrating the capabilities of the laser desorption mass spectrometric method for analyzing the surfaces of various materials, which will make this method universal for searching for a wide range of contaminants on the surface of materials of various nature.

Thin-layer chromatography and matrix-assisted desorption/ionization are used in this work to analyze and to separate monosubstituted and disubstituted nitrobenzoic acids. Parameters of chromatographic process were calculated due to the possibility of visualization of the mass spectrometric method. The data indicate that the mobility coefficients for meta-nitrobenzoic and 3,5-dinitrobenzoic acids differ by approximately two times, and the separation factor is 0.67. It was found that the thickness of a stationary phase (silica gel) of a factory plate for thin-layer chromatography should be decreased to increase the sensitivity of the analysis. It is recommended, therefore, to mechanically remove a small layer of silica gel before starting the analysis. Silica gel acts as a matrix during mass spectroscopic analysis.

Changes in electron work function (EWF) φ̅ = f(τ ) during the separation of Si(100) single-crystal silicon wafers into smaller samples (scribing operation) have been studied by the method of kinetic curves of EWF. The observed effect can be attributed to the sorption of water vapor on the Si(100) surface. The Helmholtz formula has been applied to estimate the amount of water absorbed by the samples, causing a change in the EWF. To determine the localization of sorbed water, we have used the method of layer-by-layer etching of the surface of Si(100) samples using low-temperature SF6-plasma. It has been shown that with a decrease in the size (area) of the samples, the size effect of the EWF takes place. For a whole plate (with an area of 80 cm2) is characterized by the EWF value close to its reference value ( φ̅≈ 5.0 eV), while for small samples ( 1 cm2), this value decreases to 4.5 eV, which indicates a significant water content in the samples ( 0.3 × 1015 molecules cm–2). The data on sample etching by plasma have showed that water is unevenly distributed over the thickness of the sample, and is mainly concentrated in its deeper layers, not changed by mechanical processing (grinding and polishing). The results obtained are consistent with the theory of the secondary structure of a crystal (SSC), according to which crystalline solids have regular gaps (“T-space”) with a size of “1 atomic layer,” in which impurity transfer processes occur. Apparently, chemisorption of water takes place in the micropores of the T-space, which leads to size effects on Si(100).

A new synthetic protocol for the preparation of oxazole N-oxides in the form of stable boron trifluoride complexes has been developed. It is based on the condensation of alpha-diketone monooximes with an appropriate aldehyde component in the presence of an equimolar amount of boron trifluoride. The method opens access to a broad scope of derivatives including previously unknown 2-unsubstituted oxazole N-oxides. Its abilities were demonstrated via the synthesis of 25 diverse oxazole derivatives in 14-89 % yields.

The possibilities of mass spectrometric visualization in new areas of research are considered. It is shown that surface mass spectrometry can be used to study structural materials and monitor surfaces for corrosion damage, process contamination, and damage. The possibility of studying non-metallic materials is shown for the first time. It is found that studying the low molecular weight part of polymer films helps to detect technological impurities and irreversible deformation of the film surface. It is established this can be used to authenticate handwritten documents, make corrections to them, and successfully compete with the classical means of such research.

A study is performed of the SALDI mass-spectrometric imaging of surfaces of structural materials. The search for the best marker substance is described. It is shown that nickel and copper salts cannot be used to solve the problem. Good signal reproducibility over a surface is shown by silver chloride, bromide, and silver iodide, the mass spectra of which are a large set of cluster ion peaks. Silver halides have a high ionization cross section as well. The best reproducibility is found for nitrobenzoic acids, due to the stable aromatic cycle in the molecule and the procedure’s softness of ionization. It is also shown that the most uniform distribution of a marker substance over a surface is obtained by immersing the sample in its solution. Single drops and sprays can also be applied with some modifications.

The possibility of analyzing the amount of chlorine on the surface of stainless steel is investigated and a method for obtaining reproducible results by evening or eliminating the physicochemical features of surface ionization of a calibrant crystallized from a solution is described. It is shown that the main factor influencing the quality of calibration and analysis is the shape of the resulting drop and its size. It was also found that integrating the analytical signal over the entire drop is the most appropriate method for calibration and obtaining the most reproducible results. The main factors influencing the physicochemical characteristics of ionization and, as a consequence, the reproducibility of the calibration data are presented. It has been established that the method of calibration with the integration of a signal by a drop can be effectively used in the analysis of ultra-small amounts of chlorine on the surface of stainless steel in the range from 0.12 to 120 pmol/mm 2 . In this case, the proposed approach eliminates the physicochemical factors affecting the ionization efficiency, which limit the use of surface laser desorption/ionization for quantitative analysis.

The interest in magnesium-based materials is promoted by their biocompatibility, their bioresorbability, and their recently discovered antibacterial potential. Until now, the widespread use of magnesium alloys in different corrosive environments was inhibited by their weakly controllable degradation rate and poorly understood microbiologically induced corrosion behavior. To better understand the degradation and usability of magnesium-based alloys, in this study we have fabricated superhydrophobic coatings on a magnesium-based alloy, and analyzed the behavior of this alloy in bacterial dispersions of Pseudomonas aeruginosa and Klebsiella pneumoniae cells in phosphate-buffered saline. It was shown that the immersion of such coatings in bacterial dispersions causes notable changes in the morphology of the samples, dependent on the bacterial dispersion composition and the type of bacterial strain. The interaction of the superhydrophobic coatings with the bacterial dispersion caused the formation of biofilms and sodium polyphosphate films, which provided enhanced barrier properties in magnesium dissolution and hence in dispersion medium alkalization, eventually leading to the inhibition of magnesium substrate degradation. The electrochemical data obtained for superhydrophobic samples in continuous contact with corrosive bacterial dispersions for 48 h indicated a high level of anticorrosion protection.

Работа посвящена изучению места современных масс-спектрометрических методов в области исследования полимеров. Исследованы вопросы развития методов и показано, что практически до конца ХХ века масс-спектрометрия применялась для изучения полимеров крайне ограниченно из-за нелетучести полимеров. Рассмотрен метод пиролитической масс-спектрометрии как наиболее распространённый для определения молекулярно-массового распределения, определения концевых групп и других общих задач. Также описаны более современные методы “мягкой” ионизации, позволяющие ионизировать полимеры из конденсированного состояния с одновременной десорбцией в газовую фазу. Обзор литературы показал, что подобные методы практически полностью вытеснили или значительно дополнили инструментарий исследователя полимерных материалов. В работе со ссылками на литературу описаны матрично-активированная лазерная десорбция/ионизация (MALDI), полевая десорбция (FD), бомбардировка быстрыми атомами (SIMS), ионизация электораспылением (ESI). Также в качестве более классического метода описана пиролитическая масс-спектрометрия с прямым вводом и в сочетании с газохроматографическим разделением. Показано, что масс-спектрометрия наиболее универсальный и чувствительный метод при любых задачах в области анализа и исследования полимерных материалов.