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Liquid chromatography and MALDI mass spectrometry have been employed to study the effect of 1,1-dimethylhydrazine and its acetone hydrazone on peptide composition of hemolymph of Galleria mellonella caterpillar larvae. It has been found that the following components arise in the hemolymph: induced low-molecular-mass peptide products with masses of 1–3 kDa, fragments and methylated modifications of previously-known antibacterial peptides of Galleria mellonella, as well as six unknown peptides that exhibit bactericidal activity with respect to Gram-negative bacteria Escherichia coli.

It is known that highly charged droplets formed in the course of electrospraying disintegrate into a number of smaller droplets. The criteria for the instability and disintegration of conducting liquid droplets in the course of electrospraying have been considered in this article. Some forms of the perturbation of a spherical liquid droplet have been shown for the case when the Rayleigh stability criterion is exceeded. The analysis of the development of charge instability has shown that a quasi-stable state may exist during the disintegration of a liquid droplet in the region of instability according to the Rayleigh criterion.

We propose a new approach to assessing the contamination of tea, coffee, cocoa, and vegetable oils with F-, Cl-, Br- and S-containing organic pesticides and other hazardous anthropogenic and natural compounds at a trace level. The approach ensures the rapid screening of test samples for the total concentration of all halogen and sulfur organic compounds present in the samples. Sample preparation is excluded. The procedure is based on the direct high-temperature oxidative conversion of a test sample under oxygen; the absorption of inorganic salts present in the sample in a reactor; the absorption of the conversion products of organic compounds of the sample, including the analyzed ones, by deionized water with the formation of F–, Cl–, Br– and SO $$_{4}^{{2 - }}$$ anions; and their determination in the absorbate by ion chromatography. This approach ensures the simultaneously reliable determination of all volatile, medium-volatile, and nonvolatile organohalogen and organosulfur compounds present in one sample and, thereby, improves the reliability of detection by eliminating their losses during the analysis.

Abstract The construction materials that contacted with unsymmetrical dimethylhydrazine and the desorption solutions obtained when treating the contaminated surface of metals and alloys with water and reagents were studied by chromatography and mass spectrometry. Neutralization of unsymmetrical dimethylhydrazine was studied using ozone and shungite. Ozonation makes it possible to destroy the toxicant molecules chemically and physically adsorbed on the surface of metal constructions, due to which they can be reused and utilized. Shungite effectively adsorbs and catalytically decomposes not only unsymmetrical dimethylhydrazine and its transformation products, but also oligomer compounds formed during the storage of hydrazine fuel. Ozonation of spent shungite can increase the efficiency of destructive processes and completeness of its regeneration.

Procedures for qualitative and quantitative analysis of microimpurities of alkylhydrazines and their transformation products in hydrocarbon rocket propellants Naftil, Syntin, and Detsilin by gas and liquid chromatography with on-line and off-line mass-spectrometric detection were developed. Reliable detection of an unsymmetrical dimethylhydrazine impurity in Naftil multicomponent propellant and in its mixtures with other hydrocarbon propellants is possible in the form of thiosemicarbazides by reversed-phase high-performance liquid chromatography and matrix-assisted laser desorption/ionization mass spectrometry.

Powders of boron, magnesium and tungsten before and after mechanochemical activation are studied via laser desorption/ionization. It is found that the activation process removes low molecular weight hydrocarbon impurities and high molecular weight clusters of oxides and hydroxides. It is shown that this technique allows determination of clusters in a wide range of masses.

The liquid fraction of tire pyrolysis products was comprehensively analyzed by gas chromatography–mass spectrometry and two-dimensional gas chromatography. The direct (nonpolar–polar) и and inverse (polar–nonpolar) column combinations were used. The inverse combination allows efficient separation of alkanes and alkenes. Aliphatic hydrocarbons constitute no more than 24 wt % of the liquid fraction, with the remainder being aromatic, mainly monoaromatic, compounds. The sulfur content of the liquid fraction is about 0.7 wt %; sulfur is mainly present in the form of thiophene derivatives.

Ionized products of desorption of thiosemicarbazides from a steel target surface before and after deposition of solid solutions of thiosemicarbazides in organic matrices (nicotinic acid, α-cyano-4-hydroxycinnamic acid, 2,5-dihydroxybenzoic acid, and dithranol) onto it have been studied by mass spectrometry. 2,5-Dihydroxybenzoic acid has been revealed to be a universal matrix for studying the synthesized thiosemicarbazides under the conditions of matrix-assisted laser desorption/ionization. Its use leads to a 100-fold decrease in the detection limit of thiosemicarbazides as compared with α-cyano-4-hydroxycinnamic acid. Investigations of the decomposition of metastable protonated thiosemicarbazide molecules accelerated in the ion-source region have resulted in suggesting the mechanisms of their fragmentation and ionization.

Powders of metals (magnesium and tungsten) and nonmetals (boron and silicon) are used to analyze Fluralit-4 Teflon (polytetrafluoroethylene) powder by means of surface-activated laser desorption/ionization. It is shown that this technique allows the degree of Teflon degradation to be determined. It is established that when silicon powder is used as a matrix, it is possible to register both low molecular weight products of the degradation of Teflon and its oligomeric products in the range of up to 1400 Da. The Teflon mass spectra contain two series of ions: one for saturated components and one for unsaturated components.

SILP (supporting ionic liquid phase) catalysts for peroxide thiophene oxidation were obtained on silica gel, they included imidazole cations with sulfonic acid group and phosphotungstate anions. The composition of the active phase and the surface structure of the catalysts are characterized by a set of modern physicochemical methods, including mass spectrometry using the SALDI technique. It was found that the organic cation structure affects the stability of heteropolyanions, decomposition processes in the SILP and the catalytic properties of the samples. SILP catalysts are effective in desulfurization of the diesel fraction and provide fuel with an S content of less than 10 ppm.

A methodology is proposed for the highly selective, sensitive, and reliable determination of the total concentration of halogen and sulfur organic compounds in vegetable oils in the presence of inorganic salts, based on the direct high-temperature conversion of an oil sample in a stream of pure oxygen, absorption of inorganic salts in a reactor, absorption of the products of analyte conversion with deionized water to form F–, Cl–, Br–, and S $${\text{O}}_{4}^{{2 - }}$$ anions, and their determination in the absorbate by ion chromatography. An increase in the reliability of the determination of F–, Cl–, and Br– anions is provided by combining the registration of retention times in the direct determination of anions with an analysis of the flow of the same absorbate after the selective removal of F–, Cl–, and Br– anions (together) using corresponding adsorption columns packed with cation exchangers R–Al3+ (for F–) and R–Ag+ (for Cl– and Br–) (possibility of distortion of the determination result of these anions due to potentially coeluted components is excluded). Using the proposed methodology, the total concentration of halogen and sulfur organic compounds is determined in samples of vegetable oils of varying degrees of purity. It ranged from 2 × 10–6 to 6.0 × 10–2% (in terms of element), depending on the sample and element, at a sample volume of 1 μL. A possibility of increasing sample volume by up to 15 times and lowering the limits of detection to 10–7% (in terms of element) is shown.

The neutralization of toxic hydrazine fuel accidents and spills is an urgent task of protecting the biosphere. The effectiveness of using shungite for sorption and catalytic destruction of unsymmetric dimethylhydrazine and its transformation products in the environment has been established. The interaction of shungite with unsymmetric dimethylhydrazine that has fallen into water and soil is investigated. The composition of the products of oxidative transformation and desorption was identified, and the kinetics of changes in their concentration on the surface of various sorbents was studied depending on the state of the environment and temperature, soil composition and the presence of shungite. According to the results, a technology has been created that allows efficiently and environmentally sound elimination of spills of hydrazine fuel. The reliability of this technology is based on the results of chromatographic and mass spectral methods for monitoring the neutralization degree of ecotoxicants.

A method for quantitation of exogenous cis fatty acids in the presence of exogenous cis and trans fatty acids that does not require time-consuming and tedious chromatographic separation is described. In it, we use an inhibitor that blocks Elovl6, an enzyme involved in fatty acid synthesis in vivo. Samples prepared in the absence or presence of the inhibitor are sequentially analyzed by liquid chromatography with mass spectrometric detection. The developed method is used for analyzing endogenous cis fatty acids synthesized in cancer cells.

A technique of molecular statistical calculations, developed and improved with the active participation of workers at the Institute of Physical Chemistry and Electrochemistry, allows the accurate estimation of the chromatographic retention of analytes. The resulting version of molecular statistical method (with regard to conformational non-rigidity) is used to predict the values of alkylbenzene retention under conditions of gas adsorption chromatography. The accuracy of estimating the retention indices is compared to results from current machine learning approaches of predicting retention (for gas-liquid chromatography). The effectiveness of separating structural hydrocarbon isomers on different columns is also compared.

This work is aimed at obtaining mixed cluster ions of amino acids with copper salts using soft ionization methods. We have shown that amino acid molecules are capable of forming aggregates stabilized by d-metals. In particular, such clusters can form in the presence of silver salts. In the present work, it is revealed that the largest cluster ions can be obtained using the electrospray ionization method. It is found that, upon ionization of amino acids (leucine, alanine, proline, tyrosine, and tryptophan) in the presence of copper salts, cluster associates with a mass of up to 1500 Da are formed. It is also found that the formation of cluster ions strongly depends on the nature of the amino acid and polarity of the charge in the cluster.

The physicochemical properties of artificial hybrid inorganic-organic material based on highly dispersed porous shungite and silver nanoparticles are investigated via energy dispersive X-ray microanalysis and surface activated spectrometry with laser desorption/ionization. Silver is found to be firmly secured on the shungite surface, forming clusters with shungite carbon. The hybrid material is well wetted by water and forms stable nanodispersions in water.

A comparative study of adsorption of isomeric alkylbenzenes, alkylphenols, and alkanes on carbon sorbents from a gas and a liquid phase using an extended variant of molecular statistics calculations is carried out. In simulation, conformational non-rigidity of molecules is taken into account. This method is shown to satisfactorily estimate proportions between the adsorption characteristics for isomers of hydrocarbons adsorbed on graphitized thermal carbon black from a gas phase. In the case of adsorption from a liquid phase on porous graphitized carbon, additionally, the effect of a solvent and polarizability of the sorbent surface by charged sites of a sorbate molecule are considered. It is demonstrated that, for correct prediction of the ratio between the Henry constants for adsorption of isomers of alkylphenols and alkylbenzenes from solutions, it is necessary to consider both these factors.

Hybrid imidazolium SILCs (supported ionic liquid catalysts) were prepared on the basis of H3PMo12O40 and H3PW12O40, grafted to mesoporous silicas of two types: silica gel and silochrome. They are active and stable catalysts for the peroxide oxidation of thiophene and thioanisole and oxidative desulfurization of diesel fuel. The structure of heteropolyanions on the surface depends on the silica nature and the Im: HPA ratio; a decrease in this ratio leads to their partial destruction. The specific activity (TOF) for the conversion of thiophene, which is the most oxidation-resistant sulfur-containing heterocycle, was 80–100 h−1 for W derivatives and 40–47 h−1 for Mo derivatives, which exceeds the values known from the literature. The use of W catalysts reduces the sulfur content in diesel fuel from 1080 to 7–8 ppm.

The identification features of symmetric and nonsymmetric diaryl telluroxides via chromatography/mass spectrometry with electrospray ionization (HPLC/MS-ESI) are studied in the present work. Diaryl telluroxides exposed to ESI are shown to give rise to the formation of dimer ions and associate ions with the mobile phase components. Moreover, the influence of analyte concentration in the solution and the injection volume is found to impact the chromatography/mass spectrometry data.

Investigation of the physical chemistry of adsorption by carbon sorbents is a very important task from both theoretical and practical points of view. The thermodynamics of adsorption is affected by defects on the sorbent surface, including oxygen-containing functional groups. In this work, adsorption of a series of aromatic and aliphatic amines and nitriles by the surface of graphitized thermal carbon black is simulated using the Monte Carlo method. The results of calculations are compared to the experimental data. The cases of isolated and paired arrangement of functional groups are considered, and regularities of interaction between different classes of nitrogen-containing compounds and such defects are revealed. On the basis of comparison with the experimental data, assumptions about the presence and distribution of hydroxyls on the surface of graphitized thermal carbon black are made.

A complex analysis of the crumbed rubber produced by the explosive circulation method has been performed by the methods of AFM, X-ray diffraction, gas chromatography, mass spectrometry, and gel-permeation chromatography (GPC). The results of the small- and wide-angle X-ray diffraction study have revealed an amorphous structure of the samples without supramolecular ordering at a distance scale of ~1–40 nm. Globular formations of a size of 5–20 nm on the crumb surface combined into clusters of various shapes and sizes in the range 100–1000 nm have been found by means of the AFM method. Individual nanoglobules and small and large clusters of these nanoglobules appeared to be randomly covering the surface of the examined samples. It has been established that the nanoglobules partially consist of saturated and unsaturated hydrocarbons of low-molecular weight, which belonging to classes of linear, cyclic, and aromatic compounds. Most of the nanoglobules are represented by oligomeric products having 3–5 units, as well as compounds of higher molecular weight. All of the above compounds provide better adhesion of the regenerate to different matrices than that produced by other methods. The composition of the nanoscaled globules includes secondary products of reactions of low-molecular hydrocarbons formed from rubber tires at their explosive circulation grinding.

The interaction of ethyl-, allyl-, and phenyldimethylthiosemicarbazide with silica gel with grafted cyanopropyl groups has been studied in aqueous and organic solutions under the conditions of normal- and reversed-phase liquid chromatography. The influence of liquid phase composition and temperature on the separation of reaction mixtures of thiosemicarbazides and isothiocyanates in a Zorbax-CN column has been investigated. The elution order of ethyl-, allyl-, and phenyldimethylthiosemicarbazide has been found to be the same when using their aqueous and organic solutions. The selectivities of silica gels with grafted cyanopropyl and octadecyl groups have been compared. Thermodynamic parameters have been determined for the adsorption of the thiosemicarbazides on the modified silica gels.

The thermodynamics of adsorption of some substituted 1,3,4-oxadiazoles and 1,2,4,5-tetrazines from water–acetonitrile solutions with acetonitrile volume fraction varying within a range of 0.35–0.90 on chemically modified Luna C18 and Discovery C18 silica gels has been studied within a temperature range of 313.15–333.15 K. The thermodynamic characteristics of the adsorption of these compounds on Luna C18 and Discovery C18 silica gels have been determined as depending on solution composition. In the case of Discovery C18, the character of the dependences of different thermodynamic characteristics of the adsorption on liquid phase composition is similar to that of the corresponding dependences previously observed for modified Ascentis®Phenyl silica gel. A similarity has also been found for the dependences of the thermodynamic characteristics of the adsorption on Luna C18 and modified Diasfer-110-C18 silica gel studied previously. The mechanism of the liquid-phase adsorption of 1,3,4-oxadiazoles and 1,2,4,5-tetrazines on Luna C18 is changed within a range of acetonitrile volume fractions of 0.60–0.75, as it is in the case of Diasfer-110-C18. At acetonitrile volume fractions of higher than 0.75, the studied heterocycles are adsorbed on Luna C18 surface dynamically modified with acetonitrile without a direct interaction with the grafted layer of the chemically modified silica gel. At the same time, the mechanism of their adsorption on Discovery C18 remains unchanged while acetonitrile concentration is increased in the liquid phase.

The gas chromatographic properties of the porous methacrylate polymers, copolymers of 2,3-epoxypropyl methacrylate (2,3-EPMA) and ethylenedimethacrylate (EDMA), modified by silver nanoparticles were studied. The modification of the initial methacrylate copolymer by silver nanoparticles almost does not change the ability of the copolymer to dispersion interaction but results in an increase in polarity and enhances the possibility of specific interactions to occur. The aminated copolymer (copolymer of 2,3-EPMA and EDMA modified by diethylenetriamine using the reaction at the epoxy group) modified by silver nanoparticles demonstrates a higher ability to dispersion interactions and a lower polarity. Possibly, the sorption of silver particles on amino groups of the polymer is a reason for decreasing polarity of the polymer.

The influence of the surface chemistry of nonpolar sorbents (silica gel C18 and porous graphitized carbon), temperature, and liquid phase composition on the parameters of chromatographic retention of S,N-derivatives of 1,1-dimethylhydrazine (thiosemicarbazides) has been studied under the conditions of liquid chromatography. Experimental data have been compared with the results of preliminary estimates obtained for the adsorption characteristics of thiosemicarbazides using a molecular-statistical approache and determination of lipophility factor. Satisfactory agreement has been revealed between the experimental data and theoretical predictions. It has been shown that mixtures of ethyl-, allyl-, and phenylthiosemicarbazide are most efficiently separated by chromatography with the use of porous graphitized carbon packed into a Hypercarb column. The selectivity of this sorbent is 1.5 times higher than that of octadecyl silica gel packed into a Zorbax Eclipse XDB C18 column.

Adsorption of some 1,3,4-oxadiazoles and 1,2,4,5-tetrazines from water–acetonitrile solutions on Luna C18 and Discovery C18 silica gels with grafted octadecyl groups has been studied in a wide range of compositions at temperatures of 313.15–333.15 K. The comparative analysis of the liquid-phase adsorption of the heterocycles has revealed a number of differences between the mechanisms of binding molecules of the studied compounds by the surfaces of these octadecyl-derivatives of silica gel. The log–log dependences of the retention factor on the molar fraction of acetonitrile in the solutions are strictly linear only for adsorption on Luna C18 silica gel, which is characterized by an increased hydrophobicity. For the adsorption of the studied heterocycles on Discovery C18 silica gel, the concentration dependences of the retention at low and high acetonitrile concentrations in the solution are described by quadratic functions and characterized by higher retention values as compared with those for the linear dependence because of the lower hydrophobicity of this silica gel. It has been found that the surface layer of Luna C18 modified silica gel is enriched with acetonitrile molecules to a higher extent than the surface layer of Discovery C18 silica gel. It has been shown that one adsorbed molecule of 1,3,4-oxadiazoles and 1,2,4,5-tetrazines displaces three and two molecules of pre-adsorbed acetonitrile from the surfaces of Luna C18 and Discovery C18 silica gels, respectively. Linear correlation equations have been proposed for calculating the retention of the studied heterocycles on Luna C18 and Discovery C18 silica gels from mobile phases of arbitrary compositions at different temperatures of chromatographic columns.

The influence of an initial form of a macroporous highly basic anion exchanger with a low degree of cross-linking on the sorption of vanillin has been studied and the effect of experimental factors on the shape of the output curve for the sorption has been determined. By varying different process parameters upon hydroxybenzaldehyde absorption by an OH-form AV-17-2P anion exchanger, it has been shown that the working and the total capacities of the sorbent depend on the concentration and flow rate of an initial solution in the studied range of these parameters: under dynamic conditions, the sorption capacity of the anion exchanger decreases as temperature is elevated. It has been found that the macroporous highly basic sorbent with a low degree of cross-linking may also be used for extraction of some other phenolic compounds under dynamic conditions.

High-performance liquid chromatography is used under near-equilibrium conditions to study the adsorption of isomeric dipyridyls and their derivatives from water–acetonitrile, water–methanol, and water–isopropanol solutions onto Hypercarb™ graphite-like carbon material in the region of Henry’s law. Hypercarb™ graphite-like carbon material exhibits high adsorption selectivity in separating the investigated isomeric dipyridyl and its derivatives. It is shown that the possibility of forming strong intramolecular C–H–N'-hydrogen bonds in a molecule of 2,2'-dipyridyl or its derivatives strengthens the adsorption bonding of adsorbate molecules and the surface of the graphite-like material due to stabilization of their planar conformation. Destabilizing this intramolecular hydrogen bond by adding substituents in different positions of the pyridine rings enhances the specific intermolecular interaction between adsorbate molecules and the solvent’s components and distorts the planar conformation of dipyridyls, weakening their retention on the Hypercarb™ material. Positive adsorption from the water–organic medium on the carbon adsorbent is observed for all of the investigated dipyridyls, with the exception of 2,2'-dipyridyl-N,N '-dioxide, which is adsorbed weaker than the solvent components. Anomalous medium–property dependences are found for the thermodynamic characteristics of the adsorption of dipyridyls on porous graphitic carbon, and are attributed to the predominance of adsorbate–adsorbent π–π interactions over hydrophobic ones and the resolvation of adsorbate molecules with acetonitrile in proportion to lowering the content of water in the bulk solution.

Isomeric compounds are characterized, on the one hand, by the proximity of the main physicochemical characteristics, including mass, NMR and IR spectra, and on the other hand, by significant differences in properties essential for a human being, for example, reactivity and toxicity. Virtually all known physicochemical methods of analysis are used to study and determine isomers; chromatography–mass spectrometry is among the most effective ones. Mass spectrometric identification includes library search, building the structure of a molecule based on fragmentation patterns for various classes of organic substances, and the use of special methods of ionization, yielding information about the structure of molecules. Chromatographic separation enables the identification of isomeric compounds with identical mass spectra. Information about the presence of specific isomers in their complex mixtures is necessary for making serious arbitral decisions in forensic science, toxicology, or doping analysis. The review discusses examples of using chromatography–mass spectrometry for isomer-specific analysis in antidoping control.

The adsorption of polychlorinated aromatic hydrocarbons on graphitized thermal carbon black was simulated by a molecular-statistical method. The results of calculations were compared with data on chromatographic retention under gas chromatography conditions. A version that took into account the conformational flexibility of molecules was used for polychlorinated biphenyls. Different computational chemistry methods (classical molecular dynamics and semiempirical quantum methods) for evaluating the internal energy of a molecule were considered. It was found that the use of a molecular-statistical method and the AM1 semiempirical method for estimating the internal energy of molecules makes it possible to correctly predict the order of elution of isomeric dichlorobiphenyls. It was demonstrated that this approach can be used to confirm the assignment of peaks in a chromatogram to particular isomers.

S,N-derivatives of alkylhydrazines, including 1,1-dimethylhydrazine, have been synthesized for the quantitative analysis of trace impurities of hydrazines in environmental objects. The molecular-statistical method has been used to calculate the thermodynamic characteristics of their adsorption on graphitic thermal carbon black. The dependences of the thermodynamic functions of S,N-derivatives of alkylhydrazines on their molecular mass and stereochemical features of hydrocarbon radicals have been found. The results have been compared with experimental data obtained by liquid chromatography when studying the interaction of S,N-derivatives of 1,1-dimethylhydrazine with Hypercarb graphitic carbon sorbent.

Mass spectrometry and chromatography are used to study the decomposition products of Teflon mixtures of the “Fluralite-4” brand with magnesium, tungsten, and titanium, activated by mechanochemistry. The temperature and energy parameters of water and carbon dioxide release are determined, volatile products of Teflon depolymerization are detected and identified, i.e., tetrafluoroethylene, trifluoromethylene, trifluoroethylene. It is shown that the introduction of metal mixtures in the composition significantly affects the decomposition processes of Teflon.

Size-exclusion chromatography has been employed to determine the sizes of palladium and silver nanoparticles synthesized by the radiation-chemical method in micellar solutions of a surfactant (AOT) at different degrees of hydration ω0 = [H2O]/[AOT]. Silver and palladium nanoparticle sizes are in the ranges of 1.5–5.3 and 1.5–3 nm. The results obtained have been compared with the data of atomic force microscopy. It has been shown that the sizes of nanoparticles synthesized in micellar solutions must be corrected with allowance for the contribution of micelle shell thickness.

1,1-Dimethylhydrazine is a toxic component of a widely used rocket fuel. Chromatographic determination of polar 1,1-dimethylhydrazine in aqueous solutions is carried out as the analysis of its non-polar derivatives usually. The 1,1-dimethylthiosemicarbazides were synthesized as the reaction products of 1,1-dimethylhydrazine and ethyl-, allyl-, and phenyl- isothiocyanates. The purpose of this work was to investigate the possibility of the chromatographic separation of the reagents and the reaction products as well as to create the grounds of the quantity analysis of 1,1-dimethylhydrazine in aqueous solutions as its S,N-derivatives. Theoretical and experimental studies of the chromatographic behavior and adsorption characteristics of different thiosemicarbazides were carried out. It was shown that allyl- and ethyl-isothiocyanates, and corresponding derivatives of 1,1-dimethylhydrazine (1,1-dimethylthiosemicarbazides) can be separated effectively by gas chromatography–mass spectrometry technique using a capillary column with polydimetylsiloxane. Mass-spectra of ethylandallyl- thiosemicarbazides were obtained and investigated. Retention characteristics of isothiocyanates and thiosemicarbazides were calculated by two different methods. The molecular statistical calculations of their adsorption characteristics on the ideal carbon surface were performed as well as their retention characteristics were calculated using the increments of the functional groups of isothiocyanates and thiosemicarbazides. The simplified models of molecules with rigid and non-rigid bond lengths were used. The different approaches to taking into account of internal rotation of the molecule were used A satisfactory correlation has been obtained between the experimental and theoretically calculated retention characteristics of thiosemicarbazides and isothiocyanates on the non-polar stationary phase. The derivative of 1,1-dimethylhydrazine with phenylisothiocyanate is too thermallyunstable to be analyzed by gas chromatography. The recommendations on gas chromatographic analysis of such mixtures are given.

The problem of determining the most toxic halogen- and sulfur-containing organic compounds at the trace level in different media by rapid screening based on the high-temperature oxidative conversion of a sample in combination with ion chromatography being solved at the Department of Analytical Chemistry of Moscow State University is considered. This approach ensures the rapid control of the total content of organic compounds containing F, Cl, Br, and S atoms in a molecule, regardless of the availability of data on their presence in the sample.

A protein–peptide complex isolated from cattle ovarian tissues was studied. It was shown that it contains polypeptides with molecular weights from 800 to 6000 Da and a protein of the mammalian albumin family with a molecular weight of 66 690 Da containing the 16-member N-terminal amino acid sequence DTHKSEIAHRFKDLGE. The use of a model of the roller organotypic cultivation of rat ovaries demonstrated that the effect of this protein–peptide complex at low total protein concentrations of 10–8–10–15 mg/mL contributes to increases in the viability and maturation of secondary follicles in rat ovarian tissues in vitro.

Предложено модифицированное уравнение линейного разложения газохроматографических параметров для описания способности метакрилатных полимеров к различным типам межмолекуляр- ных взаимодействий (ММВ). Уравнение позволяет не только оценивать полярность полимеров, но и определять вклад каждого типа ММВ в удерживание молекул.

The paper addresses the effect of a new fatty acid elongase 6 (ELOVL6) inhibitor on the migration of breast cancer cells (estrogen receptor positive MCF7 cells and estrogen receptor negative MDA-MB-231 cells) and expression of genes associated with the epithelial-mesenchymal transition, the first stage of tumor metastasis. It was shown that inhibition of the synthesis of C18 fatty acids does not change the migration activity or expression of transcription factors regulating the epithelial-mesenchymal transition. At the same time, the inhibition of ELOVL6 resulted in overexpression of genes associated with breast cancer development and metastasis in vivo (EGFR, CASP4 and VEGFA).

The metal-carbon sorbents based on ultradispersed porous shungite modified with nanoparticles ofsilver in the reverse-micellar solutions were synthesized. Physical-chemical properties of the metal-organicmaterials were investigated by energy-dispersive X-ray analysis (EDX) and surface-assisted massspectrometry with laser desorption / ionization method (SALDI-MS). It was observed that nanoparticles of silver are distributed on the shungite surface uniformly and retain strongly at the sorbent with 75% shungite carbon. The process of silver ionization on the shungite surface is hampered. Low desorption of silver from the modified surface of ultradispersed porous shungite, as well as the thermal stability of shungite near 500оС makes it possible the avoidance of the metal loss during filtration and regeneration. The adsorption of phenol on the shungite modified with nanoparticles of silver was studied by SALDI-MS. No clusters containing molecules of phenol and silver were found on the metal-carbon sorbent after adsorption of phenol. There is no interaction of phenol and silver nanoparticles on the shungite surface. The dispersity and hydrophilicity of the shungite powder in water were increased due to the modification of its surface with silver nanoparticles. It was proposed that silver modified shungite can be stable and effective sorbent for purifying of water and it is resistant to the regeneration processes. Thus metal-carbon sorbent based on ultradispersed porous shungite modified with silver can serve as a basis for producing of the new class of hybrid organic-inorganic materials for nanotechnology. A complex of hydrophilic, hydrophobic, acidic, basic, and bactericidal properties, appearing in the composition of shungite modified with silver nanoparticles, makes possible its application as sorbent, filler, catalyst and component of composite materials for medical application.

The retention of glycine-based peptides on a Hypercarb carbon adsorbent is studied by reversed-phase HPLC. In the reaction mixture obtained in the synthesis of polyglycines, ions corresponding to both linear and cyclic peptides are detected by electrospray ionization mass spectrometry. Characteristics of the retention of the components are determined on varying the composition of the mobile phase in the isocratic mode. It is shown that some of the detected ions are fragmented ions of linear polyglycines rather than protonated individual cyclic peptides, which complicated identification. The presence of five linear polyglycines as well as cyclodiglycine in the test mixture is confirmed.

The problem of passivation of rocket-carriers upper stages propellant tanks containing residual propellant components is under consideration. Based on the introduction of boundary conditions in the form of the heat equation with boundary conditions corresponding to the uniform distribution of the liquid residues of the rocket propellant components (RPC), a multilevel mathematical model of convective heat transfer is developed. The effect of dispersed material in the form of aluminum nanopowders on the evaporation of liquid kerosene residues is studied. The results of kerosene residues evaporation processes for a heat carrier based on combustion products of asymmetric dimethylhydrazine and nitrogen tetroxide are considered, taking into account the additives of the dispersed material.

The interaction between asymmetric dimethylhydrazine and thiocontaining mineral schungite-III has been studied. Chromatography–mass spectrometry has been used to identify alkyl polysulfides as the products of desorption of asymmetric dimethylhydrazine from schungite surface. The interaction of asymmetric dimethylhydrazine with crystalline sulfur has been investigated in a model system. Dimethyl polysulfides, CH3SnCH3; (dimethylamino)methyl polysulfides, (CH3)2NSnCH3; and bis(dimethylamino) polysulfides, (CH3)2NSnN(CH3)2, with 2 ≤ n ≤ 4 have been detected. Gas-chromatographic retention indices have been determined for the products of the interaction of asymmetric dimethylhydrazine with sulfur and the schungite material.

Chromatography–mass spectrometry and thermodesorption mass spectrometry have been employed to study mineral schungite-III, in which various thiocompounds have been detected and identified. The influence of these compounds on the adsorption activity of schungite with respect to iodine has been investigated. It has been shown that sulfur present in schungite has no effect on the results of determining its adsorption activity and does not interact with iodine; however, it can interact with amino compounds to yield sulfides. Activation energies Ea have been experimentally determined for sulfur, iodine, and dimethyl disulfide desorption from the surfaces of schungite and a model sorbent, graphitized thermal carbon black. The Ea values of these compounds have appeared to be several times lower than the heats of their adsorption on carbon black calculated by the molecular-statistical method.

Examples of cluster formation from inorganic and organic compounds upon surface-assisted laser desorption/ionization have been considered. It has been shown that the cluster formation is especially efficient upon ionization of silver halides. The addition of silver salts to salts of other metals, in particular, lead and nickel salts and sodium stannate, leads to the formation of mixed clusters. The peak intensities of the ions of such clusters are higher than those of the clusters of initial salts, thereby indicating a higher efficiency of their formation. Nonpolar amino acids and short-chain peptides predominantly form adducts with alkali-metal ions.

The influence of composition of shungite material on its sorption properties in respect to biologically active compounds with different functionality is studied using mass spectrometry methods. It is shown that the concentration of the organic component in shungite weakly affects the composition of the ionized products of laser desorption of phenol, benzoic acids, and amines from its surface.

MALDI-TOF was used to study molybdenum dioxide (MoO2) containing a nanosized fraction. The composition of cationic clusters of nonstoichiometric lower molybdenum oxides in the gas phase was determined, and the thermodynamic stabilities and configurations of isomers were calculated for selected symmetric molecular structures and for cations MoSO 8 + and Mo5O 9 + . Molecular orbital analysis was performed for two trigonal-bipyramidal clusters Mo5O8 and Mo5O9. Changes in molybdenum–molybdenum interatomic distances in going from MoO 8 + and Mo5O 9 + cations to neutral clusters are discussed.