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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.

Products of interaction between alkylhydrazines and ethyl-, allyl-, and phenylisothiocyanates are studied using mass spectrometry in the modes of electron impact ionization and matrix-assisted laser desorption/ionization in combination with gas and liquid chromatography. Conditions for the chromatographic separation of reaction mixtures and mass spectrometric identification of target compounds in real-time and delayed modes are optimized. The physicochemical characteristics of the sorption of thiosemicarbazides are determined. The decomposition and fragmentation of their metastable protonated molecules are studied. Schemes are proposed for the formation of fragmented and characteristic thiosemicarbazide ions in different modes of ionization.

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.

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.

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.

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.

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 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.

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.

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 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 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.

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.

Chromatography–mass spectrometry and MALDI mass spectrometry have been used to study the interaction of 1,1-dimethylhydrazine and products of its oxidation with the surface of mineral schungite in aqueous solutions. A comparative analysis has been performed for organic compounds contained in initial and equilibrium 1,1-dimethylhydrazine solutions brought in contact with schungite, as well as compounds desorbed from the modified surfaces of the mineral and its inorganic components. The analysis has revealed the efficiency of schungite as a low-cost and environmentally friendly sorbent capable of catalyzing the profound oxidation of 1,1-dimethylhydrazine and products of its transformation to nontoxic low-molecularmass substances. Environmentally safe methods have been proposed for the regeneration of used schungite.

The influence of thermo- and mechanochemical modification of mineral shungite-III (Karelia, Russia) on its chemical composition and physicochemical properties has been studied. A method has been proposed for the mechanochemical modification of shungite, which yields a finely dispersed sorbent with a specific surface area of 70.6 m2/g, a total pore volume of 0.336 cm3/g, and a carbon concentration of higher than 75%. The comparative analysis of the thermolysis of the mineral and modified shungites in air has revealed a difference between the thermal stabilities of the samples. Almost all of the carbon of modified finely dispersed shungite combusts below 500°C, whereas the decomposition of mineral shungite starts above 600°C and only 60% of carbon combusts at 800°C.

Ionized products of desorption of biologically active amino compounds (1,1-dimethylhydrazine, diglycine, tyrosine, and tryptophan) from the surface of a modified mineral (shungite-III, Karelia) have been investigated by laser desorption/ionization mass spectrometry methods (MALDI and SALDI). The composition of the ionized products of laser desorption of amino acids from the surface of nanodispersed shungite is almost independent of carbon content in shungite. The comparative analysis of ionized organic compounds desorbed from the surfaces of shungite and carbon black has led to the suggestion that the decomposition and surface transformation of 1,1-dimethylhydrazine molecules mainly occur on the inorganic components of shungite.

A method of modification of mineral shungite (shungite-III) material was proposed that made possible a nanodispersive porous sorbent with the carbon content exceeding 75% and the pore size of 19 nm. The effect of the physicochemical modification of shungite on its composition and sorption properties was studied.

Thin-layer and high-performance liquid chromatography methods have been employed to study the interaction of diphenylpolyenes with the surfaces of SiO2 (silica gel) and SiO2-C18 in organic and aqueous media. Electronic absorption spectra of diphenylpolyenes have been measured in different solvents, and the constants of their chromatographic retention on the solid phase surface have been determined. The interaction of diphenylpolyenes with SiO2 surface in a binary organic solvent and with SiO2-C18 surface in a water-organic solvent has been shown to intensify in the series cis-1,2-diphenylethylene < trans-1,2-diphenylethylene < trans-1,4-diphenyl-1,3-butadiene < trans-1,6-diphenyl-1,3,5-hexatriene. The retention constants of diphenylpolyenes have been revealed to depend on the geometry and configuration of their molecules, the length of an olefin fragment, and the nature and polarity of an eluent.

The separation dynamics of mixtures of trans-stilbene hydroxyl derivatives (4-hydroxystilbene, 4,4′-dihydroxystilbene, α,α′-diethyl-4,4′-dihydroxystilbene (diethylstilbestrol), and 3,5,4′-trihyxrodystilbene (resveratrol)) is studied by the centrifugal (recycling) chromatography method. An algorithm of numerical modeling of the hydroxystilbene concentration front motion under conditions of a preparative thin-layer chromatography on chromatron is proposed. The correspondence of theoretical and experimental results is shown.

Methods of thermogravimetric analysis, differential scanning calorimetry, and thermal desorption mass-spectrometry are used to study the processes of thermolysis of resveratrol on the surface of graphitized thermal carbon black (GTCB). The results obtained in thermolysis of pure resveratrol and resveratrol adsorbed on GTCB from diethyl ether are compared. The regions of maximum evolution of thermolysis products are determined; their compositions are identified; an increase in thermal stability of resveratrol supported on the surface of graphitized thermal carbon black is observed.

Thermolysis of low and high molecular aliphatic carboxylated compounds in composite systems based on nanosized aluminum were studied by the thermal desorption mass spectrometry. The conditions for maximal separation of the thermolysis products and their composition were determined. The kinetic parameters of thermal desorption and thermal degradation of the modifiers were calculated. Differences in the thermal stabilities of the polymer composites based on nanosized aluminum and different modifiers (carboxylated divinyl and divinyl nitrile oligomers) were presented.

Chromatography is employed to measure the adsorption constants of hydroxybenzenes on SiO2 in a low-concentration region at varied compositions of a binary organic solvent (n-hexane-ethyl acetate). It is shown that the Henry constants vary depending on the polar-to-nonpolar component ratio in the binary solvent and the number and position of hydroxyl groups in phenol molecules. It is found that the absolute values of changes Δ(ΔG) in the free energy considerably increase as the content of ethyl acetate in the mixtures diminishes, with the ratios between the Δ(ΔG) values of ortho-, meta-, and para-isomers remaining practically unchanged. The data obtained can be used to optimize the processes of the adsorption separation of mixed polyphenols and the isolation of natural phenolic compounds on a preparative scale.

TLC, HPLC, and statistical methods are used to study the adsorption of stilbenoids from organic solvents on SiO2 in a wide range of concentrations. The dependence of adsorption of trans-stilbene hydroxy and methoxy derivatives on the nature of functional groups, their amount and position in the molecular structure, and also on the concentration and proton-acceptor properties of the polar component of the binary organic solvent is found. It is shown that experimental isotherms of stilbenoid adsorption on aerosil from the mixture of n-hexane and ethyl acetate are well approximated by the Freundlich equation. The adsorption of stilbenoids and phenols on SiO2 is compared. It is found that adsorption properties of phenols and hydroxystilbenes with a similar number of OH groups are practically similar.

Adsorption interactions of stilbene (1,2-diphenylethylene) and its hydroxy- and methoxyderivatives with nanodispersed TiO2 aerogel surface were studied by means of Fourier IR radiosity spectroscopy. Stilbene trans- and cis-isomers were shown to be weakly adsorbed on TiO2 surface forming hydrogen bonds. UV irradiation (wavelength 285–305 nm) of adsorbed compounds results in their partial destruction, yielding aldehydes, ketones, and carboxylates. The products of stilbene photolysis are strongly bound to TiO2 surface. Modification of TiO2 surface with trans-hydroxystilbenes is characterized by the formation of various hydrogen bonds and surface colored quinoid compounds. The interaction of TiO2 with trans-methoxystilbenes changes the state of surface hydroxyl groups and yields stable carboxylate compounds. UV irradiation results in the partial destruction of adsorbed stilbenoids, yielding aldehyde, ketone, and carboxylate surface compounds.

The isotherms of adsorption of trans-hydroxystilbenes (stilbenoids) and hydroxybenzenes (phenols) from n-hexane-ethyl acetate (1: 1) at nanodispersed aerogels of aluminum and titanium oxides were measured under static conditions. The adsorption isotherms can be approximated well by the Freundlich equation for the model of localized adsorption at energetically heterogeneous solids. It was found that the adsorption value of both stilbenoids and phenols is improved with an increase in the number of OH groups in their molecules, being sensitive to the chemistry of the adsorbent surface. trans-Hydroxystilbenes adsorb at TiO2 better than do the corresponding phenols. The opposite pattern was observed for Al2 O3. The adsorption of trans-hydroxystilbenes at TiO2 is irreversible and accompanied by the formation of colored surface compounds.

The adsorption isotherms of synthetic piceatannol (trans-3,5,3′,4′-tetrahydroxystilbene) from n-hexane-ethyl acetate at nanodispersed silicon, titanium, and aluminum oxides were measured under static conditions. The adsorption properties of piceatannol and other hydroxystilbenes were compared with those of polyphenols. It was found that piceatannol adsorbs at titanium oxide better than at alumina and silica and almost as well as phloroglucinol adsorbs at these oxides. The adsorption isotherms can be satisfactorily approximated by the Freundlich equation for the model of localized adsorption at energetically heterogeneous sites. The influence of the nature and concentration of the polar components of a binary organic solvent on the adsorption of piceatannol at silica gel was studied by normal-phase chromatography and UV spectroscopy. The dependences of the retention factors of piceatannol and other hydroxystilbenes on the solvent composition were described by a simple analytical equation. The optimum composition of the mobile phase for separation of piceatannol and other stilbenoids was found.

Adsorption interactions of trans-stilbene and its hydroxy and methoxy derivatives with the surface of nanodispersed SiO2 aerogel were studied by diffuse-reflection FTIR spectroscopy. Stilbenes were found to adsorb at the aerosil via hydrogen bonding to silanol OH groups. The deepest modification of these groups was produced by 3,5,4′-trihydroxystilbene (resveratrol). Although the stilbenes adsorbed reversibly, the absorption spectra of the starting and desorbed resveratrol proved to differ. UV irradiation (λ = 285–305 nm) of adsorbed hydroxystilbenes changed the composition and properties of adsorbed layers. The changes include breaking of the hydrogen bonds between the hydroxystilbene molecules and the surface, destruction of the stilbenes involving cleavage of the double bond of the ethene fragment, dimerization, oxidation, and transformation into other compounds. The intensity of heterogeneous photolysis depends on the number and composition of functional groups in trans-stilbenes.

Biocompatible calcium hydroxyapatite, Cа10(РО4)6(ОН)2 , is prepared by the alkoxide method. A functional derivative of 1,3-thiazinon (5,6-dihydro-2-methylimino-3-methyl-1,3-thiazine-4-on-6-carboxylic acid-4-chloroanilide) is synthesized, which is expected to combine anti-inflammatory and antiosteoporotic effects. Its pharmacological activity is analyzed using computer simulation. Adsorption of a 1,3-thiazinon solution in acetone on the Cа10(РО4)6(ОН)2 surface is studied with the aim of examining the possibility of preparing Cа10(РО4)6(ОН)2-based combined drugs.

The adsorption modification of nanosized aluminum particles with aliphatic carboxylic surfactants and polymers (butadiene and nitrile synthetic rubbers with carboxyl end groups) in polar and non-polar solvents was studied. Adsorption data are compared with the data on aggregation and sedimentation stabilities of aluminum dispersions. The thermal desorption mass spectrometry was used to investigate the composition and properties of modifier layers. It was shown that the use of dispersed aluminum as a filler decreases the thermal stability of compositions based on butadiene and nitrile rubbers.

Planar chiral η6-arene-Cr(CO)3 complexes represent highly valuable building blocks for the diastereo- and enantioselective synthesis. Their employment as synthons offer new and unique opportunities for the stereoselective multistep synthesis of complex natural products. The strategy of novel efficient synthesis of stilbene phytoalexins was based on arene chromium chemistry and the chemical and stereochemical effects of the metal unit on the reactivity of complexed arene ligand and stereochemical features of such compounds. Two variants for the construction of the trans-stilbene and diarylethanol framework via facilitated benzylic deprotonation of an η6-benzene-Cr(CO)3 complex and subsequent coupling with para-anisaldehyde in an aldol-type or a Wittig–Horner reaction were suggested.

Two variants of synthesis of resveratrol (3,5,4"-trans-trihydroxystilbene) from dimethyl ether and anisaldehyde were performed using the chromium η6-benzenetricarbonyl complex. The Wittig—Horner reactions or aldol condensation in four stages followed by demethylation by EtSLi were applied.

Based on the concept of an equilibrium adsorption layer in the theory of plates, an analytical solution of the problem of the linear dynamics of desorption is obtained. The regularities of the formation and motion of the output curves of desorption on adsorbent layers of small length are analyzed. The calculated and experimental data are found to be in fine agreement. A program is worked out to predict and to model the dynamics of adsorption and desorption on adsorbent layers of arbitrary length.

On the basis of the concept of equilibrium adsorption in the theory of plates, an analytical solution of the direct problem of the linear front dynamics of sorption is found. Relations of motion of C-diagrams are analyzed in the inlet section of the sorbent, and the results obtained are compared with experimental data

Two variants of synthesis of resveratrol (3,5,4"-trans-trihydroxystilbene) from dimethyl ether and anisaldehyde were performed using the chromium η6-benzenetricarbonyl complex. The Wittig—Horner reactions or aldol condensation in four stages followed by demethylation by EtSLi were applied.

New syntheses of trans-resveratrol (trans-3,5,4'-trihydroxystilbene) and pinostilbene (trans-3,4'-dihydroxy-5-methoxystilbene) via nucleophilic demethylation of trimethoxystilbene were performed, whereby trans-3,5,4'-trimethoxystilbene was obtained through facilitated benzylic deprotonation of an η6-benzene-Cr(CO)3 derivative and subsequent coupling with para-anisaldehyde in an aldol-type or Wittig–Horner reaction.

New syntheses of trans-resveratrol (trans-3,5,4'-trihydroxystilbene) and pinostilbene (trans-3,4'-dihydroxy-5-methoxystilbene) via nucleophilic demethylation of trimethoxystilbene were performed, whereby trans-3,5,4'-trimethoxystilbene was obtained through facilitated benzylic deprotonation of an η6-benzene-Cr(CO)3 derivative and subsequent coupling with para-anisaldehyde in an aldol-type or Wittig–Horner reaction.