Chromatography and mass spectrometry have been used to study the effect of shungite composition on its reaction with 1,1-dimethylhydrazine and its oxidative transformation products. Compounds contained in aqueous solutions of 1,1-dimethylhydrazine before and after its contact with shungite, as well as on the surface of shungite with different ratios of organic and inorganic components, have been analyzed qualitatively and quantitatively depending on the contact time. It has been found that the composition of shungite affects the products of its reaction with 1,1-dimethylhydrazine.

The hydrophobicity of antibacterial peptides of Galleria mellonella calculated using the HyperChem and SSRCalc algorithms of the additive chromatographic separation model has been compared with experimental data on the separation of these peptides by reversed-phase high-performance liquid chromatography on SiO2-C18. It has been found that there are some groups of peptides of different structures and functionalities, the chromatographic behavior of which can be adequately described on the basis of a preliminary assessment of their hydrophobicity. Within these groups, retention values of the peptides can be predicted for their identification.

Experimental results from determining parameters of the chromatographic retention of antimicrobial peptides of the immunized hemolymph of Galleria mellonella under conditions of gradient reversed-phase high-performance liquid chromatography (RP HPLC) are compared to ones from theoretical calculations by analyzing their parameters of hydrophobicity (SSRCalc model) or effective energies of the adsorption of amino acid residues to predict the retention of peptides and solvent components (BioLCCC model). It is found that none of the considered models fully describes the separation of antimicrobial peptides differing in structure and composition, but the SSRCalc algorithm allows acceptable reliability to be achieved in predicting the retention of 1–7 kDa peptides. The greatest errors of approximation are found for peptides with disulfide bridges and unprotected terminal polar functional groups.

Reversed-phase HPLC (RP-HPLC) is used to study conditions for the separation of mixtures of antimicrobial peptides of the Galleria mellonella hemolymph. Target peptides are quantitatively isolated and identified via MALDI mass spectrometry. The thermodynamic and kinetic characteristics of the sorption of induced peptides on octadecyl silica gel and porous graphitized carbon are determined. Correlations are obtained for the calculated and experimental retention of peptides and their primary structure and retention. The optimum conditions for separating mixtures of antimicrobial peptides of immunized hemolymph are determined using a Zorbax EclipseXDB-C18 column under conditions of gradient elution.

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.

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 .

Possibility of combined application of Thermo-Desorption Mass Spectrometry, Matrix-Assisted Laser Desorp-tion/Ionization (MALDI), and Surface-Assisted Laser Desorption/Ionization (SALDI) methods to examination of construction materials surface has been demonstrated, AMg-6 alloy being taken as an example. Organic and inorganic impurities on the alloy surface are identified. The depth of penetration of organic and inorganic compounds into alloy undersurface layers is assessed. Activation energies of processes of desorption and chemisorptions have been deter-mined. Three-dimensional distribution diagrams for compounds-markers over the AMg-6 alloy surface are presented.

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.

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.

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 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.

Проведены теоретические и экспериментальные исследования возможности хроматографического разделения смеси реагентов и продуктов взаимодействия 1,1-диметилгидразина с изотиоцианатами. Методом газовой хроматографии с масс-спектрометрической детекцией эффективно разделенысмеси этил- и аллилтиосемикарбазидов с реагентами на полидиметилсилоксановой неподвижной фазе. Получена удовлетворительная корреляция между экспериментальными и теоретически рассчитанными характеристиками удерживания тиосемикарбазидов и изотиоцианатов на неполярной неподвижной фазе.

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.