New derivatives of arginine and nicotinic acid with essential elements zinc and magnesium were obtained and characterized. A method for producing arginine nicotinate with a purity of 99.80 % and a yield of 88.00 % has been developed, and its IR and NMR spectroscopic characteristics have been obtained. A method for obtaining zinc and magnesium derivatives of arginine nicotinate has been developed. Based on NMR and IR spectra, the structure of the obtained compounds was confirmed. The composition of the obtained samples was determined using elemental analysis and complexometric titration. The content of the target component for zinc arginine nicotinate was 92.64 ± 0.32 %, and for magnesium arginine nicotinate – 85.12 ± 0.81 %.

The surface activity of certain bicyclic surfactants from the camphane group of terpene series in aqueous and saline solutions was studied. It has been shown that bicyclic compounds with a rigid hydrocarbon framework exhibit high surface activity, especially in electrolyte solutions. This fact makes it possible to use them in the flotation of soluble salts. The main characteristics of the adsorption layer were determined: surface activity, saturation concentration of the adsorption layer, maximum adsorption, and the area occupied by a molecule in the adsorption layer. It is shown that the structure of the hydrophobic radical has a significant effect on the structure of the surface layer, and the presence of an aliphatic chain in the hydrocarbon skeleton contributes to an increase in the surface activity of the surfactant.

Twelve samples of commercial engine oils of the same viscosity class 10w-40 were analyzed using gas chromatography with flame ionization and mass spectrometric detection (hereinafter referred to as GC/FID and GC/MSD, respectively). It was shown that the identification of engine oils by GC-FID, as well as GC/MSD with data collection in the total ion current mode, does not practically allow us to detect differences between the studied motor oils due to very minor differences in the recorded chromatograms of the corresponding samples. It is shown that the use of GC/MSD with the registration of chromatograms in the selected ion mode, characteristic of unique petroleum biomarkers, makes it possible to identify differences in the component composition of the considered oils. The obtained experimental data demonstrate the possibility of using a semi-quantitative assessment of the content of petroleum biomarkers for the identification of oils during forensic examination of petroleum products and fuels and lubricants (hereinafter referred to as PP and FL). Based on the content of biomarkers in commercial engine oils, it is also possible to detect adulteration of highly refined semi-synthetic or synthetic oils by substituting or mixing mineral oils made without proper processing.

The reaction of hydroxybenzaldehydes with picolinic (2-pyridinecarboxylic) acid in the presence of DCC in dichloromethane afforded the corresponding esters in 77−88 % yield. By subsequent condensation of aldehydoesters with 4-aminoantipyrine in boiling methanol were synthesized their (E)-4-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1h-pyrazole4-il)imine in 65−75 % yield, but azomethines based on 2and 3-formylphenyl picolinates couldn’t be obtained due to alcoholysis of the ester groups. Quantum-chemical modeling of the electronic structure of the synthesized compounds using ab initio method with the HF/6-31G level of theory was performed for preliminary assessment of their potential antibacterial and antiviral properties.

Detection of Listeria monocytogenes (LM) in foods is topical due to known cases of listeriosis epidemics. Immunochemical methods including ELISA are widely used for LM detection. Traditionally, commercial ELISA kits for LM detection in foods are based on sandwich technique, detect antigens of bacterial cell membrane, have analytical sensitivity ~ 10⁵ CFU/mL, and the analyzed biomaterial is cells + medium. We elaborated competitive ELISA test for LM detection in foods with analytical sensitivity 1  10⁴ CFU/mL. The test system differs from known analogues (commercial and described in research studies) by two design features: the membrane-free fraction of LM cells (cytosol) is immobilized on the solid |phase; the analyzed biomaterial is the medium in which the bacteria were grown. Adaptation of this test system to the ELISA detection of LM in milk revealed a pronounced matrix effect that could not be eliminated by conventional methods. We addressed this issue by adding milk to the calibration samples immediately before performing the ELISA, maintaining an analytical sensitivity of 1 · 10⁴ CFU/mL.

The paper studies the regularities of formation and antioxidant activity of interpolyelectrolyte complexes (IPECs) based on chitosan-Ag and pectin-Ag nanocomposites, as well as pectin and oxidized pectin. The technique for fabricating porous IPEC-based materials has been developed, and parameters allowing to regulate their structure and physicochemical properties have been determined. IPEC-based matrices are characterized by high porosity (> 95 %) and a density ranging from 15.5 to 28.8 mg/cm3. It has been established that the qualitative composition of the complexes (the type of polyanion in IPECs) has the main effect on the degree of degradation of the porous materials under the studied time period (up to 7 days). Samples based on oxidized pectin demonstrated the best stability in a model medium (Dulbecco’s phosphate-buffered saline), retaining their shape and integrity, while their average mass loss was 23.4 ± 10.0 %. The obtained porous materials based on IPECs may be of practical interest for application in wound dressings as an active layer carrying antibacterial and antioxidant functions.

The possibility of obtaining complex organomineral NPK-fertilizers based on nodular phosphorites of Karakalpakstan and washed burned concentrate (WBC-26) from Kyzylkum phosphorites by treating them with a product of oxidized and ammoniated brown coal from the Angren deposit with subsequent addition of potassium sulfate, ammophos, urea and ammonium nitrate powders to the mixture, has been shown. The phosphate mineral of the Khodzhakul raw material consists of kurskite and francolite in equal quantities, and the Porlytau raw material consists of kurskite only. WBC-26 is of granular type, the main mineral of which is francolite. It has been established that among the developed complex fertilizers, the most concentrated in terms of the amount of nutrients is the product obtained in the presence of urea. In products made from nodule phosphate flour of Karakalpakstan, the relatively high relative content of the digestible form of phosphorus indicates their high reactivity. When introducing the proposed new types of complex fertilizers based on local raw materials, the soil structure noticeably improves, while expensive mineral fertilizers are saved by 30–35 %, and irrigation water – by 10–12 %. Additionally, cotton yield increases by 2–4 %.

The effect of granulometric composition of silica sand from the Lenindar deposit (Republic of Belarus) on glass-formation processes during the Na₂O–MgO–CaO–SiO₂ glass system synthesis was studied. The data were obtained on influence of different fractions of silica sand on the sequence of processes occurring during the batch heat treatment and the dissolution rate of silica grains which determines the duration of glass formation. Scanning electron microscopy was used to study the influence of temperature and time modes of the heat treatment on the grain sizes of residual silica and the degree of melt homogeneity at the glass formation stage. Based on the data of electron probe microanalysis, the rate and time of dissolution of silica grains of different fractional composition in the glass-forming melt were calculated. The results of glass formation processes monitoring and the quality of flat glass revealed that the usage of the expanded silica sand fractional composition is possible. This composition can include the grains of 0.8–1.25 mm in size when the glass melting proceeds in high-performance furnaces. That will allow more rational use of limited resources of this raw material.