Vol 25, No 1 (2025)
Chemistry
Quantitative chemical analysis of water in the application of membrane fi ltration
Abstract
Water pollution poses a danger to human health and, as a result, there is a need to identify ways to clean it. In this study, a quantitative chemical analysis of water taken from the well and after its passage through membrane purifi cation (reverse osmosis method) was carried out in the period from 2019 to 2023. The research area is Moscow, Moskovsky settlement. The following physico-chemical characteristics were determined: odor, color, turbidity, pH, total hardness, permanganate oxidizability, mass concentration of ammonium ions, total iron (Fe2+ and Fe3+), nitrates, nitrites, manganese, fl uorides, chlorides, dry residue, sulfates, anionic surfactants, petroleum products. The results obtained have shown the eff ectiveness of the use of membrane water purifi cation. The color has decreased. The turbidity, which exceeded the normative indicators (7.7), became within the normal range – 2.1. The values of the dry residue and premanganate oxidizability did not change signifi cantly, their values were within acceptable values in the initial water samples. The high iron content exceeding the MPC decreased to acceptable values (from 0.882 to 0.188 mg/dm3 on average during the study period at a MPC of 0.3 mg/dm3 ). The method allows to reduce the increased content of manganese (from 0.19 to 0.03 mg/dm3 at MPC 0.1 mg/dm3 ) and petroleum products (from 0.16 to 0.06 mg/dm3 at MPC 0.1 mg/dm3 ), as well as ions NH4+, NO3-, NO2-, F- , Cl- , SO4 2- and surfactants.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):4-13
4-13
Synthesis of new hybrid molecules based on 7-hydroxy-2,2,4-trimethylhydroquinoline derivatives
Abstract
Among the fused azaheterocycles, quinolines have long attracted the attention of chemists. First of all, this is due to their wide range of practically useful properties. Quinolines and their derivatives exhibit a wide range of biological activities, including antimalarial, anticancer, antiviral, antifungal and anti-infl ammatory activities. These compounds are also used as fl uorescent probes, luminescent labels, and in dye production. In the course of this work, a series of pyridocoumarin systems have been obtained, which have been tested as inhibitors of blood clotting factors Xa and XIa. The method for the synthesis of the proposed compounds involves the condensation of 7-hydroxy-2,2,4-trimethyl-1,2- dihydroquinolines and 7-hydroxy-2,2,4-trimethyl-1,2,3,4-tetrahydroquinolines with malononitrile and aryl(hetaryl)aldehydes. It has been found that as a result of this interaction, new 4H-pyrano[3,2-g]quinoline-3-carbonitriles are formed. In addition, new derivatives of 7-hydroxy-2,2,4- trimethyl-1,2,3,4-tetrahydroquinoline containing an aryl fragment in the 4-position have been obtained, which have been also used as starting compounds for the annelation reaction of the pyran ring. The pyridocoumarin systems obtained in the study have showed promising inhibitory activity against these coagulation factors, making them promising candidates for further study as potential anticoagulant drugs.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):14-22
14-22
Oxidative degradation of tetracyclines
Abstract
Environmental pollution is one of the most pressing problems facing humanity. The constant search for its solution is an important aspect of modern chemistry. The work studied the oxidative degradation of two antibiotics of the same pharmaceutical group, with a similar structure but diff erent properties. The purpose of this work was to study the oxidation process of the active substances of two antibiotics: tetracycline and doxycycline by various oxidative and combined systems: the Fenton system, the Ruff system, their combined action, their action in the presence of EDTA, as well as under the action of UV irradiation. The conducted studies have shown that under conditions of room temperature and normal atmospheric pressure, hydrogen peroxide in combination with iron (II) and (III) ions is able to oxidize the active components of tetracycline and doxycycline. The optimal conditions for the oxidation of the tetracycline group of antibiotics have been determined: the concentration of the substrate, hydrogen peroxide, iron (II) ions, iron (III) ions, and the pH of the reaction. It has been shown that the combined presence of iron (II) ions and iron (III) ions in the system reduces the consumption of hydrogen peroxide during the oxidation of active substances of tetracyclines. It has been shown that the replacement of hydrated iron ions with iron complexes with EDTA has a slight eff ect on the oxidation effi ciency of tetracycline and doxycycline. It has been revealed that iron (III) complexes with EDTA are more eff ective in the destructive process of tetracycline. It has been established that the active substance of tetracycline preparations undergoes destruction under the action of UV irradiation. It is shown that photodestruction reactions of active substances of tetracyclines are reactions of the fi rst order. The rate constants of these processes are determined. It has been revealed that the destruction of doxycycline proceeds most fully under the action of the Raff system, as well as under the action of UV irradiation in the presence of hydrogen peroxide. It is shown that the studied oxidative systems are eff ective for the destruction and inactivation of pharmaceutical pollutants belonging to the tetracycline group.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):23-33
23-33
Non-destructive control of tablet forms of cefuroxime by near-infrared spectroscopy and digital colorometry methods
Abstract
Non-destructive control of cefuroxime in tablet medicines without opening the blister pack by measuring the intensity of diff use refl ectance of infrared radiation has been proposed. Near-infrared Fourier transform spectroscopy and digital color spectroscopy using a smartphone and a 3D-printed device have been applied. The data set has been processed by principal component methods, hierarchical cluster analysis and partial least squares regression. The application of chemometric algorithms to determine the concentration of the active ingredient cefuroxime in the drug Zinnat has been considered. The methods of infrared spectroscopy and colorometry have showed comparable results in terms of accuracy in determining the concentration of active ingredient in tablets without opening the blister pack.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):34-41
34-41
Modified planar sensors for the separate detection of certain cephalosporin antibiotics
Abstract
Modifi ed screen-printed potentiometric sensors sensitive to cephalosporin antibiotics – cefuroxime (Cefur), cefotaxime (Ceftx), cefazolin (Cef) have been developed. Tetradecylammonium associates with complex compounds silver (I) – cefuroxime (cefotaxime) have been used as electroactive components. The role of magnetic nanoparticles Fe3O4 and cetylpyridinium chloride in improving the electroanalytical properties of sensors in solutions of the studied antibiotics is shown. Optimal ratios of modifi ers in carbon-containing inks (Fe3O4 : CPCh = 1 : 2.5) have been found. The main electroanalytical characteristics of the modifi ed sensors are determined. The introduction of a binary mixture of magnetic nanoparticles and cetylpyridinium chloride into carbon-containing inks leads to an improvement in the electroanalytical properties of planar sensors sensitive to cefuroxime, cefotaxime, cefazolin: at the same time, the detection limit of 1 · 10-6 (1 · 10-7 M) decreases, angular coeffi cients (55 ± 3 mV/pC) and linearity intervals of electrode functions (1 · 10-6 – 1 · 10-2 M), the response time is reduced – 26–30 seconds. The adsorption of surfactants at the interface ensures the stability of the suspension of nanoparticles and allows the concentration of analyte molecules. The possibility of separate determination of cephalosporin antibiotics in two- and three-component mixtures by projection methods of multidimensional data processing PLS-1 and PLS-2 is shown. The standard errors of calibration and prediction are estimated, on the basis of which the optimal number of latent variables for these methods is selected. It is established that all the studied models give high values of correlation coeffi cients and tangents of the slope of the “measured-predicted” dependencies close to one, which makes it possible to recommend these methods for practical use.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):42-55
42-55
Improving the effi ciency of using sands as artifi cial geochemical barriers
Abstract
The interaction of sands as artifi cial geochemical barriers with nickel chloride solutions simulating technological effl uents is investigated. The eff ect of pre-acid treatment of sands on their ability to absorb nickel (II) ions is considered experimentally. In experiments, sands with diff erent quartz contents have been studied, in which the only impurity element was aluminum oxide in an amount from 1 to 10% (wt.). Pretreatment of sands with 0.1 M hydrochloric acid solution has been carried out for 0.5 hours by stirring a water-sand suspension on a magnetic stirrer. Traditional methods of colloidal chemical research have been used. Under static conditions, a fl ask with a sand suspension (3 g) and a solution has been placed in a special shaker, under dynamic conditions, a solution has been passed through a layer of sand (3 g) in a column. The nickel (II) content in the solutions has been determined by photometric method with dimethylglyoxime. According to the results of adsorption studies, an increase in the maximum adsorption values from 15–20 to 50–56% has been achieved, depending on the type of sand and the quartz content in it. When fi ltering solutions through a layer of sand, the degree of retention of nickel (II) ions on the activated surface of the grains increases. At a fi ltration rate of 1×10-3 dm3/min and the same fi lling height (2.7 ± 0.1 cm), the effi ciency of removing nickel ions from the solution increases. At the same time, an increase in effi ciency by 1–1.5% is typical for sands with high natural indicators of 95–98%. On sands, the natural capacity of which initially does not exceed 65–70%, the increase in effi ciency is more signifi cant and amounts to 5% or more. In general, the increase in effi ciency is proportional to the quartz content, i.e., the treatment of sand grains with hydrochloric acid activates mainly those areas of the surface on which silicon bonds are localized, i.e. siloxane and silanol groupings, which act as adsorption centers.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):56-65
56-65
Biology
Addition to the summary of cryptogam vascular and gymnosperms plants: “Flora of the Lower Volga Region” (based on materials of the herbarium of SSU (SARAT))
Abstract
The article presents the results of a comparative analysis of the distribution of cryptogam vascular and gymnosperms plants in the Lower Volga region based on materials from the herbarium of the Saratov State University (SARAT). Plants of the devisions Lycopodiophyta, Equisetophyta, Polypodiophyta and Pinophyta are among the ancient representatives of the fl ora of the globe. The rarity and increased vulnerability of species of these devisions is caused by both natural and anthropogenic reasons. For the entire existence of the herbarium of Saratov State University (SARAT) collected a signifi cant amount of valuable material on cryptogam vascular and gymnosperms plants, which is currently being processed and systematized. To clarify the distribution of species, the data from the report «Flora of the Lower Volga Region» and the herbarium of the SSU (SARAT) were analyzed, since when writing the fi rst volume, the herbarium data were only partially used. The herbarium of the SSU (SARAT) registered 33 species of higher spore-bearing vascular plants: Lycopodiophyta – four, Equisetophyta – six, Polypodiophyta – 19 and Pinophyta – four out of 41 species indicated in the literature for the Lower Volga region. The fund currently contains 1539 herbarium sheets related to the studied devisions the collections of which were carried out from 1902 to 2017. The most numerous is the Polypodiophyta devision, followed in descending order by the Equisetophyta, Pinophyta and Lycopodiophyta. The largest number of specimens were herbalized in the Saratov region, the Astrakhan region is in second place, and the Volgograd region is in third place. As a result of a comparative analysis for 23 species, the understanding of their distribution in the studied area has been expanded.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):66-75
66-75
Ex vivo model of using the method of optical skin clearing during antimicrobial photodynamic action
Abstract
This study evaluated the effi cacy of transcutaneous photodynamic therapy using blue (428 nm) LED irradiation on Staphylococcus aureus 11 in combination with a water-soluble cationic pyridyl porphyrin and optical clearing agents (OCA) in an ex vivo model. Results showed that OCA signifi cantly enhanced photodynamic inactivation with a 61% reduction in bacterial cell counts after 15 minutes of light exposure, comparable to direct irradiation. Optical parameter analysis revealed a decrease in scattering and absorption coeffi cients and an increase in light penetration depth (up to 121,6%) in OCA-treated skin samples. The results confi rm that optical clearing improves the effi cacy of antimicrobial photodynamic action by enhancing light penetration into deeper tissue layers, reducing the need for high laser intensities, and minimizing superfi cial tissue damage. This approach holds promise for the treatment of skin, mucosal and soft tissue infections in humans and animals, off ering valuable insights into light-tissue interactions and optimizing photodynamic therapy while reducing the risks associated with the use of LEDs and lasers.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):76-88
76-88
Ecology
Mycetophilous beetles (Coleoptera) of the Saratov Oblast: The results of fi ve years of research
Abstract
During fi ve years of research (2017–2020 and 2022), 257 fruiting bodies of 34 species of basidiomycetes from the orders Agaricales and Polyporales, Hymenochaetales, Boletaceae, Russulales and Gloeophyllales were collected in diff erent areas of the Saratov region. 108 species of Coleoptera from 24 families were identifi ed that are directly and/or indirectly associated with the fruiting bodies of fungi. The highest species diversity was noted in the families Staphylinidae – 37 species, Tenebrionidae – 11, Ciidae – 10, Erotylidae and Mycetophagidae – 6 species each. In terms of frequency of occurrence, Diaperis boleti predominates, found on 16 (out of 34) basidiomycetes, Dacne bipustulata (13), Mycetophagus quadripustulatus (12) and Gyrophaena joyi (11). The same mycetobiont species dominate in the collections in terms of abundance of Diaperis boleti (30.6%), Dacne bipustulata (17.7%), Mycetophagus quadripustulatus (10.2%) and Gyrophaena joyi (7.9%). For four fungal species (with perennial and annual cycles of fruiting body development), the succession of mycetophilous Coleoptera could be traced. The trophic groups of Coleoptera on fungi are mainly represented by mycetophages in the broad sense (72.5%), predators (14.1%), sapronecrophages and detritivores (13.4%).
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):89-99
89-99
Ecological and hygienic studies of the aerial part of wormwood of the bitter synanthropic flora of Central Russia
Abstract
Central Russia is traditionally the most important area of crop production and agriculture. The purpose of this study was the ecological and hygienic study of the accumulation of heavy metals and arsenic, as well as biologically active substances in the aboveground part of bitter wormwood (Artemisia absinthium L.), harvested in urbocenoses of Central Russia. Under the conditions of the experiment, more than 50 samples of the aboveground part of bitter wormwood prepared in the territories of the Voronezh region, which are diff erent in terms of anthropogenic impact, from a typical region of central Russia, were analyzed for the content of heavy metals and arsenic, as well as fl avonoids, extractive substances and essential oils. The presence of physiological barriers that prevent the accumulation of an excess of a number of toxic elements (lead, cadmium, mercury, arsenic, cobalt, nickel, chromium) in the plant was revealed. The aerial part of the wormwood is bitter with signifi cant accumulated quantities of copper and zinc. The peculiarities of accumulation of heavy metals should be taken into account when planning places for harvesting bitter wormwood and assessing the quality of raw materials. It was revealed that the accumulation of bitter flavonoids and extractive substances extracted with 70% ethyl alcohol in the aerial part of wormwood is slightly infl uenced by the toxic elements determined; for all heavy metals and arsenic, a negative eff ect on the content of essential oils was noted.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):100-113
100-113
Diversity and development of cyanobacteria in the Volga-Caspian sea
Abstract
Studying the development of such an important group as cyanobacteria is an integral part of environmental monitoring of the Volga-Caspian region. Based on long-term data, a comparative description of the current state of the group of cyanobacteria of the Volga-Caspian region is indicated. The degree of similarity of marine and river species of the group of cyanobacteria for sections of the Volga River, Northern and Middle Caspian Sea was determined. Calculation of the percentage contribution of cyanobacteria to the total composition of phytoplankton in the studied water areas made it possible to estimate their importance. The dominant species among the studied group of microalgae and its quantitative characteristics in the considered water areas were identifi ed. During periods of growth of cyanobacterial biomass, a large proportion of it consists of large colonies of cells (species of the genus Microcystis, Gomphosphaeria), which become available in the form of detritus as food for organisms of most links in the trophic network after death, which has a positive eff ect on the development of these organisms. Changes in the indicators of the group of cyanobacteria over a number of years and relative to long-term data indicate their quantitative decline, however, the species diversity of the group remains at a fairly high level. The purpose of the work is to establish the qualitative diversity of cyanobacteria in the river and sea and to clarify their role in the phytoplankton of the Northern and Middle Caspian Sea and the lower part of the Volga River.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):114-117
114-117
The substrate spectrum of native hydrocarbon-oxidizing bacteria isolated from soils with diff erent levels of anthropogenic impact
Abstract
The substrate spectrum of hydrocarbon-oxidizing bacteria isolated from the soils of the Saratov region was studied: the soils of Balakovo (chronic anthropogenic pollution) and agricultural soils of Novokrivovka village (single hydrocarbon pollution). It was found that the microorganisms isolated from the urban soils of Balakovo, being under constant anthropogenic infl uence, had a wider substrate spectrum. It was revealed that 4 microorganisms isolated from the urban soils of Balakovo: Acinetobacter lwoffi i R44, Bacillus circulans E75, B. horikoshii P22, Ochrobactrum gallinifaecis I59, and also Paenibacillus polymyxa S31, isolated from the soil of Novokrivovka village, were capable of decomposing the largest amount of hydrocarbon substrates, including crude oil and individual hydrocarbons. 100% of bacterial strains isolated from the soils of Novokrivovka village and 75% of microorganisms isolated from the soils of Balakovo used crude oil as the only carbon source. The number of bacteria capable of using aromatic hydrocarbons for growth was 2–3 times higher among isolates from the soils of Balakovo. Native hydrocarbon-oxidizing bacteria with a wide substrate spectrum can be used to design a biological product aimed at carrying out restoration activities of contaminated soil ecosystems.
Izvestiya of Saratov University. New series. Series: Chemistry. Biology. Ecology. 2025;25(1):118-123
118-123