In the presented work, a new original procedure for the interfacial synthesis of the magnetic nanoparticles (MNPs) modified with a polymer shell and functionalized by an ionic liquid or a deep eutectic solvent in aqueous biphasic systems (ABSs) is proposed. The synthesis is carried out at the interface of immiscible liquids based on aqueous solutions of polyethylene glycol and inorganic salts. The advantages of the ABSs are biocompatibility, availability, and the high solvating properties of the components, which leads to control the composition and size of the prepared MNPs. The synthesis of the Fe3O4@PEG, Fe3O4@PEG@Cyphos IL 101, and Fe3O4@PEG@TOPO/butanol MNPs has been provided for biomedical and analytical applications. The morphology and structure of MNPs have been characterized by scanning and transmission electron microscopy, thermogravimetry, X-ray diffraction, and FT-IR spectroscopy. The average diameter of the MNPs is 12–14 nm with a narrow size distribution. Their superparamagnetic nature has been described using magnetometry. The synthesis parameters have been optimized and statistically analyzed using response surface methodology. The developed approach of interfacial synthesis can be potentially scaled up and/or be used to obtain nanoparticles of various composition and application.

This work describes the development of an amperometric phosphate-selective electrode with a plasticized membrane that includes bis(2-ethylhexyl)tin (IV) dichloride as an ionophore. The potentiometric response of the plasticized membrane was investigated, in addition to its selectivity for hydrophilic anions. The membrane provided a linear potential response with respect to HPO42- ions in the concentration range from 4 center dot 10-(5) to 3 center dot 10(-2) mol/L with a Nernst slope of 29 +/- 2 mV center dot decade-1 activity. By using cyclic voltammetry, we characterized the ionophore-facilitated transfer of mono- and dihydro phosphate ions at the water/PVC-2-nitrophenyl octyl ether phase interface. An interphase distribution coefficient, a galvanic potential, a half-wave potential, the Gibbs energy of facilitated interphase transfer, as well as the Gibbs energy of facilitated interphase transfer were determined. Alternating current voltammetry was used to quantify phosphate ions in aqueous solutions. The linear response was observed in the range of phosphate concentrations from 2 to 10(-6) to 1 center dot 10(-4) mol/L and the detection limit was 8 center dot 10(-7) mol/L under these conditions. This AISE has demonstrated high selectivity for phosphate ions in comparison to the most common anions in aqueous solutions. It has been used to determine the amount of phosphates in two fertilizers.

Fe3O4@PEG have been proposed for sorption of L-lysine-alpha-oxidase (LO) from the culture fluid of Trichoderma harzianum Rifai F-180 for the first time. To synthesize the Fe3O4@PEG nanoparticles, an original method based on aqueous biphasic systems has been developed. The PEG-modified magnetite provide a high sorption ability towards LO in contrast to the non-modified Fe3O4 synthesized by the traditional precipitation method. The morphology and structure of the prepared nanoparticles were characterized by TEM, FTIR and XRD. The data on magnetic properties and stability in physiological media are presented. The synthesized nanoparticles ensure quantitative sorption and desorption of LO during at least 3 cycles.

Министерство науки и высшего образования Российской Федерации Российская академия наук Научный совет по неорганической химии РАН Научный совет по аналитической химии РАН Научный совет по химической технологии РАН Российское химическое общество имени Д.И

The review is devoted to the analysis of published data on the synthesis and use of magnetic nanoparticles modified by ionic liquids for the separation and determination of various substances in environmental samples. The main attention is paid to the determination of organic pollutants in natural waters, soils, etc. The main trends in the development of magnetic solid-phase extraction methods are noted. Methods for the synthesis of magnetic nanoparticles promising for creating new methods of sample preparation are considered.

For the first time, widespread aqueous biphasic polymer-salt extraction system was applied for selective separation of Pd(II) and Pt(IV) from chloride technological solutions by countercurrent chromatography using a rotating coiled column (an analog of centrifugal extractor). The principle novelty of the pro-posed approach is the possibility of multistage extraction process and the needlessness to add any spe-cific reagents for targeted metal binding. The results showed that the use of poly(ethylene glycol)-150 0 (PEG-150 0) as a stationary phase allows 96-100% of both Pd(II) and Pt(IV) to be recovered from chloride solutions containing copper and nickel. To obtain individual solutions of targeted metals it is enough to change the composition of the salt-rich phase for stripping stage, in particular the salt concentration and pH value. The final purity of the targeted metal fractions obtained after their extraction from model tech-nological solutions is >= 99.9%. The components of the aqueous biphasic system are recyclable, non-toxic, available, and widespread in laboratory and technology practice. A scheme of the multistage separation of platinum metals using a rotating coiled column is proposed. (c) 2021 Elsevier B.V. All rights reserved.

We proposed a method of cyclic alternating-current voltammetry with track membranes (TM) filled with ion exchangers with asymmetric pores for the determination of acetylcholine chloride (ACC). We studied the electrochemical and performance characteristics of the determination of ACC using track membranes with pores filled with nanoparticles of crushed cation and anion exchangers. Acetylcholine chloride can be determined in concentrations down to 10–6 M.

Магнитную твердофазную экстракцию (МТФЭ) широко используют в пробоподготовке при анализе различных неорганических и (био)органических материалов.Магнитные сорбенты, управляемые под действием внешнего магнитного поля, позволяют избежать стадий центрифугирования и фильтрации растворов.Использование МТФЭ открывает новые возможности для организации процесса в проточном варианте.В данном исследовании разработан новый способ синтеза магнитных наночастиц [1], позволяющий проводить одновременно модифицирование их поверхности полимерной оболочкой и ионными жидкостями.Для этих целей использовали двухфазные водные системы на основе полиэтиленгликоля (ПЭГ) и различных фазообразующих солей (сульфата, карбоната, ацетата аммония/натрия и др.).Синтез наночастиц осуществляется на границе раздела фаз полимерно-солевой системы.Экспериментально определены концентрации и соотношения прекурсоров и ионных жидкостей для получения модифицированных наночастиц магнетита, ферритов (кобальта, магния).Синтезированные сорбенты использовали для твердофазной экстракции платиновых металлов из солянокислых растворов в статических и динамических условиях.Изучена МТФЭ платины(IV) и палладия(II) в зависимости от кислотности раствора, природы и количества удерживаемой на твердой фазе ионной жидкости, времени контакта фаз/скорости пропускания раствора, исходной концентрации металлов, в том числе в присутствии других компонентов, таких как Rh(III), Au(III), Cu(II), Ni(II) и др.Разработан способ селективного выделения платины(IV) и палладия(II) с использованием сорбента на основе магнетита, модифицированного хлоридом тригексил(тетрадецил)фосфония Cyphos IL 101 (Fe3O4@ПЭГ@Cyphos IL 101), удерживаемого в колонке с помощью переменного магнитного поля (рис.):0.1 M HCl, [Pt, Pd] = 1-25 нг/мл, V = 10-20 мл, m = 0.02 г, скорость пропускания раствора 0.5-1 мл/мин, элюент 2% HNO3.Рис.Схема магнитной установки для МТФЭ

Ультразвук широко используют в пробоподготовке, в том числе для интенсификации фильтрационных, экстракционных и сорбционных процессов.Ранее нами предложен способ сорбционного концентрирования ионов металлов с использованием ультразвуковых суспензионных (УЗС) колонок [1-2], позволяющий удерживать в потоке жидкости суспензию мелкозернистого сорбента без применения фильтров.Ультразвуковое воздействие, создаваемое в колонках, влияет также на кинетику сорбции веществ за счет возникающих микротурбулентных акустических течений, которые создают условия для ускоренного протекания сорбции благодаря интенсификации массопереноса в системе сорбат-сорбент.В настоящей работе продемонстрирована возможность использования УЗС колонок (рис.)для повышения эффективности извлечения платиновых металлов на стадиях сорбции из многокомпонентных хлоридных растворов и последующей десорбции с получением индивидуальных растворов целевых компонентов.В качестве сорбента использовали силикагель Kromasil Sil, состоящий из идеально сферических частиц определенного размера (5 мкм), модифицированный фосфониевой ионной жидкостью Cyphos IL 101.Определены оптимальные условия для селективного выделения платины (IV) и палладия (II) в УЗС колонке: 0.1-1 M HCl, 10-60 г/л Cl -, содержание ионной жидкости 0.3 ммоль/г, скорость пропускания раствора 0.5 мл/мин, масса сорбента 0,02 г, интенсивность ультразвукового излучения 10 5 Вт/м 2 .Известно, что элюирование платиновых металлов обычно затруднено.Нами показано, что в условиях УЗС колонки существенно увеличивается эффективность десорбции платиновых металлов.Так, при использовании в качестве элюента перхлората натрия (0.5 М) и скорости пропускания раствора 0.2 мл/мин обеспечивается количественное извлечение металлов из фазы сорбента.Разработанная методика сорбционного концентрирования платины и палладия апробирована

Data on the influx and behavior of humus substances in natural waters are considered. The widest spread methods of analyzing physicochemical properties of natural polymers causing their interaction with metal ions are analyzed. The concept of metal complexation with humus substances at different chemical equilibria is developed on the basis of original and an available literature review evaluating the metal speciation in natural objects (lakes, rivers, seas).

The development of a principally new approach to preparation of IL-modified magnetic nanoparticles and their application as sorbent materials for recovery of platinum group metals from model technological solutions are described. The formation of Fe3O4 nanoparticles, their simultaneous coating with a polymer shell and an ionic liquid are implemented in aqueous biphasic systems by a single step synthesis. Different ionic liquids have been tested as modifying agents: Cyphos (R) IL 101, Cyphos (R) IL 110, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-octyl-3-methylimidazolium hexafluorophosphate. The prepared magnetic nanoparticles have been characterized by scanning and transmission electron microscopy, X-ray diffraction, thermogravimetric analysis and applied as sorbents for magnetic solidphase extraction of platinum metals from chloride solutions. The results indicate that the recovery of the platinum metals from (0.1 M HCl+ 1 M NaCl) solution is 99% for Pd(II) and 98% for Pt(IV) within 30 min and their quantitative stripping can be achieved using 2 M HNO3 solution.

Monitoring the quantity and quality of metals in lake water is a major part of assessing water toxicity. A fundamental aspect of geochemical monitoring studies is the evaluation of the equilibrium distribution of metal speciation in water and the influence of environmental conditions on this process. It is important to understand the difference between the behavior of nanoparticles, dissolved particles, colloid particles, and suspended particles. This study involved environmental aquatic chemistry research and the assessment of the geochemical processes of metal speciation in an arctic lake in the metallurgical waste zone and other areas where natural processes prevail. Consecutive and parallel membrane filtration methods were used to compare the results of water analysis in Imandra Lake. The membrane pore sizes were 8, 1.2, 0.45, and 0.2 µm. The following filtrate characteristics were used: microfiltration-based mechanical suspension and oxidized contaminants (>8, 1.2, 0.45, 0.2, 0.1 μm), and ultrafiltration-based colloids, bacteria, viruses, etc. (less than 0.1 μm). Industrial effluents led to the formation of higher concentrations of elements (Ni, Cu, and Pb) in their labile forms. In the wastewater-mixing zone, the concentrations of most elements were evenly distributed in depth. In more distant areas, we found a significant increase in the concentration of elements in the near-bottom horizon in comparison with the surface water (Fe by more than three times). The obtained results showed that numerous elements had diverse distributions by speciation in the points located closer to the source of wastewater. This indicated the significant influence of the adsorption process on the system balance of elements such as Fe, Cu, and rare earth elements. The impact of the regional geochemical and anthropogenic speciation and the possible influence of climatic factors on the distribution of speciation were determined.

The potential of iron oxide-based nanoparticles (IONs) as theranostic agents is believed to be in a great part due to non-invasive diagnosis and therapeutic applications. However, there is still a lack of well-recognized methodology to assess bioresistance, hypotoxicity, reactivity toward pertinent biomolecules, as well as an eventual dose of IONs as prerequisites for their clinical use. In this study, we demonstrate how application of high-resolution ICP-MS in combination with conventional ultrafiltration can address these important issues in a simple and high-throughput way. Based upon interference-free and sensitive measurements of iron and sulfur isotopes ensured by sector-field ICP-MS mode, the comparative testing of a series of novel IONs modified by PEG or PEG and an ionic liquid, was performed. Satisfactory stability (less than 1 % of soluble Fe), minor toxicity (by virtue of releasing a free iron) and transit into bioconjugates in human serum, different in speed, proved the prospective of the tested IONs for in-depth preclinical development.

For efficient extraction of cyclic amino acids, it has been proposed to use polymers based on N-vinylformamide. The extraction of phenylalanine, tyrosine, histidine, and proline in two-phase systems based on poly-N-vinylformamide and N-vinylformamide–N-vinylimidazole copolymer has been studied for the first time. Systems with the maximum recovery rate of individual amino acids have been found. The mechanism of intermolecular interactions in polymer–amino acid systems has been proposed. The results of extraction of a phenylalanine–tyrosine mixture by a N-vinylformamide–N-vinylimidazole copolymer are reported. An electrophoretic method for determining amino acids in extracts is proposed.

Issues of application of “green chemistry” principles to the extraction and separation of components of liquid mixtures have been discussed. In particular, quantitative characteristics of the interphase distribution of a number of aromatic acids in extraction systems based on polyethylene glycol and sodium sulfate have been determined. It has been shown that these systems, which do not contain components that are toxic or pose a fire hazard, are promising for the effective extraction of aromatic acids from natural and technogenic products.

Chemical composition of drinking water from different sources was studied in private farms distributed in areas of the Bryansk region contaminated by radionuclides after the Chernobyl accident. Concentration of major ions showed clear relation to water-bearing rocks and local anthropogenic contamination (e.g. N, P). Drinking water was in general impoverished in I (Ме=5.76μg/l that is below the lower limit of sanitary standard equal to 10μg/l). Thermodynamic modeling based on chemical composition of the samples showed that the predominant form of iodine is iodide and it forms mineral complexes CaI+, CaI2, MgI+, MgI2, etc. that explains iodine concentration on carbonate barrier in soils and rocks. Complexes' formation may have contributed to radioiodine retention in water during its fallout with further natural decontamination of aqueous phase during water filtration through soils and sediments enriched in carbonates and organic matter. Comparison with distribution of thyroid cancer cases among rural population revealed a tendency of the inverse relation between the number of cases and iodine content in dug well waters; the finding needs further investigation.