High-purity Substances Research Articles

Development of a coulometry system at the Korea Research Institute of Standards and Science and evaluation of the measurement uncertainty originating from the system

Coulometry is used to realize the definition of the mole and enables the direct determination of the purity of high-purity substances that are used as standards for other relative measurements with very small measurement uncertainty. However, despite several studies reporting the development of accurate and precise coulometry systems, there is a lack of detailed description of the system and systematic evaluation of the measurement uncertainty arising from the system. In this study, coulometry systems constructed at the Korea Research Institute of Standards and Science (KRISS) are described in detail and the uncertainties associated with these systems are systematically evaluated using a bottom-up approach. The relative expanded uncertainty resulting from the measurement system for the amount-of-substance content of acid in high-purity potassium hydrogen phthalate is approximately 0.0005%. The performance of the KRISS coulometry systems has been verified through several international comparisons and comparative measurements using certified reference materials.

Methods for the Continuous Chromatographic Separation of Substances

Among many versions of methods for the chromatographic separation of substances, to date, insufficient attention has been paid to their continuous separation. Among a few exceptions is a review by Maryutina and Spivakov published in 2001 [4]. Our paper deals with a more detailed consideration of the attempts made for the continuous chromatographic separation of substances and the assessment of the efficiency of the solutions found. The aim of this review was to draw more attention to this promising direction for solving two interrelated problems. First, to creating systems for the continuous analytical control of complex multicomponent samples of the composition changing with time, and, second, to solving preparative and technological problems of the separation of substances with similar chemical properties. In the first case, the method ensures studies of the dynamics of changes in the composition of complex multicomponent mixtures in studying fast chemical processes, and, when used for technological purposes, it opens up a possibility of the continuous chemical-analytical monitoring of their course from the standpoint of economic efficiency and safety. In the second case, methods of continuous chromatographic separation ensure an increase in the efficiency and productivity of obtaining valuable high-purity substances.

Melting Point Certified Reference Materials for Organic Substances: Development Perspectives

The field of the melting point measurements of high-purity organic substances today includes a large number of measuring instruments used in the field of medicine, biology, and the production of perfumery and cosmetic products.The purpose of the research is to identify the features and justify approaches to the development of melting point certified reference materials of organic substances provided with metrological traceability to the SI base measurement units «temperature» (°C).The objectives of the research included justification of the choice of substances-candidates for CRMs; determination of the certification procedure for RMs; establishment of restrictions affecting the certification procedure; estimation of uncertainty for certified values of the melting point CRMs.In the course of the research, a state analysis of metrological assurance in the field of melting point measurements was performed. An overview of the reference complex designed to measure the melting point and purity of organic substances in the range from +40 °C to +250 °C is presented, its functional diagram is given. The basic requirements for substancescandidates for CRMs are identified. The study presents the results of determining the melting point of benzophenone, benzoic acid, succinic acid, anthracene, and caffeine obtained by direct measurements of the phase transition temperature and by indirect measurements based on recording the moment of optical transparency of the substances under study. The results of interlaboratory comparisons on samples of the studied substances are presented, which made it possible to obtain reliable data on the temperature of the emergence of optical transparency at different heating rates. A method for reconciling the results is proposed; it consists in presenting the certified value of the melting point determined by the method of direct measurements of the phase transition temperature in the thermodynamic mode, as well as the certified values of the optical transparency temperature at various heating rates as additional characteristics of the substance in the passports of the developed CRMs. Research objectives for further work are formulated.The theoretical significance of the results obtained lies in the development of theoretical and methodological approaches to the certification of melting point CRMs based on pure organic substances, which make it possible to improve the measurement accuracy in the field of thermal analysis at a higher quality level.

A Thin Layer Method for the LA-ICP-MS Analysis of Trace Element Concentrates

A method is proposed for the analysis of trace element concentrates by a thin layer method in combination with inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation (LA). Trace elements concentrates were evaporated on preliminarily prepared areas of a high-purity silicon substrate, after which an LA-ICP-MS analysis was performed. The influence of the LA parameters and the conditions for recording the spectra on the signal of the analytes and the substrate material was studied. The analytical capabilities of the thin layer method in combination with LA-ICP-MS for the analysis of high-purity substances with the preconcentration of trace elements were evaluated. Using an analysis of high-purity nitric acid as an example, it was shown that the limits of detection for analytes in the LA-ICP-MS analysis of trace element concentrates using the thin layer method are in the range from n × 10–11 to n × 10–8 wt %. Thus, the development of combined procedures of analysis, including the preconcentration of trace elements and an analysis of concentrates by LA-ICP-MS, makes it possible to reduce the limits of detection for most analytes by one order of magnitude compared to instrumental ICP-MS analysis.

Модель керування рухом космічних розподілених енергетичних систем

The goal of this article is to develop a generalized mathematical model for controlling the motion of the spacecraft of a space industrial platform’s distributed power system. Space industrialization is one of the promising lines of industrial development in the world. The development of space industrial technologies will allow one to solve a number of problems in the production of unique products unavailable under terrestrial conditions. The main types of these products include semiconductor materials, materials made by 3D printing in microgravity, space modules of sunshade systems, space metallurgy products, space debris processing products, and high-purity space biology substances. Taking this into account, a certain amount of electricity is required for the manufacture of one or another product. Given that some space industrial processes can consume a significant amount of electricity, a space industrial platform's own power generation may not be sufficient. Because of this, it was proposed to use additional energy resources through the development of a distributed power supply system for a space industrial platform. A group of power spacecraft is envisaged to collect and accumulate electric energy and transmit it in a contactless way to the receivers of the space industrial platform. The article presents mathematical models for the analysis of the orbital, angular, and relative motion of power spacecraft and receiver spacecraft. Algorithms are proposed for calculating the parameters of the power spacecraft orientation and stabilization system. A generalized model is constructed for determining the maximum distance and time interval of power spacecraft to platform electric power transmission using microwave radiation. The model developed allows one to choose the power spacecraft design parameters at the stage of conceptual design of space industrial platform power systems.

Virtual Model of the Production of Chemical Reagents and High Purity Substances

Virtual Model of the Production of Chemical Reagents and High Purity Substances

Determination of the content of impurity elements in a sample of high purity India by the method of radiochemical neutron activation analysis

The present article is devoted to the development of a method for neutron activation analysis of a microimpurity composition of high-purity indium with the radiochemical separation of indium radionuclides from radionuclides of the determined elements by extraction chromatography in the system tributyl phosphate (TBP) - solutions of hydrobromic acid (HBr).Neutron activation analysis (NAA) has a special place among the physical methods for determining the trace composition of high-purity substances. Low detection limits, the possibility of simultaneous determination of a large number of impurity elements from one sample, no correction for the control experiment, the possibility of using inactive carriers in separating traces of radionuclides of impurity elements from matrix elements ensured the widespread use of NAA in the analysis of highly pure substances.The developed technique allows separating matrix radionuclides from radionuclides of impurity elements with high efficiency and determination of 28 impurity elements in high-purity indium with detection limits of 0.7 ppm to 0.05 ppb.

Use of quantitative 1H and 13C NMR to determine the purity of organic compound reference materials: a case study of standards for nitrofuran metabolites

Comparability of measurement results and their metrological traceability to the International System of Units (SI) are fundamental tools to ensure reliable decisions in the social sphere, commerce, and science. The use of appropriate references in analytical chemistry, such as certified reference materials (CRMs) of high purity substances, is one of the required procedures to obtain traceable measurements. When commercial standards with non-certified purity values are used, traceability must be achieved by determining the purity of the standard using a potential primary reference measurement procedure or other appropriate methods. Quantitative nuclear magnetic resonance (qNMR) is a technique with the potential to be used in primary measurement procedures. This work presents the determination of purity by 1H qNMR for nitrofuran metabolites 3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ), and 1-aminohydantoin (AHD). Furthermore, a recent qNMR method developed by our group to improve the quantitative performance of measurements using 13C nucleus was used to determine the purity of semicarbazide (SEM) nitrofuran metabolite. Purity values obtained by qNMR for AOZ, AMOZ, and AHD standards were compared to values obtained by the mass balance approach using a suite of analytical methods: Karl Fischer (KF) coulometric titration and thermogravimetry (TG) for the determination of water and residual solvents, gas and liquid chromatography for the determination of impurities structurally related to the metabolites. The results obtained by qNMR and mass balance were consistent.Graphical abstract.

Preface

The International Conference on Functional Nanomaterials and High-Purity Substances is major scientific forum traditionally organized every two years. The present 8th Conference, as usually, covers fundamentals of designing functional, in particular, high-purity metallic, ceramic, and composite nanomaterials and materials, technological basis for their manufacturing, problems of their analysis, and applications. The Conference provides opportunities for the attendees to exchange new ideas and application experience, to establish scientific relations, and to find partners for mutually beneficial collaborations.The main directions of the Conference are: magnetic materials and systems; composite materials, including polymer compositions; and functional inorganic materials, including high purity and single-crystal. Dimensional, structural and impurity factors in the materials science and engineering developments, methods for studying functional metallic, ceramic and composite materials are discussed. Rare-earth metals, their resources, preparation, purification, designing rare-earth-containing functional materials are in the focus of the present Conference. Information about innovative technologies in powder and granule-metallurgy materials and structure and properties of carbon composite structural materials as well are widely presented and considered in terms of the Conference.Along with plenary and section presentations, school conference for young scientists, and extensive poster sessions, round-table meetings are held and allow the participants to discuss promising projects in the field of the development of novel functional nanomaterials and their efficient applications.Duration of plenary reports - 30 minutes, invited reports - 20 minutes, sectional presentations - 15 minutes, reports within the framework of the Youth School - 10 minutes. In total, 253 presentations (167 - oral and 86 - poster) were presented. 35 reports were submitted by young scientists.

Separation and purification of tantalum from plumbomicrolite of amazonite deposit in Kola Peninsula by acid leaching and solvent extraction

A plumbomicrolite concentrate (PMC) was leached with the mixture of HF and H2SO4, HF and HNO3 acids, respectively. Optimal conditions ensuring high recovery of tantalum and niobium (up to 99%) into solution, and radionuclides into insoluble residue were determined. Fluoride-sulfuric acid and fluoride-nitric acid schemes were proposed for PMC leaching by an extractive separation of tantalum form niobium, lead and impurities, and production of high-purity tantalum compounds. Octanol-1 was used as an extractant. Optimal conditions for production of high-purity tantalum strip solutions were defined for all stages (extraction-scrubbing-stripping). Produced tantalum compounds, such as tantalum pentoxide and potassium heptafluotanthalate, comply with the norms for high-purity substances in terms of impurities content. Final choice of the PMC processing scheme is determined by its profitability.

Preparative separation of high-purity troxerutin and related substances from mother liquor of troxerutin by silica gel column chromatography and semi-preparative liquid chromatography

Preparative separation of high-purity troxerutin and related substances from mother liquor of troxerutin by silica gel column chromatography and semi-preparative liquid chromatography

High purity substances – prototypes of elements of Periodic Table

Abstract The Mendeleev Periodic Table of Chemical Elements delivered a strong impetus to the development of fundamental and applied chemistry, chemical technology, analytical chemistry, and material sciences. Each element under the Periodic Table is an idealized substance with a certain structure and properties as defined by existing theoretical frameworks. In the real world, we deal with substances that are close in composition to the element of Periodic Table under study but differ in the presence of different elements in them – impurities that distort (sometimes radically) the structure and properties of the target research object. For many centuries, humanity has sought to obtain pure substances in order to achieve desired properties. In the second half of the 20th century, a unique collection of high purity substances was created, which includes samples representing material artifacts, prototypes of elements of Periodic Table that contain record low contents of impurity elements. With ongoing scientific and technological progress, the achieved purity of substances continuously increases and, therefore, their approximation to idealized elements of Periodic Table. This is facilitated by: new technological processes for the production and storage of high purity substances with a constant decrease in the level of impurities; the creation of isotope-friendly substances; complexes of more highly sensitive multi-element analysis methods; identification of the unique properties of high purity substances, bringing them closer to the capabilities of analog elements of Periodic Table and much more. This article is devoted to progress in these areas. Special attention is also paid to the problems in modern analytical chemistry of high purity substances and the use of the latter in the metrology of chemical analysis as the standards of comparison.

Impurity Composition and Lattice Parameters of High-Purity α-Mn

We have studied a high-purity manganese sample provided by the Exhibition–Collection of Extrapure Substances, operating on the basis of the Devyatykh Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, and analyzed for the concentration and trace levels of 59 elemental impurities. The content of the major component in it was 99.9993 wt %. Its growth surface was formed by intergrown and individual single crystals, from which samples for lattice parameter measurements were cut. Precision measurements were performed at room temperature (298 ± 1 K) over the entire Ewald sphere on an XCalibur four-circle diffractometer (Rigaku-Oxford Diffraction). The lattice parameters of single-crystal samples selected for measurements were determined using high-angle reflections. The unit-cell dimension of our samples turned out to exceed those reported previously by different groups for poly- and monocrystalline manganese samples.

PHASE EQUILIBRIUM IN THE Cu2Se – SnSe2 – As2Se3 QUASITERNARY SYSTEM

77 alloys have been synthesized to study the interaction of the components in the Cu 2 Se –SnSe 2 – As 2 Se 3 quasi-ternary system. The synthesis was carried out by direct single-temperature method from high purity substances (Cu – 99.99 wt.%, Sn – 99.99 wt.%, Se – 99.9997 wt.%, As – 99.9999 wt.%) in evacuated and sealed quartz ampoules. The maximum temperature of the synthesis was 1170 K, homogenizing annealing was carried out at 510 K during 600 h. The obtained samples were investigated by X-ray analysis and differential thermal analysis. The isothermal section of the system at 510 K has been constructed based on the results of the X-ray analysis. The quasi-binary equilibria Cu 2 SnSe 3 – CuAsSe 2 ; Cu 2 GeSe 3 – As 2 Se 3 divide the quasi-ternary system into 3 subsystems: Cu 2 Se – Cu 2 SnSe 3 – CuAsSe 2 ; CuAsSe 2 – Cu 2 SnSe 3 – As 2 Se 3 and Cu 2 SnSe 3 – SnSe 2 – As 2 Se 3 . Solid solutions with large length are not formed, solubilities based on binary, ternary compounds are not more than 5 mol. %. The liquid surface projection of the Cu 2 Se – SnSe 2 – As 2 Se 3 quasi-ternary system has been built based on the literary and obtained results of investigations of the four polythermal sections and one phase diagram. The projection consists of the fields of primary crystallization of Cu 2 Se, Cu 2 SnSe 3 , SnSe 2 , As 2 Se 3 , CuAsSe 2 . They are separated by 8 monovariant curves and 9 nonvariant points. The Cu 2 SnSe 3 – As 2 Se 3 section is quasi-binary and it devides the investigated system into two subsystems: Cu 2 Se – Cu 2 SnSe 3 – As 2 Se 3 (I) and Cu 2 SnSe 3 – As 2 Se 3 – SnSe 2 (II). In the subsystem (I) two nonvariant processes take place:L U1 + Cu 2 Se ↔ Cu 2 SnSe 3 + CuAsSe 2 (peritectic) at 700 K and L E1 ↔ As 2 Se 3 + CuAsSe 2 + Cu 2 SnSe 3 (eutectic) at 600 К. In the subsystem (II) one nonvariant eutectic process L E2 ↔ As 2 Se 3 + Cu 2 SnSe 3 + SnSe 2 takes place at 610 К.

HIGH PURE SUBSTANCES FOR ASTROPHYSICAL RESEARCH

The features of the application of high-purity substances for studying rare nuclear events in astrophysics, in particular double beta decay, are considered. It was noted that for such studies, the special underground laboratories are needed to eliminate the cosmic radiation background, and the use of high-purity materials for possibility to record rare nuclear events. The content of neutral impurity elements should not exceed 0.1 ppm, and the level of radionuclide contamination should be less than units mBq/kg. At the NSC KIPT, the technologies have been developed for the production of high-purity refractory (W, Mo, Re, Ru, Os) and low-melting metals (Zn, Cd, Te, archPb), including isotopically-enriched 106Cd, 116Cd, satisfying these requirements. Using these metals both as individual elements and as part of low-background scintillation single crystals, it was possible to obtain a number of new fundamental results in the field of astrophysics, together with the Institute for Nuclear Research of the National Academy of Sciences of Ukraine and the Gran Sasso Laboratory of the National Institute of Physics (Italy)

Determination of matrix composition of Ge-Se-Te chalcogenide glasses using the ICP-AES method

One of the most important stages of the high-purity chalcogenide glasses’ analytical control is the determination of matrix elements’ content with the uncertainty at the levels of 0.1–0.2 mol.%. The content of the macro-components may differ from the composition of the initial charge; therefore, an important task is the macro-composition determination of the final materials. This article describes the development of the technique for determining the matrix elements of high-purity Ge-Se-Te glasses in the range of germanium content from 10 to 35 mol. %, selenium and tellurium content from 20 to 50 mol. % with the expanded uncertainty within 0.01–0.2 mol. % (P = 0.95) using the inductively coupled plasma atomic emission spectrometry (ICP-AES). A simple technique for the preparation of primary calibration solutions from pure elementary Ge, Se and Te is proposed. The correctness of the analysis results is confirmed by comparing the calculated matrix composition of model glass samples, prepared by direct synthesis from high-purity simple substances in the sealed quartz glass ampoule, with the analysis results. The main advantage of the proposed analysis technique is the absence of the need for the reference samples identical to the analyzed material, which is especially important for determination of new materials’ matrix composition. The minimum sample mass for the determination of matrix elements is about 1 mg, which makes it possible to analyze not only bulk glass samples, but also fibers and expensive materials.

XV International Russian-Chinese Symposium “Advanced Materials and Processes”

The publication includes works presented at the XV International Russian-Chinese Symposium “Advanced Materials and Processes” (October 16-19, 2019, Sochi, Russia). From the Russian side, the organizers of the Symposium are Russian Foundation for Basic Research, Baikov Institute of Metallurgy and Materials Science of the Russian Academy of Sciences (IMET RAS), Federal Research Center “Crystallography and Photonics” RAS, Institute of Strength Physics and Materials Science of the Siberian Branch of the Russian Academy of Sciences. From the Chinese side are the Chinese Academy of Engineering, the Chinese Academy of Sciences, the Chinese Nonferrous Metals Industry Association, the Nonferrous Metals Society of China, and Beijing Central Institute of Nonferrous Metals.The symposium has been regularly held since 1991, once every two years, alternately in Russia and China. The Symposium program covers all relevant areas of modern materials science in the field of fundamental and applied research and development of new advanced materials and technologies.The presented works are devoted to the study of metal, ceramic and composite materials for aviation and space technology, energy technology, electronics, energy-saving and “green” technologies. The issues of development of the structural and functional materials with special properties, biomedical materials, catalysts, as well as the use of rare metals and high-purity substances are considered. The results of recent advances in the development of laser-information and additive technologies for the manufacture of the products of complex configuration are presented.All the papers have been peer reviewed and recommended for publication by the Symposium Program Committee.The Symposium was organized with the support of the Russian Foundation for Basic Research, project No. 19-03-20042.

Physicochemical and Methodological Approaches to the Development of Integrated Processes for the Preparation of High-Purity Substances

This paper summarizes results of studies aimed at developing physicochemical and scientific methodological principles of the preparation of high-purity substances by integrated technological processes. We rely on the identification and chemical transformations of impurities in the recovery from raw materials, synthesis, and ultrapurification of substances by various methods. A scientific methodological approach has been developed for choosing and substantiating integrated processes for the preparation of extrapure-grade (6N or 7N) compounds with a total content of trace impurities from 0.1 to 1 ppm by weight from standard and unconventional raw materials. We have obtained batches of high-purity arsenic- and gallium-containing substances and tested them in the technology of advanced microelectronic and optical materials.

Countercurrent Chromatography in Elemental Analysis: From Oil to High-Purity Substances

The capabilities of countercurrent chromatography (CCC) in the elemental analysis of samples with different chemical and phase compositions are demonstrated. The combination of the characteristic features of extraction chromatography and multistage extraction with separation and preconcentration processes performed in a closed system (a Teflon coiled column) opens up prospects for applying this method to the analysis of a wide range of materials from high-purity substances to oil and rocks. The use of CCC at the stage of sample preparation makes it possible to decrease the detection limits of impurity elements in high-purity materials to a pg/g level, i.e., by two or three orders of magnitude, as compared with those in the direct determination by inductively coupled plasma mass spectrometry. In the analysis of oil samples, CCC allows one to determine their complete trace element composition (including platinum group, rare, and rare earth elements) due to the concentration of trace elements in a small volume of a stationary aqueous phase retained in the column.

Redefinition of the mole and uncertainty of analytical measurements

Redefinition of the basic units of the International System of Units (SI) — the kilogram, mole, ampere, and kelvin, — which are now expressed in terms of fundamental physical constants means a substantial revision of the system. In particular, the new definition of the mole fixing the value of the Avogadro constant sets a unit of the amount of substance, which is independent of the unit of mass. We consider some consequences of redefining (the mole and kilogram) and focus on the uncertainty of measuring the amount of substance and related quantities which are important for description of the mixture composition. The issue regarding the molar mass of the substance and associated uncertainty is considered in detail It is noted that calculation of the molar mass using relative atomic masses, involves the molar mass constant which is not equal exactly to 1 g/'mol in the new SI. This introduces an additional, though very small, uncertainty of less than 1 x 10-9in relative terms. The budget of uncertainty for the amount of substance determined through the mass measurements when the mass is measured with the highest accuracy is scrutinized. It is demonstrated that for substances of less than 99.98% purity, the uncertainty associated to the purity is comparable to that of relative atomic masses of the elements. For high-purity substances, the uncertainty in the relative atomic masses have the largest contribution to the budget. Anyhow, the uncertainty associated to the molar mass constant is three orders of magnitude less than the nearest contribution to the uncertainty attributed to weighing. In the case of derived quantities which are the ratio of two quantities of the same kind, the additional uncertainty does not arise at all. This is illustrated by the calculation of the mole fraction of a component in the gravimetrically prepared gas mixture.