Analytical Lines Research Articles

Determination of trace amounts of uranium in plutonium oxide by wavelength dispersive X-ray fluorescence spectrometry

This paper presents a wavelength dispersive X-ray fluorescence (WDXRF) spectrometry based non-destructive methodology for the determination of trace level uranium in PuO2 powder. The methodology requires pelletization of PuO2 powder standards and samples using a hydraulic press, measuring WDXRF spectra of calibration standards and samples using U Lα X-ray as analytical line and analyzing the samples for trace amounts of uranium. The reproducibility of the analytical results using this methodolgy was found to be better than ± 5% (RSD, n = 5) for uranium in the range of 200–1000 µg g−1. The samples were also analyzed for U by ICP-OES and WDXRF values showed a close agreement with those obtained by ICP-OES.

An image features assisted line selection method in laser-induced breakdown spectroscopy

Analytical lines play a crucial role in laser-induced breakdown spectroscopy (LIBS) technology. To improve the classification performance of LIBS, an image features assisted line selection (IFALS) method which based on spectral morphology and the characteristics of Harris corners was proposed. With this method, a classification experiment for 24 metamorphic rock samples was conducted with linear discriminant analysis (LDA) algorithm. The result showed that the classification accuracy was increased from 94.38% of the conventional classification model MLS-LDA (Manual line selection-linear discriminant analysis) to 98.54% of IFALS-LDA. Furthermore, the time required for the whole classification process was decreased from 2768.38 s of MLS-LDA to 4.36 s of the proposed method, thus the classification efficiency was greatly improved. In addition, compared with the existing automatic line selection method, the convergence rate of IFALS-LDA is significantly faster than that of ASPI (Automatic spectral peaks identification)-LDA. This study demonstrates that LIBS assisted with the image features in machine vision can promote the analytical performance of LIBS technology.

Determination of platinum group elements in catalysts recycling products by SEM with energy dispersive spectrometer

Analysis of platinum group elements (PGE) extracted from various catalysts used in the car, petroleum and chemical industries requires use of microanalytical methods. PGE content in the platinum powder concentrates K176 and K177 was studied by SEM-EDS. The content of main elements was determined using analytical lines Fe Kα1, Si Kα1, Sn Lα1, Pt Lα1, Re Lα1. The obtained data for the chemical composition are in good agreement with the result obtained by X-ray fluorescence analysis and ICP-MS method. Powdered platinum concentrates are considered to be ferrosilicide (FeSi), where PGE are localized at the phase boundaries and in separate patches of the K176 sample, or distributed over the volume of particles in the K177 sample.

Evaluation of the Characteristics of X-Ray Excitation under the Electron-Probe Effect Using 2D and 3D Modeling by the Monte Carlo Method

The results of the two- and three-dimensional modeling of X-ray excitation during electron-probe microanalysis by the Monte Carlo method are compared. The study is based on a description of the X-ray distribution in pure elements such as Cu, Ag, and Au, which are of interest in the exploration of minerals at gold ore deposits. The absorption corrections calculated using the Monte Carlo models for 2D and 3D x-ray distribution over the sample depth are compared. For electrons with an energy of about 3 keV and more, calculations of the absorption factor for 2D modeling are in satisfactory agreement with those for 3D modeling. The functions of the radial and lateral x-ray distribution in the sample, which characterize the spatial resolution of electron-probe microanalysis, are constructed. The obtained approximations make it possible to estimate the resolution for elements which are generally determined by analytical lines of the K series and for some elements which are determined by L-series lines.

Evaluation of the Zr, Y, and Gd Contents in Targets for Magnetron Spraying of Heat-Shielding Coatings Based on Zirconium

We proposed a method for the evaluation of the mass fraction of zirconium and rare-earth metals by the method of atomic-emission spectrometry with inductively bound plasma in zirconium-based alloys and ligatures. The proposed procedure includes the preliminary microwave preparation of samples of zirconium alloys and the choice of analytical lines for detection of elements of the alloy. We perform the choice of the composition of mixture for dissolution and the parameters of microwave decomposition and establish the main and alternative analytical lines of emission of the detected elements free of significant spectral overlays. The metrological characteristics of the method aimed at the evaluation of the mass fractions of zirconium and rare-earth metals are evaluated. The limits of the relative errors of measurements of the mass fractions of elements within the range 1–90% do not exceed ±2% with a confidence probability P = 0.95.

Relationship Performance of Cylindrical Detention Pond (CDP) as Depression Storage and Runoff Reduction Under Fully Saturated Condition

Permeable pavements are a key Storm water management measure employed both to attenuate surface runoff in urban areas and to filter urban storm water pollutants. Existing permeable pavements (PP) are design with the specific percentage porosity whereby enabling excess rainwater to infiltrate through the system and acting as a depression storage at the same time. Depression storage basically refers to the volume of water trapped in the depression when the precipitation of a storm reaches the ground and filled up all the depression before it can flow over the surface. Cylindrical Detention Pond (CDP) is an alternative paving material that may alleviate many of the hydrological problems caused by urban runoff from developed areas. CDP consist of three basic component; top cover, bottom cover and hollow cylindrical at centre (300 mm thickness). The hollow cylindrical has approximate 50 percent porosity from the total solid of component, which is every 1 inch (25 mm) of pavement depth can hold 0.5 inches (12.5 mm) of rain in theoretical. In this study, the depression storage rate of CDP was investigated under three different rainfall intensity scenarios which are 77 mm/hr (low), 153 mm/hr (medium), and 230 mm/hr (heavy) respectively whereby it function to monitoring the analytical trend line. The experiment was conducted in model box in the laboratory under fully saturated condition. It found that the CDP can performed to detent the water until 180 min of excess rainfall for all 2 year ARI, 5 year ARI, 10 year ARI, 20 year ARI, 50 year ARI and 100 year ARI with different rates. CDP’s able to reduce the runoff up to 77% of the total rainfall volume. The result was proved the hollow cylindrical at centre of CDP very effective in runoff volume reduction according to the different ARI trend line projection.

Account of Mutual Element Interference in the Analysis of Thin Bilayer V−Cr Systems by X-Ray Fluorescence

A method is proposed for the determination of the surface density of layers in the X-ray fluorescence analysis of bilayer V−Cr systems on polikor substrates. Easy-to-make unified film layers obtained by the deposition of vanadium on polymer film substrates are used. Correction coefficients taking into account the level of intensity attenuation of the primary radiation of an X-ray tube and of the analytical line of an element of the lower layer in the upper layer, and also the enhancement of the fluorescence intensity of atoms of the upper layer by the radiation of atoms of the lower layer are calculated.

Determination of modifying additives and impurities in Nb – Si-based composites using inductively coupled plasma atomic emission spectrometry (ICP AES)

The evolutionary development of structural heat-resistant superalloys has led to creation of high-temperature niobium-silicon based natural composite materials (CM) which are promising for manufacturing of aircraft gas turbine engine blades with an operating temperature of up to 1350°C. To impart the necessary properties (heat resistance, heat resistance, creep resistance, fracture toughness, manufacturability, etc.) CM are doped with modifiers, e.g., B, Ge, Sn, Zr. When using the technology of mechanical alloying for production of niobium-silicon based composites Fe and Ni can enter the material as technical impurities. The quality of materials is the first concern in the aerospace industry. Accurate determination the matrix, alloying and impurity elements in the CM composition is necessary for quality control of the semi-products and off-the-shelf CM. We improved the method of ICP AES with microwave sample preparation for determination of the chemical composition of niobium-silicon based composite materials. The analytical lines of B, Ge, Sn, Zr, Fe, and Ni free of significant spectral overlap are used. The range of the determinable contents (wt.%) is: Nb — 40 – 80; B, Ge, Zr — 1 – 5; Sn — 1 – 2.5; Fe — 0.01 – 10; Ni — 0.01 – 5. To evaluate the metrological characteristics of the method, model solutions similar in composition to the composites analyzed, prepared from certified solutions of the ions, were used as reference samples. State standard reference samples of ferroniobium and titanium alloys similar in composition to Nb – Si based CM were used to verify the accuracy of the technique in spiked tests. The repeatability and intermediate precision indices did not exceed 2 and 4 %rel., respectively, for all the elements studied.

Quantification of heavy metals in oils with µL volume by laser induced breakdown spectroscopy and minimazing of the matrix effect

In this work we describe a method for preparation and analysis of oils by Laser Induced Breakdown Spectroscopy (LIBS), aimed to minimize the necessary sample volume and the matrix effect while maximizing the detection sensitivity and measurement's repeatability. The preparation procedure consists in stabilizing the oil sample and silica wafer substrate at a fixed temperature, here of 40 °C, and in delivering an oil droplet on the wafer rotated by a spin coater. In this way, a uniform oil film is obtained, which thickness is controlled through the rotation speed. So prepared target is then scanned by using the LIBS instrument. From comparative measurements on the pure oil and oil containing 2100 ppm of various elements, we studied different potentials sources of the matrix effect. During the sample preparation, above a certain rotation speed the thickness of the liquid film is the same for the two oils although their kinematic viscosities are very different, meaning that the volume sampled by LIBS is the same. The measured oil transmissivity at the laser wavelength of 1064 nm significantly decreases with concentration of impurities, but this effect could be neglected when dealing with very thin films. The plasma formation threshold measured on the bulk oil samples decreases with the impurity content. In case of pure oil, also for the maximum laser energy here used (165 mJ), the plasma is mainly initiated on the wafer while the presence of impurities increases screening of the substrate by the plasma formed directly on the oil. The matrix effect disappears on a very thin film, here of 0.74 μm, where the C I line intensity in plasma does not vary with the total concentration of impurities between zero and 2100 ppm; simultaneously, the plasma emission becomes stable from one laser pulse to another, contrary to the case of a thick liquid layer. At 0.5 μs from the laser pulse the plasma electron density is much higher in presence of oil than on the bare substrate because of the initial plume confinement. In the optimized experimental conditions the plasma emission from oil was very intense although the sample volume probed by each laser pulse was of 0.3 nL only. By choosing properly the signal acquisition delay and the calibration procedure, the latter is dependent on the excitation energy of the analytical lines, we obtained the detection limits of 3.9 ppm, 0.49 ppm, 0.16 ppm and 0.082 ppm for Zn, Cd, Cu and Cr in oil, respectively.

Book review for a book by J. Willis, C. Feather и K. Turner “Guidelines for XRF Analysis. Setting up programmes for WDXRF and EDXRF”. Printed in South Africa by Shumani Mills Communications”, 2014, 519 pp. ISBN 978-0-620-62961-4

X-ray fluorescence analysis finds wide application in various fields of knowledge and industries. One of the features of the development of the method at the present stage is a significant excess of the production of X-ray spectrometers in comparison with the training of specialists who have the knowledge for the competent use of equipment. As a result, manuals and reference books are of great importance, which help to correctly choose the optimal conditions for measuring the intensities of the analytical lines of the elements to be determined and methods of converting the experimental intensities into concentrations. The paper provides information about the book by M.J. Willis, C. Feather and K. Turner “Guidelines for XRF Analysis. Setting up programs for WDXRF and EDXRF”. The material is presented on 518 pages, illustrated with 250 figures and contains 131 tables. The review discusses the material presented in chapters. The first 7 chapters of the book provide information on the theoretical and technical foundations of XRF. In the most voluminous sixth chapter “Setting up an Analytical Programme”, information on the aspects of the choice of instrumental parameters, analytical lines, angular positions for evaluating the background intensity and the contribution of spectral overlaps is consistently presented. The second section discusses recommendations for the selection of analytical parameters for investigating the concentrations of individual elements from F to U, usually determined using XRF at the trace level (Chapters 8-15). In the third section, the authors similarly considered recommendations for the selection of analytical parameters for investigating the concentrations of individual elements for specific typical materials (chapters 17-31). The authors have prepared a good quality reference guide useful for both beginners and skilled professionals.

Химический анализ зоопланктона методом лазерно-искровой эмиссионной спектроскопии без использования образцов сравнения

This study deals with the determination of ratios of light metals (Li, Na, K, Mg, and Ca) in zooplankton (Calanus spp.) by calibration free laser-induced breakdown spectroscopy, assuming local thermodynamic equilibrium. The temperature of laser-induced plasma of zooplankton was derived from rotation-vibration bands of CN, and the electron density was calculated by Stark broadening of Mg I 383.23 nm, Li I 610.37 nm, and Ca II 396.85 nm lines. The synthetic spectra calculated with a radiation transport model for the experimental values of T and Ne were used for a selection of analytical atomic lines free from self-absorption. We compared the obtained data with the results of atomic emission and mass spectrometry with inductively coupled plasma. We also discussed the influence of ionization equilibrium on the accuracy of the results. We propose the presented method for direct semi-quantitative determination of Li, Mg, and Ca ratios in zooplankton.

Comparison of sample preparation techniques and matrix effects correction methods for X-ray fluorescence determination of total iron and rock-forming elements in iron ores

The genesis of deposits determines wide variations in the mineral and chemical composition of iron ores. It is necessary to determine the content of not only the main ore element (Fe), but also the main rock-forming elements, especially those that affect the quality of the product obtained from the ore (for example, P and Mn). When determining Fe, Mg, Al, Si, P, Ca, Ti, and Mn in iron ores by wavelength-dispersive X-ray fluorescence analysis, two common sample preparation techniques were compared: pressing powder samples on a boric acid substrate and homogenization of calcined sample by fusion with lithium tetraborate. For each method, the repeatability of the measurement of analytical lines was evaluated, calibration equations were constructed using certified reference materials of iron ores of various types and two methods for matrix effects correction (fundamental parameters and empirical intensities) were compared. Iron ores samples from the Korshunovskoye, Rudnogorskoye and Tatyaninskoye deposits of the Angarsk ore province (north of the Irkutsk region and southeast of the Krasnoyarsk Krai) were analyzed by the certified atomic absorption and spectrophotometric techniques, and the results were compared with those obtained by X-ray fluorescence analysis. For the main ore element (Fe) and some rock-forming elements (Mg, Al, Si, P) determination, the fusion technique provided a smaller error, however, both techniques could be used to determine Ca, Ti, and Mn. The choice of the sample preparation technique for wavelength-dispersive X-ray fluorescence analysis of iron ores should be based on the appropriateness of the financial and labor costs and the necessary accuracy of the analysis. Keywords : wavelength-dispersive X-ray fluorescence analysis, iron ores, rock-forming elements, borate glasses, matrix effects correction DOI: http://dx.doi.org/10.15826/analitika.2020.24.2.005 Victor M. Chubarov 1 , Elena I. Borkhonova 2 , Alena A. Amosova 1 1 Vinogradov Institute of Geochemistry, SB RAS, 1 А Favorsky st., Irkutsk 664033, Russian Federation 2 Irkutsk State University, 1 Karl Marx st., Irkutsk 664003, Russian Federation

激光诱导击穿光谱中分析谱线的自适应选择方法

激光诱导击穿光谱中分析谱线的自适应选择方法

Age-gender mortality study on alcohol-induced deaths in Slovakia.

Alcohol use is one of the ten most common risk factors threatening global health that is avoidable (ranked fifth after smoking). It is involved in high rates of liver cirrhosis, epilepsy, hypertension, cerebrovascular and mental illness. Negative consequences of family and social drinking are also very significant. The aim of the study is to quantify the gender and age-differentiated disparities in alcohol-related mortality in the population over 16 years between the years 1996-2017 in Slovakia. We used data from mortality reports within 1996-2017 provided by the National Health Information Centre in the Slovak Republic. We applied two-dimensional correspondence analysis where dimensions are age and chosen causes of deaths induced by use of alcohol and classified by the International Classification of Diseases. In case of males, we found that K74 - Fibrosis and cirrhosis of liver diagnosis almost perfectly corresponds to age 66-75 years, and we documented strong correspondence between K70 - Alcoholic liver disease and age 46-55 years. For females, the most robust finding is that K70 - Alcoholic liver disease corresponds relatively similarly with age groups 26-35, 36-45, 46-55. The results of the analysis allow us to obtain a detailed overview of the development of mortality in individual alcohol diagnoses and their intervention in individual age groups by gender. Mortality for some diagnoses affects the young female as well as male population. We observed that there are systematic differences in alcohol-induced mortality between males and females. In such development of the alcohol-related mortality structure, the priority remains the permanent provision of primary, secondary and tertiary prevention at the individual and population level. The results of our analysis represent a valuable platform for health and social policymakers to develop quality national and regional health strategies aimed at eliminating the consequences of alcohol use. Lessons learned from our analysis will be supported by our other geographically oriented analytical lines to link identified and quantified regional disparities in the mortality of alcohol diagnoses to the availability of health care to treat these diseases.

Carbon analysis of steel using compact spectrometer and passively Q-switched laser for laser-induced breakdown spectroscopy.

Laser-induced breakdown spectroscopy (LIBS) is carried out with compact 1064 nm laser and spectrometer components which are suitable for handheld applications. Bursts of ∼0.6 mJ, 5 ns laser pulses are generated by a passively Q-switched laser with a 1 kHz triggered pump diode. The miniature spectrometer with a set wavelength range of ∼188-251 nm has an instrumental broadening at the carbon analyte line, C I 193.09 nm, of less than 36 pm. Analytical calibration curves of C, as well as Cr, Ni, and Si are taken with certified reference samples of iron and steel in an argon purged setup. The net duration of the laser bursts is ∼0.7-1.4 s for a measurement, depending on the number of repetitions on the sample surface. The limit of detection (LOD) is determined to a mass fraction of 34 µg/g for C. High-alloy steels 1.4306 (0.01% C) and 1.4541 (0.035% C) are separated clearly by the LIBS measurement of carbon.

Analysis of Yttria-Stabilized Zirconia by Inductively Coupled Plasma Atomic Emission Spectrometry

A method for determination of aluminum, hafnium, iron, yttrium, calcium, magnesium, and titanium by inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. Conditions for the decomposition of two modifications of the analyzed material—unburnt and subjected to stabilizing firing—have been studied. It has been found that the unburnt zirconia dissolves in sulfuric acid, and the burnt sample can be converted to solution only by fusing with potassium pyrosulfate or potassium bifluoride. However, the application of these reagents leads to high values of the control experiment correction for trace impurities (at the level of tenths and hundredths of a percent). In this connection, we have studied the possibility of acid dissolution of the burnt sample under microwave decomposition, varying the qualitative and quantitative composition of the acid mixture, reaction temperature, and time to reach and maintain the required temperature. It has been found that the decomposition in the mixture of hydrofluoric and sulfuric acids (2 : 1) in the microwave system with stepwise heating of the reaction mixture ensures quantitative dissolution of the burnt sample and sufficiently low values of the control experiment correction for trace impurities. The analytical lines have been chosen taking into account their relative intensity, possible spectral overlaps, and the matrix effect in the analysis of model solutions containing 1.3 mg/cm3 Zr, 0.2 mg/cm3 Y, and from 0.2 to 20 mg/cm3 impurities. As a result, the following analytical lines have been chosen: Al II 167.079 nm and Al I 308.215 nm, Ca II 184.006 nm and 393.366 nm, Fe II 238.204 nm, Mg II 279.553 nm, Ti II 334.941 nm, Y II 371.030 nm, and Hf II 232.247 nm. The developed method for the analysis of yttria-stabilized zirconia by ICP-AES allows simultaneously determining aluminum, iron, magnesium, and titanium in the range of 0.01–1.0%; calcium, 0.02–1.0%; hafnium, 0.1–5.0%; and yttrium, 2.0–15% with a relative standard deviation of 6–30 rel % (for Al, Fe, Mg, Ti, and Ca), 2–7 rel % (Hg), and 2–4 rel % (Y). The correctness of the method is confirmed by the standard addition technique.

Arc Atomic Emission Analysis of Rare Earth Metals and Their Oxides with Preliminary Sorption Concentration of Impurities

This work investigates in analytical capacities of arc atomic emission analysis (AAEA) in determination of As, Bi, Sb, Cu, and Te in rare earth metals (REM) and their oxides after preliminary group concentration using S,N-containing heterochain polymer sorbent. The investigations have been carried out using a Grand-Extra high-resolution spectrometer developed by VMK-Optoelektronika (Russia). Sorption kinetics and impurity extraction rate as a function of solution acidity have been studied for a selection of conditions of sorption concentration. Aiming at optimization of arc atomic emission detection of As, Bi, Sb, Cu, and Te, various flowcharts of their sorption concentration and subsequent treatment of obtained concentrated product have been considered with addition of a collector at various sorption stages. Powdered graphite has been used in this work as a collector in analysis of rare earth oxides, which is attributed to the relative simplicity of its emission spectrum and versatility. Analytical conditions and spectrometer parameters affecting the analytical signal (sample weight and composition, shape and size of electrodes, current intensity and operating mode of generator, interelectrode distance, wavelengths of analytical lines) have been selected. The evaporation curves of detected impurities have been analyzed, and the exposure time of As, Bi, Sb, Cu, and Te in the obtained sorption concentrate has been determined. Accuracy of the results has been evaluated using reference samples and by comparisons between methods. The results have been used for development of arc chemical atomic emission analysis of yttrium, gadolinium, neodymium, europium, scandium, and their oxides in the concentration range of n × (10–5–10–2) wt %.

Analysis of Corrosion-Resistant Ruthenium-Doped Titanium Alloys by Inductively Coupled Plasma Atomic Emission Spectroscopy

A technique for analyzing new corrosion-resistant ruthenium-doped titanium alloys using inductively coupled plasma atomic emission spectrometry (ICP-AES) with microwave sample preparation is reported. The composition of a mixture of acids and the temperature and time parameters of sample preparation of titanium alloys under microwave heating in an autoclave ensuring quantitative conversion of the sample into a convenient analytical form without loss of volatile components for subsequent ICP-AES analysis are substantiated. Optimal conditions for the excitation of the analytical signal have been found, and analytical lines of elements without spectral noise have been selected. Samples of experimental melts of industrial titanium alloys of various classes, volumetrically doped with ruthenium, which are under development and are not yet commercially produced in the Russian Federation (alloy PT-7M + Ru, PT-3B + Ru, 5B + Ru, 37 + Ru, VT-22 + Ru) have been studied. The alloy samples contained the following alloying elements (wt %): Al (1.8–6.3); V (1.0–5.5); Mo (0.7–5.5); Zr (0.2–3.0); Cr (0.5–1.5); Fe (0.5–1.5); Ru (0.05–0.15). The correctness of the determination of alloying elements has been confirmed by analyzing standard samples by varying their mass and, in the case of ruthenium, by the “introduced–found” method. The developed method significantly reduces the time of analysis by combining the multielement ICP-AES method with microwave sample preparation, expands the list of detectable elements in titanium alloys, and improves the precision of the results of analysis.

The effects of multipactor on the quality of a complex signal propagating in a transmission line

Multipactor is a much studied resonant AC discharge that is harmful to microwave components and circuits. There is substantial current interest in this topic because of its threat to satellite communications. In this paper, an analytical transmission line model is presented to assess the effects of multipactor, should it happen, on the distortion of a signal. The model is applicable to any input signal (analog or digital) once the electron multipactor current it causes is specified. Examples using planar and coaxial transmission lines are given on a simple dynamical model of the multipactor current. Single and multitone signals are treated, with some results presented in the In-phase and Quadrature plots.

Pushing the limits of General Relativity beyond the Big Bang singularity

AbstractThe predictions of General Relativity suggest a universe in which, as we follow time backward, the hotter and the more dense it was, and the more rapidly it was expanding and that, around 13.7 billion years ago, at the extreme gravitational regime of its evolutionary process, the density, temperature, and expansion rate of the universe would start off as infinite. The General Relativity prediction of a singularity in the early universe would impose a limitation to our understanding of the cosmos and gravity, implying loss of logic and of formal consistency and predictability, making it impossible to impose initial conditions. These extreme conditions of the initial state of the universe are very far from our experimental possibilities, and presently, theoretical models allow only speculations about the avoidance of physical singularities or about the physical conditions that allow circumvent this drastic consequence of General Relativity. Speculations aside, in this study, we follow an analytical line in which we apply the tools of singular semi‐Riemannian geometry to push the limits of General Relativity beyond the Big Bang singularity.