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Spectrochimica Acta
Pergamon Press
Spectrochimica Acta

Pergamon Press

0584-8547

Spectrochimica Acta/Journal Spectrochimica Acta
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    In-run measuring (HfO)-Hf-177-O-16/Hf-177 as a routine technique for in-situ Hf isotopic compositions analysis in zirconium-bearing minerals by laser ablation MC-ICP-MS

    Huang, ChaoYang, YuehengWang, HaoXie, Liewen...
    9页
    查看更多>>摘要：Problems with REE oxide interferences during in-situ Hf isotope analysis in zirconium-bearing minerals can give rise to inaccuracies in the obtained dataset. In this study, we present an in-run 177Hf16O/177Hf measurement protocol pertaining to in-situ Hf isotope analysis by laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) as a routine method, allowing for a robust real-time method of monitoring the oxide formation rates and offering a method to monitor REE oxide interferences (e.g., Gd and Dy). For this purpose, we set up a static data collection mode to measure Hf isotopes and 177Hf16O signals concurrently in-run. By analyzing zirconium-bearing minerals characterized with a broad range of Dy/Hf and Gd/Hf ratios (e.g., zircon: typically, 0.0001-0.022 for Dy/Hf and 0.00002-0.013 for Gd/Hf; zirconolite: typically, >0.2 for Dy/Hf and > 0.4 for Gd/Hf; eudialyte: typically, >0.1 for Dy/Hf and > 0.1 for Gd/Hf), influences of oxide formation rate on 176Hf/177Hf ratios are investigated via the present in-run method. The level of oxide formation during the analysis is found to impact the measurement accuracy, especially for samples with higher REE/Hf ratios. Therefore, it is imperative that oxide ratios should be routinely monitored for daily in-situ Hf isotope analysis along with oxide formation rates. In addition, based on results of the present work, a higher REE/Hf zircon, like SA02 zircon, is strongly recommended as the primary refence material for routine in-situ analysis of Hf isotopic compositions in zircons to carefully test the accuracy of analysis for zircons.
      原文链接:
    • NSTL
    • Elsevier

    Using of electrothermal vaporization for direct analysis of zinc solid samples by two-jet arc plasma optical emission spectrometry

    Kuptsov, A. V.Medvedev, N. S.Polyakova, E. V.Saprykin, A. I....
    6页
    查看更多>>摘要：The technique of the direct analysis of zinc solid samples by two-jet arc plasma optical emission spectrometry (TJP-OES) with electrothermal vaporization (ETV) of samples is developed. Vaporization of sample matrix (zinc) and analytes from graphite tube during different temperature programs is investigated. The matrix influences from zinc on the signals of analytes are studied in detail. It has been shown that the simultaneous vaporization of analytes and sample matrix makes it possible to determine the content of the largest number of analytes elements with insignificant matrix effects. The results of optimization of instrumental parameters of TJP-OES analysis are presented. The technique of direct ETV-TJP-OES analysis of zinc provides limits of detection (LODs) of Ag, Al, Au, B, Ba, Be, Ca, Co, Cr, Fe, Ga, Mg, Mn, Ni, Re, Sn and Sr from 0.05 to 100 ng g-1. Due to the high efficiency of ETV for the sample introduction the LODs of most analytes were improved from 2 to 20 times comparing to the TJP-OES with standard sample introduction system.
      原文链接:
    • NSTL
    • Elsevier

    Advances on microLIBS and microXRF mineralogical and elemental quantitative imaging

    Fabre, CecileTrebus, KimberlyTarantola, AlexandreCauzid, Jean...
    13页
    查看更多>>摘要：Mineralogical and petrographic studies require analytical methods capable to underline the repartition of major to trace elements within geological samples. The EPMA (Electron Probe Micro Analyzer) conventional method used for such investigation, but on restrictive zones, is on the verge to be reached by mu LIBS (micro Laser-Induced Breakdown Spectroscopy) and mu XRF (micro X-Ray Fluorescence) techniques allowing the elemental imaging on thin rock sections or even larger samples in only several hours. These spectroscopic methods with extremely fast acquisition speed (similar to 10 ms/pixel) are perfectly adapted to perform multi-elemental imaging of major to trace elements down to the ppm-level. Here, on a mica schist thin section that displays a wide paragenesis of minerals, mu LIBS and mu XRF quantitative elemental mapping are obtained using EPMA spot analyses as internal reference compositions. We exhibit the precision of the mu LIBS and mu XRF quantitative elemental imaging for major and trace elements repartition in an entire thin/thick rock section. According to these oxide weight contents, a rapid mineral classification is obtained, with a good discrimination between minerals even for those with similar compositions (alumino-silicates such as andalusite and kyanite) and within a complex matrix (Fe-oxides, quartz, micas, feldspars...).
      原文链接:
    • NSTL
    • Elsevier

    Collisional radiative model for high-ionization-rate equilibrium argon plasma plume*

    Han, XingWu, PengChen, ZhiyuanQi, Jiayun...
    10页
    查看更多>>摘要：An extensive collisional radiative model for the neutral argon and singly ionized argon plasma is developed to estimate the key properties of the high-ionization-rate equilibrium plasma plume. Major thirty-one argon atomic levels and ninety-five singly ionized argon levels are considered. The processes taken into account are radiative decay, electron impact ionization, excitation and deexcitation between all the levels, fast ion and atom impact excitation, and three body recombination. The model in conjunction with optical emission spectroscopy could be used to evaluate the electron temperature Te, the electron density ne, atom density ng and to investigate the dynamics of excitation population density. The local plasma spectrum in the plume region of an applied-field magnetoplasmadynamic thruster was measured with an optical immersion probe. The fundamental physical processes leading to W-shaped compound light variation in plume zone are explained based on the above plasma parameter distributions. A satisfactory agreement with the results measured by a Langmuir probe verifies the model's applicability to argon plasma plume.
      原文链接:
    • NSTL
    • Elsevier

    Effect of silicon nitride coating thickness on silicon wafer substrates for signal enhancement in laser-induced breakdown spectroscopic analysis of liquids

    Kaplan, DilaraYalcin, Serife H.
    11页
    查看更多>>摘要：It has been shown by previous studies of our group that the use of nitride-coated silicon wafer surfaces as a sample loading substrate in dried-droplet LIBS analysis provided enhancement in plasma emission signal and better detection limits compared to uncoated or oxide-coated silicon wafer surfaces. To further investigate the effect of coating thickness for enhanced sensitivity in dried nano-droplet analysis of liquids, silicon-wafer substrates of different nitride coating thicknesses; 75, 300, 450, and 1000 nm, were comparatively studied. With 75 nm silicon nitride coating, the thin-film effect due to the anti-reflective behavior of the silicon nitride film is observed, and plasma emission signal is enhanced up to three times compared to 300 nm coated substrates. With coating thicknesses of 450 nm and 1000 nm, on the other hand, thermophysical and mechanical properties of the silicon nitride material, like thermal conductivity and hardness, become more dominant factors, leading to higher emission signals for all the elements studied. With 1000 nm coating thickness, enhancement factors of 4.8, 6.4, and 3.7 were obtained for the elements of Pb, Cu, and Cr, respectively. Optimization of the experimental LIBS parameters was conducted, calibration curves were constructed, and analytical figures of merits were determined. Sub-picogram amounts absolute detection limits; 0.7 pg Pb, 0.6 pg Cr, and 0.4 pg Cu, in 500 nanoliter droplets were obtained from the slopes of the calibration curves. The nitride-coated substrates' analytical performance was tested using certified reference solutions, standard water, and real water samples. The materials and the methodology developed can be used for waste-water monitoring of environmental samples by LIBS.
      原文链接:
    • NSTL
    • Elsevier

    Determination of uranium and plutonium in mixed oxide samples by X-ray methods and their comparison with potentiometry

    Bootharajan, M.Kumar, G. V. S. AshokSreenivasulu, B.Senthilvadivu, R....
    6页
    查看更多>>摘要：Uranium and plutonium in nuclear fuels are generally determined by conventional potentiometric methods which generates large quantities of radioactive waste. In the present study, K-edge densitometry (KED) and Energy dispersive X-ray fluorescence (EDXRF) have been examined for the determination of uranium and plutonium in solutions as an alternative to potentiometric methods. In the present study, uranium plutonium mixed oxide (MOX) pellets were dissolved in nitric acid medium containing small quantities of HF. Uranium and plutonium in MOX solutions were determined by KED and EDXRF methods and the results are compared with the one obtained by conventional potentiometric methods. The relative standard deviation (RSD) of the analytical results for U and Pu using KED were found to be better than & PLUSMN;1% and & PLUSMN; 0.9% respectively. Similarly, RSD for U and Pu by EDXRF were found to be better than & PLUSMN;1.6% and & PLUSMN; 0.8%, respectively. The absolute difference between KED and EDXRF with respect to potentiometric data for uranium and plutonium were calculated and it was found to be marginal indicating that KED and EDXRF methods can be employed for the routine analysis of U and Pu in solutions. X-ray methods employed in the present study are non-consumptive, direct and offer precise determination of U and Pu and generate no waste.
      原文链接:
    • NSTL
    • Elsevier

    Laser-induced plume fluorescence for ultrasensitive and simultaneous multianalyte analysis - A review

    Cheung, Nai-Ho
    17页
    查看更多>>摘要：This is a comprehensive review of the research work on ultraviolet laser-induced fluorescence of dense plumes for ultra-trace material analysis. It covers the studies published between 2005 and 2021. By using this technique, numerous atomic and molecular analytes can be induced to fluoresce simultaneously at a single excitation wavelength, provided that two criteria are met. First, that the excitation wavelength is in the vacuum ultraviolet. Second, that the analytes are imbedded in dense plumes, such as those produced by pulsed laser ablation. The review is divided into three parts. In part I, the underlying mechanism is explained conceptually and corroborated experimentally. In part II, the analytical applications to ceramics, metals, plastics, and their composites are summarized. Detection limits in the ng/g range and mass limits of atto moles were demonstrated. Several real-world problems, including the analysis of paints for trace lead, the non-destructive sorting of potteries, the forensic analysis of written and printed inks, and the analysis of ingestible lead colloids in drinking water are discussed. In part III, highly effective denoising algorithms based on the linear normalizability of the fluorescence signal are described. They facilitated the soft and robust classifications of antiques and artworks. The review concludes with suggestions for further studies.
      原文链接:
    • NSTL
    • Elsevier

    Increasing resolution in chemical mapping of geomaterials: From X-ray fluorescence to laser-induced breakdown spectroscopy

    Raneri, SimonaBotto, AsiaCampanella, BeatriceMomcilovic, Milos...
    10页
    查看更多>>摘要：Laser-Induced Breakdown Spectroscopy (LIBS) micro-mapping is an important analytical tool for the study of geomaterials. In this work, this technique was applied, for the first time, to the analysis of alkali-activated materials and geopolymers, as well as rocks, mortars and bricks. The results obtained were compared with the ones obtained using Energy-Dispersive X-Ray Fluorescence (ED-XRF) macro-mapping and the advantages of the LIBS approach (speed, lateral and in-depth resolution, capability of light elements analysis) were highlighted.The issues associated with the quantitative determination of the samples' composition from the analysis of the LIBS spectra were also briefly discussed.
      原文链接:
    • NSTL
    • Elsevier

    Comparative study on quantitative carbon content mapping in archaeological ferrous metals with laser-induced plasma spectroscopy (LIBS) and nuclear reaction analysis (NRA) for 3D representation by LIBS

    Bai, XueshiCalligaro, ThomasPichon, LaurentMoignard, Brice...
    8页
    查看更多>>摘要：The carbon content distribution of ferrous archaeological artefacts in a quantitative way allows us to understand the nature of the materials. Our previous works have ever proved that the use of laser-induced breakdown spectroscopy (LIBS) could be an efficient method to solve problems of in situ analysis and offer a high spatial resolution. To assess the ability of this quantification in an absolute way the carbon quantification by LIBS is compared in this paper with the nuclear reaction analysis (NRA), one of the ion beam analysis (IBA) techniques generated by a deuterium ion beam. The IBA analysis has specific advantages, especially in terms of precision and non-destructiveness. A validation study is also presented on quantitative carbon content mapping in archaeological ferrous metals with LIBS and deuterium ion beam analysis. The application of LIBS quantitative mapping on different structures of archaeological pieces shows that the carbon content distribution can be well determined, demonstrating the 2D mapping capabilities of the laser techniques. With the help of LIBS stratigraphic analysis, a 3D deeper insight on microscale features presents a heterogeneity, induced better understanding of material organization at the microscale.
      原文链接:
    • NSTL
    • Elsevier

    Diagnostic study of interface materials of co-deposition simulating impurity relevant to international thermonuclear experimental reactor by using calibration-free laser-induced breakdown spectroscopy

    Imran, MuhammadHu, Zhen-huaDing, FangDing, Hongbin...
    9页
    查看更多>>摘要：The quantitative analysis and depth profiling of a co-deposition simulating the impurity of the international thermonuclear experimental reactor (ITER) has been performed by using laser-induced breakdown spectroscopy (LIBS). In the depth profile analysis of a co-deposition of Al/W/Mo, the materials were resolved across the interfaces of layers using four different values of laser fluence. The variation in concentration of materials across the interfaces was observed for seven laser shots with each fluence value. The calibration-free LIBS analysis provided elemental abundance across the interfaces. The decay and rise occurred slowly in the evolution of the elemental percentage of the two materials across the interfaces as material ablated by the laser pulse having a Gaussian beam profile. The quantitative and depth profiling results are fully agreed in material analysis across the interfaces of layers. The results obtained through depth profiling and quantitative analysis of co-deposition evidenced that LIBS is a promising technique for the diagnosis of unknown materials of impurity deposition in the fusion devices.
      原文链接:
    • NSTL
    • Elsevier