首页期刊导航|Spectrochimica Acta
期刊信息/Journal information
Spectrochimica Acta
Pergamon Press
Spectrochimica Acta

Pergamon Press

0584-8547

Spectrochimica Acta/Journal Spectrochimica Acta
正式出版
收录年代

    Energy dispersive X-ray fluorescence determination of uranium in different uranates using Rh Kα scattered peaks for matrix correction

    Kumar S.S.Dhara S.
    5页
    查看更多>>摘要：? 2022 Elsevier B.V.Determination of uranium in different matrices and compounds is required for compositional analysis and material characterization of uranium based materials. In the present work, we have explored the possibility of utilising Rh Kα scattered peaks: Compton and Rayleigh, for minimizing the effect of matrix and determining uranium in different matrices using Energy Dispersive X-Ray Fluorescence (EDXRF) spectrometry. The method was applied for determination of uranium in presence of Na, Zn, Rb, Bi and Th in solid samples presented in the form of compounds and mixtures. Different calibration plots were made for U in different matrices against the intensity of the scattered peaks. Different procedures of calibration were studied using both uranium Lα and Lβ as analytical lines. Sample specimens were presented in the form of fused bead as well as pressed pellets. The advantage of this method is that there is no need to add any standard in the samples. The analytical results of all the studies showed an average deviation of 3% between the EDXRF determined and the expected uranium concentrations and a RSD (Relative Standard Deviation) of 4% (1 s, n = 3).
      原文链接:
    • NSTL
    • Elsevier

    Laser induced breakdown spectroscopy with annular plasmas in vacuo: Stagnation and limits of detection

    Delaney B.Hayden P.Kennedy E.T.Costello J.T....
    7页
    查看更多>>摘要：? 2022 The AuthorsThe purpose of this study is to investigate the possible improvement of the limit of detection of laser induced breakdown spectroscopy using the stagnation layer formed at the centre of an annular plasma. An axicon was used to form an annular plasma on various certified reference targets, the spectra from which were used to construct calibration curves and extract the limit of detection for the system. Comparisons were drawn between the limit of detection for the annular case, dual colliding plasma case and a single plasma case. Clear signal enhancement for certain spectral lines can be seen in the presented spectra. The limits of detection between systems are similar, but the stagnation layer produced from an annular plasma produces the lowest value, for the lowest laser power density and hence least target damage. The signal enhancement and improved limit of detection, at lower power densities, from a stagnation layer at the centre of an annular plasma is a promising result.
      原文链接:
    • NSTL
    • Elsevier

    Solid phase extraction materials as a key for improving the accuracy of silver nanoparticle characterization with single-particle inductively coupled plasma mass spectrometry in natural waters through dissolved silver removal

    Kinnunen V.Peramaki S.Matilainen R.
    11页
    查看更多>>摘要：? 2022 The AuthorsThe accurate characterization of silver nanoparticles (Ag NPs) in environmental samples is crucial for understanding the potential impact of these materials on the environment and human health. Single-particle inductively coupled plasma mass spectrometry (spICP-MS) is one of the few techniques available for quantifying NPs at environmentally relevant concentrations. However, the spICP-MS detection of Ag NPs can be interfered with coexisting dissolved analyte causing high background signals, which mask NP signals leading to a significant bias in NP characterization. In this paper, a simple sample pre-treatment procedure for efficient removal of dissolved silver in natural waters is proposed using solid phase extraction (SPE) materials, allowing more accurate characterization of NPs in environmental water matrices. The applicability of eight commercially available SPE materials was evaluated based on their effects on sample Ag NP properties and dissolved silver extraction efficiency in environmental waters, which were shown to depend on sample matrix. The SPE materials found most efficient in dissolved silver extraction were further studied for improving the characterization of 30 nm Ag NPs in colorless and dark-colored waters. Whereas dissolved silver concentrations of ≤1 μg kg?1 were shown to lead to a significant bias in NP characterization (up to +58% increase in NP size and ? 90% decrease in particle concentration), pre-treatment of the samples with SPE materials ‘SiliaMetS Thiol’ and ‘Purolite C115HMR’ minimized the effect of dissolved silver interference. As a result, highly more accurate NP sizing (28 ± 2 nm) and relatively stable particle concentration was obtained for 30 nm Ag NPs in environmental waters.
      原文链接:
    • NSTL
    • Elsevier

    Quantitative verification of 1:35 diluted fused glass disks with 10 mg sample sizes for the wavelength-dispersive X-ray fluorescence analysis of the whole-rock major elements of precious geological specimens

    Sun J.-F.Xue D.-S.Tian H.-C.Zhang D.-P....
    8页
    查看更多>>摘要：? 2022 Elsevier B.V.Herein, an improved wavelength-dispersive X-ray fluorescence (WD-XRF) analytical technique for determining the major elements (including SiO2, TiO2, Al2O3, TFe2O3, MnO, MgO, CaO, Na2O, K2O, and P2O5) in precious geological samples, particularly extraterrestrial basaltic rock samples, was developed. For WD-XRF analysis, undersized (approximately 11 mm in diameter) glass disks were prepared by fusing 10 mg of a powdered sample with 350 mg of lithium borate flux at a sample-to-flux ratio of 1:35. Specialized Pt[sbnd]Au crucibles and molds were crafted for glass disk preparation to facilitate automatic fluxer mounting. This procedure enabled the automatic preparation of undersized glass disks, with repeatability between sample batches. Calibration curves were constructed for 30 certified reference materials (CRMs), including felsic, intermediate, mafic, and ultramafic igneous rocks. Regular-sized CRM disks with large sample sizes were prepared at the same sample-to-flux ratio as the test samples to avoid issues caused by CRM heterogeneity. The influence of various factors, including glass disk thickness and homogeneity, releasing agent amount, and interference between lines (Br Lα with Al Kα, Rh Lγ2 and Rh Lγ3 with K Kα, and K Kβ with Ca Kα), on analytical accuracy was investigated. Two homogeneous synthetic reference glass samples (ARM-2 and ARM-3) were pulverized and used to verify the analytical results for small samples using the WD-XRF method, which could eliminate the uncertainty caused by sample homogeneity. Subsequently, three CRMs (JB-1b, JA-3, and JR-1) were used to validate the accuracy and precision of the method. Finally, two lunar meteorite samples (NWA4898 and NWA4734) were assayed by the proposed method, and comparison with inductively coupled plasma optical emission spectroscopy results confirmed the reliability of the method. The proposed small sample protocol, which involves the destructive pretreatment of precious and limited extraterrestrial basaltic samples, has great application potential for precious samples such as lunar soil samples.
      原文链接:
    • NSTL
    • Elsevier

    Photoionization cross-section measurements from the 6s5d 1D2 excited state of atomic ytterbium

    Shafique B.Ali R.Rafique M.Haq S.U....
    6页
    查看更多>>摘要：? 2022 Elsevier B.V.We present new experimental measurements on the photoionization cross-sections from the 6s5d 1D2 excited state of ytterbium using a heat pipe-cum-linear thermionic diode ion detector, working in the space-charge limited mode to generate ytterbium vapor. A Nd:YAG laser pumped narrow bandwidth (~ 0.2 cm-1) Hanna-type dye laser, charged with LDS-698 dye and tuned at 722.6 nm, was used to excite atoms via the 6s2 1S0 → 6s5d 1D2 two-photon transition from the ground state. The excited state population was then promoted to the ionization threshold at 439.2 nm ionizing laser wavelength and above the ionization threshold at 435 nm, 355 nm, and 266 nm laser wavelengths. The photoionization cross-sections at each of these wavelengths have been determined using the saturation technique. At the first ionization threshold, the photoionization cross-section from the 6s5d 1D2 excited state is extracted as 40.5 ± 6.2 Mb, whereas at higher energies in the continuum, the cross-section decreases up to 6.4 Mb at 266 nm, which corresponds to 1.84 eV excess energy.
      原文链接:
    • NSTL
    • Elsevier

    Laser-induced breakdown spectroscopy signal enhancement effect for argon caused by the presence of gold nanoparticles

    Geretovszky Z.Palasti D.J.Galbacs G.Villy L.P....
    9页
    查看更多>>摘要：? 2022 The AuthorsThe effect of the presence of nanoparticles (NPs) on the laser induced breakdown spectroscopy (LIBS) signal of argon gas was studied experimentally. 10–20 nm diameter gold NPs, produced by a spark discharge nanoparticle generator, were suspended in argon gas. The effect of particle size, number concentration and mass concentration, as well as laser pulse energy on the LIBS argon signal was systematically investigated. It was found that the breakdown threshold of the gas decreases considerably, facilitating the detection of Ar emission at such laser fluences, which do not allow plasma formation without the presence of the NPs. Our observations persist even at aerosol mass concentrations that are too low to allow the direct detection of nanoparticles. The effect, which is attributed to electron thermo- and field emission induced by the high intensity laser pulse, shows an asymptotically increasing magnitude with the aerosol mass concentration. The signal enhancement was found to be 102–104 and the effect is suggested to be useful in trace gas analysis or for the indirect detection of NPs. The achievable indirect aerosol mass concentration detection limit was estimated to be in the parts per trillion regime (as low as 50 ng·m?3), which is comparable to the best literature values reported for direct analysis.
      原文链接:
    • NSTL
    • Elsevier

    Gas temperature and air fraction diagnosis of helium cold atmospheric plasmas by means of atomic emission lines

    Garcia M.C.Yubero C.Rodero A.
    9页
    查看更多>>摘要：? 2022 The AuthorsIn this work, we present a new method allowing the determination of both the gas temperature and the air fraction in non-thermal atmospheric helium plasmas. This new UV-Atomic Emission Spectroscopy technique based on the measurement of the collisional broadening of the He I 667.82 nm and He I 728.13 nm emission lines is a particularly sensible method under low gas temperature conditions; hence it is particularly suitable for the diagnosis of cold helium atmospheric plasmas of biomedical use. To quantify the unknown amount of air entering these plasma jets is key to understanding the chemistry in them and the basis of their clinical and biological action, as it determines the amount of reactive oxygen and nitrogen they generate. The method has been applied to diagnose microwave helium plasmas generated inside three different reactors, thus in environments with different air contents.
      原文链接:
    • NSTL
    • Elsevier

    Matrix effect correction method based on the main spectral parameters for rock samples in an in situ energy dispersive X-ray fluorescence analysis

    Wang M.Gu Y.Lu H.Ge L....
    7页
    查看更多>>摘要：? 2022 Elsevier B.V.Due to the differences in the matrix effects between different types of rocks, the target element contents in different rocks cannot be accurately determined by in situ X-ray fluorescence (XRF) analyses with the same parameters of the quantification procedure. We investigated the matrix effect correction methods of an in situ energy dispersive X-ray fluorescence (EDXRF) analysis for different matrix rock samples using Monte Carlo simulations (17 types of rock samples) and experimental verification (10 types of rock samples), in which both Cu and Zn were selected as target elements. The following conclusions were drawn. The matrix effect classification of the rock samples was not completely controlled by the detectable elemental composition or petrographic classification. According to the correlation between the spectral parameters and the characteristic X-ray intensity of the target elements, the matrix effect classification of rock samples could be more detailed. For rock samples in the same rock classification set and with the same target element content, the target element Kα X-ray intensity could be accurately described by the main spectral parameters, which include the scattering background at an energy interval of 4–19 keV, the Compton peak and the Rayleigh peak. Then, a matrix effect correction method was established, which allowed for the fast measurement of the target element contents of different rock samples by following the same parameters of the quantification procedure in the in situ EDXRF analysis. Simultaneously, six types of rock samples containing 3% Zn were selected as the validation set, and the relative errors of the target element content measurements in different rock samples were all less than 6% using the same parameters of the quantification procedure.
      原文链接:
    • NSTL
    • Elsevier

    Spatially resolved EDS, XRF and LIBS measurements of the chemical composition of duplex stainless steel welds: A comparison of methods

    Griesche A.Kannengiesser T.Quackatz L.
    8页
    查看更多>>摘要：? 2022 Elsevier B.V.Duplex steels (DSS) are used in all industries where corrosion problems play a major role. Examples include the chemical industry, the food industry and shipping industries. DSS have a balanced phase ratio of ferrite (α) and austenite (γ). Unlike single-phase stainless steels, DSS combine the advantages of these and can therefore fit many industry requirements, such as weight saving or high mechanical strength. When these steels are welded, alloying elements can burn off and condense as thin layers on cold surface regions. This loss of chemical elements can lead to changes in the microstructure. With the help of Laser-Induced Breakdown Spectroscopy (LIBS), chemical element distributions were visualized. The results were compared with those of conventional measurement methods, such as energy dispersive X-ray analysis (EDS) and X-ray fluorescence analysis (XRF), and the results from LIBS could be validated. LIBS is suitable as a fast, straightforward measurement method for producing line scans along the weld seam and provides spatially resolved information on accumulation phenomena of burned off alloying elements. LIBS is very well suited for the detection of sub-surface elements due to the exclusively superficial ablation of the material. In addition, the measurement method has been calibrated so that quantitative statements about element concentrations can also be made.
      原文链接:
    • NSTL
    • Elsevier

    Elsevier/spectrochimica acta atomic spectroscopy award 2021

    De Giacomo A.de Loos-Vollebregt M.
    1页
      原文链接:
    • NSTL
    • Elsevier