Journal of Analytical Atomic Spectrometry最新文献

Microanalysis of silver isotopes in gold (Au) by laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) has been an important tool to reveal the source and enrichment processes of Au. However, preparing an Au-matrix reference material with homogeneous Ag isotope compositions at a micron scale remains a major challenge. This study presents a novel method to synthesize a homogeneous gold reference material, named NWU-Au, via flux-free fusion. Moreover, a natural gold reference material, DD440, is prepared for in situ Ag isotope measurement by LA-MC-ICP-MS. Elemental mapping obtained by electron probe microanalysis indicates that both gold reference materials have homogeneous Au and Ag contents, while LA-MC-ICP-MS measurements further demonstrate their homogeneous distribution of Ag isotopes. The intermediate precision of δ¹⁰⁹Ag was better than 0.06‰ (2s) for NWU-Au and DD440, which were suitable to serve as matrix-matched calibration materials. Silver isotopic compositions of six gold samples were also determined using LA-MC-ICP-MS with matrix-matched calibration, and the δ¹⁰⁹Ag_NIST978a values were consistent with those obtained by SN-MC-ICP-MS, suggesting that LA-MC-ICP-MS can accurately determine Ag isotopic ratios in gold samples. Thus, this synthesis method, along with an analytical approach, enables potential determination of spatially resolved Ag isotope compositions at the mineral scale to reveal the source and enrichment processes of Au in the Au deposit.

Although a longer integration time can enhance the spectral intensity, it also obscures more information regarding plasma evolution. In this study, laser-induced plasma (LIP) is detected simultaneously by using both long-integration-time and short-integration-time spectrometers via a Y-shaped fiber, and the effect of integration time on the repeatability and the inversion of plasma parameters for laser-induced breakdown spectroscopy (LIBS) spectra is investigated. The results reveal that (1) the radiation decay rate at the same wavelength varies among different LIPs, leading to increased differences in line intensities with longer integration times. However shorter integration times theoretically improve repeatability, in fact, shorter integration times tend to improve the repeatability of strong emission lines, but reduce the repeatability of weak emission lines by reducing their signal-to-background ratios (SBRs) and signal-to-noise ratios (SNRs). (2) The radiation decay rates at different wavelengths also vary within the same plasma, causing further increases in spectral line intensity differences with longer integration times. This results in greater vertical dispersion of data points in Boltzmann or Saha–Boltzmann plots, leading to underestimated plasma temperatures. (3) Longer integration times may also lead to underestimation of electron densities derived from the Stark broadening method. This study provides significant guidance for optimizing LIBS integration parameters, improving repeatability and advancing plasma spectral diagnostics.

The TwinMic beamline at Elettra synchrotron has been active in the past few decades in research fields such as medicine, pharmacology, toxicology and environmental science, offering combined scanning transmission X-ray and X-ray fluorescence microscopy. Here, we present the recent advances of TwinMic in performing micro X-ray absorption near edge spectroscopy on biological specimens.

Remote laser-induced breakdown spectroscopy (LIBS) has attracted significant research attention in the field of metallurgy due to its ability to enable rapid and remote elemental analysis. However, maintaining the stability of remote analysis and achieving reliable results across varying distances remain challenging. Here, an innovative portable LIBS instrument has been developed, with a modular design to reduce complexity and increase usability. The portable remote LIBS was employed to simultaneously detect multiple elements in steel samples at different standoff distances. A multi-distance shared calibration curve was developed to provide a simple and accurate quantitative method for different standoff distances. This method allows quantitative analysis at different standoff distances with only one calibration curve. The coefficient of determination of the multi-distance shared calibration curve is 0.9641 within the standoff distance range of 2000 mm to 2400 mm, with the lowest mean relative error being 0.67% for Mn quantification at the 2000 mm distance. In field environments, the relative standard deviation of Mn element spectral line intensity decreased from 9.89% to 7.48% and that of Cr element spectral line intensity dropped from 10.34% to 8.25%. This method has shown potential usefulness as analytical quality control for remote LIBS instruments. It may be further optimized for use in production processes requiring speed and stability analysis.

In this work, a novel method for the highly sensitive detection of trace tellurium (Te) was developed based on photochemical vapor generation (PVG) coupled with inductively coupled plasma mass spectrometry (ICP-MS). Effects of antimony (Sb) and ferric ions (Fe) on the PVG of Te were reported for the first time. In a medium containing 2% (v/v) acetic acid (AA), 5.0 mg L⁻¹ of Sb(III), and 15.0 mg L⁻¹ of Fe(III), the conversion efficiency for both Te(IV) and Te(VI) was found to be 94% ± 3% upon 90 s of UV irradiation using a thin-film flow-through mercury lamp. The limit of detection (LOD, 3σ, n = 11) was 0.4 ng L⁻¹ for both Te(IV) and Te(VI), which was enhanced about 40 times for Te compared with that obtained using commercial pneumatic nebulization (PN) with ICP-MS. Good precision was achieved, with relative standard deviations (RSDs) of 2.1% and 2.5% for 1.0 µg L⁻¹ Te(IV) and Te(VI) standard solutions (n = 7), respectively. The method was successfully applied to determine trace inorganic Te in three environmental water samples with satisfactory results. Compared with the previous reported PVG systems for Te, the use of organic acids was significantly reduced by more than 10-fold while maintaining high sensitivity. The mechanism of PVG was investigated, and it was found that, in addition to volatile Te, volatile Sb and Sb nanoparticles were generated in this system. This study provides a new perspective for the direct analysis of the total amount of elements in environmental samples and contributes to understanding the interactions between Te, Sb, and Fe during photochemical processes.

The (U–Th)/He dating technique has been widely applied for constraining shallow crustal geological processes, with apatite being the most commonly used mineral due to its low closure temperature and broad occurrence. Currently available (U–Th)/He reference materials, including Durango, Fish Canyon Tuff (FCT), Limberg t3 Tuff (LT3T), and MK-1, are relatively young (<40 Ma). This highlights the need for a new, homogeneous, and older reference. In this study, we characterize a new apatite sample, OLG, obtained from a mineral dealer and sourced from the Otter Lake area in the Grenville Province, Canada. Single-grain (U–Th)/He dating yields highly reproducible ages of 210.2 ± 1.4 Ma (2σ), significantly older than those of existing reference materials. BSE imaging, EPMA, and LA-ICP-MS analyses confirm its major-element homogeneity and relatively uniform trace-element distribution, although minor inclusions could be present. OLG shows strong U, Th, and He signals, with an average U concentration of ∼112.2 ppm, Th concentration of ∼923.7 ppm, and a Th/U ratio of ∼8.2. Its older age, high U and Th concentrations, and excellent compositional homogeneity indicate that OLG could serve as a robust new reference material for high-precision (U–Th)/He thermochronology.

Sn is the main isobaric interferent for Cd isotopic composition determination. To eliminate Sn, two-step separation methods using an anion resin combined with commercially available TRU and UTEVA extraction resins are usually required for high-precision Cd isotope ratio measurements. First, the AG1-X8 or AGMP-1M anion resin is utilized to eliminate the matrix and most Sn isobaric interferences. Subsequently, extraction resins are employed to eliminate residual Sn. However, these extraction resins are costly. In this study, we present a new approach using the commercially available TBP (tri-n-butyl phosphate) extraction resin as an alternative. The TBP extraction resin is highly cost-effective (∼5% of the cost of TRU or UTEVA extraction resins) and shows excellent performance in Sn removal. Our two-step procedure achieves high recovery (>99% Cd) with a low procedural blank (<30 pg), enabling the efficient isolation of Sn and Cd from bulk rock solutions. The validity of the proposed method was confirmed by analyzing six geological reference materials, including GSD-11 with a very high Sn/Cd ratio, yielding results in good agreement with the published values.

The lack of suitable calibration standards is a persistent bottleneck for quantitative bioimaging by LA-ICP-MS. Widespread use of in-house calibration approaches has led to a lack of harmonisation limiting the potential of LA-ICP-MS in clinical or biomedical fields. This work addresses this challenge by utilising automation via a bioprinting approach to produce re-usable gelatin-droplet standards, doped with multiple elements for both instrument tuning and quantitative analysis. The resulting standards were systematically characterized in terms of thickness, elemental homogeneity, and long-term stability. Droplets were doped with Ti, Ce, Au, Th and U (used for instrument tuning) as well as increasing concentrations of lanthanides such as Gd and Yb (typically used in bio-clinical applications). Variation of thickness (measured by ellipsometry) between droplets, after printing and dehydration, was 5% (RSD, n = 12). Intra- and inter-droplet elemental homogeneity were less than 6% (RSD, n = 10) and 8% (RSD, n = 9), respectively for all elements. Due to the reproducibility of both physical characteristics (thickness and size) and elemental distribution, there is no need of ablating the entire droplet. Instead, ablation of an area as small as 1 line across a droplet produced elemental data which is representative of the entire droplet. This feature enables the same droplet to be used across multiple batches or multiple times within a batch, the latter for quality control purposes. Data from long-term stability and shipping tests highlight the usability of these standards and a potential route towards harmonisation.

Technetium (Tc) is a very important element that is encountered in many aspects, from its presence in radioactive waste and its potential environmental impact to its use as a medical radioisotope. Its detection and quantification in liquid samples is traditionally cumbersome, involving detailed sample preparation and analysis by mass spectrometry or scintillation. This article demonstrates the first comprehensive emission spectral analysis of Tc from a liquid sample by immobilization in a polymer and analysis by laser-induced breakdown spectroscopy (LIBS). A survey of LIBS spectra was completed to identify the strongest analytical lines for quantification of trace Tc in the presence of Mo. The quantification of Tc in a Mo-containing matrix was selected because Tc radioisotopes are the daughter products of Mo isotope decay. The first reported calibration curves by LIBS are provided with limits of detection and quantification down to 0.710 µg mL⁻¹ and 1.39 µg mL⁻¹, respectively. Ultimately, this study demonstrated the feasibility of trace Tc quantification using LIBS and will serve as a reference for future research related to monitoring this radioactive species.

The study presents the analytical characterization of a cost-effective green and white method for the simultaneous determination of Cd, Pb, Zn, Cu, Hg, Se, and As in food using sample dissolution assisted by oxygen flask combustion and simultaneous detection by small-sized electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometry (OFC-SSETV-µCCP-OES). Attractiveness, effectiveness and cost-efficiency of the novel method were demonstrated through the greenness and whiteness degrees evaluated using the AGREEprep software and RGB 12 algorithm, compared to traditional high-pressure microwave-assisted wet digestion and determination by inductively coupled plasma optical emission spectrometry (HP-MAWD-ICP-OES), graphite furnace atomic absorption spectrometry and thermal desorption atomic absorption spectrometry methods. Signal integration over 5 pixels along the spectral line profile provided an improvement of 2–3 fold of the limits of detection in the range of 0.01 mg kg⁻¹ (Hg, Cd, Zn) to 1.20 mg kg⁻¹ (Se), compared to the measured signal corresponding to the pixel of the emission line maximum. Validation by analysis of certified reference materials proved that the method is not affected by the non-spectral matrix effects, with recoveries and extended uncertainties in the range of 90–113% and 9–25% (k = 2), respectively. Tukey's statistical test (p < 0.05 statistical significance) and z scores revealed no bias between the results obtained by (OFC)-SSETV-µCCP-OES, with both external calibration and the standard addition method, and those obtained by (HP-MAWD)-ICP-OES with external calibration. The applicability of the method was demonstrated through the analysis of fish tissue, mushroom, and dietary supplement samples, with precision ranging from 4.9% to 14.5%. The (OFC)-SSETV-µCCP-OES method presented a greenness score of 77%, evaluated by the AGREEprep metric, while the redness, greenness, blueness and whiteness scores, evaluated by the RGB 12 algorithm, were 86%, 94%, 98% and 93%. The scores are related to the combination of representative features of sample preparation by OFC, namely virtually energy-free processing, reduced reagents consumption and generated waste, along with the potential of simple and cost-effective miniaturized instrumentation for the simultaneous determination of trace elements in a low power (15 W) and low Ar consumption (150 mL min⁻¹) microplasma source, which are essential for greater chemical sustainability in analytical procedures compared to conventional methods.