Journal of Analytical Atomic Spectrometry最新文献

Trace metal elements present in black matter coatings and airborne dust particles trapped by Egyptian mummies were studied by combining µ-PIXE and µ-IBIL spectroscopy and mapping. Among the samples from 16 mummies that were analyzed, a detailed study was carried out on fragments of strips and black matter detached from the enigmatic human mummy preserved in the Musée de Boulogne-sur-Mer, France. Quantification of V and Ni showed that the mummy's bitumen comes from an unknown source, different from the Dead Sea which was the main source of bitumen in the black matter of the other studied mummies. Abundant microparticles of Egyptian blue pigment and of airborne aluminosilicate and carbonate particles trapped on both sides of the samples were detected by µ-PIXE and µ-IBIL, with more aluminosilicates on the inner side of strips, facing the mummy, and more carbonates on the outer faces, facing outward. The nature and distribution of dust particles suggested that the mummy was exposed to at least two dust events: one event in South Egypt during preparation of the mummy, and the other in Northern Egypt after excavation of the mummy. The abundance of mercury indicates that the mummy had undergone, in the first third of the 19th century, undocumented treatments with mercury salts to protect the mummy against insects and fungi.

This paper describes a new methodology based on a time-dependent hydride correction for measuring the isotopic composition of micrometer sized plutonium bearing particles using large geometry secondary ion mass spectrometry. This methodology allows the mitigation of the effect of the hydride interferences on ²³⁶U, ²³⁹Pu and ²⁴⁰Pu on weapon grade plutonium particles, which contain a low amount of the ²⁴⁰Pu isotope, and on MOX particles, which contain a low amount of plutonium at the weight% level. We successfully applied it on six different samples and demonstrated that the deviations from the reference values of the ²⁴⁰Pu/²³⁹Pu isotopic ratios were reduced from +4.6% to +0.24% for the MP2 sample (weapon grade Pu) and from −7% to +0.75% for the UKMOX-100 sample (MOX). We also demonstrated the capabilities for simultaneously measuring the uranium and plutonium isotopic compositions in MOX particles using the dynamic multi-collection mode of LG-SIMS. Moreover, we determined the Pu/U relative sensitivity factor using Pu particles of known ages and applied it to measure the ²³⁹Pu/²³⁸U atomic ratio in MOX particles. At last, the imaging capabilities of the instrument allowed the detection and discrimination of different types of nuclear particles within the same sample, such as U, Pu or MOX particles. This methodology enhances the range of methods applicable to particle analysis in the field of nuclear safeguards and nuclear forensics.

Columbite–tantalite series minerals are widely distributed in granites, pegmatites, carbonatite–alkaline rocks, and peraluminous granites. U–Pb dating of columbite–tantalite minerals can provide robust temporal constraints on petrogenetic and mineralization events. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has become an important analytical technique for columbite–tantalite U–Pb dating, providing high spatial resolution geochronological data through relatively straightforward sample preparation. However, matrix effects between reference materials and unknown samples remain the principal limitation for accurate columbite–tantalite U–Pb dating. The matrix-matched reference materials are crucial for primary calibration or as quality monitoring in LA-ICP-MS columbite–tantalite U–Pb analysis. Although some columbite–tantalite U–Pb dating reference materials have been reported in previous studies, samples containing low amounts of common lead are extremely scarce. Moreover, reference materials covering diverse age ranges are critical for external calibration and quality control, particularly for young materials, given the analytical difficulties in measuring low radiogenic Pb content in young samples by laser ablation. In this study, a Cenozoic columbite–tantalite AFG was investigated as new reference material for LA-ICP-MS columbite–tantalite U–Pb dating. The average U and Pb concentrations in AFG are 1213 ± 112 µg g⁻¹ (2 s) and 3.51 ± 0.45 µg g⁻¹ (2 s), respectively. The isotope dilution thermal ionization mass-spectrometry (ID-TIMS) analysis of AFG yielded a weighted mean ²⁰⁶Pb/²³⁸U ratio of 0.00289 ± 0.000017 (2 s, MSWD = 2.7, n = 5) and a weighted mean ²⁰⁶Pb/²³⁸U age of 18.59 ± 0.06 Ma (2 s, MSWD = 3, n = 5). The results from four independent LA laboratories exhibit excellent homogeneity and yield concordant U–Pb ages. All LA-ICP-MS U–Pb analyses yield a weighted mean ²⁰⁶Pb/²³⁸U age of 18.62 ± 0.05/0.38 Ma (2 s, MSWD = 0.75, n = 288), which is consistent with the ID-TIMS result within analytical uncertainty. We propose AFG columbite–tantalite as a promising new reference material in Cenozoic U–Pb geochronological studies.

Single particle inductively coupled plasma-mass spectrometry (spICP-MS) is a valuable tool to characterise nanoparticles (NPs) regarding their element-specific mass, size and particle number concentration (PNC). However, spICP-MS still suffers from a lack of harmonised and transparent data processing algorithms, resulting in little user-flexibility in adapting parameters, when working with e.g. the manufacturer software. In this study, we present a transparent Python-based algorithm (called ‘Sparta’), validated and critically compared with existing data processing methods (SPCal and an in-house Excel method as well as two commercial instrument software), applied for measurements of ∼30 nm Au, ∼74 nm TiO₂ and ∼50, ∼100 and ∼300 nm SiO₂ NPs, using instruments from two different manufacturers using milli vs. microsecond dwell times. Sparta is capable of correcting baseline drift, determining the particle detection threshold (PDT) via the Poisson and iterative Gaussian method, performing a peak summation necessary for microsecond dwell times, and even extracting specific mass or size distributions from e.g. polydisperse materials via a Gaussian peak-fitting. Although all data processing methods benchmarked sizes and PNCs suit well for Au NPs, results show that millisecond dwell times systematically overestimated sizes for TiO₂ and SiO₂ (from 50–100 nm). For microsecond dwell times, only SiO₂ (50 nm) showed slight overestimation due to the methodological LOD_size of 53.1 nm for our algorithm. Nevertheless, Sparta accurately removes spurious background events of challenging samples such as SiO₂ at larger particle sizes (i.e., 300 nm). Thus, it can be readily applied to other engineered and natural NPs or even for biological cells (single cell ICP-MS) showing its great potential in improving data processing for spICP-MS.

The analysis of double-pulse LIBS plasmas is a promising technique for environmental neutral underwater material exploration. Since the required spectral analysis methods or suitable calibration curves have barely been investigated for deep-sea applications, a method for spectral simulation and evaluation was developed, enabling evaluation of the elemental concentrations even under non-atmospheric conditions. For this, a method for spectral simulation and evaluation was created, containing the simulation of spectra resulting from multi-elemental plasmas, calculation of data sets with spectral characteristics for various plasma pressures, temperatures and elemental concentrations and the estimation of the plasma parameters and the elemental concentrations related to the measured spectra. Then the accuracy was examined depending on different external parameters, such as laser pulse energy and water pressure. Finally, it was shown that a calibration curve routine for copper–zinc alloys could be created with a mean deviation of 3 at% independent of the laser setup. Furthermore, it was shown that this method for spectral simulation and evaluation is suitable to evaluate LIBS spectra for up to 60 MPa hydrostatic water pressure.

Over the past decade, electrochemical in situ imaging and spectral imaging with soft X-ray probes have evolved from a high-risk pioneering challenge to established techniques that now receive substantial beamtime at synchrotron imaging beamlines. Despite a growing body of literature and near-commercial solutions, setting up wet electrochemical cells for these experiments remains challenging and non-routine. Moreover, most published studies revolve around bona fide model materials or environments rather than systems mimicking real in operando conditions. Thus, the concrete impact of these potentially extraordinarily informative approaches remains questionable outside the community of method specialists. In this context, this study aims to lay the foundation for the development of real-life electrocatalysts under electrochemical control. Since these materials are typically fabricated in powder form, their transfer and fixation onto the electrode system of the in situ cell, simultaneously ensuring an appropriate optical density for a high signal-to-noise ratio and maintaining electrochemical activity, remains an open question. The approach is general in nature, but, in this study, we specifically concentrate on α-MnO₂ nanowires, a widely employed oxygen reduction reaction (ORR) electrocatalyst for alkaline metal-air batteries, and describe: (i) the methodology for particle attachment and electrochemical activity assessment; (ii) the fabrication of electrochemical wet cells compatible with these materials; and (iii) the preliminary feasibility of spectral scanning transmission X-ray microscopy (STXM) results at the Mn L-edge.

This study proposed a new loading technique using a tantalum (Ta) gel activator for high-precision Ca isotope (δ^44/40Ca) measurement by double-spike thermal ionization mass spectrometry (DS-TIMS). This method significantly reduces the required sample size of an individual analysis to 25–50 ng and yields a similar level of analytical precision, using double rhenium (Re) filaments, compared with conventional high-precision Ca isotope measurements, which consume microgram-level samples (3–5 µg) using TIMS. We show that the assistance of the Ta gel significantly enhances thermal ionization to a total ion efficiency of up to ∼0.8% compared with the typical rates of ∼0.01–0.05% reported in previous studies, representing an order of magnitude improvement in sensitivity. With a greatly reduced sample size, the potential domain-mixing effect would be avoided, and the mass fractionation is shown to fit well with the exponential law typically observed for TIMS. The δ^44/40Ca values of a suite of standards and geologic reference materials are reported to validate the accuracy and precision of this new method. Repeated measurements of primary standard NIST SRM 915a yielded an external reproducibility better than 0.06‰ (2SD, n = 9, 50 ng sample size). The analyses of USGS standards BHVO-2, BCR-2, and AGV-2 (25–50 ng Ca for each individual measurement) yielded mean δ^44/40Ca values of 0.82 ± 0.09 (2SD, n = 7), 0.79 ± 0.07 (2SD, n = 6), and 0.76 ± 0.05 (2SD, n = 4), respectively. These results suggest the utility of the Ta gel activator in Ca isotope measurements of small samples for potential sample-limited applications in geochemistry and cosmochemistry.

Elemental analysis is crucial for determining the geographical origin of medicinal plants. This study employs laser-induced breakdown spectroscopy (LIBS) and machine learning to trace the origins and predict elemental content in Hypericum perforatum L. (HPL). LIBS data were collected from 269 HPL samples across various regions, while inductively coupled plasma mass spectrometry quantified 15 elements. Eleven preprocessing methods were evaluated for their impact on models. We developed four origin traceability models and multi-element quantification models using a multi-output regression framework. Optimal spectral intervals were identified through a moving window algorithm, and bootstrap aggregating enhanced model accuracy. The 4–8 interval effectively distinguished samples from different origins, with the XGBoost model performing particularly well in identifying July-harvested HPL from Xinjiang. All models achieved R² values exceeding 0.8574, and paired t-tests showed no significant differences between actual and predicted values, confirming their effectiveness in origin identification and elemental content prediction.

Beyond its geochronological potential, zircon geochemistry is increasingly used not only for estimating formation temperature or identifying rock type and origin, but also for distinguishing magmatic, metamorphic and mineralization processes. Minor and trace elements (e.g., Al, P, Ti, Y, Yb, Lu, Hf, Th, and U) in zircon are informative, but high spatial resolution microanalysis techniques are urgently needed to address the limited size of zircon grains. Here, we developed a new EPMA method to determine minor and trace elements in zircon with high precision and accuracy. Detection limits and precision can be improved to several ppm level (e.g., Ti, 9 μg g⁻¹, 3σ) by using high acceleration voltage and high beam current combined with long counting time. The use of matrix-matched reference materials (GJ-1, Tanz, and Qinghu zircon) with well-characterized trace elements of interest is important for improving and monitoring the analytical accuracy. Careful background offsets and background regression models need to be obtained via high-sensitivity WDS scan on each target element. An exponential background regression model was applied to Ti, Al, Th, and U, whereas other elements required linear background regression. In addition, adjusting the calibration standard for Al and suppressing spectral interferences (e.g., P, Y, and Yb) enabled highly accurate EPMA measurements of trace elements below 1000 μg g⁻¹. The spatial resolution of EPMA in zircon analysis, even under extreme conditions (20 kV and 500 nA), remains below 3 μm, surpassing that of laser ablation inductively coupled plasma mass spectrometry. Using our protocols, we have successfully measured the contents of minor and trace elements in zircons from the Chang'E-6 lunar anorthosite sample. Overall, this improved EPMA method could broaden the applications of zircon composition to geological evolution processes of the Earth and the Moon.

Lithium–organo-sulfur batteries combine high specific capacities of sulfur-based materials with tunable properties and excellent cycle stability of organic components. The key to designing batteries for specific applications is to understand the correlation between structural and electrochemical properties. The structure of sulfur-containing polymers prepared via inverse vulcanization as well as the sulfur load can be tuned by varying the sulfur feed ratio. With a self-absorption corrected linear combination analysis of X-ray absorption spectra, the distribution of sulfur strand lengths is quantitatively determined for double redox-active organo-sulfur networks with varying sulfur loads used as cathode materials in lithium–sulfur batteries.