Journal of Analytical Atomic Spectrometry最新文献

Clinopyroxene oxygen isotope compositions provide critical insights into diverse geological processes. In situ oxygen isotope analysis is preferred over bulk methods because of complications such as inclusions, alteration, and isotope heterogeneity, all of which are common in natural clinopyroxene samples. Secondary ion mass spectrometry (SIMS) enables precise in situ oxygen isotope analysis at a spatial resolution of 10–15 µm. However, accurate SIMS results require homogeneous reference materials (RMs) that match the chemistry and crystal structure of the target minerals. Despite the wide compositional variability of natural clinopyroxenes, the number of available oxygen isotope RMs is limited. In this study, we characterize Cat–87 clinopyroxene as a new RM for oxygen isotope microanalysis. The major element composition of Cat–87 (Wo_36.0En_55.2Fs_8.8; Wo = wollastonite, En = enstatite, Fs = ferrosilite) expands the compositional coverage of available clinopyroxene RMs, and multiple SIMS measurements demonstrate its oxygen isotope homogeneity. A laser fluorination δ¹⁸O value of 5.53 ± 0.14‰ (2SD) is recommended as the reference value for Cat–87. Evaluation using eight Ca–Mg–Fe clinopyroxenes with variable chemistry demonstrates that Cat–87 is suitable for SIMS clinopyroxene oxygen isotope analysis in the compositional range Wo_33.8–37.6En_51.6–58.0Fs_8.2–11.0. In contrast, Cat–87 is not suitable for clinopyroxenes with higher Ca contents (Wo_44.6–47.5En_48.3–50.2Fs_3.7–7.2).

To meet the requirements of in situ planetary surface analysis, this research designed a miniature laser ablation nonaxial time-of-flight (TOF) mass spectrometer, which enables qualitative and semi-quantitative analysis of the samples' elemental and isotopic compositions. To achieve high performance under a compact architecture, a compact non-axial configuration was designed and comprehensive integrated simulations of the mass analyzer were performed. Simulation results indicated that the system can achieve a mass resolution of 1025 (FWHM) and an ion transmission efficiency of 15.15% while maintaining a compact design with a volume of ϕ58 mm × 172 mm. Experimental verification has shown that the mass resolution of aluminum alloy samples can reach 300 (FWHM) and the dynamic range can be extended over five orders of magnitude. In the semi-quantitative analysis of the isotopic abundance ratios of different samples, the relative accuracy was within 5%. Leveraging the advantages of pulsed lasers, the system can complete up to 1000 single spectrum measurements per second, with a spatial resolution of 15 µm. In addition, the system does not require complex sample preparation and has the advantages of miniaturization, low power consumption, and rapid full-spectrum scanning, making it suitable for on-orbit elemental measurement and in situ measurement of extraterrestrial planets.

Domestic energy use and indoor human activities generate substantial carbon emissions, making accurate monitoring of indoor carbon concentrations essential for identifying emission sources and assessing associated exposure risks. Laser-induced breakdown spectroscopy (LIBS) enables rapid, multi-element, and in situ detection of aerosols, exhibiting excellent sensitivity to carbon-related spectral characteristics. Combining LIBS with machine learning allows accurate prediction of carbon content by leveraging complex spectral patterns, with systematic hyperparameter optimization using the Sparrow Search Algorithm (SSA) and interpretable insights from SHapley Additive exPlanations (SHAP) analysis. Regression models, including Random Forest (RF), support vector regression (SVR), and least squares support vector machine (LSSVM), were applied to quantify spectral contributions and reveal the relationships between spectral features and carbon concentration. The models achieved high predictive accuracy, with R² values of 0.976 (RF), 0.979 (SVR), and 0.980 (LSSVM) for candles, and 0.943 (RF), 0.952 (SVR), and 0.980 (LSSVM) for fruit charcoal, demonstrating their overall effectiveness in carbon content analysis, with LSSVM showing slightly superior performance. To capture temporal spectral dynamics, a dynamic time-series prediction model was constructed by coupling an attention mechanism with a bidirectional long short-term memory (Bi-LSTM) network. This model successfully forecasts carbon concentration trends by learning long-range dependencies and salient temporal features, achieving R² values of 0.929 for candles and 0.882 for fruit charcoal. Overall, the integrated LIBS–machine learning approach enables fast, accurate, and interpretable carbon detection, substantially enhancing the precision of carbon source attribution and providing a scientific basis for indoor air quality monitoring and emission source management.

Sphalerite has been extensively utilized for tracing geological processes through its zinc and sulfur isotopic microanalysis. However, the lack of matrix-matched reference materials with characterized zinc and sulfur isotopic compositions poses a challenge. In this study, we examined a natural sphalerite sample (IGGSph-1) to evaluate its potential as a matrix-matched reference material for in situ microanalysis of zinc and sulfur isotopes. Electron probe microanalysis (EPMA) confirmed the homogeneity of major elements without any growth zoning in sphalerite grains. Random spot isotopic analyses conducted using laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) yielded variances in δ⁶⁶Zn and δ³⁴S of 0.07‰ (2S, N = 105) and 0.12‰ (2S, N = 105), respectively. Based on the results and statistical analysis, it was determined that the IGGSph-1 sample was isotopically homogeneous and had the potential to be used as a reference material. The δ³⁴S_VCDT value, measured using elemental analysis-isotope ratio mass spectrometry (EA-IRMS), was 16.35 ± 0.26‰ (2S, N = 6). Additionally, the δ⁶⁶Zn_JMC-Lyon value, measured using solution-nebulization multi-collector inductively coupled plasma mass spectrometry (SN-MC-ICP-MS), was 0.17 ± 0.04‰ (2S, N = 18). These values are recommended as the isotopic reference values for IGGSph-1.

The integration of LIBS and LA-ICPMS allows for simultaneous determination of a wide range of elements and isotopes. Achieving high-precision quantitative analysis in this dual-technique approach requires establishing the optimal gas environment in the sample chamber. This study evaluated the impact of gas flow on a tandem femtosecond LIBS and LA-ICPMS system. By premixing helium and argon at various ratios, we created gas mixtures with gradient properties. NIST SRM 610 was used as the standard sample to assess the signal intensity and stability of optical emission spectroscopy and mass spectrometry. Our results showed that the LIBS intensity of Li(I) 610.35 nm, Li(I) 670.77 nm and Ca(I) 644.90 nm, along with their relative standard deviation, increased with the proportion of argon in the gas mixture. Conversely, the LA-ICPMS intensity and relative standard deviation of each element decreased with the argon proportion in the carrier gas. LIBS appears to favour an argon ambient gas, while LA-ICPMS prefers helium as the carrier gas. To balance both modules, we tested various helium and argon gas mixtures. A mixed gas composed of 700 ml min⁻¹ helium and 400 ml min⁻¹ argon was found to be the optimal gas flow for the tandem system, considering signal intensity and relative standard deviation. This study highlights the significant influence of gas flow in optimizing the signal of optical emission spectroscopy and mass spectrometry in a tandem system, enhancing the precision and accuracy of elemental analysis for both modules.

Sustainable soil fertility ensures long-term productivity and food security. In intensively cultivated systems, imbalanced synthetic fertilization depletes nutrients and degrades soil. Integrating organic inputs can curb elemental imbalances and improve soil health. This study assesses the environmental and agronomic impacts of four fertilization strategies on soil quality and wheat productivity across 33 farms in Punjab, India: (1) farmyard manure (FYM; ∼6000 kg ha⁻¹), (2) diammonium phosphate + urea (DU; 130 + 130 kg ha⁻¹), (3) DU + FYM (DUF), and (4) DU + FYM + micronutrients Fe and Zn (DUFZ). Soil samples were analyzed for pH, EC, OC, macronutrients (N, P, and K), and micronutrients (Na, Mg, Al, Ca, Fe, Mn, and Zn) using standard protocols and advanced techniques (INAA, PIGE, and EDXRF). FYM-treated soils showed the highest OC (1.17%) and Ca levels, while DU raised EC and caused acidification (pH 6.82 ± 0.1). Integrated treatments improved micronutrient levels and yield, with DUFZ recording the highest wheat productivity (21.78 q per acre). However, excess N, P, and K depletion were noted. Mn concentration (667 ± 29 mg kg⁻¹) exceeded the MCA (500 mg kg⁻¹), and Zn levels surpassed 200 mg kg⁻¹, indicating potential environmental risks and degraded food quality. Multivariate analyses (PCA and HCA) indicated distinct clustering and a strong Zn and Mg synergism under integrated fertilization practices, highlighting enhanced soil nutrient status. The observed link between elevated Zn and Fe concentrations under integrated regimes suggests a potential cause of reported regional micronutrient deficiencies and associated public health burdens. This study offers an evidence-based vision for sustainable soil fertility management with benefits for both agroecosystem integrity and human nutrition.

The accurate in situ determination of sub-ppm to ppb-level trace elements, particularly rare earth elements (REEs), in olivine remains a significant analytical challenge due to their extremely low concentrations. This study presents a systematic evaluation and optimization of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for olivine trace elements analyses. We focused on enhancing the performance of a widely accessible quadrupole ICP-MS (Q-ICP-MS) and compared its capabilities with a high-resolution sector-field ICP-MS (SF-ICP-MS). A robust analytical protocol was developed for the LA-Q-ICP-MS by employing a large spot size (160 µm) at a high repetition rate (20 Hz). Crucially, a tailored dwell time strategy was implemented to accommodate the contrasting abundance of major elements (Mg and Fe) and ultra-trace REEs, enabling their simultaneous and accurate quantification. The accuracy of the method was rigorously validated using the matrix-matched olivine reference material MongOL Sh11-2, yielding REE concentrations consistent with recommended values down to the ng g⁻¹ level. The protocol was subsequently applied to metamorphic olivines from serpentinites in the Dabie-Hong'an Orogenic Belt. The metamorphic olivines from the Dongjiashan serpentinite exhibit higher concentrations of some incompatible and immobile elements such as Al, Ti, Ga, Y, Zr, and REEs than those from Yinshanzhai. Furthermore, some Dongjiashan olivines display U-shaped REE patterns. Collectively, these geochemical signatures provide compelling evidence supporting that the mantle wedge protolith of the Dongjiashan serpentinite experienced a higher degree of cryptic melt metasomatism. This work establishes a highly sensitive and widely accessible analytical protocol that significantly extends the capabilities of LA-Q-ICP-MS for measuring low-content trace elements in olivine.

Water quality monitoring is essential for protecting ecological systems and public health. However, conventional analytical techniques are often constrained by complex sample pretreatment, long analysis time, and limited suitability for on-site applications. Laser-induced breakdown spectroscopy (LIBS), as a rapid and multi-element analytical technique requiring minimal sample preparation, has emerged as a promising alternative for water analysis. This review systematically summarizes recent progress in LIBS-based water quality monitoring, covering its fundamental principles, technological developments, and practical applications. Emphasis is placed on advances in elemental detection relevant to water quality, including heavy metals, nutrient-related elements, and halogen elements. Various sample pretreatment strategies, signal enhancement techniques, and spectral data processing methods are critically reviewed, with particular attention to approaches that mitigate the coffee ring effect in aqueous environments. In addition, recent developments in integrated and portable LIBS detection systems are discussed, highlighting their potential for real-time and on-site monitoring. Finally, current challenges and future research directions for improving detection sensitivity, analytical reliability, and system integration are outlined. This review aims to help readers better understand the research needs of LIBS in the field of water quality monitoring.

Analytical techniques that offer accurate, sensitive, and high-resolution elemental mapping have significantly advanced our understanding of the role of inorganic chemistry in vital biological processes. Among these, synchrotron-based X-ray fluorescence microscopy (XFM) is a particularly powerful tool for providing reliable, non-destructive quantitation of endogenous elements in biological specimens. However, its broader application is constrained by limited beamtime availability. Recent advancements in laboratory-based imaging techniques—such as laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOF-MS)—have significantly increased the availability and throughput of elemental mapping. Yet, quantitation with LA-ICP-TOF-MS is susceptible to matrix effects, making correlative mapping with XFM critical for validation. This presents a challenge: the two techniques require different sample preparations. LA-ICP-TOF-MS uses glass slides, while XFM requires thin, low-scatter substrates to minimize X-ray background signals. To address this, we evaluated twelve commercially available substrates previously reported for XFM to determine their suitability for LA-ICP-TOF-MS. Our goal was to identify substrates that (1) exhibit low elemental background and minimal interference with quantifying endogenous inorganic species, and (2) are compatible with both imaging modalities. As an initial step, we compared adjacent brain sections prepared on Ultralene (for XFM) and glass (for LA-ICP-TOF-MS) to establish a baseline correlative approach. Building on this, Ultralene, followed by Kapton film, emerged as the most promising candidates for enabling dual XFM and LA-ICP-TOF-MS workflows, offering low background, reliable XFM performance, and demonstrating robust elemental mapping in LA-ICP-TOF-MS. These findings support more accurate and accessible correlative imaging workflows for elemental mapping of biological samples with both modalities.

Laser-induced breakdown spectroscopy (LIBS) often suffers from significant signal fluctuations in the quantitative analysis of alloy elements in steel. Although the conventional internal standard method is commonly employed due to its simplicity, it critically depends on the presence of an internal standard element at a high and stable concentration as well as on the expert-driven manual selection of spectral lines. To address these limitations, this study introduces an internal standard method based on image features (ISIF) and proposes two novel fusion approaches by integrating ISIF with image-assisted (IA) and spectral normalization (SN) methods, designated as ISIF-IA and ISIF-SN, respectively. Experimental results demonstrate that the standalone ISIF approach slightly improves the coefficient of determination (R²) for chromium and eliminates the need for manual spectral line selection, underscoring its applicability in complex matrix analyses. The fusion methods, ISIF-IA and ISIF-SN, substantially enhance the analytical accuracy, with particularly notable gains in the quantification of silicon and vanadium. Among these, the ISIF-SN method yielded the most significant improvement in signal stability, reducing the relative standard deviations (RSDs) of the validation samples for Si, V, and Cr from 19.66%, 17.34%, and 16.22% to 7.36%, 6.00%, and 3.45%, respectively. Additionally, both fusion strategies effectively mitigated the self-absorption effects in the Si and Cr spectral lines. This work confirms that coupling ISIF with IA or SN strategies markedly improves the quantitative analytical performance of LIBS in steel alloy analysis, thereby offering a robust and efficient approach for rapid and accurate in situ compositional assessment in industrial settings.