Abstract:Tianwen-1’s MarSCoDe payload acquires chemical compositions of Martian rocks and soils. Previous LIBS models, built with Earth-based simulated Martian spectra, face accuracy reduction due to environmental discrepancies between simulations and the real Martian surface. To address this issue, this study establishes a univariate quantitative model for major elements based on in-situ Martian MCCT LIBS spectra. The derived Root-Mean-Square Errors are comparable to those reported in previous studies, and the average elemental compositions are consistent with GRS measurements at the Tianwen-1 landing site. Based on model-derived compositions and low Chemical Index of Alteration (CIA, 21.5% ± 8.0%), most rocks and soils show overall weak chemical alteration, implying limited water–rock interactions in the Tianwen-1 landing area during the Late Hesperian to Amazonian. Nonetheless, several samples with CIA values exceeding 35% (up to 42.7%) record localized liquid water activities within the region during this period.

Abstract:Coal analysis plays a crucial role in its efficient utilization and pollution control. Laser-induced breakdown spectroscopy (LIBS) exhibits promising application prospects in coal quality analysis because of its uniquely rapid and minimally destructive capabilities. However, the complex composition of coal induces severe matrix effects, which pose a formidable challenge to the accurate quantification in traditional LIBS analysis. In this study, a novel method named spectrum-ultrasound-image multi-modal fusion model (SUI-MM) was introduced to mitigate matrix effects in coal and improve the quantitative performance. SUI-MM extends conventional LIBS to a homologous multi-modal analysis framework combining spectra, ultrasound, and image, effectively compensating for the absence of physical structural and plasma spatial morphological information in spectra. By establishing a three-dimensional feature extraction and fusion strategy, it enables comprehensive characterization of coal plasma behavior and further improves quantitative performance. To verify the effectiveness of SUI-MM, experiments were performed on elemental and proximate analysis of coal. For the elemental analysis, the average R2p is improved to above 0.998, while RMSEp and AREp are reduced by 88% and 90%, respectively. For the proximate analysis, the average R2p is increased to over 0.999, and both RMSEp and AREp are decreased by 91% on average. Furthermore, ablation experiments confirm that image and ultrasonic signals contribute significantly to the improved analytical performance. These results demonstrate that the SUI-MM scheme can effectively mitigate matrix effect and significantly improve the quantitative accuracy in coal. In summary, SUI-MM is expected to further support the low-carbon transition of the energy industry.

Abstract:Neutron depth profiling (NDP) is a non?destructive, operando technique that directly quantifies lithium distribution and transport in all?solid?state batteries (ASSBs) by exploiting the 6Li(n, α)3H nuclear reaction. Conventional techniques (e.g., X?ray methods) rely on interactions with extranuclear electrons and thus struggle to detect lithium due to its low electron density. By contrast, NDP exploits the direct nuclear reaction, enabling unambiguous localization of 6Li atoms. Consequently, NDP provides quantitative, depth?resolved monitoring of lithium concentration profiles along the battery thickness direction with a typical depth resolution of tens of nanometers. This review systematically summarizes recent progress in applying NDP to four key aspects of ASSBs: electrolytes, electrodes, interfaces, and thin?film full batteries. In electrolytes, NDP has revealed electronic?conductivity?induced random dendrite nucleation and reversible short?circuit phenomena. In electrodes, it has guided 3D framework designs, validated surface halogenation for Si anodes, and verified longitudinal Li gradients in composite cathodes. In interfaces, NDP has visualized space?charge layers, quantified lithiophilic coating effects, and provided early detection of short?circuit failure. In thin?film batteries, NDP has tracked Li?ion transport in near real time using isotopic tracers, identified Si migration as a degradation mechanism, and pinpointed rate?limiting interfaces in combination with other techniques. Beyond these applications, the inherent advantages and current limitations of NDP—such as its sensitivity to 6Li isotope, the trade?off between depth resolution and counting statistics, and the requirement for flat sample surfaces—are critically discussed. This review establishes NDP as an indispensable tool for understanding and engineering lithium transport in ASSBs, and outlines future directions including higher?flux neutron sources, improved detector systems, and integration with complementary in situ probes.

Abstract:In this study, a robust analytical method based on high performance liquid chromatography coupled to inductively coupled plasma - tandem mass spectrometry (HPLC-ICP-MS/MS) was developed and validated for the simultaneous determination of ethylene thiourea (ETU) and propylene thiourea (PTU) in fruits and sulfur-rich vegetables such as plums, apricots, cherries broccoli and Brussels sprouts. Sample preparation was based on a Quick Polar Pesticides (QuPPe) extraction using methanol, followed by an anion-exchange solid-phase extraction (SPE) cleanup to efficiently remove sulfur-containing matrix interferences released during homogenization. Method validation was carried out according to the accuracy profile approach (NF V03-110) across five levels (10-400 μg L?1) for each of the matrices mentioned above. The method showed satisfactory trueness, repeatability, and intermediate precision for both analytes, with limits of quantification of 10 μg L?1 for both ETU and PTU in all matrices. The proposed method demonstrates strong robustness and versatility for the determination of ETU and PTU in challenging sulfur-rich plant matrices and provides a promising ICP-MS/MS-based alternative for the quantification of sulfur-containing organic contaminants in food.

Abstract:Laser-induced breakdown spectroscopy (LIBS), as an in situ and real-time diagnostic technique, has proven effective in acquiring elemental distribution information under extreme operational conditions. Under the actual operating conditions of tokamak devices, the ablation angle and gas atmosphere exert a synergistic influence on the evolution behavior of laser-ablated plasma. However, the underlying physical mechanisms have not yet been fully elucidated, necessitating more systematic and in-depth investigations. The LIBS characteristics of laser-ablated W plasma under low-pressure (100 Pa) Ar, He, N2 gases and various incident angles were systematically investigated. LIBS spectra revealed that at low laser energy density, Ar promotes more effective electron collision excitation and plasma recombination, while the higher thermal conductivity of He facilitates free expansion of the plasma. In N? atmosphere, the signal-to-background ratio (S/B) of laser-ablated W plasma remained largely independent of the angle, which aids in optimizing LIBS signal stability. As the laser-ablated angle increases, the laser energy density decreases, leading to reduced stability and symmetry of the plasma plume. Further research indicates that as laser energy density decreases, the axial expansion of the W plasma plume remains nearly unchanged, whereas the radial expansion decreases rapidly. This study elucidates the evolution mechanism of the laser-ablated W plasma under the synergistic effects of ablation angle and gas atmosphere. The results provide an important theoretical basis for the geometric calibration and optimization of in situ LIBS diagnostic systems intended for operation under low-pressure conditions.

Abstract:A laboratory-assembled laser-induced breakdown spectroscopy instrument consisting of a compact low-power diode-pumped solid-state laser and a palm-sized low-resolution non-gated spectrometer was evaluated for the quantification of lithium in lithium-bearing ore. Five ore materials containing 0.468 – 2.67 wt.% lithium were analyzed. Three Li I emission peaks at 610, 670, and 812 nm were used after total-intensity normalization. The total-intensity normalization produced a modest improvement in intra-pellet precision but a much larger improvement in calibration accuracy by effectively reducing inter-pellet variation. All three peaks yielded good univariate linear calibration. Among the unconstrained single-peak models, the 670 nm peak showed the lowest prediction error, whereas the 812 nm peak became the best univariate variable when a zero-intercept model was applied, owing to its near-ideal sensitivity and minimal self-absorption. Multilinear regression showed that the combination of the 610 and 812 nm peaks gave the best prediction performance in leave-one-ore-out cross-validation, outperforming all univariate models. In contrast, the use of all three variables did not improve the model further because of strong multicollinearity among the Li peak intensities. These results demonstrate that reliable lithium quantification can be achieved with a low-cost LIBS instrument and that careful selection of a small number of physically meaningful and complementary spectral variables is more important than simply increasing model complexity.

Abstract:Remote quantitative laser-induced breakdown spectroscopy (LIBS) of nuclear fuel materials is a challenging task due to unstable laser delivery and limited plasma emission collection stability. Establishing robust fiber-optic LIBS (FO-LIBS) systems with optimal operational stability is demanding. This study develops a high-throughput FO-LIBS system for quantitative analysis of CeO?-based surrogate nuclear fuel. It incorporates a 10 m, 1 mm core multimode silica delivery fiber, a compact flat-top focusing probe, and a six-channel off-axis emission collection module with a broadband (180–900 nm) detection system. Beam profiling demonstrated that the incident Gaussian beam was transformed into a homogenized flat-top profile after fiber transmission, resulting in improved plasma stability and repeatability. Over 100 consecutive shots, the system achieved a transmission efficiency of approximately 54% with pulse energy variations of less than 2%. The full-spectrum had a relative standard deviation (RSD) of less than 5%. Internal standard normalization using Ce II emission lines produced highly linear calibration curves for La I and Nd II transitions (R2 > 0.99). These findings indicate that the developed FO-LIBS system displayed stable and reproducible quantitative performance, while its detachable probe configuration provides potential flexibility for remote analysis across multiple hot cells in radiation constrained environments.

Abstract:Long-term online monitoring of metals in surface water is essential to protect water resources. Herein, a novel, integrated analytical system encompassing an automatic sample preparation system and solution cathode glow discharge-optical emission spectroscopy (SCGD-OES) for continuous and real-time detection of metals in rivers is presented. A piston pump integrated with a switching valve in the SCGD-OES system enables on-site preparation of water samples and controlled injection of a standard solution with a gradient concentration or environmental samples directly into the SCGD unit. Corresponding hardware and software platforms were developed to support automated operation. Under laboratory conditions, the achieved limits of detection (LODs) for typical metal ions, e.g., Na, K, Ca, and Mg, are comparable to those of conventional SCGD setups. The evaluation of the SCGD system using certified reference materials (CRMs) for water samples demonstrated satisfactory performance for elemental quantitative analysis, with relative errors of 4.1%, 1.9%, 4.0% and 4.5% for the four elements Na, K, Ca and Mg respectively. Furthermore, a seven-day field deployment of the SCGD system at a riverine site confirmed its accuracy and stability, with a relative error of less than 5.7% relative to reference ICP-OES measurements. These results validate the ability of the SCGD system to provide reliable and continuous online monitoring of metals in surface water.

Abstract:The elemental composition of medicinal materials (MMs) is directly linked to their therapeutic efficacy and clinical safety, making the development of accurate, efficient, and green analytical strategies of elements critically important. This review systematically evaluates recent methodological advancements in elemental analysis (covering both essential elements and toxic heavy metals) in MMs. Firstly, it highlights innovations in green sample pretreatment technologies, including efficient digestion or extraction techniques. Secondly, it comprehensively compares the performance and application scenarios of various analytical techniques, each offering distinct advantages in sensitivity, multi-element analysis capability, and on-site applicability. Subsequently, the review examined the potential influence of elements on the pharmacological activity of MMs and the migration patterns of various elements in the “soil-medicinal plant” system. Finally, it systematically elaborates on precise health risk assessment models, emphasizing the necessity of shifting from total content analysis to a risk-oriented evaluation paradigm. This review aims to provide a comprehensive reference for the development of green analytical methods, risk assessment, as well as quality and safety control of MMs.

Abstract:Olivine is a key mineral of mafic-ultramafic and metamorphic rocks. Oxygen isotopic composition of olivine has been widely used to decipher mantle processes, igneous differentiation, and fluid-rock interaction in metamorphic systems. Accurate in situ oxygen isotopic analysis of olivine by secondary ion mass spectrometry (SIMS) requires matrix-matched reference materials to correct instrumental mass fractionation and monitor the stability of instrument. In this study, we report two natural olivine reference materials, AOL (Fo: 91-97) and POL (Fo: 94-97), for in situ oxygen isotopic analysis. These samples exhibit homogeneous oxygen isotopic compositions, with a two-standard deviation of 0.33‰ (N = 105) and 0.37‰ (N = 105), respectively. The recommended δ1?O values, determined by laser fluorination isotope ratio mass spectrometry, are 5.52 ± 0.25‰ for AOL and 5.64 ± 0.13‰ for POL (all ± 2SD, N = 5). Combined with previously reported olivine standards, our results confirm that no significant matrix effects were observed within the forsterite (Fo) content range of Fo?? to Fo??, supporting the wide use of AOL and POL as reference materials for high?precision oxygen isotopic microanalysis.