Journal of Analytical Atomic Spectrometry最新文献

Determining halogen concentrations in inorganic materials is becoming increasingly important to satisfy environmental regulations. However, quantifying chlorine using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) is challenging, despite the merits of this method. We propose a method for determining the chlorine concentration in glass using femtosecond LA with a scanning galvo mirror system, coupled with tandem ICP-MS (ICP-MS/MS). Hydrogen was introduced into the collision-reaction cell to eliminate mass spectral interferences (quadrupole 1: ³⁵Cl⁺ (m/z 35) → quadrupole 3: ³⁵ClHH⁺ (m/z 37)). A 1 × 1 mm² ablation area was used to minimize sample heterogeneity. Using the proposed method with standard reference materials (SRMs) 610, 612, 614, and 616 (National Institute of Standards and Technology) as calibration samples, we determined the chlorine concentration in BAM-S005-A, a standard glass reference material with a composition similar to that of the SRM 61x series. The determined value of 244 ± 4.5 µg g⁻¹ (n = 6, average ± 95% confidence interval) is in excellent agreement with the certified concentration (247 ± 33 µg g⁻¹), demonstrating the high accuracy and low uncertainty of the method. The proposed method enables rapid analysis (within 10 min) and does not require harmful reagents or complicated pre-treatment. This approach can be readily extended to other materials, supporting safer, faster, and more reliable halogen analysis across research and industry settings.

Herein, a novel photochemical vapor generation (PVG) of platinum (Pt) is reported in a mixed formic (FA)/acetic acid (AA) medium. The PVG efficiency of Pt was largely enhanced by the addition of Co(II) or Mo(VI). A mixture of low concentrations of FA and AA was found to be markedly superior to either FA or AA alone for efficient PVG of Pt. Mo(VI) was first identified as a sensitizer for Pt. The developed PVG system was coupled to inductively coupled plasma mass spectrometry (ICP-MS), and limits of detection (LODs) as low as 0.04 ng L⁻¹ for the Mo(VI)-assisted system and 0.02 ng L⁻¹ for the Co(II)-assisted system were obtained (3σ, n = 11) under selected conditions. These LODs were 15–30 times lower than the recent reports concerning Co(II)/Cd(II) synergistically assisted PVG for Pt systems in AA medium alone, and no segmentation of the linear dynamic range was observed as well. The method was successfully applied to the determination of Pt in environmental water samples, and spike recoveries between 93% and 108% were obtained. Mechanistic studies were conducted separately for Mo(VI)- and Co(II)-assisted PVG reactions, and the volatile Pt species were inferred to be Pt(CO)_x(CH₃)_y in both systems. Upon UV irradiation, Co–Pt bimetallic nanoparticles were observed in the Co(II) system, whereas only Pt nanoparticles were detected in the Mo(VI) system, indicating that distinct sensitization pathways were followed by Co and Mo. This work provides a robust technical foundation for trace Pt analysis in aquatic environments and offers new scientific insights into the photochemical transformation of Pt in natural waters.

Delayed gas–liquid separation or shortened transport paths for hydride generation (HG) due to the easy decomposition of volatile zinc species under ambient conditions could result in decreased sensitivity and reproducibility in atomic spectrometric detection. Therefore, a new HG sampling device equipped with atomic fluorescence spectrometry (AFS) was designed to improve the detectability of trace zinc. This new device can simultaneously realize hydride generation and rapid gas–liquid separation and effectively shorten the transport path/time to the AFS, resulting in better analytical performance for zinc detection. Moreover, the addition of the modifier sodium diethyldithiocarbamate (DDTC) and Co²⁺ enhanced the detection sensitivity for zinc. Under selected experimental conditions, the limit of detection (LOD) for Zn was 0.1 µg L⁻¹, relative standard deviation (RSD) was 3.0% with a zinc concentration of 10 µg L⁻¹, and linear dynamic range was 1–200 µg L⁻¹ (R² = 0.999). The sensitivity and LOD were greatly improved in comparison with those obtained using the conventional HG-AFS for zinc detection.

The occurrence and mobility of rare earth element (REE)-bearing nanoparticles (NPs) play a crucial role in REE enrichment processes, yet their characterization at trace concentrations (from ng mL⁻¹ to ppb levels) remains challenging due to their heterogeneity and low abundance. Here, we present a high-resolution method combining hollow fiber flow field-flow fractionation (HF5) with UV-Vis spectrometry (UV) and inductively coupled plasma mass spectrometry (ICP-MS) for the in situ size separation and speciation of REE-bearing nanoparticles in complex matrices. In order to evaluate and optimize the system to achieve high-resolution nanoparticle fractionation, the variables of carrier solution composition, focusing time, radial flow rate, and axial flow rate were investigated in detail. Applied to weathered horizon samples from the Nan'an HREE deposit, this method revealed distinct size distributions and concentrations of REE-bearing nanoparticles via HF5-ICP-MS. Nanoparticles with particle sizes smaller than 80 nm dominated, accounting for 70% in the fully weathered horizon (FWH) and 87.8% in the semi-weathered horizon (SWH), with significantly higher concentrations in SWH than in FWH. Vertical distribution analysis showed that nanoparticles with smaller particle sizes correlate more strongly with REE enrichment. Correlations between REEs and Al, Fe, Mn peaks within the 20–80 nm particle size range indicated associations with clay minerals and Fe–Mn (oxyhydr)oxides. Additionally, HREE-bearing nanoparticles occurred at higher concentrations than LREE-bearing nanoparticles, consistent with deposit characteristics, thereby confirming nanoparticles as a major occurrence form of REEs. The HF5-ICP-MS results agreed well with the transmission electron microscopy (TEM) particle size data, demonstrating the method's reliability for nanoparticle size characterization in weathered horizons. This HF5-based approach provides a robust and applicable method for characterizing REE-bearing nanoparticles in complex horizon samples. It offers valuable insights into REE enrichment mechanisms and occurrence forms in IARDs, with broad implications for understanding nanoparticle-mediated REE mobility and enrichment in surface environments.

Thermal ionization mass spectrometry (TIMS) is a widely used mass spectrometric technique for trace/ultra-trace isotopic analysis. For accurate isotope ratio determination, the detector dead time and ion counter efficiency have to be appropriately corrected for. Two methods of pulse counting detector dead time calculation were evaluated on a TIMS instrument. Both methods were based on the measurement of Sr isotope ratios in NIST standards and had similar performance in assessing the dead time for pulse-count detectors. In addition, one of the newly proposed methods in this manuscript can be used to simultaneously determine the dead time and ion counter efficiency of the pulse counting detector via the ratio measurement approach. The advantages of using the method presented here are firstly that both the detector dead time and the ion counter efficiency can be obtained simultaneously and secondly that the sampling time can be spent entirely on the isotopes of interest.

Inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) has established itself as a valuable analytical technique for measurement of a range of medium- and long-lived radionuclides. The two quadrupole mass filters separated by a collision/reaction cell can achieve online separation of interferences that would otherwise prevent accurate measurement and can be used to support, and in some cases even replace, relatively time consuming offline chemical separation. A number of collision and reaction cell gases have been successfully used for separating radionuclides from interferences, including H₂, He, O₂, NH₃, CH₄ and CO₂. One gas that has been used for several stable isotopes but never for radionuclides is methyl fluoride (CH₃F). This work shows the first investigation of CH₃F as a reaction cell gas in ICP-MS/MS for online separation of radionuclides from isobaric interferences. Results are based on a combination of radionuclides and stable analogues along with their isobaric interferences in standard solutions. A range of cell products were investigated, with promising separation schemes for several radionuclides including ^59/63Ni, ⁹⁰Sr and ^135/137Cs. The results show the potential to further extend the applications of ICP-MS/MS for radionuclide measurement.

Correction for ‘Cadmium isotopes analysis of environmental samples with high organic matter by dry ashing method under wet plasma conditions’ by Xian Wu et al., J. Anal. At. Spectrom., 2024, 39, 2298–2308, https://doi.org/10.1039/D4JA00083H.

Resonance ionization mass spectrometry (RIMS) is a highly sensitive technique for isobar-free analysis of long-lived isotopes, leveraging its exceptional elemental selectivity. However, the inherent laser-induced isotopic discrimination (LIID) in RIMS has posed challenges for its application in high-precision isotope ratio analysis. To address this limitation, based on the experimental phenomena observed in the analysis of Sn isotope ratios using RIMS, we investigated how isotope mass and isotope shift affect ionization efficiency, and proposed a semi-empirical internal standard correction method for LIID. Additionally, the combination of the total evaporation method, which is commonly used in thermal surface ionization mass spectrometry (TIMS), with RIMS effectively corrects the influence of mass fractionation on ratio measurements, thereby decoupling the LIID from the mass fractionation. This novel internal correction model for LIID enables RIMS, for the first time, to perform isotope ratio measurements with internal calibration capabilities comparable to those of TIMS and inductively coupled plasma mass spectrometry (ICP-MS). The application of this correction method to Sn isotopes has led to a tenfold improvement in both precision and accuracy. Post-correction analyses demonstrated isotope ratio determinations with precision better than 0.05% and accuracy exceeding 0.1%. This advancement significantly expands the potential of RIMS in fields that demand strict isotopic fidelity, such as nuclear forensics, the nuclear industry, and environmental tracer studies.

Lithium (Li) isotope ratios (expressed as δ⁷Li) are increasingly utilized as tracers for environmental and biological processes, including recent studies on Li uptake by living organisms and its emerging role as a contaminant. However, the typically low Li concentrations in natural samples and sentinel species used for monitoring present significant analytical challenges, particularly in generating efficiently high-precision and accurate isotopic data. In this study, we present the results of multiple tests and an optimized protocol for Li isotopic analysis at ultra-trace levels (<3 ng Li) using the Neoma MC-ICP-MS. We also provide long-term, high-precision isotopic data for marine and biological reference materials. First, we demonstrate that memory effects remain significant when analyzing low-concentration Li solutions. However, reducing the sample volume to 550 µL effectively minimizes these effects to just 3% of the ⁷Li signal. Our findings confirm that the Standard Sample Bracketing (SSB) method is effective for low-level Li isotopic measurements, though several precautions are necessary. Specifically, the molarity of nitric acid used for sample and LSVEC (bracketing standard) dilution must be carefully matched, with deviations of less than 0.3%. Additionally, the relative difference in ⁷Li voltages between standards and samples needs to be within ± 20% to avoid significant isotopic bias. Furthermore, we directly compared two desolvating systems (Apex Ω and Aridus III) for Li isotopic analysis under dry plasma conditions. This comparison enabled us to propose an optimized introduction system for nanogram-level analyses with minor memory effects. We then applied our protocol to multiple analyses of four reference materials (Li7-N; AEL, EDMM-1-H seawater; NIST SRM 1400; PLK-VLFR), demonstrating efficient data acquisition with excellent long-term accuracy and precision for both marine and biological matrices. Future efforts should focus on reducing the time required for Li dissolution and purification from samples used in high-frequency environmental and bio-monitoring applications.

Natural silicate glasses are widespread in diverse geological and planetary settings. The oxidation state of iron (Fe) preserved within these glasses is highly sensitive to variations in oxygen fugacity (fO₂) during their formation, providing critical constraints on magmatic evolution, volcanic processes, and planetary surface oxidation histories. X-ray photoelectron spectroscopy (XPS) is a crucial technique for determining the valence of Fe. Conventional approaches using Fe 2p XPS are often limited in complex silicate systems due to overlapping peaks and interference from satellite structures, which could reduce the accuracy of spectral fitting. Fe 3p XPS spectra, on the other hand, are more suitable for quantitative analysis due to their straightforward spectral characteristics. Despite this benefit, a systematic quantitative framework and standardized calibration method for Fe 3p analysis have not been fully developed yet. In this study, a quantitative analytical method has been developed for quantification of the Fe³⁺/ΣFe ratio from Fe 3p XPS spectra, using a series of basaltic synthetic glasses as reference materials. We have systematically investigated the effects of the binding energy position, peak fitting strategy, beam spot size, and scan repetition on spectral stability and quantification of the Fe³⁺/ΣFe ratio. Based on these evaluations, a robust correlation has been established between the Fe³⁺/ΣFe ratio and the Fe 3p peak area ratio. Two universal calibration curves have been constructed at different beam spot sizes. The reliability of the two curves has been validated using a leave-one-out cross-validation method, yielding root mean square errors (RMSEs) of 0.03 and 0.04, respectively. These results showcase a practical Fe valence quantification method of Fe 3p-based XPS for complex silicate glasses, highlighting the potential for integrating advanced spectroscopy methods into broader geological research frameworks.