Journal of Analytical Atomic Spectrometry最新文献

Pyrrhotite is a common Fe sulfide mineral in meteorites and magmatic sulfide ore deposits. It can be used to trace the origin of metals, as well as the formation and evolution of ore deposits. The natural pyrrhotite reference materials have been extensively consumed with the development of in situ techniques. In this study, we synthesized pyrrhotite by the hydrothermal method and evaluated its suitability as a reference material for in situ Fe and S isotope analysis. The synthetic pyrrhotite obtained through a hydrothermal experiment exhibits uniform surfaces and dense structures. The electron probe microanalysis (EPMA) verified the homogeneity of the major elements. The results of laser ablation multiple-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) for the iron isotopes and secondary ion mass spectrometry (SIMS) for the sulfur isotopes demonstrate the homogeneity of Fe and S isotopes, respectively. For in situ microanalysis, the two standard deviations (2SD) of iron and sulfur isotope compositions of SY-Po are 0.47‰ (2SD, n = 30) and 0.53‰ (2SD, n = 133), respectively. The solution MC-ICP-MS analyses and isotope ratio mass spectrometry (IRMS) results for SY-Po determined that the best recommended δ⁵⁶Fe value is 0.39 ± 0.03‰ (2SD, n = 3) and δ³⁴S value is −1.16 ± 0.23‰ (2SD, n = 11). Synthetic pyrrhotite SY-Po is a new potential reference material for in situ Fe and S isotope microanalysis, intended for tracing the formation processes of Fe sulfide minerals in magmatic sulfide ore deposits and meteorites.

In this study, atmospheric pressure AC needle-to-needle bare electrode discharge coupled with a nebulized sample injection was developed for elemental analysis (Ni, Cu, Cd, and Pb). The effects of various parameters—including carrier gas composition, nebulizer gas flow rate, organic additives, solution pH, discharge power, and discharge gap—on the discharge mode and analytical performance were systematically investigated. Oxygen was identified as the optimal carrier gas due to its low background noise in the optical emission spectrum and favorable plasma properties. Importantly, the transition state between streamer and glow-like discharge was found to be most favourable for elemental analysis. Under optimized conditions (2.2 L min⁻¹ nebulizer gas flow rate, 2% methanol additive, 3 mm discharge gap, and 15 kV applied voltage), the device achieved sensitive limits of detection (LODs) for Ni (0.38 mg L⁻¹), Cu (0.05 mg L⁻¹), Cd (0.09 mg L⁻¹), and Pb (0.24 mg L⁻¹), with relative standard deviations (RSDs) ≤6.1% (n = 10), demonstrating its potential for portable and rapid elemental analysis applications.

Bioavailable fractions of micronutrients—including copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn)—which comprise only 1–20% of the total soil micronutrient content—are the primary forms accessible for plant absorption and physiological processes. Accurate and timely quantification of these fractions is vital for site-specific nutrient management in precision agriculture. This study presents a novel analytical method that combines laser-induced breakdown spectroscopy (LIBS) with a solid–liquid–solid transformation (SLST) protocol to address conventional detection technique limitations. This integrated method facilitates rapid, in situ, and highly sensitive detection of bioavailable micronutrients (Cu, Fe, Zn, Mn) in complex soil matrices. The results demonstrated that bioavailable micronutrients could be accurately and efficiently detected using the proposed method. The limits of detection (LoDs) for Cu, Fe, Zn and Mn were determined to be 0.06, 0.20, 0.98, and 0.71 mg kg⁻¹, respectively, meeting the classification standards of I–III categories in the classification of bioavailable elements in Chinese soil. Furthermore, the total detection time was reduced to less than 20 minutes, highlighting the method's efficiency for rapid soil assessment. This analytical approach offers a practical and innovative solution for real-time monitoring of soil nutrients, facilitating data-driven fertilization strategies for precision agriculture.

Building on the spectral stability and sensitivity of femtosecond laser-ablation spark induced breakdown spectroscopy (fs-LA-SIBS), and the pattern recognition capacity of deep learning, a DeepRNN spectral-statistical fusion framework is introduced for high-precision classification of industrial-grade steel alloys. The framework fuses two-channel raw spectra with statistical descriptors, and employs configurable bidirectional recurrent encoders (GRU, LSTM, and vanilla RNN) to capture temporal dependencies and shape a robust decision space under end-to-end training. Under a unified evaluation protocol, the DeepRNN framework models are benchmarked against CNN and Transformer, and against traditional machine learning methods including RF, SVM, and PLS-DA; wavelength contribution analysis is performed to identify discriminative regions and interpretable importance profiles. Under the DeepRNN framework, the three encoders consistently outperform CNN, Transformer, and traditional machine learning baselines on core metrics including accuracy, cross-split consistency, and perturbation robustness, with average accuracy improved by approximately 2.35 to 3.50 percentage points compared to CNN and Transformer, and by 6.58 to 15.40 percentage points relative to traditional baselines. They also achieve favorable trade-offs among accuracy, efficiency, and deployability, with wavelength importance aligning with physically meaningful line structures. This sensor-intelligent system enables scenario-oriented deployment: vanilla RNN is chosen when accuracy is paramount; GRU is suitable for low-latency, energy-constrained online monitoring; and LSTM is preferred for the most conservative optimization trajectory and robustness under complex conditions, providing a scalable pathway for real-time industrial alloy identification and quality control.

Solution cathode glow discharge-atomic emission spectrometry (SCGD-AES) demonstrates significant potential as a metal element detection technique. However, its direct measurement of complex matrices still faces challenges in reliability due to matrix effects. To address this issue, standard dilution analysis (SDA) calibration emerges as an innovative strategy capable of effectively overcoming matrix interferences. This study investigated the feasibility of combining SDA with SCGD for practical complex sample analysis by employing automated SDA to collect calibration points over time and establish analytical curves. The results demonstrated that the proposed SCGD-SDA method performed effectively, showing that the relative deviations between the SCGD and inductively coupled plasma optical emission spectrometry (ICP-OES) methods were 5.2–9.4% for Ca, 3.1–7.3% for Fe, and 2.8–7.5% for Zn in five different oral glucose solutions. The detection limits of automated SDA reach ppb levels. SDA compensates for instrumental fluctuations and matrix effects, providing improved accuracy compared to external standard calibration (EC) while maintaining good agreement with ICP-OES reference values. The SCGD-SDA method establishes a simple and rapid analytical approach for trace element determination in glucose oral solutions.

Laser-induced breakdown spectroscopy (LIBS) exhibits broad application prospects but suffers from poor signal stability, significantly compromising analytical precision. Correction of spectral signals using plasma optical signals is highly promising. The dynamic vision sensor (DVS), with microsecond temporal resolution and a dynamic range over 120 dB, is particularly suited to capturing plasma optical signals. This study presents a new approach that integrates a DVS into the LIBS system to capture key plasma parameters and provide effective correction for LIBS signals. To obtain high-quality spectral and plasma optical signals, comprehensive spectral analysis was first conducted to determine the optimal LIBS parameters of 95 mJ laser energy and 1.5 μs delay time. In parallel, DVS parameters were optimised using event frame reconstruction and statistical analysis, resulting in the configurations of an F2.0 aperture, 5 cm collection distance, and 0° collection angle. In addition, a spectral correction model (DVS-SC) was established, which utilises the plasma area and the number of “On” events generated by increased light intensity, as extracted by the DVS, to achieve signal correction. Experimental validation on copper alloys and carbon steel indicated that, compared with the original data, the calibration curve R² values for Cu I 327.396 nm, Zn I 328.233 nm, and Mn I 403.076 nm increased to 0.944, 0.956, and 0.941, corresponding to improvements of 61.1%, 49.8%, and 81.3%, respectively. The average relative standard deviations decreased to 3.173%, 10.317%, and 0.872%, respectively, demonstrating clear improvements over the original results. The method proposed in this study combines simplicity, cost-effectiveness, and high efficiency, thereby providing considerable practical value for on-site applications.

In the present study, a microwave-assisted ultraviolet digestion (MAWD-UV) method with diluted acids was evaluated as a sample preparation method for edible crickets for the subsequent determination of rare earth elements (REEs; Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) by inductively coupled plasma mass spectrometry (ICP-MS) with ultrasonic nebulization (USN). The use of diluted HNO₃, as well as the use of H₂O₂ and HCl, was evaluated in the digestion solution. When 15 mL of 3 mol L⁻¹ HNO₃ + 0.8 mol L⁻¹ HCl were used, quantitative results were obtained for all REEs (agreement >90% with the reference method – MAWD using concentrated HNO₃). The accuracy of the proposed method was evaluated by using a certified reference material (BCR-668, mussel tissue), and no significant difference was observed between the results and the certified values. Using the optimized conditions, REE concentration in blank solutions was always negligible. The digests obtained by MAWD presented high carbon (3604 mg L⁻¹) and acidity (2.9 mol L⁻¹) content, increasing the possibility of occurrence of non-spectral interferences during REE determination by USN-ICP-MS. The interferences presented are mainly due to differences in the properties of digests (viscosity, density, and surface tension) and the calibration solutions, requiring a high dilution factor before the determination step. The proposed method allowed the digestion of up to 500 mg of sample using 15 mL of 3 mol L⁻¹ HNO₃ + 0.8 mol L⁻¹ HCl, resulting in digests with low carbon (1370 mg L⁻¹) and acidity (1.0 mol L⁻¹) content. The proposed MAWD-UV method provided LOQs between 0.15 (Eu) and 37 ng g⁻¹ (Ce), allowing the determination of REEs at very low concentrations.

Management of material throughout the nuclear fuel cycle is critical in maintaining global nuclear security. Incorporating “double spiked” isotopic taggants into nuclear fuel is one method by which unique chemical signatures can be assigned to fuel components for later characterization and identification if material is found outside of regulatory control. While these taggants are characterized to the highest precision using multicollection inductively coupled mass spectrometer (MC-ICP-MS), the significant laboratory and personnel requirements to maintain multicollection instruments restricts their global use. In contrast, single collection ICP-MS are widely available and found in nearly every academic and national lab institution. This work explores if quadrupole-focused single collector ICP-MS can adequately characterize nuclear fuel isotopic taggants through a comparison with a MC-ICP-MS and modeled theoretically achievable precision. This comparison was enabled by producing enriched iron (Fe) isotope taggant endmembers (⁵⁴Fe and ⁵⁷Fe), which were then diluted with natural Fe to create a series of taggant solutions, with Fe isotopic compositions ranging from highly enriched to near-natural. These solutions were isotopically characterized using both MC-ICP-MS and quadrupole ICP-MS (Q-ICP-MS) equipped with a helium collision cell to investigate the precision and accuracy limits of these instruments in resolving taggant material from natural Fe. Precision on both instruments was lower than modeled theoretical (Poisson) precision, likely due to the combined effects of unresolved isobaric interferences impacting the Fe isotopic spectra and intrinsic plasma ion source noise. Both instruments are capable of resolving the taggant signature at a 1000× dilution with natural Fe, while only δ⁵⁷ perturbations could be resolved outside of uncertainty for the 10 000× dilutions. These results demonstrate that the more widely accessible Q-ICP-MS platform can be used to characterize taggants up to the 1000× dilution level. This capability will allow for dozens of unique isotopic “barcodes” to be synthesized and detected using commercially available, relatively affordable mass spectrometric instrumentation, and underscores the potential of modern Q-ICP-MS platforms in being able to quantify subtle isotopic differences in challenging material formulations.

Laser-induced breakdown spectroscopy (LIBS) is widely applied in elemental quantitative analysis due to its rapid response, in situ detection, and simultaneous multi-element measurement capabilities. However, self-absorption effects, especially in high-concentration samples or under resonant transition conditions, often cause nonlinearity in calibration curves, significantly compromising the accuracy of quantitative analysis. To address this issue, this study proposed a combined approach integrating magnetic field confinement with one-point calibration LIBS (OPC-LIBS) to mitigate self-absorption effects and thereby improve quantitative accuracy. Six certified standard aluminum alloy samples were selected to evaluate the method. The impact of the applied field on plasma properties and analytical performance was studied for both the major matrix element (Al) and trace alloying constituents (Mg, Cu, Fe, and Ni). The experimental results demonstrated that magnetic field confinement enhanced spectral intensity and electron temperature, while increasing electron density—a signature of plasma confinement. This led to a more stable and uniform plasma, which effectively decreased self-absorption. In terms of quantitative performance, magnetically confined OPC-LIBS exhibited higher linearity and accuracy compared to conventional OPC-LIBS. Moreover, the linearity and accuracy varied among different elements. Under optimal conditions, the coefficient of determination (R²) between the predicted and certified concentrations of Al and Fe increased from 86.67% and 97.57% to 98.89% and 99.85%, while the average relative error (ARE) decreased from 0.21% and 8.99% to 0.05% and 2.99%, and the root mean square error of calibration (RMSEC) dropped from 0.20 wt% and 0.1 wt% to 0.05 wt% and 0.02 wt%, respectively. These results confirm the synergistic advantage of combining magnetic field confinement with OPC-LIBS for self-absorption correction and precise quantitative analysis, providing an effective technical pathway for high-precision elemental detection in complex matrices.

Magnesium (Mg), iron (Fe) and calcium (Ca)—key rock-forming elements—play critical roles in numerous geological processes, making them invaluable tracers in geochemical studies. However, conventional methods for their separation often involve a series of individual purification protocols and repeated column procedures. This study introduces a rapid chemical separation scheme for Fe, Mg and Ca, suitable for diverse rock types, especially for high-Ca and low-Mg samples. This protocol begins with precipitation to remove alkali metals (K and Na), followed by sequential separation of Fe, Mg, and Ca under varying acidic conditions using a single elution protocol with 1.5 mL of AGMP-50 resin. For samples with the Ca/Sr ratio less than 100, additionally a TODGA resin column is incorporated to further separate Ca from Sr. The purified Fe, Mg and Ca fractions exhibited high purity and low procedural blanks, enabling precise isotopic analysis by multi-collector inductively coupled plasma mass-spectrometry (MC-ICP-MS) using a sample-standard bracketing (SSB) method. The method's validity was confirmed through analysis of ten international geological reference materials, with results accurately reproducing published reference values. Therefore, the protocol's efficiency, reproducibility, and adaptability demonstrate its suitability for high-precision isotopic studies for a wide range of geological samples.