Spectrochimica Acta Part B: Atomic Spectroscopy最新文献_第7页

Quantitative LIBS imaging of cadmium in plant tissues with matrix-based calibration supported by micro-X-ray fluorescence spectroscopy 微x射线荧光光谱支持基质校准的植物组织中镉的定量LIBS成像

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-11-12 DOI: 10.1016/j.sab.2025.107389

Ludmila Čechová , Daniel Holub , Michal Kurka , Miloslav Pouzar , Pavel Pořízka , Jozef Kaiser

Laser-induced Breakdown Spectroscopy (LIBS) is an increasingly popular method for elemental bioimaging, primarily due to its fast and multi-elemental analysis. However, achieving quantitative accuracy is highly challenging, mainly due to the strong matrix effect present in biological matrices and the lack of spatially adaptive calibration strategies. When using the conventional pixel-to-pixel calibration approach, it typically assumes a uniform sample matrix, which leads to high quantification errors when applied to biological and plant tissues. Therefore, there is a need for novel calibration methods based on a delocalized approach that take matrix variability into consideration when dealing with biological samples. This study introduces a novel delocalized approach for quantitative bioimaging of elements, particularly cadmium (Cd) and calcium (Ca), in plant tissue. A controlled sample set of Cannabis sativa plants contaminated with three different Cd concentrations was analysed at matching spatial resolution using micro-X-ray fluorescence (micro-XRF) and LIBS. A conventional pixel-to-pixel calibration was initially employed as a baseline strategy but yielded high mean absolute percentage errors (MAPE) exceeding 40 % for Cd. Therefore, a delocalised approach was developed to overcome these limitations, leveraging clustering algorithms to construct a matrix-based calibration model. This method significantly improved quantification accuracy, reducing MAPE for Cd to as low as 8.7 %, while Ca quantification achieved a score of 1.1 % MAPE. The model also exhibited minimal bias, with errors in the parts-per-million range. These results demonstrate that advanced feature selection and clustering-based calibration enable accurate quantification in highly heterogeneous plant matrices. The proposed delocalized approach demonstrates a significant advance in LIBS imaging methodology by addressing a key limitation in pixel-to-pixel calibration and may be applicable to a broader range of elements in other biological and heterogeneous systems.

激光诱导击穿光谱（LIBS）是一种越来越受欢迎的元素生物成像方法，主要是由于其快速和多元素分析。然而，实现定量准确性是极具挑战性的，主要是由于生物基质中存在很强的基质效应和缺乏空间自适应校准策略。当使用传统的像素对像素校准方法时，它通常假设一个均匀的样本矩阵，这导致在应用于生物和植物组织时存在很高的定量误差。因此，需要一种基于离域方法的新型校准方法，在处理生物样品时考虑到矩阵的可变性。本研究介绍了一种新的离域方法，用于植物组织中元素的定量生物成像，特别是镉（Cd）和钙（Ca）。利用微x射线荧光（micro-XRF）和LIBS在匹配的空间分辨率下分析了受三种不同镉浓度污染的大麻植物对照样品。传统的像素对像素校准最初被用作基线策略，但Cd的平均绝对百分比误差（MAPE）超过40%。因此，开发了一种非局部化方法来克服这些限制，利用聚类算法构建基于矩阵的校准模型。该方法显著提高了定量精度，将Cd的MAPE降至8.7%，而Ca的MAPE评分为1.1%。该模型也显示出最小的偏差，误差在百万分之一的范围内。这些结果表明，先进的特征选择和基于聚类的校准能够在高度异质的植物基质中进行准确的定量。提出的离域方法通过解决像素到像素校准的关键限制，证明了LIBS成像方法的重大进步，可能适用于其他生物和异质系统中更广泛的元素。

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引用次数: 0

Improving limit of detection for Cr in total reflection X-ray fluorescence analysis via freeze concentration with double-internal-reference method 提高双内参法冻结浓度全反射x射线荧光分析中铬的检出限

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-11-12 DOI: 10.1016/j.sab.2025.107390

Tsugufumi Matsuyama , Airi Tsuji , Arinori Inagawa , Lee Wah Lim

We developed a sample preparation method for total reflection X-ray fluorescence (TXRF) analysis based on a freeze concentration technique to enhance sensitivity. To stabilize the frozen concentration, glycerol, which contains three hydroxyl groups, was added to the sample solution. We also developed a double-internal-reference method for simultaneously determining the concentration rate and the target element concentration before freezing. A Cr-containing sample solution was prepared as the target element, mixed with glycerol and Mn (first internal reference element), and then frozen. The exuded solution was collected and mixed with In (second internal reference element). The concentration rate was determined by comparing the X-ray fluorescence signals of the internal references, whereas the target element concentration was derived from the relationship between the fluorescent X-rays of the target and internal reference elements. Without freeze concentration, the limit of detection (LOD) for Cr using a portable TXRF instrument was 257 ng/mL. With freeze concentration and the addition of glycerol (0.05 mL), the average concentration rate was increased by 29.4-time, improving the LOD to 42.7 ng/mL, and a recovery rate of 100 % was achieved. The freeze concentration combined with a double-internal-reference was proven to be highly effective for sensitive TXRF analysis.

为了提高灵敏度，我们开发了一种基于冷冻浓缩技术的全反射x射线荧光（TXRF）分析样品制备方法。为了稳定冷冻浓度，将含有三个羟基的甘油加入到样品溶液中。我们还建立了一种双内参法，用于同时测定冷冻前的浓度速率和目标元素浓度。制备含cr的样品溶液作为目标元素，与甘油和Mn（第一内参元素）混合，然后冷冻。收集渗出液并与In（第二内参元素）混合。浓度速率是通过比较内参元素的x射线荧光信号来确定的，而目标元素的浓度则是由目标元素与内参元素的荧光x射线之间的关系来确定的。无冷冻浓度时，便携式TXRF仪器的检出限（LOD）为257 ng/mL。在冷冻浓度和添加甘油（0.05 mL）的条件下，平均浓度速率提高29.4倍，LOD达到42.7 ng/mL，回收率为100%。冷冻浓度与双内参相结合被证明对TXRF的敏感分析是非常有效的。

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引用次数: 0

Interference-free nitrogen detection under the atmospheric condition with LIBS in cements using a commercially available fiber laser 利用市售光纤激光器在大气条件下用LIBS检测水泥中的无干扰氮

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-11-10 DOI: 10.1016/j.sab.2025.107383

Tianyang Sun, Yunfei Rao, Li Wang, Ding Li, Haoyu Yang, Chen Sun, Jin Yu

Determination of nitrogen in solid-state materials using laser-induced breakdown spectroscopy (LIBS) under the atmospheric pressure faces the challenge of interference from nitrogen present in the ambient gas. Previous studies have proposed various strategies to address this issue, such as employing a vacuum chamber or purging the laser interaction zone with an inert gas, with the cost of increasing the complexity of a LIBS instrument. Fiber lasers with their recent industrial development present a promising opportunity for LIBS applications due to their inherent advantages, such as compactness, stability, and cost-effectiveness. Determination of a nonmetal element such as nitrogen in solid-state materials using a fiber laser remains to be demonstrated. Performing a such demonstration, with a particular focus on investigating an interference-free regime in LIBS operation, is precisely the purpose of this work. A series of nitrogen-bearing samples was prepared using cement as the matrix material and silicon nitride as the nitrogen-containing dopant. The experiments were conducted using a commercially available Q-switched Nd:YAG fiber laser operating at 1064 nm, with a pulse duration of 100 ns, a repetition rate of 5 kHz, and a pulse energy of 640 μJ. The N I 744.2 nm emission line was clearly observed, and our investigation confirmed that it originated from the sample rather than the ambient gas. This enabled a univariate regression of the spectral intensity against the nitrogen concentration. To further improve the analytical performance, feature selection was combined with multivariate regression using the partial least squares (PLS) algorithm. The resulting model achieved a limit of detection (LOD) of 0.46 wt%, a relative error of prediction (REP) of 2.22 %, and a root mean square error of prediction (RMSEP) of 0.12 wt%. Such results represent a significant improvement with respect to the state-of-art performance for nitrogen determination in solid-state materials with LIBS, with for example a reported LOD of 0.8 wt% for a determination of nitrogen in sands (Harris et al., 2004 [1]), demonstrating thus the capability of fiber laser LIBS for accurate nitrogen determination in solid-state materials under the atmospheric conditions, without the need of additional equipment such as vacuum or gas purging systems.

常压下激光诱导击穿光谱（LIBS）测定固态材料中的氮面临着环境气体中氮干扰的挑战。先前的研究提出了各种策略来解决这个问题，例如采用真空室或用惰性气体净化激光相互作用区，但成本增加了LIBS仪器的复杂性。随着近年来的工业发展，光纤激光器由于其固有的优点，如紧凑、稳定和成本效益，为LIBS应用提供了一个有希望的机会。用光纤激光测定固态材料中的非金属元素，如氮，还有待证明。执行这样的演示，特别侧重于研究LIBS操作中的无干扰状态，正是这项工作的目的。以水泥为基体材料，氮化硅为含氮掺杂剂，制备了一系列含氮样品。实验采用市售调q Nd:YAG光纤激光器，工作波长为1064 nm，脉冲持续时间为100 ns，重复频率为5 kHz，脉冲能量为640 μJ。n744.2 nm的发射谱线清晰可见，我们的调查证实了它是由样品而不是环境气体引起的。这使得光谱强度对氮浓度的单变量回归成为可能。为了进一步提高分析性能，使用偏最小二乘（PLS）算法将特征选择与多元回归相结合。该模型的检出限（LOD）为0.46 wt%，预测相对误差（REP）为2.22%，预测均方根误差（RMSEP）为0.12 wt%。这些结果表明，相对于使用LIBS测定固态材料中氮的最先进性能而言，这一结果有了显著的改进，例如，据报道，LIBS测定沙子中的氮的LOD为0.8 wt% (Harris等人，2004[1])，这表明光纤激光LIBS能够在大气条件下精确测定固态材料中的氮，而不需要额外的设备，如真空或气体净化系统。

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引用次数: 0

Casting-solidification preparation combined with substitution-dilution algorithm for accurate EDXRF analysis of silicate rocks 铸造-凝固制备结合取代-稀释算法对硅酸盐岩石进行精确的EDXRF分析

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-11-06 DOI: 10.1016/j.sab.2025.107385

Bo Wang , Wenbao Jia , Xiaoran Chen , Kai Zeng , Zhichao Zhang , Qing Shan , Yongsheng Ling

The accurate energy-dispersive X-ray fluorescence (EDXRF) analysis of high-silica silicate rocks is notoriously challenging due to their poor cohesiveness, which prevents the formation of stable pressed pellets, and the scarcity of matrix-matched reference materials. To address these limitations, this study introduces a novel integrated methodology that synergistically combines an innovative casting-solidification preparation technique with a robust substitution-dilution quantification algorithm. The preparation method employs metallographic resin to embed powdered samples, effectively overcoming cohesion issues and producing highly homogeneous (RSD < 4 %) and reproducible (RSD < 5.19 %) pellets. The mathematical algorithm leverages a fundamental hyperbolic relationship between the X-ray intensity and the substitution factor, enabling highly accurate quantification of major oxides (SiO₂, Al₂O₃, K₂O, CaO) using only a single standard reference material—thereby eliminating the critical dependency on multiple matrix-matched standards. Validation against a range of certified reference materials demonstrated excellent accuracy, with relative errors for major oxides ranging from 1.53 % to 6.72 % . A comprehensive uncertainty evaluation confirmed expanded uncertainties below 7.4 % at a 95 % confidence level. This integrated approach establishes a new, cost-effective, and reliable paradigm for EDXRF analysis of complex silicate materials.

高硅硅酸盐岩石的精确能量色散x射线荧光（EDXRF）分析是出了名的具有挑战性，因为它们的凝聚力差，这阻碍了稳定压球的形成，并且缺乏基质匹配的参考物质。为了解决这些限制，本研究引入了一种新的集成方法，该方法将创新的铸造凝固制备技术与强大的替代稀释量化算法协同结合。制备方法采用金相树脂包埋粉末样品，有效地克服了粘聚问题，生产出高度均匀（RSD < 4%）和可重复性（RSD < 5.19%）的颗粒。数学算法利用了x射线强度和替代因子之间的基本双曲关系，仅使用单一标准参考物质就可以高度精确地定量主要氧化物（SiO2, Al2O3, K2O, CaO），从而消除了对多个矩阵匹配标准的关键依赖。对一系列认证标准物质的验证证明了极好的准确性，主要氧化物的相对误差范围为1.53%至6.72%。综合不确定性评估确认在95%置信水平下扩大不确定性低于7.4%。这种综合方法为复杂硅酸盐材料的EDXRF分析建立了一种新的、经济有效的、可靠的范例。

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引用次数: 0

Ag NP-coated filter paper as a nanoparticle-enhanced laser-induced breakdown spectroscopy substrate for quantitative detection of potassium Ag - np涂布滤纸作为纳米粒子增强激光诱导击穿光谱底物用于钾的定量检测

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-11-06 DOI: 10.1016/j.sab.2025.107386

Xinxin Zhang , Yumeng Yuan , Zihao Guo , Xue Chen , Xiaohui Li

Accurate monitoring of serum potassium (K) levels is essential for clinical diagnostics due to their vital roles in maintaining physiological functions. Although laser-induced breakdown spectroscopy (LIBS) enables rapid elemental analysis, its limited sensitivity and precision restrict its effectiveness in quantifying K in complex biological samples. This study explores the application of silver nanoparticle-coated filter paper (Ag NPs paper) as a substrate for nanoparticle-enhanced LIBS (NELIBS) to improve the quantitative detection of K. First, the preparation process of the Ag NPs paper substrate was systematically optimized. The optimal K detection signal was obtained with the Ag NPs paper substrate treated with 1.5 mol/L NaCl and colloidal Ag NPs at neutral pH. Then, the optimized Ag NPs paper was employed for quantitative determination of K in potassium-chloride (KCl) aqueous solution and fetal bovine serum (FBS), including hypokalemia, hyperkalemia, and normal potassium levels. Under these conditions, the limit of detection (LoD) of NELIBS for K was lower than that of normal LIBS, decreasing from 2.29 mmol/L (89.3 mg/L) to 0.81 mmol/L (31.6 mg/L) in KCl aqueous solution and from 0.96 mmol/L (37.4 mg/L) to 0.32 mmol/L (12.5 mg/L) in FBS, respectively. It also enabled reliable discrimination of concentration changes as small as 0.5 mmol/L. These findings highlight the feasibility of NELIBS for sensitive and accurate detection of electrolyte elements in complex biological samples, offering promising prospects for clinical diagnostics.

准确监测血清钾(K)水平对临床诊断至关重要，因为它们在维持生理功能中起着至关重要的作用。虽然激光诱导击穿光谱（LIBS）能够快速进行元素分析，但其有限的灵敏度和精度限制了其在复杂生物样品中定量K的有效性。本研究探索将纳米银涂层滤纸（Ag NPs纸）作为纳米颗粒增强LIBS （NELIBS）的衬底，以提高k的定量检测。首先，系统优化了Ag NPs纸衬底的制备工艺。将银NPs纸底物经1.5 mol/L NaCl和中性ph的胶体银NPs处理后获得最佳的钾检测信号，并将优化后的银NPs纸用于定量测定氯化钾（KCl）水溶液和胎牛血清（FBS）中的钾，包括低钾血症、高钾血症和正常钾水平。在此条件下，NELIBS对K的检出限（LoD）低于正常LIBS，在KCl水溶液中从2.29 mmol/L （89.3 mg/L）降至0.81 mmol/L (31.6 mg/L)，在FBS中从0.96 mmol/L （37.4 mg/L）降至0.32 mmol/L （12.5 mg/L）。它还可以可靠地辨别小至0.5 mmol/L的浓度变化。这些发现突出了NELIBS在复杂生物样品中灵敏、准确检测电解质元素的可行性，为临床诊断提供了广阔的前景。

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引用次数: 0

Study on the influence of molecular structures and laser parameters on the laser-induced breakdown spectroscopy features of CN and C2 in plastic 分子结构和激光参数对塑料中CN和C2激光诱导击穿光谱特性影响的研究

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-11-04 DOI: 10.1016/j.sab.2025.107380

Hao Zhou , Yongyue Zheng , Xiangjun Xu , Geer. Teng , Zhifang Zhao , Mengyu Bao , Bingheng Lu , Leifu Wang , Yuge Liu , Shuai Xu , Q.Q. Wang

This paper investigates the laser-induced breakdown spectroscopy (LIBS) emission characteristics of CN(378.3–379.1 nm) and C₂(504.2–519.0 nm) in four representative types of polymer synthetic materials, examining their evolution pathways and the influence of different molecular structures to establish correlations linking CN emission with carbon atoms, and C₂ with CC bonds. The impacts of laser wavelength (from visible to near infrared) and pulse duration (from nanoseconds to femtoseconds) on these emissions is emphatically explored. Findings show that the specificity of CN and C₂ molecular bands serves as a robust basis for organic material analysis. Using a 532 nm Nd:YAG laser can boost the emission intensity of CN, C₂, due to its higher single-photon energy than that of fundamental frequency. Furthermore, a fs-laser, with a pulse duration shorter than the lattice vibration time, ensures excellent signal reproducibility. The specific formation mechanism and influencing factors of laser-induced molecular fragmentation at different timescales from nanoseconds to femtoseconds was investigated. The experimental results show that the plastic classification accuracy of ns-LIBS exceeded 90 %, outperforming that of fs-LIBS. When using the CN and C₂ molecular bands from ns-LIBS (532 nm) as input, the SVM model achieved the highest accuracy of 96.35 %. On the other hand, fs-LIBS demonstrated significantly greater robustness, with its highest accuracy of 50.00 % substantially exceeding the 30.50 % obtained by ns-LIBS. Experimental results are expected to advance LIBS techniques for partial materials identification, with implications for environmental monitoring, waste management, and resource recovery, highlighting the potential of LIBS in analyzing plastics and promoting sustainability.

本文研究了四种典型高分子合成材料中CN（378.3 ~ 379.1 nm）和C2（504.2 ~ 519.0 nm）的激光诱导击穿光谱（LIBS）发射特性，考察了它们的演化途径和不同分子结构的影响，建立了CN发射与碳原子、C2与CC键之间的关联。重点探讨了激光波长（从可见光到近红外）和脉冲持续时间（从纳秒到飞秒）对这些发射的影响。结果表明，CN和C2分子带的特异性为有机物质分析提供了坚实的基础。使用532 nm Nd:YAG激光器可以提高CN， C2的发射强度，因为它的单光子能量高于基频。此外，脉冲持续时间短于晶格振动时间的fs激光器确保了良好的信号再现性。研究了从纳秒到飞秒不同时间尺度上激光诱导分子断裂的具体形成机制和影响因素。实验结果表明，ns-LIBS的塑料分类准确率超过90%，优于fs-LIBS。当使用ns-LIBS （532 nm）的CN和C2分子带作为输入时，SVM模型的准确率最高，达到96.35%。另一方面，fs-LIBS表现出更强的鲁棒性，其最高准确率为50.00%，大大超过ns-LIBS的30.50%。实验结果有望推动LIBS技术在部分材料识别方面的发展，对环境监测、废物管理和资源回收具有重要意义，突出了LIBS在分析塑料和促进可持续性方面的潜力。

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引用次数: 0

Drop-spark discharge atomic emission determination of silver with a liquid anode sample introduction: Analytical possibilities and unusual matrix interferences 液滴火花放电原子发射法测定银的液体阳极样品简介：分析的可能性和不寻常的基质干扰

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-11-04 DOI: 10.1016/j.sab.2025.107382

Andrey Zhirkov, Vladimir Yagov

The metrological characteristics of drop-spark optical emission spectrometry determination of Ag with anode sampling were established. The influence of a wide range of organic and inorganic compounds has been studied. The application of 0.15 M ammonia background solution is shown to provide maximum analysis sensitivity and increases possible range of sample types due to tolerance to chloride. Under these optimal conditions, the detection limit is 1 ppb, and the linear calibration range is 3 orders of magnitude. The developed procedure was successfully applied in the Ag determination in copper electrical cable (9.5 ppm) and antiquarian copper coin (0.14% wt.).

建立了阳极取样法滴火花光学发射光谱法测定银的计量特性。广泛的有机和无机化合物的影响已被研究。0.15 M氨本底溶液的应用表明，由于对氯化物的耐受性，可以提供最大的分析灵敏度，并增加样品类型的可能范围。在此最佳条件下，检测限为1 ppb，线性校准范围为3个数量级。该方法成功地应用于铜电缆（9.5 ppm）和古铜币（0.14% wt.）中银的测定。

引用次数: 0

State-of-the-art MC-ICP-MS methodology for precise plutonium isotope ratios 最先进的MC-ICP-MS方法用于精确的钚同位素比率

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-11-02 DOI: 10.1016/j.sab.2025.107375

SiQi Guo, Wei Wang, ZhiMing Li, Jiang Xu, RuiYang Xi, YaLong Wang, XiuFang Zhai, Liang Zhang, Lei Feng, XinYi Zhang, Mao Fan

This work details technical advancements in multi-collector inductively coupled plasma mass spectrometry (MC–ICP–MS) for high-precision plutonium (Pu) isotope ratio analysis. Uranium (U) and Pu isotopes have been proven to exhibit similar mass fractionation effects, as measured using MC–ICP–MS, within analytical uncertainty. Herein, ²³³U-²³⁶U double spike method with IRMM3636 was developed to correct the mass fractionation while measuring Pu isotope measurement, achieving an RSD% of 0.0029 % for Pu isotope ratios at 10⁻² level. This method was the first one to precisely measure low-abundance isotopes such as ²⁴¹Pu and ²⁴²Pu via combining Faraday cup (10¹³Ω amplifier) and secondary electron multiplier detector configuration. At trace levels (ng), long-term RSDs of ²³⁹Pu at a laboratory working standard reached 0.019 % (²⁴¹Pu/²³⁹Pu) and 0.046 % (²⁴²Pu/²³⁹Pu) near the 10⁻⁴ level, demonstrating exceptionally high precision in the isotope ratio analysis and representing the highest precision reported to date for these ratios. This state-of-the-art method maintained high sample throughput while delivering exceptional accuracy. Its robustness was confirmed through successful application to Pu isotope analysis in irradiated nuclear fuel samples, highlighting its broad applicability.

本文详细介绍了用于高精度钚（Pu）同位素比分析的多收集器电感耦合等离子体质谱（MC-ICP-MS）的技术进展。在分析不确定度范围内，使用MC-ICP-MS测量的铀(U)和Pu同位素已被证明具有类似的质量分馏效应。在此基础上，利用IRMM3636建立了233U-236U双尖峰法，对10−2水平下的Pu同位素比进行质量分选校正，RSD%为0.0029%。该方法首次通过法拉第杯（1013Ω放大器）和二次电子倍增探测器的组合，对241Pu和242Pu等低丰度同位素进行了精确测量。在痕量水平（ng）下，实验室工作标准下239Pu的长期rsd在10−4水平附近达到0.019% （241Pu/239Pu）和0.046% (242Pu/239Pu)，显示出异常高的同位素比率分析精度，是迄今为止报道的这些比率的最高精度。这种最先进的方法保持高样品吞吐量，同时提供卓越的准确性。通过对辐照核燃料样品中Pu同位素分析的成功应用，证实了该方法的稳健性，突出了其广泛的适用性。

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引用次数: 0

Spatially resolved studies of laser-induced plasma by a two-line fluorescence thermometry 用双线荧光测温法研究激光诱导等离子体的空间分辨

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-10-31 DOI: 10.1016/j.sab.2025.107381

Babken G. Beglaryan, Aleksandr S. Zakuskin, Andrey M. Popov, Timur A. Labutin

A laser-induced fluorescence (LIF) thermometry technique was developed for spatially resolved diagnostics of laser-induced plasma (LIP). The method adapts the two-line fluorescence approach by using two independent three-level excitation schemes of Ti I. Analysis of excitation–relaxation kinetics shows that, under typical experimental conditions, absorption and stimulated emission rates exceed spontaneous decay by several orders of magnitude, enabling rapid fluorescence saturation. An analytical expression was derived that relates the ratio of saturated fluorescence intensities from two schemes to the plasma temperature. Two Ti I schemes, a³P₂ → x³P°₁ → a³P₀ (Scheme A) and z⁵G°₅ → e⁵G₆ → z⁵F°₅ (Scheme B), were implemented, producing stable signals with substantial enhancement over spontaneous emission at 405.501 and 403.051 nm, respectively. Using these schemes, a two-dimensional temperature distribution of the central plasma cross-section was obtained with high spatial resolution. The temperature near the plasma axis (radius of 2 mm) was ≈4000 K, increasing to 6000–8000 K in the periphery, forming a pronounced radial gradient. The occurrence of this high-temperature zone coincides with regions influenced by shock-wave propagation, suggesting two possible mechanisms: direct shock-wave heating and the transport of excited particles with the wave front.

建立了用于激光诱导等离子体（LIP）空间分辨诊断的激光诱导荧光（LIF）测温技术。该方法采用两种独立的三能级激发方案，采用两线荧光法。激发-弛豫动力学分析表明，在典型的实验条件下，吸收和受激发射速率超过自发衰减数个数量级，实现了荧光快速饱和。导出了两种方案的饱和荧光强度与等离子体温度之比的解析表达式。采用了a3P2→x3P°1→a3P0（方案A）和z5G°5→e5G6→z5F°5（方案B）两种Ti I方案，分别在405.501和403.051 nm处产生稳定的信号，自发发射增强明显。利用这些格式，获得了高空间分辨率的等离子体中心截面的二维温度分布。等离子体轴（半径2 mm）附近温度≈4000 K，外围温度增加到6000 ~ 8000 K，形成明显的径向梯度。该高温区的出现与激波传播的影响区域一致，提示两种可能的机制：激波直接加热和激波前的激振粒子输运。

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引用次数: 0

Overcoming matrix effects on the determination of phosphorus concentration in sewage sludge ash using laser-induced breakdown spectroscopy hand-held instrumentation 激光诱导击穿光谱手持式仪器测定污水污泥灰中磷浓度克服基质效应

IF 3.8 2区化学 Q1 SPECTROSCOPY

Spectrochimica Acta Part B: Atomic Spectroscopy

Pub Date : 2025-10-29 DOI: 10.1016/j.sab.2025.107377

Mattia Massa , Elisa Galli , Alessandra Zanoletti , Annalisa Zacco , Silvana De Iuliis , Laura Eleonora Depero , Vincenzo Palleschi , Laura Borgese , Elza Bontempi

Sewage sludge ash (SSA), derived from the incineration of wastewater treatment sludge, typically contains phosphorus concentrations ranging from 4 % to 12 % by weight. This significant P content makes SSA a promising secondary resource, particularly for applications such as fertilizer production. In this study, we explore the feasibility of using handheld Laser-Induced Breakdown Spectroscopy (LIBS) for the rapid and direct determination of phosphorus content in SSA samples. The proposed method enables rapid and accurate quantification of phosphorus with minimal sample preparation and demonstrates strong resilience to matrix effects, which often compromise the reliability of conventional LIBS analysis.

The approach is based on a Convolutional Neural Network (CNN), designed to produce a single calibration model capable of addressing the wide variability in phosphorus concentration typically observed in SSA samples. The innovative aspect of this work is the complete separation of the training stage of the CNN, which is done using simple synthetic reference samples, from the validation, which involves actual SSA samples collected from a waste-to-energy power plant, previously characterized using standard laboratory methods. This procedure allows to select, among the many spectral features that can be used for modelling the training set, only the ones that are proven to effectively work for the determination of phosphorous concentration in the SSA samples, which have a much more complex composition with respect to the synthetic training samples.

In addition to presenting this novel methodology, the study also includes a discussion of alternative approaches reported in the literature for matrix-independent quantitative LIBS analysis of phosphorus. This comparative overview highlights the advantages of the proposed method for in-situ analysis of SSA.

污水污泥灰（SSA），来源于废水处理污泥的焚烧，通常含有磷浓度从4%到12%的重量。这种显著的P含量使SSA成为一种有前途的二次资源，特别是在肥料生产等应用中。在本研究中，我们探索了手持式激光诱导击穿光谱（LIBS）快速直接测定SSA样品中磷含量的可行性。所提出的方法能够快速准确地定量磷，只需最少的样品制备，并且对基质效应具有很强的弹性，这通常会损害传统LIBS分析的可靠性。该方法基于卷积神经网络（CNN），旨在产生一个单一的校准模型，能够解决在SSA样品中通常观察到的磷浓度的广泛变化。这项工作的创新之处在于将CNN的训练阶段（使用简单的合成参考样本）与验证阶段（涉及从废物发电厂收集的实际SSA样本，之前使用标准实验室方法进行表征）完全分离。该程序允许在许多可用于训练集建模的光谱特征中选择，只有那些被证明有效地用于测定SSA样品中磷浓度的特征，这些样品的组成比合成训练样品复杂得多。除了提出这种新颖的方法外，该研究还包括对文献中报道的用于不依赖基质的磷定量LIBS分析的替代方法的讨论。这一对比概述突出了该方法在SSA原位分析中的优势。

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