Editor in Chief:
Prof. Xian-Hua Li

Executive Editor:
Prof. Wei Guo

Associate Editors:
Prof. Michael Dürr
Prof. Wei Hang
Prof. Zhaochu Hu

Print ISSN:0195-5373
Online ISSN: 2708-521X
2022 SCI IF: 3.4 (JCR, Q1)

The ATOMIC SPECTROSCOPY is a peer-reviewed international journal started in 1962 by Dr. Walter Slavin. In November 2019, its ownership was transferred to Atomic Spectroscopy Press Limited (ASPL), Hongkong, P.R. China. It is intended for the rapid publication of Articles, Review/Mini-review, or Letters/Communications in the fields of elements, elemental speciation, and elemental isotopic analysis by XRF, AAS, AFS, ICP-OES, ICP-MS, GD-MS/OES, TIMS, SIMS, AMS, LIBS, AMS, NAA, INAA, various microanalysis techniques, and related sample preparation techniques. Manuscripts dealing with (i) instrumentation & fundamentals, (ii) methodology development & applications, and (iii) standard reference materials (SRMs) development can be submitted for publication.

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Quantitative Determination of Cd Using Energy Dispersion XRF Based on Gaussian Mixture Clustering-Multilevel Model Recalibration

Zhi Zhang, Yunbing Gao*, Yanan Zhao, Xiaoyang Liu, Xue Li, Xuefei Mao, Yuchun Pan, Wenbin Sun, Xiande Zhao

DOI: 10.46770/AS.2024.038

[Abstract] (0) [PDF 5.30 M] (0)

Abstract:
The analysis accuracy of energy dispersion X-ray fluorescence spectrometry (XRF) for detecting heavy metal in agricultural soils is severely depending on complex matrix effect, thereby posing a challenge in fast and precise monitoring soil contamination. To calibrate the XRF detection, a Gaussian mixture clustering-multilevel model (GMC-MLM) was proposed to enhance XRF accuracy for Cd in agricultural soils. Compared with other models such as multiple linear regression (MLR), random forest regression (RF), and support vector machine regression (SVMR), the GMC-MLM effectively disentangled the nested distribution of XRF detection errors. The correlation coefficient between the XRF detection results and ICP-MS test results for the corrected samples can reach 0.9085, with 74% of the corrected samples having a relative error of less than 30%. Notably, according to the GMC-MLM correction method, a knowledge base for localizing corrections in XRF detection has been constructed. When the number of knowledge base sample points is 50, the RMSE (Root Mean Squared Error), and REM (Relative Error of Mean) are 0.7347, 3.7014%, respectively. It can be observed that the model has good extrapolation capability, and with the increase in the number of knowledge base sample points, the correction effect based on the knowledge base gradually stabilizes. This knowledge base-based GMC-MLM calibration method not only can be embedded into XRF detection instruments to correct XRF detection results in different regions of China but also provides theoretical support for the establishment of a nationwide soil sample knowledge base.

A Review of Development in the Research of Self-Absorption on Laser-Induced Breakdown Spectroscopy

Yun Tang*, Ping Liao, Kai Yang, Zhenlin Hu, Deng Zhang, Zeeng Yang, Sheng Wang, Enxin Guo, Nan Zhao*

DOI: 10.46770/AS.2024.041

[Abstract] (1) [PDF 2.49 M] (9)

Abstract:
Laser-induced breakdown spectroscopy (LIBS) has been successfully applied to various fields since its inception in the late twenty century. However, there are still challenges to enhance its performance in analytical experiments. These challenges include three major challenges: matrix effect, spectral interference, and self-absorption effect. This review specifically focuses on investigating the self-absorption effect, which disrupts the linear relationship between spectral line intensity and element concentration, thus affecting the accuracy and sensitivity of LIBS analysis. The review explores different approaches to evaluate the extent of self-absorption, considering the evolutionary mechanism of this effect. Additionally, various methods for correcting spectra have been proposed, showing potential in significantly reducing self-absorption. Notably, the review emphasizes proactive measures to create non-self-absorbed conditions as the most effective approach to mitigate the self-absorption effect. Finally, the review presents a schematic description of exploiting self-absorption and highlights its promising prospects for future applications of LIBS.

Covalent Targeting Drug Mediated Specific Lanthanide Tagging Towards In Situ Bruton's Tyrosine Kinase Quantification Using ICP-MS

Ruxue Hou, Yuxin Gu, Yang Zhao, Xinyue Zhao, Limin Yang, Xiaowen Yan*, Qiuquan Wang

DOI: 10.46770/AS.2024.078

[Abstract] (2) [PDF 7.17 M] (9) [Supporting Information]

Abstract:
Bruton's tyrosine kinase (BTK) is an important target for the treatment of multiple B-cell malignancies and autoimmune diseases. Development of approach that can accurately detect the expression and activity of BTK in live cells is of great significance for the diagnosis and treatment of cancer. In this study, we exploited ibrutinib, an FDA approved covalent targeting drug, for specific lanthanide labeling and quantification of BTK in live Ramos Burkitt’s lymphoma cells. A Europium (Eu) labeled ibrutinib probe (Ibt-DOTA-Eu) probe was first synthesized by conjugation of ibrutinib with DOTA, a chelator which can form highly stable complexes with lanthanides. We found that Ibt-DOTA-Eu is difficult to penetrate the cell membrane for in situ BTK labeling. To overcome this problem, we designed and synthesized an azide-modified ibrutinib probe (Ibt-N3) that can easily pass through the cell membrane, label BTK in live cells, and then realize DBCO-DOTA-Eu labeling through strain-promoted azide-alkyne cycloaddition (SPAAC) reaction. The Eu-labeled BTK in Ramos cells is quantified to be 61.28 ng/106 cells by using 153Eu-species-nonspecific-isotope-dilution ICP-MS coupled with HPLC. To our knowledge, this is the first study quantifying a disease-relevant kinase in live cells by using covalent targeting drug mediated lanthanide labeling and ICP-MS, which will prompt the application of ICP-MS in disease diagnosis and drug development in the future.

Data Processing Strategies for the Improved Analysis of Solder by Electrothermal Vaporization (ETV) Coupled to ICP-OES

Kate Moghadam, Diane Beauchemin*

DOI: 10.46770/AS.2024.032

[Abstract] (1) [PDF 1.01 M] (8) [Supporting Information]

Abstract:
Applications of electrothermal vaporization coupled to inductively coupled plasma optical emission spectrometry (ETV-ICPOES) may require offline, and often manual, processing for data compilation and optimization. Techniques for data processing have traditionally applied internal standardization and some form of correction (e.g., blank subtraction) to compensate for positive bias from the background. However, a blank may not always be easily obtained in applications of solid-sampling research, and in some cases, degrade detection limits and signal integrations. In this work, several data processing techniques are evaluated, after point-by-point internal standardization with an Ar emission line, for the sensitive and accurate analysis of solder by ETV-ICPOES: peak area with average blank subtraction from empty graphite boats (Technique A), peak area with integrated background correction (Technique B), and peak height with averaged background correction (Technique C). Despite being the simplest to implement, subtracting the average background signal from the height of the peak produced during the vaporization step, i.e., Technique C, systematically yields the lowest detection limits without compromise in accuracy or precision.

New Potential Apatite Reference Materials for Direct Sr Isotope Analysis by LA-MC-ICP-MS

Jing Wang*, Ben-Xun Su, Shi-Ying Wang, Wen-Jun Li, Bing-Yu Gao, Wen-Gang Liu

DOI: 10.46770/AS.2024.034

[Abstract] (2) [PDF 5.09 M] (10) [Supporting Information]

Abstract:
High-quality Sr isotope data are critically dependent on the quality of reference materials that are used for instrumental calibration and data monitoring during LA-MC-ICP-MS analysis. Two natural apatite samples (SL-7 and SM139-1) were investigated here to test their suitability as in-situ Sr isotopic analysis reference materials. Major and trace element analyses by EPMA and LA-ICP-MS showed that apatites were all characterized by high Cl (1.80~2.46 wt%), high Sr contents (> 3752 μg g-1) and extremely low Rb/Sr ratios. A total of 120 and 126 LA-MC-ICP-MS analyses for SL-7 and SM139-1 apatite showed consistent and homogeneous Sr isotopic compositions with average 87Sr/86Sr ratio of 0.70521 ± 0.00016 (2SD, n = 120) and 0.70509 ± 0.00015 (2SD, n = 126), respectively, which were in good agreement with solution-based data determined by TIMS or SN-MC-ICP-MS (0.705219 ± 0.000019 (2SD, n = 13) and 0.705114 ± 0.000041 (2SD, n = 13), respectively), suggesting that SL-7 and SM139-1 apatites can be used as potential reference materials for microbeam Sr isotopic analysis.

Micro-XRF Mapping Elucidates the Taphonomy of Two Early Cretaceous Paravian Fossils from Western Liaoning, China

Yichuan Liu, Qiang Ji*, Xuri Wang*, Jie Yang, Jingmai K. O’Connor, Bin Guo, Tianlong Ren, Tingting Yin, Yingbo Wang

DOI: 10.46770/AS.2024.033

[Abstract] (5) [PDF 6.64 M] (58) [Supporting Information]

Abstract:
Paraves is the taxonomic group that includes Dromaeosauridae, Troodontidae and Avialae, and thus records the origin of birds, the evolution of pennaceous feathers, and their exaptation for flight. Non-destructive micro-X-ray fluorescence (micro-XRF) imaging technology was utilized to analyze two paravian fossil specimens, one referrable to the Microraptorinae (Dromaeosauridae) and the other to the Yanornithidae (Avialae). Both fossils are from the Lower Cretaceous Aptian Jiufotang Formation, a Lagerst?tte that records the youngest stage of the famous Jehol Biota in western Liaoning, China. The analyses show that the bones preserve high amounts of Calcium (Ca), Phosphorus (P), and Sulfur (S), with significant amounts of heavy elements such as Strontium (Sr) and Yttrium (Y) which may be related to biological apatite. The preserved feathers show high amounts of Cuprum (Cu), Nickel (Ni) and Titanium (Ti). The claw sheaths exhibit high levels of P and Ca, which suggests they were preserved through phosphatization. Notably, large amounts of Ferrum (Fe) occur at the intraskeletal joints in both specimens and in the trunk of the microraptorine. Further analyses indicate that the enrichment of Fe may be related to the presence of pyrite. The distribution of Fe indicates precipitation of this element was a postburial taphonomic process. This micro-XRF data reveals the distribution of elements in different tissue types in these two paravian fossils and provides information for reconstructing the taphonomic processes responsible for exceptional preservation in paravian fossils in the Jiufotang Formation.

In Situ Analysis of Low-Li-Be Samples by Secondary Ion Mass Spectrometry

Qing Yang, Zexian Cui, Xiao-Ping Xia*, Chun-Kit Lai, Wan-Feng Zhang, Yan-Qiang Zhang

DOI: 10.46770/AS.2024.037

[Abstract] (16) [PDF 3.95 M] (152) [Supporting Information]

Abstract:
Lithium and beryllium are strategic key metals, which are indispensable in emerging information technology and green energy industries. They are also powerful tracers in a wide range of geological processes, notably those related to deep-earth elemental cycling and ore deposition. Secondary ion mass spectrometry (SIMS) analysis has the advantages of in situ, high spatial resolution and almost non-destruction. Here, we present a modified SIMS procedure to measure the Li-Be contents in eight well characterized Li-Be-poor glass samples (Li = 3?43 ppm, Be = 0.034?46 ppm) and one new synthetic glass with purity (considered as Li and Be free) to evaluate the analytical precision, accuracy and limit of detection (LOD). For lithium, the internal precision is better than 0.42% (1SE), and the spot-to-spot reproducibility is mostly better than 2.71% (RSD). For beryllium, the internal precision is better than 0.93% (1SE), and the spot-to-spot reproducibility is better than 4.68% (RSD). For the Li and Be contents, the difference between the calibrated SIMS elemental contents and the recommended value is generally below 5.1% and 7.9%, respectively. The LOD is ~0.04 ppb for Li and ~0.01 ppb for Be. All these demonstrate the improved performance of this analytical technique and its reliability for measurement of low-Li-Be samples. The findings contribute to our understanding of the Li-Be distribution and behavior in geological materials, and provide implications to mineral exploration and environmental studies.

Optimized Preconcentration Method Using Ionic Liquid Ferrofluid for Ultra-Trace Determination of Cr(VI) in Drinking Water by Inductively Coupled Plasma Mass Spectrometry

Yam Nath Gotame, Diane Beauchemin*

DOI: 10.46770/AS.2024.019

[Abstract] (14) [PDF 3.16 M] (142) [Supporting Information]

Abstract:
Herein, a simple and fast method was developed for efficient preconcentration of anionic Cr(VI) in drinking water using, for the first time, an ionic liquid ferrofluid (IL-FF) for its interference-free ultra-trace (ng L-1) determination by inductively coupled plasma mass spectrometry. To improve the selectivity of the IL-FF, the surface of commercially available Fe3O4 magnetic nanoparticles (MNPs) was coated with silica and functionalized with L-cysteine (SCMNPs-Cys). The structural features of the SCMNPs-Cys were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, and X-ray diffraction. Experimental conditions, including the sample solution pH, elution time, and eluent concentration, were optimized. A 20-fold enrichment factor resulted in a limit of detection of 3 ng L-1. The applicability of the method was confirmed by the analysis of Cr(VI) in different water samples with recoveries of 84-91% (n=3).

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Atom Probe Tomography Reveals Nano-scale Organic Remaining in Conodont

Fan Gao, Jing Xue, Xian-Hua Li, Rong Hu*, Qiu-Li Li*

2024,45(1),1-8,

DOI: 10.46770/AS.2024.026

[Abstract] (32) [PDF 8.89 M] (475) [Supporting Information]

Abstract:
Distinguishing biomineralized minerals from inorganic minerals has been a longstanding challenge. The organic matter within biomineralized minerals constitutes compelling evidence that sets them apart from inorganic minerals. However, for small samples that have undergone degradation and diagenetic alteration, routine analytical technologies have difficulties in identifying internal residual organic signals. Atom Probe Tomography, as the highest-spatial-resolution microanalytical technique, facilitates the study of elements spatial distribution and nano-scale structures, holding significant potential for applications in biogeochemistry. In this study, Atom Probe Tomography has been applied to fossil samples for the first time, comparing inorganic Durango apatite with fossil conodont. This research discovered residual organic components within conodont, manifesting in the form of nano-scale particles coupled with high carbon and nitrogen concentrations. This signal is promising for differentiating between biominerals and inorganic minerals, which is greatly potential for identifying nano-scale biosignatures in ancient samples.

A Glimpse into the Nature of Particles Created During Pulsed Laser Ablation of Arsenic Compounds in Ambient Gases

Zdenka ?lejkovec, Johannes T. van Elteren*, Melanie Bergmann, Walter Goessler*

2024(1),9-14,

DOI: 10.46770/AS.2023.305

[Abstract] (24) [PDF 1.15 M] (332) [Supporting Information]

Abstract:
The composition of particles resulting from pulsed laser ablation is not well understood, although it is anticipated that molecules from the ablated material undergo varying degrees of breakdown, depending on factors such as laser wavelength, energy, pulse width, matrix properties, and gas atmosphere. As reliable arsenic characterization and speciation techniques are available, a fundamental study was undertaken to shed light on the behavior of arsenic compounds (arsenic pentoxide, dimethylarsenic acid, and arsenobetaine within a cellulose matrix, along with pure elemental arsenic), using a pulsed 213 nm Nd:YAG laser and ablation in different gas atmospheres (He, Ar/CO2 [99/1 %], Ar/O2 [80/20 %], and O2) at atmospheric pressure. The generated arsenic, collected in aerosol form on inline syringe filters (0.2 μm), was subjected to sequential dissolution, yielding water-soluble, HCl-soluble, and insoluble fractions. The water-soluble fraction was analyzed for arsenic species using chromatographic techniques in combination with element-specific detection. The analysis revealed that extremely complex processes take place during laser ablation, not only (partially) stripping organoarsenic species from their methyl groups and lowering the valence state, but also creating conditions for the synthesis of methylated arsenic species from arsenic pentoxide and generating more or less soluble nano/micro/macro particles for all arsenic compounds. These findings contribute to a more nuanced understanding of the multifaceted photochemical transformations that may occur during laser ablation of molecules.

A Spectral Optimization Method to Enhance Handheld LIBS for T91 Aging Grade Classification Using Lorentzian Profile and Kalman Filter

Zihan Shang, Meirong Dong*, Weiye Lu, Junbin Cai, Kaijie Bai, Feiqiang Tang, Zhichun Li, Shunchun Yao, Jidong Lu

2024,45(1),15-25,

DOI: 10.46770/AS.2023.297

[Abstract] (33) [PDF 9.50 M] (344)

Abstract:
The handheld laser-induced breakdown spectroscopy (LIBS) device has been developed to evaluate the aging grade of T91 heat-resistant steel. However, the reduced size of the device could potentially affect the accuracy of the measurement. To overcome this challenge, a novel spectral preprocessing approach that combines Lorentzian fitting correction and extended Kalman filter with support vector machine (SVM) is proposed in this work to enable the reliable evaluation of T91 aging grade by a handheld LIBS. The spectral features of T91 samples were measured and revealed that the obtained spectral line broadening is mainly due to Stark broadening. Consequently, the independent spectral peaks in the spectra can be corrected with Lorentzian function to obtain more comprehensive spectral information. Afterwards, the extended Kalman filter is introduced to further correct the measured spectral data, diminishing the fluctuation in the spectral signal and the device noise during the measurement. The results show that the accuracy of the T91 aging grade classification model based on the new preprocessing method can achieve 94 %. This surpasses the accuracy of the models developed with standard normal variation (SNV) and multi-scatter calibration (MSC) preprocessing methods. The proposed method improves the accuracy of handheld LIBS for T91 aging grade classification and provides a new insight into improving the quality of LIBS spectral data.

Thin Layer Method for LA-ICP-MS Analysis of Trace Elements Concentrates of Germanium Dioxide

Nickolay S. Medvedev*, Valeriya D. Kurbatova, Tatiana Ya. Guselnikova, Anatoly I. Saprykin

2024,45(1),26-32,

DOI: 10.46770/AS.2023.256

[Abstract] (20) [PDF 1.76 M] (311)

Abstract:
A combination of trace elements preconcentration and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is proposed for the analysis of high purity substances. The analytical figures of merit of this combination were evaluated using high purity germanium dioxide as an example. Trace elements were preconcentrated by germanium volatization in the form of germanium tetrachloride from sample solutions. The trace elements concentrate was evaporated to dryness on the surface of a high-purity silicon substrate and analyzed by LA-ICP-MS. Indium was used as an internal standard to obtain quantitative data. Limits of detection (LODs) for 47 trace elements are in the range from 0.3 to 300 ppt wt (0.3 to 300 pg g-1). The obtained LODs are 10-100 times lower compared to ICP-MS analysis of germanium with preconcentration of trace elements. The accuracy of results was confirmed by comparing with results obtained by the traditional ICP-MS analysis of the trace elements concentrates and by the “spike” experiments.

Determination of Sb Isotope Ratios in Stibnite Using fs-LA-MC-ICP-MS and Two Potential Reference Materials Study

Wei Wang, Chao Li*, Bo Zu, Jihao Zhang, Pengyue Yu, Hongyu Ren, Xinwei Li, Limin Zhou, Wenjun Qu

2024,45(1),33-43,

DOI: 10.46770/AS.2024.013

[Abstract] (20) [PDF 11.52 M] (352) [Supporting Information]

Abstract:
This study demonstrates an analytical method for the high spatial resolution (20 μm) and high-precision determination of antimony (Sb) isotope composition in stibnite, using femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (fs-LA-MC-ICP-MS). The potential matrix effect-inducing elements in Sb isotope composition measurements exhibit extremely low concentrations in two newly introduced natural stibnite reference materials, DC and BJS, rendering their impact virtually negligible during fs-LA-MC-ICP-MS analysis. Through reciprocal correction of DC and BJS, consistent results were achieved, aligning with those obtained by SN-MC-ICP-MS, indicating an absence of discernible matrix effects between the two samples. A comprehensive assessment was conducted to evaluate the contribution of the Sn standard solution to enhance the external precision of measurements. The 2SD of δ123Sb mean values increased by 0.02‰ to 0.04‰. Adjusting the laser ablation spot size (5μm-80μm) to control signal intensity, we investigated the deviation in δ123Sb caused by mismatched signal intensities between the sample and the reference material. The matching range of signal intensity between the reference sample and the test sample was within -40% to 140%, ensuring satisfactory precision. Additionally, once the signal intensity of 121Sb exceeded 15V, the internal precision of the 123Sb/121Sb ratio no longer exhibited a significant decline. Measurements of DC and BJS were conducted using fs-LA-MC-ICP-MS, coupled with SN-MC-ICP-MS, backscattered electron maps (BSE) and elemental compositions, confirming the accuracy of this method and the homogeneity of the two potential reference materials.

A New Micro-Solid Phase Extraction Using ZnMnAl LDH Nano-Sorbent for Cu and Ni Determination in Natural Water and Soil

Hassan Elzain Hassan Ahmed, Zaki S. Seddigi, Mustafa Soylak*

2024,45(1),44-55,

DOI: 10.46770/AS.2023.310

[Abstract] (35) [PDF 1.88 M] (237)

Abstract:
Layered double hydroxides (LDHs) are a class of materials that may be readily synthesized in a laboratory environment. This work successfully conducted the synthesis of a new nanomaterial (ZnMnAl LDH). The characterization of this material was accomplished utilizing many analytical techniques, including FTIR, XRD, SEM-mapping, and FE-SEM. ZnMnAl LDH was employed to separate and enrich Cu(II) and Ni(II) from soil and water samples. The Cu and Ni ions were eluted from ZnMnAl LDH nanoparticles by using 2 mL of 0.1 mol L?1 of HNO3. The metal ions were quantified using flame atomic absorption spectrometry (FAAS). An investigation was conducted to examine the impact of many analytical factors on the efficiency of metal ions' extraction. These parameters include pH, sorbent amount, eluent volume, eluent concentration, sample volume, and possible interfering ions. The detection limits for Cu(II) and Ni(II) were found to be 0.74 and 0.52 μg kg?1, respectively. In addition, the relative standard deviation (RSD%) for Cu(II) is 3.8 and for Ni(II) is 1.9. The linear range for both analytes is 50–1000 μg L?1, and the preconcentration factor is 15 for both. The method’s validation was verified by the analysis of certified reference materials, namely BCR-505 estuarine water and GBW07429 (GSS-15) soil. For soil samples, Ni(II) and Cu(II) concentrations vary from 9.8 to 62.8 mg kg-1 and 9.9 to 73.5 mg kg-1, respectively. The technique described was used to quantify minute concentrations of copper (Cu) and nickel (Ni) in samples of both natural water and soil.

Accuracy Improvement for Minor Elements Determination Using Modified Self-absorption Correction and One-point Calibration Laser-induced Breakdown Spectroscopy

Tianxue Ou, Ning Zhang, Ruitao Lin, Nan Zhao*, Liang Guo, Jiaming Li*, Xiangyou Li, Qingmao Zhang

2024,45(1),56-66,

DOI: 10.46770/AS.2023.314

[Abstract] (17) [PDF 4.82 M] (298) [Supporting Information]

Abstract:
Determination of minor elements is the weakness of one-point calibration laser-induced breakdown spectroscopy (OPC-LIBS), which greatly hinders the further development of OPC-LIBS. The normalization in minor elements determination is seriously influenced by self-absorption effect of matrix element in laser-induced plasma. In this work, a modified self-absorption correction method was proposed in OPC-LIBS. The plasma temperature was determined by the slope of Saha-Boltzmann plots established for minor elements, and the electron number density was calculated from the Hα line. The internal reference line of the matrix element was corrected and iterated, until the maximum value of the self-absorption coefficient in the analytical line of minor elements was less than 1. The correction factors were determined based on elemental concentration in the reference sample and Boltzmann plots, and then were used in other samples for elemental determination. Twelve certified 6061 reference aluminum alloy samples and seven micro-alloy steel samples were used as examples for demonstration. Compared with both conventional OPC-LIBS and IRSAC & OPC, the dist in the proposed method (modified IRSAC & OPC) was reduced to 0.537-1.632 wt.% and 0.891-2.805 wt. % for the aluminum alloy and micro-alloy steel, respectively. These results showed that the proposed method can improve the accuracy of detecting minor elements using only one reference sample, which greatly facilitates the application of LIBS.

Study of the Change of Cr Speciation During the Diffusion-Reaction Process in Rock Samples Using Synchrotron Radiation Techniques

Hong Zhao, Jiujiang Zhao*, Jing Zhang, Caizhi Hu, Yongbing Liu, Wenbo Zhao, Zhaochu Hu

2024,45(1),67-73,

DOI: 10.46770/AS.2024.001

[Abstract] (16) [PDF 2.64 M] (318)

Abstract:
To study the change of chromium speciation in the Cr(VI) natural attenuation processes, which involve both the diffusion and redox reaction of Cr(VI), Cr(VI) diffusion-reaction experiments for carbonate rock samples were conducted. The synchrotron radiation μ-XRF and SEM-EDS mapping revealed that in organic-rich carbonate rock samples, fresh precipitated Cr was mainly located near the surface and associated with organic matters. Whereas, in the sample with low organic matter, Cr was distributed evenly. These results indicate that the organic matter in the fractures and pore space is the major natural reductant that reacts with Cr(VI) in organic-rich samples, and forms reducing products (Cr(III) precipitates), which might aggregate and block the pore throats, and prevent further diffusion of Cr(VI) into the rock matrix. The synchrotron radiation X-ray absorption near-edge structure (XANES) was used to obtain the distributions of Cr chemical forms. The results show that for organic-rich samples, the Cr(OH)3 fraction in the center was higher than that on the surface, whereas, for the samples containing low organic matter, no such significant difference was found. One possible explanation for these findings is that in organic-rich carbonate rock samples, the Cr(III) hydroxides, which aggregate in the zones near the surface, might age and transform from crystalline to the stable chemical forms of Cr(III) oxyhydroxide or even Cr(III) oxides, which could enhance the effect of Cr(VI) natural attenuation process. This work provides a feasible way to investigate the change of chromium chemical speciation during its diffusion-reaction processes in rock samples using synchrotron radiation techniques.

Determination of Trace Copper in Biological Samples by On-line Chemical Vapor Generation-Atomic Fluorescence Spectrometry

Liang He, Xiaofan Zhu, Li Wu, Xiandeng Hou*

, DOI: 10.46770/AS.2008.03.004

[Abstract] (263) [PDF 146.88 K] (1892)

Abstract:
On-line chemical vapor generation atomic fluorescence spectrometry (CVG-AFS) was, for the first time, used to determine trace copper in biological samples by merging acidified sample solution with potassium tetrahydroborate aqueous solution in the presence of micro-amounts of 1,10-phenanthroline. Nitric acid, for both sample digestion and chemical vapor generation, was used as the acid medium. CVG conditions and instrumental parameters were optimized for the best CVG efficiency, good gas/liquid separation, and efficient atomization/excitation. Under the optimized conditions, a limit of detection of 4 ng mL(-1) was obtained for copper, with a linear dynamic range of over three orders of magnitude. The proposed method was successfully applied to the determination of copper in biological certified reference materials.

Rapid Determination of Chemical Oxygen Demand by Flame AAS Based on Flow Injection On-line Ultrasound- assisted Digestion and Manganese Speciation Separation

Zhi-Qi Zhang*, Hong-Tao Yan, Lin Yue

, DOI: 10.46770/AS.2004.04.006

[Abstract] (250) [PDF 86.02 K] (1735)

Abstract:
A rapid, sensitive, and cost-effective method was developed for the determination of trace mercury in water samples by on-line coupling of flow injection (FI) sorption preconcentration with oxidative elution to cold vapor atomic fluorescence spectrometry (CV-AFS). race Hg(II) in aqueous solution was preconcentrated by on-line formation of mercury diethyldithiocarbamate complex (Hg-DDTC) and adsorption of the resulting neutral complex on the inner walls of a PTFE knotted reactor (KR). A mixture of 16% (v/v) HCl and 10% (v/v) H2O2 was used as the eluent to remove the adsorbed Hg-DDTC from the KR, then convert on-line the Hg-DDTC into Hg(II) prior to its reduction to elemental mercury by KBH4 for subsequent on-line CV-AFS detection. The tolerable concentrations of Cd(II) As(Ill) Se(IV) Fe(III), Co(II), Ni(II), and Cu(II) and Cu(II) for the determination of 0.1 mug L-I Hg(II) were 0.1, 10, 0.1, 0.1, 0.7, 1, 0.3, and 0.2 mg L-1, respectively. With a sample loading flow rate of 3.1 mL, min(-1) for a 60-s preconcentration, a detection limit (3sigma) of 4.4 ng L-I was achieved at a sample throughput of 36 samples h(-1). The precision (RSD, n = 11) was 1.7% at the 1 0, 1-mug L-1 Hg (11) level. The method was successfully applied to the determination of mercury in a certified reference material, GBW(E) 080392, and a number of local natural water samples.

Determination of Cadmium at the Nanogram per Liter Level in Seawater by Graphite Furnace AAS Using Cloud Point Extraction

Chun-gang Yuan, Gui-bin Jiang*, Ya-qi Cai, Bin He, Jing-fu Liu

, DOI: 10.46770/AS.2004.04.003

[Abstract] (257) [PDF 99.16 K] (1857)

Abstract:
A method based on?cloud?point?extraction?was developed to determine?cadmium?at?the?nanogram?per?liter?level?in?sea-water?by?graphite?furnace?atomic absorption spectrometry. Diethyldithiocarbamate (DDTC) was used as?the?chelating reagent to form Cd-DDTC complex; Triton X-114 was added as?the?surfactant.?The?parameters affecting sensitivity and?extraction?efficiency (i.e., pH?of?the?solution, concentration?of?DDTC and Triton X-114, equilibration temperature, and centrifugation time) were evaluated and optimized. Under?the?optimum conditions, a preconcentration factor?of?51.6 was obtained for a 20-ml, water sample.?The?detection limit was as low as 2.0 ng L-1 and?the?analytical curve was linear?in?the?10.0-200.0 ng L-1 range with satisfactory precision (RSD < 4.7%).?The?proposed method was successfully applied to?the?trace?determination?of?cadmium?in?seawater.

Development and Validation Method for the Determination of Rare Earth Impurities in High Purity Neodymium Oxide by ICP-MS

Man He, Bin Hu*, Zucheng Jiang, Yan Zeng

, DOI: 10.46770/AS.2004.01.002

[Abstract] (228) [PDF 154.90 K] (1827)

Abstract:
The analytical procedure for the determination of trace rare earth impurities in high purity neodymium oxide (Nd2O3) by ICP-MS is described. The effect of ICP-MS operating parameters on the REO(H)(+)/RE+ production ratio was studied in detail, and the optimal ICP operating conditions were established. In this context, the relationship between REO(H)(+)/RE+ production ratio and the bond strength of the rare earth oxides is also discussed briefly. For the correction of the spectral interference induced by the matrix (neodymium), a simple correction equation was used for correcting the interferences of the polyatomic ions NdO+ and NdOH+ with Tb-159 and Ho-165. The proposed method was applied to the determination of trace rare earth impurities in high purity Nd2O3\, and the analytical results were in good agreement with the recommended reference values.

Multielement Analysis of Alkaline-Resistant Glass and Basalt Glass Fibers Using Laser Ablation ICP-MS: A Useful Tool in Technical Textile Quality Control

J. Su. Becker, C. Pickhardt, N. Hoffmann, H. H?cker, J. Sa. Becker*

, DOI: 10.46770/AS.2002.01.001

[Abstract] (345) [PDF 135.56 K] (2009)

Abstract:
A powerful multielement analytical technique using laser ablation Inductively coupled plasma source mass spectrometry (LA-ICP-MS) for the sensitive determination of trace impurities in thin glass filaments, used as reinforcing material in the construction industry, was developed. The trace analysis was carried out directly on very thin solid strands (without any sample preparation steps) by LA-ICP-MS whereby a bundle of thin glass fibers (with a filament diameter of about 10 - 20 mum) was fixed on a thin, special tape of a target holder. The fibers were ablated in the ablation chamber with the aid of a commercial laser ablation system using a Nd-YAG laser at a wavelength of 266 nm). In order to verify the trace analytical data, the ablated T-glass fibers were analyzed using a quadrupole (LA-ICP-QMS) and double-focusing sector field mass spectrometer (LA-ICP-SFMS). The detection limits of the trace elements in glass fibers using the LA-ICP-MS with a quadrupole analyzer were in the sub mug g(-1) range, whereas using a sector,field mass spectrometer (LA-ICP-SFMS) the detection limits could be Improved by 3-4 orders of magnitude down to the low and sub ng g(-1) range. The multielement trace analytical method, developed for high-purity glass fibers, was applied to the determination of chemical composition on thin alkati-resistant glass and basalt fibers with finishing additives used in fine concrete for the building industry. The analytical results were quantified using standard reference materials (SRMs) of glass matrix, such as the NIST 612 glass SRM and the basalt geological reference glasses, KL-2G and ML3B-G, for the trace analysis of basalt glass fibers. The experimentally determined relative sensitivity coefficients (RSC) in LA-ICP-MS for both SRMs varied between 0.2 and 3 for most of the elements. An increase of the relative sensitivity coefficients was observed with increasing mass. The relative standard deviation (RSD) of most elements (N = 3) was T between 2 and 10%. The results of the trace element concentrations by LA-ICP-MS using different instrumentation are in good agreement.

On-line Ion Exchange Preconcentration in a Sequential Injection Lab-on-valve Microsystem Incorporating a Renewable Column With ETAAS for the Trace Level Determination of Bismuth in Urine and River Sediment

Jianhua Wang, Elo Harald Hansen*

, DOI: 10.46770/AS.2001.03.003

[Abstract] (214) [PDF 167.98 K] (1707)

Abstract:
A?sequential?injection?system?for?on-line?ion exchange separation and?preconcentration?of trace level amounts of metal ions with ensuing detection by electrothermal atomic absorption spectrometry (ETAAS) is described. Based on the use of?a?renewable microcolumn incorporated within an integrated lab-on-valve microsystem, the?column?is initially loaded with?a?defined volume of beads of an SP Sephadex C-25 cation exchange resin. After having been exposed to?a?metered amount of sample solution, the loaded bead suspension is precisely manipulated within the valve to allow reproducible elution of the retained analyte by 30 muL nitric acid (1: 16,v/v) which, via air segmentation, are then transported into the graphite tube for quantification. The content of the used?column?is afterwards discarded and new?column?material is aspirated for the next run. The ETAAS determination is performed in parallel with the?preconcentration?process of the ensuing sample. The performance of the?system?is demonstrated for the determination of bismuth. With 2.4-mL sample loading, an enrichment factor of 33.4,?a?detection limit of 27 ng 1:1, along with?a?sampling frequency of 10 h(-1) was obtained. The relative standard deviation was 2.3% for the determination of 2.0 mg 1:1 Bi (n = 7). The procedure was validated by determination of bismuth in?a?certified reference material CRM 320 (river sediment) and by bismuth spike recoveries in two human urine samples.

A Sequential Injection On-Line Column Preconcentration System for Electrothermal AAS Determination of Thallium in Geochemical Samples

Zhang-Run Xu, Shu-Kun Xu, Zhao-Lun Fang*

, DOI: 10.46770/AS.2000.01.004

[Abstract] (193) [PDF 116.38 K] (1667)

Abstract:
A?sequential?injection?system?for?on-line?sorbent extraction?preconcentration?in electrothermal atomic absorption spectroscopy was developed for the determination of trace thallium in geochemical samples. The TlBr4-1 complex was adsorbed on?a?20-mu L micro-column?(located at the tip of the furnace sampling probe) packed with XAD-8 resin. After sequentially aspirating separate zones of acetone, rinsing acid, and sample (pretreated with bromine) into?a?2.5-m long, 1-mm i.d. holding coil, the flow was reversed and directed to the?column. Sample loading, analyte adsorption,?column?rinsing and analyte elution were achieved within?a?single reversed syringe stroke. The adsorbed analyte was eluted into the furnace with 50 mu L acetone. Mutual mixing between sample, rinsing acid, and eluent were prevented by separating the zones with small air segments during metering. Tightening of?column?packing was avoided by?a?slight back-suction through the?column?after each operational cycle. With 1-mL sample loading, an enrichment factor of 15 was obtained with?a?detection limit of 18 ng/L thallium (3 sigma).?A?precision of 2.4% RSD (n=11, 4 μ g/L) and?a?sampling frequency of 11/hour were achieved. The method was applied to the analysis of geochemical samples. The results were in good agreement with the certified values of standard reference geochemical materials.

Trace Metals in Traditional Chinese Medicine: A Preliminary Study Using ICP-MS for Metal Determination and As Speciation

Xiaoru Wang, Zhixia Zhuang, Dahai Sun, Jiangxing Hong, Xihong Wu

, DOI: 10.46770/AS.1999.03.002

[Abstract] (292) [PDF 283.26 K] (1882)

Abstract:
The metal content in several TCM drugs was determined by ICP-MS. The efficiencies of different sample digestion methods were compared. Since one of the products studied is known to contain arsenic sulfides as a main ingredient, a solvent fractionation scheme was developed and applied to speciate As in the product. The metal content in the same TCM drug produced by different manufacturers was compared. The concentration of some metals such as Pb and Cd differs widely with different manufacturers, suggesting that their origin is primarily from external contamination. The high sensitivity and precision of the ICP-MS technique offers considerable advantages over conventional ICP-OES techniques for the analysis of complex samples such as TCM materials. Standardized analytic protocols based on ICP-MS are being developed fur the determination and characterization of metals and trace elements in TCM materials for product quality assessment.

Theory, design, and operation of a dynamic reaction cell for ICP-MS

Tanner S.D.* Baranov V.I.

, DOI: 10.46770/AS.1999.02.001

[Abstract] (202) [PDF 0.00 Byte] (0)

Abstract:
Theory, design, and operation of a dynamic reaction cell for ICP-MS