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  • 1  In situ Investigation of the Valence States of Iron-bearing Phases in Chang’E-5 Lunar Soil using FIB, AES, and TEM-EELS Techniques
    Bing Mo Zhuang Guo Yang Li Dan Zhu Xiaojia Zeng Xiongyao Li Jianzhong Liu Yanxue Wu
    2022, 43(1):53-59. DOI: 10.46770/AS.2022.014
    [Abstract](575) [HTML](0) [PDF 4.58 M](5225)
    Nanophase iron (np-Fe0) is a major product of space weathering and its presence significantly alters the reflectance spectral characteristics of lunar soil. Previous studies have established that the np-Fe0 particles originate from the reduction of ferrous ions in the plasma, in-situ decomposition of olivine and pyroxene, and disproportionation of ferrous ions in solid ferrosilicates. In this study, sample charging effects were eliminated and in situ nanoscale valence state analysis of iron-bearing phases in Chang’E-5 lunar soil was conducted by combining focused ion beam (FIB) microscopy, Auger electron spectroscopy (AES), and transmission electron microscopy-electron energy loss spectroscopy (TEM-EELS) techniques. The results indicate that the contents and valence states of iron in the np-Fe0 particles, amorphous matrix, and ferrosilicates differ. The np-Fe0 particles were found to be composed of pure metallic iron, whereas ferrous and ferric iron ions were present in olivine crystals and the amorphous matrix, respectively. The discovery of both metallic and ferric iron in the amorphous matrix of Chang’E-5 lunar soil offers new insights regarding the disproportionation reaction of Fe2+ on the lunar surface. This study demonstrates that the combination of FIB, AES, and TEM-EELS is an effective and precise approach for analyzing the valence states of iron-bearing phases in lunar soil, which can be extended to other extraterrestrial samples and other multivalent elements.
    2  Design, Function, and Implementation of China's First LIBS Instrument (MarSCoDe) on the Zhurong Mars Rover
    Xiong Wan Chenhong Li Hongpeng Wang Weiming Xu Jianjun Jia Yingjian Xin Huanzhen Ma Peipei Fang Zongcheng Ling
    2021, 42(6):294-298. DOI: 10.46770/AS.2021.608
    [Abstract](438) [HTML](0) [PDF 14.32 M](5944)
    MarSCoDe (Mars Surface Composition Detector) is China's first instrument for Mars material analysis, which accompanies the Zhurong Mars rover landing on Utopia Planitia and will detect interested Martian rock and soil targets based on laser-induced breakdown spectroscopy (LIBS) technique. MarSCoDe consists of a bioxial pointing mirror (BPM), an optical head, a calibration targets assembly (CTA), a spectrometer module (SM) and a payload controller. The MarSCoDe is scheduled to analyze twelve major elements. To achieve accurate quantitative analysis and classification of Mars targets, a PSO (particle swarm optimization)-based calibration scheme is adopted to correct the spectral shift due to the temperature change on Mars, and then a convolutional neural network (CNN) was proposed to implement the analysis of elements. Finally, the mineral types of Martian objects will be identified according to the alkali silica ratio. The detection results of the MarSCoDe will provide further information about the evolution of Mars.
    3  Fast Quantification and Speciation of Selenium in Dietary Supplements through Handheld XRF and Synchrotron Radiation XAS
    Yunyun Li Jiating Zhao Lina He Liming Wang Liwei Cui Bai Li Yu-Feng Li
    2020, 41(3):127-131. DOI: 10.46770/AS.2020.03.005
    [Abstract](400) [HTML](0) [PDF 731.58 K](1660)
    The handheld X-ray fluorescence spectrometer (XRF) has the advantages of being easy to carry, simple in operation, non-destructive, and offers fast and relatively accurate detection, while synchrotron radiation X-ray absorption spectroscopy (XAS) has been used for the selenium (Se) speciation of Se-enriched yeast and Se hyperaccumulators. In this study, we propose the application of a handheld XRF in combination with XAS for the fast quantification and speciation of Se in commercially available dietary supplements. The results of total Se determined by handheld XRF were in good agreement with ICP-MS data, which was also consistent with the labeled value of Se dietary supplements. The XAS analysis of the tested samples showed that Se was mainly present in the form of organic Se. The proposed method is practical and simple for high throughput label verification and quality control of Se dietary supplements. It can, therefore, be a useful method not only for researchers but also for regulators and producers in the analysis of Se dietary supplements.
    4  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
    2002, 23(1):1-6. DOI: 10.46770/AS.2002.01.001
    [Abstract](328) [HTML](0) [PDF 135.56 K](1860)
    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.
    5  Simultaneous or Sequential Multi-element Graphite Furnace Atomic Absorption Spectrometry Techniques: Advances Within the Last 20 Years
    Ioannis N. Pasias Nikolaos I. Rousis Aikaterini K. Psoma Nikolaos S. Thomaidis
    2021, 42(6):310-327. DOI: 10.46770/AS.2021.707
    [Abstract](296) [HTML](0) [PDF 1.65 M](2250)
    Electrothermal or graphite furnace atomic absorption spectrometry (ETAAS or GFAAS) is one of the most widely used techniques for determining elements in different matrices (e.g., foodstuffs, pharmaceuticals, biological specimens, nanomaterials, polymers, fuels and environmental media). Numerous elements can be simply and quickly determined with high precision and accuracy, low detection limits, and at moderate cost. The technique is also suitable for direct solid and slurry sample analysis. A crucial feature of this technique is that it can perform simultaneous or sequential multi-element analysis. Over the years, many instruments have come on the market for multi-elemental analysis using mostly line source (LS) GFAAS and high-resolution continuum source (HR-CS) GFAAS. This review covers publications from 2000 to 2020 related to the simultaneous or sequential multi-elemental analysis by LS-GFAAS and HR-CS-GFAAS. Mainly the applications, the limits of detection, the use of internal standardization and other aspects regarding the matrix, pyrolysis and atomization temperatures and modifiers are discussed. Finally, a critical comparison is made between the LS-GFAAS and HR-CS-GFAAS techniques.
    6  Quantitative Analysis of Gold Nanoparticles in Single Cells with Time-resolved ICP-MS
    Jinhui Liu Lingna Zheng Junwen Shi Xing Wei Xue Li Mingli Chen Meng Wang Jianhua Wang Weiyue Feng
    2021, 42(3):114-119. DOI: 10.46770/AS.2021.102
    [Abstract](286) [HTML](0) [PDF 4.24 M](6957)
    Single-cell inductively coupled plasma mass spectrometry (SC-ICP-MS) has been introduced for the analysis of intracellular essential elements and nanoparticles (NPs) at the single cell level. However, it is still quite challenging for accurate and reliable determination. In this work, a high-efficiency sample introduction system was used for single cell analysis with ICP-MS. The system includes a microconcentric nebulizer, a low-volume single pass spray chamber, and a syringe pump. The transport efficiency of single cells was greatly improved to ~12%. In addition, 197Au signals in individual HepG2 cells, after incubation with gold nanoparticles (AuNPs) at the concentrations of 0.1, 0.5, and 1 μM for 12 h, were analyzed by time-resolved ICP-MS with dwell times of 100 μs and 5 ms, respectively. The 197Au signal-to-background ratio (S/B) at 100 μs dwell time was much higher than at 5 ms. For quantitative analysis, AuNP standard reference materials were used for calibration. The SC-ICP-MS data using NP calibration were in good agreement with those using solution ICP-MS analysis, validating the developed SC-ICP-MS method.
    7  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
    1999, 20(3):86-91. DOI: 10.46770/AS.1999.03.002
    [Abstract](278) [HTML](0) [PDF 283.26 K](1776)
    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.
    8  An Improved Analytical Protocol for the Determination of Sub-nanogram Gold in 1–2 g Rock Samples Using GFAAS After Polyurethane Foam Pretreatment
    Yanhong Liu Zaicong Wang Dingshuai Xue Yueheng Yang Wengjun Li Huai Cheng Clifford Patten Bo Wan
    2020, 41(3):132-140. DOI: 10.46770/AS.2020.03.006
    [Abstract](274) [HTML](0) [PDF 4.12 M](1855)
    Gold (Au) is an important indicator in many geochemical studies, but the quantification of sub-nanogram Au in rock samples is challenging. Herein, a simple and rapid analytical protocol for the determination of sub-nanogram Au in 1–2 g rock samples is established using graphite furnace atomic absorption spectrometry (GFAAS) after polyurethane foam (PUF) pretreatment. By employing the optimized extraction conditions, Au recovery can reach up to 95% even for 0.1 ng g-1 Au. Six international rock reference materials (RMs) of basalt, diabase, and gabbro were used to validate the feasibility of this protocol. The results are in agreement with previously reported values obtained using instrumental neutron activation analysis (INAA) or inductively coupled plasma mass spectrometry (ICP-MS), where less or the same amount of sample rock powders were used. Furthermore, the rock RMs of TDB-1 and JB-2 are found to be homogeneous with a precision of < 10% (2 RSD) using only 1 g of sample mass, making them suitable for method validation or quality control for inter- laboratory comparison. Owing to its simplicity, speed, reliability, and low cost, this protocol can be used for Au measurement and tracer provenance in the geochemical community.
    9  Estimation of Isotopic Reference Values for Pure Materials and Geological Reference Materials
    Wen Zhang Zhaochu Hu
    2020, 41(3):93-102. DOI: 10.46770/AS.2020.03.001
    [Abstract](266) [HTML](0) [PDF 1.73 M](2686)
    Reference materials (RMs) are the foundation in isotopic analysis, and the assignment of reference values of isotope ratios in RMs is a complex process. In this study, we established new isotopic reference values and its uncertainties for the Sr, Nd, Hf and Pb isotope ratios in 18 commonly used pure materials and rock RMs, and for Hf and O isotope ratios in five zircon RMs, following the ISO guidelines and procedures in the IAG Certification Protocol. The original data were collected from the geochemical database “GeoReM”. An estimation method for generating reference values of isotope ratios was developed, including a data filter process, technical criteria assessment and robust statistical calculation. The generated analytical results demonstrate the same instrumental performance with both TIMS and MC-ICP-MS for Sr and Nd isotopic analysis. However, significant discrete data for the Pb isotope ratios obtained by TIMS and MC-ICP-MS are evident, indicating existing challenges for accurate Pb isotopic analysis. It was found that 91500 is not a suitable Hf isotopic RM for micro-analysis due to the heterogeneous Hf isotopic composition and the Ple?ovice zircon may be a more ideal alternative. This study provides a powerful protocol and practical examples for estimating reference values of isotope ratios in frequently used RMs.
    10  A Novel Synergetic Salt- and Acid-induced Ligandless Mixed Micelle Cloud Point Extraction of Ultratrace Levels of Cd, Hg, Bi, and Tl From Petrochemical Effluents Followed by ETAAS Determination
    K. Ravi Kumar K. Madhavi P. Shyamala N.N. Meeravali Sunil Jai Kumar
    2018, 39(3):118-125. DOI: 10.46770/AS.2018.03.005
    [Abstract](263) [HTML](0) [PDF 176.31 K](1072)
    A new synergetic salt- and acid-induced ligandless mixed micelle cloud point extraction procedure was developed for the simultaneous separation and preconcentration of Cd, Hg, Bi, and Tl from petrochemical effluents and groundwater samples. The cationic mixed micelles are formed by the micelle-micelle interaction of cationic cetylpyridinium ammonium bromide (CPAB) and nonionic Triton? X-114 micelles, which act as an ion pair and extracting agent. Due to the synergetic effect of potassium iodide and sulfuric acid, the hydrophilic anionic Cd, Hg, Bi, and Tl iodide species are formed. These also induce the clouding phenomenon in cationic mixed micelles. The strong electrostatic interaction between the mixed micelles head groups and the anionic iodide species form the hydrophobic ion pairs which are separated from the bulk aqueous phase into a small mixed micelle-rich phase, thus avoiding the addition of an external chelating agent. Under the optimized conditions, a pre-concentration factor of nearly 20 times was obtained for all of the elements. The limits of detection obtained were 0.0005, 0.2, 0.04, and 0.05 ng mL-1 for Cd, Hg, Bi, and Tl, respectively. The recoveries were in the range of 93–102% at 0.1 to 10 ng mL-1 with a relative standard deviation of 2–10%. The accuracy of the method was validated by analysis of certified reference materials BCR 714 Initial Influent, BCR 715 Industrial Effluent, BCR 610 Groundwater, and NIST 1643e, 1643f, and 1642b Trace Elements in Water. The method was also applied to real samples of petrochemical effluents and groundwater collected locally. A continuum source electrothermal atomic absorption spectrometer (CS-ETAAS) was used for the determination of the elements.
    11  Rapid Analysis of Soil Samples by Laser Ionization Mass Spectrometry
    Zhouyi Xu Le Hang Qiao Lu Wei Hang Benli Huang
    2020, 41(4):141-147. DOI: 10.46770/AS.2020.04.001
    [Abstract](261) [HTML](0) [PDF 1.73 M](2712)
    In this work, laser ionization mass spectrometry (LIMS) was developed in the laboratory and used to analyze geochemical standard reference soil samples to demonstrate the rapid analytical capability of this technique. With the help of high laser irradiance and low-pressure buffer gas, sufficient atomization and quite uniform ionization can be achieved. Little spectral interference appeared in the spectra produced by LIMS, while the signal intensity is fairly proportional to the element concentration. These features enable LIMS to acquire semi-quantitative analysis without reference materials. To further improve the quantitative accuracy, correction factors can be obtained using reference materials, while these correction factors can virtually be applied for elemental quantitation of all soil samples. The results show that LIMS is a reliable technology for the rapid analysis of metallic and non-metallic elements in soil samples.
    12  Review: Application of LIBS to Elemental Analysis and Mapping of Plant Samples
    Vivek K. Singh Neha Sharma Onkar N. Verma Virendra K. Singh Durgesh K. Tripathi Yonghoon Lee Sandeep Kumar Piyush K. Rai M.A. Gondal
    2021, 42(2):99-113. DOI: 10.46770/AS.2020.201
    [Abstract](259) [HTML](0) [PDF 2.06 M](1899)
    Trace minerals and metallic elements play a key role in plant metabolism and function. Therefore, it is important to understand the movement and distribution of trace minerals within various parts of plants in order to understand their metabolic pathways. Information on the localization of minerals can be utilized in the fields of plant science, agriculture, and food technologies. In this context, herein, we review the feasibility of application of laser-induced breakdown spectroscopy (LIBS) as a technique for trace element detection and mapping in different plant matrices. LIBS is a well-established technique that can be used to perform rapid multi-elemental detection in various types of samples, including plants. Owing to the unique capabilities of LIBS, its field applications are growing rapidly, particularly in the area of plant science. Here, our primary emphasis is on the quantitative and qualitative elemental imaging of different varieties of plant species that are of importance as medicines and foodstuffs. In this review article, we present an exhaustive survey of recent developments, including technical advances and recent work involving the detection of nanoparticles in plant samples and in the monitoring of soil content. The future potential of LIBS and the viability of its possible applications to the detection of essential minerals and heavy metals in plants used as foods or of medicinal importance are also discussed.
    13  Matermetallomics: Concept and Analytical Methodology
    Qing Li Zhaoqing Cai Yan Fang Zheng Wang
    2021, 42(5):238-246. DOI: 10.46770/AS.2021.101
    [Abstract](256) [HTML](0) [PDF 2.67 M](3891)
    The emerging field of matermetallomics refers to all research activities aimed at the clarification of the role and function of metallic elements in materials. This paper discusses the concept of matermetallomics and the related analytical techniques used for probing the interactions between structure-activity relationships. The main object of matermetallomics research is metallic elements in materials, and includes the significance and contributions to materials science. This paper also introduces the analytical approaches used in matermetallomics, which includes the techniques of imaging, spectroscopic, X-ray-based, ion beam, MS-based and atomic spectrometry.
    14  Further Evaluation for High-precision Isotopic Measurement of 205Pb-spiked Pb by Dynamic Multiple Ion Counting
    Zhu-Yin Chu Chao-Feng Li Wen-Gui Liu Wei Wang Jing-Hui Guo
    2020, 41(4):148-153. DOI: 10.46770/AS.2020.04.002
    [Abstract](255) [HTML](0) [PDF 2.37 M](1880)
    A high-precision MIC-ID-TIMS (multiple ion counting-isotope dilution-thermal ionization mass spectrometry) Pb isotope ratio measurement method (using 205Pb as spike) with a TRITON Plus TIMS, which is equipped with a 205Pb-Pb MIC array, using a two-line multi-dynamic data collection method, was thoroughly re-set and re-evaluated, based on our previous work.1 After some vital modifications, better than 0.01% RSE internal precision on 207Pb/206Pb for a 205Pb-spiked NIST981 with ~ 50 pg of Pb load was achieved with a measurement time of about 100 min. This is more precise compared to the traditional isotopic measurement method for the 205Pb-spiked Pb, using a single secondary electron multiplier (SEM) with five peak jumps, provided with similar ion beam intensities and measurement time. The external precision on 207Pb/206Pb was better than 0.1% (2RSD, n = 24), which is much better than that achieved by the static MIC method as previously reported1, 2. The present work indicates that the 205Pb-Pb MIC array of the TRITON Plus TIMS can be successfully used for zircon ID-TIMS U-Pb dating with high precision, particularly is useful for samples containing extremely small amounts of Pb (down to several pico-grams).
    15  Study of Molecular and Elemental Changes in Nematode-infested Roots in Papaya Plant Using FTIR, LIBS and WDXRF Spectroscopy
    Neha Sharma Yugal Khajuria Virendra K. Singh Sandeep Kumar Yonghoon Lee Piyush K. Rai Vivek K. Singh
    2020, 41(3):110-118. DOI: 10.46770/AS.2020.03.003
    [Abstract](253) [HTML](0) [PDF 2.80 M](1826)
    Papaya is a tropical fruit of the Carica papaya plant and grown all over the world. Root knot nematodes are one of the major problems in papaya fruit crop production and causes maximum yield loss every year by slowly killing the plant. In this article, we study healthy as well as nematode-infested papaya plants at the atomic and molecular levels to obtain information about the causes and changes occurring in the plant after infestation. Microscopic observations were made to check the presence of pathogens in the plant. Elemental profiling of healthy and infested papaya plants was assessed by using two advanced spectroscopic techniques, namely laser-induced breakdown spectroscopy (LIBS) and wavelength dispersive X-ray fluorescence spectroscopy (WDXRF). The structural changes in the complex bio compounds, such as starch, protein, lipids, fatty acids, and carbohydrates, were assessed by Fourier transform infrared spectroscopy (FTIR). The elemental and molecular profiling results of the infested vs. the healthy papaya plants were compared to establish why the plants die.
    16  Determination of Trace Copper in Biological Samples by On-line Chemical Vapor Generation-Atomic Fluorescence Spectrometry
    Liang He Xiaofan Zhu Li Wu Xiandeng Hou
    2008, 29(3):93-98. DOI: 10.46770/AS.2008.03.004
    [Abstract](248) [HTML](0) [PDF 146.88 K](1759)
    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.
    17  Micro-XRF Study of the Troodontid Dinosaur Jianianhualong Tengi Reveals New Biological and Taphonomical Signals
    Jinhua Li Rui Pei Fangfang Teng Hao Qiu Roald Tagle Qiqi Yan Qiang Wang Xuelei Chu Xing Xu
    2021, 42(1):1-11. DOI: 10.46770/AS.2021.01.001
    [Abstract](247) [HTML](0) [PDF 10.27 M](3301)
    Jianianhualong tengi is a key taxon for understanding the evolution of pennaceous feathers as well as of troodontid theropods. It is known by only the holotype, which was recovered from the Lower Cretaceous Yixian Formation of western Liaoning, China. In this study, we carried out a large-area micro-X-Ray fluorescence (micro-XRF) analysis of the holotype of Jianianhualong tengi via a Brucker M6 Jetstream mobile XRF scanner. The elemental distribution measurements of the specimen show an enrichment of typical bone-associated elements, such as S, P and Ca, which allows to visualize the fossil structure. Additionally, the bones are enriched with several heavier elements, such as Sr, Th, Y and Ce relative to the surrounding rocks. The enrichment is most likely associated to secondary mineralization and the phosphates from the bones. Interestingly, the plumage shape correlates with an enrichment in elements, such as Cu, Ni and Ti, consistent with the findings of a previous study1 on Archaeopteryx using synchrotron imaging. Elemental variations among the skeleton, the unguis and the sheath blade further indicate their possible compositional or ultrastructural differences, providing new biological and taphonomic information on the fossilized keratinous structures. An in-situ and nondestructive micro-XRF analysis is currently the most ideal way to map the chemistry of meter-sized fossils and has so far been mainly restricted to small samples. Micro-spatial chemical analysis of larger samples usually required a synchrotron facility. Our study demonstrated that a laboratory-based large-area micro-XRF scanner can provide a practical tool for the study of large specimens, thus allowing to collect full chemical data in order to obtain a better understanding of evolutionary and taphonomic processes.
    18  Multi-elemental Analysis by Energy Dispersion X-ray Fluorescence Spectrometry and Its Application on the Traceability of Soybean Origin
    Hanqing Lai a b Jialin Xi c Jianchun Sun d Weizhong He e Zhaohui Wang a f Chuangmu Zheng b d Xuefei Maob
    2020, 41(1):20-28. DOI: 10.46770/AS.2020.01.003
    [Abstract](242) [HTML](0) [PDF 2.41 M](1031)
    In this work, a commercial energy dispersion X-ray fluorescence (ED-XRF) spectrometer was utilized to measure the trace elements in soybean samples. After optimizing the radiation time and calibration strategy, ED-XRF was able to successfully measure 9 elements (Mg, K, Ca, Mn, Fe, Ni, Cu, Zn, and Rb) in 296 soybean samples from five producing areas of northern China (Henan, Inner Mongolia, Xinjiang, Heilongjiang, and Liaoning). Since principal component analysis (PCA) is not able to distinguish all growing areas completely, the multi-layer perceptron (MLP) procedure was employed which demonstrated to have a powerful classification capacity with an accuracy rate of 96.2%. XRF is a type of solid sampling analytical method, which is fast, accurate and partly portable for multi-elemental analysis. The combination of MLP and ED-XRF overcomes the analytical disadvantages found with ICP-MS or wavelength dispersion XRF analysis, and provides a novel and fast testing method for on-site recognition of food origin traceability.
    19  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
    2004, 25(4):170-176. DOI: 10.46770/AS.2004.04.003
    [Abstract](242) [HTML](0) [PDF 99.16 K](1736)
    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.
    20  Eppawala-AP, Sri Lanka, an Apatite Reference Material for High Precision Chlorine Isotope Analysis
    Yang Li Qiu-Li Li Guo-Qiang Tang Anthony Gargano Zachary Sharp Amarasooriya Pitawala Lei Zhao Ming-Guo Zhai Xian-Hua Li
    2020, 41(2):51-56. DOI: 10.46770/AS.2020.02.001
    [Abstract](240) [HTML](0) [PDF 895.13 K](2423)
    In this study, an apatite reference material (RM), Eppawala-AP, was obtained and calibrated from a mega-crystal of Eppawala carbonatite (collected in northwestern region of Sri Lanka) to standardize chlorine isotope analysis. A homogeneity test and chlorine isotope composition measurement of the RM were performed using secondary ion mass spectrometry (SIMS) and continuous gas flow isotope ratio mass spectrometry (CF-IRMS), respectively. The RM, with a recommended δ37Cl value of -0.74 ± 0.15‰, can be utilized as a matrix-matched standard (~1.55 wt. % Cl) to correct the instrumental mass fractionation (IMF) during in situ analysis, or as a quality control material for both in situ and bulk analysis, to facilitate high quality measurement and inter-laboratory data comparison. This RM is available to the scientific community by contacting the corresponding author. Our homogeneity test indicates an absence of orientation effect during SIMS analysis for the specific apatite grain investigated here, and suggests a repeatability of 0.13‰ for SIMS apatite chlorine isotope analysis. The matrix effect of minerals with complex chemistry predicts that the chlorine content is a controlling factor of IMF during in situ apatite chlorine isotope analysis; hence, additional RMs with variable concentrations of chlorine are required for routine δ37Cl measurement.

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