• 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
    2020 SCI IF: 2.04

    Special Issue Call for Papers:

    'Microanalysis methods for extraterrestrial samples'

    On 17th December 2020, the sample capsule of Chang’E-5 successfully landed at Dorbod Banner, Inner Mongolia, China. Forty-four years since Luna 24 mission in 1976, new lunar samples have been returned to Earth. However, the lunar samples are precious and rare with the properties of uniformity and small particle size, posing a challenge for analytical techniques. Here we intend to publish a special thematic issue of Atomic Spectroscopy on Microanalytical Techniques for Extraterrestrial Samples, which will support the research on mineralogy, petrology, chronology, magnetism, and geochemistry of the Chang’E-5 lunar samples and be applied to the research on both terrestrial and extraterrestrial samples in the future.

    All papers offered to this thematic issue will be subject to the original research review procedures of Atomic Spectroscopy, the deadline for paper submission is supposed to be 1st December 2021. The publication date will be 1st February 2022.

    If you would like to offer a paper, please email the manuscripts to our guest editors:

    1. Jinhua Li (jinhua.li@at-spectrosc.com): Microscopy and Microspectroscopy Analysis

    2. Xiongyao Li (xiongyao.li@at-spectrosc.com): Physical Property Analysis

    3. Yongsheng He (yongsheng.he@at-spectrosc.com): High Precision Isotopic Analysis

    4. Wei Yang (wei.yang@at-spectrosc.com): In Situ Elemental and Isotopic Analysis

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      Abstract:
      A valid method for trace silver (Ag) detection in geological samples was developed in this study using aerosol dilution inductively coupled plasma-mass spectrometry after extraction with inverse aqua regia. This was proposed primarily to reduce the interference from Nb and Zr during mass spectrometric measurements. Almost 93% of Nb and Zr was removed after the extraction. By mixing an appropriate amount of Ar with the sample aerosol using an aerosol dilution system prior to plasma, the residual Nb oxides and Zr oxides or hydroxides could be successfully removed. The relative yields of the interfering oxides and hydroxides were as low as 0.087% (NbO/Nb) and 0.013% (ZrOH/Zr), which were 3–5 times lower than those in the traditional mode without the addition of Ar. Moreover, the signal-to-noise ratio of Ag was five times higher than that in the traditional mode. The proposed method was applied to the determination of Ag in 68 standard reference materials (SRMs) of soil, sediment, and rock. The results for 47 of these geological SRMs were in good agreement with the reference values. The Ag levels in three SRMs (GSP-2 Granodiorite, STM-2, and SGR-1b) are being reported for the first time herein. For these SRMs, 10 separate aliquots of the sample were digested and analyzed over a period of three months, and analysis revealed that the determined values were reasonable. Thus, the proposed method shows significant potential for the accurate determination of trace Ag in various geological samples.
      Abstract:
      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 2020related 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.
      Abstract:
      Laser-induced with the increasing popularity of alternative breads, investigating their health benefits and risks is vitally important. The bioaccessibility of potentially toxic elements in these breads could indicate a potential risk to consumers. The continuous online leaching method (COLM) involves the sequential leaching of a mini-column of food by artificial saliva, gastric juice, and intestinal fluid with real time monitoring of elements being released. Because the dissolution equilibrium is shifted to the right from continuous exposure to fresh reagent, it assesses bioaccessibility in three gastrointestinal matrices in less than 30 min and includes valuable kinetic extraction information. In this study, a gluten-free (GF) and a rye bread were analyzed for As, Cd, and Pb before and after toasting. Toasting lowered all PTE concentrations by a factor of 1.5 (As in rye bread) to 2.5 (Cd in rye bread). Most of the PTEs present were bioaccessible whether the bread was toasted or not. In the case of As, a significant portion is in the form of As(III) and As(V). COLM analysis allowed for Pb sourcing, revealing two potential sources of Pb being released separately in gastric juice from rye bread based on their significantly different 206Pb/207Pb and 208Pb/206Pb isotope ratios. Comparison with Pb ratios reported in previous literature revealed that some of the gastric-mobile Pb in rye bread came from the Pb historically added to gasoline in North America. This source completely vanished upon toasting rye bread.
      Abstract:
      The aim of this review is to provide a brief introduction to recent research advances in in-situ online detection of atmospheric pollutants based on laser-induced breakdown spectroscopy (LIBS) under atmospheric environments. Atmospheric pollution has drawn much public attention, and there is increasing demand for rapid and accurate evaluation of atmospheric environments. LIBS has the advantages of in-situ online detection, simultaneous multi-element analysis, and noncontact measurement, making it a highly competitive analytical technique in the field of environmental monitoring. In terms of the different target samples, some typical research cases, including atmospheric particulate matter, atmospheric pollution sources, halogens in VOCs, atmospheric sulfur, and stable isotope abundance, are presented to illustrate the current development and problems of LIBS detection in this field.
      Abstract:
      The method of isotope dilution and tracing, based on ethylation-purge and trap-gas chromatography (GC)- inductively coupled plasma mass spectrometry (ICP-MS), has been widely used for the accurate analysis of methylmercury (MeHg) and for tracking its environmental fates (e.g., formation/degradation). However, the tedious ethylation derivatization and purge and trap processes limit analytical throughput. In this work, an automatic ethylation derivatization and purge and trap method, followed by GC separation, pyrolysis, and ICP-MS detection, was developed for MeHg analysis. The throughput and detection limits of this proposed method for MeHg were 7.5 min/sample and 0.03 ng L-1, respectively, with a relative standard deviation of 3.7%. The accuracy of the developed method was validated by the analysis of a spiked water sample and a certified reference material (DORM- 4, Fish protein) using isotope dilution (Me201Hg). In addition, anaerobic Geobacter sulfurreducens PCA-mediated methylation of Hg2+ and demethylation of MeHg was monitored by using double-enriched isotope tracing (199Hg2+ and Me201Hg). This automatic ethylation-purge and trap-GC-ICP-MS method is promising for routine MeHg analysis with isotope dilution/tracing.
      Abstract:
      Trends and advances in the development and application of inductively coupled plasma tandem quadrupole mass spectrometry (ICP-QMS/QMS) with a reaction cell is reviewed mainly based on publications from January 2018 to July 2021. ICP-QMS/QMS has been applied in various research fields covering the sciences of biology, energy, environmental, food/medical, geology, materials, and radionuclide. The objectives of analysis cover the determination of elemental concentration, ion-gas reaction, isotope analysis, single particle analysis, and chemical speciation analysis. Measurement of most elements in the periodic table are reported except for H, N, O, F, rare gas, and some of the radionuclides. In addition to the default reaction/collision gases (i.e., He, H2, O2, and NH3), N2O, CO2, CH4, CH3F, C2H4, and C2H6 have been used as reaction gases to improve the capability of separating spectral interferences or to study the ion-molecule reactions. Typical applications of ICP-QMS/QMS analysis in the major research fields are also discussed.
      Abstract:
      MarSCoDe (Mars Surface Composition Detector) is China's first instrument for Mars material analysis, which accompanies with 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.
      Abstract:
      Rare earth elements (REE) are important tools in geological studies. Accurate determination of REE concentrations can be affected in geological samples with low REE levels and/or high levels of interfering barium. Development of chemical separation methods allowing to isolate REE from other matrix components is a thorough approach to overcome this issue. In this study, a simple, RE resin-based separation method was developed and tested for a variety of sample solutions (mixed element solutions, shale, carbonate and granite). The method shows a good REE recovery and is efficient for the removal of matrix element, and notably Ba. The method is suitable for precise determination of the Eu contents in rock samples with high barium content.
      Abstract:
      Laser-induced breakdown spectroscopy (LIBS) was applied for the characterization of the methane-air laminar diffusion flame, revealing the spatial distribution of its composition. From the measurement, it was found that distribution of the atomic and ionic N emissions produced by the flame had obvious differences, which were mainly distributed in the air area and flame area, respectively. A comparison of the LIBS spectra of air, methane gas, and methane-air laminar diffusion flame showed that the atomic N emissions were mainly produced by the excitation of N2, and the ionic N emissions were more related to the N-containing combustion products. In addition, the correlation between typical emissions and the flame temperature measured by thermocouple was estimated to show that the tendency of the changes in temperature can be characterized by C2 emission intensities. This work provides a new method for real-time online flame temperature measurement, and also provides a reference for revealing the formation process and conversion pathway of each component in the flame.
      2021,42(5),231-237
      DOI: 10.46770/AS.2021.805
      Abstract:
      The COVID-19 pandemic has led to severe threat globally. As a result, scientists are increasing their efforts in developing testing methods, antiviral drugs, and vaccines, to diagnose, treat, and defend against COVID-19 respectively. Although RT-PCR and antigen tests are used for the screening of COVID-19, there are many disadvantages including high cost, long processing time, and false-negative results. With the exception of supportive care, no specific treatment for COVID-19 has been established. Metallomics focuses on the systematic study of the interactions and functional connections of metallic/metalloid ions and their species with genes, proteins, metabolites, and other biomolecules within organisms and ecosystems. It has been applied in the screening of various cancers, neurodegenerative diseases, and viral infections and metallodrug development with the advantages of high throughput, low risk of cross-infection, low cost, and ready availability. Therefore, we proposed the use of metallomics for the screening and metallodrug development of COVID-19. An operational work scheme is also presented.
      2021,42(5),238-246
      DOI: 10.46770/AS.2021.101
      Abstract:
      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.
      2021,42(5),247-253
      DOI: 10.46770/AS.2021.107
      Abstract:
      In this paper, the concept of archaeometallomics is put forward to study the role of metal elements in cultural relics. An example is the influence of metal elements in the identification of their origin, dating, authenticity and the technology used for the production of ancient ceramics. This analysis also provides the social and cultural connotations of the development process of that time and shows that there is a close relationship between the rich glaze varieties and the metal elements in porcelain. The application of different analytical techniques in studying metallic elements in ancient ceramics is also briefly summarized. The construction of a metal element composition database and the related questions in the glaze color-forming mechanism of ancient relics should be considered an important research direction for future works.
      2021,42(5),254-261
      DOI: 10.46770/AS.2021.105
      Abstract:
      Uranium (U) is one of the most concerned radioactive metals on earth. Thus, to unravel the transportation and transformation of U in the food webs, and tracing its ecological and health risks are of utmost and timely importance. Radiometallomics, in conjunction with the research methods, mainly focus on establishing the ecological and biological metabolisms and behaviors of radiometals/metalloids. In particular, synchrotron radiation (SR) has many advanced properties, e.g., high brightness and collimation, and a wide energy spectrum, which make it a unique technique in the study of metal distribution and speciation analysis. To date, SR-based techniques are widely applied in the environmental sciences; however, a systematic summary of its application in radiometallomics is still lacking. This review assembled and compared the conventional and advanced techniques, especially SR-based radiometallomics used in studying U in environmental matrixes, with the aim that this information will help to develop further combined metallomics approaches in the U analysis and risk assessment of contaminated areas.
      2021,42(5),262-270
      DOI: 10.46770/AS.2021.104
      Abstract:
      The emerging field of metrometallomics refers to the qualitative and quantitative measurement of metallic analytes in the metrological sciences. Inductively coupled plasma mass spectrometry (ICP-MS) has the merits of multi-elemental quantification with very low detection limits. It has been applied for the quantification of peptides and proteins by measuring the concentration of certain elements, which is a very important applications area in metrometallomics. This review showcases the application of ICP-MS on the quantification of metalloproteins through the quantification of protein-bound metal/metalloid elements, intrinsic metal/metalloid elements, or labeled metal/metalloid elements. The results of study also suggest that metrometallomics can be a useful tool in the development of certified reference materials of metalloproteins.
      2021,42(5),271-277
      DOI: 10.46770/AS.2021.708
      Abstract:
      In this study, sources of Pb are investigated using the 206Pb/207Pb isotopic ratio measured by inductively coupled plasma quadrupole mass spectrometry in the bio-accessible fractions from wheat, Miswak toothbrush (also used as chewing stick) and Miswak fruit. These samples were obtained for the in vitro batch and on-line leaching methods that mimic the human gastrointestinal tract by sequentially using artificial saliva, gastric juice and intestinal fluid for extraction. The two methods provided similar results according to a Student’s t-test at the 95% confidence level. Significant (p < 0.05) differences in 206Pb/207Pb were noted at the 95% confidence level in different artificial body fluids. Except for unpolluted Miswak toothbrush and Miswak fruit, which only contained geogenic Pb, the samples contained a mixture of geogenic and anthropogenic Pb, with bio-accessible Pb in saliva being mainly from a geogenic source, whereas bio-accessible Pb in the stomach and intestinal fluids was mainly from anthropogenic sources. Despite the fact that leaded petrol was phased out in Saudi Arabia in 2001, a Miswak toothbrush collected on the side of a busy road after exposure for only a few days and Safeer wheat were still being contaminated with Pb and had an isotopic composition matching that of Pb added to petrol. The 208Pb/206Pb isotopic ratio for gastric bio-accessible Pb also matched that reported in tetraethyllead. The 206Pb/207Pb isotopic ratios of intestinal bio-accessible Pb from Qassim wheat and Safeer wheat point to coal combustion as the source. Overall, these results highlight the need for continued Pb monitoring and the value of examining bio-accessible fractions periodically to identify Pb sources.
      2021,42(5),278-281
      DOI: 10.46770/AS.2021.103
      Abstract:
      Clinimetallomics is proposed as a branch of metallomics that focuses on the study of the metallome in clinical samples of urine, blood, and tissues. As the clinical diagnosis of arsenic poisoning is mainly based on the concentration of total arsenic in urine, the toxicity of arsenic varies greatly in different speciation. Analysis of arsenic speciation with excessive total arsenic in urine can provide a basis for precise treatment. It can also be used to understand the fate of arsenic in the body of patients with arsenic poisoning after treatment with sodium dimercaptopropane sulfonate. In this study, a HPLC-ICP-MS method was established for the determination of arsenic species in urine samples from patients diagnosed with arsenism. Use the established method to detect urine samples, which can be directly assayed after simple sample dilution with 20 mmol/L EDTA-2Na. With the concentration of arsenic speciation in the range of 1.0~100.0 ng/mL, the linear correlation coefficient was higher than 0.99996. The recoveries were between 91.1 % and 111 %. The precision of the concentration was less than 5.00 % and the detection limit was between 1.42 ng/mL and 1.86 ng/mL. This method can be applied to arsenic speciation in the urine of healthy people, in patients treated for arsenic poisoning, and in patients diagnosed with arsenism.
      2021,42(5),282-293
      DOI: 10.46770/AS.2021.703
      Abstract:
      The Fe isotope ratios can be a useful tracer of geochemistry, biogeochemistry, and the environmental redox state. In this study, we investigated the feasibility of Fe isotopic analysis in Fe-dominated minerals by 193 nm excimer ns laser ablation combined with Nu Plasma 1700 high resolution MC-ICP-MS without matrix-match calibration. Several important instrument parameters were investigated, such as the effect of the addition of nitrogen gas and water vapor, the effects of analytical parameters such as ablation mode, laser fluence, pulse repetition rate, spot size on Fe isotopic mass bias during analysis were investigated as well. The results showed that the effects of ablation mode, spot size, laser pulse repetition rate, and line scan speed can be neglected, while laser fluence and matrix effects had significant influence on the Fe isotopic mass bias at dry plasma condition. These problems can be minimized using consistent lower fluence (1.5?3.5 J·cm-2), as well as the wet plasma conditions can significantly reduce the matrix effect in Fe isotopic analysis. Fortunately, with the water vapor and nitrogen gas addition after the ablation cell, an accurate and precise Fe isotope in pyrite, manganite, hematite, and chalcopyrite analysis by ns-LA-MC-ICP-MS can be achieved with non-matrix-matched calibration. The obtained accuracy and reproducibility of the in situ determinations of δ56FeIRMM-014 were both better than ± 0.10‰ (2 SD). This study indicated that there was a serious matrix effect in the Fe isotopic analysis of Fe-dominated minerals by ns- LA-MC-ICP-MS, and nitrogen gas mixed with water vapor-assisted ns- LA-MC-ICP-MS were an appealing option for the in situ Fe isotope analysis of Fe-dominated minerals with non-matrix-matched calibration.
      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.
      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.
      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.
      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.
      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.
      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.
      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.
      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.
      Abstract:
      Theory, design, and operation of a dynamic reaction cell for ICP-MS

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