Showing papers in "Journal of Analytical Atomic Spectrometry in 2011"
TL;DR: Iolite is a non-commercial software package developed to aid in the processing of inorganic mass spectrometric data, with a strong emphasis on visualisation versus time of acquisition, to provide a powerful framework for data processing and interpretation, while giving users the ability to implement their own data reduction protocols.
Abstract: Iolite is a non-commercial software package developed to aid in the processing of inorganic mass spectrometric data, with a strong emphasis on visualisation versus time of acquisition. The goal of the software is to provide a powerful framework for data processing and interpretation, while giving users the ability to implement their own data reduction protocols. It is intended to be highly interactive, providing the user with a complete overview of the data at all stages of processing, and allowing the freedom to change parameters and reprocess data at any point. The program presents a variety of windows for the selection and viewing of data versus time, as well as features for the generation of X-Y plots, summary reports and export of data. In addition, it is capable of generating X-Y images from laser ablation rasters, and combining information from up to four separate elemental concentrations (intensities of red, green and blue, and the z-axis) in a false-colour three-dimensional image. By virtue of its underlying computing environment—Igor Pro—Iolite is capable of processing very large datasets (i.e., millions of timeslices) rapidly, and is thus ideal for the interrogation of multi-hour sessions of laser ablation data that can not be easily manipulated in conventional spreadsheet applications, for example. It is also well suited to multi-day sessions of solution-mode inductively-coupled plasma mass spectrometer (ICPMS) or thermal ionisation mass spectrometer (TIMS) data. A strong emphasis is placed on the interpolation of parameters that vary with time by a variety of user selectable methods including smoothed cubic splines. Data are processed on a timeslice-by-timeslice basis, allowing outlier rejection and calculation of statistics to be employed directly on calculated results. This approach can reduce the risk of processing biases associated with the manipulation of integrated datasets, while also allowing the implementation of more complex data reduction methods.
2,512 citations
TL;DR: In this paper, a methodological approach for identification, characterization and determination of mass and number concentration of dissolved Ag(I) and silver nanoparticles at environmentally relevant concentrations is presented, where the frequency plots with respect to the intensity measured for each pulse show independent distributions for dissolved silver and Ag nanoparticles, whose profiles are also different.
Abstract: The different behaviours of dissolved silver and silver nanoparticles under ICP-MS single particle detection conditions have been used to differentiate directly between both forms of silver in aqueous samples. Suspensions containing silver nanoparticles at number concentrations below 109 L−1 and/or dissolved Ag(I) are introduced into the ICP-MS by conventional pneumatic nebulization and measured with a time resolution of 5 ms. Each silver nanoparticle is converted in the ICP into a packet of ions, which are detected as a single pulse, whose intensity is proportional to the number of silver atoms in the nanoparticle, whereas dissolved silver produces pulses of averaged constant intensity. The frequency plots with respect to the intensity measured for each pulse show independent distributions for dissolved silver and silver nanoparticles, whose profiles are also different (Poisson and lognormal, respectively). Size limits of detection for pure Ag nanoparticles of 18 nm, equivalent to a silver mass of 32 ag, were obtained. Number concentration limits of detection of 1 × 104 L−1 can be achieved. A methodological approach for identification, characterization and determination of mass and number concentration of dissolved Ag(I) and silver nanoparticles at environmentally relevant concentrations is presented.
331 citations
TL;DR: An overview of publications focussed on the period since 2000 and outlining modern methods of sample preparation as well as advanced techniques for determination of rare earth elements (REE) in various matrices is presented in this article.
Abstract: An overview of publications focussed on the period since 2000 and outlining modern methods of sample preparation as well as advanced techniques for determination of rare earth elements (REE) in various matrices is presented in this paper. The review discusses the problems of REE determination in diverse samples i.e. from biological through environmental and geological to advanced materials. The preferable procedure of sample digestion and the most frequently applied methods of sample preparation for determination of trace elements are discussed in this paper. The case of direct analysis of samples for REE determination is also discussed. The review outlines determination of REE employing many techniques such as, inter alia, flame or graphite furnace atomic absorption spectrometry, atomic absorption with chemical vapor generation, X-ray fluorescence spectrometry, inductively coupled plasma optical emission spectrometry, inductively coupled plasma mass spectrometry and neutron activation analysis. This article summarizes and classifies materials in which rare earth elements are present, main places of their occurrence and the methods of their analysis.
156 citations
TL;DR: In this article, three self-built scanning macro-XRF instruments are compared in terms of sensitivity and limits of detection, which includes a discussion of the use of polycapillary optics and pinhole collimators as beam defining devices.
Abstract: Elemental distribution maps are of great interest in the study of historical paintings, as they allow to investigate the pigment use of the artist, to image changes made in the painting during or after its creation and in some cases to reveal discarded paintings that were later over painted. Yet a method that allows to record such maps of a broad range of elements in a fast, non-destructive and in situ manner is not yet commonly available; a dedicated mobile scanning XRF instrument might fill this gap. In this paper we present three self-built scanning macro-XRF instruments, each based on the experience gained with its precursor. These instruments are compared in terms of sensitivity and limits of detection, which includes a discussion of the use of polycapillary optics and pinhole collimators as beam defining devices. Furthermore, the imaging capabilities of the instruments are demonstrated in three exemplary cases: (parts of) historical paintings from the 15th to the 19th century are examined. These cases illustrate the value of element specific distribution maps in the study of historical paintings and allow in the case of Vincent van Gogh's “Patch of Grass” a direct comparison between in situ and synchrotron based scanning macro-XRF.
146 citations
TL;DR: In this article, a commercial micro-droplet generator was used to generate 30-40 µm droplets with nearly 100% efficiency and high uniformity to the inductively coupled plasma optical emission spectrometer (ICP-OES).
Abstract: Recently, first analyses of single sub-micrometre particles, embedded in liquid droplets, by inductively coupled plasma optical emission spectrometry (ICP-OES) with a size-equivalent detection limit of several hundred nanometres were reported. To achieve lower detection limits which might allow for the analysis of particles in the nanometre size range a more sensitive technique such as mass spectrometry (MS) is required. Various modifications of particle delivery and data acquisition systems commonly used were carried out to install a setup adequate for ICP-MS detection. These modifications enabled us to supply droplets generated by a commercial microdroplet generator (droplet size: 30–40 µm) with nearly 100% efficiency and high uniformity to the ICP. Analyses were performed using both standard solutions of dissolved metals at concentrations of 1 (Ag), 2 (Au), 5 (Au), or 10 (Cu) mg L−1 and highly diluted suspensions of gold and silver nanoparticles with sizes below 110 nm. In doing so, detection efficiencies of 10−6 counts per atom could be achieved while size-related limits of quantification were found to be 21 nm and 33 nm for gold and silver, respectively. Furthermore, the advantages of utilizing microdroplet generators vs. conventional nebulizers for nanoparticle analyses by ICP-MS are discussed.
143 citations
TL;DR: In this paper, the relative and absolute Mg-isotope composition of a number of terrestrial and extraterrestrial materials, including international reference rock standards as well as pure Mg standards, olivine crystals separated from a mantle-derived spinel lherzolite (J12Olivine), one enstatite chondrite, a martian shergottite, and sea water samples, were measured using high-resolution multiple collector inductively coupled plasma source mass spectrometry (HR-MC-ICPMS).
Abstract: We report novel methods for the chemical purification of Mg from silicate rocks by ion-exchange chromatography, and high-precision analysis of Mg-isotopes by high-resolution multiple collector inductively coupled plasma source mass spectrometry (HR-MC-ICPMS). Using these methods, we have measured the relative and absolute Mg-isotope composition of a number of terrestrial and extraterrestrial materials, including international reference rock standards as well as pure Mg standards, olivine crystals separated from a mantle-derived spinel lherzolite (J12 olivine), one enstatite chondrite, a martian shergottite and sea water samples. Repeated analyses of terrestrial and extraterrestrial samples demonstrate that it is possible to routinely measure the relative Mg-isotope composition of silicate materials with an external reproducibility of 2.5 and 20 ppm for the μ26Mg* and μ25Mg values, respectively (μ notation is the per 106 deviation from a reference material). Analyses of bulk mantle-derived rocks as well as a martian shergottite and an enstatite chondrite define a restricted range in μ25Mg of −120 ± 28 ppm (2sd) relative to the DSM-3 reference standard (μ25,26Mg = 0), suggesting that the Mg-isotope composition of inner solar system bulk planetary materials is uniform within the resolution of our analyses. We have determined the absolute Mg-isotope composition of the J12 olivine, two CI chondrites as well as the DSM-3 and Cambridge-1 reference standards using a mixed 26Mg-24Mg double-spike. The differences between the absolute 25Mg/24Mg ratios of the various materials analyzed relative to the DSM-3 standard are in excellent agreement with results obtained by the sample-standard bracketing method. Based on the averages obtained for the J12 olivine separates, we estimate the absolute Mg-isotope composition for Earth's mantle – and hence that of the bulk silicate Earth – to be 25Mg/24Mg = 0.126896 ± 0.000025 and 26Mg/24Mg = 0.139652 ± 0.000033. Given the restricted range of μ25Mg obtained for bulk planetary material by the sample-standard bracketing technique and the excellent agreement between the data obtained by the relative and absolute methods, we propose that these new values represent the absolute Mg-isotope composition of the bulk inner solar system. Using the absolute Mg-isotope composition of the J12 olivine, we calculate the isotopic abundances of Mg as 24Mg = 0.789548 ± 0.000026, 25Mg = 0.100190 ± 0.000018, and 26Mg = 0.110261 ± 0.000023. Based on this result, we have calculated an atomic weight for Mg of 24.305565 ± 0.000045, which is marginally heavier than previous estimates but a factor of 10 more precise.
130 citations
TL;DR: In this article, a method for quasi-simultaneous determination of U-Pb ages and Hf isotope compositions on a single zircon spot is developed, by use of a multiple-collector ICPMS coupled with an excimer laser-ablation system.
Abstract: A method for quasi-simultaneous determination of U-Pb ages and Hf isotope compositions on a single zircon spot is developed, by use of a multiple-collector ICPMS coupled with an excimer laser-ablation system. The ICPMS used in this study is equipped with variable zoom lens to change the dispersion of the analyzer and bring ion beams into the collector coincidentally. This feature allows rapid switching between U-Pb and Hf collector configuration, which is used to quasi-simultaneously determine the zircon U-Pb and Hf isotope compositions. The analytical results on three reference zircon standards, 91500, CZ3 and Plesovice and one nature zircon sample, agree with literature/known values, thereby demonstrating feasibility of the method.
116 citations
TL;DR: In this paper, the laser-induced elemental fractionation for 63 selected isotopes are negligible at the spot sizes of 160-44 µm, but increase significantly with decreasing spot sizes from 44 µm to 32 µm and 16 µm.
Abstract: The greatest strength of the LA-ICP-MS technique is its application to microsampling in which extremely small pits are obtained. The results of this study highlight some significant different laser-induced fractionations between widely used external reference materials NIST SRM 610–614 and natural silicate reference materials (e.g., USGS reference glasses (GSE-1G, GSD-1G), MPI-DING glasses, USGS basalt glasses and zircon reference material GJ-1) at high spatial resolution analysis. For the sample matrices and analytical conditions used in this study, the laser-induced elemental fractionations for 63 selected isotopes are negligible at the spot sizes of 160–44 µm. However, the laser-induced elemental fractionations of Li, Na, Si, K, V, Cr, Mn, Fe, Co, Ni, Cu, Rb, Cs and U (with respect to Ca) increase significantly with decreasing spot sizes from 44 µm to 32 µm, 24 µm and 16 µm in these natural silicate reference materials. Unlike in these sample matrices, laser-induced elemental fractionations of these elements in NIST SRM 610–614 are unique in that they are almost not affected by the change of spot sizes from 44 to 32 to 24 µm, with only slight increase at the spot sizes of 16 µm. The much less significant laser-induced elemental fractionation in NIST SRM 61X in comparison with other natural silicate materials makes them not ideal as external reference materials at high spatial resolution analysis. Alternatively, this NIST SRM 61X-specific matrix effect for Li, Na, K, V, Cr, Mn, Fe, Co, Ni, Cu, Rb, Cs and U can be minimized by using Si for internal standardization. U and Pb in zircon GJ-1 are exceptions, which are zircon-specific.
114 citations
TL;DR: In this paper, the authors used a Partial Least Square (PLS1) regression to determine the isotope ratio between 0 and 1 mass fraction for hydrogen and uranium isotope shift lines.
Abstract: Laser-Induced Breakdown Spectroscopy (LIBS) is currently a subject of great interest in spectroscopy and is being considered for the design of a field portable unit for nuclear safeguard inspection, because it allows a high level of portability and versatility while identifying the elements and materials of interest. Field portable technologies and methods are sought to provide simple, inexpensive, and fast analysis of materials in the mining, construction, and other industries. However, the level of portability needed for this particular application imposes some restrictions on the choice of many of the core components used in a low cost LIBS handheld sensor. This means that relatively low-performance components, such as a low-energy laser source and a low cost, low resolution spectrometer, must be considered to fulfil these conditions. In addition, the market price of such a portable device should be as low as possible to increase the breadth of potential end users and allow the deployment of multiple units for security enhancement. The present paper describes the determination of isotope ratios using Laser-Induced Breakdown Spectroscopy in air at atmospheric pressure for partially resolved uranium-235/uranium-238 and hydrogen/deuterium isotope shift lines in such conditions. Using a Partial Least Square (PLS1) regression, it is possible to build a model that enables the accurate determination of the isotopic ratio under conditions where the application of traditional univariate approaches for hydrogen and uranium would not be achievable without the use of ultra high resolution spectrometer. In addition, the application of PLS1 regression to determine the uranium-235/uranium-238 and deuterium/hydrogen isotopic ratios between 0 and 1 mass fraction was also successfully demonstrated. The performance obtained with such a LIBS sensor configuration demonstrates the possibility of integrating all of the required components in a small portable handheld system.
106 citations
TL;DR: In this paper, the authors review the general characterization of nano-objects, especially engineered nanoparticles (ENPs), and discuss analytical techniques commonly used for their determination, including the use of inductively coupled plasma (ICP) technique for the determination of ENPs itself or when applied in a large variety of products including possible release during use.
Abstract: This article reviews the general characterization of nano-objects, especially engineered nanoparticles (ENPs) and discusses analytical techniques commonly used for their determination. The main aspect of this review covers the use of the inductively coupled plasma (ICP) technique for the determination of ENPs itself or when applied in a large variety of products including possible release during use. Beside various applications by direct determination or analysis after suitable digestion also novel approaches e.g. single particle introduction, and hyphenated techniques such as field flow fractionation (FFF) or size exclusion coupled to plasma spectrometry are discussed in detail. Finally, an overview of the state-of-the-art possibilities for quality control related to the atomic spectrometric analysis of nanoparticles is given.
99 citations
TL;DR: The twenty-sixth annual review published in JAAS on the application of atomic spectrometry to the chemical analysis of environmental samples as discussed by the authors refers to papers published approximately between September 2009 and August 2010 and continues the series of Atomic Spectrometry Updates in Environmental Analysis that should be read in conjunction with other related reviews in the series.
Abstract: This is the twenty-sixth annual review published in JAAS on the application of atomic spectrometry to the chemical analysis of environmental samples. This Update refers to papers published approximately between September 2009 and August 2010 and continues the series of Atomic Spectrometry Updates in Environmental Analysis that should be read in conjunction with other related reviews in the series.2–6 In the analysis of air, work is ongoing in developing new and existing air sampler devices with an increasing focus on sampling nanoparticles. Determination of mercury in the atmosphere remains a focus for many research groups and this year has seen a renewed interest in sampling and analysis of respirable silica. There is a growing interest in measuring emissions from transport sources such as aviation and shipping. In the field of water analysis, as in previous years, the main areas of activity are the development of preconcentration and extraction procedures and elemental speciation protocols. In the field of soil, plant and related materials analysis, the past year has seen a marked increase in publications featuring LIBS. The technique now appears well established for screening purposes but has not yet convinced detractors of its suitability for use in quantitative multi-element analysis. There is a growing body of literature examining species stability during sample pre-treatment and extraction. Slurry sampling has experienced renewed interest this year. In the field of geological analysis, as in previous years, considerable effort is being spent not only on the production, characterization and certification of new geological reference materials, but also on enhancing the certification of existing reference materials and the development of reference materials with assigned elemental isotopic ratios. Laser ablation continues to go from strength to strength in being adopted as a solid sampling tool within the geochemical community with a growing interest in coupling laser ablation systems to multicollector ICP-MS systems for in situ isotopic analysis. Feedback on this review is most welcome and the lead author can be contacted using the email address provided.
TL;DR: In this paper, a new protocol was presented for precise measurements of titanium isotopes in natural samples, which was separated via ion-exchange and extraction chromatography in two stages and revealed a linear correlation between isotope anomalies of two Ti nuclides in bulk meteorites.
Abstract: A new protocol is presented for precise measurements of titanium isotopes in natural samples. Titanium was separated via ion-exchange and extraction chromatography in two stages. Tests on Ti standard solutions show that isobaric interferences from Ca, V, and Cr can be adequately corrected, as long as these elements are present at atomic ratios of Ca/Ti < 20, V/Ti < 2, and Cr/Ti < 0.1. Furthermore, Zr2+ and Mo2+ have no influences on Ti+ signals when atomic ratios of Zr/Ti < 0.002 and Mo/Ti < 0.04. Compared with these correction limits, the purified solutions have corresponding ratios several orders of magnitude lower, indicating that the chemical separation technique is effective. This newly developed method has been successfully applied to geostandards and a wide variety of bulk meteorites. Our results are in good agreement with the data from Trinquier et al. (Science, 2009, 324, 374–376)1 and reveal a linear correlation between isotope anomalies of two Ti nuclides in bulk meteorites. The correlation reflects incomplete mixing of the carrier phases for Ti isotope anomalies before bulk meteorite formation.
TL;DR: A review of recent literature focused on iodine determination/speciation in environmental, biological and clinical materials is provided in this paper, which covers the different sample pre-treatments to extract total iodine, as well as specific iodinated forms, and the most used analytical techniques for assessing total iodine.
Abstract: A review of recent literature focused on iodine determination/speciation in environmental, biological and clinical materials is provided. The review covers the different sample pre-treatments to extract total iodine, as well as specific iodinated forms, and the most used analytical techniques for assessing total iodine (cathodic stripping voltammetry, differential pulse voltammetry, neutron activation analysis, catalytic spectrophotometry, and atomic spectrometric techniques, mainly inductively coupled plasma-mass spectrometry) and iodine speciation (nonchromatographic methods, and mainly high performance liquid chromatography, gas chromatography and capillary electrophoresis coupled to electrochemical, UV spectrophotometric and mass spectrometric detection).
TL;DR: In this paper, the authors investigated the signal response variations under different laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) operating conditions to identify important factors for selecting an internal standard (IS) for quantitative elemental bio-imaging.
Abstract: Element response variations under different laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) operating conditions were investigated to identify important factors for selecting an internal standard (IS) for quantitative elemental bio-imaging. Analytes covering a range of atomic masses and first ionisation potentials (FIP) were selected to investigate the signal response variation with changes in laser spot diameter, mass bias and cell sampling position. In all cases, an IS improved experimental precision regardless of a close match in element mass or FIP but optimal analyte/IS combinations depended on the difference in masses of the analyte and IS. Particular attention was paid to 13C as this isotope is typically used as an IS in elemental bio-imaging applications. Despite its non-ideal IS characteristics (often different mass and FIP to many analytes), possibility of abundance sensitivity effects and poor signal-to-background ratio, 13C was a suitable IS candidate exhibiting a linear response with respect to the mass ablated, apparent independence from the high abundance of the adjacent 14N mass peak and effective analyte normalisation after background subtraction as long as the 13C signal from the sample was at least 6% of the gross signal.
TL;DR: The modified total evaporation (MTE) method as discussed by the authors was proposed for isotopic analysis of uranium samples by multi-collector thermal ionization mass spectrometry (TIMS), with high analytical performance and designed in a more user-friendly and routinely applicable way.
Abstract: A new version of the “modified total evaporation” (MTE) method for isotopic analysis of uranium samples by multi-collector thermal ionization mass spectrometry (TIMS), with high analytical performance and designed in a more user-friendly and routinely applicable way, is described in detail. It is mainly being used for nuclear safeguards measurements, but can readily be applied in other scientific areas like geochemistry. The development of the MTE method was organized in collaboration of several “key nuclear mass spectrometry laboratories”, namely the New Brunswick Laboratory (NBL), the Safeguards Analytical Laboratory (SAL, now SGAS—Safeguards Analytical Services) of the International Atomic Energy Agency (IAEA), the Institute for Transuranium Elements (ITU/JRC), and the Institute for Reference Materials and Measurements (IRMM/JRC), with IRMM taking the leading role. Due to the use of the “total evaporation” (TE) principle the measurement of the “major” ratio n(235U)/n(238U) is routinely being performed with an accuracy of 0.02%. In contrast to the TE method, in the MTE method the total evaporation process is interrupted on a regular basis to allow for correction for background from peak tailing, internal calibration of a secondary electron multiplier (SEM) detector versus the Faraday cups, peak-centering, and ion source re-focusing. Therefore, the most significant improvement using the MTE method is in the measurement performance achieved for the “minor” ratios n(234U)/n(238U) and n(236U)/n(238U). The n(234U)/n(238U) ratio is measured using Faraday cups only with the result that the (relative) measurement uncertainty (k = 2) is better than 0.12%, which is an improvement by a factor of about 5–10 compared to TE measurements. Furthermore, the IAEA requirement for the “measurement performance”, defined here as the sum of the (absolute) deviation of the measured from the true (certified) value plus the (absolute) measurement uncertainty (k = 2), for n(236U)/n(238U) ratio measurements is 1 × 10−6, but the MTE method provides a measurement performance which is, depending on the ratio, by several orders of magnitude superior compared to this limit and to the TE method. For routine MTE measurements a detection limit of 3 × 10−9 was achieved using an SEM detector for detecting the isotope 236U. The MTE method is now routinely being used at all collaborating laboratories with the hope that more laboratories will implement this capability in the future as well. Additional applications for the MTE method are presented in this paper, e.g., for absolute Ca isotope measurements.
TL;DR: In this paper, the authors established a highly reproducible analysis of Sm, Nd and Nd isotopic compositions in geological samples by isotope dilution analysis with MC-ICP-MS.
Abstract: In this work, we established a highly reproducible analysis of Sm, Nd concentrations and Nd isotopic compositions in geological samples by isotope dilution analysis with MC-ICP-MS. This technique is superior in terms of the analytical reproducibility or rapidity of analysis compared with quadrupole ICP-MS or with thermal ionization mass spectrometry (TIMS) isotope dilution techniques. Samples were spiked with 149Sm–150Nd enriched tracer and then digested by a commonly used HF, HNO3 and HClO4 acid protocol. The bulk rare earth elements (REEs) were separated from the sample on a standard cation exchange resin, and further purified on Eichrom Technologies Ln Resin, to obtain Sm and Nd fractions prior to mass spectrometric measurements. Replicate analyses of international certified reference materials (CRMs) demonstrate that our obtained 147Sm/144Nd and 143Nd/144Nd isotopic ratios are in good agreement with previously published values from isotope dilution methods. In addition to determining the concentrations of Sm and Nd, the Nd isotopic composition can be measured simultaneously during Nd isotope dilution run. Additionally, a mineral Sm-Nd isochronal age that is identical to, within error, a U-Th-Pb zircon age for the same rock is further measured and validates the robustness of the present protocol. Therefore, the high actual sample throughput inherent to the MC-ICP-MS can be fully exploited for the determination of Sm and Nd concentrations and Nd isotopic compositions.
TL;DR: In this paper, a method for the separation of small quantities of Cr from carbonate material and for the analysis of stable Cr isotopes in carbonates by MC-ICP-MS is presented.
Abstract: Techniques for the separation of small quantities of Cr from carbonate material and for the analysis of stable Cr isotopes in carbonates by MC-ICP-MS are presented in this study. In comparison with previously published methods, we have developed a one-step Cr separation procedure that is relatively simple, and has a low blank (0.12–0.20 ng). Moreover, careful optimisation of the desolvating sample introduction system allows a significant increase in the sensitivity of our MC-ICP-MS technique compared to previous studies. Instrumental mass bias effects and fractionation of Cr isotopes during Cr separation are corrected using a carefully optimised 50Cr–54Cr double-spike method. Novel numerical simulations demonstrate that the effects of potential isobaric interferences from Ti, Fe and V are negligible, even if they are isotopically fractionated. Small deviations in the δ53Cr value of the NBS 979 standard between different analytical sessions are due to small deviations from exponential mass fractionation behaviour. The long-term reproducibility of δ53Cr for a spiked NBS 979 Cr isotope reference material is ±0.031‰ (2 S.D., n = 147). Analyses of carbonates reveal that they have δ53Cr values of 0.747 to 1.994‰, distinctly heavier than continental crust and the terrestrial mantle. The carbonates record Cr isotopic fractionation that may be used to understand redox reactions in the oceans. Although this study focuses on carbonate samples, our mass spectrometry technique can be applied to the analysis of any samples with low levels of Cr, including river waters and seawater.
TL;DR: In this paper, the Taylor expansion was applied near the standard plasma condition to obtain the standard state value of the characteristic line intensity from theory, and the results showed that measurement precision and accuracy can be greatly improved by the application of this normalization method in measuring the Cu concentration for 29 brass alloy samples.
Abstract: Relatively high uncertainty (or low repeatability) is one of the main bottlenecks for wide application of LIBS quantitative measurements. The change of plasma temperature and electron number density from pulse to pulse weakens the correlation between the ablation mass and total or part of the spectral area for the same sample, making the normally applied normalization method not effective enough for uncertainty reduction. In the present work, it was assumed that there existed a standard state for samples with similar matrix, where there is a standard plasma temperature, electron number density, and total number density of the element of interest. Therefore, Taylor expansion can be applied near the standard plasma condition to obtain the standard state value of the characteristic line intensity from theory. The temperature variation was regarded to be proportional to the variation of the logarithm of the ratio of two spectral line intensities of the interested element, the variation of electron number density was regarded to be proportional to the variation of the full width at half maximum (FWHM), and the variation of total number density was regarded to be proportional to the variation of the sum of the multiple spectral line intensities of the measured element. Based on these assumptions, the calibration model was established. The results show that measurement precision and accuracy can be greatly improved by the application of this normalization method in measuring the Cu concentration for 29 brass alloy samples. The average relative standard deviation (RSD) value, the coefficient of determination (R2), the root mean square error of prediction (RMSEP), and average value of the maximum relative error were 2.92%, 0.99, 1.46%, 8.42%, respectively, while the values for normalization with the whole spectrum area were: 8.61%, 0.95, 3.28%, 29.19%, respectively, showing significant improvement.
TL;DR: In this paper, the applicability of the NIST SRM 610, the USGS GSE-1G, and the Nist SRM 2782 reference materials (RMs) as external standards and developed a reliable method for LA-ICP-MS analysis of magnetite.
Abstract: Magnetite (Fe3O4) is a common accessory mineral in many geologic settings. Its variable geochemistry makes it a powerful petrogenetic indicator. Electron microprobe (EMPA) analyses are commonly used to examine major and minor element contents in magnetite. Laser ablation ICP-MS (LA-ICP-MS) is applicable to trace element analyses of magnetite but has not been widely employed to examine compositional variations. We tested the applicability of the NIST SRM 610, the USGS GSE-1G, and the NIST SRM 2782 reference materials (RMs) as external standards and developed a reliable method for LA-ICP-MS analysis of magnetite. LA-ICP-MS analyses were carried out on well characterized magnetite samples with a 193 nm, Excimer, ArF LA system. Although matrix-matched RMs are sometimes important for calibration and normalization of LA-ICP-MS data, we demonstrate that glass RMs can produce accurate results for LA-ICP-MS analyses of magnetite. Cross-comparison between the NIST SRM 610 and USGS GSE-1G indicates good agreement for magnetite minor and trace element data calibrated with either of these RMs. Many elements show a sufficiently good match between the LA-ICP-MS and the EMPA data; for example, Ti and V show a close to linear relationship with correlation coefficients, R2 of 0.79 and 0.85 respectively.
TL;DR: In this article, the authors introduced a low temperature argon plasma from dielectric barrier discharge (DBD) for the determination of mercury in certified reference water sample and mineral water samples, and achieved a limit of detection of 0.090 μg L−1 and a precision of 2.1% RSD at a concentration of 10 μg l−1.
Abstract: Mercury solution without or with formic acid was introduced into a low temperature argon plasma from dielectric barrier discharge (DBD). Mercury vapor generated in the DBD was separated from the liquid phase and finally swept into an inductively coupled plasma optical emission spectrometer (ICP-OES) for determination. The optimum conditions for the proposed technique and operation of the ICP-OES, as well as interferences from concomitants, were investigated in detail. It was found that the vapor generation efficiency of mercury could be significantly enhanced with the addition of formic acid. However, the efficiency was reduced sharply in the presence of chloride ions or oxidizing substances of high concentration. Under the optimized conditions, a limit of detection of 0.090 μg L−1 and a precision of 2.1% RSD at a concentration of 10 μg L−1 were achieved by the proposed method. The new DBD-induced mercury vapor generation provides several advantages including low power consumption (<25 W), green analytical chemistry, cost-effectiveness, smaller size, long operation lifetime, and ease of on-line operation. The methodology has been successfully applied to the determination of mercury in a certified reference water sample and mineral water samples.
TL;DR: In this paper, the authors used laser induced breakdown spectroscopy (LIBS) for the analysis and characterization of a broad variety of objects of cultural heritage especially bio-archeological samples such as calcified tissues.
Abstract: Laser Induced Breakdown Spectroscopy (LIBS) has emerged in the past decade as a very promising technique for the analysis and characterization of a broad variety of objects of cultural heritage especially bio-archeological samples such as calcified tissues namely teeth and bones. The most important advantages of LIBS from the archeological point of view are its quasi nondestructive nature and its potential for performing in situ measurements. In the present work human calcified tissue samples of recent and archeological bones have been studied via the LIBS technique. The old samples were from three different ancient Egyptian dynasties representing the middle kingdom (1980–1630 BC), the 2nd intermediate period (1630–1539/23 BC) and the pre-Roman period (664 BC). Elements normally used to study dietary habits such as strontium, barium, aluminium and lead were analyzed in the obtained LIBS spectra and the interferences of postmortem or diagenic effects due to the burial place were investigated viaLIBS analysis of soil samples taken from the same locations where the archeological bones have been buried. The obtained results have demonstrated evidently that conclusions about dietary habits must take into account postmortem effects such as biological degradation and environmental leaching (especially from the surrounding soil). Study of CN and C2 molecular bands in the obtained LIBS spectra of the bones revealed that these bands have strong intensities in recent bones spectra contrary to the archaeological ones. This is attributed to the degradation of the tissues and has been confirmed by following up calcium to phosphorus ratios in different bone samples.
TL;DR: In this paper, a broad set of coal samples with different amounts of volatile matter content were tested by LIBS, and the experimental results derived from the correlation were consistent with those from standard analysis procedures (thermo-gravimetric analysis, TGA).
Abstract: Volatile matter content is an important index of coal quality characteristics. Laser-induced breakdown spectroscopy (LIBS) is a promising analytical spectroscopy technique. In this paper, a broad set of coal samples with different amounts of volatile matter content were tested by LIBS. Analytical methods with partial correlation and principal component regression were used to extract related LIBS spectral information based on coal structure, which indicates a strong correlation with the content of volatile matter to establish the calibration model. The experimental results derived from the correlation are consistent with those from standard analysis procedures (thermo-gravimetric analysis, TGA). This demonstrates that LIBS is a viable approach to directly determine the volatile content rather than indirect ultimate analysis.
TL;DR: In this article, a 3D object detection combined with a laser-induced breakdown spectroscopy (LIBS) setup is presented for the analysis of moving particle streams in industrial recycling processes.
Abstract: In industrial recycling processes secondary metals need to be separated by material grades before they can be further processed. The identification and separation into different material classes lead to higher value-added industrial feedstock and prevent downgrading processes. Secondary raw materials can be used more efficiently resulting in an increased use of waste products in resource-intensive production processes. Laser-induced breakdown spectroscopy (LIBS) offers a contact free, multi-elemental and fast method for the inline quantitative analysis of single objects in moving particle streams. The LIBS method presented in this paper is based on a 3D object detection combined with a scanning LIBS setup. The optical system consists of a pulsed Nd:YAG laser running at 40 Hz, delivering a 200 mJ double pulse for plasma generation. A high performance three axis galvo-scanner guides the laser beam onto single pieces moving at 3 m s−1 through a measuring volume of 600 × 600 × 100 mm3 with a precision of ±1.5 mm. Twenty channels of a high resolution Paschen–Runge spectrometer are simultaneously processed within a few microseconds enabling multi-elemental analysis of different aluminium (Al) alloys. A dimensionless figure of merit is introduced for the evaluation of the analytical performance. Sorting measurements of Al post-consumer scrap charges, consisting of wrought and cast alloys were carried out. After discarding 20% of the data as outliers low and high silicon alloyed Al pieces were identified with a correctness of >96%. In a second sorting scenario the analytical discrimination of 8 different Al alloys of production scrap, requiring high analytical precision, is investigated. A mean identification correctness of wrought Al alloys >95% is demonstrated successfully for the first time.
TL;DR: In this paper, the sulfate matrix effect is solved by adding to both sample and bracketing standard sulfuric acid in large excess compared to the naturally occurring SO42−, which can also induce a major Si isotopic bias when analysing river waters.
Abstract: One of the most widely used sample preparation methods for Si isotopic analyses (δ30Si and δ29Si) is based on cationic chromatography, which does not remove anions from samples. Although it was first thought that the presence of anions in natural concentrations does not distort the isotopic analyses, it has recently been shown that the presence of sulfate can induce a significant shift in isotopic ratio measurements above SO42−/Si ratios (wt) of 0.02. Here, we show that dissolved organic matter can also induce a major Si isotopic bias when analysing river waters. To overcome these non-spectral matrix effects we propose fast and reliable ways, tested on natural freshwater and rock digestion solutions. The sulfate matrix effect is solved by adding to both sample and bracketing standard sulfuric acid in large excess compared to the naturally occurring SO42−. The organic matrix is mineralized by the combined action of UV-C and ozone. We also provide the first δ30Si signature measurements of two common geostandards: SGR-1 (δ30Si = +0.03‰) and FeR-1 (δ30Si = −0.20‰).
TL;DR: In this paper, an ultrasensitive method for simultaneous determination of cytochrome c (cyt-c) and insulin was developed by combining aptamer-based bioassay and immunoassay, multielement-tagging and inductively coupled plasma mass spectrometry (ICP-MS).
Abstract: An ultrasensitive method for simultaneous determination of cytochrome c (cyt-c) and insulin was developed by combining aptamer-based bioassay and immunoassay, multielement-tagging and inductively coupled plasma mass spectrometry (ICP-MS). Aptamer-modified gold nanoparticles (apt-AuNPs) and antibody-modified silver nanoparticles (ab-AgNPs) were employed as specific element tags for cyt-c and insulin, respectively. The prepared surface-functionalized magnetic microparticles (MMPs) were used for efficient and fast magnetic separation. The bioassay conditions were carefully optimized, including the amount of MMPs, the concentration of AuNPs and AgNPs, and the reaction time. Under optimal conditions, the developed method gave a linear range of 0.1–20 nM for cyt-c and 0.2–40 nM for insulin, a detection limit (3s) of 1.5 fmol (30 pM in 50 μL) for cyt-c and 5.5 fmol (110 pM in 50 μL) for insulin. The precision (relative standard deviation) for six replicate determinations of cyt-c (0.6 nM) and insulin (2.0 nM) was 6.6%, and 6.0%, respectively. The present method exhibits good specificity with recoveries from 87% to 98% for spiked cyt-c and insulin in human serum samples. The methodology demonstrated here provides a new possibility for bioassays and clinical diagnoses, which has potential for simultaneous determination of two or more low-abundance biomarkers of interest via multi-element tags.
TL;DR: The use of iodine as an internal standard to correct for tissue inhomogeneities in LA-ICP-MS was investigated for the simultaneous detection of two tumor markers (Her 2 and CK 7) in breast cancer tissue.
Abstract: A new laser ablation (LA)-ICP-MS method for single cell and cell nucleus imaging was developed. Therein, iodine was employed as an elemental dye for fibroblast cells and for thin tissue sections. At an incubation time of 60 s, iodine is located mainly within the cell nuclei. This effect was illustrated in fibroblast cells, and iodine signal within the cell nucleus was as high as 5 × 104 cps at 4 μm laser spot size. The surrounding cytoplasm was iodinated as well, but to a lesser extent. The spatial resolution attained was sufficient to detect even smaller cell nuclei within a liver biopsy tissue. Furthermore, iodine was successfully employed for biomolecule labeling and we demonstrated that iodine signal increased with increasing thickness of a palatine tonsil tissue. Thus, the use of iodine as an internal standard to correct for tissue inhomogeneities in LA-ICP-MS was investigated for the simultaneous detection of two tumor markers (Her 2 and CK 7) in breast cancer tissue. Additionally, lanthanide background resulting from glass ablation can be corrected for by Eu standardization.
TL;DR: In this article, microwave-induced combustion (MIC) and microwave-assisted acid digestion (MW-AD) were evaluated for further As, Bi, Cd, Co, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Sr, Ti, V and Zn determination.
Abstract: In this work, sample preparation methods for polymer digestion based on microwave-induced combustion (MIC) and microwave-assisted acid digestion (MW-AD) were evaluated for further As, Bi, Cd, Co, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Sr, Ti, V and Zn determination by inductively coupled plasma mass spectrometry (ICPMS) and inductively coupled plasma optical emission spectrometry (ICPOES). Samples of low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET, colorless and green), polyetheretherketone (PEEK) and nylon 6,6 were digested using MIC and MW-AD in closed quartz vessels. The type and concentration of acids used for MIC were investigated and better results were achieved using a 4 mol l−1 HNO3 + 4 mol l−1 HCl solution. Microwave-assisted acid digestion was also evaluated for polymer digestion using concentrated acids. Both sample preparation methods were considered suitable for polymer digestion but MIC was preferable in view of the possibility of using diluted acids as absorbing solution and allowing higher sample mass to be digested and consequently better limits of detection. Residual carbon content in digests of polymers obtained by MIC was lower in comparison with the values obtained after MW-AD. Accuracy for all the analytes determined by ICPOES and ICPMS after MIC digestion was better than 95% (analysis of certified reference materials and by neutron activation analysis). It was possible to digest up to 8 samples by MIC in less time (in 25 min) in comparison with MW-AD (more than 50 min) and also using diluted acids (4 mol l−1 HNO3 and HCl) instead of concentrated acids.
TL;DR: A review of the most recent developments in multi-elemental analysis (Part A) and speciation analysis in plant science is presented in this paper, where the analytical developments have unravelled the functional roles of elements in plants science.
Abstract: Inductively coupled plasma-mass spectrometry (ICP-MS) is the state-of-the-art technique for multi-elemental analysis of plant tissue. It provides a powerful tool in functional genomics, linking altered elemental profiles of mutants with gene expression and function. In addition, with its unmatched sensitivity, ICP-MS enables characterization of the substrate specificity and regulation of membrane transport proteins. Digestion of plant tissue has traditionally represented a bottleneck due to the low capacity of commercially available equipment. However, recent developments in micro-scaled digestion, combined with semi-quantitative analysis and chemometrics, have enabled high-throughput multi-elemental profiling and multivariate classification of large sample sets, thereby supporting a range of new applications in molecular breeding, quality assessment and authenticity testing of plants. Novel hyphenated techniques based on liquid chromatography and ICP-MS (LC-ICP-MS) have significantly improved the understanding of elemental species and their importance for e.g. the bioactivity of metals in plants. Development of procedures for sample pre-treatment, extraction and multi-dimensional separation now allows characterization of important metallo-biomolecules in plants, such as the coordination complexes of phytochelatins, metallothioneins, nicotianamine and inositol phosphates. These are key ligands involved in ion homeostasis, translocation and long-term storage of elements. Much emphasis has also been given to studies of covalently bound Se and As species, primarily due to their impact on human health. LC-ICP-MS has extensively been complemented by molecular mass spectrometry for structural information of biologically relevant species. This review covers the most recent developments in multi-elemental analysis (Part A) and speciation analysis (Part B) in plant science. A number of relevant cases are presented in order to demonstrate how the analytical developments have unravelled the functional roles of elements in plants science. These cases show that ICP-MS is an essential technology in plant metallomic platforms.
TL;DR: Ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) combined with high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for the determination of mercury species in liquid cosmetic samples is described as mentioned in this paper.
Abstract: Ionic liquid based dispersive liquid–liquid microextraction (IL-DLLME) combined with high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for the determination of mercury species in liquid cosmetic samples is described. Firstly mercury (Hg2+), methylmercury (MeHg+) and ethylmercury (EtHg+) were complexed with ammonium pyrrolidinedithiocarbamate (APDC), and then the complexes were extracted into 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]) using DLLME. Under the optimized conditions, the enrichment factors of 760, 115, 235 for Hg2+, MeHg+ and EtHg+ were obtained from only 5.00 mL sample solution. The detection limits of the analytes (as Hg) were 1.3 ng L−1 for Hg2+, 7.2 ng L−1 for MeHg+ and 5.4 ng L−1 for EtHg+, respectively. The relative standard deviation (n = 10) of 0.5 ng mL−1 Hg2+, MeHg+ and EtHg+ were 7.4%, 5.2% and 2.3%, respectively. Finally, the developed method was successfully applied for the speciation of mercury in four liquid cosmetic samples, Hg2+ was found as the main species in these samples, and a spike test was performed to verify the accuracy of the method.
TL;DR: An overview of laser plasma spectrochemistry is presented in this article to demonstrate its wide range of capabilities, including elemental, isotopic, molecular, quantitative and qualitative sample analysis with sub-micron spatial resolution.
Abstract: An overview of laser plasma spectrochemistry is presented to demonstrate its wide range of capabilities. Laser plasmas offer the ability to perform elemental, isotopic, molecular, quantitative and qualitative sample analysis with sub-micron spatial resolution, and each feature can be measured at standoff distances. Obviously, these attributes are not all achievable at the same time, but they can be optimized for specific applications. This manuscript gives a sampling (pun intended) of the research in our group that has demonstrated each of these capabilities. Although the technology is commonly referred to as LIBS (laser-induced breakdown spectroscopy), the authors prefer to use laser plasma spectrometry to represent the underlying science.