Showing papers in "Journal of Analytical Atomic Spectrometry in 2013"
TL;DR: In this article, the feasibility of the single particle inductively coupled plasma mass spectrometry (SP-ICPMS) methodology applied to nanoparticle size characterization and quantification has been investigated.
Abstract: The metrological criteria for the implementation of the single particle inductively coupled plasma mass spectrometry (SP-ICPMS) methodology applied to nanoparticle size characterization and quantification have been investigated. The SP-ICPMS basis involves a process of counting events corresponding to individual nanoparticles, which requires (i) isolation of the contribution of the nanoparticles from that of the background/dissolved analyte, and (ii) avoiding the occurrence of multiple-nanoparticle events. A criterion based on three times the standard deviation of the continuous background (3σ) was selected as the threshold for discrimination of nanoparticle events from the background. Because the detectability of nanoparticles depends on both the size and number concentration, this 3σ criterion was also selected for detection of nanoparticles at the size detection limit and concentrations over the number concentration detection limit. However, at very low number concentrations, a less restrictive criterion must be used. The selection of a critical nanoparticle number concentration, based on the sample introduction and data acquisition parameters, allows the minimization of the occurrence of multiple-nanoparticle events, as well as controlling of the precision associated with the counting of nanoparticle events. Under such conditions, the standard uncertainty associated with the determination of number concentrations was 5%. The uncertainty for the determination of nanoparticle diameters was also studied, varying from 3 to 10% for diameters in the range of 100–40 nm, respectively. Reliable average number concentrations and sizes were obtained, although the number size distributions showed a significant broadening contribution due to the SP-ICPMS measurement process. The feasibility of SP-ICPMS for the implementation of the European Commission definition of 'nanomaterial' was studied by analyzing commercial silver nanoparticle suspensions.
215 citations
TL;DR: The first commercially available XRF scanner for paintings, consisting of an X-ray tube mounted with a Silicon-Drift (SD) detector on a motorized stage to be moved in front of a painting, was presented in this article.
Abstract: Scanning macro-X-ray fluorescence analysis (MA-XRF) is rapidly being established as a technique for the investigation of historical paintings. The elemental distribution images acquired by this method allow for the visualization of hidden paint layers and thus provide insight into the artist's creative process and the painting's conservation history. Due to the lack of a dedicated, commercially available instrument the application of the technique was limited to a few groups that constructed their own instruments. We present the first commercially available XRF scanner for paintings, consisting of an X-ray tube mounted with a Silicon-Drift (SD) detector on a motorized stage to be moved in front of a painting. The scanner is capable of imaging the distribution of the main constituents of surface and sub-surface paint layers in an area of 80 by 60 square centimeters with dwell times below 10 ms and a lateral resolution below 100 μm. The scanner features for a broad range of elements between Ti (Z = 22) and Mo (Z = 42) a count rate of more than 1000 counts per second (cps)/mass percent and detection limits of 100 ppm for measurements of 1 s duration. Next to a presentation of spectrometric figures of merit, the value of the technique is illustrated through a case study of a painting by Rembrandt's student Govert Flinck (1615–1660).
168 citations
TL;DR: In this article, the molybdenum (Mo) stable isotope system has been applied to a variety of geochemical and environmental problems, and a comparison of results generated in different laboratories using different analytical approaches is only possible if the in-house standards are of identical Mo isotope composition.
Abstract: The molybdenum (Mo) stable isotope system has been applied to a variety of geochemical and environmental problems. In the absence of a universally accepted zero-delta reference material, different groups report their data relative to their adopted in-house standards. Rigorous comparison of results generated in different laboratories using different analytical approaches is only possible if the in-house standards are of identical Mo isotope composition. To determine potential isotopic differences among various standards, the δ98Mo (98Mo/95Mo) values of ten Mo standard solutions were measured as part of this study. For six of these solutions, four laboratories carried out an intercalibration. In contrast to previous results, δ98Mo of various in-house standards were found to differ by up to 0.37‰. Renormalisation of our new and published Mo-isotope data available for seawater taken from various sites and the USGS rock reference material SDO-1 relative to NIST-SRM-3134, provides a much better agreement among reported δ98Mo values for these samples. Relative to NIST-SRM-3134, the δ98Mo of SDO-1 is 0.80 ± 0.14‰ (2s), while oxic, open-ocean seawater is characterised by an average δ98Mo of 2.09 ± 0.10‰ (2s). This intercalibration provides a solid platform for comparing and amending existing δ98Mo values. In addition, we recommend that future Mo isotope studies adopt NIST-SRM-3134 as a universal zero-delta reference material.
153 citations
TL;DR: A prototype inductively coupled plasma time-of-flight mass spectrometer (ICPTOFMS) for time resolved measurements of transient signals in the microsecond regime is described in this article.
Abstract: A prototype inductively coupled plasma time-of-flight mass spectrometer (ICPTOFMS) for time resolved measurements of transient signals in the microsecond regime is described in this work. Analytical figures of merit for the prototype are given for both liquid nebulization and single droplet introduction and are compared to a conventional quadrupole-based ICPMS using the same ICP source and vacuum interface. Quasi-simultaneous detection at a time resolution of 33 μs of the prototype ICPTOFMS allows multi-isotope monitoring of short signals (200–500 μs duration) generated from individual droplets and particles. The capabilities of the instrument for the analysis of single nanoparticles are studied using microdroplets consisting of a multi-element standard solution and containing 114 nm Au particles. The detection efficiencies for Ag and Au, calculated from the response of individual droplets and particles, are similar to those of the quadrupole-based instrument and amount to 1.3 × 10−6 ions per atom and 3.1 × 10−6 ions per atom, respectively. The sizes of the smallest detectable Ag, Au and U metallic nanoparticles are estimated to be 46 nm, 32 nm and 22 nm, respectively. Furthermore, time shifts of the signals of different elements within single droplets were observed. These new results demonstrate the advantage of the temporal resolution of the instrument for studying processes taking place in the plasma on the μs-time scale.
148 citations
TL;DR: Li et al. as discussed by the authors applied a non-linearized multivariate dominant factor based partial least square (PLS) model to analyze coal properties through laser-induced breakdown spectroscopy (LIBS).
Abstract: Fast or online coal property analysis would greatly improve coal pricing reliability and combustion optimization for power generation, especially in China. A non-linearized multivariate dominant factor based partial least square (PLS) model was applied to analyze coal properties through laser-induced breakdown spectroscopy (LIBS). The dominant factor explicitly modeled the direct correlation between coal property and spectral line intensities, whereas residual errors were corrected by PLS method with full spectral information. The results demonstrated an overall improvement over conventional PLS method for ash content, volatile content, and calorific value measurement. For example, the root mean square error of prediction of calorific value was decreased from 1.63 MJ kg−1 to 1.33 MJ kg−1; and the average relative error of all samples was reduced from 3.55% to 2.71%. Although current LIBS application results for coal proximate analysis have not met the national standard, LIBS is shown to be fully capable of providing useful information for coal combustion optimization and reliable references for coal pricing, showing LIBS has great potential for coal property analysis for the power generation industry.
91 citations
TL;DR: In this paper, a combination of dispersive micro solid-phase extraction (DMSPE), using multiwalled carbon nanotubes (MWCNTs) as solid sorbents, with total-reflection X-ray fluorescence spectrometry (TXRF) is proposed for preconcentration and determination of lead and cadmium ions in water samples.
Abstract: In this paper the combination of dispersive micro solid-phase extraction (DMSPE), using multiwalled carbon nanotubes (MWCNTs) as solid sorbents, with total-reflection X-ray fluorescence spectrometry (TXRF) is proposed for preconcentration and determination of lead and cadmium ions in water samples. The proposed sample preparation is quite simple and economic. After the sorption processes of the metals on the MWCNTs, the aqueous sample is separated by centrifugation and the metal loaded MWCNTs are suspended using a small volume of an internal standard solution and analyzed directly by TXRF. Parameters affecting the extraction process (complexing agent, pH of the aqueous sample, amount of MWCNTs) and TXRF analysis (volume of the deposited suspension on the reflector, drying mode, and instrumental parameters) have been carefully evaluated to test the real capability of the developed methodology for the determination of Cd and Pb at trace levels. For both elements the linear range is observed up to 50 ng mL−1. Under optimized conditions detection limits are 1.0 ng mL−1 and 2.1 ng mL−1 for Cd(II) and Pb(II) ions, respectively. Both of the examined elements can be determined with quantitative recoveries (ca. 100%) and with an adequate precision (RSD = 6.0% and 10.5% for Cd(II) and Pb(II), respectively). Our results give insight into the possibilities of the combination of DMSPE and TXRF for trace metal determination in different types of environmental waters (sea, river and waste water).
90 citations
TL;DR: In this article, an improved method for the quantification of silver nanoparticles (Ag-NPs) in environmental samples in the nanogram per litre range by means of cloud point extraction (CPE) and electrothermal atomic absorption spectrometry (ETAAS) is presented.
Abstract: The continuing boom of nanotechnology leads to the question of the environmental fate of engineered nanoparticles. In this study an improved method for the quantification of silver nanoparticles (Ag-NPs) in environmental samples in the nanogram per litre range by means of cloud point extraction (CPE) and electrothermal atomic absorption spectrometry (ETAAS) is presented. Separation of nanoparticles from ionic silver species is achieved by addition of the ligand EDTA. A limit of detection (LoD) as low as 0.7 ng L−1 was obtained by optimizing the extraction conditions, the enrichment factor, and the ETAAS measurement conditions. In comparison to previously published studies the LoD for silver nanoparticles after CPE is improved by a factor of 10 because ETAAS detection requires no additional sample digestion after extraction. Samples of different complexity such as river water, treated and untreated municipal wastewater and synthetic solutions containing dissolved and particulate organic matter with a total organic carbon (TOC) content up to 10 mg L−1 were spiked with different concentrations of Ag-NPs and a high recovery (>80%) was found in all cases. Due to the low LoD and high tolerance levels for other particulate matter, TOC and ionic species, selective determination of Ag-NPs in municipal wastewater and also in the effluent of sewage treatment plants is now possible.
88 citations
TL;DR: In this article, an accurate, sensitive and fast analytical method for the determination of S in organic matrices by means of a recently developed triple quadrupole ICP-MS instrument, operated in MS/MS mode is described.
Abstract: Accurate determination of low levels of S in organic matrices by means of isotope dilution ICP-single quadrupole MS (eg, for quantification of S components in reverse phase HPLC-ICP-MS experiments) is often not feasible This work describes an accurate, sensitive and fast analytical method for the determination of S in organic matrices by means of a recently developed ‘triple quadrupole’ ICP-MS instrument, operated in MS/MS mode The added value of the MS/MS approach for this application has been clearly visualised by varying the width of the bandpass of the first quadrupole analyzer from “fully open” (standard mode) down to single mass width (MS/MS mode) As a proof-of-concept, a biodiesel reference material has been analysed for its S content with the proposed method, using isotope dilution for calibration, and the results obtained were in excellent agreement with the certified value (within experimental uncertainty)
87 citations
TL;DR: In this article, a miniature laser ablation/ionisation reflectron-type time-of-flight mass spectrometer (LMS) using a fs-laser ablation ion source (775 nm, 190 fs, 1 kHz) was used to perform elemental and isotopic compositions of several NIST standards.
Abstract: Mass spectrometric analysis of elemental and isotopic compositions of several NIST standards is performed by a miniature laser ablation/ionisation reflectron-type time-of-flight mass spectrometer (LMS) using a fs-laser ablation ion source (775 nm, 190 fs, 1 kHz). The results of the mass spectrometric studies indicate that in a defined range of laser irradiance (fluence) and for a certain number of accumulations of single laser shot spectra, the measurements of isotope abundances can be conducted with a measurement accuracy at the per mill level and at the per cent level for isotope concentrations higher and lower than 100 ppm, respectively. Also the elemental analysis can be performed with a good accuracy. The LMS instrument combined with a fs-laser ablation ion source exhibits similar detection efficiency for both metallic and non-metallic elements. Relative sensitivity coefficients were determined and found to be close to one, which is of considerable importance for the development of standard-less instruments. Negligible thermal effects, sample damage and excellent characteristics of the fs-laser beam are thought to be the main reason for substantial improvement of the instrumental performance compared to other laser ablation mass spectrometers.
85 citations
TL;DR: In this paper, the results indicate that, upon fading, the Prussian blue pigment painted with a linseed oil binder and (PbCO3)2Pb(OH)2 or ZnO, and to a lesser extent with TiO2, undergoes a reduction at the exposed paint surface and an oxidation in the bulk of the paint layer.
Abstract: Prussian blue, a mixed valence pigment, typically KFeIII[FeII(CN)6]·xH2O, was the most widely used blue artistic pigment from ca. 1720 to the 1970's but, unfortunately, its paint layers, especially when used in conjunction with a white pigment, tend to fade or turn green upon extended exposure to light. In order to identify the mechanism underlying these changes, paint layers have been prepared with differing amounts of these white pigments and subjected to accelerated light exposure fading. The resulting unfaded and faded paint layers as well as both the Berlin white pigment, Fe2II[FeII(CN)6], and the partially oxidized Berlin green pigment, {KFeIII[FeII(CN)6]}x{FeIII[FeIII(CN)6]}1−x, have been characterized by Raman and iron-57 Mossbauer spectroscopy. The results indicate that, upon fading, the Prussian blue pigment painted with a linseed oil binder and (PbCO3)2Pb(OH)2 or ZnO, and to a lesser extent with TiO2, undergoes a reduction at the exposed paint surface and an oxidation in the bulk of the paint layer. This combined reduction and oxidation disrupts, at least in part, the FeIII–N–C–FeII intervalent electron transfer pathways in Prussian blue thus leading to pigment fading through a reduction in the intervalent electron transfer absorbance at about 700 nm.
79 citations
TL;DR: Combining Cu concentration values and Cu isotopic information allows classification of WD patients, infants and controls into different groups, while the use of concentration values only is not sufficient for this purpose.
Abstract: Wilson's disease (WD) is a genetic disorder affecting Cu metabolism, which can lead to severe physiological and neurological symptoms, and even death if untreated. Based on the fact that WD patients show low Cu levels in serum, implementation of screening programs for diagnosis of this condition at the moment of birth, when progression of the disease can be still arrested, has been attempted in the past. These attempts, however, have been unsuccessful, as healthy new-borns often show low Cu levels in serum due to liver immaturity. In this work, the potential use of isotopic analysis of Cu in serum samples as an alternative diagnostic parameter for Wilson's disease has been investigated. For this purpose, the Cu isotopic composition of a set of serum samples from different groups showing either low (i.e. WD patients, patients who had undergone bariatric surgery, infants) or normal (supposedly healthy adults) Cu concentration levels was determined by means of multi-collector ICP-mass spectrometry (MC-ICP-MS), after chromatographic isolation of Cu. For this purpose, AG-MP-1 strong anion exchange resin was relied upon, enabling quantitative recovery of Cu in pure form from the serum samples. MC-ICP-MS measuring conditions were optimized to avoid the influence of spectral overlap, and Ni was admixed as an internal standard for correction of instrumental mass discrimination. The use of this optimized method provided δ65Cu for the serum samples with a typical analytical uncertainty of ±0.20‰ (k = 2). Our results show that, for the population considered in this study, combination of Cu concentration values and Cu isotopic information allows classification of WD patients, infants and controls into different groups, while the use of concentration values only is not sufficient for this purpose. Although further studies with a larger number of samples are needed, results are encouraging as far as the use of Cu isotopic analysis for early diagnosis of Wilson's disease is concerned.
TL;DR: In this article, the use of an ultraviolet femtosecond (fs) and nanosecond(ns) double-pulse scheme was proposed to improve the analytical capabilities of LIBS in the few-micron (<2 μm) spatial resolution regime.
Abstract: We study the use of an ultraviolet (UV) femtosecond (fs)–nanosecond (ns) double-pulse scheme to improve the analytical capabilities of Laser Induced Breakdown Spectroscopy (LIBS) in the few-micron (<2 μm) spatial resolution regime. We show that a double-pulse orthogonal configuration can enhance the spectral emission intensity by roughly 360 times as compared to a single-fs laser pulse LIBS of silicon (Si). Although the spectral emission lifetime in single-pulse LIBS is less than 20 ns, the second pulse provides signal enhancement hundreds of nanoseconds later, indicating that a significant number of non-radiative species (neutrals and/or particles) exist in these small length-scale plasmas long after the fs-laser pulse is over. The double-pulse configuration is a practical way to improve the limits of detection of LIBS for micron/submicron spatial resolution.
TL;DR: In this paper, a new magnetic solid sorbent was synthesized using 3-mercaptopropionic acid grafted silica modified Fe3O4 magnetic nanoparticles, which was characterized by SEM, XRD, and FT-IR and used for solid phase extraction of Al3+ and Cr3+ ions.
Abstract: A new magnetic solid sorbent was synthesized using 3-mercaptopropionic acid grafted silica modified Fe3O4 magnetic nanoparticles. The sorbent was characterized by SEM, XRD, and FT-IR and used for solid phase extraction of Al3+ and Cr3+ ions. Al3+ and Cr3+ ions were measured by graphite furnace and flame atomic absorption spectrometry, respectively. The optimal extraction/preconcentration conditions including pH of sample solution, desorption conditions (type, concentration, and volume of the eluent), sonication time, sample volume, adsorbent amount, and interfering ions were studied. Under optimal conditions, the detection limits of 0.09 and 0.19 ng mL−1 were obtained with a relative standard deviation (RSD%) of 2.1–5.2% for Al3+ and Cr3+ ions, respectively. The enrichment factors were found to be 99 and 92 for Al3+ and Cr3+ ions, respectively. The effects of various cationic interferences on percent recovery of Al3+ and Cr3+ ions were studied. The developed method was successfully applied for selective extraction and preconcentration of trace amounts of Al3+ and Cr3+ in biological and environmental samples.
TL;DR: A micro droplet generator (μDG) is applied for sample introduction of single selenized yeast cells into a sector field ICP-MS, which was operated in a fast scanning mode with sampling rates of up to 10 kHz, to measure single cells time resolved with 100 μs integration time.
Abstract: We have applied a micro droplet generator (μDG) for sample introduction of single selenized yeast cells into a sector field ICP-MS, which was operated in a fast scanning mode with sampling rates of up to 10 kHz, to measure single cells time resolved with 100 μs integration time Selenized yeast cells have been used as a model system for preliminary investigation The single cells to be measured have been embedded into droplets and it will be shown that the time duration of a single cell event always is about 400 to 500 μs, and thus comparable to the time duration of a droplet without a cell A fixed droplet generation rate of 50 Hz produced equidistant signals in time of each droplet event and was advantageous to separate contribution from background and blank from the analytical signal Open vessel digestion and a multielement analysis were performed with washed yeast cells and absolute amounts per single cell were determined for Na (091 fg), Mg (94 fg), Fe (59 fg), Cu (054 fg), Zn (12 fg) and Se (72 fg) Signal intensities from single cells have been measured for the elements Cu, Zn and Se, and histograms were calculated for about 1000 cell events The mean elemental sensitivities measured here range from 07 counts per ag (Se) to 10 counts per ag (Zn) with RSD's from 49% (Zn) to 69% (Se) for about 1000 cell events
TL;DR: In this paper, a micro-droplet generator (μDG) sample introduction system was coupled to a sector field ICP-MS instrument to investigate the analytical figures of merit with respect to single cell analysis.
Abstract: A micro-droplet generator (μDG) sample introduction system was coupled to a sector field ICP-MS instrument to investigate the analytical figures of merit with respect to single cell analysis. The sector field instrument was operated for the first time in a fast scanning mode (E-scan) with the shortest time resolution of 100 μs to measure the single droplet time resolved and using the original detector in a pulse counting mode without modification of the existing electronics. For reduction of the droplet diameter a triple pulse mode of the droplet generator was applied and a droplet diameter down to 23 μm has been achieved for this investigation with a 100% transport efficiency of droplets. Signal duration times of single droplets of less than 500 μs have been measured. Overall detection efficiencies in the range of 10−3 counts per atom have been achieved and absolute limits of detection range between 120 ag for Fe and 1.1 ag for Mg as a mean value from 1000 droplet events.
TL;DR: In this article, a simplified chemical treatment has developed to determine high-precision δ11B in silicate rocks by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) using sample standard-bracketing (SSB) mode.
Abstract: A method with simplified chemical treatment has developed to determine high-precision δ11B in silicate rocks by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) using sample-standard-bracketing (SSB) mode. Boron in silicate rocks was extracted by digesting with HF, and purified by a single ion-exchange chromatographic step through a column filled with AG MP anion resin. Only one dryness process was involved in the entire chemical treatment procedure. This simplified procedure diminishes the risk of boron contamination and losses during chemical treatment. An introduction system with a PFA spray chamber and a sapphire injector was adopted to decrease boron memory during the measurement on MC-ICP-MS, which provides high-precision δ11B results. The internal precision for δ11B was better than ±0.05‰ (2σ standard error), and the external precision for δ11B was better than ±0.30‰ (2σ standard error) estimated by the long-term results of SRM 951. The δ11B of a series of international rock standard references were measured by this method. Some of the samples have δ11B reference values, and our results agree well with them within analytical errors. This indicates that our method is feasible for high-precision δ11B measurement in various silicate rocks, and our results may provide δ11B reference values for these rock standards.
TL;DR: In this paper, an intense discharge spark was observed with a peak discharge current of 163 kA and a peak power of 81 MW, and only lasted for ∼51 ns, and the precision in terms of the relative standard deviation (RSD) of time delay between the laser firing and discharge was 17% with a discharge voltage of 9 kV, while the RSD of line intensities from repeatable measurements was typically about 2-3%.
Abstract: Nanosecond discharge enhanced laser-induced breakdown spectroscopy of silicon was investigated An intense discharge spark was observed with a peak discharge current of 163 kA and a peak power of 81 MW, and only lasted for ∼51 ns The discharge stability and the effect of the capacitances on the discharge and optical emission were investigated A stable discharge process and optical emission were observed The precision in terms of the relative standard deviation (RSD) of time delay between the laser firing and discharge was 17% with a discharge voltage of 9 kV, while the RSD of line intensities from repeatable measurements was typically about 2–3% The measured line intensities of atomic and ionic states of silicon were used for electron temperature calculation by employing Saha–Boltzmann plots Electron number density was determined by using the Stark broadening of two silicon atomic lines Compared to the laser induced plasma, the temperature of the discharge enhanced plasma was increased, while the electron number density in the discharge plasma was roughly the same in the laser ablation nanosecond discharge enhanced Si plasma
TL;DR: In this paper, simple procedures for the determination of Cr, Ni, Pb and V in gasoline and ethanol fuel by microwave plasma optical emission spectrometry (MIP OES) are described.
Abstract: Simple procedures for the determination of Cr, Ni, Pb and V in gasoline and ethanol fuel by microwave plasma optical emission spectrometry (MIP OES) are described. Ethanol fuel samples were simply diluted in an aqueous 1% v/v HNO3 solution. For gasoline, microemulsions in n-propanol were prepared. The MIP OES instrument requires no separate gas source since a N2 gas generator coupled to a simple air compressor is sufficient to maintain the microwave-induced plasma. An external gas control module (EGCM) is used to inject air into the plasma in order to minimize background emissions and avoid carbon deposition on the torch and on the pre-optical window. The Flow Blurring Nebulizer (FBN) technology was also employed to ensure more efficient and homogeneous sample aerosols, which contributes to plasma stability and lower limits of detection (LODs). Nebulizer gas pressure and plasma viewing position were optimized separately for each analyte. Gasoline and ethanol fuel samples were analyzed and the calculated LODs were in the range of 0.3–60 μg L−1 or 4–1700 μg kg−1 for all analytes. The accuracy was checked by spike experiments and recoveries between 84 and 123% were obtained.
TL;DR: In this article, various elemental mapping collection strategies are described, including quantitative mapping at the major (concentration C > 0.1 mass fraction), minor (0.01 ≤ C ≤ 0. 1), and trace (C < 0.01) constituent levels, extreme pixel density (gigapixel) mapping, rapid mapping, and high spatial resolution mapping with the thermal field emission gun scanning electron microscope.
Abstract: Elemental mapping at the microstructural level by scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS), while widely applied in science, engineering, and technology, has been limited in performance by the throughput of the lithium-drifted silicon detector [Si(Li)-EDS] which restricts the number of X-ray counts measured per image pixel. The emergence of the silicon drift detector (SDD-EDS) has greatly extended the X-ray throughput, by a factor of 25 to 70 for the same spectral resolution. This improved performance enables practical X-ray spectrum imaging (XSI), in which a complete X-ray spectrum is recorded at each image pixel. By performing complete quantitative corrections for background, peak overlap, and matrix effects to each pixel spectrum, full compositional mapping can be achieved. Various elemental mapping collection strategies are described, including quantitative mapping at the major (concentration C > 0.1 mass fraction), minor (0.01 ≤ C ≤ 0.1), and trace (C < 0.01) constituent levels, extreme pixel density (gigapixel) mapping, rapid mapping (in 10 seconds or less), and high spatial resolution mapping with the thermal field emission gun scanning electron microscope.
TL;DR: In this paper, a Triple Quadrupole ICP-MS was used for the determination of 129I in soil samples with the objective of investigating radioiodine released by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident.
Abstract: A method was developed for the determination of 129I in soil samples using a Triple Quadrupole ICP-MS, with the objective of investigating radioiodine released by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. The determination of 129I by ICP-MS is capable of providing a high sample throughput compared to other methods. Nonetheless, the high background caused by 129Xe impurities in argon plasma gas and polyatomic ions such as 127IH2+ and 127ID+ has made it difficult to carry out determinations of this isotope by conventional ICP-MS instruments. In this study, oxygen was used as a reaction gas for reducing the background intensity of m/z 129, principally by 129Xe. The contribution of polyatomic ions such as 127IH2+ and 127ID+ could be effectively corrected for by assuming a production ratio of 5 × 10−9. The detection limit for 129I in solution was successfully improved. The measured 129I/127I ratios in NIST SRM 3231 Level II standard solution are consistent with the certified value of 0.981 × 10−8 within the analytical error, suggesting the reliability of the method to the measurement of 129I/127I. In order to confirm the applicability of this method to the measurement of 129I/127I ratios of Fukushima soils, samples were collected for analysis from 5–60 km away from the FDNPP. Prior to the ICP-MS measurement iodine fractions were separated from soil by pyrohydrolysis and were purified by solvent extraction. The 129I/127I ratios in the samples are consistent with values determined by accelerator mass spectrometry (AMS) within the analytical error. This method provides a powerful tool for the investigation of radioiodine contamination in Fukushima and elsewhere.
TL;DR: In this article, a solution-cathode glow discharge is coupled to a compact spectrograph, which results in a small, potentially portable instrument that can simultaneously detect a range of metals by optical emission spectrometry.
Abstract: A solution–cathode glow discharge is coupled to a compact spectrograph. Such a coupling results in a small, potentially portable instrument that can simultaneously detect a range of metals by optical emission spectrometry. Detection limits were calculated for Ag (1 ppb), Cd (2 ppb), Cu (8 ppb), Fe (40 ppb), Hg (20 ppb), Mg (3 ppb), Ni (12 ppb), Pb (10 ppb) and Se (3 ppm). These values are similar to those for an earlier, monochromator-based solution–cathode glow discharge system. All calibration curves showed good linearity (R2 ≥ 0.9994). Short-term precision ranged from 0.6–7%.
TL;DR: The distribution of trace-metals and organic sulphur in Archaeopteryx strongly suggests that remnants of endogenous eumelanin pigment have been preserved in the feathers of this iconic fossil.
Abstract: Charles Darwin acknowledged the importance of colour in the natural selection of bird plumage. Colour can indicate age, sex, and diet, as well as play roles in camouflage, mating and establishing territories. Feather and integument colour depend on both chemical and structural characteristics and so melanosome structure and trace metal biomarkers can be used to infer colour and pigment patterns in a range of extant and fossil organisms. In this study, three key specimens of Archaeopteryx were subjected to non-destructive chemical analysis in order to investigate the potential preservation of original pigmentation in early fossil feathers. Synchrotron Rapid Scanning X-ray Fluorescence (SRS-XRF) maps are combined with sulphur X-ray Absorption Near Edge Structure (XANES) spectroscopy to provide the first map of organic sulphur distribution within whole fossils, and demonstrate that organically derived endogenous compounds are present. The distribution of trace-metals and organic sulphur in Archaeopteryx strongly suggests that remnants of endogenous eumelanin pigment have been preserved in the feathers of this iconic fossil. These distributions are used here to predict the complete feather pigment pattern and show that the distal tips and outer vanes of feathers were more heavily pigmented than inner vanes, contrary to recent studies. This pigment adaptation might have impacted upon the structural and mechanical properties of early feathers, steering plumage evolution in Archaeopteryx and other feathered theropod dinosaurs.
TL;DR: In this article, a pressure-induced dispersion of 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] into the aqueous sample was used to decrease the dissolution and increase hydrophobicity of the ionic liquid to entrap vanadium in a labile hydrophobic chelate with 8-hydroxyqunioline (8-HQ).
Abstract: A simple and new liquid–liquid dispersive microextraction termed pressure-assisted ionic liquid dispersive microextraction (PILDME) was developed for the concentration of trace levels of vanadium in real water samples followed by its quantification by graphite furnace atomic absorption spectrometry (GFAAS). We performed a pressure-induced dispersion of 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] into the aqueous sample. Chloroform was used to decrease the dissolution and increase hydrophobicity of the ionic liquid to entrap vanadium in a labile hydrophobic chelate with 8-hydroxyqunioline (8-HQ). Several variables playing a vital role in the prescribed procedure were studied and optimized. With optimum experimental values of significant variables, the detection limit (LOD) and the enhancement factor (EF) were observed to be 20 ng L−1 and 100, respectively. The precision of the method was checked by detection of the relative standard deviation (RSD) as 4.5% at a vanadium concentration of 0.5 μg L−1. The validity and accuracy of the applied method were tested by vanadium extraction and quantification of the standard reference material “SLRS-4 Riverine water”, and the results were found to be in good agreement with the certified values. The method was satisfactorily applied to real water samples.
TL;DR: In this article, Roman black gloss ceramics from two different locations and separated by 50-80 years were investigated by X-ray absorption near edge structure analysis in full field hard Xray transmission microscopes.
Abstract: Roman black gloss ceramics from two different locations and separated by 50–80 years were investigated by X-ray absorption near edge structure analysis in full field hard X-ray transmission microscopes. These spectro-microscopy measurements were complemented by Raman spectroscopy, and X-ray diffraction spot analyses to gain insights into possible differences in manufacturing technology. Our results indicate that the two vessels underwent significantly different firing protocols, suggesting that there was a surprisingly quick evolution of a complex technological process in response to changing needs and tastes of a burgeoning empire. Furthermore, our results show that the ability of the full field X-ray spectro-microscope to investigate large sample areas (from hundreds of µm2 to as much as 2 mm2) with high spatial resolution (of 300 nm down to 30 nm) together with its ability to correlate sample porosity (derived from tomography) with the distribution of chemical phases makes it an invaluable tool in the investigation of nanoscale processes in hierarchically heterogeneous chemical systems—from Roman ceramics to some of the most advanced technological products of today.
TL;DR: In this paper, the authors investigated the corrosion products of a 450 year old archaeological iron nail at the nanometer level using STXM and showed the presence of an interfacial layer of about 100 nm at the metal-corrosion product interface consisting of maghemite and magnetite.
Abstract: For the first time, corrosion products of a 450 year old archaeological iron nail were investigated at the nanometer level using STXM. NEXAFS acquisitions at the Fe L-edge were performed on a thin film taken of the metal–corrosion products including the interface. Comparison with Fe L-edge reference spectra gathered on maghemite (Fe2O3), magnetite (Fe3O4), siderite (FeCO3), chukanovite (Fe2(OH)2CO3) and metallic iron (Fe) showed the presence of an interfacial layer of about 100 nm at the metal–corrosion product interface consisting of maghemite and magnetite. Further from this interface, corrosion products are mainly constituted of Fe-carbonates, as well as smaller quantities of iron oxides, probably maghemite. These results support the hypothesis of the presence of a nanolayer controlling the corrosion processes at the metal–corrosion product interface, proposed during former studies at the macroscopic and microscopic levels. They also bring important new insights for the prediction of very long term corrosion of steels, especially into the fields of cultural heritage conservation and storage of nuclear wastes.
TL;DR: Trace impurities of sodium, lithium, magnesium, and potassium in colloidal silica were determined by slurry introduction into an atmospheric-pressure solution-cathode glow discharge (SCGD).
Abstract: Trace impurities of sodium, lithium, magnesium, and potassium in colloidal silica were determined by slurry introduction into an atmospheric-pressure solution-cathode glow discharge (SCGD). The applied voltage, solution flow rate, and distance between the metal anode and surface of the solution were optimized. Emission from K (766.5 nm), Na (589.0 nm), Mg (285.2 nm) and Li (670.8 nm) demonstrated a linear range of nearly 4 orders of magnitude (R2 ≥ 0.998) and steady-state sample introduction yielded limits of detection of 0.7, 0.4, 0.5 and 0.2 ng mL−1, respectively. For an integration time of 0.3 s, relative standard deviations (RSDs) from 1000 ng mL−1 standard solutions introduced continuously were found to be better than 3% for all four elements. Transient sample introduction into the SCGD was also optimized and provided limits of detection for K, Na, Mg and Li of 3, 2, 2 and 0.8 ng mL−1, respectively, and RSDs for 1000 ng mL−1 standard solutions of better than 3%. Determined concentrations of trace impurities in colloidal silica agreed satisfactorily (accuracy from 1.3 to 7.7% and precision from 4 to 14%) with those obtained from inductively coupled plasma atomic emission spectrometry.
TL;DR: In this article, a modified beam guidance in the primary ion gun is proposed to reduce detector dead time effects and ion interactions to a minimum and secondary ion intensities can be obtained more accurately.
Abstract: Oxygen isotope exchange with subsequent time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a highly valuable tool for determining oxygen diffusion coefficients in oxides. Since ToF-SIMS analysis enables an elemental and chemical mapping, it can also be used to visualize oxygen exchange-active zones by determining the local oxygen isotopic fraction. However, measuring accurate isotopic fractions can be a challenging analytical task owing to secondary ion interaction and signal saturation, particularly when dealing with high secondary ion intensities as commonly found when analyzing oxygen ions from oxides. It is shown that in many cases the calculated 18O− fraction erroneously shifts to higher values and can lead to systematic errors in the determination of diffusion coefficients. A novel ToF-SIMS operation mode, called “Collimated Burst Alignment” (CBA) mode, is therefore introduced to enable a more accurate determination of oxygen isotopic fractions with an optimized lateral resolution of sub-100 nm. Both improvements are rendered possible by a modified beam guidance in the primary ion gun. This modification reduces detector dead time effects and ion interactions to a minimum and secondary ion intensities can be obtained more accurately. The result of this optimization is demonstrated in measurements of the natural isotope abundance of several different oxides including SrTiO3 and Sr-doped LaCoO3.
TL;DR: In this article, a review is devoted to the coupling of dispersive liquid-liquid microextraction with atomic spectroscopy, where the basic principles of the DLLME technique are briefly explained and experimental factors affecting the extraction efficiency, such as type and volume of the extraction and dispersive solvent, ionic strength, extraction time, centrifugation time and rate, as well as applications of surfactants and chelating reagents are discussed.
Abstract: As a new sample pre-treatment technique, dispersive liquid–liquid microextraction (DLLME) is attracting the attention of a growing number of researchers. This review is devoted to the coupling of DLLME with atomic spectroscopy. The basic principles of the DLLME technique are briefly explained. Experimental factors affecting the extraction efficiency, such as type and volume of the extraction and dispersive solvent, ionic strength, extraction time, centrifugation time and rate, as well as applications of surfactants and chelating reagents, are discussed. Recent developments in the automation of DLLME are also presented. The applications of dispersive liquid–liquid microextraction coupled with atomic spectrometry are given in a Table.
TL;DR: In this article, a plasma mass spectrometer based multiple isotope dilution method for high precision rare earth concentration analysis in aqueous media is presented, where flexible spiking of ten rare earth elements (REEs) via two LREE and HREE mixed spike solutions is used.
Abstract: The rare earth elements (REEs) are valuable tracers in the earth, ocean and environmental sciences. Ten out of fourteen stable REEs have two or more isotopes, making them suitable for quantification by isotope dilution. We present a plasma mass spectrometry based multiple isotope dilution method for high precision REE concentration analysis in aqueous media. Key aspects of the method are: (i) flexible spiking of ten REEs via two LREE and HREE mixed spike solutions. (ii) Offline pre-concentration and matrix removal, by ion chromatography for freshwater samples and by iron co-precipitation or ion chromatography with the Nobias™ resin for seawater samples. (iii) High sensitivity detection by sector field-inductively coupled plasma mass spectrometry (SF-ICP-MS). (vi) The use of a desolvation micro-nebulization introduction system to lower polyatomic Ba and LREE-oxide interferences on HREEs. The method is suitable for a range of freshwater to seawater type samples, and was validated against SLRS-4, SLRS-5, and CASS-5 reference materials and two GEOTRACES marine inter-comparison samples. Long-term external precision on all REEs was <2% RSD, except La and Ce. Minimum sample volumes are 1 ml for freshwater and 50 ml for seawater. The multispike SF-ICP-MS method should be of particular interest in exploring subtle variations in aqueous REE fractionation patterns and anomalies in large numbers of samples.
TL;DR: In this paper, the authors investigated the use of current amplifiers equipped with 1012 ohm feedback resistors in thermal ionisation mass spectrometry (TIMS) analyses of sub-nanogram sample aliquots for Nd and Sr isotope ratios.
Abstract: We have investigated the use of current amplifiers equipped with 1012 ohm feedback resistors in thermal ionisation mass spectrometry (TIMS) analyses of sub-nanogram sample aliquots for Nd and Sr isotope ratios. The results of analyses using the 1012 ohm resistors were compared to those obtained with the conventional 1011 ohm amplifiers. We adopted a method where long baselines were measured before and after data acquisition to save time during sample analysis. The noise level on the new design 1012 ohm resistors is 3–5 fold lower compared to the 1011 ohm resistors, which results in a two fold better analytical precision on 143Nd/144Nd and 87Sr/86Sr analyses for beam intensities of 10 mV for the 143Nd and 87Sr masses, respectively. Reproducibility of 87Sr/86Sr on repeat analyses of 1 ng Sr sample loads is better using 1012 ohm resistors compared to 1011 ohm resistors and is a factor of 2 better compared to previous studies. The external reproducibility of 143Nd/144Nd for 1 ng Nd sample loads is a factor of 1.4 better compared to previously published Nd+ results and is similar to those obtained using the more time-consuming NdO+ techniques. Reproducibility tests on 100 pg Nd and Sr samples of reference materials yield 176 ppm of 143Nd/144Nd and 92 ppm of 87Sr/86Sr. These data suggest that we can resolve variability in the fourth decimal place of Nd and Sr isotope ratios in geological samples as small as 100 pg.