SCIENTIFIC PUBLICATIONS USING ELEMENTAL SCIENTIFIC PRODUCTS

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Measuring the isotopic composition of trace elements in zircon: application to radiogenic molybdenum

ID: 1830
Year: 2018
Products: Elemental Scientific Apex-Q desolvating nebulizer
Authors: Mayer, AJ;Wieser, M;Matthews, W;Thompson, RI;
Journal: arXiv preprint arXiv

Techniques have been developed to measure the isotopic composition of trace elements from matrices predominantly consisting of interfering isotopes. These techniques have been applied to measuring mass-independent fractionation of molybdenum in ancient zircon samples due to nuclear decays. Improvements to the digestion of large zircon samples and the ion exchange chemistry required to separate trace molybdenum from zirconium silicate are presented. The efficacy of TEVA ion exchange resin as a replacement for anion resin to improve separation efficiency and chemistry blank was studied. An algorithm was established to improve background, interference and mass bias corrections for the data analysis of Mo by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). This enabled the isotopic composition measurement of 9 orders of magnitude while retaining 63% of the Mo. With 5 ng of Zr still remaining, novel data analysis techniques enabled < 0.1 permil precision on each Mo isotope. The relevance of this technique to extracting other atomic species is also discussed.

Characterization of nanoparticles in food using ICP-MC-how far have we come in the last 10 years?

ID: 1829
Year: 2018
Products: prepFAST MC
Authors: Loschner, K;
Journal: Conference

Nanotechnology and more particularly nanotechnology-based products and materials have a large potential for providing novel solutions to many of the current challenges facing society such as energy supply and resources efficiency, a clean environment, information and communication, mobility and security, and the efficiency of health-related products. Current applications in the agri/feed/food sector are food additives and food contact materials, whereas potential future developments are expected in the field of nanoencapsulates and nanocomposites in applications such as novel foods, food/feed additives, biocides, pesticides and food contact materials. With the increasing use of nanotechnology, there is a need for reliable detection and characterization methods for nanoparticles (NPs) in food and biological matrices. For regulatory purposes (e.g. Novel food, “Food labelling”), the European Commission developed a recommendation for the definition of a nanomaterial, which poses additional analytical challenges such as the need for determining a number-based particle size distribution.

Towards a future screening method for nanoparticles in seafood-for surveilance and risk assessment of food safety

ID: 1828
Year: 2018
Products: prepFAST MC
Authors: Valdersnes, S;Loschner, K;Solli, B;Kogel, T;
Journal: Conference Poster

Nanoparticles are produced or engineered, intentionally, due to their product improving properties. However, nanoparticles are also produced unintentionally, for example in mining and abrasion processes. Nanoparticles have a large surface area to volume ratio, which implies a different behavior of the compounds compared to larger particles or single ions/molecules of the same compound. Therefore, the compounds are more reactive per weight unit than larger structures of the same compounds and have different toxicities and risks compared to single ions or molecules of the same element. Negative effects of manufactured NPs on organisms, including invertebrates, fish and mammals, have been demonstrated, and the release of NPs in the marine environment may therefore cause negative effects in marine organisms. The new analytical dimension of size thus needs to be added to the already established total and species specific determination of metals and elements to aid in the future risk assessments of food safety.

Etude de la bio-calcification des coccolithophoridés dans un contexte d'acidification des océans. Calibrations de proxies (B/Ca et δ 11 B) du pH dans les coccolithes

ID: 1827
Year: 2017
Products: Autosampler SC-2 Fast ESI (Elemental scientific) ASX-100 CETAC
Authors: Delebecque, N;
Journal: Thesis

Environ 30% du dioxyde de carbone produit par des activités humaines est absorbé par l’océan menant à une diminution de pH d’eau de mer et de l’état de saturation de carbonate de calcium (CaCO3). L’acidification des océans engendrera probablement de profonds changements dans les écosystèmes marins, en particulier chez les organismes marins calcifiants. Les coccolithophoridés produisent avec les foraminifères plus de 90% des carbonates pélagiques dans l’océan actuel. Les expériences de culture ont montré que la réponse des coccolithophoridés à l’acidification des océans varie au sein d’une même espèce ce qui complique l’estimation de l’impact global sur le cycle de carbone et des rétroactions sur le climat. En effet, la sensibilité des organismes et les réponses vis-à-vis de l’augmentation du CO2 dissous dans l’océan et donc de la diminution du pH de l’eau de mer sont différentes. Les conséquences de la calcification sur les coccolithophoridés sont encore très peu décrites et quantifiées. Les coccolithes sont formés à l’intérieur de la cellule dans une vésicule interne. Le pH à l’intérieur de cette vésicule est un paramètre central qui détermine la précipitation de la calcite et donc de la formation des coccolithes. Actuellement, le pH de la vésicule ne peut pas être précisément mesuré et c’est la mesure indirecte de paramètres géochimies qui nous permet d’estimer ces processus. La capacité de réguler le pH de la vésicule vis-à-vis des changements du pH d’eau de mer permet la précipitation de calcite et détermine l’adaptation potentielle de certainscoccolithophoridés à l’acidification des océans. Deux souches d’E. huxleyi ont été cultivées dans des cultures en batchs dilués dans trois conditions pH différentes afin d’évaluer les modalités de réponse aux variations du pH de l’eau de mer. Des paramètres physiologiques incluant le taux de croissance, le POC et le PIC et ont été examinés, en parallèle aux mesures de B/Ca et δ11B dans la calcite des coccolithes pour progresser sur la compréhension de ces mécanismes intracellulaire et sur l’existence d’une relation entre ces paramètres et le pH pour évaluer le potentiel de l’isotopie du bore comme proxy du paleo-pH.

Análise de especiação e fracionamento de biocidas de zinco (Piritionato de zinco, Zineb e Ziram) utilizando SPE, DGT, HPLC e ICP-MS em água estuarina

ID: 1826
Year: 2018
Products: APEX
Authors: Rolisola, AMCM;
Journal: Thesis

 About 18 compounds are used as booster biocides (metal) in antifouling paints such as Zinc Pyrithione (Zn(PT)2), Zineb and Ziram. It is important to develop an analytical method for determining of the environmental concentrations of zinc biocides. The present study had as objectives i) to develop a solid phase extraction (SPE) and high performance liquid chromatography (HPLC) coupled to the inductively coupled plasma mass spectrometer (ICP-MS) for the determination of Zn(PT)2, Zineb and Ziram and ii) quantify in lab the total labile fraction of Zn(PT)2, Zineb and Ziram and in situ the total labile fraction of zinc using the diffusive gradient in thin films (DGT) technique in standard solution and estuarine water, respectively. In the SPE technique, the silica sorbent functionalized with phenyl presented excellent retention for Zn(PT)2, Zineb and Ziram (94 ± 0.1%, 85 ± 0.04% and 93 ± 0.1%, respectively) and recoveries between 85% and 110%. In the determination of zinc using the HPLC-VGroove-ICP-MS coupling with post-column chromatographic dilution, the mobile phase composed of methanol and 0.006 mol L-1 of ammonium acetate (50:50, v v-1) of presented the best performance in the separation of Zn(PT)2, Zineb and Ziram. The analytical curve obtained for Zn(PT)2 presented satisfactory correlation coefficient, LD and LQ for the isotopes 64Zn (0.98, 0.575 mg L -1, 1.916 mg L-1), 66Zn (0.99, 0.480 mg L-1, 1.600 mg L-1), 68Zn (0.98, 0.602 mg L-1, 2.007 mg L-1). In the DGT technique, the Chelex® 100 resin binder was used to evaluate the lability of the zinc biocides Zn(PT)2, Zineb and Ziram in estuarine water. The results showed that the total labile fraction of Zn was around 100% for Zineb (111%) and Ziram (109%), that is, these biocides formed totally labile species in the estuarine water sample and for Zn(PT)2 was 75% indicating partially labile species. The results obtained in the SPE technique in the HPLC-VGroove-ICP-MS coupling and DGT demonstrated that the methods present satisfactory performance for the determination of Zn(PT)2, Zineb and Ziram.

Benzotriazoles, benzothiazoles and inorganic elements as markers of road pollution sources in a sub-arctic urban setting [Trondheim, Norway]

ID: 1825
Year: 2018
Products: PrepFAST flow injection analysis system
Authors: Asheim, J;
Journal: Thesis

In this study, a liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of six benzothiazoles (BTHs) and seven benzotriazoles (BTRs) primarily in road dust. The target benzothiazoles were benzothiazole, 2-hydroxy-benzothiazole, 2-mercaptobenzothiazole, 2-methylthio-benzothiazole, 2-amino-benzothiazole, and 2-Morpholin-4-yl-benzothiazole, and the target benzotriazoles were benzotriazole, 1-hydroxy-benzotriazole, 4-methyl-1H-benzotriazole (tolyltriazole), 5,6-dimethyl-1H-benzotriazole (xylyltriazole), benzotriazole-5-carboxylic acid, 5-chloro-1H-benzotriazole and 5-amino-1H-benzotriazole. Benzothiazoles and benzotriazoles are known pollutants in an urban environment.Benzothiazoles are previously proposed as potential chemical markers of tire wear, while benzotriazoles are well established anticorrosive chemicals linked to metal pollution. In addition, 66 elements were measured in the road dust samples by ICP-MS analysis in order to account for inorganic pollution sources.

CHANGES TO THE ELECTROLYTE IN AGED LI-ION CELLS

ID: 1824
Year: 2018
Products: ESI SC-4DXS autosampler
Authors: Thompson, L;
Journal: Thesis

Electrolyte composition is crucial to the lifetime, cycling capability and safety of Li-ion cells. Many studies have measured electrolyte changes after formation or during the first few charge and discharge cycles, while very few consider long-term changes that occur to Li-ion electrolytes. This work highlights some previous research and describes rigorous electrolyte analysis methods. The development of the electrolyte extraction method, which allows for the reconstruction of electrolyte composition, is discussed and applied to cells which have been cycled for many months. The developed centrifuge and GC-MS/ICP-MS methods are presented in this work along with results from cells cycled to various upper cutoff potentials and from cells containing a low-viscosity co-solvent. Results from µ-XRF transition metal analysis of the negative electrode are also presented. The findings indicate some salt loss from electrolyte in cells cycled to the higher upper cutoff potentials and minimal Mn deposition found on the negative electrode. Potential reaction mechanisms to describe the observed changes are discussed and compared to previous studies. Now that the methods for rigorous analysis of the electrolyte have been established, many additional projects have been proposed as future work.

Lead, Copper, and Iron in University Tap Water

ID: 1823
Year: 2018
Products: low-flow (100 µL/min) self-aspirating nebulizer
Authors: McLendon, A;
Journal: Thesis

This study observed concentrations of lead, copper, and iron in university tap water over an eight-week span during and between the summer and fall semesters. First draw and 30s flush samples were taken after overnight stagnation from the Honor House, College Hall, J. B. George Building, and International Center bathrooms and analyzed with an inductively-coupled plasma mass spectrometer (ICPMS). There was no obvious correlation between time in the semester and metal concentrations. Relative iron levels rose and fell at the same time in all buildings, but there was little correlation between buildings for lead and copper concentrations. The Honor House had the highest first draw lead levels, and College Hall had the highest copper levels in both first draw and 30s flush samples. All of the 30s flush samples had lower metal concentrations than the first draw samples. Lead and copper concentration variations between buildings indicates influence from building infrastructure, while the correlations in iron concentrations between buildings indicates a probable system-wide factor.

Ocean acidification can interact with ontogeny to determine the trace element composition of bivalve shell

ID: 1822
Year: 2018
Products: New Wave deep ultra violet (193 nm) laser ablation system
Authors: Norrie, C;Dunphy, B;Ragg, N;Lundquist, C;
Journal: Limnol. Oceanogr.

We sought to determine how pCO2 will affect the incorporation of trace elements into bivalve shell. This was to validate that under high pCO2 conditions reconstruction of animal movements is still viable; and to investigate potential trace element proxies for ocean carbonate chemistry. Here, we examined shell of the bivalve Perna canaliculus formed under current CO2 (pCO2 = 400 μatm) conditions and those predicted to exist in 2100 (pCO2 = 1050 μatm). Seventeen trace element:calcium ratios were examined at two locations within shells. Elements that are typically most useful in determining connectivity patterns (e.g., Sr, Mn, Ba, Mg, B) were not affected by pCO2 in shell produced early in individual's lives. This suggests that the effects of ocean acidification on dispersal signatures may be dampened. However, cobalt, nickel, and titanium levels were influenced by pCO2 consistently across shells suggesting their role as potential indicators of CO2 level.

Two-Photon Fluorescence and Magnetic Resonance Specific Imaging of Aβ Amyloid Using Hybrid Nano-GdF3 Contrast Media

ID: 1821
Year: 2018
Products: SC-FAST option and SYRIX syringpump
Authors: Mpambani, F;Åslund, A;Lerouge, F;Nyström, S;Reitan, N;Huuse, E;Widerøe, M;Chaput, F;Monnereau, C;Andraud, C;Lecouvey, M;Handrick, S;Prokop, S;Heppner, F;Nilsson, P;Hammarström, P;Lindgren, M;Parola, S;
Journal: ACS Appl. Bio Mater.

Real time in vivo detection of Amyloid β (Aβ) deposits at an early stage may lead to faster and more conclusive diagnosis of Alzheimer’s disease (AD) and can facilitate the follow up of the effect of therapeutic interventions. In this work, the capability of new hybrid nanomaterials to target and detect Aβ aggregates using magnetic resonance (MRI) and fluorescence imaging is demonstrated. These smart contrast agents contain paramagnetic nanoparticles surrounded by luminescent conjugated oligothiophenes (LCOs) known to selectively bind to Aβ aggregates, with emission spectra strongly dependent on their conformations, opening the possibilities for several fluorescence imaging modes for AD diagnostics. Relaxivity is evaluated in vitro and ex vivo. The capability of these contrast media to link to Aβ fibrils in stained sections is revealed using transmission electron microscopy and fluorescence microscopy. Preliminary in vivo experiments show the ability of the contrast agent to diffuse through the blood–brain barrier of model animals and specifically stain amyloid deposits.

120,000 year record of sea ice in the North Atlantic

ID: 1820
Year: 2018
Products: syringe-pumped autosampler (Seafast II)
Authors: Maffezzoli, N;Vallelonga, P;Edwards, R;Saiz-Lopez, A;Turetta, C;Kjær, H;Barbante, C;Vinther, B;Spolaor, A;
Journal: Clim. Past Discuss.

Although it has been demonstrated that the speed and magnitude of recent Arctic sea ice decline is unprecedented for the past 1,450 years, few records are available to provide a paleoclimate context for Arctic sea ice extent. Here we present a 120 kyr record of bromine enrichment from the RECAP ice core, coastal East Greenland, and reconstruct past sea ice conditions in the North Atlantic as far north as the entrance of the Arctic Ocean (50-85 °N). Bromine enrichment has been previously 5 employed to reconstruct first-year sea ice (FYSI) in the Canadian Arctic over the last glacial cycle. We find that during the last deglaciation, the transition from multi-year sea ice (MYSI) to FYSI started at ∼17.6 kyr, synchronous with sea ice reductions observed in the eastern Nordic seas (Müller and Stein, 2014; Hoff et al., 2016) and with the increase of North Atlantic ocean temperature (Dokken and Jansen, 1999). FYSI reached its maximum extent at 12.4-11.8 kyr, after which open-water conditions started to dominate, as supported by sea ice records from the eastern Nordic seas and the North Icelandic shelf. Our results show 10 that over the last 120,000 years, sea ice extent was greatest during Marine Isotope Stage (MIS) 2 and MIS4, with decreased levels during MIS3 and the onset of the last glacial period (late-MIS5). Sea ice extent during the last 10 kyr (Holocene/MIS1) has been less than at any time in the last 120 kyr.

Simultaneous Determination of Chromium Species in Water and Plant Samples at Trace Levels by Ion Chromatography–Inductively Coupled Plasma-Mass Spectrometry

ID: 1819
Year: 2018
Products: Peltier cooled spray chamber and nebulizer
Authors: Sel, S;Erulaş, F;Turak, F;Bakırdere, S;
Journal: Analytical Letters

Ion chromatography–inductively coupled plasma-mass spectrometry (IC–ICP-MS) was used for the identification and quantification of chromium species. Chromium(III) and chromium(VI) were separated and determined by IC–ICP-MS. The separation was achieved using an anion exchange column with 0.55 M HNO3 as mobile phase. It was a particular goal of this work to exclusively use nitric acid for elution in order to reduce interferences in the ICP-MS system. Analytical figures of merit were calculated under the optimum conditions by developing calibration plots in a concentration range of 0.50–250 µg/L for both species. The detection limits for Cr(III) and Cr(VI) were 0.09 and 0.03 µg/L, respectively. Spiked recovery tests were used to evaluate the applicability of the analytical method in environmental samples, and the recoveries ranged between 97 and 103% for both analytes. The accuracy of the method for total chromium content was validated through the analysis of a spring water-certified reference material (UME 1201), and the obtained results were in good agreement with the certified value. Lettuce seedlings were cultivated to evaluate the intake levels of these species. In addition, the bioaccessibility of Cr(III) and Cr(VI) from the lettuce seedlings in simulated gastric and intestinal fluids media was examined.

Development of rapid methodologies for uranium age dating

ID: 1818
Year: 2018
Products: automated separation system
Authors: Higginson, M;Gilligan, C;Taylor, F;Knight, D;Kaye, P;Shaw, T;Thompson, P;
Journal: J Radioanal Nucl Chem

The measured model age is an important signature to constrain the production history of an unknown nuclear material. The aim of this work was to validate a rapid, robust quantification scheme for bulk uranium materials, amenable to multiple detection platforms. This work describes a combination of stacked columns, vacuum assisted separations, automation and a suite of analysis techniques to determine the ages of uranium materials and CRMs of known production history. The methodology allows for the determination of 234U/230Th and 235U/231Pa atom ratios via a novel approach, starting with a three resin column separation to allow high throughput and rapid turnaround. The materials analysed have concordant ages with known production histories, leading to the potential for expanding this work to additional chronometers, and the approach offers nuclear forensic practitioners an additional, advantageous separation methodology in the analysis of bulk uranium materials.

An alternative separation procedure for 90Sr age dating using DGA Resin

ID: 1817
Year: 2018
Products: low flow self-aspirating nebulizer
Authors: McLain, D;Tsai, Y;Graczyk, D;Canaday, J;Steeb, J;
Journal: J Radioanal Nucl Chem

The likelihood of an attack by a terrorist organization using a radiological dispersal device (RDD) is much higher than that of an attack with an improvised nuclear device or true nuclear weapon, as much less technical expertise is required to build an RDD. Consequently, there has been an effort to develop methods for age-dating radiological sealed sources in recent years. One such procedure, described by Steeb et al., is used for determining the age of 90Sr sources. That procedure utilized a rather expensive extraction chromatography resin and was based on an uncommon apparatus with limited sample capacity for the separation step. The procedure also left the Zr fraction contaminated with the radioactive 90Y daughter nuclide. The present work investigates using an alternative separation scheme that utilizes a less costly resin in a widely available column configuration and results in the isolation of 90Sr’s stable granddaughter, 90Zr, without 90Y contamination. This allows the zirconium quantification to be done with a mass spectrometer outside the radiological environment and increases the number of instruments capable of making the measurement, which could allow measurements to be made more quickly.

Integration of a hyphenated HPIC-ICPMS protocol for the measurement of transplutonium isotopic mass distributions for 252Cf campaigns at Oak Ridge National Laboratory

ID: 1816
Year: 2018
Products: PFA-HS
Authors: Roach, B;Giaquinto, J;Keever, T;
Journal: J Radioanal Nucl Chem

Rapid measurement of transplutonium isotopic mass distributions during 252Cf production campaigns at Oak Ridge National Laboratory is a critical need. Mass measurements for the isotopes of plutonium, americium, curium, and californium are routinely requested to support the α-hydroxy-isobutyrate runs for the purification and recovery of the heavy curium target material and final 249Bk, 252Cf, and 254Es enriched isotope products. This paper presents the integration of an online high-pressure ion chromatography inductively coupled plasma mass spectrometry technique together with the protocol and chemistry that allows for rapid baseline separation and direct quantification of the transplutonium elemental concentrations and isotopic compositions.

What’s that yellow powder? A nuclear forensic case study

ID: 1815
Year: 2018
Products: Elemental Scientific Instrument (ESI, Omaha, NE, USA) micro-FAST system
Authors: Xu, N;Worley, C;Rim, J;Rearick, M;Labotka, D;Green, L;Walker, R;
Journal: J Radioanal Nucl Chem

In this paper the utilization of three analytical chemistry techniques including gamma spectrometry, XRF, and ICP-MS/OES is described for performing nuclear forensic analyses on an unknown powder. We have demonstrated that each method was unique in providing specific material characteristics, yet they were also complementary for extracting useful nuclear forensic signatures. It is the integral effort of all three analytical chemistry tools in the nuclear forensic tool box that ultimately allowed us to reveal the identity of the unknown nuclear material as Nb2O5 mixed with ~ 9% HEU.

Trace impurity analysis in uranium oxide via hybrid quantification techniques—gravimetric standard addition and isotope dilution mass spectrometry

ID: 1814
Year: 2018
Products: standard cyclonic double passing introduction system
Authors: Rogers, K;Giaquinto, J;Essex, R;Metzger, S;Ticknor, B;Hexel, C;
Journal: J Radioanal Nucl Chem

Measurement methods for the analysis of trace impurities in uranium materials, essential in nuclear fuel production and nuclear forensics, are continuously improving. Analytical methods were developed with the goal of lowering uncertainties of next generation certified uranium oxide reference materials for trace impurity concentrations. Through addition of a traceable standard directly into the sample, gravimetric standard addition and isotope dilution followed by analysis on an inductively coupled plasma mass spectrometer can achieve lower uncertainties. Results for 28 impurities in CRM 124-1 and 124-6 from NBL Program Office were used for validation of accuracy and comparisons of uncertainties.

Strontium isotope ratios (87 Sr/86 Sr) of human fingernail clippings reveal multiple location signals

ID: 1813
Year: 2018
Products: PrepFAST MC
Authors: Mancuso, CJ;Ehleringer, JR;
Journal: Rapid Commun. Mass Spectrom.

Strontium isotope ratios (87 Sr/86 Sr) in human fingernail keratin tissues have been underexplored for region of origin and travel history reconstruction studies. Here we investigated 87 Sr/86 Sr ratios in fingernail keratin to establish baseline measurements in a resident group and to examine how 87 Sr/86 Sr ratios changed with relocation. Fingernail clippings were collected from resident (n=10) and non-resident/traveler groups (n=4 and n=4) that were part of a larger study in Salt Lake City (UT, USA) from 2015 to 2016. Strontium abundance and 87 Sr/86 Sr ratios were determined via MC-ICP-MS. 87 Sr/86 Sr and oxygen (δ18 O) isotope ratios from the traveler participants were compared to examine temporal patterns. Strontium abundance and 87 Sr/86 Sr ratios in fingernails from the resident group established a baseline against which we could evaluate potential differences in non-resident/traveler groups. Resident 87 Sr/86 Sr ratios remained constant over the study period and were consistent with previously measured tap waters for the area. 87 Sr/86 Sr ratio changes in non-resident/traveler groups were rapid and reflected the current location of the individual within 4-5 weeks of arrival. Lastly, δ18 O and 87 Sr/86 Sr ratios of the same fingernail clippings did not exhibit similar temporal patterns, since fingernail δ18 O ratios required more time to attain values characteristic of the new environment. Our findings suggest that strontium is incorporated into fingernail tissues differently from hair and this could be advantageous to forensic investigations. We found that 87 Sr/86 Sr and δ18 O ratios of the same fingernail clippings revealed two different time points reflecting an individual's residence over a short (4-5 weeks, 87 Sr/86 Sr ratios) and long-term (3-5 months, δ18 O values) time scales. It is likely that the 87 Sr/86 Sr ratios of fingernail clippings reflect exogenous signals that are incorporated through bathing waters and that these signals change rapidly with movement to a new location. Our results may aid future forensic studies in the determination of region of origin in unidentified remains.

Trace element migration during UF4 bomb reduction: Implications to metal fuel production, worker health and safety, and nuclear forensics

ID: 1812
Year: 2018
Products: Elemental Scientific SC2 DX FAST auto-sampler interface
Authors: Reilly, D;Athon, M;Corbey, J;Leavy, I;McCoy, K;Schwantes, J;
Journal: Journal of Nuclear Materials

Understanding the migration of trace contaminants during the production of U metal is vital for fabricating advanced nuclear fuels, for managing worker health and safety at foundry and processing facilities, and for advancing nuclear forensic science. A common method used to produce actinide metals is the bomb reduction of suitable U precursors. Here, we report the results of a series of experiments designed to quantitatively track the trace contaminants Th, Ca, and Mg through a bomb reduction of UF4 using a vacuum induction furnace. In this series, UF4 charges were doped with elemental Th at 0 (a blank), 1, 10, 100, and 1000 ppm Th/U. Following reduction, the metal ingot products and the associated slag and crucibles were individually digested and analyzed using inductively coupled plasma-mass spectrometry. The results show that Th fractionation occurred at all concentrations but was most significant, and near quantitative, in samples starting with Th concentrations below 100 ppm. Thorium was found to incorporate into the slag and crucible in roughly equal proportions during reduction. A significant amount of U and Ca migrated into the crucible walls, each correlating positively with the quantities of Mg migrating from the MgO crucible to the U metal product.

Hair Mineral and Trace Element Content in Children with Down's Syndrome

ID: 1811
Year: 2018
Products: ESI SC-2 DX4 autosampler
Authors: Grabeklis, AR;Skalny, AV;Skalnaya, AA;Zhegalova, IV;Notova, SV;Mazaletskaya, AL;Skalnaya, MG;Tinkov, AA;
Journal: Biol Trace Elem Res

The objective of the present study was to assess the level of minerals and trace elements in 40 children with Down's syndrome and 40 controls aged 1-2 years old. Hair mineral and trace element analysis was performed using inductively coupled plasma mass spectrometry. The obtained data demonstrate that hair levels of Mg, P, I, Cr, Si, Zn, and Pb in Down's syndrome patients exceeded the respective control values by 36, 36, 93, 57, 45, 28, and 54%, whereas hair mercury was more than twofold lower in children with Down's syndrome. The observed difference in the levels of trace elements was age-dependent. In particular, in 1-year-olds, major differences were observed for essential elements (Cr, Si, Zn), whereas in 2-year-olds-for toxic elements (Hg, Pb). At the same time, hair P levels in Down's syndrome patients were 14 and 35% higher at the age of 1 and 2 years in comparison to the respective controls. Multiple regression analysis demonstrated that a model incorporating all elements, being characterized by a significant group difference, accounted for 42.5% of status variability. At the same time, only hair phosphorus was significantly interrelated with Down's syndrome status (β = 0.478; p < 0.001). Principal component analysis (PCA) used As, Ca, Cr, Fe, Hg, I, Mg, P, Pb, Se, Si, Sn, and Zn as predictors, with the resulting R2 = 0.559. The OPLS-DA models also separated between Down's and health control groups. Therefore, 1-2-year-old patients with Down's syndrome are characterized by significant alterations of mineral and trace element status.

Assessing the role of ontogenetic movement in maintaining population structure in fish using otolith microchemistry

ID: 1810
Year: 2018
Products: PC3
Authors: Wright, PJ;Régnier, T;Gibb, FM;Augley, J;Devalla, S;
Journal: Ecol Evol

Identifying the mechanisms maintaining population structure in marine fish species with more than a single dispersing life stage is challenging because of the difficulty in tracking all life stages. Here, a two-stage otolith microchemistry approach to examining life-stage movement was adopted, tracking a year-class from the juvenile to adult stage and inferring larval sources from clustering, in order to consider the mechanisms maintaining population structuring in North Sea cod. Clustering of near-core chemistry identified four clusters, two of which had either a southern or northern affinity and were similar to juvenile edge chemistry. The other two clusters, common to the central North Sea, had intermediate chemical composition and may have reflected either larval mixing in this region or a lack of geographic heterogeneity in the elemental signature. From the comparison of whole juvenile and the corresponding component of adult otoliths, adults from the southern North Sea mostly recruited from adjacent nursery grounds. In contrast, many adults in the northern North Sea had a juvenile chemistry consistent with the Skagerrak and juveniles from the northern Skagerrak site had a near-core chemistry consistent with the northern North Sea. Similarities in otolith chemistry were consistent with retention of early life stages at a regional level and also juvenile and adult fidelity. The links between the northern North Sea and Skagerrak indicate natal homing, which when considered in the context of genetic evidence is suggestive of philopatry. The approach used here should be useful in exploring the mechanisms underlying population structuring in other species with multiple dispersive life stages and calcified hard parts.

Migration path and isotope tracing of 137Cs and 239 + 240Pu in estuary sediments: a case study of Liao River estuary in China

ID: 1809
Year: 2018
Products: PEX-Q high efficiency sample intro- duction system
Authors: Zhang, K;Li, G;Pan, S;Qian, X;Liu, Z;Xu, Y;Hao, Y;
Journal: J Soils Sediments

Purpose Currently, the distribution characteristics and transport processes of the radionuclides 137Cs and 239 + 240Pu in the sediments of estuaries are still a controversial issue. Thus, in the present study, we investigated the distribution characteristics, sources and migration path of 137Cs and 239 + 240Pu in sediment cores of the Liao River estuary (LRE), China, and evaluated the relative contributions of the Pacific Proving Grounds (PPG) and riverine sources of Pu for the sediments in this area. We used 137Cs and Pu isotopes for dating the sediments and estimated the sedimentation rates by the two radionuclides in the LRE. Materials and methods Seven sediment samples were collected using a box corer from the Liao River estuarine wetland and tidal flat in the LRE in October 2012 and April 2015, respectively. The activities of 137Cs in the various samples were determined by γ spectrometry using HP-Ge detectors with 60% relative counting efficiency. Approximately 2–5 g of sediment were spiked with 242Pu (ca. 1 mBq) as a chemical yield tracer for Pu isotopic analysis at the School of Radiation Medicine and Protection, Soochow University. The measurement of Pu isotopes (239Pu, 240Pu, 242Pu) was performed by a sector field ICP-MS. In order to quantitatively differentiate the relative proportions of global fallout and PPG, we employed a two-end member mixing model to estimate their contributions. Results and discussion The average values of 137Cs, 239 + 240Pu activity concentrations, and 240Pu/239Pu atom ratios in the surface sediment samples of the LRE were 6.727 ± 0.251 mBq g−1, 0.294 ± 0.024 mBq g−1, and 0.188 ± 0.049 (1σ), respectively. The average 240Pu/239Pu atom ratios ranged from 0.180 ± 0.034 to 0.199 ± 0.021 in sediment cores from the east and west sides of the LRE. For core LT-2 values for 137Cs and 239 + 240Pu concentrations were from below the detection limit: 3.380 ± 0.414 and 0.036 ± 0.007 to 0.105 ± 0.007 mBq g−1. The mean 240Pu/239Pu atom ratio 0.217 ± 0.050 (1σ) in sediment core LT-2 lies between the global fallout and PPG close-in fallout. Conclusions We found that atmospheric fallout is the main source of Pu in sediment cores from the east and west sides of the LRE. For core LT-2, atmospheric fallout and riverine input (~ 73.4%) are the major sources of Pu with the source of the rest of Pu (~ 26.6%) attributed to the PPG via the Tsushima Warm Current and the coastal water of the East China Sea. The sedimentation rates (means 0.62–0.8 cm year−1) estimated by the two radionuclides were in good agreement and without any statistically significant difference.

Selenium and drinking water quality indicators in Mongolia

ID: 1808
Year: 2018
Products: ESI SC DX4 auto sampler
Authors: Golubkina, N;Erdenetsogt, E;Tarmaeva, I;Brown, O;Tsegmed, S;
Journal: Environ Sci Pollut Res Int

Mongolia is characterized by restricted sources of drinking water and intensive water pollution due to high rates of urbanization, mining industry development, enormous amount of livestock, and ever-growing attempts in domestic production of cereals and vegetables. Among others, Se is the least studied element in Mongolian water resources. Based on fluorimetric method of analysis, the first results on Se levels in drinking water of five aimags, Ulaanbaatar, and Erdenet were obtained. Uneven distribution of Se in Mongolia was manifested, the highest Se concentrations being typical for the southern resources (up to 18,600 μg/L) and the lowest, for the Northern ones (up to 0.022 μg/L). ICP-MS data of Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, Hg, I, K, Li, Mg, Mn, Na, Ni, P, Pb, Si, Sn, Sr, V, and Zn contents indicate poly-microelementosis existence in the South of Mongolia (Dorno-Gobi aimag) where ground water is characterized by elevated levels of As and extremely high levels of Se, Li, Na, F, Cl, B, and nitrates ions, exceeding maximum permissible levels by 1.86; 4.3; 3.1; 3.1; 2.7; 3.4; and 1.8 times respectively. Toxic concentrations of Se in groundwater of Dorno-Gobi aimag contradict with the published low human serum Se and low content of the element in horseflesh that suggests the possible effect of the above pollutants on Se bioavailability. Revealed phenomenon and mosaic distribution of heavy metals in areas with high and low Se content in water resources indicate the need of direct search for Se and other pollutant transfer in food chain in various ecological loading conditions, creation of a map of Se distribution in water resources of other Mongolian regions, and large-scale evaluation of the human poly-elemental status.

Nickel exposure reduces enterobactin production in Escherichia coli

ID: 1807
Year: 2018
Products: cyclonic spray chamber
Authors: Washington-Hughes, CL;Ford, GT;Jones, AD;McRae, K;Outten, FW;
Journal: Microbiologyopen

Escherichia coli is a well-studied bacterium that can be found in many niches, such as industrial wastewater, where the concentration of nickel can rise to low-millimolar levels. Recent studies show that nickel exposure can repress pyochelin or induce pyoverdine siderophore production in Pseudomonas aueroginosa. Understanding the molecular cross-talk between siderophore production, metal homeostasis, and metal toxicity in microorganisms is critical for designing bioremediation strategies for metal-contaminated sites. Here, we show that high-nickel exposure prolongs lag phase duration as a result of low-intracellular iron levels in E. coli. Although E. coli cells respond to low-intracellular iron during nickel stress by maintaining high expression of iron uptake systems such as fepA, the demand for iron is not met due to a lack of siderophores in the extracellular medium during nickel stress. Taken together, these results indicate that nickel inhibits iron accumulation in E. coli by reducing the presence of enterobactin in the extracellular medium.

Stoichiometry, polarity, and organometallics in solid-phase extracted dissolved organic matter of the Elbe-Weser estuary

ID: 1806
Year: 2018
Products: Apex Q
Authors: Ksionzek, KB;Zhang, J;Ludwichowski, KU;Wilhelms-Dick, D;Trimborn, S;Jendrossek, T;Kattner, G;Koch, BP;
Journal: PLoS ONE

Dissolved organic matter (DOM) is ubiquitous in natural waters and plays a central role in the biogeochemistry in riverine, estuarine and marine environments. This study quantifies and characterizes solid-phase extractable DOM and trace element complexation at different salinities in the Weser and Elbe River, northern Germany, and the North Sea. Dissolved organic carbon (DOC), total dissolved nitrogen (TDN), Co and Cu concentrations were analyzed in original water samples. Solid-phase extracted (SPE) water samples were analyzed for DOC (DOCSPE), dissolved organic nitrogen (DONSPE), sulfur (DOSSPE) and trace metal (51V, 52Cr, 59Co, 60Ni, 63Cu, 75As) concentrations. Additionally, different pre-treatment conditions (acidification vs. non-acidification prior to SPE) were tested. In agreement with previous studies, acidification led to generally higher recoveries for DOM and trace metals. Overall, higher DOM and trace metal concentrations and subsequently higher complexation of trace metals with carbon and sulfur-containing organic complexes were found in riverine compared to marine samples. With increasing salinity, the concentrations of DOM decreased due to estuarine mixing. However, the slightly lower relative decrease of both, DOCSPE and DONSPE (~77%) compared to DOSSPE (~86%) suggests slightly faster removal processes for DOSSPE. A similar distribution of trace metal and carbon and sulfur containing DOM concentrations with salinity indicates complexation of trace metals with organic ligands. This is further supported by an increase in Co and Cu concentration after oxidation of organic complexes by UV treatment. Additionally, the complexation of metals with organic ligands (analyzed by comparing metal/DOCSPE and metal/DOSSPE ratios) decreased in the order Cu > As > Ni > Cr > Co and thus followed the Irving-Williams order. Differences in riverine and marine trace metal containing DOMSPE are summarized by their average molar ratios of (C107N4P0.013S1)1000V0.05Cr0.33Co0.19Ni0.39Cu3.41As0.47 in the riverine endmember and (C163N7P0.055S1)1000V0.05Cr0.47Co0.16Ni0.07Cu4.05As0.58 in the marine endmember.

Assessing the stability of Cd, Mn, Pb, Se, and total Hg in whole human blood by ICP-DRC-MS as a function of temperature and time

ID: 1805
Year: 2018
Products: ESI SC4 autosampler
Authors: Tevis, DS;Jarrett, JM;Jones, DR;Cheng, PY;Franklin, M;Mullinex, N;Caldwell, KL;Jones, RL;
Journal: Clin. Chim. Acta

Comprehensive information on the effect of time and temperature storage on the measurement of elements in human, whole blood (WB) by inductively coupled plasma-dynamic reaction cell-mass spectrometry (ICP-DRC-MS) is lacking, particularly for Mn and Se. Human WB was spiked at 3 concentration levels, dispensed, and then stored at 5 different temperatures: -70 °C, -20 °C, 4 °C, 23 °C, and 37 °C. At 3 and 5 weeks, and at 2, 4, 6, 8, 10, 12, 36 months, samples were analyzed for Pb, Cd, Mn, Se and total Hg, using ICP-DRC-MS. We used a multiple linear regression model including time and temperature as covariates to fit the data with the measurement value as the outcome. We used an equivalence test using ratios to determine if results from the test storage conditions, warmer temperature and longer time, were comparable to the reference storage condition of 3 weeks storage time at -70 °C. Model estimates for all elements in human WB samples stored in polypropylene cryovials at -70 °C were equivalent to estimates from samples stored at 37 °C for up to 2 months, 23 °C up to 10 months, and -20 °C and 4 °C for up to 36 months. Model estimates for samples stored for 3 weeks at -70 °C were equivalent to estimates from samples stored for 2 months at -20 °C, 4 °C, 23 °C and 37 °C; 10 months at -20 °C, 4 °C, and 23 °C; and 36 months at -20 °C and 4 °C. This equivalence was true for all elements and pools except for the low concentration blood pool for Cd. Storage temperatures of -20 °C and 4 °C are equivalent to -70 °C for stability of Cd, Mn, Pb, Se, and Hg in human whole blood for at least 36 months when blood is stored in sealed polypropylene vials. Increasing the sample storage temperature from -70 °C to -20 °C or 4 °C can lead to large energy savings. The best analytical results are obtained when storage time at higher temperature conditions (e.g. 23 °C and 37 °C) is minimized because recovery of Se and Hg is reduced. Blood samples stored in polypropylene cryovials also lose volume over time and develop clots at higher temperature conditions (e.g., 23 °C and 37 °C), making them unacceptable for elemental testing after 10 months and 2 months, respectively. Published by Elsevier B.V.

Mercury Inputs to Chinese Marginal Seas: Impact of Industrialization and Development of China

ID: 1804
Year: 2018
Products: Apex-Q desolvation unit
Authors: Yin, R;Guo, Z;Hu, L;Liu, W;Hurley, J;Lepak, R;Lin, T;Feng, X;Li, X;
Journal: J. Geophys. Res. Oceans

In the past decades, China has experienced substantial economic growth and industrialization. However, the effects of vast development of China on Hg input to the nearby oceans are still unclear. In this study, the influx and isotopic compositions of Hg in four 210Pb‐dated sediment cores were examined to investigate changes in Hg deposition to the marginal seas off China over a century. Nearshore cores had higher Hg influxes than offshore cores. Increases of Hg influxes started since the 1950s, which coincides with China's economic development. Dramatic historical changes in Hg isotopic composition were observed in the cores (δ202Hg: −2.01‰ to −0.69‰; Δ199Hg: −0.16‰ to 0.31‰; n = 106). δ202Hg increased from the deep to the surface layers of the cores. The offshore cores mainly showed positive Δ199Hg values, but the pre‐1950 samples had more positive Δ199Hg values than the younger samples. The nearshore cores mainly showed negative Δ199Hg values in the pre‐1950s samples, but the younger samples showed Δ199Hg values close to zero. A triple‐mixing isotope model, used to quantify the contribution of potential Hg inputs (e.g., direct discharge of industrial Hg, soil Hg, and precipitation‐derived Hg), showed clear evidence of enhanced industrial Hg inputs to the ocean margin, but slightly decreased watershed soil Hg inputs in the last few decades. The variations of watershed‐derived Hg were likely caused by the construction of impoundments in major rivers of China. This study demonstrates that mercury inputs to Chinese marginal seas have been largely altered due to the industrialization and economic development of China.

Sustained Upwelling of Subsurface Iron Supplies Seasonally Persistent Phytoplankton Blooms Around the Southern Kerguelen Plateau, Southern Ocean

ID: 1803
Year: 2018
Products: SeaFAST S2 pico
Authors: Schallenberg, C;Bestley, S;Klocker, A;Trull, T;Davies, D;Gault-Ringold, M;Eriksen, R;Roden, N;Sander, S;Sumner, M;Townsend, A;van der Merwe, P;Westwood, K;Wuttig, K;Bowie, A;
Journal: J. Geophys. Res. Oceans

Although the supply of iron generally limits phytoplankton productivity in the Southern Ocean, substantial seasonal blooms are observed over and downstream of the Kerguelen plateau in the Indian sector of the Southern Ocean. Surprisingly, of the oceanic blooms, those associated with the deeper southern plateau last much longer (~3 months) than the northern bloom (~1‐month downstream of northern plateau). In this study, iron supply mechanisms around the southern plateau were investigated, obtaining profiles of dissolved iron (<0.2 μm, dFe) to 2,000‐m deep at 25 stations during austral summer 2016. The dFe concentrations in surface waters (≤100‐m depth) ranged from below the detection limit (DL, median of 0.026 nmol/kg) to 0.34 nmol/kg near the Antarctic shelf, with almost half the data points below detection. These low and—with few exceptions—largely spatially invariant concentrations, presumably driven by seasonal drawdown of this essential micronutrient by phytoplankton, could not explain observed patterns in chlorophyll a. In contrast, dFe concentrations (0.05–1.27 nmol/kg) in subsurface waters (100–800 m) showed strong spatial variations that can explain bloom patterns around the southern Kerguelen plateau when considered in the context of frontal locations and associated frontal processes, including upwelling, that may increase the upward supply of dFe in the region. This sustained vertical dFe supply distinguishes the southern blooms from the bloom downstream of the northern Kerguelen plateau and explains their persistence through the season.

Particulate Trace Metal Composition and Sources in the Kuroshio Adjacent to the East China Sea: The Importance of Aerosol Deposition

ID: 1802
Year: 2018
Products: SC-Fast autosampler
Authors: Liao, W;Ho, T;
Journal: J. Geophys. Res. Oceans

The Kuroshio, flowing through the eastern end of the East China Sea, transports terrestrial material to the Northwestern Pacific Ocean. Along the Kuroshio path, we collected size‐fractionated suspended particles in the upper 200 m to investigate the composition and sources of particulate trace metals. Demonstrated by Al‐ and P‐normalized elemental ratios, we found that anthropogenic aerosol deposition was the major source of most particulate trace metals in the Kuroshio region although the impact of bottom resuspension and riverine input may be significant at some specific regions. As seen in our previous studies in the South China Sea and the Western Philippine Sea, this study concluded that anthropogenic aerosol deposition is the dominant particulate trace metal source in the surface water of the Northwestern Pacific Ocean and its marginal seas. Compared to particulate trace metal composition obtained in other open oceans, we found that the distribution patterns of particulate trace metal composition in the surface waters are closely associated with aerosol deposition fluxes. In regions with low deposition, the particulate trace metal concentrations were extremely low and metal to P ratios were all comparable to their intracellular quota previously proposed. In regions with high deposition, metal to P ratios were highly elevated in comparison to their intracellular quota and metal to Al ratios were deviated from lithogenic ratios to various extents. The globally consistent distribution patterns validate trace metal stoichiometry concept in plankton intracellularly and the primary role of aerosol deposition on deciding particulate trace metal composition in oceanic surface water globally.

Quantitative dried blood spot analysis for metallodrugs by laser ablation-inductively coupled plasma-mass spectrometry

ID: 1801
Year: 2018
Products: SC4-SL
Authors: Kröger, S;Sperling, M;Karst, U;
Journal: Journal of Trace Elements in Medicine and Biology

A quantitative dried blood spot (DBS) method based on direct sampling by means of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is presented. Gadolinium-based contrast agents were used as model metallodrugs with a significant relevance for pharmaceutical applications. Challenges regarding the ablation of the complex blood-filter matrix were characterized and successfully addressed by a thorough adaption of the laser ablation conditions. Especially the laser fluence was optimized with respect to the particle size distribution of the generated aerosol as monitored by an optical particle counter. Thus, generation of micrometer-sized particles could be minimized in favor of smaller particles increasing the transport efficiency of the DBS ablation aerosol to the plasma and the recorded signal stability. Inhomogeneous blood drying on the porous filter paper could be compensated by the addition of an internal standard prior to blood spotting. To preserve the advantages of DBS sampling, such as small blood volumes and minimal invasiveness, the combined use of DBS and a capillary blood sampling system is demonstrated. By placing the internal standard into the capillary prior to blood sampling, a simple workflow usable for clinical application was implemented. The applicability of the developed method, achieving limits of detection and quantification in the low µg∙L-1 range and covering a linear range of over four orders of magnitude, was demonstrated for blood samples containing different concentrations of the gadolinium contrast agents gadopentetate and gadoterate.


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