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Sample records for traces mass lensperfect

  1. Trace amount analysis using spark mass spectrometry

    International Nuclear Information System (INIS)

    Stefani, Rene

    1975-01-01

    Characteristics of spark mass spectrometers (ion source, properties of the ion beam, ion optics, and performance) and their use in qualitative and quantitative analysis are described. This technique is very interesting for the semi-quantitative analysis of trace amounts, down to 10 -8 atoms. Examples of applications such as the analysis of high purity materials and non-conducting mineral samples, and determination of carbon and gas trace amounts are presented. (50 references) [fr

  2. Contour tracing for segmentation of mammographic masses

    International Nuclear Information System (INIS)

    Elter, Matthias; Held, Christian; Wittenberg, Thomas

    2010-01-01

    CADx systems have the potential to support radiologists in the difficult task of discriminating benign and malignant mammographic lesions. The segmentation of mammographic masses from the background tissue is an important module of CADx systems designed for the characterization of mass lesions. In this work, a novel approach to this task is presented. The segmentation is performed by automatically tracing the mass' contour in-between manually provided landmark points defined on the mass' margin. The performance of the proposed approach is compared to the performance of implementations of three state-of-the-art approaches based on region growing and dynamic programming. For an unbiased comparison of the different segmentation approaches, optimal parameters are selected for each approach by means of tenfold cross-validation and a genetic algorithm. Furthermore, segmentation performance is evaluated on a dataset of ROI and ground-truth pairs. The proposed method outperforms the three state-of-the-art methods. The benchmark dataset will be made available with publication of this paper and will be the first publicly available benchmark dataset for mass segmentation.

  3. A mass spectrometer based explosives trace detector

    Science.gov (United States)

    Vilkov, Andrey; Jorabchi, Kaveh; Hanold, Karl; Syage, Jack A.

    2011-05-01

    In this paper we describe the application of mass spectrometry (MS) to the detection of trace explosives. We begin by reviewing the issue of explosives trace detection (ETD) and describe the method of mass spectrometry (MS) as an alternative to existing technologies. Effective security screening devices must be accurate (high detection and low false positive rate), fast and cost effective (upfront and operating costs). Ion mobility spectrometry (IMS) is the most commonly deployed method for ETD devices. Its advantages are compact size and relatively low price. For applications requiring a handheld detector, IMS is an excellent choice. For applications that are more stationary (e.g., checkpoint and alternatives to IMS are available. MS is recognized for its superior performance with regard to sensitivity and specificity, which translate to lower false negative and false positive rates. In almost all applications outside of security where accurate chemical analysis is needed, MS is usually the method of choice and is often referred to as the gold standard for chemical analysis. There are many review articles and proceedings that describe detection technologies for explosives. 1,2,3,4 Here we compare MS and IMS and identify the strengths and weaknesses of each method. - Mass spectrometry (MS): MS offers high levels of sensitivity and specificity compared to other technologies for chemical detection. Its traditional disadvantages have been high cost and complexity. Over the last few years, however, the economics have greatly improved and MS is now capable of routine and automated operation. Here we compare MS and IMS and identify the strengths and weaknesses of each method. - Ion mobility spectrometry (IMS): 5 MS-ETD Screening System IMS is similar in concept to MS except that the ions are dispersed by gas-phase viscosity and not by molecular weight. The main advantage of IMS is that it does not use a vacuum system, which greatly reduces the size, cost, and complexity

  4. Inorganic trace analysis by laser ionization mass spectrometry

    International Nuclear Information System (INIS)

    Becker, S.; Dietze, H.J.

    1991-01-01

    Among the different spectrometric techniques for trace analysis Laser Ionization Mass Spectrometry (LIMS) is well established as a trace analytic method with a wide coverage. In the LIMS the sample material is evaporated and ionized by means of a focused pulsed laser beam in a laser microplasma, which is formed in the spot area of the irradiated sample. All chemical elements in the sample materials are evaporated and ionized in the laser plasma. The formed ions are separated according to mass and energy by a time-of-flight, quadrupole or double focusing mass spectrometer. In this review the characteristics and analytical features, some recent developments, and applications of laser ionization mass spectrometry in inorganic trace analysis are described. (orig.)

  5. Laser ionization mass spectrometry in inorganic trace analysis

    International Nuclear Information System (INIS)

    Becker, J.S.; Dietze, H.J.

    1992-01-01

    Among the different spectrometric techniques for trace analysis Laser Ionization Mass Spectrometry (LIMS) is well established as a trace analytical method. With the LIMS technique the sample material is evaporated and ionized by means of a focused pulsed laser in a laser microplasma, which is formed in the spot area of the irradiated sample. All chemical elements in the sample materials are evaporated and ionized in the laser plasma. The ions formed are separated according to their mass and energy by a time-of-flight, quadrupole or double focusing mass spectrometer. In this review the characteristics and analytical features, some recent developments and applications of laser ionization mass spectrometry in inorganic trace analysis are described. (orig.)

  6. Using the ion microprobe mass analyser for trace element analysis

    International Nuclear Information System (INIS)

    Schilling, J.H.

    1978-01-01

    Most techniques for the analysis of trace elements are capable of determining the concentrations in a bulk sample or solution, but without reflecting their distribution. In a bulk analysis therefore elements which occur in high concentration in a few precipitates would still be considered trace elements even though their local concentration greatly exceed the normally accepted trace elements concentration limit. Anomalous distribution is also shown by an oxide layer, a few hundred Angstrom thick, on an aluminium sample. A low oxide concentration would be reported if it were included in the bulk analysis, which contradicts the high surface concentration. The importance of a knowledge of the trace element distribution is therefore demonstrated. Distributional trace element analysis can be carried out using the ion microprobe mass analyser (IMMA). Since the analytical technique used in this instrument, namely secondary ion mass spectrometry (SIMS), is not universally appreciated, the instrument and its features will be described briefly followed by a discussion of quantitative analysis and the related subjects of detection limit and sample consumption. Finally, a few examples of the use of the instrument are given

  7. Radio-tracing 'without' radioactivity: accelerator mass spectrometry in biomedicine

    International Nuclear Information System (INIS)

    Vogel, J.S.

    2005-01-01

    Accelerator mass spectrometry (AMS) is a form of isotope-ratio mass spectrometry that quantifies concentrations of certain long-lived radioisotopes independently of their radioactive decay. AMS is primarily used in the geosciences for determining the age of a material that contains naturally occurring radioisotopes. AMS uses the same high specificity for enriched levels of these radioisotopes in tracing low chemical doses for long periods in biological systems, including humans. AMS provides the safety of low radiative exposure to experimental subjects and investigators, while obtaining attomole sensitivities that are not possible with stable isotope tracers because of their natural isotopic abundances. AMS isotope tracing was first applied to quantifying the genotoxicity of low level environmental chemicals in animals and later in humans. Physiologic concentrations of 14 C-labeled trace nutrients (folate, carotene, and tocopherol) are now measured directly in humans without concern about radiation. The radiative exposure is less than the commonly accepted risks of natural background radiation or the radiation fields found in high altitude air flights. AMS measures very small biological samples (such as 20 microliters of blood) that are easily obtained from human volunteers or model animals at frequent intervals for detailed analysis of kinetic profiles. This high data density enables the construction of compartmental models that elucidate nutrient behavior in tissues that cannot be directly sampled. The pharmaceutical industry is enthusiastic about AMS as a detector for 'micro-dosing' in which the human kinetics of an assuredly non-toxic dose of a candidate drug is tested early in a development project. Molecular tracing uses 3 H or 14 C as common isotopic labels, but AMS contributes to elemental tracing with certain radioisotopes having very long lives, such as 26 AL or 41 Ca. Calcium-41 is a particularly useful isotope in biomedical research because it is used

  8. Determination of trace elements by resonant ionization mass spectrometry (RIMS)

    International Nuclear Information System (INIS)

    Ruster, W.; Ames, F.; Rehklau, D.; Mang, M.; Muehleck, C.; Rimke, H.; Sattelberger, P.; Herrmann, G.; Trautmann, N.; Kluge, H.J.; Otten, E.W.

    1988-01-01

    A resonant ionization mass spectrometer has been developed as an analytical tool for the detection of trace elements, especially of plutonium and other radionuclides. The sample, deposited on a rhenium filament, is evaporated by electrical heating and the atoms of the element under investigation are selectively ionized by laser light delivered from three dye lasers pumped by a copper vapour laser. The resulting photoions are detected in a time-of-flight spectrometer with a channelplate detector. For plutonium a mass resolution of M/ΔM=1500 was obtained and an overall detection efficiency of 4x10 -6 was determined for stepwise excitation and ionization via autoionizing states. With a laser light bandwidth of 3-5 GHz neighbouring isotopes could be suppressed by a factor of 20 due to isotope shifts in the excitation transitions. The isotope composition of synthetic samples was measured and good agreement was found with mass spectroscopic results. The influence of the hyperfine structure on the isotope ratios is discussed. (orig.)

  9. Determination of trace and ultra-trace elements in Dergaon meteorite by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Balaram, V.; Gnaneswara Rao, T.; Anjaiah, K.V.; Phukon, N.; Majumdar, A.C.

    2003-01-01

    In this paper, a detailed methodology for high precision measurement of several trace and ultra-trace elements including REE and PGE have been presented using effective sample preparation techniques and inductively coupled plasma mass spectrometry. Discussion is focussed on aspects, such as total dissolution and recovery of all elements, minimization of oxide and doubly-charged and other polyatomic ion interferences, calibration by matrix matching standards, accuracy and precision

  10. A new method for automated discontinuity trace mapping on rock mass 3D surface model

    Science.gov (United States)

    Li, Xiaojun; Chen, Jianqin; Zhu, Hehua

    2016-04-01

    This paper presents an automated discontinuity trace mapping method on a 3D surface model of rock mass. Feature points of discontinuity traces are first detected using the Normal Tensor Voting Theory, which is robust to noisy point cloud data. Discontinuity traces are then extracted from feature points in four steps: (1) trace feature point grouping, (2) trace segment growth, (3) trace segment connection, and (4) redundant trace segment removal. A sensitivity analysis is conducted to identify optimal values for the parameters used in the proposed method. The optimal triangular mesh element size is between 5 cm and 6 cm; the angle threshold in the trace segment growth step is between 70° and 90°; the angle threshold in the trace segment connection step is between 50° and 70°, and the distance threshold should be at least 15 times the mean triangular mesh element size. The method is applied to the excavation face trace mapping of a drill-and-blast tunnel. The results show that the proposed discontinuity trace mapping method is fast and effective and could be used as a supplement to traditional direct measurement of discontinuity traces.

  11. A new method for automatic discontinuity traces sampling on rock mass 3D model

    Science.gov (United States)

    Umili, G.; Ferrero, A.; Einstein, H. H.

    2013-02-01

    A new automatic method for discontinuity traces mapping and sampling on a rock mass digital model is described in this work. The implemented procedure allows one to automatically identify discontinuity traces on a Digital Surface Model: traces are detected directly as surface breaklines, by means of maximum and minimum principal curvature values of the vertices that constitute the model surface. Color influence and user errors, that usually characterize the trace mapping on images, are eliminated. Also trace sampling procedures based on circular windows and circular scanlines have been implemented: they are used to infer trace data and to calculate values of mean trace length, expected discontinuity diameter and intensity of rock discontinuities. The method is tested on a case study: results obtained applying the automatic procedure on the DSM of a rock face are compared to those obtained performing a manual sampling on the orthophotograph of the same rock face.

  12. Quantitative determination of minor and trace elements in rocks and soils by spark source mass spectrometry

    International Nuclear Information System (INIS)

    Ure, A.M.; Bacon, J.R.

    1978-01-01

    Experimental details are given of the quantitative determination of minor and trace elements in rocks and soils by spark source mass spectrometry. The effects of interfering species, and corrections that can be applied, are discussed. (U.K.)

  13. Analysis of trace gases at ppb levels by proton transfer reaction mass spectrometry (PTR-MS)

    International Nuclear Information System (INIS)

    Lindinger, W.; Hansel, A.

    1996-01-01

    A proton transfer reaction mass spectrometry (PTR-MS) system has been developed which allows for on-line measurements of trace gas components with concentrations as low as 1 ppb. The method is based on reactions of H 3 O + ions, which perform non-dissociative proton transfer to most of the common organic trace constituents but do not react with any of the components present in clean air. Examples of medical information obtained by means of breath analysis, of environmental trace analysis, and examples in the field of food chemistry demonstrate the wide applicability of the method. (Authors)

  14. Mass spectrometric methods for trace analysis of metals

    International Nuclear Information System (INIS)

    Bahr, U.; Schulten, H.R.

    1981-01-01

    A brief outline is given of the principles of mass spectrometry (MS) and the fundamentals of qualitative and quantitative mass spectrometric analysis emphasizing recent developments and results. Classical methods of the analysis of solids, i.e. spark-source MS and thermal ionization MS, as well as recent methods of metal analysis are described. Focal points in this survey of recently developed techniques include secondary ion MS, laser probe MS, plasma ion source MS, gas discharge MS and field desorption MS. Here, a more detailed description is given and the merits of these emerging methods are discussed more explicitly. In particular, the results of the field desorption techniques in elemental analyses are reviewed and critically evaluated

  15. Applications of mass spectrometry in the trace element analysis of biological materials

    International Nuclear Information System (INIS)

    Moens, L.

    1997-01-01

    The importance of mass spectrometry for the analysis of biological material is illustrated by reviewing the different mass spectrometric methods applied and describing some typical applications published recently. Though atomic absorption spectrometry is used in the majority of analyses of biological material, most mass spectrometric methods have been used to some extent for trace element determination in biomedical research. The relative importance of the different methods is estimated by reviewing recent research papers. It is striking that especially inductively coupled plasma mass spectrometry is increasingly being applied, partly because the method can be used on-line after chromatographic separation, in speciation studies. Mass spectrometric methods prove to offer unique possibilities in stable isotope tracer studies and for this purpose also experimentally demanding methods such as thermal ionization mass spectrometry and accelerator mass spectrometry are frequently used. (orig.)

  16. Characterization and mass balance of trace elements in an iron ore sinter plant

    Directory of Open Access Journals (Sweden)

    Lucas Ladeira Lau

    2016-04-01

    Full Text Available Environmental legislation is becoming more restrictive in several industrial sectors, especially in the steel industry, which is well known for its large pollution potential. With the recent growth of interest in effects of trace elements on the environment and health, the inclusion of emission limits on these elements in this legislation has become increasingly popular. This article aims to describe the partitioning of trace elements between the products (sinter and plant emissions in an iron ore sinter plant, aiming to better understand the behavior of these elements in the sintering process to eventually support interventions to modify these partitions. Chemical characterization of several sintering inputs was initially performed, revealing that the steel-making residues contained large concentrations of trace elements, whereas low concentrations were observed in the flux. Based on the trace element concentrations, we analyzed the injection of trace elements in a sintering pilot using a sintering mixture. Mass balance was then used to determine the theoretical partitioning of trace elements in the sinter and emissions; cadmium, nickel, lead, mercury, and copper exhibited greater tendencies to concentrate in atmospheric emissions.

  17. Determination of trace amounts of impurities in molybdenum by spark source and glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Saito, Morimasa

    1994-01-01

    For the determination of trace and ultra-trace amounts of impurities in high-purity molybdenum, spark source mass spectrometry and glow discharge mass spectrometry were studied. In spark source mass spectrometry using the metal probe method, the liquid-helium cryogenic pump was used in order to protect the surface of the samples from oxidation. The theoretical relative sensitivity factors (Mo=1) calculated from physical properties were used. The analytical results obtained for molybdenum tablet and high-purity molybdenum were in good agreement with those obtained by other methods (atomic absorption spectrometry and others). In glow discharge mass spectrometry, the relative sensitivity factors were calculated by using the results obtained by spark source mass spectrometry and atomic absorption spectrometry, and this method was applied to the determination of ultra-trace amounts of impurities in ultra high-purity molybdenum and gave the satisfactory results. The detection limits (2σ, n=10) in the integration time of 600 s for U and Th were 0.6 ppb and 0.3 ppb, and the values for Al, Si, Cr, Mn and Cu were in the range of 10 ppb to 0.5 ppb. (author)

  18. Texture one zero Dirac neutrino mass matrix with vanishing determinant or trace condition

    Science.gov (United States)

    Singh, Madan

    2018-06-01

    In the light of non-zero and relatively large value of rector mixing angle (θ13), we have performed a detailed analysis of texture one zero neutrino mass matrix Mν in the scenario of vanishing determinant/trace conditions, assuming the Dirac nature of neutrinos. In both the scenarios, normal mass ordering is ruled out for all the six possibilities of Mν, however for inverted mass ordering, only two are found to be viable with the current neutrino oscillation data at 3σ confidence level. Numerical and some approximate analytical results are presented.

  19. Trace and surface analysis of ceramic layers of solid oxide fuel cells by mass spectrometry.

    Science.gov (United States)

    Becker, J S; Breuer, U; Westheide, J; Saprykin, A I; Holzbrecher, H; Nickel, H; Dietze, H J

    1996-06-01

    For the trace analysis of impurities in thick ceramic layers of a solid oxide fuel cell (SOFC) sensitive solid-state mass spectrometric methods, such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and radiofrequency glow discharge mass spectrometry (rf-GDMS) have been developed and used. In order to quantify the analytical results of LA-ICP-MS, the relative sensitivity coefficients of elements in a La(0.6)Sr(0.35)MnO(3) matrix have been determined using synthetic standards. Secondary ion mass spectrometry (SIMS) - as a surface analytical method - has been used to characterize the element distribution and diffusion profiles of matrix elements on the interface of a perovskite/Y-stabilized ZrO(2) layer. The application of different mass spectrometric methods for process control in the preparation of ceramic layers for the SOFC is described.

  20. High precision analysis of trace lithium isotope by thermal ionization mass spectrometry

    International Nuclear Information System (INIS)

    Tang Lei; Liu Xuemei; Long Kaiming; Liu Zhao; Yang Tianli

    2010-01-01

    High precision analysis method of ng lithium by thermal ionization mass spectrometry is developed. By double-filament measurement,phosphine acid ion enhancer and sample pre-baking technique,the precision of trace lithium analysis is improved. For 100 ng lithium isotope standard sample, relative standard deviation is better than 0.086%; for 10 ng lithium isotope standard sample, relative standard deviation is better than 0.90%. (authors)

  1. Resonant laser mass spectrometry for environmental and industrial chemical trace analysis

    International Nuclear Information System (INIS)

    Boesl, Ulrich; Rink, Joerg; Distelrath, Volker; Pueffel, Peter

    2001-01-01

    A promising new method for pollutant trace analysis is resonant laser mass spectrometry. It combines selectivity, sensitivity, and speed of measurement. In this paper, two examples of application are presented: exhaust analysis of combustion engines and analysis of polycylcic aromatic compounds in soil samples. The sensitivity of small, mobile instruments is discussed as well as alternative laser-based techniques in the case formation of cations by nanosecond lasers is improbable

  2. Analysis of trace elements by means of accelerator secondary ion mass spectrometry

    International Nuclear Information System (INIS)

    Ender, R.M.

    1997-01-01

    The analysis of material composition and trace element concentration is of increasing interest primarily in semiconductor technology but also in metallurgy, geology, biology and medicine. At present, Secondary Ion Mass Spectrometry (SIMS) is in many respects the best technique to provide 3-dimensional information on the distribution of trace elements with concentrations below 1 ppm. However, due to the presence of molecular ions the detectability of many trace elements it restricted because of molecular mass interferences. In addition, detectors used in SIMS have a background counting rate of 0.1-1 Hz, which further limits trace element analysis. In Accelerator Mass Spectrometry (AMS) long-lived radionuclides are detected free of molecular interferences and detector background at isotopic ratios as low as 10 -15 . Moreover, isobaric interferences can be reduced as well. In order to benefit from these advantages a combination of SIMS and AMS (Accelerator SIMS) has been proposed almost 20 years ago, but no facility has ever been fully developed. It has been the aim of this work to add a new sputtering chamber for AMS measurements of ultrapure semiconductor material to the existing PSI/ETH AMS facility. To fulfill the requirements of material analysis, an UHV chamber with special precautions against contamination has been built and adapted to the existing AMS setup. For sputtering, a commercial Cs gun with an ExB filter and a 1 o beam bend for neutral particle suppression is used to obtain a pure Cs ion beam. The gun is equipped with different apertures for varying the diameter of the beam spot. With the integrated scanning unit the 10 keV Cs beam can be rastered over approximately 1 mm 2 . This allows different applications such as bulk analysis, depth profiling and imaging. The secondary ion extraction is matched to the ion optical and geometrical requirements of the existing accelerator mass spectrometer. (author) figs., tabs., 67 refs

  3. The measurement of mass spectrometric peak height ratio of helium isotope in trace samples

    International Nuclear Information System (INIS)

    Sun Mingliang

    1989-01-01

    An experiment study on the measurement of mass spectrometric peak height ratio of helium isotope in the trace gaseous sample is discussed by using the gas purification line designed by the authors and model VG-5400 static-vacuum noble gas mass spectrometer imported and air helium as a standard. The results show that the amount of He and Ne in natural gas sample is 99% after purification. When the amount of He in Mass Spectrometer is more than 4 x 10 -7 cm 3 STP, it's sensitivity remains stable, about 10 -4 A/cm 3 STP He and the precision of 3 He/ 4 He ratio within the following 17 days is 1.32%. The 'ABA' pattern and experiment condition in the measurement of mass spectrometric peak height ratio of He isotope are presented

  4. Application of resonance ionization mass spectrometry for trace analysis and in fundamental research

    International Nuclear Information System (INIS)

    Passler, G.

    1997-01-01

    Resonance ionization mass spectrometry (RIMS) has been used for ultra-trace analysis on long-lived radioisotopes like Pu, Tc and 89,90 Sr in various environmental samples. The experimental approaches cover pulsed laser spectroscopy on a thermal atomic beam and subsequent time-of-flight mass analysis, a pulsed laser ion source combined with conventional mass spectrometry, and collinear resonance ionization on a mass-separated fast atomic beam. The high sensitivity of RIMS also enables atomic spectroscopy on rare isotopes. For the first time experimental values for the ionization potential of actinides up to Cf have been determined. The paper reviews the dependency of the different experimental approaches on the analytical problem. copyright 1997 American Institute of Physics

  5. New method for mass spectrometric trace analysis of metals in biology and medicine

    International Nuclear Information System (INIS)

    Schulten, H.R.; Bahr, U.; Palavinskas, R.

    1984-01-01

    A first survey on the basic aspects and applications of a novel method for trace analyses of metals is given. The advantages of this methodology for analyses of trace metals which was developed by our group are: small sample amount, high sensitivity and selectivity, simple sample preparation for the measurement (no ashing) and reliability and precision of the results. The time consumption for one complete quantitative analysis lies below 30 min. The concentration of monoisotopic metals, as for example aluminium, cesium, manganese etc. is determined using a calibration curve. Using stable isotope dilution analysis quantification of metals with at least two stable isotopes further improved the precision of the results. If this technique is utilized, on one hand contamination of the environment by radioactive substances is avoided, on the other even the smallest changes in concentrations of trace metals are detected unambigeously. The accuracy of the resulting quantitative data has been confirmed test measurements with other analytical methods such as atomic absorption spectroscopy and thermal ionization mass spectrometry. Although there is no doubt that the greatest analytical capacity of field desorption mass spectrometry is in the field of high-molecular weight natural products, it has been possible in the last years to modify the method for qualitative and quantitative investigations of more than 60 metals. (orig./EF) [de

  6. Trace analysis of irradiated steel samples from hiroshima by laser ablation inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Helal, A.I.; Zahran, N.F.

    2000-01-01

    A double focusing (JEOL, PLASMAX2) and quadrupole (ELAN6000, Perkin Elmer) mass spectrometers were used for the quantitative analysis of trace elements in steel samples from Hiroshima. The quantification of the analytical results was carried out using steel 468 as a standard reference material. The relative sensitivity coefficients (RSC's) for most of the elements varied between 0.12 and 2.93. The effect of iron as a matrix and the non-spectroscopic interferences are studied. Comparison of the results obtained on two steel samples from Hiroshima with that obtained on steel 468 standard reference materials demonstrated that there is no significant difference between them. Therefore, it is possible to say that the irradiated steel samples from Hiroshima have nearly the same specifications of trace element content as those of the normal steel samples

  7. Trace analysis of plutonium in environmental samples by resonance ionization mass spectroscopy (RIMS)

    International Nuclear Information System (INIS)

    Erdmann, N.; Herrmann, G.; Huber, G.; Koehler, S.; Kratz, J.V.; Mansel, A.; Nunnemann, M.; Passler, G.; Trautmann, N.; Waldek, A.

    1997-01-01

    Trace amounts of plutonium in the environment can be detected by resonance ionization mass spectroscopy (RIMS). An atomic beam of plutonium is produced after its chemical separation and deposition on a filament. The atoms are ionized by a three-step excitation using pulsed dye-lasers. The ions are mass-selectively detected in a time-of-flight (TOF) mass spectrometer. With this setup a detection limit of 1·10 6 atoms of plutonium has been achieved. Furthermore, the isotopic composition can be determined. Different samples, including soil from the Chernobyl area, IAEA-certified sediments from the Mururoa Atoll and urine, have been investigated. copyright 1997 American Institute of Physics

  8. Identification of organically associated trace elements in wood and coal by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Richaud, R; Lazaro, M J; Lachas, H; Miller, B B; Herod, A A; Dugwell, D R; Kandiyoti, R

    2000-01-01

    1-Methyl-2-pyrrolidinone (NMP) was used to extract samples of wood (forest residue) and coal; the extracts were analysed by inductively coupled plasma mass spectrometry (ICP-MS) using two different sample preparation methods, in order to identify trace elements associated with the organic part of the samples. A sample of fly ash was similarly extracted and analysed in order to assess the behaviour of the mineral matter contained within the wood and coal samples. 32% of the biomass was extracted at the higher temperature and 12% at room temperature while only 12% of the coal was extracted at the higher temperature and 3% at room temperature. Less than 2% of the ash dissolved at the higher temperature. Size exclusion chromatograms of the extracts indicated the presence of significant amounts of large molecular mass materials (>1000 mu) in the biomass and coal extracts but not in the ash extract. Trace element analyses were carried out using ICP-MS on the acid digests prepared by 'wet ashing' and microwave extraction. Sixteen elements (As, Ba, Be, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, Pb, Sb, Se, V and Zn) were quantified, in the samples before extraction, in the extracts and in the residues. Concentrations of trace elements in the original biomass sample were lower than in the coal sample while the concentrations in the ash sample were the highest. The major trace elements in the NMP extracts were Ba, Cu, Mn and Zn from the forest residue; Ba, Cu, Mn, Pb and Zn from the coal; Cu and Zn from the ash. These elements are believed to be associated with the organic extracts from the forest residue and coal, and also from the ash. Be and Sb were not quantified in the extracts because they were present at too low concentrations; up to 40% of Mn was extracted from the biomass sample at 202 degrees C, while Se was totally extracted from the ash sample. For the forest residue, approximately 7% (at room temperature) and 45% (at 202 degrees C) of the total trace elements studied were

  9. Recent Developments in Trace, Ultratrace and Isotope Ratio Measurements in Inductively Coupled Plasma Mass Spectrometry

    International Nuclear Information System (INIS)

    Zahran, N. F.

    2004-01-01

    Inductively coupled plasma mass spectrometry (ICP-MS) and Laser Ablation (LA-ICP-MS) are recent techniques for trace, ultratrace and isotope ratio measurements. Main features of these techniques and their figure of merit and capabilities are discussed. An overview of ICP-MS instrument is presented in addition to its precision, accuracy and detection limits. Uses of ICP-MS in environmental monitoring in some cases for detection of some radio nuclides are presented. Two geological applications namely, zircon grains analysis and age dating of Rb-Sr method are presented. Zn elemental and isotopic analyses in blood and serum as a biological application is shown. (Author)

  10. Desorption electrospray ionization mass spectrometry for trace analysis of agrochemicals in food.

    Science.gov (United States)

    García-Reyes, Juan F; Jackson, Ayanna U; Molina-Díaz, Antonio; Cooks, R Graham

    2009-01-15

    Desorption electrospray ionization (DESI) is applied to the rapid, in situ, direct qualitative and quantitative (ultra)trace analysis of agrochemicals in foodstuffs. To evaluate the potential of DESI mass spectrometry (MS) in toxic residue testing in food, 16 representative multiclass agricultural chemicals (pesticides, insecticides, herbicides, and fungicides) were selected (namely, ametryn, amitraz, azoxystrobin, bitertanol, buprofezin, imazalil, imazalil metabolite, isofenphos-methyl, malathion, nitenpyram, prochloraz, spinosad, terbuthylazine, thiabendazole, and thiacloprid). The DESI-MS experiments were performed using 3 microL of solution spotted onto conventional smooth poly(tetrafluoroethylene) (PTFE) surfaces, with examination by MS and tandem mass spectrometry (MS/MS) using an ion trap mass spectrometer. Optimization of the spray solvent led to the use of acetonitrile/water (80:20) (v/v), with 1% formic acid. Most of the compounds tested showed remarkable sensitivity in the positive ion mode, approaching that attainable with conventional direct infusion electrospray mass spectrometry. To evaluate the potential of the proposed approach in real samples, different experiments were performed including the direct DESI-MS/MS analysis of fruit peels and also of fruit/vegetable extracts. The results proved that DESI allows the detection and confirmation of traces of agrochemicals in actual market-purchased samples. In addition, MS/MS confirmation of selected pesticides in spiked vegetable extracts was obtained at absolute levels as low as 1 pg for ametryn. Quantitation of imazalil residues was also undertaken using an isotopically labeled standard. The data obtained were in agreement with those from the liquid chromatography mass spectrometry (LC-MS) reference method, with relative standard deviation (RSD) values consistently below 15%. The results obtained demonstrate the sensitivity of DESI as they meet the stringent European Union pesticide regulation

  11. Diode laser based resonance ionization mass spectrometry for spectroscopy and trace analysis of uranium isotopes

    International Nuclear Information System (INIS)

    Hakimi, Amin

    2013-01-01

    In this doctoral thesis, the upgrade and optimization of a diode laser system for high-resolution resonance ionization mass spectrometry is described. A frequency-control system, based on a double-interferometric approach, allowing for absolute stabilization down to 1 MHz as well as frequency detunings of several GHz within a second for up to three lasers in parallel was optimized. This laser system was used for spectroscopic studies on uranium isotopes, yielding precise and unambiguous level energies, total angular momenta, hyperfine constants and isotope shifts. Furthermore, an efficient excitation scheme which can be operated with commercial diode lasers was developed. The performance of the complete laser mass spectrometer was optimized and characterized for the ultra-trace analysis of the uranium isotope 236 U, which serves as a neutron flux dosimeter and tracer for radioactive anthropogenic contaminations in the environment. Using synthetic samples, an isotope selectivity of ( 236 U)/( 238 U) = 4.5(1.5) . 10 -9 was demonstrated.

  12. Trace analysis of actinides in the environment using resonance ionization mass spectrometry

    International Nuclear Information System (INIS)

    Raeder, Sebastian

    2011-01-01

    In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10 4 -10 5 atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope 236 U a detection limit down to 10 -9 for the isotope ratio N ( 236 U)/N ( 238 U) could be determined.

  13. An industry-scale mass marking technique for tracing farmed fish escapees.

    Directory of Open Access Journals (Sweden)

    Fletcher Warren-Myers

    Full Text Available Farmed fish escape and enter the environment with subsequent effects on wild populations. Reducing escapes requires the ability to trace individuals back to the point of escape, so that escape causes can be identified and technical standards improved. Here, we tested if stable isotope otolith fingerprint marks delivered during routine vaccination could be an accurate, feasible and cost effective marking method, suitable for industrial-scale application. We tested seven stable isotopes, (134Ba, (135Ba, (136Ba, (137Ba, (86Sr, (87Sr and (26Mg, on farmed Atlantic salmon reared in freshwater, in experimental conditions designed to reflect commercial practice. Marking was 100% successful with individual Ba isotopes at concentrations as low as 0.001 µg. g-1 fish and for Sr isotopes at 1 µg. g-1 fish. Our results suggest that 63 unique fingerprint marks can be made at low cost using Ba (0.0002 - 0.02 $US per mark and Sr (0.46 - 0.82 $US per mark isotopes. Stable isotope fingerprinting during vaccination is feasible for commercial application if applied at a company level within the world's largest salmon producing nations. Introducing a mass marking scheme would enable tracing of escapees back to point of origin, which could drive greater compliance, better farm design and improved management practices to reduce escapes.

  14. Design of a compact permanent magnet Cyclotron Mass Spectrometer for the detection and measurement of trace isotopes

    International Nuclear Information System (INIS)

    Young, A.T.; Bertsche, K.J.; Clark, D.J.; Halbach, K.; Kunkel, W.B.; Leung, K.N.; Li, C.Y.

    1992-07-01

    A technique for the detection of trace amounts of rare isotopes, Cyclotron mass Spectrometry (CMS), is described. This technique uses the relationships between particle mass, charge, magnetic field strength and cyclotron orbital frequency to provide high mass resolution. The instrument also has high sensitivity and is capable of measuring isotopes with abundances of - 12 . Improvements now being implemented will lead to further increases in the sensitivity and enhance operating parameters such as cost, portability, and sample throughput

  15. Determination of trace quantities of uranium in rocks mass spectrometric isotope dilution technique

    International Nuclear Information System (INIS)

    Kakazu, Mauricio Hiromitu

    1980-01-01

    A detailed experimental investigation on the thermionic emission of uranium deposited on a single flat type rhenium filament has been carried out. The study was aimed at determining the influence of various forms of deposition on the emission sensitivity and thermal stability of U + , UO + and UO 2 + ions. Based on these investigations, a technique, involving an addition of a small quantity of colloidal suspension of graphite on top of the uranyl nitrate sample deposited, was chosen because of its higher, emission sensitivity for uranium metal ions. The experimental parameters of the technique were optimised and the technique was employed in the determination of trace quantities of uranium in rock samples using mass spectrometric isotope dilution method. For the mass spectrometric isotope dilution analysis National Bureau of Standards uranium isotopic standard NBS-U 970 was employed as a tracer, where as the mass discrimination effect in the uranium isotope analysis was corrected using the uranium isotopic standard NBS-U500. Uranium was determined in each of the seven granite samples from Wyoming, USA and two USGS standard rocks. The precision of the analysis was found to be ±1% . The uranium values obtained on the rock samples were compared with the analyses of other investigators. Influence of the sample splitting on the uranium analysis was discussed in the light of the analytical results obtained.(author)

  16. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    International Nuclear Information System (INIS)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H.

    2005-12-01

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here

  17. Separation Techniques for Uranium and Plutonium at Trace Levels for the Thermal Ionization Mass Spectrometric Determination

    Energy Technology Data Exchange (ETDEWEB)

    Suh, M. Y.; Han, S. H.; Kim, J. G.; Park, Y. J.; Kim, W. H

    2005-12-15

    This report describes the state of the art and the progress of the chemical separation and purification techniques required for the thermal ionization mass spectrometric determination of uranium and plutonium in environmental samples at trace or ultratrace levels. Various techniques, such as precipitation, solvent extraction, extraction chromatography, and ion exchange chromatography, for separation of uranium and plutonium were evaluated. Sample preparation methods and dissolution techniques for environmental samples were also discussed. Especially, both extraction chromatographic and anion exchange chromatographic procedures for uranium and plutonium in environmental samples, such as soil, sediment, plant, seawater, urine, and bone ash were reviewed in detail in order to propose some suitable methods for the separation and purification of uranium and plutonium from the safeguards environmental or swipe samples. A survey of the IAEA strengthened safeguards system, the clean room facility of IAEA's NWAL(Network of Analytical Laboratories), and the analytical techniques for safeguards environmental samples was also discussed here.

  18. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-456 Marine Sediment Samples

    International Nuclear Information System (INIS)

    2016-01-01

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioisotope analytical techniques to understand, monitor and protect the environment. In this context, the major impact of large coastal cities on marine ecosystems is an issue of prime concern for the IAEA and the IAEA Environment Laboratories. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. The IAEA Environment Laboratories has been assisting national laboratories and regional laboratory networks since the early 1970s through the provision of a reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Quality assurance, quality control and associated good laboratory practice are essential components of all marine environmental monitoring studies. Quality control procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess t h e reliability and comparability of measurement data. Data that are not based on adequate quality assurance and quality control can be erroneous, and their misuse can lead to poor environmental management decisions. A marine sediment sample with certified mass amount contents for aluminium, arsenic, cadmium chromium, cobalt, copper, iron, lead, mercury, methyl mercury, manganese, nickel, vanadium and zinc was recently produced by the IAEA Environment Laboratories. This publication presents the sample preparation methodology, including material homogeneity and the stability study, the selection of laboratories, the evaluation of results from the certification campaign, and the assignment of property values and their associated uncertainty. As a result, certified values for mass fractions and associated expanded uncertainty were

  19. Isotopic Tracing of Fuel Components in Particulate Emissions from Diesel Engines using Accelerator Mass Spectrometry (AMS)

    International Nuclear Information System (INIS)

    Buchholz, B A; Mueller, C J; Garbak, J.

    2001-01-01

    Accelerator mass spectrometry (AMS) is an isotope-ratio measurement technique developed in the late 1970s for tracing long-lived radioisotopes (e.g., 14 C half life = 5760 y). The technique counts individual nuclei rather than waiting for their radioactive decay, allowing measurement of more than 100 low-level 14 C samples per day (Vogel et al, 1995). The LLNL AMS system is shown in Fig.1. The contemporary quantity of 14 C in living things ( 14 C/C = 1.2 x 10 -12 or 110 fmol 14 C/ g C) is highly elevated compared to the quantity of 14 C in petroleum-derived products. This isotopic elevation is sufficient to trace the fate of bio-derived fuel components in the emissions of an engine without the use of radioactive materials. If synthesis of a fuel component from biologically-derived source material is not feasible, another approach is to purchase 14 C-labeled material (e.g., dibutyl maleate (DBM)) and dilute it with petroleum-derived material to yield a contemporary level of 14 C. In each case, the virtual absence of 14 C in petroleum based fuels gives a very low 14 C background that makes this approach to tracing fuel components practical. Regulatory pressure to significantly reduce the particulate emissions from diesel engines is driving research into understanding mechanisms of soot formation. If mechanisms are understood, then combustion modeling can be used to evaluate possible changes in fuel formulation and suggest possible fuel components that can improve combustion and reduce PM emissions. The combustion paradigm assumes that large molecules break down into small components and then build up again during soot formation. AMS allows us to label specific fuel components, including oxygenates, trace the carbon atoms, and test this combustion modeling paradigm. Volatile and non-volatile organic fractions (VOF, NVOF) in the PM can be further separated. The VOF of the PM can be oxidized with catalysts in the exhaust stream to further decrease PM. The effectiveness

  20. Mass-produced lonophore-based fluorescent microspheres for trace level determination of lead ions.

    Science.gov (United States)

    Telting-Diaz, Martin; Bakker, Eric

    2002-10-15

    The development and characterization of small, uniform, and mass-produced plasticized PVC-based sensing microspheres in view of rapid trace level analysis of lead ions is reported. Micrometer-sized particles obtained via an automated casting process were rendered selective for lead ions by doping them with highly selective components in a manner analogous to traditional optode sensing films. Single particles that contained the lipophilic ionophore N,N,N',N'-tetradodecyl-3-6-dioxaoctane-1-thio-8-oxodiamide (ETH 5493), the chromoionophore ETH 5418 together with a lipophilized indocarbocyanine derivative as internal reference dye (DiIC18), and lipophilic ion-exchanger sites sodium tetrakis[3,5-bistrifluoromethylphenyl]borate, yielded measurable lead responses at the low nanomolar level in pH buffered solutions. The detection limit for single particles was 3 x 10(-9) M at pH 5.7. The microspheres were fabricated via a reproducible formation of polymer droplets within a flowing aqueous phase followed by collection of spherical particles of approximately 13 microm in size. The particles were immobilized and assayed individually in a microflow cell via fluorescence microscopy. Selectivity patterns found were in agreement with those reported earlier for the lead-selective ligand ETH 5493, and all response functions were fully described by theory. In contrast to optode films that necessitated very long equilibration times and large sample volumes in diluted samples of analyte, particles exhibited extremely enhanced equilibrium response times. Thus, for lead sample concentrations at and above 5 x 10(-8) M, response times were approximately 3 min, whereas at the detection limit, complete equilibrium was recorded after just 15 min, with required sample volumes on the order of 1 mL This new class of microspheres appears to be suitable for rapid and sensitive ion detection at trace levels in environmental and biological applications.

  1. Certification of Trace Elements and Methylmercury Mass Fractions in Tuna Fish Flesh Homogenate IAEA-436A

    International Nuclear Information System (INIS)

    2017-01-01

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioactive isotope analytical techniques to understand, monitor and protect the marine environment. The major impact of large coastal cities on marine ecosystems is a primary concern for the IAEA. The Marine Environment Studies Laboratory, as a part of IAEA Environment Laboratories in Monaco, acts as the analytical support centre for Member State laboratories and is the pillar of the quality assurance programme for the determination of non-nuclear pollutants, trace elements and organic contaminants in the marine environment. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. Good laboratory practice and quality assurance and control are essential components of the analytical process for the production of data. Quality control procedures are commonly based on analyses of certified reference materials to assess reproducibility and measurement biases and uncertainties. Certified reference materials are key tools for quality assurance. They are used to validate analytical methods and to establish traceability to internationally agreed references. They are cornerstones for laboratory accreditation and the correct implementation of national and international regulations. In the development and validation of new methods, certified reference materials play a vital role in state of the art technologies where measurements are critical. The IAEA supports the development and production of environmental certified reference materials for monitoring laboratories in Member States. The reference material IAEA-436, characterized for trace elements and methylmercury mass fractions in tuna fish flesh homogenate, was produced by the IAEA in Monaco in 2006. This publication describes the production of certified reference material IAEA-436A, which is based on the

  2. Reference Materials for Trace Element Microanalysis of Carbonates by SIMS and other Mass Spectrometric Techniques

    Science.gov (United States)

    Layne, G. D.

    2009-12-01

    Today, many areas of geochemical research utilize microanalytical determinations of trace elements in carbonate minerals. In particular, there has been an explosion in the application of Secondary Ion Mass Spectrometry (SIMS) to studies of marine biomineralization. SIMS provides highly precise determinations of Mg and Sr at the concentration levels normally encountered in corals, mollusks or fish otoliths. It is also a highly effective means for determining a wide range of other trace elements at ppm levels (e.g., Na, Fe, Mn, Ba, REE, Pb, Th, and U) in a variety of naturally occurring calcite and aragonite matrices - and so is potentially valuable in studies of diagenesis, hydrothermal fluids and carbonatitic magmas. For SIMS, modest time per spot (often sputtered ion yields of most elements with the major element composition of the sample matrix, accuracy of SIMS depends intimately on matrix-matched solid reference materials. Despite its rapidly increasing use for trace element analyses of carbonates, there remains a dearth of certified reference materials suitable for calibrating SIMS. The pressed powders used by some analysts to calibrate LA-ICP-MS do not perform well for SIMS - they are not perfectly dense or homogeneous to the desired level at the micron scale of sampling. Further, they often prove incompatible with the sample high vacuum compatibility requirement for stable SIMS analysis (10-8 to 10-9 torr). Some naturally occurring calcite has apparent utility as a reference material. For example, equigranular calcite from some zones of carbonatite intrusions (sovites) and recrystallized calcites from highly metamorphosed metallic ore deposits. Most calcite marbles, though possibly appropriate as Sr standards, show substantial inhomogeneity in Mg, Mn and Ba. Some hydrothermal “Iceland Spar” calcite may prove useful as a reference for extremely low concentrations of Mg, Sr and Ba. The best carbonatitic calcites currently in use appear homogeneous to

  3. TRACING COLD H I GAS IN NEARBY, LOW-MASS GALAXIES

    International Nuclear Information System (INIS)

    Warren, Steven R.; Skillman, Evan D.; Stilp, Adrienne M.; Dalcanton, Julianne J.; Ott, Jürgen; Walter, Fabian; Petersen, Eric A.; Koribalski, Bärbel; West, Andrew A.

    2012-01-01

    We analyze line-of-sight atomic hydrogen (H I) line profiles of 31 nearby, low-mass galaxies selected from the Very Large Array—ACS Nearby Galaxy Survey Treasury (VLA-ANGST) and The H I Nearby Galaxy Survey (THINGS) to trace regions containing cold (T ∼ –1 . Our galaxy sample spans four orders of magnitude in total H I mass and nine magnitudes in M B . We fit single and multiple component functions to each spectrum to isolate the cold, neutral medium given by a low-dispersion ( –1 ) component of the spectrum. Most H I spectra are adequately fit by a single Gaussian with a dispersion of 8-12 km s –1 . Cold H I is found in 23 of 27 (∼85%) galaxies after a reduction of the sample size due to quality-control cuts. The cold H I contributes ∼20% of the total line-of-sight flux when found with warm H I. Spectra best fit by a single Gaussian, but dominated by cold H I emission (i.e., have velocity dispersions of –1 ), are found primarily beyond the optical radius of the host galaxy. The cold H I is typically found in localized regions and is generally not coincident with the very highest surface density peaks of the global H I distribution (which are usually areas of recent star formation). We find a lower limit for the mass fraction of cold-to-total H I gas of only a few percent in each galaxy.

  4. Determination of Trace Iron in Red Wine by Isotope Dilution Mass Spectrometry Using Multiple-Collector Inductively Coupled Plasma Mass Spectrometry

    International Nuclear Information System (INIS)

    Zhou Tao; Wang Jun; Lu Hai; Zhou Yuanjing; Li Haifeng

    2009-01-01

    This paper introduces determination of trace iron in red wine certified reference material by isotope dilution mass spectrometry (IDMS) method using a multiplecollector inductively coupled plasma mass spectrometry, equipped with a hexapole collision cell. The measurement procedure of iron isotopic abundance ratios was deeply researched. Reduced polyatomic ion interferences to iron isotopes ion by collision reaction using Ar and H 2 gas, high precise isotopic abundance ratios were achieved. Two relative measurement methods (ICP-MS and ICP-OES) were used to analyze trace iron in red wine. The results are compared with IDMS results, which indicate that they are accordant. The uncertainty analyses include each uncertainty factor in whole experiment and the uncertainty of used certified reference material and it shows that the procedure blank is not neglectable to detect limit and precision of the method. The establishment of IDMS method for analysis of trace iron in red wine supports the certification of certified reference materials. (authors)

  5. Certification of Trace Element Mass Fractions in IAEA-457 Marine Sediment Sample

    International Nuclear Information System (INIS)

    2013-01-01

    The primary goal of the IAEA Environment Laboratories in Monaco (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA and its Environment Laboratories. Given that marine pollution assessments of such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments, the NAEL has assisted national laboratories and regional laboratory networks through its Reference Products for Environment and Trade programme since the early 1970s. Quality assurance (QA), quality control (QC) and associated good laboratory practice are essential components of all marine environmental monitoring studies. QC procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess reliability and comparability of measurement data. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparisons, which compare and evaluate analytical performance and measurement capabilities of participating laboratories. Data that are not based on adequate QA/QC can be erroneous and their misuse can lead to incorrect environmental management decisions. A marine sediment sample with certified mass fractions for Ag, Al, As, Cd, Cr, Co, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sn, Sr, V and Zn was recently produced by the NAEL in the frame of a project between the IAEA and the Korea Institute of Ocean Science and Technology. This report describes the sample preparation methodology, the material homogeneity and stability study, the selection of laboratories, the evaluation of results from the certification campaign and the assignment of property values and their associated uncertainty. As a result, reference values for mass fractions and associated expanded

  6. Trace level detection of explosives in solution using leidenfrost phenomenon assisted thermal desorption ambient mass spectrometry.

    Science.gov (United States)

    Saha, Subhrakanti; Mandal, Mridul Kanti; Chen, Lee Chuin; Ninomiya, Satoshi; Shida, Yasuo; Hiraoka, Kenzo

    2013-01-01

    The present paper demonstrates the detection of explosives in solution using thermal desorption technique at a temperature higher than Leidenfrost temperature of the solvent in combination with low temperature plasma (LTP) ionization. Leidenfrost temperature of a solvent is the temperature above which the solvent droplet starts levitation instead of splashing when placed on a hot metallic surface. During this desorption process, slow and gentle solvent evaporation takes place, which leads to the pre-concentration of less-volatile explosive molecules in the droplet and the explosive molecules are released at the last moment of droplet evaporation. The limits of detection for explosives studied by using this thermal desorption LTP ionization method varied in a range of 1 to 10 parts per billion (ppb) using a droplet volume of 20 μL (absolute sample amount 90-630 fmol). As LTP ionization method was applied and ion-molecule reactions took place in ambient atmosphere, various ion-molecule adduct species like [M+NO2](-), [M+NO3](-), [M+HCO3](-), [M+HCO4](-) were generated together with [M-H](-) peak. Each peak was unambiguously identified using 'Exactive Orbitrap' mass spectrometer in negative ionization mode within 3 ppm deviation compared to its exact mass. This newly developed technique was successfully applied to detect four explosives contained in the pond water and soil sample with minor sample pre-treatment and the explosives were detected with ppb levels. The present method is simple, rapid and can detect trace levels of explosives with high specificity from solutions.

  7. Trace Analysis of Irradiated Granite Samples from Hiroshima by Laser Ablation Inductively Coupled Plasma Mass Spectrometry

    International Nuclear Information System (INIS)

    Amr, M.A.; Helal, N.F.; Zahran, N.F.; Becker, J.S.; Pickhardt, C.; Dietze, H.J.

    1999-01-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is widely accepted as a rapid and sensitive technique for trace elemental analysis of solid materials and for local analysis of inhomogeneous materials (such as geological samples). Due to its direct solid sample analysis capability, LA-ICP-MS (using a quadrupole based ICP-MS and at the Research Center Juelich developed laser ablation system: Nd-YAG-laser, 226 nm, 10 Hz and 5 ns) is applied for the analysis of geological (granite) samples from Hiroshima. In order to prepare homogeneous targets, these samples were melted together with a lithium-borate mixture in a muffle furnace at 1050 degree c. Furthermore, for investigating of matrix effects the powder of these samples is mixed with graphite and pressed as targets for laser ablation. The quantification of the analysis results was carried out using granite (GM) as standard reference material. The relative sensitivity coefficients (RSCs) for most elements, which were determined for correction of the measured values, varied between 0.3 and 3

  8. Development of a mass spectrometry immunoassay for unambiguous detection of egg allergen traces in wines.

    Science.gov (United States)

    Pilolli, Rosa; Chaudhari, Ravindra; Palmisano, Francesco; Monaci, Linda

    2017-02-01

    A mass spectrometry immunoassay (MSIA) specifically designed for the detection of egg allergens in wines is described. MSIA is based on an immunoaffinity enrichment procedure combined with targeted MS/MS detection of selected egg peptide markers. Polyclonal antibodies raised against native ovalbumin, chosen as the target protein tracing for egg powder, were immobilized onto low backpressure monolithic MSIA customized disposable tips. Ovalbumin-free wine samples were fortified with standard protein at different concentrations in the low microgram-per-milliliter range. A simple protocol was devised consisting of a 1:4 dilution of the wine sample with a basic solution for pH adjustment, followed by a semi-automated purification/enrichment step on MSIA customized disposable tips fitted on a multichannel electronic pipette. Among the main figures of merit, LOD and LOQ values as low as 0.01 and 0.03 μg/mL, respectively, and within-day precision of 18% should be noticed. Noteworthy, the developed assay outperformed current MS-based methods for the detection of allergenic protein in wine matrices, thanks to the immunoaffinity enrichment. In addition, compared to other immunoassays, the present approach boasts the unquestionable advantage of providing an unambiguous identification of the target protein by simultaneous detection of three unique peptide markers each giving three specific MS/MS transitions.

  9. Mass spectrometric methods for studying nutrient mineral and trace element absorption and metabolism in humans using stable isotopes: a review

    International Nuclear Information System (INIS)

    Crews, H.M.; Eagles, J.; Mellon, F.A.; Luten, J.B.; McGaw, B.A.

    1994-01-01

    Mass spectrometric methods for determining stable isotopes of nutrient minerals and trace elements in human metabolic studies are described and discussed. The advantages and disadvantages of the techniques of electron ionization, fast atom bombardment, thermal ionization, and inductively coupled plasma and gas chromatography mass spectrometry are evaluated with reference to their accuracy, precision, sensitivity, and convenience, and the demands of human nutrition research. Examples of specific applications are described and the significance of current developments in mass spectrometry are discussed with reference to present and probable future research needs. (Author)

  10. Biomonitor-Reflection of Large-Distance Air Mass Transported Trace Elements

    NARCIS (Netherlands)

    Henriques Vieira, B.J.

    2017-01-01

    The present thesis’ topic is the biomonitoring of atmospheric trace elements with attention focused on the long-range transported trace elements. The aim was to provide improved understanding of aerosol characteristics under the atmospheric transport dynamics of Central North Atlantic at different

  11. Total and species-specific quantitative analyses of trace elements in sediment by isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Inagaki, Kazumi; Takatsu, Akiko; Yarita, Takashi; Okamoto, Kensaku; Chiba, Koichi

    2009-01-01

    Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is one of the reliable methods for total and species-specific quantitative analysis of trace elements. However, several technical problems (e.g. spectral interference caused from sample constituents) should be overcome to obtain reliable analytical results when environmental samples are analyzed by ID-ICP-MS. In our laboratory, various methods based on ID-ICP-MS have been investigated for reliable quantitative analyses of trace elements in environmental samples. In this paper, coprecipitate separation/ID-ICP-MS for the determination of trace elements in sediment, cation exchange disk filtration/ID-ICP-MS for the determination of selenium in sediment, species-specific ID-ICP-MS using 118 Sn/labeled organotin compounds for the determination of butyltins and phenyltins, and the application of the ID-ICP-MS methods to the certification of sediment reference materials are described. (author)

  12. TRACING THE LOWEST PROPELLER LINE IN MAGELLANIC HIGH-MASS X-RAY BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Christodoulou, Dimitris M.; Laycock, Silas G. T.; Yang, Jun; Fingerman, Samuel, E-mail: dimitris_christodoulou@uml.edu, E-mail: silas_laycock@uml.edu, E-mail: jun_yang@uml.edu, E-mail: fingerman.samuel@gmail.com [Lowell Center for Space Science and Technology, 600 Suffolk Street, Lowell, MA 01854 (United States)

    2016-09-20

    We have combined the published observations of high-mass X-ray binary (HMXB) pulsars in the Magellanic Clouds with a new processing of the complete archival data sets from the XMM-Newton and Chandra observatories in an attempt to trace the lowest propeller line below which accretion to polar caps is inhibited by the centrifugal force and the pulsations from the most weakly magnetized pulsars cease. Previously published data reveal that some of the faster-spinning pulsars with spin periods of P {sub S} < 12 s, detected at relatively low X-ray luminosities L {sub X} , appear to define such a line in the P {sub S} – L {sub X} diagram, characterized by a magnetic moment of μ = 3 × 10{sup 29} G cm{sup 3}. This value implies the presence of surface magnetic fields of B ≥ 3 × 10{sup 11} G in the compact objects of this class. Only a few quiescent HMXBs are found below the propeller line: LXP4.40 and SXP4.78, for which XMM-Newton and Chandra null detections respectively placed firm upper limits on their X-ray fluxes in deep quiescence; and A0538-66, for which many sub-Eddington detections have never measured any pulsations. On the other hand, the data from the XMM-Newton and Chandra archives show clearly that, during routine observation cycles, several sources have been detected below the propeller line in extremely faint, nonpulsating states that can be understood as the result of weak magnetospheric emission when accretion to the poles is centrifugally stalled or severely diminished. We also pay attention to the anomalous X-ray pulsar CXOU J010043.1-721134 that was reported in HMXB surveys. Its pulsations and locations near and above the propeller line indicate that this pulsar could be accreting from a fossil disk.

  13. Quantitative Detection of Trace Malachite Green in Aquiculture Water Samples by Extractive Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Fang, Xiaowei; Yang, Shuiping; Chingin, Konstantin; Zhu, Liang; Zhang, Xinglei; Zhou, Zhiquan; Zhao, Zhanfeng

    2016-08-11

    Exposure to malachite green (MG) may pose great health risks to humans; thus, it is of prime importance to develop fast and robust methods to quantitatively screen the presence of malachite green in water. Herein the application of extractive electrospray ionization mass spectrometry (EESI-MS) has been extended to the trace detection of MG within lake water and aquiculture water, due to the intensive use of MG as a biocide in fisheries. This method has the advantage of obviating offline liquid-liquid extraction or tedious matrix separation prior to the measurement of malachite green in native aqueous medium. The experimental results indicate that the extrapolated detection limit for MG was ~3.8 μg·L(-1) (S/N = 3) in lake water samples and ~0.5 μg·L(-1) in ultrapure water under optimized experimental conditions. The signal intensity of MG showed good linearity over the concentration range of 10-1000 μg·L(-1). Measurement of practical water samples fortified with MG at 0.01, 0.1 and 1.0 mg·L(-1) gave a good validation of the established calibration curve. The average recoveries and relative standard deviation (RSD) of malachite green in lake water and Carassius carassius fish farm effluent water were 115% (6.64% RSD), 85.4% (9.17% RSD) and 96.0% (7.44% RSD), respectively. Overall, the established EESI-MS/MS method has been demonstrated suitable for sensitive and rapid (malachite green in various aqueous media, indicating its potential for online real-time monitoring of real life samples.

  14. Analysis of Trace Elements in Rat Bronchoalveolar Lavage Fluid by Inductively Coupled Plasma Mass Spectrometry.

    Science.gov (United States)

    Qamar, Wajhul; Al-Ghadeer, Abdul Rahman; Ali, Raisuddin; Abuelizz, Hatem A

    2017-08-01

    The main objective was to determine the elemental profile of the lung lining fluid of rats which are used as model animals in various experiments. Lung lining fluid elemental constitution obtained after bronchoalveolar lavage fluid (BALF) was analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to determine the biological trace elements along with calcium and magnesium. BALF was collected from healthy rats using a tracheal cannula. However, cells in BALF were counted to monitor any underlying inflammatory lung condition. Cell free BALF samples were processed and analyzed for the elements including magnesium (Mg), calcium (Ca), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), selenium (Se), bromine (Br), and iodine (I). In view of this, calcium concentration was the highest (6318.08 ± 3094.3 μg/L) and copper concentration was the lowest (0.89 ± 0.21 μg/L). The detected elements, from high to low concentration, include Ca > Mg > Fe > Br > I > Cr > Ni > Zn > Mn > Se > Cu. Pearson's correlation analysis revealed no significant correlation between cell count and concentration of any of the element detected in BALF. Correlation analysis also revealed significant positive correlation among Fe, I, Cr, Ni, and Mn. Ca was found to be correlated negatively with Cu and positively with Se. Br and Mg found to be positively correlated with each other. Zn remained the only element that was not found to be correlated with any of the elements in the rat BALF.

  15. Certification of Trace Element Mass Fractions in IAEA-458 Marine Sediment Sample

    International Nuclear Information System (INIS)

    2013-01-01

    The primary goal of the IAEA Environment Laboratories (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA and its Environment Laboratories. Given that marine pollution assessments of such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments, the NAEL has assisted national laboratories and regional laboratory networks through its Reference Products for Environment and Trade programme since the early 1970s. Quality assurance (QA), quality control (QC) and associated good laboratory practice are essential components of all marine environmental monitoring studies. QC procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess reliability and comparability of measurement data. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparisons, which compare and evaluate the analytical performance and measurement capabilities of participating laboratories. Data that are not based on adequate QA/QC can be erroneous, and their misuse can lead to incorrect environmental management decisions. This report describes the sample preparation methodology, material homogeneity and stability study, selection of laboratories, evaluation of results from the certification campaign and assignment of property values and their associated uncertainty. As a result, reference values for mass fractions and associated expanded uncertainty for 16 trace elements (Al, As, Cd, Cr, Co, Cu, Fe, Hg, Li, Mn, Ni, Pb, Sr, Sn, V and Zn) in marine sediment were established

  16. NO TRACE LEFT BEHIND: STEREO OBSERVATION OF A CORONAL MASS EJECTION WITHOUT LOW CORONAL SIGNATURES

    International Nuclear Information System (INIS)

    Robbrecht, Eva; Patsourakos, Spiros; Vourlidas, Angelos

    2009-01-01

    The availability of high-quality synoptic observations of the extreme-ultraviolet (EUV) and visible corona during the SOHO mission has advanced our understanding of the low corona manifestations of coronal mass ejections (CMEs). The EUV imager/white light coronagraph connection has been proven so powerful, it is routinely assumed that if no EUV signatures are present when a CME is observed by a coronagraph, then the event must originate behind the visible limb. This assumption carries strong implications for space weather forecasting but has not been put to the test. This paper presents the first detailed analysis of a frontside, large-scale CME that has no obvious counterparts in the low corona as observed in EUV and Hα wavelengths. The event was observed by the SECCHI instruments onboard the STEREO mission. The COR2A coronagraph observed a slow flux-rope-type CME, while an extremely faint partial halo was observed in COR2B. The event evolved very slowly and is typical of the streamer-blowout CME class. EUVI A 171 A images show a concave feature above the east limb, relatively stable for about two days before the eruption, when it rises into the coronagraphic fields and develops into the core of the CME. None of the typical low corona signatures of a CME (flaring, EUV dimming, filament eruption, waves) were observed in the EUVI B images, which we attribute to the unusually large height from which the flux rope lifted off. This interpretation is supported by the CME mass measurements and estimates of the expected EUV dimming intensity. Only thanks to the availability of the two viewpoints we were able to identify the likely source region. The event originated along a neutral line over the quiet-Sun. No active regions were present anywhere on the visible (from STEREO B) face of the disk. Leaving no trace behind on the solar disk, this observation shows unambiguously that a CME eruption does not need to have clear on-disk signatures. Also it sheds light on the

  17. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-461 Clam (Gafrarium tumidum) Sample

    International Nuclear Information System (INIS)

    2016-01-01

    The primary goal of the IAEA Environment Laboratories is to assist Member States in the use of both stable and radioisotope analytical techniques to understand, monitor and protect the environment. In this context, the major impact exerted by large coastal cities on marine ecosystems is an issue of primary concern for the IAEA and the IAEA Environment Laboratories. The marine pollution assessments required to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. The IAEA Environment Laboratories has been assisting national laboratories and regional laboratory networks since the early 1970s through the provision of reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Quality assurance, quality control and associated good laboratory practice are essential components of all marine environmental monitoring studies. Quality control procedures are commonly based on the analysis of certified reference materials and reference samples in order to validate analytical methods used in monitoring studies and to assess the reliability and comparability of measurement data. Data that are not based on adequate quality assurance and quality control can be erroneous, and their misuse can lead to poor environmental management decisions. This publication describes the production of the IAEA-461 certified reference material, which was produced following ISO Guide 34:2009, General Requirements for the Competence of Reference Material Producers. A sample of approximately 60 kg of clams (Gafrarium tumidum) was collected in Noumea, New Caledonia, and processed at the IAEA Environment Laboratories to produce a certified reference material of marine biota. The sample contained certified mass fractions for arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, mercury, methyl mercury, manganese, nickel, selenium, vanadium and zinc. The produced vials

  18. Mass-spectrometric analysis of trace oxygen in carbon dioxide; Analyse de traces d'oxygene dans le gaz carbonique par spectrometrie de masse

    Energy Technology Data Exchange (ETDEWEB)

    Nief, G; Severin, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    The mass spectrum of pure CO{sub 2} contains a peak of weight 32 whose relationship to peak at 44 varies greatly depending on the previous history of the source of ions and even during the course of an analysis. The fact that this peak is more or less proportional to the pressure and that its appearance potential is the same as that of oxygen leads us to suppose that it is produced from oxygen formed by dissociation of the carbon dioxide on the tungsten filament. A prior treatment of the ion source with acetylene reduces the ratio 32/44 to a value of about 15.10{sup -5}. This same treatment also stabilises the spectrometer's sensitivity to oxygen. Two lines of introduction enable pure carbon dioxide, the specimen to be estimated and a reference mixture of known oxygen content to be sent into the mass spectrometer in quick succession. Oxygen in the carbon dioxide in amounts ranging between 0 and 500 p.p.m. can thus be determined to an accuracy of {+-} 5 p.p.m., the analysis taking 30 minutes. (author) [French] Le spectre de masse de CO{sub 2} pur contient un pic de masse 32 dont le rapport au pic 44 varie enormement suivant l'histoire anterieure de la source d'ions et meme au cours d'une analyse. Le fait que ce pic soit grossierement proportionnel a la pression et que son potentiel d'apparition soit le meme que celui de l'oxygene permet de supposer qu'il est engendre a partir de l'oxygene produit par dissociation du gaz carbonique sur le filament de tungstene. Un conditionnement prealable de la source d'ions avec de l'acetylene reduit le rapport 32/44 a une valeur d'environ 15.10{sup -5}. Ce meme traitement stabilise egalement la sensibilite du spectrometre vis-a-vis de l'oxygene. Une double ligne d'introduction de gaz permet d'envoyer en successions rapides dans le spectrometre de masse le gaz carbonique pur, l'echantillon a doser et un melange de reference de teneur en oxygene connue. On arrive ainsi a doser l'oxygene dans le gaz carbonique dans la gamme de 0 a

  19. Time resolved investigations on biogenic trace gases exchanges using proton-transfer-reaction mass spectrometry

    International Nuclear Information System (INIS)

    Karl, T.

    2000-02-01

    1999/2000 completed this thesis and were used to evaluate and confirm the previously described investigations. The outcome of these measurements are summarized in the following abstracts submitted to the EGS 2000 (Nizza, France) and SASP 2000 (Folgaria, Italy) conferences: 1. Volatile organic compounds (VOCs) in the free troposphere at the Sonnblick Observatory, Austria (3106 m a.s.l.) were measured during November 1999. VOCs in the 0.5 to 5 ppbv range included hexenals, hexanal, methylbutanals, and especially 1-penten-3-ol; even higher levels of acetaldehyde (5 to 26 ppbv) were measured. The common origins of these compounds are proposed to be leaves which are senescing and/or subjected to freeze-thaw damage; this is inferred from laboratory investigations and by tracing air mass trajectories to urban or rural sites. This work suggests the Earth's deciduous forests may release large amounts of reactive VOCs during the autumn. 2. A PTR-MS-GC system was set up to identify lipoxygenase peroxidation products during freezing induced wounding, senescing and general wounding in various plants. In all laboratory experiments we observed substantial production of 1-penten-3-ol, cis-2-penten-1-ol, hexenal and hexenol isomers, all reactive oxygenates that contribute to tropospheric chemistry. Special attention is drawn to the production of pentenols, compounds which have not been reported to be present in large amounts in the atmosphere. PTR-MS online measurements on the Sonnblick observatory in the Austrian Alps (3106 m) show that even in the free troposphere substantial amounts of pentenols can be present as the result of ongoing freezing and senescing in deciduous plants. We also observed high mixing ratios of hexenals, acetaldehyde, methanol, 2-methylbutanal, 3-methylbutanal, EVK and acetone, all coming from local vegetation near the Sonnblick. 3. It was possible to estimate OH-radical concentrations on the 27 th November 1999 at the Sonnblick Observatory. During daytime the

  20. Quantitative sampling and analysis of trace elements in atmospheric aerosols: impactor characterization and Synchrotron-XRF mass calibration

    Directory of Open Access Journals (Sweden)

    A. Richard

    2010-10-01

    Full Text Available Identification of trace elements in ambient air can add substantial information to pollution source apportionment studies, although they do not contribute significantly to emissions in terms of mass. A method for quantitative size and time-resolved trace element evaluation in ambient aerosols with a rotating drum impactor and synchrotron radiation based X-ray fluorescence is presented. The impactor collection efficiency curves and size segregation characteristics were investigated in an experiment with oil and salt particles. Cutoff diameters were determined through the ratio of size distributions measured with two particle sizers. Furthermore, an external calibration technique to empirically link fluorescence intensities to ambient concentrations was developed. Solutions of elemental standards were applied with an ink-jet printer on thin films and area concentrations were subsequently evaluated with external wet chemical methods. These customized and reusable reference standards enable quantification of different data sets analyzed under varying experimental conditions.

  1. Application of ICP-MS to a trace elements mass balance study in a power plant

    NARCIS (Netherlands)

    Bettinelli, M.; Spezia, S.; Fiore, A.; Pastorelli, N.; Terni, C.; Holland, G.; Tanner, S.D.

    2001-01-01

    The distributions of seven trace elements in a power plant are detd. in 3 fuels (Orimulsion, coal, and fuel oil) and output flows, i.e., ash, wastewater, gypsum, and emulsions by using ICP-MS. The power plant is equipped with sulfur oxide and nitrogen oxide removal facilities. [on SciFinder (R)

  2. Real-time monitoring of trace-level VOCs by an ultrasensitive compact lamp-based VUV photoionization mass spectrometer

    Science.gov (United States)

    Sun, W. Q.; Shu, J. N.; Zhang, P.; Li, Z.; Li, N. N.; Liang, M.; Yang, B.

    2015-06-01

    In this study, we report on the development of a compact lamp-based vacuum ultraviolet (VUV) photoionization mass spectrometer (PIMS; hereafter referred to as VUV-PIMS) in our laboratory; it is composed of a radio frequency-powered VUV lamp, a VUV photoionizer, an ion-immigration region, and a reflection time-of-flight mass spectrometer. By utilizing the novel photoionizer consisting of a photoionization cavity and a VUV light baffle, extremely low background noise was obtained. An ultrasensitive detection limit (2σ) of 3 pptv was achieved for benzene after an acquisition time of 10 s. To examine its potential for application in real-time sample monitoring, the developed VUV-PIMS was employed for the continuous measurement of urban air for six days in Beijing, China. Strong signals of trace-level volatile organic compounds such as benzene and its alkylated derivatives were observed in the mass spectra. These initial experimental results reveal that the instrument can be used for the online monitoring of trace-level species in the atmosphere.

  3. Effects of statistical distribution of joint trace length on the stability of tunnel excavated in jointed rock mass

    Directory of Open Access Journals (Sweden)

    Kayvan Ghorbani

    2015-12-01

    Full Text Available The rock masses in a construction site of underground cavern are generally not continuous, due to the presence of discontinuities, such as bedding, joints, faults, and fractures. The performance of an underground cavern is principally ruled by the mechanical behaviors of the discontinuities in the vicinity of the cavern. During underground excavation, many surrounding rock failures have close relationship with joints. The stability study on tunnel in jointed rock mass is of importance to rock engineering, especially tunneling and underground space development. In this study, using the probability density distribution functions of negative exponential, log-normal and normal, we investigated the effect of joint trace length on the stability parameters such as stress and displacement of tunnel constructed in rock mass using UDEC (Universal Distinct Element Code. It was obtained that normal distribution function of joint trace length is more critical on the stability of tunnel, and exponential distribution function has less effect on the tunnel stability compared to the two other distribution functions.

  4. Forensic traces of propellants on the fingerprints in mass spectra s; Forenzne stopy strelivin na odtlackoch prstov v hmotnostnych spektrach

    Energy Technology Data Exchange (ETDEWEB)

    Slusna, L; Stupavska, M; Velic, D [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Katedra fyzikalnej a teoretickej chemie, 84215 Bratislava (Slovakia)

    2012-04-25

    Forensic science deals with exploring and discovering of the traces as well as with criminal investigation using physical-chemical methods. Part of forensic science, which deals with the examination of fingerprints and identifying the persons using them, is called the despotically. This method deals with the morphology of the fingerprint. This work uses the method of secondary ion mass spectrometry for the chemical characterization of the fingerprint. The aim of the experiment was to identify the presence of chemical propellants on the fingerprint and to demonstrate clearly the presence of gunpowder. (authors)

  5. Direct trace analysis of metals and alloys in a quadrupole ion-trap mass spectrometer

    CERN Document Server

    Song, K S; Yang, M; Cha, H K; Lee, J M; Lee, G H

    1999-01-01

    An ion-trap mass spectrometer adopting a quadrupole ion-trap and laser ablation/ionization method was constructed. The developed system was tested for composition analysis of some metals (Cu, stainless), and alloys (hastalloy C, mumetal) by mass spectrometry. Samples were analyzed by using laser ablation from a sample probe tip followed by a mass analysis with the quadrupole ion-trap. The quadrupole ion-trap was modified to enable laser ablation by a XeCl excimer laser pulse that passed radially through the ring electrode. A mass scan of the produced ions was performed in the mass selective instability mode wherein trapped ions were successively detected by increasing the rf voltage through the ring electrode. Factors affecting the mass resolution, such as pressure of buffer gas and ablation laser power, are discussed.

  6. Multi-elemental determination of trace elements in deep seawater by inductively coupled plasma mass spectrometry with resin preconcentration

    International Nuclear Information System (INIS)

    Sumida, Takashi; Nakazato, Tetsuya; Tao, Hiroaki

    2003-01-01

    A miniaturized column (ca. 3 mm i.d., 40 mm length), packed with a chelating resin (0.2 g) with iminodiacetic acid groups (Muromac A-1), was tested for the preconcentration of trace elements in seawater. After preconcentration, the column was washed with ammonium acetate buffer (pH 5.5) and water to remove the major elements, such as Ca and Mg, and was then eluted with 4 ml of 2 mol l -1 nitric acid. Twenty-six trace elements were determined by inductively coupled plasma mass spectrometry and inductively coupled plasma emission spectrometry. The necessary volume of the seawater sample was only 200 ml. The recoveries for most of the elements tested were over 90%, although those for Al, V and Th were around 70%. The trueness and precision were evaluated by analyzing a standard reference material of seawater (NASS-4, NRC Canada). The observed values obtained with the present method showed good agreement with the certified values. The present method was also applied to deep seawater samples collected at Muroto, Japan. A difference in the rare earth element pattern, especially the Ce anomaly, between the deep seawater sample and the surface seawater sample was observed, as well as the differences of the concentrations of many trace elements. (author)

  7. Certification for Trace Elements and Methyl Mercury Mass Fractions in IAEA-452 Scallop (Pecten maximus) Sample

    International Nuclear Information System (INIS)

    2013-01-01

    The primary goal of the IAEA Environment Laboratories (NAEL) is to help Member States understand, monitor and protect the marine environment. The major impact exerted by large coastal cities on marine ecosystems is therefore of great concern to the IAEA, particularly to its Environment Laboratories. The marine pollution assessments needed to understand such impacts depend on accurate knowledge of contaminant concentrations in various environmental compartments. Two fundamental requirements to ensure the reliability of analytical results are quality control (QC) and quality assurance (QA). Since the early 1970s, NAEL has been assisting national laboratories and regional laboratory networks through its reference material programme for the analysis of radionuclides, trace elements and organic compounds in marine samples. Relevant activities include global interlaboratory comparison exercises and regional proficiency tests, the production of marine reference materials, and the development of reference methods for analysis of trace elements and organic pollutants in marine samples. QA, QC and associated good laboratory practice should be essential components of all marine environmental monitoring. QC procedures are commonly based on the analysis of reference materials to assess reproducibility and measurement bias. QA can be realized by participation in externally organized laboratory performance studies, also known as interlaboratory comparison exercises, which compare and evaluate the analytical performance and measurement capabilities of participating laboratories. The need for good QA/QC in the chemical analysis of marine environmental samples is widely recognized and has been tested in a number of international QA exercises. Such diligence also needs to be applied to other components of the monitoring exercise, since these may represent a greater source of error in many instances. Data that are not based on adequate QA/QC can be erroneous, and their misuse can lead

  8. Bioimaging mass spectrometry of trace elements – recent advance and applications of LA-ICP-MS: A review

    Energy Technology Data Exchange (ETDEWEB)

    Becker, J.Sabine, E-mail: s.becker@fz-juelich.de [Central Institute for Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Jülich, Jülich D-52425 (Germany); Matusch, Andreas, E-mail: a.matusch@fz-juelich.de [Institute for Neuroscience and Medicine (INM-2), Forschungszentrum Jülich, Jülich D-52425 (Germany); Wu, Bei, E-mail: b.wu@fz-juelich.de [Central Institute for Engineering, Electronics and Analytics (ZEA-3), Forschungszentrum Jülich, Jülich D-52425 (Germany)

    2014-07-04

    Highlights: • Bioimaging LA-ICP-MS is established for trace metals within biomedical specimens. • Trace metal imaging allows to study brain function and neurodegenerative diseases. • Laser microdissection ICP-MS was applied to mouse brain hippocampus and wheat root. - Abstract: Bioimaging using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) offers the capability to quantify trace elements and isotopes within tissue sections with a spatial resolution ranging about 10–100 μm. Distribution analysis adds to clarifying basic questions of biomedical research and enables bioaccumulation and bioavailability studies for ecological and toxicological risk assessment in humans, animals and plants. Major application fields of mass spectrometry imaging (MSI) and metallomics have been in brain and cancer research, animal model validation, drug development and plant science. Here we give an overview of latest achievements in methods and applications. Recent improvements in ablation systems, operation and cell design enabled progressively better spatial resolutions down to 1 μm. Meanwhile, a body of research has accumulated covering basic principles of the element architecture in animals and plants that could consistently be reproduced by several laboratories such as the distribution of Fe, Cu, Zn in rodent brain. Several studies investigated the distribution and delivery of metallo-drugs in animals. Hyper-accumulating plants and pollution indicator organisms have been the key topics in environmental science. Increasingly, larger series of samples are analyzed, may it be in the frame of comparisons between intervention and control groups, of time kinetics or of three-dimensional atlas approaches.

  9. Trace analysis of U, Th and other heavy metals in high purity aluminium with isotope dilution mass spectrometry

    International Nuclear Information System (INIS)

    Beer, B.; Heumann, K.G.

    1992-01-01

    A method for the determination of very low concentrations of U, Th, Fe, Zn, Tl, Cd, Cu and Ag in high purity aluminium with isotope dilution mass spectrometry (IDMS) is developed using a compact and cost-efficient thermal ionization quadrupole mass spectrometer. The detection limits obtained are (in ng/g):U=0.018, Th=0.06, Fe=82, Zn=86, Tl=0.2, Cd=4, Cu=1, Ag=2.6. By this method it is possible to determine the α-emitters U and Th in aluminium down to the sub-ng/g level with good precision of 0.4-10% and 0.5-5%, respectively. The results should also be accurate because IDMS is a reliable analytical method. The dissolution of aluminium is carried out by aqua regia followed by the trace/matrix separation and the isolation of the trace elements by anion exchange chromatography (U, Th, Zn, Tl, Cd), electrodeposition (Cu, Ag) and extraction (Fe). Different aluminium samples are analysed by IDMS and the results are compared with those of other methods. (orig.)

  10. Investigations on the direct introduction of cigarette smoke for trace elements analysis by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Chang, Michael J.; Naworal, John D.; Walker, Kathleen; Connell, Chris T.

    2003-01-01

    Direct introduction of mainstream cigarette smoke into an inductively coupled plasma mass spectrometry (ICP-MS) has been investigated with respect to its feasibility for on-line analysis of trace elements. An automated apparatus was designed and built interfacing a smoking machine with an ICP-MS for smoke generation, collection, injection and analysis. Major and minor elements present in the particulate phase and the gas phase of mainstream cigarette smoke of 2R4F reference cigarettes have been qualitatively identified by examination of their full mass spectra. This method provides a rapid-screening analysis of the transfer of trace elements into mainstream smoke during cigarette combustion. A full suite of elements present in the whole cigarette smoke has been identified, including As, B, Ba, Br, Cd, Cl, Cs, Cu, Hg, I, K, Li, Mn, Na, Pb, Rb, Sb, Sn, Tl and Zn. Of these elements, the major portions of B, Ba, Cs, Cu, K, Li, Mn, Na, Pb, Rb, Sn, Tl and Zn are present in the particulate phase, whereas the major portion of Hg is present in the gas phase. As, Br, Cd, Cl, I and Sb exist in a distribution between the gas phase and the particulate phase. Depending on the element, the precision of measurement ranges from 5 to 25% in terms of relative standard deviation of peak height and peak area, based on the fourth puff of 2R4F mainstream cigarette smoke analyzed in five smoking replicates

  11. Development of accurate mass spectrometric routine and reference methods for the determination of trace amounts of iridium and rhodium in photographic emulsionsf

    NARCIS (Netherlands)

    Krystek, Petra; Heumann, Klaus G.

    1999-01-01

    For the determination of trace amounts of iridium and rhodium in photographic emulsions different sample treatment procedures were coupled with inductively coupled plasma mass spectrometry (ICP-MS) and, for iridium, also with negative thermal ionisation isotope dilution mass spectrometry (NTI-IDMS)

  12. A new method for the determination of NO2 traces using isotope dilution and mass spectrometry analysis

    International Nuclear Information System (INIS)

    Stevens, C.; Barat, F.; Nguyen Nghi, H.

    1975-01-01

    A new method for the determination of NO 2 traces, in the order of 1ppb (10 -9 ), in atmosphere and stratosphere is described. The method consists in an isotope dilution technique using 15 NO 2 , followed by the reduction of NO 2 to N 2 and a mass spectrometry analysis. A known amount of 15 NO 2 is added to the air samples. Then, NO 2 is separated from H 2 O, HNO 3 , CO 2 and N 2 O and transferred to a SiO 2 reactor by trapping at -196 deg C. In the reactor NO 2 is reduced to N 2 by reaction with electrolytic Cu heated at 580 deg C. The mass 29/mass 30 ratio corresponding to 15 N 14 N and 15 N 15 N is determined by mass spectrometry. The sensitivity of the method depends on the contamination introduced during the analysis of the sample (reagents, separation and measuring devices). The contamination is reproducible and in the order of 4.5+-0.5 10 -2 mm 3 N 2 [fr

  13. Application of inductively coupled plasma mass spectrometry (ICP/MS) to detection of trace elements, heavy metals and radioisotopes in scalp hair

    International Nuclear Information System (INIS)

    Ozturk, Yildirim; Benderli, Cihan

    2010-01-01

    Trace element analysis of human hair has the potential to reveal retrospective information about an individual's nutritional status and exposure. As trace elements are incorporated into the hair during the growth process, longitudinal segments of the hair may reflect the body burden during the growth period. it was evaluated the potential of human hair to indicate exposure or nutritional status over time by analysing trace element profiles in single strands of human hair. By using inductively coupled plasma mass spectrometry (ICP-MS), it was achieved profiles of 43 elements in single strands of human hair. It was shown that trace element analysis along single strands of human hair can yield information about essential and toxic elements and for some elements, can be correlated with seasonal changes in diet and exposure. The information obtained from the trace element profiles of human hair in this study substantiates the potential of hair as a biomarker

  14. Tracing early evolutionary stages of high-mass star formation with molecular lines

    NARCIS (Netherlands)

    Marseille, M. G.; van der Tak, F. F. S.; Herpin, F.; Jacq, T.

    2010-01-01

    Context. Despite its major role in the evolution of the interstellar medium, the formation of high-mass stars (M >= 10 M(circle dot)) remains poorly understood. Two types of massive star cluster precursors, the so-called massive dense cores (MDCs), have been observed, which differ in terms of their

  15. Large-scale correlations in gas traced by Mg II absorbers around low-mass galaxies

    Science.gov (United States)

    Kauffmann, Guinevere

    2018-03-01

    The physical origin of the large-scale conformity in the colours and specific star formation rates of isolated low-mass central galaxies and their neighbours on scales in excess of 1 Mpc is still under debate. One possible scenario is that gas is heated over large scales by feedback from active galactic nuclei (AGNs), leading to coherent modulation of cooling and star formation between well-separated galaxies. In this Letter, the metal line absorption catalogue of Zhu & Ménard is used to probe gas out to large projected radii around a sample of a million galaxies with stellar masses ˜1010M⊙ and photometric redshifts in the range 0.4 Survey imaging data. This galaxy sample covers an effective volume of 2.2 Gpc3. A statistically significant excess of Mg II absorbers is present around the red-low-mass galaxies compared to their blue counterparts out to projected radii of 10 Mpc. In addition, the equivalent width distribution function of Mg II absorbers around low-mass galaxies is shown to be strongly affected by the presence of a nearby (Rp < 2 Mpc) radio-loud AGNs out to projected radii of 5 Mpc.

  16. Resonance ionization and time-of-flight mass spectrometry for the analysis of trace substances in complex gas mixtures

    International Nuclear Information System (INIS)

    Nagel, Holger; Weickhardt, Christian; Boesl, Ulrich; Frey, Ruediger

    1995-01-01

    The analysis of mixtures of technical gases still comprises a lot of problems: the large number of components with very different and often rapidly varying concentrations makes great demands on analytical methods. By use of conventional analytical methods, signals of trace substances may interfere with signals of main components, whereas small signals representing low concentrations are covered by signals of main substances.The resonant-enhanced multiphoton ionization (REMPI) makes use of excited intermediate states of molecules. As these states are characteristic of each substance, one or more components of interest can be ionized with high efficiency without interference of other molecules by using a special laser-wavelength. The combination of the above mentioned ionization method with a reflectron time-of-flight mass spectrometer permits a very fast and sensitive detection of preselected trace substances.As ionization processes of higher order strongly depend on the laser intensity, there is no direct relation between ion signals and concentrations of exhaust components. Quantitative assessments are based on an especially developed calibration technique that makes use of internal standards. Applied under environmental aspects, this new analytical method helps to analyze a large number of components extracted from exhaust gases of combustion engines with high time resolution (<20 ms motor synchronously), high sensitivity (1 ppm) and high quantitative accuracy (more than 10%). A preliminary list of detectable compounds contains 30 substances

  17. Chemical and sewage sludge co-incineration in a full-scale MSW incinerator: toxic trace element mass balance.

    Science.gov (United States)

    Biganzoli, Laura; Grosso, Mario; Giugliano, Michele; Campolunghi, Manuel

    2012-10-01

    Co-incineration of sludges with MSW is a quite common practice in Europe. This paper illustrates a case of co-incineration of both sewage sludges and chemical sludges, the latter obtained from drinking water production, in a waste-to-energy (WTE) plant located in northern Italy and equipped with a grate furnace, and compares the toxic trace elements mass balance with and without the co-incineration of sludges. The results show that co-incineration of sewage and chemical sludges does not result in an increase of toxic trace elements the total release in environment, with the exception of arsenic, whose total release increases from 1 mg t(fuel) (-1) during standard operation to 3 mg t(fuel) (-1) when sludges are co-incinerated. The increase of arsenic release is, however, attributable to the sole bottom ashes, where its concentration is five times higher during sludge co-incineration. No variation is observed for arsenic release at the stack. This fact is a further guarantee that the co-incineration of sludges, when performed in a state-of-the-art WTE plant, does not have negative effects on the atmospheric environment.

  18. Analytical study of a gas of gluonic quasiparticles at high temperature: Effective mass, pressure, and trace anomaly

    International Nuclear Information System (INIS)

    Giacosa, Francesco

    2011-01-01

    The thermodynamical properties of a pure Yang-Mills theory SU(N) is described by a gas of gluonic quasiparticles with temperature-dependent mass m(T) and a bag function B(T). The analytic behavior of m(T) and the pressure p in the temperature range 2.5-5T c are derived and constraints on the parameters defining B(T) are discussed. The trace anomaly θ=ρ-3p is evaluated in the high T domain: it is dominated by a quadratic behavior θ=nKT 2 , where n=2(N 2 -1) is the number of degrees of freedom and K is an integration constant which does not depend on the bag function B(T). The quadratic rise of θ is in good agreement with recent lattice simulations.

  19. Development of a mass spectrometrical isotope dilution analysis for determination of trace iodine levels and its application for food samples

    International Nuclear Information System (INIS)

    Schindlmeier, W.

    1984-01-01

    A mass spectrometrical isotope dilution procedure for the determination of trace amounts of iodine in various materials was developed using 129 I as indicator isotope, based on the determination of the 129 I/ 127 I isotope relationship. Negative thermionization was used as ionization method. The analysis procedure, which worked with a standard deviation of between 0,1 and 10% (depending on material tested), was used to determine the iodine level of table salt - both iodized and normal salt (3-6 ppm and less than 0,006 ppm respectively), and food samples with an organic matrix. For comparison the iodine levels were also measured with an iodine-selective electrode. Special preparation and separation procedures were done to suit the sample material. A comparison of the levels of iodine concentration in various powdered milks which were measured by international collaborators using varying methods shows the superior reproducibility of the MS-IDA. (RB) [de

  20. Ultra-trace determination of neptunium-237 and plutonium isotopes in urine samples by compact accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dai, X.; Christl, M.; Kramer-Tremblay, S., E-mail: sheila.kramer-tremblay@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Synal, H-A. [ETH Zurich, Lab. of Ion Beam Physics, Zurich (Switzerland)

    2015-12-15

    Ultra-trace analysis of actinides, such as Pu isotopes and {sup 237}Np, in bioassay samples is often needed for radiation protection programs at nuclear facilities. Accelerator mass spectrometry (AMS), particularly the compact ETH Zurich system “Tandy”, has evolved over the years as one of the most sensitive, selective, and robust techniques for actinide analysis. Employment of the AMS technique can reduce the demands on sample preparation chemistry and increase sample analysis throughput, due to very low instrumental detection limit, high rejection of interferences, and low susceptibility to adverse sample matrices. Initial research and development tests were performed to explore and demonstrate the analytical capability of AMS for Pu and Np urine bioassay. In this study, urine samples spiked with femtogram levels of Np and Pu isotopes were prepared and measured using compact ETH AMS system and the results showed excellent analytical capability for measuring Np and Pu isotopes at femtogram/litre levels in urine. (author)

  1. The determination of low level trace elements in coals by laser ablation-inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Booth, C.A.; Spears, D.A.; Krause, P.; Cox, A.G. [University of Sheffield, Sheffield (United Kingdom). Dept. of Earth Sciences

    1999-11-01

    The rapid determination of elements present in low level concentrations in bituminous coals is possible using laser abalation-inductively coupled plasma-mass spectrometry (l.a.-i.c.p.-m.s.). A wide range of trace elements can routinely be determined using this technique but it is for environmentally sensitive elements, such as As, Cd, Mo, Sb, Se and Hg, that it is of most use due to the low levels of detection. Calibration of the i.c.p.-m.s. was achieved using a series of uncertified coals and the method evaluated using the South African certified coals, Sarm 18, 19 and 20. A critical evaluation of the data obtained shows that for many of the elements studied the results obtained are both accurate and precise, even at very low concentrations, with the limits of detection for all of the elements being in the {mu}g/kg (parts per billion) range. 6 refs., 3 figs., 9 tabs.

  2. Microwave assisted digestion of atmospheric aerosol samples followed by inductively coupled plasma mass spectrometry determination of trace elements

    Energy Technology Data Exchange (ETDEWEB)

    Swami, K.; Judd, C.D.; Orsini, J.; Yang, K.X. [New York State Dept. of Health, Albany, NY (United States). Wadsworth Center for Labs. and Research; Husain, L. [New York State Dept. of Health, Albany, NY (United States). Wadsworth Center for Labs. and Research; Dept. of Environmental Health and Toxicology, State Univ. of New York, Albany (United States)

    2001-01-01

    A microwave digestion method in a closed vessel was developed for the determination of trace metals in atmospheric aerosols using inductively coupled plasma mass spectrometry (ICP-MS). A recovery study for the elements V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sb, and Pb was conducted using multi-elemental standard solutions, NIST 1633b Trace Elements in Coal Fly Ash, and NIST 1648 Urban Particulate Matter. A simple digestion method using only HNO{sub 3}/H{sub 2}O{sub 2}gave good recoveries (90%-108%) for all elements except Cr in SRM 1648, but yielded low recoveries for SRM 1633b. A more robust method using HNO {sub 3}/H {sub 2}O {sub 2}/HF/H {sub 3}BO {sub 3} yielded higher recoveries (82%-103%) for the lighter elements (V - Zn) in SRM 1633b, and improved the Cr recovery in SRM 1648, but decreased the Se recovery in both SRMs. A comparative analysis of aerosol samples obtained at a remote mountain location Nathiagali, Pakistan (2.5 km above mean sea level), and Mayville, New York, downwind from the highly industrialized Midwestern United States, was carried out using Instrumental Neutron Activation Analysis (INAA) for the elements Cr, Mn, Fe, Co, Zn, As, Se, and Sb. The simple digestion method yielded excellent agreement for Cr, Fe, Zn, As, Se, and Sb, with slopes of the ICP-MS vs. INAA regressions of 0.90-1.00 and R {sup 2} values of 0.96-1.00. The regressions for Mn and Co had slopes of 0.82 and 0.84 with R {sup 2} values of 0.83 and 0.82, respectively. Addition of HF/H {sub 3}BO {sub 3} did not improve the correlation for any of the elements and degraded the precision somewhat. The technique provides sensitivity and accuracy for trace elements in relatively small aerosol samples used in atmospheric chemistry studies related to SO {sub 2} oxidation in cloud droplets. The ability to determine concentrations of a very large number of elements from a single analysis will permit source apportionment of various trace pollutants and hence strategies to control the

  3. Combined liquid chromatography-mass spectrometry for trace analysis of pharmaceuticals

    International Nuclear Information System (INIS)

    Schmidt, L.; Danigel, H.; Jungclas, H.

    1982-01-01

    A 252 Cf-plasma desorption mass spectrometer (PDMS) for the analysis of thin layers from nonvolatile organic samples has been set up to be combined with a liquid chromatograph. A novel interface performs the direct inlet of the liquid sample through a capillary into the vacuum system of the spectrometer. Samples of drugs are periodically collected, transferred to the ion source and analysed using a rotating disk. This on-line sample preparation has been tested for three antiarrhythmic drugs using various solvents and mixtures. (orig.)

  4. Connecting traces of galaxy evolution: the missing core mass-morphological fine structure relation

    Science.gov (United States)

    Bonfini, P.; Bitsakis, T.; Zezas, A.; Duc, P.-A.; Iodice, E.; González-Martín, O.; Bruzual, G.; González Sanoja, A. J.

    2018-01-01

    Deep exposure imaging of early-type galaxies (ETGs) are revealing the second-order complexity of these objects, which have been long considered uniform, dispersion-supported spheroidals. `Fine structure' features (e.g. ripples, plumes, tidal tails, rings) as well as depleted stellar cores (i.e. central light deficits) characterize a number of massive ETG galaxies, and can be interpreted as the result of galaxy-galaxy interactions. We discuss how the time-scale for the evolution of cores and fine structures are comparable, and hence it is expected that they develop in parallel after the major interaction event which shaped the ETG. Using archival data, we compare the `depleted stellar mass' (i.e. the mass missing from the depleted stellar core) against the prominence of the fine structure features, and observe that they correlate inversely. This result confirms our expectation that, while the supermassive black hole (SMBH) binary (constituted by the SMBHs of the merger progenitors) excavates the core via three-body interactions, the gravitational potential of the newborn galaxy relaxes, and the fine structures fade below detection levels. We expect the inverse correlation to hold at least within the first Gyr from the merger which created the SMBH binary; after then, the fine structure evolves independently.

  5. Laser ablation inductively coupled plasma mass spectrometry for the determination of trace elements in soil

    International Nuclear Information System (INIS)

    Lee Yiling; Chang Chaochiang; Jiang Shiuhjen

    2003-01-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been applied to the determination of Cr, Cu, Zn, Cd and Pb in soil samples. The dried soil powder was pressed into a pellet for LA-ICP-MS analysis. Triton X-100 was added to work as the modifier to enhance the ion signals. The influences of instrument operating conditions (LA and ICP-MS) and pellet preparation on the ion signals were reported. For Cr determination, the ICP-MS was operated under the dynamic reaction cell mode which alleviated the mass overlap interference. Standard addition method and isotope dilution method were used for the quantitation work. The powder sample was spiked with suitable amounts of element standards and/or enriched isotopes, well-mixed, dried and then pressed into a pellet for LA-ICP-MS analysis. This method has been applied to determine Cr, Cu, Zn, Cd and Pb in NIST SRM 2711 Montana soil and NIST SRM 2709 San Joaquin soil reference materials. The analysis results were in agreement with the certified values. The precision between sample replicates was better than 5% with LA-ICP-MS method. Detection limits estimated from standard addition curves were approximately 0.9, 2, 9, 0.7 and 0.3 ng g -1 for Cr, Cu, Zn, Cd and Pb, respectively

  6. Determination of trace amounts of rare earth elements in various environmental samples by spark source mass spectrography

    International Nuclear Information System (INIS)

    Sugimae, Akiyoshi

    1978-01-01

    A chemical concentration-mass spectrographic procedure was described for the determination of trace amounts of rare earth elements in various environmental samples: airborne particulate matter, dustfall, soil and so forth. A 0.5 to 1 gram of sample material was decomposed by fusion with sodium carbonate. The silica dehydrated in the usual way was filtered off and the filtrate from the silica was then treated with ammonium hydroxide to precipitate the rare earth elements. After ignition of the precipitate, two ml of internal standard solution containing 20 μg/ml of silver were added and the mixture was then evaporated to dryness. The residue was mixed with an equal amount of graphite powder and then pressed into electrodes. Relative sensitivity coefficients (Ag=1.0) were determined by using Spex Mix and U. S. Geological Survey rock standard G-2. U. S. Geological Survey rock standard GSP-1 and N.B.S. coal fly ash SRM 1633 were analysed to evaluate the accuracy of the proposed method. Comparison of the mass spectral values with literature ones indicated a good agreement. The coefficient of variation obtained by replicate analysis of SRM 1633 was better than 25%. The proposed method was applied to the determination of rare earth elements in airborne particulate matter and dustfall collected on polystyrene filter and in dustjars, respectively. Results for the rare earth elements in the blank of glass fiber filter which was widely used for the collection of airborne particulate matter were also presented. (auth.)

  7. Application of slurry nebulization to trace elemental analysis of some biological samples by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Mochizuki, T.; Sakashita, A.; Iwata, H.; Ishibashi, Y.; Gunji, N.

    1991-01-01

    The application of slurry nebulization/inductively coupled plasma mass spectrometry (ICP-MS) to trace elemental analysis of biological samples has been investigated. Three standard samples of the National Institute of Standards and Technology (NIST) were dispersed in 1% aqueous Triton X-100 solution by grinding with a planetary micronizing mill. The resulting slurries were nebulized into an ICP without any additional treatments. The 1% (m/v) slurry of the NIST bovine liver showed no significant influence on cone blockage and signal suppression/enhancement. Detection limit, precision and accuracy were discussed for the determination of 24 elements of interest in bovine liver, rice flour and pine needles. Detection limits ranged from 0.0001 μg g -1 for U to 0.52 μg g -1 for Zn at the effective integrating time of 10 s. For high mass elements, low blank values were obtained, yielding excellent limits ( -1 ). Acceptable accuracy and precision were obtained for most of the elements in the NIST bovine liver and rice flour, even for the volatile elements, such as As, Se and Br. However, relatively poor accuracy was obtained for the analysis of pine needles. (orig.)

  8. TRACING MOLECULAR GAS MASS IN EXTREME EXTRAGALACTIC ENVIRONMENTS: AN OBSERVATIONAL STUDY

    International Nuclear Information System (INIS)

    Zhu Ming; Papadopoulos, Padeli P.; Xilouris, Emmanuel M.; Kuno, Nario; Lisenfeld, Ute

    2009-01-01

    We present a new observational study of the 12 CO(1-0) line emission as an H 2 gas mass tracer under extreme conditions in extragalactic environments. Our approach is to study the full neutral interstellar medium (H 2 , H I, and dust) of two galaxies whose bulk interstellar medium (ISM) resides in environments that mark (and bracket) the excitation extremes of the ISM conditions found in infrared luminous galaxies, the starburst NGC 3310, and the quiescent spiral NGC 157. Our study maintains a robust statistical notion of the so-called X = N(H 2 )/I CO factor (i.e., a large ensemble of clouds is involved) while exploring its dependence on the very different average ISM conditions prevailing within these two systems. These are constrained by fully sampled 12 CO(3-2) and 12 CO(1-0) observations, at a matched beam resolution of half-power beam width ∼15'', obtained with the James Clerk Maxwell Telescope (JCMT) on Mauna Kea (Hawaii) and the 45 m telescope of the Nobeyama Radio Observatory in Japan, combined with sensitive 850 μm and 450 μm dust emission and H I interferometric images which allow a complete view of all the neutral ISM components. Complementary 12 CO(2-1) observations were obtained with the JCMT toward the center of the two galaxies. We found an X factor varying by a factor of 5 within the spiral galaxy NGC 157 and about two times lower than the Galactic value in NGC 3310. In addition, the dust emission spectrum in NGC 3310 shows a pronounced submillimeter 'excess'. We tried to fit this excess by a cold dust component but very low temperatures were required (T C ∼ 5-11 K) with a correspondingly low gas-to-dust mass ratio of ∼5-43. We furthermore show that it is not possible to maintain the large quantities of dust required at these low temperatures in this starburst galaxy. Instead, we conclude that the dust properties need to be different from Galactic dust in order to fit the submillimeter 'excess'. We show that the dust spectral energy

  9. Trace metal analysis of road dust by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Powell, M.J.; Liu, L.; Gnanalingham, N.; Peters, L.

    2000-01-01

    Dust from roads in an air impingement zone close to anthropogenic sources of air pollutants can be a concern for people living in the immediate vicinity. The Ministry of the Environment (MOE) has conducted a case study to monitor the concentration of uranium, strontium, thorium and arsenic in road dust from one such area. A method for the analysis of road dust by inductively coupled plasma mass spectrometry (ICP-MS) has been developed with detection limits in the ng/1 range. A digestion technique has been developed by conducting experiments using single and combinations of acids in open-vessel wet digestions. Accuracy has been determined by the use of matrix representative certified reference materials (CRMs). Digestion precision was determined by elemental concentration measurements of the most representative CRM through replicates. Spike recovery data were from 95% to 110% for all elements, and inter-method comparison studies between hydride generation atomic absorption spectrometry (AAS) inductively coupled plasma atomic emission spectrometry (ICP-AES) and ICP-MS for arsenic and strontium show good agreement. (author)

  10. Certification of Trace Elements and Methyl Mercury Mass Fractions in IAEA-470 Oyster Sample

    International Nuclear Information System (INIS)

    2016-01-01

    This publication describes the production of the IAEA-470 certified reference material, which was produced following ISO Guide 34:2009, General Requirements for the Competence of Reference Materials Producers. A sample of approximately 10 kg of dried oysters was taken from oysters collected, dissected and freeze-dried by the Korean Ocean Research and Development Institute, and was further processed at the IAEA Environment Laboratories to produce a certified reference material. The sample contained certified mass fractions for arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, mercury, methyl mercury, rubidium, selenium, silver, sodium, strontium, vanadium and zinc. The produced vials containing the processed oyster sample were carefully capped and stored for further certification studies. Between-unit homogeneity and stability during dispatch and storage were quantified in accordance with ISO Guide 35:2006, Reference Materials - General and Statistical Principles for Certification. The material was characterized by laboratories with demonstrated competence and adhering to ISO/IEC 17025:2005. Uncertainties of the certified values were calculated in compliance with the guide to the Expression of Uncerdainty in Measurement (JCGM 100:2008), including uncertainty associated with heterogeneity and instability of the material, and with the characterization itself. The material is intended for the quality control and assessment of method performance. As with any reference material, it can also be used for control charts or validation studies

  11. Development of realtime monitoring technology for laser photoreaction product - Development of glow discharge-mass spectrometry (GD-MS) hybrid techniques for trace analysis of refractory elements

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Chun [Kyungnam University, Masan (Korea); Kim, Ha Suck [Seoul National University, Seoul (Korea); Kim, Hyo Jin [Dongduk Women' s University, Seoul (Korea)

    2000-04-01

    This research is focusing on development of hybrid techniques of glow discharge-mass spectrometry for the trace analysis of refractory elements. At first, we developed a glow discharge(GD) ionization cell and its characteristics was investigated. The new GD cell was designed based on direct current hollow cathode glow discharge and it is used for quadrupole mass analyzer and time-of-flight mass analyzer. Currently, GD-quadrupole mass spectrometry is working for the analysis of refractory elements. The experimental results show relatively good for trace analysis. In addition, ion mobile spectrometry using plasma and liquid discharge technique were investigated for the analysis of refractory elements and both techniques need more investigation to deduce the their usefulness. 30 refs., 67 figs., 4 tabs. (Author)

  12. A general method for the calculation of absolute trace gas concentrations in air and breath from selected ion flow tube mass spectrometry data

    Czech Academy of Sciences Publication Activity Database

    Španěl, Patrik; Dryahina, Kseniya; Smith, D.

    249-250, - (2006), s. 230-239 ISSN 1387-3806 R&D Projects: GA ČR GA202/03/0827 Institutional research plan: CEZ:AV0Z40400503 Keywords : selected ion flow tube * mass spectrometry * SIFT-MS * trace gas analysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.337, year: 2006

  13. THE H I MASS DENSITY IN GALACTIC HALOS, WINDS, AND COLD ACCRETION AS TRACED BY Mg II ABSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    Kacprzak, Glenn G. [Swinburne University of Technology, Victoria 3122 (Australia); Churchill, Christopher W., E-mail: gkacprzak@astro.swin.edu.au, E-mail: cwc@nmsu.edu [New Mexico State University, Las Cruces, NM 88003 (United States)

    2011-12-20

    It is well established that Mg II absorption lines detected in background quasar spectra arise from gas structures associated with foreground galaxies. The degree to which galaxy evolution is driven by the gas cycling through halos is highly uncertain because their gas mass density is poorly constrained. Fitting the Mg II equivalent width (W) distribution with a Schechter function and applying the N(H I)-W correlation of Menard and Chelouche, we computed {Omega}(H I){sub MgII} {identical_to} {Omega}(H I){sub halo} = 1.41{sup +0.75}{sub -0.44} Multiplication-Sign 10{sup -4} for 0.4 {<=} z {<=} 1.4. We exclude damped Ly{alpha}'s (DLAs) from our calculations so that {Omega}(H I){sub halo} comprises accreting and/or outflowing halo gas not locked up in cold neutral clouds. We deduce that the cosmic H I gas mass density fraction in galactic halos traced by Mg II absorption is {Omega}(H I){sub halo}/{Omega}(H I){sub DLA} {approx_equal} 15% and {Omega}(H I){sub halo}/{Omega}{sub b} {approx_equal} 0.3%. Citing several lines of evidence, we propose that infall/accretion material is sampled by small W whereas outflow/winds are sampled by large W, and find that {Omega}(H I){sub infall} is consistent with {Omega}(H I){sub outflow} for bifurcation at W = 1.23{sup +0.15}{sub -0.28} Angstrom-Sign ; cold accretion would then comprise no more than {approx}7% of the total H I mass density. We discuss evidence that (1) the total H I mass cycling through halos remains fairly constant with cosmic time and that the accretion of H I gas sustains galaxy winds, and (2) evolution in the cosmic star formation rate depends primarily on the rate at which cool H I gas cycles through halos.

  14. Quantification of Stable Isotope Traces Close to Natural Enrichment in Human Plasma Metabolites Using Gas Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Krämer, Lisa; Jäger, Christian; Trezzi, Jean-Pierre; Jacobs, Doris M; Hiller, Karsten

    2018-02-14

    Currently, changes in metabolic fluxes following consumption of stable isotope-enriched foods are usually limited to the analysis of postprandial kinetics of glucose. Kinetic information on a larger diversity of metabolites is often lacking, mainly due to the marginal percentage of fully isotopically enriched plant material in the administered food product, and hence, an even weaker 13 C enrichment in downstream plasma metabolites. Therefore, we developed an analytical workflow to determine weak 13 C enrichments of diverse plasma metabolites with conventional gas chromatography-mass spectrometry (GC-MS). The limit of quantification was increased by optimizing (1) the metabolite extraction from plasma, (2) the GC-MS measurement, and (3) most importantly, the computational data processing. We applied our workflow to study the catabolic dynamics of 13 C-enriched wheat bread in three human subjects. For that purpose, we collected time-resolved human plasma samples at 16 timepoints after the consumption of 13 C-labeled bread and quantified 13 C enrichment of 12 metabolites (glucose, lactate, alanine, glycine, serine, citrate, glutamate, glutamine, valine, isoleucine, tyrosine, and threonine). Based on isotopomer specific analysis, we were able to distinguish catabolic profiles of starch and protein hydrolysis. More generally, our study highlights that conventional GC-MS equipment is sufficient to detect isotope traces below 1% if an appropriate data processing is integrated.

  15. Visualizing fossilization using laser ablation-inductively coupled plasma-mass spectrometry maps of trace elements in Late Cretaceous bones

    Science.gov (United States)

    Koenig, A.E.; Rogers, R.R.; Trueman, C.N.

    2009-01-01

    Elemental maps generated by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) provide a previously unavailable high-resolution visualization of the complex physicochemical conditions operating within individual bones during the early stages of diagenesis and fossilization. A selection of LA-ICP-MS maps of bones collected from the Late Cretaceous of Montana (United States) and Madagascar graphically illustrate diverse paths to recrystallization, and reveal unique insights into geochemical aspects of taphonomic history. Some bones show distinct gradients in concentrations of rare earth elements and uranium, with highest concentrations at external bone margins. Others exhibit more intricate patterns of trace element uptake related to bone histology and its control on the flow paths of pore waters. Patterns of element uptake as revealed by LA-ICP-MS maps can be used to guide sampling strategies, and call into question previous studies that hinge upon localized bulk samples of fossilized bone tissue. LA-ICP-MS maps also allow for comparison of recrystallization rates among fossil bones, and afford a novel approach to identifying bones or regions of bones potentially suitable for extracting intact biogeochemical signals. ?? 2009 Geological Society of America.

  16. Trace determination of the flame retardant tetrabromobisphenol A in the atmosphere by gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Xie Zhiyong; Ebinghaus, Ralf; Lohmann, Rainer; Heemken, Olaf; Caba, Armando; Puettmann, Wilhelm

    2007-01-01

    A simple and effective method has been developed for analysis of the flame retardant tetrabromobisphenol A (TBBPA) in environmental samples by using modified soxhlet extraction in combination with silica gel clean-up, derivatization with silylation reagent and gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring mode (SIM). Satisfactory recoveries were achieved for the large volume sampling, soxhlet extraction and silica gel clean-up. The overall recovery is 79 ± 1%. The derivatization procedure is simple and fast, and produces stable TBBPA derivative. GC-MS with electronic impact (EI) ionization mode shows better detection power than using negative chemical ionization (NCI) mode. EI gives a method detection limit of 0.04 pg m -3 and enables to determine trace TBBPA in ambient air in remote area. The method was successfully applied to the determination of TBBPA in atmospheric samples collected over land and coastal regions. The concentrations of TBBPA ranged from below the method detection limit (0.04 pg m -3 ) to 0.85 pg m -3 . A declining trend with increasing latitude was present from the Wadden Sea to the Arctic. The atmospheric occurrence of TBBPA in the Arctic is significant and might imply that TBBPA has long-range transport potential

  17. Quantification of Stable Isotope Traces Close to Natural Enrichment in Human Plasma Metabolites Using Gas Chromatography-Mass Spectrometry

    Science.gov (United States)

    Krämer, Lisa; Jäger, Christian; Jacobs, Doris M.; Hiller, Karsten

    2018-01-01

    Currently, changes in metabolic fluxes following consumption of stable isotope-enriched foods are usually limited to the analysis of postprandial kinetics of glucose. Kinetic information on a larger diversity of metabolites is often lacking, mainly due to the marginal percentage of fully isotopically enriched plant material in the administered food product, and hence, an even weaker 13C enrichment in downstream plasma metabolites. Therefore, we developed an analytical workflow to determine weak 13C enrichments of diverse plasma metabolites with conventional gas chromatography-mass spectrometry (GC-MS). The limit of quantification was increased by optimizing (1) the metabolite extraction from plasma, (2) the GC-MS measurement, and (3) most importantly, the computational data processing. We applied our workflow to study the catabolic dynamics of 13C-enriched wheat bread in three human subjects. For that purpose, we collected time-resolved human plasma samples at 16 timepoints after the consumption of 13C-labeled bread and quantified 13C enrichment of 12 metabolites (glucose, lactate, alanine, glycine, serine, citrate, glutamate, glutamine, valine, isoleucine, tyrosine, and threonine). Based on isotopomer specific analysis, we were able to distinguish catabolic profiles of starch and protein hydrolysis. More generally, our study highlights that conventional GC-MS equipment is sufficient to detect isotope traces below 1% if an appropriate data processing is integrated. PMID:29443915

  18. Quantification of Stable Isotope Traces Close to Natural Enrichment in Human Plasma Metabolites Using Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Lisa Krämer

    2018-02-01

    Full Text Available Currently, changes in metabolic fluxes following consumption of stable isotope-enriched foods are usually limited to the analysis of postprandial kinetics of glucose. Kinetic information on a larger diversity of metabolites is often lacking, mainly due to the marginal percentage of fully isotopically enriched plant material in the administered food product, and hence, an even weaker 13C enrichment in downstream plasma metabolites. Therefore, we developed an analytical workflow to determine weak 13C enrichments of diverse plasma metabolites with conventional gas chromatography-mass spectrometry (GC-MS. The limit of quantification was increased by optimizing (1 the metabolite extraction from plasma, (2 the GC-MS measurement, and (3 most importantly, the computational data processing. We applied our workflow to study the catabolic dynamics of 13C-enriched wheat bread in three human subjects. For that purpose, we collected time-resolved human plasma samples at 16 timepoints after the consumption of 13C-labeled bread and quantified 13C enrichment of 12 metabolites (glucose, lactate, alanine, glycine, serine, citrate, glutamate, glutamine, valine, isoleucine, tyrosine, and threonine. Based on isotopomer specific analysis, we were able to distinguish catabolic profiles of starch and protein hydrolysis. More generally, our study highlights that conventional GC-MS equipment is sufficient to detect isotope traces below 1% if an appropriate data processing is integrated.

  19. Scanning transmission ion microscopy mass measurements for quantitative trace element analysis within biological samples and validation using atomic force microscopy thickness measurements

    Energy Technology Data Exchange (ETDEWEB)

    Deves, Guillaume [Laboratoire de chimie nucleaire analytique et bioenvironnementale, UMR 5084, CNRS-Universite de Bordeaux 1, BP 120 Chemin du solarium, F33175 Gradignan cedex (France)]. E-mail: deves@cenbg.in2p3.fr; Cohen-Bouhacina, Touria [Centre de Physique Moleculaire Optique et Hertzienne, Universite de Bordeaux 1, 351, cours de la Liberation, F33405 Talence cedex (France); Ortega, Richard [Laboratoire de chimie nucleaire analytique et bioenvironnementale, UMR 5084, CNRS-Universite de Bordeaux 1, BP 120 Chemin du solarium, F33175 Gradignan cedex (France)

    2004-10-08

    We used the nuclear microprobe techniques, micro-PIXE (particle-induced X-ray emission), micro-RBS (Rutherford backscattering spectrometry) and scanning transmission ion microscopy (STIM) in order to perform the characterization of trace element content and spatial distribution within biological samples (dehydrated cultured cells, tissues). The normalization of PIXE results was usually expressed in terms of sample dry mass as determined by micro-RBS recorded simultaneously to micro-PIXE. However, the main limit of RBS mass measurement is the sample mass loss occurring during irradiation and which could be up to 30% of the initial sample mass. We present here a new methodology for PIXE normalization and quantitative analysis of trace element within biological samples based on dry mass measurement performed by mean of STIM. The validation of STIM cell mass measurements was obtained in comparison with AFM sample thickness measurements. Results indicated the reliability of STIM mass measurement performed on biological samples and suggested that STIM should be performed for PIXE normalization. Further information deriving from direct confrontation of AFM and STIM analysis could as well be obtained, like in situ measurements of cell specific gravity within cells compartment (nucleolus and cytoplasm)

  20. Tracing discharges of plutonium and technetium from nuclear processing plants by ultra-sensitive accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Fifield, L.K.; Hausladen, P.A.; Cresswell, R.G.; Di Tada, M.L.; Day, J.P.; Carling, R.S.; Oughton, D.H.

    1999-01-01

    Historical discharges of plutonium from the Russian nuclear processing plant at Mayak in the Urals have been traced in sediments, soils and river water using ultra-sensitive detection of plutonium isotopes by accelerator mass spectrometry (AMS). Significant advantages of AMS over other techniques are its very high sensitivity. which is presently ∼10 6 atoms (1 μBq), and its ability to determine the 240 Pu/ 239 Pu ratio. The latter is a sensitive indicator of the source of the plutonium, being very low (1-2%) for weapons grade plutonium, and higher (∼ 20%) for plutonium from civil reactors or fallout from nuclear weapons testing. Since this ratio has changed significantly over the years of discharges from Mayak, a measurement can provide important information about the source of plutonium at a particular location. Similar measurements have been performed on samples from the Kara Sea which contains a graveyard of nuclear submarines from the former Soviet Union. AMS techniques have also been developed for detection of 99 Tc down to levels of a few femtograms. This isotope is one of the most prolific fission products and has a very long half-life of 220 ka. Hundreds of kg have been discharged from the nuclear reprocessing plant at Sellafield in the UK. While there may be public health issues associated with these discharges which can be addressed with AMS, these discharges may also constitute a valuable oceanographic tracer experiment in this climatically-important region of the world's oceans. Applications to date have included a human uptake study to assess long-term retention of 99 Tc in the body, and a survey of seaweeds from northern Europe to establish a baseline for a future oceanographic study

  1. The determination of the C, N, O and trace element content of Triticum aestivum by activation analysis, X-ray excitation and mass spectrometry

    International Nuclear Information System (INIS)

    Leonhardt, J.W.; Dahn, E.; Dietze, H.J.; Freyer, K.; Geisler, M.; Hartmann, G.; Jung, K.; Schelhorn, H.

    1979-01-01

    The results of determinations of the C, N, O and trace element content of grains, sprouts and leaves of Triticum aestivum by means of various methods of activation analysis, X-ray excitation and mass spectrometry are presented. The C and O contents were determined by X-ray excitation; the O, N, P and Si contents were measured by NAA with 14-MeV neutrons, and the trace elements were determined by NAA with thermal neutrons. A mass-spectrometric survey analysis confirmed the results obtained by NAA. The use of neutron-induced nuclear reactions together with autoradiography enabled a representative picture to be formed of the spatial distribution in two dimensions of 14 N in biological specimens. (author)

  2. Rapid determination of trace nitrophenolic organics in water by combining solid-phase extraction with surface-assisted laser desorption/ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Chen, Y C; Shiea, J; Sunner, J

    2000-01-01

    A rapid technique for the screening of trace compounds in water by combining solid-phase extraction (SPE) with activated carbon surface-assisted laser desorption/ionization (SALDI) time-of-flight mass spectrometry is demonstrated. Activated carbon is used both as the sorbent in SPE and as the solid in the SALDI matrix system. This eliminates the need for an SPE elution process. After the analytes have been adsorbed on the surfaces of the activated carbon during SPE extraction, the activated carbon is directly mixed with the SALDI liquid and mass spectrometric analysis is performed. Trace phenolic compounds in water were used to demonstrate the effectiveness of the method. The detection limit for these compounds is in the ppb to ppt range. Copyright 2000 John Wiley & Sons, Ltd.

  3. Ultra-trace determination of Persistent Organic Pollutants in Artic ice using stir bar sorptive extraction and gas chromatography coupled to mass spectrometry

    OpenAIRE

    Lacorte Bruguera, Silvia; Quintana, Jordi; Tauler, Romà; Ventura, Francesc; Tovar-Sánchez, Antonio; Duarte, Carlos M.

    2010-01-01

    This study presents the optimization and application of an analytical method based on the use of stirbarsorptiveextraction (SBSE) gaschromatographycoupled to massspectrometry (GC–MS) for the ultra-trace analysis of POPs (PersistentOrganicPollutants) in Arctic ice. In a first step, the mass-spectrometry conditions were optimized to quantify 48 compounds (polycyclic aromatic hydrocarbons, brominated diphenyl ethers, chlorinated biphenyls, and organochlorinated pesticides) at the low pg/L level....

  4. Mass loading of selected major and trace elements in Lake Fork Creek near Leadville, Colorado, September-October 2001

    Science.gov (United States)

    Walton-Day, Katherine; Flynn, Jennifer L.; Kimball, Briant A.; Runkel, Robert L.

    2005-01-01

    load to the stream were the parts of the study reach containing inflow from the tribu-taries Halfmoon Creek (calcium) and Willow Creek (sulfate). The Arkansas River and its tributaries upstream from Lake Fork Creek were the source of most of the calcium (70 percent), sulfate (82 percent), manganese (77 percent), lead (78 percent), and zinc (95 percent) loads in the Arkansas River downstream from the Lake Fork confluence. In contrast, Lake Fork Creek was the major source of aluminum (68 percent), copper (65 percent), and iron (87 percent) loads to the Arkansas River downstream from the confluence. Attenuation was not important for calcium, sulfate, or iron. However, other metals loads were reduced up to 81 percent over the study reach (aluminum, 25 percent; copper, 20 percent; manganese, 81 percent; lead, 30 percent; zinc, 72 percent). Metal attenuation in the stream occurred primarily in three locations (1) the irrigation diversion ditch; (2) the beaver pond complex extending from upstream from the Colorado Gulch inflow to just downstream from that inflow; and (3) the stream reach that included the inflow from Willow Creek. The most likely attenuation mechanism is precipitation of metal oxides and hydroxides (primarily manganese), and sorption or coprecipitation of trace elements with the precipitating phase. A mass-balance calculation indicated that the wetland between the Dinero Tunnel and Lake Fork Creek removed iron, had little effect on zinc mass load, and was a source for, or was releasing, aluminum and manganese. In contrast, the wetland that occurred between the Siwatch Tunnel and Lake Fork Creek removed aluminum, iron, manganese, and zinc from the tunnel drainage before it entered the creek. Inflow from the National Fish Hatchery increased dissolved organic carbon concentrations in Lake Fork Creek and slightly changed the composition of the dissolved organic carbon. However, dissolved organic carbon loads increased in the stream reach downs

  5. Sampling strategy and analysis of trace element concentrations by inductively coupled plasma mass spectrometry on medieval human bones--the concept of chemical life history.

    Science.gov (United States)

    Skytte, Lilian; Rasmussen, Kaare Lund

    2013-07-30

    Medieval human bones have the potential to reveal diet, mobility and treatment of diseases in the past. During the last two decades trace element chemistry has been used extensively in archaeometric investigations revealing such data. Many studies have reported the trace element inventory in only one sample from each skeleton - usually from the femur or a tooth. It cannot a priori be assumed that all bones or teeth in a skeleton will have the same trace element concentrations. Six different bone and teeth samples from each individual were carefully decontaminated by mechanical means. Following dissolution of ca. 20 mg sample in nitric acid and hydrogen peroxide the assays were performed using inductively coupled plasma mass spectrometry (ICPMS) with quadropole detection. We describe the precise sampling technique as well as the analytical methods and parameters used for the ICPMS analysis. The places of sampling in the human skeleton did exhibit varying trace element concentrations. Although the samples are contaminated by Fe, Mn and Al from the surrounding soil where the bones have been residing for more than 500 years, other trace elements are intact within the bones. It is shown that the elemental ratios Sr/Ca and Ba/Ca can be used as indicators of provenance. The differences in trace element concentrations can be interpreted as indications of varying diet and provenance as a function of time in the life of the individual - a concept which can be termed chemical life history. A few examples of the results of such analyses are shown, which contains information about provenance and diagenesis. Copyright © 2013 John Wiley & Sons, Ltd.

  6. Trace analysis of total naphthenic acids in aqueous environmental matrices by liquid chromatography/mass spectrometry-quadrupole time of flight mass spectrometry direct injection.

    Science.gov (United States)

    Brunswick, Pamela; Shang, Dayue; van Aggelen, Graham; Hindle, Ralph; Hewitt, L Mark; Frank, Richard A; Haberl, Maxine; Kim, Marcus

    2015-07-31

    A rapid and sensitive liquid chromatography quadrupole time of flight method has been established for the determination of total naphthenic acid concentrations in aqueous samples. This is the first methodology that has been adopted for routine, high resolution, high throughput analysis of total naphthenic acids at trace levels in unprocessed samples. A calibration range from 0.02 to 1.0μgmL(-1) total Merichem naphthenic acids was validated and demonstrated excellent accuracy (97-111% recovery) and precision (1.9% RSD at 0.02μgmL(-1)). Quantitative validation was also demonstrated in a non-commercial oil sands process water (OSPW) acid extractable organics (AEOs) fraction containing a higher percentage of polycarboxylic acid isomers than the Merichem technical mix. The chromatographic method showed good calibration linearity of ≥0.999 RSQ to 0.005μgmL(-1) total naphthenic acids with a precision <3.1% RSD and a calculated detection limit of 0.0004μgmL(-1) employing Merichem technical mix reference material. The method is well suited to monitoring naturally occurring and industrially derived naphthenic acids (and other AEOs) present in surface and ground waters in the vicinity of mining developments. The advantage of the current method is its direct application to unprocessed environmental samples and to examine natural naphthenic acid isomer profiles. It is noted that where the isomer profile of samples differs from that of the reference material, results should be considered semi-quantitative due to the lack of matching isomer content. The fingerprint profile of naphthenic acids is known to be transitory during aging and the present method has the ability to adapt to monitoring of these changes in naphthenic acid content. The method's total ion scan approach allows for data previously collected to be examined retrospectively for specific analyte mass ions of interest. A list of potential naphthenic acid isomers that decrease in response with aging is proposed

  7. Determination of minor and trace elements in aromatic spices by micro-wave assisted digestion and inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Khan, Naeem; Choi, Ji Yeon; Nho, Eun Yeong; Jamila, Nargis; Habte, Girum; Hong, Joon Ho; Hwang, In Min; Kim, Kyong Su

    2014-09-01

    This study aimed at analyzing the concentrations of 23 minor and trace elements in aromatic spices by inductively coupled plasma-mass spectrometry (ICP-MS), after wet digestion by microwave system. The analytical method was validated by linearity, detection limits, precision, accuracy and recovery experiments, obtaining satisfactory values in all cases. Results indicated the presence of variable amounts of both minor and trace elements in the selected aromatic spices. Manganese was high in cinnamon (879.8 μg/g) followed by cardamom (758.1 μg/g) and clove (649.9 μg/g), strontium and zinc were high in ajwain (489.9 μg/g and 84.95 μg/g, respectively), while copper was high in mango powder (77.68 μg/g). On the whole some of the minor and essential trace elements were found to have good nutritional contribution in accordance to RDA. The levels of toxic trace elements, including As, Cd, and Pb were very low and did not found to pose any threat to consumers. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Trace Element Analysis of Minerals in Magmatic-Hydrothermal Ores by Laser Ablation Inductively-Coupled Plasma Mass Spectrometry: Approaches and Opportunities

    Directory of Open Access Journals (Sweden)

    Nigel Cook

    2016-10-01

    Full Text Available Laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS has rapidly established itself as the method of choice for generation of multi-element datasets for specific minerals, with broad applications in Earth science. Variation in absolute concentrations of different trace elements within common, widely distributed phases, such as pyrite, iron-oxides (magnetite and hematite, and key accessory minerals, such as apatite and titanite, can be particularly valuable for understanding processes of ore formation, and when trace element distributions vary systematically within a mineral system, for a vector approach in mineral exploration. LA-ICP-MS trace element data can assist in element deportment and geometallurgical studies, providing proof of which minerals host key elements of economic relevance, or elements that are deleterious to various metallurgical processes. This contribution reviews recent advances in LA-ICP-MS methodology, reference standards, the application of the method to new mineral matrices, outstanding analytical uncertainties that impact on the quality and usefulness of trace element data, and future applications of the technique. We illustrate how data interpretation is highly dependent on an adequate understanding of prevailing mineral textures, geological history, and in some cases, crystal structure.

  9. Determination of trace quaternary ammonium surfactants in water by combining solid-phase extraction with surface-assisted laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Chen, Y C; Sun, M C

    2001-01-01

    This study demonstrates the feasibility of combining solid-phase extraction (SPE) with surface-assisted laser desorption/ionization (SALDI) mass spectrometry to determine trace quaternary ammonium surfactants in water. The trace surfactants in water were directly concentrated on the surface of activated carbon sorbent in SPE. The activated carbon sorbent was then mixed with the SALDI liquid for SALDI analysis. No SPE elution procedure was necessary. Experimental results indicate that the surfactants with longer chain alkyl groups exhibit higher sensitivities than those with shorter chain alkyl groups in SPE-SALDI analysis. The detection limit for hexadecyltrimethylammonium bromide is around 10 ppt in SPE-SALDI analysis by sampling 100 mL of aqueous solution, while that of tetradecyltrimethylammonium bromide is about 100 ppt. The detection limit for decyltrimethylammonium bromide and dodecyltrimethylammonium bromide is in the low-ppb range. Copyright 2001 John Wiley & Sons, Ltd.

  10. The airborne mass spectrometer AIMS – Part 2: Measurements of trace gases with stratospheric or tropospheric origin in the UTLS

    Directory of Open Access Journals (Sweden)

    T. Jurkat

    2016-04-01

    an isotopically labeled 34SO2 standard. In addition, we report on trace gas measurements of HONO, which is sensitive to the reaction with SF5−. The detection limit for the various trace gases is in the low 10 pptv range at a 1 s time resolution with an overall uncertainty of the measurement of the order of 20 %. AIMS has been integrated and successfully operated on the DLR research aircraft Falcon and HALO (High Altitude LOng range research aircraft. As an example, measurements conducted during the TACTS/ESMVal (Transport and Composition of the LMS/UT and Earth System Model Validation mission with HALO in 2012 are presented, focusing on a classification of tropospheric and stratospheric influences in the UTLS region. The combination of AIMS measurements with other measurement techniques yields a comprehensive picture of the sulfur, chlorine and reactive nitrogen oxide budget in the UTLS. The different trace gases measured with AIMS exhibit the potential to gain a better understanding of the trace gas origin and variability at and near the tropopause.

  11. Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

    Science.gov (United States)

    An analytical method to identify and quantify trace levels of C5 to C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOC) is developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60...

  12. Characterization of flux-grown Trace-element-doped titanite using the high-mass-resolution ion microprobe (SHRIMP-RG)

    Science.gov (United States)

    Mazdab, F.K.

    2009-01-01

    Crystals of titanite can be readily grown under ambient pressure from a mixture of CaO, TiO2 and SiO2 in the presence of molten sodium tetraborate. The crystals produced are euhedral and prismatic, lustrous and transparent, and up to 5 mm in length. Titanite obtained by this method contains approximately 4300 ppm Na and 220 ppm B contributed from the flux. In addition to dopant-free material, titanite containing trace alkali and alkaline earth metals (K, Sr, Ba), transition metals (Sc, Cr, Ni, Y, Zr, Nb, Hf and Ta), rare-earth elements (REE), actinides (Th, U) and p-block elements (F, S, Cl, Ge, Sn and Pb) have been prepared using the same procedure. Back-scattered electron (BSE) imaging accompanied by ion-microprobe (SHRIMP-RG) analysis confirms significant incorporation of selected trace-elements at structural sites. Regardless of some zonation, the large size of the crystals and broad regions of chemical homogeneity make these crystals useful as experimental starting material, and as matrix-matched trace-element standards for a variety of microbeam analytical techniques where amorphous titanite glass, heterogeneous natural titanite or a non-titanite standard may be less than satisfactory. Trace-element-doped synthetic crystals can also provide a convenient proxy for a better understanding of trace-element incorporation in natural titanite. Comparisons with igneous, authigenic and high-temperature metasomatic titanite are examined. The use of high-mass-resolution SIMS also demonstrates the analytical challenges inherent to any in situ mass-spectrometry-based analysis of titanite, owing to the production of difficult-to-resolve molecular interferences. These interferences are dominated by Ca-Ca, Ca-Ti and Ti-Ti dimers that are significant in the mass range of 80-100, affecting all isotopes of Sr and Zr, as well as 89Y and 93Nb. Methods do exist for the evaluation of interferences by these dimers and of polyatomic interferences on the LREE.

  13. Characterization of national food agency shrimp and plaice reference materials for trace elements and arsenic species by atomic and mass spectrometric techniques

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pedersen, Gitte Alsing; McLaren, J. W.

    1997-01-01

    , drying, milling and sieving to collect the fraction of particles less than 150 mu m in sizer In this fraction the trace elements were homogeneously distributed using a 400 mg sample intake for analysis, The total track element concentrations were determined by graphite furnace and cold vapour atomic...... mass spectrometry (MS/MS) for qualitative verification, Based on a rigorous statistical analysis of the analytical data using the DANREF software, it was decided to assign certified values for mercury, cadmium and arsenic in the NFA Shrimp, and mercury, selenium and arsenic in the NFA Plaice...

  14. A high-throughput solid-phase extraction microchip combined with inductively coupled plasma-mass spectrometry for rapid determination of trace heavy metals in natural water.

    Science.gov (United States)

    Shih, Tsung-Ting; Hsieh, Cheng-Chuan; Luo, Yu-Ting; Su, Yi-An; Chen, Ping-Hung; Chuang, Yu-Chen; Sun, Yuh-Chang

    2016-04-15

    Herein, a hyphenated system combining a high-throughput solid-phase extraction (htSPE) microchip with inductively coupled plasma-mass spectrometry (ICP-MS) for rapid determination of trace heavy metals was developed. Rather than performing multiple analyses in parallel for the enhancement of analytical throughput, we improved the processing speed for individual samples by increasing the operation flow rate during SPE procedures. To this end, an innovative device combining a micromixer and a multi-channeled extraction unit was designed. Furthermore, a programmable valve manifold was used to interface the developed microchip and ICP-MS instrumentation in order to fully automate the system, leading to a dramatic reduction in operation time and human error. Under the optimized operation conditions for the established system, detection limits of 1.64-42.54 ng L(-1) for the analyte ions were achieved. Validation procedures demonstrated that the developed method could be satisfactorily applied to the determination of trace heavy metals in natural water. Each analysis could be readily accomplished within just 186 s using the established system. This represents, to the best of our knowledge, an unprecedented speed for the analysis of trace heavy metal ions. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Trace elements in free-range hen eggs in the Campania region (Italy) analyzed by inductively coupled plasma mass spectrometry (ICP-MS).

    Science.gov (United States)

    Esposito, Mauro; Cavallo, Stefania; Chiaravalle, Eugenio; Miedico, Oto; Pellicanò, Roberta; Rosato, Guido; Sarnelli, Paolo; Baldi, Loredana

    2016-06-01

    Eggs from hens raised on rural or domestic farms are a good indicator of environmental contamination, as the hens are in close contact with the ground and the air and can therefore accumulate heavy metals and other toxic contaminants from the environment as well as from the diet. In this paper, we report the results of the determination of 19 trace elements (As, Be, Cd, Co, Cr, Cu, Hg, Mo, Mn, Ni, Pb, Sb, Se, Sn, Sr, Tl, U, V, Zn) in 39 hen egg samples collected from domestic poultry farms in the territory dubbed the "Land of fires" in the Campania region (Italy). This area is characterized by environmental problems caused by the illegal dumping of industrial or domestic waste in fields or by roadsides. In some cases, these wastes have been burned, thereby spreading persistent contaminants into the atmosphere. The content of trace elements in whole egg samples was determined by mass spectrometer after a microwave-assisted digestion procedure. Because European legislation does not indicate maximum values of these elements in this foodstuff, the results were compared with the content of trace elements reported in literature for eggs, in particular home-produced eggs, in various countries. In some cases (Cd, Cu, Ni, Mn), the content determined in this study was in line with those reported elsewhere, in other cases (Pb, Cr), lower values were found.

  16. Quantification of trace amounts of rare earth elements in high purity gadolinium oxide by sector field inductively coupled plasma mass spectrometry (ICP-MS)

    International Nuclear Information System (INIS)

    Pedreira, W.R.; Silva Queiroz, C.A. da; Abrao, A.; Pimentel, M.M.

    2004-01-01

    In recent years, rare earth elements (REEs) have received much attention in the fields of geochemistry and industry. Gadolinium oxide is used for many different high technology applications such as infrared absorbing automotive glass, petroleum cracking catalyst, gadolinium-yttrium garnets, microwave applications, and color TV tube phosphors. It can also be used in optical glass manufacturing and in the electronic industry. Rapid and accurate determinations of the rare earth elements are increasingly required as industrial demands expand. In general, the inductively coupled plasma mass spectrometry (ICP-MS) presents some advantages for trace element analysis, due to high sensitivity and resolution, when compared with other analytical techniques. In this work, sector field inductively coupled plasma mass spectrometry was used. Sixteen elements (Sc, Y, and 14 lanthanides) were determined selectively with the ICP-MS system using a concentration gradient method. The detection limits with the ICP-MS system were about 0.2-8 pg ml -1 . The recovery percentage ranged from 95 to 100% for different rare earth elements. The %R.S.D. of the methods varying between 1.5 and 2.5% for a set of five (n=5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two high pure gadolinium oxides samples (IPEN and JMC) was performed. IPEN's material is highly pure (>99.99%) and was successfully analyzed without spectral interference

  17. Direct determination of trace rare earth elements in ancient porcelain samples with slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Xiang Guoqiang; Jiang Zucheng; He Man; Hu Bin

    2005-01-01

    A method for the direct determination of trace rare earth elements in ancient porcelain samples by slurry sampling fluorinating electrothermal vaporization inductively coupled plasma mass spectrometry was developed with the use of polytetrafluoroethylene as fluorinating reagent. It was found that Si, as a main matrix element in ancient porcelain sample, could be mostly removed at the ashing temperature of 1200 deg. C without considerable losses of the analytes. However, the chemical composition of ancient porcelain sample is very complicated, which makes the influences resulting from other matrix elements not be ignored. Therefore, the matrix effect of ancient porcelain sample was also investigated, and it was found that the matrix effect is obvious when the matrix concentration was larger than 0.8 g l -1 . The study results of particle size effect indicated that when the sample particle size was less than 0.057 mm, the particle size effect is negligible. Under the optimized operation conditions, the detection limits for rare earth elements by fluorinating electrothermal vaporization inductively coupled plasma mass spectrometry were 0.7 ng g -1 (Eu)-33.3 ng g -1 (Nd) with the precisions of 4.1% (Yb)-10% (La) (c = 1 μg l -1 , n = 9). The proposed method was used to directly determine the trace rare earth elements in ancient porcelain samples produced in different dynasty (Sui, Ming and Qing), and the analytical results are satisfactory

  18. Selected ion flow tube mass spectrometry for on-line trace gas analysis in biology and medicine

    Czech Academy of Sciences Publication Activity Database

    Španěl, Patrik; Smith, D.

    2007-01-01

    Roč. 13, č. 1 (2007), s. 77-82 ISSN 1469-0667 R&D Projects: GA ČR GA202/06/0776 Institutional research plan: CEZ:AV0Z40400503 Keywords : selected ion flow tube mass spectroscopy (SIFT-MS) * breath analysis * breath metabolities * flowing afterglow mass spectrometry (FA-MS) Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.198, year: 2007

  19. Cadmium (II) imprinted 3-mercaptopropyltrimethoxysilane coated stir bar for selective extraction of trace cadmium from environmental water samples followed by inductively coupled plasma mass spectrometry detection

    International Nuclear Information System (INIS)

    Zhang Nan; Hu Bin

    2012-01-01

    Graphical abstract: Ion imprinted 3-mercaptopropyltrimethoxysilane (MPTS) coated stir bar for selective extraction of trace Cd(II). Highlights: ► Ion imprinted polymers were proposed as the coating for SBSE for the first time. ► Cd(II) imprinted MPTS-silica coating was prepared by a double-imprinting concept. ► A novel method of SBSE–ICP-MS was developed for the determination of Cd in waters. ► This method is rapid, selective, sensitive and applicable for determining trace Cd(II) in waters. - Abstract: Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol–gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5 μg and 0.8 μg bar −1 . The detection limit (3σ) based on three times standard deviations of the method blanks by 7 replicates was 4.40 ng L −1 and the relative standard deviation (RSD) was 3.38% (c = 1 μg L −1 , n = 7). The proposed method was successfully applied for the

  20. Cadmium (II) imprinted 3-mercaptopropyltrimethoxysilane coated stir bar for selective extraction of trace cadmium from environmental water samples followed by inductively coupled plasma mass spectrometry detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Nan [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China); Hu Bin, E-mail: binhu@whu.edu.cn [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China)

    2012-04-20

    Graphical abstract: Ion imprinted 3-mercaptopropyltrimethoxysilane (MPTS) coated stir bar for selective extraction of trace Cd(II). Highlights: Black-Right-Pointing-Pointer Ion imprinted polymers were proposed as the coating for SBSE for the first time. Black-Right-Pointing-Pointer Cd(II) imprinted MPTS-silica coating was prepared by a double-imprinting concept. Black-Right-Pointing-Pointer A novel method of SBSE-ICP-MS was developed for the determination of Cd in waters. Black-Right-Pointing-Pointer This method is rapid, selective, sensitive and applicable for determining trace Cd(II) in waters. - Abstract: Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol-gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5 {mu}g and 0.8 {mu}g bar{sup -1}. The detection limit (3{sigma}) based on three times standard deviations of the method blanks by 7 replicates was 4.40 ng L{sup -1} and the relative standard

  1. Ultra-trace determination of plutonium in marine samples using multi-collector inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Lindahl, Patric; Keith-Roach, Miranda; Worsfold, Paul; Choi, Min-Seok; Shin, Hyung-Seon; Lee, Sang-Hoon

    2010-06-25

    Sources of plutonium isotopes to the marine environment are well defined, both spatially and temporally, which makes Pu a potential tracer for oceanic processes. This paper presents the selection, optimisation and validation of a sample preparation method for the ultra-trace determination of Pu isotopes ((240)Pu and (239)Pu) in marine samples by multi-collector (MC) ICP-MS. The method was optimised for the removal of the interference from (238)U and the chemical recovery of Pu. Comparison of various separation strategies using AG1-X8, TEVA, TRU, and UTEVA resins to determine Pu in marine calcium carbonate samples is reported. A combination of anion-exchange (AG1-X8) and extraction chromatography (UTEVA/TRU) was the most suitable, with a radiochemical Pu yield of 87+/-5% and a U decontamination factor of 1.2 x 10(4). Validation of the method was accomplished by determining Pu in various IAEA certified marine reference materials. The estimated MC-ICP-MS instrumental limit of detection for (239)Pu and (240)Pu was 0.02 fg mL(-1), with an absolute limit of quantification of 0.11 fg. The proposed method allows the determination of ultra-trace Pu, at femtogram levels, in small size marine samples (e.g., 0.6-2.0 g coral or 15-20 L seawater). Finally, the analytical method was applied to determining historical records of the Pu signature in coral samples from the tropical Northwest Pacific and (239+240)Pu concentrations and (240)Pu/(239)Pu atom ratios in seawater samples as part of the 2008 GEOTRACES intercalibration exercise. Copyright 2010 Elsevier B.V. All rights reserved.

  2. Ultra-trace determination of plutonium in marine samples using multi-collector inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, Patric, E-mail: patriclindahl@yahoo.com [Marine Environment Research Department, Korea Ocean Research and Development Institute, 1270 Sadong, Ansan 426-744 (Korea, Republic of); School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL48AA (United Kingdom); Keith-Roach, Miranda; Worsfold, Paul [School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL48AA (United Kingdom); Choi, Min-Seok; Shin, Hyung-Seon [Division of Earth and Environmental Science, Korea Basic Science Institute, 113 Gwahangno, Yusung-gu, Daejon 305-333 (Korea, Republic of); Lee, Sang-Hoon [Marine Geology and Geophysics Laboratory, Korea Ocean Research and Development Institute, 1270 Sadong, Ansan 426-744 (Korea, Republic of)

    2010-06-25

    Sources of plutonium isotopes to the marine environment are well defined, both spatially and temporally, which makes Pu a potential tracer for oceanic processes. This paper presents the selection, optimisation and validation of a sample preparation method for the ultra-trace determination of Pu isotopes ({sup 240}Pu and {sup 239}Pu) in marine samples by multi-collector (MC) ICP-MS. The method was optimised for the removal of the interference from {sup 238}U and the chemical recovery of Pu. Comparison of various separation strategies using AG1-X8, TEVA, TRU, and UTEVA resins to determine Pu in marine calcium carbonate samples is reported. A combination of anion-exchange (AG1-X8) and extraction chromatography (UTEVA/TRU) was the most suitable, with a radiochemical Pu yield of 87 {+-} 5% and a U decontamination factor of 1.2 x 10{sup 4}. Validation of the method was accomplished by determining Pu in various IAEA certified marine reference materials. The estimated MC-ICP-MS instrumental limit of detection for {sup 239}Pu and {sup 240}Pu was 0.02 fg mL{sup -1}, with an absolute limit of quantification of 0.11 fg. The proposed method allows the determination of ultra-trace Pu, at femtogram levels, in small size marine samples (e.g., 0.6-2.0 g coral or 15-20 L seawater). Finally, the analytical method was applied to determining historical records of the Pu signature in coral samples from the tropical Northwest Pacific and {sup 239+240}Pu concentrations and {sup 240}Pu/{sup 239}Pu atom ratios in seawater samples as part of the 2008 GEOTRACES intercalibration exercise.

  3. Ultra-trace determination of plutonium in marine samples using multi-collector inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Lindahl, Patric; Keith-Roach, Miranda; Worsfold, Paul; Choi, Min-Seok; Shin, Hyung-Seon; Lee, Sang-Hoon

    2010-01-01

    Sources of plutonium isotopes to the marine environment are well defined, both spatially and temporally, which makes Pu a potential tracer for oceanic processes. This paper presents the selection, optimisation and validation of a sample preparation method for the ultra-trace determination of Pu isotopes ( 240 Pu and 239 Pu) in marine samples by multi-collector (MC) ICP-MS. The method was optimised for the removal of the interference from 238 U and the chemical recovery of Pu. Comparison of various separation strategies using AG1-X8, TEVA, TRU, and UTEVA resins to determine Pu in marine calcium carbonate samples is reported. A combination of anion-exchange (AG1-X8) and extraction chromatography (UTEVA/TRU) was the most suitable, with a radiochemical Pu yield of 87 ± 5% and a U decontamination factor of 1.2 x 10 4 . Validation of the method was accomplished by determining Pu in various IAEA certified marine reference materials. The estimated MC-ICP-MS instrumental limit of detection for 239 Pu and 240 Pu was 0.02 fg mL -1 , with an absolute limit of quantification of 0.11 fg. The proposed method allows the determination of ultra-trace Pu, at femtogram levels, in small size marine samples (e.g., 0.6-2.0 g coral or 15-20 L seawater). Finally, the analytical method was applied to determining historical records of the Pu signature in coral samples from the tropical Northwest Pacific and 239+240 Pu concentrations and 240 Pu/ 239 Pu atom ratios in seawater samples as part of the 2008 GEOTRACES intercalibration exercise.

  4. Microwave synthesis of gibberellin acid 3 magnetic molecularly imprinted polymer beads for the trace analysis of gibberellin acids in plant samples by liquid chromatography-mass spectrometry detection.

    Science.gov (United States)

    Zhang, Zhuomin; Tan, Wei; Hu, Yuling; Li, Gongke; Zan, Song

    2012-02-21

    In this study, novel GA3 magnetic molecularly imprinted polymer (mag-MIP) beads were synthesized by a microwave irradiation method, and the beads were applied for the trace analysis of gibberellin acids (GAs) in plant samples including rice and cucumber coupled with high performance liquid chromatography-mass spectrometry (HPLC-MS). The microwave synthetic procedure was optimized in detail. In particular, the interaction between GA3 and functional monomers was further studied for the selection of the optimal functional monomers during synthesis. It can be seen that the interaction between GA3 and acrylamide (AM) finally selected was stronger than that between GA3 and other functional monomers. GA3 mag-MIP beads were characterized by a series of physical tests. GA3 mag-MIP beads had a porous and homogeneous surface morphology with stable chemical, thermal and magnetic properties. Moreover, GA3 mag-MIP beads demonstrated selective and specific absorption behavior for the target compounds during unsaturated extraction, which resulted in a higher extraction capacity (∼708.4 pmol for GA3) and selectivity than GA3 mag-non-imprinted polymer beads. Finally, an analytical method of GA3 mag-AM-MIP bead extraction coupled with HPLC-MS detection was established and applied for the determination of trace GA1, GA3, GA4 and GA7 in rice and cucumber samples. It was satisfactory that GA4 could be actually found to be 121.5 ± 1.4 μg kg(-1) in real rice samples by this novel analytical method. The recoveries of spiked rice and cucumber samples were found to be 76.0-109.1% and 79.9-93.6% with RSDs of 2.8-8.8% and 3.1-7.7% (n = 3), respectively. The proposed method is efficient and applicable for the trace analysis of GAs in complicated plant samples.

  5. Trace analysis of actinides in the environment using resonance ionization mass spectrometry; Spurenanalyse von Aktiniden in der Umwelt mittels Resonanzionisations-Massenspektrometrie

    Energy Technology Data Exchange (ETDEWEB)

    Raeder, Sebastian

    2011-04-12

    In this work the resonant ionization of neutral atoms using laser radiation was applied and optimized for ultra-trace analysis of the actinides thorium, uranium, neptunium and plutonium. The sensitive detection of these actinides is a challange for the monitoring and quantification of radioactive releases from nuclear facilities. Using resonance ionization spectroscopy combined with a newly developed quadrupole-mass-spectrometer, numerous energy levels in the atomic structure of these actinides could be identified. With this knowledge efficient excitation schemes for the mentioned actinides could be identified and characterised. The applied in-source-ionization ensures for a high detection efficiency due to the good overlap of laser radiation with the atomic beam and allows therefore for a low sample consumption which is required for the analysis of radio nuclides. The selective excitation processes in the resonant ionization method supresses unwanted contaminations and was optimized for analytical detection of ultra-trace amounts in environmental samples as well as for determination of isotopic compositions. The efficient in-source-ionization combined with high power pulsed laser radiation allows for detections efficiency up to 1%. For plutonium detection limits in the range of 10{sup 4}-10{sup 5} atoms could be demonstrated for synthetic samples as well as for first environmental samples. The usage of narrow bandwidth continuous wave lasers in combination with a transversal overlap of the laser radiation and the free propagating atomic beam enable for resolving individual isotopic shifts of the resonant transitions. This results in a high selectivity against dominant neighboring isotopes but with a significant loss in detection efficiency. For the ultra-trace isotope {sup 236}U a detection limit down to 10{sup -9} for the isotope ratio N ({sup 236}U)/N ({sup 238}U) could be determined.

  6. The chemical speciation and analysis of trace elements in sediment with Neutron Activation Analytical method(NAA) and atomic mass spectrometry

    International Nuclear Information System (INIS)

    Nam, Sang-Ho; Kim, Jae-Jin; Chung, Yong-Sam; Kim, Sun-Ha

    2003-01-01

    In this research, first of all, the analytical methods for the determination of major elements in sediment have been developed with ICP-MS (Inductively Coupled Plasma Mass Spectrometry). The analytical results of major elements (Al, Ca, K, Fe, Mg) with Cool ICP-MS were much better than those with normal ICP-MS. The analytical results were compared with those of NAA (Neutron Activation Analysis). NAA were a little superior to ICP-MS for the determination of major elements in sediment as a non-destructive trace analytical trace analytical method. The analytical methods for the determination of minor elements (Cr, Ce, U, Co, Pb, As, Se) have been also developed with ICP-MS. The analytical results by standard calibration curve with ICP-MS were not accurate due to the matrix interferences. Thus, the internal standard method was applied, then the analytical results for minor elements with ICP-MS were greatly improved. The analytical results obtained by ICP-MS were compared with those obtained by NAA. It showed that the two analytical methods have great capabilities for the determination of minor elements in sediments. Accordingly, the NAA will plan an important role in analysis of environment sample with complex matrix. ICP-MS also will play an important role because it has a great capability for the determination of Pb that could not be determined by NAA

  7. Trace analysis of icariin in human serum with dansyl chloride derivatization after oral administration of Epimedium decoction by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Gong, Yinhan; Yip, See Chung; Thamarai, Sennappan Kanagamani; Zhang, Jie; Lee, Hian Kee; Yong, E L

    2007-12-15

    Epimedium herbs are a type of complex traditional Chinese medicine (TCM) with high estrogenic bioactivity. The Epimedium herbal decoction mixture contains many compounds including icariin that can exert potent effects on numerous physiological processes related to human health. An ultrasensitive liquid chromatography tandem mass spectrometric (LC-MS/MS) method has been developed to determine trace levels of icariin in human serum with dansyl chloride derivatization after oral administration of the Epimedium herbal decoctions. The dansyl-icariin showed an intense protonated molecular ion at m/z 910. The collision-induced dissociation of this ion formed a distinctive product at m/z 764, corresponding to a characteristic removal of a rhamnose sugar moiety of icariin. The selected reaction monitoring, based on the m/z 910-->764 transition, was highly specific and ultrasenstive for icariin in human serum samples. The lower limit of quantitation was 10 pg/mL icariin spiked into blank serum. The ranges of coefficients of variation for interday assays and intraday assays were 0-15.0% and 1.1-17.5%, respectively, for a wide linear range from 10 pg/mL to 4 ng/mL. This method was successfully applied to measure trace levels of icariin in a human serum after oral administration of Epimedium decoction within 48 h for the first time.

  8. Comparison of sample digestion techniques for the determination of trace and residual catalyst metal content in single-wall carbon nanotubes by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Grinberg, Patricia, E-mail: patricia.grinberg@nrc.ca [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Sturgeon, Ralph E. [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Diehl, Liange de O.; Bizzi, Cezar A. [Measurement Science and Standards, National Research Council Canada, Ottawa (Canada); Chemistry Department, Universidade Federal de Santa Maria, Santa Maria (Brazil); Flores, Erico M.M. [Chemistry Department, Universidade Federal de Santa Maria, Santa Maria (Brazil)

    2015-03-01

    A single-wall carbon nanotube material produced by laser ablation of renewable biochar in the presence of Ni and Co catalyst was characterized for residual catalyst (Co and Ni) as well as trace metal impurity content (Fe, Mo, Cr, Pb and Hg) by isotope dilution ICP-MS following sample digestion. Several matrix destruction procedures were evaluated, including a multi-step microwave-assisted acid digestion, dry ashing at 450 °C and microwave-induced combustion with oxygen. Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements. Although laborious to execute, the multi-step microwave-assisted acid digestion proved to be most reliable for recovery of the majority of the analytes, although content of Cr remained biased low for each approach, likely due to its presence as refractory carbide. - Highlights: • Determination of trace and residual catalyst metal content in Single-Wall Carbon Nanotubes by Inductively Coupled Plasma Mass Spectrometry. • Comparative study of digestion methodology combined with high precision isotope dilution ICP-MS for quantitation of elements of toxicologic relevance. • Results were benchmarked against those derived from neutron activation analysis and also supported by solid sampling continuum source GF-AAS for several of the elements.

  9. Direct detection of benzene, toluene, and ethylbenzene at trace levels in ambient air by atmospheric pressure chemical ionization using a handheld mass spectrometer.

    Science.gov (United States)

    Huang, Guangming; Gao, Liang; Duncan, Jason; Harper, Jason D; Sanders, Nathaniel L; Ouyang, Zheng; Cooks, R Graham

    2010-01-01

    The capabilities of a portable mass spectrometer for real-time monitoring of trace levels of benzene, toluene, and ethylbenzene in air are illustrated. An atmospheric pressure interface was built to implement atmospheric pressure chemical ionization for direct analysis of gas-phase samples on a previously described miniature mass spectrometer (Gao et al. Anal. Chem.2006, 78, 5994-6002). Linear dynamic ranges, limits of detection and other analytical figures of merit were evaluated: for benzene, a limit of detection of 0.2 parts-per-billion was achieved for air samples without any sample preconcentration. The corresponding limits of detection for toluene and ethylbenzene were 0.5 parts-per-billion and 0.7 parts-per-billion, respectively. These detection limits are well below the compounds' permissible exposure levels, even in the presence of added complex mixtures of organics at levels exceeding the parts-per-million level. The linear dynamic ranges of benzene, toluene, and ethylbenzene are limited to approximately two orders of magnitude by saturation of the detection electronics. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  10. Note: Possibilities of detecting the trace-level erosion products from an electric propulsion hollow cathode plasma source by the method of time-of-flight mass spectrometry

    Science.gov (United States)

    Ning, Zhong-Xi; Zhang, Hai-Guang; Zhu, Xi-Ming; Jiang, Bin-Hao; Zhou, Zhong-Yue; Yu, Da-Ren; An, Bing-Jian; Wang, Yan-Fei

    2018-02-01

    A hollow cathode produces electrons which neutralize ions from electric propulsion thrusters. After hundreds to thousands of hours of operation in space, the cathode materials can be significantly eroded due to ion bombardment. As a result, the electric propulsion system performance will be obviously changed or even fail. In this work, the erosion products from a LaB6 hollow cathode (widely used presently in electric propulsion systems) are studied by using a specific detection system, which consists of a molecular beam sampler and a time-of-flight mass spectrometer. This system measures trace-level-concentration (10-6-10-3) products. Boron (B), tantalum (Ta), and tungsten (W)—originating from the emitter, keeper, and orifice of the hollow cathode—are measured. It is found that the erosion rate is significantly influenced by the gas flow rate to the cathode.

  11. Development and method of use of a mass spectrometric isotope dilution analysis within the use of negative thermoionisation for determination of boron traces

    International Nuclear Information System (INIS)

    Zeininger, H.

    1984-01-01

    A mass spectrometric trace boron determination using negative thermionisation was developed. It is based on the determination of the ratio of BO 2 - isotopes ( 10 B and 11 B). A high stability and a constant intensity at a given temperature of the BO 2 - ion currents allow for a computer controlled measurement with a programmed heating. The reproducibility lies at around 0,004-0,08%. The boron determination using Mels potentiometry with a BF 4 - -ion selective electrode was used as an analytical comparison method. The MS-IDA was first used on metal samples, such as Al, Zr, and steel. Later on the boron in reagents, biological material (milk powder, spinach, water plants) and water were determined. For this material-dependent hydrolysation and separation procedures were worked out. The MS-IDA in comparison to all other analytical methods used by other collaborators offers the greatest accuracy. (RB) [de

  12. Mass loads of dissolved and particulate mercury and other trace elements in the Mt. Amiata mining district, Southern Tuscany (Italy)

    Science.gov (United States)

    Rimondi, V.; Costagliola, P.; Gray, J.E.; Lattanzi, P.; Nannucci, M.; Paolieri, M.; Salvadori, A.

    2014-01-01

    Total dissolved and particulate mercury (Hg), arsenic (As), and antimony (Sb) mass loads were estimated in different seasons (March and September 2011 and March 2012) in the Paglia River basin (PRB) (central Italy). The Paglia River drains the Mt. Amiata Hg district, one of the largest Hg-rich regions worldwide. Quantification of Hg, As, and Sb mass loads in this watershed allowed (1) identification of the contamination sources, (2) evaluation of the effects of Hg on the environment, and (3) determination of processes affecting Hg transport. The dominant source of Hg in the Paglia River is runoff from Hg mines in the Mt. Amiata region. The maximum Hg mass load was found to be related to runoff from the inactive Abbadia San Salvatore Mine (ASSM), and up to 30 g day−1 of Hg, dominantly in the particulate form, was transported both in high and low flow conditions in 2011. In addition, enrichment factors (EFs) calculated for suspended particulate matter (SPM) were similar in different seasons indicating that water discharge controls the quantities of Hg transported in the PRB, and considerable Hg was transported in all seasons studied. Overall, as much as 11 kg of Hg are discharged annually in the PRB and this Hg is transported downstream to the Tiber River, and eventually to the Mediterranean Sea. Similar to Hg, maximum mass loads for As and Sb were found in March 2011, when as much as 190 g day−1 each of As and Sb were measured from sites downstream from the ASSM. Therefore, the Paglia River represents a significant source of Hg, Sb, and As to the Mediterranean Sea.

  13. Trace-Level Screening of Chemicals Related to Clandestine Desomorphine Production with Ambient Sampling, Portable Mass Spectrometry

    OpenAIRE

    Hall, Seth E.; O’Leary, Adam E.; Lawton, Zachary E.; Bruno, Alessandra M.; Mulligan, Christopher C.

    2017-01-01

    Desomorphine is a semisynthetic opioid that is responsible for the psychoactive effects of a dangerous homemade injectable mixture that goes by street name “Krokodil.” Desorption electrospray ionization (DESI) and paper spray ionization (PSI) are implemented on a portable mass spectrometer for the direct analysis of desomorphine and precursor reagent codeine from multiple substrates of potential relevance to clandestine drug laboratory synthesis and paraphernalia seizure. Minimal sample prepa...

  14. Detection of trace organics in Mars analog samples containing perchlorate by laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Li, Xiang; Danell, Ryan M; Brinckerhoff, William B; Pinnick, Veronica T; van Amerom, Friso; Arevalo, Ricardo D; Getty, Stephanie A; Mahaffy, Paul R; Steininger, Harald; Goesmann, Fred

    2015-02-01

    Evidence from recent Mars missions indicates the presence of perchlorate salts up to 1 wt % level in the near-surface materials. Mixed perchlorates and other oxychlorine species may complicate the detection of organic molecules in bulk martian samples when using pyrolysis techniques. To address this analytical challenge, we report here results of laboratory measurements with laser desorption mass spectrometry, including analyses performed on both commercial and Mars Organic Molecule Analyzer (MOMA) breadboard instruments. We demonstrate that the detection of nonvolatile organics in selected spiked mineral-matrix materials by laser desorption/ionization (LDI) mass spectrometry is not inhibited by the presence of up to 1 wt % perchlorate salt. The organics in the sample are not significantly degraded or combusted in the LDI process, and the parent molecular ion is retained in the mass spectrum. The LDI technique provides distinct potential benefits for the detection of organics in situ on the martian surface and has the potential to aid in the search for signs of life on Mars.

  15. Trace level liquid chromatography tandem mass spectrometry quantification of the mutagenic impurity 2-hydroxypyridine N-oxide as its dansyl derivative.

    Science.gov (United States)

    Ding, Wei; Huang, Yande; Miller, Scott A; Bolgar, Mark S

    2015-03-20

    A derivatization LC-MS/MS method was developed and qualified for the trace level quantification of 2-hydroxypyridine N-oxide (HOPO). HOPO is a coupling reagent used in the syntheses of active pharmaceutical ingredients (APIs) to form amide bonds. HOPO was recently confirmed to generate a positive response in a GLP Ames bacterial-reverse-mutation test, classifying it as a mutagenic impurity and as such requiring its control in APIs to the threshold of toxicological concern (TTC). The derivatization reagent 5-dimethylamino-1-naphthalenesulfonyl chloride (dansyl chloride) was used in a basic solution to convert HOPO into the corresponding dansyl-derivative. The derivative was separated from different APIs and reagents by liquid chromatography. The detection of the HOPO dansyl-derivative was achieved by mass spectrometry in selected reaction monitoring (SRM) mode. The LC-MS/MS method had a reporting limit of 0.1ng/mL HOPO, which corresponds to 0.1ppm HOPO relative to an API at 1mg/mL, and a linearity range of 0.1-25ng/mL HOPO analyte. Recoveries of HOPO standards spiked into three different API matrices at 0.2, 1.2, and 20ppm levels were all within 90-100%. An SRM-based confirmatory methodology using the ratios of two fragment ions at three CID energies was developed to verify the identity of HOPO when present at ≥0.6ppm. This identity confirmation can be employed to prevent potential false positive detection of mutagenic impurities at trace level. It can be broadly applicable for the confirmation of analytes when the analytes generate at least two major fragments in tandem mass spectrometry experiments. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of trace amount of lanthanides and yttrium in soil with polytetrafluroethylene emulsion as a chemical modifier

    International Nuclear Information System (INIS)

    He Man; Hu, Bin; Jiang Zucheng

    2005-01-01

    A method of electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the determination of trace lanthanides and yttrium in soil samples with a polytetrafluorethylene (PTFE) emulsion as chemical modifier to promote the vaporization of the analytes from the graphite furnace was developed in this paper. The analytical characteristics, spectral interference and matrix effect of the analytical method were evaluated and critically compared with those of pneumatic nebulization inductively coupled plasma mass spectrometry (PN-ICP-MS). Under the optimized operation conditions, the relative detection limits of lanthanides (La-Lu) and yttrium for ETV-ICP-MS and PN-ICP-MS were 0.4-20 ng l -1 and 1.0-21 ng l -1 , respectively, the absolute detection limits for ETV-ICP-MS were 4-200 fg, which were improved by 1-2 orders of magnitude compared with PN-ICP-MS. While the analytical precision of ETV-ICP-MS is worse than that of PN-ICP-MS, with the R.S.D.s (%) of 4.1-10% for the former and 2.9-7.8% for the latter. Regarding to the matrix effect, both conventional method and stepwise dilution method were employed to observe the effect of matrix and the very similar results were obtained. It was found that the highest tolerance concentration of the matrix is 1000 mg l -1 and 800 mg l -1 for ETV-ICP-MS and PN-ICP-MS, respectively. To assess the accuracy, the proposed method was applied to the determination of trace lanthanides and yttrium in three different soil standard reference materials and one soil sample, and the determined values are in good agreement with the certified values or reference values

  17. Cyclic organic peroxides identification and trace analysis by Raman microscopy and open-air chemical ionization mass spectrometry

    Science.gov (United States)

    Pena-Quevedo, Alvaro Javier

    The persistent use of cyclic organic peroxides in explosive devices has increased the interest in study these compounds. Development of methodologies for the detection of triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) has become an urgent priority. However, differences in physical properties between cyclic organic peroxides make difficult the development of a general method for peroxide analysis and detection. Following this urgency, the first general technique for the analysis of any peroxide, regarding its structural differences is reported. Characterization and detection of TATP and HMTD was performed using an Open-Air Chemical Ionization High-Resolution Time-of-Flight Mass Spectrometer. The first spectrometric analysis for tetramethylene diperoxide dicarbamide (TMDD) and other nitrogen based peroxides using Raman Microscopy and Mass Spectrometry is reported. Analysis of cyclic peroxides by GC-MS was also conducted to compare results with OACI-HRTOF data. In the OACI mass spectrum, HMTD showed a clear signal at m/z 209 MH + and a small adduct peak at m/z 226 [M+NH4]+ that allowed its detection in commercial standard solutions and lab made standards. TMDD presented a molecular peak of m/z 237 MH+ and an adduct peak of m/z 254 [M+NH4]+. TATP showed a single peak at m/z 240 [M+NH4]+, while the peak of m/z 223 or 222 was completely absent. This evidence suggests that triperoxides are stabilized by the ammonium ion. TATP samples with deuterium enrichment were analyzed to compare results that could differentiate from HMTD. Raman microscopy was used as a complementary characterization method and was an essential tool for cyclic peroxides identification, particularly for those which could not be extensively purified. All samples were characterized by Raman spectroscopy to confirm the Mass Spectrometry results. Peroxide O-O vibrations were observed around 750-970 cm-1. D18-TATP studies had identified ketone triperoxide nu(O-O) vibration around

  18. Characterization of key aerosol, trace gas and meteorological properties and particle formation and growth processes dependent on air mass origins in coastal Southern Spain

    Science.gov (United States)

    Diesch, J.; Drewnick, F.; Sinha, V.; Williams, J.; Borrmann, S.

    2011-12-01

    The chemical composition and concentration of aerosols at a certain site can vary depending on season, the air mass source region and distance from sources. Regardless of the environment, new particle formation (NPF) events are one of the major sources for ultrafine particles which are potentially hazardous to human health. Grown particles are optically active and efficient CCN resulting in important implications for visibility and climate (Zhang et al., 2004). The study presented here is intended to provide information about various aspects of continental, urban and marine air masses reflected by wind patterns of the air arriving at the measurement site. Additionally we will be focusing on NPF events associated with different types of air masses affecting their emergence and temporal evolution. Measurements of the ambient aerosol, various trace gases and meteorological parameters were performed within the framework of the DOMINO (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) project. The field campaign took place from mid-November to mid-December 2008 at the atmospheric research station "El Arenosillo" located at the interface between a natural park, industrial cities (Huelva, Seville) and the Atlantic Ocean. Number and mass as well as PAH and black carbon concentrations were measured in PM1 and size distribution instruments covered the size range 6 nm up to 32 μm. The chemical composition of the non-refractory submicron aerosol was measured by means of an Aerosol Mass Spectrometer (AMS). In order to evaluate the characteristics of different air masses linking local and regional sources as well as NPF processes, characteristic air mass types were classified dependent on backwards trajectory pathways and local meteorology. Large nuclei mode concentrations in the number size distribution were found within continental and urban influenced air mass types due to frequently occurring NPF events. Exploring individual production and sink variables, sulfuric

  19. Trace isotope analysis using resonance ionization mass spectrometry based on isotope selection with doppler shift of laser ablated atoms

    International Nuclear Information System (INIS)

    Higuchi, Yuki; Watanabe, Kenichi; Kawarabayashi, Jun; Iguchi, Tetsuo

    2005-01-01

    We have proposed a novel isotope selective Resonance Ionization Mass Spectroscopy (RIMS) concept, which can avoid the Doppler broadening on solid sample direct measurement based on laser ablation technique. We have succeeded in experimentally demonstrating the principle of our RIMS concept. Through comparison between the simulated and experimental results, we have validated the simulation model. It would be concluded from these results that we could achieve the isotope selectivity defined as the ratio of 41 Ca to 40 Ca sensitivity to be 4.5x10 10 by adopting the multi-step excitation scheme in the present method. As future works, we will try to experimentally perform the multi-step excitation scheme and improve the detection efficiency by modifying the ion extraction configuration. (author)

  20. Trace analysis of tiamulin in honey by liquid chromatography-diode array-electrospray ionization mass spectrometry detection.

    Science.gov (United States)

    Nozal, M J; Bernal, J L; Martín, M T; Jiménez, J J; Bernal, J; Higes, M

    2006-05-26

    A liquid chromatography with diode array or electrospray ionisation mass spectrometry detection (LC-DAD-ESI-MS) method for the determination of tiamulin residues in honey is presented. The procedure employs a solid-phase extraction (SPE) on polymeric cartridges for the isolation of tiamulin from honey samples diluted in aqueous solution of tartaric acid. Chromatographic separation of the tiamulin is performed, in isocratic mode, on a C18 column using methanol and ammonium carbonate 0.1% in water, in proportion (30:70, v/v). Average analyte recoveries were from 88 to 106% in replica sets of fortified honey samples. The LC-ESI-MS method detection limits differ from 0.5 microg kg(-1) for clear honeys to 1.2 microg kg(-1) for dark honeys. The developed method has been applied to the analysis of tiamulin residues in multifloral honey samples collected from veterinary treated beehives.

  1. Trace-Level Screening of Chemicals Related to Clandestine Desomorphine Production with Ambient Sampling, Portable Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Seth E. Hall

    2017-01-01

    Full Text Available Desomorphine is a semisynthetic opioid that is responsible for the psychoactive effects of a dangerous homemade injectable mixture that goes by street name “Krokodil.” Desorption electrospray ionization (DESI and paper spray ionization (PSI are implemented on a portable mass spectrometer for the direct analysis of desomorphine and precursor reagent codeine from multiple substrates of potential relevance to clandestine drug laboratory synthesis and paraphernalia seizure. Minimal sample preparation required for analysis and portability of the instrument suggest the potential for rapid, on-site analysis of evidence, a highly desired benefit for forensic science and law enforcement practitioners. Both DESI-MS and PSI-MS can generate spectra consistent with preceding data obtained using traditional ionization methods, while demonstrating detection limits in the low- to sub-ng levels.

  2. Analysis of trace levels of sulfonamide and tetracycline antimicrobials in groundwater and surface water using solid-phase extraction and liquid chromatography/mass spectrometry

    Science.gov (United States)

    Lindsey, M.E.; Meyer, M.; Thurman, E.M.

    2001-01-01

    A method has been developed for the trace analysis of two classes of antimicrobials consisting of six sulfonamides (SAs) and five tetracyclines (TCs), which commonly are used for veterinary purposes and agricultural feed additives and are suspected to leach into ground and surface water. The method used solid-phase extraction and liquid chromatography/mass spectrometry (LC/MS) with positive ion electrospray. The unique combination of a metal chelation agent (Na2EDTA) with a macroporous copolymer resulted in quantitative recoveries by solid-phase extraction (mean recovery, 98 ?? 12%) at submicrogram-per-liter concentrations. An ammonium formate/formic acid buffer with a methanol/water gradient was used to separate the antimicrobials and to optimize the signal intensity. Mass spectral fragmentation and ionization characteristics were determined for each class of compounds for unequivocal identification. For all SAs, a characteristic m/z 156 ion representing the sulfanilyl fragment was identified. TCs exhibited neutral losses of 17 amu resulting from the loss of ammonia and 35 amu from the subsequent loss of water. Unusual matrix effects were seen only for TCs in this first survey of groundwater and surface water samples from sites around the United States, requiring that TCs be quantitated using the method of standard additions.

  3. Ultra-trace determination of Persistent Organic Pollutants in Arctic ice using stir bar sorptive extraction and gas chromatography coupled to mass spectrometry.

    Science.gov (United States)

    Lacorte, S; Quintana, J; Tauler, R; Ventura, F; Tovar-Sánchez, A; Duarte, C M

    2009-12-04

    This study presents the optimization and application of an analytical method based on the use of stir bar sorptive extraction (SBSE) gas chromatography coupled to mass spectrometry (GC-MS) for the ultra-trace analysis of POPs (Persistent Organic Pollutants) in Arctic ice. In a first step, the mass-spectrometry conditions were optimized to quantify 48 compounds (polycyclic aromatic hydrocarbons, brominated diphenyl ethers, chlorinated biphenyls, and organochlorinated pesticides) at the low pg/L level. In a second step, the performance of this analytical method was evaluated to determine POPs in Arctic cores collected during an oceanographic campaign. Using a calibration range from 1 to 1800 pg/L and by adjusting acquisition parameters, limits of detection at the 0.1-99 and 102-891 pg/L for organohalogenated compounds and polycyclic aromatic hydrocarbons, respectively, were obtained by extracting 200 mL of unfiltered ice water. alpha-hexachlorocyclohexane, DDTs, chlorinated biphenyl congeners 28, 101 and 118 and brominated diphenyl ethers congeners 47 and 99 were detected in ice cores at levels between 0.5 to 258 pg/L. We emphasise the advantages and disadvantages of in situ SBSE in comparison with traditional extraction techniques used to analyze POPs in ice.

  4. Mass

    International Nuclear Information System (INIS)

    Quigg, Chris

    2007-01-01

    In the classical physics we inherited from Isaac Newton, mass does not arise, it simply is. The mass of a classical object is the sum of the masses of its parts. Albert Einstein showed that the mass of a body is a measure of its energy content, inviting us to consider the origins of mass. The protons we accelerate at Fermilab are prime examples of Einsteinian matter: nearly all of their mass arises from stored energy. Missing mass led to the discovery of the noble gases, and a new form of missing mass leads us to the notion of dark matter. Starting with a brief guided tour of the meanings of mass, the colloquium will explore the multiple origins of mass. We will see how far we have come toward understanding mass, and survey the issues that guide our research today.

  5. Trace determination of 13 haloacetamides in drinking water using liquid chromatography triple quadrupole mass spectrometry with atmospheric pressure chemical ionization.

    Science.gov (United States)

    Chu, Wenhai; Gao, Naiyun; Yin, Daqiang; Krasner, Stuart W; Templeton, Michael R

    2012-04-27

    The haloacetamides (HAcAms) are disinfection by-products (DBPs) in drinking water which are currently receiving increased scientific attention due to their elevated toxicity relative to regulated disinfection by-products. A simultaneous determination method of 13 HAcAms, combining solid-phase extraction (SPE) enrichment, liquid chromatographic (LC) separation, and triple quadrupole mass spectrometry (tqMS) detection with atmospheric pressure chemical ionization (APCI) using selective reaction monitoring in positive mode, was developed to measure HAcAms, including chlorinated, brominated, and iodinated analogs. Ammonium chloride and Oasis HLB were selected as the dechlorinating reagent and polymeric SPE sorbent of HAcAm samples. The used tqMS apparatus showed higher sensitivity for the studied HAcAms in the APCI mode than electrospray ionization. 13 HAcAms were separated by LC in 9.0 min, and the detection limits ranged from 7.6 to 19.7 ng/L. The SPE-LC/tqMS method was successfully applied to quantify 13 HAcAms in drinking water samples for the first time, and first indentified tribromoacetamide and chloroiodoacetamide as DBPs in drinking water. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Analysis of Trace Quaternary Ammonium Compounds (QACs) in Vegetables Using Ultrasonic-Assisted Extraction and Gas Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Xiang, Lei; Wang, Xiong-Ke; Li, Yan-Wen; Huang, Xian-Pei; Wu, Xiao-Lian; Zhao, Hai-Ming; Li, Hui; Cai, Quan-Ying; Mo, Ce-Hui

    2015-08-05

    A reliable, sensitive, and cost-effective method was developed for determining three quaternary ammonium compounds (QACs) including dodecyltrimethylammonium chloride, cetyltrimethylammonium chloride, and didodecyldimethylammonium chloride in various vegetables using ultrasonic-assisted extraction and gas chromatography-mass spectrometry. The variety and acidity of extraction solvents, extraction times, and cleanup efficiency of sorbents were estimated to obtain an optimized procedure for extraction of the QACs in nine vegetable matrices. Excellent linearities (R(2) > 0.992) were obtained for the analytes in the nine matrices. The limits of detection and quantitation were 0.7-6.0 and 2.3-20.0 μg/kg (dry weight, dw) in various matrices, respectively. The recoveries in the nine matrices ranged from 70.5% to 108.0% with relative standard deviations below 18.0%. The developed method was applied to determine the QACs in 27 vegetable samples collected from Guangzhou in southern China, showing very high detection frequency with a concentration of 23-180 μg/kg (dw).

  7. Gas chromatography-mass spectrometric determination of traces of ether-type icing inhibitors in free-floating fuels

    Energy Technology Data Exchange (ETDEWEB)

    Shin, H.S. [Dept. of Environmental Education, Kongju National Univ., Kongju (Korea); Abuse Drug Research Center, Kongju National Univ., Kongju (Korea); Ahn, H.S. [Dept. of Environmental Science, Kongju National Univ., Kongju (Korea)

    2004-08-01

    A gas chromatographic-mass spectrometric (GC-MS) assay method has been developed for simultaneous determination of ethylene glycol monomethyl ether (EGME) and diethylene glycol monomethly ether (DEGME) in spilled aviation fuels. Ethylene glycol monobutyl ether (EGBE) and ethylene glycol monoethyl ether (EGEE) were used as internal standard and surrogate, respectively. Sample preparation consisted of back-extraction with 7 mL dichloromethane after extraction of 50 mL of fuel with 2 mL of water. The extract was concentrated to dryness, dissolved in 100 {mu}L methanol, and analyzed by GC-MS with selected-ion monitoring (SIM). The peaks had good chromatographic properties on a semi-polar column. EGME and DEGME were extracted from fuel with high recovery of 75 and 85%, with small variations, respectively. Method detection limits were 1.3 and 1.0 ng mL{sup -1} for EGME and DEGME, respectively, in spilled fuel. DEGME was detected at concentrations of 22.6 and 19.7 ng mL{sup -1} in two samples from among five free-floating samples collected in a tunnel of a subway station located in the vicinity of an army base in Korea. The method might be useful for differentiation between the fuel-types kerosene and JP-8, which might originate from a storage tank. (orig.)

  8. Bulk derivatization and cation exchange restricted access media-based trap-and-elute liquid chromatography–mass spectrometry method for determination of trace estrogens in serum

    International Nuclear Information System (INIS)

    Beinhauer, Jana; Bian, Liangqiao; Fan, Hui; Šebela, Marek; Kukula, Maciej; Barrera, Jose A.

    2015-01-01

    Highlights: • Analysis of estrogens in small volume samples at low parts-per-trillion concentration. • Charged bulk derivatization facilitates on-line ion exchange sample preparation. • On-line WCX restricted access media traps analytes, but not proteins and lipids. • Complete preparation and LC–MS/MS analysis completed in 30 min/sample. - Abstract: Estrone (E1), estradiols (α/β-E2), and estriol (E3) are four major metabolically active estrogens exerting strong biological activities at very low circulating concentrations. This paper reports a sensitive and efficient method with automated, on-line clean-up and detection to determine trace estrogens in a small volume of serum samples using liquid chromatography–electrospray ionization–tandem mass spectrometry directly, without off-line liquid–liquid or solid-phase extraction pretreatments. Serum aliquots (charcoal stripped fetal bovine serum, 100 μL) were spiked with four estrogen standards and their corresponding isotope-labeled internal standards, then bulk derivatized with 2-fluoro-1-methyl-pyridium p-toluenesulfonate (2-FMP) to establish the calibration curves and perform method validation. Calibration was established in the concentration ranges of 5–1000 pg mL −1 , and demonstrated good linearity of R 2 from 0.9944 to 0.9997 for the four derivatized estrogens. The lower detection limits obtained were 3–7 pg mL −1 . Good accuracy and precision in the range of 86–112% and 2.3–11.9%, respectively, were observed for the quality control (QC) samples at low, medium, and high concentration levels. The stability tests showed that the derivatized serum samples were stable 8 h after derivatization at room temperature and at least to 48 h if stored at −20 °C. The method was applied to measure trace estrogens in real human and bovine serum samples, and three of four estrogen compounds studied were observed and quantified

  9. A dipole-assisted solid-phase extraction microchip combined with inductively coupled plasma-mass spectrometry for online determination of trace heavy metals in natural water.

    Science.gov (United States)

    Shih, Tsung-Ting; Hsu, I-Hsiang; Chen, Shun-Niang; Chen, Ping-Hung; Deng, Ming-Jay; Chen, Yu; Lin, Yang-Wei; Sun, Yuh-Chang

    2015-01-21

    We employed a polymeric material, poly(methyl methacrylate) (PMMA), for fabricating a microdevice and then implanted the chlorine (Cl)-containing solid-phase extraction (SPE) functionality into the PMMA chip to develop an innovative on-chip dipole-assisted SPE technique. Instead of the ion-ion interactions utilized in on-chip SPE techniques, the dipole-ion interactions between the highly electronegative C-Cl moieties in the channel interior and the positively charged metal ions were employed to facilitate the on-chip SPE procedures. Furthermore, to avoid labor-intensive manual manipulation, a programmable valve manifold was designed as an interface combining the dipole-assisted SPE microchip and inductively coupled plasma-mass spectrometry (ICP-MS) to achieve the fully automated operation. Under the optimized operation conditions for the established system, the detection limits for each analyte ion were obtained based on three times the standard deviation of seven measurements of the blank eluent solution. The limits ranged from 3.48 to 20.68 ng L(-1), suggesting that this technique appears uniquely suited for determining the levels of heavy metal ions in natural water. Indeed, a series of validation procedures demonstrated that the developed method could be satisfactorily applied to the determination of trace heavy metals in natural water. Remarkably, the developed device was durable enough to be reused more than 160 times without any loss in its analytical performance. To the best of our knowledge, this is the first study reporting on the combination of a dipole-assisted SPE microchip and elemental analysis instrument for the online determination of trace heavy metal ions.

  10. Direct analysis of ultra-trace semiconductor gas by inductively coupled plasma mass spectrometry coupled with gas to particle conversion-gas exchange technique.

    Science.gov (United States)

    Ohata, Masaki; Sakurai, Hiromu; Nishiguchi, Kohei; Utani, Keisuke; Günther, Detlef

    2015-09-03

    An inductively coupled plasma mass spectrometry (ICPMS) coupled with gas to particle conversion-gas exchange technique was applied to the direct analysis of ultra-trace semiconductor gas in ambient air. The ultra-trace semiconductor gases such as arsine (AsH3) and phosphine (PH3) were converted to particles by reaction with ozone (O3) and ammonia (NH3) gases within a gas to particle conversion device (GPD). The converted particles were directly introduced and measured by ICPMS through a gas exchange device (GED), which could penetrate the particles as well as exchange to Ar from either non-reacted gases such as an air or remaining gases of O3 and NH3. The particle size distribution of converted particles was measured by scanning mobility particle sizer (SMPS) and the results supported the elucidation of particle agglomeration between the particle converted from semiconductor gas and the particle of ammonium nitrate (NH4NO3) which was produced as major particle in GPD. Stable time-resolved signals from AsH3 and PH3 in air were obtained by GPD-GED-ICPMS with continuous gas introduction; however, the slightly larger fluctuation, which could be due to the ionization fluctuation of particles in ICP, was observed compared to that of metal carbonyl gas in Ar introduced directly into ICPMS. The linear regression lines were obtained and the limits of detection (LODs) of 1.5 pL L(-1) and 2.4 nL L(-1) for AsH3 and PH3, respectively, were estimated. Since these LODs revealed sufficiently lower values than the measurement concentrations required from semiconductor industry such as 0.5 nL L(-1) and 30 nL L(-1) for AsH3 and PH3, respectively, the GPD-GED-ICPMS could be useful for direct and high sensitive analysis of ultra-trace semiconductor gas in air. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Quantitative analysis of major and trace elements in NH4HF2-modified silicate rock powders by laser ablation - inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Zhang, Wen; Hu, Zhaochu; Liu, Yongsheng; Yang, Wenwu; Chen, Haihong; Hu, Shenghong; Xiao, Hongyan

    2017-08-29

    In this paper, we described a NH 4 HF 2 digestion method as sample preparation for the rapid determination of major and trace elements in silicate rocks using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). Sample powders digested by NH 4 HF 2 at 230 °C for 3 h form ultrafine powders with a typical grain size d 80  rocks have a consistent grain morphology and size, allowing us to produce pressed powder pellets that have excellent cohesion and homogeneity suitable for laser ablation micro-analysis without the addition of binder. The influences of the digestion parameters were investigated and optimized, including the evaporation stage of removing residual NH 4 HF 2 , sample homogenization, selection of the digestion vessel and calibration strategy of quantitative analysis. The optimized NH 4 HF 2 digestion method was applied to dissolve six silicate rock reference materials (BCR-2, BHVO-2, AGV-2, RGM-2, GSP-2, GSR-1) covering a wide range of rock types. Ten major elements and thirty-five trace elements were simultaneously analyzed by LA-ICP-MS. The analytical results of the six reference materials generally agreed with the recommended values, with discrepancies of less than 10% for most elements. The analytical precision is within 5% for most major elements and within 10% for most trace elements. Compared with previous methods of LA-ICP-MS bulk analysis, our method enables the complete dissolution of refractory minerals, such as zircon, in intermediate-acidic intrusive rocks and limits contamination as well as the loss of volatile elements. Moreover, there are many advantages for the new technique, including reducing matrix effects between reference materials and samples, spiking the internal standard simply and feasibly and sample batch processing. The applicability filed of the new technique in this study was focused on the whole-rock analysis of igneous rock samples, which are from basic rocks to acid rocks (45% rock analysis

  12. Trace metal analysis in arctic aerosols by an inductively coupled plasma-time of flight-mass spectrometer combined with an inductively heated vaporizer

    International Nuclear Information System (INIS)

    Luedke, Christian; Skole, Jochen; Taubner, Kerstin; Kriews, Michael

    2005-01-01

    Two newly developed instruments were combined to analyze the trace metal content in size separated arctic aerosols during the measurement campaign ASTAR 2004 (Arctic Study of Tropospheric Aerosols, Clouds and Radiation 2004) at Spitsbergen in May-June 2004. The aim of this extensive aerosol measurement campaign was to obtain a database for model-calculations of arctic aerosol, which play an important role in the global climate change. The ASTAR project was centered on two aircraft measurement campaigns, scheduled from 2004 to 2005, addressing both aerosol and cloud measurements, combined with ground-based and satellite observations. In the present paper one example for the analysis of ground-based aerosol particles is described. The sampling of aerosol particles was performed in a well-known manner by impaction of the particles on cleaned graphite targets. By means of a cascade impactor eight size classes between 0.35 and 16.6 μm aerodynamic diameters were separated. To analyze the metal content in the aerosol particles the targets were rapidly heated up to 2700 deg. C in an inductively heated vaporizer system (IHVS). An argon flow transports the vaporized sample material into the inductively coupled plasma (ICP) used as ionization source for the time of flight-mass spectrometer (TOF-MS). The simultaneous extraction of the ions from the plasma, as realized in the TOF instrument, allows to obtain the full mass spectrum of the sample during the vaporization pulse without any limitation in the number of elements detected. With optimized experimental parameters the element content in arctic aerosol particles was determined in a mass range between 7 Li and 209 Bi. Comparing the size distribution of the elemental content of the aerosol particles, two different meteorological situations were verified. For calibration acidified reference solutions were placed on the cleaned target inside the IHVS. The limits of detection (LOD) for the element mass on the target range

  13. The laser microprobe mass analyser for determining partitioning of minor and trace elements among intimately associated macerals: an example from the Swallow Wood coal bed, Yorkshire, UK

    Science.gov (United States)

    Lyons, P.C.; Morelli, J.J.; Hercules, D.M.; Lineman, D.; Thompson-Rizer, C. L.; Dulong, F.T.

    1990-01-01

    A study of the elemental composition of intimately associated coal macerals in the English Swallow Wood coal bed was conducted using a laser microprobe mass analyser, and indicated a similar trace and minor elemental chemistry in the vitrinite and cutinite and a different elemental signature in the fusinite. Three to six sites were analysed within each maceral during the study by laser micro mass spectrometry (LAMMS). Al, Ba, Ca, Cl, Cr, Dy, F, Fe, Ga, K, Li, Mg, Na, S, Si, Sr, Ti, V, and Y were detected by LAMMS in all three macerals but not necessarily at each site analysed. The signal intensities of major isotopic peaks were normalized to the signal intensity of the m z 85 peak (C7H) to determine the relative minor- and trace-element concentrations among the three dominant macerals. The vitrinite and the cutinite were depleted in Ba, Ca, Dy, Li, Mg, Sr, and Y relative to their concentrations observed in the fusinite. The cutinite was distinguished over vitrinite by less Ti, V, Cr and Ca, and K Ca $ ??1 (relative signal intensities). The fusinite, relative to the cutinite and vitrinite, was relatively depleted in Cr, Sc, Ti, and V. The fusinite, as compared with both the cutinite and vitrinite, was relatively enriched in Ba, Ca, Dy, Li, Mg, Sr, and Y, and also showed the most intense m z 64, 65, 66 signals (possibly S2+, HS2+, H2S2+, respectively). The LAMMS data indicate a common source for most elements and selective loss from the maceral precursors in the peat or entrapment of certain elements as mineral matter, most likely during the peat stage or during early diagenesis. The relatively high amounts of Ba, Ca, Dy, Li, Mg, Sr, and Y in the fusinite are consistent with micron and submicron mineral-matter inclusions such as carbonates and Ca-Al phosphates (probably crandallite group minerals). Mineralogical data on the whole coal, the LAMMS chemistry of the vitrinite and cutinite, and scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDAX) of

  14. Bioavailability of sediment-associated and low-molecular-mass species of radionuclides/trace metals to the mussel Mytilus edulis

    Energy Technology Data Exchange (ETDEWEB)

    Borretzen, Peer [Department of Plant and Environmental Sciences, P.O. Box 50003, Norwegian University of Life Sciences, N-1432 As (Norway)], E-mail: peer.borretzen@gmail.com; Salbu, Brit [Department of Plant and Environmental Sciences, P.O. Box 50003, Norwegian University of Life Sciences, N-1432 As (Norway)

    2009-04-15

    Sediments can act as a sink for contaminants in effluents from industrial and nuclear installations or when released from dumped waste. However, contaminated sediments may also act as a potential source of radionuclides and trace metals to the water phase due to remobilisation of metals as dissolved species and resuspension of particles. The marine mussel Mytilus edulis is a filter-feeding organism that via the gills is subjected to contaminants in dissolved form and from contaminants associated to suspended particles via the digestive system. In this paper the bioavailability of sediment-associated and seawater diluted Cs, Co, Cd and Zn radioactive tracers to the filtering bivalve M. edulis has been examined. The mussels were exposed to tracers diluted in ultrafiltered (<10 kDa) seawater (Low Molecular Mass form) or to tracers associated with sediment particles from the Stepovogo Fjord at Novaya Zemlya in short-term uptake experiments, followed by 1-month depuration experiments in flow-through tanks. A toxicokinetic model was fitted to the uptake and depuration data, and the obtained parameters were used to simulate the significance of the two uptake pathways at different suspended sediment loads and sediment-seawater distribution coefficients. The results of the model simulations, assuming steady state conditions, suggest that resuspended particles from contaminated sediments can be a highly significant pathway for mussels in the order {sup 109}Cd {approx_equal} {sup 65}Zn < {sup 134}Cs < {sup 60}Co. The significance increases with higher suspended sediment load and with higher K{sub d}. Furthermore, the experimental depuration data suggest that Cs is retained longer and Co, Cd and Zn shorter by the mussels when associated with ingested sediments, than if the metals are taken up from the low molecular mass (LMM) phase.

  15. Direct atmospheric pressure chemical ionization-tandem mass spectrometry for the continuous real-time trace analysis of benzene, toluene, ethylbenzene, and xylenes in ambient air.

    Science.gov (United States)

    Badjagbo, Koffi; Picard, Pierre; Moore, Serge; Sauvé, Sébastien

    2009-05-01

    Real-time monitoring of benzene, toluene, ethylbenzene, and xylenes (BTEX) in ambient air is essential for the early warning detection associated with the release of these hazardous chemicals and in estimating the potential exposure risks to humans and the environment. We have developed a tandem mass spectrometry (MS/MS) method for continuous real-time determination of ambient trace levels of BTEX. The technique is based on the sampling of air via an atmospheric pressure inlet directly into the atmospheric pressure chemical ionization (APCI) source. The method is linear over four orders of magnitude, with correlation coefficients greater than 0.996. Low limits of detection in the range 1-2 microg/m(3) are achieved for BTEX. The reliability of the method was confirmed through the evaluation of quality parameters such as repeatability and reproducibility (relative standard deviation below 8% and 10%, respectively) and accuracy (over 95%). The applicability of this method to real-world samples was evaluated through measurements of BTEX levels in real ambient air samples and results were compared with a reference GC-FID method. This direct APCI-MS/MS method is suitable for real-time analysis of BTEX in ambient air during regulation surveys as well as for the monitoring of industrial processes or emergency situations.

  16. Speciation Analysis of Trace Mercury in Sea Cucumber Species of Apostichopus japonicus Using High-Performance Liquid Chromatography Conjunction With Inductively Coupled Plasma Mass Spectrometry.

    Science.gov (United States)

    Liu, Hao; Luo, Jiaoyang; Ding, Tong; Gu, Shanyong; Yang, Shihai; Yang, Meihua

    2018-03-25

    In this paper, a simple and cost-effective method using high-performance liquid chromatography in conjunction with inductively coupled plasma mass spectrometry with a rapid ultrasound-assisted extraction was used for analysis speciation of trace mercury in sea cucumber species of Apostichopus japonicus. The effective separation of inorganic mercury, methylmercury, and ethylmercury was achieved within 10 min using Agilent ZORBAX SB-C 18 analytical and guard columns with an isocratic mobile phase consisting of 8% methanol and 92% H 2 O containing 0.12% L-cysteine (m/v) and 0.01 mol/L ammonium acetate. Mercury species were extracted from A. japonicus samples using a solution containing 2-mercaptoethanol, L-cysteine, and hydrochloric acid and sonicating for 0.5 h. The limits of detection of inorganic mercury, methylmercury, and ethylmercury were 0.12, 0.08, and 0.20 μg/L, and the minimum detectable concentrations (measured at 0.500 g sample volume in 10.00 mL) were 2.4, 1.6, and 4.0 μg/kg, respectively. Analysis of a scallop certified reference material (GBW 10024) revealed accordance between the experimental and certified values. This study provides a reference for the evaluation of mercury speciation in sea cucumber and other seafood.

  17. Direct trace-elemental analysis of urine samples by laser ablation-inductively coupled plasma mass spectrometry after sample deposition on clinical filter papers.

    Science.gov (United States)

    Aramendía, Maite; Rello, Luis; Vanhaecke, Frank; Resano, Martín

    2012-10-16

    Collection of biological fluids on clinical filter papers shows important advantages from a logistic point of view, although analysis of these specimens is far from straightforward. Concerning urine analysis, and particularly when direct trace elemental analysis by laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) is aimed at, several problems arise, such as lack of sensitivity or different distribution of the analytes on the filter paper, rendering obtaining reliable quantitative results quite difficult. In this paper, a novel approach for urine collection is proposed, which circumvents many of these problems. This methodology consists on the use of precut filter paper discs where large amounts of sample can be retained upon a single deposition. This provides higher amounts of the target analytes and, thus, sufficient sensitivity, and allows addition of an adequate internal standard at the clinical lab prior to analysis, therefore making it suitable for a strategy based on unsupervised sample collection and ulterior analysis at referral centers. On the basis of this sampling methodology, an analytical method was developed for the direct determination of several elements in urine (Be, Bi, Cd, Co, Cu, Ni, Sb, Sn, Tl, Pb, and V) at the low μg L(-1) level by means of LA-ICPMS. The method developed provides good results in terms of accuracy and LODs (≤1 μg L(-1) for most of the analytes tested), with a precision in the range of 15%, fit-for-purpose for clinical control analysis.

  18. Trace-level determination of polar flavour compounds in butter by solid-phase extraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Adahchour, M; Vreuls, R J; van der Heijden, A; Brinkman, U A

    1999-06-04

    Volatile compounds are responsible for the aromas of butter. A simple technique for the determination of these components is described which is based on solid-phase extraction (SPE) after melting of the butter and separation of the aqueous phase from the fat. Volatile flavours present in the water fraction are collected by off-line SPE on cartidges packed with a copolymer sorbent. After desorption with 500 microliters of methyl acetate, 1-microliter aliquots are quantified and/or identified by gas chromatography-mass spectrometry. The procedure was tested with respect to recovery, linearity and limit of detection in real-life samples using five polar model analytes. It allows the characterisation of polar flavour compounds in butter prior to and after heat treatment at 170 degrees C. From the five model compounds, vanillin, traces of diacetyl and maltol were found to be present in the butter samples. After heat treatment 500-1000-fold increased concentration of maltol, and substantial amounts of furaneol were detected.

  19. Comparison of the Detection Characteristics of Trace Species Using Laser-Induced Breakdown Spectroscopy and Laser Breakdown Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Zhenzhen Wang

    2015-03-01

    Full Text Available The rapid and precise element measurement of trace species, such as mercury, iodine, strontium, cesium, etc. is imperative for various applications, especially for industrial needs. The elements mercury and iodine were measured by two detection methods for comparison of the corresponding detection features. A laser beam was focused to induce plasma. Emission and ion signals were detected using laser-induced breakdown spectroscopy (LIBS and laser breakdown time-of-flight mass spectrometry (LB-TOFMS. Multi-photon ionization and electron impact ionization in the plasma generation process can be controlled by the pressure and pulse width. The effect of electron impact ionization on continuum emission, coexisting molecular and atomic emissions became weakened in low pressure condition. When the pressure was less than 1 Pa, the plasma was induced by laser dissociation and multi-photon ionization in LB-TOFMS. According to the experimental results, the detection limits of mercury and iodine in N2 were 3.5 ppb and 60 ppb using low pressure LIBS. The mercury and iodine detection limits using LB-TOFMS were 1.2 ppb and 9.0 ppb, which were enhanced due to different detection features. The detection systems of LIBS and LB-TOFMS can be selected depending on the condition of each application.

  20. Trace analysis of trimethoprim and sulfonamide, macrolide, quinolone, and tetracycline antibiotics in chlorinated drinking water using liquid chromatography electrospray tandem mass spectrometry

    Science.gov (United States)

    Ye, Z.; Weinberg, H.S.; Meyer, M.T.

    2007-01-01

    A multirun analytical method has been developed and validated for trace determination of 24 antibiotics including 7 sulfonamides, 3 macrolides, 7 quinolones, 6 tetracyclines, and trimethoprim in chlorine-disinfected drinking water using a single solid-phase extraction method coupled to liquid chromatography with positive electrospray tandem mass spectrometry detection. The analytes were extracted by a hydrophilic-lipophilic balanced resin and eluted with acidified methanol (0.1% formic acid), resulting in analyte recoveries generally above 90%. The limits of quantitation were mostly below 10 ng/L in drinking water. Since the concentrated sample matrix typically caused ion suppression during electrospray ionization, the method of standard addition was used for quantitation. Chlorine residuals in drinking water can react with some antibiotics, but ascorbic acid was found to be an effective chlorine quenching agent without affecting the analysis and stability of the antibiotics in water. A preliminary occurrence study using this method revealed the presence of some antibiotics in drinking waters, including sulfamethoxazole (3.0-3.4 ng/L), macrolides (1.4-4.9 ng/L), and quinolones (1.2-4.0 ng/L). ?? 2007 American Chemical Society.

  1. Enantioselective column coupled electrophoresis employing large bore capillaries hyphenated with tandem mass spectrometry for ultra-trace determination of chiral compounds in complex real samples.

    Science.gov (United States)

    Piešťanský, Juraj; Maráková, Katarína; Kovaľ, Marián; Havránek, Emil; Mikuš, Peter

    2015-12-01

    A new multidimensional analytical approach for the ultra-trace determination of target chiral compounds in unpretreated complex real samples was developed in this work. The proposed analytical system provided high orthogonality due to on-line combination of three different methods (separation mechanisms), i.e. (1) isotachophoresis (ITP), (2) chiral capillary zone electrophoresis (chiral CZE), and (3) triple quadrupole mass spectrometry (QqQ MS). The ITP step, performed in a large bore capillary (800 μm), was utilized for the effective sample pretreatment (preconcentration and matrix clean-up) in a large injection volume (1-10 μL) enabling to obtain as low as ca. 80 pg/mL limits of detection for the target enantiomers in urine matrices. In the chiral CZE step, the different chiral selectors (neutral, ionizable, and permanently charged cyclodextrins) and buffer systems were tested in terms of enantioselectivity and influence on the MS detection response. The performance parameters of the optimized ITP - chiral CZE-QqQ MS method were evaluated according to the FDA guidance for bioanalytical method validation. Successful validation and application (enantioselective monitoring of renally eliminated pheniramine and its metabolite in human urine) highlighted great potential of this chiral approach in advanced enantioselective biomedical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Detection and quantitation of trace phenolphthalein (in pharmaceutical preparations and in forensic exhibits) by liquid chromatography-tandem mass spectrometry, a sensitive and accurate method.

    Science.gov (United States)

    Sharma, Kakali; Sharma, Shiba P; Lahiri, Sujit C

    2013-01-01

    Phenolphthalein, an acid-base indicator and laxative, is important as a constituent of widely used weight-reducing multicomponent food formulations. Phenolphthalein is an useful reagent in forensic science for the identification of blood stains of suspected victims and for apprehending erring officials accepting bribes in graft or trap cases. The pink-colored alkaline hand washes originating from the phenolphthalein-smeared notes can easily be determined spectrophotometrically. But in many cases, colored solution turns colorless with time, which renders the genuineness of bribe cases doubtful to the judiciary. No method is known till now for the detection and identification of phenolphthalein in colorless forensic exhibits with positive proof. Liquid chromatography-tandem mass spectrometry had been found to be most sensitive, accurate method capable of detection and quantitation of trace phenolphthalein in commercial formulations and colorless forensic exhibits with positive proof. The detection limit of phenolphthalein was found to be 1.66 pg/L or ng/mL, and the calibration curve shows good linearity (r(2) = 0.9974). © 2012 American Academy of Forensic Sciences.

  3. Determination of 20 trace elements and arsenic species for a realgar-containing traditional Chinese medicine Niuhuang Jiedu tablets by direct inductively coupled plasma-mass spectrometry and high performance liquid chromatography-inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Jin, Pengfei; Liang, Xiaoli; Xia, Lufeng; Jahouh, Farid; Wang, Rong; Kuang, Yongmei; Hu, Xin

    2016-01-01

    Niuhuang Jiedu tablet (NHJDT) is a realgar-containing traditional Chinese medicine. A direct inductively coupled plasma-mass spectrometry (ICP-MS) method for the simultaneous determination of 20 trace elements (Mg, K, Ca, Na, Fe, As, Zn, Sr, Ba, Cu, Mn, Ni, Pb, V, Cr, Se, Co, Mo, Cd, Hg) in NHJDT, as well as in water, gastric fluid and intestinal fluid was established. Meanwhile, a high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) method was developed for the determination of arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and for the identification of arsenobetaine (AsB) and arsenocholine (AsC) in these extracts. Both methods were fully validated in the respect of linearity, sensitivity, precision, stability and accuracy. The reliability of the ICP-MS method was further evaluated using a certified standard reference material prepared from dried tomato leaves (NIST, SRM 1572a). The analysis showed that some manufacturers formulated lower amount of realgar than required in the Chinese Pharmacopoeia (ChP) in their preparations. In addition, almost same extraction profiles for total As and inorganic As were found in water and in gastrointestinal fluids, while higher extraction rates for other 19 elements were observed in gastrointestinal fluids. Our findings show that the toxicities of Hg, Cu, Cd and Pb in NHJDP are low, while the real As toxicity in NHJDT should be deeply investigated. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. Bulk derivatization and cation exchange restricted access media-based trap-and-elute liquid chromatography–mass spectrometry method for determination of trace estrogens in serum

    Energy Technology Data Exchange (ETDEWEB)

    Beinhauer, Jana [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Bian, Liangqiao [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Fan, Hui [Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX (United States); Šebela, Marek [Department of Biochemistry, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Centre of the Region Haná for Biotechnological and Agricultural Research - Department of Protein Biochemistry and Proteomics, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc (Czech Republic); Kukula, Maciej [Shimadzu Center for Advanced Analytical Chemistry, The University of Texas at Arlington, Arlington, TX (United States); Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); Barrera, Jose A. [Shimadzu Institute for Research Technologies, The University of Texas at Arlington, Arlington, TX (United States); and others

    2015-02-09

    Highlights: • Analysis of estrogens in small volume samples at low parts-per-trillion concentration. • Charged bulk derivatization facilitates on-line ion exchange sample preparation. • On-line WCX restricted access media traps analytes, but not proteins and lipids. • Complete preparation and LC–MS/MS analysis completed in 30 min/sample. - Abstract: Estrone (E1), estradiols (α/β-E2), and estriol (E3) are four major metabolically active estrogens exerting strong biological activities at very low circulating concentrations. This paper reports a sensitive and efficient method with automated, on-line clean-up and detection to determine trace estrogens in a small volume of serum samples using liquid chromatography–electrospray ionization–tandem mass spectrometry directly, without off-line liquid–liquid or solid-phase extraction pretreatments. Serum aliquots (charcoal stripped fetal bovine serum, 100 μL) were spiked with four estrogen standards and their corresponding isotope-labeled internal standards, then bulk derivatized with 2-fluoro-1-methyl-pyridium p-toluenesulfonate (2-FMP) to establish the calibration curves and perform method validation. Calibration was established in the concentration ranges of 5–1000 pg mL{sup −1}, and demonstrated good linearity of R{sup 2} from 0.9944 to 0.9997 for the four derivatized estrogens. The lower detection limits obtained were 3–7 pg mL{sup −1}. Good accuracy and precision in the range of 86–112% and 2.3–11.9%, respectively, were observed for the quality control (QC) samples at low, medium, and high concentration levels. The stability tests showed that the derivatized serum samples were stable 8 h after derivatization at room temperature and at least to 48 h if stored at −20 °C. The method was applied to measure trace estrogens in real human and bovine serum samples, and three of four estrogen compounds studied were observed and quantified.

  5. Molecularly imprinted solid phase extraction using stable isotope labeled compounds as template and liquid chromatography-mass spectrometry for trace analysis of bisphenol A in water sample

    International Nuclear Information System (INIS)

    Kawaguchi, Migaku; Hayatsu, Yoshio; Nakata, Hisao; Ishii, Yumiko; Ito, Rie; Saito, Koichi; Nakazawa, Hiroyuki

    2005-01-01

    We have developed a molecularly imprinted polymer (MIP) using a stable isotope labeled compound as the template molecule and called it the ''isotope molecularly imprinted polymer'' (IMIP). In this study, bisphenol A (BPA) was used as the model compound. None imprinted polymer (NIP), MIP, dummy molecularly imprinted polymer (DMIP) and IMIP were prepared by the suspension polymerization method using without template, BPA, 4-tert-butylphenol (BP) and bisphenol A-d 16 (BPA-d 16 ), respectively. The polymers were subjected to molecularly imprinted solid phase extraction (MI-SPE), and the extracted samples were subjected to liquid chromatography-mass spectrometry (LC-MS). Although the leakage of BPA-d 16 from the IMIP was observed and that of BPA was not observed. The selectivity factors of MIP and IMIP for BPA were 4.45 and 4.43, respectively. Therefore, IMIP had the same molecular recognition ability as MIP. When MI-SPE with IMIP was used and followed by LC-MS in the analysis of river water sample, the detection limit of BPA was 1 ppt with high sensitivity. Moreover, the average recovery was higher than 99.8% (R.S.D.: 3.7%) by using bisphenol A- 13 C 12 (BPA- 13 C 12 ) as the surrogate standard. In addition, the IMIP were employed in MI-SPE of BPA in river water sample by LC-MS. The concentration of BPA in the river water sample was determined to be 32 pg ml -1 . We confirmed that it was possible to measure trace amounts of a target analyte by MI-SPE using IMIP

  6. Trace analysis of three fungicides in animal origin foods with a modified QuEChERS method and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Mu, Zhaobin; Feng, Xiaoxiao; Zhang, Yun; Zhang, Hongyan

    2016-02-01

    A multi-residue method based on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS), was developed and validated for the determination of three selected fungicides (propiconazole, pyraclostrobin, and isopyrazam) in seven animal origin foods. The overall recoveries at the three spiking levels of 0.005, 0.05, and 0.5 mg kg(-1) spanned between 72.3 and 101.4% with relative standard deviation (RSD) values between 0.7 and 14.9%. The method shows good linearity in the concentrations between 0.001 and 1 mg L(-1) with the coefficient of determination (R (2)) value >0.99 for each target analyte. The limit of detections (LODs) for target analytes were between 0.04 and 1.26 μg kg(-1), and the limit of quantifications (LOQs) were between 0.13 and 4.20 μg kg(-1). The matrix effect for each individual compound was evaluated through the study of ratios of the areas obtained in solvent and matrix standards. The optimized method provided a negligible matrix effect for propiconazole within 20%, whereas for pyraclostrobin and isopyrazam, the matrix effect was relatively significant with a maximum value of 49.8%. The developed method has been successfully applied to the analysis of 210 animal origin samples obtained from 16 provinces of China. The results suggested that the developed method was satisfactory for trace analysis of three fungicides in animal origin foods.

  7. Enhancement of sensitivity in the determination of organic trace compounds in complex matrices with liquid chromatography-mass spectrometry (LC-MS)

    International Nuclear Information System (INIS)

    Mascher, D.G.

    2002-05-01

    The PhD-thesis deals with 'enhancement of sensitivity in the determination of organic trace compounds in complex matrices with liquid chromatography-mass spectrometry (LC-MS)'. Almost the most important factor is the enhancement of the ionization yield with Atmospheric Pressure Chemical Ionization (APCI) or Electrospray Ionization (ESI) in LC-MS. Ionization yields of different compounds can vary by a factor of 10000. Three ways to solve this problem of little ionization yield were tried: 1) Modification of the mobile phase in HPLC 2) Chemical modification of the analytes 3) A new type of ionization called Atmospheric Pressure Photo Ionization (APPI). ad 1) By using specific additives to mobile phases ion suppression that might derive from an ion pair reagent that was necessary for chromatography could be omitted. General remarks cannot be done. ad 2) Chemical modification or so called derivatization is well known for UV- and fluorescence-detection for a long period of time. As substances containing nitrogene (e.g. primary, secondary or tertiary amines) often have good ionization yields, poor or relatively poor ionizable substances like carboxylic acids, sugars and partially phenolic steroids were used as analytes for derivatization reactions. By using Dansyl as Dansylchlorid or Dansylhydrazine a basic derivatization agent could be found that ionizes very well. A 200 times more sensitive determination of estrogenes is possible after derivatization with Dansylchlorid. Using a tandem-mass-spectrometer a lower limit of quantification of 2 pg/mL plasma could be reached by using 1 mL of plasma. For ketones like carvon and campher an enhancement by a factor of 500 and 4000 could be reached by using Dansylhydrazine as the derivatization agent. For fatty acids DMEQ as derivatization agent enhanced the sensitivity by a factor of 20 to 100. ad 3) APPI as a new ionization mode showed really good results for specific molecules. Relatively unpolar substances as diphenylsulfide

  8. Trace analysis

    International Nuclear Information System (INIS)

    Warner, M.

    1987-01-01

    What is the current state of quantitative trace analytical chemistry? What are today's research efforts? And what challenges does the future hold? These are some of the questions addressed at a recent four-day symposium sponsored by the National Bureau of Standards (NBS) entitled Accuracy in Trace Analysis - Accomplishments, Goals, Challenges. The two plenary sessions held on the first day of the symposium reviewed the history of quantitative trace analysis, discussed the present situation from academic and industrial perspectives, and summarized future needs. The remaining three days of the symposium consisted of parallel sessions dealing with the measurement process; quantitation in materials; environmental, clinical, and nutrient analysis; and advances in analytical techniques

  9. Analytical evaluation of nebulizers for the introduction of acetic acid extracts aiming at the determination of trace elements by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gois, Jefferson S. de; Maranhao, Tatiane de A. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-970, Florianopolis, SC (Brazil); Oliveira, Fernando J.S. [Petroleo Brasileiro S.A., Gerencia de Meio Ambiente, Rio de Janeiro, RJ (Brazil); Frescura, Vera L.A.; Curtius, Adilson J. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-970, Florianopolis, SC (Brazil); Borges, Daniel L.G., E-mail: daniel.borges@ufsc.br [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-970, Florianopolis, SC (Brazil)

    2012-11-15

    Most of the official procedures aiming at classification of solid waste toxicity take into account metal solubility and bioavailability by means of extraction experiments using acetic acid solutions. Hence, the aim of this work was to investigate and optimize conditions to suppress the effect of acetic acid on the determination of trace elements using inductively coupled plasma mass spectrometry. The performance of four nebulizers (cross-flow (CFN), ultrasonic (USN), Meinhard (MN) and MicroMist (MMN)) were compared as to their efficiency in minimizing spectral and non-spectral effects on the determination of Ag, As, Ba, Cd, Cr, Hg, Pb and Se, with the ultimate goal to analyze acetic acid extracts obtained from solid waste residues. Operating conditions (desolvation temperatures for USN, RF power and nebulizer gas flow rates) were optimized individually for each nebulizer and for all analytes maintained in 0.14 mol L{sup -1} HNO{sub 3} solutions and in solutions prepared with acetic acid and acetic acid + NaOH, adjusted to pH 2.88 and 4.93, respectively. Pronounced non-spectral interferences for {sup 75}As and {sup 82}Se were observed in the presence of acetic acid for CF and MN, although to a less extent also for MMN and USN. Signal increase for blank solutions measured at m/z 208 ({sup 208}Pb) for CFN and MN, 107 ({sup 107}Ag) for USN and MN coupled to a cyclonic chamber and, m/z 82 ({sup 82}Se) for USN was observed, indicating an increased risk of spectral interference upon an increase in the concentration of acetic acid. Signal increase at specific m/z ratios, however, was not significant when the MMN was used, with the exception of m/z 52 ({sup 52}Cr) in acetic acid solutions, arising from the formation of {sup 40}Ar{sup 12}C{sup +}. This same effect was noticed for all nebulizers, although at noticeably different intensities. A signal stability study was performed, demonstrating that variations in the analytical signal were within a 20% range for all analytes

  10. A Comparative Study of Selected Trace Element Content in Malay and Chinese Traditional Herbal Medicine (THM Using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS

    Directory of Open Access Journals (Sweden)

    Sharifah Mohamad

    2013-02-01

    Full Text Available A total of 60 products of traditional herbal medicine (THM in various dosage forms of herbal preparation were analyzed to determine selected trace elements (i.e., Zn, Mn, Cu, Cd, and Se using ICP-MS. Thirty types of both Chinese and Malay THMs were chosen to represent each population. The closed vessel acid microwave digestion method, using CEM MARS 5, was employed for the extraction of the selected trace elements. The digestion method applied was validated by using certified reference material from the Trace Element in Spinach Leaves (SRM1570a. The recoveries of all elements were found to be in the range of 85.3%–98.9%. The results indicated that Zn, Mn, Cu, Cd and Se have their own trends of concentrations in all samples studied. The daily intake concentrations of the elements were in the following order: Mn > Zn > Cu > Se > Cd. Concentrations of all five elements were found to be dominant in Chinese THMs. The essentiality of the selected trace elements was also assessed, based on the recommended daily allowance (RDA, adequate intake (AI and the United States Pharmacopeia (USP for trace elements as reference. The concentrations of all elements studied were below the RDA, AI and USP values, which fall within the essential concentration range, except for cadmium.

  11. Multielement determination of trace elements in seawater by inductively coupled plasma mass spectrometry after tandem preconcentration with cooperation of chelating resin adsorption and lanthanum coprecipitation

    International Nuclear Information System (INIS)

    Yabutani, Tomoki; Chiba, Koichi; Haraguchi, Hiroki

    2001-01-01

    A tandem preconcentration method, in which chelating resin adsorption and La coprecipitation were cooperatively employed for preconcentration, was developed as a pretreatment method for simultaneous multielement determination of trace elements in seawater by ICP-MS. First, the seawater sample (250 ml) was treated with a chelating resin for preconcentration of trace elements, and then trace elements with good recoveries were determined by ICP-MS. Trace elements with the chemical properties of oxoanion- and hydride-formation, which were poorly recovered in the chelating resin preconcentration, were further subjected to preconcentration by La coprecipitation. As a result, more than 30 elements could be determined in the concentration range from 9.6 μg L -1 for Mo to 0.00018 μg L -1 for Tm, when the present tandem method was applied to the analysis of open seawater standard reference material (NASS-4). Furthermore, the analytical results for open seawater reference materials were compared with those for coastal seawater reference material as well as for coastal seawater collected in the Ise Bay. It was found that the multielement data for trace elements in these seawater samples clearly showed different elemental distributions, reflecting the different marine environments. (author)

  12. The coupling of capillary electrophoresis-inductively coupled plasma mass spectrometer as a speciation instrument for actinides at trace level; Le couplage electrophorese capillaire-spectrometre de masse a source plasma en tant qu'instrument de speciation des actinides a l'etat de traces

    Energy Technology Data Exchange (ETDEWEB)

    Delorme, A

    2004-07-01

    An interface between the separation technique (capillary electrophoresis) and the analytical technique (Inductively Coupled Plasma - Mass Spectrometer) was developed. In that sense, bibliographic and parametric studies allowed to define necessary conditions for the good working of both techniques. The results obtained led to the realisation of an interface capillary electrophoresis / ICP-MS (CE / ICP-MS). This one was experimentally validated on classical separations (alkalis / earth-alkalis and lanthanides) and the detection limit of the analytical system was determined equal to 4 x 10{sup -11} mol.L{sup -1} for plutonium. This result exhibits a gain in detection limit of a factor higher than 10{sup 4} compared to the capillary electrophoresis in standard detection (UV). The studies were made in order to check the capacity of the CE / ICP-MS coupling as a speciation instrument for actinides at trace level and to define the associated analytical procedures. The coupling turned out to be a suited instrument for the determination of absolute electrophoretic mobilities at infinite dilution (physico-chemical property which allows to predict the migration time of an ion under an electrical field in a given electrolyte), for the determination of thermodynamic constants and for the separation of different actinide oxidation states in solution. (author)

  13. Determination of low concentrations of iron, arsenic, selenium, cadmium, and other trace elements in natural samples using an octopole collision/reaction cell equipped quadrupole-inductively coupled plasma mass spectrometer.

    Science.gov (United States)

    Dial, Angela R; Misra, Sambuddha; Landing, William M

    2015-04-30

    Accurate determination of trace metals has many applications in environmental and life sciences, such as constraining the cycling of essential micronutrients in biological production and employing trace metals as tracers for anthropogenic pollution. Analysis of elements such as Fe, As, Se, and Cd is challenged by the formation of polyatomic mass spectrometric interferences, which are overcome in this study. We utilized an Octopole Collision/Reaction Cell (CRC)-equipped Quadrupole-Inductively Coupled Plasma Mass Spectrometer for the rapid analysis of small volume samples (~250 μL) in a variety of matrices containing HNO3 and/or HCl. Efficient elimination of polyatomic interferences was demonstrated by the use of the CRC in Reaction Mode (RM; H2 gas) and in Collision-Reaction Mode (CRM; H2 and He gas), in addition to hot plasma (RF power 1500 W) and cool plasma (600 W) conditions. It was found that cool plasma conditions with RM achieved the greatest signal sensitivity while maintaining low detection limits (i.e. (56) Fe in 0.44 M HNO3 has a sensitivity of 160,000 counts per second (cps)-per-1 µg L(-1) and a limit of detection (LoD) of 0.86 ng L(-1) ). The average external precision was ≤ ~10% for minor (≤10 µg L(-1) ) elements measured in a 1:100 dilution of NIST 1643e and for iron in rainwater samples under all instrumental operating conditions. An improved method has been demonstrated for the rapid multi-element analysis of trace metals that are challenged by polyatomic mass spectrometric interferences, with a focus on (56) Fe, (75) As, (78) Se and (111) Cd. This method can contribute to aqueous environmental geochemistry and chemical oceanography, as well as other fields such as forensic chemistry, agriculture, food chemistry, and pharmaceutical sciences. Copyright © 2015 John Wiley & Sons, Ltd.

  14. An off-line automated preconcentration system with ethylenediaminetriacetate chelating resin for the determination of trace metals in seawater by high-resolution inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Minami, Tomoharu; Konagaya, Wataru; Zheng, Linjie; Takano, Shotaro; Sasaki, Masanobu; Murata, Rena; Nakaguchi, Yuzuru; Sohrin, Yoshiki

    2015-01-07

    A novel automated off-line preconcentration system for trace metals (Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in seawater was developed by improving a commercially available solid-phase extraction system SPE-100 (Hiranuma Sangyo). The utilized chelating resin was NOBIAS Chelate-PA1 (Hitachi High-Technologies) with ethylenediaminetriacetic acid and iminodiacetic acid functional groups. Parts of the 8-way valve made of alumina and zirconia in the original SPE-100 system were replaced with parts made of polychlorotrifluoroethylene in order to reduce contamination of trace metals. The eluent pass was altered for the back flush elution of trace metals. We optimized the cleaning procedures for the chelating resin column and flow lines of the preconcentration system, and developed a preconcentration procedure, which required less labor and led to a superior performance compared to manual preconcentration (Sohrin et al.). The nine trace metals were simultaneously and quantitatively preconcentrated from ∼120 g of seawater, eluted with ∼15 g of 1M HNO3, and determined by HR-ICP-MS using the calibration curve method. The single-step preconcentration removed more than 99.998% of Na, K, Mg, Ca, and Sr from seawater. The procedural blanks and detection limits were lower than the lowest concentrations in seawater for Mn, Ni, Cu, and Pb, while they were as low as the lowest concentrations in seawater for Al, Fe, Co, Zn, and Cd. The accuracy and precision of this method were confirmed by the analysis of reference seawater samples (CASS-5, NASS-5, GEOTRACES GS, and GD) and seawater samples for vertical distribution in the western North Pacific Ocean. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Quantification and micron-scale imaging of spatial distribution of trace beryllium in shrapnel fragments and metallurgic samples with correlative fluorescence detection method and secondary ion mass spectrometry (SIMS).

    Science.gov (United States)

    Abraham, J L; Chandra, S; Agrawal, A

    2014-11-01

    Recently, a report raised the possibility of shrapnel-induced chronic beryllium disease from long-term exposure to the surface of retained aluminum shrapnel fragments in the body. Since the shrapnel fragments contained trace beryllium, methodological developments were needed for beryllium quantification and to study its spatial distribution in relation to other matrix elements, such as aluminum and iron, in metallurgic samples. In this work, we developed methodology for quantification of trace beryllium in samples of shrapnel fragments and other metallurgic sample-types with main matrix of aluminum (aluminum cans from soda, beer, carbonated water and aluminum foil). Sample preparation procedures were developed for dissolving beryllium for its quantification with the fluorescence detection method for homogenized measurements. The spatial distribution of trace beryllium on the sample surface and in 3D was imaged with a dynamic secondary ion mass spectrometry instrument, CAMECA IMS 3f secondary ion mass spectrometry ion microscope. The beryllium content of shrapnel (∼100 ppb) was the same as the trace quantities of beryllium found in aluminum cans. The beryllium content of aluminum foil (∼25 ppb) was significantly lower than cans. SIMS imaging analysis revealed beryllium to be distributed in the form of low micron-sized particles and clusters distributed randomly in X-Y- and Z dimensions, and often in association with iron, in the main aluminum matrix of cans. These observations indicate a plausible formation of Be-Fe or Al-Be alloy in the matrix of cans. Further observations were made on fluids (carbonated water) for understanding if trace beryllium in cans leached out and contaminated the food product. A direct comparison of carbonated water in aluminum cans and plastic bottles revealed that beryllium was below the detection limits of the fluorescence detection method (∼0.01 ppb). These observations indicate that beryllium present in aluminum matrix was either

  16. Tracing Clues

    DEFF Research Database (Denmark)

    Feldt, Liv Egholm

    The past is all messiness and blurred relations. However, we tend to sort the messiness out through rigorous analytical studies leaving the messiness behind. Carlo Ginzburgs´ article Clues. Roots of an Evidential Paradigm from 1986 invigorates methodological elements of (historical) research, which...... central methodological elements will be further elaborated and discussed through a historical case study that traces how networks of philanthropic concepts and practices influenced the Danish welfare state in the period from the Danish constitution of 1849 until today. The overall aim of this paper...

  17. Quantification and micron-scale imaging of spatial distribution of trace beryllium in shrapnel fragments and metallurgic samples with correlative fluorescence detection method and secondary ion mass spectrometry (SIMS)

    Science.gov (United States)

    Abraham, Jerrold L.; Chandra, Subhash; Agrawal, Anoop

    2014-01-01

    Recently, a report raised the possibility of shrapnel-induced chronic beryllium disease (CBD) from long-term exposure to the surface of retained aluminum shrapnel fragments in the body. Since the shrapnel fragments contained trace beryllium, methodological developments were needed for beryllium quantification and to study its spatial distribution in relation to other matrix elements, such as aluminum and iron, in metallurgic samples. In this work, we developed methodology for quantification of trace beryllium in samples of shrapnel fragments and other metallurgic sample-types with main matrix of aluminum (aluminum cans from soda, beer, carbonated water, and aluminum foil). Sample preparation procedures were developed for dissolving beryllium for its quantification with the fluorescence detection method for homogenized measurements. The spatial distribution of trace beryllium on the sample surface and in 3D was imaged with a dynamic secondary ion mass spectrometry (SIMS) instrument, CAMECA IMS 3f SIMS ion microscope. The beryllium content of shrapnel (~100 ppb) was the same as the trace quantities of beryllium found in aluminum cans. The beryllium content of aluminum foil (~25 ppb) was significantly lower than cans. SIMS imaging analysis revealed beryllium to be distributed in the form of low micron-sized particles and clusters distributed randomly in X-Y-and Z dimensions, and often in association with iron, in the main aluminum matrix of cans. These observations indicate a plausible formation of Be-Fe or Al-Be alloy in the matrix of cans. Further observations were made on fluids (carbonated water) for understanding if trace beryllium in cans leached out and contaminated the food product. A direct comparison of carbonated water in aluminum cans and plastic bottles revealed that beryllium was below the detection limits of the fluorescence detection method (~0.01 ppb). These observations indicate that beryllium present in aluminum matrix was either present in an

  18. Analysis of trace metals (Cu, Cd, Pb, and Fe) in seawater using single batch nitrilotriacetate resin extraction and isotope dilution inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong-Mi [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Boyle, Edward A., E-mail: eaboyle@mit.edu [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Echegoyen-Sanz, Yolanda; Fitzsimmons, Jessica N. [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Zhang Ruifeng [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062 (China); Kayser, Richard A. [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2011-02-07

    A simple and accurate low-blank method has been developed for the analysis of total dissolved copper, cadmium, lead, and iron in a small volume (1.3-1.5 mL per element) of seawater. Pre-concentration and salt-separation of a stable isotope spiked sample are achieved by single batch extraction onto nitrilotriacetate (NTA)-type Superflow chelating resin beads (100-2400 beads depending on the element). Metals are released into 0.1-0.5 M HNO{sub 3}, and trace metal isotope ratios are determined by ICPMS. The benefit of this method compared to our previous Mg(OH){sub 2} coprecipitation method is that the final matrix is very dilute so cone-clogging and matrix sensitivity suppression are minimal, while still retaining the high accuracy of the isotope dilution technique. Recovery efficiencies are sensitive to sample pH, number of resin beads added, and the length of time allowed for sample-resin binding and elution; these factors are optimized for each element to yield the highest recovery. The method has a low procedural blank and high sensitivity sufficient for the analysis of pM-nM open-ocean trace metal concentrations. Application of this method to samples from the Bermuda Atlantic Time-Series Study station provides oceanographically consistent Cu, Cd, Pb, and Fe profiles that are in good agreement with other reliable data for this site. In addition, the method can potentially be modified for the simultaneous analysis of multiple elements, which will be beneficial for the analysis of large number of samples.

  19. Analysis of trace metals (Cu, Cd, Pb, and Fe) in seawater using single batch nitrilotriacetate resin extraction and isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Lee, Jong-Mi; Boyle, Edward A.; Echegoyen-Sanz, Yolanda; Fitzsimmons, Jessica N.; Zhang Ruifeng; Kayser, Richard A.

    2011-01-01

    A simple and accurate low-blank method has been developed for the analysis of total dissolved copper, cadmium, lead, and iron in a small volume (1.3-1.5 mL per element) of seawater. Pre-concentration and salt-separation of a stable isotope spiked sample are achieved by single batch extraction onto nitrilotriacetate (NTA)-type Superflow chelating resin beads (100-2400 beads depending on the element). Metals are released into 0.1-0.5 M HNO 3 , and trace metal isotope ratios are determined by ICPMS. The benefit of this method compared to our previous Mg(OH) 2 coprecipitation method is that the final matrix is very dilute so cone-clogging and matrix sensitivity suppression are minimal, while still retaining the high accuracy of the isotope dilution technique. Recovery efficiencies are sensitive to sample pH, number of resin beads added, and the length of time allowed for sample-resin binding and elution; these factors are optimized for each element to yield the highest recovery. The method has a low procedural blank and high sensitivity sufficient for the analysis of pM-nM open-ocean trace metal concentrations. Application of this method to samples from the Bermuda Atlantic Time-Series Study station provides oceanographically consistent Cu, Cd, Pb, and Fe profiles that are in good agreement with other reliable data for this site. In addition, the method can potentially be modified for the simultaneous analysis of multiple elements, which will be beneficial for the analysis of large number of samples.

  20. Ion trace detection algorithm to extract pure ion chromatograms to improve untargeted peak detection quality for liquid chromatography/time-of-flight mass spectrometry-based metabolomics data.

    Science.gov (United States)

    Wang, San-Yuan; Kuo, Ching-Hua; Tseng, Yufeng J

    2015-03-03

    Able to detect known and unknown metabolites, untargeted metabolomics has shown great potential in identifying novel biomarkers. However, elucidating all possible liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) ion signals in a complex biological sample remains challenging since many ions are not the products of metabolites. Methods of reducing ions not related to metabolites or simply directly detecting metabolite related (pure) ions are important. In this work, we describe PITracer, a novel algorithm that accurately detects the pure ions of a LC/TOF-MS profile to extract pure ion chromatograms and detect chromatographic peaks. PITracer estimates the relative mass difference tolerance of ions and calibrates the mass over charge (m/z) values for peak detection algorithms with an additional option to further mass correction with respect to a user-specified metabolite. PITracer was evaluated using two data sets containing 373 human metabolite standards, including 5 saturated standards considered to be split peaks resultant from huge m/z fluctuation, and 12 urine samples spiked with 50 forensic drugs of varying concentrations. Analysis of these data sets show that PITracer correctly outperformed existing state-of-art algorithm and extracted the pure ion chromatograms of the 5 saturated standards without generating split peaks and detected the forensic drugs with high recall, precision, and F-score and small mass error.

  1. Trace spaces

    DEFF Research Database (Denmark)

    Fajstrup, Lisbeth; Goubault, Eric; Haucourt, Emmanuel

    2012-01-01

    in the interleaving semantics of a concurrent program, but rather some equivalence classes. The purpose of this paper is to describe a new algorithm to compute such equivalence classes, and a representative per class, which is based on ideas originating in algebraic topology. We introduce a geometric semantics...... of concurrent languages, where programs are interpreted as directed topological spaces, and study its properties in order to devise an algorithm for computing dihomotopy classes of execution paths. In particular, our algorithm is able to compute a control-flow graph for concurrent programs, possibly containing...... loops, which is “as reduced as possible” in the sense that it generates traces modulo equivalence. A preliminary implementation was achieved, showing promising results towards efficient methods to analyze concurrent programs, with very promising results compared to partial-order reduction techniques....

  2. Osteoporosis and trace elements

    DEFF Research Database (Denmark)

    Aaseth, J.; Boivin, G.; Andersen, Ole

    2012-01-01

    More than 200 million people are affected by osteoporosis worldwide, as estimated by 2 million annual hip fractures and other debilitating bone fractures (vertebrae compression and Colles' fractures). Osteoporosis is a multi-factorial disease with potential contributions from genetic, endocrine...... in new bone and results in a net gain in bone mass, but may be associated with a tissue of poor quality. Aluminum induces impairment of bone formation. Gallium and cadmium suppresses bone turnover. However, exact involvements of the trace elements in osteoporosis have not yet been fully clarified...

  3. Evaluation of false positive responses by mass spectrometry and ion mobility spectrometry for the detection of trace explosives in complex samples

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C.L., E-mail: clcrawf@sandia.gov; Hill, H.H.

    2013-09-17

    Graphical abstract: -- Highlights: •First study to use (−)SESI-IM-TOFMS to analyze complex mixtures of personal care products. •The study demonstrated, by identifying mobility and mass interferents with explosive signatures, which, if used separately, neither IMS nor MS alone would prevent every false positive for explosives when detected in the presence of a complex sample matrix. •Ingredients in common household cleaning products were shown to either enhance or suppress the ionization of explosives in a SESI-IM-TOFMS analysis. •Mobility separation provided real-time separation of ion species that indicated overlapping isotope peak patterns -- Abstract: Secondary electrospray ionization-ion mobility-time of flight mass spectrometry (SESI-IM-TOFMS) was used to evaluate common household products and food ingredients for any mass or mobility responses that produced false positives for explosives. These products contained ingredients which shared the same mass and mobility drift time ranges as the analyte ions for common explosives. The results of this study showed that the vast array of compounds in these products can cause either mass or mobility false positive responses. This work also found that two ingredients caused either enhanced or reduced ionization of the target analytes. Another result showed that an IMS can provide real-time separation of ion species that impede accurate mass identifications due to overlapping isotope peak patterns. The final result of this study showed that, when mass and mobility values were used to identify an ion, no false responses were found for the target explosives. The wider implication of these results is that the possibility exists for even greater occurrences of false responses from complex mixtures found in common products. Neither IMS nor MS alone can provide 100% assurance from false responses. IMS, due to its low cost, ease of operation, rugged reliability, high sensitivity and tunable selectivity, will remain

  4. Determination of trace Cd, Cu, Fe, Pb and Zn in diesel and gasoline by inductively coupled plasma mass spectrometry after sample clean up with hollow fiber solid phase microextraction system

    Energy Technology Data Exchange (ETDEWEB)

    Nomngongo, Philiswa N.; Ngila, J. Catherine, E-mail: jcngila@uj.ac.za

    2014-08-01

    This study reports a simple and efficient method for the determination of trace Cd, Cu, Fe, Pb and Zn in diesel and gasoline samples by inductively coupled plasma mass spectrometry after matrix removal and analyte pre-concentration using hollow fiber-solid phase microextraction (HF–SPME). The optimization of HF-SPME procedure was carried out using two-level full factorial and central composite designs. Four factors (variables), that are, sample solution pH, acceptor phase amount, extraction time and eluent concentration were optimized. Under the optimized experimental conditions, the precision was ≤ 3% (C = 10 μg L{sup −1}, n = 15), limits of detection and quantification ranged from 0.1 to 0.3 μg L{sup −1} and 0.3–0.9 μg L{sup −1}, respectively, and the maximum preconcentration factor was 30. The HF-SPME method was applied for the determination of trace metals in real gasoline and diesel samples. - Highlights: • Hollow fiber solid phase microextraction of metal ions in diesel and gasoline • Use of hollow fiber-supported sol–gel combined with cation exchange resin • Optimization of HF-SPME using multivariate techniques • Determination of Cd, Cu, Fe, Pb and Zn using ICP–MS • Relatively low LOD and LOQ.

  5. Determination of trace Cd, Cu, Fe, Pb and Zn in diesel and gasoline by inductively coupled plasma mass spectrometry after sample clean up with hollow fiber solid phase microextraction system

    International Nuclear Information System (INIS)

    Nomngongo, Philiswa N.; Ngila, J. Catherine

    2014-01-01

    This study reports a simple and efficient method for the determination of trace Cd, Cu, Fe, Pb and Zn in diesel and gasoline samples by inductively coupled plasma mass spectrometry after matrix removal and analyte pre-concentration using hollow fiber-solid phase microextraction (HF–SPME). The optimization of HF-SPME procedure was carried out using two-level full factorial and central composite designs. Four factors (variables), that are, sample solution pH, acceptor phase amount, extraction time and eluent concentration were optimized. Under the optimized experimental conditions, the precision was ≤ 3% (C = 10 μg L −1 , n = 15), limits of detection and quantification ranged from 0.1 to 0.3 μg L −1 and 0.3–0.9 μg L −1 , respectively, and the maximum preconcentration factor was 30. The HF-SPME method was applied for the determination of trace metals in real gasoline and diesel samples. - Highlights: • Hollow fiber solid phase microextraction of metal ions in diesel and gasoline • Use of hollow fiber-supported sol–gel combined with cation exchange resin • Optimization of HF-SPME using multivariate techniques • Determination of Cd, Cu, Fe, Pb and Zn using ICP–MS • Relatively low LOD and LOQ

  6. High-throughput trace analysis of explosives in water by laser diode thermal desorption/atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Badjagbo, Koffi; Sauvé, Sébastien

    2012-07-03

    Harmful explosives can accumulate in natural waters in the long term during their testing, usage, storage, and dumping and can pose a health risk to humans and the environment. For the first time, attachment of small anions to neutral molecules in laser diode thermal desorption/atmospheric pressure chemical ionization was systematically investigated for the direct determination of trace nitroaromatics, nitrate esters, and nitramine explosives in water. Using ammonium chloride as an additive improved the instrument response for all the explosives tested and promoted the formation of several characteristic adduct ions. The method performs well achieving good linearity over at least 2 orders of magnitude, with coefficients of determination greater than 0.995. The resulting limits of detection are in the range of 0.009-0.092 μg/L. River water samples were successfully analyzed by the proposed method with accuracy in the range of 96-98% and a response time of 15 s, without any further pretreatment or chromatographic separation.

  7. Next generation offline approaches to trace organic compound speciation: Approaching comprehensive speciation with soft ionization and very high resolution tandem mass spectrometry

    Science.gov (United States)

    Khare, P.; Marcotte, A.; Sheu, R.; Ditto, J.; Gentner, D. R.

    2017-12-01

    Intermediate- and semi-volatile organic compounds (IVOCs and SVOCs) have high secondary organic aerosol (SOA) yields, as well as significant ozone formation potentials. Yet, their emission sources and oxidation pathways remain largely understudied due to limitations in current analytical capabilities. Online mass spectrometers are able to collect real time data but their limited mass resolving power renders molecular level characterization of IVOCs and SVOCs from the unresolved complex mixture unfeasible. With proper sampling techniques and powerful analytical instrumentation, our offline tandem mass spectrometry (i.e. MS×MS) techniques provide molecular-level and structural identification over wide polarity and volatility ranges. We have designed a novel analytical system for offline analysis of gas-phase SOA precursors collected on custom-made multi-bed adsorbent tubes. Samples are desorbed into helium via a gradual temperature ramp and sample flow is split equally for direct-MS×MS analysis and separation via gas chromatography (GC). The effluent from GC separation is split again for analysis via atmospheric pressure chemical ionization quadrupole time-of-flight mass spectrometry (APCI-Q×TOF) and traditional electron ionization mass spectrometry (EI-MS). The compounds for direct-MS×MS analysis are delivered via a transfer line maintained at 70ºC directly to APCI-Q×TOF, thus preserving the molecular integrity of thermally-labile, or other highly-reactive, organic compounds. Both our GC-MS×MS and direct-MS×MS analyses report high accuracy parent ion masses as well as information on molecular structure via MS×MS, which together increase the resolution of unidentified complex mixtures. We demonstrate instrument performance and present preliminary results from urban atmospheric samples collected from New York City with a wide range of compounds including highly-functionalized organic compounds previously understudied in outdoor air. Our work offers new

  8. Inductively coupled plasma – Tandem mass spectrometry (ICP-MS/MS): A powerful and universal tool for the interference-free determination of (ultra)trace elements – A tutorial review

    Energy Technology Data Exchange (ETDEWEB)

    Balcaen, Lieve; Bolea-Fernandez, Eduardo [Ghent University, Department of Analytical Chemistry, Krijgslaan 281-S12, B-9000 Ghent (Belgium); Resano, Martín [University of Zaragoza, Department of Analytical Chemistry, Pedro Cerbuna 12, E-50009 Zaragoza (Spain); Vanhaecke, Frank, E-mail: Frank.Vanhaecke@UGent.be [Ghent University, Department of Analytical Chemistry, Krijgslaan 281-S12, B-9000 Ghent (Belgium)

    2015-09-24

    This paper is intended as a tutorial review on the use of inductively coupled plasma – tandem mass spectrometry (ICP-MS/MS) for the interference-free quantitative determination and isotope ratio analysis of metals and metalloids in different sample types. Attention is devoted both to the instrumentation and to some specific tools and procedures available for advanced method development. Next to the more typical reaction gases, e.g., H{sub 2}, O{sub 2} and NH{sub 3}, also the use of promising alternative gases, such as CH{sub 3}F, is covered, and the possible reaction pathways with those reactive gases are discussed. A variety of published applications relying on the use of ICP-MS/MS are described, to illustrate the added value of tandem mass spectrometry in (ultra)trace analysis. - Highlights: • First review on tandem ICP-mass spectrometry (ICP-MS/MS). • Clear description of operating principles of ICP-MS/MS. • Description on how to make use of product ion scans, precursor ion scans and neutral gain scans in method development. • Overview of applications published so far.

  9. Inductively coupled plasma – Tandem mass spectrometry (ICP-MS/MS): A powerful and universal tool for the interference-free determination of (ultra)trace elements – A tutorial review

    International Nuclear Information System (INIS)

    Balcaen, Lieve; Bolea-Fernandez, Eduardo; Resano, Martín; Vanhaecke, Frank

    2015-01-01

    This paper is intended as a tutorial review on the use of inductively coupled plasma – tandem mass spectrometry (ICP-MS/MS) for the interference-free quantitative determination and isotope ratio analysis of metals and metalloids in different sample types. Attention is devoted both to the instrumentation and to some specific tools and procedures available for advanced method development. Next to the more typical reaction gases, e.g., H_2, O_2 and NH_3, also the use of promising alternative gases, such as CH_3F, is covered, and the possible reaction pathways with those reactive gases are discussed. A variety of published applications relying on the use of ICP-MS/MS are described, to illustrate the added value of tandem mass spectrometry in (ultra)trace analysis. - Highlights: • First review on tandem ICP-mass spectrometry (ICP-MS/MS). • Clear description of operating principles of ICP-MS/MS. • Description on how to make use of product ion scans, precursor ion scans and neutral gain scans in method development. • Overview of applications published so far.

  10. Trace detection of organic compounds in complex sample matrixes by single photon ionization ion trap mass spectrometry: real-time detection of security-relevant compounds and online analysis of the coffee-roasting process.

    Science.gov (United States)

    Schramm, Elisabeth; Kürten, Andreas; Hölzer, Jasper; Mitschke, Stefan; Mühlberger, Fabian; Sklorz, Martin; Wieser, Jochen; Ulrich, Andreas; Pütz, Michael; Schulte-Ladbeck, Rasmus; Schultze, Rainer; Curtius, Joachim; Borrmann, Stephan; Zimmermann, Ralf

    2009-06-01

    An in-house-built ion trap mass spectrometer combined with a soft ionization source has been set up and tested. As ionization source, an electron beam pumped vacuum UV (VUV) excimer lamp (EBEL) was used for single-photon ionization. It was shown that soft ionization allows the reduction of fragmentation of the target analytes and the suppression of most matrix components. Therefore, the combination of photon ionization with the tandem mass spectrometry (MS/MS) capability of an ion trap yields a powerful tool for molecular ion peak detection and identification of organic trace compounds in complex matrixes. This setup was successfully tested for two different applications. The first one is the detection of security-relevant substances like explosives, narcotics, and chemical warfare agents. One test substance from each of these groups was chosen and detected successfully with single photon ionization ion trap mass spectrometry (SPI-ITMS) MS/MS measurements. Additionally, first tests were performed, demonstrating that this method is not influenced by matrix compounds. The second field of application is the detection of process gases. Here, exhaust gas from coffee roasting was analyzed in real time, and some of its compounds were identified using MS/MS studies.

  11. On-line immunoaffinity column-liquid chromatography-tandem mass spectrometry method for trace analysis of diuron in wastewater treatment plant effluent sample.

    Science.gov (United States)

    Zhang, Xiuli; Martens, Dieter; Krämer, Petra M; Kettrup, Antonius A; Liang, Xinmiao

    2006-11-10

    An on-line immunoaffinity column with liquid chromatography/tandem mass spectrometry (IAC-LC-MS/MS) method for the determination of diuron in water matrices was described. This method used a sol-gel immunoaffinity column (20 mm x 4 mm I.D.) for on-line sample cleanup and enrichment, a monolithic analytical column (100 mm x 4.6 mm I.D.) for separation, and a triple quadrupole mass spectrometer for quantitation. The major challenges for the on-line set-up were discussed. The optimized on-line protocol was emphasized by the fact that low limit of quantitation (LOQ) of 1.0 ng/L was achieved with only 2.5-mL sample. In addition, a satisfactory accuracy ( approximately 90% of recovery) and precision (effect, the on-line IAC-LC-MS/MS analysis method can reliably determine diuron in wastewater treatment plant effluent sample.

  12. Ultra-trace determination of iodine in sediments and biological material using UV photochemical generation-inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Grinberg, Patricia [Institute for National Measurements Standards, National Research Council Canada, Ottawa, Ontario, K1A 0R6 (Canada)], E-mail: patricia.grinberg@nrc.ca; Sturgeon, Ralph E. [Institute for National Measurements Standards, National Research Council Canada, Ottawa, Ontario, K1A 0R6 (Canada)

    2009-03-15

    Several sample preparation techniques have been evaluated for the determination of iodine using UV-photochemical generation-quadrupole inductively coupled plasma mass spectrometry. Thermal decomposition of samples at 1000 {sup o}C followed by capture of the liberated iodine in dilute acetic acid permitted subsequent UV-photochemical generation of a volatile iodine species that serves to enhance sensitivity 25-fold over conventional solution nebulization, delivering reagent blank detection limits of 8.75 pg g{sup -1127}I and 0.075 pg g{sup -1129}I for solid samples (400 mg test mass). The methodology was validated through determination of total iodine in several Standard Reference Materials, including NIST 1572 Citrus leaves, NIST 1549 Non-fat milk powder, NIST 1566a Oyster tissue and NIST 2709 San Joaquin Soil. Liberation of iodine from samples and its collection as well as photochemical generation were quantitative, permitting calibration to be achieved using standards prepared in dilute acetic acid.

  13. Microwave plasma ion sources for selected ion flow tube mass spectrometry: Optimizing their performance and detection limits for trace gas analysis

    Czech Academy of Sciences Publication Activity Database

    Španěl, Patrik; Dryahina, Kseniya; Smith, D.

    2007-01-01

    Roč. 267, 1-3 (2007), s. 117-124 ISSN 1387-3806 R&D Projects: GA ČR GA202/06/0776 Institutional research plan: CEZ:AV0Z40400503 Keywords : microwave plasma ion source * selected ion flow tube mass spectrometry * SIFT-MS * breath analysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.411, year: 2007

  14. Analysis of biogenic carbonates by inductively coupled plasma-mass spectrometry (ICP-MS). Flow injection on-line solid-phase preconcentration for trace element determination in fish otoliths.

    Science.gov (United States)

    Arslan, Z; Paulson, A J

    2002-04-01

    The aragonite deposits within the ear bones (otoliths) of teleost fish retain a chemical signal reflecting the life history of fish (similar to rings of trees) and the nature of fish habitats. Otoliths dissolved in acid solutions contain high concentrations of calcium and a variety of proteins. Elimination of matrix salts and organic interferences during preconcentration is essential for accurate determination of trace elements in otolith solutions by inductively coupled plasma-quadrupole mass spectrometry. An iminodiacetate-based chelating resin (Toyopearl AF-Chelate 650 M) has been used for on-line preconcentration and matrix separation for the determination of 31 transition and rare elements. Successful preconcentration of the elements was achieved at pH 5 by on-line buffering, except Mn which required pH 8.8. Sample solutions were loaded on to the column for 1 min at 3.2 mL min(-1), and then eluted directly into the mass spectrometer with 4% v/v nitric acid. This procedure enabled up to 25-fold preconcentration with successful removal of the calcium matrix. The effect of heat-assisted oxidation with concentrated nitric acid was investigated to eliminate the organic matrix. It was found that heating to dryness after dissolution and further mineralization with the acid significantly improved the retention of the transition elements. The method was validated by analysis of a certified reference material produced from saggittal otoliths of emperor snapper ( Lutjanus sebae), and then applied to the determination of trace metal concentrations in juvenile bluefin tuna ( Thunnus thynnus) from the Western Pacific Ocean.

  15. Planetary Nebulae and their parent stellar populations. Tracing the mass assembly of M87 and Intracluster light in the Virgo cluster core

    Science.gov (United States)

    Arnaboldi, Magda; Longobardi, Alessia; Gerhard, Ortwin

    2016-08-01

    The diffuse extended outer regions of galaxies are hard to study because they are faint, with typical surface brightness of 1% of the dark night sky. We can tackle this problem by using resolved star tracers which remain visible at large distances from the galaxy centers. This article describes the use of Planetary Nebulae as tracers and the calibration of their properties as indicators of the star formation history, mean age and metallicity of the parent stars in the Milky Way and Local Group galaxies. We then report on the results from a deep, extended, planetary nebulae survey in a 0.5 deg2 region centered on the brightest cluster galaxy NGC 4486 (M87) in the Virgo cluster core, carried out with SuprimeCam@Subaru and FLAMES-GIRAFFE@VLT. Two planetary nebulae populations are identified out to 150 kpc distance from the center of M87. One population is associated with the M87 halo and the second one with the intracluster light in the Virgo cluster core. They have different line-of-sight velocity and spatial distributions, as well as different planetary nebulae specific frequencies and luminosity functions. The intracluster planetary nebulae in the surveyed region correspond to a luminosity of four times the luminosity of the Large Magellanic Cloud. The M87 halo planetary nebulae trace an older, more metal-rich, parent stellar population. A substructure detected in the projected phase-space of the line-of-sight velocity vs. major axis distance for the M87 halo planetary nebulae provides evidence for the recent accretion event of a satellite galaxy with luminosity twice that of M33. The satellite stars were tidally stripped about 1 Gyr ago, and reached apocenter at a major axis distance of 60-90 kpc from the center of M87. The M87 halo is still growing significantly at the distances where the substructure is detected.

  16. Determination of trace sulfur in biodiesel and diesel standard reference materials by isotope dilution sector field inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Amais, Renata S. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, São Carlos, SP (Brazil); Long, Stephen E. [Chemical Sciences Division, National Institute of Standards and Technology, Charleston, SC (United States); Nóbrega, Joaquim A. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, São Carlos, SP (Brazil); Christopher, Steven J., E-mail: steven.christopher@nist.gov [Chemical Sciences Division, National Institute of Standards and Technology, Charleston, SC (United States)

    2014-01-02

    Graphical abstract: -- Highlights: •Sulfur mass fractions are measured below 10 mg kg{sup −1} in diesel fuel materials. •SF-ICP-MS resolves molecular interferences, including oxygen and sulfur hydrides. •A detection limit of 0.7 mg kg{sup −1} (in the fuel sample) was obtained. -- Abstract: A method is described for quantification of sulfur at low concentrations on the order of mg kg{sup −1} in biodiesel and diesel fuels using isotope dilution and sector field inductively coupled plasma mass spectrometry (ID-SF-ICP-MS). Closed vessel microwave-assisted digestion was employed using a diluted nitric acid and hydrogen peroxide decomposition medium to reduce sample dilution volumes. Medium resolution mode was employed to eliminate isobaric interferences at {sup 32}S and {sup 34}S related to polyatomic phosphorus and oxygen species, and sulfur hydride species. The method outlined yielded respective limits of detection (LOD) and limits of quantification (LOQ) of 0.7 mg kg{sup −1} S and 2.5 mg kg{sup −1} S (in the sample). The LOD was constrained by instrument background counts at {sup 32}S but was sufficient to facilitate value assignment of total S mass fraction in NIST SRM 2723b Sulfur in Diesel Fuel Oil at 9.06 ± 0.13 mg kg{sup −1}. No statistically significant difference at a 95% confidence level was observed between the measured and certified values for certified reference materials NIST SRM 2773 B100 Biodiesel (Animal-Based), CENAM DRM 272b and NIST SRM 2723a Sulfur in Diesel Fuel Oil, validating method accuracy.

  17. The Transport of Close-In Fallout Plutonium in the Northwest Pacific Ocean: Tracing the Water Mass Movement Using {sup 240}Pu/{sup 239}Pu Atom Ratio

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Han [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Hong, Gi-Hoon; Suk, Moon-Sik [Korea Ocean Research and Development Institute, Seoul (Korea, Republic of); Gastaud, J. [International Atomic Energy Agency, Marine Environment Laboratory (Monaco); La Rosa, J. [National Institute of Standards and Technology, Ionizing Radiation Division, Gaithersburg, Maryland (United States); Kim, Chul-Soo [Environmental Laboratories, International Atomic Energy Agency, Seibersdorf (Austria); Wyse, E. [New Brunswick Laboratory Argonne, IL (United States); Povinec, P. P. [Comenius University, Faculty of Mathematics and Physics, Bratislava (Slovakia)

    2013-07-15

    {sup 240}Pu/{sup 239}Pu atom ratios in seawater and surface sediment collected from the northwest (NW) Pacific Ocean from 1992 to 1997 were determined using ICP-sector field mass spectrometry (ICP-MS). In whole water columns, the atom ratios of {sup 240}Pu/{sup 239}Pu were higher than the global fallout ratio (0.18). It is noted that the atom ratios of {sup 240}Pu/2{sup 39}Pu in the seawater increase with depth. Such elevated {sup 240}Pu/{sup 239}Pu atom ratios indicate that the close-in fallout plutonium isotopes originating from the Pacific Proving Grounds (PPGs) due to the U.S. tests are prevailing in the seawater in the NW Pacific Ocean. However, the {sup 240}Pu/{sup 239}Pu atom ratios in the surface sediment from the NW Pacific Ocean varied with the sampling locations. As a consequence, this study will provide the information that the water mass along with the current plays a key role in driving the distribution of Pu and in transporting Pu from the PPGs to the far eastern marginal sea in the NW Pacific Ocean. (author)

  18. A new HF-resistant tandem spray chamber for improved determination of trace elements and Pb isotopes using inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Krachler, Michael; Rausch, Nicole; Feuerbacher, Helmut; Klemens, Patrick

    2005-01-01

    The use of a new HF-resistant tandem spray chamber arrangement consisting of a cyclonic spray chamber and a Scott-type spray chamber made from PFA and PEEK provides a straightforward approach for improving the performance of inductively coupled-mass spectrometry (ICP-MS). The characteristics of the tandem spray chamber were critically evaluated against a PEEK cyclonic and a PFA Scott-type spray chamber, respectively. Sensitivity across the entire mass range was increased by about three times compared to the conventional setup utilizing only one spray chamber. Precision of the results, especially at low signal intensities, improved by 160% and 31% compared to the cyclonic and Scott-type spray chamber, respectively. Using the tandem spray chamber, the oxide formation rate was lowered by about 50%. Signals as low as 30 counts could be determined under routine measurement conditions with a RSD of 2.4% thus allowing to precisely quantify small concentration differences at the ng l -1 concentration level. The excellent precision (0.02-0.07%) of 206 Pb / 207 Pb and 206 Pb / 208 Pb ratios determined in pore water samples was rather limited by the instrumental capabilities of the single collector ICP-MS instrument than by the performance of the tandem spray chamber

  19. Determination of major, minor and trace elements in rock samples by laser ablation inductively coupled plasma mass spectrometry: Progress in the utilization of borate glasses as targets

    International Nuclear Information System (INIS)

    Leite, Tacito Dantas F.; Escalfoni, Rainerio; Fonseca, Teresa Cristina O. da; Miekeley, Norbert

    2011-01-01

    The present work is a continuation of a research study performed at our laboratory aiming at the multielement analysis of rock samples (basalts and shale) by inductively coupled plasma mass spectrometry in combination with laser ablation using borate glasses as analytical targets. Argon, nitrogen-argon mixtures and helium were evaluated as cell gases, the latter confirming its better performance. Different operational parameters of the laser, such as gas flow, energy, focus, scanning speed and sampling frequency were optimized. External calibration was made with standards prepared by fusion of geological reference materials (basalts 688 and BCR-2, obsidian SRM 278, and shale SGR-1) of different mass fractions in the meta-tetra borate matrix. Coefficients of determination (R 2 ) were > 0.99 for 30 elements from o total of 40 determined. Method validation was then performed using additional certified reference materials (BHVO-2, BIR-1, SCo-1) produced as borate targets in a similar way. Accuracies were better than 10% for most of the elements studied and analytical precisions, calculated from the residual standard deviations of calibration curves were, typically, between 6% and 10%. Additionally, the semiquantitative TotalQuant (registered) technique was applied, which gave, within the expected uncertainty for this calibration technique, concordant results when compared to the quantitative external calibration procedure. Both methods were then used for the analysis of marine shale samples, which are of great geological interest in petroleum prospecting.

  20. Potential use of the non-random distribution of N2 and N2O mole masses in the atmosphere as a tool for tracing atmospheric mixing and isotope fractionation processes

    International Nuclear Information System (INIS)

    Well, R.; Langel, R.; Reineking, A.

    2002-01-01

    The variation in the natural abundance of 15 N in atmospheric gas species is often used to determine the mixing of trace gases from different sources. With conventional budget calculations one unknown quantity can be determined if the remaining quantities are known. From 15 N tracer studies in soils with highly enriched 15 N-nitrate a procedure is known to calculate the mixing of atmospheric and soil derived N 2 based on the measurement of the 30/28 and 29/28 ratios in gas samples collected from soil covers. Because of the non-random distribution of the mole masses 30 N 2 , 29 N 2 and 28 N 2 in the mixing gas it is possible to calculate two quantities simultaneously, i.e. the mixing ratio of atmospheric and soil derived N 2 , and the isotopic signature of the soil derived N 2 . Routine standard measurements of laboratory air had suggested a non-random distribution of N 2 -mole masses. The objective of this study was to investigate and explain the existence of non-random distributions of 15 N 15 N, 14 N 15 N and 14 N 14 N in N 2 and N 2 O in environmental samples. The calculation of theoretical isotope data resulting from hypothetical mixing of two sources differing in 15 N natural abundance demonstrated, that the deviation from an ideal random distribution of mole masses is not detectable with the current precision of mass spectrometry. 15 N-analysis of N 2 or N 2 O was conducted with randomised and non-randomised replicate samples of different origin. 15 N abundance as calculated from 29/28 ratios were generally higher in randomised samples. The differences between the treatments ranged between 0.05 and 0.17 δper mille 15 N. It was concluded that the observed randomisation effect is probably caused by 15 N 15 N fractionation during environmental processes. (author)

  1. Dissolved rare earth elements in the central-western sector of the Ross Sea, Southern Ocean: Geochemical tracing of seawater masses.

    Science.gov (United States)

    Turetta, Clara; Barbaro, Elena; Capodaglio, Gabriele; Barbante, Carlo

    2017-09-01

    The present essay contributes to the existing literature on rare earth elements (REEs) in the southern hemisphere by presenting the first data, to our knowledge, on the vertical profiles of dissolved REEs in 71 samples collected in the central-western sector of the Ross Sea (Southern Ocean-SO). The REEs were measured in the water samples collected during the 2002-2003 and 2005-2006 austral summers. 4 samples were collected and analysed in the framework of a test experiment, as part of the WISSARD Project (Whillans Ice Stream Subglacial Access Research Drilling). Our results show significant differences between the REE patterns of the main water masses present in the SO: we could observe specific signature in the High Salinity Shelf Water (HSSW), Ice Shelf Water (ISW) and Low Salinity Shelf Water (LSSW). A significant increase in Terbium (Tb) concentration was observed in the HSSW and ISW, the two principal water masses contributing to the formation of Antarctic Bottom Water (AABW) in the Ross Sea area, and in LSSW. Some of the HSSW samples show enrichment in Neodymium (Nd). Dissolved REE could therefore be used as tracers to understand the deep circulation of the SO (Pacific sector). We hypothesize that: (I) the characteristic dissolved REE pattern may derive from the composition of source area and from the hydrothermal activity of the central-western area of the Ross Sea; (II) the Tb anomaly observed in the AABW on the South Australian platform could be partially explained by the contribution of AABW generated in the Ross Sea region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Simultaneous quantification of four native estrogen hormones at trace levels in human cerebrospinal fluid using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Nguyen, Hien P; Li, Li; Gatson, Joshua W; Maass, David; Wigginton, Jane G; Simpkins, James W; Schug, Kevin A

    2011-03-25

    Estrogens are known to exhibit neuroprotective effects on the brain. Their importance in this regard and in others has been emphasized in many recent studies, which increases the need to develop reliable analytical methods for the measurement of estrogen hormones. A heart-cutting two-dimensional liquid chromatography separation method coupled with electrospray ionization-tandem mass spectrometry (ESI-MS/MS) has been developed for simultaneous measurement of four estrogens, including estriol (E3), estrone (E1), 17β-estradiol (17β-E2), and 17α-estradiol (17α-E2), in human cerebrospinal fluid (CSF). The method was based on liquid-liquid extraction and derivatization of estrogens with dansyl chloride to enhance the sensitivity of ESI-based detection in conjunction with tandem mass spectrometry. Dansylated estriol and estrone were separated in the first dimension by an amide-C18 column, while dansylated 17β- and 17α-estradiol were resolved on the second dimension by two C18 columns (175 mm total length) connected in series. This is the first report of a method for simultaneous quantification of all four endogenous estrogen compounds in their dansylated form. The detection limits for E1, 17α-E2, 17β-E2, and E3 were 19, 35, 26, and 61pg/mL, respectively. Due to matrix effects, validation and calibration was carried out in charcoal-stripped CSF. The precision and accuracy were more than 86% for the two E2 compounds and 79% for E1 and E3 while the extraction recovery ranged from 91% to 104%. The method was applied to measure estrogens obtained in a clinical setting, from the CSF of ischemic trauma patients. While 17β-estradiol was present at a significant level in the CSF of some samples, other estrogens were present at lower levels or were undetectable. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Analysis of humic colloid borne trace elements by flow field-flow fractionation, gel permeation chromatography and icp-mass spectrometry

    International Nuclear Information System (INIS)

    Ngo, Manh Thang; Beck, H.P; Geckeis, H.; Kim, J.I.

    1999-01-01

    Groundwater samples containing aquatic humic substances are analyzed by flow field- flow fractionation (FFFF) and gel permeation chromatography (GPC). Natural concentrations of U, Th and rare earth elements (REE) in a size-fractionated groundwater sample are analyzed by on-line coupling of inductively coupled plasma-mass spectrometry (ICP-MS) to either FFFF or GPC. The uranium, thorium, and REE are found to be quantitatively attached to colloidal species in the investigated groundwater sample. Their distribution in different colloid size fractions, however, is quite heterogeneous. Both, FFFF and GPC reveal that Th and REE are preferentially located in the size fraction > 50 kDalton. U is also attached to low molecular weight humic acid, similar to Fe and Al. This finding could be qualitatively reproduced by sequential ultrafiltration. The results are interpreted in terms of different binding mechanisms for the individual elements in the heterogeneous humic macromolecules. The inclusion of actinides into larger aggregates of aquatic humic acid might explain the considerable kinetic hindrance of actinide-humic acid dissociation reactions described in the literature. (authors)

  4. Trace analysis of selected hormones and sterols in river sediments by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry.

    Science.gov (United States)

    Matić, Ivana; Grujić, Svetlana; Jauković, Zorica; Laušević, Mila

    2014-10-17

    In this paper, development and optimization of new LC-MS method for determination of twenty selected hormones, human/animal and plant sterols in river sediments were described. Sediment samples were prepared using ultrasonic extraction and clean up with silica gel/anhydrous sodium sulphate cartridge. Extracts were analyzed by liquid chromatography-linear ion trap-tandem mass spectrometry, with atmospheric pressure chemical ionization. The optimized extraction parameters were extraction solvent (methanol), weight of the sediment (2 g) and time of ultrasonic extraction (3× 10 min). Successful chromatographic separation of hormones (estriol and estrone, 17α- and 17β-estradiol) and four human/animal sterols (epicoprostanol, coprostanol, α-cholestanol and β-cholestanol) that have identical fragmentation reactions was achieved. The developed and optimized method provided high recoveries (73-118%), low limits of detection (0.8-18 ng g(-1)) and quantification (2.5-60 ng g(-1)) with the RSDs generally lower than 20%. Applicability of the developed method was confirmed by analysis of six river sediment samples. A widespread occurrence of human/animal and plant sterols was found. The only detected hormone was mestranol in just one sediment sample. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Structure revision of hupehensis saponin F and G and characterization of new trace triterpenoid saponins from Anemone hupehensis by tandem electrospray ionization mass spectrometry.

    Science.gov (United States)

    Li, Fu; Liu, Xin; Tang, Minghai; Chen, Bin; Ding, Lisheng; Chen, Lijuan; Wang, Mingkui

    2012-05-15

    Electrospray ionization ion-trap tandem mass spectrometry (ESI-MS(n)) was first employed for reinvestigating the structures of hupehensis saponin F and G previously isolated from Anemone hupehensis in our lab. Hupehensis saponin G was determined to contain one more trisaccharide unit (Rha-(1→4)-Glc-(1→6)-Glc-), not a glucose residue, than saponin F based on their molecular weights deduced from their [M+Na](+) ions in ESI-MS spectra. The (2,4)A(4α)-ion at m/z 551.3 formed by retro-Diels-Alder (RDA) rearrangement in positive mode illustrated that the C-28 sugar chains of the two saponins were composed of trisaccharide repeating moieties with (1→4) linkages rather than (1→3) linkages. The interpretation of 2D-NMR spectra of the two compounds also confirmed the results obtained by ESI-MS(n). Moreover, from the water soluble part of A. hupehensis, two novel triterpene saponins were tentatively characterized to contain 4 and 5 (1→4)-linked above trisaccharide repeating moieties at C-28 position according to their ESI-MS(n) behaviors, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Ultra trace determination of 31 pesticides in water samples by direct injection-rapid resolution liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Díaz, Laura; Llorca-Pórcel, Julio; Valor, Ignacio

    2008-08-22

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for the detection of pesticides in tap and treated wastewater was developed and validated according to the ISO/IEC 17025:1999. Key features of this method include direct injection of 100 microL of sample, an 11 min separation by means of a rapid resolution liquid chromatography system with a 4.6 mm x 50 mm, 1.8 microm particle size reverse phase column and detection by electrospray ionization (ESI) MS-MS. The limits of detection were below 15 ng L(-1) and correlation coefficients for the calibration curves in the range of 30-2000 ng L(-1) were higher than 0.99. Precision was always below 20% and accuracy was confirmed by external evaluation. The main advantages of this method are direct injection of sample without preparative procedures and low limits of detection that fulfill the requirements established by the current European regulations governing pesticide detection.

  7. Trace analysis of pesticides in paddy field water by direct injection using liquid chromatography-quadrupole-linear ion trap-mass spectrometry.

    Science.gov (United States)

    Pareja, Lucía; Martínez-Bueno, M J; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, A R

    2011-07-29

    A multiresidue method was developed for the quantification and confirmation of 70 pesticides in paddy field water. After its filtration, water was injected directly in a liquid chromatograph coupled to a hybrid triple quadrupole-linear ion trap-mass spectrometer (QqLIT). The list of target analytes included organophosphates, phenylureas, sulfonylureas, carbamates, conazoles, imidazolinones and others compounds widely used in different countries where rice is cropped. Detection and quantification limits achieved were in the range from 0.4 to 80 ng L(-1) and from 2 to 150 ng L(-1), respectively. Correlation coefficients for the calibration curves in the range 0.1-50 μg L(-1) were higher than 0.99 except for diazinon (0.1-25 μg L(-1)). Only 9 pesticides presented more than 20% of signal suppression/enhancement, no matrix effect was observed in the studied conditions for the rest of the target pesticides. The method developed was used to investigate the occurrence of pesticides in 59 water samples collected in paddy fields located in Spain and Uruguay. The study shows the presence of bensulfuron methyl, tricyclazole, carbendazim, imidacloprid, tebuconazole and quinclorac in a concentration range from 0.08 to 7.20 μg L(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Microwave dissolution of plant tissue and the subsequent determination of trace lanthanide and actinide elements by inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Alvarado, J.S.; Neal, T.J.; Smith, L.L.; Erickson, M.D.

    1997-01-01

    Recently there has been much concern with the ability of plants to uptake heavy metals from their surroundings. With the development of instrumental techniques with low detection limits such as inductively coupled plasma-mass spectrometry (ICP-MS), attention is shifting toward achieving faster and more elegant ways of oxidizing the organic material inherent in environmental samples. Closed-vessel microwave dissolution was compared with conventional methods for the determination of concentrations of cerium, samarium, europium, terbium, uranium and thorium in a series of samples from the National Institute of Standards and Technology and from fields in Idaho. The ICP-MS technique exhibited detection limits in parts-per-trillion and linear calibration plots over three orders of magnitude for the elements under study. The results obtained by using nitric acid and hydrogen peroxide in a microwave digestion system for the analysis of reference materials showed close agreement with the accepted values. These values were compared with results obtained from dry- and wet-ashing procedures. The findings from an experiment comparing radiometric techniques for the determination of actinide elements to ICP-MS are reported

  9. Bulk derivatization and direct injection of human cerebrospinal fluid for trace-level quantification of endogenous estrogens using trap-and-elute liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Fan, Hui; Papouskova, Barbora; Lemr, Karel; Wigginton, Jane G; Schug, Kevin A

    2014-08-01

    Although there are existing methods for determining estrogen in human bodily fluids including blood plasma and serum, very little information is available regarding estrogen levels in human cerebrospinal fluid (CSF), which is critical to assess in studies of neuroprotective functions and diffusion of neuroprotective estrogens across the blood-brain barrier. To address this problem, a liquid chromatography with tandem mass spectrometry method for the simultaneous quantification of four endogenous estrogens (estrone, 17α-estradiol, 17β-estradiol, and estriol) in human CSF was developed. An aliquot (300 μL) of human CSF was bulk derivatized using dansyl chloride in the sample and 10 μL was directly injected onto a restricted-access media trap column for protein removal. No off-line sample extraction or cleanup was needed. The limits of detection of estrone, 17α-estradiol, 17β-estradiol, and estriol were 17, 28, 13, and 30 pg/mL, respectively, which is in the parts-per-trillion regime. The method was then applied to human CSF collected from ischemic trauma patients. Endogenous estrogens were detected and quantified, demonstrating the effectiveness of this method. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Potential of capillary-column-switching liquid chromatography-tandem mass spectrometry for the quantitative trace analysis of small molecules. Application to the on-line screening of drugs in water.

    Science.gov (United States)

    Pitarch, Elena; Hernandez, Felix; ten Hove, Jan; Meiring, Hugo; Niesing, Willem; Dijkman, Ellen; Stolker, Linda; Hogendoorn, Elbert

    2004-03-26

    We have investigated the potential of capillary-column-switching liquid chromatography coupled to tandem mass spectrometry (cLC-MS-MS) for the quantitative on-line trace analysis of target compounds in aqueous solutions. The technical design of the nano-scale cLC system developed at our Institute for peptide and protein identification has been tested and evaluated for the direct trace analysis of drugs in water samples. Sulphametoxazole, bezafibrate, metoprolol, carbamazepine and bisoprolol occurring frequently in Dutch waters, were selected as test compounds. Adequate conditions for trapping, elution and MS-MS detection were investigated by employing laboratory made 200 microm i.d. capillary columns packed with 5 microm aqua C18 material. In the final cLC-MS-MS conditions, a 1 cm length trapping column and a 4 cm length analytical column were selected. Under these conditions, the target compounds could be directly determined in water down to a level of around 50 ng/l employing only 25 microl of water sample. Validation was done by recovery experiments in ground-, surface- and drinking-water matrices as well as by the analysis of water samples with incurred residues and previously analyzed with a conventional procedure involving off-line solid-phase extraction and narrow-bore LC with MS-MS detection. The new methodology provided recoveries (50-500 ng/l level) between 50 and 114% with RSDs (n = 3, each level) below 20% for most of the compounds. Despite the somewhat less analytical performance in comparison to the conventional procedure, the on-line approach of the new methodology is very suitable for screening of drugs in aqueous samples.

  11. Epidemic contact tracing via communication traces.

    Directory of Open Access Journals (Sweden)

    Katayoun Farrahi

    Full Text Available Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

  12. Epidemic contact tracing via communication traces.

    Science.gov (United States)

    Farrahi, Katayoun; Emonet, Rémi; Cebrian, Manuel

    2014-01-01

    Traditional contact tracing relies on knowledge of the interpersonal network of physical interactions, where contagious outbreaks propagate. However, due to privacy constraints and noisy data assimilation, this network is generally difficult to reconstruct accurately. Communication traces obtained by mobile phones are known to be good proxies for the physical interaction network, and they may provide a valuable tool for contact tracing. Motivated by this assumption, we propose a model for contact tracing, where an infection is spreading in the physical interpersonal network, which can never be fully recovered; and contact tracing is occurring in a communication network which acts as a proxy for the first. We apply this dual model to a dataset covering 72 students over a 9 month period, for which both the physical interactions as well as the mobile communication traces are known. Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves. Overall, contact tracing via mobile phone communication traces may be a viable option to arrest contagious outbreaks.

  13. Exploiting dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) for sequential determination of trace elements in blood using a dilute-and-shoot procedure

    International Nuclear Information System (INIS)

    Lemos Batista, Bruno; Lisboa Rodrigues, Jairo; Andrade Nunes, Juliana; Oliveira Souza, Vanessa Cristina de; Barbosa, Fernando

    2009-01-01

    Inductively coupled plasma mass spectrometry with quadrupole (q-ICP-MS) and dynamic reaction cell (DRC-ICP-MS) were evaluated for sequential determination of As, Cd, Co, Cr, Cu, Mn, Pb, Se, Tl, V and Zn in blood. The method requires as little as 100 μL of blood. Prior to analysis, samples (100 μL) were diluted 1:50 in a solution containing 0.01% (v/v) Triton X-100 and 0.5% (v/v) nitric acid. The use of the DRC was only mandatory for Cr, Cu, V and Zn. For the other elements the equipment may be operated in a standard mode (q-ICP-MS). Ammonia was used as reaction gas. Selection of best flow rate of ammonium gas and optimization of the quadrupole dynamic band-pass tuning parameter (RPq) were carried out, using a ovine base blood for Cr and V and a synthetic matrix solution (SMS) for Zn and Cu diluted 1:50 and spiked to contain 1 μg L -1 of each element. Method detection limits (3 s) for 75 As, 114 Cd, 59 Co, 51 Cr, 63 Cu 55 Mn, 208 Pb, 82 Se, 205 Tl, 51 V, and 64 Zn were 14.0, 3.0, 11.0, 7.0, 280, 9.0, 3.0, 264, 0.7, 6.0 and 800 ng L -1 , respectively. Method validation was accomplished by the analysis of blood Reference Materials produced by the L'Institut National de Sante Publique du Quebec (Canada).

  14. Determination of trace elements in biological samples treated with formic acid by inductively coupled plasma mass spectrometry using a microconcentric nebulizer

    International Nuclear Information System (INIS)

    Tormen, Luciano; Gil, Raul A.; Frescura, Vera L.A.; Dante Martinez, Luis; Curtius, Adilson J.

    2010-01-01

    A simple and fast method for the determination of As, Ba, Cd, Co, Cu, Fe, Ga, Mn, Mo, Ni, Pb, Rb, Se, Sr, Tl, U, V and Zn in biological samples by inductively coupled plasma mass spectrometry (ICP-MS), after sample solubilization with formic acid and introduction by a microconcentric nebulizer, is proposed. The sample is mixed with formic acid, kept at 90 o C for one hour and then diluted with nitric acid aqueous solution to a 50% v/v formic acid and 1% v/v nitric acid final concentrations. The final sample solution flow rate for introduction into the plasma was 30 μL min -1 . The optimized and adopted nebulizer gas flow rate was 0.7 L min -1 and RF power was 800 W. These conditions are very different than those normally used when a conventional nebulizer is employed. Rodhium was used as internal standard. External calibration against aqueous standard solutions, without formic acid, could be used for quantification, except for As, Se and Zn. However, external calibration with 50% formic acid allows the determination of all analytes with high accuracy and it is recommended. The detection limits were between 0.0005 (Tl) and 0.22 mg kg -1 (Fe) and the precision expressed by the relative standard deviations (RSD) were between 0.2% (Sr) and 3.5% (Ga). Accuracy was validated by the analysis of four certified reference biological materials of animal tissues, comparing the results by linear regressions and by the t-test at a 95% confidence level. The recommended procedure avoids plasma instability and carbon deposit on the cones.

  15. Flux Analysis of Free Amino Sugars and Amino Acids in Soils by Isotope Tracing with a Novel Liquid Chromatography/High Resolution Mass Spectrometry Platform.

    Science.gov (United States)

    Hu, Yuntao; Zheng, Qing; Wanek, Wolfgang

    2017-09-05

    Soil fluxomics analysis can provide pivotal information for understanding soil biochemical pathways and their regulation, but direct measurement methods are rare. Here, we describe an approach to measure soil extracellular metabolite (amino sugar and amino acid) concentrations and fluxes based on a 15 N isotope pool dilution technique via liquid chromatography and high-resolution mass spectrometry. We produced commercially unavailable 15 N and 13 C labeled amino sugars and amino acids by hydrolyzing peptidoglycan isolated from isotopically labeled bacterial biomass and used them as tracers ( 15 N) and internal standards ( 13 C). High-resolution (Orbitrap Exactive) MS with a resolution of 50 000 allowed us to separate different stable isotope labeled analogues across a large range of metabolites. The utilization of 13 C internal standards greatly improved the accuracy and reliability of absolute quantification. We successfully applied this method to two types of soils and quantified the extracellular gross fluxes of 2 amino sugars, 18 amino acids, and 4 amino acid enantiomers. Compared to the influx and efflux rates of most amino acids, similar ones were found for glucosamine, indicating that this amino sugar is released through peptidoglycan and chitin decomposition and serves as an important nitrogen source for soil microorganisms. d-Alanine and d-glutamic acid derived from peptidoglycan decomposition exhibited similar turnover rates as their l-enantiomers. This novel approach offers new strategies to advance our understanding of the production and transformation pathways of soil organic N metabolites, including the unknown contributions of peptidoglycan and chitin decomposition to soil organic N cycling.

  16. Ultra-trace determination of gold nanoparticles in environmental water by surfactant assisted dispersive liquid liquid microextraction coupled with electrothermal vaporization-inductively coupled plasma-mass spectrometry

    Science.gov (United States)

    Liu, Ying; He, Man; Chen, Beibei; Hu, Bin

    2016-08-01

    A new method by coupling surfactant assisted dispersive liquid liquid microextraction (SA-DLLME) with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) was proposed for the analysis of gold nanoparticles (AuNPs) in environmental water samples. Effective separation of AuNPs from ionic gold species was achieved by using sodium thiosulphate as a complexing agent. Various experimental parameters affecting SA-DLLME of AuNPs, such as the organic solvent, organic solvent volume, pH of the sample, the kind of surfactant, surfactant concentration, vortex time, speed of centrifugation, centrifugation time, and different coating as well as sizes of AuNPs were investigated carefully. Furthermore, the interference of coexisting ions, dissolved organic matter (DOM) and other metal nanoparticles (NPs) were studied. Under the optimal conditions, a detection limit of 2.2 ng L- 1 and an enrichment factor of 152-fold was achieved for AuNPs, and the original morphology of the AuNPs could be maintained during the extraction process. The developed method was successfully applied for the analysis of AuNPs in environmental water samples, including tap water, the East Lake water, and the Yangtze River water, with recoveries in the range of 89.6-102%. Compared with the established methods for metal NPs analysis, the proposed method has the merits of simple and fast operation, low detection limit, high selectivity, good tolerance to the sample matrix and no digestion or dilution required. It provides an efficient quantification methodology for monitoring AuNPs' pollution in the environmental water and evaluating its toxicity.

  17. Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Ni [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Jiang, Shiuh-Jen, E-mail: sjjiang@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Chen, Yen-Ling [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Sahayam, A.C. [National Centre for Compositional Characterisation of Materials (CCCM), Hyderabad (India)

    2015-02-20

    Highlights: • Determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions in a single run. • Accurate analysis using isotope dilution and standard addition methods. • Vapor generation ICP-MS yielded superior detection limits compared to ETV-ICP-MS. • No sample dissolution increased sample through put. • Analysis of GBW09305 Cosmetic (Cream) reference material for accuracy. - Abstract: A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v L-cysteine, 0.5 μg mL{sup −1} Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng g{sup −1} for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample.

  18. Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions

    International Nuclear Information System (INIS)

    Chen, Wei-Ni; Jiang, Shiuh-Jen; Chen, Yen-Ling; Sahayam, A.C.

    2015-01-01

    Highlights: • Determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions in a single run. • Accurate analysis using isotope dilution and standard addition methods. • Vapor generation ICP-MS yielded superior detection limits compared to ETV-ICP-MS. • No sample dissolution increased sample through put. • Analysis of GBW09305 Cosmetic (Cream) reference material for accuracy. - Abstract: A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v L-cysteine, 0.5 μg mL −1 Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng g −1 for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample

  19. Flux Analysis of Free Amino Sugars and Amino Acids in Soils by Isotope Tracing with a Novel Liquid Chromatography/High Resolution Mass Spectrometry Platform

    Science.gov (United States)

    2017-01-01

    Soil fluxomics analysis can provide pivotal information for understanding soil biochemical pathways and their regulation, but direct measurement methods are rare. Here, we describe an approach to measure soil extracellular metabolite (amino sugar and amino acid) concentrations and fluxes based on a 15N isotope pool dilution technique via liquid chromatography and high-resolution mass spectrometry. We produced commercially unavailable 15N and 13C labeled amino sugars and amino acids by hydrolyzing peptidoglycan isolated from isotopically labeled bacterial biomass and used them as tracers (15N) and internal standards (13C). High-resolution (Orbitrap Exactive) MS with a resolution of 50 000 allowed us to separate different stable isotope labeled analogues across a large range of metabolites. The utilization of 13C internal standards greatly improved the accuracy and reliability of absolute quantification. We successfully applied this method to two types of soils and quantified the extracellular gross fluxes of 2 amino sugars, 18 amino acids, and 4 amino acid enantiomers. Compared to the influx and efflux rates of most amino acids, similar ones were found for glucosamine, indicating that this amino sugar is released through peptidoglycan and chitin decomposition and serves as an important nitrogen source for soil microorganisms. d-Alanine and d-glutamic acid derived from peptidoglycan decomposition exhibited similar turnover rates as their l-enantiomers. This novel approach offers new strategies to advance our understanding of the production and transformation pathways of soil organic N metabolites, including the unknown contributions of peptidoglycan and chitin decomposition to soil organic N cycling. PMID:28776982

  20. Ammonium chloride salting out extraction/cleanup for trace-level quantitative analysis in food and biological matrices by flow injection tandem mass spectrometry.

    Science.gov (United States)

    Nanita, Sergio C; Padivitage, Nilusha L T

    2013-03-20

    A sample extraction and purification procedure that uses ammonium-salt-induced acetonitrile/water phase separation was developed and demonstrated to be compatible with the recently reported method for pesticide residue analysis based on fast extraction and dilution flow injection mass spectrometry (FED-FI-MS). The ammonium salts evaluated were chloride, acetate, formate, carbonate, and sulfate. A mixture of NaCl and MgSO4, salts used in the well-known QuEChERS method, was also tested for comparison. With thermal decomposition/evaporation temperature of salts resulted in negligible ion source residual under typical electrospray conditions, leading to consistent method performance and less instrument cleaning. Although all ammonium salts tested induced acetonitrile/water phase separation, NH4Cl yielded the best performance, thus it was the preferred salting out agent. The NH4Cl salting out method was successfully coupled with FI/MS/MS and tested for fourteen pesticide active ingredients: chlorantraniliprole, cyantraniliprole, chlorimuron ethyl, oxamyl, methomyl, sulfometuron methyl, chlorsulfuron, triflusulfuron methyl, azimsulfuron, flupyrsulfuron methyl, aminocyclopyrachlor, aminocyclopyrachlor methyl, diuron and hexazinone. A validation study was conducted with nine complex matrices: sorghum, rice, grapefruit, canola, milk, eggs, beef, urine and blood plasma. The method is applicable to all analytes, except aminocyclopyrachlor. The method was deemed appropriate for quantitative analysis in 114 out of 126 analyte/matrix cases tested (applicability rate=0.90). The NH4Cl salting out extraction/cleanup allowed expansion of FI/MS/MS for analysis in food of plant and animal origin, and body fluids with increased ruggedness and sensitivity, while maintaining high-throughput (run time=30s/sample). Limits of quantitation (LOQs) of 0.01mgkg(-1) (ppm), the 'well-accepted standard' in pesticide residue analysis, were achieved in >80% of cases tested; while limits of detection

  1. Study of matrix effects on the direct trace analysis of acidic pesticides in water using various liquid chromatographic modes coupled to tandem mass spectrometric detection.

    Science.gov (United States)

    Dijkman, E; Mooibroek, D; Hoogerbrugge, R; Hogendoorn, E; Sancho, J V; Pozo, O; Hernández, F

    2001-08-10

    This study investigated the effects of matrix interferences on the analytical performance of a triple quadrupole mass spectrometric (MS-MS) detector coupled to various reversed-phase liquid chromatographic (LC) modes for the on-line determination of various types of acidic herbicides in water using external calibration for quantification of the analytes tested at a level of 0.4 microg/l. The LC modes included (i) a single-column configuration (LC), (ii) precolumn switching (PC-LC) and (iii) coupled-column LC (LC-LC). As regards detection, electrospray (ESI) and atmospheric pressure chemical ionization (APCI) in both positive (PI) and negative (NI) ionization modes were examined. Salinity and dissolved organic carbon (DOC) were selected as interferences to study matrix effects in this type of analysis. Therefore, Milli-Q and tap water samples both fortified with 12 mg/l DOC and spiked with sulfometuron-methyl, bentazone, bromoxynil, 2-methyl-4-chlorophenoxyacetic acid, and 2-methyl-4-chlorophenoxypropionic acid at a level of about 0.4 microg/l were analyzed with the various LC-MS approaches. Direct sample injection was performed with volumes of 0.25 ml or 2.0 ml on a column of 2.1 mm I.D. or 4.6 mm I.D. for the ESI and APCI modes, respectively. The recovery data were used to compare and evaluate the analytical performance of the various LC approaches. As regards matrix effects, the salinity provided a dramatic decrease in response for early eluting analytes (k value of about 1) when using the LC mode. Both PC-LC and LC-LC efficiently eliminated this problem. The high DOC content hardly effected the responses of analytes in the ESI mode, while in most cases the responses increased when using APCI-MS-MS detection. Of all the tested configurations, LC-LC-ESI-MS-MS with the column combination Discovery C18/ABZ+ was the most favorable as regards elimination of matrix effects and provided reliable quantification of all compounds using external calibration at the tested

  2. Comparison of Gas Chromatography-Mass Spectrometry and Gas Chromatography-Tandem Mass Spectrometry with Electron Ionization and Negative-Ion Chemical Ionization for Analyses of Pesticides at Trace Levels in Atmospheric Samples

    Directory of Open Access Journals (Sweden)

    Renata Raina

    2008-01-01

    Full Text Available A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS in selected ion monitoring (SIM with gas chromatography-tandem mass spectrometry (GC-MS/MS in selected reaction monitoring (SRM mode with both electron ionization (EI and negative-ion chemical ionization (NCI are presented for over 50 pesticides ranging from organochlorines (OCs, organophosphorus pesticides (OPs and pre-emergent herbicides used in the Canadian prairies (triallate, trifluralin, ethalfluralin. The developed GC-EI/SIM, GC-NCI/SIM, and GC-NCI/SRM are suitable for the determination of pesticides in air sample extracts at concentrations <100 pg µL -1 (< 100 pg m -3 in air. No one method could be used to analyze the range of pre-emergent herbicides, OPs, and OCs investigated. In general GC-NCI/SIM provided the lowest method detection limits (MDLs commonly 2.5-10 pg µL -1 along with best confirmation (<25% RSD of ion ratio, while GC-NCI/SRM is recommended for use where added selectivity or confirmation is required (such as parathion-ethyl, tokuthion, carbofenothion. GC-EI/SRM at concentration < 100 pg µL -1 was not suitable for most pesticides. GC-EI/SIM was more prone to interference issues than NCI methods, but gave good sensitivity (MDLs 1-10 pg µL -1 for pesticides with poor NCI response (OPs: sulfotep, phorate, aspon, ethion, and OCs: alachlor, aldrin, perthane, and DDE, DDD, DDT.

  3. Electrothermal vaporisation ICP-mass spectrometry (ETV-ICP-MS) for the determination and speciation of trace elements in solid samples - A review of real-life applications from the author's lab

    Energy Technology Data Exchange (ETDEWEB)

    Vanhaecke, Frank; Resano, Martin; Moens, Luc [Laboratory of Analytical Chemistry, Ghent University, Institute for Nuclear Sciences, Proeftuinstraat 86, 9000 Ghent (Belgium)

    2002-09-01

    The use of electrothermal vaporisation (ETV) from a graphite furnace as a means of sample introduction in inductively coupled plasma mass spectrometry (ICP-MS) permits the direct analysis of solid samples. A multi-step furnace temperature programme is used to separate the vaporisation of the target element(s) and of the matrix components from one another. Sometimes, a chemical modifier is used to enable a higher thermal pre-treatment temperature, by avoiding premature analyte losses (stabilisation) or promoting the selective volatilisation of matrix components. In almost all instances, accurate results can be obtained via external calibration or single standard addition using an aqueous standard solution. Absolute limits of detection are typically 1 pg, which corresponds to 1 ng/g for a typical sample mass of 1 mg. Real-life applications carried out in the author's lab are used to illustrate the utility of this approach. These applications aim at trace element determination in industrial and environmental materials. The industrial materials analysed include different types of plastics - Carilon, polyethylene, poly(ethyleneterephtalate) and polyamide - and photo- and thermographic materials. As samples from environmental origin, plant material, animal tissue and sediments were investigated. Some applications aimed at a multi-element determination, while in other, the content of a single, but often challenging, element (e.g., Si or S) had to be measured. ETV-ICP-MS was also used in elemental speciation studies. Separation of Se-containing proteins was accomplished using polyacrylamide gel electrophoresis (PAGE). Subsequent quantification of the Se content in the protein spots was carried out using ETV-ICP-MS. As the volatilisation of methylmercury and inorganic mercury could be separated from one another with respect to time, no chromatographic or electrophoretic separation procedure was required, but ETV-ICP-MS as such sufficed for Hg speciation in fish tissue

  4. Determination of trace amounts of rare-earth elements in highly pure neodymium oxide by sector field inductively coupled plasma mass spectrometry (ICP-SFMS) and high-performance liquid chromatography (HPLC) techniques

    Science.gov (United States)

    Pedreira, W. R.; Sarkis, J. E. S.; da Silva Queiroz, C. A.; Rodrigues, C.; Tomiyoshi, I. A.; Abrão, A.

    2003-02-01

    Recently rare-earth elements (REE) have received much attention in fields of geochemistry and industry. Rapid and accurate determinations of them are increasingly required as industrial demands expand. Sector field inductively coupled plasma mass spectrometry (ICP-SFMS) with high-performance liquid chromatography (HPLC) has been applied to the determination of REE. HR ICP-MS was used as an element-selective detector for HPLC in highly pure materials. The separation of REE with HPLC helped to avoid erroneous analytical results due to spectral interferences. Sixteen elements (Sc, Y and 14 lanthanides) were determined selectively with the HPLC/ICP-SFMS system using a concentration gradient methods. The detection limits with the HPLC/ICP-SFMS system were about 0.5-10 pg mL-1. The percentage recovery ranged from 90% to 100% for different REE. The %RSD of the methods varying between 2.5% and 4.5% for a set of five (n=5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two highly pure neodymium oxides samples (IPEN and Johnson Matthey Company) were performed. In short, the IPEN's materials which are highly pure (>99.9%) were successfully analyzed without spectral interferences.

  5. Determination of trace amounts of rare-earth elements in highly pure neodymium oxide by sector field inductively coupled plasma mass spectrometry (ICP-SFMS) and high-performance liquid chromatography (HPLC) techniques

    International Nuclear Information System (INIS)

    Pedreira, W.R.; Sarkis, J.E.S.; Silva Queiroz, C.A. da; Rodrigues, C.; Tomiyoshi, I.A.; Abrao, A.

    2003-01-01

    Recently rare-earth elements (REE) have received much attention in fields of geochemistry and industry. Rapid and accurate determinations of them are increasingly required as industrial demands expand. Sector field inductively coupled plasma mass spectrometry (ICP-SFMS) with high-performance liquid chromatography (HPLC) has been applied to the determination of REE. HR ICP-MS was used as an element-selective detector for HPLC in highly pure materials. The separation of REE with HPLC helped to avoid erroneous analytical results due to spectral interferences. Sixteen elements (Sc, Y and 14 lanthanides) were determined selectively with the HPLC/ICP-SFMS system using a concentration gradient methods. The detection limits with the HPLC/ICP-SFMS system were about 0.5-10 pg mL -1 . The percentage recovery ranged from 90% to 100% for different REE. The %RSD of the methods varying between 2.5% and 4.5% for a set of five (n=5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two highly pure neodymium oxides samples (IPEN and Johnson Matthey Company) were performed. In short, the IPEN's materials which are highly pure (>99.9%) were successfully analyzed without spectral interferences

  6. 气相色谱质谱联用法测定液氧中微量的氪和氙%Determination of trace krypton and xenon in liquid oxygen by Gas Chromatography/Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    唐轩; 陈鹰; 吴建军

    2013-01-01

    Trace krypton and xenon was determined by gas chromatography/mass spectrometry with selection ion monitoring mode (SIM). The ions m/z=84 and m/z=132 were chosen as quantitative ion for krypton and xenon respectively. The results show that it is a simple way to implement, rapid detection and good selectivity. The linear relation between the peak area and concentration was excellent within the range of (1.0~100)×10-6 V/V. Meanwhile, the minimum detectable concentration and repeatability was also detected.%利用气相色谱质谱联用技术中的选择离子监测(SIM)方式对液氧中的微量氪气和氙气进行了测定。选择m/z为84的离子作为氪的定量离子、m/z为132的离子作为氙的定量离子。方法简单、快速、选择性好,在浓度为(1.0~100)×10-6 V/V范围内,峰面积与浓度有良好的线性关系。同时考察了方法的最低检测浓度和重复性。

  7. Rapid and effective sample cleanup based on graphene oxide-encapsulated core–shell magnetic microspheres for determination of fifteen trace environmental phenols in seafood by liquid chromatography–tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Sheng-Dong; Chen, Xiao-Hong [Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010 (China); Ningbo Key Laboratory of Poison Research and Control, Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010 (China); Shen, Hao-Yu [Ningbo Institute of Technology, Zhejiang University, Ningbo, Zhejiang 315100 (China); Li, Xiao-Ping [Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010 (China); Ningbo Key Laboratory of Poison Research and Control, Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010 (China); Cai, Mei-Qiang [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); Zhao, Yong-Gang [Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010 (China); Ningbo Key Laboratory of Poison Research and Control, Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010 (China); Jin, Mi-Cong, E-mail: jmcjc@163.com [Key Laboratory of Health Risk Appraisal for Trace Toxic Chemicals of Zhejiang Province, Ningbo Municipal Center for Disease Control and Prevention, Ningbo, Zhejiang 315010 (China); Ningbo Key Laboratory of Poison Research and Control, Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010 (China)

    2016-05-05

    In this study, graphene oxide-encapsulated core–shell magnetic microspheres (GOE-CS-MM) were fabricated by a self-assemble approach between positive charged poly(diallyldimethylammonium) chloride (PDDA)-modified Fe{sub 3}O{sub 4}@SiO{sub 2} and negative charged GO sheets via electrostatic interaction. The as-prepared GOE-CS-MM was carefully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer analysis (VSM), and X-ray photoelectron spectroscopy (XPS), and was used as a cleanup adsorbent in magnetic solid-phase extraction (MSPE) for determination of 15 trace-level environmental phenols in seafood coupled to liquid chromatography–tandem mass spectrometry (LC–MS/MS). The obtained results showed that the GOE-CS-MM exhibited excellent cleanup efficiency and could availably reduce the matrix effect. The cleanup mechanisms were investigated and referred to π–π stacking interaction and hydrogen bond between GOE-CS-MM and impurities in the extracts. Moreover, the extraction and cleanup conditions of GOE-CS-MM toward phenols were optimized in detail. Under the optimized conditions, the limits of detection (LODs) were found to be 0.003–0.06 μg kg{sup −1}, and satisfactory recovery values of 84.8–103.1% were obtained for the tested seafood samples. It was confirmed that the developed method is simple, fast, sensitive, and accurate for the determination of 15 trace environmental phenols in seafood samples. - Highlights: • Novel graphene oxide-encapsulated core-shell magnetic microspheres (GOE-CS-MM) were fabricated by a self-assemble approach. • The as-prepared material GOE-CS-MM exhibited excellent cleanup efficiency and could availably reduce the matrix effect. • The cleanup mechanisms refer to π–π stacking interaction and hydrogen bond. • The developed MSPE–LC–MS/MS method was simple, fast, sensitive and accurate.

  8. Triethylamine-assisted Mg(OH)2 coprecipitation/preconcentration for determination of trace metals and rare earth elements in seawater by inductively coupled plasma mass spectrometry (ICP-MS).

    Science.gov (United States)

    Arslan, Zikri; Oymak, Tulay; White, Jeremy

    2018-05-30

    In this paper, we report an improved magnesium hydroxide, Mg(OH) 2 , coprecipitation method for the determination of 16 trace elements (Al, V, Cr, Mn, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Sb, Sn and Pb) and 18 rare earth elements (REEs), including Sc, Y, U and Th in seawater and estuarine water samples. The procedure involves coprecipitation of the trace elements and REEs on Mg(OH) 2 upon addition of a small volume of triethylamine (TEA) followed by analysis of the dissolved pellet solutions by inductively coupled plasma mass spectrometry (ICP-MS). Three-step sequential coprecipitation was carried out on 10 mL aliquots of seawater to eliminate the matrix ions and to preconcentrate the analytes of interest into a 1 mL final volume. Spike recoveries varied from 85% (Th) to 105% (Y). Calcium (Ca), sodium (Na) and potassium (K) matrices were virtually eliminated from the analysis solutions. Collision reaction interface (CRI) technology utilizing H 2 and He gases was employed to determine its effectiveness in removing the spectral interferences originating from the residual Mg matrix, TEA and plasma gases. H 2 was more effective than He in reducing spectral interferences from TEA and plasma gases. Limits of detection (LODs) ranged from 0.01 ng L -1 (Ho) to 72 ng L -1  (Al). The method was validated by using certified seawater (CASS-4) and estuarine water (SLEW-3) reference materials. Precision for five (n = 5) replicate measurements were between 1.2% (Pr) and 18% (Lu). Fe, Pb, Sn, and Zn impurities in TEA were significant in comparison to the levels in CASS-4 and SLEW-3, while relatively high background signals impacted determinations of low levels of Sc and Th. The effects of these hurdles on precision and accuracy were alleviated by measuring these elements in spiked CASS-4 and SLEW-3. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Comparison of various liquid chromatographic methods involving UV and atmospheric pressure chemical ionization mass spectrometric detection for the efficient trace analysis of phenylurea herbicides in various types of water samples.

    Science.gov (United States)

    van der Heeft, E; Dijkman, E; Baumann, R A; Hogendoorn, E A

    2000-05-19

    The performance of mass spectrometric (MS) detection and UV detection in combination with reversed-phase liquid chromatography without and with the use of coupled column RPLC (LC-LC) has been compared for the trace analysis of phenylurea herbicides in environmental waters. The selected samples of this comparative study originated from an inter-laboratory study. For both detection modes, a 50 mm x 4.6 mm I.D. column and a 100 mm x 4.6 mm I.D. column packed with 3 microm C18 were used as the first (C-1) and second (C-2) column, respectively. Atmospheric pressure chemical ionization mass spectrometry was performed on a magnetic sector instrument. The LC-LC-MS analysis was carried out on-line by means of direct large volume (11.7 ml) injection (LVI). The performance of both on-line (LVI, 4 ml of sample) and off-line LC-LC-UV (244 nm) analysis was investigated. The latter procedure consisted of a solid-phase extraction (SPE) of 250 ml of water sample on a 500 mg C18 cartridge. The comparative study showed that LC-LC-MS is more selective then LC-LC-UV and, in most cases, more sensitive. The LVI-LC-LC-MS approach combines direct quantification and confirmation of most of the analytes down to a level of 0.01 microg/l in water samples in less then 30 min. As regards LC-LC-UV, the off-line method appeared to be a more viable approach in comparison with the on-line procedure. This method allows the screening of phenylurea's in various types of water samples down to a level of at least 0.05 microg/l. On-line analysis with LVI provided marginal sensitivity (limits of detection of about 0.1 microg/l) and selectivity was sometimes less in case of surface water samples. Both the on-line LVI-LC-LC-MS method and the LC-LC-UV method using off-line SPE were validated by analysing a series of real-life reference samples. These samples were part of an inter-laboratory test and contained residues of herbicides ranging from 0.02 to 0.8 microg/l. Beside good correlation between the methods

  10. Alienation, Mass Society and Mass Culture.

    Science.gov (United States)

    Dam, Hari N.

    This monograph examines the nature of alienation in mass society and mass culture. Conceptually based on the "Gemeinschaft-Gesellschaft" paradigm of sociologist Ferdinand Tonnies, discussion traces the concept of alienation as it appears in the philosophies of Hegel, Marx, Kierkegaard, Sartre, and others. Dwight Macdonald's "A Theory of Mass…

  11. Ultra-trace determination of Strontium-90 in environmental soil samples from Qatar by collision/reaction cell-inductively coupled plasma mass spectrometry (CRC-ICP-MS/MS)

    Energy Technology Data Exchange (ETDEWEB)

    Al-Meer, S. H.; Amr, M. A. [Central Laboratories Unit, Qatar University, Doha (Qatar); Helal, A.I. [Atomic Energy Authority, Cairo (Egypt); Al-Kinani, A.T. [Minstery of Environment, Doha (Qatar)

    2013-07-01

    Because of the very low level of {sup 90}Sr in the environmental soil samples and its determination by beta counting may take several weeks, we developed a procedure for ultra-trace determination of {sup 90}Sr using collision reaction cell-inductively coupled plasma tandem mass spectrometry (CRC-ICP-MS/MS, Agilent 8800). Soil samples were dried at 105 deg. C and then heated in a furnace at 550 deg. C to remove any organics present. 500 g of each soil samples were aliquoted into 2000 ml glass beakers. Each Soils samples were soaked in 2 ppm Sr solution carrier to allow determination of chemical yield. The solid to liquid ratio was 1:1. Finally the soil samples were dried at 105 deg. C. Five hundred milliliters concentrated nitric acid and 250 ml hydrochloric acid volumes were added on 500 g soil samples. The samples were digested on hot plate at 80 deg. C to prevent spraying with continuous manual mixing. The leachate solution was separated. The solids were rinsed with 500 ml deionized water, warmed on a hot plate and the leachate plus previous leachate were filtered and the total volume was reduced to 500 ml by evaporation. Final leachate volume was transferred to a centrifuge tubes. The centrifuge tubes were centrifuged at 3,500 rpm for 10 min. The leachate was transferred to a 1 L beaker and heated on a hot plate to evaporate the leachate to dryness. The reside was re-dissolved in 100 ml of 2% HNO{sub 3} and reduced by evaporation to 10 mL. The solution was measured directly by CRC-ICP-MS/MS by setting the first quadruple analyzer to m/z 90 and introducing oxygen gas into the reaction cell for elimination isobar interference from zirconium-90. The method was validated by measurements of standard reference materials and applied on environmental soil samples. The overall time requirement for the measurement of strontium-90 by CRC-ICP-MS/MS is 2 days, significantly shorter than any radioanalytical protocol currently available. (authors)

  12. Interactive Stable Ray Tracing

    DEFF Research Database (Denmark)

    Dal Corso, Alessandro; Salvi, Marco; Kolb, Craig

    2017-01-01

    Interactive ray tracing applications running on commodity hardware can suffer from objectionable temporal artifacts due to a low sample count. We introduce stable ray tracing, a technique that improves temporal stability without the over-blurring and ghosting artifacts typical of temporal post-pr...

  13. Nuclear traces in glass

    International Nuclear Information System (INIS)

    Segovia A, M. de N.

    1978-01-01

    The charged particles produce, in dielectric materials, physical and chemical effects which make evident the damaged zone along the trajectory of the particle. This damaged zone is known as the latent trace. The latent traces can be enlarged by an etching of the detector material. This treatment attacks preferently the zones of the material where the charged particles have penetrated, producing concavities which can be observed through a low magnification optical microscope. These concavities are known as developed traces. In this work we describe the glass characteristics as a detector of the fission fragments traces. In the first chapter we present a summary of the existing basic theories to explain the formation of traces in solids. In the second chapter we describe the etching method used for the traces development. In the following chapters we determine some chatacteristics of the traces formed on the glass, such as: the development optimum time; the diameter variation of the traces and their density according to the temperature variation of the detector; the glass response to a radiation more penetrating than that of the fission fragments; the distribution of the developed traces and the existing relation between this ditribution and the fission fragments of 252 Cf energies. The method which has been used is simple and cheap and can be utilized in laboratories whose resources are limited. The commercial glass which has been employed allows the registration of the fission fragments and subsequently the realization of experiments which involve the counting of the traces as well as the identification of particles. (author)

  14. Computer ray tracing speeds.

    Science.gov (United States)

    Robb, P; Pawlowski, B

    1990-05-01

    The results of measuring the ray trace speed and compilation speed of thirty-nine computers in fifty-seven configurations, ranging from personal computers to super computers, are described. A correlation of ray trace speed has been made with the LINPACK benchmark which allows the ray trace speed to be estimated using LINPACK performance data. The results indicate that the latest generation of workstations, using CPUs based on RISC (Reduced Instruction Set Computer) technology, are as fast or faster than mainframe computers in compute-bound situations.

  15. Tracing Planets in Circumstellar Discs

    Directory of Open Access Journals (Sweden)

    Uribe Ana L.

    2013-04-01

    Full Text Available Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (submm wavelength range for the Atacama Large (SubMillimeter Array (ALMA. On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (submm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20°. The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses, nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67·10-7 M⊙ and 4.10·10-2 M⊙, six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4...2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplane tary discs (0.1 M⊙...0.001 M⊙ the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67·10-6 M⊙ and trace gaps in discs with 2.67·10-4 M⊙ with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of

  16. Traces of Drosophila Memory

    Science.gov (United States)

    Davis, Ronald L.

    2012-01-01

    Summary Studies using functional cellullar imaging of living flies have identified six memory traces that form in the olfactory nervous system after conditioning with odors. These traces occur in distinct nodes of the olfactory nervous system, form and disappear across different windows of time, and are detected in the imaged neurons as increased calcium influx or synaptic release in response to the conditioned odor. Three traces form at, or near acquisition and co-exist with short-term behavioral memory. One trace forms with a delay after learning and co-exists with intermediate-term behavioral memory. Two traces form many hours after acquisition and co-exist with long-term behavioral memory. The transient memory traces may support behavior across the time-windows of their existence. The experimental approaches for dissecting memory formation in the fly, ranging from the molecular to the systems, make it an ideal system for dissecting the logic by which the nervous system organizes and stores different temporal forms of memory. PMID:21482352

  17. TraceContract

    Science.gov (United States)

    Kavelund, Klaus; Barringer, Howard

    2012-01-01

    TraceContract is an API (Application Programming Interface) for trace analysis. A trace is a sequence of events, and can, for example, be generated by a running program, instrumented appropriately to generate events. An event can be any data object. An example of a trace is a log file containing events that a programmer has found important to record during a program execution. Trace - Contract takes as input such a trace together with a specification formulated using the API and reports on any violations of the specification, potentially calling code (reactions) to be executed when violations are detected. The software is developed as an internal DSL (Domain Specific Language) in the Scala programming language. Scala is a relatively new programming language that is specifically convenient for defining such internal DSLs due to a number of language characteristics. This includes Scala s elegant combination of object-oriented and functional programming, a succinct notation, and an advanced type system. The DSL offers a combination of data-parameterized state machines and temporal logic, which is novel. As an extension of Scala, it is a very expressive and convenient log file analysis framework.

  18. Particle tracing code for multispecies gas

    International Nuclear Information System (INIS)

    Eaton, R.R.; Fox, R.L.; Vandevender, W.H.

    1979-06-01

    Details are presented for the development of a computer code designed to calculate the flow of a multispecies gas mixture using particle tracing techniques. The current technique eliminates the need for a full simulation by utilizing local time averaged velocity distribution functions to obtain the dynamic properties for probable collision partners. The development of this concept reduces statistical scatter experienced in conventional Monte Carlo simulations. The technique is applicable to flow problems involving gas mixtures with disparate masses and trace constituents in the Knudsen number, Kn, range from 1.0 to less than 0.01. The resulting code has previously been used to analyze several aerodynamic isotope enrichment devices

  19. A dynamic gravimetric standard for trace water.

    Science.gov (United States)

    Brewer, P J; Goody, B A; Woods, P T; Milton, M J T

    2011-10-01

    A system for generating traceable reference standards of water vapor at trace levels between 5 and 2000 nmol/mol has been developed. It can provide different amount fractions of trace water vapor by using continuous accurate measurements of mass loss from a permeation device coupled with a dilution system based on an array of critical flow orifices. An estimated relative expanded uncertainty of ±2% has been achieved for most amount fractions generated. The system has been used in an international comparison and demonstrates excellent comparability with National Metrology Institutes maintaining standards of water vapor in this range using other methods.

  20. Intraoral gothic arch tracing.

    Science.gov (United States)

    Rubel, Barry; Hill, Edward E

    2011-01-01

    In order to create optimum esthetics, function and phonetics in complete denture fabrication, it is necessary to record accurate maxillo-mandibular determinants of occlusion. This requires clinical skill to establish an accurate, verifiable and reproducible vertical dimension of occlusion (VDO) and centric relation (CR). Correct vertical relation depends upon a consideration of several factors, including muscle tone, inter-dental arch space and parallelism of the ridges. Any errors made while taking maxillo-mandibular jaw relation records will result in dentures that are uncomfortable and, possibly, unwearable. The application of a tracing mechanism such as the Gothic arch tracer (a central bearing device) is a demonstrable method of determining centric relation. Intraoral Gothic arch tracers provide the advantage of capturing VDO and CR in an easy-to-use technique for practitioners. Intraoral tracing (Gothic arch tracing) is a preferred method of obtaining consistent positions of the mandible in motion (retrusive, protrusive and lateral) at a comfortable VDO.

  1. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  2. Atom trap trace analysis

    International Nuclear Information System (INIS)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O'Connor, T. P.; Young, L.

    2000-01-01

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual 85 Kr and 81 Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10 -11 and 10 -13 , respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications

  3. Oscilloscope trace photograph digitizing system (TRACE)

    International Nuclear Information System (INIS)

    Richards, M.; Dabbs, R.D.

    1977-10-01

    The digitizing system allows digitization of photographs or sketches of waveforms and then the computer is used to reduce and analyze the data. The software allows for alignment, calibration, removal of baselines, removal of unwanted points and addition of new points which makes for a fairly versatile system as far as data reduction and manipulation are concerned. System considerations are introduced first to orient the potential user to the process of digitizing information. The start up and actual commands for TRACE are discussed. Detailed descriptions of each subroutine and program section are also provided. Three general examples of typical photographs are included. A partial listing of FAWTEK is made available. Once suitable arrays that contain the data are arranged, ''GO FA'' (active FAWTEK) and many mathematical operations to further analyze the data may be performed

  4. Queer Tracings of Genre

    DEFF Research Database (Denmark)

    Balle, Søren Hattesen

    as (re)tracings of genres that appear somehow residual or defunct in a post-modernist poetic context. On the other, they are made to "encode new [and queer, shb] meanings" (Anne Ferry) inasmuch as Ashbery, for instance, doubles and literalizes Dante's false etymology of the word ‘eclogue' (aig- and logos...

  5. The Trace of Superusers

    DEFF Research Database (Denmark)

    Samson, Kristine; Abasolo, José

    2013-01-01

    The city and its public spaces can be seen as a fragmented whole carrying meanings and traces of culture, use and politics with it. Whereas architects impose new stories and meanings on the urban fabric, the city itself is layered and assembled, a collective of social flows and routines a result ...

  6. Third order trace formula

    Indian Academy of Sciences (India)

    N. Centre for Advanced Scientific Research, Bangalore 560 064, India. 2Indian Institute of ... for rational functions φ with poles off R. In [5,16], Koplienko's trace formula was derived ... be a sequence of complex numbers such that ..... Again if we set the sum of the second and fourth term inside the integral in (2.3) to be. I2 ≡.

  7. Implementation of suitable flow injection/sequential-sample separation/preconcentration schemes for determination of trace metal concentrations using detection by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Wang, Jianhua

    2002-01-01

    Various preconditioning procedures encomprising appropriate separation/preconcentration schemes in order to obtain optimal sensitivity and selectivity characteristics when using electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICPMS...

  8. Standard Model Effective Potential from Trace Anomalies

    Directory of Open Access Journals (Sweden)

    Renata Jora

    2018-01-01

    Full Text Available By analogy with the low energy QCD effective linear sigma model, we construct a standard model effective potential based entirely on the requirement that the tree level and quantum level trace anomalies must be satisfied. We discuss a particular realization of this potential in connection with the Higgs boson mass and Higgs boson effective couplings to two photons and two gluons. We find that this kind of potential may describe well the known phenomenology of the Higgs boson.

  9. Mass: Fortran program for calculating mass-absorption coefficients

    International Nuclear Information System (INIS)

    Nielsen, Aa.; Svane Petersen, T.

    1980-01-01

    Determinations of mass-absorption coefficients in the x-ray analysis of trace elements are an important and time consuming part of the arithmetic calculation. In the course of time different metods have been used. The program MASS calculates the mass-absorption coefficients from a given major element analysis at the x-ray wavelengths normally used in trace element determinations and lists the chemical analysis and the mass-absorption coefficients. The program is coded in FORTRAN IV, and is operational on the IBM 370/165 computer, on the UNIVAC 1110 and on PDP 11/05. (author)

  10. Limit of detection in the presence of instrumental and non-instrumental errors: study of the possible sources of error and application to the analysis of 41 elements at trace levels by inductively coupled plasma-mass spectrometry technique

    International Nuclear Information System (INIS)

    Badocco, Denis; Lavagnini, Irma; Mondin, Andrea; Tapparo, Andrea; Pastore, Paolo

    2015-01-01

    In this paper the detection limit was estimated when signals were affected by two error contributions, namely instrumental errors and operational-non-instrumental errors. The detection limit was theoretically obtained following the hypothesis testing schema implemented with the calibration curve methodology. The experimental calibration design was based on J standards measured I times with non-instrumental errors affecting each standard systematically but randomly among the J levels. A two-component variance regression was performed to determine the calibration curve and to define the detection limit in these conditions. The detection limit values obtained from the calibration at trace levels of 41 elements by ICP-MS resulted larger than those obtainable from a one component variance regression. The role of the reagent impurities on the instrumental errors was ascertained and taken into account. Environmental pollution was studied as source of non-instrumental errors. The environmental pollution role was evaluated by Principal Component Analysis technique (PCA) applied to a series of nine calibrations performed in fourteen months. The influence of the seasonality of the environmental pollution on the detection limit was evidenced for many elements usually present in the urban air particulate. The obtained results clearly indicated the need of using the two-component variance regression approach for the calibration of all the elements usually present in the environment at significant concentration levels. - Highlights: • Limit of detection was obtained considering a two variance component regression. • Calibration data may be affected by instrumental and operational conditions errors. • Calibration model was applied to determine 41 elements at trace level by ICP-MS. • Non instrumental errors were evidenced by PCA analysis

  11. Trace elements distribution in environmental compartments

    International Nuclear Information System (INIS)

    Queiroz, Juliana C. de; Peres, Sueli da Silva; Godoy, Maria Luiza D.P.

    2017-01-01

    Trace elements term defines the presence of low concentrations metals at environment. Some of them are considered biologically essential, as Co, Cu and Mn. Others can cause detriment to environment and human health, as Pb, Cd, Hg, As, Ti and U. A large number of them have radioactive isotopes, implying the evaluation of risks for human health should be done considering the precepts of environmental radiological protection. The ecosystem pollution with trace elements generates changes at the geochemistry cycle of these elements and in environmental quality. Soils have single characteristics when compared with another components of biosphere (air, water and biota), cause they introduce themselves not only as a drain towards contaminants, but also as natural buffer that control the transport of chemical elements and other substances for atmosphere, hydrosphere and biota. The main purpose of environmental monitoring program is to evaluate the levels of contaminants in the various compartments of the environment: natural or anthropogenic, and to assess the contribution of a potential contaminant source on the environment. Elemental Composition for the collected samples was determined by inductively coupled plasma mass spectroscopy. The main objective of this work was to evaluate the map baseline of concentration of interest trace elements in environmental samples of water, sediment and soil from Environmental Monitoring Program of Instituto de Radioprotecao e Dosimetria (IRD). The samples were analyzed using an inductively coupled plasma mass spectrometer (ICP-MS) at IRD. >From the knowledge of trace elements concentrations, could be evaluated the environmental quality parameters at the studied ecosystems. The data allowed evaluating some relevant aspects of the study of trace elements in soil and aquatic systems, with emphasis at the distribution, concentration and identification of main anthropic sources of contamination at environment. (author)

  12. Trace elements distribution in environmental compartments

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Juliana C. de; Peres, Sueli da Silva; Godoy, Maria Luiza D.P., E-mail: suelip@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-11-01

    Trace elements term defines the presence of low concentrations metals at environment. Some of them are considered biologically essential, as Co, Cu and Mn. Others can cause detriment to environment and human health, as Pb, Cd, Hg, As, Ti and U. A large number of them have radioactive isotopes, implying the evaluation of risks for human health should be done considering the precepts of environmental radiological protection. The ecosystem pollution with trace elements generates changes at the geochemistry cycle of these elements and in environmental quality. Soils have single characteristics when compared with another components of biosphere (air, water and biota), cause they introduce themselves not only as a drain towards contaminants, but also as natural buffer that control the transport of chemical elements and other substances for atmosphere, hydrosphere and biota. The main purpose of environmental monitoring program is to evaluate the levels of contaminants in the various compartments of the environment: natural or anthropogenic, and to assess the contribution of a potential contaminant source on the environment. Elemental Composition for the collected samples was determined by inductively coupled plasma mass spectroscopy. The main objective of this work was to evaluate the map baseline of concentration of interest trace elements in environmental samples of water, sediment and soil from Environmental Monitoring Program of Instituto de Radioprotecao e Dosimetria (IRD). The samples were analyzed using an inductively coupled plasma mass spectrometer (ICP-MS) at IRD. >From the knowledge of trace elements concentrations, could be evaluated the environmental quality parameters at the studied ecosystems. The data allowed evaluating some relevant aspects of the study of trace elements in soil and aquatic systems, with emphasis at the distribution, concentration and identification of main anthropic sources of contamination at environment. (author)

  13. Software trace cache

    OpenAIRE

    Ramírez Bellido, Alejandro; Larriba Pey, Josep; Valero Cortés, Mateo

    2005-01-01

    We explore the use of compiler optimizations, which optimize the layout of instructions in memory. The target is to enable the code to make better use of the underlying hardware resources regardless of the specific details of the processor/architecture in order to increase fetch performance. The Software Trace Cache (STC) is a code layout algorithm with a broader target than previous layout optimizations. We target not only an improvement in the instruction cache hit rate, but also an increas...

  14. On Trace Zero Matrices

    Indian Academy of Sciences (India)

    In this note, we shall try to present an elemen- tary proof of a couple of closely related results which have both proved quite useful, and al~ indicate possible generalisations. The results we have in mind are the following facts: (a) A complex n x n matrix A has trace 0 if and only if it is expressible in the form A = PQ - Q P.

  15. Preconcentration of trace elements

    International Nuclear Information System (INIS)

    Zolotov, Yu. A.; Kuz'min, N.M.

    1990-01-01

    This monograph deals with the theory and practical applications of trace metals preconcentration. It gives general characteristics of the process and describes in detail the methods of preconcentration: solvent extraction, sorption, co-precipitation, volatilization, and others. Special attention is given to preconcentration in combination with subsequent determination methods. The use of preconcentration in analysis of environmental and biological samples, mineral raw materials, high purity substances, and various industrial materials is also considered

  16. Anisotropic ray trace

    Science.gov (United States)

    Lam, Wai Sze Tiffany

    Optical components made of anisotropic materials, such as crystal polarizers and crystal waveplates, are widely used in many complex optical system, such as display systems, microlithography, biomedical imaging and many other optical systems, and induce more complex aberrations than optical components made of isotropic materials. The goal of this dissertation is to accurately simulate the performance of optical systems with anisotropic materials using polarization ray trace. This work extends the polarization ray tracing calculus to incorporate ray tracing through anisotropic materials, including uniaxial, biaxial and optically active materials. The 3D polarization ray tracing calculus is an invaluable tool for analyzing polarization properties of an optical system. The 3x3 polarization ray tracing P matrix developed for anisotropic ray trace assists tracking the 3D polarization transformations along a ray path with series of surfaces in an optical system. To better represent the anisotropic light-matter interactions, the definition of the P matrix is generalized to incorporate not only the polarization change at a refraction/reflection interface, but also the induced optical phase accumulation as light propagates through the anisotropic medium. This enables realistic modeling of crystalline polarization elements, such as crystal waveplates and crystal polarizers. The wavefront and polarization aberrations of these anisotropic components are more complex than those of isotropic optical components and can be evaluated from the resultant P matrix for each eigen-wavefront as well as for the overall image. One incident ray refracting or reflecting into an anisotropic medium produces two eigenpolarizations or eigenmodes propagating in different directions. The associated ray parameters of these modes necessary for the anisotropic ray trace are described in Chapter 2. The algorithms to calculate the P matrix from these ray parameters are described in Chapter 3 for

  17. Tracers and tracing methods

    International Nuclear Information System (INIS)

    Leclerc, J.P.

    2001-01-01

    The first international congress on 'Tracers and tracing methods' took place in Nancy in May 2001. The objective of this second congress was to present the current status and trends on tracing methods and their applications. It has given the opportunity to people from different fields to exchange scientific information and knowledge about tracer methodologies and applications. The target participants were the researchers, engineers and technologists of various industrial and research sectors: chemical engineering, environment, food engineering, bio-engineering, geology, hydrology, civil engineering, iron and steel production... Two sessions have been planned to cover both fundamental and industrial aspects: 1)fundamental development (tomography, tracer camera visualization and particles tracking; validation of computational fluid dynamics simulations by tracer experiments and numerical residence time distribution; new tracers and detectors or improvement and development of existing tracing methods; data treatments and modeling; reactive tracer experiments and interpretation) 2)industrial applications (geology, hydrogeology and oil field applications; civil engineering, mineral engineering and metallurgy applications; chemical engineering; environment; food engineering and bio-engineering). The program included 5 plenary lectures, 23 oral communications and around 50 posters. Only 9 presentations are interested for the INIS database

  18. Mass spectrometry in clinical chemistry

    International Nuclear Information System (INIS)

    Pettersen, J.E.

    1977-01-01

    A brief description is given of the functional elements of a mass spectrometer and of some currently employed mass spectrometric techniques, such as combined gas chromatography-mass spectrometry, mass chromatography, and selected ion monitoring. Various areas of application of mass spectrometry in clinical chemistry are discussed, such as inborn errors of metabolism and other metabolic disorders, intoxications, quantitative determinations of drugs, hormones, gases, and trace elements, and the use of isotope dilution mass spectrometry as a definitive method for the establishment of true values for concentrations of various compounds in reference sera. It is concluded that mass spectrometry is of great value in clinical chemistry. (Auth.)

  19. Calorimetric low-temperature detectors for low-energy (E≤1 MeV/amu) heavy ions and their first application in the accelerator mass spectroscopy for trace analysis of 236U

    International Nuclear Information System (INIS)

    Kraft-Bermuth, S.

    2004-01-01

    In the thesis presented here, calorimetric low temperature detectors were for the first time applied in accelerator mass spectrometry (AMS) to determine the isotope ratio of 236 U to 238 U in several samples of natural uranium. The detectors consist of a superconducting aluminium film deposited onto a sapphire absorber which is used as thermistor. An energetic heavy ion deposits its kinetic energy as heat in the absorber. The temperature rise is detected by the resistance change of the superconductor. The AMS experiments were performed at the tandem accelerator VERA of the ''Institut fuer Isotopenforschung und Kernphysik'' of the University of Vienna. In an energy range of 10-60 MeV, a relative energy resolution of ΔE/E=7.10 -3 could be achieved, one order of magnitude better than with conventional ionization detectors. Improving thermal and electronic noise yielded in a second experiment for uranium ions with E=17 MeV a relative energy resolution of ΔE/E=4.6.10 -3 . The energy response of the detectors was linear over the whole energy range and independent of the ion mass. Down to a level of 0.1%, no pulse height defect was observed. With the energy resolution obtained it is possible to determine the isotope ratio of 236 U/ 238 U for several samples of natural uranium. With the resolution achieved it is possible furthermore to apply the detectors in several test experiments for direct mass identification of heavy ions using a combined energy/time of flight measurement. In these first tests, a mass resolution of ΔM/M=(8.5-11.0).10 -3 was achieved. In a first test to apply the detectors for detection of so called ''super heavy elements (Z>=112)'', the large dynamic range allowed to identify the reaction products and their alpha decays simultaneously and time dependent. (orig.)

  20. Simultaneous determination of niacin and pyridoxine at trace levels by using diode array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Sel, Sabriye; Öztürk Er, Elif; Bakırdere, Sezgin

    2017-12-01

    A highly sensitive and simple diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method was developed for the simultaneous determination of niacin and pyridoxine in pharmaceutical drugs, tap water, and wastewater samples. To determine the in vivo behavior of niacin and pyridoxine, analytes were subjected to simulated gastric conditions. The calibration plots of the diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method showed good linearity over a wide concentration range with close to 1.0 correlation coefficients for both analytes. The limit of detection/limit of quantitation values for liquid chromatography quadrupole time-of-flight tandem mass spectrometry analysis were 1.98/6.59 and 1.3/4.4 μg/L for niacin and pyridoxine, respectively, while limit of detection/limit of quantitation values for niacin and pyridoxine in high-performance liquid chromatography analysis were 3.7/12.3 and 5.7/18.9 μg/L, respectively. Recovery studies were also performed to show the applicability of the developed methods, and percentage recovery values were found to be 90-105% in tap water and 94-97% in wastewater for both analytes. The method was also successfully applied for the qualitative and quantitative determination of niacin and pyridoxine in drug samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Sequential injection-bead injection-lab-on-valve schemes for on-line solid phase extraction and preconcentration of ultra-trace levels of heavy metals with determination by electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Wang Jianhua; Hansen, Elo Harald; Miro, Manuel

    2003-01-01

    This communication presents an overview of the state-of-the-art of the exploitation of sequential injection (SI)-bead injection (BI)-lab-on-valve (LOV) schemes for automatic on-line sample pre-treatments interfaced with ETAAS and ICPMS detection as conducted in the authors' group. The discussions are focused on the applications of SI-BI-LOV protocols for on-line microcolumn based solid phase extraction of ultra-trace levels of heavy metals, employing the so-called renewable surface separation and preconcentration manipulatory scheme. Two types of sorbents have been employed as packing material, that is, the hydrophilic SP Sephadex C-25 cation exchange and iminodiacetate based Muromac A-1 chelating resins, and the hydrophobic poly(tetrafluoroethylene) (PTFE) and poly(styrene-divinylbenzene) copolymer alkylated with octadecyl groups (C 18 -PS/DVB). Using ETAAS as detection device, the easy-to-handle hydrophilic renewable reactors hold the features of improved R.S.D.s and LODs as compared to those operated in the conventional, permanent mode, in addition to the elimination of flow resistance. The hydrophobic columns fall into two categories, that is, the renewable one packed with C 18 -PS/DVB beads entails analogous R.S.D.s and LODs with respect to the conventional approach, while those with PTFE beads result in slightly inferior R.S.D.s and LODs by similar comparison, yet offering a wider dynamic range than when using an external permanent column. Moreover, the hydrophilic materials result in much higher enrichment of the analyte than the hydrophobic ones, although PTFE is the packing material that exhibits the best retention efficiency

  2. Linac particle tracing simulations

    International Nuclear Information System (INIS)

    Lysenko, W.P.

    1979-01-01

    A particle tracing code was developed to study space--charge effects in proton or heavy-ion linear accelerators. The purpose is to study space--charge phenomena as directly as possible without the complications of many accelerator details. Thus, the accelerator is represented simply by harmonic oscillator or impulse restoring forces. Variable parameters as well as mismatched phase--space distributions were studied. This study represents the initial search for those features of the accelerator or of the phase--space distribution that lead to emittance growth

  3. Trace conditioning in insects-keep the trace!

    Science.gov (United States)

    Dylla, Kristina V; Galili, Dana S; Szyszka, Paul; Lüdke, Alja

    2013-01-01

    Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS) and an unconditioned stimulus (US) following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination-a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase (Rut-AC), which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

  4. Trace conditioning in insects – Keep the trace!

    Directory of Open Access Journals (Sweden)

    Kristina V Dylla

    2013-08-01

    Full Text Available Trace conditioning is a form of associative learning that can be induced by presenting a conditioned stimulus (CS and an unconditioned stimulus (US following each other, but separated by a temporal gap. This gap distinguishes trace conditioning from classical delay conditioning, where the CS and US overlap. To bridge the temporal gap between both stimuli and to form an association between CS and US in trace conditioning, the brain must keep a neural representation of the CS after its termination – a stimulus trace. Behavioral and physiological studies on trace and delay conditioning revealed similarities between the two forms of learning, like similar memory decay and similar odor identity perception in invertebrates. On the other hand differences were reported also, like the requirement of distinct brain structures in vertebrates or disparities in molecular mechanisms in both vertebrates and invertebrates. For example, in commonly used vertebrate conditioning paradigms the hippocampus is necessary for trace but not for delay conditioning, and Drosophila delay conditioning requires the Rutabaga adenylyl cyclase, which is dispensable in trace conditioning. It is still unknown how the brain encodes CS traces and how they are associated with a US in trace conditioning. Insects serve as powerful models to address the mechanisms underlying trace conditioning, due to their simple brain anatomy, behavioral accessibility and established methods of genetic interference. In this review we summarize the recent progress in insect trace conditioning on the behavioral and physiological level and emphasize similarities and differences compared to delay conditioning. Moreover, we examine proposed molecular and computational models and reassess different experimental approaches used for trace conditioning.

  5. Piezoelectric trace vapor calibrator

    International Nuclear Information System (INIS)

    Verkouteren, R. Michael; Gillen, Greg; Taylor, David W.

    2006-01-01

    The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10 deg. C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver--on demand--continuous vapor concentrations across more than six orders of magnitude (nominally 290 fg/l to 1.05 μg/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process

  6. Analytical capabilities of high performance liquid chromatography - Atmospheric pressure photoionization - Orbitrap mass spectrometry (HPLC-APPI-Orbitrap-MS) for the trace determination of novel and emerging flame retardants in fish.

    Science.gov (United States)

    Zacs, D; Bartkevics, V

    2015-10-22

    A new analytical method was established and validated for the analysis of 27 brominated flame retardants (BFRs), including so called "emerging" and "novel" BFRs (EBFRs and NBFRs) in fish samples. High performance liquid chromatography (HPLC) coupled to Orbitrap mass spectrometry (Orbitrap-MS) employing atmospheric pressure photoionization (APPI) interface operated in negative mode was used for the identification/quantitation of contaminants. HPLC-Orbitrap-MS analysis provided a fast separation of selected analytes within 14 min, thus demonstrating a high throughput processing of samples. The developed methodology was tested by intralaboratory validation in terms of recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ), and where possible, trueness was verified by analysis of certified reference materials (CRMs). Recoveries of analytes were between 80 and 119%, while the repeatability in terms of relative standard deviations (RSDs) was in the range from 1.2 to 15.5%. The measured values for both analyzed CRMs agreed with the provided consensus values, revealing the recovery of reference concentrations in 72-119% range. The elaborated method met the sensitivity criterion according to Commission Recommendation 2014/118/EU on monitoring of BFRs in food products for majority of the compounds. The concentrations of polybrominated diphenyl ethers (PBDEs) in real samples determined by HPLC-APPI-Orbitrap-MS method and validated gas chromatography-high-resolution mass spectrometry (GC-HRMS) method were found to be in a good agreement. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Traces generating what was there

    CERN Document Server

    2017-01-01

    Traces keep time contained and make visible what was there. Going back to the art of trace-reading, they continue to be a fundamental resource for scientific knowledge production. The contributions study, from the biology laboratory to the large colliders of particle physics, techniques involved in the production of material traces. Following their changes over two centuries, this collection shows the continuities they have in the digital age.

  8. Trace Mineral Losses in Sweat

    National Research Council Canada - National Science Library

    Chinevere, Troy D; McClung, James P; Cheuvront, Samuel N

    2007-01-01

    Copper, iron and zinc are nutritionally essential trace minerals that confer vital biological roles including the maintenance of cell structure and integrity, regulation of metabolism, immune function...

  9. Trace analysis of semiconductor materials

    CERN Document Server

    Cali, J Paul; Gordon, L

    1964-01-01

    Trace Analysis of Semiconductor Materials is a guidebook concerned with procedures of ultra-trace analysis. This book discusses six distinct techniques of trace analysis. These techniques are the most common and can be applied to various problems compared to other methods. Each of the four chapters basically includes an introduction to the principles and general statements. The theoretical basis for the technique involved is then briefly discussed. Practical applications of the techniques and the different instrumentations are explained. Then, the applications to trace analysis as pertaining

  10. Assessment of TRACE code against CHF experiments

    International Nuclear Information System (INIS)

    Audrius Jasiulevicius; Rafael Macian-Juan; Paul Coddington

    2005-01-01

    Full text of publication follows: This paper reports on the validation of the USNRC 'consolidate' code TRACE with data obtained during Critical Heat Flux (CHF) experiments in single channels and round and annular tubes. CHF is one of the key reactor safety parameters, because it determines the conditions for the onset of transition boiling in the core rod bundles, leading to the low heat transfer rates characteristics of the post-CHF heat transfer regime. In the context of the participation of PSI in the the International Programme for uncertainty analysis BEMUSE, we have carried out extensive work for the validation of some important TRACE models. The present work is aimed at assessing the range of validity for the CHF correlations and post-CHF heat transfer models currently included in TRACE. The heat transfer experiments selected for the assessment were performed at the Royal Institute of Technology (RIT) in Stockholm, Sweden and at the Atomic Energy Establishment in Winfrith, UK. The experimental investigations of the CHF and post-CHF heat transfer at RIT for flow of water in vertical tubes and annulus were performed at pressures ranging from 1 to 20 MPa and coolant mass fluxes from 500 to 3000 kg/m 2 s. The liquid was subcooled by 10 deg. C and 40 deg. C at the inlet of the test section. The experiments were performed on two different types of test sections. Experiments with uniformly heated single 7.0 m long tubes were carried out with three different inner tube diameters of 10, 14.9 and 24.7 mm. A series of experiments with non-uniform axial power distribution were also conducted in order to study the effect of the axial heat flux distribution on the CHF conditions in both 7.0 m long single tubes and 3.65 long annulus. Several different axial power profiles were employed with bottom, middle and top power peaks as well as the double-humped axial power profiles. In total more than 100 experiments with uniform axial heat flux distribution and several hundreds

  11. Trace anomaly and counterterms in designer gravity

    Energy Technology Data Exchange (ETDEWEB)

    Anabalón, Andrés [Departamento de Ciencias, Facultad de Artes Liberalesand Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Av. Padre Hurtado 750, Viña del Mar (Chile); Astefanesei, Dumitru [Instituto de Física, Pontificia Universidad Católica de Valparaíso,Casilla 4059, Valparaíso (Chile); Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut,14476 Golm (Germany); Choque, David [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut,14476 Golm (Germany); Universidad Técnica Federico Santa María,Av. España 1680, Valparaíso (Chile); Martínez, Cristián [Centro de Estudios Científicos (CECs),Av. Arturo Prat 514, Valdivia (Chile)

    2016-03-17

    We construct concrete counterterms of the Balasubramanian-Kraus type for Einstein-scalar theories with designer gravity boundary conditions in AdS{sub 4}, so that the total action is finite on-shell and satisfy a well defined variational principle. We focus on scalar fields with the conformal mass m{sup 2}=−2l{sup −2} and show that the holographic mass matches the Hamiltonian mass for any boundary conditions. We compute the trace anomaly of the dual field theory in the generic case, as well as when there exist logarithmic branches of non-linear origin. As expected, the anomaly vanishes for the boundary conditions that are AdS invariant. When the anomaly does not vanish, the dual stress tensor describes a thermal gas with an equation of state related to the boundary conditions of the scalar field. In the case of a vanishing anomaly, we recover the dual theory of a massless thermal gas. As an application of the formalism, we consider a general family of exact hairy black hole solutions that, for some particular values of the parameters in the moduli potential, contains solutions of four-dimensional gauged N=8 supergravity and its ω-deformation. Using the AdS/CFT duality dictionary, they correspond to triple trace deformations of the dual field theory.

  12. Trace anomaly and counterterms in designer gravity

    International Nuclear Information System (INIS)

    Anabalón, Andrés; Astefanesei, Dumitru; Choque, David; Martínez, Cristián

    2016-01-01

    We construct concrete counterterms of the Balasubramanian-Kraus type for Einstein-scalar theories with designer gravity boundary conditions in AdS_4, so that the total action is finite on-shell and satisfy a well defined variational principle. We focus on scalar fields with the conformal mass m"2=−2l"−"2 and show that the holographic mass matches the Hamiltonian mass for any boundary conditions. We compute the trace anomaly of the dual field theory in the generic case, as well as when there exist logarithmic branches of non-linear origin. As expected, the anomaly vanishes for the boundary conditions that are AdS invariant. When the anomaly does not vanish, the dual stress tensor describes a thermal gas with an equation of state related to the boundary conditions of the scalar field. In the case of a vanishing anomaly, we recover the dual theory of a massless thermal gas. As an application of the formalism, we consider a general family of exact hairy black hole solutions that, for some particular values of the parameters in the moduli potential, contains solutions of four-dimensional gauged N=8 supergravity and its ω-deformation. Using the AdS/CFT duality dictionary, they correspond to triple trace deformations of the dual field theory.

  13. Trace impurity analyzer

    International Nuclear Information System (INIS)

    Schneider, W.J.; Edwards, D. Jr.

    1979-01-01

    The desirability for long-term reliability of large scale helium refrigerator systems used on superconducting accelerator magnets has necessitated detection of impurities to levels of a few ppM. An analyzer that measures trace impurity levels of condensable contaminants in concentrations of less than a ppM in 15 atm of He is described. The instrument makes use of the desorption temperature at an indicated pressure of the various impurities to determine the type of contaminant. The pressure rise at that temperature yields a measure of the contaminant level of the impurity. A LN 2 cryogenic charcoal trap is also employed to measure air impurities (nitrogen and oxygen) to obtain the full range of contaminant possibilities. The results of this detector which will be in use on the research and development helium refrigerator of the ISABELLE First-Cell is described

  14. Determination of trace elements in high pure rare earth oxide by double focusing inductively coupled plasma mass spectrometry (HR ICP-MS) and high performance liquid chromatography (HPLC) techniques

    International Nuclear Information System (INIS)

    Pedreira Filho, Walter dos Reis

    2000-01-01

    Rare earth oxides are used in several technological fields whose applications can be observed in several areas of modern technology, among which are included: lasers, semiconductors semi, high purity materials and metallic alloys. The field of applications of the rare earth elements is quite wide. Several important industrial applications are ceramics, catalysts and metallurgical as well as research areas and high technology sectors. Such applications have been presenting an accentuated growth in the last years. Chemical characterization of rare earth oxides of high purity has been constituting one of the major challenges of analytical chemistry. Several analytical techniques were used for chemical characterization of high purity rare earth the oxides. Even so, those techniques present limitations when one needs to characterize materials of a high level of purity, as in the case of rare earth oxides. Some of those limitations are associated, for example, to spectral interference. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is a powerful analytical tool for quantitative analysis of metal impurities in high purity materials. The Instituto de Pesquisas Energeticas e Nucleares (IPEN) has an unit of production and purification of rare earth oxides, with above 99,9% level of purity. In this work, the rare earth impurities were characterized in samples (La 2 O 3 ; CeO 2 ; Pr 6 O 11 ; Nd 2 O 3 ; Sm 2 O 3 ; Gd 2 O 3 ; Y 2 O 3 ) produced at the IPEN and certified standard materials produced by Johnson Matthey Chemical (JMC). The technique of high performance liquid chromatography (HPLC) was used in the separation of the impurities. Quantification of metallic impurities was carried out as inductively coupled plasma mass spectrometer (HR-ICP MS). In this work it is presented a new analytical methodology in the chemical characterization of metallic impurities in rare earth oxides of high purity (> 99,9%) with and without separation of the matrix. Analyses of standard

  15. Isotope dilution inductively coupled plasma quadrupole mass spectrometry in connection with a chromatographic separation for ultra trace determinations of platinum group elements (Pt, Pd, Ru, Ir) in environmental samples.

    Science.gov (United States)

    Müller, M; Heumann, K G

    2000-09-01

    An isotope dilution inductively coupled plasma quadrupole mass spectrometric (ID-ICP-QMS) method was developed for the simultaneous determination of the platinum group elements Pt, Pd, Ru, and Ir in environmental samples. Spike solutions, enriched with the isotopes 194Pt, 108Pd, 99Ru, and 191Ir, were used for the isotope dilution step. Interfering elements were eliminated by chromatographic separation using an anion-exchange resin. Samples were dissolved with aqua regia in a high pressure asher. Additional dissolution of possible silicate portions by hydrofluoric acid was usually not necessary. Detection limits of 0.15 ng x g(-1), 0.075 ng x g(-1), and 0.015 ng x g(-1) were achieved for Pt, Pd, Ru, and Ir, respectively, using sample weights of only 0.2 g. The reliability of the ID-ICP-QMS method was demonstrated by analyzing a Canadian geological reference material and by participating in an interlaboratory study for the determination of platinum and palladium in a homogenized road dust sample. Surface soil, sampled at different distances from a highway, showed concentrations in the range of 0.1-87 ng x g(-1). An exponential decrease of the platinum and palladium concentration with increasing distance and a small anthropogenic contribution to the natural background concentration of ruthenium and iridium was found in these samples.

  16. Ultra-trace levels analysis of microcystins and nodularin in surface water by on-line solid-phase extraction with high-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Balest, Lydia; Murgolo, Sapia; Sciancalepore, Lucia; Montemurro, Patrizia; Abis, Pier Paolo; Pastore, Carlo; Mascolo, Giuseppe

    2016-06-01

    An on-line solid phase extraction coupled with high-performance liquid chromatography in tandem with mass spectrometry (on-line SPE/HPLC/MS-MS) method for the determination of five microcystins and nodularin in surface waters at submicrogram per liter concentrations has been optimized. Maximum recoveries were achieved by carefully optimizing the extraction sample volume, loading solvent, wash solvent, and pH of the sample. The developed method was also validated according to both UNI EN ISO IEC 17025 and UNICHIM guidelines. Specifically, ten analytical runs were performed at three different concentration levels using a reference mix solution containing the six analytes. The method was applied for monitoring the concentrations of microcystins and nodularin in real surface water during a sampling campaign of 9 months in which the ELISA method was used as standard official method. The results of the two methods were compared showing good agreement when the highest concentration values of MCs were found. Graphical abstract An on-line SPE/HPLC/MS-MS method for the determination of five microcystins and nodularin in surface waters at sub μg L(-1) was optimized and compared with ELISA assay method for real samples.

  17. Use of experimental design for the purge-and-trap-gas chromatography-mass spectrometry determination of methyl tert.-butyl ether, tert.-butyl alcohol and BTEX in groundwater at trace level.

    Science.gov (United States)

    Bianchi, F; Careri, M; Marengo, E; Musci, M

    2002-10-25

    An efficient method for the simultaneous determination of methyl tert.-butyl ether, tert.-butyl alcohol, benzene, toluene, ethylbenzene and xylene isomers in groundwater by purge-and-trap-gas chromatography-mass spectrometry was developed and validated. Experimental design was used to investigate the effects of temperature of extraction, time of extraction and percentage of salt added to the water samples. Regression models and desirability functions were applied to find the experimental conditions providing the highest global extraction yield. Validation was carried out in terms of limits of detection (LOD), limits of quantitation (LOQ), linearity and precision. LOD values ranging from 2.6 to 23 ng l(-1) were achieved, whereas linearity was statistically verified over two orders of magnitude for each compound. Precision was evaluated testing two concentration levels. Good results were obtained both in terms of intra-day repeatability and intermediate precision: RSD% lower than 4.5% at the highest concentration and lower than 13% at the lowest one were calculated for intra-day repeatability. A groundwater sample suspected of contamination by leaking underground petroleum storage tanks was analysed and some of the analytes were detected and quantitated.

  18. Trace determination of organophosphate esters in white wine, red wine, and beer samples using dispersive liquid-liquid microextraction combined with ultra-high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Pang, Long; Yang, Huiqiang; Yang, Peijie; Zhang, Hongzhong; Zhao, Jihong

    2017-08-15

    In this study, dispersive liquid-liquid microextraction coupled with ultra-high-performance liquid chromatography-tandem mass spectrometry was developed for the analysis of five representative organophosphate esters (OPEs) in wine samples. Under optimized conditions, the proposed method resulted in good linearity (R 2 >0.9933) over the range of 0.1-100μgL -1 , with limits of detection (LODs, S/N =3) and quantification (LOQs, S/N =10) in the ranges of 0.48-18.8ngL -1 and 1.58-62.5ngL -1 , respectively. Inter- and intra-assay precisions of RSD% ranged from 3.21% to 6.13% and from 1.69% to 7.63%, respectively. The spiked recoveries of target OPEs from white wine, red wine, and beer samples were in the ranges of 80-122%, 76-120%, and 76-110%, respectively, at two different concentration levels. The total concentrations of five OPEs found in white wine, red wine, and beer samples were in the ranges of 0.29-0.85μgL -1 , 1.00-3.05μgL -1 , and 0.86-1.47μgL -1 , respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Solid-phase extraction in combination with dispersive liquid-liquid microextraction and ultra-high performance liquid chromatography-tandem mass spectrometry analysis: the ultra-trace determination of 10 antibiotics in water samples.

    Science.gov (United States)

    Liang, Ning; Huang, Peiting; Hou, Xiaohong; Li, Zhen; Tao, Lei; Zhao, Longshan

    2016-02-01

    A novel method, solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME), was developed for ultra-preconcentration of 10 antibiotics in different environmental water samples prior to ultra-high performance liquid chromatography-tandem mass spectrometry detection. The optimized results were obtained as follows: after being adjusted to pH 4.0, the water sample was firstly passed through PEP-2 column at 10 mL min(-1), and then methanol was used to elute the target analytes for the following steps. Dichloromethane was selected as extraction solvent, and methanol/acetonitrile (1:1, v/v) as dispersive solvent. Under optimal conditions, the calibration curves were linear in the range of 1-1000 ng mL(-1) (sulfamethoxazole, cefuroxime axetil), 5-1000 ng mL(-1) (tinidazole), 10-1000 ng mL(-1) (chloramphenicol), 2-1000 ng mL(-1) (levofloxacin oxytetracycline, doxycycline, tetracycline, and ciprofloxacin) and 1-400 ng mL(-1) (sulfadiazine) with a good precision. The LOD and LOQ of the method were at very low levels, below 1.67 and 5.57 ng mL(-1), respectively. The relative recoveries of the target analytes were in the range from 64.16% to 99.80% with relative standard deviations between 0.7 and 8.4%. The matrix effect of this method showed a great decrease compared with solid-phase extraction and a significant value of enrichment factor (EF) compared with dispersive liquid-liquid microextraction. The developed method was successfully applied to the extraction and analysis of antibiotics in different water samples with satisfactory results.

  20. Development of a multi-residue analytical methodology based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for screening and trace level determination of pharmaceuticals in surface and wastewaters.

    Science.gov (United States)

    Gros, Meritxell; Petrović, Mira; Barceló, Damiá

    2006-11-15

    This paper describes development, optimization and validation of a method for the simultaneous determination of 29 multi-class pharmaceuticals using off line solid phase extraction (SPE) followed by liquid chromatography-triple quadrupole mass spectrometry (LC-MS-MS). Target compounds include analgesics and non-steroidal anti-inflammatories (NSAIDs), lipid regulators, psychiatric drugs, anti-histaminics, anti-ulcer agent, antibiotics and beta-blockers. Recoveries obtained were generally higher than 60% for both surface and wastewaters, with exception of several compounds that yielded lower, but still acceptable recoveries: ranitidine (50%), sotalol (50%), famotidine (50%) and mevastatin (34%). The overall variability of the method was below 15%, for all compounds and all tested matrices. Method detection limits (MDL) varied between 1 and 30ng/L and from 3 to 160ng/L for surface and wastewaters, respectively. The precision of the method, calculated as relative standard deviation (R.S.D.), ranged from 0.2 to 6% and from 1 to 11% for inter and intra-day analysis, respectively. A detailed study of matrix effects was performed in order to evaluate the suitability of different calibration approaches (matrix-matched external calibration, internal calibration, extract dilution) to reduce analyte suppression or enhancement during instrumental analysis. The main advantages and drawbacks of each approach are demonstrated, justifying the selection of internal standard calibration as the most suitable approach for our study. The developed analytical method was successfully applied to the analysis of pharmaceutical residues in WWTP influents and effluents, as well as in river water. For both, river and wastewaters, the most ubiquitous compounds belonged to the group of anti-inflammatories and analgesics, antibiotics, the lipid regulators being acetaminophen, trimethoprim, ibuprofen, ketoprofen, atenolol, propranolol, mevastatin, carbamazepine and ranitidine the most frequently

  1. Olfactory memory traces in Drosophila.

    Science.gov (United States)

    Berry, Jacob; Krause, William C; Davis, Ronald L

    2008-01-01

    In Drosophila, the fruit fly, coincident exposure to an odor and an aversive electric shock can produce robust behavioral memory. This behavioral memory is thought to be regulated by cellular memory traces within the central nervous system of the fly. These molecular, physiological, or structural changes in neurons, induced by pairing odor and shock, regulate behavior by altering the neurons' response to the learned environment. Recently, novel in vivo functional imaging techniques have allowed researchers to observe cellular memory traces in intact animals. These investigations have revealed interesting temporal and spatial dynamics of cellular memory traces. First, a short-term cellular memory trace was discovered that exists in the antennal lobe, an early site of olfactory processing. This trace represents the recruitment of new synaptic activity into the odor representation and forms for only a short period of time just after training. Second, an intermediate-term cellular memory trace was found in the dorsal paired medial neuron, a neuron thought to play a role in stabilizing olfactory memories. Finally, a long-term protein synthesis-dependent cellular memory trace was discovered in the mushroom bodies, a structure long implicated in olfactory learning and memory. Therefore, it appears that aversive olfactory associations are encoded by multiple cellular memory traces that occur in different regions of the brain with different temporal domains.

  2. Trace Elements in Teeth by ICPMS

    International Nuclear Information System (INIS)

    Zahran, N.F.; Helal, A.I.; Amr, M.A.; Amr, M.A.; Al-saad, K.A.

    2008-01-01

    Teeth are reported to be suitable indicators of trace element exposure from environment and nutritional status. Inductively coupled plasma mass spectrometry (ICP-MS) is used to compare the trace element content of children's primary teeth and adult teeth. Primary teeth are collected from 28 children and 42 adult from non-industrial City. The data are assessed statistically using t-tests. The adult teeth contained significantly greater concentrations of Na, Mg, Al, Fe, Ni, Cu, Sr, Cd, Ba, Pb and U and significantly less Mn, Co, As, Se, Mo and Bi than the children teeth. Additional measurements on adult teeth pulps are performed. Comparison between trace element concentrations in health and caries teeth pulps show that the mean concentrations of Na, Al, K, Cr, Mn, Co, Cu, Zn, Mo, Ag, Bi and U are lower in caries than healthy teeth pulps. On the other hand, the mean concentrations of Mg, Cd and Pb are higher in caries samples than healthy teeth pulps

  3. Proton mass decomposition

    Science.gov (United States)

    Yang, Yi-Bo; Chen, Ying; Draper, Terrence; Liang, Jian; Liu, Keh-Fei

    2018-03-01

    We report the results on the proton mass decomposition and also on the related quark and glue momentum fractions. The results are based on overlap valence fermions on four ensembles of Nf = 2 + 1 DWF configurations with three lattice spacings and volumes, and several pion masses including the physical pion mass. With 1-loop pertur-bative calculation and proper normalization of the glue operator, we find that the u, d, and s quark masses contribute 9(2)% to the proton mass. The quark energy and glue field energy contribute 31(5)% and 37(5)% respectively in the MS scheme at µ = 2 GeV. The trace anomaly gives the remaining 23(1)% contribution. The u, d, s and glue momentum fractions in the MS scheme are consistent with the global analysis at µ = 2 GeV.

  4. Tracing Geothermal Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Michael C. Adams; Greg Nash

    2004-03-01

    Geothermal water must be injected back into the reservoir after it has been used for power production. Injection is critical in maximizing the power production and lifetime of the reservoir. To use injectate effectively the direction and velocity of the injected water must be known or inferred. This information can be obtained by using chemical tracers to track the subsurface flow paths of the injected fluid. Tracers are chemical compounds that are added to the water as it is injected back into the reservoir. The hot production water is monitored for the presence of this tracer using the most sensitive analytic methods that are economically feasible. The amount and concentration pattern of the tracer revealed by this monitoring can be used to evaluate how effective the injection strategy is. However, the tracers must have properties that suite the environment that they will be used in. This requires careful consideration and testing of the tracer properties. In previous and parallel investigations we have developed tracers that are suitable from tracing liquid water. In this investigation, we developed tracers that can be used for steam and mixed water/steam environments. This work will improve the efficiency of injection management in geothermal fields, lowering the cost of energy production and increasing the power output of these systems.

  5. Heat kernel for Newton-Cartan trace anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Auzzi, Roberto [Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Via Musei 41, Brescia, 25121 (Italy); INFN Sezione di Perugia, Via A. Pascoli, Perugia, 06123 (Italy); Nardelli, Giuseppe [Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Via Musei 41, Brescia, 25121 (Italy); TIFPA - INFN, Università di Trento,c/o Dipartimento di Fisica, Povo, TN, 38123 (Italy)

    2016-07-11

    We compute the leading part of the trace anomaly for a free non-relativistic scalar in 2+1 dimensions coupled to a background Newton-Cartan metric. The anomaly is proportional to 1/m, where m is the mass of the scalar. We comment on the implications of a conjectured a-theorem for non-relativistic theories with boost invariance.

  6. Observation of the pulse oximeter trace to estimate systolic blood ...

    African Journals Online (AJOL)

    Background: The estimation of systolic blood pressure by disappearance and reappearance of the pulse oximeter trace during cuff inflation and deflation was compared with non-invasive blood pressure (NIBP) measurement, across the range of body mass index (BMI), during spinal anaesthesia for Caesarean section.

  7. Computer program for optical systems ray tracing

    Science.gov (United States)

    Ferguson, T. J.; Konn, H.

    1967-01-01

    Program traces rays of light through optical systems consisting of up to 65 different optical surfaces and computes the aberrations. For design purposes, paraxial tracings with astigmation and third order tracings are provided.

  8. Trace formulae for arithmetical systems

    International Nuclear Information System (INIS)

    Bogomolny, E.B.; Georgeot, B.; Giannoni, M.J.; Schmit, C.

    1992-09-01

    For quantum problems on the pseudo-sphere generated by arithmetic groups there exist special trace formulae, called trace formulae for Hecke operators, which permit the reconstruction of wave functions from the knowledge of periodic orbits. After a short discussion of this subject, the Hecke operators trace formulae are presented for the Dirichlet problem on the modular billiard, which is a prototype of arithmetical systems. The results of numerical computations for these semiclassical type relations are in good agreement with the directly computed eigenfunctions. (author) 23 refs.; 2 figs

  9. Ultra-trace Measurements in the WAIS Divide 06A Ice Core, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — These data contain the results of gas chromatography mass spectrometry (GC-MS) analysis of 207 samples from the WAIS Divide 06A ice core. The trace gases found in...

  10. Atomic mass spectrometry

    International Nuclear Information System (INIS)

    Sanz-Medel, A.

    1997-01-01

    The elemental inorganic analysis seems to be dominated today by techniques based on atomic spectrometry. After an evaluation of advantages and limitations of using mass analysers (ion detectors) versus conventional photomultipliers (photon detector) a brief review of the more popular techniques of the emerging Atomic Mass spectrometry is carried out. Their huge potential for inorganic trace analysis is such that in the future we could well witness how this end of the century and millennium marked the fall of the photons empire in Analytical Atomic Spectrometry. (Author)

  11. Analysis of trace elements in human hair by PIXE

    International Nuclear Information System (INIS)

    Baptista, G.B.; Montenegro, E.C.; Paschoa, A.S.; Barros Leite, C.V. de.

    1980-10-01

    The PIXE method was applied to the analysis of trace elements in scalp hair using two methods for target preparation. In the first method eigth hair strands each with nearly cylindrical geommetry and approximately the same diameter were selected and placed on an aluminum frame. In the second method a given mass of hair was dissolved with nitric acid and a known amount of strontium was added to the solution and dripped on a membrane filter using a micropipet. The results for the concentrations of trace elements in hair obtained by the two methods are compared and several aspects of the analysis is discussed. (Author) [pt

  12. Ultra trace plutonium isotopic analyse by thermo ionization mass spectrometry

    International Nuclear Information System (INIS)

    Liu Xuemei; Long Kaiming; Yang Tianli

    2008-06-01

    An anion exchange combined with TTA extraction decontamination method was established. The nanogram quantity Plutonium was separated from milligram uranium and the decontamination coefficient achieved 10 7 , the recovery coefficient >95%. The active carbon powder was chosen as the ionization intensifier to increase the plutonium ion flow. Used 6.7 pg Plutonium standard as sample to measured by TIMS and the RSD of the 240 Pu/ 239 Pu ≤3.6%. (authors)

  13. TraceContract: A Scala DSL for Trace Analysis

    Science.gov (United States)

    Barringer, Howard; Havelund, Klaus

    2011-01-01

    In this paper we describe TRACECONTRACT, an API for trace analysis, implemented in the SCALA programming language. We argue that for certain forms of trace analysis the best weapon is a high level programming language augmented with constructs for temporal reasoning. A trace is a sequence of events, which may for example be generated by a running program, instrumented appropriately to generate events. The API supports writing properties in a notation that combines an advanced form of data parameterized state machines with temporal logic. The implementation utilizes SCALA's support for defining internal Domain Specific Languages (DSLs). Furthermore SCALA's combination of object oriented and functional programming features, including partial functions and pattern matching, makes it an ideal host language for such an API.

  14. Measurement of Selected Organic Trace Gases During TRACE-P

    Science.gov (United States)

    Atlas, Elliot

    2004-01-01

    Major goals of the TRACE-P mission were: 1) to investigate the chemical composition of radiatively important gases, aerosols, and their precursors in the Asian outflow over the western Pacific, and 2) to describe and understand the chemical evolution of the Asian outflow as it is transported and mixed into the global troposphere. The research performed as part of this proposal addressed these major goals with a study of the organic chemical composition of gases in the TRACE-P region. This work was a close collaboration with the Blake/Rowland research group at UC-Irvine, and they have provided a separate report for their funded effort.

  15. A Theory of Network Tracing

    Science.gov (United States)

    Acharya, Hrishikesh B.; Gouda, Mohamed G.

    Traceroute is a widely used program for computing the topology of any network in the Internet. Using Traceroute, one starts from a node and chooses any other node in the network. Traceroute obtains the sequence of nodes that occur between these two nodes, as specified by the routing tables in these nodes. Each use of Traceroute in a network produces a trace of nodes that constitute a simple path in this network. In every trace that is produced by Traceroute, each node occurs either by its unique identifier, or by the anonymous identifier"*". In this paper, we introduce the first theory aimed at answering the following important question. Is there an algorithm to compute the topology of a network N from a trace set T that is produced by using Traceroute in network N, assuming that each edge in N occurs in at least one trace in T, and that each node in N occurs by its unique identifier in at least one trace in T? We prove that the answer to this question is "No" if N is an even ring or a general network. However, it is "Yes" if N is a tree or an odd ring. The answer is also "No" if N is mostly-regular, but "Yes" if N is a mostly-regular even ring.

  16. Tracing the cosmic web

    Science.gov (United States)

    Libeskind, Noam I.; van de Weygaert, Rien; Cautun, Marius; Falck, Bridget; Tempel, Elmo; Abel, Tom; Alpaslan, Mehmet; Aragón-Calvo, Miguel A.; Forero-Romero, Jaime E.; Gonzalez, Roberto; Gottlöber, Stefan; Hahn, Oliver; Hellwing, Wojciech A.; Hoffman, Yehuda; Jones, Bernard J. T.; Kitaura, Francisco; Knebe, Alexander; Manti, Serena; Neyrinck, Mark; Nuza, Sebastián E.; Padilla, Nelson; Platen, Erwin; Ramachandra, Nesar; Robotham, Aaron; Saar, Enn; Shandarin, Sergei; Steinmetz, Matthias; Stoica, Radu S.; Sousbie, Thierry; Yepes, Gustavo

    2018-01-01

    The cosmic web is one of the most striking features of the distribution of galaxies and dark matter on the largest scales in the Universe. It is composed of dense regions packed full of galaxies, long filamentary bridges, flattened sheets and vast low-density voids. The study of the cosmic web has focused primarily on the identification of such features, and on understanding the environmental effects on galaxy formation and halo assembly. As such, a variety of different methods have been devised to classify the cosmic web - depending on the data at hand, be it numerical simulations, large sky surveys or other. In this paper, we bring 12 of these methods together and apply them to the same data set in order to understand how they compare. In general, these cosmic-web classifiers have been designed with different cosmological goals in mind, and to study different questions. Therefore, one would not a priori expect agreement between different techniques; however, many of these methods do converge on the identification of specific features. In this paper, we study the agreements and disparities of the different methods. For example, each method finds that knots inhabit higher density regions than filaments, etc. and that voids have the lowest densities. For a given web environment, we find a substantial overlap in the density range assigned by each web classification scheme. We also compare classifications on a halo-by-halo basis; for example, we find that 9 of 12 methods classify around a third of group-mass haloes (i.e. Mhalo ∼ 1013.5 h-1 M⊙) as being in filaments. Lastly, so that any future cosmic-web classification scheme can be compared to the 12 methods used here, we have made all the data used in this paper public.

  17. [Trace elements of bone tumors].

    Science.gov (United States)

    Kalashnikov, V M; Zaĭchik, V E; Bizer, V A

    1983-01-01

    Due to activation analysis involving the use of neutrons from a nuclear reactor, the concentrations of 11 trace elements: scandium, iron, cobalt, mercury, rubidium, selenium, silver, antimony, chrome, zinc and terbium in intact bone and skeletal tumors were measured. 76 specimens of bioptates and resected material of operations for bone tumors and 10 specimens of normal bone tissue obtained in autopsies of cases of sudden death were examined. The concentrations of trace elements and their dispersion patterns in tumor tissue were found to be significantly higher than those in normal bone tissue. Also, the concentrations of some trace elements in tumor differed significantly from those in normal tissue; moreover, they were found to depend on the type and histogenesis of the neoplasm.

  18. Trace elements in human milk

    Energy Technology Data Exchange (ETDEWEB)

    Parr, R M [International Atomic Energy Agency, Vienna (Austria). Div. of Life Sciences

    1983-06-01

    Trace elements are those elements having a concentration lower than 10 ppm in body fluids or tissues. A total of 24 elements, both trace and minor elements, present in human milk have been analysed in this study, employing neutron activation analysis and absorption spectroscopy. The analyses have been carried out collaboratively by several different laboratories and the Agency which has also served as a coordinating centre. Although the evaluation of the results, altogether 8500 separate values, is still in progress, enough evidence is already available, however, to show some very interesting differences between different study areas and, in some cases, between different socio-economic groups within a single country. The main value of these data will probably be to throw new light on the nutritional requirements of young babies for trace elements.

  19. Manual tracing versus smartphone application (app) tracing: a comparative study.

    Science.gov (United States)

    Sayar, Gülşilay; Kilinc, Delal Dara

    2017-11-01

    This study aimed to compare the results of conventional manual cephalometric tracing with those acquired with smartphone application cephalometric tracing. The cephalometric radiographs of 55 patients (25 females and 30 males) were traced via the manual and app methods and were subsequently examined with Steiner's analysis. Five skeletal measurements, five dental measurements and two soft tissue measurements were managed based on 21 landmarks. The durations of the performances of the two methods were also compared. SNA (Sella, Nasion, A point angle) and SNB (Sella, Nasion, B point angle) values for the manual method were statistically lower (p < .001) than those for the app method. The ANB value for the manual method was statistically lower than that of app method. L1-NB (°) and upper lip protrusion values for the manual method were statistically higher than those for the app method. Go-GN/SN, U1-NA (°) and U1-NA (mm) values for manual method were statistically lower than those for the app method. No differences between the two methods were found in the L1-NB (mm), occlusal plane to SN, interincisal angle or lower lip protrusion values. Although statistically significant differences were found between the two methods, the cephalometric tracing proceeded faster with the app method than with the manual method.

  20. Tracing a planar algebraic curve

    International Nuclear Information System (INIS)

    Chen Falai; Kozak, J.

    1994-09-01

    In this paper, an algorithm that determines a real algebraic curve is outlined. Its basic step is to divide the plane into subdomains that include only simple branches of the algebraic curve without singular points. Each of the branches is then stably and efficiently traced in the particular subdomain. Except for the tracing, the algorithm requires only a couple of simple operations on polynomials that can be carried out exactly if the coefficients are rational, and the determination of zeros of several polynomials of one variable. (author). 5 refs, 4 figs

  1. Trace elements in brazilian soils

    International Nuclear Information System (INIS)

    Rocha, Geraldo Cesar

    1995-01-01

    A literature revision on trace elements (Zn, B, Mn, Mo, Cu, Fe, and Cl) in Brazilian soils was prepared, with special attention to the chemical form and range in the soil, extraction methods and correlation of the amount in soils with soil properties

  2. Digital Traces of Information Systems

    DEFF Research Database (Denmark)

    Hedman, Jonas; Srinivasan, Nikhil; Lindgren, Rikard

    2013-01-01

    . This disconcerting result suggests that IS researchers must pay more attention to the changing landscape of data sources. To motivate and guide fellow colleagues to establish the credibility and reliability of digital traces, we develop a future research agenda that covers both opportunities in theory generation...

  3. Phenomenological mass matrices with a democratic warp

    International Nuclear Information System (INIS)

    Kleppe, A.

    2018-01-01

    Taking into account all available data on the mass sector, we obtain unitary rotation matrices that diagonalize the quark matrices by using a specific parametrization of the Cabibbo-Kobayashi-Maskawa mixing matrix. In this way, we find mass matrices for the up- and down-quark sectors of a specific, symmetric form, with traces of a democratic texture.

  4. Determination of iodine at ppt level in a nitric acid medium by inductively coupled plasma sector field mass spectrometry: influence of the chemical forms; Etude de la determination de traces d'iode en solution par spectrometrie de masse a secteur magnetique utilisant un plasma a couplage inductif comme source d'ionisation: influence de la forme chimique

    Energy Technology Data Exchange (ETDEWEB)

    Langlois, B

    2001-07-01

    Inductively Coupled Plasma Sector Field Mass Spectrometry (ICP/SFMS) was used to determine several chemical forms of iodine, at ppt level, in a nitric acid media. Ascorbic acid was added as a reducing agent in order to maintain iodine as iodide. In a preliminary approach, the influence of the chemical form was studied by comparing inorganic iodine (NaI) and organic iodine (CH3I). Different signal responses were observed. With a conventional sample introduction system, sensitivities obtained for iodo-methane could differ by a factor of 5. This was not caused by a problem of atomization or by a change in the ionization efficiency of the iodo-compound into the plasma. The low volatilization temperature of iodo-methane (315.5 K) seemed to be the main explanation of this phenomena. Actually, nebulization resulted in the volatilization of a 2% nitric acid solution containing iodo-methane. As a result, the transport efficiency of iodo-methane between the nebulizer and the torch was approaching 100%. A Direct Injection High Efficiency Nebulizer (DIHEN) allowed us to minimize the behavior difference between the two iodine species, but the sensitivity ratio was inverted and still differed by 20 - 40%. Moreover, the association of a guard electrode and the direct injection system was studied in order to apply these equipments to the determination of iodine. This association allowed us to improve the sensitivity by a factor of 10 and to minimize memory effects, when compared with a conventional system. Further studies indicated that signal responses obtained with different iodine-containing species, except for iodo-methane, were found to be similar. (author)

  5. Gas Chromatic Mass Spectrometer

    Science.gov (United States)

    Wey, Chowen

    1995-01-01

    Gas chromatograph/mass spectrometer (GC/MS) used to measure and identify combustion species present in trace concentration. Advanced extractive diagnostic method measures to parts per billion (PPB), as well as differentiates between different types of hydrocarbons. Applicable for petrochemical, waste incinerator, diesel transporation, and electric utility companies in accurately monitoring types of hydrocarbon emissions generated by fuel combustion, in order to meet stricter environmental requirements. Other potential applications include manufacturing processes requiring precise detection of toxic gaseous chemicals, biomedical applications requiring precise identification of accumulative gaseous species, and gas utility operations requiring high-sensitivity leak detection.

  6. Trace Metals Bioaccumulation Potentials of Three Indigenous ...

    African Journals Online (AJOL)

    User

    grasses as bioaccumulators of trace metals from polluted soils. Seeds of ... transfer factor (TF) showed that Zn was the most bioaccumulated trace metals by all the grasses followed by. Pb, Mn ... was used to de-contaminate copper (Cu) and.

  7. Trace and ultratrace level elemental and speciation analysis

    International Nuclear Information System (INIS)

    Arunachalam, J.

    2012-01-01

    Accurate determination of elements present at parts per million and billion levels in various matrices is a growing requirement in different fields. In environmental sciences various trace elements need to be analyzed so as establish the dispersal models of pollutants or the adequacy of effluent treatment prior to discharge into water bodies. The issues of bioaccumulation and magnification are important in aquatic systems. In nutrition and biochemistry one has to establish the bio-availability of essential and toxic elemental species as toxic elements prevent assimilation of essential elements. Fission and fusion technologies use a variety of structural materials requiring many trace elements to be present at levels strictly below the specified levels. Ultra-pure bulk semiconductor materials are required for fabrication devices. In metallurgy and materials sciences too, various trace elements are known to influence the properties. In the emerging fields like nanotechnology, it is necessary to understand the passage and accumulation of nano-particles inside the cells, through trace analysis. Many analytical techniques exist which can provide the concentration information in the bulk materials with good accuracy. They include ICP-AES, FAAS, and ICP-MS, which are solution based techniques. Direct solid state analytical techniques are Glow Discharge Mass Spectrometry (GDMS) and XRF. Accelerator based ion-beam analysis techniques can provide information on concentration and depth profiles of different elements in layered structures. Hyphenated techniques such as HPLC/lC-ICPMS, are helpful in identifying various chemical oxidation states in which a given element might be present in a matrix, which is termed as speciation analysis. This presentation will include the existing analytical competencies and the laboratory requirements for trace and ultra trace element elemental and speciation analyses and their applications. (author)

  8. Distributed trace using central performance counter memory

    Science.gov (United States)

    Satterfield, David L.; Sexton, James C.

    2013-01-22

    A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

  9. Trace element measurement for assessment of dog food safety.

    Science.gov (United States)

    De Nadai Fernandes, Elisabete A; Elias, Camila; Bacchi, Márcio Arruda; Bode, Peter

    2018-01-01

    The quality of dog diets depends on adequate ingredients capable of providing optimal nutrition and free of contaminants, for promoting long-term health. Trace elements in 95 samples of dry food for dog puppies (n = 32) and adults (n = 63) of various brands were measured using instrumental neutron activation analysis (INAA). The mass fractions of most elements were within the permissible limits for dogs. Aluminum, antimony, and uranium presented fairly high levels in some samples, which may imply health risks. Aluminum mass fractions ranged from brand, super-premium dog food. Antimony mass fractions ranged up to 5.14 mg/kg, with the highest values measured in six samples of dog food from the same producer. The mass fractions of uranium was found up to 4 mg/kg in commercial brands from five different producers.

  10. Semiclassical structure of trace formulas

    International Nuclear Information System (INIS)

    Littlejohn, R.G.

    1990-01-01

    Trace formulas provide the only general relations known connecting quantum mechanics with classical mechanics in the case that the classical motion is chaotic. In particular, they connect quantal objects such as the density of states with classical periodic orbits. In this paper, several trace formulas, including those of Gutzwiller, Balian and Bloch, Tabor, and Berry, are examined from a geometrical standpoint. New forms of the amplitude determinant in asymptotic theory are developed as tools for this examination. The meaning of caustics in these formulas is revealed in terms of intersections of Lagrangian manifolds in phase space. The periodic orbits themselves appear as caustics of an unstable kind, lying on the intersection of two Lagrangian manifolds in the appropriate phase space. New insight is obtained into the Weyl correspondence and the Wigner function, especially their caustic structures

  11. Measuring Trace Hydrocarbons in Silanes

    Science.gov (United States)

    Lesser, L. A.

    1984-01-01

    Technique rapid and uses standard analytical equipment. Silane gas containing traces of hydrocarbons injected into carrier gas of moist nitrogen having about 0.2 percent water vapor. Carrier, water and silane pass through short column packed with powdered sodium hydroxide which combines moisture and silane to form nonvolatile sodium silicate. Carrier gas free of silane but containing nonreactive hydrocarbons, pass to silica-gel column where chromatographic separation takes place. Hydrocarbons measured by FID.

  12. Olfactory memory traces in Drosophila

    OpenAIRE

    Berry, Jacob; Krause, William C.; Davis, Ronald L.

    2008-01-01

    In Drosophila the fruit fly, coincident exposure to an odor and an aversive electric shock can produce robust behavioral memory. This behavioral memory is thought to be regulated by cellular memory traces within the central nervous system of the fly. These molecular, physiological or structural changes in neurons, induced by pairing odor and shock, regulate behavior by altering the neurons’ response to the learned environment. Recently, novel in vivo functional imaging techniques have allowed...

  13. Trace element emissions from coal

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-09-15

    Trace elements are emitted during coal combustion. The quantity, in general, depends on the physical and chemical properties of the element itself, the concentration of the element in the coal, the combustion conditions and the type of particulate control device used, and its collection efficiency as a function of particle size. Some trace elements become concentrated in certain particle streams following combustion such as bottom ash, fly ash, and flue gas particulate matter, while others do not. Various classification schemes have been developed to describe this partitioning behaviour. These classification schemes generally distinguish between: Class 1: elements that are approximately equally concentrated in the fly ash and bottom ash, or show little or no fine particle enrichment, examples include Mn, Be, Co and Cr; Class 2: elements that are enriched in the fly ash relative to bottom ash, or show increasing enrichment with decreasing particle size, examples include As, Cd, Pb and Sb; Class 3: elements which are emitted in the gas phase (primarily Hg (not discussed in this review), and in some cases, Se). Control of class 1 trace elements is directly related to control of total particulate matter emissions, while control of the class 2 elements depends on collection of fine particulates. Due to the variability in particulate control device efficiencies, emission rates of these elements can vary substantially. The volatility of class 3 elements means that particulate controls have only a limited impact on the emissions of these elements.

  14. Trace explosives sensor testbed (TESTbed)

    Science.gov (United States)

    Collins, Greg E.; Malito, Michael P.; Tamanaha, Cy R.; Hammond, Mark H.; Giordano, Braden C.; Lubrano, Adam L.; Field, Christopher R.; Rogers, Duane A.; Jeffries, Russell A.; Colton, Richard J.; Rose-Pehrsson, Susan L.

    2017-03-01

    A novel vapor delivery testbed, referred to as the Trace Explosives Sensor Testbed, or TESTbed, is demonstrated that is amenable to both high- and low-volatility explosives vapors including nitromethane, nitroglycerine, ethylene glycol dinitrate, triacetone triperoxide, 2,4,6-trinitrotoluene, pentaerythritol tetranitrate, and hexahydro-1,3,5-trinitro-1,3,5-triazine. The TESTbed incorporates a six-port dual-line manifold system allowing for rapid actuation between a dedicated clean air source and a trace explosives vapor source. Explosives and explosives-related vapors can be sourced through a number of means including gas cylinders, permeation tube ovens, dynamic headspace chambers, and a Pneumatically Modulated Liquid Delivery System coupled to a perfluoroalkoxy total-consumption microflow nebulizer. Key features of the TESTbed include continuous and pulseless control of trace vapor concentrations with wide dynamic range of concentration generation, six sampling ports with reproducible vapor profile outputs, limited low-volatility explosives adsorption to the manifold surface, temperature and humidity control of the vapor stream, and a graphical user interface for system operation and testing protocol implementation.

  15. Traces et espaces de consommation

    Directory of Open Access Journals (Sweden)

    Franck Cochoy

    2016-10-01

    Full Text Available L’avènement des technologies numériques mobiles contribue à une évolution des modalités de distribution et de consommation. Le présent article porte sur l’usage des QR-codes, ces codes-barres bidimensionnels qui offrent à tout usager équipé d’un smartphone l’accès à des contenus commerciaux en ligne. Ils participent à l’Internet des objets et donc au couplage entre espace physique et univers numérique. Ils permettent aussi la collecte de traces numériques porteuses de sens pour les professionnels mais aussi pour les sciences sociales. Grâce à ces traces, on peut comprendre les nouveaux liens marchands tissés entre l’espace physique et le développement de flux informationnels continus. À partir de l’analyse des traces enregistrées à l’occasion de la visite des QR-codes apposés sur trois produits alimentaires (une boîte de sel, une barre chocolatée, une bouteille d’eau, notre enquête s’attache à expliciter les enjeux théoriques, méthodologiques et analytiques du processus de numérisation de l’espace de mobilité physique marchand.

  16. The Fate of Trace Contaminants in a Crewed Spacecraft Cabin Environment

    Science.gov (United States)

    Perry, Jay L.; Kayatin, Matthew J.

    2016-01-01

    Trace chemical contaminants produced via equipment offgassing, human metabolic sources, and vehicle operations are removed from the cabin atmosphere by active contamination control equipment and incidental removal by other air quality control equipment. The fate of representative trace contaminants commonly observed in spacecraft cabin atmospheres is explored. Removal mechanisms are described and predictive mass balance techniques are reviewed. Results from the predictive techniques are compared to cabin air quality analysis results. Considerations are discussed for an integrated trace contaminant control architecture suitable for long duration crewed space exploration missions.

  17. study on trace contaminants control assembly for sealed environment chamber

    Science.gov (United States)

    Pang, L. P.; Wang, J.; Liu, L. K.; Liu, H.

    The biological and Physicochemical P C life support technologies are all important parts to establish a human Closed Ecological Life Support System CELSS for long-duration mission The latter has the advantages of lower power consumption lower mass and higher efficiency therefore researchers often incorporate the use of biological systems with P C life support technologies to continuously recycle air water and part of the solid waste stream generated such as the Russian BLSS and the NASA-sponsored Lunar-Mars Life Support Test Project LMLSTP In short these tests were very successful in integrating biological and P C life support technologies for long-duration life support Therefore we should use a combination of integrated biological with P C life support technologies in a human CELSS Human construction materials plants animals and soils release much trace toxic gases in a CELSS and they will inhibit plant growth and badly affect human health when their concentrations rise over their threshold levels The effect of biological trace contaminant control technologies is slower especially for a human sealed chamber because human produce much more methane and other contaminants A regenerative Trace Contaminant Control Subsystem TCCS with P C technology is a more important part in this case to control quickly the airborne contaminants levels and assure human in good condition in a sealed chamber This paper describes a trace contaminant control test facility incorporated a 8 m3 sealed environment chamber a regenerative TCCS with P C

  18. An image analyzer system for the analysis of nuclear traces

    International Nuclear Information System (INIS)

    Cuapio O, A.

    1990-10-01

    Inside the project of nuclear traces and its application techniques to be applied in the detection of nuclear reactions of low section (non detectable by conventional methods), in the study of accidental and personal neutron dosemeters, and other but, are developed. All these studies are based on the fact that the charged particles leave latent traces of dielectric that if its are engraved with appropriate chemical solutions its are revealed until becoming visible to the optical microscope. From the analysis of the different trace forms, it is possible to obtain information of the characteristic parameters of the incident particles (charge, mass and energy). Of the density of traces it is possible to obtain information of the flow of the incident radiation and consequently of the received dose. For carry out this analysis has been designed and coupled different systems, that it has allowed the solution of diverse outlined problems. Notwithstanding it has been detected that to make but versatile this activity is necessary to have an Image Analyzer System that allow us to digitize, to process and to display the images with more rapidity. The present document, presents the proposal to carry out the acquisition of the necessary components for to assembling an Image Analyzing System, like support to the mentioned project. (Author)

  19. Trace metal speciation: Finally, correctly addressing trace metal issues

    International Nuclear Information System (INIS)

    Donard, O.F.X.

    2001-01-01

    The history of the development of trace metal speciation was discussed and the reasons behind the relatively slow widespread acceptance of its importance were presented. Partially, this was due to the lack of availability of commercial instrumentation and partly to the drive towards improving sensitivity in analytical chemistry which had focused attention on total concentration determinations. The sophistication and control of analytical instrumentation is now such that the spotlight must be turned onto the chemical species of an element present in a sample since this is what governs its behaviour in the biosphere. Indeed, several companies are currently considering the introduction of instrumentation specifically designed for metal species determination

  20. Volatile characteristic of trace elements during microwave pyrolysis of oil shale

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Jing-ru; Wang, Qing; Kong, Ling-wen; Bai, Zhang [Northeast Dianli Univ., Jilin (China). Engineering Research Centre

    2013-07-01

    Oil shale is abundant in the world. Today, the industry of oil shale retorting for producing shale oil is developing owing to high price of oil in the world. In order to study migratory behavior of trace elements in oil shale at microwave pyrolysis, tests were performed in laboratory with oil shale of the Huadian deposit of China at different powers from 400 to 700 W. The trace elements As, Cd, Hg, Mo, Pb, Se, Cr, Cu, Ni, V, Zn, Ba, Co, Mn present in oil shale and shale char were determined by the inductively coupled plasma-mass spectrometry (ICP-MS). By comparing the content of trace elements in oil shale and shale char, distribution characteristics of trace elements at retorting were studied. The overall trends of volatile ratio of trace elements are ascending with higher microwave power and higher than the conventional pyrolysis. The differences in the volatile ratio indicate that the trace elements investigated are bound with the oil shale kerogen and its mineral matter in different manner. So Float-sink experiments (FSE) were performed on oil shale. Huadian oil shale has more included mineral. The volatilization of organic matter is not the main reason for the volatilization of trace elements in oil shale. The trace elements combined with the mineral elements may be also certain volatility.

  1. Distribution of Selected Trace Elements in the Bayer Process

    Directory of Open Access Journals (Sweden)

    Johannes Vind

    2018-05-01

    Full Text Available The aim of this work was to achieve an understanding of the distribution of selected bauxite trace elements (gallium (Ga, vanadium (V, arsenic (As, chromium (Cr, rare earth elements (REEs, scandium (Sc in the Bayer process. The assessment was designed as a case study in an alumina plant in operation to provide an overview of the trace elements behaviour in an actual industrial setup. A combination of analytical techniques was used, mainly inductively coupled plasma mass spectrometry and optical emission spectroscopy as well as instrumental neutron activation analysis. It was found that Ga, V and As as well as, to a minor extent, Cr are principally accumulated in Bayer process liquors. In addition, Ga is also fractionated to alumina at the end of the Bayer processing cycle. The rest of these elements pass to bauxite residue. REEs and Sc have the tendency to remain practically unaffected in the solid phases of the Bayer process and, therefore, at least 98% of their mass is transferred to bauxite residue. The interest in such a study originates from the fact that many of these trace constituents of bauxite ore could potentially become valuable by-products of the Bayer process; therefore, the understanding of their behaviour needs to be expanded. In fact, Ga and V are already by-products of the Bayer process, but their distribution patterns have not been provided in the existing open literature.

  2. Trace emissions from gaseous combustion

    Energy Technology Data Exchange (ETDEWEB)

    Seebold, J.G. [Chevron Research and Technology Co., Richmond, CA (United States)

    2000-07-01

    The U.S. Clean Air Act (CAA) was amended in 1990 to include the development of maximum achievable control technology (MACT) emission standards for hazardous air pollutants (HAPs) for certain stationary sources by November 2000. MACT emissions standards would affect process heaters and industrial boilers since combustion processes are a potential source for many air toxins. The author noted that one of the problems with MACT is the lack of a clear solid scientific footing which is needed to develop environmentally responsible regulations. In order to amend some of these deficiencies, a 4-year, $7 million research project on the origin and fate of trace emissions in the external combustion of gaseous hydrocarbons was undertaken in a collaborative effort between government, universities and industry. This collaborative project entitled the Petroleum Environmental Research Forum (PERF) Project 92-19 produced basic information and phenomenological understanding in two important areas, one basic and one applied. The specific objectives of the project were to measure emissions while operating different full-scale burners under various operating conditions and then to analyze the emission data to identify which operating conditions lead to low air toxic emissions. Another objective was to develop new chemical kinetic mechanisms and predictive models for the formation of air toxic species which would explain the origin and fate of these species in process heaters and industrial boilers. It was determined that a flame is a very effective reactor and that trace emissions from a typical gas-fired industry burner are very small. An unexpected finding was that trace emissions are not affected by hydrocarbon gaseous fuel composition, nor by the use of ultra low nitrous oxide burners. 2 refs., 8 figs.

  3. Tracing Utopia in 'Utopia Station'

    DEFF Research Database (Denmark)

    Schwarzbart, Judith

    This paper will discuss how avant-garde rhetoric and working methods are used to rethink exhibition-making in the wake of the ‘relational aesthetics’ and visual art of the 90s. With Utopia Station curated by Molly Nesbit, Hans Ulrich Obrist, and Rirkrit Tiravanija as key example, we will look...... at the many layers of discourse, ‘thinking-in-process’ and collaboration. These processes led to particular presentational formats (display) and architectural frameworks for activities, and gave way to a variety of other material and situated performative modes of audience encounters. Here, we can trace avant...

  4. Trace elements in human pituitary

    International Nuclear Information System (INIS)

    Kanabrocki, E.L.; Greco, J.; Graham, L.A.; Kaplan, E.; Rubnitz, M.E.; Oester, Y.T.; Brar, S.; Gustafson, P.S.; Nelson, D.M.; Molinari, F.; Moore, C.E.; Kanabrocki, J.A.

    1976-01-01

    Neutron activation analysis was used to determine several trace elements in human pituitaries from adult subjects aged 42 to 83 years who had died of ischemic heart disease, carcinoma and cirrhosis of the liver. None of these subjects suffered from mental disease. The concentrations of Fe, Zn, Rb, Se, Br, Cr, Hg, Cs and Co in dried tissue showed no correlation with the diseases, and the results may therefore be representative of the general population. These elements may play a very fundamental role in pituitary function. (U.K.)

  5. Concurrent Use of H.sub.3./sub.O.sup.+./sup., NO.sup.+./sup., and O.sub.2./sub..sup.+./sup. Precursor Ions for the Detection and Quantification of Diverse Trace Gases in the Presence of Air and Breath by Selected Ion-Flow Tube mass Spectrometry

    Czech Academy of Sciences Publication Activity Database

    Smith, D.; Diskin, A. M.; Yufeng, Ji.; Španěl, Patrik

    2001-01-01

    Roč. 209, č. 1 (2001), s. 81-97 ISSN 1387-3806 R&D Projects: GA ČR GA203/97/P130 Institutional research plan: CEZ:AV0Z4040901 Keywords : SIFT-MS * trace-gas analysis * chemical ionization Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.176, year: 2001

  6. Mass discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Broeckman, A. [Rijksuniversiteit Utrecht (Netherlands)

    1978-12-15

    In thermal ionization mass spectrometry the phenomenon of mass discrimination has led to the use of a correction factor for isotope ratio-measurements. The correction factor is defined as the measured ratio divided by the true or accepted value of this ratio. In fact this factor corrects for systematic errors of the whole procedure; however mass discrimination is often associated just with the mass spectrometer.

  7. Negative mass

    International Nuclear Information System (INIS)

    Hammond, Richard T

    2015-01-01

    Some physical aspects of negative mass are examined. Several unusual properties, such as the ability of negative mass to penetrate any armor, are analysed. Other surprising effects include the bizarre system of negative mass chasing positive mass, naked singularities and the violation of cosmic censorship, wormholes, and quantum mechanical results as well. In addition, a brief look into the implications for strings is given. (paper)

  8. Simultaneous mass detection for direct inlet mass spectrometry

    International Nuclear Information System (INIS)

    Gordon, R.L.

    1979-05-01

    The evolution of analytical techniques for application in trace analysis has led to interest in practical methods for real-time monitoring. Direct inlet mass spectrometry (DIMS) has been the subject of considerable activity in recent years. A DIMS instrument is described which consists of an inlet system designed to permit particles entrained in the inlet air stream to strike a hot, oxidized rhenium filament which serves as a surface ionization source. A mass analyzer and detection system then permits identification of the elemental composition of particulates which strike the filament

  9. Nominal Mass?

    Science.gov (United States)

    Attygalle, Athula B; Pavlov, Julius

    2017-08-01

    The current IUPAC-recommended definition of the term "nominal mass," based on the most abundant naturally occurring stable isotope of an element, is flawed. We propose that Nominal mass should be defined as the sum of integer masses of protons and neutrons in any chemical species. In this way, all isotopes and isotopologues can be assigned a definitive identifier. Graphical Abstract ᅟ.

  10. Trace Elements in Cardiovascular Diseases

    Energy Technology Data Exchange (ETDEWEB)

    Masironi, R. [Cardiovascular Diseases Unit, World Health Organization, Geneva (Switzerland)

    1970-07-01

    Cardiovascular diseases are the leading cause of death in industrialized countries. Their incidence increases, apparently, as a, function of technological progress so that in the future they may become a major public health problem in developing countries too. Early diagnosis and prevention are the tools best suited to curb such an alarming trend, but our knowledge of these topics is unsatisfactory, Valuable information would be obtained through a systematic investigation of trace elements in relation to cardiovascular function and to various types of cardiovascular diseases. Such studies would provide clues to the following questions: 1. Why does the incidence and type of cardiovascular disease differ from one country to another? May this be related to differences in tissue mineral concentrations among various population groups? 2. Which trace elements if any are beneficial to cardiovascular health, and which are harmful ones that may act as aetiological agents for some cardiovascular diseases? 3. Is it possible to utilize measurements of mineral element concentration for diagnostic purposes in cardiovascular disease? (author)

  11. Brain trace elements and aging

    International Nuclear Information System (INIS)

    Hebbrecht, Geert; Maenhaut, Willy; Reuck, Jacques de

    1999-01-01

    Degenerative mechanisms involved in the aging process of the brain are to a certain extent counteracted by repair mechanisms. In both degenerative and recovery processes, trace elements are involved. The present study focused on the role of two minor (i.e., K and Ca) and six trace elements (i.e., Mn, Fe, Cu, Zn, Se and Rb) in the aging process. The elements were determined by PIXE in cerebral cortex and white matter, basal ganglia, brainstem and cerebellar cortex of 18 postmortem human brains, from persons without a history of neurologic or psychiatric disease who deceased between the age of 7 and 79. This age range allowed us to study the relationship between elemental concentrations and age. The most prominent findings were a concentration decrease for K and Rb and a concentration increase for the elements Ca, Fe, Zn and Se. The study supports recent findings that Ca and Fe are involved in brain degenerative processes initiated by oxygen free radicals, whereas Zn and Se are involved in immunological reactions counteracting the aging process

  12. Subcellular trace element distribution in Geosiphon pyriforme

    International Nuclear Information System (INIS)

    Maetz, Mischa; Schuessler, Arthur; Wallianos, Alexandros; Traxel, Kurt

    1999-01-01

    Geosiphon pyriforme is a unique endosymbiotic consortium consisting of a soil dwelling fungus and the cyanobacterium Nostoc punctiforme. At present this symbiosis becomes very interesting because of its phylogenetic relationship to the arbuscular mycorrhizal (AM) fungi. Geosiphon pyriforme could be an important model system for these obligate symbiotic fungi, which supply 80-90% of all land plant species with nutrients, in particular phosphorous and trace elements. Combined PIXE and STIM analyses of the various compartments of Geosiphon give hints for the matter exchange between the symbiotic partners and their environment and the kind of nutrient storage and acquisition, in particular related to nitrogen fixation and metabolism. To determine the quality of our PIXE results we analysed several geological and biological standards over a time period of three years. This led to an overall precision of about 6% and an accuracy of 5-10% for nearly all detectable elements. In combination with the correction model for the occurring mass loss during the analyses this holds true even for biological targets

  13. Subcellular trace element distribution in Geosiphon pyriforme

    Energy Technology Data Exchange (ETDEWEB)

    Maetz, Mischa E-mail: mischa.maetz@mpi-hd.mpg.de; Schuessler, Arthur; Wallianos, Alexandros; Traxel, Kurt

    1999-04-02

    Geosiphon pyriforme is a unique endosymbiotic consortium consisting of a soil dwelling fungus and the cyanobacterium Nostoc punctiforme. At present this symbiosis becomes very interesting because of its phylogenetic relationship to the arbuscular mycorrhizal (AM) fungi. Geosiphon pyriforme could be an important model system for these obligate symbiotic fungi, which supply 80-90% of all land plant species with nutrients, in particular phosphorous and trace elements. Combined PIXE and STIM analyses of the various compartments of Geosiphon give hints for the matter exchange between the symbiotic partners and their environment and the kind of nutrient storage and acquisition, in particular related to nitrogen fixation and metabolism. To determine the quality of our PIXE results we analysed several geological and biological standards over a time period of three years. This led to an overall precision of about 6% and an accuracy of 5-10% for nearly all detectable elements. In combination with the correction model for the occurring mass loss during the analyses this holds true even for biological targets.

  14. Canadian trace emissions project management : phase 2

    International Nuclear Information System (INIS)

    Lajeunesse, J.J.G.

    1997-12-01

    A comprehensive emission study was carried out at Nova Scotia Power's Lingan generating station in which pulverized coal, bottom ash, bottom ash cooling water, fly ash and flue gas were sampled and analyzed for organic and inorganic priority substances. The sampling was done according to the recommended standard of sampling provided by the Canadian Electricity Association's 1992 report entitled 'Trace Emission Project Management : phase 1'. The objectives of this emission study were to show how priority substances are transformed and partitioned within the various process streams in a modern pulverized coal-fired utility boiler and to determine the type and emission rate of various priority substances in the flue gas. An emission data set was prepared in PISCES format, and the data was used to evaluate the effectiveness of the electrostatic precipitator for controlling the emissions of these priority substances. All but five of the elements tracked in the report had mass balances from 90 per cent to 112 per cent. The five elements for which such closure could not be achieved were zinc, mercury, selenium, chlorine and bromine.The data set produced was used to evaluate the Ontario Hydro 640 MJ/h pilot scale combustor and FACT mathematical models. 39 refs., 32 tabs., 10 figs., 2 appendices

  15. Diagnosing MOV problems using comparative trace analysis

    International Nuclear Information System (INIS)

    Leon, R.L.

    1992-01-01

    The paper presents the concept of comparative trace analysis and shows it to be very effective in diagnosing motor operated valve (MOV) problems. Comparative trace analysis is simply the process of interpreting simultaneously gathered traces, each presenting a different perspective on the same series of events. The opening and closing of a motor operated valve is such a series of events. The simultaneous traces are obtained using Liberty Technologies' Valve Operation Test and Evaluation System (VOTES)reg-sign. The traces include stem thrust, motor current, motor power factor, motor power, switch actuations, vibration in three different frequency bands, spring pack displacement, and spring pack force. Spare and auxiliary channels enable additional key parameters to be measured, such as differential pressure and stem displacement. Though not specifically illustrated in this paper, the VOTES system also provides for FFT analysis on all traces except switches

  16. RAY TRACING IMPLEMENTATION IN JAVA PROGRAMMING LANGUAGE

    OpenAIRE

    Aybars UĞUR; Mustafa TÜRKSEVER

    2002-01-01

    In this paper realism in computer graphics and components providing realism are discussed at first. It is mentioned about illumination models, surface rendering methods and light sources for this aim. After that, ray tracing which is a technique for creating two dimensional image of a three-dimensional virtual environment is explained briefly. A simple ray tracing algorithm was given. "SahneIzle" which is a ray tracing program implemented in Java programming language which ...

  17. Trace maps of general substitutional sequences

    International Nuclear Information System (INIS)

    Kolar, M.; Nori, F.

    1990-01-01

    It is shown that for arbitrary n, there exists a trace map for any n-letter substitutional sequence. Trace maps are explicitly obtained for the well-known circle and Rudin-Shapiro sequences which can be defined by means of substitution rules on three and four letters, respectively. The properties of the two trace maps and their consequences for various spectral properties are briefly discussed

  18. The transition region and coronal explorer (TRACE)

    Science.gov (United States)

    Title, Alan; Bruner, M.; Jurcevich, B.; Lemen, J.; Strong, K.; Tarbell, Ted; Wolfson, C. Jacob; Golub, L.; Bookbinder, J.; Fisher, R.

    1995-01-01

    The transition region and coronal explorer (TRACE) NASA small explorer mission and instrument are presented. The TRACE scientific investigation explores the relationships between fine-scale magnetic fields and the associated solar plasma structures. The instrument collects images of solar plasmas at temperatures from 10(exp 4) to 10(exp 7) K with one arcsec spatial resolution. The design specifications of the trace instrument are presented.

  19. On the hadron mass decomposition

    Science.gov (United States)

    Lorcé, Cédric

    2018-02-01

    We argue that the standard decompositions of the hadron mass overlook pressure effects, and hence should be interpreted with great care. Based on the semiclassical picture, we propose a new decomposition that properly accounts for these pressure effects. Because of Lorentz covariance, we stress that the hadron mass decomposition automatically comes along with a stability constraint, which we discuss for the first time. We show also that if a hadron is seen as made of quarks and gluons, one cannot decompose its mass into more than two contributions without running into trouble with the consistency of the physical interpretation. In particular, the so-called quark mass and trace anomaly contributions appear to be purely conventional. Based on the current phenomenological values, we find that in average quarks exert a repulsive force inside nucleons, balanced exactly by the gluon attractive force.

  20. On the hadron mass decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Lorce, Cedric [Universite Paris-Saclay, Centre de Physique Theorique, Ecole Polytechnique, CNRS, Palaiseau (France)

    2018-02-15

    We argue that the standard decompositions of the hadron mass overlook pressure effects, and hence should be interpreted with great care. Based on the semiclassical picture, we propose a new decomposition that properly accounts for these pressure effects. Because of Lorentz covariance, we stress that the hadron mass decomposition automatically comes along with a stability constraint, which we discuss for the first time. We show also that if a hadron is seen as made of quarks and gluons, one cannot decompose its mass into more than two contributions without running into trouble with the consistency of the physical interpretation. In particular, the so-called quark mass and trace anomaly contributions appear to be purely conventional. Based on the current phenomenological values, we find that in average quarks exert a repulsive force inside nucleons, balanced exactly by the gluon attractive force. (orig.)

  1. Modeling of contact tracing in social networks

    Science.gov (United States)

    Tsimring, Lev S.; Huerta, Ramón

    2003-07-01

    Spreading of certain infections in complex networks is effectively suppressed by using intelligent strategies for epidemic control. One such standard epidemiological strategy consists in tracing contacts of infected individuals. In this paper, we use a recently introduced generalization of the standard susceptible-infectious-removed stochastic model for epidemics in sparse random networks which incorporates an additional (traced) state. We describe a deterministic mean-field description which yields quantitative agreement with stochastic simulations on random graphs. We also discuss the role of contact tracing in epidemics control in small-world and scale-free networks. Effectiveness of contact tracing grows as the rewiring probability is reduced.

  2. RAY TRACING IMPLEMENTATION IN JAVA PROGRAMMING LANGUAGE

    Directory of Open Access Journals (Sweden)

    Aybars UĞUR

    2002-01-01

    Full Text Available In this paper realism in computer graphics and components providing realism are discussed at first. It is mentioned about illumination models, surface rendering methods and light sources for this aim. After that, ray tracing which is a technique for creating two dimensional image of a three-dimensional virtual environment is explained briefly. A simple ray tracing algorithm was given. "SahneIzle" which is a ray tracing program implemented in Java programming language which can be used on the internet is introduced. As a result, importance of network-centric ray tracing software is discussed.

  3. In vivo tracing of organophosphorus pesticides in cabbage (Brassica parachinensis) and aloe (Barbadensis)

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Junlang; Chen, Guosheng; Zhou, Hong; Xu, Jianqiao; Wang, Fuxin; Zhu, Fang, E-mail: ceszf@mail.sysu.edu.cn; Ouyang, Gangfeng, E-mail: cesoygf@mail.sysu.edu.cn

    2016-04-15

    In vivo solid-phase microextraction (SPME) sampling method coupled with gas chromatography–mass spectrometry (GC–MS) analysis was employed to trace the uptake and elimination of organophosphorus pesticides (OPPs) in two kinds of edible plants, cabbage (Brassica parachinensis) and aloe (Barbadensis). The metabolism of fenthion in aloe was also investigated by the liquid chromatography tandem mass spectrometry analysis (LC–MS/MS) to understand the fate of OPPs in living plants better. Transpiration stream concentration factor (TSCF) and depuration rate constants of the OPPs in living plants were obtained therein. The health risk of the OPPs treated aloe was estimated by the maximum residue limit (MRL) approach, and it revealed that the OPPs were rather safe for their fast degradable property. However, peak concentration of fenthion-sulfoxide was found to exceed the MRL and was higher than that of the parent fenthion, which indicated the potential risk of pesticide metabolites. This study highlighted the application of in vivo SPME for contaminant tracing in different living edible plants. The in vivo tracing method is very convenient and can provide more data to evaluate the risk of different pesticides, which are very important for the safety of agriculture production. - Highlights: • In vivo SPME was employed to sample organophosphorus pesticides in vegetables. • Uptake and elimination of OPPs were traced in cabbage and aloe. • In vivo tracing of fenthion demonstrated its metabolites could be rather dangerous. • The risks of OPPs were assessed based on the in vivo tracing data.

  4. In vivo tracing of organophosphorus pesticides in cabbage (Brassica parachinensis) and aloe (Barbadensis)

    International Nuclear Information System (INIS)

    Qiu, Junlang; Chen, Guosheng; Zhou, Hong; Xu, Jianqiao; Wang, Fuxin; Zhu, Fang; Ouyang, Gangfeng

    2016-01-01

    In vivo solid-phase microextraction (SPME) sampling method coupled with gas chromatography–mass spectrometry (GC–MS) analysis was employed to trace the uptake and elimination of organophosphorus pesticides (OPPs) in two kinds of edible plants, cabbage (Brassica parachinensis) and aloe (Barbadensis). The metabolism of fenthion in aloe was also investigated by the liquid chromatography tandem mass spectrometry analysis (LC–MS/MS) to understand the fate of OPPs in living plants better. Transpiration stream concentration factor (TSCF) and depuration rate constants of the OPPs in living plants were obtained therein. The health risk of the OPPs treated aloe was estimated by the maximum residue limit (MRL) approach, and it revealed that the OPPs were rather safe for their fast degradable property. However, peak concentration of fenthion-sulfoxide was found to exceed the MRL and was higher than that of the parent fenthion, which indicated the potential risk of pesticide metabolites. This study highlighted the application of in vivo SPME for contaminant tracing in different living edible plants. The in vivo tracing method is very convenient and can provide more data to evaluate the risk of different pesticides, which are very important for the safety of agriculture production. - Highlights: • In vivo SPME was employed to sample organophosphorus pesticides in vegetables. • Uptake and elimination of OPPs were traced in cabbage and aloe. • In vivo tracing of fenthion demonstrated its metabolites could be rather dangerous. • The risks of OPPs were assessed based on the in vivo tracing data.

  5. Zinc: a multipurpose trace element

    Energy Technology Data Exchange (ETDEWEB)

    Stefanidou, M.; Maravelias, C.; Dona, A.; Spiliopoulou, C. [University of Athens, Department of Forensic Medicine and Toxicology, Athens (Greece)

    2006-01-01

    Zinc (Zn) is one of the most important trace elements in the body and it is essential as a catalytic, structural and regulatory ion. It is involved in homeostasis, in immune responses, in oxidative stress, in apoptosis and in ageing. Zinc-binding proteins (metallothioneins, MTs), are protective in situations of stress and in situations of exposure to toxic metals, infections and low Zn nutrition. Metallothioneins play a key role in Zn-related cell homeostasis due to their high affinity for Zn, which is in turn relevant against oxidative stress and immune responses, including natural killer (NK) cell activity and ageing, since NK activity and Zn ion bioavailability decrease in ageing. Physiological supplementation of Zn in ageing and in age-related degenerative diseases corrects immune defects, reduces infection relapse and prevents ageing. Zinc is not stored in the body and excess intakes result in reduced absorption and increased excretion. Nevertheless, there are cases of acute and chronic Zn poisoning. (orig.)

  6. Full autonomous microline trace robot

    Science.gov (United States)

    Yi, Deer; Lu, Si; Yan, Yingbai; Jin, Guofan

    2000-10-01

    Optoelectric inspection may find applications in robotic system. In micro robotic system, smaller optoelectric inspection system is preferred. However, as miniaturizing the size of the robot, the number of the optoelectric detector becomes lack. And lack of the information makes the micro robot difficult to acquire its status. In our lab, a micro line trace robot has been designed, which autonomous acts based on its optoelectric detection. It has been programmed to follow a black line printed on the white colored ground. Besides the optoelectric inspection, logical algorithm in the microprocessor is also important. In this paper, we propose a simply logical algorithm to realize robot's intelligence. The robot's intelligence is based on a AT89C2051 microcontroller which controls its movement. The technical details of the micro robot are as follow: dimension: 30mm*25mm*35*mm; velocity: 60mm/s.

  7. Serum Concentrations of Trace Elements in Patients with Tuberculosis and Its Association with Treatment Outcome

    Directory of Open Access Journals (Sweden)

    Rihwa Choi

    2015-07-01

    Full Text Available Deficiencies in essential trace elements are associated with impaired immunity in tuberculosis infection. However, the trace element concentrations in the serum of Korean patients with tuberculosis have not yet been investigated. This study aimed to compare the serum trace element concentrations of Korean adult patients with tuberculosis with noninfected controls and to assess the impact of serum trace element concentration on clinical outcome after antituberculosis treatment. The serum concentrations of four trace elements in 141 consecutively recruited patients with tuberculosis and 79 controls were analyzed by inductively coupled plasma-mass spectrometry. Demographic characteristics were also analyzed. Serum cobalt and copper concentrations were significantly higher in patients with tuberculosis compared with controls, while zinc and selenium concentrations were significantly lower (p < 0.01. Moreover, serum selenium and zinc concentrations were positively correlated (ρ = 0.41, p < 0.05. A high serum copper concentration was associated with a worse clinical outcome, as assessed after one month of antituberculosis therapy. Specifically, culture-positive patients had higher serum copper concentrations than culture-negative patients (p < 0.05. Patients with tuberculosis had altered serum trace element concentrations. Further research is needed to elucidate the roles of individual trace elements and to determine their clinical impact on patients with tuberculosis.

  8. NEUTRINO MASS

    OpenAIRE

    Kayser, Boris

    1988-01-01

    This is a review article about the most recent developments on the field of neutrino mass. The first part of the review introduces the idea of neutrino masses and mixing angles, summarizes the most recent experimental data then discusses the experimental prospects and challenges in this area. The second part of the review discusses the implications of these results for particle physics and cosmology, including the origin of neutrino mass, the see-saw mechanism and sequential dominance, and la...

  9. Neutrino mass

    International Nuclear Information System (INIS)

    Robertson, R.G.H.

    1992-01-01

    Despite intensive experimental work since the neutrino's existence was proposed by Pauli 60 years ago, and its first observation by Reines and Cowan almost 40 years ago, the neutrino's fundamental properties remain elusive. Among those properties are the masses of the three known flavors, properties under charge conjugation, parity and time-reversal, and static and dynamic electromagnetic moments. Mass is perhaps the most fundamental, as it constrains the other properties. The present status of the search for neutrino mass is briefly reviewed

  10. Influence of trace aromatics on the chemical growth mechanisms of Titan aerosol analogues

    Science.gov (United States)

    Gautier, Thomas; Sebree, Joshua A.; Li, Xiang; Pinnick, Veronica T.; Grubisic, Andrej; Loeffler, Mark J.; Getty, Stephanie A.; Trainer, Melissa G.; Brinckerhoff, William B.

    2017-06-01

    The chemical structure and formation pathways of Titan aerosols remain largely unknown. In this work, we studied the effect of trace aromatics on the chemical composition and formation pathways of laboratory analogues of Titan's organic aerosols. The aerosol analogues were produced using four different trace aromatic molecules, comprised of one or two aromatic rings, each with or without a nitrogen heteroatom. Samples were then analyzed by laser desorption/ionization Mass Spectrometry (LDMS), revealing a high variability in the sample composition depending on the trace aromatic used. Our work reveals that the final chemical structure of the aerosols depends strongly on the number of aromatic rings in the trace molecule, leading either to a polymeric or to a random co-polymeric growth of the sample. These different chemical structures can affect the physical properties of the aerosol. Future analysis of Titan's aerosols using better resolution could potentially determine whether either of the growth hypotheses are preferred.

  11. Chronocoulometric determination of trace levels of uranium in rocks

    International Nuclear Information System (INIS)

    Cantagallo, M.I.C.; Gutz, I.G.R.

    1990-01-01

    The chronocoulometric method for the determination of trace levels of uranium, based on the catalytic nitrate reduction was applied with real and synthetic samples. Reference materials with complex matrices like rocks were first solubilized by hot digestion under pressure in a PTFE bomb. When necessary, an adapted liquid-liquid extraction procedure was used for previous separation of interferents. The obtained results are in good agreement with the values obtained with other techniques such as X-ray fluorescence, mass spectrometry -isotope dilution and apithermal activation analysis. (author) [pt

  12. Mass Spectrometry in the Home and Garden

    Science.gov (United States)

    Pulliam, Christopher J.; Bain, Ryan M.; Wiley, Joshua S.; Ouyang, Zheng; Cooks, R. Graham

    2015-02-01

    Identification of active components in a variety of chemical products used directly by consumers is described at both trace and bulk levels using mass spectrometry. The combination of external ambient ionization with a portable mass spectrometer capable of tandem mass spectrometry provides high chemical specificity and sensitivity as well as allowing on-site monitoring. These experiments were done using a custom-built portable ion trap mass spectrometer in combination with the ambient ionization methods of paper spray, leaf spray, and low temperature plasma ionization. Bactericides, garden chemicals, air fresheners, and other products were examined. Herbicide applied to suburban lawns was detected in situ on single leaves 5 d after application.

  13. Trace element metabolism in man and animals

    International Nuclear Information System (INIS)

    Kirchgessner, M.

    1977-01-01

    Uptake, distribution, storage, excretion of different trace elements and resulting disturbances are investigated in blood and organs in animal experiments and in human diagnostics with the aid of radioisotopes. Apart from this, untritional disturbances are mentioned. Finally, future aspects of physiological trace element examinations are listed. (AJ) 891 AJ [de

  14. Trace element analysis of soy sauce

    International Nuclear Information System (INIS)

    Tomita, Michio; Haruyama, Yoichi; Saito, Manabu

    1994-01-01

    Trace elements in soy sauce have been measured by means of in-air PIXE. Six kinds of trace elements were detected, such as Mu, Fe, Ni, Zn, Cu and Br. Concentrations of Mn, Fe, Zn and Br which were observed in all samples, have been determined. Each analyzed sample contained considerable amount of bromine about 160 ppm. (author)

  15. Entities of interest : Discovery in digital traces

    NARCIS (Netherlands)

    Graus, D.P.

    2017-01-01

    In the era of big data, we continuously — and at times unknowingly — leave behind digital traces, by browsing, sharing, posting, liking, searching, watching, and listening to online content. Aggregated, these digital traces can provide powerful insights into the behavior, preferences, activities,

  16. Reverse ray tracing for transformation optics.

    Science.gov (United States)

    Hu, Chia-Yu; Lin, Chun-Hung

    2015-06-29

    Ray tracing is an important technique for predicting optical system performance. In the field of transformation optics, the Hamiltonian equations of motion for ray tracing are well known. The numerical solutions to the Hamiltonian equations of motion are affected by the complexities of the inhomogeneous and anisotropic indices of the optical device. Based on our knowledge, no previous work has been conducted on ray tracing for transformation optics with extreme inhomogeneity and anisotropicity. In this study, we present the use of 3D reverse ray tracing in transformation optics. The reverse ray tracing is derived from Fermat's principle based on a sweeping method instead of finding the full solution to ordinary differential equations. The sweeping method is employed to obtain the eikonal function. The wave vectors are then obtained from the gradient of that eikonal function map in the transformed space to acquire the illuminance. Because only the rays in the points of interest have to be traced, the reverse ray tracing provides an efficient approach to investigate the illuminance of a system. This approach is useful in any form of transformation optics where the material property tensor is a symmetric positive definite matrix. The performance and analysis of three transformation optics with inhomogeneous and anisotropic indices are explored. The ray trajectories and illuminances in these demonstration cases are successfully solved by the proposed reverse ray tracing method.

  17. Trace maps for arbitrary substitution sequences

    International Nuclear Information System (INIS)

    Avishai, Y.

    1993-01-01

    The discovery of quasi-crystals and their 1-dimensional modeling have led to a deep mathematical study of Schroedinger operators with an arbitrary deterministic potential sequence. In this work we address this problem and find trace maps for an arbitrary substitution sequence. our trace maps have lower dimensionality than those of Kolar and Nori, which make them quite attractive for actual applications. (authors)

  18. NSF-RANN trace contaminants abstracts

    International Nuclear Information System (INIS)

    Copenhaver, E.D.; Harnden, D.S.

    1976-10-01

    Specific areas of interest of the Environmental Aspects of Trace Contaminants Program are organic chemicals of commerce, metals and organometallic compounds, air-borne contaminants, and environmental assay methodology. Fifty-three abstracts of literature on trace contaminants are presented. Author, keyword, and permuted title indexes are included

  19. Trace elements as paradigms of developmental neurotoxicants

    DEFF Research Database (Denmark)

    Grandjean, Philippe; Herz, Katherine T

    2015-01-01

    Trace elements have contributed unique insights into developmental neurotoxicity and serve as paradigms for such adverse effects. Many trace elements are retained in the body for long periods and can be easily measured to assess exposure by inexpensive analytical methods that became available...

  20. Ray Tracing for Real-time Games

    NARCIS (Netherlands)

    Bikker, J.

    2012-01-01

    This thesis describes efficient rendering algorithms based on ray tracing, and the application of these algorithms to real-time games. Compared to rasterizationbased approaches, rendering based on ray tracing allows elegant and correct simulation of important global effects, such as shadows,

  1. Monsoon signatures in trace gas records from Cape Rama, India

    International Nuclear Information System (INIS)

    Bhattacharya, S.K.; Jani, R.A.; Borole, D.V.; Francey, R.J.; Allison, C.E.; Masarie, K.A.

    2002-01-01

    Concentrations of trace gases CO 2 , CH 4 , CO, N 2 O and H 2 , and the stable carbon and oxygen isotopic composition of CO 2 have been measured in air samples collected from Cape Rama, a coastal station on the west coast of India, since 1993. The data show clear signatures of continental and oceanic air mass resulting in complex seasonal variation of trace gas characteristics. The regional atmospheric circulation in the Indian Ocean and Arabian Sea undergoes biannual reversal in low-level winds associated with the yearly migration of the inter-tropical convergence zone (ITCZ). From June to September, the wind is from the equatorial Indian Ocean to the Indian subcontinent (southwest monsoon) and brings in pristine marine air. From December to February, dry continental winds blow from the northeast and transport continental emissions to the ocean (northeast monsoon). Detailed transport and chemical modelling will be necessary to interpret these records, however the potential to identify and constrain the regional trace gas emissions appears to be high. (author)

  2. Infrared photothermal imaging of trace explosives on relevant substrates

    Science.gov (United States)

    Kendziora, Christopher A.; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; Borchert, James; Byers, Jeff; McGill, R. Andrew

    2013-06-01

    We are developing a technique for the stand-off detection of trace explosives on relevant substrate surfaces using photo-thermal infrared (IR) imaging spectroscopy (PT-IRIS). This approach leverages one or more compact IR quantum cascade lasers, tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface and detect small increases in thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral and temporal dimensions as vectors within a detection algorithm. The ability to detect trace analytes on relevant substrates is critical for stand-off applications, but is complicated by the optical and thermal analyte/substrate interactions. This manuscript describes recent PT-IRIS experimental results and analysis for traces of RDX, TNT, ammonium nitrate (AN) and sucrose on relevant substrates (steel, polyethylene, glass and painted steel panels). We demonstrate that these analytes can be detected on these substrates at relevant surface mass loadings (10 μg/cm2 to 100 μg/cm2) even at the single pixel level.

  3. Protostellar accretion traced with chemistry

    DEFF Research Database (Denmark)

    Frimann, Søren; Jørgensen, Jes Kristian; Dunham, Michael M.

    2017-01-01

    . Our aim is to characterise protostellar accretion histories towards individual sources by utilising sublimation and freeze-out chemistry of CO. Methods. A sample of 24 embedded protostars are observed with the Submillimeter Array (SMA) in context of the large program "Mass Assembly of Stellar Systems...

  4. Digital Stratigraphy: Contextual Analysis of File System Traces in Forensic Science.

    Science.gov (United States)

    Casey, Eoghan

    2017-12-28

    This work introduces novel methods for conducting forensic analysis of file allocation traces, collectively called digital stratigraphy. These in-depth forensic analysis methods can provide insight into the origin, composition, distribution, and time frame of strata within storage media. Using case examples and empirical studies, this paper illuminates the successes, challenges, and limitations of digital stratigraphy. This study also shows how understanding file allocation methods can provide insight into concealment activities and how real-world computer usage can complicate digital stratigraphy. Furthermore, this work explains how forensic analysts have misinterpreted traces of normal file system behavior as indications of concealment activities. This work raises awareness of the value of taking the overall context into account when analyzing file system traces. This work calls for further research in this area and for forensic tools to provide necessary information for such contextual analysis, such as highlighting mass deletion, mass copying, and potential backdating. © 2017 American Academy of Forensic Sciences.

  5. Double-trace deformations of conformal correlations

    Science.gov (United States)

    Giombi, Simone; Kirilin, Vladimir; Perlmutter, Eric

    2018-02-01

    Large N conformal field theories often admit unitary renormalization group flows triggered by double-trace deformations. We compute the change in scalar four-point functions under double-trace flow, to leading order in 1/ N. This has a simple dual in AdS, where the flow is implemented by a change of boundary conditions, and provides a physical interpretation of single-valued conformal partial waves. We extract the change in the conformal dimensions and three-point coefficients of infinite families of double-trace composite operators. Some of these quantities are found to be sign-definite under double-trace flow. As an application, we derive anomalous dimensions of spinning double-trace operators comprised of non-singlet constituents in the O( N) vector model.

  6. Mass Society

    DEFF Research Database (Denmark)

    Borch, Christian

    2017-01-01

    the negative features usually ascribed by late nineteenth-century crowd psychology to spontaneous crowds, and attributes these to the entire social fabric. However, in contrast to crowd psychology, theorists of mass society often place greater emphasis on how capitalism, technological advances, or demographic......Mass society is a societal diagnosis that emphasizes – usually in a pejorative, modernity critical manner – a series of traits allegedly associated with modern society, such as the leveling of individuality, moral decay, alienation, and isolation. As such, the notion of mass society generalizes...... developments condition such negative features, and some theorists argue that mass society produces a propensity to totalitarianism. Discussions of mass society culminated in the early and mid-twentieth century....

  7. Autonomous Real Time Requirements Tracing

    Science.gov (United States)

    Plattsmier, George; Stetson, Howard

    2014-01-01

    One of the more challenging aspects of software development is the ability to verify and validate the functional software requirements dictated by the Software Requirements Specification (SRS) and the Software Detail Design (SDD). Insuring the software has achieved the intended requirements is the responsibility of the Software Quality team and the Software Test team. The utilization of Timeliner-TLX(sup TM) Auto- Procedures for relocating ground operations positions to ISS automated on-board operations has begun the transition that would be required for manned deep space missions with minimal crew requirements. This transition also moves the auto-procedures from the procedure realm into the flight software arena and as such the operational requirements and testing will be more structured and rigorous. The autoprocedures would be required to meet NASA software standards as specified in the Software Safety Standard (NASASTD- 8719), the Software Engineering Requirements (NPR 7150), the Software Assurance Standard (NASA-STD-8739) and also the Human Rating Requirements (NPR-8705). The Autonomous Fluid Transfer System (AFTS) test-bed utilizes the Timeliner-TLX(sup TM) Language for development of autonomous command and control software. The Timeliner-TLX(sup TM) system has the unique feature of providing the current line of the statement in execution during real-time execution of the software. The feature of execution line number internal reporting unlocks the capability of monitoring the execution autonomously by use of a companion Timeliner-TLX(sup TM) sequence as the line number reporting is embedded inside the Timeliner-TLX(sup TM) execution engine. This negates I/O processing of this type data as the line number status of executing sequences is built-in as a function reference. This paper will outline the design and capabilities of the AFTS Autonomous Requirements Tracker, which traces and logs SRS requirements as they are being met during real-time execution of the

  8. Particle Tracing Modeling with SHIELDS

    Science.gov (United States)

    Woodroffe, J. R.; Brito, T. V.; Jordanova, V. K.

    2017-12-01

    The near-Earth inner magnetosphere, where most of the nation's civilian and military space assets operate, is an extremely hazardous region of the space environment which poses major risks to our space infrastructure. Failure of satellite subsystems or even total failure of a spacecraft can arise for a variety of reasons, some of which are related to the space environment: space weather events like single-event-upsets and deep dielectric charging caused by high energy particles, or surface charging caused by low to medium energy particles; other space hazards are collisions with natural or man-made space debris, or intentional hostile acts. A recently funded project through the Los Alamos National Laboratory (LANL) Directed Research and Development (LDRD) program aims at developing a new capability to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. The project goals are to understand the dynamics of the surface charging environment (SCE), the hot (keV) electrons on both macro- and microscale. These challenging problems are addressed using a team of world-class experts and state-of-the-art physics-based models and computational facilities. We present first results of a coupled BATS-R-US/RAM-SCB/Particle Tracing Model to evaluate particle fluxes in the inner magnetosphere. We demonstrate that this setup is capable of capturing the earthward particle acceleration process resulting from dipolarization events in the tail region of the magnetosphere.

  9. trace metals in selected fish species from lakes awassa and ziway

    African Journals Online (AJOL)

    Preferred Customer

    were collected from six sampling stations in Lakes Awassa and Ziway, Ethiopia. The edible ... Concentrations of trace elements in the fishes ranged (µg element/g dry mass): Zn. 23.04–30.92; Fe ...... water and soil sediments from some fishponds. Int. J. Environ. ... radioactive contaminants in the aquatic environ- ment and ...

  10. MESOLITHIC HUMAN BONES FROM THE UPPER VOLGA BASIN : RADIOCARBON AND TRACE ELEMENTS

    NARCIS (Netherlands)

    Alexandrovskiy, A. L.; Alexandrovskaya, E. I.; Zhilin, M. I.; van der Plicht, J.

    2009-01-01

    Human bones from 3 Mesolithic sites in the Upper Volga basin were analyzed for trace elements, and dated by accelerator mass spectrometry (AMS). The radiocarbon dates of the bones correspond to the Mesolithic era. However, some dates differ from those obtained for the enclosing deposits and for the

  11. Olivine Major and Trace Element Compositions in Southern Payenia Basalts, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Portnyagin, Maxim; Hoernle, Kaj

    2015-01-01

    Olivine major and trace element compositions from 12 basalts from the southern Payenia volcanic province in Argentina have been analyzed by electron microprobe and laser ablation inductively coupled plasma mass spectrometry. The olivines have high Fe/Mn and low Ca/Fe and many fall at the end of t...

  12. ISOFORMAL: isotopic tracing of formaldehyde sources in housing. Intermediary report

    International Nuclear Information System (INIS)

    2011-01-01

    The authors report an investigation which comprised a sampling and a chemical and isotopic analysis of emissions from the main indoor formaldehyde pollution sources in order to create a exhaustive database. Emissions which are characteristic of motorcar traffic, are also sampled in order to asses their possible contribution in the housing air. This step will be used to develop emission simulations of formaldehyde sources in a laboratory-house in order to validate the isotopic approach as tracing tool for sources of this compound. The report describes the carbon and hydrogen steady isotopes. It presents the sampling procedure, reports the determination of formaldehyde concentrations by high performance liquid chromatography with UV detectors, the use of gas source mass spectrometry, and the analytic development of the isotopic analysis of formaldehyde by gas chromatography combustion isotope ratio mass spectrometry. Outdoor and indoor pollution sources are discussed

  13. Australis: AMS for ultra sensitive trace element and isotopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Sie, S H; Suter, G F [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1994-12-31

    The accelerator mass spectrometer (AMS) at the CSIRO HIAF laboratory is being upgraded to enable in-situ measurements of ultratraces and isotopic-ratios in mineralogical applications. The upgraded system will include a microbeam Cs ion source which is designed to produce better than 50 micrometre diameter Cs beam to enable analyses of monomineralic grains. The Cs primary beam will be mass analysed in order to minimize contamination of the sample. The detection system will be upgraded to enable analyses of elements up to U, at 2 MV terminal voltage for charge states 4 and 5. The system will be known as AUSTRALIS: A.M.S. for Ultra Sensitive TRAce eLement and Isotopic Studies. An overview of the system and the anticipated applications in minerals exploration and mining research are presented. 4 refs., 1 fig.

  14. Australis: AMS for ultra sensitive trace element and isotopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Sie, S.H.; Suter, G.F. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1993-12-31

    The accelerator mass spectrometer (AMS) at the CSIRO HIAF laboratory is being upgraded to enable in-situ measurements of ultratraces and isotopic-ratios in mineralogical applications. The upgraded system will include a microbeam Cs ion source which is designed to produce better than 50 micrometre diameter Cs beam to enable analyses of monomineralic grains. The Cs primary beam will be mass analysed in order to minimize contamination of the sample. The detection system will be upgraded to enable analyses of elements up to U, at 2 MV terminal voltage for charge states 4 and 5. The system will be known as AUSTRALIS: A.M.S. for Ultra Sensitive TRAce eLement and Isotopic Studies. An overview of the system and the anticipated applications in minerals exploration and mining research are presented. 4 refs., 1 fig.

  15. Australis: AMS for ultra sensitive trace element and isotopic studies

    International Nuclear Information System (INIS)

    Sie, S.H.; Suter, G.F.

    1993-01-01

    The accelerator mass spectrometer (AMS) at the CSIRO HIAF laboratory is being upgraded to enable in-situ measurements of ultratraces and isotopic-ratios in mineralogical applications. The upgraded system will include a microbeam Cs ion source which is designed to produce better than 50 micrometre diameter Cs beam to enable analyses of monomineralic grains. The Cs primary beam will be mass analysed in order to minimize contamination of the sample. The detection system will be upgraded to enable analyses of elements up to U, at 2 MV terminal voltage for charge states 4 and 5. The system will be known as AUSTRALIS: A.M.S. for Ultra Sensitive TRAce eLement and Isotopic Studies. An overview of the system and the anticipated applications in minerals exploration and mining research are presented. 4 refs., 1 fig

  16. Mass hysteria

    CERN Document Server

    Hellemans, Alexander

    2004-01-01

    Considerable research is being undertaken to identify the Higgs particle that is believed to give things their mass. According to the standard model, what we call mass is really an indication of how strongly particles interact with an invisible syrupy substance called the Higgs field. Quantum mechanics say that the mass-giving field can also be thought of as a sea of electrically neutral Higgs particles that should be dislodged in collisions between subatomic particles with high enough energies. Particle physicists expect the Higgs to exist only for a fleeting moment before decaying into other particles, which are caught in a detector. (Edited abstract).

  17. The trace anomaly and massless scalar degrees of freedom

    Energy Technology Data Exchange (ETDEWEB)

    Gianotti, Maurizio [Los Alamos National Laboratory; Mottola, Emil [Los Alamos National Laboratory

    2008-01-01

    The trace anomaly of quantum fields in electromagnetic or gravitational backgrounds implies the existence of massless scalar poles in physical amplitudes involving the stress-energy tensor. Considering first the axial anomaly and using QED as an example, we compute the full one-loop triangle amplitude of the fermionic stress tensor with two current vertices, {open_square}T{sup {mu}{nu}}J{sup {alpha}}J{sup {beta}}, and exhibit the scalar pole in this amplitude associated with the trace anomaly, in the limit of zero electron mass m{yields}0. To emphasize the infrared aspect of the anomaly, we use a dispersive approach and show that this amplitude and the existence of the massless scalar pole is determined completely by its ultraviolet finite terms, together with the requirements of Poincare invariance of the vacuum, Bose symmetry under interchange of J{sup {alpha}} and J{sup {beta}}, and vector current and stress-tensor conservation. We derive a sum rule for the appropriate positive spectral function corresponding to the discontinuity of the triangle amplitude, showing that it becomes proportional to {delta}(k{sup 2}) and therefore contains a massless scalar intermediate state in the conformal limit of zero electron mass. The effective action corresponding to the trace of the triangle amplitude can be expressed in local form by the introduction of two scalar auxiliary fields which satisfy massless wave equations. These massless scalar degrees of freedom couple to classical sources, contribute to gravitational scattering processes, and can have long range gravitational effects.

  18. From trace chemistry to single atom chemistry

    International Nuclear Information System (INIS)

    Adloff, J.P.

    1993-01-01

    Hot atom chemistry in the vast majority of experimental works deals with the trace amount of radioactive matters. Accordingly, the concept of trace chemistry is at the heart of hot atom chemistry. Some aspects of the chemistry at trace scale and at subtrace scale are presented together with the related problems of speciation and the complication which may arise due to the formation of radio colloids. The examples of 127 I(n,γ) 128 I and 132 Te (β - ) 132 I are shown, and the method based on radioactivity was used. The procedure of separating the elements in pitchblende is shown as the example of the chemistry of traces. 13 27 Al+ 2 4 He→ 0 1 n+ 15 30 P and 15 30 P→ 14 30 Si+e + +V are shown, and how to recognize the presence of radioactive colloids is explained. The formation of radiocolloids is by the sorption of a trace radioelement on pre-existing colloidal impurity or the self-condensation of monomeric species. The temporal parameters of the nature of reactions at trace concentration are listed. The examples of Class A and Class B reactions are shown. The kinetics of reactions at trace level, radon concentration, anthropogenic Pu and natural Pu in environment, the behavior of Pu atoms and so on are described. (K.I.)

  19. Discrimination of forensic trace evidence using laser induced breakdown spectroscopy

    Science.gov (United States)

    Bridge, Candice Mae

    Elemental analysis in forensic laboratories can be tedious and many trace evidence items are not analyzed to determine their elemental composition. Presently, scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS) is the primary analytical tool for determining the elemental composition of trace evidence items. However, due to the time it takes to obtain the required vacuum and the limited number of samples that can be analyzed at any one time, SEM-EDS can be impractical for a high volume of evidence items. An alternative instrument that can be used for this type of analysis is laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). While LA-ICP-MS is a very precise and quantitative analytical method that determines elemental composition based on isotopic mass measurements; however, the instrumentation is relatively expensive and therefore is budgetarily prohibitive for many forensic laboratories. It is the purpose of this research to evaluate an inexpensive instrument that can potentially provide rapid elemental analysis for many forensic laboratories. Laser induced breakdown spectroscopy (LIBS) is an analytical method that meets these requirements and offers information about the elemental composition based on ionic, atomic and diatomic molecular emissions.

  20. Spoken word recognition without a TRACE

    Science.gov (United States)

    Hannagan, Thomas; Magnuson, James S.; Grainger, Jonathan

    2013-01-01

    How do we map the rapid input of spoken language onto phonological and lexical representations over time? Attempts at psychologically-tractable computational models of spoken word recognition tend either to ignore time or to transform the temporal input into a spatial representation. TRACE, a connectionist model with broad and deep coverage of speech perception and spoken word recognition phenomena, takes the latter approach, using exclusively time-specific units at every level of representation. TRACE reduplicates featural, phonemic, and lexical inputs at every time step in a large memory trace, with rich interconnections (excitatory forward and backward connections between levels and inhibitory links within levels). As the length of the memory trace is increased, or as the phoneme and lexical inventory of the model is increased to a realistic size, this reduplication of time- (temporal position) specific units leads to a dramatic proliferation of units and connections, begging the question of whether a more efficient approach is possible. Our starting point is the observation that models of visual object recognition—including visual word recognition—have grappled with the problem of spatial invariance, and arrived at solutions other than a fully-reduplicative strategy like that of TRACE. This inspires a new model of spoken word recognition that combines time-specific phoneme representations similar to those in TRACE with higher-level representations based on string kernels: temporally independent (time invariant) diphone and lexical units. This reduces the number of necessary units and connections by several orders of magnitude relative to TRACE. Critically, we compare the new model to TRACE on a set of key phenomena, demonstrating that the new model inherits much of the behavior of TRACE and that the drastic computational savings do not come at the cost of explanatory power. PMID:24058349

  1. Mass spectrometry with accelerators.

    Science.gov (United States)

    Litherland, A E; Zhao, X-L; Kieser, W E

    2011-01-01

    As one in a series of articles on Canadian contributions to mass spectrometry, this review begins with an outline of the history of accelerator mass spectrometry (AMS), noting roles played by researchers at three Canadian AMS laboratories. After a description of the unique features of AMS, three examples, (14)C, (10)Be, and (129)I are given to illustrate the methods. The capabilities of mass spectrometry have been extended by the addition of atomic isobar selection, molecular isobar attenuation, further ion acceleration, followed by ion detection and ion identification at essentially zero dark current or ion flux. This has been accomplished by exploiting the techniques and accelerators of atomic and nuclear physics. In 1939, the first principles of AMS were established using a cyclotron. In 1977 the selection of isobars in the ion source was established when it was shown that the (14)N(-) ion was very unstable, or extremely difficult to create, making a tandem electrostatic accelerator highly suitable for assisting the mass spectrometric measurement of the rare long-lived radioactive isotope (14)C in the environment. This observation, together with the large attenuation of the molecular isobars (13)CH(-) and (12)CH 2(-) during tandem acceleration and the observed very low background contamination from the ion source, was found to facilitate the mass spectrometry of (14)C to at least a level of (14)C/C ~ 6 × 10(-16), the equivalent of a radiocarbon age of 60,000 years. Tandem Accelerator Mass Spectrometry, or AMS, has now made possible the accurate radiocarbon dating of milligram-sized carbon samples by ion counting as well as dating and tracing with many other long-lived radioactive isotopes such as (10)Be, (26)Al, (36)Cl, and (129)I. The difficulty of obtaining large anion currents with low electron affinities and the difficulties of isobar separation, especially for the heavier mass ions, has prompted the use of molecular anions and the search for alternative

  2. Trace element analysis: a diagnostic tool

    International Nuclear Information System (INIS)

    Qureshi, I.H.; Cheema, M.N.

    1976-09-01

    The human mody continuously assimilates a variety of elements from the environment, and the concentration of these elements in the blood is regulated by means of various homeostatic mechanisms. Some of the elements, though present in very small amounts, have highly specialized functions in initiating many biochemical reactions. These elements, known as essential trace elements, are closely related to human diseases since their deficiency or excess induces physiological changes. Many diseases such as hypertension, atherosclerosis, diabetes, etc., are related to an imbalance in trace element. The measurement of trace elements in body fluids and tissues can, therefore, be effectively employed for diagnostic tests

  3. Modulation of capillary condensation by trace component

    Directory of Open Access Journals (Sweden)

    Shiqi Zhou

    2011-06-01

    Full Text Available Impact of trace component on capillary condensation (CC is investigated systematically using a classical density functional theory. It is discovered that (i presence of the trace component makes the CC to occur at much lower condensation pressure than when its absence; (ii Lennard-Jones potential parameters like size parameter and energy parameter of the trace component, and its concentration in the bulk adsorption system, show their effects the most remarkably within a particular range beyond which the effects eventually become insignificant. The present discoveries have implications in low pressure storage of gases, separation and enrichment of low concentration component, and easy control of CC transition, etc.

  4. Remediation using trace element humate surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Riddle, Catherine Lynn; Taylor, Steven Cheney; Bruhn, Debra Fox

    2016-08-30

    A method of remediation at a remediation site having one or more undesirable conditions in which one or more soil characteristics, preferably soil pH and/or elemental concentrations, are measured at a remediation site. A trace element humate surfactant composition is prepared comprising a humate solution, element solution and at least one surfactant. The prepared trace element humate surfactant composition is then dispensed onto the remediation site whereby the trace element humate surfactant composition will reduce the amount of undesirable compounds by promoting growth of native species activity. By promoting native species activity, remediation occurs quickly and environmental impact is minimal.

  5. Using column experiments to examine transport of As and other trace elements released from poultry litter: Implications for trace element mobility in agricultural watersheds

    International Nuclear Information System (INIS)

    Oyewumi, Oluyinka; Schreiber, Madeline E.

    2017-01-01

    Trace elements are added to poultry feed to control infection and improve weight gain. However, the fate of these trace elements in poultry litter is poorly understood. Because poultry litter is applied as fertilizer in many agricultural regions, evaluation of the environmental processes that influence the mobility of litter-derived trace elements is critical for predicting if trace elements are retained in soil or released to water. This study examined the effect of dissolved organic carbon (DOC) in poultry litter leachate on the fate and transport of litter-derived elements (As, Cu, P and Zn) using laboratory column experiments with soil collected from the Delmarva Peninsula (Mid-Atlantic, USA), a region of intense poultry production. Results of the experiments showed that DOC enhanced the mobility of all of the studied elements. However, despite the increased mobility, 60–70% of Zn, As and P mass was retained within the soil. In contrast, almost all of the Cu was mobilized in the litter leachate experiments, with very little retention in soil. Overall, our results demonstrate that the mobility of As, Cu, Zn and P in soils which receive poultry litter application is strongly influenced by both litter leachate composition, specifically organic acids, and adsorption to soil. Results have implications for understanding fate and transport of trace elements released from litter application to soil water and groundwater, which can affect both human health and the environment. - Highlights: • Column experiments examined fate of trace elements derived from poultry litter leachate in soils from Delaware, USA. • Influent solutions included poultry litter leachate and simulated solution without DOC. • Results showed increased mobility of litter-derived As, Cu, Zn and P in solution in the presence of DOC. • Mass balance showed all of Cu mass remained in solution but most (60–70%) of the Zn, As and P mass was associated with soil. • Study results show that DOC

  6. Effect of ionic composition of meteor trace on its relaxation time in the presence of external electric field

    International Nuclear Information System (INIS)

    Klimov, M.P.; Lyatskaya, A.M.

    1989-01-01

    The dissipation of meteor trace as the function of ionic composition and electric field is investigated numerically. Critical values of electric field E 1 and E 2 are determined. At E 1 the dissipation process is similar to the diffusion one; lifetimes are proportional to diffusion coefficient. At E 1 2 - the dissipation process falls into two phases with different character of lifetime dependence on meteor trace mass. At E>E 2 lifetime does not depend on the electric field

  7. Geochemistry of environmentally sensitive trace elements in Permian coals from the Huainan coalfield, Anhui, China

    Science.gov (United States)

    Chen, J.; Liu, Gaisheng; Jiang, M.; Chou, C.-L.; Li, H.; Wu, B.; Zheng, Lingyun; Jiang, D.

    2011-01-01

    To study the geochemical characteristics of 11 environmentally sensitive trace elements in the coals of the Permian Period from the Huainan coalfield, Anhui province, China, borehole samples of 336 coals, two partings, and four roof and floor mudstones were collected from mineable coal seams. Major elements and selected trace elements were determined by inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), and hydride generation atomic absorption spectrometry (HAAS). The depositional environment, abundances, distribution, and modes of occurrence of trace elements were investigated. Results show that clay and carbonate minerals are the principal inorganic constituents in the coals. A lower deltaic plain, where fluvial channel systems developed successively, was the likely depositional environment of the Permian coals in the Huainan coalfield. All major elements have wider variation ranges than those of Chinese coals except for Mg and Fe. The contents of Cr, Co, Ni, and Se are higher than their averages for Chinese coals and world coals. Vertical variations of trace elements in different formations are not significant except for B and Ba. Certain roof and partings are distinctly higher in trace elements than underlying coal bench samples. The modes of occurrence of trace elements vary in different coal seams as a result of different coal-forming environments. Vanadium, Cr, and Th are associated with aluminosilicate minerals, Ba with carbonate minerals, and Cu, Zn, As, Se, and Pb mainly with sulfide minerals. ?? 2011 Elsevier B.V.

  8. Origin of CP-violation through quark mass matrix

    International Nuclear Information System (INIS)

    Kang, K.

    1990-01-01

    After a brief review of the CP violation models, we trace the origin of CP-phases from the phases of a class of quark mass matrices compatible with the calculability condition. The case of three generations corresponding to the standard milliweak CP model is discussed explicitly for the generic case of Fritzsch-type mass matrices. (orig.)

  9. Using column experiments to examine transport of As and other trace elements released from poultry litter: Implications for trace element mobility in agricultural watersheds.

    Science.gov (United States)

    Oyewumi, Oluyinka; Schreiber, Madeline E

    2017-08-01

    Trace elements are added to poultry feed to control infection and improve weight gain. However, the fate of these trace elements in poultry litter is poorly understood. Because poultry litter is applied as fertilizer in many agricultural regions, evaluation of the environmental processes that influence the mobility of litter-derived trace elements is critical for predicting if trace elements are retained in soil or released to water. This study examined the effect of dissolved organic carbon (DOC) in poultry litter leachate on the fate and transport of litter-derived elements (As, Cu, P and Zn) using laboratory column experiments with soil collected from the Delmarva Peninsula (Mid-Atlantic, USA), a region of intense poultry production. Results of the experiments showed that DOC enhanced the mobility of all of the studied elements. However, despite the increased mobility, 60-70% of Zn, As and P mass was retained within the soil. In contrast, almost all of the Cu was mobilized in the litter leachate experiments, with very little retention in soil. Overall, our results demonstrate that the mobility of As, Cu, Zn and P in soils which receive poultry litter application is strongly influenced by both litter leachate composition, specifically organic acids, and adsorption to soil. Results have implications for understanding fate and transport of trace elements released from litter application to soil water and groundwater, which can affect both human health and the environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Computer automation of an accelerator mass spectrometry system

    International Nuclear Information System (INIS)

    Gressett, J.D.; Maxson, D.L.; Matteson, S.; McDaniel, F.D.; Duggan, J.L.; Mackey, H.J.; North Texas State Univ., Denton, TX; Anthony, J.M.

    1989-01-01

    The determination of trace impurities in electronic materials using accelerator mass spectrometry (AMS) requires efficient automation of the beam transport and mass discrimination hardware. The ability to choose between a variety of charge states, isotopes and injected molecules is necessary to provide survey capabilities similar to that available on conventional mass spectrometers. This paper will discuss automation hardware and software for flexible, high-sensitivity trace analysis of electronic materials, e.g. Si, GaAs and HgCdTe. Details regarding settling times will be presented, along with proof-of-principle experimental data. Potential and present applications will also be discussed. (orig.)

  11. LA-ICP-MS for Trace Analysis of Long-Lived Radionuclides in Solid Non-conducting Radioactive Waste Samples

    International Nuclear Information System (INIS)

    Becker, J.S.; Gastel, M.; Tenzler, D.; Dietze, H.J.

    1999-01-01

    The characterization of radioactive waste materials from nuclear reactors for recycling and final storage requires fast, sensitive and precise analytical methods, which are able to determine long-lived radionuclidic ultra traces in a short time. For the determination of long-lived α and β ray-emitting nuclides besides the classical radiochemical methods which are mostly include time-consuming radiochemical separation procedures, to an increasing extent inductively coupled plasma mass spectrometry (ICP-MS) has been used successfully as a powerful trace, ultra trace and isotopic analytical method for the determination of long-lived radionuclides in aqueous solutions [1-3

  12. Real time ray tracing based on shader

    Science.gov (United States)

    Gui, JiangHeng; Li, Min

    2017-07-01

    Ray tracing is a rendering algorithm for generating an image through tracing lights into an image plane, it can simulate complicate optical phenomenon like refraction, depth of field and motion blur. Compared with rasterization, ray tracing can achieve more realistic rendering result, however with greater computational cost, simple scene rendering can consume tons of time. With the GPU's performance improvement and the advent of programmable rendering pipeline, complicated algorithm can also be implemented directly on shader. So, this paper proposes a new method that implement ray tracing directly on fragment shader, mainly include: surface intersection, importance sampling and progressive rendering. With the help of GPU's powerful throughput capability, it can implement real time rendering of simple scene.

  13. Energy efficient trace removal by extractive distillation

    NARCIS (Netherlands)

    Jongmans, M.T.G.

    2012-01-01

    Separation processes contribute for about 40–70 % to the total energy requirements of the chemical process industry. Especially when trace removal is required to manufacture high purity products, traditional separation technologies become extremely expensive and are not providing satisfying

  14. Pre-LBA TRACE-A Data

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains atmospheric chemistry and meteorological data from the NASA Transport and Atmospheric Chemistry near the Equator-Atlantic (TRACE-A) field...

  15. Trace element measurements with synchrotron radiation

    International Nuclear Information System (INIS)

    Hanson, A.L.; Kraner, H.W.; Jones, K.W.; Gordon, B.M.; Mills, R.E.

    1982-01-01

    Aspects of the application of synchrotron radiation to trace element determinations by x-ray fluorescence have been investigated using beams from the Cornell facility, CHESS. Fluoresced x rays were detected with a Si(Li) detector placed 4 cm from the target at 90 0 to the beam. Thick samples of NBS Standard Reference Materials were used to calibrate trace element sensitivity and estimate minimum detectable limits for this method

  16. Trace element analysis of nail polishes

    International Nuclear Information System (INIS)

    Misra, G.; Mittal, V.K.; Sahota, H.S.

    1999-01-01

    Instrumental neutron activation analysis (INAA) technique was used to measure the concentrations of various trace elements in nail polishes of popular Indian and foreign brands. The aim of the present experiment was to see whether trace elements could distinguish nail polishes of different Indian and foreign brands from forensic point of view. It was found that cesium can act as a marker to differentiate foreign and Indian brands. (author)

  17. Instantons and the trace anomaly condition

    International Nuclear Information System (INIS)

    Dowrick, N.; McDougall, N.A.

    1988-01-01

    In the past, it has been claimed that instanton dynamics evaluated using the dilute-gas-approximation with a cut-off do not satisfy the trace anomaly condition, and that inter-instanton interactions were required to correct this. However, they show that any model for instanton dynamics automatically satisfies the trace anomlay condition provided no dimensionful parameter other than the QCD scale Λ is introduced during the calculation, and they explain the origin of the previous (incorrect) conclusion

  18. Trace element contamination in feather and tissue samples from Anna’s hummingbirds

    Science.gov (United States)

    Mikoni, Nicole A.; Poppenga, Robert H.; Ackerman, Joshua T.; Foley, Janet E.; Hazlehurst, Jenny; Purdin, Güthrum; Aston, Linda; Hargrave, Sabine; Jelks, Karen; Tell, Lisa A.

    2017-01-01

    Trace element contamination (17 elements; Be, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Ba, Hg, Tl, and Pb) of live (feather samples only) and deceased (feather and tissue samples) Anna's hummingbirds (Calypte anna) was evaluated. Samples were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS; 17 elements) and atomic absorption spectrophotometry (Hg only). Mean plus one standard deviation (SD) was considered the benchmark, and concentrations above the mean + 1 SD were considered elevated above normal. Contour feathers were sampled from live birds of varying age, sex, and California locations. In order to reduce thermal impacts, minimal feathers were taken from live birds, therefore a novel method was developed for preparation of low mass feather samples for ICP-MS analysis. The study found that the novel feather preparation method enabled small mass feather samples to be analyzed for trace elements using ICP-MS. For feather samples from live birds, all trace elements, with the exception of beryllium, had concentrations above the mean + 1 SD. Important risk factors for elevated trace element concentrations in feathers of live birds were age for iron, zinc, and arsenic, and location for iron, manganese, zinc, and selenium. For samples from deceased birds, ICP-MS results from body and tail feathers were correlated for Fe, Zn, and Pb, and feather concentrations were correlated with renal (Fe, Zn, Pb) or hepatic (Hg) tissue concentrations. Results for AA spectrophotometry analyzed samples from deceased birds further supported the ICP-MS findings where a strong correlation between mercury concentrations in feather and tissue (pectoral muscle) samples was found. These study results support that sampling feathers from live free-ranging hummingbirds might be a useful, non-lethal sampling method for evaluating trace element exposure and provides a sampling alternative since their small body size limits traditional sampling of blood and tissues. The

  19. Heavy metals and related trace elements

    International Nuclear Information System (INIS)

    Leland, H.V.; Luoma, S.N.; Wilkes, D.J.

    1977-01-01

    A review is given of heavy metals and related trace elements in the aquatic environment. Other reviews and bibliographies are cited, dealing with the metabolism and transport of metal ions and with the toxic effects of stable and radioactive trace metals on aquatic organisms. The sources of trace elements in natural waters are discussed. It is suggested that atmospheric inputs of several trace metals comprise sizable fractions of total inputs to the Great Lakes and continental shelf waters. Information on stack emissions of trace elements from a coal-fired steam plant was used to estimate the likely range of air concentrations and inputs to a forested watershed in Tennessee. Some basic concepts of cycling of elements through aquatic communities were examined, such as the Pb, Mn and Zn concentrations in sediment and estuarine plants and animals colonizing dredge-spoil disposal areas. The use of plants as biological indicators of trace element contamination was outlined, as well as bioaccumulation in aquatic fauna. The effects of environmental factors on the kinetics of element exchange were noted, for example the influx rates of Cs 137 in tubificid worms, and Co 60 and Zn 65 in shrimp were shown to be temperature dependent. The toxicity of heavy metals on aquatic fauna was discussed, such as the histopathological lesions in the kidney and liver of fishes caused by heavy metals, and the effects of Hg and Cu on the olfactory response of rainbow trout

  20. Trace Elements in Human Tooth Enamel

    Energy Technology Data Exchange (ETDEWEB)

    Nixon, G. S. [Turner Dental School, University Of Manchester, Manchester (United Kingdom); Smith, H.; Livingston, H. D. [Department of Forensic Medicine, University Of Glasgow, Glasgow (United Kingdom)

    1967-10-15

    The trace elements are considered to play a role in the resistance of teeth to dental caries. The exact mechanism by which they act has not yet been fully established. Estimations of trace elements have been undertaken in sound human teeth. By means of activation analysis it has been possible to determine trace element concentrations in different layers of enamel in the same tooth. The concentrations of the following elements have been determined: arsenic, antimony, copper, zinc, manganese, mercury, molybdenum and vanadium. The distribution of trace elements in enamel varies from those with a narrow range, such as manganese, to those with a broad range, such as antimony. The elements present in the broad range are considered to be non-essential and their presence is thought to result from a chance incorporation into the enamel. Those in the narrow range appear to be essential trace elements and are present in amounts which do not vary unduly from other body tissues. Only manganese and zinc were found in higher concentrations in the surface layer of enamel compared with the inner layers. The importance of the concentration of trace elements on this surface layer of enamel is emphasized as this layer is the site of the first attack by the carious process. (author)

  1. Screening for trace explosives by AccuTOF™-DART®: an in-depth validation study.

    Science.gov (United States)

    Sisco, Edward; Dake, Jeffrey; Bridge, Candice

    2013-10-10

    Ambient ionization mass spectrometry is finding increasing utility as a rapid analysis technique in a number of fields. In forensic science specifically, analysis of many types of samples, including drugs, explosives, inks, bank dye, and lotions, has been shown to be possible using these techniques [1]. This paper focuses on one type of ambient ionization mass spectrometry, Direct Analysis in Real Time Mass Spectrometry (DART-MS or DART), and its viability as a screening tool for trace explosives analysis. In order to assess viability, a validation study was completed which focused on the analysis of trace amounts of nitro and peroxide based explosives. Topics which were studied, and are discussed, include method optimization, reproducibility, sensitivity, development of a search library, discrimination of mixtures, and blind sampling. Advantages and disadvantages of this technique over other similar screening techniques are also discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  2. Numerical predictions of the separation of heavy components inside the trace gas concentrator

    International Nuclear Information System (INIS)

    Mo, J.D.

    1995-01-01

    The component with a heavier molecular weight can be separated from the one with a lighter molecular weight in a binary mixture by applying an appropriate pressure gradient. A centrifugal force field effectively generates the required pressure gradient and a favorable flow field along the radial direction in a trace gas concentrator for such an application. This paper presents the numerical predictions of the mass separation inside a trace gas concentrator, which enriches Xenon in air. A Navier-Stokes solver in primitive variables using a pressure based algorithm has been applied to solve for the flow fields. Subsequently, the transport equations with a strong centrifugal field are solved for the mass concentration. This study is the continued effort for the proof-of-concept of centrifugal separation of components with a considerable difference in their molecular weight in a binary mixture. The significant effects of rotational speed, flow field, and the geometrical configuration on the mass separation are presented in this paper

  3. Trace metallic elements in Helix aspersa terrestrial snails of a semiarid ecosystem

    International Nuclear Information System (INIS)

    Gaso P, M.I.; Segovia, N.; Zarazua, G.; Montes, F.; Morton, O.; Armienta, M.A.; Hernandez, E.

    2001-01-01

    The concentration of some major elements and traces in soil samples and of Helix aspersa eatable terrestrial snails were analysed at the Radioactive Wastes Storage Center (CADER) and in other reference sites. The methodology includes the use of an atomic absorption spectrophotometer, an X-ray fluorescence equipment and an Icp-mass spectroscope. The concentrations of some toxic elements (Ba, Cd, Cr, Ni, Pb and V) in the soft tissue of the snails were greater than the toxic levels reported in the literature for such trace elements. The snails compared with another wild eatable foods present transfer coefficients soil-snail high relatively. (Author)

  4. Analysis of Hair Trace Elements in Children with Autism Spectrum Disorders and Communication Disorders.

    Science.gov (United States)

    Skalny, Anatoly V; Simashkova, Natalia V; Klyushnik, Tatiana P; Grabeklis, Andrei R; Radysh, Ivan V; Skalnaya, Margarita G; Tinkov, Alexey A

    2017-06-01

    The primary objective of the present study is analysis of hair trace elements content in children with communication disorder (CD) and autism spectrum disorder (ASD). A total of 99 children from control, CD, and ASD groups (n = 33) were examined. All children were additionally divided into two subgroups according to age. Hair levels of trace elements were assessed using inductively coupled plasma mass spectrometry. The difference was considered significant at p elements including the toxic ones, it can be proposed that children suffering from ASD are characterized by more profound alteration of metal handling and excretion in comparison to CD.

  5. Neutrino mass?

    International Nuclear Information System (INIS)

    Kayser, B.

    1992-01-01

    After arguing that we should be looking for evidence of neutrino mass, we illustrate the possible consequences of neutrino mass and mixing. We then turn to the question of whether neutrinos are their own antiparticles, and to the process which may answer this question: neutrinoless double beta decay. Next, we review the proposed Mikheyev-Smirnov-Wolfenstein solution to the solar neutrino problem, and discuss models which can generate neutrino electromagnetic moments large enough to play a role in the sun. Finally, we consider how the possible 17 keV neutrino, if real, would fit in with everything we know about neutrinos. (orig.)

  6. Mass metrology

    CERN Document Server

    Gupta, S V

    2012-01-01

    This book presents the practical aspects of mass measurements. Concepts of gravitational, inertial and conventional mass and details of the variation of acceleration of gravity are described. The Metric Convention and International Prototype Kilogram and BIPM standards are described. The effect of change of gravity on the indication of electronic balances is derived with respect of latitude, altitude and earth topography. The classification of weights by OIML is discussed. Maximum permissible errors in different categories of weights prescribed by national and international organizations are p

  7. Foundations for Survivable System Development: Service Traces, Intrusion Traces, and Evaluation Models

    National Research Council Canada - National Science Library

    Linger, Richard

    2001-01-01

    .... On the system side, survivability specifications can be defined by essential-service traces that map essential-service workflows, derived from user requirements, into system component dependencies...

  8. Trace Element Analysis of Selenium

    International Nuclear Information System (INIS)

    Soliman, M.S.A.

    2010-01-01

    The present thesis divided into four chapters as follows:Chapter (1):This chapter contains an introduction on different oxidation states of organic and inorganic species for selenium in environmental and biological samples, the process for separation of selenium from these samples and the importance of selenium as a component for these samples. Also gives notes about the techniques which are used in the elemental analysis for selenium species and the detection limits for selenium in these techniques, selenium species in human body and the importance of these species in protecting the body from the different types of cancer and the sources of selenium in environmental samples (soil and water) and distribution levels of selenium in these samples.Chapter (2):This chapter is divided into two parts :The first part deals with the sample collection process for environmental samples (underground water, soil) and the wet digestion ( microwave digestion ) process of soil samples. It also contains the theory of work of the closed microwave digestion system.The second part contains detailed information concerning the theoretical considerations of the used analytical techniques. These techniques include Hydride generation - Atomic Absorption Spectrometer (HG-AAS), Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and Neutron Activation Analysis (NAA).Chapter (3): This chapter includes the methods of sampling, sample preparation, and sample digesition. The measures of quality assurance are disscused in this chapter. It describes in details the closed microwave digestion technique and the analytical methods used in this study which are present in Central Laboratory for Elemental and Isotopic Analysis (CLEIA) and the Egypt Second Research Reactor (ETRR-2). The described techniques are Atomic Absorption Spectrometer (AAS 6 vario, Analytical Jena GmbH, Germany), JMS-PLASMAX2 Mass Spectrometer (ICP-MS) and the Egypt Second Research Reactor (NAA).

  9. Mass spectrometry

    DEFF Research Database (Denmark)

    Nyvang Hartmeyer, Gitte; Jensen, Anne Kvistholm; Böcher, Sidsel

    2010-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently being introduced for the rapid and accurate identification of bacteria. We describe 2 MALDI-TOF MS identification cases - 1 directly on spinal fluid and 1 on grown bacteria. Rapidly obtained...

  10. Temporally rendered automatic cloud extraction (TRACE) system

    Science.gov (United States)

    Bodrero, Dennis M.; Yale, James G.; Davis, Roger E.; Rollins, John M.

    1999-10-01

    Smoke/obscurant testing requires that 2D cloud extent be extracted from visible and thermal imagery. These data are used alone or in combination with 2D data from other aspects to make 3D calculations of cloud properties, including dimensions, volume, centroid, travel, and uniformity. Determining cloud extent from imagery has historically been a time-consuming manual process. To reduce time and cost associated with smoke/obscurant data processing, automated methods to extract cloud extent from imagery were investigated. The TRACE system described in this paper was developed and implemented at U.S. Army Dugway Proving Ground, UT by the Science and Technology Corporation--Acuity Imaging Incorporated team with Small Business Innovation Research funding. TRACE uses dynamic background subtraction and 3D fast Fourier transform as primary methods to discriminate the smoke/obscurant cloud from the background. TRACE has been designed to run on a PC-based platform using Windows. The PC-Windows environment was chosen for portability, to give TRACE the maximum flexibility in terms of its interaction with peripheral hardware devices such as video capture boards, removable media drives, network cards, and digital video interfaces. Video for Windows provides all of the necessary tools for the development of the video capture utility in TRACE and allows for interchangeability of video capture boards without any software changes. TRACE is designed to take advantage of future upgrades in all aspects of its component hardware. A comparison of cloud extent determined by TRACE with manual method is included in this paper.

  11. Infant word recognition: Insights from TRACE simulations.

    Science.gov (United States)

    Mayor, Julien; Plunkett, Kim

    2014-02-01

    The TRACE model of speech perception (McClelland & Elman, 1986) is used to simulate results from the infant word recognition literature, to provide a unified, theoretical framework for interpreting these findings. In a first set of simulations, we demonstrate how TRACE can reconcile apparently conflicting findings suggesting, on the one hand, that consonants play a pre-eminent role in lexical acquisition (Nespor, Peña & Mehler, 2003; Nazzi, 2005), and on the other, that there is a symmetry in infant sensitivity to vowel and consonant mispronunciations of familiar words (Mani & Plunkett, 2007). In a second series of simulations, we use TRACE to simulate infants' graded sensitivity to mispronunciations of familiar words as reported by White and Morgan (2008). An unexpected outcome is that TRACE fails to demonstrate graded sensitivity for White and Morgan's stimuli unless the inhibitory parameters in TRACE are substantially reduced. We explore the ramifications of this finding for theories of lexical development. Finally, TRACE mimics the impact of phonological neighbourhoods on early word learning reported by Swingley and Aslin (2007). TRACE offers an alternative explanation of these findings in terms of mispronunciations of lexical items rather than imputing word learning to infants. Together these simulations provide an evaluation of Developmental (Jusczyk, 1993) and Familiarity (Metsala, 1999) accounts of word recognition by infants and young children. The findings point to a role for both theoretical approaches whereby vocabulary structure and content constrain infant word recognition in an experience-dependent fashion, and highlight the continuity in the processes and representations involved in lexical development during the second year of life.

  12. Infant word recognition: Insights from TRACE simulations☆

    Science.gov (United States)

    Mayor, Julien; Plunkett, Kim

    2014-01-01

    The TRACE model of speech perception (McClelland & Elman, 1986) is used to simulate results from the infant word recognition literature, to provide a unified, theoretical framework for interpreting these findings. In a first set of simulations, we demonstrate how TRACE can reconcile apparently conflicting findings suggesting, on the one hand, that consonants play a pre-eminent role in lexical acquisition (Nespor, Peña & Mehler, 2003; Nazzi, 2005), and on the other, that there is a symmetry in infant sensitivity to vowel and consonant mispronunciations of familiar words (Mani & Plunkett, 2007). In a second series of simulations, we use TRACE to simulate infants’ graded sensitivity to mispronunciations of familiar words as reported by White and Morgan (2008). An unexpected outcome is that TRACE fails to demonstrate graded sensitivity for White and Morgan’s stimuli unless the inhibitory parameters in TRACE are substantially reduced. We explore the ramifications of this finding for theories of lexical development. Finally, TRACE mimics the impact of phonological neighbourhoods on early word learning reported by Swingley and Aslin (2007). TRACE offers an alternative explanation of these findings in terms of mispronunciations of lexical items rather than imputing word learning to infants. Together these simulations provide an evaluation of Developmental (Jusczyk, 1993) and Familiarity (Metsala, 1999) accounts of word recognition by infants and young children. The findings point to a role for both theoretical approaches whereby vocabulary structure and content constrain infant word recognition in an experience-dependent fashion, and highlight the continuity in the processes and representations involved in lexical development during the second year of life. PMID:24493907

  13. Mass distribution for the two-photon channel

    CERN Multimedia

    ATLAS, collaboration

    2012-01-01

    Mass distribution for the two-photon channel. The strongest evidence for this new particle comes from analysis of events containing two photons. The smooth dotted line traces the measured background from known processes. The solid line traces a statistical fit to the signal plus background. The new particle appears as the excess around 126.5 GeV. The full analysis concludes that the probability of such a peak is three chances in a million.

  14. TXRF analysis of trace metals in thin silicon nitride films

    International Nuclear Information System (INIS)

    Vereecke, G.; Arnauts, S.; Verstraeten, K.; Schaekers, M.; Heyrts, M.M.

    2000-01-01

    As critical dimensions of integrated circuits continue to decrease, high dielectric constant materials such as silicon nitride are being considered to replace silicon dioxide in capacitors and transistors. The achievement of low levels of metal contamination in these layers is critical for high performance and reliability. Existing methods of quantitative analysis of trace metals in silicon nitride require high amounts of sample (from about 0.1 to 1 g, compared to a mass of 0.2 mg for a 2 nm thick film on a 8'' silicon wafer), and involve digestion steps not applicable to films on wafers or non-standard techniques such as neutron activation analysis. A novel approach has recently been developed to analyze trace metals in thin films with analytical techniques currently used in the semiconductor industry. Sample preparation consists of three steps: (1) decomposition of the silicon nitride matrix by moist HF condensed at the wafer surface to form ammonium fluosilicate. (2) vaporization of the fluosilicate by a short heat treatment at 300 o C. (3) collection of contaminants by scanning the wafer surface with a solution droplet (VPD-DSC procedure). The determination of trace metals is performed by drying the droplet on the wafer and by analyzing the residue by TXRF, as it offers the advantages of multi-elemental analysis with no dilution of the sample. The lower limits of detection for metals in 2 nm thick films on 8'' silicon wafers range from about 10 to 200 ng/g. The present study will focus on the matrix effects and the possible loss of analyte associated with the evaporation of the fluosilicate salt, in relation with the accuracy and the reproducibility of the method. The benefits of using an internal standard will be assessed. Results will be presented from both model samples (ammonium fluoride contaminated with metallic salts) and real samples (silicon nitride films from a production tool). (author)

  15. Temperature and Concentration Traces of Spray Flows During Motion in a Flame

    Directory of Open Access Journals (Sweden)

    Antonov Dmitry V.

    2016-01-01

    Full Text Available Heat and mass transfer models are developed on the base of experimental data and using Ansys Fluent software. These models allow prediction of the temperature and concentration traces of droplets. Transfer mechanisms of water droplets from different flames of flammable liquid (ethanol, kerosene И benzine with temperature gases 450–850 К are analyzed. The paper considers aerosol flows with droplets sizes of 0.04–0.4 mm and concentration of 3.8·10-5 –10.3·10-5 m3 of droplets/m3 of gas. The maximum gas temperature reduction in the trace of a moving liquid is ranged from 850 K to 600 K. The times of keeping the low temperature of the gas-vapor mixture in the droplets trace are from 13 s to 25 s relative to the initial gas temperature.

  16. Contents of trace elements in blood of healthy old people assayed by ICP-MS

    International Nuclear Information System (INIS)

    Wen Xinyu; Tong Hongli; Wang Ling; Zhou Heping; Tian Yaping

    2008-01-01

    To investigate the levels of 11 trace elements in serum of healthy old people to provide scientific basis for prevention and treatment of geriatric diseases, the serum were separated from blood samples according to standard procedure. The serum samples were underwent digestion, elimination of nitric acid, volume fixation and then assayed by inductively coupled plasma mass spectrometry. The results showed that the contents of Al in elderly people's serum is higher than those in young people (P<0.01), while the contents of V, Cr, Cu and Se in elderly people's serum were lower than those in young people (P<0.05). There were no significant differences in other trace elements between two groups. The contents of some trace elements in elderly people's serum changed significantly. (authors)

  17. Aerodynamic sampling for landmine trace detection

    Science.gov (United States)

    Settles, Gary S.; Kester, Douglas A.

    2001-10-01

    Electronic noses and similar sensors show promise for detecting buried landmines through the explosive trace signals they emit. A key step in this detection is the sampler or sniffer, which acquires the airborne trace signal and presents it to the detector. Practicality demands no physical contact with the ground. Further, both airborne particulates and molecular traces must be sampled. Given a complicated minefield terrain and microclimate, this becomes a daunting chore. Our prior research on canine olfactory aerodynamics revealed several ways that evolution has dealt with such problems: 1) proximity of the sniffer to the scent source is important, 2) avoid exhaling back into the scent source, 3) use an aerodynamic collar on the sniffer inlet, 4) use auxiliary airjets to stir up surface particles, and 5) manage the 'impedance mismatch' between sniffer and sensor airflows carefully. Unfortunately, even basic data on aerodynamic sniffer performance as a function of inlet-tube and scent-source diameters, standoff distance, etc., have not been previously obtained. A laboratory-prototype sniffer was thus developed to provide guidance for landmine trace detectors. Initial experiments with this device are the subject of this paper. For example, a spike in the trace signal is observed upon starting the sniffer airflow, apparently due to rapid depletion of the available signal-laden air. Further, shielding the sniffer from disruptive ambient airflows arises as a key issue in sampling efficiency.

  18. Forensic discrimination of copper wire using trace element concentrations.

    Science.gov (United States)

    Dettman, Joshua R; Cassabaum, Alyssa A; Saunders, Christopher P; Snyder, Deanna L; Buscaglia, JoAnn

    2014-08-19

    Copper may be recovered as evidence in high-profile cases such as thefts and improvised explosive device incidents; comparison of copper samples from the crime scene and those associated with the subject of an investigation can provide probative associative evidence and investigative support. A solution-based inductively coupled plasma mass spectrometry method for measuring trace element concentrations in high-purity copper was developed using standard reference materials. The method was evaluated for its ability to use trace element profiles to statistically discriminate between copper samples considering the precision of the measurement and manufacturing processes. The discriminating power was estimated by comparing samples chosen on the basis of the copper refining and production process to represent the within-source (samples expected to be similar) and between-source (samples expected to be different) variability using multivariate parametric- and empirical-based data simulation models with bootstrap resampling. If the false exclusion rate is set to 5%, >90% of the copper samples can be correctly determined to originate from different sources using a parametric-based model and >87% with an empirical-based approach. These results demonstrate the potential utility of the developed method for the comparison of copper samples encountered as forensic evidence.

  19. Simulation of reflooding on two parallel heated channel by TRACE

    Energy Technology Data Exchange (ETDEWEB)

    Zakir, Md. Ghulam [Department of Nuclear Engineering, Chalmers University of Technology, Gothenburg (Sweden)

    2016-07-12

    In case of Loss-Of-Coolant accident (LOCA) in a Boiling Water Reactor (BWR), heat generated in the nuclear fuel is not adequately removed because of the decrease of the coolant mass flow rate in the reactor core. This fact leads to an increase of the fuel temperature that can cause damage to the core and leakage of the radioactive fission products. In order to reflood the core and to discontinue the increase of temperature, an Emergency Core Cooling System (ECCS) delivers water under this kind of conditions. This study is an investigation of how the power distribution between two channels can affect the process of reflooding when the emergency water is injected from the top of the channels. The peak cladding temperature (PCT) on LOCA transient for different axial level is determined as well. A thermal-hydraulic system code TRACE has been used. A TRACE model of the two heated channels has been developed, and three hypothetical cases with different power distributions have been studied. Later, a comparison between a simulated and experimental data has been shown as well.

  20. Study on trace elements in gangue in Huainan mining area

    Energy Technology Data Exchange (ETDEWEB)

    Cai, F.; Liu, Z.; Lin, B.; Li, W.; Lu, Z. [Anhui University of Science and Technology, Huainan (China)

    2008-08-15

    46 samples were gathered from coal seams and rocks of various lithological types. In these samples, trace elements were analyzed by inductively coupled plasma-mass spectrometry (IAP-MS)and instrumental neutron activation analysis (IAA). Hg was analyzed by cold-vapor atomic absorption spectrometry (KVASS), F by ion-selective electrode (IS) and major elements by chemical methods. Eleven trace elements (Cd, Cu, Ni, Sn, Hg, Mn, As, Cr, Pb, Zn, F) were selected for study, and five of them, Cd, Cu, Ni, Sn, Hg, were above the background soil level (B.L.) of Huainan City, China and world averages. Respectively: Cd is 40 and 7 times the B.L. of Huainan City and the world; Cu is about 2 and 1.5 times the B.L. of Huainan City and the world; Ni is 8 and 7 times the B.L. of Huainan City and the world; Sn is 3 and 2 times the B.L. of Huainan City and the world; and Hg is 3,602 and 1,381 times the B.L. of Huainan City and the world. Their hazards caused to the environment of the mining area are explored primarily. It is thought that their hazards may be cumulative. 15 refs., 1 fig., 3 tabs.

  1. Trace contaminant control simulation computer program, version 8.1

    Science.gov (United States)

    Perry, J. L.

    1994-01-01

    The Trace Contaminant Control Simulation computer program is a tool for assessing the performance of various process technologies for removing trace chemical contamination from a spacecraft cabin atmosphere. Included in the simulation are chemical and physical adsorption by activated charcoal, chemical adsorption by lithium hydroxide, absorption by humidity condensate, and low- and high-temperature catalytic oxidation. Means are provided for simulating regenerable as well as nonregenerable systems. The program provides an overall mass balance of chemical contaminants in a spacecraft cabin given specified generation rates. Removal rates are based on device flow rates specified by the user and calculated removal efficiencies based on cabin concentration and removal technology experimental data. Versions 1.0 through 8.0 are documented in NASA TM-108409. TM-108409 also contains a source file listing for version 8.0. Changes to version 8.0 are documented in this technical memorandum and a source file listing for the modified version, version 8.1, is provided. Detailed descriptions for the computer program subprograms are extracted from TM-108409 and modified as necessary to reflect version 8.1. Version 8.1 supersedes version 8.0. Information on a separate user's guide is available from the author.

  2. Electric discharge for treatment of trace contaminants

    Science.gov (United States)

    Flamm, D. L.; Wydeven, T. J. (Inventor)

    1978-01-01

    A radio frequency glow discharge reactor is described for removing trace oxidizable contaminants from an oxygen bearing atmosphere. The reaction chamber is defined by an inner metal electrode facing a dielectric backed by an outer conductive electrode. In one embodiment, a conductive liquid forms the conductor of an outer electrode and cools the dielectric. A resonator coupled to a variable radio frequency source generates the high voltages for creating a glow discharge in the chamber at a predetermined pressure whereby the trace contaminants are oxidized into a few simple non-toxic products that may be easily recovered. The corresponding process for removal of trace contaminants from an oxygen-bearing atmosphere with high efficiency independent of the concentration level is also disclosed.

  3. Consumer perception of Brazilian traced beef

    Directory of Open Access Journals (Sweden)

    Júlio Otávio Jardim Barcellos

    2012-03-01

    Full Text Available The objective of this study was to determine consumers understanding of beef traceability, identifying how consumers value this meat and traceability elements to be presented on retail shelves. The method used in this study was a survey through the internet applying the Sphinx software. The sample consisted of 417 consumers, mostly living in Porto Alegre, Brazil. Consumers are aware of certified beef, consider it important, but this is not a demand. As to traced beef, most consumers (62.4% are in favor of mandatory traceability of beef cattle in Brazil, but 86.6% disagree with the destination of traced beef only to the foreign market. The majority of people are willing to pay more for traced beef and consider traceability a market opportunity, used as a differentiating tool.

  4. The Ring of Five follows the traces

    International Nuclear Information System (INIS)

    Anon.

    2015-01-01

    The Ring of Five is an informal network of European experts in radioactivity detection belonging to public bodies such as the IRSN. After having evoked different cases of detection (detection of unusual traces of iodine 131 in the region of Stockholm in 2015, detection of high levels of traces of caesium 137 in Switzerland in 1968) which leaded to the identification of the origin of these traces, this article briefly recalls the history of the creation of this network which extended with the occurrence of the Chernobyl accident, describes how the information is transmitted, the use of modelling tools, and outlines that the detection of some species can be associated either to a nuclear accident or to an atmospheric nuclear bomb test, and indicates how new sensors, not sensitive to humidity, have been developed after a lack of detection of iodine 131. In a brief interview, the future of the Ring of Five, topics to be studied and current projects are briefly evoked

  5. Selecting appropriate cases when tracing causal mechanisms

    DEFF Research Database (Denmark)

    Beach, Derek; Pedersen, Rasmus Brun

    2016-01-01

    The last decade has witnessed resurgence in the interest in studying the causal mechanisms linking causes and outcomes in the social sciences. This article explores the overlooked implications for case selection when tracing mechanisms using in-depth case studies. Our argument is that existing case...... selection guidelines are appropriate for research aimed at making cross-case claims about causal relationships, where case selection is primarily used to control for other causes. However, existing guidelines are not in alignment with case-based research that aims to trace mechanisms, where the goal...... is to unpack the causal mechanism between X and Y, enabling causal inferences to be made because empirical evidence is provided for how the mechanism actually operated in a particular case. The in-depth, within-case tracing of how mechanisms operate in particular cases produces what can be termed mechanistic...

  6. Trace elements levels in centenarian 'dodgers'.

    Science.gov (United States)

    Alis, Rafael; Santos-Lozano, Alejandro; Sanchis-Gomar, Fabian; Pareja-Galeano, Helios; Fiuza-Luces, Carmen; Garatachea, Nuria; Lucia, Alejandro; Emanuele, Enzo

    2016-05-01

    Trace element bioavailability can play a role in several metabolic and physiological pathways known to be altered during the aging process. We aimed to explore the association of trace elements with increased lifespan by analyzing the circulating levels of seven trace elements (Cr, Cu, Fe, Mn, Mo, Se and Zn) in a cohort of healthy centenarians or 'dodgers' (≥100 years, free of major age-related diseases) in comparison with sex-matched younger elderly controls. Centenarians showed significant lower Cu (783.7 (76.7, 1608.9) vs 962.5 (676.3, 2064.4)μg/mL, Pdodgers', and, therefore, at least partly, be involved in the healthy aging phenotype shown by these subjects. These results should be confirmed in larger cohorts of other geographic/ethnic origin and the potential cause-effect association tested in mechanistic experimental settings. Copyright © 2016 Elsevier GmbH. All rights reserved.

  7. La formule des traces locale tordue

    CERN Document Server

    Moeglin, Colette

    2018-01-01

    A note to readers: This book is in French. The text has two chapters. The first one, written by Waldspurger, proves a twisted version of the local trace formula of Arthur over a local field. This formula is an equality between two expressions, one involving weighted orbital integrals, the other one involving weighted characters. The authors follow Arthur's proof, but the treatement of the spectral side is more complicated in the twisted situation. They need to use the combinatorics of the "Morning Seminar". The authors' local trace formula has the same consequences as in Arthur's paper on elliptic characters. The second chapter, written by Moeglin, gives a symmetric form of the local trace formula as in Arthur's paper on Fourier Transform of Orbital integral and describes any twisted orbital integral, in the p-adic case, as integral of characters.

  8. Potential of IRMS technology for tracing gamma-butyrolactone (GBL).

    Science.gov (United States)

    Marclay, François; Pazos, Diego; Delémont, Olivier; Esseiva, Pierre; Saudan, Christophe

    2010-05-20

    Popularity of gamma-hydroxybutyric acid (GHB) is fairly stable among drug users, while the consumption of its chemical precursor, gamma-butyrolactone (GBL), is a growing phenomenon. Although conventional analytical methods allow to detect this substance in various matrices, linking a trace and a source is still a difficult challenge. However, as several synthesis pathways and chemical precursors exist for the production of GBL, its carbon isotopic signature may vary extensively. For that purpose, a method has been developed to determine the carbon isotopes content of GBL by means of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). The delta(13)C-values of 19 bulk samples purchased worldwide were in the range from -23.1 to -45.8 per thousand (SDIRMS for discriminating between seizures of GBL and for source determination.

  9. Trace element analysis in soy sauce. 2

    International Nuclear Information System (INIS)

    Haruyama, Yoichi; Saito, Manabu; Tomita, Michio; Yoshida, Koji.

    1994-01-01

    Trace elements in four kinds of soybean and three kinds of salt have been measured by means of in-air PIXE. In soybeans, which were made in Japan, America, Canada and China, six kinds of trace elements were detected, such as Mn, Fe, Ni, Cu, Zn and Br. The concentration of these elements varied depending on the place they were made. American soybean showed characteristic feature compared with other soybeans. As to the bromine concentration, American soybean contains ten times as much as Japanese one. In salts Br and Sr were detected. (author)

  10. Trace element analysis in soy sauce

    International Nuclear Information System (INIS)

    Haruyama, Yoichi; Saito, Manabu; Tomiya, Michio

    1993-01-01

    Trace elements in soy sauce have been measured by means of in-air PIXE. Six kinds of trace elements were detected, such as Mn, Fe, Ni, Zn, Cu and Br. Concentrations of Mn, Fe, Zn and Br which were observed in all samples, have been determined. Each analyzed sample contained considerable amount of Br about 160 ppm. Comparison of Br content of the imported raw materials with those of the domestic ones suggested that the large amount of Br was the residual fumigation chemicals in the imported raw materials. (author)

  11. The Alba ray tracing code: ART

    Science.gov (United States)

    Nicolas, Josep; Barla, Alessandro; Juanhuix, Jordi

    2013-09-01

    The Alba ray tracing code (ART) is a suite of Matlab functions and tools for the ray tracing simulation of x-ray beamlines. The code is structured in different layers, which allow its usage as part of optimization routines as well as an easy control from a graphical user interface. Additional tools for slope error handling and for grating efficiency calculations are also included. Generic characteristics of ART include the accumulation of rays to improve statistics without memory limitations, and still providing normalized values of flux and resolution in physically meaningful units.

  12. Comparative evaluation of trace elements in blood

    International Nuclear Information System (INIS)

    Goeij, J.J.M. de; Tjioe, P.S.; Pries, C.; Zwiers, J.H.L.

    1976-01-01

    The Interuniversitair Reactor Instituut and the Centraal Laboratorium TNO have carried out a common investigation on neutron-activation-analytical procedures for the determination of trace elements in blood. A comparative evaluation of five methods, destructive as well as non-destructive, is given. The sensitivity and reproducibility of the procedures are discussed. By combining some of the methods it is possible, starting with 1 ml blood, to give quantitative information on 14 important trace elements: antimony, arsenic, bromine, cadmium, cobalt, gold, copper, mercury, molybdenum, nickel, rubidium, selenium, iron and zinc. The methods have also been applied to sodium, chromium and potassium

  13. Tracking Oxidation During Transport of Trace Gases in Air from the Northern to Southern Hemisphere

    Science.gov (United States)

    Montzka, S. A.; Moore, F. L.; Atlas, E. L.; Parrish, D. D.; Miller, B. R.; Sweeney, C.; McKain, K.; Hall, B. D.; Siso, C.; Crotwell, M.; Hintsa, E. J.; Elkins, J. W.; Blake, D. R.; Barletta, B.; Meinardi, S.; Claxton, T.; Hossaini, R.

    2017-12-01

    Trace gas mole fractions contain the imprint of recent influences on an air mass such as sources, transport, and oxidation. Covariations among the many gases measured from flasks during ATom and HIPPO, and from the ongoing NOAA cooperative air sampling program enable recent influences to be identified from a wide range of sources including industrial activity, biomass burning, emissions from wetlands, and uptake by terrestrial ecosystems. In this work we explore the evolution of trace gas concentrations owing to atmospheric oxidation as air masses pass through the tropics, the atmospheric region with the highest concentrations of the hydroxyl radical. Variations in C2-C5 hydrocarbon concentrations downwind of source regions provide a measure of photochemical ageing in an air mass since emission, but they become less useful when tracking photochemical ageing as air is transported from the NH into the SH owing to their low mixing ratios, lifetimes that are very short relative to transport times, non-industrial sources in the tropics (e.g., biomass burning), and southern hemispheric sources. Instead, we consider a range of trace gases and trace gas pairs that provide a measure of photochemical processing as air transits the tropics. To be useful in this analysis, these trace gases would have lifetimes comparable to interhemispheric transport times, emissions arising from only the NH at constant relative magnitudes, and concentrations sufficient to allow precise and accurate measurements in both hemispheres. Some anthropogenically-emitted chlorinated hydrocarbons meet these requirements and have been measured during ATom, HIPPO, and from NOAA's ongoing surface sampling efforts. Consideration of these results and their implications for tracking photochemical processing in air as it is transported across the tropics will be presented.

  14. Composition of Trace Metals in Dust Samples Collected from Selected High Schools in Pretoria, South Africa

    Directory of Open Access Journals (Sweden)

    J. O. Olowoyo

    2016-01-01

    Full Text Available Potential health risks associated with trace metal pollution have necessitated the importance of monitoring their levels in the environment. The present study investigated the concentrations and compositions of trace metals in dust samples collected from classrooms and playing ground from the selected high schools In Pretoria. Schools were selected from Pretoria based on factors such as proximity to high traffic ways, industrial areas, and residential areas. Thirty-two dust samples were collected from inside and outside the classrooms, where learners often stay during recess period. The dust samples were analysed for trace metal concentrations using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS. The composition of the elements showed that the concentrations of Zn were more than all other elements except from one of the schools. There were significant differences in the concentrations of trace metals from the schools (p<0.05. Regular cleaning, proximity to busy road, and well maintained gardens seem to have positive effects on the concentrations of trace metals recorded from the classrooms dust. The result further revealed a positive correlation for elements such as Pb, Cu, Zn, Mn, and Sb, indicating that the dust might have a common source.

  15. Trace element structure of the most widespread plants of genus PulmonariaFNx01

    Directory of Open Access Journals (Sweden)

    Dmitriy Kruglov

    2012-01-01

    Full Text Available Aim: The aim of this work was a comparative research of trace element structure of various organs of three Pulmonaria species. Materials and Methods: The aerial parts of the most widespread plants of genus Pulmonaria such as Pulmonaria officinalis L., Pulmonaria obscura Dumort. and Pulmonaria mollis Wulf. ex Hornem., which were collected in ending of flowering and were used as the research objects. The amount of trace elements (B, K, P, V, Ca, Co, Cu, Fe, Mg, Mn, Mo, Na, Si, Zn, Ag, Al, Ba, Br, Cr, I, Ni, Se, Sr, and Ti was determined by means of mass spectroscopy with inductively coupled plasma. Results: The data clustering has shown that floral shoots and rosellate leaves possess essentially various trace element status. At the same time, the trace elements′ status of organs of researched plants poorly depends on a taxonomic position of the plant. Thereupon, it is obvious that pharmacological activity is defined by organs of plants from which medicines were made, but not by a species of the used plant. Conclusions: The significant distinction in pharmacological activity of preparations depends on the trace elements′ status of used medicinal vegetative raw materials.

  16. Mass Sports

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2017-03-01

    Fitness has become one of the most popular kinds of the mass sport and has completely replaced the traditional “physical culture”. Dozens of variations of fitness and millions of participants pose a great challenge to contemporary architecture. The articles of our issue show the present and the future of architecture for fitness. We present a topical collection with a wide geographical range, including the Irkutsk Agglomeration, Tomsk, Krasnodar, sports in the Moscow Palace of Young Pioneers, and the anthology of the top foreign sports venues.

  17. Critical Mass

    CERN Multimedia

    AUTHOR|(CDS)2070299

    2017-01-01

    Critical Mass is a cycling event typically held on the last Friday of every month; its purpose is not usually formalized beyond the direct action of meeting at a set location and time and traveling as a group through city or town streets on bikes. The event originated in 1992 in San Francisco; by the end of 2003, the event was being held in over 300 cities around the world. At CERN it is held once a year in conjunction with the national Swiss campaing "Bike to work".

  18. Techniques for the measurement of trace moisture in high-purity electronic specialty gases

    International Nuclear Information System (INIS)

    Funke, Hans H.; Grissom, Brad L.; McGrew, Clark E.; Raynor, Mark W.

    2003-01-01

    The control of water vapor (moisture) contamination in process gases is critical to the successful manufacture of semiconductor devices. As specified moisture levels have become more stringent, there is a growing demand for more sensitive analytical methods. Instrumental methods currently being used or in development for measuring trace moisture at ppbv levels include Fourier transform infrared spectroscopy, tunable diode laser absorption spectroscopy, cavity ringdown spectroscopy, intracavity laser spectroscopy, electron impact ionization mass spectrometry, and atmospheric pressure ionization mass spectrometry. In addition, sensor-based technologies such as oscillating quartz crystal microbalances, and chilled mirror-, capacitor-, and electrolytic-based hygrometers operate in this regime. These approaches are presented and reviewed. As the success of each trace moisture method is dependent on the degree to which the different process gases interfere with the measurement process, important process gas applications of the techniques are highlighted. Advantages and disadvantages as well as future developments and trends are also presented

  19. Plasma trace metals during total parenteral alimentation.

    Science.gov (United States)

    Solomons, N W; Layden, T J; Rosenberg, I H; Vo-Khactu, K; Sandstead, H H

    1976-06-01

    The plasma concentrations of the trace metals zinc and copper were studied prospectively in 13 patients with gastrointestinal diseases treated with parenteral alimentation (TPA) for periods of from 8 days to 7 1/2 weeks. Plasma copper levels fell rapidly and consistently in all patients, with an overall rate of - 11 mug per 100 ml per week. Zinc concentrations declined in 10 of 13 patients at a more gradual rate. Analysis of the standard parenteral alimentation fluids revealed zinc content equivalent to 50% of the daily requirement and a negligible content of copper. From combined analysis of plasma zinc, hair zinc, and taste acuity, there is evidence that increased utilization or redistribution within the body may effect plasma concentrations in some patients. Neither an increase in urinary excretion nor a primary decrease in plasma binding proteins appeared to be a major factor in lowering plasma trace metal concentrations. These findings indicate that a marked decrease in plasma copper is regular and a decline in plasma zinc is common during TPA using fluids unsupplemented with trace metals. Supplementation of parenteral alimentation fluids with the trace metals zinc and copper is recommended.

  20. Trace Elements in Human Nutrition and Health

    African Journals Online (AJOL)

    Trace Elements in Human Nutrition and Health, a report of a. World Heatth Organisation Expert Committee, contains material contributed by numerous experts consulted in different specialised fields, together with the conClusions reached and recommendations made by the Expert. Consultation. The nineteen nutritionally ...

  1. Trace elements in glucometabolic disorders: an update

    Directory of Open Access Journals (Sweden)

    Wiernsperger Nicolas

    2010-12-01

    Full Text Available Abstract Many trace elements, among which metals, are indispensable for proper functioning of a myriad of biochemical reactions, more particularly as enzyme cofactors. This is particularly true for the vast set of processes involved in regulation of glucose homeostasis, being it in glucose metabolism itself or in hormonal control, especially insulin. The role and importance of trace elements such as chromium, zinc, selenium, lithium and vanadium are much less evident and subjected to chronic debate. This review updates our actual knowledge concerning these five trace elements. A careful survey of the literature shows that while theoretical postulates from some key roles of these elements had led to real hopes for therapy of insulin resistance and diabetes, the limited experience based on available data indicates that beneficial effects and use of most of them are subjected to caution, given the narrow window between safe and unsafe doses. Clear therapeutic benefit in these pathologies is presently doubtful but some data indicate that these metals may have a clinical interest in patients presenting deficiencies in individual metal levels. The same holds true for an association of some trace elements such as chromium or zinc with oral antidiabetics. However, this area is essentially unexplored in adequate clinical trials, which are worth being performed.

  2. Atmospheric trace metal concentrations in Suspended Particulate ...

    African Journals Online (AJOL)

    The air particulate samples were collected from the kitchens, living rooms and outdoor environment of five households in the community. The quantification of the trace metals was done using Atomic Absorption spectrometry method, employing HNO based wet digestion. High baseline concentration of SPMwere obtained ...

  3. Trace elements in relation to cardiovascular diseases

    Energy Technology Data Exchange (ETDEWEB)

    Masironi, R [World Health Organization, Cardiovascular Diseases Unit, Geneva (Switzerland); Parr, R M [International Atomic Energy Agency, Medical Applications Section, Vienna (Austria)

    1973-07-01

    For the past four years the World Health Organization and the International Atomic Energy-Agency have been jointly coordinating investigations at an international level on the role possibly played by stable trace elements in the aetiology of cardiovascular diseases, and the use of nuclear techniques in studying these elements. (author)

  4. Authoring Model-Tracing Cognitive Tutors

    Science.gov (United States)

    Blessing, Stephen B.; Gilbert, Stephen B.; Ourada, Stephen; Ritter, Steven

    2009-01-01

    Intelligent Tutoring Systems (ITSs) that employ a model-tracing methodology have consistently shown their effectiveness. However, what evidently makes these tutors effective, the cognitive model embedded within them, has traditionally been difficult to create, requiring great expertise and time, both of which come at a cost. Furthermore, an…

  5. Papa, a Particle Tracing Code in Pascal

    NARCIS (Netherlands)

    Haselhoff, E.H.; Haselhoff, Eltjo H.; Ernst, G.J.

    1990-01-01

    During the design of a 10 ¿m high-gain FEL oscillator (TEUFEL Project) we developed a new particle-tracing code to perform simulations of thermionic- and photo-cathode electron injectors/accelerators. The program allows predictions of current, energy and beam emittance in a user-specified linac

  6. Urban environmental geochemistry of trace metals

    International Nuclear Information System (INIS)

    Wong, Coby S.C.; Li Xiangdong; Thornton, Iain

    2006-01-01

    As the world's urban population continues to grow, it becomes increasingly imperative to understand the dynamic interactions between human activities and the urban environment. The development of urban environmental geochemistry has yielded a significant volume of scientific information about geochemical phenomena found uniquely in the urban environment, such as the distribution, dispersion, and geochemical characteristics of some toxic and potentially toxic trace metals. The aim of this paper is to provide an overview of the development of urban environmental geochemistry as a field of scientific study and highlight major transitions during the course of its development from its establishment to the major scientific interests in the field today. An extensive literature review is also conducted of trace metal contamination of the urban terrestrial environment, in particular of urban soils, in which the uniqueness of the urban environment and its influences on trace metal contamination are elaborated. Potential areas of future development in urban environmental geochemistry are identified and discussed. - Urban environmental geochemistry as a scientific discipline provides valuable information on trace metal contamination of the urban environment and its associated health effects

  7. Leave no trace in the outdoors

    Science.gov (United States)

    Marion, Jeffrey L.

    2014-01-01

    The essential guide for enjoying the outdoors without harming the environment. - Details the seven core principles of Leave No Trace ethics and practices - Covers hiking, campfires, food storage, and personal hygiene - Endorsed by the USDI National Park Service, Bureau of Land Management, Fish & Wildlife Service, U.S. Geological Survey, and the USDA Forest Service

  8. Software for computerised analysis of cardiotocographic traces.

    Science.gov (United States)

    Romano, M; Bifulco, P; Ruffo, M; Improta, G; Clemente, F; Cesarelli, M

    2016-02-01

    Despite the widespread use of cardiotocography in foetal monitoring, the evaluation of foetal status suffers from a considerable inter and intra-observer variability. In order to overcome the main limitations of visual cardiotocographic assessment, computerised methods to analyse cardiotocographic recordings have been recently developed. In this study, a new software for automated analysis of foetal heart rate is presented. It allows an automatic procedure for measuring the most relevant parameters derivable from cardiotocographic traces. Simulated and real cardiotocographic traces were analysed to test software reliability. In artificial traces, we simulated a set number of events (accelerations, decelerations and contractions) to be recognised. In the case of real signals, instead, results of the computerised analysis were compared with the visual assessment performed by 18 expert clinicians and three performance indexes were computed to gain information about performances of the proposed software. The software showed preliminary performance we judged satisfactory in that the results matched completely the requirements, as proved by tests on artificial signals in which all simulated events were detected from the software. Performance indexes computed in comparison with obstetricians' evaluations are, on the contrary, not so satisfactory; in fact they led to obtain the following values of the statistical parameters: sensitivity equal to 93%, positive predictive value equal to 82% and accuracy equal to 77%. Very probably this arises from the high variability of trace annotation carried out by clinicians. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Improved backward ray tracing with stochastic sampling

    Science.gov (United States)

    Ryu, Seung Taek; Yoon, Kyung-Hyun

    1999-03-01

    This paper presents a new technique that enhances the diffuse interreflection with the concepts of backward ray tracing. In this research, we have modeled the diffuse rays with the following conditions. First, as the reflection from the diffuse surfaces occurs in all directions, it is impossible to trace all of the reflected rays. We confined the diffuse rays by sampling the spherical angle out of the reflected rays around the normal vector. Second, the traveled distance of reflected energy from the diffuse surface differs according to the object's property, and has a comparatively short reflection distance. Considering the fact that the rays created on the diffuse surfaces affect relatively small area, it is very inefficient to trace all of the sampled diffused rays. Therefore, we set a fixed distance as the critical distance and all the rays beyond this distance are ignored. The result of this research is that as the improved backward ray tracing can model the illumination effects such as the color bleeding effects, we can replace the radiosity algorithm under the limited environment.

  10. Trace Metals Bioaccumulation Potentials of Three Indigenous ...

    African Journals Online (AJOL)

    The rapid increase in the number of industries may have increased the levels of trace metals in the soil. Phytoremediation of these polluted soils using indigenous grasses is now considered an alternative method in remediating these polluted soils. The present study investigated and compared the ability of three ...

  11. Backward ray tracing for ultrasonic imaging

    NARCIS (Netherlands)

    Breeuwer, R.

    1990-01-01

    Focused ultrasonic beams frequently pass one or more media interfaces, strongly affecting the ultrasonic beamshape and focusing. A computer program, based on backward ray tracing was developed to compute the shape of a corrected focusing mirror. This shape is verified with another program; then the

  12. AXAF FITS standard for ray trace interchange

    Science.gov (United States)

    Hsieh, Paul F.

    1993-07-01

    A standard data format for the archival and transport of x-ray events generated by ray trace models is described. Upon review and acceptance by the Advanced X-ray Astrophysics Facility (AXAF) Software Systems Working Group (SSWG), this standard shall become the official AXAF data format for ray trace events. The Flexible Image Transport System (FITS) is well suited for the purposes of the standard and was selected to be the basis of the standard. FITS is both flexible and efficient and is also widely used within the astronomical community for storage and transfer of data. In addition, software to read and write FITS format files are widely available. In selecting quantities to be included within the ray trace standard, the AXAF Mission Support team, Science Instruments team, and the other contractor teams were surveyed. From the results of this survey, the following requirements were established: (1) for the scientific needs, each photon should have associated with it: position, direction, energy, and statistical weight; the standard must also accommodate path length (relative phase), and polarization. (2) a unique photon identifier is necessary for bookkeeping purposes; (3) a log of individuals, organizations, and software packages that have modified the data must be maintained in order to create an audit trail; (4) a mechanism for extensions to the basic kernel should be provided; and (5) the ray trace standard should integrate with future AXAF data product standards.

  13. Trace anomalies and chiral Ward identities

    International Nuclear Information System (INIS)

    Yang Jifeng

    2004-01-01

    In a simple Abelian spinor field theory, the canonical trace identities for certain axial-vector and axial-scalar operators are re-examined in dimensional regularization, some disagreements with previous results are found and an interesting new phenomenon is observed and briefly discussed

  14. Double-trace flows and the swampland

    Science.gov (United States)

    Giombi, Simone; Perlmutter, Eric

    2018-03-01

    We explore the idea that large N, non-supersymmetric conformal field theories with a parametrically large gap to higher spin single-trace operators may be obtained as infrared fixed points of relevant double-trace deformations of superconformal field theories. After recalling the AdS interpretation and some potential pathologies of such flows, we introduce a concrete example that appears to avoid them: the ABJM theory at finite k, deformed by \\int O^2, where O is the superconformal primary in the stress-tensor multiplet. We address its relation to recent conjectures based on weak gravity bounds, and discuss the prospects for a wider class of similarly viable flows. Next, we proceed to analyze the spectrum and correlation functions of the putative IR CFT, to leading non-trivial order in 1 /N. This includes analytic computations of the change under double-trace flow of connected four-point functions of ABJM superconformal primaries; and of the IR anomalous dimensions of infinite classes of double-trace composite operators. These would be the first analytic results for anomalous dimensions of finite-spin composite operators in any large N CFT3 with an Einstein gravity dual.

  15. Tracing pathogens in the food chain

    NARCIS (Netherlands)

    Brul, S.; Fratamico, P.M.; McMeekin, T.A.

    2010-01-01

    Successful methods for the detection and investigation of outbreaks of foodborne disease are essential for ensuring consumer safety. Increased understanding of the transmission of pathogens in food chains will also assist efforts to safeguard public health. Tracing pathogens in the food chain

  16. Trace element inhibition of phytase activity.

    Science.gov (United States)

    Santos, T; Connolly, C; Murphy, R

    2015-02-01

    Nowadays, 70 % of global monogastric feeds contains an exogenous phytase. Phytase supplementation has enabled a more efficient utilisation of phytate phosphorous (P) and reduction of P pollution. Trace minerals, such as iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) are essential for maintaining health and immunity as well as being involved in animal growth, production and reproduction. Exogenous sources of phytase and trace elements are regularly supplemented to monogastric diets and usually combined in a premix. However, the possibility for negative interaction between individual components within the premix is high and is often overlooked. Therefore, this initial study focused on assessing the potential in vitro interaction between inorganic and organic chelated sources of Fe, Zn, Cu and Mn with three commercially available phytase preparations. Additionally, this study has investigated if the degree of enzyme inhibition was dependent of the type of chelated sources. A highly significant relationship between phytase inhibition, trace mineral type as well as mineral source and concentration, p phytases for Fe and Zn, as well as for Cu with E. coli and Aspergillus niger phytases. Different chelate trace mineral sources demonstrated diversifying abilities to inhibit exogenous phytase activity.

  17. Biological trace element measurements using synchrotron radiation

    International Nuclear Information System (INIS)

    Giauque, R.D.; Jaklevic, J.M.; Thompson, A.C.

    1985-07-01

    The feasibility of performing x-ray fluorescence trace element determinations at concentrations substantially below the ppM level for biological materials is demonstrated. Conditions for achieving optimum sensitivity were ascertained. Results achieved for five standard reference materials were, in most cases, in excellent agreement with listed values. Minimum detectable limits of 20 ppM were measured for most elements

  18. Tracing And Control Of Engineering Requirements

    Science.gov (United States)

    Turner, Philip R.; Stoller, Richard L.; Neville, Ted; Boyle, Karen A.

    1991-01-01

    TRACER (Tracing and Control of Engineering Requirements) is data-base/word-processing software system created to document and maintain order of both requirements and descriptions associated with engineering project. Implemented on IBM PC under PC-DOS. Written with CLIPPER.

  19. Trace elements in wine and other beverages

    International Nuclear Information System (INIS)

    Eschnauer, H.

    1974-01-01

    Survey of the mostly physical methods of analysis (e.g. activation analysis) for the dectection of trace elements in wine and in other alcoholic and non-alcoholic beverages as well as for detection of radioactivity (natural and man-made) in these beverages. (HP) [de

  20. Trace elements partitioning during coal combustion in fluidized bed under O{sub 2}/CO{sub 2} atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haixin; Zhao, Changsui; Liang, Cai; Duan, Lunbo; Chen, Huichao [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    Experiments were conducted to investigate the effects of temperature and O{sub 2}/CO{sub 2} atmosphere on trace elements (Cr, Mn, Co, Ni, Cd, Pb, Hg, As, Se) partitioning during combustion of Xuzhou bituminous coal in a 6 kWth fluidized bed. Inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS) were used to determine trace elements contents in raw coal, bottom ash, fly ash and flue gas. The results indicate that with bed temperature increase, the relative enrichment of all the trace elements except Cr in bottom ash decreases suggesting that their volatility is enhanced. The relative enrichments of hardly volatile elements, like Cr and Mn in fly ash increase with bed temperature increase while those of partially volatile and highly volatile elements in fly ash are opposite. The relative enrichments of trace elements except Cr and Mn in fly ash are higher than those in bottom ash. Increasing bed temperature promotes elements like As, Se and Hg to migrate to vapor phase, Mn to migrate to fly ash and Cr to migrate to both bottom ash and fly ash. 21%O{sub 2}/79%CO{sub 2} atmosphere improves the volatility of Cr, Mn, Co, Se and their migration to fly ash, while restrains the volatility of As, Ni, Pb. It has little effect on the volatility of Hg but improves its migration to fly ash. Mass balance ratio was also calculated to observe trace elements distribution in bottom ash, fly ash and flue gas. There is no much difference in trace elements distribution between the two atmospheres. It can be seen that the trace elements proportion in fly ash is much greater, and more than 40% of Hg is distributed in the gas phase. Most of Hg and Se volatilize during combustion. The mass balance ratios are 87 {proportional_to} 129% which is considered acceptable.

  1. Green's functions and trace formulas for generalized Sturm-Liouville problems related by Darboux transformations

    International Nuclear Information System (INIS)

    Schulze-Halberg, Axel

    2010-01-01

    We study Green's functions of the generalized Sturm-Liouville problems that are related to each other by Darboux -equivalently, supersymmetrical - transformations. We establish an explicit relation between the corresponding Green's functions and derive a simple formula for their trace. The class of equations considered here includes the conventional Schroedinger equation and generalizations, such as for position-dependent mass and with linearly energy-dependent potential, as well as the stationary Fokker-Planck equation.

  2. Tracing the first stars and galaxies of the Milky Way

    Science.gov (United States)

    Griffen, Brendan F.; Dooley, Gregory A.; Ji, Alexander P.; O'Shea, Brian W.; Gómez, Facundo A.; Frebel, Anna

    2018-02-01

    We use 30 high-resolution dark matter haloes of the Caterpillar simulation suite to probe the first stars and galaxies of Milky Way-mass systems. We quantify the environment of the high-z progenitors of the Milky Way and connect them to the properties of the host and satellites today. We identify the formation sites of the first generation of Population III (Pop III) stars (z ˜ 25) and first galaxies (z ˜ 22) with several different models based on a minimum halo mass. This includes a simple model for radiative feedback, the primary limitation of the model. Through this method we find approximately 23 000 ± 5000 Pop III potentially star-forming sites per Milky Way-mass host, though this number is drastically reduced to ˜550 star-forming sites if feedback is included. The majority of these haloes identified form in isolation (96 per cent at z = 15) and are not subject to external enrichment by neighbouring haloes (median separation ˜1 kpc at z = 15), though half merge with a system larger than themselves within 1.5 Gyr. Using particle tagging, we additionally trace the Pop III remnant population to z = 0 and find an order of magnitude scatter in their number density at small (i.e. r 50 kpc) galactocentric radii. We provide fitting functions for determining the number of progenitor minihalo and atomic cooling halo systems that present-day satellite galaxies might have accreted since their formation. We determine that observed dwarf galaxies with stellar masses below 104.6 M⊙ are unlikely to have merged with any other star-forming systems.

  3. Critical review of conservation equations for two-phase flow in the U.S. NRC TRACE code

    International Nuclear Information System (INIS)

    Wulff, Wolfgang

    2011-01-01

    Research highlights: → Field equations as implemented in TRACE are incorrect. → Boundary conditions needed for cooling of nuclear fuel elements are wrong. → The two-fluid model in TRACE is not closed. → Three-dimensional flow modeling in TRACE has no basis. - Abstract: The field equations for two-phase flow in the computer code TRAC/RELAP Advanced Computational Engine or TRACE are examined to determine their validity, their capabilities and limitations in resolving nuclear reactor safety issues. TRACE was developed for the NRC to predict thermohydraulic phenomena in nuclear power plants during operational transients and postulated accidents. TRACE is based on the rigorously derived and well-established two-fluid field equations for 1-D and 3-D two-phase flow. It is shown that: (1)The two-fluid field equations for mass conservation as implemented in TRACE are wrong because local mass balances in TRACE are in conflict with mass conservation for the whole reactor system, as shown in Section . (2)Wrong equations of motion are used in TRACE in place of momentum balances, compromising at branch points the prediction of momentum transfer between, and the coupling of, loops in hydraulic networks by impedance (form loss and wall shear) and by inertia and thereby the simulation of reactor component interactions. (3)Most seriously, TRACE calculation of heat transfer from fuel elements is incorrect for single and two-phase flows, because Eq. of the TRACE Manual is wrong (see Section ). (4)Boundary conditions for momentum and energy balances in TRACE are restricted to flow regimes with single-phase wall contact because TRACE lacks constitutive relations for solid-fluid exchange of momentum and heat in prevailing flow regimes. Without a quantified assessment of consequences from (3) to (4), predictions of phasic fluid velocities, fuel temperatures and important safety parameters, e.g., peak clad temperature, are questionable. Moreover, TRACE cannot predict 3-D single- or

  4. Mass Spectrometric Analysis for Nuclear Safeguards

    International Nuclear Information System (INIS)

    Boulyga, S.

    2013-01-01

    The release of man-made radionuclides into the environment results in contamination that carries specific isotopic signatures according to the release scenarios and the previous usage of materials and facilities. In order to trace the origin of such contamination and/or to assess the potential impact on the public and environmental health, it is necessary to determine the isotopic composition and activity concentrations of radionuclides in environmental samples in an accurate and timely fashion. Mass spectrometric techniques, such as thermal ionization mass spectrometry (TIMS), secondary ion mass spectrometry (SIMS), and inductively coupled plasma mass spectrometry (ICP-MS) belong to the most powerful methods for analysis of nuclear and related samples in nuclear safeguards, forensics, and environmental monitoring. This presentation will address the potential of mass spectrometric analysis of actinides at ultra-trace concentration levels, isotopic analysis of micro-samples, age determination of nuclear materials as well as identification and quantification of elemental and isotopic signatures of nuclear samples in general. (author)

  5. Trace elements record complex histories in diogenites

    Science.gov (United States)

    Balta, J. B.; Beck, A. W.; McSween, H. Y.

    2012-12-01

    Diogenite meteorites are cumulate rocks composed mostly of orthopyroxene and chemically linked to eucrites (basaltic) and howardites (brecciated mixtures of diogenites and eucrites). Together, they represent the largest single family of achondrite meteorites delivered to Earth, and have been spectrally linked to the asteroid 4 Vesta, the largest remaining basaltic protoplanet. However, this spectral link is non-unique as many basaltic asteroids likely formed and were destroyed in the early solar system. Recent work suggested that Vesta may be an unlikely parent body for the diogenites based on correlations between trace elements and short-lived isotope decay products, which would be unlikely to survive on a body as large as Vesta due to its long cooling history [1]. Recent analyses of terrestrial and martian olivines have demonstrated that trace element spatial distributions can preserve evidence of their crystallization history even when major elements have been homogenized [2]. We have mapped minor elements including Cr, Al, and Ti in seemingly homogeneous diogenite orthopyroxenes and found a variety of previously unobserved textures. The pyroxenes in one sample (GRA 98108) are seemingly large grains of variable shapes and sizes, but the trace elements reveal internal grain boundaries between roughly-equal sized original subgrains, with equilibrated metamorphic triple junctions between them and trace element depletions at the boundaries. These trends suggest extraction of trace elements by a magma along those relict grain boundaries during a reheating event. Two other samples show evidence of fracturing and annealing, with trace element mobility within grains. One sample appears to have remained a closed system during annealing (MET 01084), while the other has interacted with a fluid or magma to move elements along annealed cracks (LEW 88679). These relict features establish that the history of diogenite pyroxenes is more complex than their homogeneous major

  6. Trace element emissions from spontaneous combustion of gob piles in coal mines, Shanxi, China

    Science.gov (United States)

    Zhao, Y.; Zhang, Jiahua; Chou, C.-L.; Li, Y.; Wang, Z.; Ge, Y.; Zheng, C.

    2008-01-01

    The emissions of potentially hazardous trace elements from spontaneous combustion of gob piles from coal mining in Shanxi Province, China, have been studied. More than ninety samples of solid waste from gob piles in Shanxi were collected and the contents of twenty potentially hazardous trace elements (Be, F, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sn, Sb, Hg, Tl, Pb, Th, and U) in these samples were determined. Trace element contents in solid waste samples showed wide ranges. As compared with the upper continental crust, the solid waste samples are significantly enriched in Se (20x) and Tl (12x) and are moderately enriched in F, As, Mo, Sn, Sb, Hg, Th, and U (2-5x). The solid waste samples are depleted in V, Cr, Mn, Co, Ni, Cu, and Zn. The solid waste samples are enriched in F, V, Mn, Cr, Co, Ni, Cu, Zn, Sb, Th, and U as compared with the Shanxi coals. Most trace elements are higher in the clinker than in the unburnt solid waste except F, Sn, and Hg. Trace element abundances are related to the ash content and composition of the samples. The content of F is negatively correlated with the ash content, while Pb is positively correlated with the ash. The concentrations of As, Mn, Zn, and Cd are highly positively correlated with Fe2O3 in the solid waste. The As content increases with increasing sulfur content in the solid waste. The trace element emissions are calculated for mass balance. The emission factors of trace elements during the spontaneous combustion of the gobs are determined and the trace element concentrations in the flue gas from the spontaneous combustion of solid waste are calculated. More than a half of F, Se, Hg and Pb are released to the atmosphere during spontaneous combustion. Some trace element concentrations in flue gas are higher than the national emission standards. Thus, gob piles from coal mining pose a serious environmental problem. ?? 2007 Elsevier B.V. All rights reserved.

  7. Multidimensional study of the trace elements in the American south western prophyry copper type deposits: mineralogy of uranium

    International Nuclear Information System (INIS)

    Cesbron, Fabien; Drin, Nicolas.

    1981-09-01

    The use of the spark source masse spectrometry and data treatment methods (principal component analysis and discriminent analysis) allow to describe the trace elements comportments in the porphyry copper type deposits of Arizona (USA) and Sonora (Mexico). The chemical elements are studied in relationship with the alteration zones of these deposits. A electronic microprobe study specifies the uranium bearing minerals [fr

  8. A hard tissue cephalometric comparative study between hand tracing and computerized tracing

    Directory of Open Access Journals (Sweden)

    Ramachandra Prabhakar

    2014-01-01

    Full Text Available Aims: To analyze and compare the angular and linear hard tissue cephalometric measurements using hand-tracing and computerized tracings with Nemoceph and Dolphin software systems. Subjects and Methods: A total of 30 cephalograms were randomly chosen for study with the following criteria, cephalograms of patients with good contrast, no distortion, and minimal radiographic artifacts were considered using the digital method (Kodak 8000 C with 12 angular and nine linear parameters selected for the study. Comparisons were determined by post-hoc test using Tukey HSD method. The N-Par tests were performed using Kruskal-Walli′s method. Statistical Analysis Used: ANOVA and post-hoc. Results: The results of this study show that there is no significant difference in the angular and linear measurements recorded. The P values were significant at 0.05 levels for two parameters, Co-A and Co-Gn with the hand-tracing method. This was significant in ANOVA and post-hoc test by Tukey HSD method. Conclusions: This study of comparison provides support for transition from digital hand to computerized tracing methodology. In fact, digital computerized tracings were easier and less time consuming, with the same reliability irrespective of each method of tracing.

  9. Application of trace element analysis to determine trace element concentrations in the field of medicine

    International Nuclear Information System (INIS)

    Kasperek, K.; Feinendegen, L.E.

    1976-01-01

    Applied trace elements research in medicine requires a sensitive and efficient technique of trace elements analysis such as, e.g., neutron activation analysis. Essential trace elements act as stabilisators (iron in haem), structural elements (silicium in fibrous tissue), in hormones (iodine in thyroid hormone), in vitamins (cobalt in vitamin B 12), and in enzymes. Most of the essential trace elements act as coenzymes or in coenzymes or directly as metabolic catalysators. For example, selenium deficiency in PKU and maple syrup patients receiving dietary treatment can be detected by determining the selenium content of the serum, while low selenium values in the whole blood indicate liver cirrhosis. Acrodermatitis enteropathica can be diagnosed by determinig zinc in the serum, and pancreatic insufficiency by determining zinc in the pancreatic juice. Zinc also plays a part in disturbances of growth, in the healing of wounds, and in the insulin metabolism. Cobalt is important in some types of anaemia and in myocardiopathies. Trace elements are also necessary in the treatment of diseases, e.g. iron cobalt in some types of anaemia, and zinc in the delayed healing of wounds in the postoperative phase and in acrodermatitis enteropathica. Chromium is now being tested for the treatment of diabetes mellitus, and fluorides may be of interest in the treatment of osteoporosis. Finally, trace elements are important in the aetiology of acute poisoning, in nutrition, and in environmental protection. (orig./AK) [de

  10. Application of trace element analysis to determine trace element concentrations in the field of medicine. [Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Kasperek, K; Feinendegen, L E

    1976-01-01

    Applied trace elements research in medicine requires a sensitive and efficient technique of trace elements analysis, such as neutron activation analysis. Essential trace elements act as stabilizators (iron in haem), structural elements (silicon in fibrous tissue), in hormones (iodine in thyroid hormone), in vitamins (cobalt in vitamin B 12), and in enzymes. Most of the essential trace elements act as coenzymes or in coenzymes or directly as metabolic catalyzers. For example, selenium deficiency in PKU and maple syrup patients receiving dietary treatment can be detected by determining the selenium content of the serum, while low selenium values in the whole blood indicate liver cirrhosis. Acrodermatitis enteropathica can be diagnosed by determinig zinc in the serum, and pancreatic insufficiency by determining zinc in the pancreatic juice. Zinc also plays a part in disturbances of growth, in the healing of wounds, and in the insulin metabolism. Cobalt is important in some types of anaemia and in myocardiopathies. Trace elements are also necessary in the treatment of diseases, e.g. iron cobalt in some types of anaemia, and zinc in the delayed healing of wounds in the postoperative phase and in acrodermatitis enteropathica. Chromium is now being tested for the treatment of diabetes mellitus, and fluorides may be of interest in the treatment of osteoporosis. Finally, trace elements are important in the aetiology of acute poisoning, in nutrition, and in environmental protection.

  11. Polymer tribology by combining ion implantation and radionuclide tracing

    International Nuclear Information System (INIS)

    Timmers, Heiko; Gladkis, Laura G.; Warner, Jacob A.; Byrne, Aidan P.; Grosso, Mariela F. del; Arbeitman, Claudia R.; Garcia-Bermudez, Gerardo; Geruschke, Thomas; Vianden, Reiner

    2010-01-01

    Radionuclide tracers were ion implanted with three different techniques into the ultra-high molecular weight polyethylene polymer. Tracer nuclei of 7 Be were produced with inverse kinematics via the reaction p( 7 Li, 7 Be)n and caught by polymer samples at a forward scattering angle with a maximum implantation energy of 16 MeV. For the first time, 97 Ru, 100 Pd, and, independently, 111 In have been used as radionuclide tracers in ultra-high molecular weight polyethylene. 97 Ru and 100 Pd were recoil-implanted following the fusion evaporation reactions 92 Zr( 12 C,α3n) 97 Ru and 92 Zr( 12 C,4n) 100 Pd with a maximum implantation energy of 8 MeV. 111 In ions were produced in an ion source, mass-separated and implanted at 160 keV. The tribology of implanted polymer samples was studied by tracing the radionuclide during mechanical wear. Uni-directional and bi-directional sliding apparatus with stainless steel actuators were used. Results suggest a debris exchange process as the characteristic feature of the wear-in phase. This process can establish the steady state required for a subsequently constant wear rate in agreement with Archard's equation. The nano-scale implantation of mass-separated 111 In appears best suited to the study of non-linear tribological processes during wear-in. Such non-linear processes may be expected to be important in micro- and nanomachines.

  12. Life Support Systems: Trace Contaminant and Particulate Control

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Exploration Systems (AES) Life Support Systems project Trace Contaminant and Particulate Control task: Work in the area of trace contamination and...

  13. studies on trace metal concentration pseudotolithus elongatus from ...

    African Journals Online (AJOL)

    DJFLEX

    KEY WORDS: Trace metals, Lead Pollution, Pseudotolithus elongatus, Mbo coastal waters, ..... Analysis of soil heavy metal pollution and ... Pekey, H., Karakas, D., and Bakog'lu, M., 2004. Source apportionment of trace metals in the surface.

  14. Trace Metals Concentration Assessment in Urban Particulate Matter ...

    African Journals Online (AJOL)

    ADOWIE PERE

    Principal component analysis revealed that major sources of trace metals in ambient air ... contributed by earth crust and windblown soil .... Source Apportionment: To probe the origin of trace .... atmospheric accumulation of heavy metals and.

  15. Ben Macdhui High Altitude Trace Gas and Aerosol Transport Experiment

    CSIR Research Space (South Africa)

    Piketh, SJ

    1999-01-01

    Full Text Available The Ben Macdhui High Altitude Aerosol and Trace Gas Transport Experiment (BHATTEX) was started to characterize the nature and magnitude of atmospheric, aerosol and trace gas transport paths recirculation over and exiting from southern Africa...

  16. Commuting quantum traces: the case of reflection algebras

    Energy Technology Data Exchange (ETDEWEB)

    Avan, Jean [Laboratory of Theoretical Physics and Modelization, University of Cergy, 5 mail Gay-Lussac, Neuville-sur-Oise, F-95031, Cergy-Pontoise Cedex (France); Doikou, Anastasia [Theoretical Physics Laboratory of Annecy-Le-Vieux, LAPTH, BP 110, Annecy-Le-Vieux, F-74941 (France)

    2004-02-06

    We formulate a systematic construction of commuting quantum traces for reflection algebras. This is achieved by introducing two dual sets of generalized reflection equations with associated consistent fusion procedures. Products of their respective solutions yield commuting quantum traces.

  17. Liquid phase microextraction for the analysis of trace elements and their speciation

    International Nuclear Information System (INIS)

    Hu, Bin; He, Man; Chen, Beibei; Xia, Linbo

    2013-01-01

    Trace/ultra-trace elements and their speciation analysis in complex matrices usually require sample preparation procedures to achieve sample clean-up and analyte preconcentration. Sample preparation is often the bottleneck in trace elements and their speciation analysis which has a direct impact on accuracy, precision and limits of detection and is often the rate-determining step of the analytical process. Recent trends in sample preparation include miniaturization, automation, high-throughput performance and reduction in solvent/sample consumption and operation time. Liquid-phase microextraction (LPME) technique as a novel and promising alternative in sample preparation can meet these requirements and has become a very efficient sample preparation technique. This review updates the state of art of LPME for trace elements and their speciation analysis and discusses its promising prospects. The major thrust of the article highlights the applications of LPME including single-drop microextraction (SDME), hollow fiber-liquid phase microextraction (HF-LPME), dispersive liquid liquid microextraction (DLLME) and solidified floating organic drop microextraction (SFODME) to the fields of elemental and their speciation analysis by atomic spectrometry-based methods, especially inductively coupled plasma mass spectrometry. General and specific concepts, different extraction formats and characteristics of LPME are described and compared, along with examples of recent innovations and applications presented to demonstrate its potential for trace elements and their speciation analysis in biological and environmental fields. Moreover, the application potential and an outlook on the combination of LPME and atomic spectrometry-based techniques for inorganic analysis are commentated. - Highlights: • The state of art of LPME for trace elements and their speciation analysis is updated. • Different extraction formats of LPME are described. • The application potential and future

  18. The effect of pasteurization on trace elements in donor breast milk.

    Science.gov (United States)

    Mohd-Taufek, N; Cartwright, D; Davies, M; Hewavitharana, A K; Koorts, P; McConachy, H; Shaw, P N; Sumner, R; Whitfield, K

    2016-10-01

    Premature infants often receive pasteurized donor human milk when mothers are unable to provide their own milk. This study aims to establish the effect of the pasteurization process on a range of trace elements in donor milk. Breast milk was collected from 16 mothers donating to the milk bank at the Royal Brisbane and Women's Hospital. Samples were divided into pre- and post-pasteurization aliquots and were Holder pasteurized. Inductively coupled plasma mass spectrometry was used to analyze the trace elements zinc (Zn), copper (Cu), selenium (Se), manganese (Mn), iodine (I), iron (Fe), molybdenum (Mo) and bromine (Br). Differences in trace elements pre- and post-pasteurization were analyzed. No significant differences were found between the trace elements tested pre- and post-pasteurization, except for Fe (Ppasteurization aliquots were-Zn: 1639 (888-4508), 1743 (878-4143), Cu: 360 (258-571), 367 (253-531), Se: 12.34 (11.73-17.60), 12.62 (11.94-16.64), Mn: (1.48 (1.01-1.75), 1.49 (1.11-1.75), I (153 (94-189), 158 (93-183), Fe (211 (171-277), 194 (153-253), Mo (1.46 (0.37-2.99), 1.42 (0.29-3.73) and Br (1066 (834-1443), 989 (902-1396). Pasteurization had minimal effect on several trace elements in donor breast milk but high levels of inter-donor variability of trace elements were observed. The observed decrease in the iron content of pasteurized donor milk is, however, unlikely to be clinically relevant.

  19. Process modeling for Humanities: tracing and analyzing scientific processes

    OpenAIRE

    Hug , Charlotte; Salinesi , Camille; Deneckere , Rebecca; Lamasse , Stéphane

    2011-01-01

    International audience; This paper concerns epistemology and the understanding of research processes in Humanities, such as Archaeology. We believe that to properly understand research processes, it is essential to trace them. The collected traces depend on the process model established, which has to be as accurate as possible to exhaustively record the traces. In this paper, we briefly explain why the existing process models for Humanities are not sufficient to represent traces. We then pres...

  20. The determination of trace elements in uranium ores by x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    De Villiers, W. van Z.

    1983-11-01

    The determination of 17 trace elements (As, Ba, Co, Cr, Cu, Mo, Nb, Ni, Pb, Rb, Sr, Th, U, V, Y, Zn and Zr) in uranium ores by x-ray fluorescence spectrometry was investigated in this study. The determination of major elements was also necessary for the calculation of mass absorption coefficients. Initially a method was developed for the determination of the elements of interest in unmineralised silicates. Correction for absorption of radiation by the sample were made by means of mass absorption coefficients which were obtained from the relation between the inverse of the mass absorption coefficient and the intensity of the Compton scattering peak. The Feather and Willis method was used for determining the background intensity at the peak positions as well as for mass absorption coefficients. It was observed that the background intensity in the region of the uranium lines increases with increasing uranium content of the sample

  1. Trace element distribution in geological crystals

    Energy Technology Data Exchange (ETDEWEB)

    Den Besten, J L; Jamieson, D N; Weiser, P S [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    Channelling is a useful microprobe technique for determining the structure of crystals, but until now has not been performed on geological crystals. The composition has been investigated rather than the structure, which can further explain the origin of the crystal and provide useful information on the substitutionality of trace elements. This may then lead to applications of extraction of valuable metals and semiconductor electronics. Natural crystals of pyrite, FeS{sub 2}, which contains a substantial concentration of gold were channeled and examined to identify the channel axis orientation. Rutherford Backscattering (RBS) and Particle Induced X-Ray Emission (PIXE) spectra using MeV ions were obtained in the experiment to provide a comparison of lattice and non-lattice trace elements. 3 figs.

  2. Trace element distribution in geological crystals

    Energy Technology Data Exchange (ETDEWEB)

    Den Besten, J.L.; Jamieson, D.N.; Weiser, P.S. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Channelling is a useful microprobe technique for determining the structure of crystals, but until now has not been performed on geological crystals. The composition has been investigated rather than the structure, which can further explain the origin of the crystal and provide useful information on the substitutionality of trace elements. This may then lead to applications of extraction of valuable metals and semiconductor electronics. Natural crystals of pyrite, FeS{sub 2}, which contains a substantial concentration of gold were channeled and examined to identify the channel axis orientation. Rutherford Backscattering (RBS) and Particle Induced X-Ray Emission (PIXE) spectra using MeV ions were obtained in the experiment to provide a comparison of lattice and non-lattice trace elements. 3 figs.

  3. NSF-RANN Trace Contaminants Program directory

    International Nuclear Information System (INIS)

    Purnell, P.A.; Smith, S.K.; Wilkes, C.F.

    1976-10-01

    This directory is designed to aid effective communication throughout the National Science Foundation's Trace Contaminants Program, Research Applied to National Needs. The majority of the participants in the Program are represented by name, address, telephone number, and a very brief description of research interest. The directory has five major divisions to facilitate its use. Section I contains a listing of the program managers associated with the NSF-RANN Trace Contaminants Program. Section II lists the principal investigators, co-principal investigators, and coordinators of each of the research grants in the Program. Section III lists the personnel by individual projects. Section IV contains a total alphabetic listing complete with project titles and Section V contains a keyword index. This directory is maintained by the Toxic Materials Information Center as part of the Environmental Resource Center of the Information Center Complex, Information Division, Oak Ridge National Laboratory

  4. Holographic models and the QCD trace anomaly

    International Nuclear Information System (INIS)

    Goity, Jose L.; Trinchero, Roberto C.

    2012-01-01

    Five dimensional dilaton models are considered as possible holographic duals of the pure gauge QCD vacuum. In the framework of these models, the QCD trace anomaly equation is considered. Each quantity appearing in that equation is computed by holographic means. Two exact solutions for different dilaton potentials corresponding to perturbative and non-perturbative β-functions are studied. It is shown that in the perturbative case, where the β-function is the QCD one at leading order, the resulting space is not asymptotically AdS. In the non-perturbative case, the model considered presents confinement of static quarks and leads to a non-vanishing gluon condensate, although it does not correspond to an asymptotically free theory. In both cases analyses based on the trace anomaly and on Wilson loops are carried out.

  5. Trace metal fronts in European shelf waters

    International Nuclear Information System (INIS)

    Kremling, K.

    1983-01-01

    The Hebrides shelf edge area is characterized by strong horizontal salinity gradients (fronts) which mark the boundary between Scottish coastal and oceanic waters. The results presented here, obtained in summer 1981 on a transect between the open north Atlantic and the German Bight, confirm that the hydrographical front is accompanied by dramatic increases in inorganic nutrients (phosphate, silicate) and dissolved trace elements such as Cd, Cu, Mn, and 226 Ra. These data (together with measurements from North Sea regions) suggest that the trace metals are mobilized from partly reduced (organic-rich) sediments and vertically mixed into the surface waters. The regional variations evident from the transect are interpreted as being the result of the hydrography prevailing in waters around the British Isles. (author)

  6. Polarographic determination of trace amounts of thorium

    Energy Technology Data Exchange (ETDEWEB)

    Zaofan Zhao; Xiaohua Cai; Peibiao Li; Handong Yang

    1986-07-01

    A sensitive linear-sweep polarographic method for the determination of thorium is described. It is based on the thorium complex with Xylidyl Blue I (XBI) in a medium containing ethylenediamine, 1, 10-phenanthroline, oxalic acid and ninhydrin, at pH 10.5-11.5. The complex has been proved to be Th(XBI)/sub 2/, with log ..beta..'=9.6. The method can be used to determine trace amounts of thorium over the range 3.5x10/sup -8/-3x10/sup -6/M. The detection limit is 1x10/sup -8/M. A solvent extraction procedure is necessary to eliminate interference from several cations. The method has been applied to determination of traces of thorium in minerals, with good results.

  7. Hierarchical Traces for Reduced NSM Memory Requirements

    Science.gov (United States)

    Dahl, Torbjørn S.

    This paper presents work on using hierarchical long term memory to reduce the memory requirements of nearest sequence memory (NSM) learning, a previously published, instance-based reinforcement learning algorithm. A hierarchical memory representation reduces the memory requirements by allowing traces to share common sub-sequences. We present moderated mechanisms for estimating discounted future rewards and for dealing with hidden state using hierarchical memory. We also present an experimental analysis of how the sub-sequence length affects the memory compression achieved and show that the reduced memory requirements do not effect the speed of learning. Finally, we analyse and discuss the persistence of the sub-sequences independent of specific trace instances.

  8. On Newton-Cartan trace anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Auzzi, Roberto [Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore,Via Musei 41, 25121 Brescia (Italy); INFN Sezione di Perugia,Via A. Pascoli, 06123 Perugia (Italy); Baiguera, Stefano [Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore,Via Musei 41, 25121 Brescia (Italy); Nardelli, Giuseppe [Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore,Via Musei 41, 25121 Brescia (Italy); TIFPA - INFN, c/o Dipartimento di Fisica, Università di Trento,38123 Povo (Italy)

    2016-02-01

    We classify the trace anomaly for parity-invariant non-relativistic Schrödinger theories in 2+1 dimensions coupled to background Newton-Cartan gravity. The general anomaly structure looks very different from the one in the z=2 Lifshitz theories. The type A content of the anomaly is remarkably identical to that of the relativistic 3+1 dimensional case, suggesting the conjecture that an a-theorem should exist also in the Newton-Cartan context.

  9. Trace elements and protein in human milk

    International Nuclear Information System (INIS)

    Abusamra, Y.I.H.

    1995-01-01

    The trace elements Zn, Fe, Cu, Mn, Ni and Pb and some related major elements which are Ca, Cl K and total protein contents of human samples from ninety mothers were examined in this study. Samples were collected from Khartoum, Khartoum North and Omdurman, from the second day of delivery up to the third month where the milk reaches a relatively stable levels. These samples representing different stages of lactation which are colostrum ( 1-3 days ), tranitional ( up to 14 days ) and mature milk. The principle aim of this study is to measure the trace elements and protein contents in relation to stage of lactation and to compare with the literature. Atomic absorption spectroscopy and X-ray fluorescence were used to measure trace elements in the samples. The methods were found to be quite reliable as proved by the analysis of the standard reference material HM-1. Whereas neutron activation analysis was used for measurements of total protein. Colostrum was found to have the highest amounts of trace elements and protein. Fe mean concentration was 273 g/dm 3 at colostrum stage and it decreased to 146 g/dm 3 in mature milk ( 49% ). Zn decreased from 6000 g/dm 3 in colostrum to 1300 g/dm 3 in mature stage ( 78% ). Mn was 12g/dm 3 in colostrum, and it decreased to 2.9 g/dm 3 in mature milk ( 75% ). Cu decreased from 370 g/dm 3 to 117 g/dm 3 ( 68% ). Ni decreased from 24 g/dm 3 to 8.8 g/dm 3 ( 63% ) and Pb from 12 g/dm 3 to 2.6 g/dm 3 ( 76% ). Total protein was 37.3% of the dry milk in colostrum and it was 12.2% in mature milk. (author). 75 refs., 25 tabs., 30 figs

  10. On Newton-Cartan trace anomalies

    International Nuclear Information System (INIS)

    Auzzi, Roberto; Baiguera, Stefano; Nardelli, Giuseppe

    2016-01-01

    We classify the trace anomaly for parity-invariant non-relativistic Schrödinger theories in 2+1 dimensions coupled to background Newton-Cartan gravity. The general anomaly structure looks very different from the one in the z=2 Lifshitz theories. The type A content of the anomaly is remarkably identical to that of the relativistic 3+1 dimensional case, suggesting the conjecture that an a-theorem should exist also in the Newton-Cartan context.

  11. Cytocompatible cellulose hydrogels containing trace lignin

    International Nuclear Information System (INIS)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-01-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12 h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43 N/mm"2 and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

  12. Assessment of trace element stabilization in soil

    OpenAIRE

    Kumpiene, Jurate

    2005-01-01

    The thesis deals with the remediation of trace element contaminated soil by the chemical stabilization technique. The objective is to complement the knowledge about possibilities of applying the stabilization either (1) as an alternate soil remediation method to excavation and landfilling or (2) for a pre-treatment of contaminated soil before landfilling. The work is based on two case studies of the stabilization of 1) Cr, Cu, As, and Zn contaminated soil using metallic iron and 2) Pb and Cu ...

  13. METHOD OF CONJUGATED CIRCULAR ARCS TRACING

    Directory of Open Access Journals (Sweden)

    N. Ageyev Vladimir

    2017-01-01

    Full Text Available The geometric properties of conjugated circular arcs connecting two points on the plane with set directions of tan- gent vectors are studied in the work. It is shown that pairs of conjugated circular arcs with the same conditions in frontier points create one-parameter set of smooth curves tightly filling all the plane. One of the basic properties of this set is the fact that all coupling points of circular arcs are on the circular curve going through the initially given points. The circle radius depends on the direction of tangent vectors. Any point of the circle curve, named auxiliary in this work, determines a pair of conjugated arcs with given boundary conditions. One more condition of the auxiliary circle curve is that it divides the plane into two parts. The arcs going from the initial point are out of the circle limited by this circle curve and the arcs coming to the final point are inside it. These properties are the basis for the method of conjugated circular arcs tracing pro- posed in this article. The algorithm is rather simple and allows to fulfill all the needed plottings using only the divider and ruler. Two concrete examples are considered. The first one is related to the problem of tracing of a pair of conjugated arcs with the minimal curve jump when going through the coupling point. The second one demonstrates the possibility of trac- ing of the smooth curve going through any three points on the plane under condition that in the initial and final points the directions of tangent vectors are given. The proposed methods of conjugated circular arcs tracing can be applied in solving of a wide variety of problems connected with the tracing of cam contours, for example pattern curves in textile industry or in computer-aided-design systems when programming of looms with numeric control.

  14. Cytocompatible cellulose hydrogels containing trace lignin

    Energy Technology Data Exchange (ETDEWEB)

    Nakasone, Kazuki; Kobayashi, Takaomi, E-mail: takaomi@nagaoakut.ac.jp

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12 h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43 N/mm{sup 2} and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

  15. The Combinatorial Trace Method in Action

    Science.gov (United States)

    Krebs, Mike; Martinez, Natalie C.

    2013-01-01

    On any finite graph, the number of closed walks of length k is equal to the sum of the kth powers of the eigenvalues of any adjacency matrix. This simple observation is the basis for the combinatorial trace method, wherein we attempt to count (or bound) the number of closed walks of a given length so as to obtain information about the graph's…

  16. Trace-element analysis in environmental sciences

    International Nuclear Information System (INIS)

    Valkovic, V.; Moschini, G.

    1988-01-01

    The use of charged-particle accelerators in trace-element analysis in the field of environmental sciences is described in this article. Nuclear reactions, charged-particle-induced X-ray emission as well as other nuclear and atomic processes can be used individually, or combined, in developing adequate analytical systems. In addition to concentration levels, concentration levels, concentration profiles can be measured, resulting in unique information. Some examples of experiments performed are described together with the suggestions for future measurements [pt

  17. Scandium - problem of ultra-trace-element essentiality

    International Nuclear Information System (INIS)

    Kist, A.A.; Zkuk, L.I.; Danilova, E.A.; Makhmudov, E.A.

    2006-01-01

    Full text: Role of constitutional and essential elements in Life is known quite well. It is also well known that all chemical elements present in the living matter. Nevertheless essentiality of at least 55 chemical elements (more than a half of number of natural elements) is still not accepted. In many cases these elements presumably play important role in the Life. On the other hand their essentiality is still under doubt. One of the 'strange' elements in this connection is scandium. Scandium is an element which is very 'simple' for instrumental neutron activation analysis (INAA). For many years in our laboratory were carried out studies on animals and human tissues and fluids elemental composition using INAA in which data for scandium were obtained as 'redundant' information. Essentiality of scandium was newer proven using accepted criteria of elements. Nevertheless in our studies were found various regularities, statistically significant inter-elemental correlations and correlations between elements in tissues and fluids versus clinic and biochemical data. There are some examples. There were found correlations of scandium hair concentration and blood glucose (r=0.68±0.13), body mass index (r=0.86±0.07), leukocyte with phagocytic activity migration inhibition test (r=0.68±0.18), size of cavity of the left heart auricle (r=-0.65±0.16), final systolic bulk (r=0.80±0.12), stroke output of heart (r=-0.79±0.12), final diastolic bulk (0.88±0.0080) etc. In addition using gel filtration in rat liver cytosol was found peak of scandium in elution curve. Examples and correlations given in the paper say in favor that scandium may play quite important role in biological processes and that the biological role of scandium should be studied more intensive. The most important criterion is an appearance of the organism dysfunction in case of removal of the studied elements from the diet (intake) which in all other sides remains completely valuable and disappearance of all

  18. Inorganic and organic trace mineral supplementation in weanling pig diets

    Directory of Open Access Journals (Sweden)

    MARIA C. THOMAZ

    2015-06-01

    Full Text Available A study was conducted to evaluate the effects of dietary inorganic and organic trace minerals in two levels of supplementation regarding performance, diarrhea occurrence, hematological parameters, fecal mineral excretion and mineral retention in metacarpals and liver of weanling pigs. Seventy piglets weaned at 21 days of age with an average initial body weight of 6.70 ± 0.38 kg were allotted in five treatments: control diet (no added trace mineral premix; 50% ITMP (control diet with inorganic trace mineral premix supplying only 50% of trace mineral requirements; 50% OTMP (control diet with organic trace mineral premix supplying only 50% of trace mineral requirements; 100% ITMP (control diet with inorganic trace mineral premix supplying 100% of trace mineral requirements; and 100% OTMP (control diet with organic trace mineral premix supplying 100% of trace mineral requirements. Feed intake and daily weight gain were not affected by treatments, however, piglets supplemented by trace minerals presented better gain:feed ratio. No differences were observed at calcium, phosphorus, potassium, magnesium, sodium and sulfur excreted in feces per kilogram of feed intake. Treatments did not affect calcium, phosphorus, magnesium, sulfur and iron content in metacarpals. Trace mineral supplementation, regardless of level and source, improved the performance of piglets.

  19. A remote tracing facility for distributed systems

    International Nuclear Information System (INIS)

    Ehm, F.; Dworak, A.

    2012-01-01

    Today, CERN's control system is built upon a large number of C++ and Java services producing log events. In such a largely distributed environment these log messages are essential for problem recognition and tracing. Tracing is therefore vital for operation as understanding an issue in a subsystem means analysing log events in an efficient and fast manner. At present 3150 device servers are deployed on 1600 disk-less front-ends and they send their log messages via the network to an in-house developed central server which, in turn, saves them to files. However, this solution is not able to provide several highly desired features and has performance limitations which led to the development of a new solution. The new distributed tracing facility fulfills these requirements by taking advantage of the Streaming Text Oriented Messaging Protocol (STOMP) and ActiveMQ as the transport layer. The system not only allows storing critical log events centrally in files or in a database but also allows other clients (e.g. graphical interfaces) to read the same events concurrently by using the provided Java API. Thanks to the ActiveMQ broker technology the system can easily be extended to clients implemented in other languages and it is highly scalable in terms of performance. Long running tests have shown that the system can handle up to 10.000 messages/second. (authors)

  20. The Relevant Physical Trace in Criminal Investigation

    Directory of Open Access Journals (Sweden)

    Durdica Hazard

    2016-01-01

    Full Text Available A criminal investigation requires the forensic scientist to search and to interpret vestiges of a criminal act that happened in the past. The forensic scientist is one of the many stakeholders who take part in the information quest within the criminal justice system. She reads the investigation scene in search of physical traces that should enable her to tell the story of the offense/crime that allegedly occurred. The challenge for any investigator is to detect and recognize relevant physical traces in order to provide clues for investigation and intelligence purposes, and that will constitute sound and relevant evidence for the court. This article shows how important it is to consider the relevancy of physical traces from the beginning of the investigation and what might influence the evaluation process. The exchange and management of information between the investigation stakeholders are important. Relevancy is a dimension that needs to be understood from the standpoints of law enforcement personnel and forensic scientists with the aim of strengthening investigation and ultimately the overall judicial process.