WorldWideScience

Sample records for absorption spectrometric detection

  1. [Determination of trace cobalt in human urine by graphite furnace atomic absorption spectrometr].

    Science.gov (United States)

    Zhong, L X; Ding, B M; Jiang, D; Liu, D Y; Yu, B; Zhu, B L; Ding, L

    2016-05-20

    To establish a method to determine cobalt in human urine by graphite furnace atomic absorption spectrometry. Urine with 2% nitric acid diluted two-fold, to quantify the curve, graphite furnace atomic absorption spectrometric detection. Co was linear within 2.5~40.0 ng/ml with r>0.999. Spike experiment showed that Co received good recovery rate, which was 90.8%~94.8%. Intra-assay precisions were 3.2%~5.1% for Co, inter-assay precisions were 4.4%~5.2% for Co. The method by using graphite furnace atomic absorption spectrometr to determine urine Co was fast, accurate and with low matrix effect. It could meet the requirement in GBZ/T 210.5-2008.

  2. Novel atomic absorption spectrometric and rapid spectrophotometric methods for the quantitation of paracetamol in saliva: application to pharmacokinetic studies.

    Science.gov (United States)

    Issa, M M; Nejem, R M; El-Abadla, N S; Al-Kholy, M; Saleh, Akila A

    2008-01-01

    A novel atomic absorption spectrometric method and two highly sensitive spectrophotometric methods were developed for the determination of paracetamol. These techniques based on the oxidation of paracetamol by iron (III) (method I); oxidation of p-aminophenol after the hydrolysis of paracetamol (method II). Iron (II) then reacts with potassium ferricyanide to form Prussian blue color with a maximum absorbance at 700 nm. The atomic absorption method was accomplished by extracting the excess iron (III) in method II and aspirates the aqueous layer into air-acetylene flame to measure the absorbance of iron (II) at 302.1 nm. The reactions have been spectrometrically evaluated to attain optimum experimental conditions. Linear responses were exhibited over the ranges 1.0-10, 0.2-2.0 and 0.1-1.0 mug/ml for method I, method II and atomic absorption spectrometric method, respectively. A high sensitivity is recorded for the proposed methods I and II and atomic absorption spectrometric method value indicate: 0.05, 0.022 and 0.012 mug/ml, respectively. The limit of quantitation of paracetamol by method II and atomic absorption spectrometric method were 0.20 and 0.10 mug/ml. Method II and the atomic absorption spectrometric method were applied to demonstrate a pharmacokinetic study by means of salivary samples in normal volunteers who received 1.0 g paracetamol. Intra and inter-day precision did not exceed 6.9%.

  3. Column preconcentration and electrothermal atomic absorption spectrometric determination of rhodium in some food and standard samples.

    Science.gov (United States)

    Taher, Mohammad Ali; Pourmohammad, Fatemeh; Fazelirad, Hamid

    2015-12-01

    In the present work, an electrothermal atomic absorption spectrometric method has been developed for the determination of ultra-trace amounts of rhodium after adsorption of its 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol/tetraphenylborate ion associated complex at the surface of alumina. Several factors affecting the extraction efficiency such as the pH, type of eluent, sample and eluent flow rates, sorption capacity of alumina and sample volume were investigated and optimized. The relative standard deviation for eight measurements of 0.1 ng/mL of rhodium was ±6.3%. In this method, the detection limit was 0.003 ng/mL in the original solution. The sorption capacity of alumina and the linear range for Rh(III) were evaluated as 0.8 mg/g and 0.015-0.45 ng/mL in the original solution, respectively. The proposed method was successfully applied for the extraction and determination of rhodium content in some food and standard samples with high recovery values. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Study of non-validity of mixture rule near K-absorption edges by X-ray spectrometric technique

    International Nuclear Information System (INIS)

    Sharanabasappa; Chitralekha, A.; Kerur, B.R.; Anilkumar, S.

    2012-01-01

    X-ray spectrometric technique has been described to determine the X-ray mass attenuation coefficient, μ/ρ, of X-rays employing HPGe X-ray detector and radioactive sources. The photon intensity is measured by gating the channel of the spectrometer at FWHM/photo peak. Using the technique the 'best value' values of μ/ρ were obtained for those thicknesses which lie in the transmission (T) range 0.5 ≥ T ≥ 0.02. Total attenuation cross sections for other elements and lead compounds were measured at photon energies from 17 to 88 keV to study the Bragg's additivity law near the absorption edge of the lead. The measured values of mass attenuation coefficient values are compared with theoretical values obtained using Winxcom (programme). This study suggests that measured mass attenuation coefficient values at and near absorption edges differ from the theoretical value by about 17-23%. (author)

  5. Atomic absorption spectrometric determination of copper, zinc, and lead in geological materials

    Science.gov (United States)

    Sanzolone, R.F.; Chao, T.T.

    1976-01-01

    An atomic absorption spectrometric method is described for the determination of copper, zinc, and lead in geological materials. The sample is digested with HF-HCl-H2O2; the final solution for analysis is in 10 % (v/v) HCl. Copper and zinc are determined directly by aspirating the solution into an air-acetylene flame. A separate aliquot of the solution is used for determination of lead; lead is extracted into TOPO-MIBK from the acidic solution in the presence of iodide and ascorbic acid. For a 0.50-g sample, the limits of determination are 10-2000 p.p.m. for Cu and Zn, and 5-5000 p.p.m. for Pb. As much as 40 % Fe or Ca. and 10 % Al, Mg, or Mn in the sample do not interfere. The proposed method can be applied to the determination of copper, zinc, and lead in a wide range of geological materials including iron- and manganese-rich, calcareous and carbonate samples. ?? 1976.

  6. Automated sequential injection-microcolumn approach with on-line flame atomic absorption spectrometric detection for implementing metal fractionation schemes of homogeneous and non-homogeneous solid samples of environmental interest

    DEFF Research Database (Denmark)

    Chomchoei, Roongrat; Miró, Manuel; Hansen, Elo Harald

    2005-01-01

    spectrometric detection and used for the determination of Cu as a model analyte, the potentials of this novel hyphenated approach are demonstrated by the ability of handling up to 300 mg sample of a nonhomogeneous sewage amended soil (viz., CRM 483). The three steps of the endorsed Standards, Measurements...

  7. Mass spectrometric detection of siRNA in plasma samples for doping control purposes.

    Science.gov (United States)

    Kohler, Maxie; Thomas, Andreas; Walpurgis, Katja; Schänzer, Wilhelm; Thevis, Mario

    2010-10-01

    Small interfering ribonucleic acid (siRNA) molecules can effect the expression of any gene by inducing the degradation of mRNA. Therefore, these molecules can be of interest for illicit performance enhancement in sports by affecting different metabolic pathways. An example of an efficient performance-enhancing gene knockdown is the myostatin gene that regulates muscle growth. This study was carried out to provide a tool for the mass spectrometric detection of modified and unmodified siRNA from plasma samples. The oligonucleotides are purified by centrifugal filtration and the use of an miRNA purification kit, followed by flow-injection analysis using an Exactive mass spectrometer to yield the accurate masses of the sense and antisense strands. Although chromatography and sensitive mass spectrometric analysis of oligonucleotides are still challenging, a method was developed and validated that has adequate sensitivity (limit of detection 0.25-1 nmol mL(-1)) and performance (precision 11-21%, recovery 23-67%) for typical antisense oligonucleotides currently used in clinical studies.

  8. Speciation and detection of arsenic in aqueous samples: A review of recent progress in non-atomic spectrometric methods

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jian [State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen 361102 (China); Department of Chemistry and Biochemistry, University of Texas, 700 Planetarium Place, Arlington, TX 76019 (United States); Sengupta, Mrinal K. [Department of Chemistry and Biochemistry, University of Texas, 700 Planetarium Place, Arlington, TX 76019 (United States); Thermo Fisher Scientific, Dionex Products, 445 Lakeside Drive, Sunnyvale, CA, 94085 (United States); Yuan, Dongxing [State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen 361102 (China); Dasgupta, Purnendu K., E-mail: Dasgupta@uta.edu [Department of Chemistry and Biochemistry, University of Texas, 700 Planetarium Place, Arlington, TX 76019 (United States)

    2014-06-01

    Highlights: • Compilation of principal official documents and major review articles, including the toxicology and chemistry of As. • Review of non-atomic spectrometric methods for speciation and detection of arsenic in aqueous samples (2005–2013) of the performance of field-usable methods. - Abstract: Inorganic arsenic (As) displays extreme toxicity and is a class A human carcinogen. It is of interest to both analytical chemists and environmental scientists. Facile and sensitive determination of As and knowledge of the speciation of forms of As in aqueous samples are vitally important. Nearly every nation has relevant official regulations on permissible limits of drinking water As content. The size of the literature on As is therefore formidable. The heart of this review consists of two tables: one is a compilation of principal official documents and major review articles, including the toxicology and chemistry of As. This includes comprehensive official compendia on As speciation, sample treatment, recommended procedures for the determination of As in specific sample matrices with specific analytical instrument(s), procedures for multi-element (including As) speciation and analysis, and prior comprehensive reviews on arsenic analysis. The second table focuses on the recent literature (2005–2013, the coverage for 2013 is incomplete) on As measurement in aqueous matrices. Recent As speciation and analysis methods based on spectrometric and electrochemical methods, inductively coupled plasma-mass spectrometry, neutron activation analysis and biosensors are summarized. We have deliberately excluded atomic optical spectrometric techniques (atomic absorption, atomic fluorescence, inductively coupled plasma-optical emission spectrometry) not because they are not important (in fact the majority of arsenic determinations are possibly carried out by one of these techniques) but because these methods are sufficiently mature and little meaningful innovation has been

  9. Speciation and detection of arsenic in aqueous samples: A review of recent progress in non-atomic spectrometric methods

    International Nuclear Information System (INIS)

    Ma, Jian; Sengupta, Mrinal K.; Yuan, Dongxing; Dasgupta, Purnendu K.

    2014-01-01

    Highlights: • Compilation of principal official documents and major review articles, including the toxicology and chemistry of As. • Review of non-atomic spectrometric methods for speciation and detection of arsenic in aqueous samples (2005–2013) of the performance of field-usable methods. - Abstract: Inorganic arsenic (As) displays extreme toxicity and is a class A human carcinogen. It is of interest to both analytical chemists and environmental scientists. Facile and sensitive determination of As and knowledge of the speciation of forms of As in aqueous samples are vitally important. Nearly every nation has relevant official regulations on permissible limits of drinking water As content. The size of the literature on As is therefore formidable. The heart of this review consists of two tables: one is a compilation of principal official documents and major review articles, including the toxicology and chemistry of As. This includes comprehensive official compendia on As speciation, sample treatment, recommended procedures for the determination of As in specific sample matrices with specific analytical instrument(s), procedures for multi-element (including As) speciation and analysis, and prior comprehensive reviews on arsenic analysis. The second table focuses on the recent literature (2005–2013, the coverage for 2013 is incomplete) on As measurement in aqueous matrices. Recent As speciation and analysis methods based on spectrometric and electrochemical methods, inductively coupled plasma-mass spectrometry, neutron activation analysis and biosensors are summarized. We have deliberately excluded atomic optical spectrometric techniques (atomic absorption, atomic fluorescence, inductively coupled plasma-optical emission spectrometry) not because they are not important (in fact the majority of arsenic determinations are possibly carried out by one of these techniques) but because these methods are sufficiently mature and little meaningful innovation has been

  10. Status of mass spectrometric radiocarbon detection at ETHZ

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, Martin; Maxeiner, Sascha; Wacker, Lukas; Synal, Hans-Arno

    2015-10-15

    A prototype of a mass spectrometric radiocarbon detection instrument without accelerator stage was built for the first time and set into operation at ETH Zurich. The system is designed as an experimental platform to optimize performance of {sup 14}C detection at low ion energies and to study the most relevant processes that may limit system performance. The optimized stripper unit incorporates differential pumping to maintain a low gas outflow and a revised tube design to better match the phase space volume of the ion beam at low energies. The system is fully operational and has demonstrated true radiocarbon dating capabilities. The overall beam transmission through the stripper tube is about 40% for the 1{sup +} charge state. Radiocarbon analyses with an overall precision of 0.6% were obtained on a single sample under regular measurement conditions. By analyzing multiple targets of the same sample material an uncertainty level of 0.3% has been reached. The background level corresponds to a radiocarbon age of 40,000 years.

  11. Atomic absorption spectrometric determination of mineral elements in mammalian bones

    International Nuclear Information System (INIS)

    Udoh, Anthony P.

    2000-01-01

    The phosphorus content of the major bones of male and female selected mammals was determined using the yellow vanadomolybdate colorimetric method. For each animal, the bone with the highest phosphorus content was used as pilot sample. Varying concentrations of strontium were added to solutions of the ashed pilot samples to minimize phosphorus interference in the determination of calcium and magnesium using flame atomic absorption spectrophotometry operated on the air-acetylene mode. At least 6,000 ppm (0.6%) of strontium was required to give optimum results for calcium. The amount of magnesium obtained from the analysis was not affected by the addition of strontium. With the incorporation of strontium in the sample solution, all elements of interest can be determined in the same sample solution. Based on this, a procedure is proposed for the determination of calcium and other elements in bones. Average recoveries of spiked calcium and magnesium were 97.85% and 98.16%, respectively at the 95% confidence level. The coefficients of variation obtained for replicate determinations using one of the samples were 0.00% for calcium, lead and sodium, 2.93% for magnesium, 3.27% for iron and 3.92% for zinc at the concentration levels found in that sample. Results from the proposed procedure compared well with those from classical chemical methods at the 95% confidence level. It is evident that calcium phosphorus, magnesium and sodium which are the most abundant elements in the bones are distributed in varying amounts both in the different types of bones and different animal species, although the general trend is Ca > P > Na > Mg for each bone considered. The calcium - phosphorus ratio is generally 3:1. The work set out to propose an atomic absorption spectrometric method for the multi-element analysis of mammalian bones with a single sample preparation and to study the distribution pattern of these elements in the bones. (Author)

  12. Retrospective detection of exposure to organophosphorus anti-cholinesterases: Mass spectrometric analysis of phosphylated human butyrylcholinesterase

    NARCIS (Netherlands)

    Fidder, A.; Hulst, A.G.; Noort, D.; Ruiter, R. de; Schans, M.J. van der; Benschop, H.P.; Langenberg, J.P.

    2002-01-01

    In this paper a novel and general procedure is presented for detection of organophosphate-inhibited human butyrylcholinesterase (HuBuChE), which is based on electrospray tandem mass spectrometric analysis of phosphylated nonapeptides obtained after pepsin digestion of the enzyme. The utility of this

  13. Separation/preconcentration of silver(I) and lead(II) in environmental samples on cellulose nitrate membrane filter prior to their flame atomic absorption spectrometric determinations

    International Nuclear Information System (INIS)

    Soylak, Mustafa; Cay, Rukiye Sungur

    2007-01-01

    An enrichment method for trace amounts of Ag(I) and Pb(II) has been established prior to their flame atomic absorption spectrometric determinations. The preconcentration/separation procedure is based on chelate formation of Ag(I) and Pb(II) with ammonium pyrrolidine dithiocarbamate (APDC) and on retention of the chelates on cellulose nitrate membrane filter. The influences of some analytical parameters including pH and amounts of reagent, etc. on the recoveries of analytes were investigated. The effects of interferic ions on the quantitative recoveries of analytes were also examined. The detection limits (k = 3, N = 11) were 4.6 μg L -1 for silver(I) and 15.3 μg L -1 for lead(II). The relative standard deviations (R.S.D.) of the determinations for analyte ions were below 3%. The method was applied to environmental samples for the determination of analyte ions with satisfactory results (recoveries >95%)

  14. Spectrometric determination of ammonium-nitrogen with quinol in ...

    African Journals Online (AJOL)

    Quinol is proposed as a reagent for the spectrometric determination of ammonium-nitrogen (NH4+-N) in aqueous medium. Quinol forms a pink complex with ammonium salt in aqueous medium. Hydrogen peroxide is needed for colour accentuation. The quinol/ammonium charge transfer complex has absorption maximum ...

  15. Gas chromatography of organic microcontaminants using atomic emission and mass spectrometric detection combined in one instrument (GC-AED/MS)

    NARCIS (Netherlands)

    Mol, H.G.J.; Hankemeier, T.; Brinkman, U.A.T.

    1999-01-01

    This study describes the coupling of an atomic-emission detector and mass-spectrometric detector to a single gas chromatograph. Splitting of the column effluent enables simultaneous detection by atomic-emission detection (AED) and mass spectrometry (MS) and yields a powerful system for the target

  16. Mass Spectrometric C-14 Detection Techniques: Progress Report

    Science.gov (United States)

    Synal, H.

    2013-12-01

    Accelerator Mass Spectrometry (AMS) has been established as the best-suited radiocarbon detection technique. In the past years, significant progress with AMS instrumentation has been made resulting in a boom of new AMS facilities around the World. Today, carbon only AMS systems predominantly utilize 1+ charge state and molecule destruction in multiple ion gas collisions in stripper gas cell. This has made possible a significant simplification of the instruments, a reduction of ion energies and related to this less required space of the installations. However, state-of-the-art AMS instruments have still not reached a development stage where they can be regarded as table-top systems. In this respect, more development is needed to further advance the applicability of radiocarbon not only in the traditional fields of dating but also in biomedical research and new fields in Earth and environmental sciences. In a the proof-of-principle experiment the feasibility of radiocarbon detection over the entire range of dating applications was demonstrated using a pure mass spectrometer and ion energies below 50 keV. Now an experimental platform has been completed to test performance and to explore operation and measurement conditions of pure mass spectrometric radiocarbon detection. This contribution will overview the physical principles, which make this development possible and discuss key parameters of the instrumental design and performance of such an instrument.

  17. Mass spectrometric detection of radiocarbon for dating applications

    Energy Technology Data Exchange (ETDEWEB)

    Synal, H.-A., E-mail: synal@phys.ethz.ch [ETH Zurich, Laboratory of Ion Beam Physics, Building HPK, 8093 Zurich (Switzerland); Schulze-Koenig, T.; Seiler, M.; Suter, M.; Wacker, L. [ETH Zurich, Laboratory of Ion Beam Physics, Building HPK, 8093 Zurich (Switzerland)

    2013-01-15

    Radiocarbon is still the most important nuclide measured by accelerator mass spectrometry (AMS). The related capabilities for dating and tracer studies are eminent not only in archaeology but also drive important applications in the earth and environmental sciences as well as in biomedical research. So far, standard mass spectrometric systems have not been capable of radiocarbon dating because of interfering molecular isobars which, however, can be completely eliminated in charge changing processes at high ion beam energies (MeV) [1,2]. Here, we present a novel type mass spectrometry system for radiocarbon analyses. Radiocarbon dating was performed using 45 keV {sup 14}C ions from the ion source and a molecule dissociation unit kept at ground potential. This proof-of-principle experiment demonstrates for the first time the feasibility of mass spectrometric radiocarbon dating without an accelerator. The results obtained will be the basis of an optimized design for a radiocarbon dating instrument comparable in size, complexity and cost to standard mass spectrometers.

  18. Mass spectrometric detection of radiocarbon for dating applications

    International Nuclear Information System (INIS)

    Synal, H.-A.; Schulze-König, T.; Seiler, M.; Suter, M.; Wacker, L.

    2013-01-01

    Radiocarbon is still the most important nuclide measured by accelerator mass spectrometry (AMS). The related capabilities for dating and tracer studies are eminent not only in archaeology but also drive important applications in the earth and environmental sciences as well as in biomedical research. So far, standard mass spectrometric systems have not been capable of radiocarbon dating because of interfering molecular isobars which, however, can be completely eliminated in charge changing processes at high ion beam energies (MeV) [1,2]. Here, we present a novel type mass spectrometry system for radiocarbon analyses. Radiocarbon dating was performed using 45 keV 14 C ions from the ion source and a molecule dissociation unit kept at ground potential. This proof-of-principle experiment demonstrates for the first time the feasibility of mass spectrometric radiocarbon dating without an accelerator. The results obtained will be the basis of an optimized design for a radiocarbon dating instrument comparable in size, complexity and cost to standard mass spectrometers.

  19. Mass spectrometric detection of radiocarbon for dating applications

    Science.gov (United States)

    Synal, H.-A.; Schulze-König, T.; Seiler, M.; Suter, M.; Wacker, L.

    2013-01-01

    Radiocarbon is still the most important nuclide measured by accelerator mass spectrometry (AMS). The related capabilities for dating and tracer studies are eminent not only in archaeology but also drive important applications in the earth and environmental sciences as well as in biomedical research. So far, standard mass spectrometric systems have not been capable of radiocarbon dating because of interfering molecular isobars which, however, can be completely eliminated in charge changing processes at high ion beam energies (MeV) [1,2]. Here, we present a novel type mass spectrometry system for radiocarbon analyses. Radiocarbon dating was performed using 45 keV 14C ions from the ion source and a molecule dissociation unit kept at ground potential. This proof-of-principle experiment demonstrates for the first time the feasibility of mass spectrometric radiocarbon dating without an accelerator. The results obtained will be the basis of an optimized design for a radiocarbon dating instrument comparable in size, complexity and cost to standard mass spectrometers.

  20. Recent progress in the development of CsI(Tl) crystal-Si-photodiode spectrometric detection assemblies

    International Nuclear Information System (INIS)

    Semynozhenko, V.P.; Grinyov, B.V.; Nekrasov, V.V.; Borodenko, Yu.A.

    2005-01-01

    Highly sensitive spectrometric γ-detection assemblies are developed using a comprehensive approach (optimization of crystal growth conditions as well as of treatment and packing of scintillators, creation of low-noise charge-sensitive preamplifiers and shapers). The detection assemblies with CsI(Tl)≤100 cm 3 have a sensitivity of about 20 pulse/s(mcR/h), their energy resolution with respect to 137 Cs γ-line being ≤8.5%. The assemblies with lesser scintillator volumes (1-5 cm 3 ) provide a resolution lower than 6% with respect to 137 Cs and ≤40% with respect to 241 Am

  1. NZG 201 portable spectrometric unit

    International Nuclear Information System (INIS)

    Jursa, P.; Novakova, O.; Slezak, V.

    The NZG 201 spectrometric unit is a portable single-channel processing unit supplied from the mains or a battery which allows the qualitative and quantitative measurement of different types of ionizing radiation when connected to a suitable detection unit. The circuit layout and the choice of control elements makes the spectrometric unit suitable for use with scintillation detector units. The spectrometric unit consists of a pulse amplifier, an amplitude pulse analyzer, a pulse counter, a pulse rate counter with an output for a recorder, a high voltage source and a low voltage source. The block diagram is given. All circuits are modular and are mounted on PCB's. The apparatus is built in a steel cabinet with a raised edge which protects the control elements. The linear pulse amplifier has a maximum gain of 1024, the pulse counter has a maximum capacity of 10 6 -1 imp and time resolution better than 0.5 μs. The temperature interval at which the apparatus is operational is 0 to 45 degC, its weight is 12.5 kg and dimensions 36x280x310 mm, energy range O.025 to 2.5 MeV, for 137 Cs the energy resolution is 8 to 10%. The spectrometric unit NZG 2O1 may, with regard to its parameters, number and range of control elements, be used as a universal measuring unit. (J.P.)

  2. Spectrometric assembly for portable installations

    International Nuclear Information System (INIS)

    Kluger, A.; Popescu, C.

    1997-01-01

    The components of the portable spectrometric assembly are: - the detecting probe with Na I(Tl) crystal and air-tight case of industrial type; - a microcomputer; - a unit of analogical processing of the signal from the detecting probe; - a single-channel analyzer with adjustable threshold; - commands and display module; - a source of high voltage; - an electrical supply battery. The device uses the method of gamma photons detection in energetic windows. Through theoretical and experimental studies carried out during the prototype development phase, the superiority of this method has been proved as compared with the installations which make use of the classical principle of photon integral detection. The achieved prototype has a basic program enabling the setting of all working parameters (measuring time, discriminating thresholds, discriminators operating conditions, etc.). Through the included interface RS232 it is possible to transmit the data to a more powerful computer in order to continually process the results. The spectrometric assembly, realized on the basis of micro-computers, can be used in a wide range of applications: measurement of thickness and erosion of walls and tubes, measurement of level in closed containers, of soil density, etc. The adjustment for specific application is performed only through a program modification. (authors)

  3. Analysis of Endocrine Disrupting Pesticides by Capillary GC with Mass Spectrometric Detection

    Directory of Open Access Journals (Sweden)

    Svetlana Hrouzková

    2012-09-01

    Full Text Available Endocrine disrupting chemicals, among them many pesticides, alter the normal functioning of the endocrine system of both wildlife and humans at very low concentration levels. Therefore, the importance of method development for their analysis in food and the environment is increasing. This also covers contributions in the field of ultra-trace analysis of multicomponent mixtures of organic pollutants in complex matrices. With this fact conventional capillary gas chromatography (CGC and fast CGC with mass spectrometric detection (MS has acquired a real importance in the analysis of endocrine disrupting pesticide (EDP residues. This paper provides an overview of GC methods, including sample preparation steps, for analysis of EDPs in a variety of matrices at ultra-trace concentration levels. Emphasis is put on separation method, mode of MS detection and ionization and obtained limits of detection and quantification. Analysis time is one of the most important aspects that should be considered in the choice of analytical methods for routine analysis. Therefore, the benefits of developed fast GC methods are important.

  4. Calibration of a leak detection spectrometer; Calibration d'un spectrometre detecteur de fuites

    Energy Technology Data Exchange (ETDEWEB)

    Geller, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    This paper describes a study of the possible methods for calibrating a leak detection spectrometer, and the estimation of outputs from the leaks is considered. With this in mind the question of sensitivity of leak detection is tackled on a very general level; first the sensitivity of the isolated instrument is determined, and then the sensitivity of an instrument connected to an installation where leaks may be suspected. Finally, practical solutions are proposed. (author) [French] Dans cet article, nous etudions les methodes possibles de calibration d'un spectrometre detecteur de fuites et nous envisageons l'evaluation des debits de fuites trouves. Pour cela, nous abordons la notion de sensibilite de la detection de fuite sur un plan tres general; d'abord nous determinons la sensibilite de l'appareil isole, ensuite la sensibilite d'un appareil connecte sur une installation ou l'on cherche les fuites. Enfin, nous preconisons des solutions pratiques. (auteur)

  5. Atomic-absorption spectrometric determination of cobalt, nickel, and copper in geological materials with matrix masking and chelation-extraction

    Science.gov (United States)

    Sanzolone, R.F.; Chao, T.T.; Crenshaw, G.L.

    1979-01-01

    An atomic-absorption spectrometric method is reported for the determination of cobalt, nickel, and copper in a variety of geological materials including iron- and manganese-rich, and calcareous samples. The sample is decomposed with HP-HNO3 and the residue is dissolved in hydrochloric acid. Ammonium fluoride is added to mask iron and 'aluminum. After adjustment to pH 6, cobalt, nickel, and copper are chelated with sodium diethyl-dithiocarbamate and extracted into methyl isobutyl ketone. The sample is set aside for 24 h before analysis to remove interferences from manganese. For a 0.200-g sample, the limits of determination are 5-1000 ppm for Co, Ni, and Cu. As much as 50% Fe, 25% Mn or Ca, 20% Al and 10% Na, K, or Mg in the sample either individually or in various combinations do not interfere. Results obtained on five U.S. Geological Survey rock standards are in general agreement with values reported in the literature. ?? 1979.

  6. Mass spectrometric detection of radiocarbon for dating applications

    OpenAIRE

    Synal Hans-Arno

    2013-01-01

    Radiocarbon is still the most important nuclide measured by accelerator mass spectrometry (AMS). The related capabilities for dating and tracer studies are eminent not only in archaeology but also drive important applications in the earth and environmental sciences as well as in biomedical research. So far standard mass spectrometric systems have not been capable of radiocarbon dating because of interfering molecular isobars which however can be completely eliminated in charge changing proces...

  7. Spectrometric techniques 4

    CERN Document Server

    Vanasse, George A

    2013-01-01

    Spectrometric Techniques, Volume IV discusses three widely diversified areas of spectrometric techniques. The book focuses on three spectrometric methods. Chapter 1 discusses the phenomenology and applications of Coherent Anti-Stokes Raman Spectroscopy (CARS), the most commonly used optical technique that exploit the Raman effect. The second chapter is concerned with diffraction gratings and mountings for the Vacuum Ultraviolet Spectral Region. Chapter 3 accounts the uses of mass spectrometry, detectors, types of spectrometers, and ion sources. Physicists and chemists will find the book a go

  8. Spectrometric properties and radiation damage of BGO crystals

    Science.gov (United States)

    Kim, Gen C.; Gasanov, Eldar M.

    1997-07-01

    Spectrometric properties, such as light output, energy resolution BGO crystals before and after (superscript 60)Co gamma-ray (dose 10(superscript 4) - 10(superscript 6) R) and neutron irradiation (fluence 10(superscript 14) cm(superscript -2)) are investigated. Condition for degradation of spectrometric properties and their recovering after irradiation are studied. The energy spectrum of the photons emitted from BGO crystals irradiated with neutron fluence contains the long living background peak which is caused by self-irradiation with radioactive isotopes produced in the crystals. The defect production was studied in crystals under the high dose gamma-irradiation with (superscript 60)Co isotope. It was found that after doses above 10(superscript 8) R the color center at 365 nm and doses higher than 10(superscript 9) R a wide absorption band in the region of 300 - 350 nm occur. Comparison of these results with those of reactor irradiation has shown that under the high dose gamma-irradiation the structure defect production takes place.

  9. Determination of trace elements in Egyptian cane sugar (Deshna Factories) by neutron activation, atomic absorption spectrophotometric and inductively coupled plasma-atomic emission spectrometric analysis

    International Nuclear Information System (INIS)

    Awadallah, R.M.; Sherif, M.K.; Mohamed, A.E.; Grass, F.

    1986-01-01

    Multielement instrumental neutron activation (INAA), inductively coupled plasma-atomic emission spectrometric (ICP-AES) and atomic absorption spectrophotometric (AAS) analyses were utilized for the determination of Ag, Al, As, Au, Ba, Be, Br, Ca, Cd, Ce, Cl, Co, Cr, Cu, Eu, Fe, Ga, Hf, K, La, Li, Lu, Mg, Mn, Na, Nb, Ni, P, Pb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Th, Ti, U, V, W and Zn in sugar cane plant, raw juice, juice in different stages, syrup, deposits, molasses, A, B and C sugar, refinery 1 and 2 sugar, and in soil samples picked up from the immediate vicinity of the cane plant roots at surface, 30 and 60 cm depth, respectively. (author)

  10. Mass spectrometric detection of proteins in non-aqueous media : the case of prion proteins in biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Douma, M.D.; Kerr, G.M.; Brown, R.S.; Keller, B.O.; Oleschuk, R.D. [Queen' s Univ., Kingston, ON (Canada). Dept. of Chemistry

    2008-08-15

    This paper presented a filtration method for detecting protein traces in non-aqueous media. The extraction technique used a mixture of acetonitrile, non-ionic detergent and water along with filter disks with embedded C{sub 8}-modified silica particles to capture the proteins from non-aqueous samples. The extraction process was then followed by an elution of the protein from the filter disk and direct mass spectrometric detection and tryptic digestion with peptide mapping and MS/MS fragmentation of protein-specific peptides. The method was used to detect prion proteins in spiked biodiesel samples. A tryptic peptide with the sequence YGQGSPGGNR was used for unambiguous identification. Results of the study showed that the method is suitable for the large-scale testing of protein impurities in tallow-based biodiesel production processes. 33 refs., 6 figs.

  11. APPLICATION OF THE SPECTROMETRIC METHOD FOR CALCULATING THE DOSE RATE FOR CREATING CALIBRATION HIGHLY SENSITIVE INSTRUMENTS BASED ON SCINTILLATION DETECTION UNITS

    Directory of Open Access Journals (Sweden)

    R. V. Lukashevich

    2017-01-01

    Full Text Available Devices based on scintillation detector are highly sensitive to photon radiation and are widely used to measure the environment dose rate. Modernization of the measuring path to minimize the error in measuring the response of the detector to gamma radiation has already reached its technological ceiling and does not give the proper effect. More promising for this purpose are new methods of processing the obtained spectrometric information. The purpose of this work is the development of highly sensitive instruments based on scintillation detection units using a spectrometric method for calculating dose rate.In this paper we consider the spectrometric method of dosimetry of gamma radiation based on the transformation of the measured instrumental spectrum. Using predetermined or measured functions of the detector response to the action of gamma radiation of a given energy and flux density, a certain function of the energy G(E is determined. Using this function as the core of the integral transformation from the field to dose characteristic, it is possible to obtain the dose value directly from the current instrumentation spectrum. Applying the function G(E to the energy distribution of the fluence of photon radiation in the environment, the total dose rate can be determined without information on the distribution of radioisotopes in the environment.To determine G(E by Monte-Carlo method instrumental response function of the scintillator detector to monoenergetic photon radiation sources as well as other characteristics are calculated. Then the whole full-scale energy range is divided into energy ranges for which the function G(E is calculated using a linear interpolation.Spectrometric method for dose calculation using the function G(E, which allows the use of scintillation detection units for a wide range of dosimetry applications is considered in the article. As well as describes the method of calculating this function by using Monte-Carlo methods

  12. Inductively coupled plasma emission spectrometric detection of simulated high performance liquid chromatographic peaks

    International Nuclear Information System (INIS)

    Fraley, D.M.; Yates, D.; Manahan, S.E.

    1979-01-01

    Because of its multielement capability, element-specificity, and low detection limits, inductively coupled plasma optical emission spectrometry (ICP) is a very promising technique for the detection of specific elemental species separated by high performance liquid chromatography (HPLC). This paper evaluated ICP as a detector for HPLC peaks containing specific elements. Detection limits for a number of elements have been evaluated in terms of the minimum detectable concentration of the element at the chromatographic peak maximum. The elements studies were Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Sr, Ti, V, and Zn. In addition, ICP was compared with atomic absorption spectrometry for the detection of HPLC peaks composed of EDTA and NTA chelates of copper. Furthermore, ICP was compared to uv solution absorption for the detection of copper chelates. 6 figures, 4 tables

  13. Extraction and preconcentration of trace Al and Cr from vegetable samples by vortex-assisted ionic liquid-based dispersive liquid-liquid microextraction prior to atomic absorption spectrometric determination.

    Science.gov (United States)

    Altunay, Nail; Yıldırım, Emre; Gürkan, Ramazan

    2018-04-15

    In the study, a simple, and efficient microextraction approach, which is termed as vortex-assisted ionic liquid-based dispersive liquid-liquid microextraction (VA-IL-DLLME), was developed for flame atomic absorption spectrometric analysis of aluminum (Al) and chromium (Cr) in vegetables. The method is based on the formation of anionic chelate complexes of Al(III) and Cr(VI) with o-hydroxy azo dye, at pH 6.5, and then extraction of the hydrophobic ternary complexes formed in presence of cetyltrimethylammonium bromide (CTAB) into a 125 μL volume of 1-butyl-3-methylimidazolium bis(trifluorosulfonyl)imide [C 4 mim][Tf 2 N]) as extraction solvent. Under optimum conditions, the detection limits were 0.02 µg L -1 in linear working range of 0.07-100 µg L -1 for Al(III), and 0.05 µg L -1 in linear working range of 0.2-80 µg L -1 for Cr(VI). After the validation by analysis of a certified reference material (CRM), the method was successfully applied to the determination of Al and Cr in vegetables using standard addition method. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Detection, characterization and quantification of salicylic acid conjugates in plant extracts by ESI tandem mass spectrometric techniques.

    Science.gov (United States)

    Pastor, Victoria; Vicent, Cristian; Cerezo, Miguel; Mauch-Mani, Brigitte; Dean, John; Flors, Victor

    2012-04-01

    An approach for the detection and characterization of SA derivatives in plant samples is presented based on liquid chromatography coupled to electrospray ionization (ESI) tandem mass spectrometric techniques. Precursor ion scan methods using an ESI triple quadrupole spectrometer for samples from plants challenged with the virulent Pseudomonas syringae pv tomato DC3000 allowed us to detect two potential SA derivatives. The criterion used to consider a potential SA derivative is based on the detection of analytes in the precursor ion scan chromatogram upon selecting m/z 137 and m/z 93 that correspond to the salicylate and its main product ion, respectively. Product ion spectra of the newly-detected analytes as well as accurate m/z determinations using an ESI Q-time-of-flight instrument were registered as means of characterization and strongly suggest that glucosylated forms of SA at the carboxylic and at the phenol functional groups are present in plant samples. The specific synthesis and subsequent chromatography of salicylic glucosyl ester (SGE) and glucosyl salicylate (SAG) standards confirmed the chemical identity of both peaks that were obtained applying different tandem mass spectrometric techniques and accurate m/z determinations. A multiple reaction monitoring method has been developed and applied to plant samples. The advantages of this LC-ESI-MS/MS methods with respect to the traditional analysis of glucosyl conjugates are also discussed. Preliminary results revealed that SA and the glucosyl conjugates are accumulated in Arabidopsis thaliana in a time dependent manner, accordingly to the up-regulation of SA-dependent defenses following P. syringae infection. This technique applied to plant hormones or fragment ions may be useful to obtain chemical family members of plant metabolites and help identify their contribution in the signaling of plant defenses. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  15. Coupling continuous ultrasound-assisted extraction, preconcentration and flame atomic absorption spectrometric detection for the determination of cadmium and lead in mussel samples

    International Nuclear Information System (INIS)

    Yebra-Biurrun, M.C.; Cancela-Perez, S.; Moreno-Cid-Barinaga, A.

    2005-01-01

    Continuous ultrasound-assisted extraction has been coupled with preconcentration and flame atomic absorption spectrometry for the determination of cadmium and lead in mussel samples. Experimental designs were used for the optimisation of the leaching and preconcentration steps. The use of diluted nitric acid as extractant in the continuous mode at a flow rate of 3.5 ml min -1 and room temperature was sufficient for quantitative extraction of these trace metals. A minicolumn containing a chelating resin (Chelite P, with aminomethylphosphoric acid groups) was proved as an excellent material for the quantitative preconcentration of cadmium and lead prior to their flame atomic absorption detection. A flow injection manifold was used as interface for coupling the three analytical steps, which allowed the automation of the whole analytical process. A good precision of the whole procedure (2.0 and 2.3%), high enrichment factors (20.5 and 11.8) and a detection limit of 0.011 and 0.25 μg g -1 for cadmium and lead, respectively, were obtained for 80 mg of sample. The sample throughputs were ca. 16 and 14 samples h -1 for cadmium and lead, respectively. The accuracy of the analytical procedures was verified by using a standard reference material (BCR 278-R, mussel tissue) and the results were in good agreement with the certified values. The method was successfully applied to the determination of trace amounts of cadmium and lead in mussel samples from the coast of Galicia (NW, Spain)

  16. Ultraviolet absorption detection of DNA in gels

    International Nuclear Information System (INIS)

    Mahon, A.R.

    1998-01-01

    A method and apparatus for the detection and quantification of large fragments of unlabelled deoxyribonucleic acid (DNA) in agarose gels is presented. The technique is based on ultra-violet (UV) absorption by nucleotides. A deuterium lamp was used to illuminate regions of an electrophoresis gel. As DNA bands passed through the illuminated region of the gel the amount of UV light transmitted was reduced due to DNA absorption. Two detection systems were investigated. In the first system, synthetic chemical vapour deposition (CVD) diamond strip detectors were used to locate regions of DNA in the gels by detecting the transmitted light. CVD diamond has a high indirect band gap of 5.45 eV and is therefore sensitive to UV photons of wavelengths < 224 nm. A number of CVD diamond samples were characterised to investigate their suitability as detectors for this application. The detectors' quantum efficiency, UV response and time response were measured. DNA bands containing as little as 20 ng were detected by the diamond. In a second system, a deuterium lamp was used to illuminate individual sample lanes of an electrophoresis gel via an array of optical fibres. During electrophoresis the regions of DNA were detected with illumination at 260 nm, using a UV-sensitive charge coupled device (CCD). As the absorption coefficient of a DNA sample is approximately proportional to its mass, the technique is inherently quantitative. This system had a detection limit of 0.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. Using this detection technique, the DNA sample remains in its native state. The removal of carcinogenic dyes from the detection procedure greatly reduces associated biological hazards. (author)

  17. Identification of volatiles by headspace gas chromatography with simultaneous flame ionization and mass spectrometric detection.

    Science.gov (United States)

    Tiscione, Nicholas B; Yeatman, Dustin Tate; Shan, Xiaoqin; Kahl, Joseph H

    2013-10-01

    Volatiles are frequently abused as inhalants. The methods used for identification are generally nonspecific if analyzed concurrently with ethanol or require an additional analytical procedure that employs mass spectrometry. A previously published technique utilizing a capillary flow technology splitter to simultaneously quantitate and confirm ethyl alcohol by flame ionization and mass spectrometric detection after headspace sampling and gas chromatographic separation was evaluated for the detection of inhalants. Methanol, isopropanol, acetone, acetaldehyde, toluene, methyl ethyl ketone, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, 1,1-difluoroethane, 1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane (Norflurane, HFC-134a), chloroethane, trichlorofluoromethane (Freon®-11), dichlorodifluoromethane (Freon®-12), dichlorofluoromethane (Freon®-21), chlorodifluoromethane (Freon®-22) and 1,2-dichlorotetrafluoroethane (Freon®-114) were validated for qualitative identification by this method. The validation for qualitative identification included evaluation of matrix effects, sensitivity, carryover, specificity, repeatability and ruggedness/robustness.

  18. Graphite furnace atomic absorption spectrometric determination of Ni and Pb in diesel and gasoline samples stabilized as microemulsion using conventional and permanent modifiers

    International Nuclear Information System (INIS)

    Matos Reyes, Mariela N.; Campos, Reinaldo C.

    2005-01-01

    A procedure for the graphite furnace atomic absorption spectrometric determination of Ni and Pb in diesel and gasoline samples was developed. Sample stabilization was necessary because of evident analyte losses that occurred immediately after sampling. Excellent long-term sample stabilization was observed by mixing different organic solvents with propan-1-ol and 50% vol/vol HNO 3 at a 3.3:6.5:1 volume ratio. For Pb, efficient thermal stabilization was obtained using aqueous Pd-Mg modifier as well as for Ir as permanent modifier. The drying temperature and ramp rate influenced the sensitivity obtained for Ni, and had to be carefully optimized. Taking this into account, the same sensitivity was attained in all investigated organic media stabilized as microemulsion. Thus, calibration with microemulsions prepared with a single organic solvent was possible, using aqueous or organic stock solutions. Commercial gasoline and diesel samples were directly analyzed after stabilization as microemulsion and by comparative UOP procedures. n-Hexane microemulsions were used for calibration, and good agreement was obtained between the results using the proposed and comparative procedures. Typical coefficients of variation (n = 6) ranged from 1% to 4%, and from 1% to 3% for Ni and Pb, respectively. Detection limits (k = 3) in the original gasoline or diesel samples, derived from 10 blank measurements, were 4.5 and 3.6 μg l -1 for Ni and Pb, respectively, comfortably below the values found in the analyzed samples

  19. Aspects of optical fibers and spectrometric sensors in chemical process and industrial environments

    International Nuclear Information System (INIS)

    Boisde, G.; Perez, J.J.

    1988-01-01

    For on-line control, the two alternatives of automatic sample transfer and in situ remote analysis are discussed. New concepts are emerging from the possibilities offered by optical fibers. Absorption in the visible, UV and IR, fluorescence and Raman spectrometric techniques are examined. The state of the art of optodes and devices in chemical process control are given, with some examples of applications in nuclear plants

  20. Direct determination of beryllium, cadmium, lithium, lead and silver in thorium nitrate solution by electrothermal atomization atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Thulasidas, S.K.; Kulkarni, M.J.; Porwal, N.K.; Page, A.G.; Sastry, M.D.

    1988-01-01

    An electrothermal atomization atomic absorption spectrometric (ET-AAS) method is developed for the direct determination of Ag, Be, Cd, Li and Pb in thorium nitrate solution. The method offers detection of sub-nanogram amounts of these analytes in 100-microgram thorium samples with a precision of around 10%. A number of spiked samples and pre-analyzed ThO 2 samples have been analyzed to evaluate the performance of the analytical methods developed here

  1. Identification of organic sulfur compounds in coal bitumen obtained by different extraction techniques using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Maria Elisabete; Cappelli Fontanive, Fernando; Bastos Caramao, Elina; Alcaraz Zini, Claudia [Universidade Federal do Rio Grande do Sul, Instituto de Quimica, Porto Alegre, RS (Brazil); Oliveira, Jose Vladimir de [URI, Universidade Regional Integrada do Alto Uruguai e das Missoes, Erechim, RS (Brazil)

    2011-11-15

    The determination of organic sulfur compounds (OSC) in coal is of great interest. Technically and operationally these compounds are not easily removed and promote corrosion of equipment. Environmentally, the burning of sulfur compounds leads to the emission of SO{sub x} gases, which are major contributors to acid rain. Health-wise, it is well known that these compounds have mutagenic and carcinogenic properties. Bitumen can be extracted from coal by different techniques, and use of gas chromatography coupled to mass spectrometric detection enables identification of compounds present in coal extracts. The OSC from three different bitumens were tentatively identified by use of three different extraction techniques: accelerated solvent extraction (ASE), ultrasonic extraction (UE), and supercritical-fluid extraction (SFE). Results obtained from one-dimensional gas chromatography (1D GC) coupled to quadrupole mass spectrometric detection (GC-qMS) and from two-dimensional gas chromatography with time-of-flight mass spectrometric detection (GC x GC-TOFMS) were compared. By use of 2D GC, a greater number of OSC were found in ASE bitumen than in SFE and UE bitumens. No OSC were identified with 1D GC-qMS, although some benzothiophenes and dibenzothiophenes were detected by use of EIM and SIM modes. GC x GC-TOFMS applied to investigation of OSC in bitumens resulted in analytical improvement, as more OSC classes and compounds were identified (thiols, sulfides, thiophenes, naphthothiophenes, benzothiophenes, and benzonaphthothiophenes). The roof-tile effect was observed for OSC and PAH in all bitumens. Several co-elutions among analytes and with matrix interferents were solved by use of GC x GC. (orig.)

  2. The leakage problem in vacuum system. Realization of a mass spectrometer detecting leaks; Le probleme des fuites en technique du vide. Realisation d'un spectrometre de masse detecteur de fuite

    Energy Technology Data Exchange (ETDEWEB)

    Geller, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1954-11-15

    In the first part of this paper we consider the problem of leaks in vacuum systems, and their detection. We consider in particular the method of detection by means of a helium spectrometer. The second part deals with the experimental set p. The analyser and the ion source have been studied in great detail, and we have also discussed the technological and mechanical aspects of the apparatus and its performances. (author) [French] Dans la premiere partie de ce travail, nous traitons le probleme des fuites en technique du vide et leur detection en general. La methode de detection par spectrometre a helium y est envisagee plus particulierement. La deuxieme partie de l'article est consacree a la realisation du spectrometre. Le tube analyseur et la source d'ions y sont etudies en detail. Nous exposons de meme les conceptions technologiques et mecaniques de l'appareil ainsi que ses performances. (auteur)

  3. Spectrometric techniques 3

    CERN Document Server

    Vanasse, George A

    2013-01-01

    Spectrometric Techniques, Volume III presents the applications of spectrometric techniques to atmospheric and space studies. This book reviews the spectral data processing and analysis techniques that are of broad applicability.Organized into five chapters, this volume begins with an overview of the instrumentation used for obtaining field data. This text then reviews the contribution that space-borne spectroscopy in the thermal IR has made to the understanding of the planets. Other chapters consider the instruments that have recorded the planetary emission spectra. This book discusses as well

  4. Mass Spectrometric Characteristics of Prenylated Indole Derivatives from Marine-Derived Penicillium sp. NH-SL.

    Science.gov (United States)

    Ding, Hui; Ding, Wanjing; Ma, Zhongjun

    2017-03-22

    Two prenylated indole alkaloids were isolated from the ethyl acetate extracts of a marine-derived fungus Penicillium sp. NH-SL and one of them exhibited potent cytotoxic activity against mouse hepa 1c1c7 cells. In order to detect other bioactive analogs, we used liquid chromatogram tandem mass spectrometry (LC-MS/MS) to analyze the mass spectrometric characteristics of the isolated compounds as well as the crude extracts. As a result, three other analogs were detected, and their structures were deduced according to the similar fragmentation patterns. This is the first systematic report on the mass spectrometric characteristics of prenylated indole derivatives.

  5. Changing of Bacteria Catalase Activity Under the Influence of Electro-Magnetic Radiation on a Frequency of Nitric Oxide Absorption and Radiation Molecular Spectrum

    Directory of Open Access Journals (Sweden)

    G.M. Shub

    2009-09-01

    Full Text Available The dynamics of catalase activity degree changing in Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa is described under the influence of electro-magnetic radiation on a frequency of nitric oxide absorption and radiation molecular spectrum. The panoramic spectrometric measuring complex, developed in Central Scientific Research Institute of measuring equipment Public corporation, Saratov, was used while carrying out the research. Electromagnetic vibrations of extremely high frequencies were stimulated in this complex imitating the structure of nitric oxide absorption and radiation molecular spectrum. The growth of activity of the mentioned enzyme of the strains under research was detected. The most significant changes were observed under 60-minutes exposure.

  6. Mass spectrometric confirmation criterion for product-ion spectra generated in flow-injection analysis. Environmental application

    NARCIS (Netherlands)

    Geerdink, R.B.; Niessen, W.M.A.; Brinkman, U.A.T.

    2001-01-01

    The suitability of a confirmation criterion recently recommended in the Netherlands for gas chromatography with mass spectrometric detection (GC-MS), was evaluated for flow-injection analysis (FIA) with atmospheric pressure chemical ionisation MS-MS detection. The main feature of the criterion is

  7. Quantitative analysis of sodium di-uranate for Al, Ca, Fe, Mg, Mn, Na by flame-atomic absorption spectrometric method

    International Nuclear Information System (INIS)

    Jat, J.R.; Balaji Rao, Y.; Subba Rao, Y.

    2015-01-01

    Nuclear Fuel Complex (NFC) receives Sodium Di-Uranate (SDU) from Uranium Corporation of India Limited (UCIL) for producing sinterable UO 2 pellets for manufacturing fuel sub assemblies. Several impurities present in ore find their way into SDU during its conversion. Stringent specification have been laid down by the reactor designs for achieving the optimum performance of the fuel and several impurity element like Al, Ca, Fe, Mg, Mn, Na among others affects severely performance of UO 2 fuel. Most of the impurity including the above mentioned elements are generally analysed by ICP-OES method. However, determination of Al, Ca, Fe, Mg, Mn and Na by ICP-OES requires lot of dilution as they are present at high levels in SDU. Apart from introducing dilution error, dilution process is very tedious and time consuming work and not a preferred choice in an industrial lab like control lab where large analytical load exists and time bound analysis is a requirement. To avoid these difficulties a simple and reliable Flame Atomic absorption spectrometric technique has been developed for regular analysis. Present method involves dissolution of SDU sample in Conc. HNO 3 and after the complete dissolution the sample solution has been evaporated to near dryness on a hot plate. Subsequently sample solution has been brought into 4N HNO 3 medium

  8. 5th colloquium on atomic spectrometric trace analysis

    International Nuclear Information System (INIS)

    Welz, B.

    1989-01-01

    This book deals with apparatus, use-oriented and theoretical aspects of trace analysis and spectroscopy. General articles are concerned with the analysis of environmentally relevant samples; a comparison of modern spectroscopic techniques, the coupling of hydride production, chromatography and spectrometry; chemical modifiers for graphite tube furnace atomic absorption spectroscopy (AAS), and possible applications of flow injection to atomic spectrometric trace analysis - one of the outstanding subjects of the colloquium. About one quarter of the 85 contributions deals with new techniques including flow injection. Other priority subjects are the theory and application of graphite tube furnace AAS, and a comparison between different dissolution methods and direct solid analysis. Medicine and toxicology, analysis of biological materials and environmentally relevant samples are in the foreground of use-oriented papers. (orig./BBR) [de

  9. Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review

    International Nuclear Information System (INIS)

    Herrero Latorre, C.; Álvarez Méndez, J.; Barciela García, J.; García Martín, S.; Peña Crecente, R.M.

    2012-01-01

    Highlights: ► The use of CNTs as sorbent for metal species in solid phase extraction has been described. ► Physical and chemical strategies for functionalization of carbon nanotubes have been discussed. ► Published analytical methods concerning solid phase extraction and atomic spectrometric determination have been reviewed. - Abstract: New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes – due to their high adsorption and desorption capacities – have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.

  10. Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review

    Energy Technology Data Exchange (ETDEWEB)

    Herrero Latorre, C., E-mail: carlos.herrero@usc.es [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain); Alvarez Mendez, J.; Barciela Garcia, J.; Garcia Martin, S.; Pena Crecente, R.M. [Universidad de Santiago de Compostela, Dpto. Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Alfonso X el Sabio s/n, 27002 Lugo (Spain)

    2012-10-24

    Highlights: Black-Right-Pointing-Pointer The use of CNTs as sorbent for metal species in solid phase extraction has been described. Black-Right-Pointing-Pointer Physical and chemical strategies for functionalization of carbon nanotubes have been discussed. Black-Right-Pointing-Pointer Published analytical methods concerning solid phase extraction and atomic spectrometric determination have been reviewed. - Abstract: New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes - due to their high adsorption and desorption capacities - have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.

  11. A sensitive mass spectrometric method for hypothesis-driven detection of peptide post-translational modifications: multiple reaction monitoring-initiated detection and sequencing (MIDAS).

    Science.gov (United States)

    Unwin, Richard D; Griffiths, John R; Whetton, Anthony D

    2009-01-01

    The application of a targeted mass spectrometric workflow to the sensitive identification of post-translational modifications is described. This protocol employs multiple reaction monitoring (MRM) to search for all putative peptides specifically modified in a target protein. Positive MRMs trigger an MS/MS experiment to confirm the nature and site of the modification. This approach, termed MIDAS (MRM-initiated detection and sequencing), is more sensitive than approaches using neutral loss scanning or precursor ion scanning methodologies, due to a more efficient use of duty cycle along with a decreased background signal associated with MRM. We describe the use of MIDAS for the identification of phosphorylation, with a typical experiment taking just a couple of hours from obtaining a peptide sample. With minor modifications, the MIDAS method can be applied to other protein modifications or unmodified peptides can be used as a MIDAS target.

  12. Quantum dots assisted laser desorption/ionization mass spectrometric detection of carbohydrates: qualitative and quantitative analysis.

    Science.gov (United States)

    Bibi, Aisha; Ju, Huangxian

    2016-04-01

    A quantum dots (QDs) assisted laser desorption/ionization mass spectrometric (QDA-LDI-MS) strategy was proposed for qualitative and quantitative analysis of a series of carbohydrates. The adsorption of carbohydrates on the modified surface of different QDs as the matrices depended mainly on the formation of hydrogen bonding, which led to higher MS intensity than those with conventional organic matrix. The effects of QDs concentration and sample preparation method were explored for improving the selective ionization process and the detection sensitivity. The proposed approach offered a new dimension to the application of QDs as matrices for MALDI-MS research of carbohydrates. It could be used for quantitative measurement of glucose concentration in human serum with good performance. The QDs served as a matrix showed the advantages of low background, higher sensitivity, convenient sample preparation and excellent stability under vacuum. The QDs assisted LDI-MS approach has promising application to the analysis of carbohydrates in complex biological samples. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Significance of Airborne Gamma-ray spectrometric data of Umm bisilla Area, central Eastern Desert, Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Rabie, S I [Nuclear materials authority, Maadi, Cairo, (Egypt)

    1995-10-01

    Umm bisilla area, located in the Central Eastern Desert of Egypt, consists mainly of basement rocks. The present investigation of the airborne spectrometric data is to define the meaningful anomalies from the raw data by applying the significance factor techniques, by calculating the significant radioactive provinces. Determination of the gross structural pattern and broad variations in composition of the crystalline basement, to define the relationships between the tectonic features of the area as interpreted from aeromagnetic data, with the significant anomalies revealed from spectrometric data was carried out through the application of different magnetic techniques. Five significant uraniferous zones were detected associated with Umm Bisilla granite, amphibolite, and grey granite. The intersection of the structural lineaments interpreted from aeromagnetic data illustrated good correlation with the significant uranium anomalous zones interpreted from spectrometric data, and indicated that the concentration is structurally. 15 figs.

  14. Thermionic detection of the ionic fragments of continiuum-state pair absorption systems

    International Nuclear Information System (INIS)

    Hotop, R.; Niemax, K.; Richter, J.; Weber, K.H.

    1981-01-01

    Using a thermionic diode we have detected the ionic fragments formed by associative ionization and dissociation after continuum-state pair absorption processes in Cs-Cs and Cs-K systems. Assuming an ionization probability of unity of the excited species and calibrating the pair absorption bands by taking into account the known photoionization cross section of the atoms we found excellent agreement with data from classical absorption measurements. (orig.)

  15. Spectrometric methods for the determination of chlorine in crude oil and petroleum derivatives — A review

    International Nuclear Information System (INIS)

    Doyle, Adriana; Saavedra, Alvaro; Tristão, Maria Luiza B.; Mendes, Luiz A.N.; Aucélio, Ricardo Q.

    2013-01-01

    Chlorine determination in crude oil is made in order to guarantee that the oil does not contain levels of this element that might cause damages in the oil processing equipment. In petroleum products, the determination of chlorine is made, for instance, to evaluate if there are proper concentrations of organochloride compounds, which are used as additives. Such determinations are currently performed following official guidelines from the ASTM International and from the United States Environmental Protection Agency as well as protocols indicated by the Universal Oil Products. X-ray fluorescence spectroscopy plays an important role in many of these official methods. In contrast, other spectrometric methods based on optical and mass detection are plagued by limitations related to both the fundamental characteristics of non-metals and to the complex sample matrices, which reflects in the small number of articles devoted to these applications. In this review, the current status of the spectrometric methods, especially the role played by X-ray fluorescence spectrometry, is evaluated in terms of the determination of chlorine in crude oil and petroleum derivatives. Comparison of the performance of the methods, limitations and potential new approaches to ensure proper spectrometric determinations of chlorine is indicated. - Highlights: • Critical evaluation of spectrometric methods for chlorine in petroleum products. • Reviews on element determination in petroleum have not address the case of chlorine. • Peculiarities of the spectrometric determination of Cl in petroleum are discussed. • The spectrometric approaches are detailed and compared to the official methods. • New trends in chlorine determination in petroleum products are indicated

  16. Mobile spectrometric laboratory

    International Nuclear Information System (INIS)

    Isajenko, K.A.; Lipinski, P.

    2002-01-01

    The article presents the Mobile Spectrometric Laboratory used by Central Laboratory for Radiological Protection since year 2000. The equipment installed in the Mobile Laboratory and its uses is described. The results of international exercises and intercalibrations, in which the Laboratory participated are presented. (author)

  17. Visual and light scattering spectrometric method for the detection of melamine using uracil 5‧-triphosphate sodium modified gold nanoparticles

    Science.gov (United States)

    Liang, Lijiao; Zhen, Shujun; Huang, Chengzhi

    2017-02-01

    A highly selective method was presented for colorimetric determination of melamine using uracil 5‧-triphosphate sodium modified gold nanoparticles (UTP-Au NPs) in this paper. Specific hydrogen-bonding interaction between uracil base (U) and melamine resulted in the aggregation of AuNPs, displaying variations of localized surface plasmon resonance (LSPR) features such as color change from red to blue and enhanced localized surface plasmon resonance light scattering (LSPR-LS) signals. Accordingly, the concentration of melamine could be quantified based on naked eye or a spectrometric method. This method was simple, inexpensive, environmental friendly and highly selective, which has been successfully used for the detection of melamine in pretreated liquid milk products with high recoveries.

  18. Mirion--a software package for automatic processing of mass spectrometric images.

    Science.gov (United States)

    Paschke, C; Leisner, A; Hester, A; Maass, K; Guenther, S; Bouschen, W; Spengler, B

    2013-08-01

    Mass spectrometric imaging (MSI) techniques are of growing interest for the Life Sciences. In recent years, the development of new instruments employing ion sources that are tailored for spatial scanning allowed the acquisition of large data sets. A subsequent data processing, however, is still a bottleneck in the analytical process, as a manual data interpretation is impossible within a reasonable time frame. The transformation of mass spectrometric data into spatial distribution images of detected compounds turned out to be the most appropriate method to visualize the results of such scans, as humans are able to interpret images faster and easier than plain numbers. Image generation, thus, is a time-consuming and complex yet very efficient task. The free software package "Mirion," presented in this paper, allows the handling and analysis of data sets acquired by mass spectrometry imaging. Mirion can be used for image processing of MSI data obtained from many different sources, as it uses the HUPO-PSI-based standard data format imzML, which is implemented in the proprietary software of most of the mass spectrometer companies. Different graphical representations of the recorded data are available. Furthermore, automatic calculation and overlay of mass spectrometric images promotes direct comparison of different analytes for data evaluation. The program also includes tools for image processing and image analysis.

  19. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    International Nuclear Information System (INIS)

    Morgado, R.E.; Arnone, G.J.; Cappiello, C.C.

    1996-01-01

    A laboratory prototype system has been developed for the experimental evaluation of an explosives detection technique based on nuclear resonance absorption of gamma rays in nitrogen. Major subsystems include a radiofrequency quadrupole proton accelerator and associated beam transport system, a high-power gamma-ray production target, an airline-luggage tomographic inspection system, and an image- processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported

  20. Photometric and emission-spectrometric determination of boron in steels

    International Nuclear Information System (INIS)

    Thierig, D.

    1982-01-01

    A method for the photometric determination of boron in unalloyed and alloyed steels is described, in which Curcumine is used as reagent. A separation of boron is not necessary. Limit of detection: 0.0003% B. The decomposition of boron nitride in the steel is achieved by heating the whole sample in fuming sulphuric acid/phosphoric acid. For the emission spectrometric investigation of solid steel samples and for the spectrochemical analysis of solutions with plasma excitation working parameters are given and possibilities of interferences are demonstrated. (orig.) [de

  1. Quantitative analysis of flavonols, flavones, and flavanones in fruits, vegetables and beverages by high-performance liquid chromatography with photo-diode array and mass spectrometric detection

    DEFF Research Database (Denmark)

    Justesen, U.; Knuthsen, Pia; Leth, Torben

    1998-01-01

    after acid hydrolysis of freeze-dried food material. Identification was based on retention time, UV and mass spectra by comparison with commercial standards, and the UV peak areas were used for quantitation of the flavonoid contents. Examples of HPLC-MS analyses of orange pulp, tomato, and apple......A high-performance liquid chromatographic (HPLC) separation method viith photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages. The compounds were analysed as aglycones, obtained...

  2. On-line determination of manganese in solid seafood samples by flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Yebra, M.C.; Moreno-Cid, A.

    2003-01-01

    Manganese is extracted on-line from solid seafood samples by a simple continuous ultrasound-assisted extraction system (CUES). This system is connected to an on-line manifold, which permits the flow-injection flame atomic absorption spectrometric determination of manganese. Optimisation of the continuous leaching procedure is performed by an experimental design. The proposed method allows the determination of manganese with a relative standard deviation of 0.9% for a sample containing 23.4 μg g -1 manganese (dry mass). The detection limit is 0.4 μg g -1 (dry mass) for 30 mg of sample and the sample throughput is ca. 60 samples per hour. Accurate results are obtained by measuring TORT-1 certified reference material. The procedure is finally applied to mussel, tuna, sardine and clams samples

  3. Minicolumn field preconcentration and flow-injection flame atomic absorption spectrometric determination of cadmium in seawater

    International Nuclear Information System (INIS)

    Yebra-Biurrun, M.C.; Moreno-Cid, A.; Puig, L.

    2004-01-01

    A simple method for the continuous field preconcentration of trace dissolved cadmium in seawater samples has been developed based on the minicolumn field sampling technique. For this purpose, minicolumns containing Chelite P (aminomethylphosphonic groups) were connected to a field flow preconcentration system (FFPS). Once in the laboratory, these minicolumns are sequentially inserted into a flow-injection system for on-line cadmium elution and detection by flame atomic absorption spectrometry. Factorial designs have been used to optimise the FFPS and the flow-injection elution process. Six experimental variables were optimised: sample pH, sample flow-rate, eluent concentration, eluent volume, eluent flow-rate and minicolumn diameter. The detection limit (3F) of the procedure was 2.7 ng l -1 for a sample volume of 300 ml. The precision (expressed as relative standard deviation) for 11 independent determinations was 0.5-9.4% for cadmium solutions of 10-300 ng l -1 . Analysis of certified reference materials (SLEW-3 and NASS-5) showed good agreement with the certified values. This procedure has been successfully applied to the determination of cadmium in seawater samples from Galicia (Spain)

  4. Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

    International Nuclear Information System (INIS)

    Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A.; Landero-Figueroa, Julio

    2014-01-01

    The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV–VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag + ) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg −1 detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm

  5. Separation of silver ions and starch modified silver nanoparticles using high performance liquid chromatography with ultraviolet and inductively coupled mass spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Hanley, Traci A.; Saadawi, Ryan; Zhang, Peng; Caruso, Joseph A., E-mail: joseph.caruso@uc.edu; Landero-Figueroa, Julio

    2014-10-01

    The production of commercially available products marketed to contain silver nanoparticles is rapidly increasing. Species-specific toxicity is a phenomenon associated with many elements, including silver, making it imperative to develop a method to identify and quantify the various forms of silver (namely, silver ions vs. silver nanoparticles) possibly present in these products. In this study a method was developed using high performance liquid chromatography (HPLC) with ultraviolet (UV–VIS) and inductively coupled mass spectrometric (ICP-MS) detection to separate starch stabilized silver nanoparticles (AgNPs) and silver ions (Ag{sup +}) by cation exchange chromatography with 0.5 M nitric acid mobile phase. The silver nanoparticles and ions were baseline resolved with an ICP-MS response linear over four orders of magnitude, 0.04 mg kg{sup −1} detection limit, and 90% chromatographic recovery for silver solutions containing ions and starch stabilized silver nanoparticles smaller than 100 nm.

  6. Detection of atomic oxygen in flames by absorption spectroscopy

    International Nuclear Information System (INIS)

    Cheskis, S.; Kovalenko, S.A.

    1994-01-01

    The absolute concentration of atomic oxygen in an atmospheric pressure hydrogen/air flame has been measured using Intracavity Laser Spectroscopy (ICLS) based on a dye laser pumped by an argon-ion laser. Absorptions at the highly forbidden transitions at 630.030 nm and 636.380 nm were observed at an equivalent optical length of up to 10 km. The relatively low intensity of the dye laser avoids photochemical interferences that are inherent to some other methods for detecting atomic oxygen. The detection sensitivity is about 6x10 14 atom/cm 3 and can be improved with better flame and laser stabilization. (orig.)

  7. Anti-aggregation-based spectrometric detection of Hg(II) at physiological pH using gold nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Rajeshwari, A.; Karthiga, D.; Chandrasekaran, Natarajan; Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com

    2016-10-01

    An efficient detection method for Hg (II) ions at physiological pH (pH 7.4) was developed using tween 20-modified gold nanorods (NRs) in the presence of dithiothreitol (DTT). Thiol groups (-SH) at the end of DTT have a higher affinity towards gold atoms, and they can covalently interact with gold NRs and leads to their aggregation. The addition of Hg(II) ions prevents the aggregation of gold NRs due to the covalent bond formation between the -SH group of DTT and Hg(II) ions in the buffer system. The changes in the longitudinal surface plasmon resonance peak of gold NRs were characterized using a UV–visible spectrophotometer. The absorption intensity peak of gold NRs at 679 nm was observed to reduce after interaction with DTT, and the absorption intensity was noted to increase by increasing the concentration of Hg(II) ions. The TEM analysis confirms the morphological changes of gold NRs before and after addition of Hg(II) ions in the presence of DTT. Further, the aggregation and disaggregation of gold NRs were confirmed by particle size and zeta potential analysis. The developed method shows an excellent linearity (y = 0.001 x + 0.794) for the graph plotted between the absorption ratio and Hg(II) concentration (1 to 100 pM) under the optimized conditions. The limit of detection was noted to be 0.42 pM in the buffer system. The developed method was tested in simulated body fluid, and it was found to have a good recovery rate. - Highlights: • Tween-20 modified gold NRs used as a probe for Hg(II) at physiological pH. • TEM, particle size and surface charge analysis confirm the aggregation and • disaggregation of NRs • The sensitivity of the probe for Hg(II) ions detection was 0.42 pM. • Hg(II) estimation in simulated body fluids with good recovery.

  8. Molecular detection with terahertz waves based on absorption-induced transparency metamaterials

    Science.gov (United States)

    G. Rodrigo, Sergio; Martín-Moreno, L.

    2016-10-01

    A system for the detection of spectral signatures of chemical compounds at the Terahertz regime is presented. The system consists on a holey metal film whereby the presence of a given substance provokes the appearance of spectral features in transmission and reflection induced by the molecular specimen. These induced effects can be regarded as an extraordinary optical transmission phenomenon called absorption-induced transparency (AIT). The phenomenon consist precisely in the appearance of peaks in transmission and dips in reflection after sputtering of a chemical compound onto an initially opaque holey metal film. The spectral signatures due to AIT occur unexpectedly close to the absorption energies of the molecules. The presence of a target, a chemical compound, would be thus revealed as a strong drop in reflectivity measurements. We theoretically predict the AIT based system would serve to detect amounts of hydrocyanic acid (HCN) at low rate concentrations.

  9. Valence-to-core-detected X-ray absorption spectroscopy

    DEFF Research Database (Denmark)

    Hall, Eleanor R.; Pollock, Christopher J.; Bendix, Jesper

    2014-01-01

    X-ray absorption spectroscopy (XAS) can provide detailed insight into the electronic and geometric structures of transition-metal active sites in metalloproteins and chemical catalysts. However, standard XAS spectra inherently represent an average contribution from the entire coordination...... environment with limited ligand selectivity. To address this limitation, we have investigated the enhancement of XAS features using valence-to-core (VtC)-detected XAS, whereby XAS spectra are measured by monitoring fluorescence from valence-to-core X-ray emission (VtC XES) events. VtC emission corresponds...... to transitions from filled ligand orbitals to the metal 1s core hole, with distinct energetic shifts for ligands of differing ionization potentials. VtC-detected XAS data were obtained from multiple valence emission features for a series of well-characterized Mn model compounds; taken together, these data...

  10. The fast gamma spectrometric method of the Am-241 determination in Chernobyl restricted zone soils

    International Nuclear Information System (INIS)

    Gleisberg, B.; Lukachina, V.V.; Kirsenko, V.N.; Tepikin, V.E.; Rajevsky, V.S.; Libman, V.A.; Stoljarevsky, I.P.; Isajev, A.G.

    1997-01-01

    The known methods of the 241 Am contents determination in environmental objects, as a rule, is based on ion-chromatographic or extraction separation techniques. This approach reflects widespread opinion, that only the α-spectrometric analysis termination is suitable to ensure necessary sensitivity of the overall method of 241 Am actively determination. Really, the minimal detectable activity for such methods is about 0.05 Bq/kg (considering that Am is usually concentrated during separation procedure). However, because of α-spectrometry does not permit to separate the α-peaks of the 241 Am, and 238 Pu, but also in view of high requests to the α-spectrometric specimen purity, the multistage and laborious chemical procedures to separate 241 Am from plutonium radionuclides and other elements (with a thorough control of each separation stage) are needed

  11. The use of car-borne gamma-ray spectrometric survey in a basin

    International Nuclear Information System (INIS)

    Liu Tengyao; Lu Shili; Luo Zongquan.

    1985-01-01

    This paper describes the geological results in a basin in the Inner Mongolia which were obtained by using our newly-developed and assembled car-borne gamma-ray spectrometric system. Combined with the work of regional geology and remote sensing, five relatively favourable uranium zones were located within the working area. The field procedures of car-borne gamma-ray spectrometry for less rigid regions is discussed. The gamma-ray spectrometric profiling is mainly used for regional reconnaissance. In the case of enhanced anomalious radioactivity the profiling with varying directions is adopted and the data are plotted on scale 1:50000 topographic map. It is suggested that the car-borne gamma-ray spectrometric system can be calibrated both by the pads specified for portable spectrometers and by testing site when the calibration facility for the car-borne gamma-ray spectrometric system is not available. The effect of rainfall on car-borne gamma-ray spectrometric survey and the simplified field qualitative determination of U-Ra disequilibrium are also briefly discussed

  12. Surfactant/oil/water system for the determination of selenium in eggs by graphite furnace atomic absorption spectrometry

    Science.gov (United States)

    Ieggli, C. V. S.; Bohrer, D.; Noremberg, S.; do Nascimento, P. C.; de Carvalho, L. M.; Vieira, S. L.; Reis, R. N.

    2009-06-01

    An oil-in-water formulation has been optimized to determine trace levels of selenium in whole hen eggs by graphite furnace atomic absorption spectrometry. This method is simpler and requires fewer reagents when compared with other sample pre-treatment procedures. Graphite furnace atomic absorption spectrometric (GF AAS) measurement was carried out using standard addition calibration and Pd as a modifier. The precision, expressed as relative standard deviation, was better than 5% and the limit of detection was 1 µg L - 1 . The validation of the method was performed against a standard reference material Whole Egg Powder (RM 8415), and the measured Se corresponded to 95.2% of the certified value. The method was used for the determination of the Se level in eggs from hens treated with Se dietary supplements. Inorganic and organic Se sources were added to hen feed. The Se content of eggs was higher when hens were fed with organic Se compared to the other treatments. The proposed method, including sample emulsification for subsequent Se determination by GF AAS has proved to be sensitive, reproducible, simple and economical.

  13. Surfactant/oil/water system for the determination of selenium in eggs by graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ieggli, C.V.S. [Departamento de Quimica, Avenida Roraima, 1000, Universidade Federal de Santa Maria, CEP 97110-970, Santa Maria, RS (Brazil); Bohrer, D. [Departamento de Quimica, Avenida Roraima, 1000, Universidade Federal de Santa Maria, CEP 97110-970, Santa Maria, RS (Brazil)], E-mail: ndenise@quimica.ufsm.br; Noremberg, S.; Nascimento, P.C. do; Carvalho, L.M. de [Departamento de Quimica, Avenida Roraima, 1000, Universidade Federal de Santa Maria, CEP 97110-970, Santa Maria, RS (Brazil); Vieira, S.L.; Reis, R.N. [Faculdade de Agronomia, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves, 7712, CEP 90540-000, Porto Alegre (Brazil)

    2009-06-15

    An oil-in-water formulation has been optimized to determine trace levels of selenium in whole hen eggs by graphite furnace atomic absorption spectrometry. This method is simpler and requires fewer reagents when compared with other sample pre-treatment procedures. Graphite furnace atomic absorption spectrometric (GF AAS) measurement was carried out using standard addition calibration and Pd as a modifier. The precision, expressed as relative standard deviation, was better than 5% and the limit of detection was 1 {mu}g L{sup - 1}. The validation of the method was performed against a standard reference material Whole Egg Powder (RM 8415), and the measured Se corresponded to 95.2% of the certified value. The method was used for the determination of the Se level in eggs from hens treated with Se dietary supplements. Inorganic and organic Se sources were added to hen feed. The Se content of eggs was higher when hens were fed with organic Se compared to the other treatments. The proposed method, including sample emulsification for subsequent Se determination by GF AAS has proved to be sensitive, reproducible, simple and economical.

  14. Processing of gamma-ray spectrometric logs

    International Nuclear Information System (INIS)

    Umiastowski, K.; Dumesnil, P.

    1984-10-01

    CEA (Commissariat a l'Energie Atomique) has developped a gamma-ray spectrometric tool, containing an analog-to-digital converter. This new tool permits to perform very precise uranium logs (natural gamma-ray spectrometry), neutron activation logs and litho-density logs (gamma-gamma spectrometric logs). Specific processing methods were developped to treate the particular problems of down-hole gamma-ray spectrometry. Extraction of the characteristic gamma-ray peak, even if they are superposed on the background radiation of very high intensity, is possible. This processing methode enables also to obtain geological informations contained in the continuous background of the spectrum. Computer programs are written in high level language for SIRIUS (VICTOR) and APOLLO computers. Exemples of uranium and neutron activation logs treatment are presented [fr

  15. Increased Protein Structural Resolution from Diethylpyrocarbonate-based Covalent Labeling and Mass Spectrometric Detection

    Science.gov (United States)

    Zhou, Yuping; Vachet, Richard W.

    2012-04-01

    Covalent labeling and mass spectrometry are seeing increased use together as a way to obtain insight into the 3-dimensional structure of proteins and protein complexes. Several amino acid specific (e.g., diethylpyrocarbonate) and non-specific (e.g., hydroxyl radicals) labeling reagents are available for this purpose. Diethylpyrocarbonate (DEPC) is a promising labeling reagent because it can potentially probe up to 30% of the residues in the average protein and gives only one reaction product, thereby facilitating mass spectrometric analysis. It was recently reported, though, that DEPC modifications are labile for some amino acids. Here, we show that label loss is more significant and widespread than previously thought, especially for Ser, Thr, Tyr, and His residues, when relatively long protein digestion times are used. Such label loss ultimately decreases the amount of protein structural information that is obtainable with this reagent. We find, however, that the number of DEPC modified residues and, thus, protein structural information, can be significantly increased by decreasing the time between the covalent labeling reaction and the mass spectrometric analysis. This is most effectively accomplished using short (e.g., 2 h) proteolytic digestions with enzymes such as immobilized chymotrypsin or Glu-C rather than using methods (e.g., microwave or ultrasonic irradiation) that accelerate proteolysis in other ways. Using short digestion times, we show that the percentage of solvent accessible residues that can be modified by DEPC increases from 44% to 67% for cytochrome c, 35% to 81% for myoglobin, and 76% to 95% for β-2-microglobulin. In effect, these increased numbers of modified residues improve the protein structural resolution available from this covalent labeling method. Compared with typical overnight digestion conditions, the short digestion times decrease the average distance between modified residues from 11 to 7 Å for myoglobin, 13 to 10 Å for

  16. The downfall of TBA-354 - a possible explanation for its neurotoxicity via mass spectrometric imaging.

    Science.gov (United States)

    Ntshangase, Sphamandla; Shobo, Adeola; Kruger, Hendrik G; Asperger, Arndt; Niemeyer, Dagmar; Arvidsson, Per I; Govender, Thavendran; Baijnath, Sooraj

    2017-10-13

    1. TBA-354 was a promising antitubercular compound with activity against both replicating and static Mycobacterium tuberculosis (M.tb), making it the focal point of many clinical trials conducted by the TB Alliance. However, findings from these trials have shown that TBA-354 results in mild signs of reversible neurotoxicity; this left the TB Alliance with no other choice but to stop the research. 2. In this study, mass spectrometric methods were used to evaluate the pharmacokinetics and spatial distribution of TBA-354 in the brain using a validated liquid chromatography tandem-mass spectrometry (LCMS/MS) and mass spectrometric imaging (MSI), respectively. Healthy female Sprague-Dawley rats received intraperitoneal (i.p.) doses of TBA-354 (20 mg/kg bw). 3. The concentrationtime profiles showed a gradual absorption and tissue penetration of TBA-354 reaching the C max at 6 h post dose, followed by a rapid elimination. MSI analysis showed a time-dependent drug distribution, with highest drug concentration mainly in the neocortical regions of the brain. 4. The distribution of TBA-354 provides a possible explanation for the motor dysfunction observed in clinical trials. These results prove the importance of MSI as a potential tool in preclinical evaluations of suspected neurotoxic compounds.

  17. A system design of gamma-ray spectrometric data processing for gold prospecting

    International Nuclear Information System (INIS)

    Yin Xueqin; Cheng Xuchu; Fang Lianxi; Huang Zuofeng.

    1992-01-01

    Based on different correlation between gamma-ray spectrometric data and gold grade in different types of gold deposits, it is necessary and possible to establish a mathematical model of gamma-ray spectrometric data processing for predicting specific gold deposits. A system design of gamma-ray spectrometric data processing for prospecting gold deposits has been worked out according to the mathematical method and procedure of data processing. The prediction effectiveness of commonly used multiple linear regression analysis is always not ideal but regression accuracy will be evidently increased after pre-processing of the calculated weight, deviation and favorability on gamma-ray spectrometric data. This system can establish more than ten models at the same time which enable users to have more choice. Tree structure and Chinese menu prompting are adopted in this system which can be utilized separately, sub-systems at different levels can be also individually operated. It can be transplanted to data processing of other similar geological deposit models (including non-gamma ray spectrometric data). The system is rapid, accurate, simple, convenient and flexible in use, more practical and easily popularized

  18. A CCD-based system for the detection of DNA in electrophoresis gels by UV absorption

    International Nuclear Information System (INIS)

    Mahon, A.R.; MacDonald, J.H.; Mainwood, A.; Ott, R.J.

    1999-01-01

    A method and apparatus for the detection and quantification of large fragments of unlabelled nucleic acids in agarose gels is presented. The technique is based on ultraviolet (UV) absorption by nucleotides. A deuterium source illuminates individual sample lanes of an electrophoresis gel via an array of optical fibres. As DNA bands pass through the illuminated region of the gel the amount of UV light transmitted is reduced because of absorption by the DNA. During electrophoresis the regions of DNA are detected on-line using a UV-sensitive charge coupled device (CCD). As the absorption coefficient is proportional to the mass of DNA the technique is inherently quantitative. The mass of DNA in a region of the gel is approximately proportional to the integrated signal in the corresponding section of the CCD image. This system currently has a detection limit of less than 1.25 ng compared with 2-10 ng for the most popular conventional technique, ethidium bromide (EtBr) staining. In addition the DNA sample remains in its native state. The removal of the carcinogenic dye from the detection procedure greatly reduces associated biological hazards. (author)

  19. Marine gamma spectrometric survey

    International Nuclear Information System (INIS)

    Kostoglodov, V.V.

    1979-01-01

    Presented are theoretical problems physical and geochemical prerequisites and possibilities of practical application of the method of continuous submarine gamma-spectrometric survey and radiometric survey destined for rapid study of the surface layer of marine sediments. Shown is high efficiency and advantages of this method in comparison with traditional and widely spread in marine geology methods of bottom sediments investigation

  20. Absorption of human skin and its detecting platform in the process of laser cosmetology

    Science.gov (United States)

    Zhang, Yong-Lin; Ouyang, Li; Wang, Yang

    2000-10-01

    Because of the melanin, hemoglobin and water molecules, etc. contained, light absorption of human skin tissue changes with wavelength of light. This is the principle used in laser cosmetology for treating pigment diseases and vascular lesion diseases as well as skin decoration such as body tattooing, eyebrow tattooing, etc. The parameters of treatment used in laser cosmetology principally come from the research of the skin tissue optical characteristics of whites, and it is not suitable for the Oriental. The absorption spectrum of yellow race alive skin has been researched. The detecting platform for use in the measuring of vivi-tissue absorption spectrum has been developed which using opto-electronic nondestructive testing and virtual instrument techniques. The degree of pathological changes of skin can be detected by this platform also, thus the shortcoming of dosage selection in laser clinical treatments which have been decided only by naked eye observation and past experience of doctors can be solved.

  1. Detection of the Galactic Warm Neutral Medium in HI 21cm absorption

    Science.gov (United States)

    Patra, Narendra Nath; Kanekar, Nissim; Chengalur, Jayaram N.; Roy, Nirupam

    2018-05-01

    We report a deep Giant Metrewave Radio Telescope (GMRT) search for Galactic HI 21cm absorption towards the quasar B0438-436, yielding the detection of wide, weak HI 21cm absorption, with a velocity-integrated HI 21cm optical depth of 0.0188 ± 0.0036 km s-1. Comparing this with the HI column density measured in the Parkes Galactic All-Sky Survey gives a column density-weighted harmonic mean spin temperature of 3760 ± 365 K, one of the highest measured in the Galaxy. This is consistent with most of the HI along the sightline arising in the stable warm neutral medium (WNM). The low peak HI 21cm optical depth towards B0438-436 implies negligible self-absorption, allowing a multi-Gaussian joint decomposition of the HI 21cm absorption and emission spectra. This yields a gas kinetic temperature of T_k ≤ (4910 ± 1900) K, and a spin temperature of T_s = (1000 ± 345) K for the gas that gives rise to the HI 21cm absorption. Our data are consistent with the HI 21cm absorption arising from either the stable WNM, with T_s ≪ T_k, T_k ≈ 5000 K, and little penetration of the background Lyman-α radiation field into the neutral hydrogen, or from the unstable neutral medium, with T_s ≈ T_k ≈ 1000K.

  2. A spectrometric approach in radiography for detection of materials by their effective atomic number

    CERN Document Server

    Ryzhikov, V D; Onyshchenko, G M; Lecoq, P; Smith, C F

    2009-01-01

    In this paper we report a spectrometric approach to dual-energy digital radiography that has been developed and applied to identify specific organic substances and discern small differences in their effective atomic number. An experimental setup has been designed, and a theoretical description proposed based on the experimental results obtained. The proposed method is based on the application of special reference samples made of materials with different effective atomic number and thickness parameters known to affect X-ray attenuation in the low-energy range. The results obtained can be used in the development of a new generation of multi-energy customs or medical X-ray scanners.

  3. 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)

  4. Quantitative determination of plant phenolics in Urtica dioica extracts by high-performance liquid chromatography coupled with tandem mass spectrometric detection.

    Science.gov (United States)

    Orčić, Dejan; Francišković, Marina; Bekvalac, Kristina; Svirčev, Emilija; Beara, Ivana; Lesjak, Marija; Mimica-Dukić, Neda

    2014-01-15

    A method for quantification of 45 plant phenolics (including benzoic acids, cinnamic acids, flavonoid aglycones, C- and O-glycosides, coumarins, and lignans) in plant extracts was developed, based on reversed phase HPLC separation of extract components, followed by tandem mass spectrometric detection. The phenolic profile of 80% MeOH extracts of the stinging nettle (Urtica dioica L.) herb, root, stem, leaf and inflorescence was obtained by using this method. Twenty-one of the investigated compounds were present at levels above the reliable quantification limit, with 5-O-caffeoylquinic acid, rutin and isoquercitrin as the most abundant. The inflorescence extracts were by far the richest in phenolics, with the investigated compounds amounting 2.5-5.1% by weight. As opposed to this, the root extracts were poor in phenolics, with only several acids and derivatives being present in significant amounts. The results obtained by the developed method represent the most detailed U. dioica chemical profile so far. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Determination of itopride in human plasma by liquid chromatography coupled to tandem mass spectrometric detection: application to a bioequivalence study.

    Science.gov (United States)

    Lee, Heon-Woo; Seo, Ji-Hyung; Choi, Seung-Ki; Lee, Kyung-Tae

    2007-01-30

    A simple method using a one-step liquid-liquid extraction (LLE) with butyl acetate followed by high-performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometric (ESI-MS/MS) detection was developed for the determination of itopride in human plasma, using sulpiride as an internal standard (IS). Acquisition was performed in multiple reaction monitoring (MRM) mode, by monitoring the transitions: m/z 359.5>166.1 for itopride and m/z 342.3>111.6 for IS, respectively. Analytes were chromatographed on an YMC C18 reverse-phase chromatographic column by isocratic elution with 1 mM ammonium acetate buffer-methanol (20: 80, v/v; pH 4.0 adjusted with acetic acid). Results were linear (r2=0.9999) over the studied range (0.5-1000 ng mL(-1)) with a total analysis time per run of 2 min for LC-MS/MS. The developed method was validated and successfully applied to bioequivalence studies of itopride hydrochloride in healthy male volunteers.

  6. Spectrometric techniques 2

    CERN Document Server

    Vanasse, George A

    2013-01-01

    Spectrometric Techniques, Volume II provides information pertinent to vacuum ultraviolet techniques to complete the demonstration of the diversity of methods available to the spectroscopist interested in the ultraviolet visible and infrared spectral regions. This book discusses the specific aspects of the technique of Fourier transform spectroscopy.Organized into five chapters, this volume begins with an overview of the large number of systematic effects in the recording of an interferogram. This text then examines the design approach for a Fourier transform spectrometer with focus on optics.

  7. Gamma Spectrometric Determination of U, Th, K and Some Geochemical Applications

    International Nuclear Information System (INIS)

    Dodona, A.; Tashko, A.

    2001-01-01

    The application of 'in situ' gamma-spectrometric method (''infinite'' environment), made possible the simultanious determination of U, Th and K. 4 channel gamma-spectrometric analyser with NaI(TI) scintilation counter crystal detector (103 cm 3 φ=50x50mm) was used to determin U, Th(more than 1-2 ppm) and K (more than 1%) in laboratory conditions. The detector was inserted into a lead camera and calibrated for measurement geometry with vessel of ''Marineli'' type of a 17o cm 3 volume. The study of main factors, which influence in the gamma spectrometric measurements, (the technical, physical, geometrical and time parameters) has been carried out. International standards of U, Th, K and internal monitoring standard samples are used for the calibration. External analytical control has been realized by other radiometric and chemical methods. The detection limits ( 1 ppm Th, 2ppm U and 1% K) and the relative errors (17-20% for 1-10 ppm U, Th and 10-15% for more than 10 ppm U, Th and more than 1% K) guarantee a quantitative analysis that may be used successfully in the geochemical studies. Some geochemical applications, based on the content of Th, U and Th/U ratio in rocks samples that we have we have analyzed with this method, are shown in this paper. U, Th and their ratio are used as trace elements to indicate the differences between the acidic magmatic rocks of Albania (Th/U ratio=2-6 and>10). The bimodal character of Th/U scattering in ignimbrides and monzonites (Korabi zone) shows that in addition to the ''normal'' rocks, there are also some ones enriched with Th, So, the differential analysis of Th, U, and K may be used as geochemical exploration criteria for the radioactive and non-radioactive mineralization, such as REE (Rare Earth Elements), phospghorites, bauxites, placers etc. (authors)

  8. Development of a real-time absorption method for detecting the mercaptan odorizing mixture of natural gas

    NARCIS (Netherlands)

    Kireev, SV; Petrov, NG; Podolyako, EM; Shnyrev, SL

    The absorption of mercaptan mixtures used for odorizing natural gas and mixtures of natural gas is experimentally studied in the spectral range 2.5-20 mu m. An absorption method for the real-time detection of the odorant concentration is proposed. The method is based on intensity measurements of the

  9. Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

    African Journals Online (AJOL)

    HP

    Original Research Article. Gas Chromatography-Mass Spectrometric Analysis and ... into a natural fumigant/insecticide for the control of stored product insects. Keywords: Mallotus ..... stability as well as reduce cost. ACKNOWLEDGEMENT.

  10. Commercial Applications of X Ray Spectrometric Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Wegrzynek, D., E-mail: D.Wedgrznek@iaea.org [International Atomic Energy Agency, The IAEA Laboratories, Seibersdorf, Vienna (Austria)

    2013-07-15

    In the 21st century, the X-ray fluorescence (XRF) technique is widely used in process control, industrial applications and for routine elemental analysis. The technique has a multielement capability capable of detecting elements with Z {>=} 10, with a few instruments capable of detecting also elements with Z {>=} 5. It is characterized by a non-destructive analysis process and relatively good detection limits, typically one part per million, for a wide range of elements. The first commercial XRF instruments were introduced to the market about 50 years ago. They were the wavelength dispersive X ray fluorescence (WDXRF) spectrometers utilizing Bragg's law and reflection on crystal lattices for sequential elemental analysis of sample composition. The advances made in radiation detector technology, especially the introduction of semiconductor detectors, improvements in signal processing electronics, availability and exponential growth of personal computer market led to invention of energy dispersive X ray fluorescence (EDXRF) technique. The EDXRF is more cost effective as compared to WDXRF. It also allows for designing compact instruments. Such instruments can be easily tailored to the needs of different customers, integrated with industrial installations, and also miniaturized for the purpose of in-situ applications. The versatility of the technique has been confirmed in a spectacular way by using the XRF and X-ray spectrometric techniques, among few others, during the NASA and ESA missions in search for the evidence of life and presence of water on the surface of Mars. The XRF technique has achieved its strong position within the atomic spectroscopy group of analytical techniques not only due to its versatility but also due to relatively low running costs, as compared to the commonly used methods, e.g., atomic absorption spectrometry (AAS) or inductively coupled plasma atomic emission/mass spectrometry (ICP-AES/MS). Presently, the XRF technique together with X ray

  11. [Gas pipeline leak detection based on tunable diode laser absorption spectroscopy].

    Science.gov (United States)

    Zhang, Qi-Xing; Wang, Jin-Jun; Liu, Bing-Hai; Cai, Ting-Li; Qiao, Li-Feng; Zhang, Yong-Ming

    2009-08-01

    The principle of tunable diode laser absorption spectroscopy and harmonic detection technique was introduced. An experimental device was developed by point sampling through small multi-reflection gas cell. A specific line near 1 653. 7 nm was targeted for methane measurement using a distributed feedback diode laser as tunable light source. The linearity between the intensity of second harmonic signal and the concentration of methane was determined. The background content of methane in air was measured. The results show that gas sensors using tunable diode lasers provide a high sensitivity and high selectivity method for city gas pipeline leak detection.

  12. Airborne Measurements of CO2 Column Absorption and Range Using a Pulsed Direct-Detection Integrated Path Differential Absorption Lidar

    Science.gov (United States)

    Abshire, James B.; Riris, Haris; Weaver, Clark J.; Mao, Jianping; Allan, Graham R.; Hasselbrack, William E.; Browell, Edward V.

    2013-01-01

    We report on airborne CO2 column absorption measurements made in 2009 with a pulsed direct-detection lidar operating at 1572.33 nm and utilizing the integrated path differential absorption technique. We demonstrated these at different altitudes from an aircraft in July and August in flights over four locations in the central and eastern United States. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The lidar measurement statistics were also calculated for each flight as a function of altitude. The optical depth varied nearly linearly with altitude, consistent with calculations based on atmospheric models. The scatter in the optical depth measurements varied with aircraft altitude as expected, and the median measurement precisions for the column varied from 0.9 to 1.2 ppm. The altitude range with the lowest scatter was 810 km, and the majority of measurements for the column within it had precisions between 0.2 and 0.9 ppm.

  13. Force-detected nanoscale absorption spectroscopy in water at room temperature using an optical trap

    Science.gov (United States)

    Parobek, Alexander; Black, Jacob W.; Kamenetska, Maria; Ganim, Ziad

    2018-04-01

    Measuring absorption spectra of single molecules presents a fundamental challenge for standard transmission-based instruments because of the inherently low signal relative to the large background of the excitation source. Here we demonstrate a new approach for performing absorption spectroscopy in solution using a force measurement to read out optical excitation at the nanoscale. The photoinduced force between model chromophores and an optically trapped gold nanoshell has been measured in water at room temperature. This photoinduced force is characterized as a function of wavelength to yield the force spectrum, which is shown to be correlated to the absorption spectrum for four model systems. The instrument constructed for these measurements combines an optical tweezer with frequency domain absorption spectroscopy over the 400-800 nm range. These measurements provide proof-of-principle experiments for force-detected nanoscale spectroscopies that operate under ambient chemical conditions.

  14. First Time Rapid and Accurate Detection of Massive Number of Metal Absorption Lines in the Early Universe Using Deep Neural Network

    Science.gov (United States)

    Zhao, Yinan; Ge, Jian; Yuan, Xiaoyong; Li, Xiaolin; Zhao, Tiffany; Wang, Cindy

    2018-01-01

    Metal absorption line systems in the distant quasar spectra have been used as one of the most powerful tools to probe gas content in the early Universe. The MgII λλ 2796, 2803 doublet is one of the most popular metal absorption lines and has been used to trace gas and global star formation at redshifts between ~0.5 to 2.5. In the past, machine learning algorithms have been used to detect absorption lines systems in the large sky survey, such as Principle Component Analysis, Gaussian Process and decision tree, but the overall detection process is not only complicated, but also time consuming. It usually takes a few months to go through the entire quasar spectral dataset from each of the Sloan Digital Sky Survey (SDSS) data release. In this work, we applied the deep neural network, or “ deep learning” algorithms, in the most recently SDSS DR14 quasar spectra and were able to randomly search 20000 quasar spectra and detect 2887 strong Mg II absorption features in just 9 seconds. Our detection algorithms were verified with previously released DR12 and DR7 data and published Mg II catalog and the detection accuracy is 90%. This is the first time that deep neural network has demonstrated its promising power in both speed and accuracy in replacing tedious, repetitive human work in searching for narrow absorption patterns in a big dataset. We will present our detection algorithms and also statistical results of the newly detected Mg II absorption lines.

  15. Gas Chromatography-Mass Spectrometric Analysis of Nematicidal ...

    African Journals Online (AJOL)

    Gas Chromatography-Mass Spectrometric Analysis of Nematicidal Essential Oil of Valeriana ... Tropical Journal of Pharmaceutical Research ... have a potential to be developed to natural nematicides for the control of cereal cyst nematodes.

  16. Spectrometric control of radionuclides production parameters

    International Nuclear Information System (INIS)

    Zhuk, I.; Potarenko, A.; Yarochevich, O.; Hluboky, N.; Kerko, P.; Bogdanov, V.; Dyatel, N.

    2006-01-01

    Full text: A radioactive preparations and sources are widely used all over the world for scientific, industrial and medical purposes. These preparations in Belarus are planned to produce by the Joint Belarussian-Russian Closed Joint Stock Company 'Isotope technologies' (CJSC IT). The company was created in 1998 by two leading scientific centers-SSI 'Joint Institute of Power and Nuclear Research-Sosny' the National Academy of Sciences of Belarus and the State Center of Science of the Russian Federation 'Scientific research institute of nuclear reactors'. One of the mainstream directions in CJSC IT activities is production of radioactive preparations for the industrial and scientific application (such as 133 Ba, 109 Cd, 63 Ni, 60 Co) and for the medical purposes (such as 19 '2Ir, 60 Co). All radioactive preparations have a good export potential and adequate to modern technical and consumer requirements. X-γ spectrometric analysis of considered radioactive sources is one of the basic methods for quality control of radioactive sources. At present, we are developing x-γ spectrometric support of purification process from contaminating radionuclides of 109 Cd -γ preparation and 63 Ni - β preparation. Work on x-γ spectrometric quality control of 133 Ba preparation is carried out. The description of the used equipment is given. Techniques of contaminating radionuclides determination (contents ∼10 - '6 from activity of the basic radionuclide) are presented. Problems of the choice of geometry of measurements of sources with activity about 10 7 -10 9 Bq and possible sources of errors are discussed. (author)

  17. Levelling Airborne and Ground Gamma-Ray Spectrometric Data to Assist Uranium Exploration

    Energy Technology Data Exchange (ETDEWEB)

    Matolin, M., E-mail: matolin@natur.cuni.cz [Charles University, Prague (Czech Republic); Minty, B. [Geoscience Australia, Canberra (Australia)

    2014-05-15

    Geophysical methods can be used for mapping in both 2 and 3 dimensions, as well as the direct detection of ore bodies. The gamma-ray spectrometric method is an efficient method for the regional assessment of uranium potential and the detection of surface mineralization. However, the full potential of the method can only be realized when the data are adequately standardized. Examples of this standardization at both regional and local scales are dealt in this paper. At a regional scale, it is shown how the levelling of airborne gamma-ray spectrometry data over Australia increases the value of the resulting data, and on a local scale a geometrical correction for ground gamma-ray spectrometry in shallow holes that improves the accuracy of measurements is introduced. (author)

  18. Rational utilisation of a spectrometer detector for leaks; Utilisation rationnelle d'un spectrometre detecteur de fuites

    Energy Technology Data Exchange (ETDEWEB)

    Geller, R [Commissariat a l' Energie Atomique, Saclay(France). Centre d' Etudes Nucleaires

    1954-07-01

    In this following article, we expose the general problem of the leakage in a vacuum installation. We consider the principles of the detection in general and study especially the conditions of detection by an helium spectrometer. We deduce practical conclusions as for the branching of this last and to its application in the most current cases. (author) [French] Dans l'article qui suit, nous exposons le probleme general des fuites dans une installation a vide. Nous y envisageons les principes de la detection en general et etudions particulierement les conditions de detection par spectrometre a helium. Noue tirons des conclusions pratiques quant au branchement de ce dernier et a son application dans les cas les plus courants. (auteur)

  19. Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research ... apelta aerial parts was analyzed by gas chromatography/mass spectrometric (GC/MS) to determine its composition. ... into a natural fumigant/insecticide for the control of stored product insects.

  20. The composition of bile acids in patients with cholelithiasis according to the data of liquid chromatography with mass spectrometric detection

    Directory of Open Access Journals (Sweden)

    V. M. Klymenko

    2017-12-01

    Full Text Available Bile acids play a leading role in the physical and colloidal properties of bile stabilization. Lack of bile acids consequences result in the formation of cholesterol stones in the gall bladder, diarrhea and steatorrhea, fat-soluble vitamins impaired absorption, and kidney stones formation (oxalates. Investigation of altered bile composition, especially the content of bile acids, in patients with gallstone disease by means of modern analytical analysis methods (liquid chromatography with mass spectrometric detection would complement the modern ideas about mechanisms of lithogenesis and aim efforts at prevention of stone formation in the gall bladder, that was the purpose of our work. Materials and methods. Bile samples were tested for bile acid content using liquid chromatography with mass spectrometry. 14 samples of bile from patients with cholelithiasis were included in the main group, and control group consisted of 7 bile samples from practically healthy persons. Results. In patients with cholelithiasis there is an increase in the content of conjugated forms of bile acids – glycolic acid in 2 times (p = 0.002, taurocholic acid in 1.57 times (p = 0.062 compared with practically healthy persons. In patients with cholelithiasis, the ratio of taurocholic to glycolic acidі content (0.95 vs. 1.27, p = 0.0179, as well as glycogenodeoxycholic to glycodeoxycholic acid (1.11 vs. 1.58, p = 0.027 is significantly less than that in practically healthy persons. In addition, one in two patients with cholelithiasis does not reveal the presence of ursodeoxycholic acid in the bile. Conclusions. The lithogenic properties of bile are primarily caused by conjugated forms of cholic acid with glycine and taurine content violation. The ratio of taurocholic to glycolic acid content in patients with cholelithiasis is significantly lower than the similar index in practically healthy persons (0.95 vs. 1.27, p = 0.0179. The ratio of glycine conjugated bile acids

  1. Speciation of four selenium compounds using high performance liquid chromatography with on-line detection by inductively coupled plasma mass spectrometry or flame atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Pedersen, Gitte Alsing; Larsen, Erik Huusfeldt

    1997-01-01

    An analytical method for the speciation of selenomethionine, selenocystine, selenite and selenate by high performance liquid chromatography (HPLC) with atomic spectrometric detection is presented. An organic polymeric strong anion exchange column was used as the stationary phase in combination...... spectrometry (ICP-MS). The signal-to-noise ratio of the FAAS detector was optimized using a hydrogen-argon entrained-air flame and a slotted-tube atom trap (STAT) in the flame. The limit of detection (3 sigma) achieved by the HPLC-FAAS system was 1 mg L-1 of selenium (100 mu L injections) for each of the four...

  2. Liquid chromatographic-mass spectrometric method for ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research ... Purpose: To develop and validate a simple, efficient and reliable Liquid chromatographic-mass spectrometric (LC-MS/MS) method for the quantitative determination of two dermatological drugs, ... By Country · List All Titles · Free To Read Titles This Journal is Open Access.

  3. 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)

  4. Emission spectrometric isotope analyzer

    International Nuclear Information System (INIS)

    Mauersberger, K.; Meier, G.; Nitschke, W.; Rose, W.; Schmidt, G.; Rahm, N.; Andrae, G.; Krieg, D.; Kuefner, W.; Tamme, G.; Wichlacz, D.

    1982-01-01

    An emission spectrometric isotope analyzer has been designed for determining relative abundances of stable isotopes in gaseous samples in discharge tubes, in liquid samples, and in flowing gaseous samples. It consists of a high-frequency generator, a device for defined positioning of discharge tubes, a grating monochromator with oscillating slit and signal converter, signal generator, window discriminator, AND connection, read-out display, oscillograph, gas dosing device and chemical conversion system with carrier gas source and vacuum pump

  5. Car-borne multichannel gamma-ray spectrometric system model CZD-6

    International Nuclear Information System (INIS)

    Lu Shili; Zhai Yugui; Ma Yanfang; Jiao Cangwen; Zhang Biao

    1998-01-01

    The car-borne multichannel gamma-ray spectrometric system Mode CZD-6 is composed of a HDY-256 of portable multichannel gamma-ray spectrometer developed by the Beijing Research Institute of Uranium Geology and a large volume scintillation detector. the position for each measurement point is determined by the GPS instrument. Its latitude and longitude, as well as measured 256 channels of γ-spectrometric data are collected by a notebook computer, which can show the 256 channels of spectra for each point during measuring processes. The complete system can be loaded in a field car. This system has been used to environmental radioactive monitoring after calibration by airborne radiometric models in Shijiazhuang, Hebei province. A lot of data confirm that the system works stably and reliably, and is a fast and advanced approach for environmental γ-spectrometric monitoring. It can be used not only to determination of contents of natural radioactive elements in environments, but also to monitoring nuclear pollution and emergency treatment in nuclear accidents significantly

  6. Membrane filtration of nickel(II) on cellulose acetate filters for its preconcentration, separation, and flame atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Soylak, Mustafa [Chemistry Dept., Faculty of Science Arts, University of Erciyes, Kayseri (Turkey); Unsal, Yunus Emre; Aydin, Ayse [Fen Bilimleri Enstitusu, University of Erciyes, Kayseri (Turkey); Kizil, Nebiye [Saglik Bilimleri Enstitusu, University of Erciyes, Kayseri (Turkey)

    2010-01-15

    An enrichment method for trace amounts of Ni(II), as 8-hydroxyquinoline chelates, has been established on a cellulose acetate membrane filter. Ni(II)-8-hydroxyquinoline chelates adsorbed on a membrane filter were eluted using 5 mL of 1 M HNO{sub 3}. The eluent nickel concentration was determined by a flame atomic absorption spectrometer. The influence of some analytical parameters, including pH, amount of reagent, sample volume, etc., on recovery was investigated. The interference of co-existent ions was studied. The nickel detection limit was 4.87 {mu}g/L. The method was applied to real samples for the determination of nickel(II) ions. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  7. Energy dispersive X-Ray fluorescence spectrometric study of ...

    African Journals Online (AJOL)

    Energy dispersive X-Ray fluorescence spectrometric study of compositional differences in trace elements in dried Moringa oleifera leaves grown in two different agro-ecological locations in Ebonyi State, Nigeria.

  8. Electrothermal atomic absorption spectrometric determination of copper in nickel-base alloys with various chemical modifiers*1

    Science.gov (United States)

    Tsai, Suh-Jen Jane; Shiue, Chia-Chann; Chang, Shiow-Ing

    1997-07-01

    The analytical characteristics of copper in nickel-base alloys have been investigated with electrothermal atomic absorption spectrometry. Deuterium background correction was employed. The effects of various chemical modifiers on the analysis of copper were investigated. Organic modifiers which included 2-(5-bromo-2-pyridylazo)-5-(diethylamino-phenol) (Br-PADAP), ammonium citrate, 1-(2-pyridylazo)-naphthol, 4-(2-pyridylazo)resorcinol, ethylenediaminetetraacetic acid and Triton X-100 were studied. Inorganic modifiers palladium nitrate, magnesium nitrate, aluminum chloride, ammonium dihydrogen phosphate, hydrogen peroxide and potassium nitrate were also applied in this work. In addition, zirconium hydroxide and ammonium hydroxide precipitation methods have also been studied. Interference effects were effectively reduced with Br-PADAP modifier. Aqueous standards were used to construct the calibration curves. The detection limit was 1.9 pg. Standard reference materials of nickel-base alloys were used to evaluate the accuracy of the proposed method. The copper contents determined with the proposed method agreed closely with the certified values of the reference materials. The recoveries were within the range 90-100% with relative standard deviation of less than 10%. Good precision was obtained.

  9. Methylmercury determination using a hyphenated high performance liquid chromatography ultraviolet cold vapor multipath atomic absorption spectrometry system

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Reinaldo C. [Department of Chemistry, Pontifical Catholic University of Rio de Janeiro, Rua Marques de S Vicente 225, 22453-900 Rio de Janeiro (Brazil)], E-mail: rccampos@puc-rio.br; Goncalves, Rodrigo A.; Brandao, Geisamanda P.; Azevedo, Marlo S. [Department of Chemistry, Pontifical Catholic University of Rio de Janeiro, Rua Marques de S Vicente 225, 22453-900 Rio de Janeiro (Brazil); Oliveira, Fabiana; Wasserman, Julio [Institut of Geosciences, Fluminense Federal University, Av. Gal. Milton Tavares de Souza, s/n, 24.210-340, Niteroi, Rio de Janeiro (Brazil)

    2009-06-15

    The present work investigates the use of a multipath cell atomic absorption mercury detector for mercury speciation analysis in a hyphenated high performance liquid chromatography assembly. The multipath absorption cell multiplies the optical path while energy losses are compensated by a very intense primary source. Zeeman-effect background correction compensates for non-specific absorption. For the separation step, the mobile phase consisted in a 0.010% m/v mercaptoethanol solution in 5% methanol (pH = 5), a C{sub 18} column was used as stationary phase, and post column treatment was performed by UV irradiation (60 deg. C, 13 W). The eluate was then merged with 3 mol L{sup -1} HCl, reduction was performed by a NaBH{sub 4} solution, and the Hg vapor formed was separated at the gas-liquid separator and carried through a desiccant membrane to the detector. The detector was easily attached to the system, since an external gas flow to the gas-liquid separator was provided. A multivariate approach was used to optimize the procedure and peak area was used for measurement. Instrumental limits of detection of 0.05 {mu}g L{sup -1} were obtained for ionic (Hg{sup 2+}) and HgCH{sub 3}{sup +}, for an injection volume of 200 {mu}L. The multipath atomic absorption spectrometer proved to be a competitive mercury detector in hyphenated systems in relation to the most commonly used atomic fluorescence and inductively coupled plasma mass spectrometric detectors. Preliminary application studies were performed for the determination of methyl mercury in sedi0011men.

  10. Methylmercury determination using a hyphenated high performance liquid chromatography ultraviolet cold vapor multipath atomic absorption spectrometry system

    International Nuclear Information System (INIS)

    Campos, Reinaldo C.; Goncalves, Rodrigo A.; Brandao, Geisamanda P.; Azevedo, Marlo S.; Oliveira, Fabiana; Wasserman, Julio

    2009-01-01

    The present work investigates the use of a multipath cell atomic absorption mercury detector for mercury speciation analysis in a hyphenated high performance liquid chromatography assembly. The multipath absorption cell multiplies the optical path while energy losses are compensated by a very intense primary source. Zeeman-effect background correction compensates for non-specific absorption. For the separation step, the mobile phase consisted in a 0.010% m/v mercaptoethanol solution in 5% methanol (pH = 5), a C 18 column was used as stationary phase, and post column treatment was performed by UV irradiation (60 deg. C, 13 W). The eluate was then merged with 3 mol L -1 HCl, reduction was performed by a NaBH 4 solution, and the Hg vapor formed was separated at the gas-liquid separator and carried through a desiccant membrane to the detector. The detector was easily attached to the system, since an external gas flow to the gas-liquid separator was provided. A multivariate approach was used to optimize the procedure and peak area was used for measurement. Instrumental limits of detection of 0.05 μg L -1 were obtained for ionic (Hg 2+ ) and HgCH 3 + , for an injection volume of 200 μL. The multipath atomic absorption spectrometer proved to be a competitive mercury detector in hyphenated systems in relation to the most commonly used atomic fluorescence and inductively coupled plasma mass spectrometric detectors. Preliminary application studies were performed for the determination of methyl mercury in sediments.

  11. Elimination of ionic interference effects in the atomic absorption spectrometric determination of ruthenium

    International Nuclear Information System (INIS)

    El-Defrawy, M.M.M.; Posta, J.; Beck, M.T.

    1978-01-01

    In connection with work on the catalytic effect of ruthenium complexes, new compounds were prepared. Atomic absorption spectrometry (a.a.s.) was to be used for their analysis. The standard methods could not be applied to the complexes studied, therefore the effect of cyanide ions for elimination of interfering effects has been studied, because of the great stability of cyanide complexes. (Auth.)

  12. Electrothermal atomic absorption spectrometric determination of cobalt, copper, lead and nickel traces in aragonite following flotation and extraction separation.

    Science.gov (United States)

    Zendelovska, D; Pavlovska, G; Cundeva, K; Stafilov, T

    2001-03-30

    A method of determination of Co, Cu, Pb and Ni in nanogram quantities from aragonite is presented. Flotation and extraction of Co, Cu, Pb and Ni is suggested as methods for elimination matrix interferences of calcium. The method of flotation is performed by iron(III) hexamethylenedithiocarbamate, Fe(HMDTC)(3), as a colloid precipitate collector. The liquid-liquid extraction of Co, Cu, Pb and Ni is carried out by sodium diethyldithiocarbamate, NaDDTC, as complexing reagent into methylisobutyl ketone, MIBK. The electrothermal atomic absorption spectrometry (ETAAS) is used for determination of analytes. The detection limits of ETAAS followed by flotation are: 7.8 ng.g(-1) for Co, 17.1 ng.g(-1) for Cu, 7.2 ng.g(-1) for Pb and 9.0 mug.g(-1) for Ni. The detection limits of ETAAS followed by extraction are found to be: 12.0 ng.g(-1) for Co, 51.0 ng.g(-1) for Cu, 24.0 ng.g(-1) for Pb and 21.0 ng.g(-1) for Ni.

  13. In situ probing of cholesterol in astrocytes at the single-cell level using laser desorption ionization mass spectrometric imaging with colloidal silver.

    Science.gov (United States)

    Perdian, D C; Cha, Sangwon; Oh, Jisun; Sakaguchi, Donald S; Yeung, Edward S; Lee, Young Jin

    2010-04-30

    Mass spectrometric imaging has been utilized to localize individual astrocytes and to obtain cholesterol populations at the single-cell level in laser desorption ionization (LDI) with colloidal silver. The silver ion adduct of membrane-bound cholesterol was monitored to detect individual cells. Good correlation between mass spectrometric and optical images at different cell densities indicates the ability to perform single-cell studies of cholesterol abundance. The feasibility of quantification is confirmed by the agreement between the LDI-MS ion signals and the results from a traditional enzymatic fluorometric assay. We propose that this approach could be an effective tool to study chemical populations at the cellular level. Published in 2010 by John Wiley & Sons, Ltd.

  14. Separation and enrichment of gold(III) from environmental samples prior to its flame atomic absorption spectrometric determination

    International Nuclear Information System (INIS)

    Senturk, Hasan Basri; Gundogdu, Ali; Bulut, Volkan Numan; Duran, Celal; Soylak, Mustafa; Elci, Latif; Tufekci, Mehmet

    2007-01-01

    A simple and accurate method was developed for separation and enrichment of trace levels of gold in environmental samples. The method is based on the adsorption of Au(III)-diethyldithiocarbamate complex on Amberlite XAD-2000 resin prior to the analysis of gold by flame atomic absorption spectrometry after elution with 1 mol L -1 HNO 3 in acetone. Some parameters including nitric acid concentration, eluent type, matrix ions, sample volume, sample flow rate and adsorption capacity were investigated on the recovery of gold(III). The recovery values for gold(III) and detection limit of gold were greater than 95% and 16.6 μg L -1 , respectively. The preconcentration factor was 200. The relative standard deviation of the method was -1 . The validation of the presented procedure was checked by the analysis of CRM-SA-C Sandy Soil certified reference material. The presented procedure was applied to the determination of gold in some environmental samples

  15. Commercial Applications of X Ray Spectrometric Techniques

    International Nuclear Information System (INIS)

    Wegrzynek, D.

    2013-01-01

    In the 21st century, the X-ray fluorescence (XRF) technique is widely used in process control, industrial applications and for routine elemental analysis. The technique has a multielement capability capable of detecting elements with Z ≥ 10, with a few instruments capable of detecting also elements with Z ≥ 5. It is characterized by a non-destructive analysis process and relatively good detection limits, typically one part per million, for a wide range of elements. The first commercial XRF instruments were introduced to the market about 50 years ago. They were the wavelength dispersive X ray fluorescence (WDXRF) spectrometers utilizing Bragg’s law and reflection on crystal lattices for sequential elemental analysis of sample composition. The advances made in radiation detector technology, especially the introduction of semiconductor detectors, improvements in signal processing electronics, availability and exponential growth of personal computer market led to invention of energy dispersive X ray fluorescence (EDXRF) technique. The EDXRF is more cost effective as compared to WDXRF. It also allows for designing compact instruments. Such instruments can be easily tailored to the needs of different customers, integrated with industrial installations, and also miniaturized for the purpose of in-situ applications. The versatility of the technique has been confirmed in a spectacular way by using the XRF and X-ray spectrometric techniques, among few others, during the NASA and ESA missions in search for the evidence of life and presence of water on the surface of Mars. The XRF technique has achieved its strong position within the atomic spectroscopy group of analytical techniques not only due to its versatility but also due to relatively low running costs, as compared to the commonly used methods, e.g., atomic absorption spectrometry (AAS) or inductively coupled plasma atomic emission/mass spectrometry (ICP-AES/MS). Presently, the XRF technique together with X ray

  16. Ultratrace determination of tin by hydride generation in-atomizer trapping atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Průša, Libor [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Charles University in Prague, Faculty of Science, Department of Analytical Chemistry, Hlavova 8, Prague 2, CZ 128 43 Czech Republic (Czech Republic); Dědina, Jiří [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Kratzer, Jan, E-mail: jkratzer@biomed.cas.cz [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic)

    2013-12-04

    Graphical abstract: -- Highlights: •In-atomizer trapping HG-AAS was optimized for Sn. •A compact quartz trap-and-atomizer device was employed. •Generation, preconcentration and atomization steps were investigated in detail. •Hundred percent preconcentration efficiency for tin was reached. •Routine analytical method was developed for Sn determination (LOD of 0.03 ng mL{sup −1} Sn). -- Abstract: A quartz multiatomizer with its inlet arm modified to serve as a trap (trap-and-atomizer device) was employed to trap tin hydride and subsequently to volatilize collected analyte species with atomic absorption spectrometric detection. Generation, atomization and preconcentration conditions were optimized and analytical figures of merit of both on-line atomization as well as preconcentration modes were quantified. Preconcentration efficiency of 95 ± 5% was found. The detection limits reached were 0.029 and 0.14 ng mL{sup −1} Sn, respectively, for 120 s preconcentration period and on-line atomization mode without any preconcentration. The interference extent of other hydride forming elements (As, Se, Sb and Bi) on tin determination was found negligible in both modes of operation. The applicability of the developed preconcentration method was verified by Sn determination in a certified reference material as well as by analysis of real samples.

  17. Mass spectrometric researches in isotope cosmochemistry

    International Nuclear Information System (INIS)

    Gopalan, K.

    1979-01-01

    Recent advances in the understanding of solar system processes, past and present, based on mass spectrometric researches on meteorites and moon samples are reviewed. The topics include the following : (1) Duration of nebular condensation, (2) Terminal stages of nucleosynthesis, (3) Planetary formation and evolution, (4) Heterogeneities in the solar nebula and (5) Solar wind composition. (auth.)

  18. In situ monitoring of molecular changes during cell differentiation processes in marine macroalgae through mass spectrometric imaging.

    Science.gov (United States)

    Kessler, Ralf W; Crecelius, Anna C; Schubert, Ulrich S; Wichard, Thomas

    2017-08-01

    Matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI) was employed to discriminate between cell differentiation processes in macroalgae. One of the key developmental processes in the algal life cycle is the production of germ cells (gametes and zoids). The gametogenesis of the marine green macroalga Ulva mutabilis (Chlorophyta) was monitored by metabolomic snapshots of the surface, when blade cells differentiate synchronously into gametangia and giving rise to gametes. To establish MSI for macroalgae, dimethylsulfoniopropionate (DMSP), a known algal osmolyte, was determined. MSI of the surface of U. mutabilis followed by chemometric data analysis revealed dynamic metabolomic changes during cell differentiation. DMSP and a total of 55 specific molecular biomarkers, which could be assigned to important stages of the gametogenesis, were detected. Our research contributes to the understanding of molecular mechanisms underlying macroalgal cell differentiation. Graphical abstract Molecular changes during cell differentiation of the marine macroalga Ulva were visualized by matrix assisted laser desorption/ionization mass spectrometric imaging (MALDI-MSI).

  19. Determination of trace elements in paints by direct sampling graphite furnace atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Bentlin, Fabrina R.S.; Pozebon, Dirce; Mello, Paola A.; Flores, Erico M.M.

    2007-01-01

    A direct sampling graphite furnace atomic absorption spectrometric (DS-GFAAS) method for the determination of Cd, Pb, Cr, Ni, Co and Cu in paints has been developed. Serigraphy, acrylic and tattoo paints were analysed. Approaches like pyrolysis and atomization temperatures, modifiers and sample mass introduced in the atomizer were studied. Quantification was performed using calibration curves measured with aqueous standard solutions pipetted onto the platform. The sample mass introduced in the graphite tube ranged from 0.02 to 8.0 mg. Palladium was used as modifier for Cd, Pb and Cu, while Mg(NO 3 ) 2 was used for Co. For Ni determination, the graphite platform was covered with carbon powder. The characteristic masses of Cd, Pb, Cr, Ni, Co and Cu were 1.4, 22.5, 7.9, 11.0, 9.6 and 12.5 pg, while the limits of detection were 0.0004, 0.001, 0.03, 0.22, 0.11 and 0.05 μg g -1 of Cd, Pb, Cr, Ni, Co and Cu, respectively. The accuracy was determined by comparison of the results with those obtained by inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (GFAAS), using liquid sampling of digests. For matrix characterization, major and minor elements (Al, Mg, Ba, Ca, Cr, Cu, Pb, Sr, Ti and Mg) were determined by inductively coupled plasma optical emission spectrometry (ICP OES)

  20. Wavelength modulation spectroscopy--digital detection of gas absorption harmonics based on Fourier analysis.

    Science.gov (United States)

    Mei, Liang; Svanberg, Sune

    2015-03-20

    This work presents a detailed study of the theoretical aspects of the Fourier analysis method, which has been utilized for gas absorption harmonic detection in wavelength modulation spectroscopy (WMS). The lock-in detection of the harmonic signal is accomplished by studying the phase term of the inverse Fourier transform of the Fourier spectrum that corresponds to the harmonic signal. The mathematics and the corresponding simulation results are given for each procedure when applying the Fourier analysis method. The present work provides a detailed view of the WMS technique when applying the Fourier analysis method.

  1. Spectrometric properties of crystals for low-energy x-ray diagnostics

    International Nuclear Information System (INIS)

    Barrus, D.m.; Blake, R.L.; Felthauser, H.; Fenimore, E.E.

    1981-01-01

    Quantitative diagnostics of fusion and astrophysical plasmas require knowledge of crystal spectrometric properties. To provide more reliable and versatile diagnostics of plasma conditions, increasingly accurate knowledge of crystal spectrometric properties is becoming necessary. A summary is presented of the following accurately measured parameters for the crystals KAP, RbAP, TlAP, NH 4 AP, NaAP, ADP, and EDDT: the interplanar spacing of atoms; the angle correction for normal and anomalous dispersion that is required for application of the Bragg formula; the thermal expansion coefficient near room temperature for commonly used planes; and the integrated coefficient of reflection

  2. Trace determination of antimony by hydride generation atomic absorption spectrometry with analyte preconcentration/atomization in a dielectric barrier discharge atomizer.

    Science.gov (United States)

    Zurynková, Pavla; Dědina, Jiří; Kratzer, Jan

    2018-06-20

    Atomization conditions for antimony hydride in the plasma atomizer based on a dielectric barrier discharge (DBD) with atomic absorption spectrometric detection were optimized. Argon was found as the best discharge gas under a flow rate of 50 mL min - 1 while the DBD power was optimum at 30 W. Analytical figures of merit including interference study of As, Se and Bi have been subsequently investigated and the results compared to those found in an externally heated quartz tube atomizer (QTA). The limit of detection (LOD) reached in DBD (0.15 ng mL -1  Sb) is comparable to that observed in QTA (0.14 ng mL -1  Sb). Finally, possibility of Sb preconcentration by stibane in situ trapping in a DBD atomizer was studied. For trapping time of 300 s, the preconcentration efficiency and LOD, respectively, were 103 ± 2% and 0.02 ng mL -1 . Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Graphite furnace atomic absorption spectrometric determination of vanadium after cloud point extraction in the presence of graphene oxide

    Science.gov (United States)

    López-García, Ignacio; Marín-Hernández, Juan José; Hernández-Córdoba, Manuel

    2018-05-01

    Vanadium (V) and vanadium (IV) in the presence of a small concentration of graphene oxide (0.05 mg mL-1) are quantitatively transferred to the coacervate obtained with Triton X-114 in a cloud point microextraction process. The surfactant-rich phase is directly injected into the graphite atomizer of an atomic absorption spectrometer. Using a 10-mL aliquot sample and 150 μL of a 15% Triton X-114 solution, the enrichment factor for the analyte is 103, which results in a detection limit of 0.02 μg L-1 vanadium. The separation of V(V) and V(IV) using an ion-exchanger allows speciation of the element at low concentrations. Data for seven reference water samples with certified vanadium contents confirm the reliability of the procedure. Several beer samples are also analyzed, those supplied as canned drinks showing low levels of tetravalent vanadium.

  4. Determination of lithium and potassium in uranium oxide powders and pellets by Flame Atomic Emission Spectrometric method

    International Nuclear Information System (INIS)

    Jat, J.R.; Balaji Rao, Y.; Prasada Rao, G.; Prahlad, B.

    2012-01-01

    The present paper describes a method developed at Control Laboratory, NFC which includes prior separation of lithium and potassium from uranium matrix before their measurements. Solvent extraction, using Tri-n-Butyl Phosphate (TBP) in CCI 4 followed by Tri-n-Octyl Phosphine Oxide (TOPO) in CCI 4 , is employed for prior separation of Li and K. The resultant aqueous solution was analyzed by Flame-Atomic Emission Spectrometric (AES) method. Solvent extraction conditions are optimized for measurement of Li and K in the same aliquot. Experimental conditions such as instrument calibration, flame condition, fuel flow, sample flow rate through nebulizer, burner height etc. are also optimized. Under the optimal condition the detection limits achieved for lithium is 0.02 ppm and 0.2 ppm for potassium. A RSD of ± 3 % for Li at 0.05 ppm and ± 4% for K at 1 ppm level has been achieved in this method. The results of lithium in the sample are compared with the values obtained by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Similarly, values of potassium are compared with Flame-Atomic Absorption Spectrometry (Flame-AAS) technique. The comparisons are in good agreement. The above method is simple, sensitive, reproducible and can be used for measurement of lithium and potassium in UO 2 powder and pellets on regular basis

  5. The theoretical study of full spectrum analysis method for airborne gamma-ray spectrometric data

    International Nuclear Information System (INIS)

    Ni Weichong

    2011-01-01

    Spectra of airborne gamma-ray spectrometry was found to be the synthesis of spectral components of radioelement sources by analyzing the constitution of radioactive sources for airborne gamma-ray spectrometric survey and establishing the models of gamma-ray measurement. The mathematical equation for analysising airborne gamma-ray full spectrometric data can be expressed into matrix and related expansions were developed for the mineral resources exploration, environmental radiation measurement, nuclear emergency monitoring, and so on. Theoretical study showed that the atmospheric radon could be directly computed by airborne gamma-ray spectrometric data with full spectrum analysis without the use of the accessional upward-looking detectors. (authors)

  6. Determination of Triazine Herbicides in Drinking Water by Dispersive Micro Solid Phase Extraction with Ultrahigh-Performance Liquid Chromatography-High-Resolution Mass Spectrometric Detection.

    Science.gov (United States)

    Chen, Dawei; Zhang, Yiping; Miao, Hong; Zhao, Yunfeng; Wu, Yongning

    2015-11-11

    A novel dispersive micro solid phase extraction (DMSPE) method based on a polymer cation exchange material (PCX) was applied to the simultaneous determination of the 30 triazine herbicides in drinking water with ultrahigh-performance liquid chromatography-high-resolution mass spectrometric detection. Drinking water samples were acidified with formic acid, and then triazines were adsorbed by the PCX sorbent. Subsequently, the analytes were eluted with ammonium hydroxide/acetonitrile. The chromatographic separation was performed on an HSS T3 column using water (4 mM ammonium formate and 0.1% formic acid) and acetonitrile (0.1% formic acid) as the mobile phase. The method achieved LODs of 0.2-30.0 ng/L for the 30 triazines, with recoveries in the range of 70.5-112.1%, and the precision of the method was better than 12.7%. These results indicated that the proposed method had the advantages of convenience and high efficiency when applied to the analysis of the 30 triazines in drinking water.

  7. Application of cloud point preconcentration and flame atomic absorption spectrometry for the determination of cadmium and zinc ions in urine, blood serum and water samples

    Directory of Open Access Journals (Sweden)

    Ardeshir Shokrollahi

    2013-01-01

    Full Text Available A simple, sensitive and selective cloud point extraction procedure is described for the preconcentration and atomic absorption spectrometric determination of Zn2+ and Cd2+ ions in water and biological samples, after complexation with 3,3',3",3'"-tetraindolyl (terephthaloyl dimethane (TTDM in basic medium, using Triton X-114 as nonionic surfactant. Detection limits of 3.0 and 2.0 µg L-1 and quantification limits 10.0 and 7.0 µg L-1were obtained for Zn2+ and Cd2+ ions, respectively. Relative standard deviation was 2.9 and 3.3, and enrichment factors 23.9 and 25.6, for Zn2+ and Cd2+ ions, respectively. The method enabled determination of low levels of Zn2+ and Cd2+ ions in urine, blood serum and water samples.

  8. Separation and enrichment of gold(III) from environmental samples prior to its flame atomic absorption spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Senturk, Hasan Basri; Gundogdu, Ali [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Bulut, Volkan Numan [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 28049 Giresun (Turkey); Duran, Celal [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Arts and Sciences, Erciyes University, 38039 Kayseri (Turkey)], E-mail: soylak@erciyes.edu.tr; Elci, Latif [Department of Chemistry, Faculty of Arts and Sciences, Pamukkale University, 20020 Denizli (Turkey); Tufekci, Mehmet [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2007-10-22

    A simple and accurate method was developed for separation and enrichment of trace levels of gold in environmental samples. The method is based on the adsorption of Au(III)-diethyldithiocarbamate complex on Amberlite XAD-2000 resin prior to the analysis of gold by flame atomic absorption spectrometry after elution with 1 mol L{sup -1} HNO{sub 3} in acetone. Some parameters including nitric acid concentration, eluent type, matrix ions, sample volume, sample flow rate and adsorption capacity were investigated on the recovery of gold(III). The recovery values for gold(III) and detection limit of gold were greater than 95% and 16.6 {mu}g L{sup -1}, respectively. The preconcentration factor was 200. The relative standard deviation of the method was <6%. The adsorption capacity of the resin was 12.3 mg g{sup -1}. The validation of the presented procedure was checked by the analysis of CRM-SA-C Sandy Soil certified reference material. The presented procedure was applied to the determination of gold in some environmental samples.

  9. Standard test methods for chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide (Gd2O3) powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 These test methods cover procedures for the chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide powders to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Carbon by Direct CombustionThermal Conductivity C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Total Chlorine and Fluorine by Pyrohydrolysis Ion Selective Electrode C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Loss of Weight on Ignition 7-13 Sulfur by CombustionIodometric Titration Impurity Elements by a Spark-Source Mass Spectrographic C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical,Nuclear, and Radiochemical Analysis of Uranium Hexafluoride C1287 Test Method for Determination of Impurities In Uranium Dioxide By Inductively Coupled Plasma Mass Spectrometry Gadolinium Content in Gadolinium Oxid...

  10. Identification of Polish cochineal (Porphyrophora polonica L.) in historical textiles by high-performance liquid chromatography coupled with spectrophotometric and tandem mass spectrometric detection.

    Science.gov (United States)

    Lech, Katarzyna; Jarosz, Maciej

    2016-05-01

    The present work reports a method for identification of Polish cochineal (Porphyrophora polonica L.) in historical fabrics by the use of high-performance liquid chromatography coupled with diode array and tandem mass spectrometric detection with electrospray ionization (HPLC-DAD-ESI MS/MS). This hyphened technique allows detection and identification of 16 new minor colorants present in the discussed scale insect (including two previously observed by Wouters and Verhecken (Ann Soc Entomol Fr. 1989;25:393-410), but specified only as compounds of unknown structures) that do not occur (e.g., in American cochineal). The MS/MS experiments, complemented with UV-VIS data, enable identification of mono- and di-, C- and O-hexosides of kermesic and flavokermesic acids or their derivatives. The present paper introduces a fingerprint of color compounds present in Polish cochineal and defines them, particularly pp6 (ppI, O-hexoside of flavokermesic acid), as its markers allow distinguishing of Polish-cochineal reds from the American ones. Usefulness of the selected set of markers for identification of Polish cochineal has been demonstrated in the examination of textiles from the collection of the National Museum in Warsaw using the multiple reaction monitoring (MRM) method, originally elaborated on the basis of this study.

  11. Tunable Diode Laser Atomic Absorption Spectroscopy for Detection of Potassium under Optically Thick Conditions.

    Science.gov (United States)

    Qu, Zhechao; Steinvall, Erik; Ghorbani, Ramin; Schmidt, Florian M

    2016-04-05

    Potassium (K) is an important element related to ash and fine-particle formation in biomass combustion processes. In situ measurements of gaseous atomic potassium, K(g), using robust optical absorption techniques can provide valuable insight into the K chemistry. However, for typical parts per billion K(g) concentrations in biomass flames and reactor gases, the product of atomic line strength and absorption path length can give rise to such high absorbance that the sample becomes opaque around the transition line center. We present a tunable diode laser atomic absorption spectroscopy (TDLAAS) methodology that enables accurate, calibration-free species quantification even under optically thick conditions, given that Beer-Lambert's law is valid. Analyte concentration and collisional line shape broadening are simultaneously determined by a least-squares fit of simulated to measured absorption profiles. Method validation measurements of K(g) concentrations in saturated potassium hydroxide vapor in the temperature range 950-1200 K showed excellent agreement with equilibrium calculations, and a dynamic range from 40 pptv cm to 40 ppmv cm. The applicability of the compact TDLAAS sensor is demonstrated by real-time detection of K(g) concentrations close to biomass pellets during atmospheric combustion in a laboratory reactor.

  12. Detection of metal stress in boreal forest species using the 0.67-micron chlorophyll absorption band

    Science.gov (United States)

    Singhroy, Vernon H.; Kruse, Fred A.

    1991-01-01

    Several recent studies have shown that a shift of the red-edge inflection near 0.70 micron in vegetation reflectance spectra is an indicator of metal stress, partially attributable to changes in chlorophyll concentration. This 'red-edge shift', however, is difficult to detect and has been reported both toward longer (red) and shorter (blue) wavelengths. Our work demonstrates that direct measurement of the depth and width of the chlorophyll absorption band at 0.67 micron using digital feature extraction and absorption band characterization procedures developed for the analysis of mineral spectra is a more consistent indicator of metal stress. Additionally, the magnitude of these parameters is generally greater than that of the red edge shift and thus should be more amenable to detection and mapping using field and aircraft spectrometers.

  13. Ion chromatography with the indirect ultraviolet detection of alkali metal ions and ammonium using imidazolium ionic liquid as ultraviolet absorption reagent and eluent.

    Science.gov (United States)

    Liu, Yong-Qiang; Yu, Hong

    2016-08-01

    Indirect ultraviolet detection was conducted in ultraviolet-absorption-agent-added mobile phase to complete the detection of the absence of ultraviolet absorption functional group in analytes. Compared with precolumn derivatization or postcolumn derivatization, this method can be widely used, has the advantages of simple operation and good linear relationship. Chromatographic separation of Li(+) , Na(+) , K(+) , and NH4 (+) was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid/organic solvent as the mobile phase, in which imidazolium ionic liquids acted as ultraviolet absorption reagent and eluting agent. The retention behaviors of four kinds of cations are discussed, and the mechanism of separation and detection are described. The main factors influencing the separation and detection were the background ultraviolet absorption reagent and the concentration of hydrogen ion in the ion chromatography-indirect ultraviolet detection. The successful separation and detection of Li(+) , Na(+) , K(+) , and NH4 (+) within 13 min was achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.02, 0.11, 0.30, and 0.06 mg/L, respectively. A new separation and analysis method of alkali metal ions and ammonium by ion chromatography with indirect ultraviolet detection method was developed, and the application range of ionic liquid was expanded. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Structure elucidation of metabolite x17299 by interpretation of mass spectrometric data.

    Science.gov (United States)

    Zhang, Qibo; Ford, Lisa A; Evans, Anne M; Toal, Douglas R

    2017-01-01

    A major bottleneck in metabolomic studies is metabolite identification from accurate mass spectrometric data. Metabolite x17299 was identified in plasma as an unknown in a metabolomic study using a compound-centric approach where the associated ion features of the compound were used to determine the true molecular mass. The aim of this work is to elucidate the chemical structure of x17299, a new compound by de novo interpretation of mass spectrometric data. An Orbitrap Elite mass spectrometer was used for acquisition of mass spectra up to MS 4 at high resolution. Synthetic standards of N,N,N -trimethyl-l-alanyl-l-proline betaine (l,l-TMAP), a diastereomer, and an enantiomer were chemically prepared. The planar structure of x17299 was successfully proposed by de novo mechanistic interpretation of mass spectrometric data without any laborious purification and nuclear magnetic resonance spectroscopic analysis. The proposed structure was verified by deuterium exchanged mass spectrometric analysis and confirmed by comparison to a synthetic standard. Relative configuration of x17299 was determined by direct chromatographic comparison to a pair of synthetic diastereomers. Absolute configuration was assigned after derivatization of x17299 with a chiral auxiliary group followed by its chromatographic comparison to a pair of synthetic standards. The chemical structure of metabolite x17299 was determined to be l,l-TMAP.

  15. Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection

    International Nuclear Information System (INIS)

    Steffen, S.; Otto, M.; Niewoehner, L.; Barth, M.; Brozek-Mucha, Z.; Biegstraaten, J.; Horvath, R.

    2007-01-01

    A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: 'gunshot residue characteristic', 'consistent with gunshot residue' and environmental particles, respectively. Potential gunshot residue particles are manually checked and - if necessary - confirmed by the operating forensic scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification

  16. Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, S. [Bundeskriminalamt (BKA), Forensic Science Institute KT23, Thaerstr. 11, D - 65193 Wiesbaden (Germany); Otto, M. [TU Bergakademie Freiberg (TU BAF), Institute for Analytical Chemistry, Leipziger Str. 29, D - 09599 Freiberg (Germany)], E-mail: matthias.otto@chemie.tu-freiberg.de; Niewoehner, L.; Barth, M. [Bundeskriminalamt (BKA), Forensic Science Institute KT23, Thaerstr. 11, D - 65193 Wiesbaden (Germany); Brozek-Mucha, Z. [Instytut Ekspertyz Sadowych (IES), Westerplatte St. 9, PL - 31-033 Krakow (Poland); Biegstraaten, J. [Nederlands Forensisch Instituut (NFI), Fysische Technologie, Laan van Ypenburg 6, NL-2497 GB Den Haag (Netherlands); Horvath, R. [Kriminalisticky a Expertizny Ustav (KEU PZ), Institute of Forensic Science, Sklabinska 1, SK - 812 72 Bratislava (Slovakia)

    2007-09-15

    A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: 'gunshot residue characteristic', 'consistent with gunshot residue' and environmental particles, respectively. Potential gunshot residue particles are manually checked and - if necessary - confirmed by the operating forensic scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification.

  17. Electronic equipment for spectrometric data processing

    International Nuclear Information System (INIS)

    Antonov, L.J.; Trenev, A.M.; Todorova, E.I.; Dimitrov, V.D.

    1978-01-01

    Electronic equipment carrying out logical operations and a full set of the arithmetic operations was developed for spectrometric data processing. The flowsheet of the computing part of the device, made on the basis of a specialized integral circuit, is given. The device includes input registers, multiplexor, matrix commutator, arithmetic unit and indication unit. The equipment is rated to carry out calculations according to comparatively complex formulae in several seconds

  18. Uncertainty assessment in gamma spectrometric measurements of plutonium isotope ratios and age

    Energy Technology Data Exchange (ETDEWEB)

    Ramebaeck, H., E-mail: henrik.ramebeck@foi.se [Swedish Defence Research Agency, FOI, Division of CBRN Defence and Security, SE-901 82 Umea (Sweden); Chalmers University of Technology, Department of Chemical and Biological Engineering, Nuclear Chemistry, SE-412 96 Goeteborg (Sweden); Nygren, U.; Tovedal, A. [Swedish Defence Research Agency, FOI, Division of CBRN Defence and Security, SE-901 82 Umea (Sweden); Ekberg, C.; Skarnemark, G. [Chalmers University of Technology, Department of Chemical and Biological Engineering, Nuclear Chemistry, SE-412 96 Goeteborg (Sweden)

    2012-09-15

    A method for the assessment of the combined uncertainty in gamma spectrometric measurements of plutonium composition and age was evaluated. Two materials were measured. Isotope dilution inductively coupled plasma sector field mass spectrometry (ID-ICP-SFMS) was used as a reference method for comparing the results obtained with the gamma spectrometric method for one of the materials. For this material (weapons grade plutonium) the measurement results were in agreement between the two methods for all measurands. Moreover, the combined uncertainty in all isotope ratios considered in this material (R{sub Pu238/Pu239}, R{sub Pu240/Pu239}, R{sub Pu241/Pu239}, and R{sub Am241/Pu241} for age determination) were limited by counting statistics. However, the combined uncertainty for the other material (fuel grade plutonium) were limited by the response fit, which shows that the uncertainty in the response function is important to include in the combined measurement uncertainty of gamma spectrometric measurements of plutonium.

  19. Validation of a method to the addition the multiple standard in the analysis of Pb in reservoir waters for atomic absorption spectrometric

    International Nuclear Information System (INIS)

    Mayari, R.; Espinosa, M.C.; Vazques, J.

    2003-01-01

    The evaluation of a method is presented for the analysis of Pb in reservoir waters for atomic spectrometric with direct aspiration. For the validation of the analytic method a level of concentration of 0.05 mg/L was evaluated. The precision of the method was of 9.97% and the bias was 0.6% 8 samples of surface waters they were collected and of bottom of the tributaries of the reservoir Scorpions and the stocking of the concentrations in the tributaries was from 0,052 + - 0.026 inferior mg/L to the established one in the Cuban norm of evaluation of the hydirc objects of fishing use

  20. A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry.

    Science.gov (United States)

    Tuzen, Mustafa; Soylak, Mustafa; Citak, Demirhan; Ferreira, Hadla S; Korn, Maria G A; Bezerra, Marcos A

    2009-03-15

    A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L(-1) nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 microg L(-1), respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 microg L(-1). The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish.

  1. A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Tuzen, Mustafa; Soylak, Mustafa; Citak, Demirhan; Ferreira, Hadla S.; Korn, Maria G.A.; Bezerra, Marcos A.

    2009-01-01

    A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L -1 nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 μg L -1 , respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 μg L -1 . The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish

  2. Near-infrared incoherent broadband cavity enhanced absorption spectroscopy (NIR-IBBCEAS) for detection and quantification of natural gas components.

    Science.gov (United States)

    Prakash, Neeraj; Ramachandran, Arun; Varma, Ravi; Chen, Jun; Mazzoleni, Claudio; Du, Ke

    2018-06-28

    The principle of near-infrared incoherent broadband cavity enhanced absorption spectroscopy was employed to develop a novel instrument for detecting natural gas leaks as well as for testing the quality of natural gas mixtures. The instrument utilizes the absorption features of methane, butane, ethane, and propane in the wavelength region of 1100 nm to 1250 nm. The absorption cross-section spectrum in this region for methane was adopted from the HITRAN database, and those for the other three gases were measured in the laboratory. A singular-value decomposition (SVD) based analysis scheme was employed for quantifying methane, butane, ethane, and propane by performing a linear least-square fit. The developed instrument achieved a detection limit of 460 ppm, 141 ppm, 175 ppm and 173 ppm for methane, butane, ethane, and propane, respectively, with a measurement time of 1 second and a cavity length of 0.59 m. These detection limits are less than 1% of the Lower Explosive Limit (LEL) for each gas. The sensitivity can be further enhanced by changing the experimental parameters (such as cavity length, lamp power etc.) and using longer averaging intervals. The detection system is a low-cost and portable instrument suitable for performing field monitorings. The results obtained on the gas mixture emphasize the instrument's potential for deployment at industrial facilities dealing with natural gas, where potential leaks pose a threat to public safety.

  3. Diffuse-light absorption spectroscopy by fiber optics for detecting and quantifying the adulteration of extra virgin olive oil

    Science.gov (United States)

    Mignani, A. G.; Ciaccheri, L.; Ottevaere, H.; Thienpont, H.; Conte, L.; Marega, M.; Cichelli, A.; Attilio, C.; Cimato, A.

    2010-09-01

    A fiber optic setup for diffuse-light absorption spectroscopy in the wide 400-1700 nm spectral range is experimented for detecting and quantifying the adulteration of extra virgin olive oil caused by lower-grade olive oils. Absorption measurements provide spectral fingerprints of authentic and adulterated oils. A multivariate processing of spectroscopic data is applied for discriminating the type of adulterant and for predicting its fraction.

  4. A gas/liquid chromatographic-mass spectrometric method for the rapid screening of 250 pesticides in aqueous matrices

    Energy Technology Data Exchange (ETDEWEB)

    Chandramouli, B.; Harvan, D.; Brittain, S.; Hass, R. [Eno River Labs, LLC. Durham, NC (United States)

    2004-09-15

    Pesticide residues in food present a potentially serious and significant cause for concern. Many pesticides have been associated with significant health effects to the nervous and endocrine systems and some have been deemed carcinogenic. There are many well-established techniques for pesticide analysis. However, commercial pesticide methods have traditionally only been available for specific pesticide families, such as chlorinated pesticides or herbicides, and at detection limits ranging from 0.05 ppb to 1 ppm in aqueous matrices. Techniques that can quickly screen for the presence/absence of pesticide residues in food matrices are critical in ensuring the safety of food and water. This paper outlines a combined Gas Chromatographic-High Resolution Mass Spectrometric (GC-HRMS) and Liquid Chromatographic Tandem Mass Spectrometric (LC-MS/MS) screening assay for 250 pesticides that was developed for use in water, and soda samples at screening levels ranging from 0.1-5 ppb. The pesticides selected have been identified by the European Union as being of concern and the target of possible legislation. The list encompasses a variety of pesticide classes and compound groupings.

  5. Wet bar detection by using water absorption detector

    International Nuclear Information System (INIS)

    Kim, Hee Soo; Bae, Yong Chae; Kee, Chang Doo

    2008-01-01

    Water leaks in water-cooled generator stator windings can generate serious accidents such as insulation breakdown and result in unexpected sudden outages. Thus, it is important to diagnose their water absorption for effective operation of the power plant. Especially, since the capacitance values that are measured for diagnosis are very small so special diagnosis methods like stochastic theory are needed. KEPRI developed a more advanced water absorption detector and diagnosis technology for it. They were applied to a real system and the results of the water absorption test for stator windings agree with the water leak test

  6. MASERATI: a new rocket-borne diode laser absorption spectrometer for in-situ measurement of trace gases in the middle and upper atmosphere; MASERATI: Ein neues raketengetragenes Diodenlaser-Absorptionsspektrometer zur in situ-Messung von Spurengasen in der mittleren und oberen Atmosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Lucke, H. von

    1999-09-01

    MASERATI (middle atmosphere spectrometric experiment on Rockets for the analysis of trace gas influences) is the first rocket-borne tunable diode laser absorption spectrometer (TDLAS). It was developed to measure water vapor and carbon dioxide in the altitude range from 50 to 90 km and 120 km, respectively. Infrared absorption spectroscopy using two laser diodes is applied to measure both trace gases simultaneously. The laser beams are sent into an open multiple-pass absorption setup mounted on top of the sounding rocket. High sensitivity is achieved by means of frequency modulation and lock-in techniques. The results of several tests performed in the laboratory demonstrate that the instrument is capable of detecting relative absorbances down to 10{sup -4} - 10{sup -5} when integrating spectra for 1 s. Two almost identical MASERATI instruments have been built and launched on sounding rockets from the Andoeya rocket range (69 N, 16 E) in northern Norway during winter 1997/98. The results of these flights demonstrate that MASERATI is a new suitable tool for in situ studies of the mesosphere and lower thermosphere. (orig.)

  7. Spectrometric and Voltammetric Analysis of Urease – Nickel Nanoelectrode as an Electrochemical Sensor

    Directory of Open Access Journals (Sweden)

    Rene Kizek

    2007-07-01

    Full Text Available Urease is the enzyme catalyzing the hydrolysis of urea into carbon dioxide andammonia. This enzyme is substrate-specific, which means that the enzyme catalyzes thehydrolysis of urea only. This feature is a basic diagnostic criterion used in thedetermination of many bacteria species. Most of the methods utilized for detection ofurease are based on analysis of its enzyme activity – the hydrolysis of urea. The aim of thiswork was to detect urease indirectly by spectrometric method and directly by voltammetricmethods. As spectrometric method we used is called indophenol assay. The sensitivity ofdetection itself is not sufficient to analyse the samples without pre-concentration steps.Therefore we utilized adsorptive transfer stripping technique coupled with differential pulse voltammetry to detect urease. The influence of accumulation time, pH of supporting electrolyte and concentration of urease on the enzyme peak height was investigated. Under the optimized experimental conditions (0.2 M acetate buffer pH 4.6 and accumulation time of 120 s the detection limit of urease evaluated as 3 S/N was 200 ng/ml. The activity of urease enzyme depends on the presence of nickel. Thus the influence of nickel(II ions on electrochemical response of the enzyme was studied. Based on the results obtained the interaction of nickel(II ions and urease can be determined using electrochemical methods. Therefore we prepared Ni nanoelectrodes to measure urease. The Ni nanoelectrodes was analysed after the template dissolution by scanning electron microscopy. The results shown vertically aligned Ni nanopillars almost covered the electrode surface, whereas the defect places are minor and insignificant in comparison with total electrode surface. We were able to not only detect urease itself but also to distinguish its native and denatured form.

  8. Determination of trace elements in paints by direct sampling graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bentlin, Fabrina R.S. [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, UFRGS, 91501-970 Porto Alegre, RS (Brazil); Pozebon, Dirce [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, UFRGS, 91501-970 Porto Alegre, RS (Brazil)], E-mail: dircepoz@iq.ufrgs.br; Mello, Paola A.; Flores, Erico M.M. [Departamento de Quimica, Universidade Federal de Santa Maria, UFSM, 97105-900 Santa Maria, RS (Brazil)

    2007-10-17

    A direct sampling graphite furnace atomic absorption spectrometric (DS-GFAAS) method for the determination of Cd, Pb, Cr, Ni, Co and Cu in paints has been developed. Serigraphy, acrylic and tattoo paints were analysed. Approaches like pyrolysis and atomization temperatures, modifiers and sample mass introduced in the atomizer were studied. Quantification was performed using calibration curves measured with aqueous standard solutions pipetted onto the platform. The sample mass introduced in the graphite tube ranged from 0.02 to 8.0 mg. Palladium was used as modifier for Cd, Pb and Cu, while Mg(NO{sub 3}){sub 2} was used for Co. For Ni determination, the graphite platform was covered with carbon powder. The characteristic masses of Cd, Pb, Cr, Ni, Co and Cu were 1.4, 22.5, 7.9, 11.0, 9.6 and 12.5 pg, while the limits of detection were 0.0004, 0.001, 0.03, 0.22, 0.11 and 0.05 {mu}g g{sup -1} of Cd, Pb, Cr, Ni, Co and Cu, respectively. The accuracy was determined by comparison of the results with those obtained by inductively coupled plasma mass spectrometry (ICP-MS) and graphite furnace atomic absorption spectrometry (GFAAS), using liquid sampling of digests. For matrix characterization, major and minor elements (Al, Mg, Ba, Ca, Cr, Cu, Pb, Sr, Ti and Mg) were determined by inductively coupled plasma optical emission spectrometry (ICP OES)

  9. The application study on the prospecting for gold by car-borne gamma-ray spectrometric method in northern Hebei and other areas

    International Nuclear Information System (INIS)

    Ma Zhongxiang; Liu Tengyao; Zhang Peng; Lu Shili; Zhai Yugui; Ma Yanfang

    1995-01-01

    The prospecting method for gold by car-borne gamma-ray spectrometric survey is a new geophysical and geochemical technique in the search for concealed gold deposits which can be used to effectively predict the regional gold metallogenetic potential area. The method of car-borne gamma-ray spectrometric survey was adopted and 63416 data at gamma-ray spectrometric measuring sites from rock masses (or strata) in northern Hebei and other areas (49100 km 2 ) are obtained. On the basis of the size of geological bodies, the sliding filtering technique was applied to process the gamma-ray spectrometric data from regional geological bodies and maps showing the parameter distribution characteristics were plotted (11 sheets). In accordance with the thorough on the distribution characteristics of gamma-ray spectrometric parameters that reflect the regional geological environment of gold metallogenesis, a set of gamma-ray spectrometric combination parameters in correlation with regional gold metallogenesis has been established and the characteristic information of gamma-ray spectrometric parameters has been extracted. Combined with geological information, the gold metallogenetic geological environment in the working area was studied, and two potential areas were predicted. After verification, gold mineralization was encountered in some areas. The study results show that the car-borne gamma-ray spectrometric method used for regional gold prospecting is a rapid, economical and effective one

  10. A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry

    OpenAIRE

    Tuzen, Mustafa; Soylak, Mustafa; Citak, Demirhan; Ferreira, Hadla S.; Korn, Maria das Graças Andrade; Bezerra, Marcos de Almeida

    2009-01-01

    Texto completo: acesso restrito. p. 1041-1045 A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L−1 nitric acid solution, the analytes are determinate employing fla...

  11. DETECTION OF CA II ABSORPTION BY A HIGH-VELOCITY CLOUD IN THE DIRECTION OF THE QUASAR PKS 0837-120

    NARCIS (Netherlands)

    ROBERTSON, JG; SCHWARZ, UJ; VANWOERDEN, H; MURRAY, JD; MORTON, DC; HULSBOSCH, ANM

    1991-01-01

    We present optical absorption spectroscopy of the Ca II K and H lines along the sight line to the quasar PKS 0837-120, which lies in the direction of a high-velocity cloud (HVC) detected in H I 21-cm emission at V(LSR) = + 105 km s-1. Our data show Ca II absorption due to the HVC as well as a lower

  12. Mass spectrometric analysis of EPO IEF-PAGE interfering substances in nitrile examination gloves.

    Science.gov (United States)

    Reichel, Christian

    2012-10-01

    Direct detection of doping with recombinant erythropoietins (rhEPO) is accomplished by isoelectric focusing (IEF) or sodium dodecylsulfate (SDS) polyacrylamide gel electrophoresis (PAGE). In a recent publication, Lasne et al. (Electrophoresis 2011, 32, 1444) showed that improper use of nitrile examination gloves during sample collection, sample preparation, and IEF-PAGE may lead to distorted or absent EPO IEF-profiles. In order to clarify which substances are responsible for this observation, a mass spectrometric study on water extractable compounds found in nitrile gloves was performed. Several substance classes were shown to be present, among them polyethylene glycols (PEG), anionic and nonionic surfactants, as well as alcohol ethoxylates and plasticizers. It could be demonstrated that alkylbenzenesulfonates, the main category of detectable anionic detergents, and among them sodium dodecylbenzenesulfonate (SDBS) and its homologs, are the prime reason for the interference of nitrile gloves with EPO IEF-PAGE. Copyright © 2012 John Wiley & Sons, Ltd.

  13. How mass spectrometric approaches applied to bacterial identification have revolutionized the study of human gut microbiota.

    Science.gov (United States)

    Grégory, Dubourg; Chaudet, Hervé; Lagier, Jean-Christophe; Raoult, Didier

    2018-03-01

    Describing the human hut gut microbiota is one the most exciting challenges of the 21 st century. Currently, high-throughput sequencing methods are considered as the gold standard for this purpose, however, they suffer from several drawbacks, including their inability to detect minority populations. The advent of mass-spectrometric (MS) approaches to identify cultured bacteria in clinical microbiology enabled the creation of the culturomics approach, which aims to establish a comprehensive repertoire of cultured prokaryotes from human specimens using extensive culture conditions. Areas covered: This review first underlines how mass spectrometric approaches have revolutionized clinical microbiology. It then highlights the contribution of MS-based methods to culturomics studies, paying particular attention to the extension of the human gut microbiota repertoire through the discovery of new bacterial species. Expert commentary: MS-based approaches have enabled cultivation methods to be resuscitated to study the human gut microbiota and thus to fill in the blanks left by high-throughput sequencing methods in terms of culturing minority populations. Continued efforts to recover new taxa using culture methods, combined with their rapid implementation in genomic databases, would allow for an exhaustive analysis of the gut microbiota through the use of a comprehensive approach.

  14. Forensic Drug Identification, Confirmation, and Quantification Using Fully Integrated Gas Chromatography with Fourier Transform Infrared and Mass Spectrometric Detection (GC-FT-IR-MS).

    Science.gov (United States)

    Lanzarotta, Adam; Lorenz, Lisa; Voelker, Sarah; Falconer, Travis M; Batson, JaCinta S

    2018-05-01

    This manuscript is a continuation of a recent study that described the use of fully integrated gas chromatography with direct deposition Fourier transform infrared detection and mass spectrometric detection (GC-FT-IR-MS) to identify and confirm the presence of sibutramine and AB-FUBINACA. The purpose of the current study was to employ the GC-FT-IR portion of the same instrument to quantify these compounds, thereby demonstrating the ability to identify, confirm, and quantify drug substances using a single GC-FT-IR-MS unit. The performance of the instrument was evaluated by comparing quantitative analytical figures of merit to those measured using an established, widely employed method for quantifying drug substances, high performance liquid chromatography with ultraviolet detection (HPLC-UV). The results demonstrated that GC-FT-IR was outperformed by HPLC-UV with regard to sensitivity, precision, and linear dynamic range (LDR). However, sibutramine and AB-FUBINACA concentrations measured using GC-FT-IR were not significantly different at the 95% confidence interval compared to those measured using HPLC-UV, which demonstrates promise for using GC-FT-IR as a semi-quantitative tool at the very least. The most significant advantage of GC-FT-IR compared to HPLC-UV is selectivity; a higher level of confidence regarding the identity of the analyte being quantified is achieved using GC-FT-IR. Additional advantages of using a single GC-FT-IR-MS instrument for identification, confirmation, and quantification are efficiency, increased sample throughput, decreased consumption of laboratory resources (solvents, chemicals, consumables, etc.), and thus cost.

  15. Anomaly disentanglement on the basis of automatic processing of the aerial gamma-spectrometric survey data

    International Nuclear Information System (INIS)

    Perlovskij, V.A.; Zaika, S.D.; Lomtadze, V.V.

    1976-01-01

    Automated processing airborne gamma spectrometric data has been introduced with the use of the BESM-4 computer. Discrimination of anomalies is effected using a variable interval 200-300 m within which maximum values in the general counting channel and their coordinates are found; reference points are detected too against which one can determine the excess and amplitude of the anomalies. The discriminated anomalies are fixed on printer and charts of anomalies are constructed. The charts and tables characterizing the anomaly help in the identification of its potentialities and hence underlie a decision to start ground works

  16. Interference-free mid-IR laser absorption detection of methane

    International Nuclear Information System (INIS)

    Pyun, Sung Hyun; Cho, Jungwan; Davidson, David F; Hanson, Ronald K

    2011-01-01

    A novel, mid-IR scanned-wavelength laser absorption diagnostic was developed for time-resolved, interference-free, absorption measurement of methane concentration. A differential absorption (peak minus valley) scheme was used that takes advantage of the structural differences of the absorption spectrum of methane and other hydrocarbons. A peak and valley wavelength pair was selected to maximize the differential cross-section (σ peak minus valley ) of methane for the maximum signal-to-noise ratio, and to minimize that of the interfering absorbers. Methane cross-sections at the peak and valley wavelengths were measured over a range of temperatures, 1000 to 2000 K, and pressures 1.3 to 5.4 atm. The cross-sections of the interfering absorbers were assumed constant over the small wavelength interval between the methane peak and valley features. Using this diagnostic, methane concentration time histories during n-heptane pyrolysis were measured behind reflected shock waves in a shock tube. The differential absorption scheme efficiently rejected the absorption interference and successfully recovered the vapor-phase methane concentration. These measurements allowed the comparison with methane concentration time-history simulations derived from a current n-heptane reaction mechanism (Sirjean et al 2009 A high-temperature chemical kinetic model of n-alkane oxidation JetSurF version 1.0)

  17. Gamma-spectrometric surveys in differentiated granites. I: a review of the method and of the geochemical behavior of K, Th and U

    International Nuclear Information System (INIS)

    Ulbrich, Horstpeter Herberto Gustavo Jose; Ulbrich, Mabel Norma Costas; Guimaraes, Gilson Burigo

    2009-01-01

    This contribution is part of a research project on the Neo proterozoic Cunhaporanga Granitic Complex (CGC), cropping out in the Ponta Grossa Arch (Parana state, SE Brazil). An initial study used the gamma-spectrometric data of the Serra do Mar Sul Aero geophysical Project, performed during the 70's for CPRM. Later, terrestrial gamma-spectrometric surveys focused on the study of the differentiated Joaquim Murtinho Granite (JMG) in the NW corner of CGC, and the Serra do Carambei Granite, to the SW. In this paper, the results obtained for JMG are presented in two parts. The first deals with methodology and the presentation of several gamma-spectrometric 'color-scale' maps, indicating that results obtained in granites depend strongly on a climatic factor, given the mobility of K during weathering in subtropical climates with strong rainfalls, also favoring a greater mobility of U. Minerals that are U and Th hosts, documented in granites, are reviewed, together with the weathering processes that control the mobility of K, U and Th in soils. Strong K signals in granitic areas submitted to these climates document the presence of fresh rock and/or effects of hydrothermal alteration, while weak or nil signals are evidence of strong leaching of K during weathering. U and Th will be retained in the residual soils, in part leading to their selective enrichment, also coupled with soil migration to lower topographic levels by colluvial transport. The larger solubility of U (as uranyl ion) allows its liberation under oxidizing conditions, and its migration, limited by the possibility of absorption in newly formed mineral and organic soil phases. Th should be retained almost totally in resistant phases and, when liberated in solution, will mostly be fixed in organic and inorganic soil substances. (author)

  18. Automated atomic absorption spectrometric determination of total arsenic in water and streambed materials

    Science.gov (United States)

    Fishman, M.

    1977-01-01

    An automated method to determine both inorganic and organic forms of arsenic In water, water-suspended mixtures, and streambed materials Is described. Organic arsenic-containing compounds are decomposed by either ultraviolet radiation or by suHurlc acid-potassium persulfate digestion. The arsenic liberated, with Inorganic arsenic originally present, is reduced to arsine with sodium borohydrlde. The arable Is stripped from the solution with the aid of nitrogen and Is then decomposed In a tube furnace heated to 800 ??C which Is placed in the optical path of an atomic absorption spectrometer. Thirty samples per hour can be analyzed to levels of 1 ??g arsenic per liter.

  19. Application of a field flow preconcentration system with a minicolumn packed with amberlite XAD-4/1-(2-pyridylazo)-2-naphtol and a flow injection-flame atomic adsorption spectrometric system for lead determination in sea water

    International Nuclear Information System (INIS)

    Carmen Yebra, M. del; Rodriguez, L.; Puig, L.; Moreno-Cid, A.

    2002-01-01

    A field flow preconcentration technique involving a minicolumn containing Amberlite XAD-4 impregnated with the complexing agent 1-(2-pyridylazo)-2-naphthol was used to preconcentrate lead from seawater. Elution of retained lead on the minicolumns was performed by a flow-injection-flame atomic absorption spectrometric system. Factorial designs have been used to optimize the field flow preconcentration system and the flow injection elution process. Factors such as sample pH, sample flow-rate, eluent concentration and volume (hydrochloric acid), elution flow-rate and minicolumn diameter were considered. The results suggest that the sample flow-rate and the eluent volume are statistically significant factors. The detection limit (3σ) of the procedure was 5 ng/L for a sample volume of 1000 ml. The precision (expressed as relative standard deviation) for eleven independent determinations reached values of 4.0-3.1 % in lead solutions of 50-200 ng/L. This procedure has been successfully applied to the determination of lead in seawater from Galicia (Spain). (author)

  20. Absorption studies

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    Absorption studies were once quite popular but hardly anyone does them these days. It is easier to estimate the blood level of the nutrient directly by radioimmunoassay (RIA). However, the information obtained by estimating the blood levels of the nutrients is not the same that can be obtained from the absorption studies. Absorption studies are primarily done to find out whether some of the essential nutrients are absorbed from the gut or not and if they are absorbed, to determine how much is being absorbed. In the advanced countries, these tests were mostly done to detect pernicious anaemia where vitamin B 12 is not absorbed because of the lack of the intrinsic factor in the stomach. In the tropical countries, ''malabsorption syndrome'' is quire common. In this condition, several nutrients like fat, folic acid and vitamin B 12 are not absorbed. It is possible to study absorption of these nutrients by radioisotopic absorption studies

  1. Alkylation of human serum albumin by sulfur mustard in vitro and in vivo : Mass spectrometric analysis of a cysteine adduct as a sensitive biomarker of exposure

    NARCIS (Netherlands)

    Noort, D.; Hulst, A.G.; Jong, L.P.A. de; Benschop, H.P.

    1999-01-01

    To develop a mass spectrometric assay for the detection of sulfur mustard adducts with human serum albumin, the following steps were performed: quantitation of the binding of the agent to the protein by using [14C] sulfur mustard and analysis of acidic and tryptic digests of albumin from blood after

  2. Specific absorption spectra of hemoglobin at different PO2 levels: potential noninvasive method to detect PO2 in tissues.

    Science.gov (United States)

    Liu, Peipei; Zhu, Zhirong; Zeng, Changchun; Nie, Guang

    2012-12-01

    Hemoglobin (Hb), as one of main components of blood, has a unique quaternary structure. Its release of oxygen is controlled by oxygen partial pressure (PO2). We investigate the specific spectroscopic changes in Hb under different PO2 levels to optimize clinical methods of measuring tissue PO2. The transmissivity of Hb under different PO2 levels is measured with a UV/Vis fiber optic spectrometer. Its plotted absorption spectral curve shows two high absorption peaks at 540 and 576 nm and an absorption valley at 560 nm when PO2 is higher than 100 mm Hg. The two high absorption peaks decrease gradually with a decrease in PO2, whereas the absorption valley at 560 nm increases. When PO2 decreases to approximately 0 mm Hg, the two high absorption peaks disappear completely, while the absorption valley has a hypochromic shift (8 to 10 nm) and forms a specific high absorption peak at approximately 550 nm. The same phenomena can be observed in visible reflectance spectra of finger-tip microcirculation. Specific changes in extinction coefficient and absorption spectra of Hb occur along with variations in PO2, which could be used to explain pathological changes caused by tissue hypoxia and for early detection of oxygen deficiency diseases in clinical monitoring.

  3. Characterization of phenolic and other polar compounds in peel and flesh of pink guava (Psidium guajava L. cv. 'Criolla') by ultra-high performance liquid chromatography with diode array and mass spectrometric detection.

    Science.gov (United States)

    Rojas-Garbanzo, Carolina; Zimmermann, Benno F; Schulze-Kaysers, Nadine; Schieber, Andreas

    2017-10-01

    Pink guava (Psidium guajava L.) is a highly consumed fruit in tropical countries. Despite of interesting research on health effects of this fruit, investigations into the profile of secondary plant metabolites are scarce. In this study, the phenolic compounds in the peel and flesh of pink guava were characterized by ultra-high performance liquid chromatography with diode array and mass spectrometric detection. Sixty phenolic compounds were characterized by MS 2 and classified as ellagitannins, flavones, flavonols, flavanols, proanthocyanidins, dihydrochalcones, and anthocyanidins, and non-flavonoids such as phenolic acid derivatives, stilbenes, acetophenones, and benzophenones. Forty-two polyphenols are reported for the first time in both peel and flesh, and twenty-four compounds were detected for the first time in P. guajava, e.g., phlorizin, nothofagin, astringin, chrysin-C-glucoside, valoneic acid bilactone, cinnamoyl-glucoside, and two dimethoxycinnamoyl-hexosides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Review of procedures involving separation and preconcentration for the determination of cadmium using spectrometric techniques

    International Nuclear Information System (INIS)

    Ferreira, Sergio L.C.; Andrade, Jailson B. de; Korn, Maria das Gracas A.; Pereira, Madson de G.; Lemos, Valfredo A.; Santos, Walter N.L. dos; Rodrigues, Frederico de Medeiros; Souza, Anderson S.; Ferreira, Hadla S.; Silva, Erik G.P. da

    2007-01-01

    Spectrometric techniques for the analysis of trace cadmium have developed rapidly due to the increasing need for accurate measurements at extremely low levels of this element in diverse matrices. This review covers separation and preconcentration procedures, such as electrochemical deposition, precipitation, coprecipitation, solid phase extraction, liquid-liquid extraction (LLE) and cloud point extraction (CPE), and consider the features of the their application with several spectrometric techniques

  5. Low-activity spectrometric gamma-ray logging technique for delineation of coal/rock interfaces in dry blast holes

    International Nuclear Information System (INIS)

    Asfahani, J.; Borsaru, M.

    2007-01-01

    A low-activity spectrometric gamma-ray logging technique is proposed in this paper as a sensitive tool for the delineation of coal/rock interfaces in dry blast holes. The advantages and superiority of this technique over traditional micro-density non-spectrometric gamma-ray tools are demonstrated

  6. Barley husk carbon as the fiber coating for the solid-phase microextraction of twelve pesticides in vegetables prior to gas chromatography-mass spectrometric detection.

    Science.gov (United States)

    Liang, Weiqian; Wang, Juntao; Zang, Xiaohuan; Dong, Wenhuan; Wang, Chun; Wang, Zhi

    2017-03-31

    In this work, a barley husk biomaterial was successfully carbonized by hydrothermal method. The carbon had a high specific surface area and good stability. It was coated onto a stainless steel wire through sol-gel technique to prepare a solid-phase microextraction fiber for the extraction of trace levels of twelve pesticides (tsumacide, fenobucarb, indoxacarb, diethofencarb, thimet, terbufos, malathion, thiamethoxam, imidacloprid, buprofezin, acetamiprid, thiamethoxam) from vegetable samples prior to gas chromatography-mass spectrometric (GC-MS) detection. The main experimental parameters that could influence the extraction efficiency such as extraction time, extraction temperature, sample pH, sample salinity, stirring rate, desorption temperature and desorption time, were investigated. Under the optimized conditions, the linearity was observed in the range of 0.2-75.0μgkg -1 for tomato samples, and 0.3-60.0μgkg -1 for cucumber samples, with the correlation coefficients (r) ranging from 0.9959 to 0.9983. The limits of detection of the method were 0.01-0.05μgkg -1 for tomato samples, and 0.03-0.10μgkg -1 for cucumber samples. The recoveries of the analytes for the method from spiked samples were in the range of 76%-104%, and the precision, expressed as the relative standard deviations, was less than 12%. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Infrared absorption of gaseous ClCS detected with time-resolved Fourier-transform spectroscopy

    International Nuclear Information System (INIS)

    Chu, Li-Kang; Han, Hui-Ling; Lee, Yuan-Pern

    2007-01-01

    A transient infrared absorption spectrum of gaseous ClCS was detected with a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. ClCS was produced upon irradiating a flowing mixture of Cl 2 CS and N 2 or CO 2 with a KrF excimer laser at 248 nm. A transient band in the region of 1160-1220 cm -1 , which diminished on prolonged reaction, is assigned to the C-S stretching (ν 1 ) mode of ClCS. Calculations with density-functional theory (B3P86 and B3LYP/aug-cc-pVTZ) predict the geometry, vibrational wave numbers, and rotational parameters of ClCS. The rotational contour of the spectrum of ClCS simulated based on predicted rotational parameters agrees satisfactorily with experimental observation; from spectral simulation, the band origin is determined to be at 1194.4 cm -1 . Reaction kinetics involving ClCS, CS, and CS 2 are discussed

  8. Determination of Cu, Cd, Pb and Cr in yogurt by slurry sampling electrothermal atomic absorption spectrometry: A case study for Brazilian yogurt.

    Science.gov (United States)

    de Andrade, Camila Kulek; de Brito, Patrícia Micaella Klack; Dos Anjos, Vanessa Egéa; Quináia, Sueli Pércio

    2018-02-01

    A slurry sampling electrothermal atomic absorption spectrometric method is proposed for the determination of trace elements such as Cu, Cr, Cd and Pb in yogurt. The main factors affecting the slurry preparation were optimized: nature and concentration of acid solution and sonication time. The analytical method was validated in-house by calibration, linearity, limits of detection and quantification, precision and accuracy test obtaining satisfactory results in all cases. The proposed method was applied for the determination of Cd, Cr, Cu and Pb in some Brazilian yogurt samples. For these samples, the concentrations ranged from 2.5±0.2 to 12.4±0.2ngg -1 ; 34±3 to 899±7ngg -1 ; <8.3 to 12±1ngg -1 ; and <35.4 to 210±16ngg -1 for Cd, Cu, Cr and Pb, respectively. The daily intake of Cd, Cu, Cr and Pb via consumption of these samples was estimated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tuzen, Mustafa [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey); Soylak, Mustafa [Department of Chemistry, Erciyes University, 38039 Kayseri (Turkey)], E-mail: soylak@erciyes.edu.tr; Citak, Demirhan [Department of Chemistry, Gaziosmanpasa University, 60250 Tokat (Turkey); Ferreira, Hadla S.; Korn, Maria G.A. [Universidade Federal da Bahia, Instituto de Quimica, 40170-290 Salvador (Brazil); Bezerra, Marcos A. [Universidade Estadual do Sudoeste da Bahia, 45200-190 Jequie (Brazil)

    2009-03-15

    A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L{sup -1} nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 {mu}g L{sup -1}, respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 {mu}g L{sup -1}. The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish.

  10. Elimination of the inter-element interferences of iron, gold, molybdenum, tin and antimony when determined in organic solvents by flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Aneva, Zara; Arpadjan, Sonja

    1988-01-01

    The mutual interferences in the flame atomic absorption spectrometric determination of iron, gold, molybdenum, tin and antimony after their extraction - pre-concentration as chloride complexes from platinum solutions into isobutyl methyl ketone are investigated. It is suggested that the interferences are caused by chemical reactions in the flame and are influenced by the flame characteristics. The possibility of eliminating the interferences by addition of long-chain quaternary ammonium salts is discussed. (author)

  11. Anomalies from aerial spectrometric and total count radiometric surveys in the southeastern United States

    International Nuclear Information System (INIS)

    Lee, C.H.; Lawton, D.E.

    1978-01-01

    Aerial radiometric reconnaissance surveys are conducted because of their cost, time, and manpower savings compared to surface studies. Two types of aerial surveys are being flown in the southeastern United States: total count gamma-ray surveys for the Coastal Plains Regional Commission and the US Geological Survey, and differential gamma-ray spectrometric surveys for the US Department of Energy. Anomalous radioactivity detected during aerial surveys is related to higher concentrations of naturally occurring uranium, or to cultural activities, natural causes, or mapping errors which simulate real uranium anomalies. Each anomaly should be ground checked; however, several types of anomalies may be eliminated by evaluation of the aerial data in the office if field time is limited

  12. Mass spectrometric investigation of vinyl-substituted organic boron compounds

    International Nuclear Information System (INIS)

    Tarielashvili, V.O.; Ordzhonikidze, K.G.; Parulava, L.P.; Vakhaniya, G.V.

    1992-01-01

    Mass spectrometric investigation of vinyl-substituted organic compounds was conducted. Ionization was performed by electron shock. Possibility of determining boron isotope content is all analyzed organic boron vinyl-substituted compounds by direct method is shown. This simplifies sufficiently and lowers the price of analysis, improves its accuracy and rapidity

  13. Quantitative analysis of the self-absorption and reemission effects on the emission spectrum of photoluminescence in right-angle excitation—detection configuration

    International Nuclear Information System (INIS)

    Wang Zhen-Hua; Wu Yu-E; Zhang Xin-Zheng; Yun Zhi-Qiang; Li Wei; Xu Jing-Jun

    2013-01-01

    A theoretical approach based on differential radiative transport is proposed to quantitatively analyze the self-absorption and reemission effects on the emission spectrum for right angle excitation—detection photoluminescence measurements, and the wavelength dependence of the reemission effect is taken into account. Simulations and experiments are performed using rhodamine 6G solutions in ethanol as model samples. It is shown that the self-absorption effect is the dominant effect on the detected spectrum by inducing pseudo red-shift and reducing total intensity; whereas the reemission effect partly compensates for signal decrease and also results in an apparent signal gain at the wavelengths without absorption. Both effects decrease with the decrease in the sample concentration and the propagation distance of the emission light inside the sample. We therefore suggest that diluted solutions are required for accurate photoluminescence spectrum measurements and photoluminescence-based measurements

  14. Radio spectrometric survey of un-surveyed areas in Syria

    International Nuclear Information System (INIS)

    Aissa, M.; Al-Hent, R; Jubeli, Y.

    2002-11-01

    The values and distribution of the radioelements e U, e Th, % K and Ur units in the surface geological formations of the west and south sectors of Syrian region, were estimated using carbone gamma ray spectrometric survey. The radiometric maps were prepared, as well as, many geological profiles, cross sections studied in different locations and geochemical samples were analyzed by laboratory gamma ray spectrometry and by x-ray diffractometry, the results of the all sets were compared. In general, the survey shows, low radioelement concentrations in the area, especially on basic rocks (Jabal Al-arab, Hawran) south Syria, and on ultra basic rocks (ophiolitic complex) north-west Syria, but there are some separate anomalous spots were connected with phosphate rocks, detected on cretaceous and Palaeogene age. Some times we noticed high radioelement concentrations haloes associated with fractured zones were already arise from secondary uranium mineralization, as a result of solutions movement through fissures in carbonatic and/or chalk like limestone rocks. finally, the obtained concentrations, represent a background values which has no significant importance for uranium exploration point of view. (author)

  15. UV laser long-path absorption spectroscopy

    Science.gov (United States)

    Dorn, Hans-Peter; Brauers, Theo; Neuroth, Rudolf

    1994-01-01

    Long path Differential Optical Absorption Spectroscopy (DOAS) using a picosecond UV laser as a light source was developed in our institute. Tropospheric OH radicals are measured by their rotational absorption lines around 308 nm. The spectra are obtained using a high resolution spectrograph. The detection system has been improved over the formerly used optomechanical scanning device by application of a photodiode array which increased the observed spectral range by a factor of 6 and which utilizes the light much more effectively leading to a considerable reduction of the measurement time. This technique provides direct measurements of OH because the signal is given by the product of the absorption coefficient and the OH concentration along the light path according to Lambert-Beers law. No calibration is needed. Since the integrated absorption coefficient is well known the accuracy of the measurement essentially depends on the extent to which the OH absorption pattern can be detected in the spectra. No interference by self generated OH radicals in the detection lightpath has been observed. The large bandwidth (greater than 0.15 nm) and the high spectral resolution (1.5 pm) allows absolute determination of interferences by other trace gas absorptions. The measurement error is directly accessible from the absorption-signal to baseline-noise ratio in the spectra. The applicability of the method strongly depends on visibility. Elevated concentrations of aerosols lead to considerable attenuation of the laser light which reduces the S/N-ratio. In the moderately polluted air of Julich, where we performed a number of OH measurement spectra. In addition absorption features of unidentified species were frequently detected. A quantitative deconvolution even of the known species is not easy to achieve and can leave residual structures in the spectra. Thus interferences usually increase the noise and deteriorate the OH detection sensitivity. Using diode arrays for sensitive

  16. Application of Cavity Enhanced Absorption Spectroscopy to the Detection of Nitric Oxide, Carbonyl Sulphide, and Ethane—Breath Biomarkers of Serious Diseases

    Science.gov (United States)

    Wojtas, Jacek

    2015-01-01

    The paper presents one of the laser absorption spectroscopy techniques as an effective tool for sensitive analysis of trace gas species in human breath. Characterization of nitric oxide, carbonyl sulphide and ethane, and the selection of their absorption lines are described. Experiments with some biomarkers showed that detection of pathogenic changes at the molecular level is possible using this technique. Thanks to cavity enhanced spectroscopy application, detection limits at the ppb-level and short measurements time (ethane, respectively. The conducted experiments show that this type of diagnosis would significantly increase chances for effective therapy of some diseases. Additionally, it offers non-invasive and real time measurements, high sensitivity and selectivity as well as minimizing discomfort for patients. For that reason, such sensors can be used in screening for early detection of serious diseases. PMID:26091398

  17. On-line Incorporation of Cloud Point Extraction in Flame Atomic Absorption Spectrometric Determination of Silver

    OpenAIRE

    DALALI, Nasser; JAVADI, Nasrin; AGRAWAL, Yadvendra KUMAR

    2008-01-01

    A cloud point extraction method was incorporated into a flow injection system, coupled with flame atomic absorption spectrometry, for determination of trace amounts of silver. The analyte in the aqueous solution was acidified with 0.2 mol L-1 sulfuric acid and complexed with dithizone. The cloud point extraction was performed using the non-ionic surfactant Triton X-114. After obtaining the cloud point, the surfactant-rich phase containing the dithizonate complex was collected in a m...

  18. Stability and linearity control of spectrometric channels of the Cherenkov counters using controllable units

    International Nuclear Information System (INIS)

    Kollar, D.; Kollarova, L.; Khorvat, P.

    1976-01-01

    A system is elaborated to control stability and linearity of the Cherenkov counter spectrometric channels in an experiment on a magnetic monopole search. Linearity of a light characteristic of a photoelectric multiplier is checked with the help of the calibrated light-strikings of light emitting diodes with flare intensity adjusted by controlling generator voltage across the mercury body. A program algorithm is presented for checking stability and linearity of the Cherenkov counter spectrometric channels which helps to consider the fatigue effects of the photoelectric multiplier resulting from the considerable loads

  19. Organic palladium and palladium-magnesium chemical modifiers in direct determination of lead in fractions from distillation of crude oil by electrothermal atomic absorption analysis

    Science.gov (United States)

    Kowalewska, Zofia; Bulska, Ewa; Hulanicki, Adam

    1999-05-01

    Platinum reforming catalysts are easily poisoned by increased levels of lead, therefore a sensitive atomic absorption spectrometric procedure for lead determination in fractions from crude oil distillation was developed. Lead was present in organic form in the samples analysed therefore the behaviour of various lead compounds (Pb-alkylarylsulphonate, Pb-4-cyclohexanobutyrate, tetraethyllead, Pb in fuel oil) was studied. The best procedure for the determination of lead in different petroleum products, including those containing asphaltenes includes a pretreatment with iodine and methyltrioctylammonium chloride, followed by the use of an organic Pd-Mg modifier. Under these conditions an effective matrix removal is possible at a pyrolysis temperature up to approximately 1100°C and the behaviour of lead present in different forms is unified. The characteristic mass is 11-12 pg Pb, corresponding to a detection limit of 0.25 ng g -1 for 20 μl sample solution. This can be lowered by multiple injection.

  20. Selection and optimization of spectrometric amplifiers for gamma spectrometry: part II - linearity, live time correction factors and software

    International Nuclear Information System (INIS)

    Moraes, Marco Antonio Proenca Vieira de; Pugliesi, Reinaldo

    1996-01-01

    The objective of the present work was to establish simple criteria to choose the best combination of electronic modules to achieve an adequate high resolution gamma spectrometer. Linearity, live time correction factors and softwares of a gamma spectrometric system composed by a Hp Ge detector have been studied by using several kinds of spectrometric amplifiers: Canberra 2021, Canberra 2025, Ortec 673 and Tennelec 244 and the MCA cards Ortec and Nucleus. The results showed low values of integral non-linearity for all spectrometric amplifiers connected to the Ortec and Nucleus boards. The MCA card should be able to correct amplifier dead time for 17 kcps count rates. (author)

  1. Indirect ultraviolet detection of alkaline earth metal ions using an imidazolium ionic liquid as an ultraviolet absorption reagent in ion chromatography.

    Science.gov (United States)

    Liu, Yong-Qiang; Yu, Hong

    2017-04-01

    A convenient and versatile method was developed for the separation and detection of alkaline earth metal ions by ion chromatography with indirect UV detection. The chromatographic separation of Mg 2+ , Ca 2+ , and Sr 2+ was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid as the mobile phase, in which the imidazolium ionic liquid acted as an UV-absorption reagent. The effects of imidazolium ionic liquids, detection wavelength, acids in the mobile phase, and column temperature on the retention of Mg 2+ , Ca 2+ , and Sr 2+ were investigated. The main factors influencing the separation and detection were the background UV absorption reagent and the concentration of hydrogen ion in ion chromatography with indirect UV detection. The successful separation and detection of Mg 2+ , Ca 2+ , and Sr 2+ within 14 min were achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.06, 0.12, and 0.23 mg/L, respectively. A new separation and detection method of alkaline earth metal ions by ion chromatography with indirect UV detection was developed, and the application range of ionic liquids was expanded. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Mass Spectrometric Calibration of Controlled Fluoroform Leak Rate Devices Technique and Uncertainty Analysis

    CERN Document Server

    Balsley, S D; Laduca, C A

    2003-01-01

    Controlled leak rate devices of fluoroform on the order of 10 sup - sup 8 atm centre dot cc sec sup - sup 1 at 25 C are used to calibrate QC-1 War Reserve neutron tube exhaust stations for leak detection sensitivity. Close-out calibration of these tritium-contaminated devices is provided by the Gas Dynamics and Mass Spectrometry Laboratory, Organization 14406, which is a tritium analytical facility. The mass spectrometric technique used for the measurement is discussed, as is the first principals calculation (pressure, volume, temperature and time). The uncertainty of the measurement is largely driven by contributing factors in the determination of P, V and T. The expanded uncertainty of the leak rate measurement is shown to be 4.42%, with a coverage factor of 3 (k=3).

  3. Determination of total arsenic in fish by hydride-generation atomic absorption spectrometry: method validation, traceability and uncertainty evaluation

    Science.gov (United States)

    Nugraha, W. C.; Elishian, C.; Ketrin, R.

    2017-03-01

    Fish containing arsenic compound is one of the important indicators of arsenic contamination in water monitoring. The high level of arsenic in fish is due to absorption through food chain and accumulated in their habitat. Hydride generation (HG) coupled with atomic absorption spectrometric (AAS) detection is one of the most popular techniques employed for arsenic determination in a variety of matrices including fish. This study aimed to develop a method for the determination of total arsenic in fish by HG-AAS. The method for sample preparation from American of Analytical Chemistry (AOAC) Method 999.10-2005 was adopted for acid digestion using microwave digestion system and AOAC Method 986.15 - 2005 for dry ashing. The method was developed and validated using Certified Reference Material DORM 3 Fish Protein for trace metals for ensuring the accuracy and the traceability of the results. The sources of uncertainty of the method were also evaluated. By using the method, it was found that the total arsenic concentration in the fish was 45.6 ± 1.22 mg.Kg-1 with a coverage factor of equal to 2 at 95% of confidence level. Evaluation of uncertainty was highly influenced by the calibration curve. This result was also traceable to International Standard System through analysis of Certified Reference Material DORM 3 with 97.5% of recovery. In summary, it showed that method of preparation and HG-AAS technique for total arsenic determination in fish were valid and reliable.

  4. Preparation and spectrometric identification of amide derivatives with antimalaric

    International Nuclear Information System (INIS)

    Ferreira, E.J.

    1987-01-01

    The structures of polymeric compounds using spectrometric analysis of infrared, ultraviolet and protonic magnetic resonance and 13 C nuclear magnetic resonance are studied. Some structural models are used such as antimalaric-sulfones and pyrimidinic derivatives, and non-polymeric derivatives of active compounds. A comparative analysis on structures less complexes is shown. (M.J.C.). Spectrums 186 p [pt

  5. Uranium absorption study pile

    International Nuclear Information System (INIS)

    Raievski, V.; Sautiez, B.

    1959-01-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF 3 counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10 -6 boron per gr. of uranium) or better. (author) [fr

  6. System for Gamma an X rays fluorescence spectrometric

    International Nuclear Information System (INIS)

    Alonso Abad, D.; Arista Romeu, E.; Bolanos Perez, L. and others

    1997-01-01

    A system for spectrometry of gamma or fluorescence X rays is presented. It sis composed by a Si(Li) semiconductors detector, a charge sensitive preamplifier, a high voltage power supply, a spectrometric amplifier and a monolithic 1024 channels multichannel analyzers or an IBM compatible 4096 channels add - on- card multichannel analyzer. The system can be configured as a 1024 or 4096 channels gamma or fluorescent X rays spectrometer

  7. Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

    International Nuclear Information System (INIS)

    Korecki, P.; Tolkiehn, M.; Dąbrowski, K. M.; Novikov, D. V.

    2011-01-01

    A method for a direct measurement of X-ray projections of the atomic structure is described. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy pattern detected using Nb K fluorescence. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples

  8. Supramolecular fullerene/porphyrin charge transfer interaction studied by absorption spectrophotometric method

    Science.gov (United States)

    Mukherjee, Partha; Bhattacharya (Banerjee), Shrabanti; Nayak, Sandip K.; Chattopadhyay, Subrata; Bhattacharya, Sumanta

    2009-06-01

    A detailed UV-Vis spectrometric and thermodynamic studies were done to look insight into the nature of molecular interactions of the electron donor-acceptor complexes of C60 and C70 with 5,10,15,20-tetrakis(octadecyloxyphenyl)-21H,23H-porphyrin (1) in chloroform and toluene. Charge transfer (CT) absorption bands were located in the visible region and vertical ionization potential of 1 was determined utilizing CT transition energy. Low values of oscillator and transition dipole strengths suggested that the complexes were almost of neutral character in ground states. The high binding constant value for the C70-1 complex indicated high selectivity of 1 molecule towards C70. Experimental as well as theoretically determined of enthalpies of formation value substantiated the trend in K values for fullerene-1 complexes.

  9. A mid-infrared absorption diagnostic for acetylene detection

    KAUST Repository

    KC, Utsav

    2015-05-14

    Acetylene is an important combustion intermediate and plays a critical role in soot formation. Accurate measurements of trace concentrations of acetylene can be very useful in validating hydrocarbon oxidation and soot formation mechanisms. Strongest vibrational band of acetylene near 13.7 μm is probed here to develop a highly sensitive absorption diagnostic. Experiments are carried out behind reflected shock waves to measure absorption cross sections of acetylene near 730 cm−1 over a wide range of temperatures (1000–2200 K) and pressures (1–5 bar). The diagnostic is demonstrated by measuring acetylene formation during the shock-heated pyrolysis and oxidation of propene. © 2015 Springer-Verlag Berlin Heidelberg

  10. High-efficient method for spectrometric data real time processing with increased resolution of a measuring channel

    International Nuclear Information System (INIS)

    Ashkinaze, S.I.; Voronov, V.A.; Nechaev, Yu.I.

    1988-01-01

    Solution of reduction problem as a mean to increase spectrometric tract resolution when it is realized using the digit-by-digit modified method and special strategy, significantly reducing the time of processing, is considered. The results presented confirm that the complex measurement tract plus microcomputer is equivalent to the use of the tract with a higher resolution, and the use of the digit-by-digit modified method permits to process spectrometric information in real time scale

  11. Vitamin D-metabolites from human plasma and mass spectrometric analysis by fast heavy ion induced desorption

    Energy Technology Data Exchange (ETDEWEB)

    Fohlman, J; Peterson, P A [Uppsala Univ. (Sweden). Dept. of Cell Research; Kamensky, I; Hakansson, P; Sundqvist, B [Tandemacceleratorlaboratoriet, Uppsala (Sweden)

    1982-07-01

    D-vitamin metabolites have been isolated from human serum employing chromatographic techniques. The serum carrier protein for vitamin D (DBP) was first isolated by immunosorbent chromatography. Lipid ligands associated with DBP were then extracted with hexane and separated by high pressure liquid chromatography (HPLC). Detection of vitamin D metabolites by their absorbance of ultraviolet light is not sufficiently sensitive to monitor all vitamin D derivatives from a few millilitres of serum. Therefore, further analyses are necessary to quantitative these compounds. We have begun to develop a mass spectrometric method to achieve a reliable, quantitative procedure. As a first step towards this goal a number of pure samples of vitamin D compounds have been studied in a time-of-flight mass spectrometer based on fast heavy ion induced desorption. All vitamin D compounds examined could be detected and identified by their molecular ion and fragment spectra.

  12. Vitamin D-metabolites from human plasma and mass spectrometric analysis by fast heavy ion induced desorption

    International Nuclear Information System (INIS)

    Fohlman, J.; Peterson, P.A.

    1982-01-01

    D-vitamin metabolites have been isolated from human serum employing chromatographic techniques. The serum carrier protein for vitamin D (DBP) was first isolated by immunosorbent chromatography. Lipid ligands associated with DBP were then extracted with hexane and separated by high pressure liquid chromatography (HPLC). Detection of vitamin D metabolites by their absorbance of ultraviolet light is not sufficiently sensitive to monitor all vitamin D derivatives from a few millilitres of serum. Therefore, further analyses are necessary to quantitative these compounds. We have begun to develop a mass spectrometric method to achieve a reliable, quantitative procedure. As a first step towards this goal a number of pure samples of vitamin D compounds have been studied in a time-of-flight mass spectrometer based on fast heavy ion induced desorption. All vitamin D compounds examined could be detected and identified by their molecular ion and fragment spectra. (orig.)

  13. Mass spectrometric protein characterization in proteome analysis using GELoader tip micro-columns packed with various chromatographic material

    International Nuclear Information System (INIS)

    Larsen, M.R.

    2001-01-01

    In the early 90'ies mass spectrometry (MS) was introduced as a tool for identifying proteins in protein sequence databases. Since then it has become an integrated tool in protein characterization and is today routinely used to identify proteins separated by gel electrophoresis. A two-tiered mass spectrometric protein identification strategy has recently been proposed. In the first strategy peptide mass maps obtained from the protein of interest are compared with theoretically derived peptide mass maps from proteins in protein sequence databases. If the protein cannot be identified by this strategy, tandem mass spectrometric sequencing is used to generate enough sequence data to identify the protein in protein sequence databases or expressed sequence tag (EST) databases. However, the above strategies primarily identify a protein relatively to the DNA sequence, in which no information about e.g. post-translational modifications (PTMs) is stored. PTMs are known to modify the function, location, solubility and activity of proteins in the cell, and they are therefore very important for understanding living cells. More than 200 different PTMs are known, of which glycosylation, phosphorylation and proteolytic processing are the most common ones. Mass spectrometric analysis of PTMs on gel-separated proteins requires a higher amount of protein than for identification only. In addition, higher sequence coverage from the peptide mass maps or pre-purification of the modified peptides prior to MS analysis, is necessary for detection of putative modified peptides. In this study a multi-tiered strategy, in which GELoader tip micro-columns packed with increasingly more hydrophobic chromatographic material are used in combination with mass spectrometry, is described. The ultimate aim was to gain increased sequence coverage from peptide mixtures derived from gel-separated proteins, in order to locate modified peptides. Graphite powder is described as an alternative to traditional

  14. Continuous flow hydride generation-atomic fluorescence spectrometric determination and speciation of arsenic in wine

    Energy Technology Data Exchange (ETDEWEB)

    Karadjova, Irina B. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria); Lampugnani, Leonardo [C.N.R. Istituto per i processi chimico-fisici, Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa (Italy)]. E-mail: lampugnani@ipcf.cnr.it; Onor, Massimo [C.N.R. Istituto per i processi chimico-fisici, Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa (Italy); D' Ulivo, Alessandro [C.N.R. Istituto per i processi chimico-fisici, Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa (Italy); Tsalev, Dimiter L. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria)

    2005-07-15

    Methods for the atomic fluorescence spectrometric (AFS) determination of total arsenic and arsenic species in wines based on continuous flow hydride generation (HG) with atomization in miniature diffusion flame (MDF) are described. For hydride-forming arsenic, L-cysteine is used as reagent for pre-reduction and complexation of arsenite, arsenate, monomethylarsonate and dimethylarsinate. Concentrations of hydrochloric acid and tetrahydroborate are optimized in order to minimize interference by ethanol. Procedure permits determination of the sum of these four species in 5-10-fold diluted samples with limit of detection (LOD) 0.3 and 0.6 {mu}g l{sup -1} As in white and red wines, respectively, with precision between 2% and 8% RSD at As levels within 0.5-10 {mu}g l{sup -1}. Selective arsine generation from different reaction media is used for non-chromatographic determination of arsenic species in wines: citrate buffer at pH 5.1 for As(III); 0.2 mol l{sup -1} acetic acid for arsenite + dimethylarsinate (DMA); 8 mol l{sup -1} HCl for total inorganic arsenic [As(III) + As(V)]; and monomethylarsonate (MMA) calculated by difference. Calibration with aqueous and ethanol-matched standard solutions of As(III) is used for 10- and 5-fold diluted samples, respectively. The LODs are 0.4 {mu}g l{sup -1} for As(III) and 0.3 {mu}g l{sup -1} for the other three As species and precision is within 4-8% RSDs. Arsenic species in wine were also determined by coupling of ion chromatographic separation on an anion exchange column and HG-flame AFS detection. Methods were validated by means of recovery studies and comparative analyses by HG-AFS and electrothermal atomic absorption spectrometry after microwave digestion. The LODs were 0.12, 0.27, 0.15 and 0.13 {mu}g l{sup -1} (as As) and RSDs were 2-6%, 5-9%, 3-7% and 2-5% for As(III), As(V), MMA and DMA arsenic species, respectively. Bottled red and white wines from Bulgaria, Republic of Macedonia and Italy were analyzed by non

  15. Continuous flow hydride generation-atomic fluorescence spectrometric determination and speciation of arsenic in wine

    International Nuclear Information System (INIS)

    Karadjova, Irina B.; Lampugnani, Leonardo; Onor, Massimo; D'Ulivo, Alessandro; Tsalev, Dimiter L.

    2005-01-01

    Methods for the atomic fluorescence spectrometric (AFS) determination of total arsenic and arsenic species in wines based on continuous flow hydride generation (HG) with atomization in miniature diffusion flame (MDF) are described. For hydride-forming arsenic, L-cysteine is used as reagent for pre-reduction and complexation of arsenite, arsenate, monomethylarsonate and dimethylarsinate. Concentrations of hydrochloric acid and tetrahydroborate are optimized in order to minimize interference by ethanol. Procedure permits determination of the sum of these four species in 5-10-fold diluted samples with limit of detection (LOD) 0.3 and 0.6 μg l -1 As in white and red wines, respectively, with precision between 2% and 8% RSD at As levels within 0.5-10 μg l -1 . Selective arsine generation from different reaction media is used for non-chromatographic determination of arsenic species in wines: citrate buffer at pH 5.1 for As(III); 0.2 mol l -1 acetic acid for arsenite + dimethylarsinate (DMA); 8 mol l -1 HCl for total inorganic arsenic [As(III) + As(V)]; and monomethylarsonate (MMA) calculated by difference. Calibration with aqueous and ethanol-matched standard solutions of As(III) is used for 10- and 5-fold diluted samples, respectively. The LODs are 0.4 μg l -1 for As(III) and 0.3 μg l -1 for the other three As species and precision is within 4-8% RSDs. Arsenic species in wine were also determined by coupling of ion chromatographic separation on an anion exchange column and HG-flame AFS detection. Methods were validated by means of recovery studies and comparative analyses by HG-AFS and electrothermal atomic absorption spectrometry after microwave digestion. The LODs were 0.12, 0.27, 0.15 and 0.13 μg l -1 (as As) and RSDs were 2-6%, 5-9%, 3-7% and 2-5% for As(III), As(V), MMA and DMA arsenic species, respectively. Bottled red and white wines from Bulgaria, Republic of Macedonia and Italy were analyzed by non-chromatographic and chromatographic procedures and the As

  16. Realisation of a {beta} spectrometer solenoidal and a double {beta} spectrometer at coincidence; Realisation d'un spectrometre {beta} solenoidal et d'un double spectrometre {beta} a coincidence

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-06-15

    The two spectrometers have been achieved to tackle numerous problems of nuclear spectrometry. They possess different fields of application that complete themselves. The solenoidal spectrometer permits the determination of the energy limits of {beta} spectra and of their shape; it also permits the determination of the coefficients of internal conversion and reports {alpha}{sub K} / {alpha}{sub L} and it is especially efficient for the accurate energy levels of the {gamma} rays by photoelectric effect. The double coincidence spectrometer has been conceived to get a good efficiency in coincidence: indeed, the sum of the solid angles used for the {beta} and {gamma} emission is rather little lower to 4{pi} steradians. To get this efficiency, one should have sacrificed a little the resolution that is lower to the one obtained with the solenoidal spectrometer for a same brightness. Each of the elements of the double spectrometer can also be adapted to the study of angular correlations {beta}{gamma} and e{sup -}{gamma}. In this use, it is superior to the thin magnetic lens used up to here. The double spectrometer also permits the survey of the coincidences e{sup -}e{sup -}, e{sup -}{beta} of a equivalent way to a double lens; it can also be consider some adaptation for the survey of the angular correlations e{sup -}e{sup -}, e{sup -}{beta}. Finally, we applied the methods by simple spectrometry and by coincidence spectrometry, to the study of the radiances of the following radioelements: {sup 76}As (26 h), {sup 122}Sb (2,8 j), {sup 124}Sb (60 j), {sup 125}Sb (2,7 years). (M.B.) [French] Les deux spectrometres qui ont ete realises permettent d'aborder un grand nombre de problemes de spectrometrie nucleaire. Ils possedent des champs d'application tres differents qui se completent. Le spectrometre solenoidal permet la determination des energies limites des spectres {beta} et de leur forme; il permet aussi la determination des coefficients de conversion interne et des rapports

  17. New FORTRAN computer programs to acquire and process isotopic mass-spectrometric data

    International Nuclear Information System (INIS)

    Smith, D.H.

    1982-08-01

    The computer programs described in New Computer Programs to Acquire and Process Isotopic Mass Spectrometric Data have been revised. This report describes in some detail the operation of these programs, which acquire and process isotopic mass spectrometric data. Both functional and overall design aspects are addressed. The three basic program units - file manipulation, data acquisition, and data processing - are discussed in turn. Step-by-step instructions are included where appropriate, and each subsection is described in enough detail to give a clear picture of its function. Organization of file structure, which is central to the entire concept, is extensively discussed with the help of numerous tables. Appendices contain flow charts and outline file structure to help a programmer unfamiliar with the programs to alter them with a minimum of lost time

  18. Optical resonance-enhanced absorption-based near-field immunochip biosensor for allergen detection.

    Science.gov (United States)

    Maier, Irene; Morgan, Michael R A; Lindner, Wolfgang; Pittner, Fritz

    2008-04-15

    An optical immunochip biosensor has been developed as a rapid method for allergen detection in complex food matrixes, and its application evaluated for the detection of the egg white allergens, ovalbumin and ovomucoid. The optical near-field phenomenon underlying the basic principle of the sensor design is called resonance-enhanced absorption (REA), which utilizes gold nanoparticles (Au NPs) as signal transducers in a highly sensitive interferometric setup. Using this approach, a novel, simple, and rapid colorimetric solid-phase immunoassay on a planar chip substrate was realized in direct and sandwich assay formats, with a detection system that does not require any instrumentation for readout. Semiquantitative immunochemical responses are directly visible to the naked eye of the analyst. The biosensor shows concentration-dependent color development by capturing antibody-functionalized Au NPs on allergen-coated chips and has a detection limit of 1 ng/mL. To establish a rapid method, we took advantage of the physicochemical microenvironment of the Au NP-antibody bioconjugate to be bound directly over an interacting poly(styrene-methyl methacrylate) interlayer by an immobilized antigen. In the direct assay format, a coating time with allergen of only 5 min under "soft" nondenaturing conditions was sufficient for accurate reproducibility and sensitivity. In conclusion, the REA-based immunochip sensor is easy to fabricate, is reproducible and selective in its performance, has minimal technical requirements, and will enable high-throughput screening of affinity binding interactions in technological and medical applications.

  19. Flame atomic absorption spectrometric determination of trace quantities of cadmium in water samples after cloud point extraction in Triton X-114 without added chelating agents

    International Nuclear Information System (INIS)

    Afkhami, Abbas; Madrakian, Tayyebeh; Siampour, Hajar

    2006-01-01

    A new micell-mediated phase separation method for preconcentration of ultra-trace quantities of cadmium as a prior step to its determination by flame atomic absorption spectrometry has been developed. The method is based on the cloud point extraction (CPE) of cadmium in iodide media with Triton X-114 in the absence of any chelating agent. The optimal extraction and reaction conditions (e.g., acid concentration, iodide concentration, effect of time) were studied, and the analytical characteristics of the method (e.g., limit of detection, linear range, preconcentration, and improvement factors) were obtained. Linearity was obeyed in the range of 3-300 ng mL -1 of cadmium. The detection limit of the method is 1.0 ng mL -1 of cadmium. The interference effect of some anions and cations was also tested. The method was applied to the determination of cadmium in tap water, waste water, and sea water samples

  20. Surface extended x-ray absorption fine structure of low-Z absorbates using fluorescence detection

    International Nuclear Information System (INIS)

    Stoehr, J.; Kollin, E.B.; Fischer, D.A.; Hastings, J.B.; Zaera, F.; Sette, F.

    1985-05-01

    Comparison of x-ray fluorescence yield (FY) and electron yield surface extended x-ray absorption fine structure spectra above the S K-edge for c(2 x 2) S on Ni(100) reveals an order of magnitude higher sensitivity of the FY technique. Using FY detection, thiophene (C 4 H 4 S) chemisorption on Ni(100) is studied with S coverages down to 0.08 monolayer. The molecule dissociates at temperatures as low as 100K by interaction with fourfold hollow Ni sites. Blocking of these sites by oxygen leaves the molecule intact

  1. GBT Detection of Polarization-Dependent HI Absorption and HI Outflows in Local ULIRGs and Quasars

    Science.gov (United States)

    Teng, Stacy H.; Veilleux, Sylvain; Baker, Andrew J.

    2013-01-01

    We present the results of a 21-cm HI survey of 27 local massive gas-rich late-stage mergers and merger remnants with the Green Bank Telescope (GBT). These remnants were selected from the Quasar/ULIRG Evolution Study (QUEST) sample of ultraluminous infrared galaxies (ULIRGs; L(sub 8 - 1000 micron) > 10(exp 12) solar L) and quasars; our targets are all bolometrically dominated by active galactic nuclei (AGN) and sample the later phases of the proposed ULIRG-to-quasar evolutionary sequence. We find the prevalence of HI absorption (emission) to be 100% (29%) in ULIRGs with HI detections, 100% (88%) in FIR-strong quasars, and 63% (100%) in FIR-weak quasars. The absorption features are associated with powerful neutral outflows that change from being mainly driven by star formation in ULIRGs to being driven by the AGN in the quasars. These outflows have velocities that exceed 1500 km/s in some cases. Unexpectedly, we find polarization-dependent HI absorption in 57% of our spectra (88% and 63% of the FIR-strong and FIR-weak quasars, respectively). We attribute this result to absorption of polarized continuum emission from these sources by foreground HI clouds. About 60% of the quasars displaying polarized spectra are radio-loud, far higher than the approx 10% observed in the general AGN population. This discrepancy suggests that radio jets play an important role in shaping the environments in these galaxies. These systems may represent a transition phase in the evolution of gas-rich mergers into "mature" radio galaxies.

  2. An Attempt to automate the lithological classification of rocks using geological, gamma-spectrometric and satellite image datasets

    International Nuclear Information System (INIS)

    Fouad, M. K.; Mielik, M. L.; Gharieb, A. N.

    2004-01-01

    The present study aims essentially at proving that the application of the integrated airborne gamma spectrometric and satellite image data is capable of refining the mapped surface geology, and identification of anomalous zones of radioelement content that could provide favorable exploration targets for radioactive mineralizations.The application of the appropriate statistical technique to correlate between satellite image data and gamma-spectrometric data is of great significance in this respect. Experience shows that Landsat T M data in 7 spectral bands are successfully used in such studies rather than MSS. Multivariate statistical analysis techniques are applied to airborne spectrometric and different spectral Landsat T M data. Reduction of the data from n-dimensionality, both qualitatively as color composite image, and quantitatively, as principal component analysis, is performed using some statistical control parameters. This technique shows distinct efficiency in defining areas where different lit ho facies occur. An area located at the north of the Eastern Desert of Egypt, north of Hurgada town, was chosen to test the proposed technique of integrated interpretation of data of different physical nature. The reduced data are represented and interpreted both qualitatively and quantitatively. The advantages and limitations of applying such technique to the different airborne spectrometric, and Landsat T M data are identified. (authors)

  3. Application of Cavity Enhanced Absorption Spectroscopy to the Detection of Nitric Oxide, Carbonyl Sulphide, and Ethane--Breath Biomarkers of Serious Diseases.

    Science.gov (United States)

    Wojtas, Jacek

    2015-06-17

    The paper presents one of the laser absorption spectroscopy techniques as an effective tool for sensitive analysis of trace gas species in human breath. Characterization of nitric oxide, carbonyl sulphide and ethane, and the selection of their absorption lines are described. Experiments with some biomarkers showed that detection of pathogenic changes at the molecular level is possible using this technique. Thanks to cavity enhanced spectroscopy application, detection limits at the ppb-level and short measurements time (laser and a tunable laser system consisting of an optical parametric oscillator and difference frequency generator. Setup using the first source provided a detection limit of 30 ppb for nitric oxide and 250 ppb for carbonyl sulphide. During experiments employing a second laser, detection limits of 0.9 ppb and 0.3 ppb were obtained for carbonyl sulphide and ethane, respectively. The conducted experiments show that this type of diagnosis would significantly increase chances for effective therapy of some diseases. Additionally, it offers non-invasive and real time measurements, high sensitivity and selectivity as well as minimizing discomfort for patients. For that reason, such sensors can be used in screening for early detection of serious diseases.

  4. Solid-phase extraction of Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) ions from environmental samples by flame atomic absorption spectrometry (FAAS)

    Energy Technology Data Exchange (ETDEWEB)

    Duran, Celal [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Gundogdu, Ali [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Bulut, Volkan Numan [Department of Chemistry, Giresun Faculty of Art and Science, Karadeniz Technical University, 28049 Giresun (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Art and Science, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: soylak@erciyes.edu.tr; Elci, Latif [Department of Chemistry, Faculty of Art and Science, Pamukkale University, 20020 Denizli (Turkey); Sentuerk, Hasan Basri [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Tuefekci, Mehmet [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2007-07-19

    A new method using a column packed with Amberlite XAD-2010 resin as a solid-phase extractant has been developed for the multi-element preconcentration of Mn(II), Co(II), Ni(II), Cu(II), Cd(II), and Pb(II) ions based on their complex formation with the sodium diethyldithiocarbamate (Na-DDTC) prior to flame atomic absorption spectrometric (FAAS) determinations. Metal complexes sorbed on the resin were eluted by 1 mol L{sup -1} HNO{sub 3} in acetone. Effects of the analytical conditions over the preconcentration yields of the metal ions, such as pH, quantity of Na-DDTC, eluent type, sample volume and flow rate, foreign ions etc. have been investigated. The limits of detection (LOD) of the analytes were found in the range 0.08-0.26 {mu}g L{sup -1}. The method was validated by analyzing three certified reference materials. The method has been applied for the determination of trace elements in some environmental samples.

  5. Ammonia detection using hollow waveguide enhanced laser absorption spectroscopy based on a 9.56 μm quantum cascade laser

    Science.gov (United States)

    Li, Jinyi; Yang, Sen; Wang, Ruixue; Du, Zhenhui; Wei, Yingying

    2017-10-01

    Ammonia (NH3) is the most abundant alkalescency trace gas in the atmosphere having a foul odor, which is produced by both natural and anthropogenic sources. Chinese Emission Standard for Odor Pollutants has listed NH3 as one of the eight malodorous pollutants since 1993, specifying the emission concentration less than 1 mg/m3 (1.44ppmv). NH3 detection continuously from ppb to ppm levels is significant for protection of environmental atmosphere and safety of industrial and agricultural production. Tunable laser absorption spectroscopy (TLAS) is an increasingly important optical method for trace gas detection. TLAS do not require pretreatment and accumulation of the concentration of the analyzed sample, unlike, for example, more conventional methods such as mass spectrometry or gas chromatography. In addition, TLAS can provide high precision remote sensing capabilities, high sensitivities and fast response. Hollow waveguide (HWG) has recently emerged as a novel concept serving as an efficient optical waveguide and as a highly miniaturized gas cell. Among the main advantages of HWG gas cell compared with conventional multi-pass gas cells is the considerably decreased sample which facilitates gas exchanging. An ammonia sensor based on TLAS using a 5m HWG as the gas cell is report here. A 9.56μm, continuous-wave, distributed feed-back (DFB), room temperature quantum cascade laser (QCL), is employed as the optical source. The interference-free NH3 absorption line located at 1046.4cm-1 (λ 9556.6nm) is selected for detection by analyzing absorption spectrum from 1045-1047 cm-1 within the ν2 fundamental absorption band of ammonia. Direct absorption spectroscopy (DAS) technique is utilized and the measured spectral line is fitted by a simulation model by HITRAN database to obtain the NH3 concentration. The sensor performance is tested with standard gas and the result shows a 1σ minimum detectable concentration of ammonia is about 200 ppb with 1 sec time resolution

  6. Measurement of fission yields for 232-Th (n,f) at 14,7 MeV by direct gamma spectrometric method

    International Nuclear Information System (INIS)

    Chouak, K.; Berrada, M.; Embarech, K.

    1994-01-01

    Fission yields for the reaction 232-Th (n,f) were measured at 14,7 MeV using the activation technique with direct gamma spectrometric method. Neutrons were produced via the T(d,n) sup 4 He reaction. The neutron fluences were determined relative to the well-known sup 2 sup 7 Al(n,p) sup 2 sup 7 Mg or sup 2 sup 7 Al(n,alpha) sup 2 sup 4 Na cross section, according to the irradiation time. Yields of fission products were determined by measuring the induced gamma ray activities of the irradiated Th foils, using a calibrated Ge(Li) detector. All necessary corrections were taken into account: self absorption, coincidence losses and natural gamma rays. Fifty six cumulative yields were measured and only twenty one corresponding results were found in the literature (Crouch,1977). A satisfactory agreement is observed between our results and the published data with the exception of the masses:A=134 and A=140. 1 tab., 2 refs. (author)

  7. Determination of plutonium-241 half-life by mass spectrometric measurement

    International Nuclear Information System (INIS)

    Hiyama, Takashi; Wada, Yukio; Onishi, Koichi

    1982-01-01

    Much data for Pu-241 half-life have been reported, but these values range from 13.8 years to 15.1 years depending on investigators. In order to define the half-life of Pu-241, the half-life was calculated by analyzing the mass spectrometry data obtained in the author's laboratory over the past six years on Plutonium Isotopic Standard Reference Materials prepared at the National Bureau of Standards (NBS). The sample used for this work consisted of SRM-947 and SRM-948 prepared at NBS. Before mass spectrometric analysis, the plutonium aliquot was separated from its Am-241 daughter by anion exchange chromatography, since Am-241 is not distinguished from Pu-241 in the mass spectrometer. 241 Pu/ 239 Pu and 241 Pu/ 240 Pu ratios were calculated from the values of mass spectrometric measurement. From the relation of log N to time, the half-life of Pu-241 was determined, based on the slope using a least squares fit. The half-life of Pu-241 was estimated to be 14.29+-0.15 years. (Yoshitake, I.)

  8. Contribution to the study and to the development of continuous infrared absorption analyzers; Contribution a l'etude et a la mise au point des analyseurs en continu par absorption infrarouge

    Energy Technology Data Exchange (ETDEWEB)

    Coste, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-12-01

    The continuous infra-red absorption determination of corrosive gases implies the construction of an original single-beam spectrometer. The use of a vibration-rotation line means that the apparatus function has to undergo an alternating displacement: for one position this function is centered on the line, for other position it is placed close by, but away from any absorption. A non-linear relationship is derived between the concentration of the impurity under consideration, the optical density measured at the centre of the line and the total pressure of the gas mixture. The problem is then solved using an associated specific analog computer. The system is applicable to the determination of low concentrations. The principle proposed in then adapted to an analysis using a non-resolved vibration-rotation band. (authors) [French] Le dosage en continu par absorption infrarouge des gaz corrosifs, implique la construction d'un spectrometre original en simple faisceau. L'utilisation d'une raie de vibration - rotation, conduit a effectuer un deplacement alternatif de la fonction d'appareil: pour une position, celle-ci est centree sur la raie, pour l'autre position elle est placee a proximite mais en dehors de toute absorption. On etablit une relation non lineaire entre la concentration de l'impurete consideree, la densite optique mesuree au centre de la raie et la pression totale du melange gazeux. Le probleme est alors resolu par un calculateur analogique specifique associe. Le systeme s'applique au dosage des faibles concentrations. Le principe propose est ensuite adapte a l'analyse a partir d'une bande de vibration - rotation non resolue. (auteurs)

  9. Modeling of detection efficiency of HPGe semiconductor detector by Monte Carlo method

    International Nuclear Information System (INIS)

    Rapant, T.

    2003-01-01

    Over the past ten years following the gradual adoption of new legislative standards for protection against ionizing radiation was significant penetration of gamma-spectrometry between standard radioanalytical methods. In terms of nuclear power plant gamma-spectrometry has shown as the most effective method of determining of the activity of individual radionuclides. Spectrometric laboratories were gradually equipped with the most modern technical equipment. Nevertheless, due to the use of costly and time intensive experimental calibration methods, the possibilities of gamma-spectrometry were partially limited. Mainly in late 90-ies during substantial renovation and modernization works. For this reason, in spectrometric laboratory in Nuclear Power Plants Bohunice in cooperation with the Department of Nuclear Physics FMPI in Bratislava were developed and tested several calibration procedures based on computer simulations using GEANT program. In presented thesis the calibration method for measuring of bulk samples based on auto-absorption factors is described. The accuracy of the proposed method is at least comparable with other used methods, but it surpasses them significantly in terms of efficiency and financial time and simplicity. The described method has been used successfully almost for two years in laboratory spectrometric Radiation Protection Division in Bohunice nuclear power. It is shown by the results of international comparison measurements and repeated validation measurements performed by Slovak Institute of Metrology in Bratislava.

  10. Assessment of current mass spectrometric workflows for the quantification of low abundant proteins and phosphorylation sites

    Directory of Open Access Journals (Sweden)

    Manuel Bauer

    2015-12-01

    Full Text Available The data described here provide a systematic performance evaluation of popular data-dependent (DDA and independent (DIA mass spectrometric (MS workflows currently used in quantitative proteomics. We assessed the limits of identification, quantification and detection for each method by analyzing a dilution series of 20 unmodified and 10 phosphorylated synthetic heavy labeled reference peptides, respectively, covering six orders of magnitude in peptide concentration with and without a complex human cell digest background. We found that all methods performed very similarly in the absence of background proteins, however, when analyzing whole cell lysates, targeted methods were at least 5–10 times more sensitive than directed or DDA methods. In particular, higher stage fragmentation (MS3 of the neutral loss peak using a linear ion trap increased dynamic quantification range of some phosphopeptides up to 100-fold. We illustrate the power of this targeted MS3 approach for phosphopeptide monitoring by successfully quantifying 9 phosphorylation sites of the kinetochore and spindle assembly checkpoint component Mad1 over different cell cycle states from non-enriched pull-down samples. The data are associated to the research article ‘Evaluation of data-dependent and data-independent mass spectrometric workflows for sensitive quantification of proteins and phosphorylation sites׳ (Bauer et al., 2014 [1]. The mass spectrometry and the analysis dataset have been deposited to the ProteomeXchange Consortium (http://proteomecentral.proteomexchange.org via the PRIDE partner repository with the dataset identifier PXD000964.

  11. Targeted selected reaction monitoring mass spectrometric immunoassay for insulin-like growth factor 1.

    Directory of Open Access Journals (Sweden)

    Eric E Niederkofler

    Full Text Available Insulin-like growth factor 1 (IGF1 is an important biomarker of human growth disorders that is routinely analyzed in clinical laboratories. Mass spectrometry-based workflows offer a viable alternative to standard IGF1 immunoassays, which utilize various pre-analytical preparation strategies. In this work we developed an assay that incorporates a novel sample preparation method for dissociating IGF1 from its binding proteins. The workflow also includes an immunoaffinity step using antibody-derivatized pipette tips, followed by elution, trypsin digestion, and LC-MS/MS separation and detection of the signature peptides in a selected reaction monitoring (SRM mode. The resulting quantitative mass spectrometric immunoassay (MSIA exhibited good linearity in the range of 1 to 1,500 ng/mL IGF1, intra- and inter-assay precision with CVs of less than 10%, and lowest limits of detection of 1 ng/mL. The linearity and recovery characteristics of the assay were also established, and the new method compared to a commercially available immunoassay using a large cohort of human serum samples. The IGF1 SRM MSIA is well suited for use in clinical laboratories.

  12. Gamma spectrometric analyses of environmental samples at PINSTECH

    International Nuclear Information System (INIS)

    Faruq, M.U.; Parveen, N.; Ahmed, B.; Aziz, A.

    1979-01-01

    Gamma spectrometric analyses of air and other environmental samples from PINSTECH were carried out. Air particulate samples were analyzed by a Ge(Li) detector on a computer-based multichannel analyzer. Other environmental samples were analyzed by a Na(T1) scintillation detector spectrometer and a multichannel analyzer with manual analysis. Concentration of radionuclides in the media was determined and the sources of their production were identified. Age of the fall out was estimated from the ratios of the fission products. (authors)

  13. The low-ion QSO absorption-line systems

    International Nuclear Information System (INIS)

    Lanzetta, K.M.

    1988-01-01

    Various techniques are used to investigate the class of QSO absorption-line systems that exhibit low-ion absorption lines. Four separate investigations are conducted as follows: Spectroscopy of 32 QSOs at red wavelengths is presented and used to investigate intermediate-redshift MgII absorption. A total of 22 Mg II doublets are detected, from which properties of the Mg II absorbers are derived. Marginal evidence for intrinsic evolution of the number density of the Mg II absorbers with redshift is found. The data are combined with previous observations of C IV and C II seen in the same QSOs at blue wavelengths, and the properties of Mg II- and C IV-selected systems are compared. A sample is constructed of 129 QSOs for which are available published data suitable for detecting absorption-line systems that are optically thick to Lyman continuum radiation. A total of 53 such Lyman-limit systems are found, from which properties of the Lyman-limit systems are derived. It is found that the rate of incidence of the systems does not strongly evolved with redshift. This result is contrasted with the evolution found previously for systems selected on the basis of Mg II absorption. Spectroscopy at red wavelengths of eight QSOs with known damped Lyα absorption systems is presented. Spectroscopic and spectrophotometric observations aimed at detecting molecular hydrogen and dust in the z = 2.796 damped Lyα absorber toward Q1337 + 113 are presented

  14. Analysis of phenolic compounds from different morphological parts of Helichrysum devium by liquid chromatography with on-line UV and electrospray ionization mass spectrometric detection.

    Science.gov (United States)

    Gouveia, Sandra C; Castilho, Paula C

    2009-12-01

    A simple and rapid method has been used for the screening and identification of the main phenolic compounds from Helichrysum devium using high-performance liquid chromatography with on-line UV and electrospray ionization mass spectrometric detection (LC-DAD/ESI-MS(n)). The total aerial parts and different morphological parts of the plant, namely leaves, flowers and stems, were analyzed separately. A total of 34 compounds present in the methanolic extract from Helichrysum devium were identified or tentatively characterized based on their UV and mass spectra and retention times. Three of these compounds were positively identified by comparison with reference standards. The phenolic compounds included derivatives of quinic acid, O-glycosylated flavonoids, a caffeic acid derivative and a protocatechuic acid derivative. The characteristic loss of 206 Da from malonylcaffeoyl quinic acid was used to confirm the malonyl linkage to the caffeoyl group. This contribution presents one of the first reports on the analysis of phenolic compounds from Helichrysum devium using LC-DAD/ESI-MS(n) and highlights the prominence of quinic acid derivatives as the main group of phenolic compounds present in these extracts. We also provide evidence that the methanolic extract from the flowers was significantly more complex when compared to that of other morphological parts. Copyright 2009 John Wiley & Sons, Ltd.

  15. AMS detection of actinides at high mass separation

    Energy Technology Data Exchange (ETDEWEB)

    Steier, Peter; Lachner, Johannes; Priller, Alfred; Winkler, Stephan; Golser, Robin [University of Vienna, Faculty of Physics, Vienna (Austria); Eigl, Rosmarie [Hiroshima University, Earth and Planetary Systems Science, Hiroshima (Japan); Quinto, Francesca [Institut fuer Nukleare Entsorgung, KIT, Eggenstein-Leopoldshafen (Germany); Sakaguchi, Aya [University of Tsukuba, Center for Research in Isotopes and Environmental Dynamics, Tsukuba (Japan)

    2015-07-01

    AMS is the mass spectrometric method with the highest abundance sensitivity, which is a prerequisite for measurement of the long-lived radioisotope {sup 236}U (t{sub 1/2}=23.4 million years). The most successful application so far is oceanography, since anthropogenic {sup 236}U is present in the world oceans at {sup 236}U:{sup 238}U from 10{sup -11} to 10{sup -8}. We have explored methods to increase the sensitivity and thus to reduce the water volume required to 1 L or less, which significantly reduces the sampling effort. High sensitivity is also necessary to address the expected typical natural isotopic ratios on the order {sup 236}U:{sup 238}U = 10{sup -13}, with potential applications in geology. With a second 90 analyzer magnet and a new Time-of-Flight beam line, VERA is robust against chemical impurities in the background, which e.g. allows measuring Pu isotopes directly in a uranium matrix. This simplifies chemical sample preparation for actinide detection, and may illustrate why AMS reaches lower detection limits than other mass spectrometric methods with nominally higher detection efficiency.

  16. Preconcentration and determination of boron in milk, infant formula, and honey samples by solid phase extraction-electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Garcia, I.; Vinas, P.; Romero-Romero, R. [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain); Hernandez-Cordoba, M. [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, E-30071 Murcia (Spain)], E-mail: hcordoba@um.es

    2009-02-15

    This work presents alternative procedures for the electrothermal atomic absorption spectrometric determination of boron in milk, infant formulas, and honey samples. Honey samples (10% m/v) were diluted in a medium containing 1% v/v HNO{sub 3} and 50% v/v H{sub 2}O{sub 2} and introduced in the atomizer. A mixture of 20 {mu}g Pd and 0.5 {mu}g Mg was used for chemical modification. Calibration was carried out using aqueous solutions prepared in the same medium, in the presence of 10% m/v sucrose. The detection limit was 2 {mu}g g{sup -1}, equivalent to three times the standard error of the estimate (s{sub y/x}) of the regression line. For both infant formulas and milk samples, due to their very low boron content, we used a procedure based on preconcentration by solid phase extraction (Amberlite IRA 743), followed by elution with 2 mol L{sup -1} hydrochloric acid. Detection limits were 0.03 {mu}g g{sup -1} for 4% m/v honey, 0.04 {mu}g g{sup -1} for 5% m/v infant formula and 0.08 {mu}g mL{sup -1} for 15% v/v cow milk. We confirmed the accuracy of the procedure by comparing the obtained results with those found via a comparable independent procedure, as well by the analysis of four certified reference materials.

  17. Depth-selective X-ray absorption spectroscopy by detection of energy-loss Auger electrons

    Energy Technology Data Exchange (ETDEWEB)

    Isomura, Noritake, E-mail: isomura@mosk.tytlabs.co.jp [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Soejima, Narumasa; Iwasaki, Shiro [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Nomoto, Toyokazu; Murai, Takaaki [Aichi Synchrotron Radiation Center (AichiSR), 250-3 Minamiyamaguchi-cho, Seto, Aichi 489-0965 (Japan); Kimoto, Yasuji [Toyota Central R& D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan)

    2015-11-15

    Graphical abstract: - Highlights: • A unique XAS method is proposed for depth profiling of chemical states. • PEY mode detecting energy-loss electrons enables a variation in the probe depth. • Si K-edge XAS spectra of the Si{sub 3}N{sub 4}/SiO{sub 2}/Si multilayer films have been investigated. • Deeper information was obtained in the spectra measured at larger energy loss. • Probe depth could be changed by the selection of the energy of detected electrons. - Abstract: A unique X-ray absorption spectroscopy (XAS) method is proposed for depth profiling of chemical states in material surfaces. Partial electron yield mode detecting energy-loss Auger electrons, called the inelastic electron yield (IEY) mode, enables a variation in the probe depth. As an example, Si K-edge XAS spectra for a well-defined multilayer sample (Si{sub 3}N{sub 4}/SiO{sub 2}/Si) have been investigated using this method at various kinetic energies. We found that the peaks assigned to the layers from the top layer to the substrate appeared in the spectra in the order of increasing energy loss relative to the Auger electrons. Thus, the probe depth can be changed by the selection of the kinetic energy of the energy loss electrons in IEY-XAS.

  18. Depth-selective X-ray absorption spectroscopy by detection of energy-loss Auger electrons

    International Nuclear Information System (INIS)

    Isomura, Noritake; Soejima, Narumasa; Iwasaki, Shiro; Nomoto, Toyokazu; Murai, Takaaki; Kimoto, Yasuji

    2015-01-01

    Graphical abstract: - Highlights: • A unique XAS method is proposed for depth profiling of chemical states. • PEY mode detecting energy-loss electrons enables a variation in the probe depth. • Si K-edge XAS spectra of the Si_3N_4/SiO_2/Si multilayer films have been investigated. • Deeper information was obtained in the spectra measured at larger energy loss. • Probe depth could be changed by the selection of the energy of detected electrons. - Abstract: A unique X-ray absorption spectroscopy (XAS) method is proposed for depth profiling of chemical states in material surfaces. Partial electron yield mode detecting energy-loss Auger electrons, called the inelastic electron yield (IEY) mode, enables a variation in the probe depth. As an example, Si K-edge XAS spectra for a well-defined multilayer sample (Si_3N_4/SiO_2/Si) have been investigated using this method at various kinetic energies. We found that the peaks assigned to the layers from the top layer to the substrate appeared in the spectra in the order of increasing energy loss relative to the Auger electrons. Thus, the probe depth can be changed by the selection of the kinetic energy of the energy loss electrons in IEY-XAS.

  19. Mass Spectrometric Identification and Differentiation of Botulinum Neurotoxins through Toxin Proteomics.

    Science.gov (United States)

    Kalb, Suzanne R; Barr, John R

    2013-08-01

    Botulinum neurotoxins (BoNTs) cause the disease botulism, which can be lethal if untreated. There are seven known serotypes of BoNT, A-G, defined by their response to antisera. Many serotypes are distinguished into differing subtypes based on amino acid sequence and immunogenic properties, and some subtypes are further differentiated into toxin variants. Toxin characterization is important as different types of BoNT can respond differently to medical countermeasures for botulism, and characterization of the toxin can aid in epidemiologic and forensic investigations. Proteomic techniques have been established to determine the serotype, subtype, or toxin variant of BoNT. These techniques involve digestion of the toxin into peptides, tandem mass spectrometric (MS/MS) analysis of the peptides, and database searching to identify the BoNT protein. These techniques demonstrate the capability to detect BoNT and its neurotoxin-associated proteins, and differentiate the toxin from other toxins which are up to 99.9% identical in some cases. This differentiation can be accomplished from toxins present in a complex matrix such as stool, food, or bacterial cultures and no DNA is required.

  20. Mass spectrometric investigation of fluorated europium β-diketonates

    International Nuclear Information System (INIS)

    Khomenko, V.S.; Lozinskij, M.O.; Fialkov, Yu.A.; Rasshinina, T.A.; Suboch, V.P.; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)

    1983-01-01

    Ternary complexes of europium with two organic lidands - fluorated β-diketone and organic base - in the aqueous phase at electron shock are investigated; regroupings that take place in them are established. Mass-spectrometric investigation has shown that complexes with β-diketones, containing in oxygen atom in a fluorated radical, eliminate stable molecules of difluorophosgen, CoF 2 . For the complexes studied under the above conditions the Co molecule elimination is also typical which is accompanied by the formation of ions with a metal-carbon bond

  1. Standard methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    All methods described for subsampling and analysis of UF 6 are in routine use at United States Atomic Energy Commission installations. A gravimetric method is included for U and titrimetric methods, for Cl 2 and U. Mass spectrometric methods are given for both double and single standard procedures for U-isotopic content and for semiquantitative determination of hydrocarbons, chlorocarbons, and partially substituted halohydrocarbons. Spectroscopic methods are described for 232 U, fission products, Pu, and Np. In some instances an ion exchange- or extraction-separation is specified prior to the spectroscopic determination. Mass spectroscopic procedures for 31 trace elements are included, as are spectrophotometric methods for Br 2 , Si, P, Ti, V, W, Th, and Mo. Following a preliminary separation for some elements, emission spectroscopic procedures are described for B, Si, Ru, Hf, Mo, Nb, Ta, Ti, W, Zr, V, Th, rare earths, and other elements. Procedures for the determination of Sb, Ru, Al, Cd, Co, Ca, Cr, Fe, Pb, Mg, Mn, Ni, K, Na, and Zn by atomic absorption methods are included. The preparation of high-purity U 3 O 8 by the hydrolysis of UF 6 to UO 2 F 2 which upon drying and pyrohydrolysis yields U 3 O 8 is described

  2. Determination of suvorexant in human plasma using 96-well liquid-liquid extraction and HPLC with tandem mass spectrometric detection.

    Science.gov (United States)

    Breidinger, S A; Simpson, R C; Mangin, E; Woolf, E J

    2015-10-01

    A method, using liquid chromatography with tandem mass spectrometric detection (LC-MS/MS), was developed for the determination of suvorexant (MK-4305, Belsomra(®)), a selective dual orexin receptor antagonist for the treatment insomnia, in human plasma over the concentration range of 1-1000ng/mL. Stable isotope labeled (13)C(2)H3-suvorexant was used as an internal standard. The sample preparation procedure utilized liquid-liquid extraction, in the 96-well format, of a 100μL plasma sample with methyl t-butyl ether. The compounds were chromatographed under isocratic conditions on a Waters dC18 (50×2.1mm, 3μm) column with a mobile phase consisting of 30/70 (v/v %) 10mM ammonium formate, pH3/acetonitrile at a flow rate of 0.3mL/min. Multiple reaction monitoring of the precursor-to-product ion pairs for suvorexant (m/z 451→186) and (13)C(2)H3-suvorexant (m/z 455→190) on an Applied Biosystems API 4000 tandem mass spectrometer was used for quantitation. Intraday assay precision, assessed in six different lots of control plasma, was within 10% CV at all concentrations, while assay accuracy ranged from 95.6 to 105.0% of nominal. Quality control (QC) samples in plasma were stored at -20°C. Initial within day analysis of QCs after one freeze-thaw cycle showed accuracy within 9.5% of nominal with precision (CV) of 6.7% or less. The plasma QC samples were demonstrated to be stable for up to 25 months at -20°C. The method described has been used to support clinical studies during Phase I through III of clinical development. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Mass spectrometric identification of isocyanate-induced modifications of keratins in human skin

    NARCIS (Netherlands)

    Hulst, A.G.; Verstappen, D.R.W.; Riet-van Oeveren, D. van der; Vermeulen, N.P.E.; Noort, D.

    2015-01-01

    In the current paper we show that exposure of human callus to isocyanates leads to covalent modifications within keratin proteins. Mass spectrometric analyses of pronase digests of keratin isolated from exposed callus show that both mono- and di-adducts (for di-isocyanates) are predominantly formed

  4. Detection of cancerous biological tissue areas by means of infrared absorption and SERS spectroscopy of intercellular fluid

    Science.gov (United States)

    Velicka, M.; Urboniene, V.; Ceponkus, J.; Pucetaite, M.; Jankevicius, F.; Sablinskas, V.

    2015-08-01

    We present a novel approach to the detection of cancerous kidney tissue areas by measuring vibrational spectra (IR absorption or SERS) of intercellular fluid taken from the tissue. The method is based on spectral analysis of cancerous and normal tissue areas in order to find specific spectral markers. The samples were prepared by sliding the kidney tissue over a substrate - surface of diamond ATR crystal in case of IR absorption or calcium fluoride optical window in case of SERS. For producing the SERS signal the dried fluid film was covered by silver nanoparticle colloidal solution. In order to suppress fluorescence background the measurements were performed in the NIR spectral region with the excitation wavelength of 1064 nm. The most significant spectral differences - spectral markers - were found in the region between 400 and 1800 cm-1, where spectral bands related to various vibrations of fatty acids, glycolipids and carbohydrates are located. Spectral markers in the IR and SERS spectra are different and the methods can complement each other. Both of them have potential to be used directly during surgery. Additionally, IR absorption spectroscopy in ATR mode can be combined with waveguide probe what makes this method usable in vivo.

  5. Spectrometric aerial survey as a new tool for geological survey and mining prospecting

    International Nuclear Information System (INIS)

    Cambon, R.

    1997-01-01

    Airborne survey for radioactive minerals started around 1945. The limited sensitivity of the tools used, the difficulties found for the topographic and training effect corrections, made difficult the evaluation of the results. The technical progresses realized in the recent past years in electronic and computer sciences allowed to overcome these difficulties and gave to the method all its potentialities. With the aerial spectrometric survey, a new step was made, because this method can be used for other topics than radioactive prospection such as geological survey and mining prospection for metallic and industrial minerals. The spectrometric method is based on the possibility to measure photopeak energies (gamma radiation) emitted by radioactive minerals and discriminate between them those emitted by U238, TI 208 and K40 respectively daughter products of uranium, thorium and potassium. For airborne survey, one consider that measuring instruments will allow to pick-up 80% of the radioactive emission concerning the first 15 to 30 centimetres of ground (1 metre maximum). The use of this method for geological and mineral exploration is based on the assumption that different rock types or ore bearing rock types are composed of certain amounts of rock forming minerals which comprise specific quantities of radioactive elements such as potassium, uranium and thorium (cf: Gabelman 77). To be able to evaluate the results of the spectrometric survey it will be necessary to know roughly the behaviour of the different radioactive elements through a complete geological cycle. (author)

  6. Gamma spectrometric system based on the personal computer Pravetz-83

    International Nuclear Information System (INIS)

    Yanakiev, K; Grigorov, T.; Vuchkov, M.

    1985-01-01

    A gamma spectrometric system based on a personal microcomputer Pravets-85 is described. The analog modules are NIM standard. ADC data are stored in the memory of the computer via a DMA channel and a real-time data processing is possible. The results from a series of tests indicate that the performance of the system is comparable with that of comercially avalable computerized spectrometers Ortec and Canberra

  7. Mercury speciation in environmental solid samples using thermal release technique with atomic absorption detection

    Energy Technology Data Exchange (ETDEWEB)

    Shuvaeva, Olga V. [Institute of Inorganic Chemistry, Academician Lavrent' ev Prospect 3, 630090 Novosbirsk (Russian Federation)], E-mail: olga@che.nsk.su; Gustaytis, Maria A.; Anoshin, Gennadii N. [Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Koptyug Prospect 3, 630090 Novosibirsk (Russian Federation)

    2008-07-28

    A sensitive and very simple method for determination of mercury species in solid samples has been developed involving thermal release analysis in combination with atomic absorption (AAS) detection. The method allows determination of mercury(II) chloride, methylmercury and mercury sulfide at the level of 0.70, 0.35 and 0.20 ng with a reproducibility of the results of 14, 25 and 18%, respectively. The accuracy of the developed assay has been estimated using certified reference materials and by comparison of the results with those of an independent method. The method has been applied for Hg species determination in original samples of lake sediments and plankton.

  8. A measuring generator for testing spectrometric channels

    International Nuclear Information System (INIS)

    Dinh Sy Hien; Kalinkin, A.I.

    1984-01-01

    A measuring generator for testing and tuning an amplitude spectrometric channel is described. The device consists of a pseudo random pulse generator, constructed on shifters, a sawtooth wave generator and a shaper of stable amplitude pulses with exponential decay times. The device is made as CAMAC unit width modules and has the following specifications: average pulse repetition rate of pseudo random pulses is 3.1; 25; 50; 100; 200 kHz; peak amplitude of 2 Hz pulse repetition of saw tooth pulses is 6 V; peak amplitude of exponential shape pulses is 5 V. The block-diagram and basic circuits of the device are given

  9. Validation of an analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals in soil.

    Science.gov (United States)

    Frentiu, Tiberiu; Ponta, Michaela; Hategan, Raluca

    2013-03-01

    The aim of this paper was the validation of a new analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals (Ag, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil after microwave assisted digestion in aqua regia. Determinations were performed on the ContrAA 300 (Analytik Jena) air-acetylene flame spectrometer equipped with xenon short-arc lamp as a continuum radiation source for all elements, double monochromator consisting of a prism pre-monocromator and an echelle grating monochromator, and charge coupled device as detector. For validation a method-performance study was conducted involving the establishment of the analytical performance of the new method (limits of detection and quantification, precision and accuracy). Moreover, the Bland and Altman statistical method was used in analyzing the agreement between the proposed assay and inductively coupled plasma optical emission spectrometry as standardized method for the multielemental determination in soil. The limits of detection in soil sample (3σ criterion) in the high-resolution continuum source flame atomic absorption spectrometry method were (mg/kg): 0.18 (Ag), 0.14 (Cd), 0.36 (Co), 0.25 (Cr), 0.09 (Cu), 1.0 (Ni), 1.4 (Pb) and 0.18 (Zn), close to those in inductively coupled plasma optical emission spectrometry: 0.12 (Ag), 0.05 (Cd), 0.15 (Co), 1.4 (Cr), 0.15 (Cu), 2.5 (Ni), 2.5 (Pb) and 0.04 (Zn). Accuracy was checked by analyzing 4 certified reference materials and a good agreement for 95% confidence interval was found in both methods, with recoveries in the range of 94-106% in atomic absorption and 97-103% in optical emission. Repeatability found by analyzing real soil samples was in the range 1.6-5.2% in atomic absorption, similar with that of 1.9-6.1% in optical emission spectrometry. The Bland and Altman method showed no statistical significant difference between the two spectrometric

  10. [Detecting Thallium in Water Samples using Dispersive Liquid Phase Microextraction-Graphite Furnace Atomic Absorption Spectroscopy].

    Science.gov (United States)

    Zhu, Jing; Li, Yan; Zheng, Bo; Tang, Wei; Chen, Xiao; Zou, Xiao-li

    2015-11-01

    To develope a method of solvent demulsification dispersive liquid phase microextraction (SD-DLPME) based on ion association reaction coupled with graphite furnace atomic absorption spectroscopy (GFAAS) for detecting thallium in water samples. Methods Thallium ion in water samples was oxidized to Tl(III) with bromine water, which reacted with Cl- to form TlCl4-. The ionic associated compound with trioctylamine was obtained and extracted. DLPME was completed with ethanol as dispersive solvent. The separation of aqueous and organic phase was achieved by injecting into demulsification solvent without centrifugation. The extractant was collected and injected into GFAAS for analysis. With palladium colloid as matrix modifier, a two step drying and ashing temperature programming process was applied for high precision and sensitivity. The linear range was 0.05-2.0 microg/L, with a detection limit of 0.011 microg/L. The relative standard derivation (RSD) for detecting Tl in spiked water sample was 9.9%. The spiked recoveries of water samples ranged from 94.0% to 103.0%. The method is simple, sensitive and suitable for batch analysis of Tl in water samples.

  11. A spectrometrical method to measure the deuterium content in 2H-enriched water

    International Nuclear Information System (INIS)

    Dumke, I.

    1980-04-01

    A test method and spectrometer has been developed for emission-spectrometrical measurement of the deuterium content in water enriched with deuterium. The water sample is melted into a previously evacuated glas tube and a gas discharge is excited in vapour over the cooled sample to adjust to a low vapour pressure with high frequency. The intensities of the H(α) and D(α) lines appearing in the spectrum determine the D-content. Both lines were resolved by a Fabry-Perot interferometer and geometrically separated fed to two photodetectors. The remaining spectrum is filtered off. Following electronic calculation of the signals, the measured value is indicated which has to be corrected by a standard curve. The relative measuring accuracy is about +-1% for enrichments of over 1% D and less than +-5% in the region of 0.3-1% D. The detection limit is about 0.03% D (sample amount: 50 μl, average of 5 samples). (orig./HP) [de

  12. Gamma-spectrometric analysis of river sediments collected around phosphate fertilizer industries

    International Nuclear Information System (INIS)

    Gallardo, M.C.; Garcia-Leon, M.; Mundi, M.; Respaldiza, M.A.

    1993-01-01

    Gamma-ray spectrometric analysis has been carried out on sediments collected in an estuarine system formed by two major rivers in southern Spain. The results show clearly that important amounts of natural radioactivity are accumulating on the bed of both rivers. This radioactivity appears to originate from effluent from several phoshate fertilizer factories adjacent to the estuary. (author)

  13. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide powder and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Total Carbon by Combustion and Gravimetry 7-17 Total Boron by Titrimetry 18-28 Isotopic Composition by Mass Spectrometry 29-38 Chloride and Fluoride Separation by Pyrohydrolysis 39-45 Chloride by Constant-Current Coulometry 46-54 Fluoride by Ion-Selective Electrode 55-63 Water by Constant-Voltage Coulometry 64-72 Impurities by Spectrochemical Analysis 73-81 Soluble Boron by Titrimetry 82-95 Soluble Carbon by a Manometric Measurement 96-105 Metallic Impurities by a Direct Reader Spectrometric Method 106-114

  14. Validation of a stability-indicating spectrometric method for the determination of sulfacetamide sodium in pure form and ophthalmic preparations

    Directory of Open Access Journals (Sweden)

    Sofia Ahmed

    2017-01-01

    Full Text Available Introduction: Sulfacetamide sodium is a widely used sulfonamide for ophthalmic infections. Objective: A number of analytical methods have been reported for the analysis of sulfacetamide but they lack the ability to determine both the active drug and its major degradation product, sulfanilamide, simultaneously in a sample. Materials and Methods: In the present study a simple, rapid and economical stability-indicating UV spectrometric method has been validated for the simultaneous assay of sulfacetamide sodium and sulfanilamide in pure form and in ophthalmic preparations. Results: The method has been found to be accurate (recovery 100.03 ±0.589% and precise (RSD 0.587% with detectable and quantifiable limits of 1.67×10–6 M (0.04 mg% and 5.07×10–6 M (0.13 mg%, respectively for the assay of pure sulfacetamide sodium. The method is also found to be accurate and precise to small changes in wavelength, pH and buffer concentration as well as to forced degradation. The study further includes the validation of the method for the assay of pure sulfanilamide in solution, which has been found to be accurate, precise and robust. Conclusion: The results indicate that the proposed two-component spectrometric method is stability-indicating and can be used for the simultaneous assay of both sulfacetamide sodium and sulfanilamide in synthetic mixtures and degraded solutions.

  15. Ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometric for selenium speciation in foods and beverages.

    Science.gov (United States)

    Tuzen, Mustafa; Pekiner, Ozlem Zeynep

    2015-12-01

    A rapid and environmentally friendly ultrasound assisted ionic liquid dispersive liquid liquid microextraction (USA-IL-DLLME) was developed for the speciation of inorganic selenium in beverages and total selenium in food samples by using graphite furnace atomic absorption spectrometry. Some analytical parameters including pH, amount of complexing agent, extraction time, volume of ionic liquid, sample volume, etc. were optimized. Matrix effects were also investigated. Enhancement factor (EF) and limit of detection (LOD) for Se(IV) were found to be 150 and 12 ng L(-1), respectively. The relative standard deviation (RSD) was found 4.2%. The accuracy of the method was confirmed with analysis of LGC 6010 Hard drinking water and NIST SRM 1573a Tomato leaves standard reference materials. Optimized method was applied to ice tea, soda and mineral water for the speciation of Se(IV) and Se(VI) and some food samples including beer, cow's milk, red wine, mixed fruit juice, date, apple, orange, grapefruit, egg and honey for the determination of total selenium. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. 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

  17. Optical Path Length Calibration: A Standard Approach for Use in Absorption Cell-Based IR-Spectrometric Gas Analysis

    Directory of Open Access Journals (Sweden)

    Javis Anyangwe Nwaboh

    2014-01-01

    Full Text Available We employed a comparison method to determine the optical path length of gas cells which can be used in spectroscopic setup based on laser absorption spectroscopy or FTIR. The method is based on absorption spectroscopy itself. A reference gas cell, whose length is a priori known and desirably traceable to the international system of units (SI, and a gas mixture are used to calibrate the path length of a cell under test. By comparing spectra derived from pressure-dependent measurements on the two cells, the path length of the gas cell under test is determined. The method relies neither on the knowledge of the gas concentration nor on the line strength parameter of the probed transition which is very rarely traceable to the SI and of which the uncertainty is often relatively large. The method is flexible such that any infrared light source and infrared active molecule with isolated lines can be used. We elaborate on the method, substantiate the method by reporting results of this calibration procedure applied to multipass and single pass gas cells of lengths from 0.38 m to 21 m, and compare this to other methods. The relative combined uncertainty of the path length results determined using the comparison method was found to be in the ±0.4% range.

  18. Synoptic view of the different domains of application of airborne radiometric and spectrometric surveys in egypt

    International Nuclear Information System (INIS)

    Fouad, K.M.

    1998-01-01

    Airborne radiometric survey has been applied for more than three decades in egypt. Experience gained from the acquired data over different geological environments has revealed the importance of this geophysical tool in: 1. disclosure of anomalies of potential uranium deposits, 2. geological mapping, 3. environmental monitoring of natural radiometric background around nuclear facilities, as well as the detection of nuclear fallout resulting from local or foreign nuclear activities. The advent of recording of the discriminated gamma ray energies in the airborne 256-channel spectrometer has eventually resulted in the quantitative detection of uranium, thorium, and potassium and their elemental ratios in the rocks. This has greatly widened the scope of geophysical and geochemical application. When this type is coupled with airborne magnetometry, the geological and structural configuration is appreciably revealed in three dimensions. The important role played by the statistical method of analysis is also shown. Case histories from the eastern desert, and sinai peninsula, are exhibited to help manifest the wide variety of applications of radiometric and spectrometric surveys

  19. 2DB: a Proteomics database for storage, analysis, presentation, and retrieval of information from mass spectrometric experiments.

    Science.gov (United States)

    Allmer, Jens; Kuhlgert, Sebastian; Hippler, Michael

    2008-07-07

    The amount of information stemming from proteomics experiments involving (multi dimensional) separation techniques, mass spectrometric analysis, and computational analysis is ever-increasing. Data from such an experimental workflow needs to be captured, related and analyzed. Biological experiments within this scope produce heterogenic data ranging from pictures of one or two-dimensional protein maps and spectra recorded by tandem mass spectrometry to text-based identifications made by algorithms which analyze these spectra. Additionally, peptide and corresponding protein information needs to be displayed. In order to handle the large amount of data from computational processing of mass spectrometric experiments, automatic import scripts are available and the necessity for manual input to the database has been minimized. Information is in a generic format which abstracts from specific software tools typically used in such an experimental workflow. The software is therefore capable of storing and cross analysing results from many algorithms. A novel feature and a focus of this database is to facilitate protein identification by using peptides identified from mass spectrometry and link this information directly to respective protein maps. Additionally, our application employs spectral counting for quantitative presentation of the data. All information can be linked to hot spots on images to place the results into an experimental context. A summary of identified proteins, containing all relevant information per hot spot, is automatically generated, usually upon either a change in the underlying protein models or due to newly imported identifications. The supporting information for this report can be accessed in multiple ways using the user interface provided by the application. We present a proteomics database which aims to greatly reduce evaluation time of results from mass spectrometric experiments and enhance result quality by allowing consistent data handling

  20. 2DB: a Proteomics database for storage, analysis, presentation, and retrieval of information from mass spectrometric experiments

    Directory of Open Access Journals (Sweden)

    Hippler Michael

    2008-07-01

    Full Text Available Abstract Background The amount of information stemming from proteomics experiments involving (multi dimensional separation techniques, mass spectrometric analysis, and computational analysis is ever-increasing. Data from such an experimental workflow needs to be captured, related and analyzed. Biological experiments within this scope produce heterogenic data ranging from pictures of one or two-dimensional protein maps and spectra recorded by tandem mass spectrometry to text-based identifications made by algorithms which analyze these spectra. Additionally, peptide and corresponding protein information needs to be displayed. Results In order to handle the large amount of data from computational processing of mass spectrometric experiments, automatic import scripts are available and the necessity for manual input to the database has been minimized. Information is in a generic format which abstracts from specific software tools typically used in such an experimental workflow. The software is therefore capable of storing and cross analysing results from many algorithms. A novel feature and a focus of this database is to facilitate protein identification by using peptides identified from mass spectrometry and link this information directly to respective protein maps. Additionally, our application employs spectral counting for quantitative presentation of the data. All information can be linked to hot spots on images to place the results into an experimental context. A summary of identified proteins, containing all relevant information per hot spot, is automatically generated, usually upon either a change in the underlying protein models or due to newly imported identifications. The supporting information for this report can be accessed in multiple ways using the user interface provided by the application. Conclusion We present a proteomics database which aims to greatly reduce evaluation time of results from mass spectrometric experiments and enhance

  1. Evidence for pion absorption on four nucleons

    International Nuclear Information System (INIS)

    Rzehorz, B.; Backenstoss, G.; Dzemidzic, M.; Zagreb Univ.; Furic, M.; Zagreb Univ.; Hoffart, A.; Petkovic, T.; Zagreb Univ.; Ullrich, H.; Weyer, H.J.; Weiser, D.; Wildi, M.

    1996-01-01

    Experimental spectra from the coincident detection of three nucleons after the pion absorption in 4 He are displayed. The presence of a mechanism with four nucleons participating in the absorption process is made obvious. The total cross-sections for this absorption mode are: σ 4NA abs =(1.0±0.2)mb at T π =120 MeV and σ 4NA abs =(2.18± 0.65) mb at T π =210 MeV. (orig.)

  2. Buffer-gas-induced absorption resonances in Rb vapor

    International Nuclear Information System (INIS)

    Mikhailov, Eugeniy E.; Novikova, Irina; Rostovtsev, Yuri V.; Welch, George R.

    2004-01-01

    We observe transformation of the electromagnetically induced transparency (EIT) resonance into an absorption resonance in a Λ interaction configuration in a cell filled with 87 Rb and a buffer gas. This transformation occurs as one-photon detuning of the coupling fields is varied from the atomic transition. No such absorption resonance is found in the absence of a buffer gas. The width of the absorption resonance is several times smaller than the width of the EIT resonance, and the changes of absorption near these resonances are about the same. Similar absorption resonances are detected in the Hanle configuration in a buffered cell

  3. Gas chromatographic-mass spectrometric determination of hydrophilic compounds in environmental water by solid-phase extraction with activated carbon fiber felt.

    Science.gov (United States)

    Kawata, K; Ibaraki, T; Tanabe, A; Yagoh, H; Shinoda, A; Suzuki, H; Yasuhara, A

    2001-03-09

    Simple gas chromatographic-mass spectrometric determination of hydrophilic organic compounds in environmental water was developed. A cartridge containing activated carbon fiber felt was made by way of trial and was evaluated for solid-phase extraction of the compounds in water. The hydrophilic compounds investigated were acrylamide, N,N-dimethylacetamide, N,N-dimethylformamide, 1,4-dioxane, furfural, furfuryl alcohol, N-nitrosodiethylamine and N-nitrosodimethylamine. Overall recoveries were good (80-100%) from groundwater and river water. The relative standard deviations ranged from 4.5 to 16% for the target compounds. The minimum detectable concentrations were 0.02 to 0.03 microg/l. This method was successfully applied to several river water samples.

  4. Radiochemical separation and alpha-spectrometric determination of Americium in different matrixes

    International Nuclear Information System (INIS)

    Radenkovic, M.; Joksic, J.; Paligoric, D.

    2009-01-01

    A method of separation and alpha-spectrometric determination of americium, developed in VINCA Institute of Nuclear Sciences is described in the paper. The procedure is convenient to be used for 241 Am determination in environmental matrixes as well as samples of human origin if a very small concentrations are expected, using 243 Am as a tracer for radiochemical yield recovery. (author) [sr

  5. Sensitive emission spectrometric method for the analysis of airborne particulate matter

    International Nuclear Information System (INIS)

    Sugimae, A.

    1975-01-01

    A rapid and sensitive emission spectrometric method for the routine analysis of airborne particulate matter collected on the glass fiber filter is reported. The method is a powder--dc arc technique involving no chemical pre-enrichment procedures. The elements--Ag, BA: Be, Bi, Cd, Co, Cr, Cu, Fe, Ga, La, Mn, Ni, Pb, Sn, V, Y, Yb, and Zn--were determined. (U.S.)

  6. Parallel workflow for high-throughput (>1,000 samples/day quantitative analysis of human insulin-like growth factor 1 using mass spectrometric immunoassay.

    Directory of Open Access Journals (Sweden)

    Paul E Oran

    Full Text Available Insulin-like growth factor 1 (IGF1 is an important biomarker for the management of growth hormone disorders. Recently there has been rising interest in deploying mass spectrometric (MS methods of detection for measuring IGF1. However, widespread clinical adoption of any MS-based IGF1 assay will require increased throughput and speed to justify the costs of analyses, and robust industrial platforms that are reproducible across laboratories. Presented here is an MS-based quantitative IGF1 assay with performance rating of >1,000 samples/day, and a capability of quantifying IGF1 point mutations and posttranslational modifications. The throughput of the IGF1 mass spectrometric immunoassay (MSIA benefited from a simplified sample preparation step, IGF1 immunocapture in a tip format, and high-throughput MALDI-TOF MS analysis. The Limit of Detection and Limit of Quantification of the resulting assay were 1.5 μg/L and 5 μg/L, respectively, with intra- and inter-assay precision CVs of less than 10%, and good linearity and recovery characteristics. The IGF1 MSIA was benchmarked against commercially available IGF1 ELISA via Bland-Altman method comparison test, resulting in a slight positive bias of 16%. The IGF1 MSIA was employed in an optimized parallel workflow utilizing two pipetting robots and MALDI-TOF-MS instruments synced into one-hour phases of sample preparation, extraction and MSIA pipette tip elution, MS data collection, and data processing. Using this workflow, high-throughput IGF1 quantification of 1,054 human samples was achieved in approximately 9 hours. This rate of assaying is a significant improvement over existing MS-based IGF1 assays, and is on par with that of the enzyme-based immunoassays. Furthermore, a mutation was detected in ∼1% of the samples (SNP: rs17884626, creating an A→T substitution at position 67 of the IGF1, demonstrating the capability of IGF1 MSIA to detect point mutations and posttranslational modifications.

  7. Thermogravimetric-quadrupole mass-spectrometric analysis of geochemical samples.

    Science.gov (United States)

    Gibson, E. K., Jr.; Johnson, S. M.

    1972-01-01

    Thermogravimetric-quadrupole mass-spectrometric-analysis techniques can be used to study a wide variety of problems involving decomposition processes and identification of released volatile components. A recording vacuum thermoanalyzer has been coupled with a quadrupole mass spectrometer. The rapid scan capabilities of the quadrupole mass spectrometer are used to identify the gaseous components released. The capability of the thermogravimetric-quadrupole mass spectrometer to provide analytical data for identification of the released volatile components, for determination of their sequence of release and for correlation of thermal-decomposition studies is illustrated by an analysis of the Orgueil carbonaceous chondrite.

  8. Dansyl-peptides matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) and tandem mass spectrometric (MS/MS) features improve the liquid chromatography/MALDI-MS/MS analysis of the proteome.

    Science.gov (United States)

    Chiappetta, Giovanni; Ndiaye, Sega; Demey, Emmanuelle; Haddad, Iman; Marino, Gennaro; Amoresano, Angela; Vinh, Joëlle

    2010-10-30

    Peptide tagging is a useful tool to improve matrix-assisted laser desorption/ionization tandem mass spectrometric (MALDI-MS/MS) analysis. We present a new application of the use of the dansyl chloride (DNS-Cl). DNS-Cl is a specific primary amine reagent widely used in protein biochemistry. It adds a fluorescent dimethylaminonaphthalene moiety to the molecule. The evaluation of MALDI-MS and MS/MS analyses of dansylated peptides shows that dansylation raises the ionization efficiency of the most hydrophilic species compared with the most hydrophobic ones. Consequently, higher Mascot scores and protein sequence coverage are obtained by combining MS and MS/MS data of native and tagged samples. The N-terminal DNS-Cl sulfonation improves the peptide fragmentation and promotes the generation of b-fragments allowing better peptide sequencing. In addition, we set up a labeling protocol based on the microwave chemistry. Peptide dansylation proved to be a rapid and cheap method to improve the performance of liquid chromatography (LC)/MALDI-MS/MS analysis at the proteomic scale in terms of peptide detection and sequence coverage. Copyright © 2010 John Wiley & Sons, Ltd.

  9. Electrospray Ionization Mass Spectrometric Analysis of Highly Reactive Glycosyl Halides

    Directory of Open Access Journals (Sweden)

    Lajos Kovács

    2012-07-01

    Full Text Available Highly reactive glycosyl chlorides and bromides have been analysed by a routine mass spectrometric method using electrospray ionization and lithium salt adduct-forming agents in anhydrous acetonitrile solution, providing salient lithiated molecular ions [M+Li]+, [2M+Li]+ etc. The role of other adduct-forming salts has also been evaluated. The lithium salt method is useful for accurate mass determination of these highly sensitive compounds.

  10. Mass spectrometric investigation of fluorated europium. beta. -diketonates. [Electrons

    Energy Technology Data Exchange (ETDEWEB)

    Khomenko, V.S.; Lozinskij, M.O.; Fialkov, Yu.A.; Rasshinina, T.A.; Suboch, V.P. (AN Belorusskoj SSR, Minsk. Inst. Fiziki; AN Ukrainskoj SSR, Kiev. Inst. Organicheskoj Khimii)

    Ternary complexes of europium with two organic ligands - fluorated ..beta..-diketone and organic base - in the aqueous phase at electron shock are investigated; regroupings that take place in them are established. Mass-spectrometric investigation has shown that complexes with ..beta..-diketones, containing in oxygen atom in a fluorated radical, eliminate stable molecules of difluorophosgen, CoF/sub 2/. For the complexes studied under the above conditions the Co molecule elimination is also typical which is accompanied by the formation of ions with a metal-carbon bond.

  11. Determination of uranium enrichment by using gamma-spectrometric methods

    International Nuclear Information System (INIS)

    Kutnyj, D.V.; Telegin, Yu.N.; Odejchuk, N.P.; Mikhailov, V.A.; Tovkanets, V.E.

    2009-01-01

    By using commercial analysis programs MGAU (LLNL, USA) and FRAM (LANL, USA) the summary error of gamma-spectrometric uranium enrichment measurements was investigated. Uranium samples with enrichments of 0,71; 4,46 and 20,1 % were measured. The coaxial high purity germanium detector (type GC) and the planar germanium detector (type LEGe) were used as gamma-radiation detectors. It was shown that experimental equipment and mathematical software available in NSC KIPT allow us to measure uranium enrichment by nondestructive method with accuracy of not worse than 2%.

  12. Smartphone spectroscopy: three unique modalities for point-of-care testing

    Science.gov (United States)

    Long, Kenneth D.; Yu, Hojeong; Cunningham, Brian T.

    2015-06-01

    Here we demonstrate three principle modalities for a smartphone-based spectrometer: absorption, fluorescence, and photonic crystal (PC)-based label-free detection. When combined with some simple optical components, the rear-facing CMOS camera in a mobile device can provide spectrometric data that rivals that of laboratory instruments, but at a fraction of the cost. The use of a smartphone-based platform poses significant advantages based upon the rise of smartphone apps, which allow for user-interface and data-processing algorithms to be packaged and distributed within environments that are externally maintained with potential for integration with services such as cloud storage, GIS-tagging, and remote expert analysis. We demonstrate the absorption modality of our device by performing an enzyme-linked immunosorbent assay (ELISA) on both a cancer biomarker and a peanut allergen, demonstrating clinically relevant limits of detection (LOD). Second, we demonstrate the success of a molecular beacon (MB)-based assay on the smartphone platform, achieving an LOD of 1.3 pM for a specific RNA sequence, less than that of a commercial benchtop instrument. Finally, we use a PC biosensor to perform label-free detection of a representative biological interaction: Protein A and human immunoglobulin G (IgG) in the nanomolar regime. Our work represents the first demonstration of smartphone-based spectroscopy for biological assays, and the first mobile-device-enabled detection instrument that serves to measure three distinct sensing modalities (label-free biosensing, absorption spectroscopy, and fluorescence spectroscopy). The smartphone platform has the potential to expand the use of spectrometric analysis to environments assay from the laboratory, which may include rural or remote locations, low-resource settings, and consumer markets.

  13. The interlaboratory experiment IDA-72 on mass spectrometric isotope dilution analysis. Vol. 2

    International Nuclear Information System (INIS)

    Beyrich, W.; Drosselmeyer, E.

    1975-07-01

    Volume II of the report on the IDA-72 experiment contains papers written by different authors on a number of special topics connected with the preparation, performance and evaluation of the interlaboratory test. In detail the sampling procedures for active samples of the reprocessing plant and the preparation of inactive reference and spike solution from standard material are described as well as new methods of sample conditioning by evaporation. An extra chapter is devoted to the chemical sample treatment as a preparation for mass spectrometric analysis of the U and Pu content of the solutions. Special topics are also methods for mass discrimination corrections, α-spectrometer measurements as a supplement for the determination of Pu-238 and the comparison of concentration determinations by mass spectrometric isotope dilution analysis with those performed by X-ray fluorescence spectrometry. The last part of this volume contains papers connected with the computerized statistical evaluation of the high number of data. (orig.) [de

  14. Terahertz gas sensor based on absorption-induced transparency

    Directory of Open Access Journals (Sweden)

    Rodrigo Sergio G.

    2016-01-01

    Full Text Available A system for the detection of spectral signatures of gases at the Terahertz regime is presented. The system consists in an initially opaque holey metal film whereby the introduction of a gas provokes the appearance of spectral features in transmission and reflection, due to the phenomenom of absorption-induced transparency (AIT. The peaks in transmission and dips in reflection observed in AIT occur close to the absorption energies of the molecules, hence its name. The presence of the gas would be thus revealed as a strong drop in reflectivity measurements at one (or several of the gas absorption resonances. As a proof of principle, we theoretically demonstrate how the AIT-based sensor would serve to detect tiny amounts of hydrocyanic acid.

  15. Gamma-spectrometric examination of hot particles emitted during the Chernobyl accident

    International Nuclear Information System (INIS)

    Balashazy, I.; Szabadine-Szende, G.; Loerinc, M.; Zombori, P.

    1987-05-01

    Ge(Li) gamma-spectrometric examination of hot particles prepared from air filtered dust of Budapest air after the Chernobyl accident is presented. The method of separating hot particles is described and their concentration in the air is determined. The radioactive isotope composition of hot particles is discussed and compared with that of dust samples. Finally, the inhalation probability and radiation burden of hot particles are evaluated. (author)

  16. Quantitative mass-spectrometric analysis of hydrogen helium isotope mixtures

    International Nuclear Information System (INIS)

    Langer, U.

    1998-12-01

    This work deals with the mass-spectrometric method for the quantitative analysis of hydrogen-helium-isotope mixtures, with special attention to fusion plasma diagnostics. The aim was to use the low-resolution mass spectrometry, a standard measuring method which is well established in science and industry. This task is solved by means of the vector mass spectrometry, where a mass spectrum is repeatedly measured, but with stepwise variation of the parameter settings of a quadruple mass spectrometer. In this way, interfering mass spectra can be decomposed and, moreover, it is possible to analyze underestimated mass spectra of complex hydrogen-helium-isotope mixtures. In this work experimental investigations are presented which show that there are different parameters which are suitable for the UMS-method. With an optimal choice of the parameter settings hydrogen-helium-isotope mixtures can be analyzed with an accuracy of 1-3 %. In practice, a low sensitivity for small helium concentration has to be noted. To cope with this task, a method for selective hydrogen pressure reduction has been developed. Experimental investigations and calculations show that small helium amounts (about 1 %) in a hydrogen atmosphere can be analyzed with an accuracy of 3 - 10 %. Finally, this work deals with the effects of the measuring and calibration error on the resulting error in spectrum decomposition. This aspect has been investigated both in general mass-spectrometric gas analysis and in the analysis of hydrogen-helium-mixtures by means of the vector mass spectrometry. (author)

  17. Uranium absorption study pile; Empilement pour le controle de l'absorption de l'uranium

    Energy Technology Data Exchange (ETDEWEB)

    Raievski, V; Sautiez, B [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The report describes a pile designed to measure the absorption of fuel slugs. The pile is of graphite and comprises a central section composed of uranium rods in a regular lattice. RaBe sources and BF{sub 3} counters are situated on either side of the center. A given uranium charge is compared with a specimen charge of about 560 kg, and the difference in absorption between the two noted. The sensitivity of the equipment will detect absorption variations of about a few ppm boron (10{sup -6} boron per gr. of uranium) or better. (author) [French] Nous decrivons un dispositif permettant de mesurer l'absorption des elements combustibles d'une pile. Ce dispositif est constitue par un empilement de graphite dont la region centrale est formee par un reseau regulier de barres d'uranium. Des sources de RaBe et des compteurs a BF{sub 3} sont places de part et d'autre de cette region. En comparant un chargement d'uranium a un chargement etalon d'environ 560 kg, on peut determiner la difference d'absorption entre ces deux chargements. La sensibilite permettrait de deceler une variation d'absorption de l'ordre du ppm de bore (10{sup -6} g de bore par gramme d'uranium) et peut-etre mieux. (auteur)

  18. UV Absorption Spectroscopy in Water-Filled Antiresonant Hollow Core Fibers for Pharmaceutical Detection.

    Science.gov (United States)

    Nissen, Mona; Doherty, Brenda; Hamperl, Jonas; Kobelke, Jens; Weber, Karina; Henkel, Thomas; Schmidt, Markus A

    2018-02-06

    Due to a worldwide increased use of pharmaceuticals and, in particular, antibiotics, a growing number of these substance residues now contaminate natural water resources and drinking supplies. This triggers a considerable demand for low-cost, high-sensitivity methods for monitoring water quality. Since many biological substances exhibit strong and characteristic absorption features at wavelengths shorter than 300 nm, UV spectroscopy presents a suitable approach for the quantitative identification of such water-contaminating species. However, current UV spectroscopic devices often show limited light-matter interaction lengths, demand sophisticated and bulky experimental infrastructure which is not compatible with microfluidics, and leave large fractions of the sample analyte unused. Here, we introduce the concept of UV spectroscopy in liquid-filled anti-resonant hollow core fibers, with large core diameters and lengths of approximately 1 m, as a means to overcome such limitations. This extended light-matter interaction length principally improves the concentration detection limit by two orders of magnitude while using almost the entire sample volume-that is three orders of magnitude smaller compared to cuvette based approaches. By integrating the fibers into an optofluidic chip environment and operating within the lowest experimentally feasible transmission band, concentrations of the application-relevant pharmaceutical substances, sulfamethoxazole (SMX) and sodium salicylate (SS), were detectable down to 0.1 µM (26 ppb) and 0.4 µM (64 ppb), respectively, with the potential to reach significantly lower detection limits for further device integration.

  19. UV Absorption Spectroscopy in Water-Filled Antiresonant Hollow Core Fibers for Pharmaceutical Detection

    Directory of Open Access Journals (Sweden)

    Mona Nissen

    2018-02-01

    Full Text Available Due to a worldwide increased use of pharmaceuticals and, in particular, antibiotics, a growing number of these substance residues now contaminate natural water resources and drinking supplies. This triggers a considerable demand for low-cost, high-sensitivity methods for monitoring water quality. Since many biological substances exhibit strong and characteristic absorption features at wavelengths shorter than 300 nm, UV spectroscopy presents a suitable approach for the quantitative identification of such water-contaminating species. However, current UV spectroscopic devices often show limited light-matter interaction lengths, demand sophisticated and bulky experimental infrastructure which is not compatible with microfluidics, and leave large fractions of the sample analyte unused. Here, we introduce the concept of UV spectroscopy in liquid-filled anti-resonant hollow core fibers, with large core diameters and lengths of approximately 1 m, as a means to overcome such limitations. This extended light-matter interaction length principally improves the concentration detection limit by two orders of magnitude while using almost the entire sample volume—that is three orders of magnitude smaller compared to cuvette based approaches. By integrating the fibers into an optofluidic chip environment and operating within the lowest experimentally feasible transmission band, concentrations of the application-relevant pharmaceutical substances, sulfamethoxazole (SMX and sodium salicylate (SS, were detectable down to 0.1 µM (26 ppb and 0.4 µM (64 ppb, respectively, with the potential to reach significantly lower detection limits for further device integration.

  20. A biosorption system for metal ions on Penicillium italicum - loaded on Sepabeads SP 70 prior to flame atomic absorption spectrometric determinations

    International Nuclear Information System (INIS)

    Mendil, Durali; Tuzen, Mustafa; Soylak, Mustafa

    2008-01-01

    A solid phase extraction (SPE) preconcentration system, coupled to a flame atomic absorption spectrometer (FAAS), was developed for the determination of copper(II), cadmium(II), lead(II), manganese(II), iron(III), nickel(II) and cobalt(II) ions at the μg L -1 levels on Penicillium italicum - loaded on Sepabeads SP 70. The analytes were adsorbed on biosorbent at the pH range of 8.5-9.5. The adsorbed metals were eluted with 1 mol L -1 HCl. The influences of the various analytical parameters including pH of the aqueous solutions, sample volume, flow rates were investigated for the retentions of the analyte ions. The recovery values are ranged from 95-102%. The influences of alkaline, earth alkaline and some transition metal ions were also discussed. Under the optimized conditions, the detection limits (3 s, n = 21) for analytes were in the range of 0.41 μg L -1 (cadmium) and 1.60 μg L -1 (iron). The standard reference materials (IAEA 336 Lichen, NIST SRM 1573a Tomato leaves) were analyzed to verify the proposed method. The method was successfully applied for the determinations of analytes in natural water, cultivated mushroom, lichen (Bryum capilare Hedw), moss (Homalothecium sericeum) and refined table salt samples

  1. A biosorption system for metal ions on Penicillium italicum - loaded on Sepabeads SP 70 prior to flame atomic absorption spectrometric determinations

    Energy Technology Data Exchange (ETDEWEB)

    Mendil, Durali; Tuzen, Mustafa [Gaziosmanpasa University, Faculty of Science and Arts, Chemistry Department, 60250 Tokat (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Science and Arts, Chemistry Department, 38039 Kayseri (Turkey)], E-mail: msoylak@gmail.com

    2008-04-15

    A solid phase extraction (SPE) preconcentration system, coupled to a flame atomic absorption spectrometer (FAAS), was developed for the determination of copper(II), cadmium(II), lead(II), manganese(II), iron(III), nickel(II) and cobalt(II) ions at the {mu}g L{sup -1} levels on Penicillium italicum - loaded on Sepabeads SP 70. The analytes were adsorbed on biosorbent at the pH range of 8.5-9.5. The adsorbed metals were eluted with 1 mol L{sup -1} HCl. The influences of the various analytical parameters including pH of the aqueous solutions, sample volume, flow rates were investigated for the retentions of the analyte ions. The recovery values are ranged from 95-102%. The influences of alkaline, earth alkaline and some transition metal ions were also discussed. Under the optimized conditions, the detection limits (3 s, n = 21) for analytes were in the range of 0.41 {mu}g L{sup -1} (cadmium) and 1.60 {mu}g L{sup -1} (iron). The standard reference materials (IAEA 336 Lichen, NIST SRM 1573a Tomato leaves) were analyzed to verify the proposed method. The method was successfully applied for the determinations of analytes in natural water, cultivated mushroom, lichen (Bryum capilare Hedw), moss (Homalothecium sericeum) and refined table salt samples.

  2. Spectral interferences in atomic absorption spectrometry, (5)

    International Nuclear Information System (INIS)

    Daidoji, Hidehiro

    1979-01-01

    Spectral interferences were observed in trace element analysis of concentrated solutions by atomic absorption spectrometry. Molecular absorption and emission spectra for strontium chloride and nitrate, barium chloride and nitrate containing 12 mg/ml of metal ion in airacetylene flame were measured in the wavelength range from 200 to 700 nm. The absorption and emission spectra of SrO were centered near 364.6 nm. The absorption spectra of SrOH around 606.0, 671.0 and 682.0 nm were very strong. And, emission spectrum of BaOH in the wavelength range from 480 to 550 nm was stronger. But, the absorption of this band spectrum was very weak. In the wavelength range from 200 to 400 nm, some unknown bands of absorption were observed for strontium and barium. Absorption spectra of SrCl and BaCl were observed in the argon-hydrogen flame. Also, in the carbon tube atomizer, the absorption spectra of SrCl and BaCl were detected clearly in the wavelength range from 185 to 400 nm. (author)

  3. Neutron activation and mass spectrometric measurement of /sup 129/I

    International Nuclear Information System (INIS)

    Strebin, R.S. Jr.; Brauer, F.P.; Kaye, J.H.; Rapids, M.S.; Stoffels, J.J.

    1987-11-01

    An integrated procedure has been developed for measurement of /sup 129/I by neutron activation analysis and mass spectrometry. An iodine isolation procedure previously used for neutron activation has been modified to provide separated iodine suitable for mass spectrometric measurement as well. Agreement between both methods has been achieved within error limits. The measurement limit by each method is about 10/sup 7/ atoms (2 fg) of /sup 129/I. 13 refs,. 4 figs., 1 tab

  4. Detection of nanocrystallinity by X-ray absorption spectroscopy in thin film transition metal/rare-earth atom, elemental and complex oxides

    International Nuclear Information System (INIS)

    Edge, L.F.; Schlom, D.G.; Stemmer, S.; Lucovsky, G.; Luning, J.

    2006-01-01

    Nanocrystallinity has been detected in the X-ray absorption spectra of transition metal and rare-earth oxides by (i) removal of d-state degeneracies in the (a) Ti and Sc L 3 spectra of TiO 2 and LaScO 3 , respectively, and (b) O K 1 spectra of Zr(Hf)O 2 , Y 2 O 3 , LaScO 3 and LaAlO 3 , and by the (ii) detection of the O-atom vacancy in the O K 1 edge ZrO 2 -Y 2 O 3 alloys. Spectroscopic detection is more sensitive than X-ray diffraction with a limit of ∼2 nm as compared to >5 mm. Other example includes detection of ZrO 2 nanocrystallinity in phase-separated Zr(Hf) silicate alloys

  5. An indirect atomic absorption spectrometric determination of ciprofloxacin, amoxycillin and diclofenac sodium in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    MAHMOUD MOHAMED ISSA

    2008-05-01

    Full Text Available A highly sensitive indirect atomic absorption spectrophotometric (AAS method has been developed for the determination of very low concentrations of ciprofloxacin, amoxycillin and diclofenac sodium. The method is based on the oxidation of these drugs with iron(III. The excess of iron(III was extracted into diethyl ether and then the iron(II in the aqueous layer was aspirated into an air–acetylene flame and determined by AAS. The linear concentration ranges were 25–400, 50–500 and 60–600 ng ml-1 for ciprofloxacin, amoxycillin and diclofenac sodium, respectively. The results were statistically compared with the official method using t- and f-test at p < 0.05. There were insignificant interferences from most of the excipients present. The intra- and inter-day assay coefficients of variation were less than 6.1 % and the recoveries ranged from 95 to 103 %. The method was applied for the analysis of these drug substances in their commercial pharmaceutical formulations.

  6. Cloud point extraction and flame atomic absorption spectrometric determination of cadmium(II), lead(II), palladium(II) and silver(I) in environmental samples

    International Nuclear Information System (INIS)

    Ghaedi, Mehrorang; Shokrollahi, Ardeshir; Niknam, Khodabakhsh; Niknam, Ebrahim; Najibi, Asma; Soylak, Mustafa

    2009-01-01

    The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of cadmium(II), lead(II), palladium(II) and silver(I). The analytical procedure involved the formation of understudy metals complex with bis((1H-benzo [d] imidazol-2yl)ethyl) sulfane (BIES), and quantitatively extracted to the phase rich in octylphenoxypolyethoxyethanol (Triton X-114) after centrifugation. Methanol acidified with 1 mol L -1 HNO 3 was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The concentration of BIES, pH and amount of surfactant (Triton X-114) was optimized. At optimum conditions, the detection limits of (3 sdb/m) of 1.4, 2.8, 1.6 and 1.4 ng mL -1 for Cd 2+ , Pb 2+ , Pd 2+ and Ag + along with preconcentration factors of 30 and enrichment factors of 48, 39, 32 and 42 for Cd 2+ , Pb 2+ , Pd 2+ and Ag + , respectively, were obtained. The proposed cloud point extraction has been successfully applied for the determination of metal ions in real samples with complicated matrix such as radiology waste, vegetable, blood and urine samples.

  7. Microwave assisted synthesis of a novel optical chemosensor for selective Fe{sup 3+} detection

    Energy Technology Data Exchange (ETDEWEB)

    Saleem, Muhammad [Department of Chemistry, Kongju National University, Gongju, Chungnam 314-701 (Korea, Republic of); Kang, Sung Kwon [Department of Chemistry Chungnam National University, Daejeon 305-754 (Korea, Republic of); Lee, Ki Hwan, E-mail: khlee@kongju.ac.kr [Department of Chemistry, Kongju National University, Gongju, Chungnam 314-701 (Korea, Republic of)

    2015-06-15

    Recently, there has been significant interest in the design and development of optical chemosensors for recognition of biologically and environmentally important analytes with high selectivity, sensitivity and low detection-limit because of their fundamental role in medical, environmental and biological applications. Herein, a novel fluorogenic signaling probe 6 for the selective detection of ferric ion in mixed aqueous organic media has been developed through microwave assisted Schiff base formation by reacting 4-amino-3-(2-fluorobenzyl)-1H-1,2,4-triazole-5(4H)-thione 5 with thiophene-2-carbaldehyde. The formation of probe 6 was characterized by FT-IR, {sup 1}H NMR, {sup 13}C NMR, mass spectrometric and single crystal X-ray diffraction analysis. The photophysical results of (Z)-3-(2-fluorobenzyl)-4-[(thiophen-2-ylmethylene) amino]-1H-1,2,4-triazole-5(4H)-thione (6) corroborates its applicability as optical sensing platform for selective Fe{sup 3+} detection in pure organic as well as mixed organic-aqueous media. Through fluorescence titration at 478 nm, we were confirmed that the ligand 6 exhibited remarkable decline in the fluorescence intensity by complexation between 6 and Fe{sup 3+} while it appeared negligible fluorescent quenching in case of the competitive ions in MeOH/water (8:2, v/v, pH 7) at ambient temperature. Meanwhile, the emergence of a new characteristic redshifted signal at 357 nm with gradual increment in the absorption intensity on gentle increase in the ferric ion concentration and continuous shifting in the ligand absorption bands after Fe{sup 3+} addition ascribed the conformational changes in the ligand structure upon Fe{sup 3+} binding. Due to simplicity, low cost, fast response time, considerable sensitivity and robustness, the proposed sensing method might be a practical tool for environmental samples analysis and biological studies. - Highlights: • A novel fluorogenic signaling probe for ferric ion has been developed. • The ligand

  8. Mass-spectrometric investigation of rare earth acetylacetonates dipivaloylmethanates and their adducts

    International Nuclear Information System (INIS)

    Gavrishzhuk, E.M.; Dzyubenko, N.G.; Martynenko, L.I.

    1985-01-01

    Peculiarities of fragmentation of molecular ions of rare earth acetylacetonates and dipivaloylmethanates under mass-spectrometric investigation of these compounds as well as their adducts with o-phenanthroline, α,α'-dipyridyl, triphenylphosphine oxide are considered in the given review. Similar data for identical derivants of some transitions metals are presented. Data on potentials of appearance and dissociation energy of basic ions in mass-spectra of the studied β-diketonates are analyzed

  9. Tunable Diode Laser Absorption Spectroscopy Sensor for Calibration Free Humidity Measurements in Pure Methane and Low CO2 Natural Gas.

    Science.gov (United States)

    Nwaboh, Javis Anyangwe; Pratzler, Sonja; Werhahn, Olav; Ebert, Volker

    2017-05-01

    We report a new direct tunable diode laser absorption spectroscopy (dTDLAS) sensor for absolute measurements of H 2 O in methane, ethane, propane, and low CO 2 natural gas. The sensor is operated with a 2.7 µm DFB laser, equipped with a high pressure single pass gas cell, and used to measure H 2 O amount of substance fractions in the range of 0.31-25 000 µmol/mol. Operating total gas pressures are up to 5000 hPa. The sensor has been characterized, addressing the traceability of the spectrometric results to the SI and the evaluation of the combined uncertainty, following the guide to the expression of uncertainty in measurement (GUM). The relative reproducibility of H 2 O amount of substance fraction measurements at 87 µmol/mol is 0.26% (0.23 µmol/mol). The maximum precision of the sensor was determined using a H 2 O in methane mixture, and found to be 40 nmol/mol for a time resolution of 100 s. This corresponds to a normalized detection limit of 330 nmol mol -1 ·m Hz -1/2 . The relative combined uncertainty of H 2 O amount fraction measurements delivered by the sensor is 1.2%.

  10. Spectrometric storage device in VME standard; Spektrometricheskoe zapominayushchee ustrojstvo v standarte VME

    Energy Technology Data Exchange (ETDEWEB)

    Rezaev, V E

    1996-12-31

    Paper describes module of histogram Memory Module designed to implement hardware way of accumulation of spectrometric data in systems based on VME standard equipment. Application of HMM module enables to increase throughput of the system for data acquisition and processing as in this case VME bus trunk is not occupied and may be used to control experiment course. 2 figs.

  11. DETECTING THE WARM-HOT INTERGALACTIC MEDIUM THROUGH X-RAY ABSORPTION LINES

    Energy Technology Data Exchange (ETDEWEB)

    Yao Yangsen; Shull, J. Michael; Cash, Webster [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Wang, Q. Daniel, E-mail: yaoys@colorado.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2012-02-20

    The warm-hot intergalactic medium (WHIM) at temperatures 10{sup 5}-10{sup 7} K is believed to contain 30%-50% of the baryons in the local universe. However, all current X-ray detections of the WHIM at redshifts z > 0 are of low statistical significance ({approx}< 3{sigma}) and/or controversial. In this work, we aim to establish the detection limits of current X-ray observatories and explore requirements for next-generation X-ray telescopes for studying the WHIM through X-ray absorption lines. We analyze all available grating observations of Mrk 421 and obtain spectra with signal-to-noise ratios (S/Ns) of {approx}90 and 190 per 50 mA spectral bin from Chandra and XMM-Newton observations, respectively. Although these spectra are two of the best ever collected with Chandra and XMM-Newton, we cannot confirm the two WHIM systems reported by Nicastro et al. in 2005. Our bootstrap simulations indicate that spectra with such high S/N cannot constrain the WHIM with O VII column densities N{sub Ovii}{approx}10{sup 15} cm{sup -2} (corresponding to an equivalent width of 2.5 mA for a Doppler velocity of 50 km s{sup -1}) at {approx}> 3{sigma} significance level. The simulation results also suggest that it would take >60 Ms for Chandra and 140 Ms for XMM-Newton to measure the N{sub Ovii} at {>=}4{sigma} from a spectrum of a background QSO with flux of {approx}0.2 mCrab (1 Crab = 2 Multiplication-Sign 10{sup -8} erg s{sup -1} cm{sup -2} at 0.5-2 keV). Future X-ray spectrographs need to be equipped with spectral resolution R {approx} 4000 and effective area A {>=} 100 cm{sup 2} to accomplish the similar constraints with an exposure time of {approx}2 Ms and would require {approx}11 Ms to survey the 15 QSOs with flux {approx}> 0.2 mCrab along which clear intergalactic O VI absorbers have been detected.

  12. Gas detection system

    International Nuclear Information System (INIS)

    Allan, C.J.; Bayly, J.G.

    1975-01-01

    The gas detection system provides for the effective detection of gas leaks over a large area. It includes a laser which has a laser line corresponding to an absorption line of the gas to be detected. A He-Xe laser scans a number of retroreflectors which are strategically located around a D 2 O plant to detect H 2 S leaks. The reflected beam is focused by a telescope, filtered, and passed into an infrared detector. The laser may be made to emit two frequencies, one of which corresponds with an H 2 S absorption line; or it may be modulated on and off the H 2 S absorption line. The relative amplitude of the absorbed light will be a measure of the H 2 S present

  13. Validation of a UV Spectrometric Method for the Assay of Tolfenamic Acid in Organic Solvents

    Directory of Open Access Journals (Sweden)

    Sofia Ahmed

    2015-01-01

    Full Text Available The present study has been carried out to validate a UV spectrometric method for the assay of tolfenamic acid (TA in organic solvents. TA is insoluble in water; therefore, a total of thirteen commonly used organic solvents have been selected in which the drug is soluble. Fresh stock solutions of TA in each solvent in a concentration of 1 × 10−4 M (2.62 mg% were prepared for the assay. The method has been validated according to the guideline of International Conference on Harmonization and parameters like linearity, range, accuracy, precision, sensitivity, and robustness have been studied. Although the method was found to be efficient for the determination of TA in all solvents on the basis of statistical data 1-octanol, followed by ethanol and methanol, was found to be comparatively better than the other studied solvents. No change in the stock solution stability of TA has been observed in each solvent for 24 hours stored either at room (25±1°C or at refrigerated temperature (2–8°C. A shift in the absorption maxima has been observed for TA in various solvents indicating drug-solvent interactions. The studied method is simple, rapid, economical, accurate, and precise for the assay of TA in different organic solvents.

  14. Techniques For Measuring Absorption Coefficients In Crystalline Materials

    Science.gov (United States)

    Klein, Philipp H.

    1981-10-01

    Absorption coefficients smaller than 0.001 cm-1 can, with more or less difficulty, be measured by several techniques. With diligence, all methods can be refined to permit measurement of absorption coefficients as small as 0.00001 cm-1. Spectral data are most readily obtained by transmission (spectrophotometric) methods, using multiple internal reflection to increase effective sample length. Emissivity measurements, requiring extreme care in the elimination of detector noise and stray light, nevertheless afford the most accessible spectral data in the 0.0001 to 0.00001 cm-1 range. Single-wavelength informa-tion is most readily obtained with modifications of laser calorimetry. Thermo-couple detection of energy absorbed from a laser beam is convenient, but involves dc amplification techniques and is susceptible to stray-light problems. Photoacoustic detection, using ac methods, tends to diminish errors of these types, but at some expense in experimental complexity. Laser calorimetry has been used for measurements of absorption coefficients as small as 0.000003 cm-1. Both transmission and calorimetric data, taken as functions of intensity, have been used for measurement of nonlinear absorption coefficients.

  15. A novel solidified floating organic drop microextraction method for preconcentration and determination of copper ions by flow injection flame atomic absorption spectrometry in water samples

    Directory of Open Access Journals (Sweden)

    Arpa Şahin Ç.

    2013-04-01

    Full Text Available A simple, rapid and inexpensive solidified floating organic drop microextraction (SFODME and flow injection flame atomic absorption spectrometric determination (FI-FAAS method for copper was developed. 3-amino-7-dimethylamino-2-methylphenazine (Neutral red, NR was used as the complexing agent. Several factors affecting the microextraction efficiency, such as, pH, NR and sodium dodecylbenzenesulfonate (SDBS concentration, extraction time, stirring rate, and temperature were investigated and optimized. Under optimized experimental conditions an enrichment factor of 541 was obtained for 100 mL of sample solution. The calibration graph was linear in the range of 0.5 – 20.0 ng mL–1 and the limit of detection (3s was 0.18 ng mL–1, the limit of quantification (10s was 0.58 ng mL–1. The relative standard deviation (RSD for 10 replicate measurements of 10 ng mL–1 copper was 2.7%. The developed method was successfully applied to the extraction and determination of copper in different certified reference materials (Estuarine water, Slew 3 and fortified water, TM 23.2 and real water samples and satisfactory results were obtained.

  16. Mass spectrometric identification of isoforms of PR proteins in xylem sap of fungus-infected tomato

    NARCIS (Netherlands)

    Rep, Martijn; Dekker, Henk L.; Vossen, Jack H.; de Boer, Albert D.; Houterman, Petra M.; Speijer, Dave; Back, Jaap W.; de Koster, Chris G.; Cornelissen, Ben J. C.

    2002-01-01

    The protein content of tomato (Lycopersicon esculentum) xylem sap was found to change dramatically upon infection with the vascular wilt fungus Fusarium oxysporum. Peptide mass fingerprinting and mass spectrometric sequencing were used to identify the most abundant proteins appearing during

  17. Detection of ocean glint and ozone absorption using LCROSS Earth observations

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Tyler D. [NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035 (United States); Ennico, Kimberly [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Meadows, Victoria S.; Sparks, William; Schwieterman, Edward W. [NASA Astrobiology Institute' s Virtual Planetary Laboratory, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Bussey, D. Ben J. [NASA Ames Research Center, MS 17-1, Moffett Field, CA 94089, USA Now the NASA Solar System Exploration Research Virtual Institute. (United States); Breiner, Jonathan, E-mail: tyler.d.robinson@nasa.gov [Astronomy Department, University of Washington, Seattle, WA 98195 (United States)

    2014-06-01

    The Lunar CRater Observation and Sensing Satellite (LCROSS) observed the distant Earth on three occasions in 2009. These data span a range of phase angles, including a rare crescent phase view. For each epoch, the satellite acquired near-infrared and mid-infrared full-disk images, and partial-disk spectra at 0.26-0.65 μm (λ/Δλ ∼ 500) and 1.17-2.48 μm (λ/Δλ ∼ 50). Spectra show strong absorption features due to water vapor and ozone, which is a biosignature gas. We perform a significant recalibration of the UV-visible spectra and provide the first comparison of high-resolution visible Earth spectra to the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional spectral Earth model. We find good agreement with the observations, reproducing the absolute brightness and dynamic range at all wavelengths for all observation epochs, thus validating the model to within the ∼10% data calibration uncertainty. Data-model comparisons reveal a strong ocean glint signature in the crescent phase data set, which is well matched by our model predictions throughout the observed wavelength range. This provides the first observational test of a technique that could be used to determine exoplanet habitability from disk-integrated observations at visible and near-infrared wavelengths, where the glint signal is strongest. We examine the detection of the ozone 255 nm Hartley and 400-700 nm Chappuis bands. While the Hartley band is the strongest ozone feature in Earth's spectrum, false positives for its detection could exist. Finally, we discuss the implications of these findings for future exoplanet characterization missions.

  18. Detection of ocean glint and ozone absorption using LCROSS Earth observations

    International Nuclear Information System (INIS)

    Robinson, Tyler D.; Ennico, Kimberly; Meadows, Victoria S.; Sparks, William; Schwieterman, Edward W.; Bussey, D. Ben J.; Breiner, Jonathan

    2014-01-01

    The Lunar CRater Observation and Sensing Satellite (LCROSS) observed the distant Earth on three occasions in 2009. These data span a range of phase angles, including a rare crescent phase view. For each epoch, the satellite acquired near-infrared and mid-infrared full-disk images, and partial-disk spectra at 0.26-0.65 μm (λ/Δλ ∼ 500) and 1.17-2.48 μm (λ/Δλ ∼ 50). Spectra show strong absorption features due to water vapor and ozone, which is a biosignature gas. We perform a significant recalibration of the UV-visible spectra and provide the first comparison of high-resolution visible Earth spectra to the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional spectral Earth model. We find good agreement with the observations, reproducing the absolute brightness and dynamic range at all wavelengths for all observation epochs, thus validating the model to within the ∼10% data calibration uncertainty. Data-model comparisons reveal a strong ocean glint signature in the crescent phase data set, which is well matched by our model predictions throughout the observed wavelength range. This provides the first observational test of a technique that could be used to determine exoplanet habitability from disk-integrated observations at visible and near-infrared wavelengths, where the glint signal is strongest. We examine the detection of the ozone 255 nm Hartley and 400-700 nm Chappuis bands. While the Hartley band is the strongest ozone feature in Earth's spectrum, false positives for its detection could exist. Finally, we discuss the implications of these findings for future exoplanet characterization missions.

  19. Moessbauer spectrometric data acquisition based on FPGA

    International Nuclear Information System (INIS)

    Zhang Yuan; Li Shimin; Chen Nan; Zhu Jingbo; Xia Yuanfu

    2008-01-01

    FPGA(Field Programmable Gate Array) is a programmable device with strong logical function and timing control ability. It is extremely potent in acquiring and processing timing signals. By replacing the traditional used SCM (Single-Chip Microcomputer) with FPGA, counting speed of Moessbauer spectrometric data acquisition can be improved markedly with significantly decreased size of the spectrometer. The counter, RAM and RS-232 communication of the module are developed on Altera Cyclone series chip EP1C6T144C8 with Quartus II. EP1C6T144C8 has 5980 logical units accompanied by 92160 bits of memory space. It is so powerful that all needs in data acquisition of the Moessbauer spectrometer can be perfectly satisfied while allowing modifications in functions and parameters. (authors)

  20. 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

  1. Cloud point extraction and flame atomic absorption spectrometric determination of cadmium(II), lead(II), palladium(II) and silver(I) in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Ghaedi, Mehrorang, E-mail: m_ghaedi@mail.yu.ac.ir [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Shokrollahi, Ardeshir [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Niknam, Khodabakhsh [Chemistry Department, Persian Gulf University, Bushehr (Iran, Islamic Republic of); Niknam, Ebrahim; Najibi, Asma [Chemistry Department, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Soylak, Mustafa [Chemistry Department, University of Erciyes, 38039 Kayseri (Turkey)

    2009-09-15

    The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of cadmium(II), lead(II), palladium(II) and silver(I). The analytical procedure involved the formation of understudy metals complex with bis((1H-benzo [d] imidazol-2yl)ethyl) sulfane (BIES), and quantitatively extracted to the phase rich in octylphenoxypolyethoxyethanol (Triton X-114) after centrifugation. Methanol acidified with 1 mol L{sup -1} HNO{sub 3} was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The concentration of BIES, pH and amount of surfactant (Triton X-114) was optimized. At optimum conditions, the detection limits of (3 sdb/m) of 1.4, 2.8, 1.6 and 1.4 ng mL{sup -1} for Cd{sup 2+}, Pb{sup 2+}, Pd{sup 2+} and Ag{sup +} along with preconcentration factors of 30 and enrichment factors of 48, 39, 32 and 42 for Cd{sup 2+}, Pb{sup 2+}, Pd{sup 2+} and Ag{sup +}, respectively, were obtained. The proposed cloud point extraction has been successfully applied for the determination of metal ions in real samples with complicated matrix such as radiology waste, vegetable, blood and urine samples.

  2. Quantitative Detection of Singlet O2 by Cavity-Enhanced Absorption

    National Research Council Canada - National Science Library

    Williams, Skip; Gupta, Manish; Owano, Thomas; Baer, Douglas S; O'Keefe, Anthony; Yarkony, David R; Matsika, Spiridoula

    2004-01-01

    .... The method is based on sensitive off-axis integrated-cavity-output spectroscopy (ICOS). Off-axis ICOS allows narrowband, continuous-wave lasers to be used in conjunction with optical cavities to record sensitive absorption measurements...

  3. Mercury absorption in aqueous hypochlorite

    International Nuclear Information System (INIS)

    Zhao, L.L.; Rochelle, G.T.

    1999-01-01

    The absorption of elemental Hg vapor into aqueous hypochlorite was measured in a stirred tank reactor at 25 and 55C. NaOCl strongly absorbs Hg even at high pH. Low pH, high Cl - and high-temperature favor mercury absorption. Aqueous free Cl 2 was the active species that reacted with mercury. However, chlorine desorption was evident at high Cl - and pH 15 M -1 s -1 at 25C and 1.4x10 17 M -1 s -1 at 55C. Gas-phase reaction was observed between Hg and Cl 2 on apparatus surfaces. Strong mercury absorption in water was also detected with Cl 2 present. Results indicate that the chlorine concentration, moisture, and surface area contribute positively to mercury removal. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  4. Infrared absorption of CH3OSO detected with time-resolved Fourier-transform spectroscopy.

    Science.gov (United States)

    Chen, Jin-Dah; Lee, Yuan-Pern

    2011-03-07

    A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to detect temporally resolved infrared absorption spectra of CH(3)OSO produced upon irradiation of a flowing gaseous mixture of CH(3)OS(O)Cl in N(2) or CO(2) at 248 nm. Two intense transient features with origins near 1152 and 994 cm(-1) are assigned to syn-CH(3)OSO; the former is attributed to overlapping bands at 1154 ± 3 and 1151 ± 3 cm(-1), assigned to the S=O stretching mixed with CH(3) rocking (ν(8)) and the S=O stretching mixed with CH(3) wagging (ν(9)) modes, respectively, and the latter to the C-O stretching (ν(10)) mode at 994 ± 6 cm(-1). Two weak bands at 2991 ± 6 and 2956 ± 3 cm(-1) are assigned as the CH(3) antisymmetric stretching (ν(2)) and symmetric stretching (ν(3)) modes, respectively. Observed vibrational transition wavenumbers agree satisfactorily with those predicted with quantum-chemical calculations at level B3P86∕aug-cc-pVTZ. Based on rotational parameters predicted at that level, the simulated rotational contours of these bands agree satisfactorily with experimental results. The simulation indicates that the S=O stretching mode of anti-CH(3)OSO near 1164 cm(-1) likely makes a small contribution to the observed band near 1152 cm(-1). A simple kinetic model of self-reaction is employed to account for the decay of CH(3)OSO and yields a second-order rate coefficient k=(4 ± 2)×10(-10) cm(3)molecule(-1)s(-1). © 2011 American Institute of Physics.

  5. Mid-IR absorption sensing of heavy water using a silicon-on-sapphire waveguide.

    Science.gov (United States)

    Singh, Neetesh; Casas-Bedoya, Alvaro; Hudson, Darren D; Read, Andrew; Mägi, Eric; Eggleton, Benjamin J

    2016-12-15

    We demonstrate a compact silicon-on-sapphire (SOS) strip waveguide sensor for mid-IR absorption spectroscopy. This device can be used for gas and liquid sensing, especially to detect chemically similar molecules and precisely characterize extremely absorptive liquids that are difficult to detect by conventional infrared transmission techniques. We reliably measure concentrations up to 0.25% of heavy water (D2O) in a D2O-H2O mixture at its maximum absorption band at around 4 μm. This complementary metal-oxide-semiconductor (CMOS) compatible SOS D2O sensor is promising for applications such as measuring body fat content or detection of coolant leakage in nuclear reactors.

  6. Nuclear resonance absorption (NRA): method and application to detection of contraband in a baggage, cargo and vehicles

    International Nuclear Information System (INIS)

    Goldenberg, M.B.; Vartsky, D.; Engler, G.

    1996-01-01

    Nuclear Resonance Absorption (NRA) has played a prominent role in nuclear spectroscopy for almost 5 decades, but found only few and marginal applications outside the laboratory before 1985. In that year the situation changed markedly when scientists from this laboratory proposed to the Federal Aviation Administration (FAA) in the U.S. to study its suitability for detecting explosives in passenger baggage via nitrogen-specific radiographic imaging (explosives, as a category, have inordinately high nitrogen densities). Following a basic feasibility study and the first laboratory demonstration of explosives detection in 1989, this project has attained the stage of a pre-industrial prototype that exhibited excellent performance characteristics in a 1993 blind test conducted by the FAA. In terms of NRA operational system concept, data taking methodology, development of dedicated detectors and image analysis algorithms, the Soreq group has made a major, if not exclusive, contribution over the years. (authors)

  7. Impact of solvent conditions on separation and detection of basic drugs by micro liquid chromatography-mass spectrometry under overloading conditions.

    Science.gov (United States)

    Schubert, Birthe; Oberacher, Herbert

    2011-06-03

    In this study the impact of solvent conditions on the performance of μLC/MS for the analysis of basic drugs was investigated. Our aim was to find experimental conditions that enable high-performance chromatographic separation particularly at overloading conditions paired with a minimal loss of mass spectrometric detection sensitivity. A focus was put on the evaluation of the usability of different kinds of acidic modifiers (acetic acid (HOAc), formic acid (FA), methansulfonic acid (CH₃SO₃H), trifluoroacetic acid (TFA), pentafluoropropionic acid (PFPA), and heptafluorobutyric acid (HFBA)). The test mixture consisted of eleven compounds (bunitrolol, caffeine, cocaine, codeine, diazepam, doxepin, haloperidol, 3,4-methylendioxyamphetamine, morphine, nicotine, and zolpidem). Best chromatographic performance was obtained with the perfluorinated acids. Particularly, 0.010-0.050% HFBA (v/v) was found to represent a good compromise in terms of chromatographic performance and mass spectrometric detection sensitivity. Compared to HOAc, on average a 50% reduction of the peak widths was observed. The use of HFBA was particularly advantageous for polar compounds such as nicotine; only with such a hydrophobic ion-pairing reagent chromatographic retention of nicotine was observed. Best mass spectrometric performance was obtained with HOAc and FA. Loss of detection sensitivity induced by HFBA, however, was moderate and ranged from 0 to 40%, which clearly demonstrates that improved chromatographic performance is able to compensate to a large extent the negative effect of reduced ionization efficiency on detection sensitivity. Applications of μLC/MS for the qualitative and quantitative analysis of clinical and forensic toxicological samples are presented. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Establishment of limits of detection and decision

    International Nuclear Information System (INIS)

    Mende, O.; Michel, R.

    1995-01-01

    The purpose of this project was to develop and test procedures to establish limits of decision and detection for spectrometric nuclear radiation measurements. Beside the determination of the limits of application of DIN 25482 part 2 and 5 - both primarily suitable for high resoluted spectra areas -the statistical model was expanded in such a way that henceforth blanks and influences of sample treatment can also be taken into account; the corresponding procedures to calculate the limits of decision and detection have a high precision. Additional procedures of calculation were developed to take the special characteristics of the analysis of complex spectra areas into account. (orig.) [de

  9. Development, validation and application of an ultra high performance liquid chromatographic-tandem mass spectrometric method for the simultaneous detection and quantification of five different classes of veterinary antibiotics in swine manure.

    Science.gov (United States)

    Van den Meersche, Tina; Van Pamel, Els; Van Poucke, Christof; Herman, Lieve; Heyndrickx, Marc; Rasschaert, Geertrui; Daeseleire, Els

    2016-01-15

    In this study, a fast, simple and selective ultra high performance liquid chromatographic-tandem mass spectrometric (UHPLC-MS/MS) method for the simultaneous detection and quantification of colistin, sulfadiazine, trimethoprim, doxycycline, oxytetracycline and ceftiofur and for the detection of tylosin A in swine manure was developed and validated. First, a simple extraction procedure with acetonitrile and 6% trichloroacetic acid was carried out. Second, the supernatant was evaporated and the pellet was reconstituted in 1 ml of water/acetonitrile (80/20) and 0.1% formic acid. Extracts were filtered and analyzed by UHPLC-MS/MS on a Kinetex C18 column using gradient elution. The method developed was validated according to the criteria of Commission Decision 2002/657/EC. Recovery percentages varied between 94% and 106%, repeatability percentages were within the range of 1.7-9.2% and the intralaboratory reproducibility varied between 2.8% and 9.3% for all compounds, except for tylosin A for which more variation was observed resulting in a higher measurement uncertainty. The limit of detection and limit of quantification varied between 1.1 and 20.2 and between 3.5 and 67.3 μg/kg, respectively. This method was used to determine the presence and concentration of the seven antibiotic residues in swine manure sampled from ten different manure pits on farms where the selected antibiotics were used. A link was found between the antibiotics used and detected, except for ceftiofur which is injected at low doses and degraded readily in swine manure and was therefore not recovered in any of the samples. To the best of our knowledge, this is the first method available for the simultaneous extraction and quantification of colistin with other antibiotic classes. Additionally, colistin was never extracted from swine manure before. Another innovative aspect of this method is the simultaneous detection and quantification of five different classes of antibiotic residues in swine manure

  10. Mass spectrometric study of Nd2S3 vaporization

    International Nuclear Information System (INIS)

    Fenochka, B.V.

    1987-01-01

    The authors conduct a mass-spectrometric study of neodymium(III) sulfide vaporization. The chemical composition of the samples was stoichiometric and the samples were vaporized from tantalum effusion cells. When the vapor over Nd 2 S 3 is ionized by electrons the mass spectra shows monovalent cations of Nd, S, NdS, and NdO. The enthalpy of vaporization if Nd atoms from Nd 2 S 3 at average experimental temperatures and the standard enthalpy of reaction is shown. Also presented is the enthalpy of vaporization of NdS molecules from Nd 2 S 3 at average experimental temperatures and the standard enthalpy of reaction

  11. New sensitive high-performance liquid chromatography-tandem mass spectrometry method for the detection of horse and pork in halal beef.

    Science.gov (United States)

    von Bargen, Christoph; Dojahn, Jörg; Waidelich, Dietmar; Humpf, Hans-Ulrich; Brockmeyer, Jens

    2013-12-11

    The accidental or fraudulent blending of meat from different species is a highly relevant aspect for food product quality control, especially for consumers with ethical concerns against species, such as horse or pork. In this study, we present a sensitive mass spectrometrical approach for the detection of trace contaminations of horse meat and pork and demonstrate the specificity of the identified biomarker peptides against chicken, lamb, and beef. Biomarker peptides were identified by a shotgun proteomic approach using tryptic digests of protein extracts and were verified by the analysis of 21 different meat samples from the 5 species included in this study. For the most sensitive peptides, a multiple reaction monitoring (MRM) method was developed that allows for the detection of 0.55% horse or pork in a beef matrix. To enhance sensitivity, we applied MRM(3) experiments and were able to detect down to 0.13% pork contamination in beef. To the best of our knowledge, we present here the first rapid and sensitive mass spectrometrical method for the detection of horse and pork by use of MRM and MRM(3).

  12. On the Origin of Microheterogeneity : A Mass Spectrometric Study of Dimethyl Sulfoxide-Water Binary Mixture

    NARCIS (Netherlands)

    Shin, Dong Nam; Wijnen, Jan W.; Engberts, Jan B.F.N.; Wakisaka, Akihiro

    2001-01-01

    We have studied the microscopic solvent structure of dimethyl sulfoxide-water mixtures and its influence on the solvation structure of solute from a clustering point of View, by means of a specially designed mass spectrometric system. It was observed that the propensity to the cluster formation is

  13. Absorption-line detections of 105-106 K gas in spiral-rich groups of galaxies

    International Nuclear Information System (INIS)

    Stocke, John T.; Keeney, Brian A.; Danforth, Charles W.; Syphers, David; Yamamoto, H.; Shull, J. Michael; Green, James C.; Froning, Cynthia; Savage, Blair D.; Wakker, Bart; Kim, Tae-Sun; Ryan-Weber, Emma V.; Kacprzak, Glenn G.

    2014-01-01

    Using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, the COS Science Team has conducted a high signal-to-noise survey of 14 bright QSOs. In a previous paper, these far-UV spectra were used to discover 14 'warm' (T ≥ 10 5 K) absorbers using a combination of broad Lyα and broad O VI absorptions. A reanalysis of a few of this new class of absorbers using slightly relaxed fitting criteria finds as many as 20 warm absorbers could be present in this sample. A shallow, wide spectroscopic galaxy redshift survey has been conducted around these sight lines to investigate the warm absorber environment, which is found to be spiral-rich groups or cluster outskirts with radial velocity dispersions σ = 250-750 km s –1 . While 2σ evidence is presented favoring the hypothesis that these absorptions are associated with the galaxy groups and not with the individual, nearest galaxies, this evidence has considerable systematic uncertainties and is based on a small sample size so it is not entirely conclusive. If the associations are with galaxy groups, the observed frequency of warm absorbers (dN/dz = 3.5-5 per unit redshift) requires them to be very extended as an ensemble on the sky (∼1 Mpc in radius at high covering factor). Most likely these warm absorbers are interface gas clouds whose presence implies the existence of a hotter (T ∼ 10 6.5 K), diffuse, and probably very massive (>10 11 M ☉ ) intra-group medium which has yet to be detected directly.

  14. Capillary isotachophoresis with ESI-MS detection: Methodology for highly sensitive analysis of ibuprofen and diclofenac in waters

    Czech Academy of Sciences Publication Activity Database

    Malá, Zdeňka; Gebauer, Petr; Boček, Petr

    2016-01-01

    Roč. 907, FEB (2016), s. 1-6 ISSN 0003-2670 R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : isotachophoresis * mass spectrometric detection * Diclofenac * Ibuprofen Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.950, year: 2016

  15. Magnetic dispersive solid-phase extraction based on graphene oxide/Fe3 O4 @polythionine nanocomposite followed by atomic absorption spectrometry for zinc monitoring in water, flour, celery and egg.

    Science.gov (United States)

    Babaei, Azar; Zeeb, Mohsen; Es-Haghi, Ali

    2018-07-01

    Magnetic graphene oxide nanocomposite has been proposed as a promising and sustainable sorbent for the extraction and separation of target analytes from food matrices. Sample preparation based on nanocomposite presents several advantages, such as desired efficiency, reasonable selectivity and high surface-area-to-volume ratio. A new graphene oxide/Fe 3 O 4 @polythionine (GO/Fe 3 O 4 @PTh) nanocomposite sorbent was introduced for magnetic dispersive solid-phase extraction and flame atomic absorption spectrometric detection of zinc(II) in water, flour, celery and egg. To fabricate the sorbent, an oxidative polymerization of thionine on the surface of magnetic GO was applied, while polythionine was simply employed as a surface modifier to improve extraction yield. The properties of the sorbent were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis, vibrating sample magnetometry and Fourier transform-infrared spectroscopy. The calibration curve showed linearity in the range of 0.5-30 ng mL -1 . Limits of detection (S/N = 3) and quantification (S/N = 10) were 0.08 and 0.5 ng mL -1 , respectively. The method was applied for trace-level determination of Zn(II) in water and food samples, and its validation was investigated by recovery experiments and analyzing certified reference material. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  16. A new ultrasonic-assisted cloud-point-extraction procedure for pre-concentration and determination of ultra-trace levels of copper in selected beverages and foods by flame atomic absorption spectrometry.

    Science.gov (United States)

    Altunay, Nail; Gürkan, Ramazan; Orhan, Ulaş

    2015-01-01

    A new ultrasonic-assisted cloud-point-extraction (UA-CPE) method was developed for the pre-concentration of Cu(II) in selected beverage and food samples prior to flame atomic absorption spectrometric (FAAS) analysis. For this purpose, Safranin T was used as an ion-pairing reagent based on charge transfer in the presence of oxalate as the primary chelating agent at pH 10. Non-ionic surfactant, poly(ethyleneglycol-mono-p-nonylphenylether) (PONPE 7.5) was used as an extracting agent in the presence of NH4Cl as the salting out agent. The variables affecting UA-CPE efficiency were optimised in detail. The linear range for Cu(II) at pH 10 was 0.02-70 µg l(-)(1) with a very low detection limit of 6.10 ng l(-)(1), while the linear range for Cu(I) at pH 8.5 was 0.08-125 µg l(-)(1) with a detection limit of 24.4 ng l(-)(1). The relative standard deviation (RSD %) was in the range of 2.15-4.80% (n = 5). The method was successfully applied to the quantification of Cu(II), Cu(I) and total Cu in selected beverage and food samples. The accuracy of the developed method was demonstrated by the analysis of two standard reference materials (SRMs) as well as recoveries of spiked samples.

  17. 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.)

  18. GREEN BANK TELESCOPE DETECTION OF POLARIZATION-DEPENDENT H I ABSORPTION AND H I OUTFLOWS IN LOCAL ULIRGs AND QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Stacy H. [Observational Cosmology Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Veilleux, Sylvain [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Baker, Andrew J., E-mail: stacy.h.teng@nasa.gov [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States)

    2013-03-10

    We present the results of a 21 cm H I survey of 27 local massive gas-rich late-stage mergers and merger remnants with the Robert C. Byrd Green Bank Telescope. These remnants were selected from the Quasar/ULIRG Evolution Study sample of ultraluminous infrared galaxies (ULIRGs; L{sub 8{sub -{sub 1000{sub {mu}m}}}} > 10{sup 12} L{sub Sun }) and quasars; our targets are all bolometrically dominated by active galactic nuclei (AGNs) and sample the later phases of the proposed ULIRG-to-quasar evolutionary sequence. We find the prevalence of H I absorption (emission) to be 100% (29%) in ULIRGs with H I detections, 100% (88%) in FIR-strong quasars, and 63% (100%) in FIR-weak quasars. The absorption features are associated with powerful neutral outflows that change from being mainly driven by star formation in ULIRGs to being driven by the AGN in the quasars. These outflows have velocities that exceed 1500 km s{sup -1} in some cases. Unexpectedly, we find polarization-dependent H I absorption in 57% of our spectra (88% and 63% of the FIR-strong and FIR-weak quasars, respectively). We attribute this result to absorption of polarized continuum emission from these sources by foreground H I clouds. About 60% of the quasars displaying polarized spectra are radio-loud, far higher than the {approx}10% observed in the general AGN population. This discrepancy suggests that radio jets play an important role in shaping the environments in these galaxies. These systems may represent a transition phase in the evolution of gas-rich mergers into ''mature'' radio galaxies.

  19. Agnostic stacking of intergalactic doublet absorption: measuring the Ne VIII population

    Science.gov (United States)

    Frank, Stephan; Pieri, Matthew M.; Mathur, Smita; Danforth, Charles W.; Shull, J. Michael

    2018-05-01

    We present a blind search for doublet intergalactic metal absorption with a method dubbed `agnostic stacking'. Using a forward-modelling framework, we combine this with direct detections in the literature to measure the overall metal population. We apply this novel approach to the search for Ne VIII absorption in a set of 26 high-quality COS spectra. We probe to an unprecedented low limit of log N>12.3 at 0.47≤z ≤1.34 over a path-length Δz = 7.36. This method selects apparent absorption without requiring knowledge of its source. Stacking this mixed population dilutes doublet features in composite spectra in a deterministic manner, allowing us to measure the proportion corresponding to Ne VIII absorption. We stack potential Ne VIII absorption in two regimes: absorption too weak to be significant in direct line studies (12.3 13.7). We do not detect Ne VIII absorption in either regime. Combining our measurements with direct detections, we find that the Ne VIII population is reproduced with a power-law column density distribution function with slope β = -1.86 ^{+0.18 }_{ -0.26} and normalization log f_{13.7} = -13.99 ^{+0.20 }_{ -0.23}, leading to an incidence rate of strong Ne VIII absorbers dn/dz =1.38 ^{+0.97 }_{ -0.82}. We infer a cosmic mass density for Ne VIII gas with 12.3 value significantly lower that than predicted by recent simulations. We translate this density into an estimate of the baryon density Ωb ≈ 1.8 × 10-3, constituting 4 per cent of the total baryonic mass.

  20. Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

    Science.gov (United States)

    Korecki, P.; Tolkiehn, M.; Dąbrowski, K. M.; Novikov, D. V.

    2011-01-01

    Projections of the atomic structure around Nb atoms in a LiNbO3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples. PMID:21997909

  1. In situ gamma-ray spectrometric analysis of radionuclide distributions at a commercial shallow land burial site

    International Nuclear Information System (INIS)

    Kirby, L.J.; Campbell, R.M.

    1984-10-01

    Gamma-ray spectrometric analysis conducted at the Maxey Flats, Kentucky (USA) shallow land burial site confirmed that the waste radionuclides have been retained largely within the restricted area of the burial site. Concentrations of 137 Cs and 60 Co were comparable with those originating from global fallout and lower than concentrations measured in several other areas having similar rainfall. In-situ spectrometric analyses, corroborated by soil sample and vegetation analyses, indicate that the site has influenced 60 Co levels slightly in the west drainage channel, but 137 Cs did not originate from the site. Concentrations of 60 Co, 90 Sr and 137 Cs determined in subsurface soils by well logging techniques confirmed that subsurface migration of waste-derived radionuclides to points outside the restricted area has not been a significant source of contamination of the environs adjacent to the site. 8 references, 8 figures

  2. Challenges and recent advances in mass spectrometric imaging of neurotransmitters

    Science.gov (United States)

    Gemperline, Erin; Chen, Bingming; Li, Lingjun

    2014-01-01

    Mass spectrometric imaging (MSI) is a powerful tool that grants the ability to investigate a broad mass range of molecules, from small molecules to large proteins, by creating detailed distribution maps of selected compounds. To date, MSI has demonstrated its versatility in the study of neurotransmitters and neuropeptides of different classes toward investigation of neurobiological functions and diseases. These studies have provided significant insight in neurobiology over the years and current technical advances are facilitating further improvements in this field. neurotransmitters, focusing specifically on the challenges and recent Herein, we advances of MSI of neurotransmitters. PMID:24568355

  3. Mass Spectrometric Analysis of Synthetic Organic Pigments.

    Science.gov (United States)

    Sugaya, Naeko; Takahashi, Mitsuko; Sakurai, Katsumi; Tanaka, Nobuko; Okubo, Ichiro; Kawakami, Tsuyoshi

    2018-04-18

    Though synthetic organic colorants are used in various applications nowadays, there is the concern that impurities by-produced during the manufacturing and degradation products in some of these colorants are persistent organic pollutants and carcinogens. Thus, it is important to identify the synthetic organic colorants in various products, such as commercial paints, ink, cosmetics, food, textile, and plastics. Dyes, which are soluble in water and other solvents, could be analyzed by chromatographic methods. In contrast, it is difficult to analyze synthetic organic pigments by these methods because of their insolubility. This review is an overview of mass spectrometric analysis of synthetic organic pigments by various ionization methods. We highlight a recent study of textile samples by atmospheric pressure solid analysis probe MS. Furthermore, the mass spectral features of synthetic organic pigments and their separation from other components such as paint media and plasticizers are discussed.

  4. Determination of trace metal ions via on-line separation and preconcentration by means of chelating Sepharose beads in a sequential injection lab-on-valve (SI-LOV) system coupled to electrothermal atomic absorption spectrometric detection

    DEFF Research Database (Denmark)

    Long, Xiangbao; Hansen, Elo Harald; Miró, Manuel

    2005-01-01

    The analytical performance of an on-line sequential injection lab-on-valve (SI-LOV) system using chelating Sepharose beads as sorbent material for the determination of ultra trace levels of Cd(II), Pb(II) and Ni(II) by electrothermal atomic absorption spectrometry (ETAAS) is described and discussed...

  5. Maintenance of stability in γ spectrometric system of low active and environmental samples - a practical experience

    International Nuclear Information System (INIS)

    Ravishankar, R.; Bandyopadhyay, T.; Sarkar, P.K.

    2011-01-01

    Particle Accelerators are becoming part of the society with more and more medical and Industrial types are added every year in addition to research type of accelerators. The outflow of materials to the public domain from such accelerator facilities need to checked carefully and must be released after ensuring the activities of such materials should not exceed the regulatory limits. Health Physics Unit, VECC is involved in analyzing food product samples, seized samples which are suspected to contain Uranium etc and other environmental samples in addition to analyzing radioactive materials evolved from Operational Health Physics work. Most of these analyses involve γ Spectrometric Systems of high efficiency and high resolution types. The efficacy of the analysis and results depends on various parameters of the spectrometric system. The electrical noise from the power supply system and other noises picked up, even in the range of a few milli volts range, have been found to affect the stability of the system. These effects may not be present initially during installation but may creep in due course due to various reasons including weather conditions, wear and tear etc. Unless these problems are attended in regular intervals, the stability of the spectrometric systems and hence the results of analysis of the low active and environmental samples, will not be satisfactory. The work describes the practical problems faced by Health Physics Unit, the methods employed in identifying the problems, the necessary remedial measures taken, the final outcome in the stability and the procedures framed in order to avoid in future. (author)

  6. Emission and absorption of radiation

    International Nuclear Information System (INIS)

    Fetter, S.

    1992-01-01

    A full understanding of fissile-material detection requires a solid knowledge of nuclear physics, especially the emission and absorption of radiation. The purpose of this paper is therefore to give a brief explanation of these processes so that the reader can better understand the assumptions leading to the results in the main text

  7. Nucleon multiplicities after pion absorption in 160

    International Nuclear Information System (INIS)

    Hamers, R.

    1989-01-01

    The experiment described in this thesis concerns a simultaneous measurement of two- and higher-fold coincidences following positive and negative pion absorption in 16 0. The detected particles are protons, neutrons and deuterons. The detection and analysis of charged particles is discussed. The incident pion energy was 65 MeV, thus well below the delta resonance. The low pion energy was 65 MeV, thus well below the delta resonance. The low pion energy ensures that contributions of initial state interactions, i.e. pion-nucleon scattering preceding absorption, are minimized. The following reaction channels were selected and analyzed: π + ,pp), (π + ,pd). Evidence for quasifree reaction precessed has been investigated by comparing the data with phase-space calculations incorporating the geometry of the experimental setup. (author). 36 refs.; 1 figs.; 3 tabs

  8. Modern spectrometric methods for the analysis of labelled compounds

    International Nuclear Information System (INIS)

    Kaspersen, F.M.; Funke, C.W.; Wagenaars, G.N.; Jacobs, P.L.

    1988-01-01

    A proper analysis of chemical compounds should give information about the chemical identity (not only the structure but also enantiomeric form), the chemical purity and chemical composition (e.g. giving information about counter-ions, solvents of crystallization). For labelled compounds information is also needed about isotopic purity (defined as the % of isotope present in the compound), the position/distribution of the isotope in the molecule and degree of labelling/specific activity. In the past ten years the possibilities for spectrometric analyses of labelled compounds have increased enormously and this chapter will give an overview of these methods with the exception of (radio)chromatography that will be dealt with in another chapter. (author)

  9. Gamma-spectrometric surveys in differentiated granites. I: a review of the method and of the geochemical behavior of K, Th and U; Levantamentos gamaespectrometricos em granitos diferenciados. I: revisao da metodologia e do comportamento geoquimico dos elementos K, Th e U

    Energy Technology Data Exchange (ETDEWEB)

    Ulbrich, Horstpeter Herberto Gustavo Jose; Ulbrich, Mabel Norma Costas [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias. Dept. de Mineralogia e Geotectonica], e-mail: hulbrich@usp.br, e-mail: mulbrich@usp.br; Ferreira, Francisco Jose Fonseca [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Geologia. Lab. de Pesquisas em Geofisica Aplicada; Alves, Luizemara Soares [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)], e-mail: luizemara@petrobras.com.br; Guimaraes, Gilson Burigo [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Dept. de Geociencias], e-mail: gburigo@ig.com.br; Fruchting, Allan [Votorantim Metais, Sao Paulo, SP (Brazil)], e-mail: allan.fruchting@vmetais.com.br

    2009-07-01

    This contribution is part of a research project on the Neo proterozoic Cunhaporanga Granitic Complex (CGC), cropping out in the Ponta Grossa Arch (Parana state, SE Brazil). An initial study used the gamma-spectrometric data of the Serra do Mar Sul Aero geophysical Project, performed during the 70's for CPRM. Later, terrestrial gamma-spectrometric surveys focused on the study of the differentiated Joaquim Murtinho Granite (JMG) in the NW corner of CGC, and the Serra do Carambei Granite, to the SW. In this paper, the results obtained for JMG are presented in two parts. The first deals with methodology and the presentation of several gamma-spectrometric 'color-scale' maps, indicating that results obtained in granites depend strongly on a climatic factor, given the mobility of K during weathering in subtropical climates with strong rainfalls, also favoring a greater mobility of U. Minerals that are U and Th hosts, documented in granites, are reviewed, together with the weathering processes that control the mobility of K, U and Th in soils. Strong K signals in granitic areas submitted to these climates document the presence of fresh rock and/or effects of hydrothermal alteration, while weak or nil signals are evidence of strong leaching of K during weathering. U and Th will be retained in the residual soils, in part leading to their selective enrichment, also coupled with soil migration to lower topographic levels by colluvial transport. The larger solubility of U (as uranyl ion) allows its liberation under oxidizing conditions, and its migration, limited by the possibility of absorption in newly formed mineral and organic soil phases. Th should be retained almost totally in resistant phases and, when liberated in solution, will mostly be fixed in organic and inorganic soil substances. (author)

  10. Absorption by Spinning Dust: A Contaminant for High-redshift 21 cm Observations

    Science.gov (United States)

    Draine, B. T.; Miralda-Escudé, Jordi

    2018-05-01

    Spinning dust grains in front of the bright Galactic synchrotron background can produce a weak absorption signal that could affect measurements of high-redshift 21 cm absorption. At frequencies near 80 MHz where the Experiment to Detect the Global EoR Signature (EDGES) has reported 21 cm absorption at z≈ 17, absorption could be produced by interstellar nanoparticles with radii a≈ 50 \\mathringA in the cold interstellar medium (ISM), with rotational temperature T ≈ 50 K. Atmospheric aerosols could contribute additional absorption. The strength of the absorption depends on the abundance of such grains and on their dipole moments, which are uncertain. The breadth of the absorption spectrum of spinning dust limits its possible impact on measurement of a relatively narrow 21 cm absorption feature.

  11. in local and foreign brands of lipsticks in fct, abuja, nigeria 318

    African Journals Online (AJOL)

    userpc

    This study determined toxic heavy metal concentration in Local and Foreign brands of lipsticks sold in FCT ... (10) Local and ten (10) Foreign brands for Lead using flame atomic absorption .... study, Flame Atomic Absorption Spectrometric.

  12. Vapor generation – atomic spectrometric techniques. Expanding frontiers through specific-species preconcentration. A review

    International Nuclear Information System (INIS)

    Gil, Raúl A.; Pacheco, Pablo H.; Cerutti, Soledad; Martinez, Luis D.

    2015-01-01

    This article reviews 120 articles found in SCOPUS and specific Journal cites corresponding to the terms ‘preconcentration’; ‘speciation’; ‘vapor generation techniques’ and ‘atomic spectrometry techniques’ in the last 5 years. - Highlights: • Recent advances in vapor generation and atomic spectrometry were reviewed. • Species-specific preconcentration strategies after and before VG were discussed. • New preconcentration and speciation analysis were evaluated within this framework. - Abstract: We review recent progress in preconcentration strategies associated to vapor generation techniques coupled to atomic spectrometric (VGT-AS) for specific chemical species detection. This discussion focuses on the central role of different preconcentration approaches, both before and after VG process. The former was based on the classical solid phase and liquid–liquid extraction procedures which, aided by automation and miniaturization strategies, have strengthened the role of VGT-AS in several research fields including environmental, clinical, and others. We then examine some of the new vapor trapping strategies (atom-trapping, hydride trapping, cryotrapping) that entail improvements in selectivity through interference elimination, but also they allow reaching ultra-low detection limits for a large number of chemical species generated in conventional VG systems, including complete separation of several species of the same element. This review covers more than 100 bibliographic references from 2009 up to date, found in SCOPUS database and in individual searches in specific journals. We finally conclude by giving some outlook on future directions of this field

  13. Vapor generation – atomic spectrometric techniques. Expanding frontiers through specific-species preconcentration. A review

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Raúl A.; Pacheco, Pablo H.; Cerutti, Soledad [Área de Química Analítica, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina); Instituto de Química de San Luis, INQUISAL, Centro Científico-Tecnológico de San Luis (CCT-San Luis), Consejo Nacional de Investigaciones Científicas y Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina); Martinez, Luis D., E-mail: ldm@unsl.edu.ar [Área de Química Analítica, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina); Instituto de Química de San Luis, INQUISAL, Centro Científico-Tecnológico de San Luis (CCT-San Luis), Consejo Nacional de Investigaciones Científicas y Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina)

    2015-05-22

    This article reviews 120 articles found in SCOPUS and specific Journal cites corresponding to the terms ‘preconcentration’; ‘speciation’; ‘vapor generation techniques’ and ‘atomic spectrometry techniques’ in the last 5 years. - Highlights: • Recent advances in vapor generation and atomic spectrometry were reviewed. • Species-specific preconcentration strategies after and before VG were discussed. • New preconcentration and speciation analysis were evaluated within this framework. - Abstract: We review recent progress in preconcentration strategies associated to vapor generation techniques coupled to atomic spectrometric (VGT-AS) for specific chemical species detection. This discussion focuses on the central role of different preconcentration approaches, both before and after VG process. The former was based on the classical solid phase and liquid–liquid extraction procedures which, aided by automation and miniaturization strategies, have strengthened the role of VGT-AS in several research fields including environmental, clinical, and others. We then examine some of the new vapor trapping strategies (atom-trapping, hydride trapping, cryotrapping) that entail improvements in selectivity through interference elimination, but also they allow reaching ultra-low detection limits for a large number of chemical species generated in conventional VG systems, including complete separation of several species of the same element. This review covers more than 100 bibliographic references from 2009 up to date, found in SCOPUS database and in individual searches in specific journals. We finally conclude by giving some outlook on future directions of this field.

  14. Self-absorption and self-scattering in emitter source of alpha particles

    International Nuclear Information System (INIS)

    Terini, R.A.

    1990-01-01

    This paper describes preliminary results on spectrometric analysis and activity measurements of alpha-emitting sources prepared by evaporation on mylar. The measurements were made with a Si surface barrier detector. By the analysis of the angular distribuition of the alpha particles emitted, it was possible to observe that the width of the spectrum low energy tail increases with the emission angle θ, due to the energy degradation in the source material, which affects the measured particles energy. The source activity was also measured from detection solid angles of approx. 10 -1 and aprox. 10 -3 Sr, as a function of θ. The absolute activity of the alpha source was determined and a discussion is present on the ideal conditions necessary for such measurements. (author) [pt

  15. Thomson Thick X-Ray Absorption in a Broad Absorption Line Quasar, PG 0946+301.

    Science.gov (United States)

    Mathur; Green; Arav; Brotherton; Crenshaw; deKool; Elvis; Goodrich; Hamann; Hines; Kashyap; Korista; Peterson; Shields; Shlosman; van Breugel W; Voit

    2000-04-20

    We present a deep ASCA observation of a broad absorption line quasar (BALQSO) PG 0946+301. The source was clearly detected in one of the gas imaging spectrometers, but not in any other detector. If BALQSOs have intrinsic X-ray spectra similar to normal radio-quiet quasars, our observations imply that there is Thomson thick X-ray absorption (NH greater, similar1024 cm-2) toward PG 0946+301. This is the largest column density estimated so far toward a BALQSO. The absorber must be at least partially ionized and may be responsible for attenuation in the optical and UV. If the Thomson optical depth toward BALQSOs is close to 1, as inferred here, then spectroscopy in hard X-rays with large telescopes like XMM would be feasible.

  16. Backscatter absorption gas imaging systems and light sources therefore

    Science.gov (United States)

    Kulp, Thomas Jan [Livermore, CA; Kliner, Dahv A. V. [San Ramon, CA; Sommers, Ricky [Oakley, CA; Goers, Uta-Barbara [Campbell, NY; Armstrong, Karla M [Livermore, CA

    2006-12-19

    The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorption gas imaging (BAGI) system, and a light source incorporating the light source, that can be used to remotely detect and produce images of "invisible" gases. The inventive light source has a light producing element, an optical amplifier, and an optical parametric oscillator to generate wavelength tunable light in the IR. By using a multi-mode light source and an amplifier that operates using 915 nm pump sources, the power consumption of the light source is reduced to a level that can be operated by batteries for long periods of time. In addition, the light source is tunable over the absorption bands of many hydrocarbons, making it useful for detecting hazardous gases.

  17. Onward treatment of irradiated liquid egg: Detection in sponge cake mixture after baking by means of LC-GC-MS

    International Nuclear Information System (INIS)

    Grabowski, H.U. von; Schulzki, G.; Pfordt, J.; Spiegelberg, A.; Helle, N.; Boegl, K.W.; Schreiber, G.A.

    1993-01-01

    Irradiated whole liquid egg used for preparation of sponge cake could be identified using gaschromatographic/mass spectrometric detection of the radiation induced hydrocarbons for doses from 1 kGy. Separation of the hydrocarbons out of the fat was carried out by HPLC coupled on-line to the GC. That means, for the first time an irradiated component of a heat treated food could be detected. (orig.) [de

  18. Liquid chromatography/mass spectrometric determination of patulin in apple juice using atmospheric pressure photoionization.

    Science.gov (United States)

    Takino, Masahiko; Daishima, Shigeki; Nakahara, Taketoshi

    2003-01-01

    This paper describes a comparison between atmospheric pressure chemical ionization (APCI) and the recently introduced atmospheric pressure photoionization (APPI) technique for the liquid chromatography/mass spectrometric (LC/MS) determination of patulin in clear apple juice. A column switching technique for on-line extraction of clear apple juice was developed. The parameters investigated for the optimization of APPI were the ion source parameters fragmentor voltage, capillary voltage, and vaporizer temperature, and also mobile phase composition and flow rate. Furthermore, chemical noise and signal suppression of analyte signals due to sample matrix interference were investigated for both APCI and APPI. The results indicated that APPI provides lower chemical noise and signal suppression in comparison with APCI. The linear range for patulin in apple juice (correlation coefficient >0.999) was 0.2-100 ng mL(-1). Mean recoveries of patulin in three apple juices ranged from 94.5 to 103.2%, and the limit of detection (S/N = 3), repeatability and reproducibility were 1.03-1.50 ng mL(-1), 3.9-5.1% and 7.3-8.2%, respectively. The total analysis time was 10.0 min. Copyright 2003 John Wiley & Sons, Ltd.

  19. Comparison of accelerator mass spectrometric measurement with liquid scintillation counting measurement for the determination of 14C in environmental samples

    International Nuclear Information System (INIS)

    Yasuike, Kaeko; Yamada, Yoshimune; Amano, Hikaru

    2010-01-01

    The concentrations of organically-bound 14 C in tree-ring cellulose of a Japanese Black Pine grown in Shika-machi (37.0 deg. N, 136.8 deg. E) and those of a Japanese Cedar grown in Kanazawa (36.5 deg. N, 136.7 deg. E), Japan, were analyzed for the ring-years from 1989 to 1998 by the accelerator mass spectrometric measurement. The results were compared with those of the same samples analyzed by the liquid scintillation counting measurement to determine the reliability of liquid scintillation counting measurement. An important result of this study is that the sensitivity and reproducibility of accelerator mass spectrometric measurement was almost equal to that of liquid scintillation counting measurement.

  20. Midinfrared absorption measured at a lambda/400 resolution with an atomic force microscope.

    Science.gov (United States)

    Houel, Julien; Homeyer, Estelle; Sauvage, Sébastien; Boucaud, Philippe; Dazzi, Alexandre; Prazeres, Rui; Ortéga, Jean-Michel

    2009-06-22

    Midinfrared absorption can be locally measured using a detection combining an atomic force microscope and a pulsed excitation. This is illustrated for the midinfrared bulk GaAs phonon absorption and for the midinfrared absorption of thin SiO(2) microdisks. We show that the signal given by the cantilever oscillation amplitude of the atomic force microscope follows the spectral dependence of the bulk material absorption. The absorption spatial resolution achieved with microdisks is around 50 nanometer for an optical excitation around 22 micrometer wavelength.

  1. Metal ion analysis in contaminated water samples using anodic stripping voltammetry and a nanocrystalline diamond thin-film electrode

    International Nuclear Information System (INIS)

    Sonthalia, Prerna; McGaw, Elizabeth; Show, Yoshiyuki; Swain, Greg M.

    2004-01-01

    Boron-doped nanocrystalline diamond thin-film electrodes were employed for the detection and quantification of Ag (I), Cu (II), Pb (II), Cd (II), and Zn (II) in several contaminated water samples using anodic stripping voltammetric (ASV). Diamond is an alternate electrode that possesses many of the same attributes as Hg and, therefore, appears to be a viable material for this electroanalytical measurement. The nanocrystalline form has been found to perform slightly better than the more conventional microcrystalline form of diamond in this application. Differential pulse voltammetry (DPASV) was used to detect these metal ions in lake water, well water, tap water, wastewater treatment sludge, and soil. The electrochemical results were compared with data from inductively coupled plasma mass spectrometric (ICP-MS) and or atomic absorption spectrometric (AAS) measurements of the same samples. Diamond is shown to function well in this electroanalytical application, providing a wide linear dynamic range, a low limit of quantitation, excellent response precision, and good response accuracy. For the analysis of Pb (II), bare diamond provided a response nearly identical to that obtained with a Hg-coated glassy carbon electrode

  2. GMRT Detection of HI 21 cm Associated Absorption towards the z ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Comparison of the radio and deep optical images .... Astronomical Image Processing System (AIPS) following standard procedures. About .... exhibits an HI absorption spectrum similar to that seen in 3C 190, viz., a broad shallow feature and ...

  3. Intensity-Stabilized Fast-Scanned Direct Absorption Spectroscopy Instrumentation Based on a Distributed Feedback Laser with Detection Sensitivity down to 4 × 10−6

    Directory of Open Access Journals (Sweden)

    Gang Zhao

    2016-09-01

    Full Text Available A novel, intensity-stabilized, fast-scanned, direct absorption spectroscopy (IS-FS-DAS instrumentation, based on a distributed feedback (DFB diode laser, is developed. A fiber-coupled polarization rotator and a fiber-coupled polarizer are used to stabilize the intensity of the laser, which significantly reduces its relative intensity noise (RIN. The influence of white noise is reduced by fast scanning over the spectral feature (at 1 kHz, followed by averaging. By combining these two noise-reducing techniques, it is demonstrated that direct absorption spectroscopy (DAS can be swiftly performed down to a limit of detection (LOD (1σ of 4 × 10−6, which opens up a number of new applications.

  4. Detecting pM concentrations of prostaglandins in cell culture supernatants by capillary SCX-LC-MS/MS

    DEFF Research Database (Denmark)

    Dahl, Sandra Rinne; Kleiveland, Charlotte Ramstad; Kassem, Moustapha

    2008-01-01

    A highly sensitive, improved online strong cation exchange (SCX)--RP capillary liquid chromatographic (cLC) method with IT mass spectrometric (IT-MS/MS) detection for the simultaneous determination of prostaglandin (PG)A(1), PGD(2), PGE(1), PGE(2), PGF(2alpha), 8-iso-(8i)PGF(2alpha), 6-keto-(6k...

  5. The AS-76 interlaboratory experiment on the alpha spectrometric determination of Pu-238. Pt. 1

    International Nuclear Information System (INIS)

    Beyrich, W.; Spannagel, G.

    1979-12-01

    In cooperation with 26 laboratories of 11 countries or international organizations, the Safeguards Project of the Karlsruhe Nuclear Research Center carried out the interlaboratory program AS-76. It focused on the alpha-spectrometric determination of the Pu-238 isotope. The performance of the program as well as the results obtained are described. (orig.) 891 HP/orig. 892 MKO [de

  6. Mass spectrometric characterization of circulating and functional antigens derived from piperacillin in patients with cystic fibrosis1

    Science.gov (United States)

    Whitaker, Paul; Meng, Xiaoli; Lavergne, Sidonie N.; El-Ghaiesh, Sabah; Monshi, Manal; Earnshaw, Caroline; Peckham, Daniel; Gooi, Jimmy; Conway, Steve; Pirmohamed, Munir; Jenkins, Rosalind E.; Naisbitt, Dean J.; Park, B. Kevin

    2011-01-01

    A mechanistic understanding of the relationship between the chemistry of drug antigen formation and immune function is lacking. Thus, mass spectrometric methods were employed to detect and fully characterize circulating antigens derived from piperacillin in patients undergoing therapy and the nature of the drug derived-epitopes on protein which can function as an antigen to stimulate T-cells. Albumin modification with piperacillin in vitro resulted in the formation of two distinct haptens, one formed directly from piperacillin and a second in which the dioxopiperazine ring had undergone hydrolysis. Modification was time- and concentration-dependent, with selective modification of Lys541 observed at low concentrations, whereas at higher concentrations up to 13/59 lysine residues were modified, four of which (Lys190, 195, 432 and 541) were detected in patients’ plasma. Piperacillin-specific T-lymphocyte responses (proliferation, cytokines and granzyme-B release) were detected ex vivo with cells from hypersensitive patients, and analysis of incubation medium showed that modification of the same lysine residues in albumin occurred in situ. The antigenicity of piperacillin-modified albumin was confirmed by stimulation of T-cells with characterized synthetic conjugates. Analysis of minimally-modified T-cell stimulatory albumin conjugates revealed peptide sequences incorporating Lys190, 432 and 541 as principal functional epitopes for T-cells. This study has characterized the multiple haptenic structures on albumin in patients, and showed that they constitute functional antigenic determinants for T-cells. PMID:21606251

  7. Application of tunable diode laser absorption spectroscopy in the detection of oxygen

    Science.gov (United States)

    Zhou, Xin; Jin, Xing

    2015-10-01

    Most aircrafts is driven by chemic energy which is released in the combustion process. For improving the capability of engine and controlling the running on-time, the processes of fuel physics and chemistry need to be analysis by kinds of high quality sensor. In the research of designing and improving the processes of fuel physics and chemistry, the concentration, temperature and velocity of kinds of gas in the combustor need to be detected and measured. In addition, these engines and research equipments are always in the harsh environment of high temperature, high pressure and high speed. The harsh environment needs the sensor to be high reliability, well repetition, no cross- sensitivity between gases, and the traditional measurement system can't satisfy the metrical requirement well. Tunable diode laser absorption spectroscopy (TDLAS) analytic measurement technology can well satisfy the measurement in the harsh environment, which can support the whole measurement plan and high quality measurement system. Because the TDLAS sensor has the excellence of small bulk, light weight, high reliability and well specifically measurement, the TDLAS measurement technology has wide prospects. Different from most measurements, only a beam of laser can be pass through the measured environment by TDLAS, and the measurement equipment needn't be set in the harsh environment. So, the TDLAS equipment can't be interrupted by the measured equipment. The ability of subsistence in the harsh environment is very valuable, especially in the measurement on the subject of aerospace with environment of high speed, combustion and plasma. This paper focuses on the collecting the articles on the subject of oxygen detection of TDLAS. By analyzing the research and results of the articles, we conclude the central issues, difficulties and results. And we can get some instructive conclusions.

  8. Radionuclides and trace metals in surface air

    International Nuclear Information System (INIS)

    Feely, H.W.; Toonkel, L.E.; Larsen, R.J.

    1979-01-01

    Samples are collected at 49 selected world-wide monitoring sites located between 71 0 N and 90 0 S longitude. The samples are composited for each station and subjected to gamma spectrometric, radiochemical, absorption spectrometric, and x-ray fluorescence analyses. The data are reported as composite monthly concentrations for each sampling site. The data are presented in tabular form

  9. Aerosol absorption measurement with a sinusoidal phase modulating fiber optic photo thermal interferometer

    Science.gov (United States)

    Li, Shuwang; Shao, Shiyong; Mei, Haiping; Rao, Ruizhong

    2016-10-01

    Aerosol light absorption plays an important role in the earth's atmosphere direct and semi-direct radiate forcing, simultaneously, it also has a huge influence on the visibility impairment and laser engineering application. Although various methods have been developed for measuring aerosol light absorption, huge challenge still remains in precision, accuracy and temporal resolution. The main reason is that, as a part of aerosol light extinction, aerosol light absorption always generates synchronously with aerosol light scattering, and unfortunately aerosol light scattering is much stronger in most cases. Here, a novel photo-thermal interferometry is proposed only for aerosol absorption measurement without disturbance from aerosol scattering. The photo-thermal interferometry consists of a sinusoidal phase-modulating single mode fiber-optic interferometer. The thermal dissipation, caused by aerosol energy from photo-thermal conversion when irritated by pump laser through interferometer, is detected. This approach is completely insensitive to aerosol scattering, and the single mode fiber-optic interferometer is compact, low-cost and insensitive to the polarization shading. The theory of this technique is illustrated, followed by the basic structure of the sinusoidal phase-modulating fiber-optic interferometer and demodulation algorithms. Qualitative and quantitative analysis results show that the new photo-thermal interference is a potential approach for aerosol absorption detection and environmental pollution detection.

  10. Spectroscopic and Spectrometric Methods Used for the Screening of Certain Herbal Food Supplements Suspected of Adulteration.

    Science.gov (United States)

    Mateescu, Cristina; Popescu, Anca Mihaela; Radu, Gabriel Lucian; Onisei, Tatiana; Raducanu, Adina Elena

    2017-06-01

    Purpose: This study was carried out in order to find a reliable method for the fast detection of adulterated herbal food supplements with sexual enhancement claims. As some herbal products are advertised as "all natural", their "efficiency" is often increased by addition of active pharmaceutical ingredients such as PDE-5 inhibitors, which can be a real health threat for the consumer. Methodes: Adulterants, potentially present in 50 herbal food supplements with sexual improvement claims, were detected using 2 spectroscopic methods - Raman and Fourier Transform Infrared - known for reliability, reproductibility, and an easy sample preparation. GC-MS technique was used to confirm the potential adulterants spectra. Results: About 22% (11 out of 50 samples) of herbal food supplements with sexual enhancement claims analyzed by spectroscopic and spectrometric methods proved to be "enriched" with active pharmaceutical compounds such as: sildenafil and two of its analogues, tadalafil and phenolphthalein. The occurence of phenolphthalein could be the reason for the non-relevant results obtained by FTIR method in some samples. 91% of the adulterated herbal food supplements were originating from China. Conclusion: The results of this screening highlighted the necessity for an accurate analysis of all alleged herbal aphrodisiacs on the Romanian market. This is a first such a screening analysis carried out on herbal food supplements with sexual enhancement claims.

  11. Determination of trace metals in non-conventional oilseeds and oil bearing resources by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Anwer, T.; Kazi, T.G.; Bhanger, M.I.; Iqbal, S.; Anwar, F.

    2003-01-01

    The presence of small amount of trace metals in oil and fats is well known to produce deleterious effect. Crude oils and fat of rice bran varieties (super, 86), mango kernel and muskmelon were evaluated for the determination of Ca, Mg, and Zn by using atomic absorption spectrometric technique. Both rice bran varieties (super, 86) were found to contain high calcium content 12.72, 12.11 micro g/g respectively. In case of Mg, highest content noted in mango kernel 9.91 micro g/g and lowest concentration was in rice bran (super) 2.23 micro g/g. The concentration of Zn was high in rice bran (86) 21.0 micro g/g followed by mango kernel 14.4 micro g/g, rice bran (super) 12.20 micro g/g and muskmelon 8.71 micro g/g. The information gained in present study provides baseline for the stability of these oils. (author)

  12. Determination of copper in powdered chocolate samples by slurry-sampling flame atomic-absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Walter N.L. dos; Silva, Erik G.P. da; Fernandes, Marcelo S.; Araujo, Rennan G.O.; Costa, Anto' ' enio C.S.; Ferreira, Sergio L.C. [Nucleo de Excelencia em Quimica Analitica da Bahia, Universidade Federal da Bahia, Instituto de Quimica, Salvador, Bahia (Brazil); Vale, M.G.R. [Instituto de Quimica, Universidade Federal da Bahia do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul (Brazil)

    2005-06-01

    Chocolate is a complex sample with a high content of organic compounds and its analysis generally involves digestion procedures that might include the risk of losses and/or contamination. The determination of copper in chocolate is important because copper compounds are extensively used as fungicides in the farming of cocoa. In this paper, a slurry-sampling flame atomic-absorption spectrometric method is proposed for determination of copper in powdered chocolate samples. Optimization was carried out using univariate methodology involving the variables nature and concentration of the acid solution for slurry preparation, sonication time, and sample mass. The recommended conditions include a sample mass of 0.2 g, 2.0 mol L{sup -1} hydrochloric acid solution, and a sonication time of 15 min. The calibration curve was prepared using aqueous copper standards in 2.0 mol L{sup -1} hydrochloric acid. This method allowed determination of copper in chocolate with a detection limit of 0.4 {mu}g g{sup -1} and precision, expressed as relative standard deviation (RSD), of 2.5% (n=10) for a copper content of approximately 30 {mu}g g{sup -1}, using a chocolate mass of 0.2 g. The accuracy was confirmed by analyzing the certified reference materials NIST SRM 1568a rice flour and NIES CRM 10-b rice flour. The proposed method was used for determination of copper in three powdered chocolate samples, the copper content of which varied between 26.6 and 31.5 {mu}g g{sup -1}. The results showed no significant differences with those obtained after complete digestion, using a t-test for comparison. (orig.)

  13. Cu2+-assisted two dimensional charge-mass double focusing gel electrophoresis and mass spectrometric analysis of histone variants.

    Science.gov (United States)

    Zhang, Wenyang; Tang, Xuemei; Ding, Mengjie; Zhong, Hongying

    2014-12-10

    Abundant isoforms and dynamic posttranslational modifications cause the separation and identification of histone variants to be experimentally challenging. To meet this need, we employ two-dimensional electrophoretic gel separation followed by mass spectrometric detection which takes advantage of the chelation of Cu(2+) with amino acid residues exposed on the surfaces of the histone proteins. Acid-extracted rat liver histones were first mixed with CuSO4 solution and then separated in one dimension with triton-acid-urea (TAU) gel electrophoresis and in a second dimension using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The separations result from both the changes in charge and mass upon Cu(2+) chelation. Identities of each separated gel bands were obtained by using matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS). It was found that the migration of H3 histone isoforms of rat liver is markedly affected by the use of Cu(2+) ions. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. VARIATIONS OF ABSORPTION TROUGHS IN THE QUASAR SDSS J125216.58+052737.7

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhi-Fu [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Qin, Yi-Ping, E-mail: zhichenfu@126.com [Department of Physics and Telecommunication Engineering, Baise University, Baise 533000 (China)

    2015-01-20

    In this work, we analyze the spectra of quasar J125216.58+052737.7 (z {sub em} = 1.9035) which was observed by SDSS-I/II on 2003 January 30 and by BOSS on 2011 April 2. Both the continuum and the absorption spectra of this quasar show obvious variations between the two epochs. In the SDSS-I/II spectrum, we detect 8 C IV λλ1548,1551 absorption systems, which are detected at z {sub abs} = 1.9098, 1.8948, 1.8841, 1.8770, 1.8732, 1.8635, 1.8154, and 1.7359, respectively, and one Mg II λλ2796,2803 absorption system at z {sub abs} = 0.9912. Among these absorption systems, two C IV λλ1548,1551 absorption systems at z {sub abs} = 1.9098 and 1.7359 and the Mg II λλ2796,2803 absorption system are imprinted on the BOSS spectrum as well, and have similar absorption strengths when compared to those measured from the SDSS-I/II spectrum. Three C IV λλ1548,1551 absorption systems at z {sub abs} = 1.8948, 1.8841, and 1.8770 are also detected in the BOSS spectrum, while their absorption strengths are much weaker than those measured from the SDSS-I/II spectrum; three systems at z {sub abs} = 1.8732, 1.8635, and 1.8154 disappeared from the BOSS spectrum. Based on the variability analysis, the absorption systems that disappeared and weakened are likely to be intrinsic to the quasar. If these intrinsic absorption gases are blown away from the central region of the quasar, with respect to the quasar system, the absorption systems that disappeared would have separation velocities of 3147 kms{sup –1}, 4161 km s{sup –1}, and 9241 km s{sup –1}, while the absorption systems that weakened would have separation velocities of 900 km s{sup –1}, 2011 km s{sup –1}, and 2751 km s{sup –1}. Well-coordinated variations of the six C IV λλ1548,1551 absorption systems that disappeared and weakened, occurring on a timescale of 1026.7 days at the quasar rest frame, can be interpreted as a result of global changes in the ionization state of the absorbing gas.

  15. Development and validation of LC-MS/MS assay for the determination of Butoconazole in human plasma: Evaluation of systemic absorption following topical application in healthy volunteers

    Directory of Open Access Journals (Sweden)

    Eman G. Nouman

    2017-12-01

    Full Text Available Butoconazole is an imidazole antifungal that is more effective than miconazole and clotrimazole for treatment of vaginal candidiasis. A highly sensitive tandem mass spectrometric assay was developed and validated to evaluate systemic absorption of Butoconazole following intravaginal administration. Chromatographic separation was achieved using Waters Xterra C18 column (3 µm, 3.0 × 50.0 mm. Liquid-liquid extraction using tert-butyl methyl ether was used for preparation of plasma samples. The mobile phase was solvent A: 0.1% formic acid in water and solvent B: acetonitrile: methanol (30:70, v/v, using gradient elution mode at 0.5 mL/min. Detection at positive electrospray ionization in the MRM mode was then employed. Analysis was carried out within 5.5 min over a linear concentration range of 0.10–30.00 ng/mL. Validation was carried out according to US FDA guidelines for bioanalytical method validation. Matrix effect, recovery efficiency and process efficiency have been investigated for the analyte and internal standard in neat solvent, post-extraction matrix and plasma. The mean percentage recoveries were higher than 80%, the accuracy was 93.51–106.85% and the RSD was below 10% throughout the studied concentration range. Results indicated sufficient stability of the target analyte in plasma at the employed experimental conditions. Results of incurred sample re-analysis and incurred sample stability revealed less than 5% variability. The applicability of the assay for monitoring of the systemic absorption of Butoconazole following intra vaginal application to healthy volunteers was demonstrated. Results confirmed that Butoconazole was detected shortly after intra vaginal administration with Cmax and tmax of 30 ng/mL and 6 h, respectively. Keywords: Butoconazole, LC-MS/MS, Matrix effect, Process efficiency, Recovery efficiency

  16. Photoacoustic Experimental System to Confirm Infrared Absorption Due to Greenhouse Gases

    Science.gov (United States)

    Kaneko, Fumitoshi; Monjushiro, Hideaki; Nishiyama, Masayoshi; Kasai, Toshio; Harris, Harold H.

    2010-01-01

    An experimental system for detecting infrared absorption using the photoacoustic (PA) effect is described. It is aimed for use at high-school level to illustrate the difference in infrared (IR) absorption among the gases contained in the atmosphere in connection with the greenhouse effect. The experimental system can be built with readily…

  17. On the nature of absorption features toward nearby stars

    Science.gov (United States)

    Kohl, S.; Czesla, S.; Schmitt, J. H. M. M.

    2016-06-01

    Context. Diffuse interstellar absorption bands (DIBs) of largely unknown chemical origin are regularly observed primarily in distant early-type stars. More recently, detections in nearby late-type stars have also been claimed. These stars' spectra are dominated by stellar absorption lines. Specifically, strong interstellar atomic and DIB absorption has been reported in τ Boo. Aims: We test these claims by studying the strength of interstellar absorption in high-resolution TIGRE spectra of the nearby stars τ Boo, HD 33608, and α CrB. Methods: We focus our analysis on a strong DIB located at 5780.61 Å and on the absorption of interstellar Na. First, we carry out a differential analysis by comparing the spectra of the highly similar F-stars, τ Boo and HD 33608, whose light, however, samples different lines of sight. To obtain absolute values for the DIB absorption, we compare the observed spectra of τ Boo, HD 33608, and α CrB to PHOENIX models and carry out basic spectral modeling based on Voigt line profiles. Results: The intercomparison between τ Boo and HD 33608 reveals that the difference in the line depth is 6.85 ± 1.48 mÅ at the DIB location which is, however, unlikely to be caused by DIB absorption. The comparison between PHOENIX models and observed spectra yields an upper limit of 34.0 ± 0.3 mÅ for any additional interstellar absorption in τ Boo; similar results are obtained for HD 33608 and α CrB. For all objects we derive unrealistically large values for the radial velocity of any presumed interstellar clouds. In τ Boo we find Na D absorption with an equivalent width of 0.65 ± 0.07 mÅ and 2.3 ± 0.1 mÅ in the D2 and D1 lines. For the other Na, absorption of the same magnitude could only be detected in the D2 line. Our comparisons between model and data show that the interstellar absorption toward τ Boo is not abnormally high. Conclusions: We find no significant DIB absorption in any of our target stars. Any differences between modeled and

  18. Electrospray ionization mass spectrometric investigations of [alpha]-dicarbonyl compounds--Probing intermediates formed in the course of the nonenzymatic browning reaction of l-ascorbic acid

    Science.gov (United States)

    Schulz, Anke; Trage, Claudia; Schwarz, Helmut; Kroh, Lothar W.

    2007-05-01

    A new method is presented which allows the simultaneous detection of various [alpha]-dicarbonyl compounds generated in the course of the nonenzymatic browning reaction initiated by thermal treatment of l-ascorbic acid, namely: glyoxal, methylglyoxal, diacetyl, 3-deoxy-l-pentosone, and l-threosoneE 3-Deoxy-l-threosone was successfully identified as a new C4-[alpha]-dicarbonyl structure for the first time in the degradation of Vitamin C by application of this non-chromatographic mass spectrometric approach. Moreover, a more detailed elucidation of the mechanistic scenario with respect to the oxidative and nonoxidative pathways is presented by using dehydro-l-ascorbic acid and 2,3-diketo-l-gulonic acid instead of l-ascorbic acid as a starting material. Furthermore, the postulated pathways are corroborated with the aid of 13C-isotopic labeling studies. The investigations were extended to baby food, and the successful detection of [alpha]-dicarbonyl compounds characteristic for Vitamin C degradation proved the matrix tolerance of the introduced method.

  19. CIRCUMSTELLAR SHELLS IN ABSORPTION IN TYPE Ia SUPERNOVAE

    International Nuclear Information System (INIS)

    Borkowski, Kazimierz J.; Blondin, John M.; Reynolds, Stephen P.

    2009-01-01

    Progenitors of Type Ia supernovae (SNe) have been predicted to modify their ambient circumstellar (CSM) and interstellar environments through the action of their powerful winds. While there is X-ray and optical evidence for circumstellar interaction in several remnants of Type Ia SNe, widespread evidence for such interaction in Type Ia SNe themselves has been lacking. We consider prospects for the detection of CSM shells that have been predicted to be common around Type Ia SNe. Such shells are most easily detected in Na I absorption lines. Variable (declining) absorption is expected to occur soon after the explosion, primarily during the SN rise time, for shells located within ∼1-10 pc of a SN. The distance of the shell from the SN can be determined by measuring the timescale for line variability.

  20. A liquid chromatography-mass spectrometric method for the determination of oak moss allergens atranol and chloroatranol in perfumes

    DEFF Research Database (Denmark)

    Bossi, Rossana; Rastogi, Suresh Chandra; Bernard, Guillaume

    2004-01-01

    This paper describes a validated liquid chromatographic-tandem mass spectrometric method for quantitative analysis of the potential oak moss allergens atranol and chloroatranol in perfumes and similar products. The method employs LC-MS-MS with electrospray ionization (ESI) in negative mode...

  1. VizieR Online Data Catalog: QSOs narrow absorption line variability (Hacker+, 2013)

    Science.gov (United States)

    Hacker, T. L.; Brunner, R. J.; Lundgren, B. F.; York, D. G.

    2013-06-01

    Catalogues of 2,522 QAL systems and 33 variable NAL systems detected in SDSS DR7 quasars with repeat observations. The object identifiers, position coordinates, and plate-MJD-fibre designations are taken from the SpecObjAll table in the SDSS Catalogue Archive Server (CAS) while the quasar redshifts (zqso) are from Hewett & Wild (2010, Cat. J/MNRAS/405/2302). The absorption system redshift (zabs), system grade, and detected lines are outputs of the York et al. (2013, in. prep.) QAL detection pipeline. Some absorption lines are flagged based on alternate identifications (a), proximity of masked pixels (b), or questionable continuum fits (c). (3 data files).

  2. SPATIALLY RESOLVED HCN ABSORPTION FEATURES IN THE CIRCUMNUCLEAR REGION OF NGC 1052

    Energy Technology Data Exchange (ETDEWEB)

    Sawada-Satoh, Satoko [Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, 2-12 Hoshigaoka-cho, Mizusawa-ku, Oshu, Iwate 023-0861 (Japan); Roh, Duk-Gyoo; Oh, Se-Jin; Lee, Sang-Sung; Byun, Do-Young; Yeom, Jae-Hwan; Jung, Dong-Kyu; Kim, Hyo-Ryoung; Hwang, Ju-Yeon [Korea Astronomy and Space Science Institute, 776 Daedeok-daero, Yuseong, Daejeon 34055 (Korea, Republic of); Kameno, Seiji, E-mail: satoko.ss@nao.ac.jp, E-mail: sss@mx.ibaraki.ac.jp [Joint ALMA Observatory, Alonso de Cordova 3107 Vitacura, Santiago 763 0355 (Chile)

    2016-10-10

    We present the first VLBI detection of HCN molecular absorption in the nearby active galactic nucleus NGC 1052. Utilizing the 1 mas resolution achieved by the Korean VLBI Network, we have spatially resolved the HCN absorption against a double-sided nuclear jet structure. Two velocity features of HCN absorption are detected significantly at the radial velocity of 1656 and 1719 km s{sup −1}, redshifted by 149 and 212 km s{sup −1} with respect to the systemic velocity of the galaxy. The column density of the HCN molecule is estimated to be 10{sup 15}–10{sup 16} cm{sup −2}, assuming an excitation temperature of 100–230 K. The absorption features show high optical depth localized on the receding jet side, where the free–free absorption occurred due to the circumnuclear torus. The size of the foreground absorbing molecular gas is estimated to be on approximately one-parsec scales, which agrees well with the approximate size of the circumnuclear torus. HCN absorbing gas is likely to be several clumps smaller than 0.1 pc inside the circumnuclear torus. The redshifted velocities of the HCN absorption features imply that HCN absorbing gas traces ongoing infall motion inside the circumnuclear torus onto the central engine.

  3. Detection of gastrointestinal cancer by elastic scattering and absorption spectroscopies with the Los Alamos Optical Biopsy System

    Energy Technology Data Exchange (ETDEWEB)

    Mourant, J.R.; Boyer, J.; Johnson, T.M.; Lacey, J.; Bigio, I.J. [Los Alamos National Lab., NM (United States); Bohorfoush, A. [Wisconsin Medical School, Milwaukee, WI (United States). Dept. of Gastroenterology; Mellow, M. [Univ. of Oklahoma Medical School, Oklahoma City, OK (United States). Dept. of Gastroenterology

    1995-03-01

    The Los Alamos National Laboratory has continued the development of the Optical Biopsy System (OBS) for noninvasive, real-time in situ diagnosis of tissue pathologies. In proceedings of earlier SPIE conferences we reported on clinical measurements in the bladder, and we report here on recent results of clinical tests in the gastrointestinal tract. With the OBS, tissue pathologies are detected/diagnosed using spectral measurements of the elastic optical transport properties (scattering and absorption) of the tissue over a wide range of wavelengths. The use of elastic scattering as the key to optical tissue diagnostics in the OBS is based on the fact that many tissue pathologies, including a majority of cancer forms, exhibit significant architectural changes at the cellular and sub-cellular level. Since the cellular components that cause elastic scattering have dimensions typically on the order of visible to near-IR wavelengths, the elastic (Mie) scattering properties will be wavelength dependent. Thus, morphology and size changes can be expected to cause significant changes m an optical signature that is derived from the wavelength-dependence of elastic scattering. Additionally, the optical geometry of the OBS beneficially enhances its sensitivity for measuring absorption bands. The OBS employs a small fiber-optic probe that is amenable to use with any endoscope or catheter, or to direct surface examination, as well as interstitial needle insertion. Data acquistion/display time is <1 second.

  4. Iron K Features in the Quasar E 1821+643: Evidence for Gravitationally Redshifted Absorption?

    Science.gov (United States)

    Yaqoob, Tahir; Serlemitsos, Peter

    2005-01-01

    We report a Chandra high-energy grating detection of a narrow, redshifted absorption line superimposed on the red wing of a broad Fe K line in the z = 0.297 quasar E 1821+643. The absorption line is detected at a confidence level, estimated by two different methods, in the range approx. 2 - 3 sigma. Although the detection significance is not high enough to exclude a non-astrophysical origin, accounting for the absorption feature when modeling the X-ray spectrum implies that the Fe-K emission line is broad, and consistent with an origin in a relativistic accretion disk. Ignoring the apparent absorption feature leads to the conclusion that the Fe-K emission line is narrower, and also affects the inferred peak energy of the line (and hence the inferred ionization state of Fe). If the absorption line (at approx. 6.2 keV in the quasar frame) is real, we argue that it could be due to gravitationally redshifted Fe XXV or Fe XXVI resonance absorption within approx. 10 - 20 gravitational radii of the putative central black hole. The absorption line is not detected in earlier ASCA and Chandra low-energy grating observations, but the absorption line is not unequivocally ruled out by these data. The Chandra high-energy grating Fe-K emission line is consistent with an origin predominantly in Fe I-XVII or so. In an ASCA observation eight years earlier, the Fe-K line peaked at approx. 6.6 keV, closer to the energies of He-like Fe triplet lines. Further, in a Chandra low-energy grating observation the Fe-K line profile was double-peaked, one peak corresponding to Fe I-XVII or so, the other peak to Fe XXVI Ly alpha. Such a wide range in ionization state of Fe is not ruled out by the HEG and ASCA data either, and is suggestive of a complex structure for the line-emitter.

  5. Sequential mass spectrometric analysis of uranium and plutonium employing resin bead technique

    International Nuclear Information System (INIS)

    Ramakumar, K.L.; Aggarwal, S.K.; Chitambar, S.A.; Jain, H.C.

    1985-01-01

    Sequential mass spectrometric analysis of uranium and plutonium employing anion exchange resin bead technique is reported using a high sensitive single stage magnetic analyser instrument, the routinely employed rhenium double filament assembly and 0.5M HNO 3 as a wetting agent for loading the resin beads. A precision of bettter than 0.3per cent (2sigma) is obtained on the isotopic ratio measurements. However, extreme care has to be exercised to carry the resin bead experiments under ultra clean conditions so as to avoid pick up of contamination. (author)

  6. Mass energy-absorption coefficients and average atomic energy-absorption cross-sections for amino acids in the energy range 0.122-1.330 MeV

    Energy Technology Data Exchange (ETDEWEB)

    More, Chaitali V., E-mail: chaitalimore89@gmail.com; Lokhande, Rajkumar M.; Pawar, Pravina P., E-mail: pravinapawar4@gmail.com [Department of physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad 431004 (India)

    2016-05-06

    Mass attenuation coefficients of amino acids such as n-acetyl-l-tryptophan, n-acetyl-l-tyrosine and d-tryptophan were measured in the energy range 0.122-1.330 MeV. NaI (Tl) scintillation detection system was used to detect gamma rays with a resolution of 8.2% at 0.662 MeV. The measured attenuation coefficient values were then used to determine the mass energy-absorption coefficients (σ{sub a,en}) and average atomic energy-absorption cross sections (μ{sub en}/ρ) of the amino acids. Theoretical values were calculated based on XCOM data. Theoretical and experimental values are found to be in good agreement.

  7. 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)

  8. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    Science.gov (United States)

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  9. Solid phase extraction of cadmium on 2-mercaptobenzothiazole loaded on sulfur powder in the medium of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate and cold vapor generation-atomic absorption spectrometric determination

    International Nuclear Information System (INIS)

    Pourreza, N.; Ghanemi, K.

    2010-01-01

    A novel solid phase extractor for preconcentration of cadmium at ng L -1 levels has been developed. Cadmium ions were retained on a column packed with sulfur powder modified with 2-mercaptobenzothiazole (2-MBT) in the medium of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] + PF 6 - ) ionic liquid. The presence of ionic liquid during modification of sulfur enhanced the retention of cadmium ions on the column. The retained cadmium ions were eluted with 2 mol L -1 solution of HCl and measured by cold vapor generation-atomic absorption spectrometry (CVG-AAS). By using reaction cell-gas liquid separator (RC-GLS), gaseous cadmium vapors were produced and reached the atomic absorption spectrometer, instantaneously. The influence of different variables on both processes of solid phase extraction and CVG-AAS determination of cadmium ions was investigated. The calibration curve was linear in the range of 10-200 ng L -1 of cadmium in the initial solution with r = 0.9992 (n = 8) under optimum conditions. The limit of detection based on three times the standard deviation of the blank (3S b , n = 10) was 4.6 ng L -1 . The relative standard deviation (R.S.D.) of 25 and 150 ng L -1 of cadmium was 4.1 and 2.2% (n = 8), respectively. The procedure was validated by the analysis of a certified reference material (DORM-3), water and fish samples.

  10. The Influence of Low Salivary Flow Rates on the Absorption of a Sublingual Fentanyl Citrate Formulation for Breakthrough Cancer Pain.

    Science.gov (United States)

    Davies, Andrew; Mundin, Gill; Vriens, Joanna; Webber, Kath; Buchanan, Alison; Waghorn, Melanie

    2016-03-01

    Salivary gland hypofunction may affect the absorption of drugs through the oral mucosa, which in turn may affect their clinical efficacy (e.g., onset of action). The aim of this study was to assess the pharmacokinetics of a sublingual fentanyl orally disintegrating tablet (Abstral, Prostrakan Inc.) in a group of cancer patients with salivary gland hypofunction. Nine cancer patients with salivary gland hypofunction underwent a series of three pharmacokinetic studies with the sublingual fentanyl orally disintegrating tablet. In the first phase, the patients received no pretreatment; in the second phase, the patients were allowed to moisten the oral cavity before dosing; in the third phase, the patients were given pilocarpine hydrochloride (saliva stimulant) before dosing. Fentanyl concentrations were measured using a method of high-performance liquid chromatography with validated tandem mass spectrometric detection. The Tmax was longer, the Cmax was lower, the AUC0-30 lower, and the AUClast lower in the phase involving no pretreatment; the Tmax/Cmax/AUC0-30/AUClast were similar in the phase involving moistening of the oral cavity and the phase involving giving pilocarpine hydrochloride. The pharmacokinetics of the sublingual fentanyl orally disintegrating tablet appear to be negatively affected by the presence of salivary gland hypofunction, although the moistening of the oral cavity before dosing results in a pharmacokinetic profile similar to that seen with the giving of pilocarpine hydrochloride. Copyright © 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

  11. Determination of radium isotopes by BaSO4 coprecipitation for the preparation of alpha-spectrometric sources

    International Nuclear Information System (INIS)

    Lozano, J.C.; Fernandez, F.; Gomez, J.M.G.

    1997-01-01

    A coprecipitation procedure for the preparation of α-spectrometric sources for radium, using BaSO 4 as carrier, has been applied to the determination of alpha radium isotopes in water samples. The use of 133 Ba as a suitable tracer for radium determination and possible losses of radon isotopes from the sources are studied and discussed. (author)

  12. Two-photon absorption of a supramolecular pseudoisocyanine J-aggregate assembly

    International Nuclear Information System (INIS)

    Belfield, Kevin D.; Bondar, Mykhailo V.; Hernandez, Florencio E.; Przhonska, Olga V.; Yao, Sheng

    2006-01-01

    Linear spectral properties, including excitation anisotropy, of pseudoisocyanine or 1,1'-diethyl-2,2'-cyanine iodide (PIC) J-aggregates in aqueous solutions with J-band position at 573 nm were investigated. Two-photon absorption of PIC J-aggregates and monomer molecules was studied using an open aperture Z-scan technique. A strong enhancement of the two-photon absorption cross-section of PIC in the supramolecular J-aggregate assembly was observed in aqueous solution. This enhancement is attributed to a strong coupling of the molecular transition dipoles. No two-photon absorption at the peak of the J-band was detected

  13. Isotope Enrichment Detection by Laser Ablation - Laser Absorption Spectrometry: Automated Environmental Sampling and Laser-Based Analysis for HEU Detection

    International Nuclear Information System (INIS)

    Anheier, Norman C.; Bushaw, Bruce A.

    2010-01-01

    The global expansion of nuclear power, and consequently the uranium enrichment industry, requires the development of new safeguards technology to mitigate proliferation risks. Current enrichment monitoring instruments exist that provide only yes/no detection of highly enriched uranium (HEU) production. More accurate accountancy measurements are typically restricted to gamma-ray and weight measurements taken in cylinder storage yards. Analysis of environmental and cylinder content samples have much higher effectiveness, but this approach requires onsite sampling, shipping, and time-consuming laboratory analysis and reporting. Given that large modern gaseous centrifuge enrichment plants (GCEPs) can quickly produce a significant quantity (SQ ) of HEU, these limitations in verification suggest the need for more timely detection of potential facility misuse. The Pacific Northwest National Laboratory (PNNL) is developing an unattended safeguards instrument concept, combining continuous aerosol particulate collection with uranium isotope assay, to provide timely analysis of enrichment levels within low enriched uranium facilities. This approach is based on laser vaporization of aerosol particulate samples, followed by wavelength tuned laser diode spectroscopy to characterize the uranium isotopic ratio through subtle differences in atomic absorption wavelengths. Environmental sampling (ES) media from an integrated aerosol collector is introduced into a small, reduced pressure chamber, where a focused pulsed laser vaporizes material from a 10 to 20-(micro)m diameter spot of the surface of the sampling media. The plume of ejected material begins as high-temperature plasma that yields ions and atoms, as well as molecules and molecular ions. We concentrate on the plume of atomic vapor that remains after the plasma has expanded and then cooled by the surrounding cover gas. Tunable diode lasers are directed through this plume and each isotope is detected by monitoring absorbance

  14. The gas-chromatographic and gas-chromatographic-mass-spectrometric identification of halogen-containing organic compounds

    Science.gov (United States)

    Gidaspov, B. V.; Zenkevich, I. G.; Rodin, A. A.

    1989-09-01

    The problem of identifying halogen-containing organic compounds in their gas-chromatographic and gas-chromatographic-mass-spectrometric (GC-MS) determination in different materials has been examined. Particular attention has been paid not to the complete characterisation of methods for carrying out this analysis but to the most important problem of increasing the selectivity at the stages of sampling, separation, and interpretation of the gas-chromatographic and GC-MS information. The bibliography contains 292 references.

  15. Determination of boron isotope ratios by high-resolution continuum source molecular absorption spectrometry using graphite furnace vaporizers

    Science.gov (United States)

    Abad, Carlos; Florek, Stefan; Becker-Ross, Helmut; Huang, Mao-Dong; Heinrich, Hans-Joachim; Recknagel, Sebastian; Vogl, Jochen; Jakubowski, Norbert; Panne, Ulrich

    2017-10-01

    Boron isotope amount ratios n(10B)/n(11B) have been determined by monitoring the absorption spectrum of boron monohydride (BH) in a graphite furnace using high-resolution continuum source molecular absorption spectrometry (HR-CS-MAS). Bands (0 → 0) and (1 → 1) for the electronic transition X1Σ+ → A1Π were evaluated around wavelengths 433.1 nm and 437.1 nm respectively. Clean and free of memory effect molecular spectra of BH were recorded. In order to eliminate the memory effect of boron, a combination of 2% (v/v) hydrogen gas in argon and 1% trifluoromethane in argon, an acid solution of calcium chloride and mannitol as chemical modifiers was used. Partial least square regression (PLS) for analysis of samples and reference materials were applied. For this, a spectral library with different isotopes ratios for PLS regression was built. Results obtained around the 433.1 nm and 437.1 nm spectral regions are metrologically compatible with those reported by mass spectrometric methods. Moreover, for the evaluated region of 437 nm, an accuracy of 0.15‰ is obtained as the average deviation from the isotope reference materials. Expanded uncertainties with a coverage factor of k = 2 range between 0.15 and 0.44‰. This accuracy and precision are compatible with those obtained by mass spectrometry for boron isotope ratio measurements.

  16. System to detect nuclear materials by active neutron method

    International Nuclear Information System (INIS)

    Koroev, M.; Korolev, Yu.; Lopatin, Yu.; Filonov, V.

    1999-01-01

    The report presents the results of the development of the system to detect nuclear materials by active neutron method measuring delayed neutrons. As the neutron source the neutron generator was used. The neutron generator was controlled by the system. The detectors were developed on the base of the helium-3 counters. Each detector consist of 6 counters. Using a number of such detectors it is possible to verify materials stored in different geometry. There is an spectrometric scintillator detector in the system which gives an additional functional ability to the system. The system could be used to estimate the nuclear materials in waste, to detect the unauthorized transfer of the nuclear materials, to estimate the material in tubes [ru

  17. Experimental characterization of the Clear-PEM scanner spectrometric performance

    Energy Technology Data Exchange (ETDEWEB)

    Bugalho, R; Carrico, B; Ferreira, C S; Frade, M; Ferreira, M; Moura, R; Ortigao, C; Pinheiro, J F; Rodrigues, P; Rolo, I; Silva, J C; Trindade, A; Varela, J [Laboratorio de Instrumentacao e Fisica Experimental de Particulas (LIP), Av. Elias Garcia 14-1, 1000-149 Lisboa (Portugal)], E-mail: frade@lip.pt

    2009-10-15

    In the framework of the Clear-PEM project for the construction of a high-resolution and high-specificity scanner for breast cancer imaging, a Positron Emission Mammography tomograph has been developed and installed at the Instituto Portugues de Oncologia do Porto hospital. The Clear-PEM scanner is mainly composed by two planar detector heads attached to a robotic arm, trigger/data acquisition electronics system and computing servers. The detector heads hold crystal matrices built from 2 x 2 x 20 mm{sup 3} LYSO:Ce crystals readout by Hamamatsu S8550 APD arrays. The APDs are optically coupled to both ends of the 6144 crystals in order to extract the DOI information for each detected event. Each one of 12288 APD's pixels is read and controlled by Application Specific Integrated Circuits water-cooled by an external cooling unit. The Clear-PEM frontend boards innovative design results in a unprecedented integration of the crystal matrices, APDs and ASICs, making Clear-PEM the PET scanner with the highest number of APD pixels ever integrated so far. In this paper, the scanner's main technical characteristics, calibration strategies and the first spectrometric performance evaluation in a clinical environment are presented. The first commissioning results show 99.7% active channels, which, after calibration, have inter-pixel and absolute gain distributions with dispersions of, respectively, 12.2% and 15.3%, demonstrating that despite the large number of channels, the system is uniform. The mean energy resolution at 511 keV is of 15.9%, with a 8.8% dispersion, and the mean C{sub DOI}{sup -1} is 5.9%/mm, with a 7.8% dispersion. The coincidence time resolution, at 511 keV, for a energy window between 400 and 600 keV, is 5.2 ns FWHM.

  18. Flame Atomic Absorption Spectrometric Determination of Ultra Traces of Thallium(I) ion after Solid Phase Extraction by Octadecyl Silica Membrane Disk Modified by a New Schiff Base

    International Nuclear Information System (INIS)

    Mashhadizadeh, Mohammad Hossein; Moatafavi, Ali; Allah-Abadi, Hossein; Zadmehr, Mohammad Reza

    2004-01-01

    A simple and reliable method has been developed to selectively separate and concentrate trace amounts of thallium ion from real samples for the subsequent measurement by flame atomic absorption spectrometry (FAAS). Thallium ions are absorbed quantitatively during passage of aqueous real samples through an octadecyl bonded silica membrane disk modified by 4-(4-Chloro-phenylazo)-2-[(4-hydroxy-phenylamino)- methyl]-phenol. The retained Tl + ions are then stripped from the disk quantitatively with a minimal amount of thiosulfate solution as eluent. The proposed method permitted large enrichment factors of about 130 and higher. The relative standard deviation for ten replicate extraction of thallium from 1 L samples containing 5 μg thallium is 1.2%. The break through volume for 5 μg thallium is 1000 mL. The limit of detection of the proposed method is 11.2 ng of Tl + per 1000 mL. The effects of various cationic interferences on the recovery of thallium in binary mixtures were studied. The method was applied to the recovery of Tl + ions from natural water and human hair samples

  19. Can high-performance liquid chromatography coupled with fluorescence detection under all conditions be regarded as a sufficiently conclusive confirmatory method for B-group substances?

    NARCIS (Netherlands)

    Zuidema, T.; Mulder, P.P.J.; Lasaroms, J.J.P.; Stappers, S.J.W.; Rhijn, van J.A.

    2006-01-01

    Commission Decision 2002/657/EC requires confirmatory analysis of B-group compounds when detected at levels above the permitted limit. In contrast to banned substances, for B-group substances, the use of mass spectrometric techniques is not obligatory and several techniques including liquid

  20. 'Intelligent' triggering methodology for improved detectability of wavelength modulation diode laser absorption spectrometry applied to window-equipped graphite furnaces

    International Nuclear Information System (INIS)

    Gustafsson, Joergen; Axner, Ove

    2003-01-01

    The wavelength modulation-diode laser absorption spectrometry (WM-DLAS) technique experiences a limited detectability when window-equipped sample compartments are used because of multiple reflections between components in the optical system (so-called etalon effects). The problem is particularly severe when the technique is used with a window-equipped graphite furnace (GF) as atomizer since the heating of the furnace induces drifts of the thickness of the windows and thereby also of the background signals. This paper presents a new detection methodology for WM-DLAS applied to a window-equipped GF in which the influence of the background signals from the windows is significantly reduced. The new technique, which is based upon a finding that the WM-DLAS background signals from a window-equipped GF are reproducible over a considerable period of time, consists of a novel 'intelligent' triggering procedure in which the GF is triggered at a user-chosen 'position' in the reproducible drift-cycle of the WM-DLAS background signal. The new methodology makes also use of 'higher-than-normal' detection harmonics, i.e. 4f or 6f, since these previously have shown to have a higher signal-to-background ratio than 2f-detection when the background signals originates from thin etalons. The results show that this new combined background-drift-reducing methodology improves the limit of detection of the WM-DLAS technique used with a window-equipped GF by several orders of magnitude as compared to ordinary 2f-detection, resulting in a limit of detection for a window-equipped GF that is similar to that of an open GF

  1. Cloud point extraction and flame atomic absorption spectrometric determination of cadmium and nickel in drinking and wastewater samples.

    Science.gov (United States)

    Naeemullah; Kazi, Tasneem G; Shah, Faheem; Afridi, Hassan I; Baig, Jameel Ahmed; Soomro, Abdul Sattar

    2013-01-01

    A simple method for the preconcentration of cadmium (Cd) and nickel (Ni) in drinking and wastewater samples was developed. Cloud point extraction has been used for the preconcentration of both metals, after formation of complexes with 8-hydroxyquinoline (8-HQ) and extraction with the surfactant octylphenoxypolyethoxyethanol (Triton X-114). Dilution of the surfactant-rich phase with acidified ethanol was performed after phase separation, and the Cd and Ni contents were measured by flame atomic absorption spectrometry. The experimental variables, such as pH, amounts of reagents (8-HQ and Triton X-114), temperature, incubation time, and sample volume, were optimized. After optimization of the complexation and extraction conditions, enhancement factors of 80 and 61, with LOD values of 0.22 and 0.52 microg/L, were obtained for Cd and Ni, respectively. The proposed method was applied satisfactorily for the determination of both elements in drinking and wastewater samples.

  2. Methodology of analysis of very weak acids by isotachophoresis with electrospray-ionization mass-spectrometric detection: Anionic electrolyte systems for the medium-alkaline pH range.

    Science.gov (United States)

    Malá, Zdena; Gebauer, Petr

    2018-01-15

    This work describes for the first time a functional electrolyte system setup for anionic isotachophoresis (ITP) with electrospray-ionization mass-spectrometric (ESI-MS) detection in the neutral to medium-alkaline pH range. So far no application was published on the analysis of very weak acids by anionic ITP-MS although there is a broad spectrum of potential analytes with pK a values in the range 5-10, where application of this technique promises interesting gains in both sensitivity and specificity. The problem so far was the lack of anionic ESI-compatible ITP systems in the mentioned pH range as all typical volatile anionic system components are fully ionized at neutral and alkaline pH and thus too fast to suit as terminators. We propose an original solution of the problem based on the combination of two ITP methods: (i) use of the hydroxyl ion as a natural and ESI-compatible terminator, and (ii) use of configurations based on moving-boundary ITP. The former method ensures effective stacking of analytes by an alkaline terminator of sufficiently low mobility and the latter offers increased flexibility for tuning of the separation window and selectivity according to actual needs. A theoretical description of the proposed model is presented and applied to the design of very simple functional electrolyte configurations. The properties of example systems are demonstrated by both computer simulation and experiments with a group of model analytes. Potential effects of carbon dioxide present in the solutions are demonstrated for particular systems. Experimental results confirm that the proposed methodology is well capable of performing sensitive and selective ITP-MS analyses of very weak acidic analytes (e.g. sulfonamides or chlorophenols). Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Uric acid detection using uv-vis spectrometer

    Science.gov (United States)

    Norazmi, N.; Rasad, Z. R. Abdul; Mohamad, M.; Manap, H.

    2017-10-01

    The aim of this research is to detect uric acid (UA) concentration using Ultraviolet-Visible (UV-Vis) spectrometer in the Ultraviolet (UV) region. Absorption technique was proposed to detect different uric acid concentrations and its UV absorption wavelength. Current practices commonly take a lot of times or require complicated structures for the detection process. By this proposed spectroscopic technique, every concentration can be detected and interpreted into an absorbance value at a constant wavelength peak in the UV region. This is due to the chemical characteristics belong to the uric acid since it has a particular absorption cross-section, σ which can be calculated using Beer’s Lambert law formula. The detection performance was displayed using Spectrasuite sofware. It showed fast time response about 3 seconds. The experiment proved that the concentrations of uric acid were successfully detected using UV-Vis spectrometer at a constant absorption UV wavelength, 294.46 nm in a low time response. Even by an artificial sample of uric acid, it successfully displayed a close value as the ones reported with the use of the medical sample. It is applicable in the medical field and can be implemented in the future for earlier detection of abnormal concentration of uric acid.

  4. Novel analytical reagent for the application of cloud-point preconcentration and flame atomic absorption spectrometric determination of nickel in natural water samples

    International Nuclear Information System (INIS)

    Suvardhan, K.; Rekha, D.; Kumar, K. Suresh; Prasad, P. Reddy; Kumar, J. Dilip; Jayaraj, B.; Chiranjeevi, P.

    2007-01-01

    Cloud-point extraction was applied as a preconcentration of nickel after formation of complex with newly synthesized N-quino[8,7-b]azin-5-yl-2,3,5,6,8,9,11,12octahydrobenzo[b][1,4,7,10,13] pentaoxacyclopentadecin-15-yl-methanimine, and later determined by flame atomic absorption spectrometry (FAAS) using octyl phenoxy polyethoxy ethanol (Triton X-114) as surfactant. Nickel was complexed with N-quino[8,7-b]azin-5-yl-2,3,5,6,8,9,11,12 octahydrobenzo[b][1,4,7,10,13]pentaoxacyclopentadecin-15-yl-methanimine in an aqueous phase and was kept for 15 min in a thermo-stated bath at 40 deg. C. Separation of the two phases was accomplished by centrifugation for 15 min at 4000 rpm. The chemical variables affecting the cloud-point extraction were evaluated, optimized and successfully applied to the nickel determination in various water samples. Under the optimized conditions, the preconcentration system of 100 ml sample permitted an enhancement factor of 50-fold. The detailed study of various interferences made the method more selective. The detection limits obtained under optimal condition was 0.042 ng ml -1 . The extraction efficiency was investigated at different nickel concentrations (20-80 ng ml -1 ) and good recoveries (99.05-99.93%) were obtained using present method. The proposed method has been applied successfully for the determination of nickel in various water samples and compared with reported method in terms of Student's t-test and variance ratio f-test which indicate the significance of present method over reported and spectrophotometric methods at 95% confidence level

  5. Standard test method for graphite furnace atomic absorption spectrometric determination of lead and cadmium extracted from ceramic foodware

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method covers procedures for using graphite furnace atomic absorption spectroscopy (GFAAS) to quantitatively determine lead and cadmium extracted by acetic acid at room temperature from the food-contact surface of foodware. The method is applicable to food-contact surfaces composed of silicate-based materials (earthenware, glazed ceramicware, decorated ceramicware, decorated glass, and lead crystal glass) and is capable of determining lead concentrations greater than 0.005 to 0.020 g/mL and cadmium concentrations greater than 0.0005 to 0.002 g/mL, depending on instrument design. 1.2 This test method also describes quality control procedures to check for contamination and matrix interference during GFAAS analyses and a specific sequence of analytical measurements that demonstrates proper instrument operation during the time period in which sample solutions are analyzed. 1.3 Cleaning and other contamination control procedures are described in this test method. Users may modify contamination cont...

  6. The comparison of benzene and CO2 absorption methods for radioisotope 14C dating

    International Nuclear Information System (INIS)

    Satrio and Zainal Abidin

    2007-01-01

    It had been conducted to research of age determination of carbon samples using CO 2 absorption method. This method as alternative to benzene synthesis method for radioisotope 14 C dating.The aim of the method is to support some hydrology research's especially groundwater dating using environmental radioisotope 14 C.The results which obtain by CO 2 absorption method then compared with the results of benzene synthesis method consists of background counter, standard counter, activity and age limit, age, and material cost or component. The research show that compared with benzene synthesis method, sample preparation using CO 2 absorption method is more simple and relatively low cost. The use of CO 2 absorption method can save the cost about 75 %. The different of both methods is age limit detection. The results of age limit detection when using CO 2 absorption and synthesis benzene methods are 33,310 years and 47,533 years respectively. Whereas, based on t test, the age results of both methods for the same sample are obtained relatively equal. (author)

  7. Mass Spectrometric Methodologies for Investigating the Metabolic Signatures of Parkinson's Disease: Current Progress and Future Perspectives.

    Science.gov (United States)

    Gill, Emily L; Koelmel, Jeremy P; Yost, Richard A; Okun, Michael S; Vedam-Mai, Vinata; Garrett, Timothy J

    2018-03-06

    Parkinson's disease (PD) is a neurodegenerative disorder resulting from the loss of dopaminergic neurons of the substantia nigra as well as degeneration of motor and nonmotor basal ganglia circuitries. Typically known for classical motor deficits (tremor, rigidity, bradykinesia), early stages of the disease are associated with a large nonmotor component (depression, anxiety, apathy, etc.). Currently, there are no definitive biomarkers of PD, and the measurement of dopamine metabolites does not allow for detection of prodromal PD nor does it aid in long-term monitoring of disease progression. Given that PD is increasingly recognized as complex and heterogeneous, involving several neurotransmitters and proteins, it is of importance that we advance interdisciplinary studies to further our knowledge of the molecular and cellular pathways that are affected in PD. This approach will possibly yield useful biomarkers for early diagnosis and may assist in the development of disease-modifying therapies. Here, we discuss preanalytical factors associated with metabolomics studies, summarize current mass spectrometric methodologies used to evaluate the metabolic signature of PD, and provide future perspectives of the rapidly developing field of MS in the context of PD.

  8. Absorption coefficients for water vapor at 193 nm from 300 to 1073 K

    Science.gov (United States)

    Kessler, W. J.; Carleton, K. L.; Marinelli, W. J.

    1993-01-01

    Measurements of the water absorption coefficient at 193 nm from 300 to 1073 K are reported. The measurements were made using broadband VUV radiation and a monochromator-based detection system. The water vapor was generated by a saturator and metered into a flowing, 99 cm absorption cell via a water vapor mass flow meter. The 193 nm absorption coefficient measurements are compared to room temperature and high temperature shock tube measurements with good agreement. The absorption can be parameterized by a nu3 vibrational mode reaction coordinate and the thermal population of the nu3 mode.

  9. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1999-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade uranium dioxide powders and pellets to determine compliance with specifications. 1.2 This test method covers the determination of uranium and the oxygen to uranium atomic ratio in nuclear-grade uranium dioxide powder and pellets. 1.4 This test method covers the determination of chlorine and fluorine in nuclear-grade uranium dioxide. With a 1 to 10-g sample, concentrations of 5 to 200 g/g of chlorine and 1 to 200 μg/g of fluorine are determined without interference. 1.5 This test method covers the determination of moisture in uranium dioxide samples. Detection limits are as low as 10 μg. 1.6 This test method covers the determination of nitride nitrogen in uranium dioxide in the range from 10 to 250 μg. 1.7 This test method covers the spectrographic analysis of nuclear-grade UO2 for the 26 elements in the ranges indicated in Table 2. 1.8 For simultaneous determination of trace ele...

  10. Determination of isotope fractionation effect using a double spike (242Pu+240Pu) during the mass spectrometric analysis of plutonium

    International Nuclear Information System (INIS)

    Chitambar, S.A.; Parab, A.R.; Khodade, P.S.; Jain, H.C.

    1986-01-01

    Isotope fractionation effect during the mass spectrometric analysis of plutonium has been investigated using a double spike ( 242 Pu+ 240 Pu) and the determination of concentration of plutonium in dissolver solution of irradiated fuel is reported. (author). 6 refs., 2 tables

  11. Ultrasensitive detection of explosives and chemical warfare agents by low-pressure photoionization mass spectrometry.

    Science.gov (United States)

    Sun, Wanqi; Liang, Miao; Li, Zhen; Shu, Jinian; Yang, Bo; Xu, Ce; Zou, Yao

    2016-08-15

    On-spot monitoring of threat agents needs high sensitive instrument. In this study, a low-pressure photoionization mass spectrometer (LPPI-MS) was employed to detect trace amounts of vapor-phase explosives and chemical warfare agent mimetics under ambient conditions. Under 10-s detection time, the limits of detection of 2,4-dinitrotoluene, nitrotoluene, nitrobenzene, and dimethyl methyl phosphonate were 30, 0.5, 4, and 1 parts per trillion by volume, respectively. As compared to those obtained previously with PI mass spectrometric techniques, an improvement of 3-4 orders of magnitude was achieved. This study indicates that LPPI-MS will open new opportunities for the sensitive detection of explosives and chemical warfare agents. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. 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

  13. Effects of UV radiation on the UV-VIS absorption spectra of the EAGLE's medium components

    International Nuclear Information System (INIS)

    Bollmann, G.; Redmann, K.

    1990-01-01

    The impact of ultraviolet light on uv/vis absorption spectra of selected individual components of the cell breeding medium according to Eagle (MEM) was investigated. The strongest alterations of light absorption were detected in L-phenylalanin, L-tyrosin and L-tryptophane. Thus, the absorption behaviour of the Eagle (MEM) medium changed post radiationem may be attributed to spectrophotometric alterations of absorption in aromatic amino acids. The results are discussed with regard to the effect on the surface charge of erythrocytes. (author)

  14. Flame atomic absorption spectrometric determination of trace amounts of Pb(II) and Cr(III) in biological, food and environmental samples after preconcentration by modified nano-alumina

    International Nuclear Information System (INIS)

    Afkhami, A.; Madrakian, T.; Saber-Tehrani, M.; Bagheri, H.

    2011-01-01

    A new solid-phase extraction sorbent was used for the preconcentration of Pb(II) and Cr(III) ions prior to their determination by flame atomic absorption spectrometry. It was prepared by immobilization of 2,4-dinitrophenylhydrazine on nano-alumina coated with sodium dodecyl sulfate. The sorbent was characterized by scanning electron microscopy, N 2 adsorption and Fourier transform infrared spectrometry, and used for preconcentration and separation of Pb(II) and Cr(III) from aqueous solutions. The ions on the sorbent were eluted with a mixture of nitric acid and methanol. The effects of sample pH, flow rates of samples and eluent, type of eluent, breakthrough volume and potentially interfering ions were studied. Linearity is maintained between 1.2 and 350 μg L -1 of Pb(II), and between 2.4 and 520 μg L -1 of Cr(III) for an 800-mL sample. The detection limit (3 s, N=10) for Pb(II) and Cr(III) ions is 0.43 and 0.55 μg L -1 , respectively, and the maximum preconcentration factor is 267. The method was successfully applied to the evaluation of these trace and toxic metals in various water, food, industrial effluent and urine samples. (author)

  15. 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

  16. Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

    Science.gov (United States)

    Petronijevic, E.; Leahu, G.; Belardini, A.; Centini, M.; Li Voti, R.; Hakkarainen, T.; Koivusalo, E.; Guina, M.; Sibilia, C.

    2018-03-01

    Semiconductor nanowires made of high refractive index materials can couple the incoming light to specific waveguide modes that offer resonant absorption enhancement under the bandgap wavelength, essential for light harvesting, lasing and detection applications. Moreover, the non-trivial ellipticity of such modes can offer near field interactions with chiral molecules, governed by near chiral field. These modes are therefore very important to detect. Here, we present the photo-acoustic spectroscopy as a low-cost, reliable, sensitive and scattering-free tool to measure the spectral position and absorption efficiency of these modes. The investigated samples are hexagonal nanowires with GaAs core; the fabrication by means of lithography-free molecular beam epitaxy provides controllable and uniform dimensions that allow for the excitation of the fundamental resonant mode around 800 nm. We show that the modulation frequency increase leads to the discrimination of the resonant mode absorption from the overall absorption of the substrate. As the experimental data are in great agreement with numerical simulations, the design can be optimized and followed by photo-acoustic characterization for a specific application.

  17. Testing Disk-Wind Models with Quasar CIV 1549Å Associated Absorption Lines

    DEFF Research Database (Denmark)

    Vestergaard, Marianne

    2012-01-01

    Narrow associated C IV 1549Å absorption lines (NALs) with a rest equivalent width EW =3 Å detected in z ˜ 2 radio-loud and radio-quiet quasars, (a) exhibit evidence of an origin in radiatively accelerated gas, and (b) may be closely related to broad absorption line (BAL) outflows. These NALs...... and the few BALs detected in this quasar sample obey key predictions of models of radiatively driven disk-winds in which (1) the local disk luminosity launches the wind, (2) the central UV radiation drives it outwards, and (3) the wind acceleration (i.e., terminal velocity) depends on the strength of the X...

  18. iMS2Flux – a high–throughput processing tool for stable isotope labeled mass spectrometric data used for metabolic flux analysis

    Directory of Open Access Journals (Sweden)

    Poskar C Hart

    2012-11-01

    Full Text Available Abstract Background Metabolic flux analysis has become an established method in systems biology and functional genomics. The most common approach for determining intracellular metabolic fluxes is to utilize mass spectrometry in combination with stable isotope labeling experiments. However, before the mass spectrometric data can be used it has to be corrected for biases caused by naturally occurring stable isotopes, by the analytical technique(s employed, or by the biological sample itself. Finally the MS data and the labeling information it contains have to be assembled into a data format usable by flux analysis software (of which several dedicated packages exist. Currently the processing of mass spectrometric data is time-consuming and error-prone requiring peak by peak cut-and-paste analysis and manual curation. In order to facilitate high-throughput metabolic flux analysis, the automation of multiple steps in the analytical workflow is necessary. Results Here we describe iMS2Flux, software developed to automate, standardize and connect the data flow between mass spectrometric measurements and flux analysis programs. This tool streamlines the transfer of data from extraction via correction tools to 13C-Flux software by processing MS data from stable isotope labeling experiments. It allows the correction of large and heterogeneous MS datasets for the presence of naturally occurring stable isotopes, initial biomass and several mass spectrometry effects. Before and after data correction, several checks can be performed to ensure accurate data. The corrected data may be returned in a variety of formats including those used by metabolic flux analysis software such as 13CFLUX, OpenFLUX and 13CFLUX2. Conclusion iMS2Flux is a versatile, easy to use tool for the automated processing of mass spectrometric data containing isotope labeling information. It represents the core framework for a standardized workflow and data processing. Due to its flexibility

  19. Determination of 2-alkylcyclobutanones by combining precolumn derivatization with 1-naphthalenyl hydrazine and ultra-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Meng, Xiangpeng; Tong, Tong; Wang, Lianrong; Liu, Hanxia; Chan, Wan

    2016-05-01

    2-Alkylcyclobutanones (2-ACBs) are uniquely formed when triglycerides-containing food products are exposed to ionizing radiation. Thus, 2-ACBs have been used as marker molecules to identify irradiated food. Most methods to determine 2-ACBs involve mass spectrometric detection after chromatographic separation. The spectrofluorometer is rarely used to determine 2-ACBs because these molecules do not fluoresce. In this study, we developed an ultra-performance liquid chromatography (UPLC) method to determine 2-ACBs. 2-ACBs were converted into fluorophores after reacting with 1-naphthalenyl hydrazine to facilitate their sensitive and selective detection using a fluorescence detector (FLD). Analysis of 2-ACBs using our developed UPLC-FLD method allows sensitive determination of 2-ACBs at a detection limit of 2 ng 2-ACBs per g of fat (30 pg/injection), which is significantly lower than that of existing analytical methods. After validation for trueness and precision, the method was applied to γ-irradiated chicken samples to determine their 2-ACB content. Comparative studies employing liquid chromatography-tandem mass spectrometric method revealed no systematic difference between the two methods, thereby demonstrating that the proposed UPLC-FLD method can be suitably used to determine 2-ACBs in irradiated foodstuffs. Graphical Abstract Determination of radiation-induced food-borne 2-dodecylcyclobutanone and 2-tetradecylcyclobutanone by combining 1-naphthalenyl hydrazine derivatization and ultra-performance liquid chromatography with fluorescence detection.

  20. Development of gallium arsenide gamma spectrometric detector

    International Nuclear Information System (INIS)

    Kobayashi, T.; Kuru, I.

    1975-03-01

    GaAs semiconductor material has been considered to be a suitable material for gamma-ray spectrometer operating at room temperature since it has a wid-band gap, larger than that of silicon and germanium. The basic objective of this work is to develop a GaAs gamma-ray spectrometric detector which could be used for gamma spectrometric measurement of uranium and plutonium in nuclear fuel safeguards. Liquid phase epitaxial techniques using iron (Fe) as dopant have been developed in making high purity GaAs crystals suitable for gamma-ray spectrometer operating at room temperature. Concentration of Fe in the epitaxial crystal was controlled by initial growth temperature. The best quality epitaxial crystal was obtained under the following conditions: starting temperature is about 800degC, the proportion of Fe to Ga solvent is 1 to 300. Carrier concentration of epitaxial crystals grown distributed in the ranges of 10 12 cm -3 to 10 14 cm -3 at room temperature. The thickness of the crystals ranged from 38 μm to 120 μm. Au-GaAs surface barrier detector was made of epitaxial crystal. Some of the detector were encapsulated in a can with a 50 μm Be window by welding a can to the detector holder. The detector with high energy resolution and good charge collecting characteristics was selected by alpha spectrometry at room temperature. Energy resolution of the detector for gamma-rays up to about 200 keV was very good at room temperature operation. The best energy resolutions taken with a GaAs detector were 3 keV (fwhm) and 3.8 keV for 241 Am 59.6 keV and 57 Co 122 keV, respectively, at room temperature. In order to study the applicability of the detector for nuclear safeguards, the measurements of 235 U gamma-ray spectrum have been carried out at room temperature. It was clarified that the gamma-ray spectrum of enriched U sample could be measured in high resolution with GaAs detector at room temperature, and that the content of 235 U in enriched U sources could be determined by

  1. Repetitively Mode-Locked Cavity-Enhanced Absorption Spectroscopy (RML-CEAS for Near-Infrared Gas Sensing

    Directory of Open Access Journals (Sweden)

    Qixin He

    2017-12-01

    Full Text Available A Pound-Drever-Hall (PDH-based mode-locked cavity-enhanced sensor system was developed using a distributed feedback diode laser centered at 1.53 µm as the laser source. Laser temperature scanning, bias control of the piezoelectric ceramic transducer (PZT and proportional-integral-derivative (PID feedback control of diode laser current were used to repetitively lock the laser modes to the cavity modes. A gas absorption spectrum was obtained by using a series of absorption data from the discrete mode-locked points. The 15 cm-long Fabry-Perot cavity was sealed using an enclosure with an inlet and outlet for gas pumping and a PZT for cavity length tuning. The performance of the sensor system was evaluated by conducting water vapor measurements. A linear relationship was observed between the measured absorption signal amplitude and the H2O concentration. A minimum detectable absorption coefficient of 1.5 × 10–8 cm–1 was achieved with an averaging time of 700 s. This technique can also be used for the detection of other trace gas species by targeting the corresponding gas absorption line.

  2. Double wavelength differential absorption as a technique for early diagnosis of breast cancer

    Science.gov (United States)

    Liger, Vladimir V.; Zybin, Alexander V.; Niemax, Kay; Kuritsyn, Yuri A.; Bolshov, Mikhail A.

    2005-08-01

    The double-wavelength differential molecular absorption technique with diode lasers is proposed for sensitive detection of functional status of breast tissues. The method is based on the measurement of the transmitted intensity differences of the two beams of diode lasers tuned to selected wavelengths within a broad absorption band of a human breast tissue within 700 - 800 nm spectral range. The strategy for the optimum selection of the diode laser wavelengths and initial adjustment of the detection scheme is developed. The method is demonstrated by the detection of the relative concentrations of two dyes, the optical properties of which are similar to those of a mixture of oxy- and deoxy- hemoglobin. The results of the first clinical tests of the proposed technique are briefly described.

  3. Derivative flame atomic absorption spectrometry and its application in trace analysis

    International Nuclear Information System (INIS)

    Sun, H. W.; Li, L. Q.

    2005-01-01

    Flame atomic absorption spectrometry is an accepted and widely used method for the determination of trace elements in a great variety of samples. But its sensitivity doesn't meet the demands of trace and ultra-trace analysis for some samples. The derivative signal processing technique, with a very high capability for enhancing sensitivity, was developed for flame atomic absorption spectrometry. The signal models of conventional flame atomic absorption spectrometry are described. The equations of derivative signals are established for flame atomic absorption spectrometry, flow injection atomic absorption spectrometry (FI-FAAS) and atom trapping flame atomic absorption spectrometry (AT-FAAS). The principle and performance of the derivative atomic absorption spectrometry are evaluated. The derivative technique based on determination of variation rate of signal intensity with time (dl/dt) is different from the derivative spectrophotometry based on determination of variation rate of signal intensity with wavelength (dl/dhλ). Derivative flame atomic absorption spectrometry has higher sensitivity, lower detection limits and better accuracy. It has been applied to the direct determination of trace elements without preconcentration. If the derivative technique was combined with several preconcentration techniques, the sensitivity would be enhanced further for ultra-trace analysis with good linearity. The applications of derivative flame atomic absorption spectroscopy are reviewed for trace element analysis in biological, pharmaceutical, environmental and food samples

  4. A laboratory experimental setup for photo-absorption studies using synchrotron radiation

    CERN Document Server

    Shastri, A; Saraswati, P; Sunanda, K

    2002-01-01

    The photophysics beamline, which is being installed at the 450 MeV Synchrotron Radiation Source (SRS), Indus-l, is a medium resolution beamline useful for a variety of experiments in the VUV region viz. 500-2000 A. One of the major applications of this beamline is gas-phase photo-absorption studies. An experimental set up to be used for these experiments was designed, developed and tested in our laboratory. The setup consists of a high vacuum absorption cell, 1/4 m monochromator and detection system. For the purpose of testing, xenon and tungsten continuum sources were used and absorption spectra were recorded in the UV region. This setup was used to record the absorption spectrum of a few molecules like acetone, ammonia, benzene, formaldehyde and acetaldehyde in order to evaluate the performance of the experimental system which will subsequently be used with the photophysics beamline. Details of the design, fabrication and testing of the absorption cell and experimental procedures are presented in this repor...

  5. Resolution of a protein sequence ambiguity by X-ray crystallographic and mass spectrometric methods

    International Nuclear Information System (INIS)

    Keefe, L.J.; Lattman, E.E.; Wolkow, C.; Woods, A.; Chevrier, M.; Cotter, R.J.

    1992-01-01

    Ambiguities in amino acid sequences are a potential problem in X-ray crystallographic studies of proteins. Amino acid side chains often cannot be reliably identified from the electron density. Many protein crystal structures that are now being solved are simple variants of a known wild-type structure. Thus, cloning artifacts or other untoward events can readily lead to cases in which the proposed sequence is not correct. An example is presented showing that mass spectrometry provides an excellent tool for analyzing suspected errors. The X-ray crystal structure of an insertion mutant of Staphylococcal nuclease has been solved to 1.67 A resolution and refined to a crystallographic R value of 0.170. A single residue has been inserted in the C-terminal α helix. The inserted amino acid was believed to be an alanine residue, but the final electron density maps strongly indicated that a glycine had been inserted instead. To confirm the observations from the X-ray data, matrix-assisted laser desorption mass spectrometry was employed to verify the glycine insertion. This mass spectrometric technique has sufficient mass accuracy to detect the methyl group that distinguishes glycine from alanine and can be extended to the more common situation in which crystallographic measurements suggest a problem with the sequence, but cannot pinpoint its location or nature. (orig.)

  6. Resolution of a protein sequence ambiguity by X-ray crystallographic and mass spectrometric methods

    Energy Technology Data Exchange (ETDEWEB)

    Keefe, L.J.; Lattman, E.E. (Dept. of Biophysics and Biophysical Chemistry, Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States)); Wolkow, C.; Woods, A.; Chevrier, M.; Cotter, R.J. (Middle Atlantic Mass Spectrometry Lab., Johns Hopkins Univ. School of Medicine, Baltimore, MD (United States))

    1992-04-01

    Ambiguities in amino acid sequences are a potential problem in X-ray crystallographic studies of proteins. Amino acid side chains often cannot be reliably identified from the electron density. Many protein crystal structures that are now being solved are simple variants of a known wild-type structure. Thus, cloning artifacts or other untoward events can readily lead to cases in which the proposed sequence is not correct. An example is presented showing that mass spectrometry provides an excellent tool for analyzing suspected errors. The X-ray crystal structure of an insertion mutant of Staphylococcal nuclease has been solved to 1.67 A resolution and refined to a crystallographic R value of 0.170. A single residue has been inserted in the C-terminal {alpha} helix. The inserted amino acid was believed to be an alanine residue, but the final electron density maps strongly indicated that a glycine had been inserted instead. To confirm the observations from the X-ray data, matrix-assisted laser desorption mass spectrometry was employed to verify the glycine insertion. This mass spectrometric technique has sufficient mass accuracy to detect the methyl group that distinguishes glycine from alanine and can be extended to the more common situation in which crystallographic measurements suggest a problem with the sequence, but cannot pinpoint its location or nature. (orig.).

  7. Evaluation of radioactive environmental hazards in Area-3, Northern Palmyrides, Central Syria using airborne spectrometric gamma technique

    International Nuclear Information System (INIS)

    Asfahani, J.; Aissa, M.; Al-Hent, R.

    2016-01-01

    Airborne spectrometric gamma data are used in this paper to estimate the degree of radioactive hazard on humanity in Area-3, Northern Palmyrides, Central Syria. Exposure Rate (ER), Absorbed Dose Rate (ADR), Annual Effective Dose Rate (AEDR), and Heat Production (HP) of the eleven radiometric units included in the established lithological scored map in the study area have been computed to evaluate the radiation background influence in humans. The results obtained indicate that a human body in Area-3 is subjected to radiation hazards in the acceptable limits for long duration exposure. The highest radiogenetic heat production values in Area-3 correspond to the phosphatic locations characterized by relatively high values of uranium and thorium. - Highlights: • Degree of radioactive hazard has been estimated by using airborne spectrometric gamma data. • ER, ADR, AEDR, and HP of the eleven radiometric units have been computed. • Comparison of AEDR of Area-3 with the AEDR of Area-1. • Human body in Area-3 is subjected to radiation hazards in the acceptable limits for long duration exposure. • The highest heat production in Area-3 correspond to the phosphatic locations.

  8. Reply to "On Vaporization of liquid Pb-Li eutectic alloy from 1000 K to 1200 K- A high temperature mass spectrometric study"

    Science.gov (United States)

    Jain, Uttam; Mukherjee, Abhishek

    2018-03-01

    This communication is in response to a letter to editor commenting on the authors' earlier paper "Vaporization of liquid Pb-Li eutectic alloy from 1000 K to 1200 K - A high temperature mass spectrometric study".

  9. Detection limits for radioanalytical counting techniques

    International Nuclear Information System (INIS)

    Hartwell, J.K.

    1975-06-01

    In low-level radioanalysis it is usually necessary to test the sample net counts against some ''Critical Level'' in order to determine if a given result indicates detection. This is an interpretive review of the work by Nicholson (1963), Currie (1968) and Gilbert (1974). Nicholson's evaluation of three different computational formulas for estimation of the ''Critical Level'' is discussed. The details of Nicholson's evaluation are presented along with a basic discussion of the testing procedures used. Recommendations are presented for calculation of confidence intervals, for reporting of analytical results, and for extension of the derived formula to more complex cases such as multiple background counts, multiple use of a single background count, and gamma spectrometric analysis

  10. Selection of the optimal combination of water vapor absorption lines for detection of temperature in combustion zones of mixing supersonic gas flows by diode laser absorption spectrometry

    International Nuclear Information System (INIS)

    Mironenko, V.R.; Kuritsyn, Yu.A.; Bolshov, M.A.; Liger, V.V.

    2017-01-01

    Determination of a gas medium temperature by diode laser absorption spectrometry (DLAS) is based on the measurement of integral intensities of the absorption lines of a test molecule (generally water vapor molecule). In case of local thermodynamic equilibrium temperature is inferred from the ratio of the integral intensities of two lines with different low energy levels. For the total gas pressure above 1 atm the absorption lines are broadened and one cannot find isolated well resolved water vapor absorption lines within relatively narrow spectral interval of fast diode laser (DL) tuning range (about 3 cm"−"1). For diagnostics of a gas object in the case of high temperature and pressure DLAS technique can be realized with two diode lasers working in different spectral regions with strong absorption lines. In such situation the criteria of the optimal line selection differs significantly from the case of narrow lines. These criteria are discussed in our work. The software for selection the optimal spectral regions using the HITRAN-2012 and HITEMP data bases is developed. The program selects spectral regions of DL tuning, minimizing the error of temperature determination δT/T, basing on the attainable experimental error of line intensity measurement δS. Two combinations of optimal spectral regions were selected – (1.392 & 1.343 μm) and (1.392 & 1.339 μm). Different algorithms of experimental data processing are discussed.

  11. Characterisation of radioactive contaminated materials by combined radiometric and spectrometric methods

    International Nuclear Information System (INIS)

    Dulama, C.; Toma, A.; Dobrin, R.; Ciocîrlan, C.; Stoica, S.; Valeca, M.; Popescu, I. I.

    2013-01-01

    In the present paper, a combined analytical methodology is described, for characterization of radioactive contaminated materials. The subject of testing activities was a set of solutions provided by the Cernavoda NPP, which are originating from processes of radiological survey of workplaces in the plant. In the introduction section, a theoretical approach was given to the origin and nature of main radionuclides occurring in the primary cooling system of the nuclear power plant, with the aim to establish selection criteria and performance requirements for the analytical methods to be used in the development of the characterization methodology. A combination of radiometric and spectrometric methods was selected, based on gross beta counting, high resolution gamma-ray spectrometry and liquid scintillation counting. (authors)

  12. Liquid chromatography-tandem mass spectrometric assay for the tyrosine kinase inhibitor afatinib in mouse plasma using salting-out liquid-liquid extraction

    NARCIS (Netherlands)

    Sparidans, Rolf W; van Hoppe, Stephanie; Rood, Johannes J M; Schinkel, Alfred H; Schellens, Jan H M; Beijnen, Jos H

    2016-01-01

    A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for afatinib, an irreversible inhibitor of the ErbB (erythroblastic leukemia viral oncogene homolog) tyrosine kinase family, was developed and validated. Plasma samples were pre-treated using salting-out

  13. Laser absorption spectroscopy - Method for monitoring complex trace gas mixtures

    Science.gov (United States)

    Green, B. D.; Steinfeld, J. I.

    1976-01-01

    A frequency stabilized CO2 laser was used for accurate determinations of the absorption coefficients of various gases in the wavelength region from 9 to 11 microns. The gases investigated were representative of the types of contaminants expected to build up in recycled atmospheres. These absorption coefficients were then used in determining the presence and amount of the gases in prepared mixtures. The effect of interferences on the minimum detectable concentration of the gases was measured. The accuracies of various methods of solution were also evaluated.

  14. Simultaneous multi-element atomic absorption system using photodiode array detector

    International Nuclear Information System (INIS)

    Tong, S.L.; Chin, K.S.

    1994-01-01

    A photodiode array (PDA) detector-multichannel analyser (MCA) system has been coupled to a flame and a graphite furnace atomiser and tested for simultaneous multielement atomic absorption analysis. Multielement hollow cathode lamps (HCL) are used as light source. Spectral lines are dispersed through a spectrograph with triple gratings and detected by a 25.4 mm PDA detector consisting of 1024 elements. The optical MCA system is capable of recording multiple spectra spanned by the spectrograph/PDA. The transmitted intensity spectra obtained for the standard and analyte solutions during flame or graphite furnace atomisation are converted to absorbance spectra using the MCA software provided. Results from the comparison studies show that the linear range and sensitivities for Ni-Co-Fe and Cu-Cr obtained from the simultaneous measurements are within the same order of magnitudes as those from conventional single element determinations using photomultiplier tube detection. The study also shows that non-atomic absorption can be readily corrected by a two-line method where non-atomic absorption lines can be chosen from the spectra recorded simultaneously. The proposed system has been evaluated for the determination of trace elements using NBS standard reference water SRM 1643b

  15. Functional proteomics with new mass spectrometric and bioinformatics tools

    International Nuclear Information System (INIS)

    Kesners, P.W.A.

    2001-01-01

    A comprehensive range of mass spectrometric tools is required to investigate todays life science applications and a strong focus is on addressing the needs of functional proteomics. Application examples are given showing the streamlined process of protein identification from low femtomole amounts of digests. Sample preparation is achieved with a convertible robot for automated 2D gel picking, and MALDI target dispensing. MALDI-TOF or ESI-MS subsequent to enzymatic digestion. A choice of mass spectrometers including Q-q-TOF with multipass capability, MALDI-MS/MS with unsegmented PSD, Ion Trap and FT-MS are discussed for their respective strengths and applications. Bioinformatics software that allows both database work and novel peptide mass spectra interpretation is reviewed. The automated database searching uses either entire digest LC-MS n ESI Ion Trap data or MALDI MS and MS/MS spectra. It is shown how post translational modifications are interactively uncovered and de-novo sequencing of peptides is facilitated

  16. Extreme Variability in a Broad Absorption Line Quasar

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Daniel; Jun, Hyunsung D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-221, Pasadena, CA 91109 (United States); Graham, Matthew J.; Djorgovski, S. G.; Donalek, Ciro; Drake, Andrew J.; Mahabal, Ashish A.; Steidel, Charles C. [California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Arav, Nahum; Chamberlain, Carter [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Barth, Aaron J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Glikman, Eilat, E-mail: daniel.k.stern@jpl.nasa.gov [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States)

    2017-04-20

    CRTS J084133.15+200525.8 is an optically bright quasar at z = 2.345 that has shown extreme spectral variability over the past decade. Photometrically, the source had a visual magnitude of V ∼ 17.3 between 2002 and 2008. Then, over the following five years, the source slowly brightened by approximately one magnitude, to V ∼ 16.2. Only ∼1 in 10,000 quasars show such extreme variability, as quantified by the extreme parameters derived for this quasar assuming a damped random walk model. A combination of archival and newly acquired spectra reveal the source to be an iron low-ionization broad absorption line quasar with extreme changes in its absorption spectrum. Some absorption features completely disappear over the 9 years of optical spectra, while other features remain essentially unchanged. We report the first definitive redshift for this source, based on the detection of broad H α in a Keck/MOSFIRE spectrum. Absorption systems separated by several 1000 km s{sup −1} in velocity show coordinated weakening in the depths of their troughs as the continuum flux increases. We interpret the broad absorption line variability to be due to changes in photoionization, rather than due to motion of material along our line of sight. This source highlights one sort of rare transition object that astronomy will now be finding through dedicated time-domain surveys.

  17. Mass spectrometric study of vaporization of cesium tellurate and tellurite

    International Nuclear Information System (INIS)

    Semenov, G.A.; Fokina, L.A.; Mouldagalieva, R.A.

    1994-01-01

    The process of vaporization of cesium tellurate and tellurite was studied by the Knudsen effusion method with a mass spectrometric analysis of the vapor composition. The thermal dissociation of Cs 2 TeO 4 to Cs 2 TeO 3 and the congruent vaporization of Cs 2 TeO 3 were established. Thermodynamic functions for gaseous Cs 2 TeO 3 have been calculated. The standard enthalpy of sublimation Δ s H (298.15)=268.1±13.0 kJ mol -1 was determined by the 2nd and 3rd laws of thermodynamics. The enthalpy of formation Δ f H (298.15)=-725.1±13.0 kJ mol -1 for gaseous Cs 2 TeO 3 and the enthalpy of atomization Δ at H (298.15)=1841.3±15.0 kJ mol -1 have been computed. ((orig.))

  18. Electrochemical and Infrared Absorption Spectroscopy Detection of SF₆ Decomposition Products.

    Science.gov (United States)

    Dong, Ming; Zhang, Chongxing; Ren, Ming; Albarracín, Ricardo; Ye, Rixin

    2017-11-15

    Sulfur hexafluoride (SF₆) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF₆ decomposition and ultimately generates several types of decomposition products. These SF₆ decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF₆ decomposition products, and electrochemical sensing (ES) and infrared (IR) spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF₆ gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF₆ decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF₆ gas decomposition and is verified to reliably and accurately detect the gas components and concentrations.

  19. Terverticillate Penicillia studied by direct electrospray mass spectrometric profiling of crude extracts: I. Chemosystematics

    DEFF Research Database (Denmark)

    Smedsgaard, Jørn; Frisvad, Jens Christian

    1997-01-01

    ) and Yeast Extract Sucrose agar (YES) directly into the electrospray source of the mass spectrometer. A data matrix was made from each substrate by transferring the complete centroid mass spectrum from 200 to 700 amu as 501 variables to individual columns. No attempt was made to identify ions in the mass......A chemosystematic study of 339 isolates from all known terverticillate Penicillium taxa was performed using electrospray mass spectrometric analysis of extractable metabolites. The mass profiles were made by injecting crude plug extracts made from cultures grown on Czapek Yeast Autolysate agar (CYA...

  20. Certification of model spectrometric alpha sources (MSAS) and problems of the MSAS system improvement

    International Nuclear Information System (INIS)

    Belyatskij, A.F.; Gejdel'man, A.M.; Egorov, Yu.S.; Nedovesov, V.G.; Chechev, V.P.

    1984-01-01

    Results of certification of standard spectrometric alpha sources (SSAS) of industrial production are presented: methods for certification by main radiation physical parameters: proper halfwidth of α-lines, activity of radionuclides in the source, energies of α-particle emitting sources and relative intensity of different energy α-particle groups - are analysed. The advantage for the SSAS system improvement - a set of model measures for α-radiation, a collection of interconnected data units on physical, engineering and design characteristics of SSAS, methods for their obtaining and determination, on instruments used, is considered

  1. Detection of urinary creatinine using gold nanoparticles after solid phase extraction

    Science.gov (United States)

    Sittiwong, Jarinya; Unob, Fuangfa

    2015-03-01

    Label-free gold nanoparticles (AuNPs) were utilized in the detection of creatinine in human urine after a sample preparation by extraction of creatinine on sulfonic acid functionalized silica gel. With the proposed sample preparation method, the interfering effects of the urine matrix on creatinine detection by AuNPs were eliminated. Parameters affecting creatinine extraction were investigated. The aggregation of AuNPs induced by creatinine resulted in a change in the surface plasmon resonance signal with a concomitant color change that could be observed by the naked eye and quantified spectrometrically. The effect of AuNP concentration and reaction time on AuNP aggregation was investigated. The method described herein provides a determination of creatinine in a range of 15-40 mg L-1 with a detection limit of 13.7 mg L-1 and it was successfully used in the detection of creatinine in human urine samples.

  2. Detection of shock-heated hydrogen peroxide (H2O2) by off-axis cavity-enhanced absorption spectroscopy (OA-CEAS)

    KAUST Repository

    Alquaity, Awad

    2017-11-11

    Cavity-enhanced absorption spectroscopy (CEAS) is a promising technique for studying chemical reactions due to its desirable characteristics of high sensitivity and fast time-response by virtue of the increased path length and relatively short photon residence time inside the cavity. Off-axis CEAS (OA-CEAS) is particularly suited for the shock tube applications as it is insensitive to slight misalignments, and cavity noise is suppressed due to non-overlapping multiple reflections of the probe beam inside the cavity. Here, OA-CEAS is demonstrated in the mid-IR region at 1310.068 cm−1 to monitor trace concentrations of hydrogen peroxide (H2O2). This particular probe frequency was chosen to minimize interference from other species prevalent in combustion systems and in the atmosphere. The noise-equivalent detection limit is found to be 3.25 × 10−5 cm−1, and the gain factor of the cavity is 131. This corresponds to a detection limit of 74 ppm of H2O2 at typical high-temperature combustion conditions (1200 K and 1 atm) and 12 ppm of H2O2 at ambient conditions (296 K and 1 atm). To our knowledge, this is the first successful application of the OA-CEAS technique to detect H2O2 which is vital species in combustion and atmospheric science.

  3. Detection of shock-heated hydrogen peroxide (H2O2) by off-axis cavity-enhanced absorption spectroscopy (OA-CEAS)

    KAUST Repository

    Alquaity, Awad; KC, Utsav; Popov, Alber; Farooq, Aamir

    2017-01-01

    Cavity-enhanced absorption spectroscopy (CEAS) is a promising technique for studying chemical reactions due to its desirable characteristics of high sensitivity and fast time-response by virtue of the increased path length and relatively short photon residence time inside the cavity. Off-axis CEAS (OA-CEAS) is particularly suited for the shock tube applications as it is insensitive to slight misalignments, and cavity noise is suppressed due to non-overlapping multiple reflections of the probe beam inside the cavity. Here, OA-CEAS is demonstrated in the mid-IR region at 1310.068 cm−1 to monitor trace concentrations of hydrogen peroxide (H2O2). This particular probe frequency was chosen to minimize interference from other species prevalent in combustion systems and in the atmosphere. The noise-equivalent detection limit is found to be 3.25 × 10−5 cm−1, and the gain factor of the cavity is 131. This corresponds to a detection limit of 74 ppm of H2O2 at typical high-temperature combustion conditions (1200 K and 1 atm) and 12 ppm of H2O2 at ambient conditions (296 K and 1 atm). To our knowledge, this is the first successful application of the OA-CEAS technique to detect H2O2 which is vital species in combustion and atmospheric science.

  4. Status and application of α-spectrometric 230Th/234U dating of fossil corals in Ryukyus, Japan and the Philippines

    International Nuclear Information System (INIS)

    Inagaki, Miyuki; Omura, Akio; Sasaki, Keiichi

    2007-01-01

    High-precision α-spectrometric 230 Th/ 234 U dating was achieved by recent improvements of measurement system and chemical procedures and enabled critical evaluation of age reliability. We review the status and application of α-spectrometric 230 Th/ 234 U dating of Pleistocene and Holocene corals to reconstruct past sea level changes and tectonic movements in Ryukyus, southwestern Japan and the Philippines in the western rim of circum-Pacific island arcs. The highest terrace in Kikai Island was formed during MIS 5c not MIS 5e that previously reported. Coral reef sediments deposited not only during MIS 5e but also during glacial periods, e.g. MIS 6 and 2, have been found in the Ryukyus. Coral reef sediments formed during MIS 2 were found at ca. 120 m below present sea level off Irabu Island located at 25degN. In addition, it was clear that three terraces developed during MIS 5e, 5c and 5a at Pamilacan Island on the Philippines. (author)

  5. Measurement of Absorption Coefficient of Paraformaldehyde and Metaldehyde with Terahertz Spectroscopy

    Science.gov (United States)

    Zhang, J.; Xia, T.; Chen, Q.; Sun, Q.; Deng, Y.; Wang, C.

    2018-03-01

    The characteristic absorption spectra of paraformaldehyde and metaldehyde in the terahertz frequency region are obtained by terahertz time-domain spectroscopy (THz-TDS). In order to reduce the absorption of terahertz (THz) wave by water vapor in the air and the background noise, the measurement system was filled with dry air and the measurements were conducted at the temperature of 24°C. Meanwhile, the humidity was controlled within 10% RH. The THz frequency domain spectra of samples and their references from 0 to 2.5 THz were analyzed via Fourier transform. The refractive index and absorption coefficients of the two aldehydes were calculated by the model formulas. From 0.1 to 2.5 THz, there appear two weak absorption peaks at 1.20 and 1.66 THz in the absorption spectra of paraformaldehyde. Only one distinct absorption peak emerges at 1.83 THz for metaldehyde. There are significant differences between the terahertz absorption coefficients of paraformaldehyde and metaldehyde, which can be used as "fingerprints" to identify these substances. Furthermore, the relationship between the average absorption coefficients and mass concentrations was investigated and the average absorption coefficient-mass concentration diagrams of paraformaldehyde and metaldehyde were shown. For paraformaldehyde, there is a linear relationship between the average absorption coefficient and the natural logarithm of mass concentration. For metaldehyde, there exists a simpler linear relationship between the average absorption coefficient and the mass concentration. Because of the characteristics of THz absorption of paraformaldehyde and metaldehyde, the THz-TDS can be applied to the qualitative and quantitative detection of the two aldehydes to reduce the unpredictable hazards due to these substances.

  6. A method for exploring the distribution of radioelements at depth using gamma-ray spectrometric data

    International Nuclear Information System (INIS)

    Li Qingyang

    1997-01-01

    Based on the inherent relation between radioelements and terrestrial heat flow, theoretically shows the possibility of exploring the distribution of radioelements at depth using gamma-ray spectrometric data, and a data-processing and synthesizing method has been adopted to deduce the calculation formula. The practical application in the uranium mineralized area No. 2801 in Yunnan Province proves that this method is of practical value, and it has been successfully applied to the data processing and good results have been obtained

  7. Narrow absorption lines with two observations from the Sloan Digital Sky Survey

    Science.gov (United States)

    Chen, Zhi-Fu; Gu, Qiu-Sheng; Chen, Yan-Mei; Cao, Yue

    2015-07-01

    We assemble 3524 quasars from the Sloan Digital Sky Survey (SDSS) with repeated observations to search for variations of the narrow C IV λ λ 1548,1551 and Mg II λ λ 2796,2803 absorption doublets in spectral regions shortward of 7000 Å in the observed frame, which corresponds to time-scales of about 150-2643 d in the quasar rest frame. In these quasar spectra, we detect 3580 C IV absorption systems with zabs = 1.5188-3.5212 and 1809 Mg II absorption systems with zabs = 0.3948-1.7167. In term of the absorber velocity (β) distribution in the quasar rest frame, we find a substantial number of C IV absorbers with β Hacker et al. However, in our Mg II absorption sample, we find that neither shows variable absorption with confident levels of >4σ for λ2796 lines and >3σ for λ2803 lines.

  8. PG 1700 + 518 - a low-redshift, broad absorption line QSO

    International Nuclear Information System (INIS)

    Pettini, M.; Boksenberg, A.

    1985-01-01

    The first high-resolution optical spectra and lower resolution UV spectra of PG 1700 + 518, the only known broad-absorption-line (BAL) QSO at low emission redshift (0.288) are presented. The optical data were obtained with the Isaac Newton Telescope on the island of La Palma and the UV data with the International Ultraviolet Explorer satellite. The outstanding feature of the optical spectrum is a strong, broad Mg II absorption trough, detached from the Mg II emission line and indicative of ejection velocities of between 7000 and 18,000 km/s. Also detected were narrow (FWHM = 350 km/s) Mg II absorption lines at absolute z = 0.2698, which are probably related to the mass ejection phenomenon. It is concluded that the emission-line spectrum is similar to that of other low-redshift QSOs although there are some obvious differences from typical BAL QSOs, most notably in the unusually low level of ionization of both emission-line and broad absorption line gas. 21 references

  9. Trace gas absorption spectroscopy using laser difference-frequency spectrometer for environmental application

    Science.gov (United States)

    Chen, W.; Cazier, F.; Boucher, D.; Tittel, F. K.; Davies, P. B.

    2001-01-01

    A widely tunable infrared spectrometer based on difference frequency generation (DFG) has been developed for organic trace gas detection by laser absorption spectroscopy. On-line measurements of concentration of various hydrocarbons, such as acetylene, benzene, and ethylene, were investigated using high-resolution DFG trace gas spectroscopy for highly sensitive detection.

  10. A liquid-He cryostat for structural and thermal disorder studies by X-ray absorption.

    Science.gov (United States)

    Bouamrane, F; Ribbens, M; Fonda, E; Adjouri, C; Traverse, A

    2003-07-01

    A new device operating from 4.2 to 300 K is now installed on the hard X-ray station of the DCI ring in LURE in order to measure absorption coefficients. This liquid-He bath device has three optical windows. One allows the incident beam to impinge on the sample, one located at 180 degrees with respect to the sample allows transmitted beams to be detected, and another located at 90 degrees is used to detect emitted photons. Total electron yield detection mode is also possible thanks to a specific sample holder equipped with an electrode that collects the charges created by the emitted electrons in the He gas brought from the He bath around the sample. The performance of the cryostat is described by measurements of the absorption coefficients versus the temperature for Cu and Co foils. For comparison, the absorption coefficient is also measured for Cu clusters. As expected from dimension effects, the Debye temperature obtained for the clusters is lower than that of bulk Cu.

  11. Development of spectrometric probes for emergency preparedness. Status and way forward; Entwicklung von spektrometrierenden Sonden fuer den Notfallschutz. Stand und Perspektiven

    Energy Technology Data Exchange (ETDEWEB)

    Zaehringer, M.; Bleher, M. [Bundesamt fuer Strahlenschutz (BfS), Salzgitter (Germany); Dambacher, M. [X-Ray Imaging Europe, Freiburg (Germany); and others

    2014-01-20

    Spectrometric probes with medium energy resolution (NaI, LaBr{sub 3}, CZT) have the potential to enhance existing gamma dose rate monitoring networks as a early warning system by increasing the sensitivity and specificity. In an emergency situation nuclide specific information with sufficient spatial resolution can be made available to decision makers. An ongoing research project between BfS and the Freiburg Material Research Centre (FMF) aims at the development of semiconductor detectors based on Cadmium-Zink-Telluride which can be used for low cost ruggedized spectrometric systems suitable for deployment in an environmental network. The new probe contains also a newly developed versatile multi channel analyser. The system has a modular design and is based - where ever possible - on open source components. It is complemented by specific analysis software using established data exchange formats. This facilitates international cooperation and exploits synergies through distributed development of components.

  12. INTERLABORATORY STUDY OF A THERMOSPRAY-LIQUID CHROMATOGRAPHIC/MASS SPECTROMETRIC METHOD FOR SELECTED N-METHYL CARBAMATES, N-METHYL CARBAMOYLOXIMES, AND SUBSTITUTED UREA PESTICIDES

    Science.gov (United States)

    A thermospray-liquid chromatographic/mass spectrometric (TS-LC/MS) method was evaluated in an interlaboratory study for determining 3 N-methyl carbamates (bendiocarb, carbaryl, and carbofuran), 3-N-methyl carbamoyloximes (aldicarb, methomyl, and oxamyl), 2 substituted urea pestic...

  13. Continuous registration of optical absorption spectra of periodically produced solvated electrons

    International Nuclear Information System (INIS)

    Krebs, P.

    1975-01-01

    Absorption spectra of unstable intermediates, such as solvated electrons, were usually taken point by point, recording the time-dependent light absorption after their production by a flash. The experimental arrangement for continuous recording of the spectra consists of a conventional one beam spectral photometer with a stabilized white light source, a monochromator, and a light detector. By periodic production of light absorbing intermediates such as solvated electrons, e.g., by ac uv light, a small ac signal is modulated on the light detector output which after amplification can be continuously recorded as a function of wavelength. This method allows the detection of absorption spectra when disturbances from the outside provide a signal-to-noise ratio smaller than 1

  14. Tunneling times in bianisotropic, dispersive and absorptive metamaterials

    International Nuclear Information System (INIS)

    Radosavljević, Sanja; Radovanović, Jelena; Milanović, Vitomir

    2016-01-01

    Tunneling times in complex bianisotropic materials have been examined in detail, with absorption and dispersion taken into account. Tunneling is characterized by the dwell and the phase tunneling time. In this paper, we have developed a theoretical model and derived the appropriate expressions for each of these quantities, as well as a relationship between them and the corresponding expression for the energy density. The model has been verified through numerical calculations based on experimental data. We have distinguished cases in which the phases of transmitted and incident wave match each other, and showed that for small angles of incidence, the time that the wave spends inside the barrier can be approximated as a linear function of the barrier width. The Hartman effect has been detected, although for very thick layers of metamaterial. - Highlights: • We analyze the tunneling times in bianisotropic, dispersive and absorptive metamaterials. • Conditions of zero phase tunneling time are identified for a range of frequencies of interest. • The Hartman effect has been detected for very thick barriers of metamaterial.

  15. Tunneling times in bianisotropic, dispersive and absorptive metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Radosavljević, Sanja [School of Electrical Engineering, University of Belgrade, Bulevar kralja Aleksandra 73, 11120 Belgrade (Serbia); Photonics Research Group, Ghent University – imec, Sint-Pietersnieuwstraat 41, 9000 Ghent (Belgium); Radovanović, Jelena, E-mail: radovanovic@etf.bg.ac.rs [School of Electrical Engineering, University of Belgrade, Bulevar kralja Aleksandra 73, 11120 Belgrade (Serbia); Milanović, Vitomir [School of Electrical Engineering, University of Belgrade, Bulevar kralja Aleksandra 73, 11120 Belgrade (Serbia)

    2016-12-09

    Tunneling times in complex bianisotropic materials have been examined in detail, with absorption and dispersion taken into account. Tunneling is characterized by the dwell and the phase tunneling time. In this paper, we have developed a theoretical model and derived the appropriate expressions for each of these quantities, as well as a relationship between them and the corresponding expression for the energy density. The model has been verified through numerical calculations based on experimental data. We have distinguished cases in which the phases of transmitted and incident wave match each other, and showed that for small angles of incidence, the time that the wave spends inside the barrier can be approximated as a linear function of the barrier width. The Hartman effect has been detected, although for very thick layers of metamaterial. - Highlights: • We analyze the tunneling times in bianisotropic, dispersive and absorptive metamaterials. • Conditions of zero phase tunneling time are identified for a range of frequencies of interest. • The Hartman effect has been detected for very thick barriers of metamaterial.

  16. NEW PERSPECTIVE ON GALAXY OUTFLOWS FROM THE FIRST DETECTION OF BOTH INTRINSIC AND TRAVERSE METAL-LINE ABSORPTION

    Energy Technology Data Exchange (ETDEWEB)

    Kacprzak, Glenn G.; Cooke, Jeff [Swinburne University of Technology, Victoria 3122 (Australia); Martin, Crystal L.; Ho, Stephanie H. [Physics Department, University of California, Santa Barbara, CA 93106 (United States); Bouché, Nicolas; LeReun, Audrey; Schroetter, Ilane [CNRS, Institut de Recherche en Astrophysique et Planétologie (IRAP) de Toulouse, 14 Avenue E. Belin, F-31400 Toulouse (France); Churchill, Christopher W.; Klimek, Elizabeth, E-mail: gkacprzak@astro.swin.edu.au [New Mexico State University, Las Cruces, NM 88003 (United States)

    2014-09-01

    We present the first observation of a galaxy (z = 0.2) that exhibits metal-line absorption back-illuminated by the galaxy (down-the-barrel) and transversely by a background quasar at a projected distance of 58 kpc. Both absorption systems, traced by Mg II, are blueshifted relative to the galaxy systemic velocity. The quasar sight line, which resides almost directly along the projected minor axis of the galaxy, probes Mg I and Mg II absorption obtained from the Keck/Low Resolution Imaging Spectrometer as well as Lyα, Si II, and Si III absorption obtained from the Hubble Space Telescope/Cosmic Origins Spectrograph. For the first time, we combine two independent models used to quantify the outflow properties for down-the-barrel and transverse absorption. We find that the modeled down-the-barrel deprojected outflow velocities range between V {sub dtb} = 45-255 km s{sup –1}. The transverse bi-conical outflow model, assuming constant-velocity flows perpendicular to the disk, requires wind velocities V {sub outflow} = 40-80 km s{sup –1} to reproduce the transverse Mg II absorption kinematics, which is consistent with the range of V {sub dtb}. The galaxy has a metallicity, derived from Hα and N II, of [O/H] = –0.21 ± 0.08, whereas the transverse absorption has [X/H] = –1.12 ± 0.02. The galaxy star formation rate is constrained between 4.6-15 M {sub ☉} yr{sup –1} while the estimated outflow rate ranges between 1.6-4.2 M {sub ☉} yr{sup –1} and yields a wind loading factor ranging between 0.1-0.9. The galaxy and gas metallicities, the galaxy-quasar sight-line geometry, and the down-the-barrel and transverse modeled outflow velocities collectively suggest that the transverse gas originates from ongoing outflowing material from the galaxy. The ∼1 dex decrease in metallicity from the base of the outflow to the outer halo suggests metal dilution of the gas by the time it reached 58 kpc.

  17. Carbon dioxide laser absorption spectra of toxic industrial compounds

    International Nuclear Information System (INIS)

    Loper, G.L.; Sasaki, G.R.; Stamps, M.A.

    1982-01-01

    CO 2 laser absorption cross-section data are reported for acrolein, styrene, ethyl acrylate, trichloroethylene, vinyl bromide, and vinylidene chloride. These data indicate that sub parts per billion level, interference-free detection limits should be possible for these compounds by the CO 2 laser photoacoustic technique. Photoacoustic detectabilities below 40 ppb should be possible for these compounds in the presence of ambient air concentrations of water vapor and other anticipated interferences. These compounds are also found not to be important inerference in the detection of toxic hydrazine-based rocket fuels by CO 2 laser spectroscopic techniques

  18. Knudsen cell mass spectrometric study of the Cs2IOH(g) molecule thermodynamics

    International Nuclear Information System (INIS)

    Roki, F-Z.; Ohnet, M-N.; Fillet, S.; Chatillon, C.; Nuta, I.

    2013-01-01

    Highlights: • The pronounced ionic character leads to only dissociative ionization processes. • Ions formed are same as those coming from pure dimmers. • De-convolution of the ions origin needs accurate thermodynamic values for the pure gas phase. • Mass spectrometric interpretation has to be performed gradually and as a function of suitable condensed compositions. • Thermal functions have to be fully estimated. -- Abstract: The gas phase of the CsI + CsOH system is analyzed by high temperature Knudsen cell mass spectrometry in order to confirm the existence of the Cs 2 IOH(g) complex molecule. The mass spectrometric analysis is quite complex since such molecules undergo dissociative ionization into fragment ions that mix with the same ions from dimers of the pure compounds in the same vapor phase. Varying the chemical conditions for vaporization by using different CsI + CsOH mixture contents showed that the ionization of the Cs 2 IOH(g) molecule led to five different fragment ions, Cs 2 OH + , Cs 2 I + , Cs + , CsOH + and CsI + . This complex ionization pattern was studied in relation with previous assessed values for the vaporization of CsOH and CsI pure compounds in which monomer and dimer molecules are predominant. The equilibrium constant for the reaction CsI(g) + CsOH(g) = Cs 2 IOH(g) was determined and, after modeling the structure of the Cs 2 IOH molecule, the enthalpy of formation was determined using the third law of thermodynamics, as follows: Δ f H°(Cs 2 IOH, g, 298.15 K) = −578 ± 14.7 kJ · mole −1

  19. Characterization of organic and conventional sweet basil leaves using chromatographic and flow-injection mass spectrometric (FIMS) fingerprints combined with principal component analysis

    Science.gov (United States)

    Lu, Yingjian; Gao, Boyan; Chen, Pei; Charles, Denys; Yu, Liangli (Lucy)

    2014-01-01

    Sweet basil, Ocimum basilicum., is one of the most important and wildly used spices and has been shown to have antioxidant, antibacterial, and anti-diarrheal activities. In this study, high performance liquid chromatographic (HPLC) and flow-injection mass spectrometric (FIMS) fingerprinting techniques were used to differentiate organic and conventional sweet basil leaf samples. Principal component analysis (PCA) of the fingerprints indicated that both HPLC and FIMS fingerprints could effectively detect the chemical differences in the organic and conventional sweet basil leaf samples. This study suggested that the organic basil sample contained greater concentrations of almost all the major compounds than its conventional counterpart on a per same botanical weight basis. The FIMS method was able to rapidly differentiate the organic and conventional sweet basil leaf samples (1 min analysis time), whereas the HPLC fingerprints provided more information about the chemical composition of the basil samples with a longer analytical time. PMID:24518341

  20. Absorption heat pumps

    International Nuclear Information System (INIS)

    Formigoni, C.

    1998-01-01

    A brief description of the difference between a compression and an absorption heat pump is made, and the reasons why absorption systems have spread lately are given. Studies and projects recently started in the field of absorption heat pumps, as well as criteria usually followed in project development are described. An outline (performance targets, basic components) of a project on a water/air absorption heat pump, running on natural gas or LPG, is given. The project was developed by the Robur Group as an evolution of a water absorption refrigerator operating with a water/ammonia solution, which has been on the market for a long time and recently innovated. Finally, a list of the main energy and cost advantages deriving from the use of absorption heat pumps is made [it

  1. Limits of detection of americium-241 in air

    International Nuclear Information System (INIS)

    Bereznai, T.

    1995-01-01

    Seven semiconductor detectors with various characteristics (type, form, size, etc.) were tested and compared in gamma-spectrometric assays for Am-241 aerosols in air. The problem at hand (determining a low activity or attaining a set detection limit (approx. 2 mBq/m 3 ) as soon as possible after sampling) was solved best by a large-volume n-type detector with a Be-window. In addition to the detector parameters commonly used (energy resolution and effectiveness), the peak-to-background ratio and the background counting rate at the gamma-energy of the nuclide to be determined are important criteria influencing the choice of equipment. (orig.) [de

  2. Terahertz sensing of highly absorptive water-methanol mixtures with multiple resonances in metamaterials.

    Science.gov (United States)

    Chen, Min; Singh, Leena; Xu, Ningning; Singh, Ranjan; Zhang, Weili; Xie, Lijuan

    2017-06-26

    Terahertz sensing of highly absorptive aqueous solutions remains challenging due to strong absorption of water in the terahertz regime. Here, we experimentally demonstrate a cost-effective metamaterial-based sensor integrated with terahertz time-domain spectroscopy for highly absorptive water-methanol mixture sensing. This metamaterial has simple asymmetric wire structures that support multiple resonances including a fundamental Fano resonance and higher order dipolar resonance in the terahertz regime. Both the resonance modes have strong intensity in the transmission spectra which we exploit for detection of the highly absorptive water-methanol mixtures. The experimentally characterized sensitivities of the Fano and dipole resonances for the water-methanol mixtures are found to be 160 and 305 GHz/RIU, respectively. This method provides a robust route for metamaterial-assisted terahertz sensing of highly absorptive chemical and biochemical materials with multiple resonances and high accuracy.

  3. Gastrointestinal drug absorption in rats exposed to 60Co γ-radiation

    International Nuclear Information System (INIS)

    Brady, M.E.

    1976-01-01

    Following exposure of the gastrointestinal (GI) tract to ionizing radiation, its structure and function are altered for several days. Such alterations may affect the bioavailability of orally administered drugs. The potential mechanisms by which radiation may affect drug absorption were explored by studying the absorption of four test drugs, sulfanilamide, bretylium, sulfisoxazole acetyl, and riboflavin, in rats that were exposed to 850 R cobalt-60 gamma-radiation or sham irradiated. In one series of experiments, the drugs were administered orally and the amount of drug excreted in urine was used as a measure of the extent of their absorption. Cumulative urinary excretion of the drugs was shown to be a valid measure of absorption since it was not affected by radiation after intravenous administration of the drugs. At one day post-irradiation, the extent of absorption of sulfanilamide and bretylium was not affected by radiation but the absorption of sulfisoxazole acetyl and riboflavin was increased. At five days post-irradiation, there was no detectable difference between irradiated and control animals in the extent of absorption of the drugs. The fraction of sulfanilamide excreted in the urine as 4 N-conjugate was increased at one day post-irradiation. The increased excretion of metabolite appeared to result from metabolism of the drug by gut flora prior to absorption. This study shows that radiation-induced alterations in the absorption of orally administered drugs are due primarily to slowed gastric emptying. In general, slowed gastric emptying causes the rate of drug absorption to decline. The extent of absorption of drugs that are normally well absorbed is not affected by radiation while the extent of absorption of drugs that normally are absorbed poorly may be increased after irradiation of the GI tract

  4. INVISIBLE ACTIVE GALACTIC NUCLEI. II. RADIO MORPHOLOGIES AND FIVE NEW H i 21 cm ABSORPTION LINE DETECTORS

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Ting; Stocke, John T.; Darling, Jeremy [Center for Astrophysics and Space Astronomy, UCB 389, University of Colorado, Boulder, CO 80309-0389 (United States); Momjian, Emmanuel [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Sharma, Soniya [Research School of Astronomy and Astrophysics, The Australian National University, Mt Stromlo Observatory, ACT 2611 (Australia); Kanekar, Nissim [National Centre for Radio Astrophysics, TIFR, Post Bag 3, Ganeshkhind, Pune 411 007 (India)

    2016-03-15

    This is the second paper directed toward finding new highly redshifted atomic and molecular absorption lines at radio frequencies. To this end, we selected a sample of 80 candidates for obscured radio-loud active galactic nuclei (AGNs) and presented their basic optical/near-infrared (NIR) properties in Paper I. In this paper, we present both high-resolution radio continuum images for all of these sources and H i 21 cm absorption spectroscopy for a few selected sources in this sample. A-configuration 4.9 and 8.5 GHz Very Large Array continuum observations find that 52 sources are compact or have substantial compact components with size <0.″5 and flux densities >0.1 Jy at 4.9 GHz. The 36 most compact sources were then observed with the Very Long Baseline Array at 1.4 GHz. One definite and 10 candidate Compact Symmetric Objects (CSOs) are newly identified, which is a detection rate of CSOs ∼three times higher than the detection rate previously found in purely flux-limited samples. Based on possessing compact components with high flux densities, 60 of these sources are good candidates for absorption-line searches. Twenty-seven sources were observed for H i 21 cm absorption at their photometric or spectroscopic redshifts with only six detections (five definite and one tentative). However, five of these were from a small subset of six CSOs with pure galaxy optical/NIR spectra (i.e., any AGN emission is obscured) and for which accurate spectroscopic redshifts place the redshifted 21 cm line in a radio frequency intereference (RFI)-free spectral “window” (i.e., the percentage of H i 21 cm absorption-line detections could be as high as ∼90% in this sample). It is likely that the presence of ubiquitous RFI and the absence of accurate spectroscopic redshifts preclude H i detections in similar sources (only 1 detection out of the remaining 22 sources observed, 13 of which have only photometric redshifts); that is, H i absorption may well be present but is masked by

  5. Detection of Coronal Mass Ejections Using Multiple Features and Space-Time Continuity

    Science.gov (United States)

    Zhang, Ling; Yin, Jian-qin; Lin, Jia-ben; Feng, Zhi-quan; Zhou, Jin

    2017-07-01

    Coronal Mass Ejections (CMEs) release tremendous amounts of energy in the solar system, which has an impact on satellites, power facilities and wireless transmission. To effectively detect a CME in Large Angle Spectrometric Coronagraph (LASCO) C2 images, we propose a novel algorithm to locate the suspected CME regions, using the Extreme Learning Machine (ELM) method and taking into account the features of the grayscale and the texture. Furthermore, space-time continuity is used in the detection algorithm to exclude the false CME regions. The algorithm includes three steps: i) define the feature vector which contains textural and grayscale features of a running difference image; ii) design the detection algorithm based on the ELM method according to the feature vector; iii) improve the detection accuracy rate by using the decision rule of the space-time continuum. Experimental results show the efficiency and the superiority of the proposed algorithm in the detection of CMEs compared with other traditional methods. In addition, our algorithm is insensitive to most noise.

  6. Quasar Absorption Studies

    Science.gov (United States)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  7. GNU polyxmass: a software framework for mass spectrometric simulations of linear (bio-polymeric analytes

    Directory of Open Access Journals (Sweden)

    Rusconi Filippo

    2006-04-01

    Full Text Available Abstract Background Nowadays, a variety of (bio-polymers can be analyzed by mass spectrometry. The detailed interpretation of the spectra requires a huge number of "hypothesis cycles", comprising the following three actions 1 put forth a structural hypothesis, 2 test it, 3 (invalidate it. This time-consuming and painstaking data scrutiny is alleviated by using specialized software tools. However, all the software tools available to date are polymer chemistry-specific. This imposes a heavy overhead to researchers who do mass spectrometry on a variety of (bio-polymers, as each polymer type will require a different software tool to perform data simulations and analyses. We developed a software to address the lack of an integrated software framework able to deal with different polymer chemistries. Results The GNU polyxmass software framework performs common (bio-chemical simulations–along with simultaneous mass spectrometric calculations–for any kind of linear bio-polymeric analyte (DNA, RNA, saccharides or proteins. The framework is organized into three modules, all accessible from one single binary program. The modules let the user to 1 define brand new polymer chemistries, 2 perform quick mass calculations using a desktop calculator paradigm, 3 graphically edit polymer sequences and perform (bio-chemical/mass spectrometric simulations. Any aspect of the mass calculations, polymer chemistry reactions or graphical polymer sequence editing is configurable. Conclusion The scientist who uses mass spectrometry to characterize (bio-polymeric analytes of different chemistries is provided with a single software framework for his data prediction/analysis needs, whatever the polymer chemistry being involved.

  8. A review on the mass spectrometric studies of americium: Present status and future perspective.

    Science.gov (United States)

    Aggarwal, Suresh Kumar

    2018-01-01

    The manuscript reviews the various mass spectrometric techniques for analysis and chemical studies of Americium. These methods include thermal ionization mass spectrometry (TIMS), and inductively coupled plasma source mass spectrometry (ICPMS) for the determination of Am isotope ratios and concentration in nuclear fuel samples of interest in nuclear technology, and in complex biological and environmental samples. Ultra-sensitive mass spectrometric techniques of resonance-ionization mass spectrometry (RIMS), and accelerator-based mass spectrometry (AMS) are also discussed. The novel applications of electrospray ionization mass spectrometry (ESIMS) to understand the solution chemistry of Am and other actinides are presented. These studies are important in view of the world-wide efforts to develop novel complexing agents to separate lanthanides and minor actinides (Am, Np, and Cm) for partitioning and transmutation of minor actinides from the point of view of nuclear waste management. These mass spectrometry experiments are also of great interest to examine the covalent character of actinides with increasing atomic number. Studies on gas-phase chemistry of Am and its oxides with Knudsen effusion mass spectrometry (KEMS), Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS), and laser-based experiments with reflectron time-of-flight mass spectrometer (R-ToF) are highlighted. These studies are important to understand the fundamental chemistry of 5f electrons in actinides. Requirement of certified isotopic reference materials of Am to improve the accuracy of experimental nuclear data (e.g., the half-life of 243 Am) is emphasized. © 2016 Wiley Periodicals, Inc. Mass Spec Rev. © 2016 Wiley Periodicals, Inc.

  9. Mono-, di- and trimethylated homologues of isoprenoid tetraether lipid cores in archaea and environmental samples: mass spectrometric identification and significance.

    Science.gov (United States)

    Knappy, Chris; Barillà, Daniela; Chong, James; Hodgson, Dominic; Morgan, Hugh; Suleman, Muhammad; Tan, Christine; Yao, Peng; Keely, Brendan

    2015-12-01

    Higher homologues of widely reported C(86) isoprenoid diglycerol tetraether lipid cores, containing 0-6 cyclopentyl rings, have been identified in (hyper)thermophilic archaea, representing up to 21% of total tetraether lipids in the cells. Liquid chromatography-tandem mass spectrometry confirms that the additional carbon atoms in the C(87-88) homologues are located in the etherified chains. Structures identified include dialkyl and monoalkyl ('H-shaped') tetraethers containing C(40-42) or C(81-82) hydrocarbons, respectively, many representing novel compounds. Gas chromatography-mass spectrometric analysis of hydrocarbons released from the lipid cores by ether cleavage suggests that the C(40) chains are biphytanes and the C(41) chains 13-methylbiphytanes. Multiple isomers, having different chain combinations, were recognised among the dialkyl lipids. Methylated tetraethers are produced by Methanothermobacter thermautotrophicus in varying proportions depending on growth conditions, suggesting that methylation may be an adaptive mechanism to regulate cellular function. The detection of methylated lipids in Pyrobaculum sp. AQ1.S2 and Sulfolobus acidocaldarius represents the first reported occurrences in Crenarchaeota. Soils and aquatic sediments from geographically distinct mesotemperate environments that were screened for homologues contained monomethylated tetraethers, with di- and trimethylated structures being detected occasionally. The structural diversity and range of occurrences of the C(87-89) tetraethers highlight their potential as complementary biomarkers for archaea in natural environments. Copyright © 2015 John Wiley & Sons, Ltd.

  10. XMM-Newton Survey of Local O VII Absorption Lines in the Spectra of Galactic X-Ray Sources

    Science.gov (United States)

    Luo, Yang; Fang, Taotao; Ma, Renyi

    2018-04-01

    The detection of highly ionized metal absorption lines in the X-ray spectra of the Galactic X-ray binaries (XRBs) implies the distribution of hot gas along the sightline toward the background sources. However, the origin of this hot gas is still unclear: it can arise in the hot interstellar medium (ISM), or is intrinsic to the XRBs. In this paper, we present an XMM-Newton survey of the O VII absorption lines in the spectra of Galactic XRBs. A total of 33 XRBs were selected, with 29 low-mass XRBs and 4 high-mass XRBs. At a more than 3σ threshold, O VII absorption line was detected in 16 targets, among which 4 were newly discovered in this work. The average line equivalent width is centered around ∼20 mÅ. Additionally, we do not find strong correlations between the O VII EWs and the Galactic neutral absorption N H, the Galactic coordinates, or the distance of background targets. Such non-correlation may suggest contamination of the circumstellar material, or a lack of constraints on the line Doppler-b parameter. We also find that regardless of the direction of the XRBs, the O VII absorption lines are always detected when the flux of the background XRBs reaches a certain level, suggesting a uniform distribution of this hot gas. We estimate a ratio of 0.004–0.4 between the hot and neutral phases of the ISM. This is the second paper in the series following Fang et al. (2015), in which we focused on the local O VII absorption lines detected in the background AGN spectra. Detailed modeling of the hot ISM distribution will be investigated in a future paper.

  11. Forty-five degree backscattering-mode nonlinear absorption imaging in turbid media.

    Science.gov (United States)

    Cui, Liping; Knox, Wayne H

    2010-01-01

    Two-color nonlinear absorption imaging has been previously demonstrated with endogenous contrast of hemoglobin and melanin in turbid media using transmission-mode detection and a dual-laser technology approach. For clinical applications, it would be generally preferable to use backscattering mode detection and a simpler single-laser technology. We demonstrate that imaging in backscattering mode in turbid media using nonlinear absorption can be obtained with as little as 1-mW average power per beam with a single laser source. Images have been achieved with a detector receiving backscattered light at a 45-deg angle relative to the incoming beams' direction. We obtain images of capillary tube phantoms with resolution as high as 20 microm and penetration depth up to 0.9 mm for a 300-microm tube at SNR approximately 1 in calibrated scattering solutions. Simulation results of the backscattering and detection process using nonimaging optics are demonstrated. A Monte Carlo-based method shows that the nonlinear signal drops exponentially as the depth increases, which agrees well with our experimental results. Simulation also shows that with our current detection method, only 2% of the signal is typically collected with a 5-mm-radius detector.

  12. Near-perfect broadband absorption from hyperbolic metamaterial nanoparticles

    Science.gov (United States)

    Riley, Conor T.; Smalley, Joseph S. T.; Brodie, Jeffrey R. J.; Fainman, Yeshaiahu; Sirbuly, Donald J.; Liu, Zhaowei

    2017-02-01

    Broadband absorbers are essential components of many light detection, energy harvesting, and camouflage schemes. Current designs are either bulky or use planar films that cause problems in cracking and delamination during flexing or heating. In addition, transferring planar materials to flexible, thin, or low-cost substrates poses a significant challenge. On the other hand, particle-based materials are highly flexible and can be transferred and assembled onto a more desirable substrate but have not shown high performance as an absorber in a standalone system. Here, we introduce a class of particle absorbers called transferable hyperbolic metamaterial particles (THMMP) that display selective, omnidirectional, tunable, broadband absorption when closely packed. This is demonstrated with vertically aligned hyperbolic nanotube (HNT) arrays composed of alternating layers of aluminum-doped zinc oxide and zinc oxide. The broadband absorption measures >87% from 1,200 nm to over 2,200 nm with a maximum absorption of 98.1% at 1,550 nm and remains large for high angles. Furthermore, we show the advantages of particle-based absorbers by transferring the HNTs to a polymer substrate that shows excellent mechanical flexibility and visible transparency while maintaining near-perfect absorption in the telecommunications region. In addition, other material systems and geometries are proposed for a wider range of applications.

  13. Effects of Omeprazole on Iron Absorption: Preliminary Study

    Directory of Open Access Journals (Sweden)

    Mahmut Yaşar Çeliker

    2013-09-01

    Full Text Available Objective: Increasing numbers of pediatric and adult patients are being treated with proton pump inhibitors (PPIs. PPIs are known to inhibit gastric acid secretion. Nonheme iron requires gastric acid for conversion to the ferrous form for absorption. Ninety percent of dietary and 100% of oral iron therapy is in the nonheme form. To the best of our knowledge, the effect of PPIs on iron absorption has not been studied in humans. Our study assessed the relationship between omeprazole therapy and iron absorption in healthy subjects. Materials and Methods: We recruited 9 healthy volunteers between June 2010 and March 2011. Subjects with chronic illness, anemia, or use of PPI therapy were excluded. Serum iron concentrations were measured 1, 2, and 3 h after the ingestion of iron (control group. The measurements were repeated on a subsequent visit after 4 daily oral administrations of omeprazole at a dose of 40 mg (treatment group. Results: One female and 8 male volunteers were enrolled in the study with a mean age of 33 years. There was no statistical difference detected between baseline, 1-h, 2-h, and 3-h iron levels between control and treatment groups. Conclusion: Administration of omeprazole for a short duration does not affect absorption of orally administered iron in healthy individuals.

  14. Determination of iodine to compliment mass spectrometric measurements

    International Nuclear Information System (INIS)

    Hohorst, F.A.

    1994-11-01

    The dose of iodine-129 to facility personnel and the general public as a result of past, present, and future activities at DOE sites is of continuing interest, WINCO received about 160 samples annually in a variety of natural matrices, including snow, milk, thyroid tissue, and sagebrush, in which iodine-129 is determined in order to evaluate this dose, Currently, total iodine and the isotopic ratio of iodine-127 to iodine-129 are determined by mass spectrometry. These two measurements determine the concentration of iodine-129 in each sample, These measurements require at least 16 h of mass spectrometer operator time for each sample. A variety of methods are available which concentrate and determine small quantities of iodine. Although useful, these approaches would increase both time and cost. The objective of this effort was to determine total iodine by an alternative method in order to decrease the load on mass spectrometry by 25 to 50%. The preparation of each sample for mass spectrometric analysis involves a common step--collection of iodide on an ion exchange bed. This was the focal point of the effort since the results would be applicable to all samples

  15. Time-resolved photoion imaging spectroscopy: Determining energy distribution in multiphoton absorption experiments

    Science.gov (United States)

    Qian, D. B.; Shi, F. D.; Chen, L.; Martin, S.; Bernard, J.; Yang, J.; Zhang, S. F.; Chen, Z. Q.; Zhu, X. L.; Ma, X.

    2018-04-01

    We propose an approach to determine the excitation energy distribution due to multiphoton absorption in the case of excited systems following decays to produce different ion species. This approach is based on the measurement of the time-resolved photoion position spectrum by using velocity map imaging spectrometry and an unfocused laser beam with a low fluence and homogeneous profile. Such a measurement allows us to identify the species and the origin of each ion detected and to depict the energy distribution using a pure Poisson's equation involving only one variable which is proportional to the absolute photon absorption cross section. A cascade decay model is used to build direct connections between the energy distribution and the probability to detect each ionic species. Comparison between experiments and simulations permits the energy distribution and accordingly the absolute photon absorption cross section to be determined. This approach is illustrated using C60 as an example. It may therefore be extended to a wide variety of molecules and clusters having decay mechanisms similar to those of fullerene molecules.

  16. Development of absorption fiber optic sensor for distributed measurement of ammonia gas

    Science.gov (United States)

    Aubrecht, J.; Kalvoda, L.

    2013-05-01

    Polymer-clad silica optical fibers are employed for development of different absorption optic fiber sensors of gaseous analytes. In our case, the physical principles of the detection are combined with a chemical reaction between analyte and suitable opto-chemical absorption reagents. Selected organometallic complex reagents with different lengths of lateral aliphatic chains are studied with respect to the type of central ions and their coordinative conditions to surrounding ligands. The effect of solvent type on solubility and the long-term stability of the prepared reagents in solid matrix are presented and discussed. Various methods are also tested in order to achieve an effective reagent immobilization into the polymer matrix, which creates optical fiber cladding. The chemical reaction of the reagents with ammonia based on ligand exchange process is accompanied by changes of visible-near-infrared optical absorption influencing via evanescent field on the guided light intensity. Experimental results suggest that the selected reagents provide optical properties suitable for practical sensing applications and that the sensitized PCS optical fibers could be used for detection of ammonia gas.

  17. Extraction and preconcentration of trace levels of cobalt using functionalized magnetic nanoparticles in a sequential injection lab-on-valve system with detection by electrothermal atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Wang Yang; Luo Xiaoyu; Tang Jie; Hu Xiaoya; Xu Qin; Yang Chun

    2012-01-01

    Graphical abstract: An approach to performing extraction and preconcentration employing functionalized magnetic particles for the determination of cobalt in the sequential injection lab-on-valve system using detection by electrothermal atomic absorption spectrometry. Highlights: ► New SPE method for cobalt separation/preconcentration was reported. ► Functionalized magnetic nanoparticles were used as adsorbent. ► Extraction, elution, and detection procedures were performed in the LOV system. ► This automatic extraction technique provided a good platform for metal analysis. - Abstract: A new approach to performing extraction and preconcentration employing functionalized magnetic nanoparticles for the determination of trace metals is presented. Alumina-coated iron oxide nanoparticles were synthesized and used as the solid support. The nanoparticles were functionalized with sodium dodecyl sulfate and used as adsorbents for solid phase extraction of the analyte. Extraction, elution, and detection procedures were performed sequentially in the sequential injection lab-on-valve (SI-LOV) system followed by electrothermal atomic absorption spectrometry (ETAAS). Mixtures of hydrophobic analytes were successfully extracted from solution using the synthesized magnetic adsorbents. The potential use of the established scheme was demonstrated by taking cobalt as a model analyte. Under the optimal conditions, the calibration curve showed an excellent linearity in the concentration range of 0.01–5 μg L −1 , and the relative standard deviation was 2.8% at the 0.5 μg L −1 level (n = 11). The limit of detection was 6 ng L −1 with a sampling frequency of 18 h −1 . The present method has been successfully applied to cobalt determination in water samples and two certified reference materials.

  18. Direct Detection of Pharmaceuticals and Personal Care Products from Aqueous Samples with Thermally-Assisted Desorption Electrospray Ionization Mass Spectrometry

    Science.gov (United States)

    Campbell, Ian S.; Ton, Alain T.; Mulligan, Christopher C.

    2011-07-01

    An ambient mass spectrometric method based on desorption electrospray ionization (DESI) has been developed to allow rapid, direct analysis of contaminated water samples, and the technique was evaluated through analysis of a wide array of pharmaceutical and personal care product (PPCP) contaminants. Incorporating direct infusion of aqueous sample and thermal assistance into the source design has allowed low ppt detection limits for the target analytes in drinking water matrices. With this methodology, mass spectral information can be collected in less than 1 min, consuming ~100 μL of total sample. Quantitative ability was also demonstrated without the use of an internal standard, yielding decent linearity and reproducibility. Initial results suggest that this source configuration is resistant to carryover effects and robust towards multi-component samples. The rapid, continuous analysis afforded by this method offers advantages in terms of sample analysis time and throughput over traditional hyphenated mass spectrometric techniques.

  19. A novel solidified floating organic drop microextraction method for preconcentration and determination of copper ions by flow injection flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Sahin, Cigdem Arpa; Tokgoez, Ilknur

    2010-01-01

    A rapid, simple and cost effective solidified floating organic drop microextraction (SFODME) and flow injection flame atomic absorption spectrometric determination (FI-FAAS) method for copper was developed. In this method, a free microdrop of 1-undecanol containing 1,5-diphenyl carbazide (DPC) as the complexing agent was transferred to the surface of an aqueous sample including Cu(II) ions, while being agitated by a stirring bar in the bulk of the solution. Under the proper stirring conditions, the suspended microdrop can remain at the top-center position of the aqueous sample. After the completion of the extraction, the sample vial was cooled by placing it in a refrigerator for 10 min. The solidified microdrop was then transferred into a conical vial, where it melted immediately and diluted to 300 μL with ethanol. Finally, copper ions in 200 μL of diluted solution were determined by FI-FAAS. Several factors affecting the microextraction efficiency, such as type of extraction solvent, pH, complexing agent concentration, extraction time, stirring rate, sample volume and temperature were investigated and optimized. Under optimized conditions for 100 mL of solution, the preconcentration factor was 333 and the enrichment factor was 324. The limit of detection (3 s) was 0.4 ng mL -1 , the limit of quantification (10 s) was 1.1 ng mL -1 and the relative standard deviation (RSD) for 10 replicate measurements of 10 ng mL -1 copper was 0.9%. The proposed method was successfully applied to the determination of copper in different water samples.

  20. NuSTAR Reveals Extreme Absorption in z < 0.5 Type 2 Quasars

    Science.gov (United States)

    Lansbury, G. B.; Gandhi, P.; Alexander, D. M.; Assef, R. J.; Aird, J.; Annuar, A.; Ballantyne, D. R.; Baloković, M.; Bauer, F. E.; Boggs, S. E.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Civano, F.; Comastri, A.; Craig, W. W.; Del Moro, A.; Grefenstette, B. W.; Hailey, C. J.; Harrison, F. A.; Hickox, R. C.; Koss, M.; LaMassa, S. M.; Luo, B.; Puccetti, S.; Stern, D.; Treister, E.; Vignali, C.; Zappacosta, L.; Zhang, W. W.

    2015-08-01

    The intrinsic column density (NH) distribution of quasars is poorly known. At the high obscuration end of the quasar population and for redshifts z 1.5 × 1024 cm-2) type 2 quasars (CTQSO2s); five new NuSTAR observations are reported herein, and four have been previously published. The candidate CTQSO2s lie at z < 0.5, have observed [O iii] luminosities in the range 8.4\\lt {log}({L}[{{O} {{III}}]}/{L}⊙ )\\lt 9.6, and show evidence for extreme, Compton-thick absorption when indirect absorption diagnostics are considered. Among the nine candidate CTQSO2s, five are detected by NuSTAR in the high-energy (8-24 keV) band: two are weakly detected at the ≈3σ confidence level and three are strongly detected with sufficient counts for spectral modeling (≳90 net source counts at 8-24 keV). For these NuSTAR-detected sources direct (i.e., X-ray spectral) constraints on the intrinsic active galactic nucleus properties are feasible, and we measure column densities ≈2.5-1600 times higher and intrinsic (unabsorbed) X-ray luminosities ≈10-70 times higher than pre-NuSTAR constraints from Chandra and XMM-Newton. Assuming the NuSTAR-detected type 2 quasars are representative of other Compton-thick candidates, we make a correction to the NH distribution for optically selected type 2 quasars as measured by Chandra and XMM-Newton for 39 objects. With this approach, we predict a Compton-thick fraction of {f}{CT}={36}-12+14 %, although higher fractions (up to 76%) are possible if indirect absorption diagnostics are assumed to be reliable.

  1. Precision atomic beam density characterization by diode laser absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Oxley, Paul; Wihbey, Joseph [Physics Department, The College of the Holy Cross, Worcester, Massachusetts 01610 (United States)

    2016-09-15

    We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10{sup −5} are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10{sup 4} atoms cm{sup −3}. The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

  2. Precision atomic beam density characterization by diode laser absorption spectroscopy

    International Nuclear Information System (INIS)

    Oxley, Paul; Wihbey, Joseph

    2016-01-01

    We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10 −5 are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10 4 atoms cm −3 . The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

  3. Precision atomic beam density characterization by diode laser absorption spectroscopy.

    Science.gov (United States)

    Oxley, Paul; Wihbey, Joseph

    2016-09-01

    We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10 -5 are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10 4 atoms cm -3 . The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

  4. Onward treatment of irradiated liquid egg: Detection in sponge cake mixture after baking by means of LC-GC-MS. Weiterverarbeitung von bestrahltem Fluessigei: Nachweis in gebackener Biskuitmasse mittels LC-GC-MS

    Energy Technology Data Exchange (ETDEWEB)

    Grabowski, H.U. von (Staatliches Lebensmitteluntersuchungsamt Oldenburg (Germany)); Schulzki, G. (Fachgebietsgruppe Lebensmittel- und Arzneimittelbestrahlung, Bundesgesundheitsamt, Berlin (Germany)); Pfordt, J. (Staatliches Lebensmitteluntersuchungsamt Oldenburg (Germany)); Spiegelberg, A. (Fachgebietsgruppe Lebensmittel- und Arzneimittelbestrahlung, Bundesgesundheitsamt, Berlin (Germany)); Helle, N. (Fachgebietsgruppe Lebensmittel- und Arzneimittelbestrahlung, Bundesgesundheitsamt, Berlin (Germany)); Boegl, K.W. (Fachgebietsgruppe Lebensmittel- und Arzneimittelbestrahlung, Bundesgesundheitsamt, Berlin (Germany)); Schreiber, G.A. (Fachgebietsgruppe Lebensmittel- und Arzneimittelbestrahlung, Bundesgesundheitsamt, Berlin (Germany))

    1993-09-01

    Irradiated whole liquid egg used for preparation of sponge cake could be identified using gaschromatographic/mass spectrometric detection of the radiation induced hydrocarbons for doses from 1 kGy. Separation of the hydrocarbons out of the fat was carried out by HPLC coupled on-line to the GC. That means, for the first time an irradiated component of a heat treated food could be detected. (orig.)

  5. Combined Determination of Poly-β-Hydroxyalkanoic and Cellular Fatty Acids in Starved Marine Bacteria and Sewage Sludge by Gas Chromatography with Flame Ionization or Mass Spectrometry Detection

    Science.gov (United States)

    Odham, Göran; Tunlid, Anders; Westerdahl, Gunilla; Mårdén, Per

    1986-01-01

    Extraction of lipids from bacterial cells or sewage sludge samples followed by simple and rapid extraction procedures and room temperature esterification with pentafluorobenzylbromide allowed combined determinations of poly-β-hydroxyalkanoate constituents and fatty acids. Capillary gas chromatography and flame ionization or mass spectrometric detection was used. Flame ionization permitted determination with a coefficient of variation ranging from 10 to 27% at the picomolar level, whereas quantitative chemical ionization mass spectrometry afforded sensitivities for poly-β-hydroxyalkanoate constituuents in the attomolar range. The latter technique suggests the possibility of measuring such components in bacterial assemblies with as few as 102 cells. With the described technique using flame ionization detection, it was possible to study the rapid formation of poly-β-hydroxyalkanoate during feeding of a starved marine bacterium isolate with a complex medium or glucose and correlate the findings to changes in cell volumes. Mass spectrometric detection of short β-hydroxy acids in activated sewage sludge revealed the presence of 3-hydroxybutyric, 3-hydroxyhexanoic, and 3-hydroxyoctanoic acids in the relative proportions of 56, 5 and 39%, respectively. No odd-chain β-hydroxy acids were found. PMID:16347181

  6. Carbon filter property detection with thermal neutron technique

    International Nuclear Information System (INIS)

    Deng Zhongbo; Han Jun; Li Wenjie

    2003-01-01

    The paper discussed the mechanism that the antigas property of the carbon filter will decrease because of its carbon bed absorbing water from the air while the carbon filter is being stored, and introduced the principle and method of detection the amount of water absorption with thermal neutron technique. Because some certain relation between the antigas property of the carbon filter and the amount of water absorption exists, the decrease degree of the carbon filter antigas property can be estimated through the amount of water absorption, offering a practicable facility technical pathway to quickly non-destructively detect the carbon filter antigas property

  7. Comparison of water absorption methods: testing the water absorption of recently quarried and weathered porous limestone on site and under laboratory conditions

    Science.gov (United States)

    Rozgonyi-Boissinot, Nikoletta; Agárdi, Tamás; Karolina Cebula, Ágnes; Török, Ákos

    2017-04-01

    absorbed amount of water was detected. The obtained 29-30m% water absorption values compared to the 30-35m% of the total porosity of the stone, clearly suggest that the pores can be saturated with water under standard barometric pressure and therefore the tested porous Miocene limestones are very prone to salt attack.

  8. Matrix-assisted laser-desorption/ionization mass spectrometric imaging of olanzapine in a single hair using esculetin as a matrix.

    Science.gov (United States)

    Wang, Hang; Wang, Ying; Wang, Ge; Hong, Lizhi

    2017-07-15

    Matrix-assisted laser desorption/ionization-mass spectrometric imaging (MALDI-MSI) for the analysis of intact hair is a powerful tool for monitoring changes in drug consumption. The embedding of a low drug concentration in the hydrophobic hair matrix makes it difficult to extract and detect, and requires an improved method to increase detection sensitivity. In this study, an MSI method using MALDI-Fourier transform ion cyclotron resonance was developed for direct identification and imaging of olanzapine in hair samples using the positive ion mode. Following decontamination, scalp hair samples from an olanzapine user were scraped from the proximal to the distal end three times, and 5mm hair sections were fixed onto an Indium-Tin-Oxide (ITO)-coated microscopic glass slide. Esculetin (6,7-dihydroxy-2H-chromen-2-one) was used as a new hydrophobic matrix to increase the affinity, extraction and ionization efficiency of olanzapine in the hair samples. The spatial distribution of olanzapine was observed using five single hairs from the same drug user. This matrix improves the affinity of olanzapine in hair for molecular imaging with mass spectrometry. This method may provide a detection power for olanzapine to the nanogram level per 5mm hair. Time course changes in the MSI results were also compared with quantitative HPLC-MS/MS for each 5mm segment of single hair shafts selected from the MALDI target. MALDI imaging intensities in single hairs showed good semi-quantitative correlation with the results from conventional HPLC-MS/MS. MALDI-MSI is suitable for monitoring drug intake with a high time resolution. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

    Directory of Open Access Journals (Sweden)

    Stefanie Wolfram

    2014-10-01

    Full Text Available Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy-5-(4-bromophenyl-2-(pyridin-2-ylthiazole for fluorescence, UV and mass spectrometry (MS detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously compares with commercially available azide-modified fluorophores and a brominated one. The ease of synthesis, small size, stability, and the universal detection possibilities make it an ideal reporter for activity-based protein profiling and functional metabolic profiling.

  10. A Sensitive and Robust Ultra HPLC Assay with Tandem Mass Spectrometric Detection for the Quantitation of the PARP Inhibitor Olaparib (AZD2281 in Human Plasma for Pharmacokinetic Application

    Directory of Open Access Journals (Sweden)

    Jeffrey Roth

    2014-06-01

    Full Text Available Olaparib (AZD2281 is an orally active PARP-1 inhibitor, primarily effective against cancers with BRCA1/2 mutations. It is currently in Phase III development and has previously been investigated in numerous clinical trials, both as a single agent and in combination with chemotherapy. Despite this widespread testing, there is only one published method that provides assay details and stability studies for olaparib alone. A more sensitive uHPLC-MS/MS method for the quantification of olaparib in human plasma was developed, increasing the range of quantification at both ends (0.5–50,000 ng/mL compared to previously published methods (10–5,000 ng/mL. The wider range encompasses CMAX levels produced by typical olaparib doses and permits better pharmacokinetic modeling of olaparib elimination. This assay also utilizes a shorter analytical runtime, allowing for more rapid quantification and reduced use of reagents. A liquid-liquid extraction was followed by chromatographic separation on a Waters UPLC® BEH C18 column (2.1 × 50 mm, 1.7 µm and mass spectrometric detection. The mass transitions m/z 435.4→281.1 and m/z 443.2→281.1 were used for olaparib and the internal standard [2H8]-olaparib, respectively. The assay proved to be accurate (<9% deviation and precise (CV < 11%. Stability studies showed that olaparib is stable at room temperature for 24 h. in whole blood, at 4 °C for 24 h post-extraction, at −80 °C in plasma for at least 19 months, and through three freeze-thaw cycles. This method proved to be robust for measuring olaparib levels in clinical samples from a Phase I trial.

  11. Polarization control of intermediate state absorption in resonance-mediated multi-photon absorption process

    International Nuclear Information System (INIS)

    Xu, Shuwu; Yao, Yunhua; Jia, Tianqing; Ding, Jingxin; Zhang, Shian; Sun, Zhenrong; Huang, Yunxia

    2015-01-01

    We theoretically and experimentally demonstrate the control of the intermediate state absorption in an (n + m) resonance-mediated multi-photon absorption process by the polarization-modulated femtosecond laser pulse. An analytical solution of the intermediate state absorption in a resonance-mediated multi-photon absorption process is obtained based on the time-dependent perturbation theory. Our theoretical results show that the control efficiency of the intermediate state absorption by the polarization modulation is independent of the laser intensity when the transition from the intermediate state to the final state is coupled by the single-photon absorption, but will be affected by the laser intensity when this transition is coupled by the non-resonant multi-photon absorption. These theoretical results are experimentally confirmed via a two-photon fluorescence control in (2 + 1) resonance-mediated three-photon absorption of Coumarin 480 dye and a single-photon fluorescence control in (1 + 2) resonance-mediated three-photon absorption of IR 125 dye. (paper)

  12. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Recker, R.R.

    1985-01-01

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  13. Absorption and metabolic fate of bioactive dietary benzoxazinoids in humans

    DEFF Research Database (Denmark)

    Adhikari, Khem B; Laursen, Bente B; Gregersen, Per L

    2013-01-01

    benzoxazinoids with abundant HBOA-Glc (219 nmol × μmol−1 of creatinine). The sulfate and glucuronide conjugates of 2-hydroxy-1,4-benzoxazin-3-one (HBOA) and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) were detected in plasma and urine, indicating substantial phase II metabolism. Direct absorption of lactam......Scope Benzoxazinoids, which are natural compounds recently identified in mature whole grain cereals and bakery products, have been suggested to have a range of pharmacological properties and health-protecting effects. There are no published reports concerned with the absorption and metabolism...... of bioactive benzoxazinoids in humans. Methods and results The absorption, metabolism, and excretion of ten different dietary benzoxazinoids were examined by LC-MS/MS by analyzing plasma and urine from 20 healthy human volunteers after daily intake of 143 μmol of total benzoxazinoids from rye bread and rye...

  14. High sensitivity probe absorption technique for time-of-flight ...

    Indian Academy of Sciences (India)

    Abstract. We report on a phase-sensitive probe absorption technique with high sen- sitivity, capable of detecting a few hundred ultra-cold atoms in flight in an observation time of a few milliseconds. The large signal-to-noise ratio achieved is sufficient for reliable measurements on low intensity beams of cold atoms.

  15. A blind green bank telescope millimeter-wave survey for redshifted molecular absorption

    Energy Technology Data Exchange (ETDEWEB)

    Kanekar, N.; Gupta, A. [National Centre for Radio Astrophysics, TIFR, Ganeshkhind, Pune 411007 (India); Carilli, C. L. [National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801 (United States); Stocke, J. T. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Willett, K. W., E-mail: nkanekar@ncra.tifr.res.in [School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

    2014-02-10

    We present the methodology for 'blind' millimeter-wave surveys for redshifted molecular absorption in the CO/HCO{sup +} rotational lines. The frequency range 30-50 GHz appears optimal for such surveys, providing sensitivity to absorbers at z ≳ 0.85. It is critical that the survey is 'blind', i.e., based on a radio-selected sample, including sources without known redshifts. We also report results from the first large survey of this kind, using the Q-band receiver on the Green Bank Telescope (GBT) to search for molecular absorption toward 36 sources, 3 without known redshifts, over the frequency range 39.6-49.5 GHz. The GBT survey has a total redshift path of Δz ≈ 24, mostly at 0.81 < z < 1.91, and a sensitivity sufficient to detect equivalent H{sub 2} column densities ≳ 3 × 10{sup 21} cm{sup –2} in absorption at 5σ significance (using CO-to-H{sub 2} and HCO{sup +}-to-H{sub 2} conversion factors of the Milky Way). The survey yielded no confirmed detections of molecular absorption, yielding the 2σ upper limit n(z = 1.2) < 0.15 on the redshift number density of molecular gas at column densities N(H{sub 2}) ≳ 3 × 10{sup 21} cm{sup –2}.

  16. Analysis of Dithiocarbamate Fungicides in Vegetable Matrices Using HPLC-UV Followed by Atomic Absorption Spectrometry.

    Science.gov (United States)

    Al-Alam, Josephine; Bom, Laura; Chbani, Asma; Fajloun, Ziad; Millet, Maurice

    2017-04-01

    A simple method combining ion-pair methylation, high-performance liquid chromatography (HPLC) analysis with detection at 272 nm and atomic absorption spectrometry was developed in order to determine 10 dithiocarbamate fungicides (Dazomet, Metam-sodium, Ferbam, Ziram, Zineb, Maneb, Mancozeb, Metiram, Nabam and Propineb) and distinguish ethylenbisdithiocarbamates (EBDTCs) Zineb, Maneb and Mancozeb in diverse matrices. This method associates reverse phase analysis by HPLC analysis with detection at 272 nm, with atomic absorption spectrometry in order to distinguish, with the same extraction protocol, Maneb, Mancozeb and Zineb. The limits of detection (0.4, 0.8, 0.5, 1.25 and 1.97) and quantification (1.18, 2.5, 1.52, 4.2 and 6.52) calculated in injected nanogram, respectively, for Dazomet, Metam-Na, dimethyldithiocarbamates (DMDTCs), EBDTCs and propylenebisdithiocarbamates (PBDTCs) justify the sensitivity of the method used. The coefficients of determination R2 were 0.9985, 0.9978, 0.9949, 0.988 and 0.9794, respectively, for Dazomet, Metam-Na, DMDTCs, EBDTCs and PBDTCs, and the recovery from fortified apple and leek samples was above 90%. Results obtained with the atomic absorption method in comparison with spectrophotometric analysis focus on the importance of the atomic absorption as a complementary specific method for the distinction between different EBDTCs fungicides. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. A Mass Spectrometric Analysis Method Based on PPCA and SVM for Early Detection of Ovarian Cancer.

    Science.gov (United States)

    Wu, Jiang; Ji, Yanju; Zhao, Ling; Ji, Mengying; Ye, Zhuang; Li, Suyi

    2016-01-01

    Background. Surfaced-enhanced laser desorption-ionization-time of flight mass spectrometry (SELDI-TOF-MS) technology plays an important role in the early diagnosis of ovarian cancer. However, the raw MS data is highly dimensional and redundant. Therefore, it is necessary to study rapid and accurate detection methods from the massive MS data. Methods. The clinical data set used in the experiments for early cancer detection consisted of 216 SELDI-TOF-MS samples. An MS analysis method based on probabilistic principal components analysis (PPCA) and support vector machine (SVM) was proposed and applied to the ovarian cancer early classification in the data set. Additionally, by the same data set, we also established a traditional PCA-SVM model. Finally we compared the two models in detection accuracy, specificity, and sensitivity. Results. Using independent training and testing experiments 10 times to evaluate the ovarian cancer detection models, the average prediction accuracy, sensitivity, and specificity of the PCA-SVM model were 83.34%, 82.70%, and 83.88%, respectively. In contrast, those of the PPCA-SVM model were 90.80%, 92.98%, and 88.97%, respectively. Conclusions. The PPCA-SVM model had better detection performance. And the model combined with the SELDI-TOF-MS technology had a prospect in early clinical detection and diagnosis of ovarian cancer.

  18. Natural gas pipeline leak detector based on NIR diode laser absorption spectroscopy.

    Science.gov (United States)

    Gao, Xiaoming; Fan, Hong; Huang, Teng; Wang, Xia; Bao, Jian; Li, Xiaoyun; Huang, Wei; Zhang, Weijun

    2006-09-01

    The paper reports on the development of an integrated natural gas pipeline leak detector based on diode laser absorption spectroscopy. The detector transmits a 1.653 microm DFB diode laser with 10 mW and detects a fraction of the backscatter reflected from the topographic targets. To eliminate the effect of topographic scatter targets, a ratio detection technique was used. Wavelength modulation and harmonic detection were used to improve the detection sensitivity. The experimental detection limit is 50 ppmm, remote detection for a distance up to 20 m away topographic scatter target is demonstrated. Using a known simulative leak pipe, minimum detectable pipe leak flux is less than 10 ml/min.

  19. Broadband and wide angle near-unity absorption in graphene-insulator-metal thin film stacks

    Science.gov (United States)

    Zhang, H. J.; Zheng, G. G.; Chen, Y. Y.; Xu, L. H.

    2018-05-01

    Broadband unity absorption in graphene-insulator-metal (GIM) structures is demonstrated in the visible (VIS) and near-infrared (NIR) spectra. The spectral characteristics possess broadband absorption peaks, by simply choosing a stack of GIM, while no nanofabrication steps and patterning are required, and thus can be easily fabricated to cover a large area. The electromagnetic (EM) waves can be entirely trapped and the absorption can be greatly enhanced are verified with the finite-difference time-domain (FDTD) and rigorous coupled wave analysis (RCWA) methods. The position and the number of the absorption peak can be totally controlled by adjusting the thickness of the insulator layer. The proposed absorber maintains high absorption (above 90%) for both transverse electric (TE) and transverse magnetic (TM) polarizations, and for angles of incidence up to 80°. This work opens up a promising approach to realize perfect absorption (PA) with ultra-thin film, which could implicate many potential applications in optical detection and optoelectronic devices.

  20. Method Validation for the Gamma-ray Spectrometric Determination of Natural Radioactive Nuclides in NORM Samples - Method Validation for the Gamma-ray Spectrometric Determination of Natural Radionuclides in raw materials and by-products

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Young-Yong; Lim, Jong-Myoung; Jang, Mee; Kim, Chang-Jong; Chung, Kun Ho; Kang, Mun Ja; Choi, Geun-Sik [Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989, Yuseong, Daejeon, 305-353 (Korea, Republic of)

    2014-07-01

    It has established the 'Act on safety control of radioactive rays around living environment' in Korea, since 2011, to protect the public from natural occurring radioactive materials (NORM) and their by-products. The increasing concerns regarding the radioactivity of those materials therefore dictate many demands for the radioactive analysis for them. There are several methods to determine the concentration of natural radionuclides, such as {sup 235}U, {sup 238}U, {sup 226}Ra, {sup 232}Th, and so on, through a radiochemical analysis using an alpha spectrometer, mass spectrometer and liquid scintillation counter. However, gamma-ray spectroscopy still has an effect on the assessment of radioactive concentration for these nuclides and their progenies. To adapt a gamma spectrometer to the determination of natural radionuclides, the feasibility of their analysis methods should be first verified and validated with respect to accuracy and time and cost constraints. In general, one of the well-known processes in analyzing uranium with a gamma spectrometer is an indirect measurement using the secular equilibrium state with their progenies in a sample. This method, however, demands the time elapsed about 3 weeks to reach the equilibrium state between {sup 226}Ra and {sup 222}Rn and the sufficient integrity of a sample bottle to prevent the leakage of radon isotopes which is a form of noble gas. The simple and quick method is to directly measure a full energy absorption peak of 186.2 keV from {sup 226}Ra without the secular equilibrium state between {sup 226}Ra and {sup 222}Rn in the common sample bottle. However, this direct measurement also has difficulties about the interference with a full energy absorption peak of 185.7 keV from {sup 235}U. In this study, direct measurement with the interference correction technique, which uses several reference peaks for gamma-rays from {sup 235}U and {sup 234}Th, and indirect measurement, which means the identification of {sup

  1. MASS SPECTROMETRIC ANALYSIS FOR THE IDENTIFICATION OF THUNNUS GENUS FOUR SPECIES

    Directory of Open Access Journals (Sweden)

    T. Pepe

    2011-01-01

    Full Text Available An accurate identification of similar fish species is necessary to prevent illegal substitution and is imposed by labeling regulations in UE countries (1. The genus Thunnus comprises many species of different quality and commercial value. The increasing trade of fish preparations of the species included in this genus and the consequent loss of the external anatomical and morphological features enables fraudulent substitutions. This study reports data relating to the proteomic analysis of four tuna species (T. thynnus, T. alalunga, T. albacares, T. obesus. Sarcoplasmic proteins were studied by mono and two dimensional electrophoresis. The most significant proteins for the characterization of the species were analyzed by mass spectrometric techniques. As reported in a previous study (2, an accurate identification of the species seems possible, owing to the polymorphism displayed by the species of the Thunnus genus.

  2. Development of an automated sequential injection on-line solvent extraction-back extraction procedure as demonstrated for the determination of cadmium with detection by electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Wang, Jianhua; Hansen, Elo Harald

    2002-01-01

    An automated sequential injection (SI) on-line solvent extraction-back extraction separation/preconcentration procedure is described. Demonstrated for the assay of cadmium by electrothermal atomic absorption spectrometry (ETAAS), the analyte is initially complexed with ammonium pyrrolidinedithioc......An automated sequential injection (SI) on-line solvent extraction-back extraction separation/preconcentration procedure is described. Demonstrated for the assay of cadmium by electrothermal atomic absorption spectrometry (ETAAS), the analyte is initially complexed with ammonium....../preconcentration process of the ensuing sample. An enrichment factor of 21.4, a detection limit of 2.7 ng/l, along with a sampling frequency of 13s/h were obtained at a sample flow rate of 6.0mlmin/sup -1/. The precision (R.S.D.) at the 0.4 mug/l level was 1.8% as compared to 3.2% when quantifying the organic extractant...

  3. Tunable diode laser absorption spectroscopy as method of choice for non-invasive and automated detection of microbial growth in media fills.

    Science.gov (United States)

    Brueckner, David; Roesti, David; Zuber, Ulrich; Sacher, Meik; Duncan, Derek; Krähenbühl, Stephan; Braissant, Olivier

    2017-05-15

    Tunable diode laser absorption spectroscopy (TDLAS) was evaluated on its potential to detect bacterial growth of contaminated media fill vials. The target was a replacement/ automation of the traditional visual media fill inspection. TDLAS was used to determine non-invasively O 2 and/or CO 2 changes in headspaces of such vials being induced by metabolically active microorganisms. Four different vial formats, 34 microorganisms (inoculation volume<10 cells) and two different media (TSB/FTM) were tested. Applying parallel CO 2 and O 2 headspace measurements all format-organism combinations were detected within <11 days reliably with reproducible results. False negatives were exclusively observed for samples that were intentionally breached with syringes of 0.3mm in diameter. Overall it was shown that TDLAS functionality for a replacement of the visual media fill inspection is given and that investing in further validation and implementation studies is valuable. Nevertheless, some small but vincible challenges remain to have this technology in practical use. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Optically detected X-ray absorption spectroscopy measurements as a means of monitoring corrosion layers on copper.

    Science.gov (United States)

    Dowsett, Mark G; Adriaens, Annemie; Jones, Gareth K C; Poolton, Nigel; Fiddy, Steven; Nikitenko, Sergé

    2008-11-15

    XANES and EXAFS information is conventionally measured in transmission through the energy-dependent absorption of X-rays or by observing X-ray fluorescence, but secondary fluorescence processes, such as the emission of electrons and optical photons (e.g., 200-1000 nm), can also be used as a carrier of the XAS signatures, providing complementary information such as improved surface specificity. Where the near-visible photons have a shorter range in a material, the data will be more surface specific. Moreover, optical radiation may escape more readily than X-rays through liquid in an environmental cell. Here, we describe a first test of optically detected X-ray absorption spectroscopy (ODXAS) for monitoring electrochemical treatments on copper-based alloys, for example, heritage metals. Artificially made corrosion products deposited on a copper substrate were analyzed in air and in a 1% (w/v) sodium sesquicarbonate solution to simulate typical conservation methods for copper-based objects recovered from marine environments. The measurements were made on stations 7.1 and 9.2 MF (SRS Daresbury, UK) using the mobile luminescence end station (MoLES), supplemented by XAS measurements taken on DUBBLE (BM26 A) at the ESRF. The ODXAS spectra usually contain fine structure similar to that of XAS spectra measured in X-ray fluorescence. Importantly, for the compounds examined, the ODXAS is significantly more surface specific, and >98% characteristic of thin surface layers of 0.5-1.5-microm thickness in cases where X-ray measurements are dominated by the substrate. However, EXAFS and XANES from broadband optical measurements are superimposed on a high background due to other optical emission modes. This produces statistical fluctuations up to double what would be expected from normal counting statistics because the data retain the absolute statistical fluctuation in the original raw count, while losing up to 70% of their magnitude when background is removed. The problem may be

  5. Comparison of electrothermal atomization diode laser Zeeman- and wavelength-modulated atomic absorption and coherent forward scattering spectrometry

    International Nuclear Information System (INIS)

    Blecker, Carlo R.; Hermann, Gerd M.

    2009-01-01

    Atomic absorption and coherent forward scattering spectrometry by using a near-infrared diode laser with and without Zeeman and wavelength modulation were carried out with graphite furnace electrothermal atomization. Analytical curves and limits of detection were compared. The magnetic field was modulated with 50 Hz, and the wavelength of the diode laser with 10 kHz. Coherent forward scattering was measured with crossed and slightly uncrossed polarizers. The results show that the detection limits of atomic absorption spectrometry are roughly the same as those of coherent forward scattering spectrometry with crossed polarizers. According to the theory with bright flicker noise limited laser sources the detection limits and linear ranges obtained with coherent forward scattering spectrometry with slightly uncrossed polarizers are significantly better than those obtained with crossed polarizers and with atomic absorption spectrometry. This is due to the fact that employing approaches of polarization spectroscopy reduce laser intensity fluctuations to their signal carried fractions

  6. Review on absorption technology with emphasis on small capacity absorption machines

    Directory of Open Access Journals (Sweden)

    Labus Jerko M.

    2013-01-01

    Full Text Available The aim of this paper is to review the past achievements in the field of absorption systems, their potential and possible directions for future development. Various types of absorption systems and research on working fluids are discussed in detail. Among various applications, solar cooling and combined cooling, heating and power (CCHP are identified as two most promising applications for further development of absorption machines. Under the same framework, special attention is given to the small capacity absorption machines and their current status at the market. Although this technology looks promising, it is still in development and many issues are open. With respect to that fact, this paper covers all the relevant aspects for further development of small capacity absorption machines.

  7. Absorption-line detections of 10{sup 5}-10{sup 6} K gas in spiral-rich groups of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Stocke, John T.; Keeney, Brian A.; Danforth, Charles W.; Syphers, David; Yamamoto, H.; Shull, J. Michael; Green, James C.; Froning, Cynthia [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Savage, Blair D.; Wakker, Bart; Kim, Tae-Sun [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Ryan-Weber, Emma V.; Kacprzak, Glenn G., E-mail: john.stocke@colorado.edu [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, VIC 3122 (Australia)

    2014-08-20

    Using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, the COS Science Team has conducted a high signal-to-noise survey of 14 bright QSOs. In a previous paper, these far-UV spectra were used to discover 14 'warm' (T ≥ 10{sup 5} K) absorbers using a combination of broad Lyα and broad O VI absorptions. A reanalysis of a few of this new class of absorbers using slightly relaxed fitting criteria finds as many as 20 warm absorbers could be present in this sample. A shallow, wide spectroscopic galaxy redshift survey has been conducted around these sight lines to investigate the warm absorber environment, which is found to be spiral-rich groups or cluster outskirts with radial velocity dispersions σ = 250-750 km s{sup –1}. While 2σ evidence is presented favoring the hypothesis that these absorptions are associated with the galaxy groups and not with the individual, nearest galaxies, this evidence has considerable systematic uncertainties and is based on a small sample size so it is not entirely conclusive. If the associations are with galaxy groups, the observed frequency of warm absorbers (dN/dz = 3.5-5 per unit redshift) requires them to be very extended as an ensemble on the sky (∼1 Mpc in radius at high covering factor). Most likely these warm absorbers are interface gas clouds whose presence implies the existence of a hotter (T ∼ 10{sup 6.5} K), diffuse, and probably very massive (>10{sup 11} M {sub ☉}) intra-group medium which has yet to be detected directly.

  8. Radioisotope studies for quantitative measurement of manganese absorption

    International Nuclear Information System (INIS)

    Helbig, U.

    1981-01-01

    Purpose of the present study was to quantitatively determine the manganese absorption in growing rats by means of radioisotopes. First of all the following factors had to be investigated, which are significant for this determination: Measurability of stable and radioactive Mn in rat tissues; labelling of stable Mn and distribution of stable and radioactive Mn in the organism; verification of the isotope dilution method and of the comparative balance method with regard to its applicability for the determination of the true Mn absorption. We useed male and female Sprague-Dawley rats. The most important results are summarized in the following: in some separate tissues measurement of stable Mn was accompanied by difficulties. The measurement of radioactive Mn however, could be performed without any problems. 10 d after i.m. injection of 54 Mn only 17% of the administered Mn was still detectable in the organism. However, there was no uniform tissue labelling found. Therefore it is possible to an only restricted extent to draw quantitative conclusions on the content of stable Mn. A high percentage of stable and radioactive Mn was found above all in the liver. The isotope dilution method permits by feces analysis to differentiate between unabsorbed Mn coming from the food and endogenic Mn coming from the organism itself. The effective Mn absorption was also determined by means of the comparative balance method. By means of the isotope dilution method we determined the quantitative Mn-absorption with staged Mn administration and the contribution of absorption and excretion to the homeostatic regulation mechanisms of Mn. We found that absorption and excretion help the organism to keep an almost constant Mn concentration even with a differing Mn supply. (orig./MG) [de

  9. Upper limits for absorption by water vapor in the near-UV

    International Nuclear Information System (INIS)

    Wilson, Eoin M.; Wenger, John C.; Venables, Dean S.

    2016-01-01

    There are few experimental measurements of absorption by water vapor in the near-UV. Here we report the results of spectral measurements of water vapor absorption at ambient temperature and pressure from 325 nm to 420 nm, covering most tropospherically relevant short wavelengths. Spectra were recorded using a broadband optical cavity in the chemically controlled environment of an atmospheric simulation chamber. No absorption attributable to the water monomer (or the dimer) was observed at the 0.5 nm resolution of our system. Our results are consistent with calculated spectra and recent DOAS field observations, but contradict a report of significant water absorption in the near-UV. Based on the detection limit of our instrument, we report upper limits for the water absorption cross section of less than 5×10 −26 cm 2 molecule −1 at our instrument resolution. For a typical, indicative slant column density of 4×10 23 cm 2 , we calculate a maximum optical depth of 0.02 arising from absorption of water vapor in the atmosphere at wavelengths between 340 nm and 420 nm, with slightly higher maximum optical depths below 340 nm. The results of this work, together with recent atmospheric observations and computational results, suggest that water vapor absorption across most of the near-UV is small compared to visible and infrared wavelengths. - Highlights: • The absorption cross section of water vapor was studied from 325 to 420 nm. • The upper limit was 5×10 −26 cm 2 molecule −1 above 340 nm at 0.5 nm resolution. • Our result contradicts a recent report of appreciable absorption by water vapor.

  10. Spectroscopic study of low-temperature hydrogen absorption in palladium

    Energy Technology Data Exchange (ETDEWEB)

    Ienaga, K., E-mail: ienaga@issp.u-tokyo.ac.jp; Takata, H.; Onishi, Y.; Inagaki, Y.; Kawae, T. [Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Motooka, Nishi-Ku, Fukuoka 819-0395 (Japan); Tsujii, H. [Department of Physics, Faculty of Education, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Kimura, T. [Department of Physics, Kyushu University, Hakozaki, Higashi-Ku, Fukuoka 812-8581 (Japan)

    2015-01-12

    We report real-time detection of hydrogen (H) absorption in metallic palladium (Pd) nano-contacts immersed in liquid H{sub 2} using inelastic electron spectroscopy (IES). After introduction of liquid H{sub 2}, the spectra exhibit the time evolution from the pure Pd to the Pd hydride, indicating that H atoms are absorbed in Pd nano-contacts even at the temperature where the thermal process is not expected. The IES time and bias voltage dependences show that H absorption develops by applying bias voltage 30 ∼ 50 mV, which can be explained by quantum tunneling. The results represent that IES is a powerful method to study the kinetics of high density H on solid surface.

  11. Experimental and clinical studies on simultaneous fat and protein tolerance digestion-absorption test using 131I-triolein and 125I-RISA

    International Nuclear Information System (INIS)

    Tokura, Yasunobu

    1979-01-01

    Simultaneous fat and protein tolerance digestion-absorption test using 131 I-triolein and 125 I-RISA was investigated experimentally in rats and clinically in 148 inpatients with various diseases. The results were as follows: Animal experiments. Fat absorption was markedly impaired in the exclusion of bile from the intestine. Each function of fat and protein absorption was independently detected. These animal experiments gave the clinical evaluation of this test for fat and protein digestion-absorption function. Clinical investigations. The test meal was prepared without using commercial Tween 80 as an emulgent. Either fat or protein absorption was markedly impaired in some patients with various diseases. Inpatients with various diseases investigated were divided into 3 groups by correlation coefficient between fecal excretion ratios of fat and protein. Each function of fat and protein digestion-absorption was able to be detected independently by this test simultaneously. This test can further be used as a labolatory aid in evaluating fat and protein digestion-absorption function in patients with malabsorption syndrome. (author)

  12. Determination of Cd in urine by cloud point extraction-tungsten coil atomic absorption spectrometry.

    Science.gov (United States)

    Donati, George L; Pharr, Kathryn E; Calloway, Clifton P; Nóbrega, Joaquim A; Jones, Bradley T

    2008-09-15

    Cadmium concentrations in human urine are typically at or below the 1 microgL(-1) level, so only a handful of techniques may be appropriate for this application. These include sophisticated methods such as graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry. While tungsten coil atomic absorption spectrometry is a simpler and less expensive technique, its practical detection limits often prohibit the detection of Cd in normal urine samples. In addition, the nature of the urine matrix often necessitates accurate background correction techniques, which would add expense and complexity to the tungsten coil instrument. This manuscript describes a cloud point extraction method that reduces matrix interference while preconcentrating Cd by a factor of 15. Ammonium pyrrolidinedithiocarbamate and Triton X-114 are used as complexing agent and surfactant, respectively, in the extraction procedure. Triton X-114 forms an extractant coacervate surfactant-rich phase that is denser than water, so the aqueous supernatant is easily removed leaving the metal-containing surfactant layer intact. A 25 microL aliquot of this preconcentrated sample is placed directly onto the tungsten coil for analysis. The cloud point extraction procedure allows for simple background correction based either on the measurement of absorption at a nearby wavelength, or measurement of absorption at a time in the atomization step immediately prior to the onset of the Cd signal. Seven human urine samples are analyzed by this technique and the results are compared to those found by the inductively coupled plasma mass spectrometry analysis of the same samples performed at a different institution. The limit of detection for Cd in urine is 5 ngL(-1) for cloud point extraction tungsten coil atomic absorption spectrometry. The accuracy of the method is determined with a standard reference material (toxic metals in freeze-dried urine) and the determined values agree with

  13. Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chen Li [Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen (Germany); Ueta, Hirokazu; Beck, Rainer D. [Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne (Switzerland); Bisson, Regis [Aix-Marseille Universite, PIIM, CNRS, UMR 7345, 13397 Marseille (France)

    2013-05-15

    We report the design and characterization of a new molecular-beam/surface-science apparatus for quantum state-resolved studies of gas/surface reaction dynamics combining optical state-specific reactant preparation in a molecular beam by rapid adiabatic passage with detection of surface-bound reaction products by reflection absorption infrared spectroscopy (RAIRS). RAIRS is a non-invasive infrared spectroscopic detection technique that enables online monitoring of the buildup of reaction products on the target surface during reactant deposition by a molecular beam. The product uptake rate obtained by calibrated RAIRS detection yields the coverage dependent state-resolved reaction probability S({theta}). Furthermore, the infrared absorption spectra of the adsorbed products obtained by the RAIRS technique provide structural information, which help to identify nascent reaction products, investigate reaction pathways, and determine branching ratios for different pathways of a chemisorption reaction. Measurements of the dissociative chemisorption of methane on Pt(111) with this new apparatus are presented to illustrate the utility of RAIRS detection for highly detailed studies of chemical reactions at the gas/surface interface.

  14. Folate absorption

    International Nuclear Information System (INIS)

    Baker, S.J.

    1976-01-01

    Folate is the generic term given to numerous compounds of pteroic acid with glutamic acid. Knowledge of absorption is limited because of the complexities introduced by the variety of compounds and because of the inadequacy of investigational methods. Two assay methods are in use, namely microbiological and radioactive. Techniques used to study absorption include measurement of urinary excretion, serum concentration, faecal excretion, intestinal perfusion, and haematological response. It is probably necessary to test absorption of both pteroylmonoglutamic acid and one or more polyglutamates, and such tests would be facilitated by availability of synthesized compounds labelled with radioactive tracers at specifically selected sites. (author)

  15. Topic model-based mass spectrometric data analysis in cancer biomarker discovery studies.

    Science.gov (United States)

    Wang, Minkun; Tsai, Tsung-Heng; Di Poto, Cristina; Ferrarini, Alessia; Yu, Guoqiang; Ressom, Habtom W

    2016-08-18

    A fundamental challenge in quantitation of biomolecules for cancer biomarker discovery is owing to the heterogeneous nature of human biospecimens. Although this issue has been a subject of discussion in cancer genomic studies, it has not yet been rigorously investigated in mass spectrometry based proteomic and metabolomic studies. Purification of mass spectometric data is highly desired prior to subsequent analysis, e.g., quantitative comparison of the abundance of biomolecules in biological samples. We investigated topic models to computationally analyze mass spectrometric data considering both integrated peak intensities and scan-level features, i.e., extracted ion chromatograms (EICs). Probabilistic generative models enable flexible representation in data structure and infer sample-specific pure resources. Scan-level modeling helps alleviate information loss during data preprocessing. We evaluated the capability of the proposed models in capturing mixture proportions of contaminants and cancer profiles on LC-MS based serum proteomic and GC-MS based tissue metabolomic datasets acquired from patients with hepatocellular carcinoma (HCC) and liver cirrhosis as well as synthetic data we generated based on the serum proteomic data. The results we obtained by analysis of the synthetic data demonstrated that both intensity-level and scan-level purification models can accurately infer the mixture proportions and the underlying true cancerous sources with small average error ratios (data, we found more proteins and metabolites with significant changes between HCC cases and cirrhotic controls. Candidate biomarkers selected after purification yielded biologically meaningful pathway analysis results and improved disease discrimination power in terms of the area under ROC curve compared to the results found prior to purification. We investigated topic model-based inference methods to computationally address the heterogeneity issue in samples analyzed by LC/GC-MS. We observed

  16. Theoretical study and construction of a multichannel {beta} spectrometer with uniform magnetic field; Etude et realisation d'un spectrometre {beta} multivoies a champ magnetique uniforme

    Energy Technology Data Exchange (ETDEWEB)

    Schussler, F [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-09-01

    After a brief survey of the interest of a multichannel beta spectrometer for studying decay schemes of short lived nuclides (30 seconds minimum, the theoretically well known characteristics of uniform magnetic field analyser (image of a large source, transmission and resolution) are briefly remembered. In the second part, the apparatus built as a result of these calculations is described. This apparatus allows the determination of beta spectra by simultaneous determination of the beta spectra in coincidence with four gamma rays predetermined in the gamma spectrum of the studied nuclide. Finally, in the last part, the experimental characteristics of the spectrometer (calibration in energy and transmission) and the first measurement of beta spectra ({sup 155}Sm) and of coincidences ({sup 24}Na), are given. (author) [French] Apres avoir brievement souligne l'interet pratique que presente un spectrometre multivoies pour l'etude des schemas de desintegration des corps radioactifs de courtes periodes (30 secondes au maximum), l'auteur effectue un rappel des caracteristiques theoriques bien connues d'un analyseur magnetique a champ uniforme (image d'une source etendue) calcul de la transmission et du pouvoir de resolution. Une deuxieme partie est consacree a la description de l'appareil realise d'apres ces calculs. Cet appareil permet le releve des spectres beta par detection, simultanee de dix groupes d'electrons d'energies differentes; il permet egalement le releve simultane des spectres beta en coincidence avec quatre rayonnements gammas preselectionnes a l'avance dans le spectre gamma du corps etudie. Dans une derniere partie enfin, sont donnees les caracteristiques experimentales du spectrometre (etalonnage en energie et en transmission) ainsi que les premiers resultats des etudes de spectre beta ({sup 155}Sm) et de coincidence ({sup 24}Na). (auteur)

  17. In-source collision induced dissociation of inorganic explosives for mass spectrometric signature detection and chemical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, Thomas P., E-mail: thomas.forbes@nist.gov; Sisco, Edward

    2015-09-10

    The trace detection, bulk quantification, and chemical imaging of inorganic explosives and components was demonstrated utilizing in-source collision induced dissociation (CID) coupled with laser desorption/ionization mass spectrometry (LDI-MS). The incorporation of in-source CID provided direct control over the extent of adduct and cluster fragmentation as well as organic noise reduction for the enhanced detection of both the elemental and molecular ion signatures of fuel-oxidizer mixtures and other inorganic components of explosive devices. Investigation of oxidizer molecular anions, specifically, nitrates, chlorates, and perchlorates, identified that the optimal in-source CID existed at the transition between fragmentation of the ionic salt bonds and molecular anion bonds. The chemical imaging of oxidizer particles from latent fingerprints was demonstrated, including both cation and anion components in positive and negative mode mass spectrometry, respectively. This investigation demonstrated LDI-MS with in-source CID as a versatile tool for security fields, as well as environmental monitoring and nuclear safeguards, facilitating the detection of elemental and molecular inorganic compounds at nanogram levels. - Highlights: • In-source CID enhanced detection of elemental inorganics up to 1000-fold. • In-source CID optimization of polyatomic oxidizers enhanced detection up to 100-fold. • Optimal CID identified at transition from breaking ionic salt to molecular anion bonds. • Trace detection of inorganic explosives at nanogram levels was demonstrated. • Oxidizer particles were chemically imaged directly from latent fingerprints.

  18. Synergetic enhancement effect of ionic liquid and diethyldithiocarbamate on the chemical vapor generation of nickel for its atomic fluorescence spectrometric determination in biological samples

    International Nuclear Information System (INIS)

    Zhang Chuan; Li Yan; Wu Peng; Yan Xiuping

    2009-01-01

    Room-temperature ionic liquid in combination with sodium diethyldithiocarbamate (DDTC) was used to synergetically improve the chemical vapor generation (CVG) of nickel. Volatile species of nickel were effectively generated through reduction of acidified analyte solution with KBH 4 in the presence of 0.02% DDTC and 25 mmol L -1 1-butyl-3-methylimidazolium bromide ([C 4 mim]Br) at room temperature. Thus, a new flow injection (FI)-CVG-atomic fluorescence spectrometric (FI-CVG-AFS) method was developed for determination of nickel with a detection limit of 0.65 μg L -1 (3 s) and a sampling frequency of 180 h -1 . With consumption of 0.5 mL sample solution, an enhancement factor of 2400 was obtained. The precision (RSD) for eleven replicate determinations of 20 μg L -1 Ni was 3.4%. The developed FI-CVG-AFS method was successfully applied to determination of trace Ni in several certified biological reference materials.

  19. The study on the lidar's detection limit for Iodine Gas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-lyul; Baik, Seung-Hoon; Park, Seung-Kyu; Park, Nak-Gyu; Ahn, Yong-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    A powerful and reliable tool for range-resolved remote sensing of gas concentrations that has proven its capabilities in a variety of studies is the differential absorption lidar (DIAL). Differential absorption lidar (DIAL) is frequently used for atmospheric gas monitoring to detect impurities such as nitrogen dioxide, sulfur dioxide, iodine, and ozone. DIAL can measure air pollutant concentrations with a high spatial resolution by adopting two laser systems with different degrees of absorption between the two different wavelengths. The absorption of the reference wavelength is very weak, while the absorption of the other wavelength is very strong. In this paper, we measured the limit of detection capability of our designed DIAL system. The DIAL measurements were performed using a target iodine cell in the laboratory. We confirmed that the concentration of iodine gas ratio increased after the laser passed through the iodine cell. The system of DIAL(Differential Absorption Lidar) was effective to detect the iodine gas. We obtained the signals from the iodine target cell and the lidar signal from the iodine target cell was proportional to frequency locking ratios.

  20. X-ray absorption fine structure (XAFS) studies of cobalt silicide thin films

    International Nuclear Information System (INIS)

    Naftel, S.J.; Coulthard, I.; Hu, Y.; Sham, T.K.; Zinke-Allmang, M.

    1998-01-01

    Cobalt silicide thin films, prepared on Si(100) wafers, have been studied by X-ray absorption near edge structures (XANES) at the Si K-, L 2,3 - and Co K-edges utilizing both total electron (TEY) and fluorescence yield (FLY) detection as well as extended X-ray absorption fine structure (EXAFS) at the Co K-edge. Samples made using DC sputter deposition on clean Si surfaces and MBE were studied along with a bulk CoSi 2 sample. XANES and EXAFS provide information about the electronic structure and morphology of the films. It was found that the films studied have essentially the same structure as bulk CoSi 2 . Both the spectroscopy and materials characterization aspects of XAFS (X-ray absorption fine structures) are discussed

  1. [Gastric cancer detection using kubelka-Munk spectral function of DNA and protein absorption bands].

    Science.gov (United States)

    Li, Lan-quan; Wei, Hua-jiang; Guo, Zhou-yi; Yang, Hong-qin; Xie, Shu-sen; Chen, Xue-mei; Li, Li-bo; He, Bol-hua; Wu, Guo-yong; Lu, Jian-jun

    2009-09-01

    Differential diagnosis for epithelial tissues of normal human gastric, undifferentiation gastric adenocarcinoma, gastric squamous cell carcinomas, and poorly differentiated gastric adenocarcinoma were studied using the Kubelka-Munk spectral function of the DNA and protein absorption bands at 260 and 280 nm in vitro. Diffuse reflectance spectra of tissue were measured using a spectrophotometer with an integrating sphere attachment. The results of measurement showed that for the spectral range from 250 to 650 nm, pathological changes of gastric epithelial tissues induced that there were significant differences in the averaged value of the Kubelka-Munk function f(r infinity) and logarithmic Kubelka-Munk function log[f(r infinity)] of the DNA absorption bands at 260 nm between epithelial tissues of normal human stomach and human undifferentiation gastric cancer, between epithelial tissues of normal human stomach and human gastric squamous cell carcinomas, and between epithelial tissues of normal human stomach and human poorly differentiated cancer. Their differences were 68.5% (p function f(r infinity) and logarithmic Kubelka-Munk function log[f(r infinity)] of the protein absorption bands at 280 nm between epithelial tissues of normal human stomach and human undifferentiation gastric cancer, between epithelial tissues of normal human stomach and human gastric squamous cell carcinomas, and between epithelial tissues of normal human stomach and human poorly differentiated cancer. Their differences were 86.8% (p function f(r infinity) and logarithmic Kubelka-Munk function log[f(r infinity)] of the carotene absorption bands at 480 nm between epithelial tissues of normal human stomach and human undifferentiation gastric cancer, between epithelial tissues of normal human stomach and human gastric squamous cell carcinomas, and between epithelial tissues of normal human stomach and human poorly differentiated cancer. Their differences were 59.5% (p < 0.05), 73% (p < 0

  2. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    Directory of Open Access Journals (Sweden)

    Ming Dong

    2017-11-01

    Full Text Available Sulfur hexafluoride (SF6 gas-insulated electrical equipment is widely used in high-voltage (HV and extra-high-voltage (EHV power systems. Partial discharge (PD and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF6 decomposition products, and electrochemical sensing (ES and infrared (IR spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF6 gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF6 decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF6 gas decomposition and is verified to reliably and accurately detect the gas components and concentrations.

  3. Electrochemical and Infrared Absorption Spectroscopy Detection of SF6 Decomposition Products

    Science.gov (United States)

    Dong, Ming; Ren, Ming; Ye, Rixin

    2017-01-01

    Sulfur hexafluoride (SF6) gas-insulated electrical equipment is widely used in high-voltage (HV) and extra-high-voltage (EHV) power systems. Partial discharge (PD) and local heating can occur in the electrical equipment because of insulation faults, which results in SF6 decomposition and ultimately generates several types of decomposition products. These SF6 decomposition products can be qualitatively and quantitatively detected with relevant detection methods, and such detection contributes to diagnosing the internal faults and evaluating the security risks of the equipment. At present, multiple detection methods exist for analyzing the SF6 decomposition products, and electrochemical sensing (ES) and infrared (IR) spectroscopy are well suited for application in online detection. In this study, the combination of ES with IR spectroscopy is used to detect SF6 gas decomposition. First, the characteristics of these two detection methods are studied, and the data analysis matrix is established. Then, a qualitative and quantitative analysis ES-IR model is established by adopting a two-step approach. A SF6 decomposition detector is designed and manufactured by combining an electrochemical sensor and IR spectroscopy technology. The detector is used to detect SF6 gas decomposition and is verified to reliably and accurately detect the gas components and concentrations. PMID:29140268

  4. Mass Spectrometric Detection of Botulinum Neurotoxin by Measuring its Activity in Serum and Milk

    Science.gov (United States)

    Kalb, Suzanne R.; Pirkle, James L.; Barr, John R.

    Botulinum neurotoxins (BoNTs) are bacterial protein toxins which are considered likely agents for bioterrorism due to their extreme toxicity and high availability. A new mass spectrometry based assay called Endopep MS detects and defines the toxin serotype in clinical and food matrices via toxin activity upon a peptide substrate which mimics the toxin's natural target. Furthermore, the subtype of the toxin is differentiated by employing mass spectrometry based proteomic techniques on the same sample. The Endopep-MS assay selectively detects active BoNT and defines the serotype faster and with sensitivity greater than the mouse bioassay. One 96-well plate can be analyzed in under 7 h. On higher level or "hot" samples, the subtype can then be differentiated in less than 2 h with no need for DNA.

  5. Study of semi-conductor spectrometers for high counting rates. Application to the study of the reaction {sup 31}P (p, {alpha}{sub 0}): E{sub p} < 2 MeV; Etude de spectrometres a semi-conducteurs pour forts taux de comptage application a l'etude de la reaction {sup 31}P (p, {alpha}0): E{sub p} < 2 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Ligeon, E [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

    1967-10-01

    The study of nuclear reactions involving particles of low charge (E < 2 MeV) calls for spectrometers of high resolving power. In many experiments however, the counting rate is high because of Coulomb scattering at the target: this results in a distortion of the experimental spectra and a loss of resolving power in the detection equipment. The first part of the work is devoted to an evaluation of the resolving power obtained with silicon-detector spectrometers. A study of the elastic scattering of protons by {sup 31}P shows which are the factors limiting the resolving power. In the second part we examine the various types of spectrometer which can be used in the case of a high count-rate. We have built an apparatus which can be used for carrying out spectrometry on particles produced by nuclear reactions, for a total, count-rate of 10{sup 5} counts/sec. (author) [French] L'etude des reactions nucleaires avec particules chargees a basse energie (E < 2 MeV) exige des spectrometres de haute resolution. Cependant, dans de nombreuses experiences le taux de comptage est eleve, par suite de la diffusion coulombienne sur la cible; on observe alors une distorsion des spectres experimentaux et une perte de resolution de l'ensemble de detection. La premiere partie de ce travail est consacree a l'evaluation de la resolution obtenue avec des spectrometres utilisant des detecteurs au silicium. L'etude de la diffusion elastique des protons sur le {sup 31}P montre quels sont les facteurs qui limitent la resolution. Dans une deuxieme partie, nous etudions les differents types de spectrometres que l'on peut utiliser dans le cas d'un taux de comptage eleve. Nous avons construit un appareil qui permet de faire la spectrometrie de particules, provenant de reactions nucleaires, pour un taux de comptage total de 10{sup 5} c/s. (auteur)

  6. [Absorption Characteristics and Simulation of LLM-105 in the Terahertz Range].

    Science.gov (United States)

    Meng, Zeng-rui; Shang, Li-ping; Du, Yu; Deng, Hu

    2015-07-01

    2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), a novel explosive with high energy and low sensibility. In order to study the molecular structure characteristics of the explosive, the absorption spectra of LLM-105 in the frequency range of 0.2-2.4 THz were detected by terahertz time-domain spectroscopy (THz-TDS). The results showed that a number of characteristic absorption peaks with different intensity located at 1.27, 1.59, 2.00, 2.08, 2.20, 2.29 THz. The article also simulated the absorption spectra of LLM-105 molecular crystal within 0.2-2.5 THz region by using Materials Studio 6.0 software based on density functional theory (DFT), and the simulated results agreed well with the experimental data except for the peak at 2.29 THz, which verified theoretically the accuracy of the experimental data. In addition, the vibrational modes of the characteristic peaks in the experimental absorption spectra were analyzed and identified, the results showed that the forming of the characteristic absorption peaks and the molecular vibration were closely related, which further provided important laboratory and technology support for the study of the transformation of molecule structure of LLM-105. There was no simulated frequency agreed with the experimental absorption peak at 2.29 THz, which may be caused by the vibration of the crystal lattice or other reasons.

  7. Application of extraction-chromatographic concentration to atomic absorption determination of lead and cadmium in drinking and sea water

    International Nuclear Information System (INIS)

    Bol'shova, T.A.; Agapkina, G.I.; Ershova, N.I.; Narankho, K.E.

    1988-01-01

    To increase the detection limits for lead and cadmium atomic-absorption determination in natural waters methods of extraction-chromatographic concentration of these metals using tri-n-octylamine (TOA) on polytetrafluoroethylene (PTFE) is developed. Chromatograpy was carried out from 1.5-2.0 M HBr solutions. For cadmium and lead elution acetic acid was used. It is shown that extraction-chromatographic concentration permits to decrease limits of metal atomic-absorption detection by 10 3 with the 500 ml volume sample analysis

  8. Impurity profiling of liothyronine sodium by means of reversed phase HPLC, high resolution mass spectrometry, on-line H/D exchange and UV/Vis absorption.

    Science.gov (United States)

    Ruggenthaler, M; Grass, J; Schuh, W; Huber, C G; Reischl, R J

    2017-09-05

    For the first time, a comprehensive investigation of the impurity profile of the synthetic thyroid API (active pharmaceutical ingredient) liothyronine sodium (LT 3 Na) was performed by using reversed phase HPLC and advanced structural elucidation techniques including high resolution tandem mass spectrometry (HRMS/MS) and on-line hydrogen-deuterium (H/D) exchange. Overall, 39 compounds were characterized and 25 of these related substances were previously unknown to literature. The impurity classification system recently developed for the closely related API levothyroxine sodium (LT 4 Na) could be applied to the newly characterized liothyronine sodium impurities resulting in a wholistic thyroid API impurity classification system. Furthermore, the mass-spectrometric CID-fragmentation of specific related substances was discussed and rationalized by detailed fragmentation pathways. Moreover, the UV/Vis absorption characteristics of the API and selected impurities were investigated to corroborate chemical structure assignments derived from MS data. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. OpenChrom: a cross-platform open source software for the mass spectrometric analysis of chromatographic data.

    Science.gov (United States)

    Wenig, Philip; Odermatt, Juergen

    2010-07-30

    Today, data evaluation has become a bottleneck in chromatographic science. Analytical instruments equipped with automated samplers yield large amounts of measurement data, which needs to be verified and analyzed. Since nearly every GC/MS instrument vendor offers its own data format and software tools, the consequences are problems with data exchange and a lack of comparability between the analytical results. To challenge this situation a number of either commercial or non-profit software applications have been developed. These applications provide functionalities to import and analyze several data formats but have shortcomings in terms of the transparency of the implemented analytical algorithms and/or are restricted to a specific computer platform. This work describes a native approach to handle chromatographic data files. The approach can be extended in its functionality such as facilities to detect baselines, to detect, integrate and identify peaks and to compare mass spectra, as well as the ability to internationalize the application. Additionally, filters can be applied on the chromatographic data to enhance its quality, for example to remove background and noise. Extended operations like do, undo and redo are supported. OpenChrom is a software application to edit and analyze mass spectrometric chromatographic data. It is extensible in many different ways, depending on the demands of the users or the analytical procedures and algorithms. It offers a customizable graphical user interface. The software is independent of the operating system, due to the fact that the Rich Client Platform is written in Java. OpenChrom is released under the Eclipse Public License 1.0 (EPL). There are no license constraints regarding extensions. They can be published using open source as well as proprietary licenses. OpenChrom is available free of charge at http://www.openchrom.net.

  10. Thermodynamic performance optimization of the absorption-generation process in an absorption refrigeration cycle

    International Nuclear Information System (INIS)

    Chen, Yi; Han, Wei; Jin, Hongguang

    2016-01-01

    Highlights: • This paper proposes a new thermal compressor model with boost pressure ratio. • The proposed model is an effective way to optimize the absorption-generation process. • Boost pressure ratio is a key parameter in the proposed thermal compressor model. • The optimum boost pressure ratios for two typical refrigeration systems are obtained. - Abstract: The absorption refrigeration cycle is a basic cycle that establishes the systems for utilizing mid-low temperature heat sources. A new thermal compressor model with a key parameter of boost pressure ratio is proposed to optimize the absorption-generation process. The ultimate generation pressure and boost pressure ratio are used to represent the potential and operating conditions of the thermal compressor, respectively. Using the proposed thermal compressor model, the operation mechanism and requirements of the absorption refrigeration system and absorption-compression refrigeration system are elucidated. Furthermore, the two typical heat conversion systems are optimized based on the thermal compressor model. The optimum boost pressure ratios of the absorption refrigeration system and the absorption-compression refrigeration system are 0.5 and 0.75, respectively. For the absorption refrigeration system, the optimum generation temperature is 125.31 °C at the cooling water temperature of 30 °C, which is obtained by simple thermodynamic calculation. The optimized thermodynamic performance of the absorption-compression refrigeration system is 16.7% higher than that of the conventional absorption refrigeration system when the generation temperature is 100 °C. The thermal compressor model proposed in this paper is an effective method for simplifying the optimization of the thermodynamic systems involving an absorption-generation process.

  11. Synchrotron radiation based Mössbauer absorption spectroscopy of various nuclides

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Ryo, E-mail: masudar@rri.kyoto-u.ac.jp; Kobayashi, Yasuhiro; Kitao, Shinji; Kurokuzu, Masayuki; Saito, Makina [Kyoto University, Research Reactor Institute (Japan); Yoda, Yoshitaka [Japan Synchrotron Radiation Research Institute, Resarch and Utilization Division (Japan); Mitsui, Takaya [Japan Atomic Energy Agency, Condensed Matter Science Division, Sector of Nuclear Science Research (Japan); Seto, Makoto [Kyoto University, Research Reactor Institute (Japan)

    2016-12-15

    Synchrotron-radiation (SR) based Mössbauer absorption spectroscopy of various nuclides is reviewed. The details of the measuring system and analysis method are described. Especially, the following two advantages of the current system are described: the detection of internal conversion electrons and the close distance between the energy standard scatterer and the detector. Both of these advantages yield the enhancement of the counting rate and reduction of the measuring time. Furthermore, SR-based Mössbauer absorption spectroscopy of {sup 40}K, {sup 151}Eu, and {sup 174}Yb is introduced to show the wide applicability of this method. In addition to these three nuclides, SR-based Mössbauer absorption spectroscopy of {sup 61}Ni, {sup 73}Ge, {sup 119}Sn, {sup 125}Te, {sup 127}I, {sup 149}Sm, and {sup 189}Os has been performed. We continue to develop the method to increase available nuclides and to increase its ease of use. The complementary relation between the time-domain method using SR, such as nuclear forward scattering and the energy-domain methods such as SR-based Mössbauer absorption spectroscopy is also noted.

  12. Constraining the Intergalactic and Circumgalactic Media with Lyman-Alpha Absorption

    Science.gov (United States)

    Sorini, Daniele; Onorbe, Jose; Hennawi, Joseph F.; Lukic, Zarija

    2018-01-01

    Lyman-alpha (Ly-a) absorption features detected in quasar spectra in the redshift range 02Mpc, the simulations asymptotically match the observations, because the ΛCDM model successfully describes the ambient IGM. This represents a critical advantage of studying the mean absorption profile. However, significant differences between the simulations, and between simulations and observations are present on scales 20kpc-2Mpc, illustrating the challenges of accurately modeling and resolving galaxy formation physics. It is noteworthy that these differences are observed as far out as ~2Mpc, indicating that the `sphere-of-influence' of galaxies could extend to approximately ~20 times the halo virial radius (~100kpc). Current observations are very precise on these scales and can thus strongly discriminate between different galaxy formation models. I demonstrate that the Ly-a absorption profile is primarily sensitive to the underlying temperature-density relationship of diffuse gas around galaxies, and argue that it thus provides a fundamental test of galaxy formation models. With near-future high-precision observations of Ly-a absorption, the tools developed in my thesis set the stage for even stronger constraints on models of galaxy formation and cosmology.

  13. Cavity Enhanced Absorption Spectroscopy in Air Pollution Monitoring

    Directory of Open Access Journals (Sweden)

    Janusz MIKOŁAJCZYK

    2015-10-01

    Full Text Available The paper presents some practical aspects of cavity enhanced absorption spectroscopy application in detection of nitrogen dioxide (NO2, nitrous oxide (N2O, nitric oxide (NO and carbon monoxide (CO. These gases are very important for monitoring of environment. There are shown results of lab-setups for N2O, NO, CO detection and portable sensor of NO2. The portable instrument operates in the UV spectral range and reaches a level of single ppb. The lab–devices use high precision mid-infrared spectroscopy and they was demonstrated during testing the laboratory air. These sensors are able to measure concentration at the ppb level using quantum cascade lasers, high quality optical cavities and modern MCT detection modules. It makes it possible to apply such sensors in monitoring the atmosphere quality.

  14. Effectiveness in detecting fission fragments with ionization chambers

    International Nuclear Information System (INIS)

    Manrique Garcia, J.; Monne, G.

    1991-01-01

    Detection of fission fragments is important in nuclear measurements. When a high detection accuracy is required it is necessary to take in account the detection losses due to the absorption of fragments in the fissionable material. The losses corrections might change the final results in 2-3%. The traditional expression used in the calculation of the detection efficiency does not consider neither the density variation of the fissionable substance with its width, because it depends on the target material. That's why actually in many labs it is being searched new methods that allow to find the efficiency for each target. In this work a new method for determination of absorption efficiency is presented. The obtained results are analyzed

  15. N-annulated perylene fused porphyrins with enhanced near-IR absorption and emission

    KAUST Repository

    Jiao, Chongjun; Huang, Kuo-Wei; Guan, Zhenping; Xu, Qinghua; Wu, Jishan

    2010-01-01

    -IR absorption, as well as detectable photoluminescence quantum yields, all of which are comparable to or even exceed those of either meso-β doubly linked porphyrin dimer/trimer or bis/tri-N-annulated rylenes. © 2010 American Chemical Society.

  16. OH detection by Ford Motor Company

    Science.gov (United States)

    Wang, Charles C.

    1986-12-01

    Two different methods for detection of OH are presented: a low pressure flow cell system and a frequency modulation absorption measurement. Using conventional absorption spectroscopy, detection limits were quoted of 1,000,000 OH molecules per cu cm using a 30-minute averaging time on the ground, and a 3-hour averaging time in the air for present apparatus in use. With the addition of FM spectroscopy at 1 GHz, a double-beam machine should permit detectable absorption of and an OH limit of 100,000 per cu cm in a 30-minute averaging time. In the low pressure system on which experiments are ongoing nonexponential time behavior was observed after the decay had progressed to about 0.3 of its original level; this was attributed to ion emission in the photomultiplier. A flame source with OH present at high concentration levels was used as a calibration. It was estimated that within the sampling chamber, 400,000 OH could be measured. With a factor-of-2 loss at the sampling orifice, this means detectability of 5 to 8 x 100,000 cu cm at the present time. This could be reduced by a factor of 2 in one hour averaging time; improvements in laser bandwidth and energy should provide another factor of 2 in sensitivity.

  17. A superheterodyne spectrometer for electronic paramagnetic. Resonance; Spectrometre superheterodyne de resonance paramagnetique electronique

    Energy Technology Data Exchange (ETDEWEB)

    Laffon, J L [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1963-12-15

    After a few generalities about electron paramagnetic resonance, a consideration of different experimental techniques authorises the choice of a particular type of apparatus. An EPR superheterodyne spectrometer built in the laboratory and having a novel circuit is described in detail. With this apparatus, many experimental results have been obtained and some of these are described as example. (author) [French] Apres quelques generalites sur le phenomene de resonance paramagnetique electronique, une synthese des differentes techniques experimentales, permet de fixer le choix d'un type d'appareillage. Un spectrometre de RPE superheterodyne realise en laboratoire et comportant un circuit original est expose dans le detail. Cet appareil a permis de nombreux resultats experimentaux dont quelques-uns sont decrits a titre d'exemple. (auteur)

  18. Intervening O vi Quasar Absorption Systems at Low Redshift: A Significant Baryon Reservoir.

    Science.gov (United States)

    Tripp; Savage; Jenkins

    2000-05-01

    Far-UV echelle spectroscopy of the radio-quiet QSO H1821+643 (zem=0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) at approximately 7 km s-1 resolution, reveals four definite O vi absorption-line systems and one probable O vi absorber at 0.15quasar in redshift; these are likely intervening systems unrelated to the background QSO. In the case of the strong O vi system at zabs=0.22497, multiple components are detected in Si iii and O vi as well as H i Lyman series lines, and the differing component velocity centroids and b-values firmly establish that this is a multiphase absorption system. A weak O vi absorber is detected at zabs=0.22637, i.e., offset by approximately 340 km s-1 from the zabs=0.22497 system. Lyalpha absorption is detected at zabs=0.22613, but no Lyalpha absorption is significantly detected at 0.22637. Other weak O vi absorbers at zabs=0.24531 and 0.26659 and the probable O vi system at 0.21326 have widely diverse O vi/H i column density ratios with N(O vi)/N(H i) ranging from

  19. Mass spectrometric analysis of electrophoretically separated allergens and proteases in grass pollen diffusates

    Directory of Open Access Journals (Sweden)

    Geczy Carolyn L

    2003-09-01

    Full Text Available Abstract Background Pollens are important triggers for allergic asthma and seasonal rhinitis, and proteases released by major allergenic pollens can injure airway epithelial cells in vitro. Disruption of mucosal epithelial integrity by proteases released by inhaled pollens could promote allergic sensitisation. Methods Pollen diffusates from Kentucky blue grass (Poa pratensis, rye grass (Lolium perenne and Bermuda grass (Cynodon dactylon were assessed for peptidase activity using a fluorogenic substrate, as well as by gelatin zymography. Following one- or two-dimensional gel electrophoresis, Coomassie-stained individual bands/spots were excised, subjected to tryptic digestion and analysed by mass spectrometry, either MALDI reflectron TOF or microcapillary liquid chromatography MS-MS. Database searches were used to identify allergens and other plant proteins in pollen diffusates. Results All pollen diffusates tested exhibited peptidase activity. Gelatin zymography revealed high Mr proteolytic activity at ~ 95,000 in all diffusates and additional proteolytic bands in rye and Bermuda grass diffusates, which appeared to be serine proteases on the basis of inhibition studies. A proteolytic band at Mr ~ 35,000 in Bermuda grass diffusate, which corresponded to an intense band detected by Western blotting using a monoclonal antibody to the timothy grass (Phleum pratense group 1 allergen Phl p 1, was identified by mass spectrometric analysis as the group 1 allergen Cyn d 1. Two-dimensional analysis similarly demonstrated proteolytic activity corresponding to protein spots identified as Cyn d 1. Conclusion One- and two-dimensional electrophoretic separation, combined with analysis by mass spectrometry, is useful for rapid determination of the identities of pollen proteins. A component of the proteolytic activity in Bermuda grass diffusate is likely to be related to the allergen Cyn d 1.

  20. Absorption spectrum of a V-type three-level atom driven by a coherent field

    International Nuclear Information System (INIS)

    Dong Po; Tang, S.H.

    2002-01-01

    We examine the absorption of a weak probe beam by a laser driven V-type atom with a pair of closely lying excited levels, where both the driving and probe lasers interact simultaneously with the two transitions. The effects of quantum interference among decay channels on the absorption spectra are also investigated. We introduce dipole moments in the dressed-state representation and the Hamiltonian in terms of the dressed states describing the interaction between the probe and the atom. In the degenerate case, features similar to that of a driven two-level atomic system are found due to some dark transitions in the spontaneous emission and the fact that the probe beam only detects certain transitions. In the nondegenerate case, the absorption spectrum is strongly influenced by the degree of quantum interference, resulting in different line shapes for emission peaks, absorption peaks, and dispersionlike profiles. The effect of probe polarization on the absorption spectrum is also investigated