New quasibound states of the compound nucleus in α -particle capture by the nucleus

Science.gov (United States)

Maydanyuk, Sergei P.; Zhang, Peng-Ming; Zou, Li-Ping

2017-07-01

We generalize the theory of nuclear decay and capture of Gamow that is based on tunneling through the barrier and internal oscillations inside the nucleus. In our formalism an additional factor is obtained, which describes distribution of the wave function of the the α particle inside the nuclear region. We discover new most stable states (called quasibound states) of the compound nucleus (CN) formed during the capture of α particle by the nucleus. With a simple example, we explain why these states cannot appear in traditional calculations of the α capture cross sections based on monotonic penetrabilities of a barrier, but they appear in a complete description of the evolution of the CN. Our result is obtained by a complete description of the CN evolution, which has the advantages of (1) a clear picture of the formation of the CN and its disintegration, (2) a detailed quantum description of the CN, (3) tests of the calculated amplitudes based on quantum mechanics (not realized in other approaches), and (4) high accuracy of calculations (not achieved in other approaches). These peculiarities are shown with the capture reaction of α +44Ca . We predict quasibound energy levels and determine fusion probabilities for this reaction. The difference between our approach and theory of quasistationary states with complex energies applied for the α capture is also discussed. We show (1) that theory does not provide calculations for the cross section of α capture (according to modern models of the α capture), in contrast with our formalism, and (2) these two approaches describe different states of the α capture (for the same α -nucleus potential).

Numerical simulation for the influence of laser-induced plasmas addition on air mass capture of hypersonic inlet

Science.gov (United States)

Zhao, Wei; Dou, Zhiguo; Li, Qian

2012-03-01

The theory of laser-induced plasmas addition to hypersonic airflow off a vehicle to increase air mass capture and improve the performance of hypersonic inlets at Mach numbers below the design value is explored. For hypersonic vehicles, when flying at mach numbers lower than the design one, we can increase the mass capture ratio of inlet through laser-induced plasmas injection to the hypersonic flow upstream of cowl lip to form a virtual cowl. Based on the theory, the model of interaction between laser-induced plasmas and hypersonic flow was established. The influence on the effect of increasing mass capture ratio was studied at different positions of laser-induced plasmas region for the external compression hypersonic inlet at Mach 5 while the design value is 6, the power of plasmas was in the range of 1-8mJ. The main results are as follows: 1. the best location of the plasma addition region is near the intersection of the nose shock of the vehicle with the continuation of the cowl line, and slightly below that line. In that case, the shock generated by the heating is close to the shock that is a reflection of the vehicle nose shock off the imaginary solid surface-extension of the cowl. 2. Plasma addition does increase mass capture, and the effect becomes stronger as more energy is added, the peak value appeared when the power of plasma was about 4mJ, when the plasma energy continues to get stronger, the mass capture will decline slowly.

Analysis of volatile compounds by open-air ionization mass spectrometry.

Science.gov (United States)

Meher, Anil Kumar; Chen, Yu-Chie

2017-05-08

This study demonstrates a simple method for rapid and in situ identification of volatile and endogenous compounds in culinary spice samples through mass spectrometry (MS). This method only requires a holder for solid spice sample (2-3 mm) that is placed close to a mass spectrometer inlet, which is applied with a high voltage. Volatile species responsible for the aroma of the spice samples can be readily detected by the mass spectrometer. Sample pretreatment is not required prior to MS analysis, and no solvent was used during MS analysis. The high voltage applied to the inlet of the mass spectrometer induces the ionization of volatile compounds released from the solid spice samples. Furthermore, moisture in the air also contributes to the ionization of volatile compounds. Dried spices including cinnamon and cloves are used as the model sample to demonstrate this straightforward MS analysis, which can be completed within few seconds. Furthermore, we also demonstrate the suitability of the current method for rapid screening of cinnamon quality through detection of the presence of a hepatotoxic agent, i.e. coumarin. Copyright © 2017 Elsevier B.V. All rights reserved.

HS-SPME optimization and extraction of volatile compounds from soursop (Annona muricata L. pulp with emphasis on their characteristic impact compounds

Directory of Open Access Journals (Sweden)

Karen Leticia de SANTANA

Full Text Available Abstract Aroma and taste are decisive factors in the selection of any food. The aim of this study was to extract the volatile compounds present in soursop (Annona muricata L. pulp by Solid-phase microextraction (SPME technique using 3 different fibers (DVB/CAR/ PDMS, CAR/PDMS and PDMS/DVB. An experimental design was set up to evaluate the best extraction conditions wherein the variables were adsorption temperature, ionic strength and pulp concentration. The separation of volatiles was performed in chromatographic columns of different polarity (polar and non-polar while volatile compounds were identified by analysis in high resolution gas chromatography system coupled with mass spectrometry. The results obtained using 3 different fibers revealed the capture of about 40 compounds. The CAR/PDMS fiber was more efficient for the capture of esters and DVB/CAR/PDMS fiber for terpenes. The optimum conditions for capture of higher number of volatiles for polar column were 45 °C for extraction, 15% of ionic strength and 50% of pulp concentration which resulted in separation of 87 compounds. Among the principal character impact compounds from soursop are (E-2-hexenoate, methyl hexenoate and linalool.

Analysis of organic compounds by secondary neutral mass spectrometry (SNMS) and secondary ion mass spectrometry (SIMS)

International Nuclear Information System (INIS)

Ewinger, H.P.

1993-05-01

This study is about the use of secondary neutral mass spectrometry (SNMS) and secondary ion mass spectrometry (SIMS) as analytical techniques with depth resolution in determining organic components in environmental solid microparticles. The first application of plasma SNMS to organic compounds revealed the spectra to be composed mainly of signals from the atoms of all participating elements, such as C, H, O, N, S, P, and Cl. In addition, signals produced by multi-atomic clusters can be detected, such as CH, C 2 , CH 2 , C 2 H, and C 3 , as well as signals indicating the presence of organic compounds with hetero elements, such as OH, NH, and CN. Their intensity decreases very markedly with increasing numbers of atoms. Among the signals from bi-atomic clusters, those coming from elements with large mass differences are most intense. The use of plasma SNMS with organic compounds has shown that, except for spurious chemical reactions induced by ion bombardment and photodesorption by the photons of the plasma, it is possible to analyze with resolution in depth, elements of organic solids. A more detailed molecular characterization of organic compounds is possible by means of SIMS on the basis of multi-atomic fragments and by comparison with suitable signal patterns. (orig./BBR) [de

Qualitative Analysis of E-Liquid Emissions as a Function of Flavor Additives Using Two Aerosol Capture Methods.

Science.gov (United States)

Eddingsaas, Nathan; Pagano, Todd; Cummings, Cody; Rahman, Irfan; Robinson, Risa; Hensel, Edward

2018-02-13

This work investigates emissions sampling methods employed for qualitative identification of compounds in e-liquids and their resultant aerosols to assess what capture methods may be sufficient to identify harmful and potentially harmful constituents present. Three popular e-liquid flavors (cinnamon, mango, vanilla) were analyzed using qualitative gas chromatography-mass spectrometry (GC-MS) in the un-puffed state. Each liquid was also machine-puffed under realistic-use flow rate conditions and emissions were captured using two techniques: filter pads and methanol impingers. GC-MS analysis was conducted on the emissions captured using both techniques from all three e-liquids. The e-liquid GC-MS analysis resulted in positive identification of 13 compounds from the cinnamon flavor e-liquid, 31 from mango, and 19 from vanilla, including a number of compounds observed in all e-liquid experiments. Nineteen compounds were observed in emissions which were not present in the un-puffed e-liquid. Qualitative GC-MS analysis of the emissions samples identify compounds observed in all three samples: e-liquid, impinge, and filter pads, and each subset thereof. A limited number of compounds were observed in emissions captured with impingers, but were not observed in emissions captured using filter pads; a larger number of compounds were observed on emissions collected from the filter pads, but not those captured with impingers. It is demonstrated that sampling methods have different sampling efficiencies and some compounds might be missed using only one method. It is recommended to investigate filter pads, impingers, thermal desorption tubes, and solvent extraction resins to establish robust sampling methods for emissions testing of e-cigarette emissions.

Determination of gaseous compounds using online mass spectrometry

International Nuclear Information System (INIS)

Praun, S.

1999-08-01

The work is divided in three major parts and describes various measurements of gaseous compounds. The first part tasks the problem of transit traffic along the motorway from Kufstein, Northern Tyrol/Austria until Ala, Trentino/Italy. During three periods measurements of the immissions of many compounds were carried out simultaneously in Northern Tyrol, Southern Tyrol and Trentino. The influence of the ban of heavy lorry traffic during the weekend and during the night on the reduction of NO 2 could be demonstrated. Furthermore certain compounds (e.g. Benzene) were monitored online for the first time along the motorway at lowest concentrations using the mass spectrometer 'Airsense 500'. In the second part online measurements of exhaled human breath after the oral application of a medicine against bronchitis was performed. In that way beside clinical and pharmacological studies the effectiveness of this pharmacon could be proved. The last part of the present work shows adsorption- and desorption measurements on four different adsorbents. During this procedure seven different gases with an increasing number of carbon atoms were monitored online by the hyphenation of these adsorbents with the mass spectrometer 'Airsense 500'. Thereby, the various properties of the adsorbents in the interaction with the gases could be demonstrated. (author)

Software in windows for staple compounding system of microcomputer nuclear mass scale

International Nuclear Information System (INIS)

Wang Yanting; Zhang Yongming; Wang Yu; Jin Dongping

1998-01-01

The software exploited in windows for staple compounding system of microcomputer nuclear mass scale is described. The staple compounding system is briefly narrated. The software structure and its realizing method are given

Determination of the Electron Neutrino Mass from Experiments on Electron-Capture Beta-Decay (EC)

CERN Multimedia

2002-01-01

The aim of the programme is to measure the electron-neutrino mass, for which at present an upper limit of 500~eV is known. \\\\ \\\\ The experiment studies the shape of the internal bremsstrahlung spectrum in electron-capture near its upper end-point and deduces a mass from small shape changes completely analogous to those in the well-known determination of the electron antineutrino mass in the tritium beta-minus decay. \\\\ \\\\ In a low-energy bremsstrahlung process, the capture takes place from a virtual S state associated with a radiative P~@A~S electromagnetic transition, and the resonant nature of the process leads to important enhancements of the photon intensities at low energy, in particular near the resonance energies co (X-rays). This effect gives this type of experiment a chance to compete with experiments on continuous beta spectra. \\\\ \\\\ The programme concentrates on two long-lived isotopes: \\\\ \\\\ 1)~~|1|6|3Ho. The Q value for this isotope has been found to be 2.6-2.7 keV. A detector specially construct...

Quantitative neutron capture radiography for studying the biodistribution of tumor-seeking boron-containing compounds

International Nuclear Information System (INIS)

Gabel, D.; Holstein, H.; Larsson, B.; Gille, L.; Ericson, G.; Sacker, D.; Som, P.; Fairchild, R.G.

1987-01-01

Biodistribution of two compounds presently considered for use in neutron capture therapy has been studied in mice carrying a transplantable Harding-Passey melanoma. A method is described by which quantitative assessment can be made of the boron distribution in whole-body sections of such animals. An alpha-particle-sensitive film is placed in close contact with a freeze-dried section of an animal and exposed to neutrons. The tracks visible after etching are analyzed optoelectronically in fields of 0.6 X 0.6 mm2 and compared to standards of boron homogeneously distributed in liver homogenates. The dynamic range of this method is about two orders of magnitude in concentration, with a lower detection limit of 0.1 to 0.01 ppm 10 B, depending on the rate of induction of spurious tracks by fast neutrons present in the neutron beam chosen. In a transplantable Harding-Passey melanoma in mice, it was found that the sulfhydryl boron hydride Na2B12H11SH presently used for therapy of glioblastoma clears blood, muscle, and brain very rapidly. Its accumulation in tumors was persistent for more than three days. A higher tumor accumulation was observed with its disulfide, which has been suggested for neutron capture therapy. For both compounds, a marked heterogeneity of boron distribution within one tumor was found

The capture of dark matter particles through the evolution of low-mass stars

International Nuclear Information System (INIS)

Lopes, Ilidio; Casanellas, Jordi; Eugenio, Daniel

2011-01-01

We studied the rate at which stars capture dark matter (DM) particles, considering different assumptions regarding the DM characteristics and, in particular, investigating how the stellar physics influences the capture rate. Two scenarios were considered: first, we assumed the maximal values for the spin-dependent and spin-independent DM particle-nucleon scattering cross sections allowed by the limits from direct detection experiments. Second, we considered that both scattering cross sections are of the same order, with the aim of studying the dependencies of the capture rate on stellar elements other than hydrogen. We found that the characteristics of the capture rate are very different in the two scenarios. Furthermore, we quantified the uncertainties on the computed capture rate (C χ ) and on the ratio between the luminosities from DM annihilations and thermonuclear reactions (L χ /L nuc ) derived from an imprecise knowledge of the stellar structure and DM parameters. For instance, while an uncertainty of 10% on the typical DM velocity leads to similar errors on the computed C χ and L χ /L nuc , the same uncertainty on the stellar mass becomes more relevant and duplicates the errors. Our results may be used to evaluate the reliability of the computed capture rate for the hypothetical use of stars other than the Sun as DM probes.

A critical assessment of boron target compounds for boron neutron capture therapy.

Science.gov (United States)

Hawthorne, M Frederick; Lee, Mark W

2003-01-01

Boron neutron capture therapy (BNCT) has undergone dramatic developments since its inception by Locher in 1936 and the development of nuclear energy during World War II. The ensuing Cold War spawned the entirely new field of polyhedral borane chemistry, rapid advances in nuclear reactor technology and a corresponding increase in the number to reactors potentially available for BNCT. This effort has been largely oriented toward the eradication of glioblastoma multiforme (GBM) and melanoma with reduced interest in other types of malignancies. The design and synthesis of boron-10 target compounds needed for BNCT was not channeled to those types of compounds specifically required for GBM or melanoma. Consequently, a number of potentially useful boron agents are known which have not been biologically evaluated beyond a cursory examination and only three boron-10 enriched target species are approved for human use following their Investigational New Drug classification by the US Food and Drug Administration; BSH, BPA and GB-10. All ongoing clinical trials with GBM and melanoma are necessarily conducted with one of these three species and most often with BPA. The further development of BNCT is presently stalled by the absence of strong support for advanced compound evaluation and compound discovery driven by recent advances in biology and chemistry. A rigorous demonstration of BNCT efficacy surpassing that of currently available protocols has yet to be achieved. This article discusses the past history of compound development, contemporary problems such as compound classification and those problems which impede future advances. The latter include means for biological evaluation of new (and existing) boron target candidates at all stages of their development and the large-scale synthesis of boron target species for clinical trials and beyond. The future of BNCT is bright if latitude is given to the choice of clinical disease to be treated and if a recognized study

Accounting for undetected compounds in statistical analyses of mass spectrometry 'omic studies.

Science.gov (United States)

Taylor, Sandra L; Leiserowitz, Gary S; Kim, Kyoungmi

2013-12-01

Mass spectrometry is an important high-throughput technique for profiling small molecular compounds in biological samples and is widely used to identify potential diagnostic and prognostic compounds associated with disease. Commonly, this data generated by mass spectrometry has many missing values resulting when a compound is absent from a sample or is present but at a concentration below the detection limit. Several strategies are available for statistically analyzing data with missing values. The accelerated failure time (AFT) model assumes all missing values result from censoring below a detection limit. Under a mixture model, missing values can result from a combination of censoring and the absence of a compound. We compare power and estimation of a mixture model to an AFT model. Based on simulated data, we found the AFT model to have greater power to detect differences in means and point mass proportions between groups. However, the AFT model yielded biased estimates with the bias increasing as the proportion of observations in the point mass increased while estimates were unbiased with the mixture model except if all missing observations came from censoring. These findings suggest using the AFT model for hypothesis testing and mixture model for estimation. We demonstrated this approach through application to glycomics data of serum samples from women with ovarian cancer and matched controls.

Determination of nitrosourea compounds in brain tissue by gas chromatography and electron capture detection.

Science.gov (United States)

Hassenbusch, S J; Colvin, O M; Anderson, J H

1995-07-01

A relatively simple, high-sensitivity gas chromatographic assay is described for nitrosourea compounds, such as BCNU [1,3-bis(2-chloroethyl)-1-nitrosourea] and MeCCNU [1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea], in small biopsy samples of brain and other tissues. After extraction with ethyl acetate, secondary amines in BCNU and MeCCNU are derivatized with trifluoroacetic anhydride. Compounds are separated and quantitated by gas chromatography using a capillary column with temperature programming and an electron capture detector. Standard curves of BCNU indicate a coefficient of variance of 0.066 +/- 0.018, a correlation coefficient of 0.929, and an extraction efficiency from whole brain of 68% with a minimum detectable amount of 20 ng in 5-10 mg samples. The assay has been facile and sensitive in over 1000 brain biopsy specimens after intravenous and intraarterial infusions of BCNU.

Mass spectra of alicylic compounds Pt. 8

International Nuclear Information System (INIS)

Remane, H.; Haufe, G.

1980-01-01

Mass spectrometric fragmentation of C 5 -C 8 as well as C 12 ring systems of tBHC and tBMC is discussed and compared to the fragmentation of Br-, hydroxy- and methoxy cycloalkanes of similar ring sizes. The dominant processes are the splitting of the functional groups yielding M-H 2 O 1+ , M-HOCH 3 1+ and M-Br 1+ fragments, and the disintegration of the rings producing C 3 H 4 X 1+ fragments (X=Br, OH, OCH 3 ). Intensities of the more important fragments correspond to the size of the ring. The isomers can be distinguished by their mass spectra due to the inequality of the intensities of the trans- and cis-forms of BHC and BMC. Functional groups influence mass spectrometric fragmentation as it is indicated by the correlation of the fragments of the bis-functional tBHC and tBMC and the fragments of monofractional compounds. (Sz.J.)

Plasma osmolyte concentrations and rectal gland mass of bull sharks Carcharhinus leucas, captured along a salinity gradient.

Science.gov (United States)

Pillans, Richard D; Franklin, Craig E

2004-07-01

Bull sharks (Carcharhinus leucas) were captured across a salinity gradient from freshwater (FW) to seawater (SW). Across all salinities, C. leucas were hyperosmotic to the environment. Plasma osmolarity in FW-captured animals (642 +/- 7 mosM) was significantly reduced compared to SW-captured animals (1067 +/- 21 mosM). In FW animals, sodium, chloride and urea were 208 +/- 3, 203 +/- 3 and 192 +/- 2 mmol l(-1), respectively. Plasma sodium, chloride and urea in SW-captured C. leucas were 289 +/- 3, 296 +/- 6 and 370 +/- 10 mmol l(-1), respectively. The increase in plasma osmolarity between FW and SW was not linear. Between FW (3 mosM) and 24 per thousand SW (676 mosM), plasma osmolarity increased by 22% or 0.92% per 1 per thousand rise in salinity. Between 24 per thousand and 33 per thousand, plasma osmolarity increased by 33% or 4.7% per 1 per thousand rise in salinity, largely due to a sharp increase in plasma urea between 28 per thousand and 33 per thousand. C. leucas moving between FW and SW appear to be faced with three major osmoregulatory challenges, these occur between 0-10 per thousand, 11-20 per thousand and 21-33 per thousand. A comparison between C. leucas captured in FW and estuarine environments (20-28 per thousand ) in the Brisbane River revealed no difference in the mass of rectal glands between these animals. However, a comparison of rectal gland mass between FW animals captured in the Brisbane River and Rio San Juan/Lake Nicaragua showed that animals in the latter system had a significantly smaller rectal gland mass at a given length than animals in the Brisbane River. The physiological challenges and mechanisms required for C. leucas moving between FW and SW, as well as the ecological implications of these data are discussed.

Chemical processes in neutron capture therapy

International Nuclear Information System (INIS)

Brown, B.J.

1975-01-01

Research into the radiation chemical effects of neutron capture therapy are described. In the use of neutron capture therapy for the treatment of brain tumours, compounds containing an activatable nuclide are selectively concentrated within tumour tissue and irradiated with neutrons. Target compounds for use in therapy must accumulate selectively in high concentrations in the tumour and must be non toxic to the patient. The most suitable of these are the boron hydrides. Radiation dosages, resulting from neutron capture in normal tissue constituents are tabulated. As part of the program to study the radiation-induced chemical processes undergone by boron target compounds, the radiolytic degredation of boron hydride and phenyl boric acid system was investigated. No direct dependence between the yield of the transient radiolytic species and the concentration of the B-compound was observed. (author)

Strategies for dereplication of natural compounds using high-resolution tandem mass spectrometry.

Science.gov (United States)

Kind, Tobias; Fiehn, Oliver

2017-09-01

Complete structural elucidation of natural products is commonly performed by nuclear magnetic resonance spectroscopy (NMR), but annotating compounds to most likely structures using high-resolution tandem mass spectrometry is a faster and feasible first step. The CASMI contest 2016 (Critical Assessment of Small Molecule Identification) provided spectra of eighteen compounds for the best manual structure identification in the natural products category. High resolution precursor and tandem mass spectra (MS/MS) were available to characterize the compounds. We used the Seven Golden Rules, Sirius2 and MS-FINDER software for determination of molecular formulas, and then we queried the formulas in different natural product databases including DNP, UNPD, ChemSpider and REAXYS to obtain molecular structures. We used different in-silico fragmentation tools including CFM-ID, CSI:FingerID and MS-FINDER to rank these compounds. Additional neutral losses and product ion peaks were manually investigated. This manual and time consuming approach allowed for the correct dereplication of thirteen of the eighteen natural products.

Precision electron-capture energy in {sup 202}Pb and its relevance for neutrino mass determination

Energy Technology Data Exchange (ETDEWEB)

Welker, A. [CERN, Geneva (Switzerland); Technische Universitaet Dresden, Dresden (Germany); Filianin, P. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Althubiti, N.A.S. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); Atanasov, D.; Blaum, K.; Eliseev, S.; Kreim, S. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Cocolios, T.E. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Herfurth, F.; Neidherr, D. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Lunney, D. [CSNSM-IN2P3-CNRS, Universite Paris-Sud, Orsay (France); Manea, V. [CERN, Geneva (Switzerland); Novikov, Yu. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Physics Faculty, St. Petersburg State University (Russian Federation); Rosenbusch, M.; Schweikhard, L.; Wienholtz, F. [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, Greifswald (Germany); Wolf, R.N. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); The University of Sydney, ARC Centre of Excellence for Engineered Quantum Systems, Sydney (Australia); Zuber, K. [Technische Universitaet Dresden, Dresden (Germany)

2017-07-15

Within the framework of an extensive programme devoted to the search for alternative candidates for the neutrino mass determination, the atomic mass difference between {sup 202}Pb and {sup 202}Tl has been measured with the Penning trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN. The obtained value Q{sub EC} = 38.8(43) keV is three times more precise than the AME2012 value. While it will probably not lead to a replacement of {sup 163}Ho in modern experiments on the determination of the electron-neutrino mass, the electron capture in {sup 202}Pb would however allow a determination of the electron-neutrino mass on the few-eV level using a cryogenic micro-calorimeter. (orig.)

High-Throughput and Rapid Screening of Low-Mass Hazardous Compounds in Complex Samples.

Science.gov (United States)

Wang, Jing; Liu, Qian; Gao, Yan; Wang, Yawei; Guo, Liangqia; Jiang, Guibin

2015-07-07

Rapid screening and identification of hazardous chemicals in complex samples is of extreme importance for public safety and environmental health studies. In this work, we report a new method for high-throughput, sensitive, and rapid screening of low-mass hazardous compounds in complex media without complicated sample preparation procedures. This method is achieved based on size-selective enrichment on ordered mesoporous carbon followed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry analysis with graphene as a matrix. The ordered mesoporous carbon CMK-8 can exclude interferences from large molecules in complex samples (e.g., human serum, urine, and environmental water samples) and efficiently enrich a wide variety of low-mass hazardous compounds. The method can work at very low concentrations down to part per trillion (ppt) levels, and it is much faster and more facile than conventional methods. It was successfully applied to rapidly screen and identify unknown toxic substances such as perfluorochemicals in human serum samples from athletes and workers. Therefore, this method not only can sensitively detect target compounds but also can identify unknown hazardous compounds in complex media.

Mass measurements of neutron rich isotopes in the Fe region and electron capture processes in neutron star crusts

International Nuclear Information System (INIS)

Estrade, Alfredo; Matos, M.; Schatz, Hendrik; Amthor, A.M.; Beard, Mary; Brown, Edward; Bazin, D.; Becerril, A.; Elliot, T.; Gade, A.; Galaviz, D.; Gupta, Sanjib; Hix, William Raphael; Lau, Rita; Moeller, Peter; Pereira, J.; Portillo, M.; Rogers, A.M.; Shapira, Dan; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, Michael

2011-01-01

Experimental knowledge of nuclear masses of exotic nuclei is important for understanding nuclear structure far from the valley of stability, and as a direct input into astrophysical models. Electron capture processes in the crust of accreting neutron stars have been proposed as a heat source that can affect the thermal structure of the star. Nuclear masses of very neutron-rich nuclides are necessary inputs to model the electron capture process. The time-of-flight (TOF) mass measurement technique allows measurements on very short-lived nuclei. It has been effectively applied using the fast fragment beams produced at the National Superconducting Cyclotron Lab (NSCL) to reach masses very far from stability. Measurements were performed for neutron-rich isotopes in the region of the N=32 and N=40 subshells, which coincides with the mass range of carbon superburst ashes. We discuss reaction network calculations performed to investigate the impact of our new measurements and to compare the effect of using different global mass models in the calculations. It is observed that the process is sensitive to the differences in the odd-even mass staggering predicted by the mass models, and our new result for 66Mn has a significant impact on the distribution of heat sources in the crust.

Low Mass Printable Devices for Energy Capture, Storage, and Use

Science.gov (United States)

Frazier, Donald O.; Singer, Christopher E.; Rogers, Jan R.; Schramm, Harry F.; Fabisinski, Leo L.; Lowenthal, Mark; Ray, William J.; Fuller, Kirk A.

2010-01-01

The energy-efficient, environmentally friendly technology that will be presented is the result of a Space Act Agreement between NthDegree Technologies Worldwide, Inc., and the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC). The work combines semiconductor and printing technologies to advance lightweight electronic and photonic devices having excellent potential for commercial and exploration applications. Device development involves three projects that relate to energy generation and consumption: (1) a low-mass efficient (low power, low heat emission) micro light-emitting diode (LED) area lighting device; (2) a low-mass omni-directional efficient photovoltaic (PV) device with significantly improved energy capture; and (3) a new approach to building super-capacitors. These three technologies, energy capture, storage, and usage (e.g., lighting), represent a systematic approach for building efficient local micro-grids that are commercially feasible; furthermore, these same technologies, appropriately replacing lighting with lightweight power generation, will be useful for enabling inner planetary missions using smaller launch vehicles and to facilitate surface operations during lunar and planetary surface missions. The PV device model is a two sphere, light trapped sheet approximately 2-mm thick. The model suggests a significant improvement over current thin film systems. For lighting applications, all three technology components are printable in-line by printing sequential layers on a standard screen or flexographic direct impact press using the three-dimensional printing technique (3DFM) patented by NthDegree. One primary contribution to this work in the near term by the MSFC is to test the robustness of prototype devices in the harsh environments that prevail in space and on the lunar surface. It is anticipated that this composite device, of which the lighting component has passed off-gassing testing, will function

Performance Evaluation of the Scent Transfer Unit (STU) for Organic Compound Collection and Release

Energy Technology Data Exchange (ETDEWEB)

Eckenrode, Brian A. [Federal Bureau of Investigation; Ramsey, Scott A. [Federal Bureau of Investigation; StockhamMFS, Rex A. [Federal Bureau of Investigation; Van Berkel, Gary J [ORNL; Asano, Keiji G [ORNL; Wolf, Dennis A [ORNL

2006-01-01

The Scent Transfer UnitTM (STU-100) is a portable vacuum that uses airflow through a sterile gauze pad to capture a volatiles profile over evidentiary items for subsequent canine presentation to assist law enforcement personnel. This device was evaluated to determine its ability to trap and release organic compounds at ambient temperature under controlled laboratory conditions. Gas chromatography-mass spectrometry (GC-MS) analyses using a five-component volatiles mixture in methanol injected directly into a capture pad indicated that compound release could be detected initially and three days after time of collection. Additionally, fifteen compounds of a 39-component toxic organics gaseous mixture (10-1,000 ppbv) were trapped, released, and detected in the headspace of a volatiles capture pad after being exposed to this mixture using the STU-100 with analysis via GC-MS. Component release efficiencies at ambient temperature varied with the analyte; however, typical values of approximately 10 percent were obtained. Desorption at elevated temperatures of reported human odor/scent chemicals and colognes trapped by the STU-100 pads was measured and indicated that the STU-100 has a significant trapping efficiency at ambient temperature. Multivariate statistical analysis of subsequent mass spectral patterns was also performed.

Performance evaluation of the Scent Transfer Unit (STU-100) for organic compound collection and release.

Science.gov (United States)

Eckenrode, Brian A; Ramsey, Scott A; Stockham, Rex A; Van Berkel, Gary J; Asano, Keiji G; Wolf, Dennis A

2006-07-01

The Scent Transfer Unit (STU-100) is a portable vacuum that uses airflow through a sterile gauze pad to capture a volatiles profile over evidentiary items for subsequent canine presentation to assist law enforcement personnel. This device was evaluated to determine its ability to trap and release organic compounds at ambient temperature under controlled laboratory conditions. Gas chromatography-mass spectrometry (GC-MS) analyses using a five-component volatiles mixture in methanol injected directly into a capture pad indicated that compound release could be detected initially and 3 days after the time of collection. Additionally, 15 compounds of a 39-component toxic organic gaseous mixture (10-1000 parts per billion by volume [p.p.b.(v)]) were trapped, released, and detected in the headspace of a volatiles capture pad after being exposed to this mixture using the STU-100 with analysis via GC-MS. Component release efficiencies at ambient temperature varied with the analyte; however, typical values of c. 10% were obtained. Desorption at elevated temperatures of reported human odor/scent chemicals and colognes trapped by the STU-100 pads was measured and indicated that the STU-100 has a significant trapping efficiency at ambient temperature. Multivariate statistical analysis of subsequent mass spectral patterns was also performed.

Characterization of Volatile Compounds from Ethnic Agave Alcoholic Beverages by Gas Chromatography-Mass Spectrometry

Directory of Open Access Journals (Sweden)

Pilar Escalante-Minakata

2008-01-01

Full Text Available Ethnic Agave alcoholic beverages such as raicilla, sisal, tequila, mezcal, bacanora, sotol and pulque have been analyzed by gas chromatography and headspace solid-phase microextraction- gas chromatography-mass spectrometry (HS-SPME-GC-MS. There were 105 compounds identified, eleven were classified as major compounds and the others were classified as minor compounds. Seventeen minor compounds could be used as authenticity markers since they were beverage specific. Cluster analysis (CA showed that Agave alcoholic beverages could be distinguished by multivariate analysis of major compounds; however, the analysis of minor compounds provided a better fingerprinting.

Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionization mass spectrometry.

NARCIS (Netherlands)

Rusina, T.; Korytar, P.; de Boer, J.

2011-01-01

Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group

Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionisation mass spectrometry

NARCIS (Netherlands)

Rusina, T.; Korytar, P.; Boer, de J.

2011-01-01

Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group

PbSnTe:In compound: Electron capture levels, galvanomagnetic properties, and THz sensitivity

Energy Technology Data Exchange (ETDEWEB)

Ishchenko, D. V., E-mail: miracle4348@gmail.com; Klimov, A. E.; Shumsky, V. N.; Epov, V. S. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

2016-12-15

A model of the Pb{sub 1–x}Sn{sub x}Te:In compound, based on concepts of the theory of disordered systems is considered. The temperature dependences of the Fermi-level position and carrier concentration are calculated depending on the indium doping level and are compared with experimental data. The transient current–voltage characteristics are calculated in the mode of injection from the contact and current limitation by space charge at various voltage-variation rates. The data obtained are compared with the experiments. It is demonstrated that the shape of the characteristics is controlled by the parameters of electron capture at localized states. Photocurrent relaxation in a magnetic field is studied, and the mechanism of such relaxation is discussed under the assumption of the magnetic freezing of carriers.

Storage ion trap of an 'In-Flight Capture' type for precise mass measurement of radioactive nuclear reaction products and fission fragments

International Nuclear Information System (INIS)

Tarantin, N.I.

2001-01-01

Data on nuclear masses provide a basis for creating and testing various nuclear models. A tandem system of FLNR comprised of the U-400M cyclotron, the COMBAS magnetic separator and the mass-spectrometric ion trap of an 'in-flight capture' type is considered as a possible complex for producing of the short-lived nuclei in fragmentation reactions by heavy ions and for precise mass measurement of these nuclei. The plan of scientific and technical FLNR research includes a project DRIBs for producing beams of accelerated radioactive nuclear reaction products and photofission fragments. This project proposes also precise mass measurements of the fission fragment with the help of the ion trap. The in-flight entrance of the ions and their capture in the mass-spectrometric ion trap using the monochromatizing degrader, the static electric and magnetic fields and a new invention, a magnetic unidirectional transporting ventil, is considered

Effect of a new matrix system for low-polar organic compounds in fast atom bombardment mass spectrometry

International Nuclear Information System (INIS)

Takayama, Mitsuo; Fukai, Toshio; Nomura, Taro

1988-01-01

A new matrix system m-NBA-DTDE (1:1) for FABMS of low-polar compounds, such as cholesterol and stearic acid methyl ester, was prepared. The system, i.e., a 1:1 mixture of m-NBA (m-nitrobenzyl alcohol) to DTDE (2,2-dithiodiethanol or 2-hydroxyethyl disulfide), contributed to measuring the positive ion FAB mass spectra of above compounds and morusin permethyl ether, and it brought an effective result on the ion current lifetime and the reproducibility of their spectra. The positive ion FAB mass spectra of these low-polar compounds were compared with the corresponding positive ion EI and CI mass spectra. (author)

Astrophysical neutron capture rates in s- and r-process nucleosynthesis

International Nuclear Information System (INIS)

Beer, H.; Mohr, P.; Oberhummer, H.; Rauscher, T.; Mutti, P.; Corvi, F.; Sedyshev, P.V.; Popov, Yu.P.

1997-01-01

The astrophysical neutron capture rates of light and heavy nuclei are measured and calculated. The measurements are realized using the activation technique at the 3.75 MV Karlsruhe Van de Graaff accelerator and by means of the time-of-flight method at the Geel electron linear accelerator (GELINA). The setup for the fast cyclic activation measurements made on 26 Mg and 48 Ca, as well as on Pt isotopes is described. The time-of-flight method is used for neutron capture measurements of the bottleneck isotopes 138 Ba and 208 Pb. The calculations are made using direct and compound nuclear capture models. The s-process nucleosynthesis path in the Os and Pt mass region is discussed in details. It is shown that for 19 '1 Os, 192 Ir and 193 Pt there is a competition between β-decay and neutron capture. The β-decay half-lives are dependent on temperature and electron density of the s-process environment. The abundance of s-only 192 Pt originates from the branching at 191 Os and 192 Ir. The isotopes 190 Pt and 198 Pt are not on the s-process path, therefore the seed abundance vanish during nucleosynthesis. Calculations are carried out using parametrized models in order to reproduce the s-process abundance in the mass region from Os up to Pt. The neutron density is adjusted to reproduce the solar abundance of the s-only isotope 9 2 Pt in the analysis of the present branching especially

Mass attenuation coefficient of chromium and manganese compounds around absorption edge.

Science.gov (United States)

Sharanabasappa; Kaginelli, S B; Kerur, B R; Anilkumar, S; Hanumaiah, B

2009-01-01

The total mass attenuation coefficient for Potassium dichromate, Potassium chromate and Manganese acetate compounds are measured at different photon energies 5.895, 6.404, 6.490, 7.058, 8.041 and 14.390 keV using Fe-55, Co-57 and 241Am source with Copper target, radioactive sources. The photon intensity is analyzed using a high resolution HPGe detector system coupled to MCA under good geometrical arrangement. The obtained values of mass attenuation coefficient values are compared with theoretical values. This study suggests that measured mass attenuation coefficient values at and near absorption edges differ from the theoretical value by about 5-28%.

Meson exchange second class currents and the neutrino mass in the muon capture by light nuclei

International Nuclear Information System (INIS)

Katkhat, Ch.L.

1988-01-01

Influence of the Kubodera-Delorme-Rho model parameters (ζ and ξ), the scalar form factor (F s ) and the muonic neutrino rest mass (m νμ ) on the asymmetry coefficient (α μν ) of neutrino emission with respect to the muon spin orientation in the muon capture by light nuclei is analyzed. It is shown, that the mass m νμ , the parameters of ζ and ξ, and the form factor F s may be estimated by studying the coefficient α μν in O -> O, Gamov-Teller, and mixed transitions, respectively

Precision mass measurements for studies of nucleosynthesis via the rapid neutron-capture process. Penning-trap mass measurements of neutron-rich cadmium and caesium isotopes

Energy Technology Data Exchange (ETDEWEB)

Atanasov, Dinko

2016-07-06

Although the theory for the rapid neutron-capture process (r-process) was developed more than 55 years ago, the astrophysical site is still under a debate. Theoretical studies predict that the r-process path proceeds through very neutron-rich nuclei with very asymmetric proton-to-neutron ratios. Knowledge about the properties of neutron-rich isotopes found in similar regions of the nuclear chart and furthermore suitable for r-process studies is still little or even not existing. The basic nuclear properties such as binding energies, half-lives, neutron-induced or neutron-capture reaction cross-sections, play an important role in theoretical simulations and can vary or even drastically alternate results of these studies. Therefore, a considerable effort was put forward to access neutron-rich isotopes at radioactive ion-beam facilities like ISOLDE at CERN. The goal of this PhD thesis is to describe the experimental work done for the precision mass measurements of neutron-rich cadmium ({sup 129-131}Cd) and caesium ({sup 132,146-148}Cs) isotopes. Measurements were done at the on-line radioactive ion-beam facility ISOLDE by using the four-trap mass spectrometer ISOLTRAP. The cadmium isotopes are key nuclides for the synthesis of stable isotopes around the mass peak A = 130 in the Solar System abundance.

A qualitative study of amlodipine and its related compounds by electrospray ionization tandem mass spectrometry.

Science.gov (United States)

Gibbons, John; Pugh, Jonathan; Dimopoulos-Italiano, Gina; Pike, Richard

2006-01-01

A comprehensive structural analysis of amlodipine and certain related compounds was performed by electrospray ionization tandem mass spectrometry. Triple quadrupole and quadrupole time-of-flight instruments were used to provide collision-induced dissociation and accurate mass measurement for selected product and second-generation product ions. A unique ion rearrangement was observed, which was found to be characteristic of certain dihydropyridines. This study provides a fundamental understanding of the fragmentation of these compounds. The structural elucidation of an unknown impurity is presented as an example. Copyright (c) 2006 John Wiley & Sons, Ltd.

Mathematical Modeling of a Transient Vibration Control Strategy Using a Switchable Mass Stiffness Compound System

Directory of Open Access Journals (Sweden)

Diego Francisco Ledezma-Ramirez

2014-01-01

Full Text Available A theoretical control strategy for residual vibration control resulting from a shock pulse is studied. The semiactive control strategy is applied in a piecewise linear compound model and involves an on-off logic to connect and disconnect a secondary mass stiffness system from the primary isolation device, with the aim of providing high energy dissipation for lightly damped systems. The compound model is characterized by an energy dissipation mechanism due to the inelastic collision between the two masses and then viscous damping is introduced and its effects are analyzed. The objective of the simulations is to evaluate the transient vibration response in comparison to the results for a passive viscously damped single degree-of-freedom system considered as the benchmark or reference case. Similarly the decay in the compound system is associated with an equivalent decay rate or logarithmic decrement for direct comparison. It is found how the compound system provides improved isolation compared to the passive system, and the damping mechanisms are explained.

Fully Automated Laser Ablation Liquid Capture Sample Analysis using NanoElectrospray Ionization Mass Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Lorenz, Matthias [ORNL; Ovchinnikova, Olga S [ORNL; Van Berkel, Gary J [ORNL

2014-01-01

RATIONALE: Laser ablation provides for the possibility of sampling a large variety of surfaces with high spatial resolution. This type of sampling when employed in conjunction with liquid capture followed by nanoelectrospray ionization provides the opportunity for sensitive and prolonged interrogation of samples by mass spectrometry as well as the ability to analyze surfaces not amenable to direct liquid extraction. METHODS: A fully automated, reflection geometry, laser ablation liquid capture spot sampling system was achieved by incorporating appropriate laser fiber optics and a focusing lens into a commercially available, liquid extraction surface analysis (LESA ) ready Advion TriVersa NanoMate system. RESULTS: Under optimized conditions about 10% of laser ablated material could be captured in a droplet positioned vertically over the ablation region using the NanoMate robot controlled pipette. The sampling spot size area with this laser ablation liquid capture surface analysis (LA/LCSA) mode of operation (typically about 120 m x 160 m) was approximately 50 times smaller than that achievable by direct liquid extraction using LESA (ca. 1 mm diameter liquid extraction spot). The set-up was successfully applied for the analysis of ink on glass and paper as well as the endogenous components in Alstroemeria Yellow King flower petals. In a second mode of operation with a comparable sampling spot size, termed laser ablation/LESA , the laser system was used to drill through, penetrate, or otherwise expose material beneath a solvent resistant surface. Once drilled, LESA was effective in sampling soluble material exposed at that location on the surface. CONCLUSIONS: Incorporating the capability for different laser ablation liquid capture spot sampling modes of operation into a LESA ready Advion TriVersa NanoMate enhanced the spot sampling spatial resolution of this device and broadened the surface types amenable to analysis to include absorbent and solvent resistant

Determination of isotope ratio of elements by mass distribution in molecules of varied chemical compounds

International Nuclear Information System (INIS)

Gladkikh, I.S.; Babichev, A.P.

1999-01-01

The procedure and program for calculation of isotope ratio of elements involving in the compound being studied using data of mass spectrometry were elaborated. The methods developed for the O 2 , SiH 4 , Cd(CH 3 ) 2 molecules were demonstrated for the illustration. The results of calculation provide support for the efficiency of the program and satisfactory reliability of the results during calculation of the isotope and complex compound concentrations. The program may be used for the estimation of the degree of nonequilibrium isotope distributions, it may indicate on the errors of the mass spectroscopy results [ru

Long-term captures of low-mass intruders by binary stars

International Nuclear Information System (INIS)

Hills, J.G.

1983-01-01

Intensive computer simulations were made of three families of encounters between a binary star and a low-mass intruder which previous work indicated have a high probability of producing long-lived triple-star systems. For comparison, a fourth family which produces few long-lived trinaries was also studied. In the first two families, the binary components are equally massive and the closest approach of the intruder to the center of mass of the binary is about two times its semimajor axis, a 0 . In Family 1, the orbit of the original binary is circular, e = 0, while in Family 2, e 0 = 0.95. In Family 3 one binary component is 100 times as massive as the other, the orbit is circular, and the low-mass intruder enters the binary at nearly zero impact parameter. The probability that the intruder is trapped for at least one revolution around the binary is 0.24, 0.46, and 0.51, respectively, for these three families of encounters. The fraction of the intruders surviving successive revolutions drops rapidly. However, one encounter in Family 1 and two in Family 3 resulted in the intruder making more than 300 revolutions around the inner binary before escaping. Some intruders remained bound for more than 20 000 revolutions of the inner binary. The longest duration captures occur when the intruder is thrown into an orbit with a very large semimajor axis. About 20% of the encounters in the three families result in the intruder being thrown into an orbit with a semimajor axis a>100 a 0 , while about 2% result in the intruder going into an orbit with a>1000 a 0 . Intruders thrown into these large semimajor axis orbits have the best chance of having their orbits stabilized by passing stars

Thermogravimetric-mass spectrometric study on the evolution of nitrogen compounds during coal devolatilisation

Energy Technology Data Exchange (ETDEWEB)

Arenillas, A.; Rubiera, F.; Pevida, C.; Pis, J.J. [Department of Energy and Environment, Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain)

2002-10-01

Emissions of nitrogen oxides during coal combustion are a major environmental problem. The chemically bound nitrogen in fuel accounts for up to 80% of total NO{sub x} emissions. In this respect, fundamental studies are needed to clarify the mechanisms and to identify the different species that are precursors in the formation of the NO{sub x}. Mass spectrometry (MS) has been used for decades as a successful technique in evolved gas analysis. However, MS is normally used to identify typical volatile compounds formed during coal pyrolysis (i.e. H{sub 2}, CH{sub 4}, CO, CO{sub 2} and H{sub 2}O) but very few works on the detection by MS of nitrogen compounds during coal devolatilisation can be found. In this work, the possibility of detecting different nitrogen compounds by means of thermogravimetric-MS during the temperature-programmed pyrolysis of coal was evaluated. Interferences in the N-compounds MS signals were determined. The use of model compounds provided additional information on the MS response factors of the volatile compounds produced.

CAPTURE OF TROJANS BY JUMPING JUPITER

International Nuclear Information System (INIS)

Nesvorný, David; Vokrouhlický, David; Morbidelli, Alessandro

2013-01-01

Jupiter Trojans are thought to be survivors of a much larger population of planetesimals that existed in the planetary region when planets formed. They can provide important constraints on the mass and properties of the planetesimal disk, and its dispersal during planet migration. Here, we tested a possibility that the Trojans were captured during the early dynamical instability among the outer planets (aka the Nice model), when the semimajor axis of Jupiter was changing as a result of scattering encounters with an ice giant. The capture occurs in this model when Jupiter's orbit and its Lagrange points become radially displaced in a scattering event and fall into a region populated by planetesimals (that previously evolved from their natal transplanetary disk to ∼5 AU during the instability). Our numerical simulations of the new capture model, hereafter jump capture, satisfactorily reproduce the orbital distribution of the Trojans and their total mass. The jump capture is potentially capable of explaining the observed asymmetry in the number of leading and trailing Trojans. We find that the capture probability is (6-8) × 10 –7 for each particle in the original transplanetary disk, implying that the disk contained (3-4) × 10 7 planetesimals with absolute magnitude H disk ∼ 14-28 M Earth , is consistent with the mass deduced from recent dynamical simulations of the planetary instability.

EVOLUTION OF PROGENITORS FOR ELECTRON CAPTURE SUPERNOVAE

International Nuclear Information System (INIS)

Takahashi, Koh; Umeda, Hideyuki; Yoshida, Takashi

2013-01-01

We provide progenitor models for electron capture supernovae (ECSNe) with detailed evolutionary calculation. We include minor electron capture nuclei using a large nuclear reaction network with updated reaction rates. For electron capture, the Coulomb correction of rates is treated and the contribution from neutron-rich isotopes is taken into account in each nuclear statistical equilibrium (NSE) composition. We calculate the evolution of the most massive super asymptotic giant branch stars and show that these stars undergo off-center carbon burning and form ONe cores at the center. These cores become heavier up to the critical mass of 1.367 M ☉ and keep contracting even after the initiation of O+Ne deflagration. Inclusion of minor electron capture nuclei causes convective URCA cooling during the contraction phase, but the effect on the progenitor evolution is small. On the other hand, electron capture by neutron-rich isotopes in the NSE region has a more significant effect. We discuss the uniqueness of the critical core mass for ECSNe and the effect of wind mass loss on the plausibility of our models for ECSN progenitors.

Study on aroma components of osmanthus by absorption wire gas chromatography/mass spectrometry

International Nuclear Information System (INIS)

Feng Janyue; Zhao Jing; Huang Qiaoqiao; Feng Lianmei

2001-01-01

The aroma components of fresh osmanthus are captured by absorption wires. The fragrant components absorbed in the wires are desorbed immediately at 358 degree C in Curie-point pyrolyzed, and then led into GC/MS to analyze. As a result, 41 aroma compounds such as β-linalool, linalooloxide, β-ocimene etc. in osmanthus are detected qualitatively by gas chromatography/mass spectrometry. This method can be used to analyze the change of aroma compounds of fresh flowers while blossoming

Air and Surface Sampling Method for Assessing Exposures to Quaternary Ammonium Compounds Using Liquid Chromatography Tandem Mass Spectrometry.

Science.gov (United States)

LeBouf, Ryan F; Virji, Mohammed Abbas; Ranpara, Anand; Stefaniak, Aleksandr B

2017-07-01

This method was designed for sampling select quaternary ammonium (quat) compounds in air or on surfaces followed by analysis using ultraperformance liquid chromatography tandem mass spectrometry. Target quats were benzethonium chloride, didecyldimethylammonium bromide, benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. For air sampling, polytetrafluoroethylene (PTFE) filters are recommended for 15-min to 24-hour sampling. For surface sampling, Pro-wipe® 880 (PW) media was chosen. Samples were extracted in 60:40 acetonitrile:0.1% formic acid for 1 hour on an orbital shaker. Method detection limits range from 0.3 to 2 ng/ml depending on media and analyte. Matrix effects of media are minimized through the use of multiple reaction monitoring versus selected ion recording. Upper confidence limits on accuracy meet the National Institute for Occupational Safety and Health 25% criterion for PTFE and PW media for all analytes. Using PTFE and PW analyzed with multiple reaction monitoring, the method quantifies levels among the different quats compounds with high precision (detection limits to capture quats on air sampling filters with only a 15-min sample duration with a maximum assessed storage time of 103 days before sample extraction. This method will support future exposure assessment and quantitative epidemiologic studies to explore exposure-response relationships and establish levels of quats exposures associated with adverse health effects. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Sequence-specific capture of protein-DNA complexes for mass spectrometric protein identification.

Directory of Open Access Journals (Sweden)

Cheng-Hsien Wu

Full Text Available The regulation of gene transcription is fundamental to the existence of complex multicellular organisms such as humans. Although it is widely recognized that much of gene regulation is controlled by gene-specific protein-DNA interactions, there presently exists little in the way of tools to identify proteins that interact with the genome at locations of interest. We have developed a novel strategy to address this problem, which we refer to as GENECAPP, for Global ExoNuclease-based Enrichment of Chromatin-Associated Proteins for Proteomics. In this approach, formaldehyde cross-linking is employed to covalently link DNA to its associated proteins; subsequent fragmentation of the DNA, followed by exonuclease digestion, produces a single-stranded region of the DNA that enables sequence-specific hybridization capture of the protein-DNA complex on a solid support. Mass spectrometric (MS analysis of the captured proteins is then used for their identification and/or quantification. We show here the development and optimization of GENECAPP for an in vitro model system, comprised of the murine insulin-like growth factor-binding protein 1 (IGFBP1 promoter region and FoxO1, a member of the forkhead rhabdomyosarcoma (FoxO subfamily of transcription factors, which binds specifically to the IGFBP1 promoter. This novel strategy provides a powerful tool for studies of protein-DNA and protein-protein interactions.

An investigation of the reaction mechanism for resonance neutron capture in 54Fe and 62Ni

International Nuclear Information System (INIS)

Mason, J.P.

1986-01-01

The gamma-ray spectra produced following neutron capture in the low energy resonances of 54 Fe and 62 Ni have been observed, using the Harwell 136 MeV electron linear accelerator facility, HELIOS, as a source of pulsed neutrons. The work indicated that, for s-wave capture in the mass region A approx. 55, single particle effects may only be apparent if the size of the valence component is about an order of magnitude larger than the compound nuclear component, and that this may limit the importance of such effects to a few nuclides. In addition, some information was obtained on the radiative decay of p-wave resonances of 54 Fe and 62 Ni. (author)

Analysis of Protein-Phenolic Compound Modifications Using Electrochemistry Coupled to Mass Spectrometry.

Science.gov (United States)

Kallinich, Constanze; Schefer, Simone; Rohn, Sascha

2018-01-29

In the last decade, electrochemical oxidation coupled with mass spectrometry has been successfully used for the analysis of metabolic studies. The application focused in this study was to investigate the redox potential of different phenolic compounds such as the very prominent chlorogenic acid. Further, EC/ESI-MS was used as preparation technique for analyzing adduct formation between electrochemically oxidized phenolic compounds and food proteins, e.g., alpha-lactalbumin or peptides derived from a tryptic digestion. In the first step of this approach, two reactant solutions are combined and mixed: one contains the solution of the digested protein, and the other contains the phenolic compound of interest, which was, prior to the mixing process, electrochemically transformed to several oxidation products using a boron-doped diamond working electrode. As a result, a Michael-type addition led to covalent binding of the activated phenolic compounds to reactive protein/peptide side chains. In a follow-up approach, the reaction mix was further separated chromatographically and finally detected using ESI-HRMS. Compound-specific, electrochemical oxidation of phenolic acids was performed successfully, and various oxidation and reaction products with proteins/peptides were observed. Further optimization of the reaction (conditions) is required, as well as structural elucidation concerning the final adducts, which can be phenolic compound oligomers, but even more interestingly, quite complex mixtures of proteins and oxidation products.

Study of cyclization of chelating compounds using electrospray ionization mass spectrometry

International Nuclear Information System (INIS)

Shi Ying; Campbell, J.A.

2000-01-01

Electrospray ionization mass spectrometry (ESI-MS) was used for the study of cyclization of organic chelating compounds (chelators). Four chelating compounds were studied: Symmetrical ethylenediaminediacetic acid (s-EDDA), Unsymmetrical ethylenediaminediacetic acid (u-EDDA), N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), and N-(2-hydroxyethyl)iminodiacetic acid (HEIDA). The chelators were cyclized with treatments of acids and heating. The open and cyclized form of the chelators were semi-quantified by both positive and negative ion modes ESI-MS. The kinetics of chelator cyclization was studied as a function of reaction temperature and the pH of the matrix. The cyclization of s-EDDA was found to be a pseudo-first order reaction in s-EDDA and overall second order. The cyclizations of HEIDA and HEDTA are reversible reactions. Higher temperature and lower pH favors cyclization. (author)

Data on coffee composition and mass spectrometry analysis of mixtures of coffee related carbohydrates, phenolic compounds and peptides

Directory of Open Access Journals (Sweden)

Ana S.P. Moreira

2017-08-01

Full Text Available The data presented here are related to the research paper entitled “Transglycosylation reactions, a main mechanism of phenolics incorporation in coffee melanoidins: inhibition by Maillard reaction” (Moreira et al., 2017 [1]. Methanolysis was applied in coffee fractions to quantify glycosidically-linked phenolics in melanoidins. Moreover, model mixtures mimicking coffee beans composition were roasted and analyzed using mass spectrometry-based approaches to disclose the regulatory role of proteins in transglycosylation reactions extension. This article reports the detailed chemical composition of coffee beans and derived fractions. In addition, it provides gas chromatography–mass spectrometry (GC–MS chromatograms and respective GC–MS spectra of silylated methanolysis products obtained from phenolic compounds standards, as well as the detailed identification of all compounds observed by electrospray mass spectrometry (ESI-MS analysis of roasted model mixtures, paving the way for the identification of the same type of compounds in other samples.

Using fragmentation trees and mass spectral trees for identifying unknown compounds in metabolomics.

Science.gov (United States)

Vaniya, Arpana; Fiehn, Oliver

2015-06-01

Identification of unknown metabolites is the bottleneck in advancing metabolomics, leaving interpretation of metabolomics results ambiguous. The chemical diversity of metabolism is vast, making structure identification arduous and time consuming. Currently, comprehensive analysis of mass spectra in metabolomics is limited to library matching, but tandem mass spectral libraries are small compared to the large number of compounds found in the biosphere, including xenobiotics. Resolving this bottleneck requires richer data acquisition and better computational tools. Multi-stage mass spectrometry (MSn) trees show promise to aid in this regard. Fragmentation trees explore the fragmentation process, generate fragmentation rules and aid in sub-structure identification, while mass spectral trees delineate the dependencies in multi-stage MS of collision-induced dissociations. This review covers advancements over the past 10 years as a tool for metabolite identification, including algorithms, software and databases used to build and to implement fragmentation trees and mass spectral annotations.

Reaction of low-molecular-mass organoselenium compounds (and their sulphur analogues) with inflammation-associated oxidants

DEFF Research Database (Denmark)

Carroll, L.; Davies, Michael J.; Pattison, D. I.

2015-01-01

Selenium is an essential trace element in mammals, with the majority specifically encoded as seleno-L-cysteine into a range of selenoproteins. Many of these proteins play a key role in modulating oxidative stress, via either direct detoxification of biological oxidants, or repair of oxidised...... the chemistry of low-molecular-mass organoselenium compounds (e.g. selenoethers, diselenides and selenols) with inflammatory oxidants, with a particular focus on the reaction kinetics and product studies, with the differences in reactivity between selenium and sulphur analogues described in the selected...... examples. These data provide insight into the therapeutic potential of low-molecular-mass selenium-containing compounds to modulate the activity of both radical and molecular oxidants and provide protection against inflammation-induced damage. Progress in their therapeutic development (including modulation...

Determination of high molecular mass compounds from Amazonian plant's leaves

International Nuclear Information System (INIS)

Siqueira, Denilson Soares de; Pereira, Alberto dos Santos; Aquino Neto, Francisco Radler de; Simoneit, Bernd R.T.

2003-01-01

The fractions of dichloromethane extracts of leaves from andiroba (Carapa guianensis - Meliaceae), caapi (Banisteriopsis caapi - Malpighiaceae), cocoa (Theobroma cacao - Sterculiaceae), Brazil nut (Bertholletia excelsa - Lecytidaceae), cupuacu (Theobroma grandiflorum - Sterculiaceae), marupa (Simaruba amara - Simaroubaceae) and rubber tree (Hevea brasiliensis - Euphorbiaceae), were analyzed by HT-HRGC and HT-HRGC-MS. Esters of homologous series of fatty acids and long chain alcohols, phytol, amyrines and tocopherols were characterized. The characterization of the compounds was based mainly in mass spectra data and in addition by usual spectrometric data ( 1 H and 13 C NMR, IR). (author)

Enhancing Protein Disulfide Bond Cleavage by UV Excitation and Electron Capture Dissociation for Top-Down Mass Spectrometry

OpenAIRE

Wongkongkathep, Piriya; Li, Huilin; Zhang, Xing; Loo, Rachel R. Ogorzalek; Julian, Ryan R.; Loo, Joseph A.

2015-01-01

The application of ion pre-activation with 266 nm ultraviolet (UV) laser irradiation combined with electron capture dissociation (ECD) is demonstrated to enhance top-down mass spectrometry sequence coverage of disulfide bond containing proteins. UV-based activation can homolytically cleave a disulfide bond to yield two separated thiol radicals. Activated ECD experiments of insulin and ribonuclease A containing three and four disulfide bonds, respectively, were performed. UV-activation in comb...

Organics Captured from Comet Wild 2 by the Stardust Spacecraft

Energy Technology Data Exchange (ETDEWEB)

Stanford, S A; Aleon, J; O' D. Alexander, C M; Araki, T; Bajt, S; Baratta, G A; Borg, J; Brucato, J R; Burchell, M J; Busemann, H; Butterworth, A; Clemett, S J; Cody, G; Colangeli, L; Cooper, G; D' Hendecourt, L; Djouadi, Z; Dworkin, J P; Ferrini, G; Fleckenstein, H; Flynn, G; Franchi, I A; Fries, M; Gilles, M K; Glavin, D P; Gounelle, M; Grossemy, F; Jacobsen, C; Keller, L P; Kilcoyne, A D; Leitner, J; Matrajt, G; Meibom, A; Mennella, V; Mostefaoui, S; Nittler, L R; Palumbo, M E; Robert, F; Rotundi, A; Snead, C J; Spencer, M K; Steele, A; Stephan, T; Tyliszczak, T; Westphal, A J; Wirick, S; Wopenka, B; Yabuta, H; Zare, R N; Zolensky, M

2006-10-11

Organics found in Comet Wild 2 samples show a heterogeneous and unequilibrated distribution in abundance and composition. Some organics are similar, but not identical, to those in interplanetary dust particles (IDPs) and carbonaceous meteorites. A class of aromatic-poor organic material is also present. The organics are rich in O and N compared to meteoritic organics. Aromatic compounds are present, but the samples tend to be relatively poorer in aromatics than meteorites and IDPs. D and {sup 15}N suggest that some organics have an interstellar/protostellar heritage. While the variable extent of modification of these materials by impact capture is not yet fully constrained, a remarkably diverse suite of organic compounds is present and identifiable within the returned samples. Comets are small bodies that accreted in the outer Solar System during its formation (1) and thus may consist of preserved samples of the ''starting materials'' from which the Solar System was made. Organic materials are expected to be present in cometary samples (2) and may include molecules made and/or modified in stellar outflows, the interstellar medium, and the protosolar nebula, as well as by parent body processing within the comet. The presence of organic compounds in comets and their ejecta is of astrobiological interest since their delivery to the early Earth may have played an important role in the origin of life on Earth (3). An overview of the Stardust Mission and the collection and recovery of Wild 2 samples is provided elsewhere (4,5). We describe the results obtained from the returned samples by the Stardust Organics Preliminary Examination Team (PET). Samples were studied using a wide range of analytical techniques, including two-step laser desorption laser ionization mass spectrometry (L{sub 2}MS), Liquid Chromatography with UV Fluorescence Detection and Time of Flight Mass Spectrometry (LC-FD/TOF-MS), Scanning Transmission X-ray Microscopy (STXM), X

Approaches towards the automated interpretation and prediction of electrospray tandem mass spectra of non-peptidic combinatorial compounds.

Science.gov (United States)

Klagkou, Katerina; Pullen, Frank; Harrison, Mark; Organ, Andy; Firth, Alistair; Langley, G John

2003-01-01

Combinatorial chemistry is widely used within the pharmaceutical industry as a means of rapid identification of potential drugs. With the growth of combinatorial libraries, mass spectrometry (MS) became the key analytical technique because of its speed of analysis, sensitivity, accuracy and ability to be coupled with other analytical techniques. In the majority of cases, electrospray mass spectrometry (ES-MS) has become the default ionisation technique. However, due to the absence of fragment ions in the resulting spectra, tandem mass spectrometry (MS/MS) is required to provide structural information for the identification of an unknown analyte. This work discusses the first steps of an investigation into the fragmentation pathways taking place in electrospray tandem mass spectrometry. The ultimate goal for this project is to set general fragmentation rules for non-peptidic, pharmaceutical, combinatorial compounds. As an aid, an artificial intelligence (AI) software package is used to facilitate interpretation of the spectra. This initial study has focused on determining the fragmentation rules for some classes of compound types that fit the remit as outlined above. Based on studies carried out on several combinatorial libraries of these compounds, it was established that different classes of drug molecules follow unique fragmentation pathways. In addition to these general observations, the specific ionisation processes and the fragmentation pathways involved in the electrospray mass spectra of these systems were explored. The ultimate goal will be to incorporate our findings into the computer program and allow identification of an unknown, non-peptidic compound following insertion of its ES-MS/MS spectrum into the AI package. The work herein demonstrates the potential benefit of such an approach in addressing the issue of high-throughput, automated MS/MS data interpretation. Copyright 2003 John Wiley & Sons, Ltd.

Identification of volatile and semivolatile compounds in chemical ionization GC-MS using a mass-to-structure (MTS) Search Engine with integral isotope pattern ranking.

Science.gov (United States)

Liao, Wenta; Draper, William M

2013-02-21

The mass-to-structure or MTS Search Engine is an Access 2010 database containing theoretical molecular mass information for 19,438 compounds assembled from common sources such as the Merck Index, pesticide and pharmaceutical compilations, and chemical catalogues. This database, which contains no experimental mass spectral data, was developed as an aid to identification of compounds in atmospheric pressure ionization (API)-LC-MS. This paper describes a powerful upgrade to this database, a fully integrated utility for filtering or ranking candidates based on isotope ratios and patterns. The new MTS Search Engine is applied here to the identification of volatile and semivolatile compounds including pesticides, nitrosoamines and other pollutants. Methane and isobutane chemical ionization (CI) GC-MS spectra were obtained from unit mass resolution mass spectrometers to determine MH(+) masses and isotope ratios. Isotopes were measured accurately with errors of Search Engine and details performance testing with over 50 model compounds.

Preparation of a radioactive boron compound (B-I-131-lipiodol) for neutron capture therapy of hepatoma

International Nuclear Information System (INIS)

Chou, F.I.; Chung, H.P.; Chung, R.J.; Wen, H.W.; Wei, Y.Y.; Kai, J.J.; Lui, W.Y.; Chi, C.W.

2000-01-01

In our research, a radioactive boron compound, B-I-131-lipiodol, that can be selectively retained in hepatoma cells was prepared. Combining the effect of α particles produced by boron neutron capture reaction with the β particles released by radionuclides in the radioactive boron compounds will produce a synergistic killing effect on cancer cells. Human hepatoma HepG2 cell cultures were used to examine the stability and the intracellular distribution of the radioactive boron drug. Microscopes were used to examine the interaction and retention of B-I-131-lipiodol globules in the individual hepatoma cell. Moreover, ICP-AES and NaI scintillation counter were performed to determine boron concentrations and I-131 radioactivity, respectively. Results showed that B-I-131-lipiodol with a boron concentration and a specific radioactivity ranged from 500-2000 ppm and 0.05-10 mCi/mL respectively was stably retained in serum. The radiochemical purity of B-I-131-lipiodol was 98%. After supplement with a medium containing B-I-131-lipiodol, the HepG2 cells had intracellular B-I-131-lipiodol globules in the cytoplasm as seen by inverted light microscope, the I-131 and boron can be stably retained in HepG2 cells. (author)

Formation of double galaxies by tidal capture

International Nuclear Information System (INIS)

Alladin, S.M.; Potdar, A.; Sastry, K.S.

1975-01-01

The conditions under which double galaxies may be formed by tidal capture are considered. Estimates for the increase in the internal energy of colliding galaxies due to tidal effects are used to determine the magnitudes Vsub(cap) and Vsub(dis) of the maximum relative velocities at infinite separation required for tidal capture and tidal disruption respectively. A double galaxy will be formed by tidal capture without tidal disruption of a component if Vsub(cap)>Vsub(i) and Vsub(cap)>Vsub(dis) where Vsub(i) is the initial relative speed of the two galaxies at infinite separation. If the two galaxies are of the same dimension, formulation of double galaxies by tidal capture is possible in a close collision either if the two galaxies do not differ much in mass and density distribution or if the more massive galaxy is less centrally concentrated than the other. If it is assumed as statistics suggest, that the mass of a galaxy is proportional to the square of its radius, it follows that the probability of the formation of double galaxies by tidal capture increases with the increase in mass of the galaxies and tidal distribution does not occur in a single collision for any distance of closest approach of the two galaxies. (Auth.)

Data on volatile compounds in fermented materials used for salmon fish sauce production.

Science.gov (United States)

Nakano, Mitsutoshi; Sagane, Yoshimasa; Koizumi, Ryosuke; Nakazawa, Yozo; Yamazaki, Masao; Watanabe, Toshihiro; Takano, Katsumi; Sato, Hiroaki

2018-02-01

This article describes the analysis of volatile compounds in fermented materials used for salmon fish sauce production via gas chromatography/mass spectrometry (GC/MS). Ten types of fish sauces were produced from raw salmon materials, including various proportions of flesh, viscera, inedible portion (heads, fins, and backbones), and soft roe, by mixing them with salt and allowing them to ferment for up to three months. The volatile compounds were captured by a solid-phase microextraction method and then applied to GC/MS for separation and identification of the compounds in the fish sauce products. The number of volatile compounds identified in the starting materials varied from 15 to 29 depending on the ingredients. The number of compounds in the final fish sauce products was reduced by 3.4-94.7% of that in the original material. The retention times and names of the identified compounds, as well as their relative peak areas, are provided in a Microsoft Excel Worksheet.

Identification of novel synthetic organic compounds with supersonic gas chromatography-mass spectrometry.

Science.gov (United States)

Fialkov, Alexander B; Amirav, Aviv

2004-11-26

Several novel synthetic organic compounds were successfully analyzed with a unique type of GC-MS titled Supersonic GC-MS following a failure in their analysis with standard GC-MS. Supersonic GC-MS is based on interfacing GC and MS with a supersonic molecular beam (SMB) and on electron ionization of sample compounds as vibrationally cold molecules while in the SMB, or by cluster chemical ionization. The analyses of novel synthetic organic compounds significantly benefited from the extended range of compounds amenable to analyses with the Supersonic GC-MS. The Supersonic GC-MS enabled the analysis of thermally labile compounds that usually degrade in the GC injector, column and/or ion source. Due to the high carrier gas flow rate at the injector liner and column these compounds eluted without degradation at significantly lower elution temperatures and the use of fly-through EI ion source eliminated any sample degradation at the ion source. The cold EI feature of providing trustworthy enhanced molecular ion (M+), complemented by its optional further confirmation with cluster CI was highly valued by the synthetic organic chemists that were served by the Supersonic GC-MS. Furthermore, the provision of extended mass spectral structural, isomer and isotope information combined with short (a few minutes) GC-MS analysis times also proved beneficial for the analysis of unknown synthetic organic compounds. As a result, the synthetic organic chemists were provided with both qualitative and quantitative data on the composition of their synthetic mixture, and could better follow the path of their synthetic chemistry. Ten cases of such analyses are demonstrated in figures and discussed.

Electron-capture and Low-mass Iron-core-collapse Supernovae: New Neutrino-radiation-hydrodynamics Simulations

Science.gov (United States)

Radice, David; Burrows, Adam; Vartanyan, David; Skinner, M. Aaron; Dolence, Joshua C.

2017-11-01

We present new 1D (spherical) and 2D (axisymmetric) simulations of electron-capture (EC) and low-mass iron-core-collapse supernovae (SN). We consider six progenitor models: the ECSN progenitor from Nomoto; two ECSN-like low-mass low-metallicity iron-core progenitors from A. Heger (2016, private communication); and the 9, 10, and 11 {M}⊙ (zero-age main-sequence) progenitors from Sukhbold et al. We confirm that the ECSN and ESCN-like progenitors explode easily even in 1D with explosion energies of up to a 0.15 Bethes (1 {{B}}\\equiv {10}51 {erg}), and are a viable mechanism for the production of very-low-mass neutron stars. However, the 9, 10, and 11 {M}⊙ progenitors do not explode in 1D and are not even necessarily easier to explode than higher-mass progenitor stars in 2D. We study the effect of perturbations and of changes to the microphysics and we find that relatively small changes can result in qualitatively different outcomes, even in 1D, for models sufficiently close to the explosion threshold. Finally, we revisit the impact of convection below the protoneutron star (PNS) surface. We analyze 1D and 2D evolutions of PNSs subject to the same boundary conditions. We find that the impact of PNS convection has been underestimated in previous studies and could result in an increase of the neutrino luminosity by up to factors of two.

Determination of heat purgeable and ambient purgeable volatile organic compounds in water by gas chromatography/mass spectrometry

Science.gov (United States)

Rose, Donna L.; Sandstrom, Mark W.; Murtagh, Lucinda K.

2016-09-08

Two new analytical methods have been developed by the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) that allow the determination of 37 heat purgeable volatile organic compounds (VOCs) (USGS Method O-4437-16 [NWQL Laboratory Schedule (LS) 4437]) and 49 ambient purgeable VOCs (USGS Method O-4436-16 [NWQL LS 4436]) in unfiltered water. This report documents the procedures and initial performance of both methods. The compounds chosen for inclusion in the methods were determined as having high priority by the USGS National Water-Quality Assessment (NAWQA) Program. Both methods use a purge-and-trap technique with gas chromatography/mass spectrometry. The compounds are extracted from the sample by bubbling helium through a 25-milliliter sample. For the polar and less volatile compounds, the sample is heated at 60 degrees Celsius, whereas the less polar and more volatile compounds are purged using a separate analytical procedure at ambient temperature. The compounds are trapped on a sorbent trap, desorbed into a gas chromatograph/mass spectrometer for separation, and then identified and quantified. Sample preservation is recommended for both methods by adding a 1:1 solution of hydrochloric acid (HCl [1:1]) to water samples to adjust the pH to 2. Analysis within 14 days from sampling is recommended.The heat purgeable method (USGS Method O-4437-16) operates with the mass spectrometer in the simultaneous full scan/selected ion monitoring mode. This method supersedes USGS Method O-4024-03 (NWQL LS 4024). Method detection limits (MDLs) for fumigant compounds 1,2-dibromoethane, 1,2-dichloropropane, 1,2,3-trichloropropane, chloropicrin, and 1,2-dibromo-3-chloropropane range from 0.002 to 0.010 microgram per liter (µg/L). The MDLs for all remaining heat purgeable VOCs range from 0.006 µg/L for tert-butyl methyl ether to 3 µg/L for alpha-terpineol. Calculated holding times indicate that 36 of the 37 heat purgeable VOCs are stable for a minimum of 14 days

Rapid identification and quantitation of compounds with forensic interest using fast liquid chromatography-ion trap mass spectrometry and library searching.

Science.gov (United States)

Pihlainen, Katja; Sippola, Erkki; Kostiainen, Risto

2003-04-25

A fast liquid chromatography-electrospray tandem mass spectrometric (LC-ESI-MS-MS) method by using a monolithic column, gradient elution and ion trap mass spectrometer was developed for 14 forensically interesting and chemically different compounds. All compounds were eluted within 2.5 min and the total analysis time was 5 min including stabilisation time required for the next injection. All the compounds, basics, neutrals and acids were efficiently ionised by positive ion ESI. A laboratory library including MS-MS spectra and retention times was developed and tested. Results with 476 standard samples and 50 authentic samples showed that the compounds studied can be unambiguously identified with the library. A quantitative method was developed for the compounds using external calibration. The evaluation process showed good linearity of the method and reasonable repeatability. Limits of detection ranged from 10.0 to 50.0 ng/ml.

Chromatography mass spectrometry and its use in identification in the radiolysis products of polycyclic aromatic hydrocarbons and organic compounds

International Nuclear Information System (INIS)

Ibadov, N.A.; Suleymanov, B.A.

2010-01-01

Full text : Increased attention to the environment is the result of dramatically increased human activity, which in turn is caused by the rapid growth of population of the planet. Extremely powerful tool for control of pollution of different environmental objects - Chromatographic methods to analyze complex mixtures of components. This work is devoted to methods of gas chromatography - mass - spectroscopy and its use in identifying the pollutants of natural environments. Devices that allow obtaining the mass spectra are called mass spectrometers. Sensitivity of gas chromatography-mass spectrometry (typically 10-6-10-9 g) determined by the sensitivity of the mass spectrometer detector. Its essence lies in the fact that the recording of chromatograms is not the full ion current and the most characteristic ions of the substance. With varying degrees of probability in the water identified over 100 individual organic compounds, including PHs. The method of gas chromatography-mass spectrometry identified compounds in natural waters, soils, soil and sediments.

Atmospheric pressure ionization-tandem mass spectrometry of the phenicol drug family.

Science.gov (United States)

Alechaga, Élida; Moyano, Encarnación; Galceran, M Teresa

2013-11-01

In this work, the mass spectrometry behaviour of the veterinary drug family of phenicols, including chloramphenicol (CAP) and its related compounds thiamphenicol (TAP), florfenicol (FF) and FF amine (FFA), was studied. Several atmospheric pressure ionization sources, electrospray (ESI), atmospheric pressure chemical ionization and atmospheric pressure photoionization were compared. In all atmospheric pressure ionization sources, CAP, TAP and FF were ionized in both positive and negative modes; while for the metabolite FFA, only positive ionization was possible. In general, in positive mode, [M + H](+) dominated the mass spectrum for FFA, while the other compounds, CAP, TAP and FF, with lower proton affinity showed intense adducts with species present in the mobile phase. In negative mode, ESI and atmospheric pressure photoionization showed the deprotonated molecule [M-H](-), while atmospheric pressure chemical ionization provided the radical molecular ion by electron capture. All these ions were characterized by tandem mass spectrometry using the combined information obtained by multistage mass spectrometry and high-resolution mass spectrometry in a quadrupole-Orbitrap instrument. In general, the fragmentation occurred via cyclization and losses or fragmentation of the N-(alkyl)acetamide group, and common fragmentation pathways were established for this family of compounds. A new chemical structure for the product ion at m/z 257 for CAP, on the basis of the MS(3) and MS(4) spectra is proposed. Thermally assisted ESI and selected reaction monitoring are proposed for the determination of these compounds by ultra high-performance liquid chromatography coupled to tandem mass spectrometry, achieving instrumental detection limits down to 0.1 pg. Copyright © 2013 John Wiley & Sons, Ltd.

Temperature-dependent release of volatile organic compounds of eucalypts by direct analysis in real time (DART) mass spectrometry.

Science.gov (United States)

Maleknia, Simin D; Vail, Teresa M; Cody, Robert B; Sparkman, David O; Bell, Tina L; Adams, Mark A

2009-08-01

A method is described for the rapid identification of biogenic, volatile organic compounds (VOCs) emitted by plants, including the analysis of the temperature dependence of those emissions. Direct analysis in real time (DART) enabled ionization of VOCs from stem and leaf of several eucalyptus species including E. cinerea, E. citriodora, E. nicholii and E. sideroxylon. Plant tissues were placed directly in the gap between the DART ionization source skimmer and the capillary inlet of the time-of-flight (TOF) mass spectrometer. Temperature-dependent emission of VOCs was achieved by adjusting the temperature of the helium gas into the DART ionization source at 50, 100, 200 and 300 degrees C, which enabled direct evaporation of compounds, up to the onset of pyrolysis of plant fibres (i.e. cellulose and lignin). Accurate mass measurements facilitated by TOF mass spectrometry provided elemental compositions for the VOCs. A wide range of compounds was detected from simple organic compounds (i.e. methanol and acetone) to a series of monoterpenes (i.e. pinene, camphene, cymene, eucalyptol) common to many plant species, as well as several less abundant sesquiterpenes and flavonoids (i.e. naringenin, spathulenol, eucalyptin) with antioxidant and antimicrobial properties. The leaf and stem tissues for all four eucalypt species showed similar compounds. The relative abundances of methanol and ethanol were greater in stem wood than in leaf tissue suggesting that DART could be used to investigate the tissue-specific transport and emissions of VOCs. Copyright (c) 2009 John Wiley & Sons, Ltd.

Regiospecific analysis of neutral ether lipids by liquid chromatography/electrospray ionization/single quadrupole mass spectrometry: validation with synthetic compounds

DEFF Research Database (Denmark)

Hartvigsen, Karsten; Ravandi, A.; Bukhave, Klaus

2001-01-01

A reversed-phase high-performance liquid chromatography (HPLC) method with on-line electrospray ionization/collision-induced dissociation/mass spectrometry (ESI/CID/MS) is presented for the regiospecific analysis of synthetic reference compounds of neutral ether lipids. The reference compounds were...... characterized by chromatographic retention times, full mass spectra, and fragmentation patterns as an aid to clarify the regiospecificity of ether lipids from natural sources. The results clearly show that single quadrupole mass spectroscopic analysis may elucidate the regiospecific structure of neutral ether...... + H - H2O](+), whereas the reverse situation characterized the sn-3 species. Furthermore, corresponding sn-2 and sn-3 species were separated by the chromatographic system. However, loss of water was promoted as fatty acid unsaturation was raised, which may complicate interpretation of the mass spectra...

Precision mass measurements for studies of nucleosynthesis via the rapid neutron-capture process Penning-trap mass measurements of neutron-rich cadmium and caesium isotopes

CERN Document Server

AUTHOR|(CDS)2085660; Litvinov, Yuri A.; Kreim, Susanne

Although the theory for the rapid neutron-capture process (r-process) was developed more than 55 years ago, the astrophysical site is still under a debate. Theoretical studies predict that the r-process path proceeds through very neutron-rich nuclei with very asymmetric proton- to-neutron ratios. Knowledge about the properties of neutron-rich isotopes found in similar regions of the nuclear chart and furthermore suitable for r-process studies is still little or even not existing. The basic nuclear properties such as binding energies, half-lives, neutron-induced or neutron-capture reaction cross-sections, play an important role in theoretical simulations and can vary or even drastically alternate results of these studies. Therefore, a considerable effort was put forward to access neutron-rich isotopes at radioactive ion-beam facilities like ISOLDE at CERN. The goal of this PhD thesis is to describe the experimental work done for the precision mass measurements of neutron-rich cadmium (129−131 Cd) and caesium...

New compounds for neutron capture therapy (NCT) and their significance

International Nuclear Information System (INIS)

Fairchild, R.G.; Bond, V.P.

1982-01-01

Clearly the most effective tumor therapy would be obtained by the selective targeting of cytotoxic agents to tumor cells. Although many biomolecules are known to be taken up in tumors, the targeting of cytotoxic agents to tumors is limited by the fact that other essential cell pools compete with equal or even greater effectiveness. The approach of delivering stable non-toxic isotopes to tumor, with activation by means of an external radiation beam, is advantageous for two reasons: (1) it obviates problems associated with high uptake of isotopes in normal tissues, as these cell pools can be excluded from the radiation field, and (2) the general tumor area can be included in the activating beam field; thus, the possibility exists that all microscopic tumor extensions can be irradiated. As long as range of reaction products is short, dose will be restricted to the tumor, with a resultant high therapeutic ratio. This method can be accomplished with either photon activation therapy (PAT) or Neutron Capture Therapy (NCT), the latter will be emphasized here. The range of the high LET, low OER particles from the 10 B(n,α) 7 Li reaction is approx. 10 μm, or one cell diameter; hence this reaction is optimal for cell killing. A number of biomolecules have been investigated as possible vehicles for transport of boron to tumors, including phenothiazines, thiouracils, porphyrins, nucleosides, and amino acids. Biodistributions of these compounds show selective concentration in tumor adequate for therapy. The biological halflives are in the order of days, allowing the possibility of fractionated or protracted irradiations. The radiobiological and physical implication of these parameters on NCT are discussed. The possibility of using an approximately-monoenergetic, scandium-filtered beam of about 2 keV, to reduce the dose from background radiations by about 85%, is also discussed

Sulphur-containing compounds in the essential oil of Ferula alliacea roots and their mass spectral fragmentation patterns.

Science.gov (United States)

Kasaian, Jamal; Asili, Javad; Iranshahi, Mehrdad

2016-10-01

Context GC-MS analysis is the best way to characterize volatile sulphur-containing compounds. Ferula (Apiaceae) is a genus of perennial herbs. Due to the occurrence of essential oils or oleoresins in the Ferula species, these plants usually possess strong aromatic scent. Terpenoid compounds were the most abundant constituents of Ferula oils, however, in some of Ferula species, the essential oils were dominated by volatile sulphur-containing compounds. Objectives Ferula alliacea Boiss. is considered one of the sources of the oleo-gum-resin asafoetida. In this study, we analyzed the hydrodistilled essential oil from its dried roots and provide new data about retention indices and mass fragmentation patterns of some volatile sulphur-containing compounds that are useful for future studies on this class of compounds. Materials and methods The roots of F. alliacea were collected during the flowering stage of plant, from Bezgh, Kashmar to Neishabour road, Khorasan-Razavi province, Iran, in June 2012. The oil was obtained by hydrodistillation using a Clevenger apparatus and analyzed by GC-MS. Results This is the first report on phytochemical analysis of F. alliacea roots. Seventy-six components, representing 99.5% of the oil, were characterized. The major components were 10-epi-γ-eudesmol (22.3%), valerianol (12.5%), hinesol (8.3%), guaiol (7.3%) and Z-propenyl-sec-butyl trisulphide (6.5%). Predominant mass fragment ions of the identified sulphur-containing compounds are explained in this paper. Conclusion The volatile oil of F. alliacea mostly contains oxygenated sesquiterpenes, however, its odour was dominated by sulphur-containing compounds. The most abundant sulphur-containing compound includes Z-propenyl-sec-butyl trisulphide (6.5%).

Capture of terrestrial-sized moons by gas giant planets.

Science.gov (United States)

Williams, Darren M

2013-04-01

Terrestrial moons with masses >0.1 M (symbol in text) possibly exist around extrasolar giant planets, and here we consider the energetics of how they might form. Binary-exchange capture can occur if a binary-terrestrial object (BTO) is tidally disrupted during a close encounter with a giant planet and one of the binary members is ejected while the other remains as a moon. Tidal disruption occurs readily in the deep gravity wells of giant planets; however, the large encounter velocities in the wells make binary exchange more difficult than for planets of lesser mass. In addition, successful capture favors massive binaries with large rotational velocities and small component mass ratios. Also, since the interaction tends to leave the captured moons on highly elliptical orbits, permanent capture is only possible around planets with sizable Hill spheres that are well separated from their host stars.

Study by mass spectrometry of the formation of cluster ions generated by laser ablation/ionization of inorganic compounds: application to the differentiation of trivalent and hexavalent chromium compounds

International Nuclear Information System (INIS)

Aubriet, Frederic

1999-01-01

The introduction of new ionization techniques allows a fast growth of mass spectrometry applications in an increasing number of fields. More particularly, the introduction of laser ablation/ionization process and the design of new instruments (laser microprobes), has been very important for a better knowledge of inorganic compound mass spectrometry. The purposes of this work were mainly focussed firstly in the understanding of cluster ions formation process by laser ablation/ionization and secondly in the development of a new mass spectrometry technique for the speciation between trivalent and hexavalent chromium compounds. We show that cluster ion formation are multiple. The difficulty to identify clearly the processes involved is due to the superposition of many mechanisms. Mostly, these processes are representative of the complexity of the gas-phase chemistry between the various species generated by laser ablation/ionization. Thus, four mechanisms for the cluster ion formation have been highlighted. The most frequently met correspond to aggregative processes of neutral molecules on precursor ions. The knowledge of the processes of cluster ion formation allows us to explain why it is possible to distinguish the oxidation number of chromium. The organigram of chromium valence speciation proposed is based on the calculation of the ratio of negative cluster ion intensities after systematic analysis of nearly twenty chromium reference compounds using the same instrumental conditions. The examination of mixtures between 1) calcium. silicon, trivalent iron or zinc oxides and 2) the standard chromium compound allows us to observe the influence of these oxides on the fingerprints of the pure chromium compounds and to determine up to which point and with which limitations, the methodology suggested, could be applied to the analysis of trivalent and hexavalent chromium compounds in complex and polyphasic matrices

Approaches for the analysis of low molecular weight compounds with laser desorption/ionization techniques and mass spectrometry.

Science.gov (United States)

Bergman, Nina; Shevchenko, Denys; Bergquist, Jonas

2014-01-01

This review summarizes various approaches for the analysis of low molecular weight (LMW) compounds by different laser desorption/ionization mass spectrometry techniques (LDI-MS). It is common to use an agent to assist the ionization, and small molecules are normally difficult to analyze by, e.g., matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) using the common matrices available today, because the latter are generally small organic compounds themselves. This often results in severe suppression of analyte peaks, or interference of the matrix and analyte signals in the low mass region. However, intrinsic properties of several LDI techniques such as high sensitivity, low sample consumption, high tolerance towards salts and solid particles, and rapid analysis have stimulated scientists to develop methods to circumvent matrix-related issues in the analysis of LMW molecules. Recent developments within this field as well as historical considerations and future prospects are presented in this review.

Qualitative screening of undesirable compounds from feeds to fish by liquid chromatography coupled to mass spectrometry.

Science.gov (United States)

Nácher-Mestre, Jaime; Ibáñez, María; Serrano, Roque; Pérez-Sánchez, Jaume; Hernández, Félix

2013-03-06

This paper describes the development, validation, and application of a rapid screening method for the detection and identification of undesirable organic compounds in aquaculture products. A generic sample treatment was applied without any purification or preconcentration step. After extraction of the samples with acetonitrile/water 80:20 (0.1% formic acid), the extracts were centrifuged and directly injected in the LC-HRMS system, consisting of ultra-high performance liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). A qualitative validation was carried out for over 70 representative compounds, including antibiotics, pesticides, and mycotoxins, in fish feed and fish fillets spiked at 20 and 100 μg/kg. At the highest level, the great majority of compounds were detected (using the most abundant ion, typically the protonated molecule) and unequivocally identified (on the basis of the presence of two accurate-mass measured ions). At the 20 μg/kg level, many contaminants could already be detected, although identification using two ions was not fully reached for some of them, mainly in fish feed due to the complexity of this matrix. Subsequent application of this screening methodology to aquaculture samples made it possible to find several compounds from the target list, such as the antibiotic ciprofloxacin, the insecticide pirimiphos-methyl, and the mycotoxins fumonisin B2 and zearalenone. A retrospective analysis of accurate-mass full-spectrum acquisition data provided by QTOF MS was also made, without either reprocessing or injecting the samples. This allowed the detection and tentative identification of other organic undesirables different from those included in the validated list.

Profiling of volatile organic compounds produced by clinical Aspergillus isolates using gas chromatography-mass spectrometry

NARCIS (Netherlands)

Gerritsen, M G; Brinkman, P; Escobar Salazar, Natalia; Bos, L D; de Heer, K; Meijer, M; Janssen, H-G; de Cock, H; Wösten, H A B; Visser, C.E.; van Oers, M H J; Sterk, P J

Volatile organic compounds (VOCs) in exhaled breath may identify the presence of invasive pulmonary aspergillosis. We aimed to detect VOC profiles emitted by in vitro cultured, clinical Aspergillus isolates using gas chromatography-mass spectrometry (GC-MS). Three clinical Aspergillus isolates and a

Profiling of volatile organic compounds produced by clinical Aspergillus isolates using gas chromatography-mass spectrometry

NARCIS (Netherlands)

Gerritsen, M. G.; Brinkman, P.; Escobar, N.; Bos, L. D.; de Heer, K.; Meijer, M.; Janssen, H.-G.; de Cock, H.; Wösten, H. A. B.; Visser, C. E.; van Oers, M. H. J.; Sterk, P. J.

2018-01-01

Volatile organic compounds (VOCs) in exhaled breath may identify the presence of invasive pulmonary aspergillosis. We aimed to detect VOC profiles emitted by in vitro cultured, clinical Aspergillus isolates using gas chromatography-mass spectrometry (GC-MS). Three clinical Aspergillus isolates and a

Hydrophilic interaction chromatography coupled matrix assisted laser desorption/ionization mass spectrometry for molecular analysis of organic compounds in medicines, tea, and coffee.

Science.gov (United States)

Wang, Ren-Qi; Bao, Kai; Croué, Jean-Philippe; Ng, Siu Choon

2013-11-21

Natural occurring organic compounds from food, natural organic matter, as well as metabolic products have received intense attention in current chemical and biological studies. Examination of unknown compounds in complex sample matrices is hampered by the limited choices for data readout and molecular elucidation. Herein, we report a generic method of hydrophilic interaction chromatography (HILIC) coupled with matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the rapid characterization of ingredients in pharmaceutical compounds, tea, and coffee. The analytes were first fractionated using a cationic HILIC column prior to MALDI-MS analyses. It was found that the retention times of a compound arising from different samples were consistent under the same conditions. Accordingly, molecules can be readily characterized by both the mass and chromatographic retention time. The retention behaviors of acidic and basic compounds on the cationic HILIC column were found to be significantly influenced by the pH of mobile phases, whereas neutral compounds depicted a constant retention time at different pH. The general HILIC-MALDI-MS method is feasible for fast screening of naturally occurring organic compounds. A series of homologs can be determined if they have the same retention behavior. Their structural features can be elucidated by considering their mass differences and hydrophilic properties as determined by HILIC chromatogram.

Analysis of multiple quaternary ammonium compounds in the brain using tandem capillary column separation and high resolution mass spectrometric detection.

Science.gov (United States)

Falasca, Sara; Petruzziello, Filomena; Kretz, Robert; Rainer, Gregor; Zhang, Xiaozhe

2012-06-08

Endogenous quaternary ammonium compounds are involved in various physiological processes in the central nervous system. In the present study, eleven quaternary ammonium compounds, including acetylcholine, choline, carnitine, acetylcarnitine and seven other acylcarnitines of low polarity, were analyzed from brain extracts using a two dimension capillary liquid chromatography-Fourier transform mass spectrometry method. To deal with their large difference in hydrophobicities, tandem coupling between reversed phase and hydrophilic interaction chromatography columns was used to separate all the targeted quaternary ammonium compounds. Using high accuracy mass spectrometry in selected ion monitoring mode, all the compounds could be detected from each brain sample with high selectivity. The developed method was applied for the relative quantification of these quaternary ammonium compounds in three different brain regions of tree shrews: prefrontal cortex, striatum, and hippocampus. The comparative analysis showed that quaternary ammonium compounds were differentially distributed across the three brain areas. The analytical method proved to be highly sensitive and reliable for simultaneous determination of all the targeted analytes from brain samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Capture of free-floating planets by planetary systems

Science.gov (United States)

Goulinski, Nadav; Ribak, Erez N.

2018-01-01

Evidence of exoplanets with orbits that are misaligned with the spin of the host star may suggest that not all bound planets were born in the protoplanetary disc of their current planetary system. Observations have shown that free-floating Jupiter-mass objects can exceed the number of stars in our Galaxy, implying that capture scenarios may not be so rare. To address this issue, we construct a three-dimensional simulation of a three-body scattering between a free-floating planet and a star accompanied by a Jupiter-mass bound planet. We distinguish between three different possible scattering outcomes, where the free-floating planet may get weakly captured after the brief interaction with the binary, remain unbound or 'kick out' the bound planet and replace it. The simulation was performed for different masses of the free-floating planets and stars, as well as different impact parameters, inclination angles and approach velocities. The outcome statistics are used to construct an analytical approximation of the cross-section for capturing a free-floating planet by fitting their dependence on the tested variables. The analytically approximated cross-section is used to predict the capture rate for these kinds of objects, and to estimate that about 1 per cent of all stars are expected to experience a temporary capture of a free-floating planet during their lifetime. Finally, we propose additional physical processes that may increase the capture statistics and whose contribution should be considered in future simulations in order to determine the fate of the temporarily captured planets.

Mass transfer of ammonia escape and CO2 absorption in CO2 capture using ammonia solution in bubbling reactor

International Nuclear Information System (INIS)

Ma, Shuangchen; Chen, Gongda; Zhu, Sijie; Han, Tingting; Yu, Weijing

2016-01-01

Highlights: • Mass transfer coefficient models of ammonia escape were built. • Influences of temperature, inlet CO 2 and ammonia concentration were studied. • Mass transfer coefficients of ammonia escape and CO 2 absorption were obtained. • Studies can provide the basic data as a reference guideline for process application. - Abstract: The mass transfer of CO 2 capture using ammonia solution in the bubbling reactor was studied; according to double film theory, the mass transfer coefficient models and interface area model were built. Through our experiments, the overall volumetric mass transfer coefficients were obtained, while the interface areas in unit volume were estimated. The volumetric mass transfer coefficients of ammonia escaping during the experiment were 1.39 × 10 −5 –4.34 × 10 −5 mol/(m 3 s Pa), and the volumetric mass transfer coefficients of CO 2 absorption were 2.86 × 10 −5 –17.9 × 10 −5 mol/(m 3 s Pa). The estimated interface area of unit volume in the bubbling reactor ranged from 75.19 to 256.41 m 2 /m 3 , making the bubbling reactor a viable choice to obtain higher mass transfer performance than the packed tower or spraying tower.

Boron-Containing Compounds for Liposome-Mediated Tumor Localization and Application to Neutron Capture Therapy

International Nuclear Information System (INIS)

Hawthorne, M. Frederick

2005-01-01

Medical application of boron neutron capture therapy (BNCT) has been significantly hindered by the slow development of boron drug-targeting methodologies for the selective delivery of high boron concentration sto malignant cells. We have successfully sought to fill this need by creating liposomes suitable as in vivo boron delivery vehicles for BNCT. Delivery of therapeutic quantities of boron to tumors in murine models has been achieved with small unilamellar boron-rich liposomes. Subsequently, attempts have been made to improve delivery efficiency of liposomes encapsulating boron-containing water-soluble species into their hollow core by incorporating lipophilic boron compounds as addenda to the liposome bilayer, incorporating boron compounds as structural components of the bilayer (which however, poses the risk of sacrificing some stability), and combinations thereof. Regardless of the method, approximately 90% of the total liposome mass remains therapeutically inactive and comprised of the vehicle's construction materials, while less than 5% is boron for neutron targeting. Following this laboratory's intensive study, the observed tumor specificity of certain liposomes has been attributed to their diminutive size of these liposomes (30-150 nm), which enables these small vesicles to pass through the porous, immature vasculature of rapidly growing tumor tissue. We surmised that any amphiphilic nanoparticle of suitable size could possess some tumor selectivity. Consequently, the discovery of a very boron-rich nanoparticle delivery agent with biodistribution performance similar to unilamellar liposomes became one of our goals. Closomers, a new class of polyhedral borane derivatives, attracted us as an alternative BNCT drug-delivery system. We specifically envisioned dodeca (nido-carboranyl)-substituted closomers as possibly having a great potential role in BNCT drug delivery. They could function as extraordinarily boron-rich BNCT drugs since they are amphiphilic

Neutron capture experiments with 4π DANCE Calorimeter

Directory of Open Access Journals (Sweden)

Krtička M.

2012-02-01

Full Text Available In recent years we have performed a series of neutron capture experiments with the DANCE detector array located at the Los Alamos Neutron Science Center. The radiative decay spectrum from the compound nucleus contains important information about nuclear structure and the reaction mechanism. The primary goals of the measurements are to obtain improved capture cross sections, to determine properties of the photon strength function, to improve neutron level densities and strength functions by determining the spin and parity of the capturing states. We shall present examples of our recent results.

Hydrophilic interaction chromatography coupled matrix assisted laser desorption/ionization mass spectrometry for molecular analysis of organic compounds in medicines, tea, and coffee

KAUST Repository

Wang, Renqi

2013-01-01

Natural occurring organic compounds from food, natural organic matter, as well as metabolic products have received intense attention in current chemical and biological studies. Examination of unknown compounds in complex sample matrices is hampered by the limited choices for data readout and molecular elucidation. Herein, we report a generic method of hydrophilic interaction chromatography (HILIC) coupled with matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the rapid characterization of ingredients in pharmaceutical compounds, tea, and coffee. The analytes were first fractionated using a cationic HILIC column prior to MALDI-MS analyses. It was found that the retention times of a compound arising from different samples were consistent under the same conditions. Accordingly, molecules can be readily characterized by both the mass and chromatographic retention time. The retention behaviors of acidic and basic compounds on the cationic HILIC column were found to be significantly influenced by the pH of mobile phases, whereas neutral compounds depicted a constant retention time at different pH. The general HILIC-MALDI-MS method is feasible for fast screening of naturally occurring organic compounds. A series of homologs can be determined if they have the same retention behavior. Their structural features can be elucidated by considering their mass differences and hydrophilic properties as determined by HILIC chromatogram. © 2013 The Royal Society of Chemistry.

The origin of the Crab Nebula and the electron capture supernova in 8-10 M solar mass stars

Science.gov (United States)

Nomoto, K.

1981-01-01

The chemical composition of the Crab Nebula is compared with several presupernova models. The small carbon and oxygen abundances in the helium-rich nebula are consistent with only the presupernova model of the star whose main sequence mass was MMS approximately 8-9.5 M. More massive stars contain too much carbon in the helium layer and smaller mass stars do not leave neutron stars. The progenitor star of the Crab Nebula lost appreciable part of the hydrogen-rich envelope before the hydrogen-rich and helium layers were mixed by convection. Finally it exploded as the electron capture supernova; the O+Ne+Mg core collapsed to form a neutron star and only the extended helium-rich envelope was ejected by the weak shock wave.

Optimization and application of atmospheric pressure chemical and photoionization hydrogen-deuterium exchange mass spectrometry for speciation of oxygen-containing compounds.

Science.gov (United States)

Acter, Thamina; Kim, Donghwi; Ahmed, Arif; Jin, Jang Mi; Yim, Un Hyuk; Shim, Won Joon; Kim, Young Hwan; Kim, Sunghwan

2016-05-01

This paper presents a detailed investigation of the feasibility of optimized positive and negative atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and atmospheric pressure photoionization (APPI) MS coupled to hydrogen-deuterium exchange (HDX) for structural assignment of diverse oxygen-containing compounds. The important parameters for optimization of HDX MS were characterized. The optimized techniques employed in the positive and negative modes showed satisfactory HDX product ions for the model compounds when dichloromethane and toluene were employed as a co-solvent in APCI- and APPI-HDX, respectively. The evaluation of the mass spectra obtained from 38 oxygen-containing compounds demonstrated that the extent of the HDX of the ions was structure-dependent. The combination of information provided by different ionization techniques could be used for better speciation of oxygen-containing compounds. For example, (+) APPI-HDX is sensitive to compounds with alcohol, ketone, or aldehyde substituents, while (-) APPI-HDX is sensitive to compounds with carboxylic functional groups. In addition, the compounds with alcohol can be distinguished from other compounds by the presence of exchanged peaks. The combined information was applied to study chemical compositions of degraded oils. The HDX pattern, double bond equivalent (DBE) distribution, and previously reported oxidation products were combined to predict structures of the compounds produced from oxidation of oil. Overall, this study shows that APCI- and APPI-HDX MS are useful experimental techniques that can be applied for the structural analysis of oxygen-containing compounds.

{sup 1}H and {sup 10}B NMR and MRI investigation of boron- and gadolinium-boron compounds in boron neutron capture therapy

Energy Technology Data Exchange (ETDEWEB)

Bonora, M., E-mail: marco.bonora@unipv.it [Physics Department ' A. Volta' , University of Pavia, Via Bassi 6, 27100 Pavia (Italy)] [CNISM Unit (Italy); Corti, M.; Borsa, F. [Physics Department ' A. Volta' , University of Pavia, Via Bassi 6, 27100 Pavia (Italy)] [CNISM Unit (Italy); Bortolussi, S.; Protti, N.; Santoro, D.; Stella, S.; Altieri, S. [Nuclear and Theoretical Physics Department, University of Pavia, Via Bassi 6, 27100 Pavia (Italy)] [INFN Pavia (Italy); Zonta, C.; Clerici, A.M.; Cansolino, L.; Ferrari, C.; Dionigi, P. [Surgical Sciences Department, Experimental Surgery Laboratory, University of Pavia, Pavia (Italy); Porta, A.; Zanoni, G.; Vidari, G. [Organic Chemistry Department, University of Pavia, Via Taramelli 10, 27100 Pavia (Italy)

2011-12-15

{sup 10}B molecular compounds suitable for Boron Neutron Capture Therapy (BNCT) are tagged with a Gd(III) paramagnetic ion. The newly synthesized molecule, Gd-BPA, is investigated as contrast agent in Magnetic Resonance Imaging (MRI) with the final aim of mapping the boron distribution in tissues. Preliminary Nuclear Magnetic Resonance (NMR) measurements, which include {sup 1}H and {sup 10}B relaxometry in animal tissues, proton relaxivity of the paramagnetic Gd-BPA molecule in water and its absorption in tumoral living cells, are reported.

Analysis of air-, moisture- and solvent-sensitive chemical compounds by mass spectrometry using an inert atmospheric pressure solids analysis probe.

Science.gov (United States)

Mosely, Jackie A; Stokes, Peter; Parker, David; Dyer, Philip W; Messinis, Antonis M

2018-02-01

A novel method has been developed that enables chemical compounds to be transferred from an inert atmosphere glove box and into the atmospheric pressure ion source of a mass spectrometer whilst retaining a controlled chemical environment. This innovative method is simple and cheap to implement on some commercially available mass spectrometers. We have termed this approach inert atmospheric pressure solids analysis probe ( iASAP) and demonstrate the benefit of this methodology for two air-/moisture-sensitive chemical compounds whose characterisation by mass spectrometry is now possible and easily achieved. The simplicity of the design means that moving between iASAP and standard ASAP is straightforward and quick, providing a highly flexible platform with rapid sample turnaround.

THE DEVELOPMENT OF IODINE BASED IMPINGER SOLUTIONS FOR THE EFFICIENT CAPTURE OF HG USING DIRECT INJECTION NEBULIZATION - INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY ANALYSIS

Science.gov (United States)

Inductively coupled plasma mass spectrometry (ICP/MS) with direct injection nebulization (DIN) was used to evaluate novel impinger solution compositions capable of capturing elemental mercury (Hgo) in EPA Method 5 type sampling. An iodine based impinger solutoin proved to be ver...

Dissolved organic carbon enhances the mass transfer of hydrophobic organic compounds from Nonaqueous Phase Liquids (NAPLs) into the aqueous phase

NARCIS (Netherlands)

Smith, K.E.C.; Thullner, M.; Wick, L.Y.; Harms, H.

2011-01-01

The hypothesis that dissolved organic carbon (DOC) enhances the mass transfer of hydrophobic organic compounds from nonaqueous phase liquids (NAPLs) into the aqueous phase above that attributable to dissolved molecular diffusion alone was tested. In controlled experiments, mass transfer rates of

Evaluation by mass fragmentography of metabolic pathways of endogenous and exogenous compounds in eukaryote cell cultures

International Nuclear Information System (INIS)

Padieu, P.; Maume, B.F.

1977-01-01

Carbon-14 labelled compounds in cell cultures are used to establish the interconnections between different metabolic pathways as well as the competitive action of effectors on these different pathways. Analysis was performed by the GC-MS combination. Identification was carried out by comparison with the mass spectra of d9-TMS, 35 Cl-TMS and 37 Cl-TMS derivatizations of the culture extracts. Examples are given of the metabolic study of hormonal steroids and of safrale, a carcinogenic compound, by differentiated eukaryotic cells in cultures from the rat

Proton transfer reaction-mass spectrometry volatile organic compound fingerprinting for monovarietal extra virgin olive oil identification

NARCIS (Netherlands)

Ruiz-Samblas, C.; Tres, A.; Koot, A.H.; Ruth, van S.M.; Gonzalez-Casado, A.; Cuadros-Rodriguez, L.

2012-01-01

Proton transfer reaction-mass spectrometry (PTR-MS) is a relatively new technique that allows the fast and accurate qualification of the volatile organic compound (VOC) fingerprint. This paper describes the analysis of thirty samples of extra virgin olive oil, of five different varieties of olive

Determination of some volatile compounds in alcoholic beverage by headspace solid-phase microextraction gas chromatography - mass spectrometry

Science.gov (United States)

Schmutzer, G.; Avram, V.; Feher, I.; David, L.; Moldovan, Z.

2012-02-01

The volatile composition of alcoholic beverage was studied by headspace solid-phase microextraction (HSSPME) method and gas chromatography - mass spectrometry (GC-MS). Some volatile compounds, such as alcohols, esters, terpenes and other are mainly responsible for the flavor of fortified wines and their amounts specify the quality of the alcoholic beverages. From this perspective it is interesting to develop a rapid, selective and sensitive analytical method suitable for simultaneous quantification of the main molecules being responsible for the organoleptic characteristic of alcoholic beverages. Vermouth fortified drink was analyzed in order to characterize the volatile profile. Using the HS-SPME/GC-MS a number of twenty-six volatile compounds from a commercial market alcoholic beverage were identified. The most abundant compounds were m-thymol, o-thymol and eugenol, alongside of the ethyl ester compounds.

Laser capture microdissection: Arcturus(XT) infrared capture and UV cutting methods.

Science.gov (United States)

Gallagher, Rosa I; Blakely, Steven R; Liotta, Lance A; Espina, Virginia

2012-01-01

Laser capture microdissection (LCM) is a technique that allows the precise procurement of enriched cell populations from a heterogeneous tissue under direct microscopic visualization. LCM can be used to harvest the cells of interest directly or can be used to isolate specific cells by ablating the unwanted cells, resulting in histologically enriched cell populations. The fundamental components of laser microdissection technology are (a) visualization of the cells of interest via microscopy, (b) transfer of laser energy to a thermolabile polymer with either the formation of a polymer-cell composite (capture method) or transfer of laser energy via an ultraviolet laser to photovolatize a region of tissue (cutting method), and (c) removal of cells of interest from the heterogeneous tissue section. Laser energy supplied by LCM instruments can be infrared (810 nm) or ultraviolet (355 nm). Infrared lasers melt thermolabile polymers for cell capture, whereas ultraviolet lasers ablate cells for either removal of unwanted cells or excision of a defined area of cells. LCM technology is applicable to an array of applications including mass spectrometry, DNA genotyping and loss-of-heterozygosity analysis, RNA transcript profiling, cDNA library generation, proteomics discovery, and signal kinase pathway profiling. This chapter describes the unique features of the Arcturus(XT) laser capture microdissection instrument, which incorporates both infrared capture and ultraviolet cutting technology in one instrument, using a proteomic downstream assay as a model.

Upscaling of enzyme enhanced CO2 capture

DEFF Research Database (Denmark)

Gladis, Arne Berthold

Fossil fuels are the backbone of the energy generation in the coming decades for USA, China, India and Europe, hence high greenhouse gas emissions are expected in future. Carbon capture and storage technology (CCS) is the only technology that can mitigate greenhouse gas emissions from fossil fuel...... the mass transfer of CO2 with slow-capturing but energetically favorable solvents can open up a variety of new process options for this technology. The ubiquitous enzyme carbonic anhydrase (CA), which enhances the mass transfer of CO2 in the lungs by catalyzing the reversible hydration of CO2, is one very...... enhanced CO2 capture technology by identifying the potentials and limitations in lab and in pilot scale and benchmarking the process against proven technologies. The main goal was to derive a realistic process model for technical size absorbers with a wide range of validity incorporating a mechanistic...

Characterization and extraction of volatile compounds from pineapple (Ananas comosus L. Merril processing residues

Directory of Open Access Journals (Sweden)

Lília Calheiros de Oliveira Barretto

2013-12-01

Full Text Available The aim of this study was to extract and identify volatile compounds from pineapple residues generated during concentrated juice processing. Distillates of pineapple residues were obtained using the following techniques: simple hydrodistillation and hydrodistillation by passing nitrogen gas. The volatile compounds present in the distillates were captured by the solid-phase microextraction technique. The volatile compounds were identified in a system of high resolution gas chromatography system coupled with mass spectrometry using a polyethylene glycol polar capillary column as stationary phase. The pineapple residues constituted mostly of esters (35%, followed by ketones (26%, alcohols (18%, aldehydes (9%, acids (3% and other compounds (9%. Odor-active volatile compounds were mainly identified in the distillate obtained using hydrodistillation by passing nitrogen gas, namely decanal, ethyl octanoate, acetic acid, 1-hexanol, and ketones such as γ-hexalactone, γ-octalactone, δ-octalactone, γ-decalactone, and γ-dodecalactone. This suggests that the use of an inert gas and lower temperatures helped maintain higher amounts of flavor compounds. These data indicate that pineapple processing residue contained important volatile compounds which can be extracted and used as aroma enhancing products and have high potential for the production of value-added natural essences.

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

Science.gov (United States)

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

2017-12-01

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

Lichen specific thallus mass and secondary compounds change across a retrogressive fire-driven chronosequence.

Science.gov (United States)

Asplund, Johan; Sandling, Aron; Wardle, David A

2012-01-01

In the long-term absence of major disturbances ecosystems enter a state of retrogression, which involves declining soil fertility and consequently a reduction in decomposition rates. Recent studies have looked at how plant traits such as specific leaf mass and amounts of secondary compounds respond to declining soil fertility during retrogression, but there are no comparable studies for lichen traits despite increasing recognition of the role that lichens can play in ecosystem processes. We studied a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. We used this system to explore how specific thallus mass (STM) and carbon based secondary compounds (CBSCs) change in three common epiphytic lichen species (Hypogymnia phsyodes, Melanohalea olivacea and Parmelia sulcata) as soil fertility declines during this retrogression. We found that STMs of lichens increased sharply during retrogression, and for all species soil N to P ratio (which increased during retrogression) was a strong predictor of STM. When expressed per unit area, medullary CBSCs in all species and cortical CBSCs in P. sulcata increased during retrogression. Meanwhile, when expressed per unit mass, only cortical CBSCs in H. physodes responded to retrogression, and in the opposite direction. Given that lichen functional traits are likely to be important in driving ecological processes that drive nutrient and carbon cycling in the way that plant functional traits are, the changes that they undergo during retrogression could potentially be significant for the functioning of the ecosystem.

Capture cross sections for very heavy systems

International Nuclear Information System (INIS)

Rowley, N.; Grar, N.; Ntshangase, S.S.

2006-01-01

In intermediate-mass systems, collective excitations of the target and projectile can greatly enhance the sub-barrier capture cross section σ cap by giving rise to a distribution of Coulomb barriers. For such systems, capture essentially leads directly to fusion (formation of a compound nucleus (CN)), which then decays through the emission of light particles (neutrons, protons, and alpha particles). Thus the evaporation-residue (ER) cross section is essentially equal to σ cap . For heavier systems the experimental situation is significantly more complicated due to the presence of quasifission (QF) (rapid separation into two fragments before the CN is formed) and by fusion-fission (FF) of the CN itself. Thus three cross sections need to be measured in order to evaluate σ cap . Although the ER essentially recoil along the beam direction. QF and FF fragments are scattered to all angles and require the measurement of angular distribution in order to obtain the excitation function and barrier distribution for capture. Two other approaches to this problem exist. If QF is not important, one can still measure just the ER cross section and try to reconstruct the corresponding σ cap through use of an evaporation-model code that takes account of the FF degree of freedom. Some earlier results on σ cap obtained in this way will be re-analyzed with detail coupled-channels calculations, and the extra-push phenomenon discussed. One may also try to obtain σ cap by exploiting unitarity, that is, by measuring instead the flux of particles corresponding to quasielastic (QE) scattering from the Coulomb barrier. Some new QE results obtained for the 86 Kr + 208 Pb system at iThemba LABS in South Africa will be presented [ru

Analytical method for biomonitoring of endocrine-disrupting compounds (bisphenol A, parabens, perfluoroalkyl compounds and a brominated flame retardant) in human hair by liquid chromatography-tandem mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Martín, Julia; Santos, Juan Luis; Aparicio, Irene, E-mail: iaparicio@us.es; Alonso, Esteban

2016-11-16

In this paper, a method for the determination of four groups of endocrine-disrupting compounds in human hair is proposed. Target compounds were a plastic monomer (bisphenol A), three parabens commonly used as preservatives (methylparaben, ethylparaben and propylparaben), six perfluoroalkyl compounds commonly used as water, oil and dirt repellents (perfluorooctane sulfonic acid and five perfluoroalkyl carboxylic acids, with alkyl chains from four to eight carbon atoms) and a brominated flame retardant (hexabromocyclododecane). All of them are of especial concern to human health because they are utilized in many everyday products. The method is based on hair incubation with methanol/acetic acid solution (85:15, v/v), extraction with acetone for 15 min in an ultrasonic bath and analysis by liquid chromatography-electrospray-tandem mass spectrometry in negative ionization mode. Limits of quantification in hair samples ranged from 0.6 ng g{sup −1} to 6.1 ng g{sup −1}, except for hexabromocyclododecane (36 ng g{sup −1}). Recoveries were higher than 69%. Intra-day and inter-day precision, expressed as relative standard deviation, were lower than 15% and 10%, respectively. The applicability of the method was proven by analyzing the target compounds in hair samples from six volunteers. High frequencies of detection and concentrations were obtained for bisphenol A (83% of samples; concentrations up to 158 ng g{sup −1}) and parabens (100% of samples; concentrations up to 624 ng g{sup −1}). Lower concentrations were detected for the perfluoroalkyl compounds (up to 13 ng g{sup −1}). Hexabromocyclododecane was not detected. - Highlights: • Method for biomonitoring of endocrine-disrupting compounds in human hair. • Target compounds are commonly present in everyday products. • Method based on hair digestion and liquid chromatography-tandem mass spectrometry. • Good sensitivity, recoveries and precision and low matrix effect were obtained. �

Analytical method for biomonitoring of endocrine-disrupting compounds (bisphenol A, parabens, perfluoroalkyl compounds and a brominated flame retardant) in human hair by liquid chromatography-tandem mass spectrometry

International Nuclear Information System (INIS)

Martín, Julia; Santos, Juan Luis; Aparicio, Irene; Alonso, Esteban

2016-01-01

In this paper, a method for the determination of four groups of endocrine-disrupting compounds in human hair is proposed. Target compounds were a plastic monomer (bisphenol A), three parabens commonly used as preservatives (methylparaben, ethylparaben and propylparaben), six perfluoroalkyl compounds commonly used as water, oil and dirt repellents (perfluorooctane sulfonic acid and five perfluoroalkyl carboxylic acids, with alkyl chains from four to eight carbon atoms) and a brominated flame retardant (hexabromocyclododecane). All of them are of especial concern to human health because they are utilized in many everyday products. The method is based on hair incubation with methanol/acetic acid solution (85:15, v/v), extraction with acetone for 15 min in an ultrasonic bath and analysis by liquid chromatography-electrospray-tandem mass spectrometry in negative ionization mode. Limits of quantification in hair samples ranged from 0.6 ng g"−"1 to 6.1 ng g"−"1, except for hexabromocyclododecane (36 ng g"−"1). Recoveries were higher than 69%. Intra-day and inter-day precision, expressed as relative standard deviation, were lower than 15% and 10%, respectively. The applicability of the method was proven by analyzing the target compounds in hair samples from six volunteers. High frequencies of detection and concentrations were obtained for bisphenol A (83% of samples; concentrations up to 158 ng g"−"1) and parabens (100% of samples; concentrations up to 624 ng g"−"1). Lower concentrations were detected for the perfluoroalkyl compounds (up to 13 ng g"−"1). Hexabromocyclododecane was not detected. - Highlights: • Method for biomonitoring of endocrine-disrupting compounds in human hair. • Target compounds are commonly present in everyday products. • Method based on hair digestion and liquid chromatography-tandem mass spectrometry. • Good sensitivity, recoveries and precision and low matrix effect were obtained. • Method was successfully

Gas permeation process for post combustion CO2 capture

International Nuclear Information System (INIS)

Pfister, Marc

2017-01-01

CO 2 Capture and Storage (CCS) is a promising solution to separate CO 2 from flue gas, to reduce the CO 2 emissions in the atmosphere, and hence to reduce global warming. In CCS, one important constraint is the high additional energy requirement of the different capture processes. That statement is partly explained by the low CO 2 fraction in the inlet flue gas and the high output targets in terms of CO 2 capture and purity (≥90%). Gas permeation across dense membrane can be used in post combustion CO 2 capture. Gas permeation in a dense membrane is ruled by a mass transfer mechanism and separation performance in a dense membrane are characterized by component's effective permeability and selectivity. One of the newest and encouraging type of membrane in terms of separation performance is the facilitated transport membrane. Each particular type of membrane is defined by a specific mass transfer law. The most important difference to the mass transfer behavior in a dense membrane is related to the facilitated transport mechanism and the solution diffusion mechanism and its restrictions and limitations. Permeation flux modelling across a dense membrane is required to perform a post combustion CO 2 capture process simulation. A CO 2 gas permeation separation process is composed of a two-steps membrane process, one drying step and a compression unit. Simulation on the energy requirement and surface area of the different membrane modules in the global system are useful to determine the benefits of using dense membranes in a post combustion CO 2 capture technology. (author)

Gadolinium atom on neutron capture therapy

International Nuclear Information System (INIS)

Oda, Y.; Takagaki, M.; Miyatake, S.; Kikuchi, H.

1994-01-01

This report describes our measurements of gadolinium concentrations in several brain tumors obtained from fresh surgical specimens, as compared with corresponding concentrations in the blood. Moreover we tried to find out if the gadolinium concentration is high enough to use this compound in the treatment of brain tumors by neutron capture therapy. (J.P.N.)

Application of the boron neutron capture therapy to undifferentiated thyroid cancer using two boron compounds (BPA and BOPP)

International Nuclear Information System (INIS)

Viaggi, Mabel; Dagrosa, Maria A.; Juvenal, Guillermo J.; Pisarev, Mario A.; Longhino, Juan M.; Blaumann, Hernan R.; Calzetta Larrieu, Osvaldo A.; Kahl, Stephen B.

2004-01-01

We have shown the selective uptake of boronophenylalanine (BPA) by undifferentiated thyroid cancer (UTC) human cell line ARO, both in vitro and in vivo. Moreover, a 50% histologic cure of mice bearing the tumor was observed when the complete boron neutron capture therapy was applied. More recently we have analyzed the biodistribution of BOPP (tetrakis-carborane carboxylate ester of 2,4-bis-(ba-dihydroxyethyl)-deutero-porphyrin IX) and showed that when BOPP was injected 5 days before BPA, and the animals were sacrificed 60 min after the ip injection of BPA, a significant increase in boron uptake by the tumor was found (38-45ppm with both compounds Vs. 20 ppm with BPA alone). Five days post the ip BOPP injection and 1 hr after BPA, the ratios were: tumor/blood 3,75; tumor /distal skin 2. Other important ratios were tumor/thyroid 6,65 and tumor/lung 3,8. The present studies were performed in mice transplanted with ARO cells and injected with BOPP and BPA. Only in mice treated with the neutron beam and injected with the boronated compounds we observed a 100% control of tumor growth. Two groups of mice received different total absorbed doses: 3.00 and 6.01 Gy, but no further improvement in the outcome was found compared to the previous results using BPA alone (4.3 Gy). (author)

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.

Classification of wine by determination of bioactive phenolic compounds using high resolution mass spectrometry

OpenAIRE

Ivanova, Violeta; Dimovska, Violeta; Mitrev, Sasa; Gulaboski, Rubin; Bogeva, Elena; Petruseva, Dragana; Causon, Tim; Hann, Stephan

2016-01-01

In this project proposal, metabolomic fingerprinting of wine samples will be examined using high performance liquid chromatography combined with ion mobility quadruple time-of-flight mass spectrometry (HPLC–IMS-QTOF-MS) for the first time. Bioactive compounds in wines from various red and white varieties produced in Macedonia and Austria from different wine regions and different vintages will be determined for the first time using a non-targeted fingerprinting approach on this analytical plat...

Targeted metabolite profile of food bioactive compounds by Orbitrap high resolution mass spectrometry: The 'FancyTiles' approach

NARCIS (Netherlands)

Troise, A.D.; Ferracane, R.; Palermo, M.; Fogliano, V.

2014-01-01

In this paper a new targeted metabolic profile approach using Orbitrap high resolution mass spectrometry was described. For each foodmatrix various classes of bioactive compounds and some specificmetabolites of interest were selected on the basis of the existing knowledge creating an easy-to-read

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

Science.gov (United States)

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

2009-06-01

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

Hypernetworks Reveal Compound Variables That Capture Cooperative and Competitive Interactions in a Soccer Match.

Science.gov (United States)

Ramos, João; Lopes, Rui J; Marques, Pedro; Araújo, Duarte

2017-01-01

transformations near the goal depends on significant changes in the players' speed and direction; (iii) at macro level, simplices are connected to one another, forming "simplices of simplices" including the goalkeeper and the goal. These results validate qualitatively that hypernetworks and related compound variables can capture and be used in the analysis of the cooperative and competitive interactions between players and sets of players in soccer matches.

Hypernetworks Reveal Compound Variables That Capture Cooperative and Competitive Interactions in a Soccer Match

Directory of Open Access Journals (Sweden)

João Ramos

2017-08-01

transformations near the goal depends on significant changes in the players' speed and direction; (iii at macro level, simplices are connected to one another, forming “simplices of simplices” including the goalkeeper and the goal. These results validate qualitatively that hypernetworks and related compound variables can capture and be used in the analysis of the cooperative and competitive interactions between players and sets of players in soccer matches.

Capture of Planetesimals into a Circumterrestrial Swarm

Science.gov (United States)

Weidenschilling, S. J.

1985-01-01

The lunar origin model considered in this report involves processing of protolunar material through a circumterrestrial swarm of particles. Once such a swarm has formed, it can gain mass by capturing infalling planetesimals and ejecta from giant impacts on the Earth, although the angular momentum supply from these sources remains a problem. The first stage of formation of a geocentric swarm by capture of planetesimals from initially heliocentric orbits is examined. The only plausible capture mechanism that is not dependent on very low approach velocities is the mutual collision of planetesimals passing within Earth's sphere of influence. The dissipation of energy in inelastic collisions or accretion events changes the value of the Jacobi parameter, allowing capture into bound geocentric orbits. This capture scenario was tested directly by many body numerical integration of planetesimal orbits in near Earth space.

Volatile organic compound analysis in wood combustion and meat cooking emissions

International Nuclear Information System (INIS)

Zielinska, B.; McDonald, J.

1999-01-01

Residential wood combustion and meat cooking emissions were each analyzed for volatile organic compounds (VOC). Emissions were diluted 60--100 times, cooled to ambient temperature, and allowed 80 seconds for condensation prior to collection with the aid of a DRI-constructed dilution stack sampler. Fireplace and wood-stove emissions testing was conducted at the DRI facilities. Wood type, wood moisture, burn rate, and fuel load were varied for different experiments. Meat emissions testing was conducted at the CE-CERT stationary emissions lab, University of California, Riverside. Meat type, fat content, and cooking appliance were changed in different tests. VOCs were collected using stainless-steel 6 L canisters and Tenax cartridges, whereas for carbonyl compound collection 2,4-dinitrophenylhydrazine (DNPH)-impregnated C 18 SepPack cartridges were used. Analysis of VOC collected with canisters and Tenax cartridges was conducted by Gas Chromatography/Mass Spectrometry (GC/MS) and by GC/FID/ECD (flame ionization detection/electron capture detection). DNPH-impregnated cartridges were analyzed for fourteen C 1 --C 7 carbonyl compounds, using the HPLC method. The results of these measurements are discussed

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.

Identification of new natural sweet compounds in wine using centrifugal partition chromatography-gustatometry and Fourier transform mass spectrometry.

Science.gov (United States)

Marchal, Axel; Waffo-Téguo, Pierre; Génin, Eric; Mérillon, Jean-Michel; Dubourdieu, Denis

2011-12-15

Sweetness contributes notably to the taste-balance of dry wines and increases during oak-barrel aging owing to the release of natural sweeteners from wood. The search for such taste-active molecules, which are sometimes present at very low concentrations in wine or other complex matrixes, requires both reliable purification tools and powerful identification techniques. Here, we report the development of an original inductive method using centrifugal partition chromatography (CPC) and sensorial analysis. This method, called CPC-gustatometry, was implemented to isolate a sweet fraction with only four compounds from a complex oak wood extract. The recently developed Fourier transform mass spectrometry (FT-MS, Orbitrap analyzer) was used jointly with two-dimensional nuclear magnetic resonance (2D (1)H and (13)C NMR) to obtain the structural elucidation of the purified compounds. The tandem mass spectrometry (MS/MS) spectra obtained with resonant and nonresonant fragmentation modes were compared, thus providing complementary information about the molecular structure. Two oleanane-type triterpenoids substituted with galloyl and glucosyl moieties were identified, one of which exhibits sweet properties. We term these compounds which have never been reported, Quercotriterpenoside I and II.

Recent advances in neutron capture therapy (NCT)

International Nuclear Information System (INIS)

Fairchild, R.G.

1985-01-01

The application of the 10 B(n,α) 7 Li reaction to cancer radiotherapy (Neutron Capture therapy, or NCT) has intrigued investigators since the discovery of the neutron. This paper briefly summarizes data describing recently developed boronated compounds with evident tumor specificity and extended biological half-lives. The implication of these compounds to NCT is evaluated in terms of Therapeutic Gain (TG). The optimization of NCT using band-pass filtered beams is described, again in terms of TG, and irradiation times with these less intense beams are estimated. 24 refs., 3 figs., 3 tabs

Boron containing compounds and their preparation and use in neutron capture therapy

Energy Technology Data Exchange (ETDEWEB)

Gabel, D.

1992-09-01

The present invention pertains to boron containing thiouracil derivatives, their method of preparations, and their use in the therapy of malignant melanoma using boron neutron capture therapy. No Drawings

A review of electron-capture and electron-transfer dissociation tandem mass spectrometry in polymer chemistry

International Nuclear Information System (INIS)

Hart-Smith, Gene

2014-01-01

Graphical abstract: -- Highlights: •ECD and ETD can produce unique and diagnostically useful polymer ion fragmentation data. •The operating principles of ECD and ETD are discussed in relation to other dissociation techniques. •Key characteristics of ECD and ETD spectra, as observed from biological analytes, are discussed. •ECD and ETD analyses are compared to CID analyses for different classes of synthetic polymer. -- Abstract: Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community

Direct analysis of volatile organic compounds in foods by headspace extraction atmospheric pressure chemical ionisation mass spectrometry.

Science.gov (United States)

Perez-Hurtado, P; Palmer, E; Owen, T; Aldcroft, C; Allen, M H; Jones, J; Creaser, C S; Lindley, M R; Turner, M A; Reynolds, J C

2017-11-30

The rapid screening of volatile organic compounds (VOCs) by direct analysis has potential applications in the areas of food and flavour science. Currently, the technique of choice for VOC analysis is gas chromatography/mass spectrometry (GC/MS). However, the long chromatographic run times and elaborate sample preparation associated with this technique have led a movement towards direct analysis techniques, such as selected ion flow tube mass spectrometry (SIFT-MS), proton transfer reaction mass spectrometry (PTR-MS) and electronic noses. The work presented here describes the design and construction of a Venturi jet-pump-based modification for a compact mass spectrometer which enables the direct introduction of volatiles for qualitative and quantitative analysis. Volatile organic compounds were extracted from the headspace of heated vials into the atmospheric pressure chemical ionization source of a quadrupole mass spectrometer using a Venturi pump. Samples were analysed directly with no prior sample preparation. Principal component analysis (PCA) was used to differentiate between different classes of samples. The interface is shown to be able to routinely detect problem analytes such as fatty acids and biogenic amines without the requirement of a derivatisation step, and is shown to be able to discriminate between four different varieties of cheese with good intra and inter-day reproducibility using an unsupervised PCA model. Quantitative analysis is demonstrated using indole standards with limits of detection and quantification of 0.395 μg/mL and 1.316 μg/mL, respectively. The described methodology can routinely detect highly reactive analytes such as volatile fatty acids and diamines without the need for a derivatisation step or lengthy chromatographic separations. The capability of the system was demonstrated by discriminating between different varieties of cheese and monitoring the spoilage of meats. © 2017 The Authors. Rapid Communications in Mass

PhosProtect - a novel and superior compound to tag and protect phospho-groups during mass spectrometry based phospho-proteomics

DEFF Research Database (Denmark)

2012-01-01

Value Proposition The PhosProtect compound alone (developed and tested, IP secured)* • protects phospho-groups during tandem mass spectrometry, thus reducing problematic neutral loss of phosphate. • provides unique phospho-tag by causing isotopic distribution patterns in MS and MS/MS data. The PhosProtect...... compound covalently bound to column material (in progress , IP secured)** • Combines enrichment, protection and tagging of phospho-peptides and phospho-lipids in one easy workflow....

Mass Spectrometry Imaging of low Molecular Weight Compounds in Garlic (Allium sativum L.) with Gold Nanoparticle Enhanced Target.

Science.gov (United States)

Misiorek, Maria; Sekuła, Justyna; Ruman, Tomasz

2017-11-01

Garlic (Allium sativum) is the subject of many studies due to its numerous beneficial properties. Although compounds of garlic have been studied by various analytical methods, their tissue distributions are still unclear. Mass spectrometry imaging (MSI) appears to be a very powerful tool for the identification of the localisation of compounds within a garlic clove. Visualisation of the spatial distribution of garlic low-molecular weight compounds with nanoparticle-based MSI. Compounds occurring on the cross-section of sprouted garlic has been transferred to gold-nanoparticle enhanced target (AuNPET) by imprinting. The imprint was then subjected to MSI analysis. The results suggest that low molecular weight compounds, such as amino acids, dipeptides, fatty acids, organosulphur and organoselenium compounds are distributed within the garlic clove in a characteristic manner. It can be connected with their biological functions and metabolic properties in the plant. New methodology for the visualisation of low molecular weight compounds allowed a correlation to be made between their spatial distribution within a sprouted garlic clove and their biological function. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Application of Atmospheric Pressure Photoionization H/D-exchange Mass Spectrometry for Speciation of Sulfur-containing Compounds.

Science.gov (United States)

Acter, Thamina; Kim, Donghwi; Ahmed, Arif; Ha, Ji-Hyoung; Kim, Sunghwan

2017-08-01

Herein we report the observation of atmospheric pressure in-source hydrogen-deuterium exchange (HDX) of thiol group for the first time. The HDX for thiol group was optimized for positive atmospheric pressure photoionization (APPI) mass spectrometry (MS). The optimized HDX-MS was applied for 31 model compounds (thiols, thiophenes, and sulfides) to demonstrate that exchanged peaks were observed only for thiols. The optimized method has been successfully applied to the isolated fractions of sulfur-rich oil samples. The exchange of one and two thiol hydrogens with deuterium was observed in the thiol fraction; no HDX was observed in the other fractions. Thus, the results presented in this study demonstrate that the HDX-MS method using APPI ionization source can be effective for speciation of sulfur compounds. This method has the potential to be used to access corrosion problems caused by thiol-containing compounds. Graphical Abstract ᅟ.

Determination of drugs and drug-like compounds in different samples with direct analysis in real time mass spectrometry.

Science.gov (United States)

Chernetsova, Elena S; Morlock, Gertrud E

2011-01-01

Direct analysis in real time (DART), a relatively new ionization source for mass spectrometry, ionizes small-molecule components from different kinds of samples without any sample preparation and chromatographic separation. The current paper reviews the published data available on the determination of drugs and drug-like compounds in different matrices with DART-MS, including identification and quantitation issues. Parameters that affect ionization efficiency and mass spectra composition are also discussed. Copyright © 2011 Wiley Periodicals, Inc.

Analysis of volatile organic compounds in pleural effusions by headspace solid-phase microextraction coupled with cryotrap gas chromatography and mass spectrometry.

Science.gov (United States)

Huang, Zhongping; Zhang, Jie; Zhang, Peipei; Wang, Hong; Pan, Zaifa; Wang, Lili

2016-07-01

Headspace solid-phase microextraction coupled with cryotrap gas chromatography and mass spectrometry was applied to the analysis of volatile organic compounds in pleural effusions. The highly volatile organic compounds were separated successfully with high sensitivity by the employment of a cryotrap device, with the construction of a cold column head by freezing a segment of metal capillary with liquid nitrogen. A total of 76 volatile organic compounds were identified in 50 pleural effusion samples (20 malignant effusions and 30 benign effusions). Among them, 34 more volatile organic compounds were detected with the retention time less than 8 min, by comparing with the normal headspace solid-phase microextraction coupled with gas chromatography and mass spectrometry method. Furthermore, 24 volatile organic compounds with high occurrence frequency in pleural effusion samples, 18 of which with the retention time less than 8 min, were selected for the comparative analysis. The results of average peak area comparison and box-plot analysis showed that except for cyclohexanone, 2-ethyl-1-hexanol, and tetramethylbenzene, which have been reported as potential cancer biomarkers, cyclohexanol, dichloromethane, ethyl acetate, n-heptane, ethylbenzene, and xylene also had differential expression between malignant and benign effusions. Therefore, the proposed approach was valuable for the comprehensive characterization of volatile organic compounds in pleural effusions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Processes involved in pion capture in hydrogen-containing molecules

International Nuclear Information System (INIS)

Horvath, D.

1983-03-01

A systematic analysis is presented of the possible elementary processes determining the fate of negative pions stopped in hydrogen-containing samples. Using a phenomenological description in comparison with the available experimental information on pion capture in hydrogen, it is shown that the formation and decay of pπ - atoms in compounds Zsub(m)Hsub(n) are determined mainly by the processes of Auger capture in a molecular orbit ZHπ - , transition from molecular to atomic orbit, transfer of pions to atoms Z in collisions pπ - +Z, and nuclear capture in collisions pπ - +H. The recent assumption of a considerable role of the processes of radiative atomic capture in bound hydrogen atoms, nuclear capture of pions by protons from the molecular state ZHπ - , or 'inner' transfer of the pion via tunnelling through the bond Z-H is not supported by the theory and contradicts the experimental data

Determination of naphthalene-derived compounds in apples by ultra-high performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Esparza, X; Moyano, E; Cosialls, J R; Galceran, M T

2013-06-11

Naphthylacetic acid, naphthyloxy acetic acid and naphthylacetamide belong to a group of synthetic substances known as "auxin-like" compounds which are used as growth regulators in vegetables and fruits due to their structure similarities with the indoleacetic acid, the most important plant auxin. This paper reports a selective, sensitive and fast ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of naphthylacetamide (NAD) and the isomers (α and β) of naphthylacetic acid (NAA) and naphthyloxy acetic (NOA) acid in apple samples. A baseline separation between the respective isomers was achieved using an RP-Amide column with gradient elution. The UHPLC-MS/MS method developed, using electrospray and selected reaction monitoring (SRM) acquisition mode led to a reliable determination of these family of compounds in apple samples at low quantitation levels, down to 1.0 μg kg(-1) and 0.25 μg kg(-1) respectively. For confirmation of NAA accurate mass measurement is proposed giving at these conditions quantitation limits of 10 μg kg(-1) for this compound. The UHPLC-MS/MS method developed was used for the analysis of apple samples harvested in three different apple fields from Lleida (Spain) during the blooming period. NAD and NAA were found in samples collected during 4-5 weeks after application at concentrations between the quantification limits and 43 μg kg(-1) and 24 μg kg(-1), respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

Measurement of volatile plant compounds in field ambient air by thermal desorption-gas chromatography-mass spectrometry.

Science.gov (United States)

Cai, Xiao-Ming; Xu, Xiu-Xiu; Bian, Lei; Luo, Zong-Xiu; Chen, Zong-Mao

2015-12-01

Determination of volatile plant compounds in field ambient air is important to understand chemical communication between plants and insects and will aid the development of semiochemicals from plants for pest control. In this study, a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to measure ultra-trace levels of volatile plant compounds in field ambient air. The desorption parameters of TD, including sorbent tube material, tube desorption temperature, desorption time, and cold trap temperature, were selected and optimized. In GC-MS analysis, the selected ion monitoring mode was used for enhanced sensitivity and selectivity. This method was sufficiently sensitive to detect part-per-trillion levels of volatile plant compounds in field ambient air. Laboratory and field evaluation revealed that the method presented high precision and accuracy. Field studies indicated that the background odor of tea plantations contained some common volatile plant compounds, such as (Z)-3-hexenol, methyl salicylate, and (E)-ocimene, at concentrations ranging from 1 to 3400 ng m(-3). In addition, the background odor in summer was more abundant in quality and quantity than in autumn. Relative to previous methods, the TD-GC-MS method is more sensitive, permitting accurate qualitative and quantitative measurements of volatile plant compounds in field ambient air.

[Simultaneous determination of ten organotin compounds in polyvinyl chloride plastics using gas chromatography-mass spectrometry].

Science.gov (United States)

Li, Ying; Li, Bin; Liu, Li; Zhang, Chen; Wu, Jingwu; Liu, Zhihong; Li, Xintian

2009-01-01

A rapid and effective gas chromatography coupled with mass spectrometry method has been developed systematically and studied for the simultaneous determination of 10 organotin compounds, dibutyltin-dichloride (DBT), n-butyltin-trichloride (MBT), triethyltinchloride (TET), fentin-chloride (TPhT), chlorotributylstannane (TBT), tri-n-propyltinchloride (TPrT), diphenyltin-dichloride (DPhT), tetrabutyltin (TeBT), di-n-octyltin-dichloride (DOT), phenyltin trichloride (MPhT)), in polyvinyl chloride (PVC) plastics. The PVC sample was dissolved with tetrahydrofuran and the polymer in the sample was precipitated with methanol, and then the target compounds were derivatized with sodium tetraethylborate and extracted with hexane under ultrasonication. The qualitative and quantitative analysis were carried out by GC-MS and the total ion chromatogram and selected ion chromatogram were obtained. The derivatization and extraction conditions, such as the derivatization time, derivatization pH value, dosages of derivatization reagent and precipitation reagent were optimized. The good linearities, recoveries and precisions were obtained. The linearity ranges were 0.5 - 50 mg/L. The linearity correlation coefficients of 10 organotin compounds were between 0.997 8 and 0.999 7. The average recoveries were 84.23% - 109.1% with relative standard deviations of 4.24% - 10.75%. The established method has been successfully applied to the determination of organotin compounds in PVC plastics.

Comparison of SPME Methods for Determining Volatile Compounds in Milk, Cheese, and Whey Powder

Directory of Open Access Journals (Sweden)

Michael H. Tunick

2013-11-01

Full Text Available Solid phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS are commonly used for qualitative and quantitative analysis of volatile compounds in various dairy products, but conditions have to be adjusted to maximize release while not generating new compounds that are absent in the original sample. Queso Fresco, a fresh non-melting cheese, may be heated at 60 °C for 30 min; in contrast, compounds are produced in milk when exposed to light and elevated temperatures, so milk samples are heated as little as possible. Products such as dehydrated whey protein are more stable and can be exposed to longer periods (60 min of warming at lower temperature (40 °C without decomposition, allowing for capture and analysis of many minor components. The techniques for determining the volatiles in dairy products by SPME and GC-MS have to be optimized to produce reliable results with minimal modifications and analysis times.

Identification of Organic Iodine Compounds and Their Transformation Products in Edible Iodized Salt Using Liquid Chromatography-High Resolution Mass Spectrometry.

Science.gov (United States)

Yun, Lifen; Peng, Yue'e; Chang, Qing; Zhu, Qingxin; Guo, Wei; Wang, Yanxin

2017-07-05

The consumption of edible iodized salt is a key strategy to control and eliminate iodine deficiency disorders worldwide. We herein report the identification of the organic iodine compounds present in different edible iodized salt products using liquid chromatography combined with high resolution mass spectrometry. A total of 38 organic iodine compounds and their transformation products (TPs) were identified in seaweed iodine salt from China. Our experiments confirmed that the TPs were generated by the replacement of I atoms from organic iodine compounds with Cl atoms. Furthermore, the organic iodine compound contents in 4 seaweed iodine salt samples obtained from different manufacturers were measured, with significant differences in content being observed. We expect that the identification of organic iodine compounds in salt will be important for estimating the validity and safety of edible iodized salt products.

Extending the range of compounds amenable for gas chromatography-mass spectrometric analysis.

Science.gov (United States)

Fialkov, Alexander B; Gordin, Alexander; Amirav, Aviv

2003-04-04

Gas chromatography-mass spectrometry (GC-MS) suffers from a major limitation in that an expanding number of thermally labile or low volatility compounds of interest are not amenable for analysis. We found that the elution temperatures of compounds from GC can be significantly lowered by reducing the column length, increasing the carrier gas flow rate, reducing the capillary column film thickness and lowering the temperature programming rate. Pyrene is eluted at 287 degrees C in standard GC-MS with a 30 m x 0.25 mm I.D. column with 1-microm DB5ms film and 1-ml/min He column flow rate. In contrast, pyrene is eluted at 79 degrees C in our "Supersonic GC-MS" system using a 1 m x 0.25 mm I.D. column with 0.1-microm DB5ms film and 100-ml/min He column flow rate. A simple model has been invoked to explain the significantly (up to 208 degrees C) lower elution temperatures observed. According to this model, every halving of the temperature programming rate, or number of separation plates (either through increased flow rate or due to reduced column length), results in approximately 20 degrees C lower elution temperature. These considerably lower elution temperatures enable the analysis of an extended range of thermally labile and low volatility compounds, that otherwise could not be analyzed by standard GC-MS. We demonstrate the analysis of large polycyclic aromatic hydrocarbons (PAHs) such as decacyclene with ten fused rings, well above the current GC limit of PAHs with six rings. Even a metalloporphirin such as magnesiumoctaethylporphin was easily analyzed with elution temperatures below 300 degrees C. Furthermore, a range of thermally labile compounds were analyzed including carbamates such as methomyl, aldicarb, aldicarbsulfone and oxamyl, explosives such as pentaerythritol tetranitrate, Tetryl and HMX, and drugs such as reserpine (608 a.m.u.). Supersonic GC-MS was used, based on the coupling of a supersonic molecular beam (SMB) inlet and ion sources with a bench

EJECTION AND CAPTURE DYNAMICS IN RESTRICTED THREE-BODY ENCOUNTERS

International Nuclear Information System (INIS)

Kobayashi, Shiho; Hainick, Yanir; Sari, Re'em; Rossi, Elena M.

2012-01-01

We study the tidal disruption of binaries by a massive point mass (e.g., the black hole at the Galactic center), and we discuss how the ejection and capture preference between unequal-mass binary members depends on which orbit they approach the massive object. We show that the restricted three-body approximation provides a simple and clear description of the dynamics. The orbit of a binary with mass m around a massive object M should be almost parabolic with an eccentricity of |1 – e| ∼ 1/3 1/3 times the binary rotation velocity, it would be abruptly disrupted, and the energy change at the encounter can be evaluated in a simple disruption model. We evaluate the probability distributions for the ejection and capture of circular binary members and for the final energies. In principle, for any hyperbolic (elliptic) orbit, the heavier member has more chance to be ejected (captured), because it carries a larger fraction of the orbital energy. However, if the orbital energy is close to zero, the difference between the two members becomes small, and there is practically no ejection and capture preferences. The preference becomes significant when the orbital energy is comparable to the typical energy change at the encounter. We discuss its implications to hypervelocity stars and irregular satellites around giant planets.

Neutron capture therapy

International Nuclear Information System (INIS)

Jun, B. J.

1998-11-01

The overall state of the art related with neutron capture therapy(NCT) is surveyed. Since the field related with NCT is very wide, it is not intended to survey all related subjects in depth. The primary objective of this report is to help those working for the installation of a NCT facility and a PGNAA(prompt gamma ray neutron activation analysis) system for the boron analysis understand overall NCT at Hanaro. Therefore, while the parts of reactor neutron source and PGNAA are dealt in detail, other parts are limited to the level necessary to understand related fields. For example, the subject of chemical compound which requires intensive knowledge on chemistry, is not dealt as a separated item. However, the requirement of a compound for NCT, currently available compounds, their characteristics, etc. could be understood through this report. Although the subject of cancer treated by NCT is out of the capability of the author, it is dealt focussing its characteristics related with the success of NCT. Each detailed subject is expected to be dealt more detail by specialists in future. This report would be helpful for the researchers working for the NCT to understand related fields. (author). 128 refs., 3 tabs., 12 figs

Neutron dosimetry in boron neutron capture therapy

International Nuclear Information System (INIS)

Fairchild, R.G.; Miola, U.J.; Ettinger, K.V.

1981-01-01

The recent development of various borated compounds and the utilization of one of these (Na 2 B 12 H 11 SH) to treat brain tumors in clinical studies in Japan has renewed interest in neutron capture therapy. In these procedures thermal neutrons interact with 10 B in boron containing cells through the 10 B(n,α) 7 Li reaction producing charged particles with a maximum range of approx. 10μm in tissue. Borated analogs of chlorpromazine, porphyrin, thiouracil and deoxyuridine promise improved tumor uptake and blood clearance. The therapy beam from the Medical Research Reactor in Brookhaven contains neutrons from a modified and filtered fission spectrum and dosimetric consequences of the use of the above mentioned compounds in conjunction with thermal and epithermal fluxes are discussed in the paper. One of the important problems of radiation dosimetry in capture therapy is determination of the flux profile and, hence, the dose profile in the brain. This has been achieved by constructing a brain phantom made of TE plastic. The lyoluminescence technique provides a convenient way of monitoring the neutron flux distributions; the detectors for this purpose utilize 6 Li and 10 B compounds. Such compounds have been synthesized specially for the purpose of dosimetry of thermal and epithermal beams. In addition, standard lyoluminescent phosphors, like glutamine, could be used to determine the collisional component of the dose as well as the contribution of the 14 N(n,p) 14 C reaction. Measurements of thermal flux were compared with calculations and with measurements done with activation foils

Quantification of low molecular weight compounds by MALDI imaging mass spectrometry - A tutorial review.

Science.gov (United States)

Rzagalinski, Ignacy; Volmer, Dietrich A

2017-07-01

Matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry imaging (MSI) permits label-free in situ analysis of chemical compounds directly from the surface of two-dimensional biological tissue slices. It links qualitative molecular information of compounds to their spatial coordinates and distribution within the investigated tissue. MALDI-MSI can also provide the quantitative amounts of target compounds in the tissue, if proper calibration techniques are performed. Obviously, as the target molecules are embedded within the biological tissue environment and analysis must be performed at their precise locations, there is no possibility for extensive sample clean-up routines or chromatographic separations as usually performed with homogenized biological materials; ion suppression phenomena therefore become a critical side effect of MALDI-MSI. Absolute quantification by MALDI-MSI should provide an accurate value of the concentration/amount of the compound of interest in relatively small, well-defined region of interest of the examined tissue, ideally in a single pixel. This goal is extremely challenging and will not only depend on the technical possibilities and limitations of the MSI instrument hardware, but equally on the chosen calibration/standardization strategy. These strategies are the main focus of this article and are discussed and contrasted in detail in this tutorial review. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann. Copyright © 2016 Elsevier B.V. All rights reserved.

Flexible metal-organic framework compounds: In situ studies for selective CO{sub 2} capture

Energy Technology Data Exchange (ETDEWEB)

Allen, A.J., E-mail: andrew.allen@nist.gov [Material Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899-8520 (United States); Espinal, L.; Wong-Ng, W. [Material Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899-8520 (United States); Queen, W.L. [NIST Center for Neutron Research, Gaithersburg, MD 20899-6102 (United States); The Molecular Foundry, Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720 (United States); Brown, C.M. [NIST Center for Neutron Research, Gaithersburg, MD 20899-6102 (United States); Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716 (United States); Kline, S.R. [NIST Center for Neutron Research, Gaithersburg, MD 20899-6102 (United States); Kauffman, K.L. [National Energy Technology Laboratory (NETL), US Department of Energy, Pittsburgh, PA 15236 (United States); Culp, J.T. [National Energy Technology Laboratory (NETL), US Department of Energy, Pittsburgh, PA 15236 (United States); URS Corporation, South Park, PA 15219 (United States); Matranga, C. [National Energy Technology Laboratory (NETL), US Department of Energy, Pittsburgh, PA 15236 (United States)

2015-10-25

Results are presented that explore the dynamic structural changes occurring in two highly flexible nanocrystalline metal-organic framework (MOF) compounds during the adsorption and desorption of pure gases and binary mixtures. The Ni(1,2-bis(4-pyridyl)ethylene)[Ni(CN){sub 4}] and catena-bis(dibenzoylmethanato)-(4,4′-bipyridyl)nickel(II) chosen for this study are 3-D and 1-D porous coordination polymers (PCP) with a similar gate opening pressure response for CO{sub 2} isotherms at 303 K, but with differing degrees of flexibility for structural change to accommodate guest molecules. As such, they serve as a potential model system for evaluating the complex kinetics associated with dynamic structure changes occurring in response to gas adsorption in flexible MOF systems. Insights into the crystallographic changes occurring as the MOF pore structure expands and contracts in response to interactions with CO{sub 2}, N{sub 2}, and CO{sub 2}/N{sub 2} mixtures have been obtained from in situ small-angle neutron scattering and neutron diffraction, combined with ex situ X-ray diffraction structure measurements. The role of structure in carbon capture functionality is discussed with reference to the ongoing characterization challenges and a possible materials-by-design approach. - Graphical abstract: We present in situ small-angle neutron scattering results for two flexible metal-organic frameworks (MOFs). The figure shows that for one (NiBpene, high CO{sub 2} adsorption) the intensity of the Bragg peak for the expandable d-spacing most associated with CO{sub 2} adsorption varies approximately with the isotherm, while for the other (NiDBM-Bpy, high CO{sub 2} selectivity) the d-spacing, itself, varies with the isotherm. The cartoons show the proposed modes of structural change. - Highlights: • Dynamic structures of two flexible MOF CO{sub 2} sorbent compounds are compared in situ. • These porous solid sorbents serve as models for pure & dual gas adsorption. • Different

CHAOTIC CAPTURE OF NEPTUNE TROJANS

International Nuclear Information System (INIS)

Nesvorny, David; Vokrouhlicky, David

2009-01-01

Neptune Trojans (NTs) are swarms of outer solar system objects that lead/trail planet Neptune during its revolutions around the Sun. Observations indicate that NTs form a thick cloud of objects with a population perhaps ∼10 times more numerous than that of Jupiter Trojans and orbital inclinations reaching ∼25 deg. The high inclinations of NTs are indicative of capture instead of in situ formation. Here we study a model in which NTs were captured by Neptune during planetary migration when secondary resonances associated with the mean-motion commensurabilities between Uranus and Neptune swept over Neptune's Lagrangian points. This process, known as chaotic capture, is similar to that previously proposed to explain the origin of Jupiter's Trojans. We show that chaotic capture of planetesimals from an ∼35 Earth-mass planetesimal disk can produce a population of NTs that is at least comparable in number to that inferred from current observations. The large orbital inclinations of NTs are a natural outcome of chaotic capture. To obtain the ∼4:1 ratio between high- and low-inclination populations suggested by observations, planetary migration into a dynamically excited planetesimal disk may be required. The required stirring could have been induced by Pluto-sized and larger objects that have formed in the disk.

Attachment to a mass spectrometer for studying the processes of semiconductor compound deposition from a gaseous phase

International Nuclear Information System (INIS)

Belousov, V.I.; Zhuravlev, G.I.; Popenko, N.I.; Novozhilov, A.F.; Matveev, I.V.; Murav'ev, V.V.

1984-01-01

An attachment to the mass spectrometer for studying the processes of semiconductor compounds deposition from a gaseous phase at the pressure of 1x10 5 Pa and the temperature of 400-1300 K is described. The attachment consists of the Neer ion source with ionization section cooled upto the temperature of liquid nitrogen, a two-zone vacuum furnace, and a quartz epitaxy reactor of the horzontal type.The attachment is equipped with the systems of process gas distribution in 5 flows and temperature stabilization. The rate of mass spectrum recording constitutes 2 mass/s at the resolution being equal to 1000 at the 10% level. The sensitivity at the steam-gas mixture components partial pressure determination constitutes 1x10 -4 Pa

Measurements of neutron capture cross sections of wolfram and thulium

International Nuclear Information System (INIS)

Xia Yijun; Wang Chunhao; Yang Jingfu; Yang Zhihua; Luo Xiaobing

1992-01-01

The neutron capture cross sections of wolfram and thulium were measured in the energy range from 10 to 100 KeV using gold as the standard. Kinematically collimated neutrons were produced via the 7 Li(p, n) 7 Be reaction with a 2.5 MV pulsed Van de Graaff accelerator at Sichuan University. The capture events were detected by a pair of Moxon-Rae detectors. Time-of-flight technique was used to improve the signal-background ratio. The present results are compared with data by other authors. The capture cross section were calculated from 10 to 100 KeV for two nuclides by the Hauser-Feshbach statistical theory with width fluctuation correction. The nonstatistical effects such as potential capture and radiative capture in elastic and inelastic channels of a compound nucleus were included in the calculations. The calculated results show that the nonstatistical contribution to the capture cross sections is negligible compared with that of the statistical effects

Capture and fission with DANCE and NEUANCE

Energy Technology Data Exchange (ETDEWEB)

Jandel, M.; Baramsai, B.; Bond, E.; Rusev, G.; Walker, C.; Bredeweg, T.A.; Chadwick, M.B.; Couture, A.; Fowler, M.M.; Hayes, A.; Kawano, T.; Mosby, S.; Stetcu, I.; Taddeucci, T.N.; Talou, P.; Ullmann, J.L.; Vieira, D.J.; Wilhelmy, J.B. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

2015-12-15

A summary of the current and future experimental program at DANCE is presented. Measurements of neutron capture cross sections are planned for many actinide isotopes with the goal to reduce the present uncertainties in nuclear data libraries. Detailed studies of capture gamma rays in the neutron resonance region will be performed in order to derive correlated data on the de-excitation of the compound nucleus. New approaches on how to remove the DANCE detector response from experimental data and retain the correlations between the cascade gamma rays are presented. Studies on {sup 235}U are focused on quantifying the population of short-lived isomeric states in {sup 236}U after neutron capture. For this purpose, a new neutron detector array NEUANCE is under construction. It will be installed in the central cavity of the DANCE array and enable the highly efficient tagging of fission and capture events. In addition, developments of fission fragment detectors are also underway to expand DANCE capabilities to measurements of fully correlated data on fission observables. (orig.)

Liquid separation techniques coupled with mass spectrometry for chiral analysis of pharmaceuticals compounds and their metabolites in biological fluids.

Science.gov (United States)

Erny, G L; Cifuentes, A

2006-02-24

Determination of the chiral composition of drugs is nowadays a key step in order to determine purity, activity, bioavailability, biodegradation, etc., of pharmaceuticals. In this article, works published for the last 5 years on the analysis of chiral drugs by liquid separation techniques coupled with mass spectrometry are reviewed. Namely, chiral analysis of pharmaceuticals including, e.g., antiinflammatories, antihypertensives, relaxants, etc., by liquid chromatography-mass spectrometry and capillary electrophoresis-mass spectrometry are included. The importance and interest of the analysis of the enantiomers of the active compound and its metabolites in different biological fluids (plasma, urine, cerebrospinal fluid, etc.) are also discussed.

[Determination of flavor compounds in foxtail millet wine by gas chromatography-mass spectrometry coupled with headspace solid phase microextraction].

Science.gov (United States)

Liu, Jingke; Zhang, Aixia; Li, Shaohui; Zhao, Wei; Zhang, Yuzong; Xing, Guosheng

2017-11-08

To comprehensively understand flavor compounds and aroma characteristics of foxtail millet wine, extraction conditions were optimized with 85 μm polyacrylate (PA), 100 μm polydimethylsiloxane (PDMS), 75 μm carboxen (CAR)/PDMS and 50/30 μm divinylbenzene (DVB)/CAR/PDMS fibers. The flavor compounds in foxtail millet wine were investigated by gas chromatography-mass spectrometry (GC-MS) coupled with headspace solid phase microextraction (HS-SPME), and the odor characteristics and intensity were analyzed by odor active values (OAVs). The samples of 8 mL were placed in headspace vials with 1.5 g NaCl, then the headspace vials were heated at 60℃ for 40 min. Using HS-SPME with different fibers, a total of 55 flavor compounds were identified from the samples, including alcohols, esters, benzene derivatives, hydrocarbons, acids, aldehydes, ketones, terpenes, phenols and heterocycle compounds. The main flavor compounds were alcohols compounds. According to their OAVs, phenylethyl alcohol, styrene, 1-methyl-naphthalene, 2-methyl-naphthalene, benzaldehyde, benzeneacetaldehyde and 2-methoxy-phenol were established to be odor-active compounds. Phenylethyl alcohol and benzeneacetaldehyde were the most prominent odor-active compounds. PA and PDMS fibers had good extraction effect for polar and nonpolar compounds, respectively. CAR/PDMS and DVB/CAR/PDMS provided a similar compounds profile for moderate polar compounds. This research comprehensively determined flavor compounds of foxtail millet wine, and provided theoretical basis for product development and quality control.

Biodistribution of Boron compounds in an experimental model of liver metastases for Boron Neutron Capture (BNCT) Studies

International Nuclear Information System (INIS)

Garabalino, Marcela A.; Monti Hughes, Andrea; Molinari, Ana J.; Heber, Elisa M.; Pozzi, Emiliano C.C.; Itoiz, Maria E.; Trivillin, Veronica A.; Schwint, Amanda E.; Nievas, Susana; Aromando, Romina F.

2009-01-01

Boron Neutron Capture Therapy (BNCT) is a binary treatment modality that involves the selective accumulation of 10 B carriers in tumors followed by irradiation with thermal or epithermal neutrons. The high linear energy transfer alpha particles and recoiling 7 Li nuclei emitted during the capture of a thermal neutron by a 10 B nucleus have a short range and a high biological effectiveness. Thus, BNCT would potentially target neoplastic tissue selectively. In previous studies we demonstrated the therapeutic efficacy of different BNCT protocols in an experimental model of oral cancer. More recently we performed experimental studies in normal rat liver that evidenced the feasibility of treating liver metastases employing a novel BNCT protocol proposed by JEC based on ex-situ treatment and partial liver auto-transplant. The aim of the present study was to perform biodistribution studies with different boron compounds and different administration protocols to determine the protocols that would be therapeutically useful in 'in vivo' BNCT studies at the RA-3 Nuclear Reactor in an experimental model of liver metastases in rats. Materials and Methods. A total of 70 BDIX rats (Charles River Lab., MA, USA) were inoculated in the liver with syngeneic colon cancer cells DH/DK12/TRb (ECACC, UK) to induce the development of subcapsular metastatic nodules. 15 days post-inoculation the animals were used for biodistribution studies. A total of 11 protocols were evaluated employing the boron compounds boronophenylalanine (BPA) and GB-10 (Na 2 10 B 1 -0H 10 ), alone or combined employing different doses and administration routes. Tumor, normal tissue and blood samples were processed for boron measurement by ICP-OES. Results. Several protocols proved potentially useful for BNCT studies in terms of absolute boron concentration in tumor and preferential uptake of boron by tumor tissue, i.e. BPA 15.5 mg 10 B/kg iv + GB-10 50 mg 10 B/kg iv; BPA 46.5 mg 10 B/kg ip; BPA 46.5 mg 10 B/kg ip

40 CFR 63.3165 - How do I determine the emission capture system efficiency?

Science.gov (United States)

2010-07-01

... system, and coating solvent flash-off and coating curing and drying occurs within the capture system. For... Compound (VOC) Released from Solventborne Automotive Coatings and Available for Removal in a VOC Control... Determining the Amount of Volatile Organic Compound (VOC) Released from Waterborne Automotive Coatings and...

Characterization of odor-active compounds in cooked meat of farmed obscure puffer (Takifugu obscurus using gas chromatography–mass spectrometry–olfactometry

Directory of Open Access Journals (Sweden)

Ning-Ping Tao

2014-12-01

Full Text Available The volatile and odor-active compounds in cooked meat of farmed obscure puffer (Takifugu obscurus were analyzed by gas chromatography–mass spectrometry–olfactometry (GC–MS–O. The volatile compounds were extracted by the simultaneous distillation–extraction (SDE method, then separated and identified by GC–MS. Odor-active compounds in the SDE extract were characterized by GC–MS–O. A total of 68 volatile compounds were found, including 23 aldehydes, 10 alcohols, nine ketones, 17 N- or S-containing compounds and aromatics, three acids, three alkanes, and three esters. Of these, 31 odor-active compounds were detected and identified. Trimethylamine (fishy, octanal (grassy, leafy, green, (E-2-octenal (roast, fatty, 1-octen-3-ol (fishy, fatty, mushroom, grassy, 2-ethyl-1-hexanethiol (cooked fish, (E,E-2,4-octadienal (cooked meat, sweet, 2-acetylthiazole (meaty, roast, nutty, sulfur, 2-acetylpyrrole (nutty, walnut, bread were identified as the key odorants in the cooked meat of farmed obscure puffer based on posterior intensity and time-intensity methods.

CAPTURE OF PLANETESIMALS BY GAS DRAG FROM CIRCUMPLANETARY DISKS

International Nuclear Information System (INIS)

Fujita, Tetsuya; Ohtsuki, Keiji; Suetsugu, Ryo; Tanigawa, Takayuki

2013-01-01

Growing giant planets have circumplanetary disks around them in the late stage of their formation if their mass is sufficiently large. We examine capture of relatively large planetesimals that are decoupled from the gas inflow, due to gas drag from a circumplanetary disk of a growing giant planet. Assuming that the structure of the circumplanetary disk is axisymmetric, and solving the three-body problem including gas drag, we perform analytic and numerical calculations for capture of planetesimals. When planetesimal random velocity is small, planetesimals approaching in the retrograde direction are more easily captured, owing to their larger velocity relative to the gas. Planetesimals with large orbital inclinations interact with the disk for a short period of time and show lower capture rates. The effect of ablation on capture rates seems insignificant, although mass loss due to ablation would be significant in the case of high random velocity. We also examine the effect of non-uniform radial distribution of planetesimals in the protoplanetary disk due to gap opening by the planet. When the random velocity of planetesimals is small, the planetesimal capture rate decreases rapidly as the half width of the gap in the planetesimal disk increases from two planetary Hill radii to three planetary Hill radii; planetesimals with low random velocities cannot approach the planet in the case of a sufficiently wide gap. Our results show that the radial distribution and random velocity of planetesimals in the protoplanetary disk are essentially important for the understanding of capture of planetesimals by circumplanetary disks

Structure-dependent degradation of polar compounds in weathered oils observed by atmospheric pressure photo-ionization hydrogen/deuterium exchange ultrahigh resolution mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Islam, Ananna; Kim, Donghwi [Kyungpook National University, Department of Chemistry, Daegu 702-701 (Korea, Republic of); Yim, Un Hyuk; Shim, Won Joon [Oil and POPs Research Group, Korea Institute of Ocean Science and Technology, KIOST, Geoje 656-834 (Korea, Republic of); Kim, Sunghwan, E-mail: sunghwank@knu.ac.kr [Kyungpook National University, Department of Chemistry, Daegu 702-701 (Korea, Republic of); Green Nano Center, Department of Chemistry, Daegu 702-701 (Korea, Republic of)

2015-10-15

Highlights: • We examined source crude oil and weathered oils from M/V Hebei accident. • APPI hydrogen/deuterium exchange ultrahigh mass spectrometry was applied. • N{sub 1} class compounds with 2° and/or 3° amine decrease in larger scale than pyridines. • Preferential degradation of nitrogen-containing compounds was confirmed. • Significant increase in S{sub 1}O{sub 1} compounds was observed as the weathering proceeds. - Abstract: The resin fractions of fresh mixtures of three oils spilled during the M/V Hebei Spirit oil spill, as well as weathered oils collected at weathering stages II and IV from the oil spill site were analyzed and compared by atmospheric pressure photo-ionization hydrogen/deuterium exchange mass spectrometry (HDX MS). The significantly decreased abundance of N{sup +}· and [N − H + D]{sup +} ions suggested that secondary and tertiary amine-containing compounds were preferentially degraded during the early stage of weathering. [N + H]{sup +} and [N + D]{sup +} ions previously attributed to pyridine-type compounds degraded more slowly than secondary and tertiary amine-containing compounds. The preferential degradation of nitrogen-containing compounds was confirmed by photo-degradation experiments using 15 standard compounds. In addition, significant increases of [S{sub 1}O{sub 1} + H]{sup +} and [S{sub 1}O{sub 1} + D]{sup +} ions with higher DBE values were observed from fresh oil mixtures as compared to stages II and IV samples, and that could be linked with the decrease of higher DBE compounds of the S{sub 1} class. This study presented convincing arguments and evidence demonstrating that secondary and tertiary amines were more vulnerable to photo-degradation than compounds containing pyridine, and hence, preferential degradation depending on chemical structures must be considered in the production of hazardous or toxic components.

Structure-dependent degradation of polar compounds in weathered oils observed by atmospheric pressure photo-ionization hydrogen/deuterium exchange ultrahigh resolution mass spectrometry

International Nuclear Information System (INIS)

Islam, Ananna; Kim, Donghwi; Yim, Un Hyuk; Shim, Won Joon; Kim, Sunghwan

2015-01-01

Highlights: • We examined source crude oil and weathered oils from M/V Hebei accident. • APPI hydrogen/deuterium exchange ultrahigh mass spectrometry was applied. • N 1 class compounds with 2° and/or 3° amine decrease in larger scale than pyridines. • Preferential degradation of nitrogen-containing compounds was confirmed. • Significant increase in S 1 O 1 compounds was observed as the weathering proceeds. - Abstract: The resin fractions of fresh mixtures of three oils spilled during the M/V Hebei Spirit oil spill, as well as weathered oils collected at weathering stages II and IV from the oil spill site were analyzed and compared by atmospheric pressure photo-ionization hydrogen/deuterium exchange mass spectrometry (HDX MS). The significantly decreased abundance of N + · and [N − H + D] + ions suggested that secondary and tertiary amine-containing compounds were preferentially degraded during the early stage of weathering. [N + H] + and [N + D] + ions previously attributed to pyridine-type compounds degraded more slowly than secondary and tertiary amine-containing compounds. The preferential degradation of nitrogen-containing compounds was confirmed by photo-degradation experiments using 15 standard compounds. In addition, significant increases of [S 1 O 1 + H] + and [S 1 O 1 + D] + ions with higher DBE values were observed from fresh oil mixtures as compared to stages II and IV samples, and that could be linked with the decrease of higher DBE compounds of the S 1 class. This study presented convincing arguments and evidence demonstrating that secondary and tertiary amines were more vulnerable to photo-degradation than compounds containing pyridine, and hence, preferential degradation depending on chemical structures must be considered in the production of hazardous or toxic components

Gas Chromatographic-Ion Trap Mass Spectrometric Analysis of Volatile Organic Compounds by Ion-Molecule Reactions Using the Electron-Deficient Reagent Ion CCl{3/+}

Science.gov (United States)

Wang, Cheng-Zhong; Su, Yue; Wang, Hao-Yang; Guo, Yin-Long

2011-10-01

When using tetrachloromethane as the reagent gas in gas chromatography-ion trap mass spectrometry equipped with hybrid ionization source, the cation CCl{3/+} was generated in high abundance and further gas-phase experiments showed that such an electron-deficient reagent ion CCl{3/+} could undergo interesting ion-molecule reactions with various volatile organic compounds, which not only present some informative gas-phase reactions, but also facilitate qualitative analysis of diverse volatile compounds by providing unique mass spectral data that are characteristic of particular chemical structures. The ion-molecule reactions of the reagent ion CCl{3/+} with different types of compounds were studied, and results showed that such reactions could give rise to structurally diagnostic ions, such as [M + CCl3 - HCl]+ for aromatic hydrocarbons, [M - OH]+ for saturated cyclic ether, ketone, and alcoholic compounds, [M - H]+ ion for monoterpenes, M·+ for sesquiterpenes, [M - CH3CO]+ for esters, as well as the further fragment ions. The mechanisms of ion-molecule reactions of aromatic hydrocarbons, aliphatic ketones and alcoholic compounds with the reagent ion CCl{3/+} were investigated and proposed according to the information provided by MS/MS experiments and theoretical calculations. Then, this method was applied to study volatile organic compounds in Dendranthema indicum var. aromaticum and 20 compounds, including monoterpenes and their oxygen-containing derivatives, aromatic hydrocarbon and sesquiterpenes were identified using such ion-molecule reactions. This study offers a perspective and an alternative tool for the analysis and identification of various volatile compounds.

Inductively coupled plasma-mass spectrometry for elemental analysis and isotope ratio determinations in individual organic compounds separated by gas chromatography

International Nuclear Information System (INIS)

Chong, N.S.; Houk, R.S.

1987-01-01

A gas chromatograph (GC) with a packed column was interfaced to an inductively coupled plasma-mass spectrometer (ICP-MS) to yield atomic mass spectra from volatile organic compounds. Atomization of injected compounds was nearly complete and independent of molecular structure, so that elemental ratios could be determined. Detection limits were in the range 0.001 to 400 ng s -1 , depending on the ionization energy of the element and its abundance in the background spectrum. The relative standard deviation of measured isotope ratios varied from 0.4% for Br (i.e., a ratio close to unity) to 18% for N (a very large ratio). Thus, GC-ICP-MS provides elemental and isotope ratio information that is complementary to the molecular information derived from GC-MS with conventional ionization methods

Gadolinium as an element for neutron capture therapy

International Nuclear Information System (INIS)

Brugger, R.M.; Liu, H.B.; Laster, B.H.; Gordon, C.R.; Greenberg, D.D.; Warkentien, L.S.

1992-01-01

At BNL, preparations are being made to test in vitro compounds containing Gd and compare their response to the response of GD-DTPA to determine if one or several compounds can be located that enter the cells and enhance the Auger effect. Two similar rotators with positions for cell vials that have been constructed for these tests. The first rotator is made of only paraffin which simulates healthy tissue and provides control curves. The second rotator has 135 ppM of Gd-157 in the paraffin to simulate a Gd loaded tumor. Cells are irradiated in vials in the paraffin rotator and in the Gd-paraffin rotator at the epithermal beam of the Brookhaven Medical Research Reactor (BMRR). This produces an irradiation similar to what a patient would receive In an actual treatment. A combination of irradiations are made with both rotators; with no Gd compound or IdUrd In the cell media, with only Gd compound in the cell media and with both Gd compound and IdUrd in the cell media. The first set shows the effects of gamma rays from the H(n,gamma) reaction and the prompt gamma rays from capture of neutrons by Gd. The second set shows if there is any effect of Gd being in the cell media or inside the cells, i.e., an Auger effect. The third set shows the effect of enhancement by the IdUrd produced by the gamma rays from neutrons captured by either H or Gd. The fourth set combines all of the reactions and enhancements. Preliminary calculations and physical measurements of the doses that the cells will receive In these rotators have been made

Study of the interaction of boron-containing amino acids for the neutron capture therapy with biologically interesting compounds by using 'three-spot zone electrophoresis'

International Nuclear Information System (INIS)

Kitaoka, Yoshinori; Kobayashi, Mitsue; Morimoto, Tsuguhiro; Kirihata, Mitsunori; Ichimoto, Itsuo.

1995-01-01

As the boron carriers for boron neutron capture therapy, p-borono phenylalanine (BPA) is the boron compound which has been clinically used together with sodium borocaptate. It was found by the electrophoresis behavior that the BPA interacted with organic carboxylic acids in its dissolved state. In this paper, the electrophoresis behavior of general amino acids as seen in three-spot zone electrophoresis and the peculiar interaction of the amino acids having dihydroxyboryl radical are described. Zone electrophoresis has been developed as separation means, and three-spot process excludes the errors due to accidental factors as far as possible. The behaviors of zone electrophoresis of ordinary neutral amino acids, orthoboric acid and p-BPA are reported. For utilizing the features of boron neutron capture therapy, it is necessary to develop the carrier which is singularly taken into cancer cells. There is not a good method for discriminating normal cells and cancer cells. As for the administration of BPA to patients, its solubility is insufficient, therefore, its fructose complex has been used. The research on the biochemical peculiarity of boron is important. (K.I.)

Tandem Extraction/Liquid Chromatography-Mass Spectrometry Protocol for the Analysis of Acrylamide and Surfactant-related Compounds in Complex Aqueous Environmental Samples

Science.gov (United States)

The development of a liquid chromatography‐mass spectrometry (LC‐MS)‐based strategy for the detection and quantitation of acrylamide and surfactant‐related compounds in aqueous complex environmental samples.

Guided episodic sampling for capturing and characterizing industrial plumes

Science.gov (United States)

Ou-Yang, Chang-Feng; Liao, Wei-Cheng; Chang, Chih-Chung; Hsieh, Hsin-Cheng; Wang, Jia-Lin

2018-02-01

An integrated sampling technique, dubbed trigger sampling, was developed to capture characteristic industrial emissions or plumes. In the field experiment, a hydrogen sulfide (H2S) analyzer was used as the triggering instrument at the boundary of a refinery plant due to frequent complaints of foul smell from local residents. Ten episodic samples were captured when the H2S level surpassed the prescribed trigger level of 8.5 ppbv over a three-day period. Three non-episodic (blank) samples and 23 road-side samples were also collected for comparison. All the 36 flask samples were analyzed by gas chromatography-mass spectrometry/flame ionization detection (GC-MS/FID) for 108 volatile organic compounds (VOCs). The total VOC abundance of the event samples was exceedingly higher than the non-episodic samples by over 80 times in the extreme case. Alkanes were found to be the dominant constituents in the event samples, amounting to over 90% of the total VOC concentrations vs. only 30-40% for the blank and metropolitan samples. In addition, light alkanes in the event samples were highly correlated with the trigger species H2S (R2 = 0.82), implying their common origin. The matrix of chemical composition vs. sample types permitted easy visualization of the dominance of light alkanes for the event samples compared to other types of samples. Principle component analysis (PCA) identified two major contributors to cover 93% of the total variance arising from the 36 samples, further quantifying the distinction of the triggered episodic samples from the contrast samples. The proposed trigger sampling is a coupling of fast-and-slow measurement techniques. In this example, the fast-response H2S analyzer served to "guide" sampling to capture industrial plumes which were then characterized by a relatively slow method of GC-MS/FID for detailed chemical composition representative of the prominent sources.

Rapid profiling of antimicrobial compounds characterising B. subtilis TR50 cell-free filtrate by high-performance liquid chromatography coupled to high-resolution Orbitrap™ mass spectrometry.

Science.gov (United States)

Monaci, Linda; Quintieri, Laura; Caputo, Leonardo; Visconti, Angelo; Baruzzi, Federico

2016-01-15

Several Bacillus strains, typically isolated from different food sources, represent renowned producers of a multitude of low and high molecular weight compounds, including lipopeptides and macrolactones, with an importance for their antimicrobial activity. The high homology shared by many of these compounds also occurring as closely related isoforms poses a challenge in their prompt detection. Identification and structural elucidation is generally achieved by matrix-assisted laser desorption/ionization (MALDI) or liquid chromatography (LC) coupled to mass spectrometry (MS) after a pre-fractionation and/or purification step of the extract. In this paper we report the application of a method based on LC separation and high-resolution Orbitrap™-based MS for the rapid screening of raw filtrate of the strain Bacillus subtilis TR50 endowed with antimicrobial activity, without requiring any sample pre-treatment. Upon direct analysis of the cell-free filtrate of Bacillus subtilis TR50 by high-resolution mass spectrometry (HRMS), different compounds families, that proved to exert a remarked antimicrobial activity against several foodborne pathogens, can be readily displayed along the chromatographic run. Among them, three different classes were identified and characterized belonging to the iturin, fengycin and surfactin groups. The high resolving power and accurate mass accuracy provided by the HRMS system in use ensured an enhanced selectivity compared to other mass spectrometers. In addition, after activation of the HCD cell, the HR-MS/MS spectra can provide insights in the structural elucidation of several compounds. The acquisition of HRMS spectra of raw filtrates of subtilis strains allows untargeted analysis of the major classes of compounds produced to be performed, thus facilitating identification of other unknown bioactive molecules after retrospective analysis. These features make this approach a fast tool applicable to the rapid screening and further

Characterization of the Key Aroma Compounds in Proso Millet Wine Using Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry

Directory of Open Access Journals (Sweden)

Jingke Liu

2018-02-01

Full Text Available The volatile compounds in proso millet wine were extracted by headspace solid-phase microextraction (85 μm polyacrylate (PA, 100 μm polydimethylsiloxane (PDMS, 75 μm Carboxen (CAR/PDMS, and 50/30 μm divinylbenzene (DVB/CAR/PDMS fibers, and analyzed using gas chromatography-mass spectrometry; the odor characteristics and intensities were analyzed by the odor activity value (OAV. Different sample preparation factors were used to optimize this method: sample amount, extraction time, extraction temperature, and content of NaCl. A total of 64 volatile compounds were identified from the wine sample, including 14 esters, seven alcohols, five aldehydes, five ketones, 12 benzene derivatives, 12 hydrocarbons, two terpenes, three phenols, two acids, and two heterocycles. Ethyl benzeneacetate, phenylethyl alcohol, and benzaldehyde were the main volatile compounds found in the samples. According to their OAVs, 14 volatile compounds were determined to be odor-active compounds (OAV > 1, and benzaldehyde, benzeneacetaldehyde, 1-methyl-naphthalene, 2-methyl-naphthalene, and biphenyl were the prominent odor-active compounds (OAV > 50, having a high OAV. Principal component analysis (PCA showed the difference of distribution of the 64 volatile compounds and 14 odor-active compounds with four solid-phase microextraction (SPME fibers.

Characterization of aromatic organosulfur model compounds relevant to fossil fuels by using atmospheric pressure chemical ionization with CS2 and high-resolution tandem mass spectrometry.

Science.gov (United States)

Tang, Weijuan; Sheng, Huaming; Jin, Chunfen; Riedeman, James S; Kenttämaa, Hilkka I

2016-04-15

The chemistry of desulfurization involved in processing crude oil is greatly dependent on the forms of sulfur in the oil. Sulfur exists in different chemical bonding environments in fossil fuels, including those in thiophenes and benzothiophenes, thiols, sulfides, and disulfides. In this study, the fragmentation behavior of the molecular ions of 17 aromatic organosulfur compounds with various functionalities was systematically investigated by using high-resolution tandem mass spectrometry. Multiple-stage tandem mass spectrometric experiments were carried out using a linear quadrupole ion trap (LQIT) equipped with an atmospheric pressure chemical ionization (APCI) source. (+)APCI/CS2 was used to generate stable dominant molecular ions for all the compounds studied except for three sulfides that also showed abundant fragment ions. The LQIT coupled with an orbitrap mass spectrometer was used for elemental composition analysis, which facilitated the identification of the neutral molecules lost during fragmentation. The characteristic fragment ions generated in MS(2) and MS(3) experiments provide clues for the chemical bonding environment of sulfur atoms in the examined compounds. Upon collision-induced dissociation (CID), the molecular ions can lose the sulfur atom in a variety of ways, including as S (32 Da), HS(•) (33 Da), H2 S (34 Da), CS (44 Da), (•) CHS (45 Da) and CH2 S (46 Da). These neutral fragments are not only indicative of the presence of sulfur, but also of the type of sulfur present in the compound. Generally, losses of HS(•) and H2 S were found to be associated with compounds containing saturated sulfur functionalities, while losses of S, CS and (•) CHS were more common for heteroaromatic sulfur compounds. High-resolution tandem mass spectrometry with APCI/CS2 ionization is a viable approach to determining the types of organosulfur compounds. It can potentially be applied to analysis of complex mixtures, which is beneficial to improving the

Direct sample introduction-gas chromatography-mass spectrometry for the determination of haloanisole compounds in cork stoppers.

Science.gov (United States)

Cacho, J I; Nicolás, J; Viñas, P; Campillo, N; Hernández-Córdoba, M

2016-12-02

A solventless analytical method is proposed for analyzing the compounds responsible for cork taint in cork stoppers. Direct sample introduction (DSI) is evaluated as a sample introduction system for the gas chromatography-mass spectrometry (GC-MS) determination of four haloanisoles (HAs) in cork samples. Several parameters affecting the DSI step, including desorption temperature and time, gas flow rate and other focusing parameters, were optimized using univariate and multivariate approaches. The proposed method shows high sensitivity and minimises sample handling, with detection limits of 1.6-2.6ngg -1 , depending on the compound. The suitability of the optimized procedure as a screening method was evaluated by obtaining decision limits (CCα) and detection capabilities (CCβ) for each analyte, which were found to be in 6.9-11.8 and 8.7-14.8ngg -1 , respectively, depending on the compound. Twenty-four cork samples were analysed, and 2,4,6-trichloroanisole was found in four of them at levels between 12.6 and 53ngg -1 . Copyright © 2016 Elsevier B.V. All rights reserved.

Transient modeling of electrochemically assisted CO2 capture and release

DEFF Research Database (Denmark)

Singh, Shobhana; Stechel, Ellen B.; Buttry, Daniel A.

2017-01-01

to analyze the time-dependent behavior of CO2 capture and electro-migration transport across the cell length. Given high nonlinearity of the system, we used a finite element method (FEM) to numerically solve the coupled mass transport equations. The model describes the concentration profiles by taking......The present work aims to develop a model of a new electrochemical CO2 separation and release technology. We present a one-dimensional transient model of an electrochemical cell for point source CO2 capture and release, which mainly focuses on the simultaneous mass transport and complex chemical...... reactions associated with the separation process. For concreteness, we use an ionic liquid (IL) with 2 M thiolate anion (RS−) in 1 M disulfide (RSSR) as an electrolyte in the electrochemical cell to capture, transport and release CO2 under standard operating conditions. We computationally solved the model...

Mass spectrometric investigation of cyclication of diazo compounds. XI. Cyclization of 1-diazo-4-methoxycarbonyl-2-butanones

International Nuclear Information System (INIS)

Lebedev, A.T.; Kazaryan, A.G.; Sharbatyan, P.A.; Sipyagin, A.M.; Kartsev, V.G.; Petrosyan, V.S.

1988-01-01

On the basis of the electron-impact mass spectra of a series of 1-diazo-4-methoxycarbonyl-2-butanones, the data from high-solution mass spectrometry, and the spectrum of the deuterated analog it was shown that the [M-N 2 ] +center-dot ions formed at the first stage in the fragmentation of the molecular ions of these compounds are partly stabilized with the formation of pseudomolecular ions of oxolanones. The molecular ions of the diazo ketones themselves can dissociate in various directions. The many-path dissociation makes it possible to suppose that the yield of oxolanones formed during cyclization in solution under the influence of acidic agents is small

Applications of Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry (SPME-GC/MS in the Study of Grape and Wine Volatile Compounds

Directory of Open Access Journals (Sweden)

Annarita Panighel

2014-12-01

Full Text Available Volatile compounds are responsible for the wine “bouquet”, which is perceived by sniffing the headspace of a glass, and of the aroma component (palate-aroma of the overall flavor, which is perceived on drinking. Grape aroma compounds are transferred to the wine and undergo minimal alteration during fermentation (e.g., monoterpenes and methoxypyrazines; others are precursors of aroma compounds which form in winemaking and during wine aging (e.g., glycosidically-bound volatile compounds and C13-norisoprenoids. Headspace solid phase microextraction (HS-SPME is a fast and simple technique which was developed for analysis of volatile compounds. This review describes some SPME methods coupled with gas chromatography/mass spectrometry (GC/MS used to study the grape and wine volatiles.

Electron capture on 20Ne and the ultimate fate of stars in the mass range 8-10 M⊙

International Nuclear Information System (INIS)

Kirsebom, Oliver S.; Cederkall, Joakim; Jenkins, David G.; Joshi, Pankaj; Julin, Rauno; Kankainen, Anu; Trzaska, Wladyslaw H.; Kibedi, Tibor; Tengblad, Olof

2016-01-01

Knowledge of the electron-capture rate on 20 Ne is of critical importance to understand the final evolution of stars in the mass range 8-10M⊙. A recent study has highlighted the importance of the second-forbidden transition between the ground states of 20 Ne and 20 F, which is believed to dominate the capture rate in an important temperature-density range. The strength of this transition is, however, not well constrained, neither experimentally nor theoretically, making an experimental determination highly desirable. The transition strength can be determined from the branching ratio of the inverse transition in the decay of 20 F, for which the experimental upper limit is 10 -5 , while the most recent theoretical prediction is 1.3 x 10 -6 . To facilitate an experimental determination of the branching ratio we are refurbishing an intermediate-image magnetic spectrometer capable of focusing 7 MeV electrons, and designing a scintillator detector surrounded by an active cosmic-ray veto shield, which will serve as an energy- dispersive device at the focal plane. In this contribution, GEANT4 simulations of the expected performance of the setup will be presented and the astrophysical motivation for the experiment will be discussed. (author)

Characterization of phenolic compounds in Helichrysum melaleucum by high-performance liquid chromatography with on-line ultraviolet and mass spectrometry detection.

Science.gov (United States)

Gouveia, Sandra C; Castilho, Paula C

2010-07-15

Helicrysum melaleucum is a medicinal plant traditionally used in the islands of the Macaronesia region for the treatment of respiratory diseases. In this work, the phenolic compounds of Helicrysum melaleucum plants collected in different geographical locations of Madeira Island and their morphological parts (total aerial parts, leaves, flowers and stems) were extracted and analyzed separately by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-DAD/ESI-MS(n)). A total of 68 compounds were characterized based mainly on their UV and mass spectra. These included derivatives of O-glycosylated flavonoids (flavonol and flavones type), quinic acid, caffeic acid, lignans and polyphenols. The flowers were found to be the morphological part with higher variety of phenolic compounds. The large differences in the phenolic composition of plants collected from different geographical locations allowed the identification of a few components, such as pinoresinol and methoxylated flavone derivatives, likely to be useful as geographical markers. Also, these results promote further comparison of the bioactivities of the different samples analyzed. This paper marks the first report on the chemical analysis of Helichrysum melaleucum species. Copyright 2010 John Wiley & Sons, Ltd.

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.

Occurrence of pharmaceutical compounds in urban wastewater: Removal, mass load and environmental risk after a secondary treatment—A review

International Nuclear Information System (INIS)

Verlicchi, P.; Al Aukidy, M.; Zambello, E.

2012-01-01

This review focuses on 118 pharmaceuticals, belonging to seventeen different therapeutic classes, detected in raw urban wastewater and effluent from an activated sludge system, a usual treatment adopted for urban wastewaters worldwide prior to final discharge into surface water bodies. Data pertaining to 244 conventional activated sludge systems and 20 membrane biological reactors are analysed and the observed ranges of variability of each selected compound in their influent and effluent reported, with particular reference to the substances detected most frequently and in higher concentrations. A snapshot of the ability of these systems to remove such compounds is provided by comparing their global removal efficiencies for each substance. Where possible, the study then evaluates the average daily mass load of the majority of detected pharmaceuticals exiting the secondary treatment step. The final part of the review provides an assessment of the environmental risk posed by their presence in the secondary effluent by means of the risk quotient that is the ratio between the average pharmaceutical concentration measured in the secondary effluent and the predicted no-effect concentration. Finally, mass load rankings of the compounds under review are compared with those based on their risk level. This analysis shows that the highest amounts discharged through secondary effluent pertain to one antihypertensive, and several beta-blockers and analgesics/anti-inflammatories, while the highest risk is posed by antibiotics and several psychiatric drugs and analgesics/anti-inflammatories. These results are reported with a view to aiding scientists and administrators in planning measures aiming to reduce the impact of treated urban wastewater discharge into surface water bodies. - Highlights: ► The review refers to 118 pharmaceuticals occurring in raw and treated wastewaters. ► Data from 264 municipal WWTPs with a CAS or an MBR were analysed. ► The removal rates achieved

Occurrence of pharmaceutical compounds in urban wastewater: Removal, mass load and environmental risk after a secondary treatment-A review

Energy Technology Data Exchange (ETDEWEB)

Verlicchi, P., E-mail: paola.verlicchi@unife.it [Dept. of Engineering, University of Ferrara, Via Saragat 1, I-44122 Ferrara (Italy); Terra and AcquaTech Technopoles, Via Borsari 46, I-44121 Ferrara (Italy); Al Aukidy, M., E-mail: mustafakether.alaukidi@unife.it [Dept. of Engineering, University of Ferrara, Via Saragat 1, I-44122 Ferrara (Italy); Zambello, E., E-mail: elena.zambello@unife.it [Dept. of Engineering, University of Ferrara, Via Saragat 1, I-44122 Ferrara (Italy); Terra and AcquaTech Technopoles, Via Borsari 46, I-44121 Ferrara (Italy)

2012-07-01

This review focuses on 118 pharmaceuticals, belonging to seventeen different therapeutic classes, detected in raw urban wastewater and effluent from an activated sludge system, a usual treatment adopted for urban wastewaters worldwide prior to final discharge into surface water bodies. Data pertaining to 244 conventional activated sludge systems and 20 membrane biological reactors are analysed and the observed ranges of variability of each selected compound in their influent and effluent reported, with particular reference to the substances detected most frequently and in higher concentrations. A snapshot of the ability of these systems to remove such compounds is provided by comparing their global removal efficiencies for each substance. Where possible, the study then evaluates the average daily mass load of the majority of detected pharmaceuticals exiting the secondary treatment step. The final part of the review provides an assessment of the environmental risk posed by their presence in the secondary effluent by means of the risk quotient that is the ratio between the average pharmaceutical concentration measured in the secondary effluent and the predicted no-effect concentration. Finally, mass load rankings of the compounds under review are compared with those based on their risk level. This analysis shows that the highest amounts discharged through secondary effluent pertain to one antihypertensive, and several beta-blockers and analgesics/anti-inflammatories, while the highest risk is posed by antibiotics and several psychiatric drugs and analgesics/anti-inflammatories. These results are reported with a view to aiding scientists and administrators in planning measures aiming to reduce the impact of treated urban wastewater discharge into surface water bodies. - Highlights: Black-Right-Pointing-Pointer The review refers to 118 pharmaceuticals occurring in raw and treated wastewaters. Black-Right-Pointing-Pointer Data from 264 municipal WWTPs with a CAS or an

Novel amino-carboxy-dihydroboranes for neutron capture therapy

International Nuclear Information System (INIS)

Boehmel, T.

1985-01-01

The thesis discusses the following topics: I. Synthesis of boron compounds for the neutron capture therapy which are to meet the following requirements: 1. Low toxicity; 2. High boron content; 3. High enrichment and long retention time in the neoplastic tissue and simultaneous low concentration in blood and normal tissue; 4. Independent cytostatic effects; 5. Functional groups which allow a connection with polymers. II. Presentation of compounds with increased 10 B content. III. Examination of the distribution of boric substances in living organisms by means of a quantitative analysis of the boron content. (orig./PW) [de

Review of fission produce capture measurements at the Oak Ridge Electron Laser Accelerator (ORELA)

International Nuclear Information System (INIS)

Larson, D.C.; Macklin, R.L.

1992-01-01

The 40-meter capture system of R.L. Macklin at ORELA has been used to measure capture cross sections for over eighty isotopes between A = 75 and 161, the primary mass region of interest for fission products. This review outlines the primary features of the capture system, lists the isotopes measured and their references, and describes recent changes incorporated in the capture system

A multiple-dimension liquid chromatography coupled with mass spectrometry data strategy for the rapid discovery and identification of unknown compounds from a Chinese herbal formula (Er-xian decoction).

Science.gov (United States)

Wang, Caihong; Zhang, Jinlan; Wu, Caisheng; Wang, Zhe

2017-10-06

It is very important to rapidly discover and identify the multiple components of traditional Chinese medicine (TCM) formula. High performance liquid chromatography with high resolution tandem mass spectrometry (HPLC-HRMS/MS) has been widely used to analyze TCM formula and contains multiple-dimension data including retention time (RT), high resolution mass (HRMS), multiple-stage mass spectrometric (MS n ), and isotope intensity distribution (IID) data. So it is very necessary to exploit a useful strategy to utilize multiple-dimension data to rapidly probe structural information and identify chemical compounds. In this study, a new strategy to initiatively use the multiple-dimension LC-MS data has been developed to discover and identify unknown compounds of TCM in many styles. The strategy guarantees the fast discovery of candidate structural information and provides efficient structure clues for identification. The strategy contains four steps in sequence: (1) to discover potential compounds and obtain sub-structure information by the mass spectral tree similarity filter (MTSF) technique, based on HRMS and MS n data; (2) to classify potential compounds into known chemical classes by discriminant analysis (DA) on the basis of RT and HRMS data; (3) to hit the candidate structural information of compounds by intersection sub-structure between MTSF and DA (M,D-INSS); (4) to annotate and confirm candidate structures by IID data. This strategy allowed for the high exclusion efficiency (greater than 41%) of irrelevant ions in er-xian decoction (EXD) while providing accurate structural information of 553 potential compounds and identifying 66 candidates, therefore accelerating and simplifying the discovery and identification of unknown compounds in TCM formula. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of wetting layer wave functions on carrier capture in quantum dots

DEFF Research Database (Denmark)

Markussen, Troels; Kristensen, Philip; Tromborg, Bjarne

2005-01-01

This work numerically solves the effective mass Schrodinger equation and shows that the capture times are strongly influenced by details of the continuum states not accounted for by the approximate wave functions. Results show that calculations of capture time for phonon mediated carrier capture...... from a wetting layer into a quantum dot depend critically on the approximations used for the wetting layer wave functions....

On Z-dependence of probability of atomic capture of mesons in matter

International Nuclear Information System (INIS)

Vasil'ev, V.A.; Petrukhin, V.I.; Suvorov, V.M.; Khorvat, D.

1976-01-01

All experimental data available on the atomic capture of negative muons and pions are systematically studied to find more appropriate empirical expression for the capture probability as a function of the atomic number. It is shown that Z-dependence, as a rule, does not hold. Zsup(1/3)-dependence gives more satisfactory results. A modified Zsup(1/3-dependence is proposed which is more appropriate for hydrogen - containing compounds

Development of iodine based impinger solutions for the efficient capture of Hg{sup 0} using direct injection nebulization-inductively coupled plasma mass spectrometry analysis

Energy Technology Data Exchange (ETDEWEB)

Hedrick, E.; Lee, T.G.; Biswas, P.; Zhuang, Y. [US Environmental Protection Agency, Cincinnati, OH (USA). National Exposure Research Laboratory

2001-09-15

Inductively coupled plasma mass spectrometry (ICP/MS) with direct injection nebulization (DIN) was used to evaluate novel impinger solution compositions capable of capturing elemental mercury (Hg{sup 0}) in EPA Method 5 type sampling. An iodine based impinger solution proved to be very efficient for Hg{sup 0} capture and was amenable to direct analysis by DIN-ICP/MS. Hg{sup 0} capture efficiency using aqueous iodine (I{sub 3}{sup -}) was comparable to Hg{sup 0} capture using acidified potassium permanganate impinger solutions which were analyzed by cold vapor atomic absorption spectrometry (CVAAS) with greater than 98% capture of Hg{sup 0} in the oxidizing impinger. Using DIN-ICP/MS, it was demonstrated for the first time that iodine can be generated just prior to impinger sampling for efficiently oxidizing Hg{sup 0} and retailing it in solution as HgI{sub 4}{sup 2-}. Due to the increased interest in Hg speciation from combustion sources and the potential for using DIN-ICP/MS for multiple metals analyses, an impinger sampling train for gaseous Hg speciation and multiple metals analyses using DIN-ICP/MS analyses is presented. The unique feature of such a sampling train is that each impinger solution in the series is amenable to direct analysis by DIN-ICP/MS. A bituminous coal was combusted in a bench scale coal system, and gaseous Hg species (oxidized and elemental) were determined using the proposed impinger train. The DIN-ICP/Ms instrumental detection limit was 0.003 ppb, and MDLs ranged from 0.007 to 0.116 {mu}g/L (ppb) in a variety of impinger solutions used for Hg capture. 33 refs., 5 figs., 7 tabs.

Determination of C10-chloroalkane residues in fish matrices by short column gas chromatography/electron capture negative ion low resolution mass spectrometry applying single pure and representative synthesised chlorodecanes as standards

International Nuclear Information System (INIS)

Beaume, Florence; Coelhan, Mehmet; Parlar, Harun

2006-01-01

A new chlorodecane (CD) standard was developed consisting of five single compounds with 5-9 Cl-atoms, with which it was possible to determine chlorodecane residues in fish matrices from different countries using short column gas chromatography/electron capture negative ion low resolution mass spectrometry (SCGC/ECNI-LRMS). The concentrations found were between 4.8 and 30.2 ng/g fat. Pentachlorodecanes could not be detected in all samples. For an evaluation of the new CD-standard, the fish matrices were also quantified by several other polychlorinated decane (CP10) standards with different chlorine grade: 50, 55, 63.5, 65, and 70%. The concentrations found differed unsurprisingly considerable among the applied standards. Considering only these CP10:50-70% standards that showed the highest similarity in peak patterns with the fish samples, the differences in observed chlorodecane concentrations between these standards and the new CD-standard were low, varying only 1-16%. The CP10:50-70% standards were further quantified with the new CD-standard (chlorine content, 58.2%) with neglectable observed differences to the CP10:60, 63.5, and 65% standards. Highest differences were observed to the CP10:50, 55, and 70% standards. By this work, the quantification of eco-toxicologically relevant C10-chloroparaffins using the new CD-standard has led to reproducible and reliable results, which indicates further that these compounds are still a concerning class of substances in environmental fish samples

The electron capture in 163Ho experiment - ECHo

Science.gov (United States)

Gastaldo, L.; Blaum, K.; Chrysalidis, K.; Day Goodacre, T.; Domula, A.; Door, M.; Dorrer, H.; Düllmann, Ch. E.; Eberhardt, K.; Eliseev, S.; Enss, C.; Faessler, A.; Filianin, P.; Fleischmann, A.; Fonnesu, D.; Gamer, L.; Haas, R.; Hassel, C.; Hengstler, D.; Jochum, J.; Johnston, K.; Kebschull, U.; Kempf, S.; Kieck, T.; Köster, U.; Lahiri, S.; Maiti, M.; Mantegazzini, F.; Marsh, B.; Neroutsos, P.; Novikov, Yu. N.; Ranitzsch, P. C. O.; Rothe, S.; Rischka, A.; Saenz, A.; Sander, O.; Schneider, F.; Scholl, S.; Schüssler, R. X.; Schweiger, Ch.; Simkovic, F.; Stora, T.; Szücs, Z.; Türler, A.; Veinhard, M.; Weber, M.; Wegner, M.; Wendt, K.; Zuber, K.

2017-06-01

Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak interactions, in particular of the 3H β-decay and the 163Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in 163Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide 163Ho. The maximum energy available for this decay, about 2.8 keV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the 163Ho EC spectrum with energy resolution below 3 eV FWHM and with a time resolution below 1 μs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure 163Ho samples, the identification and suppression of background sources as well as the precise parametrization of the 163Ho EC spectrum are of utmost importance. The high-energy resolution 163Ho spectra measured with the first MMC prototypes with ion-implanted 163Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1 kBq 163Ho will allow to reach a neutrino mass sensitivity below 10 eV/ c 2. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1 MBq 163Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass.

Simulation of mercury capture by sorbent injection using a simplified model.

Science.gov (United States)

Zhao, Bingtao; Zhang, Zhongxiao; Jin, Jing; Pan, Wei-Ping

2009-10-30

Mercury pollution by fossil fuel combustion or solid waste incineration is becoming the worldwide environmental concern. As an effective control technology, powdered sorbent injection (PSI) has been successfully used for mercury capture from flue gas with advantages of low cost and easy operation. In order to predict the mercury capture efficiency for PSI more conveniently, a simplified model, which is based on the theory of mass transfer, isothermal adsorption and mass balance, is developed in this paper. The comparisons between theoretical results of this model and experimental results by Meserole et al. [F.B. Meserole, R. Chang, T.R. Carrey, J. Machac, C.F.J. Richardson, Modeling mercury removal by sorbent injection, J. Air Waste Manage. Assoc. 49 (1999) 694-704] demonstrate that the simplified model is able to provide good predictive accuracy. Moreover, the effects of key parameters including the mass transfer coefficient, sorbent concentration, sorbent physical property and sorbent adsorption capacity on mercury adsorption efficiency are compared and evaluated. Finally, the sensitive analysis of impact factor indicates that the injected sorbent concentration plays most important role for mercury capture efficiency.

Theory of inelastic multiphonon scattering and carrier capture by defects in semiconductors: Application to capture cross sections

Science.gov (United States)

Barmparis, Georgios D.; Puzyrev, Yevgeniy S.; Zhang, X.-G.; Pantelides, Sokrates T.

2015-12-01

Inelastic scattering and carrier capture by defects in semiconductors are the primary causes of hot-electron-mediated degradation of power devices, which holds up their commercial development. At the same time, carrier capture is a major issue in the performance of solar cells and light-emitting diodes. A theory of nonradiative (multiphonon) inelastic scattering by defects, however, is nonexistent, while the theory for carrier capture by defects has had a long and arduous history. Here we report the construction of a comprehensive theory of inelastic scattering by defects, with carrier capture being a special case. We distinguish between capture under thermal equilibrium conditions and capture under nonequilibrium conditions, e.g., in the presence of an electrical current or hot carriers where carriers undergo scattering by defects and are described by a mean free path. In the thermal-equilibrium case, capture is mediated by a nonadiabatic perturbation Hamiltonian, originally identified by Huang and Rhys and by Kubo, which is equal to linear electron-phonon coupling to first order. In the nonequilibrium case, we demonstrate that the primary capture mechanism is within the Born-Oppenheimer approximation (adiabatic transitions), with coupling to the defect potential inducing Franck-Condon electronic transitions, followed by multiphonon dissipation of the transition energy, while the nonadiabatic terms are of secondary importance (they scale with the inverse of the mass of typical atoms in the defect complex). We report first-principles density-functional-theory calculations of the capture cross section for a prototype defect using the projector-augmented wave, which allows us to employ all-electron wave functions. We adopt a Monte Carlo scheme to sample multiphonon configurations and obtain converged results. The theory and the results represent a foundation upon which to build engineering-level models for hot-electron degradation of power devices and the performance

Selected Ion Flow Tube-Mass Spectrometry for Absolute Quantification of Aroma Compounds in the Headspace of Dry Fermented Sausages

Czech Academy of Sciences Publication Activity Database

Olivares, A.; Dryahina, Kseniya; Navarro, J. L.; Flores, M.; Smith, D.; Španěl, Patrik

2010-01-01

Roč. 82, č. 13 (2010), s. 5819-5829 ISSN 0003-2700 R&D Projects: GA ČR GA203/09/0256 Institutional research plan: CEZ:AV0Z40400503 Keywords : mass spectrometry * aroma compounds * dry fermented sausages Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.874, year: 2010

Determination of Endocrine Disrupting Compounds in surface waters by means of chromatographic techniques coupled to mass spectrometry

Directory of Open Access Journals (Sweden)

M. Di Carro

2011-01-01

Full Text Available Two analytical methods were developed to study five endocrine disrupting compounds (4-n-nonylphenol, bisphenol A, estrone, 17β-estradiol and 17α-ethinylestradiol in waters. One method includes a fast liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS analysis, while the second comprise a Stir Bar Sorptive Extraction (SBSE followed by a headspace derivatization and gaschromatography-mass spectrometry (GC-MS analysis. Passive samplers POCIS (Polar Organic Chemical Integrative Samplers were used as sampling and preconcentration steps in order to reach the very low levels of the analytes in environmental waters. Both methods were then applied to the determination of the analytes in different water samples.

Byproduct-free mass production of compound semiconductor nanowires: zinc phosphide

Science.gov (United States)

Chen, Yixi; Polinnaya, Rakesh; Vaddiraju, Sreeram

2018-05-01

A method for the mass production of compound semiconductor nanowires that involves the direct reaction of component elements in a chemical vapor deposition chamber (CVD) is presented. This method results in nanowires, without the associated production of any other byproducts such as nanoparticles or three-dimensional (3D) bulk crystals. Furthermore, no unreacted reactants remain mixed with the nanowire product in this method. This byproduct-free nanowire production thus circumvents the need to tediously purify and collect nanowires from a mixture of products/reactants after their synthesis. Demonstration made using zinc phosphide (Zn3P2) material system as an example indicated that the direct reaction of zinc microparticles with phosphorus supplied via the vapor phase results in the production of gram quantities of nanowires. To enhance thermal transport and achieve the complete reaction of zinc microparticles, while simultaneously ensuring that the microparticles do not agglomerate into macroscale zinc particles and partly remain unreacted (owing to diffusion limitations), pellets composed of mixtures of zinc and a sacrificial salt, NH4Cl, were employed as the starting material. The sublimation by decomposition of NH4Cl in the early stages of the reaction leaves a highly porous pellet of zinc composed of only zinc microparticles, which allows for inward diffusion of phosphorus/outward diffusion of zinc and the complete conversion of zinc into Zn3P2 nanowires. NH4Cl also aids in removal of any native oxide layer present on the zinc microparticles that may prevent their reaction with phosphorus. This method may be used to mass produce many other nanowires in a byproduct-free manner, besides Zn3P2.

Mass spectrometrical study of rare gas compositions and neutron capture effects in Yamato-74191 (L 3) Chondrite

International Nuclear Information System (INIS)

Takaoka, N.; Nagao, K.

1980-01-01

The unequilibrated hypersthene chondrite Yamato-74191 was studied mass spectrometrically for rare gases released at various temperatures. Cosmogenic gases dominate in He and Ne. The meteorite contains large amounts of trapped Ar, Kr and Xe, and radiogenic 40 Ar and 129 Xe. Cosmic-ray irradiation and K-Ar ages were determined. In addition to spallogenic components of Kr and Xe, isotopic excesses of 8 sup(O)Kr, 82 Kr, 128 Xe and 126 Xe relative to AVCC-Kr and -Xe were found. The ratio of 80 Kr-excess to 82 Kr-excess is 2.66 after correction for spallogenic Kr. A correlation between 128 Xe/ 132 Xe and 129 Xe/ 132 Xe was found. The 129 Xe/ 132 Xe ratio for trapped Xe in Yamato-74191 was determined as 1.12 +- 0.29 with the correlation plot. The excesses found in Yamato-74191 are best explained by epithermal neutron capture on Br and I, and by the 127 I(n,2nβ) 126 Xe reaction. Using neutron-produced 80 Kr, the neutron slowing-down density was estimated to be 0.14 +- 0.03 cm -3 sec -1 . A minimum mass and a preatmospheric radius was estimated to be 470 kg and 32 cm, respectively. (orig.)

Development Research of new boron-compounds for boron neutron capture therapy. Biological activity evaluation of amino group in p-boronophenylalanine and p-boronophenylalaninol

International Nuclear Information System (INIS)

Kumanisi, A.; Uehara, K.; Takikawa, S.; Kirihata, M.; Takagaki, M.; Ono, K.; Sakurai, Y.; Kobayashi, T.

2001-01-01

Para-boronophenylalanine (BPA) is used as a leading compound for development and research of some of new boron carriers for boron neutron capture therapy. Para-boronophenylalaninol (BPA-ol) is designed molecularly by converting carboxyl group of the BPA to hydroxyl group. The BPA-ol gets a good result in biological test in-vitro and in-vivo. N-methyl-BPA and N-methyl-BPA-ol are synthesized for biological activity evaluation of amino group in the BPA. Two pathways for methylation of amino group in the BPA are investigated. These synthesized compounds of N-methyl-BPA, N-methyl-BPA-ol, and the BPA-ol are tested by colony formation method using gliosarcoma C6 cultured cells of rats. Absorbed doses (thermal neutron fluences) corresponding to the 10% surviving fraction are 1.69 x 10 13 for N-methyl-BPA, 1.13 x 10 13 for N-methyl-BPA-ol, and 6.87 x 10 12 for BPA-ol, respectively. Toxicity of N-methyl-BPA or N-Methyl-BPA-ol to the cultured cells is below that of the BPA. The toxicity of N-methyl-BPA-ol, particularly, is less than 1/100 of that of the BPA. (M. Suetake)

Non-targeted acquisition strategy for screening doping compounds based on GC-EI-hybrid quadrupole-Orbitrap mass spectrometry: A focus on exogenous anabolic steroids.

Science.gov (United States)

de Albuquerque Cavalcanti, Gustavo; Rodrigues, Lucas Martins; Dos Santos, Leonardo; Zheng, Xin; Gujar, Amit; Cole, Jason; Padilha, Monica Costa; de Aquino Neto, Francisco Radler

2018-03-01

This is a first look at a non-targeted screening method based on Orbitrap gas chromatography-mass spectrometry (GC-MS) technology for a large number of banned compounds in sports found in urine, including exogenous anabolic steroids, β-agonists, narcotics, stimulants, hormone modulators, and diuretics. A simple sample preparation was processed in four steps: an enzymatic hydrolysis, liquid-liquid extraction, evaporation, and trimethylsilylation. All compounds were able to meet the World Anti-Doping Agency's sensitivity criteria with mass accuracies less than 1 ppm and with sufficient points across the peak by running the Orbitrap GC-MS in full-scan mode. In addition, we discuss our initial findings of using a full-scan selected ion monitoring-tandem mass spectrometry (SIM-MS/MS) approach as a way to obtain lower detection limits and reach desirable selectivity for some exogenous anabolic steroids. Copyright © 2017 John Wiley & Sons, Ltd.

Real-time analysis of organic compounds in ship engine aerosol emissions using resonance-enhanced multiphoton ionisation and proton transfer mass spectrometry.

Science.gov (United States)

Radischat, Christian; Sippula, Olli; Stengel, Benjamin; Klingbeil, Sophie; Sklorz, Martin; Rabe, Rom; Streibel, Thorsten; Harndorf, Horst; Zimmermann, Ralf

2015-08-01

Organic combustion aerosols from a marine medium-speed diesel engine, capable to run on distillate (diesel fuel) and residual fuels (heavy fuel oil), were investigated under various operating conditions and engine parameters. The online chemical characterisation of the organic components was conducted using a resonance-enhanced multiphoton ionisation time-of-flight mass spectrometer (REMPI TOF MS) and a proton transfer reaction-quadrupole mass spectrometer (PTR-QMS). Oxygenated species, alkenes and aromatic hydrocarbons were characterised. Especially the aromatic hydrocarbons and their alkylated derivatives were very prominent in the exhaust of both fuels. Emission factors of known health-hazardous compounds (e.g. mono- and poly-aromatic hydrocarbons) were calculated and found in higher amounts for heavy fuel oil (HFO) at typical engine loadings. Lower engine loads lead in general to increasing emissions for both fuels for almost every compound, e.g. naphthalene emissions varied for diesel fuel exhaust between 0.7 mg/kWh (75 % engine load, late start of injection (SOI)) and 11.8 mg/kWh (10 % engine load, late SOI) and for HFO exhaust between 3.3 and 60.5 mg/kWh, respectively. Both used mass spectrometric techniques showed that they are particularly suitable methods for online monitoring of combustion compounds and very helpful for the characterisation of health-relevant substances. Graphical abstract Three-dimensional REMPI data of organic species in diesel fuel and heavy fuel oil exhaust.

Automated Online Solid-Phase Derivatization for Sensitive Quantification of Endogenous S-Nitrosoglutathione and Rapid Capture of Other Low-Molecular-Mass S-Nitrosothiols.

Science.gov (United States)

Wang, Xin; Garcia, Carlos T; Gong, Guanyu; Wishnok, John S; Tannenbaum, Steven R

2018-02-06

S-Nitrosothiols (RSNOs) constitute a circulating endogenous reservoir of nitric oxide and have important biological activities. In this study, an online coupling of solid-phase derivatization (SPD) with liquid chromatography-mass spectrometry (LC-MS) was developed and applied in the analysis of low-molecular-mass RSNOs. A derivatizing-reagent-modified polymer monolithic column was prepared and adapted for online SPD-LC-MS. Analytes from the LC autosampler flowed through the monolithic column for derivatization and then directly into the LC-MS for analysis. This integration of the online derivatization, LC separation, and MS detection facilitated system automation, allowing rapid, laborsaving, and sensitive detection of RSNOs. S-Nitrosoglutathione (GSNO) was quantified using this automated online method with good linearity (R 2 = 0.9994); the limit of detection was 0.015 nM. The online SPD-LC-MS method has been used to determine GSNO levels in mouse samples, 138 ± 13.2 nM of endogenous GSNO was detected in mouse plasma. Besides, the GSNO concentrations in liver (64.8 ± 11.3 pmol/mg protein), kidney (47.2 ± 6.1 pmol/mg protein), heart (8.9 ± 1.8 pmol/mg protein), muscle (1.9 ± 0.3 pmol/mg protein), hippocampus (5.3 ± 0.9 pmol/mg protein), striatum (6.7 ± 0.6 pmol/mg protein), cerebellum (31.4 ± 6.5 pmol/mg protein), and cortex (47.9 ± 4.6 pmol/mg protein) were also successfully quantified. When the derivatization was performed within 8 min, followed by LC-MS detection, samples could be rapidly analyzed compared with the offline manual method. Other low-molecular-mass RSNOs, such as S-nitrosocysteine and S-nitrosocysteinylglycine, were captured by rapid precursor-ion scanning, showing that the proposed method is a potentially powerful tool for capture, identification, and quantification of RSNOs in biological samples.

Super-AGB Stars and their Role as Electron Capture Supernova Progenitors

Science.gov (United States)

Doherty, Carolyn L.; Gil-Pons, Pilar; Siess, Lionel; Lattanzio, John C.

2017-11-01

We review the lives, deaths and nucleosynthetic signatures of intermediate-mass stars in the range ≈6-12 M⊙, which form super-AGB stars near the end of their lives. The critical mass boundaries both between different types of massive white dwarfs (CO, CO-Ne, ONe), and between white dwarfs and supernovae, are examined along with the relative fraction of super-AGB stars that end life either as an ONe white dwarf or as a neutron star (or an ONeFe white dwarf), after undergoing an electron capture supernova event. The contribution of the other potential single-star channel to electron-capture supernovae, that of the failed massive stars, is also discussed. The factors that influence these different final fates and mass limits, such as composition, rotation, the efficiency of convection, the nuclear reaction rates, mass-loss rates, and third dredge-up efficiency, are described. We stress the importance of the binary evolution channels for producing electron-capture supernovae. Recent nucleosynthesis calculations and elemental yield results are discussed and a new set of s-process heavy element yields is presented. The contribution of super-AGB star nucleosynthesis is assessed within a Galactic perspective, and the (super-)AGB scenario is considered in the context of the multiple stellar populations seen in globular clusters. A brief summary of recent works on dust production is included. Last, we conclude with a discussion of the observational constraints and potential future advances for study into these stars on the low mass/high mass star boundary.

Coumarins as new matrices for matrix-assisted laser-desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric analysis of hydrophobic compounds

Energy Technology Data Exchange (ETDEWEB)

Wang, Hang, E-mail: hangwang@sjtu.edu.cn [Instrumental Analysis Center, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Dai, Bona [Instrumental Analysis Center, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China); Liu, Bin [Key Laboratory of Kidney Disease Pathogenesis and Intervention of Hubei Province, College of Medicine, Hubei Polytechnic University, Huangshi, Hubei 435003 (China); Lu, Han [Department of Anesthesiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine (SJTU-SM), 197, Rui Jin Er Road, Shanghai 200025 (China)

2015-07-02

Highlights: • Coumarins were used as new MALDI matrices. • Coumarins were used for MALDI-FT ICR MS detection of hydrophobic compounds. • DCA had improvement in detection sensitivity, stability, selectivity and reproducibility. • DCA was applied to sterols detection in yeast cells. - Abstract: Hydrophobic compounds with hydroxyl, aldehyde or ketone groups are generally difficult to detect using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), because these compounds have low proton affinity and are poorly ionized by MALDI. Herein, coumarins have been used as new matrices for MALDI-MS analysis of a variety of hydrophobic compounds with low ionization efficiency, including steroids, coenzyme Q10, a cyclic lipopeptide and cholesterol oleate. Five coumarins, including coumarin, umbelliferone, esculetin, 7-hydroxycoumarin-3-carboxylic acid (HCA) and 6,7-dihydroxycoumarin-3-carboxylic acid (DCA), were compared with the conventional matrices of 2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (CHCA). Coumarins with hydroxyl or carboxylic acid groups enabled detection. Taking DCA as an example, this matrix proved to be superior to DHB or CHCA in detection sensitivity, stability, spot-to-spot and sample-to-sample reproducibility, and accuracy. DCA increased the stability of the target compounds and decreased the loss of water. The [M + Na]{sup +} peaks were observed for all target compounds by adding NaCl as an additive, and the [M − H{sub 2}O + H]{sup +} and [M + H]{sup +} peaks decreased. DCA was selected for the identification of sterols in yeast cells, and thirteen sterols were detected by Fourier transform ion cyclotron resonance (FT ICR) mass spectrometry. This work demonstrates the potential of DCA as a new matrix for detection of hydrophobic molecules by MALDI-MS and provides an alternative tool for screening sterols in antifungal research.

Experimental Neutron Capture Rate Constraint Far from Stability.

Science.gov (United States)

Liddick, S N; Spyrou, A; Crider, B P; Naqvi, F; Larsen, A C; Guttormsen, M; Mumpower, M; Surman, R; Perdikakis, G; Bleuel, D L; Couture, A; Crespo Campo, L; Dombos, A C; Lewis, R; Mosby, S; Nikas, S; Prokop, C J; Renstrom, T; Rubio, B; Siem, S; Quinn, S J

2016-06-17

Nuclear reactions where an exotic nucleus captures a neutron are critical for a wide variety of applications, from energy production and national security, to astrophysical processes, and nucleosynthesis. Neutron capture rates are well constrained near stable isotopes where experimental data are available; however, moving far from the valley of stability, uncertainties grow by orders of magnitude. This is due to the complete lack of experimental constraints, as the direct measurement of a neutron-capture reaction on a short-lived nucleus is extremely challenging. Here, we report on the first experimental extraction of a neutron capture reaction rate on ^{69}Ni, a nucleus that is five neutrons away from the last stable isotope of Ni. The implications of this measurement on nucleosynthesis around mass 70 are discussed, and the impact of similar future measurements on the understanding of the origin of the heavy elements in the cosmos is presented.

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

Science.gov (United States)

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

1999-06-04

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

Considerations for boron neutron capture therapy studies

International Nuclear Information System (INIS)

Faria Gaspar, P. de.

1994-01-01

Radiotherapy is indispensable as a mean to eradicate deeply or infiltrating tumor tissue that can not be removed surgically. Therefore, it is not selective and may also kill the surrounding health tissue. The principle of BNCT (Boron Neutron Capture Therapy) consist in targeting a tumor selectively with a boron-10 compound. This nuclide has a large capture cross section for thermal neutrons and the nuclear reaction and the delivered energy in locus will selective the tumor. Since its initial proposal in 1963 BNCT has made much progress, however it is not used in a routine treatment. In this work it was approached some complex procedures, as the obtention of selective boron compounds, the adequate set up of neutron beams, the biodistribution, the in vivo and in vitro studies, and also human patients treatments. This work provide fundamentals about BNCT to professional of different areas of knowledge since it comprises multidisciplinary study. It includes appendixes for the ones not related to the field for a better comprehension of the many aspects involved. It is also presented a glossary containing technical and basic aspects involved. It is also presented a glossary containing technical and basic terms referred in the work. (author). 174 refs, 1 fig, 12 apps

Technology Roadmap: Carbon Capture and Storage

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-01

As long as fossil fuels and carbon-intensive industries play dominant roles in our economies, carbon capture and storage (CCS) will remain a critical greenhouse gas reduction solution. This CCS roadmap aims at assisting governments and industry in integrating CCS in their emissions reduction strategies and in creating the conditions for scaled-up deployment of all three components of the CCS chain: CO2 capture, transport and storage. To get us onto the right pathway, this roadmap highlights seven key actions needed in the next seven years to create a solid foundation for deployment of CCS starting by 2020. IEA analysis shows that CCS is an integral part of any lowest-cost mitigation scenario where long-term global average temperature increases are limited to significantly less than 4 °C, particularly for 2 °C scenarios (2DS). In the 2DS, CCS is widely deployed in both power generation and industrial applications. The total CO2 capture and storage rate must grow from the tens of megatonnes of CO2 captured in 2013 to thousands of megatonnes of CO2 in 2050 in order to address the emissions reduction challenge. A total cumulative mass of approximately 120 GtCO2 would need to be captured and stored between 2015 and 2050, across all regions of the globe.

Film mass transfer coefficient for the prediction of volatile organic compound evaporation rate from open water basin

OpenAIRE

Charun Bunyakan; Preyaporn Tongsoi; Chakrit Tongurai

2001-01-01

The evaporation of volatile organic compounds(VOCs) from treatment, storage, disposal facility(TSDF) is an important air pollution issue because of the evaporation quantity and toxicity and/or carcinogenicity. This paper concerns VOC evaporation from open water basins such as the equalization basin and nonaerate surface impoundments in a wastewater treatment plant. The amount of VOCs evaporation from open water basins can be predicted by using the two-film model that requires two mass transfe...

Arsenic compounds in a marine food chain

Energy Technology Data Exchange (ETDEWEB)

Goessler, W.; Irgolic, K.J.; Kuehnelt, D.; Schlagenhaufen, C. [Institute for Analytical Chemistry, Karl-Franzens-Universitaet Graz, Universitaetsplatz 1, A-8010 Graz (Austria); Maher, W. [CRC for Freshwater Ecology, University of Canberra, PO Box 1, Belconnen ACT. 2616 (Australia); Kaise, T. [Laboratory of Environmental Chemistry, School of Life Science, University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachijoji, Tokyo 192-03 (Japan)

1997-10-01

A three-organism food chain within a rock pool at Rosedale, NSW, Australia, was investigated with respect to arsenic compounds by high performance liquid chromatography - hydraulic high pressure nebulization - inductively coupled plasma mass spectrometry (HPLC-HHPN-ICP-MS). Total arsenic concentration was determined in the seaweed Hormosira banksii (27.2 {mu}g/g dry mass), in the gastropod Austrocochlea constricta (74.4 {mu}g/g dry mass), which consumes the seaweed, and in the gastropod Morula marginalba (233 {mu}g/g dry mass), which eats Austrocochlea constricta. The major arsenic compounds in the seaweed were (2`R)-dimethyl[1-O-(2`,3`-dihydroxypropyl)-5-deoxy-{beta}-d-ribofuranos-5-yl]arsine oxide and an unidentified compound. The herbivorous gastropod Austrocochlea constricta transformed most of the arsenic taken up with the seaweed to arsenobetaine. Traces of arsenite, arsenate, dimethylarsinic acid, arsenocholine, the tetramethylarsonium cation, and several unknown arsenic compounds were detected. Arsenobetaine accounted for 95% of the arsenic in the carnivorous gastropod Morula marginalba. In Morula marginalba the concentration of arsenocholine was higher, and the concentrations of the minor arsenic compounds lower than in the herbivorous gastropod Austrocochlea constricta. (orig.) With 4 figs., 1 tab., 13 refs.

Compounds enhanced in a mass spectrometric profile of smokers' exhaled breath versus non-smokers as determined in a pilot study using PTR-MS.

Science.gov (United States)

Kushch, Ievgeniia; Schwarz, Konrad; Schwentner, Lukas; Baumann, Bettina; Dzien, Alexander; Schmid, Alex; Unterkofler, Karl; Gastl, Günter; Spaněl, Patrik; Smith, David; Amann, Anton

2008-06-01

A pilot study has been carried out to define typical characteristics of the trace gas compounds in exhaled breath of non-smokers and smokers to assist interpretation of breath analysis data from patients who smoke with respiratory diseases and lung cancer. Exhaled breath was analyzed using proton transfer reaction-mass spectrometry (PTR-MS) for 370 volunteers (81 smokers, 210 non-smokers, 79 ex-smokers). Volatile organic compounds corresponding to product ions at seven mass-to-charge ratios (m/z 28, 42, 69, 79, 93, 97, 123) in the PTR-MS spectra differentiated between smokers and non-smokers. The Youden index (= maximum of sensitivity + specificity - 1, YI) as a measure for differentiation between smokers and non-smokers was YI = 0.43 for ions at the m/z values 28 (tentatively identified as HCN), YI = 0.75 for m/z = 42 (tentatively identified as acetonitrile) and YI = 0.53 for m/z = 79 (tentatively identified as benzene). No statistically significant difference between smokers and non-smokers was observed for the product ions at m/z = 31 and 33 (compounds tentatively identified as formaldehyde and methanol). When interpreting the exhaled breath of lung cancer or COPD patients, who often smoke, compounds appearing at the above-mentioned seven mass-to-charge ratios should be considered with appropriate care to avoid misdiagnosis. Validation studies in larger numbers of patients with more precise delineation of their smoking behavior and using additional analytical techniques such as GC/MS and SIFT-MS should be carried out.

3D CAPTURING PERFORMANCES OF LOW-COST RANGE SENSORS FOR MASS-MARKET APPLICATIONS

Directory of Open Access Journals (Sweden)

G. Guidi

2016-06-01

Full Text Available Since the advent of the first Kinect as motion controller device for the Microsoft XBOX platform (November 2010, several similar active and low-cost range sensing devices have been introduced on the mass-market for several purposes, including gesture based interfaces, 3D multimedia interaction, robot navigation, finger tracking, 3D body scanning for garment design and proximity sensors for automotive. However, given their capability to generate a real time stream of range images, these has been used in some projects also as general purpose range devices, with performances that for some applications might be satisfying. This paper shows the working principle of the various devices, analyzing them in terms of systematic errors and random errors for exploring the applicability of them in standard 3D capturing problems. Five actual devices have been tested featuring three different technologies: i Kinect V1 by Microsoft, Structure Sensor by Occipital, and Xtion PRO by ASUS, all based on different implementations of the Primesense sensor; ii F200 by Intel/Creative, implementing the Realsense pattern projection technology; Kinect V2 by Microsoft, equipped with the Canesta TOF Camera. A critical analysis of the results tries first of all to compare them, and secondarily to focus the range of applications for which such devices could actually work as a viable solution.

Precise mass measurements of astrophysical interest made with the Canadian Penning trap mass spectrometer

International Nuclear Information System (INIS)

Clark, J.A.; Barber, R.C.; Blank, B.; Boudreau, C.; Buchinger, F.; Crawford, J.E.; Gulick, S.; Hardy, J.C.; Heinz, A.; Lee, J.K.P.; Levand, A.F.; Moore, R.B.; Savard, G.; Seweryniak, D.; Sharma, K.S.; Sprouse, G.D.; Trimble, W.; Vaz, J.; Wang, J.C.; Zhou, Z.

2004-01-01

The processes responsible for the creation of elements more massive than iron are not well understood. Possible production mechanisms involve the rapid capture of protons (rp-process) or the rapid capture of neutrons (r-process), which are thought to occur in explosive astrophysical events such as novae, x-ray bursts, and supernovae. Mass measurements of the nuclides involved with uncertainties on the order of 100 keV or better are critical to determine the process 'paths', the energy output of the events, and the resulting nuclide abundances. Particularly important are the masses of 'waiting-point' nuclides along the rp-process path where the process stalls until the subsequent β decay of the nuclides. This paper will discuss the precise mass measurements made of isotopes along the rp-process and r-process paths using the Canadian Penning Trap mass spectrometer, including the mass of the critical waiting-point nuclide 68 Se

Simultaneous detection of low and high molecular weight carbonylated compounds derived from lipid peroxidation by electrospray ionization-tandem mass spectrometry.

Science.gov (United States)

Milic, Ivana; Hoffmann, Ralf; Fedorova, Maria

2013-01-02

Reactive oxygen species (ROS) and other oxidative agents such as free radicals can oxidize polyunsaturated fatty acids (PUFA) as well as PUFA in lipids. The oxidation products can undergo consecutive reactions including oxidative cleavages to yield a chemically diverse group of products, such as lipid peroxidation products (LPP). Among them are aldehydes and ketones ("reactive carbonyls") that are strong electrophiles and thus can readily react with nucleophilic side chains of proteins, which can alter the protein structure, function, cellular distribution, and antigenicity. Here, we report a novel technique to specifically derivatize both low molecular and high molecular weight carbonylated LPP with 7-(diethylamino)coumarin-3-carbohydrazide (CHH) and analyze all compounds by electrospray ionization-mass spectrometry (ESI-MS) in positive ion mode. CHH-derivatized compounds were identified by specific neutral losses or fragment ions. The fragment ion spectra displayed additional signals that allowed unambiguous identification of the lipid, fatty acids, cleavage sites, and oxidative modifications. Oxidation of docosahexaenoic (DHA, 22:6), arachidonic (AA, 20:4), linoleic (LA, 18:2), and oleic acids (OA, 18:1) yielded 69 aliphatic carbonyls, whose structures were all deduced from the tandem mass spectra. When four phosphatidylcholine (PC) vesicles containing the aforementioned unsaturated fatty acids were oxidized, we were able to deduce the structures of 122 carbonylated compounds from the tandem mass spectra of a single shotgun analysis acquired within 15 min. The high sensitivity (LOD ∼ 1 nmol/L for 4-hydroxy-2-nonenal, HNE) and a linear range of more than 3 orders of magnitude (10 nmol/L to 10 μmol/L for HNE) will allow further studies on complex biological samples including plasma.

High-throughput screening and quantitation of guanidino and ureido compounds using liquid chromatography-drift tube ion mobility spectrometry-mass spectrometry.

Science.gov (United States)

Fan, Ruo-Jing; Zhang, Fang; Chen, Xiu-Ping; Qi, Wan-Shu; Guan, Qing; Sun, Tuan-Qi; Guo, Yin-Long

2017-04-08

The present work focused on the high-throughput screening and quantitation of guanidino compounds (GCs) and ureido compounds (UCs) in human thyroid tissues. The strategy employed benzylic rearrangement stable isotope labeling (BRSIL) for the sample preparation and then detection using liquid chromatography-drift tube ion mobility spectrometry-quadrupole time of flight mass spectrometry (LC-DTIMS-QTOF MS). A short reversed-phase LC realized an on-line desalting and a measurement cycle of 5.0 min. DTIMS separation enhanced the better specificity and selectivity for the benzil labeled GCs and UCs. The elevated mass resolution of QTOF MS enabled measure of the characteristic ions at accurate mass in MS and tandem MS spectra. Collision cross section (CCS) from DTIMS and accurate mass from QTOF MS were used as two qualifiers for the profiling and identification of GCs and UCs. In addition, an integral abundance arising from 3-D ion features (retention time, drift time, m/z) was applied to quantify the GCs and UCs in human thyroid tissues. The quantitative validation indicated good linearity (coefficient values ≥ 0.9981), good precision (1.0%-12.3% for intra-day and 0.9%-7.8% for inter-day) and good accuracy (91%-109%). The results demonstrated that the developed BRSIL coupled with LC-DTIMS-QTOF MS can be a powerful analysis platform to investigate GCs and UCs in human thyroid tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

Resonance parameters for measured keV neutron capture cross sections

Energy Technology Data Exchange (ETDEWEB)

Musgrove, A.R. de L

1969-05-01

All available neutron capture cross sections in the keV region ({approx} to 100 keV) have been fitted with resonance parameters. Capture cross sections for nuclides with reasonably well known average s-wave parameters, but no measured cross section, have been calculated and tabulated using p-and d- wave strength functions interpolated between fitted values. Several of these nuclides are of interest in the theory of slow nucleosynthesis of heavy elements in stars, and the product of cosmic abundance (due to the s-process) and capture cross section at 30 keV has been plotted versus mass number. (author)

Rapid screening and distribution of bioactive compounds in different parts of Berberis petiolaris using direct analysis in real time mass spectrometry

Directory of Open Access Journals (Sweden)

Awantika Singh

2015-10-01

Full Text Available Berberis petiolaris Wall. ex G. Don, an unexplored medicinal plant belonging to the family Berberidaceae, is a large deciduous shrub found in Western Himalaya between 1800–3000 m. Chemical profiling of fruit, leaf, root and stem was done by direct analysis in real time mass spectrometry followed by multivariate analysis for discrimination among the plant parts. The bioactive compounds, including magnoflorine, berberine, jatrorrhizine, thalifendine/berberrubine, demethyleneberberine, reticuline, 8-oxoberberine, N-methyltetrahydroberberine, tetrahydropalmatine, tetrahydroberberine and palmatine, were identified by their exact mass measurement and the corresponding molecular formula of each compound. A comparative study of distribution pattern for all these bioactive alkaloids showed qualitative and quantitative variations in different parts of B. petiolaris. Principal component analysis clearly discriminated each part of B. petiolaris plant. Keywords: Berberis petiolaris, Alkaloids, Profiling, DART–TOF–MS, Statistical analysis

New carbon-carbon linked amphiphilic carboranyl-porphyrins as boron neutron capture agents

International Nuclear Information System (INIS)

Vicente, M.G.H.; Wickramasinghe, A.; Shetty, S.J.; Smith, K.M.

2000-01-01

Novel amphiphilic carboranyl-porphyrins have been synthesized for Boron Neutron Capture Therapy (BNCT). These compounds have carbon-carbon bonds between the carborane residues and the porphyrin meso-phenyl groups, and contain 28-31% boron by weight . (author)

Rapid profiling of polymeric phenolic acids in Salvia miltiorrhiza by hybrid data-dependent/targeted multistage mass spectrometry acquisition based on expected compounds prediction and fragment ion searching.

Science.gov (United States)

Shen, Yao; Feng, Zijin; Yang, Min; Zhou, Zhe; Han, Sumei; Hou, Jinjun; Li, Zhenwei; Wu, Wanying; Guo, De-An

2018-04-01

Phenolic acids are the major water-soluble components in Salvia miltiorrhiza (>5%). According to previous studies, many of them contribute to the cardiovascular effects and antioxidant effects of S. miltiorrhiza. Polymeric phenolic acids can be considered as the tanshinol derived metabolites, e.g., dimmers, trimers, and tetramers. A strategy combined with tanshinol-based expected compounds prediction, total ion chromatogram filtering, fragment ion searching, and parent list-based multistage mass spectrometry acquisition by linear trap quadropole-orbitrap Velos mass spectrometry was proposed to rapid profile polymeric phenolic acids in S. miltiorrhiza. More than 480 potential polymeric phenolic acids could be screened out by this strategy. Based on the fragment information obtained by parent list-activated data dependent multistage mass spectrometry acquisition, 190 polymeric phenolic acids were characterized by comparing their mass information with literature data, and 18 of them were firstly detected from S. miltiorrhiza. Seven potential compounds were tentatively characterized as new polymeric phenolic acids from S. miltiorrhiza. This strategy facilitates identification of polymeric phenolic acids in complex matrix with both selectivity and sensitivity, which could be expanded for rapid discovery and identification of compounds from complex matrix. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of Mass Spectrometry for the Analysis of Vitellogenin, a Unique Biomarker for Xenobiotic Compounds

Science.gov (United States)

Cohen, Alejandro M.; Banoub, Joseph H.

Vitellogenin is a complex phosphoglycolipoprotein that is secreted into the bloodstream of sexually mature, female, oviparous animals in response to circulating estrogens. It is then incorporated into the ovaries by receptor mediated endocytosis, where it is further cleaved to form the major constituents of the egg yolk proteins. It is generally accepted that these protein and peptide products serve as the main nutritional reserve for the developing embryo. Quantification of vitellogenin in blood is useful for different purposes. The reproductive status and degree of sexual maturation of oviparous animals can be assessed according to the levels of vitellogenin in plasma. The expression of this protein can also be induced in males under the effect of estrogenic compounds. Relying on this observation, vitellogenin has been used as a unique biomarker of environmental endocrine disruption in many species. In this respect, vitellogenin levels could potentially be used to assess the use of chemical warefare compounds with estrogenic activity. In this paper we review a technique developed for measuring vitellogenin plasma levels of different fish species using high performance liquid chromatography coupled to tandem mass spectrometry.

The influence of surfactant on mass transfer coefficients in evaporation of volatile organic compound from water basin

OpenAIRE

Bunyakan, C.; Malakarn, S.; Tongurai, C.

2002-01-01

Volatile organic compounds (VOCs) have been found in wastewater of many chemical industries. Evaporation of VOCs from open water basin in waste treatment facilities causes air-pollution and has been regulated in many countries. Reduction or prevention of VOCs evaporation from open water basin is then necessary. The aim of this research was to investigate the influence of surface film generated by an insoluble surfactant on the mass transfer coefficient of VOCs evaporating from water. Hexadeca...

Analysis of hydrolyzable tannins and other phenolic compounds in emblic leafflower (Phyllanthus emblica L.) fruits by high performance liquid chromatography-electrospray ionization mass spectrometry.

Science.gov (United States)

Yang, Baoru; Kortesniemi, Maaria; Liu, Pengzhan; Karonen, Maarit; Salminen, Juha-Pekka

2012-09-05

Phenolic compounds were extracted from dried emblic leafflower (Phyllanthus emblica L.) fruits with methanol and separated by Sephadex LH-20 column chromatography. The raw extracts and fractions were analyzed with HPLC coupled with diode array UV spectroscopy, electrospray ionization mass spectrometry, and tandem mass spectrometry. Mucic acid gallate, mucic acid lactone gallate, monogalloylglucose, gallic acid, digalloylglucose, putranjivain A, galloyl-HHDP-glucose, elaeocarpusin, and chebulagic acid were suggested to be the most abundant compounds in the crude methanol extracts of the fruits. In addition, 144 peaks were detected, of which 67 were tentatively identified mostly as ellagitannins, flavonoids, and simple gallic acid derivatives in the fractions. The results indicated the presence of neochebulagic acid, isomers of neochebuloyl galloylglucose, chebuloyl neochebuloyl galloylglucose, ellagic acid glycosides, quercetin glycosides, and eriodictyol coumaroyl glycosides in the fruits. The study provides a systematic report of the retention data and characteristics of UV, MS, and MS/MS spectra of the phenolic compounds in the fruits of emblic leafflower. The fruits of two varieties (Ping Dan No 1 and Fruity) from Guangxi Province differed from those of wild Tian Chuan emblic leafflower from Fujian Province in the content and profile of phenolic compounds.

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.)

Investigations of chemical warfare agents and toxic industrial compounds with proton-transfer-reaction mass spectrometry for a real-time threat monitoring scenario.

Science.gov (United States)

Kassebacher, Thomas; Sulzer, Philipp; Jürschik, Simone; Hartungen, Eugen; Jordan, Alfons; Edtbauer, Achim; Feil, Stefan; Hanel, Gernot; Jaksch, Stefan; Märk, Lukas; Mayhew, Chris A; Märk, Tilmann D

2013-01-30

Security and protection against terrorist attacks are major issues in modern society. One especially challenging task is the monitoring and protection of air conditioning and heating systems of buildings against terrorist attacks with toxic chemicals. As existing technologies have low selectivity, long response times or insufficient sensitivity, there is a need for a novel approach such as we present here. We have analyzed various chemical warfare agents (CWAs) and/or toxic industrial compounds (TICs) and related compounds, namely phosgene, diphosgene, chloroacetone, chloroacetophenone, diisopropylaminoethanol, and triethyl phosphate, utilizing a high-resolution proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOFMS) instrument with the objective of finding key product ions and their intensities, which will allow a low-resolution quadrupole mass spectrometry based PTR-MS system to be used with high confidence in the assignment of threat agents in the atmosphere. We obtained high accuracy PTR-TOFMS mass spectra of the six compounds under study at two different values for the reduced electric field in the drift tube (E/N). From these data we have compiled a table containing product ions, and isotopic and E/N ratios for highly selective threat compound detection with a compact and cost-effective quadrupole-based PTR-MS instrument. Furthermore, using chloroacetophenone (tear gas), we demonstrated that this instrument's response is highly linear in the concentration range of typical Acute Exposure Guideline Levels (AEGLs). On the basis of the presented results it is possible to develop a compact and cost-effective PTR-QMS instrument that monitors air supply systems and triggers an alarm as soon as the presence of a threat agent is detected. We hope that this real-time surveillance device will help to seriously improve safety and security in environments vulnerable to terrorist attacks with toxic chemicals. Copyright © 2012 John Wiley & Sons, Ltd.

Thermal neutron capture gamma-rays

International Nuclear Information System (INIS)

Tuli, J.K.

1983-01-01

The energy and intensity of gamma rays as seen in thermal neutron capture are presented. Only those (n,α), E = thermal, reactions for which the residual nucleus mass number is greater than or equal to 45 are included. These correspond to evaluations published in Nuclear Data Sheets. The publication source data are contained in the Evaluated Nuclear Structure Data File (ENSDF). The data presented here do not involve any additional evaluation. Appendix I lists all the residual nuclides for which the data are included here. Appendix II gives a cumulated index to A-chain evaluations including the year of publication. The capture gamma ray data are given in two tables - the Table 1 is the list of all gamma rays seen in (n,#betta#) reaction given in the order of increasing energy; the Table II lists the gamma rays according to the nuclide

Profiling monoterpenol glycoconjugation in Vitis vinifera L. cv. Muscat of Alexandria using a novel putative compound database approach, high resolution mass spectrometry and collision induced dissociation fragmentation analysis.

Science.gov (United States)

Hjelmeland, Anna K; Zweigenbaum, Jerry; Ebeler, Susan E

2015-08-05

In this work we present a novel approach for the identification of plant metabolites using ultrahigh performance liquid chromatography coupled to accurate mass time-of-flight mass spectrometry. The workflow involves developing an in-house compound database consisting of exact masses of previously identified as well as putative compounds. The database is used to screen accurate mass spectrometry (MS) data to identify possible compound matches. Subsequent tandem MS data is acquired for possible matches and used for structural elucidation. The methodology is applied to profile monoterpene glycosides in Vitis vinifera cv. Muscat of Alexandria grape berries over three developmental stages. Monoterpenes are a subclass of terpenes, the largest class of plant secondary metabolites, and are found in two major forms in the plant, "bound" to one or more sugar moieties or "free" of said sugar moieties. In the free form, monoterpenes are noted for their fragrance and play important roles in plant defense and as attractants for pollinators. However, glycoconjugation renders these compounds odorless, and it is this form that the plant uses for monoterpene storage. In order to gain insight into monoterpene biochemistry and their fate in the plant an analysis of intact glycosides is essential. Eighteen monoterpene glycosides were identified including a monoterpene trisaccharide glycoside, which is tentatively identified here for this first time in any plant. Additionally, while previous studies have identified monoterpene malonylated glucosides in other grapevine tissue, we tentatively identify them for the first time in grape berries. This analytical approach can be readily applied to other plants and the workflow approach can also be used for other classes of compounds. This approach, in general, provides researchers with data to support the identification of putative compounds, which is especially useful when no standard is available. Copyright © 2015 Elsevier B.V. All rights

Boron Neutron Capture Therapy (BCNT) for the Treatment of Liver Metastases: Biodistribution Studies of Boron Compounds in an Experimental Model

Energy Technology Data Exchange (ETDEWEB)

Marcela A. Garabalino; Andrea Monti Hughes; Ana J. Molinari; Elisa M. Heber; Emiliano C. C. Pozzi; Maria E. Itoiz; Veronica A. Trivillin; Amanda E. Schwint; Jorge E. Cardoso; Lucas L. Colombo; Susana Nievas; David W. Nigg; Romina F. Aromando

2011-03-01

Abstract We previously demonstrated the therapeutic efficacy of different boron neutron capture therapy (BNCT) protocols in an experimental model of oral cancer. BNCT is based on the selective accumulation of 10B carriers in a tumor followed by neutron irradiation. Within the context of exploring the potential therapeutic efficacy of BNCT for the treatment of liver metastases, the aim of the present study was to perform boron biodistribution studies in an experimental model of liver metastases in rats. Different boron compounds and administration conditions were assayed to determine which administration protocols would potentially be therapeutically useful in in vivo BNCT studies at the RA-3 nuclear reactor. A total of 70 BDIX rats were inoculated in the liver with syngeneic colon cancer cells DHD/K12/TRb to induce the development of subcapsular tumor nodules. Fourteen days post-inoculation, the animals were used for biodistribution studies. We evaluated a total of 11 administration protocols for the boron compounds boronophenylalanine (BPA) and GB-10 (Na210B10H10), alone or combined at different dose levels and employing different administration routes. Tumor, normal tissue, and blood samples were processed for boron measurement by atomic emission spectroscopy. Six protocols proved potentially useful for BNCT studies in terms of absolute boron concentration in tumor and preferential uptake of boron by tumor tissue. Boron concentration values in tumor and normal tissues in the liver metastases model show it would be feasible to reach therapeutic BNCT doses in tumor without exceeding radiotolerance in normal tissue at the thermal neutron facility at RA-3.

Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method; Etude des fluctuations des largeurs radiatives partielles et totales par la capture des neutrons de resonance

Energy Technology Data Exchange (ETDEWEB)

Huynh, V D [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-06-01

Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)

Soft ionization of saturated hydrocarbons, alcohols and nonpolar compounds by negative-ion direct analysis in real-time mass spectrometry.

Science.gov (United States)

Cody, Robert B; Dane, A John

2013-03-01

Large polarizable n-alkanes (approximately C18 and larger), alcohols, and other nonpolar compounds can be detected as negative ions when sample solutions are injected directly into the sampling orifice of the atmospheric pressure interface of the time-of-flight mass spectrometer with the direct analysis in real time (DART) ion source operating in negative-ion mode. The mass spectra are dominated by peaks corresponding to [M + O2]‾(•). No fragmentation is observed, making this a very soft ionization technique for samples that are otherwise difficult to analyze by DART. Detection limits for cholesterol were determined to be in the low nanogram range.

[Chromatographic mass spectrometric determination of low-molecular-weight aromatic compounds of microbial origin in the serum from patients with sepsis].

Science.gov (United States)

Beloborodova, N V; Arkhipova, A S; Beloborodov, D M; Boĭko, N B; Mel'ko, A I; Olenin, A Iu

2006-02-01

The investigation quantitatively determined the content of low-molecular-weight aromatic compounds of microbial origin in the sera of 34 individuals by chromatographic mass spectrometry. An "Agilent Technogies 6890N" gas chromatograph with a 5973 mass selective detector was applied; chromatographic separation of components was effected on an Hp-5MS quartz capillary column. Aromatic small molecules originating from microbes (SMOM) were determined in the sera of 7 patients with sepsis. The diagnosis of sepsis was documented by the presence of the systemic inflammation syndrome and by that of bacteriemia and/or artificial ventilation-associated pneumonia along with the level of procalcitonin of higher than 10 ng/ml. The levels of aromatic SMOM were compared in 10 healthy donors, 8 preoperative cardiosurgical patients, and 9 patients with different abnormalities without sepsis treated in an intensive care unit (ICU). Serum phenylacetic and 3-phenylpropionic acids were found to be prevalent in the healthy donors and postoperative cardiosurgical patients. In ICU patients with different complications without sepsis, more than half the compounds under study were undetectable, the others were found in very low concentrations, which may be accounted for by antibiotic therapy. At the same time, almost the whole spectrum of the test compounds (other than 3-phenylpropionic acid) with the highest concentrations of 3-phenyllactic, p-hydroxyphenylacetic, 3-(p-hydroxyphenyl)lactic and 2-hydroxybutanic acids, was detectable in septic patients receiving a more intensive therapy. The differences were statistically significant (by the Mann-Whitney U-test; p < 0.05). By taking into account the potentially high biological activity of the test compounds, studies are to be continued in this area.

Neutron Capture Reactions on Fe and Ni Isotopes for the Astrophysical s-process

Energy Technology Data Exchange (ETDEWEB)

Lederer, C., E-mail: claudia.lederer@ed.ac.uk [University of Vienna, Faculty of Physics, 1090 Vienna (Austria); Johann-Wolfgang-Goethe Universität, 60438 Frankfurt (Germany); Giubrone, G. [Instituto de Física Corpuscular, CSIC-Universidad de Valencia, 46071 Valencia (Spain); Massimi, C. [Dipartimento di Fisica, Università di Bologna, and Sezione INFN di Bologna, 40100 Bologna (Italy); Žugec, P. [Department of Physics, Faculty of Science, University of Zagreb, 10002 Zagreb (Croatia); Barbagallo, M.; Colonna, N. [Istituto Nazionale di Fisica Nucleare, 70125 Bari (Italy); Domingo-Pardo, C. [Instituto de Física Corpuscular, CSIC-Universidad de Valencia, 46071 Valencia (Spain); Guerrero, C. [European Organization for Nuclear Research (CERN), CH-1211 Geneva (Switzerland); Gunsing, F. [Commissariat à l' Énergie Atomique (CEA) Saclay – Irfu, 91191 Gif-sur-Yvette (France); Käppeler, F. [Karlsruhe Institute of Technology, Campus Nord, Institut für Kernphysik, 76021 Karlsruhe (Germany); Tain, J.L. [Instituto de Física Corpuscular, CSIC-Universidad de Valencia, 46071 Valencia (Spain); Altstadt, S. [Johann-Wolfgang-Goethe Universität, 60438 Frankfurt (Germany); Andrzejewski, J. [Uniwersytet Łódzki, 90131 Lodz (Poland); Audouin, L. [Centre National de la Recherche Scientifique/IN2P3 – IPN, 91406 Orsay (France); Bécares, V. [Centro de Investigaciones Energeticas Medioambientales y Tecnológicas (CIEMAT), 28040 Madrid (Spain); Bečvář, F. [Faculty of Mathematics and Physics, Charles University, CZ-180 00 Prague (Czech Republic); and others

2014-06-15

Neutron capture cross sections in the keV neutron energy region are the key nuclear physics input to study the astrophysical slow neutron capture process. In the past years, a series of neutron capture cross section measurements has been performed at the neutron time-of-flight facility n{sub T}OF at CERN focussing on the Fe/Ni mass region. Recent results and future developments in the neutron time-of-flight technique are discussed.

Fragmentation pathways and structural characterization of organophosphorus compounds related to the Chemical Weapons Convention by electron ionization and electrospray ionization tandem mass spectrometry.

Science.gov (United States)

Hosseini, Seyed Esmaeil; Saeidian, Hamid; Amozadeh, Ali; Naseri, Mohammad Taghi; Babri, Mehran

2016-12-30

For unambiguous identification of Chemical Weapons Convention (CWC)-related chemicals in environmental samples, the availability of mass spectra, interpretation skills and rapid microsynthesis of suspected chemicals are essential requirements. For the first time, the electron ionization single quadrupole and electrospray ionization tandem mass spectra of a series of O-alkyl N-[bis(dimethylamino)methylidene]-P-methylphosphonamidates (Scheme 1, cpd 4) were studied for CWC verification purposes. O-Alkyl N-[bis(dimethylamino)methylidene]-P-methylphosphonamidates were prepared through a microsynthetic method and were analyzed using electron ionization and electrospray ionization mass spectrometry with gas and liquid chromatography, respectively, as MS-inlet systems. General EI and ESI fragmentation pathways were proposed and discussed, and collision-induced dissociation studies of the protonated derivatives of these compounds were performed to confirm proposed fragment ion structures by analyzing mass spectra of deuterated analogs. Mass spectrometric studies revealed some interesting fragmentation pathways during the ionization process, such as McLafferty rearrangement, hydrogen rearrangement and a previously unknown intramolecular electrophilic aromatic substitution reaction. The EI and ESI fragmentation routes of the synthesized compounds 4 were investigated with the aim of detecting and identifying CWC-related chemicals during on-site inspection and/or off-site analysis and toxic chemical destruction monitoring. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Simultaneous determination of five major compounds in the traditional medicine Pyeongwee-San by high performance liquid chromatography-diode array detection and liquid chromatography-mass spectrometry/mass spectrometry.

Science.gov (United States)

Lee, Bohyoung; Weon, Jin Bae; Yun, Bo-Ra; Lee, Jiwoo; Eom, Min Rye; Ma, Choong Je

2014-01-01

Pyeongwee-San (PWS) has been widely used for treating acute gastritis, chronic, and gastritis. In this paper, simultaneous determination of five compounds (naringin, hesperidin, glycyrrhizin, atractylenolide III, and magnolol) from traditional medicine PWS using the high performance liquid chromatography (HPLC) was established for quality control. Optimum separations were obtained with a SHISEIDO C18 reverse-phase column by gradient elution with 0.1% Trifluoroacetic acid (TFA) water-acetonitrile as the mobile phase. The flow rate was 1 mL/min and detection wavelength was set at 205 nm and 250 nm. Validation of the analytical method was evaluated by linearity, precision, and accuracy test. The calibration curves were linear over the established range with R (2) > 0.9978. The limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.09 to 0.43 and 0.27 to 1.29 μg/mL. The method exhibited intra-day and inter-day precision range between 0.01-1.86% and 0.04-0.35% respectively. The recoveries of five compounds in PWS were in the range between 93.18-106.40%, and 0.20-1.51%. The application of this method was identified through the successful analysis of five compounds in 12 batches of PWS. In addition, identification of five compounds was confirmed by a liquid chromatography method and mass spectrometry. The HPLC method was could be accomplished to the quality control and stable experiment for the preparations consisted of five major compounds.

Review of Livermore-Led Neutron Capture Studies Using DANCE

International Nuclear Information System (INIS)

Parker, W; Sheets, S; Agvaanluvsan, U; Becker, J; Becvar, F; Bredeweg, T; Clement, R; Couture, A; Esch, E; Haight, R; Jandel, M; Krticka, M; Mitchell, G; Macri, R; O'Donnell, J; Reifarth, R; Rundberg, R; Schwantes, J; Ullmann, J; Vieira, D; Wouters, J; Wilk, P

2007-01-01

We have made neutron capture cross-section measurements using the white neutron source at the Los Alamos Science Center, the DANCE detector array (Detector for Advanced Neutron Capture Experiments) and targets important for basic science and stockpile stewardship. In this paper, we review results from (n,γ) reactions on 94,95 Mo, 152,154,157,160,nat Gd, 151,153 Eu and 242m Am for neutron energies from 94,95 Mo, we focused on the spin and parity assignments of the resonances and the determination of the photon strength functions for the compound nuclei 95,96 Mo. Future plans include measurements on actinide targets; our immediate interest is in 242m Am

Perinatal exposure to dioxins and dioxin-like compounds and infant growth and body mass index at seven years

DEFF Research Database (Denmark)

Iszatt, N.; Stigum, H; Govarts, Eva

2016-01-01

Background Dioxins and dioxin-like compounds are endocrine disrupting chemicals (EDCs). Experimental studies suggest perinatal exposure to EDCs results in later obesity. However, the few epidemiological investigations on dioxins are inconclusive. We investigated perinatal exposure to dioxins...... and dioxin-like compounds, infant growth and body mass index (BMI) in childhood. Methods We pooled data from 3 European birth cohorts (Belgian, Norwegian, Slovak) with exposure assessment in cord blood or breast milk. Two cohorts had dioxin-like toxicity assessed using dioxin-responsive chemical......-activated luciferase expression (DR-CALUX) bioassay and one cohort had measured concentrations of dioxins, furans and dioxin-like polychlorinated biphenols with CALUX relative potency values applied. Growth was cohort- and sex-specific change in weight-for-age z-score between birth and 24 months (N = 367). BMI...

Development of Extraction Methods for the Analysis of Perfluorinated Compounds in Leather with High Performance Liquid Chromatography Tandem Mass Spectrometry

Science.gov (United States)

Zhang, Yan; Wang, Youchao; Tang, Chuanjiang; Nie, Jingmei; Xu, Chengtao

2018-01-01

Perfluorinated compounds (PFCs), used to provide water, oil, grease, heat and stain repellency to a range of textile and other products, have been found to be persistent in the environment and are associated with adverse effects on humans and wildlife. This study presents the development and validation of an analytical method to determine the simultaneous presence of eleven PFCs in leather using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The perfluorinated compounds were primarily extracted from the samples by a liquid extraction procedure by ultrasonic, in which the parameters were optimized. Then the solid-phase extraction (SPE) is the most important advantages of the developed methodology. The sample volume and elution conditions were optimized by means of an experimental design. The proposed method was applied to determine the PFCs in leather, where the detection limits of the eleven compounds were 0.09-0.96 ng/L, and the recoveries of all compounds spiked at 5 ng/L concentration level were in the range of 65-96%, with a better RSD lower than 19% (n = 7).

Characterization of the Key Aroma Compounds in Chinese Syrah Wine by Gas Chromatography-Olfactometry-Mass Spectrometry and Aroma Reconstitution Studies.

Science.gov (United States)

Zhao, Pengtao; Gao, Jinxin; Qian, Michael; Li, Hua

2017-06-24

The key aroma compounds and the organoleptic quality of two Chinese Syrah wines from the Yunnan Shangri-La region and Ningxia Helan mountain region were characterized. The most important eighty aroma-active compounds were identified by Gas Chromatography-Olfactometry. In both Syrah samples, ethyl 2-methylpropanoate, ethyl 3-methylbutanoate, 3-methylbutyl acetate, 2- and 3-methyl-1-butanol, ethyl hexanoate, ethyl octanoate, 2-phenethyl acetate, methional, 3-methylbutanoic acid, hexanoic acid, octanoic acid, β -damascenone, guaiacol, 2-phenylethanol, trans -whiskylactone, 4-ethylguaiacol, eugenol, 4-ethylphenol, and sotolon were detected to have the highest odor intensities. In the chemical analysis, 72 compounds were quantitated by Stir Bar Sorptive Extraction combined with Gas Chromatography Mass Spectrometry. Based on the Odor Activity Value (OAV), the aromas were reconstituted by combining aroma compounds in the synthetic wine, and sensory descriptive analysis was used to verify the chemical data. Fatty acid ethyl esters, acetate esters, and β -damascenone were found with higher OAVs in the more fruity-smelling sample of Helan Mountain rather than Shangri-La.

Measurements of neutrino mass

International Nuclear Information System (INIS)

Robertson, R.G.H.

1985-01-01

Direct experimental information of neutrino mass as derived from the study of nuclear and elementary-particle weak decays is reviewed. Topics include tritium beta decay; the 3 He-T mass difference; electron capture decay of 163 Ho and 158 Tb; and limits on massive neutrinos from cosmology. 38 references

Gamma rays from fast neutron capture in silicon and sulphur

International Nuclear Information System (INIS)

Lindholm, A.; Nilsson, L.; Bergqvist, I.

1975-01-01

Gamma-ray spectra from neutron capture in natural samples of silicon and sulphur have been recorded at eight neutron energies between 4 and 15 MeV. Time-of-flight techniques were used to improve the signal-to-background ratio and the gamma radiation was detected by a large NaI(Tl) scintillator. Cross sections have been determined for transitions to individual (or groups of) levels in the final nucleus. Calculations based on the direct-semidirect model show that this model gives a reasonable description of the shapes of the gamma-ray spectra, but fails to account for observed excitation functions. The inclusion of the compound-nucleus capture process gives a conclusive improvement in the description of the excitation functions, in particular at low neutron energies. The ability of the compound-nucleus model to account for the shapes of the gamma-ray spectra is as good as that of the direct-semidirect model. At higher neutron energies, an improvement is obtained for transitions to the region of weakly bound levels, where the single-particle structure is poorly known. (Auth.)

First Penning-trap mass measurement of the electron capture nuclide {sup 163}Ho and its daughter {sup 163}Dy for the ECHO project

Energy Technology Data Exchange (ETDEWEB)

Schneider, Fabian [Institut fuer Kernchemie und Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz (Germany); Collaboration: TRIGA-SPEC Collaboration; ECHo-Collaboration

2015-07-01

The ECHo (Electron Capture of {sup 163}Ho) project aims to determine the mass of the electron neutrino by measuring the calorimetric spectrum of {sup 163}Ho. To be able to extract the neutrino mass from the spectrum near the endpoint a precise knowledge of the decay Q-value is necessary. The ideal way to measure this in a model independent way is by high-precision Penning-trap mass spectrometry. The ECHo collaboration has {sup 163}Ho samples available, which were produced by reactor neutron irradiation. Such samples are typically highly contaminated with radioactive and stable species. These were efficiently removed by chemical purification. Ionization by laser ablation allows high-precision Penning-trap mass measurements with sample sizes of 10{sup 16} atoms. From the measured cyclotron frequency ratio of {sup 163}Ho{sup 16}O{sup +} to {sup 163}Dy{sup 16}O{sup +} we determined the Q-value to be 2.5(7) keV. In addition absolute mass measurements using carbon cluster ions as reference were performed with an uncertainty two times lower than literature values. Future measurements at SHIPTRAP (GSI, Darmstadt) and PENTATRAP (MPIK, Heidelberg) are planned with the aim to drastically improve the uncertainty of the Q-value down to a few eV and thus providing the required input for the ECHo project.

Impacts of carbon capture on power plant emissions

Energy Technology Data Exchange (ETDEWEB)

Narula, R.; Wen, H. [Bechtel Power, San Francisco, CA (United States)

2009-07-01

Post-combustion carbon dioxide capture processes currently include amine-based solvent scrubbing and ammonia solution scrubbing technologies. Both result in high emissions of volatile organic compounds (VOC) and ammonia, as well as liquid discharge that contain chemical solvent. Additional solid wastes include sludge and spent solvent filtration medias. Process simulation software can be used to predict the amount of solvent vapor in the stack gas for both amine and ammonia solvent based capture processes. However, amine could decompose in most amine-based processes and release ammonia gas due to degradation by exposure to oxygen, sulfur impurities, and thermal conditions. As a regulated pollutant for emission control for some plants, ammonia emissions are a major concern for ammonia scrubbing processes. The energy requirement for carbon capture can be reduced by cooling the flue gas before entering the carbon dioxide absorber column. The resulting low flue gas temperature could create difficulties in dispersing the flue gas plume in the atmosphere. This paper presented a computer simulation of stack emission reduction.

Full evaporation dynamic headspace and gas chromatography-mass spectrometry for uniform enrichment of odor compounds in aqueous samples.

Science.gov (United States)

Ochiai, Nobuo; Sasamoto, Kikuo; Hoffmann, Andreas; Okanoya, Kazunori

2012-06-01

A method for analysis of a wide range of odor compounds in aqueous samples at sub-ng mL⁻¹ to μg mL⁻¹ levels was developed by full evaporation dynamic headspace (FEDHS) and gas chromatography-mass spectrometry (GC-MS). Compared to conventional DHS and headspace solid phase microextraction (HS-SPME), FEDHS provides more uniform enrichment over the entire polarity range for odor compounds in aqueous samples. FEDHS at 80°C using 3 L of purge gas allows complete vaporization of 100 μL of an aqueous sample, and trapping and drying it in an adsorbent packed tube, while providing high recoveries (85-103%) of the 18 model odor compounds (water solubility at 25°C: log0.54-5.65 mg L⁻¹, vapor pressure at 25°C: 0.011-3.2 mm Hg) and leaving most of the low volatile matrix behind. The FEDHS-GC-MS method showed good linearity (r²>0.9909) and high sensitivity (limit of detection: 0.21-5.2 ng mL⁻¹) for the model compounds even with the scan mode in the conventional MS. The feasibility and benefit of the method was demonstrated with analyses of key odor compounds including hydrophilic and less volatile characteristics in beverages (whiskey and green tea). In a single malt whiskey sample, phenolic compounds including vanillin could be determined in the range of 0.92-5.1 μg mL⁻¹ (RSDfuraneol, indole, maltol, and pyrazine congeners) were determined in the range of 0.21-110 ng mL⁻¹ (RSD<10%, n=6). Copyright © 2012 Elsevier B.V. All rights reserved.

The mechanism of selective molecular capture in carbon nanotube networks.

Science.gov (United States)

Wan, Yu; Guan, Jun; Yang, Xudong; Zheng, Quanshui; Xu, Zhiping

2014-07-28

Recently, air pollution issues have drawn significant attention to the development of efficient air filters, and one of the most promising materials for this purpose is nanofibers. We explore here the mechanism of selective molecular capture of volatile organic compounds in carbon nanotube networks by performing atomistic simulations. The results are discussed with respect to the two key parameters that define the performance of nanofiltration, i.e. the capture efficiency and flow resistance, which demonstrate the advantages of carbon nanotube networks with high surface-to-volume ratio and atomistically smooth surfaces. We also reveal the important roles of interfacial adhesion and diffusion that govern selective gas transport through the network.

Quantification of character-impacting compounds in Ocimum basilicum and 'Pesto alla Genovese' with selected ion flow tube mass spectrometry.

Science.gov (United States)

Amadei, Gianluca; Ross, Brian M

2012-02-15

Basil (Ocimum basilicum) is an important flavourant plant which constitutes the major ingredient of the pasta sauce 'Pesto alla Genovese'. The characteristic smell of basil stems mainly from a handful of terpenoids (methyl cinnamate, eucalyptol, linalool and estragole), the concentration of which varies according to basil cultivars. The simple and rapid analysis of the terpenoid constituents of basil would be useful as a means to optimise harvesting times and to act as a quality control process for basil-containing foodstuffs. Classical analytical techniques such as gas chromatography/mass spectrometry (GC/MS) are, however, slow, technically demanding and therefore less suitable for routine analysis. A new chemical ionisation technique which allows real-time quantification of traces gases, Selected Ion Flow Tube Mass Spectrometry (SIFT-MS), was therefore utilised to determine its usefulness for the assay of terpenoid concentrations in basil and pesto sauce headspace. Trace gas analysis was performed using the NO(+) precursor ion which minimised interference from other compounds. Character-impacting compound concentration was measured in basil headspace with good reproducibility and statistically significant differences were observed between cultivars. Quantification of linalool in pesto sauce headspace proved more difficult due to the presence of interfering compounds. This was resolved by careful selection of reaction product ions which allowed us to detect differences between various commercial brands of pesto. We conclude that SIFT-MS may be a valid tool for the fast and reproducible analysis of flavourant terpenoids in basil and basil-derived foodstuffs. Copyright © 2011 John Wiley & Sons, Ltd.

Analysis of pharmaceutical and other organic wastewater compounds in filtered and unfiltered water samples by gas chromatography/mass spectrometry

Science.gov (United States)

Zaugg, Steven D.; Phillips, Patrick J.; Smith, Steven G.

2014-01-01

Research on the effects of exposure of stream biota to complex mixtures of pharmaceuticals and other organic compounds associated with wastewater requires the development of additional analytical capabilities for these compounds in water samples. Two gas chromatography/mass spectrometry (GC/MS) analytical methods used at the U.S. Geological Survey National Water Quality Laboratory (NWQL) to analyze organic compounds associated with wastewater were adapted to include additional pharmaceutical and other organic compounds beginning in 2009. This report includes a description of method performance for 42 additional compounds for the filtered-water method (hereafter referred to as the filtered method) and 46 additional compounds for the unfiltered-water method (hereafter referred to as the unfiltered method). The method performance for the filtered method described in this report has been published for seven of these compounds; however, the addition of several other compounds to the filtered method and the addition of the compounds to the unfiltered method resulted in the need to document method performance for both of the modified methods. Most of these added compounds are pharmaceuticals or pharmaceutical degradates, although two nonpharmaceutical compounds are included in each method. The main pharmaceutical compound classes added to the two modified methods include muscle relaxants, opiates, analgesics, and sedatives. These types of compounds were added to the original filtered and unfiltered methods largely in response to the tentative identification of a wide range of pharmaceutical and other organic compounds in samples collected from wastewater-treatment plants. Filtered water samples are extracted by vacuum through disposable solid-phase cartridges that contain modified polystyrene-divinylbenzene resin. Unfiltered samples are extracted by using continuous liquid-liquid extraction with dichloromethane. The compounds of interest for filtered and unfiltered sample

Proceedings of workshop on 'boron chemistry and boron neutron capture therapy'

International Nuclear Information System (INIS)

Kitaoka, Yoshinori

1993-09-01

This volume contains the proceedings of the 5th Workshop on 'the Boron Chemistry and Boron Neutron Capture Therapy' held on February 22 in 1993. The solubility of the boron carrier play an important role in the BNCT. New water-soluble p-boronophenylalanine derivatives are synthesized and their biological activities are investigated (Chap. 2 and 3). Some chemical problems on the BNCT were discussed, and the complex formation reaction of hydroxylboryl compounds were studied by the paper electrophoresis (Chap. 4). The results of the medical investigation on the BNCT using BSH compounds are shown in Chap. 5. Syntheses of o- and m-boronophenylalanine were done and their optical resolution was tried (Chap. 6). The complex formation reaction of p-boronophenylalanine (BPA) with L-DOPA and the oxidation reaction of the analogs are found in Chap. 7. The pka of BPA were determined by the isotachophoresis (Chap. 8). The chemical nature of dihydroxyboryl compounds were investigated by an infrared spectroscopy and electrophoresis (Chap. 9). New synthetic methods of BPA and p-boronophenylserine using ester of isocyanoacetic acid are described in Chap. 10. The induction of chromosomal aberations by neutron capture reaction are discussed from a point of the biological view. The a of the presented papers are indexed individually. (J.P.N.)

Proceedings of the first international symposium on neutron capture therapy

Energy Technology Data Exchange (ETDEWEB)

Fairchild, R.G.; Brownell, G.L. (eds.)

1982-01-01

This meeting was arranged jointly by MIT and BNL in order to illuminate progress in the synthesis and targeting of boron compounds and to evaluate and document progress in radiobiological and dosimetric aspects of neutron capture therapy. It is hoped that this meeting will facilitate transfer of information between groups working in these fields, and encourage synergistic collaboration.

Proceedings of the first international symposium on neutron capture therapy

International Nuclear Information System (INIS)

Fairchild, R.G.; Brownell, G.L.

1982-01-01

This meeting was arranged jointly by MIT and BNL in order to illuminate progress in the synthesis and targeting of boron compounds and to evaluate and document progress in radiobiological and dosimetric aspects of neutron capture therapy. It is hoped that this meeting will facilitate transfer of information between groups working in these fields, and encourage synergistic collaboration

Hybrid Membrane/Absorption Process for Post-combustion CO2 Capture

Energy Technology Data Exchange (ETDEWEB)

Li, Shiguang; Shou, S.; Pyrzynski, Travis; Makkuni, Ajay; Meyer, Howard

2013-12-31

This report summarizes scientific/technical progress made for bench-scale membrane contactor technology for post-combustion CO2 capture from DOE Contract No. DE-FE-0004787. Budget Period 1 (BP1) membrane absorber, Budget Period 2 (BP2) membrane desorber and Budget Period 3 (BP3) integrated system and field testing studies have been completed successfully and met or exceeded the technical targets (≥ 90% CO2 removal and CO2 purity of 97% in one membrane stage). Significant breakthroughs are summarized below: BP1 research: The feasibility of utilizing the poly (ether ether ketone), PEEK, based hollow fiber contractor (HFC) in combination with chemical solvents to separate and capture at least 90% of the CO2 from simulated flue gases has been successfully established. Excellent progress has been made as we have achieved the BP1 goal: ≥ 1,000 membrane intrinsic CO2 permeance, ≥ 90% CO2 removal in one stage, ≤ 2 psi gas side pressure drop, and ≥ 1 (sec)-1 mass transfer coefficient. Initial test results also show that the CO2 capture performance, using activated Methyl Diethanol Amine (aMDEA) solvent, was not affected by flue gas contaminants O2 (~3%), NO2 (66 ppmv), and SO2 (145 ppmv). BP2 research: The feasibility of utilizing the PEEK HFC for CO2-loaded solvent regeneration has been successfully established High CO2 stripping flux, one order of magnitude higher than CO2 absorption flux, have been achieved. Refined economic evaluation based on BP1 membrane absorber and BP2 membrane desorber laboratory test data indicate that the CO2 capture costs are 36% lower than DOE’s benchmark amine absorption technology. BP3 research: A bench-scale system utilizing a membrane absorber and desorber was integrated into a continuous CO2 capture process using contactors containing 10 to 20 ft2 of membrane area. The integrated process operation was stable through a 100-hour laboratory test, utilizing a simulated flue gas stream. Greater than 90% CO2 capture combined with 97

Composite glycerol/graphite/aromatic acid matrices for thin-layer chromatography/matrix-assisted laser desorption/ionization mass spectrometry of heterocyclic compounds.

Science.gov (United States)

Esparza, Cesar; Borisov, R S; Varlamov, A V; Zaikin, V G

2016-10-28

New composite matrices have been suggested for the analysis of mixtures of different synthetic organic compounds (N-containing heterocycles and erectile dysfunction drugs) by thin layer chromatography/matrix-assisted laser desorption ionization time-of-flight mass spectrometry (TLC/MALDI-TOF). Different mixtures of classical MALDI matrices and graphite particles dispersed in glycerol were used for the registration of MALDI mass spectra directly from TLC plates after analytes separation. In most of cases, the mass spectra possessed [M+H] + ions; however, for some analytes only [M+Na] + and [M+K] + ions were observed. These ions have been used to generate visualized TLC chromatograms. The described approach increases the desorption/ionization efficiencies of analytes separated by TLC, prevent spot blurring, simplifies and decrease time for sample preparation. Copyright © 2016 Elsevier B.V. All rights reserved.

Peptidylation for the determination of low-molecular-weight compounds by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Science.gov (United States)

Tang, Feng; Cen, Si-Ying; He, Huan; Liu, Yi; Yuan, Bi-Feng; Feng, Yu-Qi

2016-05-23

Determination of low-molecular-weight compounds by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been a great challenge in the analytical research field. Here we developed a universal peptide-based derivatization (peptidylation) strategy for the sensitive analysis of low-molecular-weight compounds by MALDI-TOF-MS. Upon peptidylation, the molecular weights of target analytes increase, thus avoiding serious matrix ion interference in the low-molecular-weight region in MALDI-TOF-MS. Since peptides typically exhibit good signal response during MALDI-TOF-MS analysis, peptidylation endows high detection sensitivities of low-molecular-weight analytes. As a proof-of-concept, we analyzed low-molecular-weight compounds of aldehydes and thiols by the developed peptidylation strategy. Our results showed that aldehydes and thiols can be readily determined upon peptidylation, thus realizing the sensitive and efficient determination of low-molecular-weight compounds by MALDI-TOF-MS. Moreover, target analytes also can be unambiguously detected in biological samples using the peptidylation strategy. The established peptidylation strategy is a universal strategy and can be extended to the sensitive analysis of various low-molecular-weight compounds by MALDI-TOF-MS, which may be potentially used in areas such as metabolomics.

Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method; Etude des fluctuations des largeurs radiatives partielles et totales par la capture des neutrons de resonance

Energy Technology Data Exchange (ETDEWEB)

Huynh, V.D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-06-01

Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)

Tentative identification of polar and mid-polar compounds in extracts from wine lees by liquid chromatography-tandem mass spectrometry in high-resolution mode.

Science.gov (United States)

Delgado de la Torre, M P; Priego-Capote, F; Luque de Castro, M D

2015-06-01

Sustainable agriculture has a pending goal in the revalorization of agrofood residues. Wine lees are an abundant residue in the oenological industry. This residue, so far, has been used to obtain tartaric acid or pigments but not for being qualitatively characterized as a source of polar and mid-polar compounds such as flavonoids, phenols and essential amino acids. Lees extracts from 11 Spanish wineries have been analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in high resolution mode. The high-resolution power of LC-MS/MS has led to the tentative identification of the most representative compounds present in wine lees, comprising primary amino acids, anthocyans, flavanols, flavonols, flavones and non-flavonoid phenolic compounds, among others. Attending to the profile and content of polar and mid-polar compounds in wine lees, this study underlines the potential of wine lees as an exploitable source to isolate interesting compounds. Copyright © 2015 John Wiley & Sons, Ltd.

An alternative picture of alkali-metal-mediated metallation: cleave and capture chemistry.

Science.gov (United States)

Mulvey, Robert E

2013-05-21

This perspective article takes an alternative look at alkali-metal-mediated chemistry (exchange of a relatively inert C-H bond for a more reactive C-metal bond by a multicomponent reagent usually containing an alkali metal and a less electropositive metal such as magnesium or zinc). It pictures that the cleavage of selected C-H bonds can be accompanied by the capturing of the generated anion by the multi (Lewis acid)-(Lewis base) character of the residue of the bimetallic base. In this way small atoms or molecules (hydrides, oxygen-based anions) as well as sensitive organic anions (of substituted aromatic compounds, ethers or alkenes) can be captured. Cleave and capture reactions which occur in special positions on the organic substrate are also included.

Compound-specific isotope analysis of light elements using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) and its application to geochemistry

International Nuclear Information System (INIS)

Naraoka, Hiroshi; Yamada, Keita; Matsumoto, Kohei; Ishiwatari, Ryoshi

1997-01-01

Compound-specific isotope analysis has been developed recently using gas chromatography/combustion/mass spectrometry (GC/C/IRMS). This paper summarizes principles and progress of GC/C/IRMS, and reviews recent some important works using this new method. GC/C/IRMS is a novel tool for (1) biomarker analysis in sediments and living matter, (2) paleoenvironment analysis including reconstruction of ancient biogeochemical processes, (3) geochemical cycle study of organic compounds in a terrestrial-marine system, (4) evaluation of maturity and diagenesis of organic matter including petroleum formation, (5) ecological analysis, (6) evaluation of anthropologenic pollution in environment, (7) detection of extraterrestrial organic compounds and the formation mechanism study, (8) tracer studies in environment. (author)

Determination of free amino compounds in betalainic fruits and vegetables by gas chromatography with flame ionization and mass spectrometric detection.

Science.gov (United States)

Kugler, Florian; Graneis, Stephan; Schreiter, Pat P-Y; Stintzing, Florian C; Carle, Reinhold

2006-06-14

Amino acids and amines are the precursors of betalains. Therefore, the profiles of free amino compounds in juices obtained from cactus pears [Opuntia ficus-indica (L.) Mill. cv. Bianca, cv. Gialla, and cv. Rossa], pitaya fruits [Selenicereus megalanthus (K. Schumann ex Vaupel) Moran, Hylocereus polyrhizus (Weber) Britton & Rose, and Hylocereus undatus (Haworth) Britton & Rose], and in extracts from differently colored Swiss chard [Beta vulgaris L. ssp. cicla (L.) Alef. cv. Bright Lights] petioles and red and yellow beets (B. vulgaris L. ssp. vulgaris var. conditiva Alef. cv. Burpee's Golden) were investigated for the first time. Amino compounds were derivatized with propyl chloroformate. While gas chromatography (GC) with mass spectrometry was used for peak assignment, GC flame ionization detection was applied for quantification of individual compounds. Whereas proline was the major free amino compound of cactus pear and pitaya fruit juices, glutamine dominated in Swiss chard stems and beets, respectively. Interestingly, extremely high concentrations of dopamine were detected in Swiss chard stems and beets. Furthermore, the cleavage of betaxanthins caused by derivatization in alkaline reaction solutions is demonstrated for the first time. Amino acids and amines thus released might increase the actual free amino compound contents of the respective sample. To evaluate the contribution of betaxanthin cleavage to total amino acid and amine concentration, isolated betaxanthins were derivatized according to the "EZ:faast" method prior to quantification of the respective amino compounds released. On a molar basis, betaxanthin contribution to overall amino compound contents was always below 6.4%.

Research needs for neutron capture therapy

International Nuclear Information System (INIS)

1995-01-01

Key issues and questions addressed by the workshop related to optimization of Boron Neutron Capture Therapy (BNCT), in general, and to the possibility of success of the present BNCT trials at Brookhaven National Laboratory (BNL) and Massachusetts Institute of Technology (MIT), in particular. Both trials use nuclear fission reactors as neutron sources for BNCT of glioblastoma multiforme (BNL) and of deep seated melanoma (MIT). Presentations and discussions focussed on optimal boron-labeled compounds, mainly for brain tumors such as glioblastoma multiforme, and the best mode of compound delivery to the tumor. Also, optimizing neutron irradiation with dose delivery to the tumor cells and the issues of dosimetry of BNCT especially in the brain were discussed. Planning of treatment and of follow-up of patients, coordination of BNCT at various treatment sites, and the potential of delivering BNCT to various types of cancer with an appropriately tailored protocol were additional issues. The need for multicentric interdisciplinary cooperation among the different medical specialties was highlighted

Infrared Laser Ablation with Vacuum Capture for Fingermark Sampling

Science.gov (United States)

Donnarumma, Fabrizio; Camp, Eden E.; Cao, Fan; Murray, Kermit K.

2017-09-01

Infrared laser ablation coupled to vacuum capture was employed to collect material from fingermarks deposited on surfaces of different porosity and roughness. Laser ablation at 3 μm was performed in reflection mode with subsequent capture of the ejecta with a filter connected to vacuum. Ablation and capture of standards from fingermarks was demonstrated on glass, plastic, aluminum, and cardboard surfaces. Using matrix assisted laser desorption ionization (MALDI), it was possible to detect caffeine after spiking with amounts as low as 1 ng. MALDI detection of condom lubricants and detection of antibacterial peptides from an antiseptic cream was demonstrated. Detection of explosives from fingermarks left on plastic surfaces as well as from direct deposition on the same surface using gas chromatography mass spectrometry (GC-MS) was shown. [Figure not available: see fulltext.

Effect of Aging and Surface Interactions on the Diffusion of Endogenous Compounds in Latent Fingerprints Studied by Mass Spectrometry Imaging.

Science.gov (United States)

O'Neill, Kelly C; Lee, Young Jin

2018-05-01

The ability to determine the age of fingerprints would be immeasurably beneficial in criminal investigations. We explore the possibility of determining the age of fingerprints by analyzing various compounds as they diffuse from the ridges to the valleys of fingerprints using matrix-assisted laser desorption/ionization mass spectrometry imaging. The diffusion of two classes of endogenous fingerprint compounds, fatty acids and triacylglycerols (TGs), was studied in fresh and aged fingerprints on four surfaces. We expected higher molecular weight TGs would diffuse slower than fatty acids and allow us to determine the age of older fingerprints. However, we found interactions between endogenous compounds and the surface have a much stronger impact on diffusion than molecular weight. For example, diffusion of TGs is faster on hydrophilic plain glass or partially hydrophilic stainless steel surfaces, than on a hydrophobic Rain-x treated surface. This result further complicates utilizing a diffusion model to age fingerprints. © 2017 American Academy of Forensic Sciences.

Effects of Conventional Heating on the Stability of Major Olive Oil Phenolic Compounds by Tandem Mass Spectrometry and Isotope Dilution Assay

Directory of Open Access Journals (Sweden)

Giovanni Sindona

2010-12-01

Full Text Available The quality of olive oils is sensorially tested by accurate and well established methods. It enables the classification of the pressed oils into the classes of extra virgin oil, virgin oil and lampant oil. Nonetheless, it would be convenient to have analytical methods for screening oils or supporting sensorial analysis using a reliable independent approach based on exploitation of mass spectrometric methodologies. A number of methods have been proposed to evaluate deficiencies of extra virgin olive oils resulting from inappropriate technological treatments, such as high or low temperature deodoration, and home cooking processes. The quality and nutraceutical value of extra virgin olive oil (EVOO can be related to the antioxidant property of its phenolic compounds. Olive oil is a source of at least 30 phenolic compounds, such as oleuropein, oleocanthal, hydroxytyrosol, and tyrosol, all acting as strong antioxidants, radical scavengers and NSAI-like drugs. We now report the efficacy of MRM tandem mass spectrometry, assisted by the isotope dilution assay, in the evaluation of the thermal stability of selected active principles of extra virgin olive oil.

Effects of conventional heating on the stability of major olive oil phenolic compounds by tandem mass spectrometry and isotope dilution assay.

Science.gov (United States)

Attya, Mohamed; Benabdelkamel, Hicham; Perri, Enzo; Russo, Anna; Sindona, Giovanni

2010-12-01

The quality of olive oils is sensorially tested by accurate and well established methods. It enables the classification of the pressed oils into the classes of extra virgin oil, virgin oil and lampant oil. Nonetheless, it would be convenient to have analytical methods for screening oils or supporting sensorial analysis using a reliable independent approach based on exploitation of mass spectrometric methodologies. A number of methods have been proposed to evaluate deficiencies of extra virgin olive oils resulting from inappropriate technological treatments, such as high or low temperature deodoration, and home cooking processes. The quality and nutraceutical value of extra virgin olive oil (EVOO) can be related to the antioxidant property of its phenolic compounds. Olive oil is a source of at least 30 phenolic compounds, such as oleuropein, oleocanthal, hydroxytyrosol, and tyrosol, all acting as strong antioxidants, radical scavengers and NSAI-like drugs. We now report the efficacy of MRM tandem mass spectrometry, assisted by the isotope dilution assay, in the evaluation of the thermal stability of selected active principles of extra virgin olive oil.

[Target and non-target screening of volatile organic compounds in industrial exhaust gas using thermal desorption-gas chromatography-mass spectrometry].

Science.gov (United States)

Ma, Huilian; Jin, Jing; Li, Yun; Chen, Jiping

2017-10-08

A method of comprehensive screening of the target and non-target volatile organic compounds (VOCs) in industrial exhaust gas using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) has been developed. In this paper, two types of solid phase adsorption column were compared, and the Tenex SS TD Tube was selected. The analytes were enriched into the adsorption tube by constant flow sampling, and detected by TD-GC-MS in full scan mode. Target compounds were quantified by internal standard method, and the quantities of non-target compounds were calculated by response coefficient of toluene. The method detection limits (MDLs) for the 24 VOCs were 1.06 to 5.44 ng, and MDLs could also be expressed as 0.004 to 0.018 mg/m 3 assuming that the sampling volume was 300 mL. The average recoveries were in the range of 78.4% to 89.4% with the relative standard deviations (RSDs) of 3.9% to 14.4% ( n =7). The established analytical method was applied for the comprehensive screening of VOCs in a waste incineration power plant in Dalian city. Twenty-nine VOCs were identified. In these compounds, only five VOCs were the target compounds set in advance, which accounted for 26.7% of the total VOCs identified. Therefore, this study further proved the importance of screening non-target compounds in the analysis of VOCs in industrial exhaust gas, and has certain reference significance for the complete determination of VOCs distribution.

EPA Method 8321B (SW-846): Solvent-Extractable Nonvolatile Compounds by High Performance Liquid Chromatography-Thermospray-Mass Spectrometry (HPLC-TS-MS) or Ultraviolet (UV) Detection

Science.gov (United States)

Method 8321B describes procedures for preparation and analysis of solid, aqueous liquid, drinking water and wipe samples using high performance liquid chromatography and mass spectrometry for extractable non-volatile compounds.

Assessing the sensitivity of benzene cluster cation chemical ionization mass spectrometry toward a wide array of biogenic volatile organic compounds

Science.gov (United States)

Lavi, Avi; Vermeuel, Michael; Novak, Gordon; Bertram, Timothy

2017-04-01

Chemical ionization mass spectrometry is a real-time, sensitive and selective measurement technique for the detection of volatile organic compounds (VOCs). The benefits of CIMS technology make it highly suitable for field measurements that requires fast (10Hz and higher) response rates, such as the study of surface-atmosphere exchange processes by the eddy covariance method. The use of benzene cluster cations as a regent ion was previously demonstrated as a sensitive and selective method for the detection of select biogenic VOCs (e.g. isoprene, monoterpenes and sesquiterpenes) [Kim et al., 2016; Leibrock and Huey, 2000]. Quantitative analysis of atmospheric trace gases necessitates calibration for each analyte as a function of atmospheric conditions. We describe a custom designed calibration system, based on liquid evaporation, for determination of the sensitivity of the benzene-CIMS to a wide range of organic compounds at atmospherically relevant mixing ratios (volatile organic compounds, Atmos Meas Tech, 9(4), 1473-1484, doi:10.5194/amt-9-1473-2016. Leibrock, E., and L. G. Huey (2000), Ion chemistry for the detection of isoprene and other volatile organic compounds in ambient air, Geophys Res Lett, 27(12), 1719-1722, doi:Doi 10.1029/1999gl010804.

Solid-Phase Microextraction Coupled to Capillary Atmospheric Pressure Photoionization-Mass Spectrometry for Direct Analysis of Polar and Nonpolar Compounds.

Science.gov (United States)

Mirabelli, Mario F; Zenobi, Renato

2018-04-17

A novel capillary ionization source based on atmospheric pressure photoionization (cAPPI) was developed and used for the direct interfacing between solid-phase microextraction (SPME) and mass spectrometry (MS). The efficiency of the source was evaluated for direct and dopant-assisted photoionization, analyzing both polar (e.g., triazines and organophosphorus pesticides) and nonpolar (polycyclic aromatic hydrocarbons, PAHs) compounds. The results show that the range of compound polarity, which can be addressed by direct SPME-MS can be substantially extended by using cAPPI, compared to other sensitive techniques like direct analysis in real time (DART) and dielectric barrier discharge ionization (DBDI). The new source delivers a very high sensitivity, down to sub parts-per-trillion (ppt), making it a viable alternative when compared to previously reported and less comprehensive direct approaches.

Apparatus for parity-violation study via capture gamma-ray measurements

CERN Document Server

Seestrom, S J; Bowman, J D; Crawford, B C; Haseyama, T; Masaike, A; Matsuda, A; Penttilae, S I; Roberson, R N; Sharapov, E I; Stephenson, S L

1999-01-01

The Time Reversal and Parity at Low Energy (TRIPLE) Collaboration uses a short-pulsed longitudinally polarized epithermal neutron beam at the Los Alamos Neutron Science Center to study spatial parity violation (PV) in the compound nucleus. The typical PV experiment measures the longitudinal cross-section asymmetry by the neutron transmission method through thick samples. Neutron capture gamma-ray measurement provides an alternative method for the study of PV, which enables the use of smaller amounts of isotopically pure target material. In 1995 TRIPLE commissioned a new neutron-capture detector consisting of 24 pure CsI scintillators arranged in a cylindrical geometry around the neutron beam. The characteristics and the performance of the detector and spin transport are described.

Comparison of two common adsorption materials for thermal desorption gas chromatography - mass spectrometry of biogenic volatile organic compounds.

Science.gov (United States)

Marcillo, Andrea; Jakimovska, Viktorija; Widdig, Anja; Birkemeyer, Claudia

2017-09-08

Volatile organic compounds (VOCs) are commonly collected from gaseous samples by adsorption to materials such as the porous polymer Tenax TA. Adsorbed compounds are subsequently released from these materials by thermal desorption (TD) and separated then by gas chromatography (GC) with flame ionization (FID) or mass spectrometry (MS) detection. Tenax TA is known to be particularly suitable for non-polar to semipolar volatiles, however, many volatiles from environmental and biological samples possess a rather polar character. Therefore, we tested if the polymer XAD-2, which so far is widely used to adsorb organic compounds from aqueous and organic solvents, could provide a broader coverage for (semi)polar VOCs during gas-phase sampling. Mixtures of volatile compounds covering a wide range of volatility (bp. 20-256°C) and different chemical classes were introduced by liquid spiking into sorbent tubes with one of the two porous polymers, Tenax TA or XAD-2, and analyzed by TD/GC-MS. At first, an internal standard mixture composed of 17 authentic standards was used to optimize desorption temperature with respect to sorbent degradation and loading time for calibration. Secondly, we tested the detectability of a complex standard mixture composed of 57 volatiles, most of them common constituents of the body odor of mammals. Moreover, the performance of XAD-2 compared with Tenax TA was assessed as limit of quantitation and linearity for the internal standard mixture and 33 compounds from the complex standard mixture. Volatiles were analyzed in a range between 0.01-∼250ng/tube depending on the compound and material. Lower limits of quantitation were between 0.01 and 3 ng±0.9). Interestingly, we found different kinetics for compound adsorption with XAD-2, and a partially better sensitivity in comparison with Tenax TA. For these analytes, XAD-2 might be recommended as an alternative of Tenax TA for TD/GC-MS analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Capture of a quantum particle by a moving trapping potential

International Nuclear Information System (INIS)

Shegelski, Mark R A; Poole, Tyler; Thompson, Cole

2013-01-01

We investigate the capture of a quantum particle in free space by a moving trapping potential. The capture is investigated for various initial conditions. We examine the dependence of the probability of capture on the shape and depth of the trapping potential, initial speed and mass of the particle, and other parameters. We take the trapping potential to move with an initial speed v 0 and to decelerate with constant acceleration a c until the well stops moving. We study the motion during the time the well is moving and after the well has stopped. We compare the probability of capture to the probability that the particle is in a stationary state (while the well is moving) and the probability the particle is in a bound state (after the well's motion has stopped). Our work could be of interest to instructors and students in upper-year undergraduate quantum mechanics courses. (paper)

Resonant electron capture by aspartame and aspartic acid molecules.

Science.gov (United States)

Muftakhov, M V; Shchukin, P V

2016-12-30

The processes for dissociative electron capture are the key mechanisms for decomposition of biomolecules, proteins in particular, under interaction with low-energy electrons. Molecules of aspartic acid and aspartame, i.e. modified dipeptides, were studied herein to define the impact of the side functional groups on peptide chain decomposition in resonant electron-molecular reactions. The processes of formation and decomposition of negative ions of both aspartame and aspartic acid were studied by mass spectrometry of negative ions under resonant electron capture. The obtained mass spectra were interpreted under thermochemical analysis by quantum chemical calculations. Main channels of negative molecular ions fragmentation were found and characteristic fragment ions were identified. The СООН fragment of the side chain in aspartic acid is shown to play a key role like the carboxyl group in amino acids and aliphatic oligopeptides. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

The Importance of Electron Captures in Core-Collapse Supernovae

International Nuclear Information System (INIS)

Langanke, K.; Sampaio, J.M.; Martinez-Pinedo, G.

2004-01-01

Nuclear physics plays an essential role in the dynamics of a type II supernova (a collapsing star). Recent advances in nuclear many-body theory allow now to reliably calculate the stellar weak-interaction processes involving nuclei. The most important process is the electron capture on finite nuclei with mass numbers A > 55. It is found that the respective capture rates, derived from modern many-body models, differ noticeably from previous, more phenomenological estimates. This leads to significant changes in the stellar trajectory during the supernova explosion, as has been found in state-of-the-art supernova simulations. (author)

Mass transfer of nonvolatile organic compounds from porous media

Science.gov (United States)

Khachikian, Crist Simon

This thesis presents data pertaining to the mass transfer of nonvolatile organic compounds from porous media. Physical properties of porous solids, including surface and pore areas, are studied. Information from these studies, along with dissolution data, are used to develop correlations relating the Sherwood Number to the Peclet Number. The contaminant used in this study is naphthalene; the solids used are Moffett Sand (MS), Borden Sand (BS), Lampblack (LB), and Silica Gel (SG). Surface area results indicate that contamination at 0.1% reduces the area of MS and SG by 48 and 37%, respectively, while contamination at 1.0% reduces the area of MS, BS, and SG by 59, 56, and 40%, respectively. Most of the reduction in area originates in the reduction of pore areas and volumes, where the contaminant precipitates. After long-term storage, surface areas did not recover to their original values due to an "irreversible" fraction of naphthalene. Treatment with heat or solvent or both was necessary to completely remove the contamination. For lampblack, treatment at 100°C decreased areas while treatment at 250°C increased them. Treatment at 250°°C probably opened pores while that at 100°C may have blocked more pores by redistributing the tar-like contaminant characteristic of lampblack. Contaminated MS and SG solids are packed in columns through which water is pumped. The effluent began at a relatively high concentration (˜70% of solubility) for both samples. However, SG column concentrations dropped quickly, never achieving steady state while the MS samples declined more gradually towards steady state. The high pore areas of the SG samples are believed to cause this behavior. The steady state portion of the MS dissolution history is used to develop mass transfer correlations. The correlation in this study differs from previous work in two major ways: (1) the exponent on the Pe is three times larger and (2) the limiting Sh is 106 times smaller. These results suggest that

K-electron capture probability in 171Lu

International Nuclear Information System (INIS)

Mishra, N.R.; Vara Prasad, N.V.S.; Chandrasekhara Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L.; Chintalapudi, S.N.

1999-01-01

The K-electron capture probability in the decay of 171 Lu to the 835.06 keV level of the daughter nucleus 171 Yb is measured to be 0.822 ± 0.027 involving two transitions, in agreement with the theoretical value 0.833. The experimental value is seen to be consistent with the mass prediction of the relationship due to Wapstra and Bos. (author)

Neutron capture therapy for melanoma

Energy Technology Data Exchange (ETDEWEB)

Coderre, J.A.; Glass, J.D.; Micca, P.; Fairchild, R.G.

1988-01-01

The development of boron-containing compounds which localize selectively in tumor may require a tumor-by-tumor type of approach that exploits any metabolic pathways unique to the particular type of tumor. Melanin-producing melanomas actively transport and metabolize aromatic amino acids for use as precursors in the synthesis of the pigment melanin. It has been shown that the boron-containing amino acid analog p-borono-phenylalanine (BPA) is selectively accumulated in melanoma tissue, producing boron concentrations in tumor that are within the range estimated to be necessary for successful boron neutron capture therapy (BNCT). We report here the results of therapy experiments carried out at the Brookhaven Medical Research Reactor (BMRR). 21 refs., 5 figs., 3 tabs.

Neutron capture therapy for melanoma

International Nuclear Information System (INIS)

Coderre, J.A.; Glass, J.D.; Micca, P.; Fairchild, R.G.

1988-01-01

The development of boron-containing compounds which localize selectively in tumor may require a tumor-by-tumor type of approach that exploits any metabolic pathways unique to the particular type of tumor. Melanin-producing melanomas actively transport and metabolize aromatic amino acids for use as precursors in the synthesis of the pigment melanin. It has been shown that the boron-containing amino acid analog p-borono-phenylalanine (BPA) is selectively accumulated in melanoma tissue, producing boron concentrations in tumor that are within the range estimated to be necessary for successful boron neutron capture therapy (BNCT). We report here the results of therapy experiments carried out at the Brookhaven Medical Research Reactor (BMRR). 21 refs., 5 figs., 3 tabs

High-accuracy mass determination of unstable nuclei with a Penning trap mass spectrometer

CERN Multimedia

2002-01-01

The mass of a nucleus is its most fundamental property. A systematic study of nuclear masses as a function of neutron and proton number allows the observation of collective and single-particle effects in nuclear structure. Accurate mass data are the most basic test of nuclear models and are essential for their improvement. This is especially important for the astrophysical study of nuclear synthesis. In order to achieve the required high accuracy, the mass of ions captured in a Penning trap is determined via their cyclotron frequency $ \

Neutron-capture Cross Sections from Indirect Measurements

Energy Technology Data Exchange (ETDEWEB)

Escher, J E; Burke, J T; Dietrich, F S; Ressler, J J; Scielzo, N D; Thompson, I J

2011-10-18

Cross sections for compound-nuclear reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

Emission and chemistry of organic compounds from biomass burning: measurements from an iodide time-of-flight chemical ionization mass spectrometer (I- ToF-CIMS) during the FIREX FireLab 2016 intensive

Science.gov (United States)

Yuan, B.; Krechmer, J. E.; Warneke, C.; Coggon, M.; Koss, A.; Lim, C. Y.; Selimovic, V.; Gilman, J.; Lerner, B. M.; Stark, H.; Kang, H.; Jimenez, J. L.; Yokelson, R. J.; Liggio, J.; Roberts, J. M.; Kroll, J. H.; De Gouw, J. A.

2017-12-01

Biomass burning can emit large amounts of many different organic compounds to the atmosphere. The emission strengths of these emitted organic compounds and their subsequent atmospheric chemistry are not well known. In this study, we deployed a time-of-flight chemical ionization mass spectrometer using iodide as reagent ions (Iodide ToF-CIMS) to measure direct emissions of organic compounds during the FIREX laboratory 2016 intensive in the USDA Fire Sciences Lab in Missoula, MT. An interpretation of the I­- TOF-CIMS mass spectra from biomass burning emissions will be presented. The dependence of the emissions of selected organic compounds with fuel types, combustion efficiency and fuel chemical compositions will be discussed. The I- TOF-CIMS also measured aged biomass burning smoke from a small smog chamber and an oxidative flow reactor (OFR). The I- TOF-CIMS consistently observed much higher signals of highly oxygenated organic compounds in the aged biomass burning smoke than in fresh emissions, indicative of strong secondary formation of these organic compounds in biomass burning plumes.

Enhancing Protein Disulfide Bond Cleavage by UV Excitation and Electron Capture Dissociation for Top-Down Mass Spectrometry.

Science.gov (United States)

Wongkongkathep, Piriya; Li, Huilin; Zhang, Xing; Loo, Rachel R Ogorzalek; Julian, Ryan R; Loo, Joseph A

2015-11-15

The application of ion pre-activation with 266 nm ultraviolet (UV) laser irradiation combined with electron capture dissociation (ECD) is demonstrated to enhance top-down mass spectrometry sequence coverage of disulfide bond containing proteins. UV-based activation can homolytically cleave a disulfide bond to yield two separated thiol radicals. Activated ECD experiments of insulin and ribonuclease A containing three and four disulfide bonds, respectively, were performed. UV-activation in combination with ECD allowed the three disulfide bonds of insulin to be cleaved and the overall sequence coverage to be increased. For the larger sized ribonuclease A with four disulfide bonds, irradiation from an infrared laser (10.6 µm) to disrupt non-covalent interactions was combined with UV-activation to facilitate the cleavage of up to three disulfide bonds. Preferences for disulfide bond cleavage are dependent on protein structure and sequence. Disulfide bonds can reform if the generated radicals remain in close proximity. By varying the time delay between the UV-activation and the ECD events, it was determined that disulfide bonds reform within 10-100 msec after their UV-homolytic cleavage.

Mass Proportion, Bioactive Compounds and Antioxidant Capacity of Carrot Peel as Affected by Various Solvents

Directory of Open Access Journals (Sweden)

Van Tang Nguyen

2016-11-01

Full Text Available The aim of this study was to determine the mass proportion of carrot root and the effects of four various solvents (methanol, water, ethanol and hexane on the contents of total phenolics and saponins as well as antioxidant capacity of carrot peel to identify an optimal solvent for effective extraction of bioactive compounds from carrot peel for further investigation. The results showed that carrot root consisted of body, heads and peel with their mass proportion of 83.19%, 5.01% and 14.19% by fresh weight, respectively. Among four solvents tested, methanol obtained the highest levels of extraction yield (54.02% by dry weight, total phenolic content (9.02 mg GAE/g dry weight and antioxidant capacity (DPPH radical scavenging capacity, cupric ion reducing antioxidant capacity, and ferric reducing antioxidant power from carrot peel, while water extracted the highest content of saponins (272.9 mg EE/g dry weight and possessed the maximum ABTS radical scavenging capacity. Therefore, methanol and water are considered for effective extraction of phenolics and saponins from carrot peel, respectively. The phenolic/saponin-enriched extracts are potential sources for further applications in the healthy food and/or pharmaceutical industries.

High-throughput screening and quantitation of guanidino and ureido compounds using liquid chromatography-drift tube ion mobility spectrometry-mass spectrometry

International Nuclear Information System (INIS)

Fan, Ruo-Jing; Zhang, Fang; Chen, Xiu-Ping; Qi, Wan-Shu; Guan, Qing; Sun, Tuan-Qi; Guo, Yin-Long

2017-01-01

The present work focused on the high-throughput screening and quantitation of guanidino compounds (GCs) and ureido compounds (UCs) in human thyroid tissues. The strategy employed benzylic rearrangement stable isotope labeling (BRSIL) for the sample preparation and then detection using liquid chromatography-drift tube ion mobility spectrometry-quadrupole time of flight mass spectrometry (LC-DTIMS-QTOF MS). A short reversed-phase LC realized an on-line desalting and a measurement cycle of 5.0 min. DTIMS separation enhanced the better specificity and selectivity for the benzil labeled GCs and UCs. The elevated mass resolution of QTOF MS enabled measure of the characteristic ions at accurate mass in MS and tandem MS spectra. Collision cross section (CCS) from DTIMS and accurate mass from QTOF MS were used as two qualifiers for the profiling and identification of GCs and UCs. In addition, an integral abundance arising from 3-D ion features (retention time, drift time, m/z) was applied to quantify the GCs and UCs in human thyroid tissues. The quantitative validation indicated good linearity (coefficient values ≥ 0.9981), good precision (1.0%–12.3% for intra-day and 0.9%–7.8% for inter-day) and good accuracy (91%–109%). The results demonstrated that the developed BRSIL coupled with LC-DTIMS-QTOF MS can be a powerful analysis platform to investigate GCs and UCs in human thyroid tissues. - Highlights: • The separation power of DTIMS-MS enhanced peak capacity, spectral clarity, and specificity of benzil labeled GCs and UCs. • Short-column LC for on-line desalting increased the throughput with a measurement cycle of 5.0 min. • CCS and accurate mass as a pair of qualifiers were used for the profiling and identification of GCs and UCs. • An integral abundance arising from 3-D ion features (RT, DT, m/z) was used as a novel quantifier for quantitation. • The developed method was applied to screen and quantify the GCs and UCs in human thyroid tissues.

High-throughput screening and quantitation of guanidino and ureido compounds using liquid chromatography-drift tube ion mobility spectrometry-mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Fan, Ruo-Jing [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 (China); Zhang, Fang, E-mail: fzhang@sioc.ac.cn [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 (China); Chen, Xiu-Ping; Qi, Wan-Shu [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 (China); Guan, Qing [Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Sun, Tuan-Qi, E-mail: tuanqisun@163.com [Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center, Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Guo, Yin-Long, E-mail: ylguo@sioc.ac.cn [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 (China)

2017-04-08

The present work focused on the high-throughput screening and quantitation of guanidino compounds (GCs) and ureido compounds (UCs) in human thyroid tissues. The strategy employed benzylic rearrangement stable isotope labeling (BRSIL) for the sample preparation and then detection using liquid chromatography-drift tube ion mobility spectrometry-quadrupole time of flight mass spectrometry (LC-DTIMS-QTOF MS). A short reversed-phase LC realized an on-line desalting and a measurement cycle of 5.0 min. DTIMS separation enhanced the better specificity and selectivity for the benzil labeled GCs and UCs. The elevated mass resolution of QTOF MS enabled measure of the characteristic ions at accurate mass in MS and tandem MS spectra. Collision cross section (CCS) from DTIMS and accurate mass from QTOF MS were used as two qualifiers for the profiling and identification of GCs and UCs. In addition, an integral abundance arising from 3-D ion features (retention time, drift time, m/z) was applied to quantify the GCs and UCs in human thyroid tissues. The quantitative validation indicated good linearity (coefficient values ≥ 0.9981), good precision (1.0%–12.3% for intra-day and 0.9%–7.8% for inter-day) and good accuracy (91%–109%). The results demonstrated that the developed BRSIL coupled with LC-DTIMS-QTOF MS can be a powerful analysis platform to investigate GCs and UCs in human thyroid tissues. - Highlights: • The separation power of DTIMS-MS enhanced peak capacity, spectral clarity, and specificity of benzil labeled GCs and UCs. • Short-column LC for on-line desalting increased the throughput with a measurement cycle of 5.0 min. • CCS and accurate mass as a pair of qualifiers were used for the profiling and identification of GCs and UCs. • An integral abundance arising from 3-D ion features (RT, DT, m/z) was used as a novel quantifier for quantitation. • The developed method was applied to screen and quantify the GCs and UCs in human thyroid tissues.

Simultaneous determination of phenolic compounds and saponins in quinoa (Chenopodium quinoa Willd) by a liquid chromatography-diode array detection-electrospray ionization-time-of-flight mass spectrometry methodology.

Science.gov (United States)

Gómez-Caravaca, Ana María; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto; Caboni, Maria Fiorenza

2011-10-26

A new liquid chromatography methodology coupled to a diode array detector and a time-of-flight mass spectrometer has been developed for the simultaneous determination of phenolic compounds and saponins in quinoa (Chenopodium quinoa Willd). This method has allowed the simultaneous determination of these two families of compounds with the same analytical method for the first time. A fused-core column C18 has been used, and the analysis has been performed in less than 27 min. Both chromatographic and electrospray ionization time-of-flight mass spectrometry parameters have been optimized to improve the sensitivity and to maximize the number of compounds detected. A validation of the method has also been carried out, and free and bound polar fractions of quinoa have been studied. Twenty-five compounds have been tentatively identified and quantified in the free polar fraction, while five compounds have been tentatively identified and quantified in the bound polar fraction. It is important to highlight that 1-O-galloyl-β-D-glucoside, acacetin, protocatechuic acid 4-O-glucoside, penstebioside, ethyl-m-digallate, (epi)-gallocatechin, and canthoside have been tentatively identified for the first time in quinoa. Free phenolic compounds have been found to be in the range of 2.746-3.803 g/kg of quinoa, while bound phenolic compounds were present in a concentration that varies from 0.139 and 0.164 g/kg. Indeed, saponins have been found to be in a concentration that ranged from 5.6 to 7.5% of the total composition of whole quinoa flour.

Matrix-Assisted Laser Desorption Ionization Mass Spectrometry of Compounds Containing Carboxyl Groups Using CdTe and CuO Nanoparticles

OpenAIRE

Megumi Sakurai; Taro Sato; Jiawei Xu; Soichi Sato; Tatsuya Fujino

2018-01-01

Matrix-assisted laser desorption ionization mass spectrometry of compounds containing carboxyl groups was carried out by using semiconductor nanoparticles (CdTe and CuO) as the matrix. Salicylic acid (Sal), glucuronic acid (Glu), ibuprofen (Ibu), and tyrosine (Tyr) were ionized as deprotonated species (carboxylate anions) by using electrons ejected from CdTe after the photoexcitation. When CuO was used as the matrix, the peak intensity of Tyr became high compared with that obtained with CdTe....

POST-CAPTURE EVOLUTION OF POTENTIALLY HABITABLE EXOMOONS

International Nuclear Information System (INIS)

Porter, Simon B.; Grundy, William M.

2011-01-01

The satellites of extrasolar planets (exomoons) have been recently proposed as astrobiological targets. Since giant planets in the habitable zone are thought to have migrated there, it is possible that they may have captured a former terrestrial planet or planetesimal. We therefore attempt to model the dynamical evolution of a terrestrial planet captured into orbit around a giant planet in the habitable zone of a star. We find that approximately half of loose elliptical orbits result in stable circular orbits over timescales of less than a few million years. We also find that those orbits are mostly at low inclination, but have no prograde/retrograde preference. In addition, we calculate the transit timing and duration variations for the resulting systems, and find that potentially habitable Earth-mass exomoons should be detectable.

Separation and characterization of phenolic compounds from ...

African Journals Online (AJOL)

Attioua

2013-07-03

Jul 3, 2013 ... (Theobroma cacao). J. Mass Spectrom. 38:35-42. Sanchez R, Jauregui LR, Viladomat B, Codina (2004). Qualitative analysis of phenolic compounds in apple Pomace using liquid chromatography coupled to mass spectrometry in tandem mode. Rapid Communun Mass Spectrom. 18:553-563. Saulo LDS ...

Precise mass measurements of exotic nuclei--the SHIPTRAP Penning trap mass spectrometer

International Nuclear Information System (INIS)

Herfurth, F.; Ackermann, D.; Block, M.; Dworschak, M.; Eliseev, S.; Hessberger, F.; Hofmann, S.; Kluge, H.-J.; Maero, G.; Martin, A.; Mazzocco, M.; Rauth, C.; Vorobjev, G.; Blaum, K.; Ferrer, R.; Neidherr, D.; Chaudhuri, A.; Marx, G.; Schweikhard, L.; Neumayr, J.

2007-01-01

The SHIPTRAP Penning trap mass spectrometer has been designed and constructed to measure the mass of short-lived, radioactive nuclei. The radioactive nuclei are produced in fusion-evaporation reactions and separated in flight with the velocity filter SHIP at GSI in Darmstadt. They are captured in a gas cell and transfered to a double Penning trap mass spectrometer. There, the cyclotron frequencies of the radioactive ions are determined and yield mass values with uncertainties ≥4.5·10 -8 . More than 50 nuclei have been investigated so far with the present overall efficiency of about 0.5 to 2%

Applicability of generic assays based on liquid chromatography–electrospray mass spectrometry to study in vitro metabolism of 55 structurally diverse compounds

Directory of Open Access Journals (Sweden)

Timo Rousu

2010-08-01

Full Text Available Liquid chromatography-mass spectrometry (LC/MS with generic gradient elution for a large number of chemically different compounds is a common approach in drug development, used to acquire a large amount of data in a short time frame for drug candidates. The analysis with non-optimised parameters however may lead to a poor method performance for many compounds, and contains a risk of losing important information. Here, generic electrospray-time-of-flight (ESI-TOF MS methods in various pH conditions were tested for 55 chemically diverse compounds (10 acids, 25 bases, 17 neutrals and 3 amphoterics, aiming to find best analytical conditions for each compound, for studies of in vitro metabolic properties in liver preparations. The effect of eluent pH and elution gradient strength on chromatographic performance and electrospray MS ionisation efficiency were examined for each compound. The data are evaluated how well the best generic approach could cover the analysis of test compounds and how many compounds would still need completely different analytical conditions after that. Aqueous mobile phase consisting of 0.05% acetic acid and 5 mM ammonium acetate (pH 4.4 showed the best general suitability for the analyses, showing adequate performance for metabolite profiling for 41 out of 55 compounds either in positive or negative ion mode. In positive ion mode, the main limitation of performance in various pH conditions was generally not the lack of ionisation, but rather the poor chromatographic performance (inadequate retention or poor peak shape, suggesting that more emphasis should be put in finding conditions providing best chromatographic performance, rather than highest ionisation properties. However, a single generic approach for a large number of different compounds is not likely to produce good results for all compounds. Preferably, at least two or three different conditions are needed for the coverage of a larger number of structurally diverse

Warm Dark Matter Sterile Neutrinos in Electron Capture and Beta Decay Spectra

Directory of Open Access Journals (Sweden)

O. Moreno

2016-01-01

Full Text Available We briefly review the motivation to search for sterile neutrinos in the keV mass scale, as dark matter candidates, and the prospects to find them in beta decay or electron capture spectra, with a global perspective. We describe the fundamentals of the neutrino flavor-mass eigenstate mismatch that opens the possibility of detecting sterile neutrinos in such ordinary nuclear processes. Results are shown and discussed for the effect of heavy neutrino emission in electron capture in Holmium 163 and in two isotopes of Lead, 202 and 205, as well as in the beta decay of Tritium. We study the deexcitation spectrum in the considered cases of electron capture and the charged lepton spectrum in the case of Tritium beta decay. For each of these cases, we define ratios of integrated transition rates over different regions of the spectrum under study and give new results that may guide and facilitate the analysis of possible future measurements, paying particular attention to forbidden transitions in Lead isotopes.

Sensitive electrospray mass spectrometry analysis of one-bead-one-compound peptide libraries labeled by quaternary ammonium salts.

Science.gov (United States)

Bąchor, Remigiusz; Cydzik, Marzena; Rudowska, Magdalena; Kluczyk, Alicja; Stefanowicz, Piotr; Szewczuk, Zbigniew

2012-08-01

A rapid and straightforward method for high-throughput analysis of single resin beads from one-bead-one-compound combinatorial libraries with high resolution electrospray ionization tandem mass spectrometry (HR ESI-MS/MS) is presented. The application of an efficient method of peptide derivatization by quaternary ammonium salts (QAS) formation increases ionization efficiency and reduces the detection limit, allowing analysis of trace amounts of compounds by ESI-MS. Peptides, synthesized on solid support, contain a new cleavable linker composed of a Peg spacer (9-aza-3,6,12,15-tetraoxa-10-on-heptadecanoic acid), lysine with ɛ-amino group marked by the N,N,N-triethylglycine salt, and methionine, which makes possible the selective cleavage by cyanogen bromide. Even a small portion of peptides derivatized by QAS cleaved from a single resin bead is sufficient for sequencing by HR ESI-MS/MS experiments. The developed strategy was applied to a small training library of α chymotrypsin substrates. The obtained results confirm the applicability of the proposed method in combinatorial chemistry.

Quantitative analysis of the eight major compounds in the Samsoeum using a high-performance liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometer

Science.gov (United States)

Weon, Jin Bae; Yang, Hye Jin; Lee, Bohyoung; Ma, Jin Yeul; Ma, Choong Je

2015-01-01

Background: Samsoeum was traditionally used for treatment of a respiratory disease. Objective: The simultaneous determination of eight major compounds, ginsenoside Rg3, caffeic acid, puerarin, costunolide, hesperidin, naringin, glycyrrhizin, and 6-gingerol in the Samsoeum using a high-performance liquid chromatography (HPLC) coupled with diode array detection (DAD) and an electrospray ionization mass spectrometer was developed for an accurate and reliable quality assessment. Materials and Methods: Eight compounds were qualitative identified based on their mass spectra and by comparing with standard compounds and quantitative analyzed by HPLC-DAD. Separation of eight compounds was carried out on a LUNA C18 column (S-5 μm, 4.6 mm i.d. ×250 mm) with gradient elution composed of acetonitrile and 0.1% trifluoroacetic acid. Results: The data showed good linearity (R2 > 0.9996). The limits of detection and the limits of quantification were <0.53 μg and 1.62 μg, respectively. Inter- and Intra-day precisions (expressed as relative standard deviation values) were within 1.94% and 1.91%, respectively. The recovery of the method was in the range of 94.24–107.90%. Conclusion: The established method is effective and could be applied to quality control of Samsoeum. PMID:25829771

Method of osmotic energy harvesting using responsive compounds and molecules

KAUST Repository

Hu, Xiao; Cai, Yufeng; Lai, Zhiping; Zhong, Yujiang

2017-01-01

The present invention discloses and claims a more efficient and economical method and system for osmotic energy production and capture using responsive compounds and molecules. The present invention is an energy harvest system enabled by stimuli

Osmotic Compounds Enhance Antibiotic Efficacy against Acinetobacter baumannii Biofilm Communities.

Science.gov (United States)

Falghoush, Azeza; Beyenal, Haluk; Besser, Thomas E; Omsland, Anders; Call, Douglas R

2017-10-01

Biofilm-associated infections are a clinical challenge, in part because a hydrated matrix protects the bacterial community from antibiotics. Herein, we evaluated how different osmotic compounds (maltodextrin, sucrose, and polyethylene glycol [PEG]) enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities. Established (24-h) test tube biofilms (strain ATCC 17978) were treated with osmotic compounds in the presence or absence of 10× the MIC of different antibiotics (50 μg/ml tobramycin, 20 μg/ml ciprofloxacin, 300 μg/ml chloramphenicol, 30 μg/ml nalidixic acid, or 100 μg/ml erythromycin). Combining antibiotics with hypertonic concentrations of the osmotic compounds for 24 h reduced the number of biofilm bacteria by 5 to 7 log ( P baumannii strains were similarly treated with 400-Da PEG and tobramycin, resulting in a mean 2.7-log reduction in recoverable bacteria compared with tobramycin treatment alone. Multivariate regression models with data from different osmotic compounds and nine antibiotics demonstrated that the benefit from combining hypertonic treatments with antibiotics is a function of antibiotic mass and lipophilicity ( r 2 > 0.82; P baumannii and Escherichia coli K-12. Augmenting topical antibiotic therapies with a low-mass hypertonic treatment may enhance the efficacy of antibiotics against wound biofilms, particularly when using low-mass hydrophilic antibiotics. IMPORTANCE Biofilms form a barrier that protects bacteria from environmental insults, including exposure to antibiotics. We demonstrated that multiple osmotic compounds can enhance antibiotic efficacy against Acinetobacter baumannii biofilm communities, but viscosity is a limiting factor, and the most effective compounds have lower molecular mass. The synergism between osmotic compounds and antibiotics is also dependent on the hydrophobicity and mass of the antibiotics. The statistical models presented herein provide a basis for predicting the optimal combination of

Chemosensors for detection of nitroaromatic compounds (explosives)

Science.gov (United States)

Zyryanov, G. V.; Kopchuk, D. S.; Kovalev, I. S.; Nosova, E. V.; Rusinov, V. L.; Chupakhin, O. N.

2014-09-01

The key types of low-molecular-mass chemosensors for the detection of nitroaromatic compounds representing energetic substances (explosives) are analyzed. The coordination and chemical properties of these chemosensors and structural features of their complexes with nitroaromatic compounds are considered. The causes and methods for attaining high selectivity of recognition are demonstrated. The primary attention is paid to the use of low-molecular-mass chemosensors for visual detection of explosives of this class by colorimetric and photometric methods. Examples of using photo- and chemiluminescence for this purpose are described. A separate section is devoted to electrochemical methods of detection of nitroaromatic compounds. Data published from 2000 to 2014 are mainly covered. The bibliography includes 245 references.

Chemosensors for detection of nitroaromatic compounds (explosives)

International Nuclear Information System (INIS)

Zyryanov, G V; Kopchuk, D S; Rusinov, V L; Chupakhin, O N; Kovalev, I S; Nosova, E V

2014-01-01

The key types of low-molecular-mass chemosensors for the detection of nitroaromatic compounds representing energetic substances (explosives) are analyzed. The coordination and chemical properties of these chemosensors and structural features of their complexes with nitroaromatic compounds are considered. The causes and methods for attaining high selectivity of recognition are demonstrated. The primary attention is paid to the use of low-molecular-mass chemosensors for visual detection of explosives of this class by colorimetric and photometric methods. Examples of using photo- and chemiluminescence for this purpose are described. A separate section is devoted to electrochemical methods of detection of nitroaromatic compounds. Data published from 2000 to 2014 are mainly covered. The bibliography includes 245 references

Gas chromatography--inductively coupled plasma--time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental water samples.

Science.gov (United States)

Heisterkamp, M; Adams, F C

2001-07-01

The application of inductively coupled plasma--time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental waters is described. Construction of the transfer line was achieved by means of a relatively simple and rapid coupling procedure. Derivatization of the ionic lead species was achieved by in-situ propylation with sodium tetrapropylborate; simultaneous extraction of the derivatized compounds in hexane was followed by separation and detection by capillary gas chromatography hyphenated to inductively coupled plasma-time-of-flight mass spectrometry. Detection limits for the different organolead species ranged from 10 to 15 fg (as Pb), corresponding to procedural detection limits between 50 and 75 ng L(-1), on the basis of a 50 mL snow sample, extraction with 200 microL hexane, and subsequent injection of 1 microL of the organic extract on to the column. The accuracy of the system was confirmed by additional analysis of the water samples by capillary gas chromatography coupled with microwave-induced plasma-atomic-emission spectrometry and the analysis of a standard reference material CRM 605 (road dust) with a certified content of trimethyllead.

Asteroid Redirect Robotic Mission: Robotic Boulder Capture Option Overview

Science.gov (United States)

Mazanek, Daniel D.; Merrill, Raymond G.; Belbin, Scott P.; Reeves, David M.; Earle, Kevin D.; Naasz, Bo J.; Abell, Paul A.

2014-01-01

The National Aeronautics and Space Administration (NASA) is currently studying an option for the Asteroid Redirect Robotic Mission (ARRM) that would capture a multi-ton boulder (typically 2-4 meters in size) from the surface of a large (is approximately 100+ meter) Near-Earth Asteroid (NEA) and return it to cislunar space for subsequent human and robotic exploration. This alternative mission approach, designated the Robotic Boulder Capture Option (Option B), has been investigated to determine the mission feasibility and identify potential differences from the initial ARRM concept of capturing an entire small NEA (4-10 meters in size), which has been designated the Small Asteroid Capture Option (Option A). Compared to the initial ARRM concept, Option B allows for centimeter-level characterization over an entire large NEA, the certainty of target NEA composition type, the ability to select the boulder that is captured, numerous opportunities for mission enhancements to support science objectives, additional experience operating at a low-gravity planetary body including extended surface contact, and the ability to demonstrate future planetary defense strategies on a hazardous-size NEA. Option B can leverage precursor missions and existing Agency capabilities to help ensure mission success by targeting wellcharacterized asteroids and can accommodate uncertain programmatic schedules by tailoring the return mass.

Capture orbits around asteroids by hitting zero-velocity curves

Science.gov (United States)

Wang, Wei; Yang, Hongwei; Zhang, Wei; Ma, Guangfu

2017-12-01

The problem of capturing a spacecraft from a heliocentric orbit into a high parking orbit around binary asteroids is investigated in the current study. To reduce the braking Δ V, a new capture strategy takes advantage of the three-body gravity of the binary asteroid to lower the inertial energy before applying the Δ V. The framework of the circular restricted three-body problem (CR3BP) is employed for the binary asteroid system. The proposed capture strategy is based on the mechanism by which inertial energy can be decreased sharply near zero-velocity curves (ZVCs). The strategy has two steps, namely, hitting the target ZVC and raising the periapsis by a small Δ V at the apoapsis. By hitting the target ZVC, the positive inertial energy decreases and becomes negative. Using a small Δ V, the spacecraft inserts into a bounded orbit around the asteroid. In addition, a rotating mass dipole model is employed for elongated asteroids, which leads to dynamics similar to that of the CR3BP. With this approach, the proposed capture strategy can be applied to elongated asteroids. Numerical simulations validate that the proposed capture strategy is applicable for the binary asteroid 90 Antiope and the elongated asteroid 216 Kleopatra.

Boron neutron capture therapy of malignant brain tumors at the Brookhaven Medical Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Joel, D.D.; Coderre, J.A.; Chanana, A.D. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.

1996-12-31

Boron neutron capture therapy (BNCT) is a bimodal form of radiation therapy for cancer. The first component of this treatment is the preferential localization of the stable isotope {sup 10}B in tumor cells by targeting with boronated compounds. The tumor and surrounding tissue is then irradiated with a neutron beam resulting in thermal neutron/{sup 10}B reactions ({sup 10}B(n,{alpha}){sup 7}Li) resulting in the production of localized high LET radiation from alpha and {sup 7}Li particles. These products of the neutron capture reaction are very damaging to cells, but of short range so that the majority of the ionizing energy released is microscopically confined to the vicinity of the boron-containing compound. In principal it should be possible with BNCT to selectively destroy small nests or even single cancer cells located within normal tissue. It follows that the major improvements in this form of radiation therapy are going to come largely from the development of boron compounds with greater tumor selectivity, although there will certainly be advances made in neutron beam quality as well as the possible development of alternative sources of neutron beams, particularly accelerator-based epithermal neutron beams.

Boron neutron capture therapy of malignant brain tumors at the Brookhaven Medical Research Reactor

International Nuclear Information System (INIS)

Joel, D.D.; Coderre, J.A.; Chanana, A.D.

1996-01-01

Boron neutron capture therapy (BNCT) is a bimodal form of radiation therapy for cancer. The first component of this treatment is the preferential localization of the stable isotope 10 B in tumor cells by targeting with boronated compounds. The tumor and surrounding tissue is then irradiated with a neutron beam resulting in thermal neutron/ 10 B reactions ( 10 B(n,α) 7 Li) resulting in the production of localized high LET radiation from alpha and 7 Li particles. These products of the neutron capture reaction are very damaging to cells, but of short range so that the majority of the ionizing energy released is microscopically confined to the vicinity of the boron-containing compound. In principal it should be possible with BNCT to selectively destroy small nests or even single cancer cells located within normal tissue. It follows that the major improvements in this form of radiation therapy are going to come largely from the development of boron compounds with greater tumor selectivity, although there will certainly be advances made in neutron beam quality as well as the possible development of alternative sources of neutron beams, particularly accelerator-based epithermal neutron beams

Dissociative electron attachment negative ion mass spectrometry: a chlorine-specific detector for gas chromatography

Science.gov (United States)

Curtis, Jonathan M.; Boyd, Robert K.

1997-11-01

This work describes the application of negative ion chemical ionization, optimized for dissociative electron attachment (DEA), to location of unknown trace chlorinated compounds in complex gas chromatograms by selected ion recording (SIR) of m / z 35 and 37. The DEA-SIR technique is compared with other GC detectors, including the electron capture detector, electrolytic conductivity detector, the atomic emission detector and the chemical reaction interface mass spectrometry method, with respect to selectivity for chlorine, sensitivity, linear dynamic range, and general robustness and ease of use. When applied to quantitative analysis of target analytes such as polychlorobiphenyls, the DEA-SIR method has potential problems arising from the possibility of suppression effects due to abundant co-eluting components, and possible alleviating measures are discussed. In addition to these practical investigations, literature information on the fundamental physical and chemical phenomena underlying the DEA process is summarized in order to guide future work on extension to other compound types and on general improvements to the technique.

The radiative capture of fast nucleons in the mass area of medium and heavy nuclei

International Nuclear Information System (INIS)

Rigaud, F.

1978-01-01

The radiative capture of 14 MeV neutrons cross-sections on the 59 Co, 93 Nb, 103 Rh, 133 Cs, 139 La, Ce and 159 Tb nuclei were investigated by the integration method and by the activation method on the 27 Al, 50 Ti, 51 V, 103 Rh, 127 I and 139 La nuclei. The gamma-ray spectra following the capture of 8-22 MeV protons on 110 Cd and 115 In nuclei were measured and the single-particle states capture cross-sections deduced. The 110 Cd(p,γ 0 ) 111 In angular distribution was also measured at 13 MeV. The direct and semi-direct processes explained the experimental results. The volume form of the coupling interaction was adequate to account the neutrons results and the surface form to account the 110 Cd(p,γ 0 ) 111 In results. The 110 Cd nuclei electric quadrupole excitation was formed negligible compared with the electric dipole excitation which is adequate to explain the 110 Cd(p,γ 0 ) 111 In excitation function [fr

In cleanroom, sub-ppb real-time monitoring of volatile organic compounds using proton-transfer reaction/time of flight/mass spectrometry

Science.gov (United States)

Hayeck, Nathalie; Maillot, Philippe; Vitrani, Thomas; Pic, Nicolas; Wortham, Henri; Gligorovski, Sasho; Temime-Roussel, Brice; Mizzi, Aurélie; Poulet, Irène

2014-04-01

Refractory compounds such as Trimethylsilanol (TMS) and other organic compounds such as propylene glycol methyl ether acetate (PGMEA) used in the photolithography area of microelectronic cleanrooms have irreversible dramatic impact on optical lenses used on photolithography tools. There is a need for real-time, continuous measurements of organic contaminants in representative cleanroom environment especially in lithography zone. Such information is essential to properly evaluate the impact of organic contamination on optical lenses. In this study, a Proton-Transfer Reaction-Time-of-Flight Mass spectrometer (PTR-TOF-MS) was applied for real-time and continuous monitoring of fugitive organic contamination induced by the fabrication process. Three types of measurements were carried out using the PTR-TOF-MS in order to detect the volatile organic compounds (VOCs) next to the tools in the photolithography area and at the upstream and downstream of chemical filters used to purge the air in the cleanroom environment. A validation and verification of the results obtained with PTR-TOF-MS was performed by comparing these results with those obtained with an off-line technique that is Automated Thermal Desorber - Gas Chromatography - Mass Spectrometry (ATD-GC-MS) used as a reference analytical method. The emerged results from the PTR-TOF-MS analysis exhibited the temporal variation of the VOCs levels in the cleanroom environment during the fabrication process. While comparing the results emerging from the two techniques, a good agreement was found between the results obtained with PTR-TOF-MS and those obtained with ATD-GC-MS for the PGMEA, toluene and xylene. Regarding TMS, a significant difference was observed ascribed to the technical performance of both instruments.

Photoneutron cross sections measurements in 9Be, 13C e 17O with thermal neutron capture gamma-rays

International Nuclear Information System (INIS)

Semmler, Renato

2006-01-01

Photoneutron cross sections measurements of 9 Be, 13 C and 17 O have been obtained in the energy interval between 1,6 and 10,8 MeV, using neutron capture gamma-rays with high resolution in energy (3 a 21 eV), produced by 21 target materials, placed inside a tangential beam port, near the core of the IPEN/CNEN-SP IEA-R1 (5 MW) research reactor. The samples have been irradiated inside a 4π geometry neutron detector system 'Long Counter', 520,5 cm away from the capture target. The capture gamma-ray flux was determined by means of the analysis of the gamma spectrum obtained by using a Ge(Li) solid-state detector (EG and G ORTEC, 25 cm 3 , 5%), previously calibrated with capture gamma-rays from a standard target of Nitrogen (Melamine). The neutron photoproduction cross section has been measured for each target capture gamma-ray spectrum (compound cross section). A inversion matrix methodology to solve inversion problems for unfolding the set of experimental compound cross sections, was used in order to obtain the cross sections at specific excitation energy values (principal gamma line energies of the capture targets). The cross sections obtained at the energy values of the principal gamma lines were compared with experimental data reported by other authors, with have employed different gamma-ray sources. A good agreement was observed among the experimental data in this work with reported in the literature. (author)

Devices for collecting chemical compounds

Science.gov (United States)

Scott, Jill R; Groenewold, Gary S

2013-12-24

A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

Molecular-level characterization of crude oil compounds combining reversed-phase high-performance liquid chromatography with off-line high-resolution mass spectrometry

Science.gov (United States)

Sim, Arum; Cho, Yunju; Kim, Daae; Witt, Matthias; Birdwell, Justin E.; Kim, Byung Ju; Kim, Sunghwan

2014-01-01

A reversed-phase separation technique was developed in a previous study (Loegel et al., 2012) and successfully applied to the de-asphalted fraction of crude oil. However, to the best of our knowledge, the molecular-level characterization of oil fractions obtained by reversed-phase high-performance liquid chromatography (HPLC) coupled with high-resolution mass spectrometry (MS) has not yet been reported. A detailed characterization of the oil fractions prepared by reversed-phase HPLC was performed in this study. HPLC fractionation was carried out on conventional crude oil and an oil shale pyrolysate. The analyses of the fractions showed that the carbon number of alkyl chains and the double bond equivalent (DBE) value were the major factors determining elution order. The compounds with larger DBE (presumably more condensed aromatic structures) and smaller carbon number (presumably compounds with short side chains) were eluted earlier but those compounds with lower DBE values (presumably less aromatic structures) and higher carbon number (presumably compounds with longer alkyl chains) eluted later in the chromatograms. This separation behavior is in good agreement with that expected from the principles of reversed-phase separation. The data presented in this study show that reversed-phase chromatography is effective in separating crude oil compounds and can be combined with ultrahigh-resolution MS data to better understand natural oils and oil shale pyrolysates.

Neutron-capture cross sections from indirect measurements

Directory of Open Access Journals (Sweden)

Scielzo N.D.

2012-02-01

Full Text Available Cross sections for compound-nuclear reactions reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f reactions, but need to be improved upon for applications to capture reactions.

Measurements of Volatile Organic Compounds Using Proton Transfer Reaction – Mass Spectrometry during the MILAGRO 2006 Campaign

Directory of Open Access Journals (Sweden)

E. C. Fortner

2009-01-01

Full Text Available Volatile organic compounds (VOCs were measured by proton transfer reaction – mass spectrometry (PTR-MS on a rooftop in the urban mixed residential and industrial area North Northeast of downtown Mexico City as part of the Megacity Initiative – Local and Global Research Observations (MILAGRO 2006 field campaign. Thirty eight individual masses were monitored during the campaign and many species were quantified including methanol, acetaldehyde, toluene, the sum of C₂ benzenes, the sum of C₃ benzenes, acetone, isoprene, benzene, and ethyl acetate. The VOC measurements were analyzed to gain a better understanding of the type of VOCs present in the MCMA, their diurnal patterns, and their origins. Diurnal profiles of weekday and weekend/holiday aromatic VOC concentrations showed the influence of vehicular traffic during the morning rush hours and during the afternoon hours. Plumes including elevated toluene as high as 216 parts per billion (ppb and ethyl acetate as high as 183 ppb were frequently observed during the late night and early morning hours, indicating the possibility of significant industrial sources of the two compounds in the region. Wind fields during those peak episodes revealed no specific direction for the majority of the toluene plumes but the ethyl acetate plumes arrived at the site when winds were from the Southwest or West. The PTR-MS measurements combined with other VOC measuring techniques at the field site as well as VOC measurements conducted in other areas of the Mexico City Metropolitan Area (MCMA will help to develop a better understanding of the spatial pattern of VOCs and its variability in the MCMA.

Specific RNP capture with antisense LNA/DNA mixmers.

Science.gov (United States)

Rogell, Birgit; Fischer, Bernd; Rettel, Mandy; Krijgsveld, Jeroen; Castello, Alfredo; Hentze, Matthias W

2017-08-01

RNA-binding proteins (RBPs) play essential roles in RNA biology, responding to cellular and environmental stimuli to regulate gene expression. Important advances have helped to determine the (near) complete repertoires of cellular RBPs. However, identification of RBPs associated with specific transcripts remains a challenge. Here, we describe "specific ribonucleoprotein (RNP) capture," a versatile method for the determination of the proteins bound to specific transcripts in vitro and in cellular systems. Specific RNP capture uses UV irradiation to covalently stabilize protein-RNA interactions taking place at "zero distance." Proteins bound to the target RNA are captured by hybridization with antisense locked nucleic acid (LNA)/DNA oligonucleotides covalently coupled to a magnetic resin. After stringent washing, interacting proteins are identified by quantitative mass spectrometry. Applied to in vitro extracts, specific RNP capture identifies the RBPs bound to a reporter mRNA containing the Sex-lethal (Sxl) binding motifs, revealing that the Sxl homolog sister of Sex lethal (Ssx) displays similar binding preferences. This method also revealed the repertoire of RBPs binding to 18S or 28S rRNAs in HeLa cells, including previously unknown rRNA-binding proteins. © 2017 Rogell et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

Chapter 3. Determination of semivolatile organic compounds and polycyclic aromatic hydrocarbons in solids by gas chromatography/mass spectrometry

Science.gov (United States)

Zaugg, Steven D.; Burkhardt, Mark R.; Burbank, Teresa L.; Olson, Mary C.; Iverson, Jana L.; Schroeder, Michael P.

2006-01-01

A method for the determination of 38 polycyclic aromatic hydrocarbons (PAHs) and semivolatile organic compounds in solid samples is described. Samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from the solid sample twice at 13,800 kilopascals; first at 120 degrees Celsius using a water/isopropyl alcohol mixture (50:50, volume-to-volume ratio), and then the sample is extracted at 200 degrees Celsius using a water/isopropyl alcohol mixture (80:20, volume-to-volume ratio). The compounds are isolated using disposable solid-phase extraction (SPE) cartridges containing divinylbenzene-vinylpyrrolidone copolymer resin. The cartridges are dried with nitrogen gas, and then sorbed compounds are eluted from the SPE material using a dichloromethane/diethyl ether mixture (80:20, volume-to-volume ratio) and passed through a sodium sulfate/Florisil SPE cartridge to remove residual water and to further clean up the extract. The concentrated extract is solvent exchanged into ethyl acetate and the solvent volume reduced to 0.5 milliliter. Internal standard compounds are added prior to analysis by capillary-column gas chromatography/mass spectrometry. Comparisons of PAH data for 28 sediment samples extracted by Soxhlet and the accelerated solvent extraction (ASE) method described in this report produced similar results. Extraction of PAH compounds from standard reference material using this method also compared favorably with Soxhlet extraction. The recoveries of PAHs less than molecular weight 202 (pyrene or fluoranthene) are higher by up to 20 percent using this ASE method, whereas the recoveries of PAHs greater than or equal to molecular weight 202 are equivalent. This ASE method of sample extraction of solids has advantages over conventional Soxhlet extraction by increasing automation of the extraction process, reducing extraction time, and using less solvent. Extract cleanup also is greatly simplified because SPE replaces

Vapour pressures of selected organic compounds down to 1 mPa, using mass-loss Knudsen effusion method

International Nuclear Information System (INIS)

Fonseca, José M.S.; Gushterov, Nikola; Dohrn, Ralf

2014-01-01

Graphical abstract: - Highlights: • A recently described mass-loss Knudsen apparatus was used for measurements of vapour pressures down to around 1 mPa. • Complementary calorimetric studies were performed in a Calvet-type calorimeter. • New vapour pressures are given for benzoic acid and benzanthrone, in ranges in which no consistent data existed. • Vapour pressures for solid n-octadecane are presented, correcting existing values from literature. - Abstract: A recently developed Knudsen effusion apparatus was improved and used for measurements of vapour pressures of selected organic compounds. Calorimetric studies were conducted using a Calvet-type calorimeter, complementing the information obtained for the vapour pressures and facilitating the modelling and analysis of the data. Vapour pressures of benzoic acid, a reference substance, were determined at temperatures between 269 K and 317 K, corresponding to a pressure range from 2 mPa to 1 Pa, extending the range of results available in the literature to lower pressures. Benzanthrone was studied between temperatures 360 K and 410 K (5 mPa–1 Pa) in order to test the apparatus at higher temperatures. Values presented in the literature for the vapour pressure of solid n-octadecane, one of the most promising compounds to be used as “phase change material” for textile applications, were found inconsistent with the triple point of the substance. Sublimation pressures were measured for this compound between T = 286 K and 298 K (2–20 mPa) allowing the correction of the existing values. Finally, vapour pressures of diphenyl carbonate, a compound of high industrial relevance for its use in the production of polycarbonates, were determined from T = 302 K to 332 K (0.02–1 Pa)

Masses of noble gases

CERN Document Server

Marx, G H; Herfurth, F; Stora, T; Blaum, K; Beck, D; Audi, G; Rosenbusch, M

The so-called magic numbers, cornerstones of the quantum nuclear ensemble, are now known to lose their supernatural powers far from the protected valley of stability. To complement the well-established (but not yet well-understood) case of N = 20, we propose to examine the erstwhile N = 28 shell closure via a measurement of the important (but unknown) mass of the nuclide $^{48}$Ar. The quenching of a shell closure, a mechanism as mysterious as the reason for magic numbers themselves, also has important consequences in nucleosynthesis. While $^{48}$Ar is not part of the region concerned by the canonical rapid neutro-capture r-process, the question of shell strength is of great importance for heavier nuclides. The location of the r-process path would benefit from extending the succesful ISOTRAP krypton mass measurements beyond the N = 58 sub-shell to $^{96-98}$Kr. Modeling the complementary rapid proton-capture rp- process, putative source of some proton-rich species, requires the mass of $^{70}$Kr, near the e...

Process and Material Design for Micro-Encapsulated Ionic Liquids in Post-Combustion CO₂ Capture

Energy Technology Data Exchange (ETDEWEB)

Hong, Bo [Univ. of Notre Dame, IN (United States); Brennecke, Joan F [Univ. of Notre Dame, IN (United States); McCready, Mark [Univ. of Notre Dame, IN (United States); Stadtherr, Mark [Univ. of Notre Dame, IN (United States)

2016-11-18

Aprotic Heterocyclic Anion (AHA) Ionic Liquids (ILs) have been identified as promising new solvents for post-combustion carbon capture due to their high CO₂ uptake and the high tenability 1,2 of their binding energy with CO₂. Some of these compounds change phase (solid to liquid) on absorption of CO₂; these Phase Change ILs (PCILs)3 offer the additional advantage that part of the heat needed to desorb the CO2 from the absorbent is provided by the heat of fusion as the PCIL solidifies upon release of CO₂. However, the relatively high viscosity of AHA ILs and the occurrence of a phase change in PCILs present challenges for conventional absorption equipment. To overcome these challenges we are pursuing the use of new technology to micro-encapsulate the AHA ILs and PCILs. Our partners at Lawrence Livermore National Laboratory have successfully demonstrated this technology in the application of post-combustion carbon capture with sodium and potassium carbonate solutions,4 and have recently shown the feasibility of micro-encapsulation of an AHA IL for carbon capture.5 The large effective surface area and high CO₂ permeability of the micro-capsules is expected to offset the drawback of the high IL viscosity and to provide for a more efficient and cost-effective mass transfer operation involving AHA ILs and PCILs. These opportunities, however, present us with both process and materials design questions. For example, what is the target CO₂ absorption strength (enthalpy of chemical absorption) for the tunable AHA IL? What is the target for micro-capsule diameter in order to obtain a high mass transfer rate and good fluidization performance? What are the appropriate temperatures and pressures for the absorber and stripper? In order to address these and other questions, we have developed a rate-based model of a post-combustion CO₂ capture process using micro-encapsulated ILs. As a performance baseline

S-factor for radiative capture reactions for light nuclei at astrophysical energies

Science.gov (United States)

Ghasemi, Reza; Sadeghi, Hossein

2018-06-01

The astrophysical S-factors of thermonuclear reactions, including radiative capture reactions and their analysis in the frame of different theoretical models, are the main source of nuclear processes. We have done research on the radiative capture reactions importance in the framework of a potential model. Investigation of the reactions in the astrophysical energies is of great interest in the aspect of astrophysics and nuclear physics for developing correct models of burning and evolution of stars. The experimental measurements are very difficult and impossible because of these reactions occurrence at low-energies. In this paper we do a calculation on radiative capture astrophysical S-factors for nuclei in the mass region A theoretical methods.

Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry in the identification of organic compounds in atmospheric aerosols from coniferous forest

NARCIS (Netherlands)

Kallio, M.; Jussila, M.; Rissanen, T.; Anttila, P.; Hartonen, K.; Reissell, A.; Vreuls, R.J.J.; Adahchour, M.; Hyotylainen, T.

2006-01-01

Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOF-MS) was applied in the identification of organic compounds in atmospheric aerosols from coniferous forest. The samples were collected at Hyytiälä, Finland, as part of the QUEST campaign, in

Capture and exploration of sample quality data to inform and improve the management of a screening collection.

Science.gov (United States)

Charles, Isabel; Sinclair, Ian; Addison, Daniel H

2014-04-01

A new approach to the storage, processing, and interrogation of the quality data for screening samples has improved analytical throughput and confidence and enhanced the opportunities for learning from the accumulating records. The approach has entailed the design, development, and implementation of a database-oriented system, capturing information from the liquid chromatography-mass spectrometry capabilities used for assessing the integrity of samples in AstraZeneca's screening collection. A Web application has been developed to enable the visualization and interactive annotation of the analytical data, monitor the current sample queue, and report the throughput rate. Sample purity and identity are certified automatically on the chromatographic peaks of interest if predetermined thresholds are reached on key parameters. Using information extracted in parallel from the compound registration and container inventory databases, the chromatographic and spectroscopic profiles for each vessel are linked to the sample structures and storage histories. A search engine facilitates the direct comparison of results for multiple vessels of the same or similar compounds, for single vessels analyzed at different time points, or for vessels related by their origin or process flow. Access to this network of information has provided a deeper understanding of the multiple factors contributing to sample quality assurance.

Mass spectrometry-driven drug discovery for development of herbal medicine.

Science.gov (United States)

Zhang, Aihua; Sun, Hui; Wang, Xijun

2018-05-01

Herbal medicine (HM) has made a major contribution to the drug discovery process with regard to identifying products compounds. Currently, more attention has been focused on drug discovery from natural compounds of HM. Despite the rapid advancement of modern analytical techniques, drug discovery is still a difficult and lengthy process. Fortunately, mass spectrometry (MS) can provide us with useful structural information for drug discovery, has been recognized as a sensitive, rapid, and high-throughput technology for advancing drug discovery from HM in the post-genomic era. It is essential to develop an efficient, high-quality, high-throughput screening method integrated with an MS platform for early screening of candidate drug molecules from natural products. We have developed a new chinmedomics strategy reliant on MS that is capable of capturing the candidate molecules, facilitating their identification of novel chemical structures in the early phase; chinmedomics-guided natural product discovery based on MS may provide an effective tool that addresses challenges in early screening of effective constituents of herbs against disease. This critical review covers the use of MS with related techniques and methodologies for natural product discovery, biomarker identification, and determination of mechanisms of action. It also highlights high-throughput chinmedomics screening methods suitable for lead compound discovery illustrated by recent successes. © 2016 Wiley Periodicals, Inc.

Supercritical fluid chromatography coupled with in-source atmospheric pressure ionization hydrogen/deuterium exchange mass spectrometry for compound speciation.

Science.gov (United States)

Cho, Yunju; Choi, Man-Ho; Kim, Byungjoo; Kim, Sunghwan

2016-04-29

An experimental setup for the speciation of compounds by hydrogen/deuterium exchange (HDX) with atmospheric pressure ionization while performing chromatographic separation is presented. The proposed experimental setup combines the high performance supercritical fluid chromatography (SFC) system that can be readily used as an inlet for mass spectrometry (MS) and atmospheric pressure photo ionization (APPI) or atmospheric pressure chemical ionization (APCI) HDX. This combination overcomes the limitation of an approach using conventional liquid chromatography (LC) by minimizing the amount of deuterium solvents used for separation. In the SFC separation, supercritical CO2 was used as a major component of the mobile phase, and methanol was used as a minor co-solvent. By using deuterated methanol (CH3OD), AP HDX was achieved during SFC separation. To prove the concept, thirty one nitrogen- and/or oxygen-containing standard compounds were analyzed by SFC-AP HDX MS. The compounds were successfully speciated from the obtained SFC-MS spectra. The exchange ions were observed with as low as 1% of CH3OD in the mobile phase, and separation could be performed within approximately 20min using approximately 0.24 mL of CH3OD. The results showed that SFC separation and APPI/APCI HDX could be successfully performed using the suggested method. Copyright © 2016 Elsevier B.V. All rights reserved.

Boron-containing thioureas for neutron capture therapy

International Nuclear Information System (INIS)

Ketz, H.

1993-01-01

Melanin is produced in large amounts in malignant melanotic melanomas. Because thiourea compounds are covalently incorporated into melanin during its biosynthesis, the preparation of boronated thiourea-derivatives is of particular interest for the BNCT (Boron Neutron Capture Therapy). Accumulation of boron in tumors by means of boronated thiourea-derivatives may therefore provide levels of 10 B which are useful for BNCT. In BNCT the tumor containing the boron compound is irradiated with epithermal neutrons to generate He- and Li-nuclei from the 10 B which can then destroy the tumor cells. Because of the short ranges of these particles (approximately one cell diameter) the damage will be almost exclusively confined to the tumor leaving normal tissue unharmed. High accumulation of 2-mercapto-1-methylimidazole (methimazole) in melanotic melanomas has been described in the literature. Boronated derivatives of methimazole were therefore synthesized. Boron was in the form of a boronic acid, a nido-carbonate and a mercaptoundeca hydro-closo-dodecaborate (BSH). The synthesis of the boron cluster derivatives of methimazole (nido-carborate- and BSH-derivatives) with 9 resp. 12 boron atoms in the molecule were expected to achieve higher concentrations of boron in the tumor than in the case of the boronic acid compound with its single boron atom. (orig.) [de

Influence of wetting-layer wave functions on phonon-mediated carrier capture into self-assembled quantum dots

DEFF Research Database (Denmark)

Markussen, Troels; Kristensen, Philip Trøst; Tromborg, Bjarne

2006-01-01

Models of carrier dynamics in quantum dots rely strongly on adequate descriptions of the carrier wave functions. In this work we numerically solve the one-band effective mass Schrodinger equation to calculate the capture times of phonon-mediated carrier capture into self-assembled quantum dots. C....... Comparing with results obtained using approximate carrier wave functions, we demonstrate that the capture times are strongly influenced by properties of the wetting layer wave functions not accounted for by earlier theoretical analyses....

Near-Ultraviolet Observations of CS 29497-030: New Constraints on Neutron-Capture Nucleosynthesis Processes

Science.gov (United States)

Ivans, Inese I.; Sneden, Christopher; Gallino, Roberto; Cowan, John J.; Preston, George W.

2005-07-01

Employing spectra obtained with the new Keck I HIRES near-UV-sensitive detector, we have performed a comprehensive chemical composition analysis of the binary blue metal-poor star CS 29497-030. Abundances for 29 elements and upper limits for an additional seven have been derived, concentrating on elements largely produced by means of neutron-capture nucleosynthesis. Included in our analysis are the two elements that define the termination point of the slow neutron-capture process, lead and bismuth. We determine an extremely high value of [Pb/Fe]=+3.65+/-0.07 (σ=0.13) from three features, supporting the single-feature result obtained in previous studies. We detect Bi for the first time in a metal-poor star. Our derived Bi/Pb ratio is in accord with those predicted from the most recent FRANEC calculations of the slow neutron-capture process in low-mass asymptotic giant branch (AGB) stars. We find that the neutron-capture elemental abundances of CS 29497-030 are best explained by an AGB model that also includes very significant amounts of pre-enrichment of rapid neutron-capture process material in the protostellar cloud out of which the CS 29497-030 binary system formed. Mass transfer is consistent with the observed [Nb/Zr]~0. Thus, CS 29497-030 is both an r+s and ``extrinsic AGB'' star. Furthermore, we find that the mass of the AGB model can be further constrained by the abundance of the light odd-element Na. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

ANALYSIS AND IDENTIFICATION SPIKING CHEMICAL COMPOUNDS RELATED TO CHEMICAL WEAPON CONVENTION IN UNKNOWN WATER SAMPLES USING GAS CHROMATOGRAPHY AND GAS CHROMATOGRAPHY ELECTRON IONIZATION MASS SPECTROMETRY

Directory of Open Access Journals (Sweden)

Harry Budiman

2010-06-01

Full Text Available The identification and analysis of chemical warfare agents and their degradation products is one of important component for the implementation of the convention. Nowadays, the analytical method for determination chemical warfare agent and their degradation products has been developing and improving. In order to get the sufficient analytical data as recommended by OPCW especially in Proficiency Testing, the spiking chemical compounds related to Chemical Weapon Convention in unknown water sample were determined using two different techniques such as gas chromatography and gas chromatography electron-impact ionization mass spectrometry. Neutral organic extraction, pH 11 organic extraction, cation exchanged-methylation, triethylamine/methanol-silylation were performed to extract the chemical warfare agents from the sample, before analyzing with gas chromatography. The identification of chemical warfare agents was carried out by comparing the mass spectrum of chemicals with mass spectrum reference from the OPCW Central Analytical Database (OCAD library while the retention indices calculation obtained from gas chromatography analysis was used to get the confirmation and supported data of  the chemical warfare agents. Diisopropyl methylphosphonate, 2,2-diphenyl-2-hydroacetic acid and 3-quinuclidinol were found in unknown water sample. Those chemicals were classified in schedule 2 as precursor or reactant of chemical weapons compound in schedule list of Chemical Weapon Convention.   Keywords: gas chromatography, mass spectrometry, retention indices, OCAD library, chemical warfare agents

Direct introduction of volatile carbon compounds into the spray chamber of an inductively coupled plasma mass spectrometer: Sensitivity enhancement for selenium

International Nuclear Information System (INIS)

Kovacevic, Miroslav; Goessler, Walter

2005-01-01

The effect of signal enhancement of elements with ionization potentials in the range from 9 to 11 eV by carbon-containing compounds is a well-known phenomenon in inductively coupled plasma mass spectrometry (ICPMS). It has traditionally been exploited through the addition of organic solvents to the sample matrix or to the mobile phase to improve sensitivity. In the present work, aqueous solutions of volatile carbon compounds (acetone, methanol and acetic acid) were directly introduced into the thermostatted spray chamber rather than being added to the sample matrix. It is presumed that no aerosol is produced from these solutions and only vapors of organic compounds are swept into the plasma together with the sample aerosol. When a 0.40 mol l -1 aqueous solution of acetone was introduced directly into the spray chamber, the signals for arsenic and selenium were enhanced by a factor of 4.2. The usefulness of this approach was demonstrated through the achievement of lower instrumental detection limits for selenium at m/z 82 (0.1 ng ml -1 ) compared to the system without direct introduction of volatile carbon compounds (0.5 ng ml -1 ). The method was successfully applied in the determination of traces of selenium in natural water, urine and bovine liver reference material

Development of a fast liquid chromatography-tandem mass spectrometry method for the determination of endocrine-disrupting compounds in waters.

Science.gov (United States)

Di Carro, Marina; Scapolla, Carlo; Liscio, Camilla; Magi, Emanuele

2010-09-01

A fast liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS-MS) method was developed to study five endocrine-disrupting compounds (4-n-nonylphenol, bisphenol A, estrone, 17β-estradiol and 17α-ethinylestradiol) in water. Different columns were tested; the chromatographic separation of the analytes was optimized on a Pinnacle DB biphenylic column with a water-acetonitrile gradient elution, which allowed the separation of the selected endocrine-disrupting compounds (EDCs) in less than 6 min. Quantitative analysis was performed in selected reaction monitoring (SRM) mode; two transitions were chosen for each compound, using the most abundant for quantitation. Calibration curves using bisphenol A-d (16) as internal standard were drawn, showing good correlation coefficients (0.9993-0.9998). All figures of merit of the method were satisfactory; limits of detection were in the low pg range for all analytes. The method was then applied to the determination of the analytes in real water samples: to this aim, polar organic chemical integrative samplers (POCIS) were deployed in the influent and in the effluent of a drinking water treatment plant in Liguria (Italy). The EDC level was rather low in the influent and negligible in the outlet, reflecting the expected function of the treatment plant.

Bipolar Mass Spectrometry of Labile Coordination Complexes, Redox Active Inorganic Compounds, and Proteins Using a Glass Nebulizer for Sonic-Spray Ionization

Science.gov (United States)

Antonakis, Manolis M.; Tsirigotaki, Alexandra; Kanaki, Katerina; Milios, Constantinos J.; Pergantis, Spiros A.

2013-08-01

In this study, we report on the development of a novel nebulizer configuration for sonic-spray ionization (SSI) mass spectrometry (MS), more specifically for a version of SSI that is referred to as Venturi easy ambient sonic-spray ionization (V-EASI) MS. The developed nebulizer configuration is based on a commercially available pneumatic glass nebulizer that has been used extensively for aerosol formation in atomic spectrometry. In the present study, the nebulizer was modified in order to achieve efficient V-EASI-MS operation. Upon evaluating this system, it has been demonstrated that V-EASI-MS offers some distinct advantages for the analysis of coordination compounds and redox active inorganic compounds over the predominantly used electrospray ionization (ESI) technique. Such advantages, for this type of compounds, are demonstrated here for the first time. More specifically, a series of labile heptanuclear heterometallic [CuII 6LnIII] clusters held together with artificial amino acid ligands, in addition to easily oxidized inorganic oxyanions of selenium and arsenic, were analyzed. The observed advantages pertain to V-EASI appearing to be a "milder" ionization source than ESI, not requiring electrical potentials for gas phase ion formation, thus eliminating the possibility of unwanted redox transformations, allowing for the "simultaneous" detection of negative and positive ions (bipolar analysis) without the need to change source ionization conditions, and also not requiring the use of syringes and delivery pumps. Because of such features, especially because of the absence of ionization potentials, EASI can be operated with minimal requirements for source parameter optimization. We observed that source temperature and accelerating voltage do not seem to affect labile compounds to the extent they do in ESI-MS. In addition, bipolar analysis of proteins was demonstrated here by acquiring both positive and negative ion mass spectra from the same protein solutions

Determination of volatile compounds in four commercial samples of Japanese green algae using solid phase microextraction gas chromatography mass spectrometry.

Science.gov (United States)

Yamamoto, Masayoshi; Baldermann, Susanne; Yoshikawa, Keisuke; Fujita, Akira; Mase, Nobuyuki; Watanabe, Naoharu

2014-01-01

Green algae are of great economic importance. Seaweed is consumed fresh or as seasoning in Japan. The commercial value is determined by quality, color, and flavor and is also strongly influenced by the production area. Our research, based on solid phase microextraction gas chromatography mass spectrometry (SPME-GC-MS), has revealed that volatile compounds differ intensely in the four varieties of commercial green algae. Accordingly, 41 major volatile compounds were identified. Heptadecene was the most abundant compound from Okayama (Ulva prolifera), Tokushima (Ulva prolifera), and Ehime prefecture (Ulva linza). Apocarotenoids, such as ionones, and their derivatives were prominent volatiles in algae from Okayama (Ulva prolifera) and Tokushima prefecture (Ulva prolifera). Volatile, short chained apocarotenoids are among the most potent flavor components and contribute to the flavor of fresh, processed algae, and algae-based products. Benzaldehyde was predominant in seaweed from Shizuoka prefecture (Monostroma nitidum). Multivariant statistical analysis (PCA) enabled simple discrimination of the samples based on their volatile profiles. This work shows the potential of SPME-GC-MS coupled with multivariant analysis to discriminate between samples of different geographical and botanical origins and form the basis for development of authentication methods of green algae products, including seasonings.

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

Science.gov (United States)

Hu, Weiwei; Campuzano-Jost, Pedro; Day, Douglas A.; Croteau, Philip; Canagaratna, Manjula R.; Jayne, John T.; Worsnop, Douglas R.; Jimenez, Jose L.

2017-08-01

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. A new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH4NO3, NaNO3, (NH4)2SO4 and NH4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (Tv ˜ 200-800 °C) on the detected fragments, CE and size distributions are investigated. A Tv of 500-550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH4NO3) and comparable to or higher than the SV for less-volatile species (e.g. (NH4)2SO4), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO3 and SO4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO2(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH4NO3 and comparable to the SV for NaNO3. . We observe an extremely consistent fragmentation for ammonium compared to very large changes for the

Mass spectrometry in grape and wine chemistry. Part II: The consumer protection.

Science.gov (United States)

Flamini, Riccardo; Panighel, Annarita

2006-01-01

Controls in food industry are fundamental to protect the consumer health. For products of high quality, warranty of origin and identity is required and analytical control is very important to prevent frauds. In this article, the "state of art" of mass spectrometry in enological chemistry as a consumer safety contribute is reported. Gas chromatography-mass spectrometry (GC/MS) and liquid-chromatography-mass spectrometry (LC/MS) methods have been developed to determine pesticides, ethyl carbamate, and compounds from the yeast and bacterial metabolism in wine. The presence of pesticides in wine is mainly linked to the use of dicarboxyimide fungicides on vineyard shortly before the harvest to prevent the Botrytis cinerea attack of grape. Pesticide residues are regulated at maximum residue limits in grape of low ppm levels, but significantly lower levels in wine have to be detected, and mass spectrometry offers effective and sensitive methods. Moreover, mass spectrometry represent an advantageous alternative to the radioactive-source-containing electron capture detector commonly used in GC analysis of pesticides. Analysis of ochratoxin A (OTA) in wine by LC/MS and multiple mass spectrometry (MS/MS) permits to confirm the toxin presence without the use of expensive immunoaffinity columns, or time and solvent consuming sample derivatization procedures. Inductively coupled plasma-mass spectrometry (ICP/MS) is used to control heavy metals contamination in wine, and to verify the wine origin and authenticity. Isotopic ratio-mass spectrometry (IRMS) is applied to reveal wine watering and sugar additions, and to determine the product origin and traceability.

Standard test method for determination of impurities in nuclear grade uranium compounds by inductively coupled plasma mass spectrometry

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This test method covers the determination of 67 elements in uranium dioxide samples and nuclear grade uranium compounds and solutions without matrix separation by inductively coupled plasma mass spectrometry (ICP-MS). The elements are listed in Table 1. These elements can also be determined in uranyl nitrate hexahydrate (UNH), uranium hexafluoride (UF6), triuranium octoxide (U3O8) and uranium trioxide (UO3) if these compounds are treated and converted to the same uranium concentration solution. 1.2 The elements boron, sodium, silicon, phosphorus, potassium, calcium and iron can be determined using different techniques. The analyst's instrumentation will determine which procedure is chosen for the analysis. 1.3 The test method for technetium-99 is given in Annex A1. 1.4 The values stated in SI units are to be regarded as standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish ...

Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: mass balance, PCR and compound-specific stable isotope analysis.

OpenAIRE

Courbet Christelle; Rivière Agnès; Jeannottat Simon; Rinaldi Sandro; Hunkeler Daniel; Bendjoudi Hocine; De Marsily Ghislain

2011-01-01

This work describes the use of different complementing methods (mass balance polymerase chain reaction assays and compound specific stable isotope analysis) to demonstrate the existence and effectiveness of biodegradation of chlorinated solvents in an alluvial aquifer. The solvent contaminated site is an old chemical factory located in an alluvial plain in France. As most of the chlorinated contaminants currently found in the groundwater at this site were produced by local industries at vario...

Analysis of volatile compounds of Malaysian Tualang ( Koompassia ...

African Journals Online (AJOL)

Analysis of volatile compounds of Malaysian Tualang ( Koompassia excelsa ) honey using gas chromatography mass spectrometry. ... Other classes of chemical compounds detected included acids, aldehydes, alcohols, ketones, terpenes, furans and a miscellaneous group. Methanol yielded the highest number of extracted ...

Determination of quaternary ammonium compounds in seawater samples by solid-phase extraction and liquid chromatography-mass spectrometry.

Science.gov (United States)

Bassarab, P; Williams, D; Dean, J R; Ludkin, E; Perry, J J

2011-02-04

A method for the simultaneous determination of two biocidal quaternary ammonium compounds; didecyldimethylammonium chloride (didecyldimethyl quat) and dodecylbenzyldimethylammonium chloride (benzyl quat), in seawater by solid phase extraction (SPE) followed by liquid chromatography-mass spectrometry (LC-MS) was developed. The optimised procedure utilised off-line extraction of the analytes from seawater using polymeric (Strata-X) SPE cartridges. Recoveries ranged from 80 to 105%, with detection limits at the low parts-per-trillion (ng/l) level for both analytes. To demonstrate sensitivity, environmental concentrations were measured at three different locations along the North East coast of England with measured values in the range 120-270ng/l. Copyright © 2010 Elsevier B.V. All rights reserved.

Assessment of a combined gas chromatography mass spectrometer sensor (GC-MSS) system for detecting biologically relevant volatile compounds (VCs).

Science.gov (United States)

Gould, Oliver; Wieczorek, Tomas; de Lacy Costello, Ben P J; Persad, Raj; Ratcliffe, Norman

2017-09-26

There have been a number of studies in which metal oxide sensors (MOS) have replaced conventional analytical detectors in gas chromatography systems. However, despite the use of these instruments in a range of applications including breath research the sensor responses (i.e. resistance changes w.r.t. concentration of VCs) remain largely unreported. This paper addresses that issue by comparing the response of a metal oxide sensor directly with a mass spectrometer (MS), whereby both detectors are interfaced to the same GC column using an s-swafer. It was demonstrated that the sensitivity of an in-house fabricated ZnO/ SnO2 thick film MOS was superior to a modern MS for the detection of a wide range of volatile compounds (VCs) of different functionalities and masses. Better techniques for detection and quantification of these VCs is valuable, as many of these compounds are commonly reported throughout the scientific literature. This is also the first published report of a combined GC-MS sensor system. These 2 different detector technologies when combined, should enhance discriminatory abilities to aid disease diagnoses using volatiles from e.g. breath, and bodily fluids. 29 chemical standards have been tested using solid phase micro-extraction; 25 of these compounds are found on human breath. In all but 2 instances the sensor exhibited the same or superior limit of detection compared to the MS. 12 stool samples from healthy participants were analysed, the sensor detected, on average 1.6 peaks more per sample than the MS. Similarly analysing the headspace of E. coli broth cultures the sensor detected 6.9 more peaks per sample versus the MS. This greater sensitivity is primarily a function of the superior limits of detection of the metal oxide sensor. This shows that systems based on the combination of chromatography systems with solid state sensors shows promise for a range of applications. © 2017 IOP Publishing Ltd.

Natural compounds involved in adipose tissue mass control in in vitro studies

Directory of Open Access Journals (Sweden)

Katarzyna Kowalska

2011-08-01

Full Text Available The World Health Organization (WHO has recognized obesity as an epidemic of the 21st century. Obesity is pathological fat accumulation in the body influenced by many factors: metabolic, endocrine, genetic, environmental, psychological and behavioral. The quality and quantity of food intake to a considerable degree determine excessive fat accumulation in the body. The strategy in obesity prevention includes, among other things, a proper diet. It is widely known that a diet rich in fruits and vegetables reduces body weight. Adipocytes are not only cells serving as storage depots for “energy”, but are also specialized cells influenced by various hormones, cytokines and nutrients, which have pleiotropic effects on the body. Knowledge of adipocyte biology is crucial for our understanding of the pathophysiological basis of obesity and metabolic diseases, such as type 2 diabetes. Furthermore, rational manipulation of adipose physiology is a promising avenue for therapy of these conditions. Adipose tissue mass can be reduced through elimination of adipocytes by apoptosis, inhibition of adipogenesis and increased lipolysis in adipocytes. Natural products have a potential to induce apoptosis, inhibit adipogenesis and stimulate lipolysis in adipocytes. Various dietary bioactive compounds target different stages of the adipocyte life cycle and may be useful as natural therapeutic agents in obesity prevention.

The masses of nobelium and lawrencium isotopes, the mass difference between {sup 180}W and {sup 180}Hf, and a characterization of the future cryogenic stopping cell of the online mass spectrometer SHIPTRAP

Energy Technology Data Exchange (ETDEWEB)

Droese, Christian

2015-01-29

This work describes the recent scientific and technical achievements obtained at the high-precision Penning trap mass spectrometer SHIPTRAP. The scientific focus of the SHIPTRAP experiment are mass measurements of short-lived nuclides with proton number larger than 100. The masses of these isotopes are usually determined via extrapolations, systematic trends, predictions based on theoretical models or alpha-decay spectroscopy. In several experiments the masses of the isotopes {sup 252-255}No and {sup 255,256}Lr have been measured directly. With the obtained results the region of enhanced nuclear stability at the deformed shell closure at the neutron number 152 was investigated. Furthermore, the masses have been used to benchmark theoretical mass models. The measured masses were compared selected mass models which revealed differences between few keV/c² up to several MeV/c² depending on the investigated nuclide and model. In order to perform mass measurements on superheavy nuclei with lower production rates, the efficiency of the SHIPTRAP setup needs to be increased. Currently, the efficiency is 2% and mainly limited by the stopping- and extraction efficiency of the buffer gas cell. The stopping and extraction efficiency of the current buffer gas cell is 12%. To this end, a modified version of the buffer gas cell was developed and characterized with {sup 223}Ra ion source. Besides a larger stopping volume and a coaxial injection the new buffer gas cell is operated at a temperature of 40 K. The operation at cryogenic temperatures increases the cleanliness of the buffer gas. From extraction measurements and simulations an overall efficiency of 62(3)% was determined which results in an increase by a factor of 5 in comparison to the current buffer gas cell. Aside from high-precision mass measurements of heavy radionuclides the mass differences of metastable isobars was measured to identify candidates for the neutrinoless double-electron capture. Neutrinoless double

Environmental Chemistry Compound Identification Using High ...

Science.gov (United States)

There is a growing need for rapid chemical screening and prioritization to inform regulatory decision-making on thousands of chemicals in the environment. We have previously used high-resolution mass spectrometry to examine household vacuum dust samples using liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS). Using a combination of exact mass, isotope distribution, and isotope spacing, molecular features were matched with a list of chemical formulas from the EPA’s Distributed Structure-Searchable Toxicity (DSSTox) database. This has further developed our understanding of how openly available chemical databases, together with the appropriate searches, could be used for the purpose of compound identification. We report here on the utility of the EPA’s iCSS Chemistry Dashboard for the purpose of compound identification using searches against a database of over 720,000 chemicals. We also examine the benefits of QSAR prediction for the purpose of retention time prediction to allow for alignment of both chromatographic and mass spectral properties. This abstract does not reflect U.S. EPA policy presentation at the Eastern Analytical Symposium.

Fission before mass equilibration in heavy ion reactions

International Nuclear Information System (INIS)

Yadav, C.; Thomas, R.G.; Mohanty, A.K.

2013-01-01

For compound nucleus (CN) fission, it is expected that the width of the fragment mass distribution is independent of the entrance channel. In quasifission reaction, however, recent experiments reported anomalous broadening of mass distribution for more symmetric systems forming the same compound nucleus in fissile (fissility ∼ 0.8) and less fissile (fissility ∼ 0.7) systems. These measurements have not shown any mass-angle correlation, but width of fission fragment mass distribution was found to be consistently higher than that expected for fusion-fission

Mass flows of perfluorinated compounds (PFCs) in central wastewater treatment plants of industrial zones in Thailand.

Science.gov (United States)

Kunacheva, Chinagarn; Tanaka, Shuhei; Fujii, Shigeo; Boontanon, Suwanna Kitpati; Musirat, Chanatip; Wongwattana, Thana; Shivakoti, Binaya Raj

2011-04-01

Perfluorinated compounds (PFCs) are fully fluorinated organic compounds, which have been used in many industrial processes and have been detected in wastewater and sludge from municipal wastewater treatment plants (WWTPs) around the world. This study focused on the occurrences of PFCs and PFCs mass flows in the industrial wastewater treatment plants, which reported to be the important sources of PFCs. Surveys were conducted in central wastewater treatment plant in two industrial zones in Thailand. Samples were collected from influent, aeration tank, secondary clarifier effluent, effluent and sludge. The major purpose of this field study was to identify PFCs occurrences and mass flow during industrial WWTP. Solid-phase extraction (SPE) coupled with HPLC-ESI-MS/MS were used for the analysis. Total 10 PFCs including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluoropropanoic acid (PFPA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorohexane sulfonate (PFHxS), perfluoronanoic acid (PFNA), perfluordecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA) were measured to identify their occurrences. PFCs were detected in both liquid and solid phase in most samples. The exceptionally high level of PFCs was detected in the treatment plant of IZ1 and IZ2 ranging between 662-847ngL(-1) and 674-1383ngL(-1), respectively, which greater than PFCs found in most domestic wastewater. Due to PFCs non-biodegradable property, both WWTPs were found ineffective in removing PFCs using activated sludge processes. Bio-accumulation in sludge could be the major removal mechanism of PFCs in the process. The increasing amount of PFCs after activated sludge processes were identified which could be due to the degradation of PFCs precursors. PFCs concentration found in the effluent were very high comparing to those in river water of the area. Industrial activity could be the one of major sources of PFCs

Analyses of Indole Compounds in Sugar Cane (Saccharum officinarum L. Juice by High Performance Liquid Chromatography and Liquid Chromatography-Mass Spectrometry after Solid-Phase Extraction

Directory of Open Access Journals (Sweden)

Jean Wan Hong Yong

2017-03-01

Full Text Available Simultaneous quantitative analysis of 10 indole compounds, including indole-3-acetic acid (IAA, one of the most important naturally occurring auxins and some of its metabolites, by high performance liquid chromatography (HPLC and liquid chromatography-mass spectrometry (LC-MS after solid-phase extraction (SPE was reported for the first time. The analysis was carried out using a reverse phase HPLC gradient elution, with an aqueous mobile phase (containing 0.1% formic acid modified by methanol. Furthermore, a novel SPE procedure was developed for the pre-concentration and purification of indole compounds using C18 SPE cartridges. The combination of SPE, HPLC, and LC-MS was applied to screen for the indole compounds present in sugar cane (Saccharum officinarum L. juice, a refreshing beverage with various health benefits. Finally, four indole compounds were successfully detected and quantified in sugar cane juice by HPLC, which were further unequivocally confirmed by LC-MS/MS experiments operating in the multiple reaction monitoring (MRM mode.

Ultra-high performance liquid chromatography coupled to mass spectrometry applied to the identification of valuable phenolic compounds from Eucalyptus wood.

Science.gov (United States)

Santos, Sónia A O; Vilela, Carla; Freire, Carmen S R; Neto, Carlos Pascoal; Silvestre, Armando J D

2013-11-01

Ultra-high performance liquid chromatography (UHPLC) was applied for the first time in the analysis of wood extracts. The potential of this technique coupled to ion trap mass spectrometry in the rapid and effective detection and identification of bioactive components in complex vegetal samples was demonstrated. Several dozens of compounds were detected in less than 30min of analysis time, corresponding to more than 3-fold reduction in time, when compared to conventional HPLC analysis of similar extracts. The phenolic chemical composition of Eucalyptus grandis, Eucalyptus urograndis (E. grandis×E. urophylla) and Eucalyptus maidenii wood extracts was assessed for the first time, with the identification of 51 phenolic compounds in the three wood extracts. Twenty of these compounds are reported for the first time as Eucalyptus genus components. Ellagic acid and ellagic acid-pentoside are the major components in all extracts, followed by gallic and quinic acids in E. grandis and E. urograndis and ellagic acid-pentoside isomer, isorhamnetin-hexoside and gallic acid in E. maidenii. The antioxidant scavenging activity of the extracts was evaluated, with E. grandis wood extract showing the lowest IC50 value. Moreover, the antioxidant activity of these extracts was higher than that of the commercial antioxidant BHT and of those of the corresponding bark extracts. These results, together with the phenolic content values, open good perspectives for the exploitation of these renewable resources as a source of valuable phenolic compounds. Copyright © 2013 Elsevier B.V. All rights reserved.

In vivo genotoxicity of nitramines, transformation products of amine-based carbon capture technology

Directory of Open Access Journals (Sweden)

Claire Coutris

2015-05-01

Full Text Available In times where we need to reduce our CO2 emissions to the atmosphere, it is important to get a clearer picture of the environmental impacts associated with potential mitigation technologies. Chemical absorption with amines is emerging as the most advanced mitigation technology for post-combustion capture of CO2 from fossil fuel power stations. Although the amine solvent used in this technology is recycled during the capture process, degradation products are formed and released into the environment. Among these degradation products, the aliphatic nitramine compounds dimethylnitramine and ethanolnitramine have been identified, whose environmental impact was unknown. In addition to conducting survival, growth and reproduction tests in a range of marine species, we looked into the in vivo genotoxic potential of these two compounds to experimentally exposed fish (Coutris et al. 2015. DNA damage was analyzed in blood samples collected from the caudal vein of juvenile turbot Scophthalmus maximus after 28 day exposure to nitramines, using the 12 mini-gels version of the comet assay, with and without digestion with formamidopyrimidine DNA glycosylase. Although whole organism bioassays indicated that nitramine toxicity through necrosis was low, the genotoxicity assessment revealed contrasting results, with ethanolnitramine found to be more genotoxic than dimethylnitramine by three orders of magnitude. At the lowest ethanolnitramine concentration (1 mg/L, 84 % DNA damage was observed, whereas 100 mg/L dimethylnitramine was required to cause 37 % DNA damage. The mechanisms of genotoxicity were also shown to differ between the two compounds, with oxidation of the DNA bases responsible for over 90 % of the genotoxicity of dimethylnitramine, whereas DNA strand breaks and alkali-labile sites were responsible for over 90 % of the genotoxicity of ethanolnitramine. Fish exposed to > 3 mg/L ethanolnitramine had virtually no DNA left in their red blood cells. The

Optional carbon capture

Energy Technology Data Exchange (ETDEWEB)

Alderson, T.; Scott, S.; Griffiths, J. [Jacobs Engineering, London (United Kingdom)

2007-07-01

In the case of IGCC power plants, carbon capture can be carried out before combustion. The carbon monoxide in the syngas is catalytically shifted to carbon dioxide and then captured in a standard gas absorption system. However, the insertion of a shift converter into an existing IGCC plant with no shift would mean a near total rebuild of the gasification waste heat recovery, gas treatment system and HRSG, with only the gasifier and gas turbine retaining most of their original features. To reduce the extent, cost and time taken for the revamping, the original plant could incorporate the shift, and the plant would then be operated without capture to advantage, and converted to capture mode of operation when commercially appropriate. This paper examines this concept of placing a shift converter into an IGCC plant before capture is required, and operating the same plant first without and then later with CO{sub 2} capture in a European context. The advantages and disadvantages of this 'capture ready' option are discussed. 6 refs., 2 figs., 4 tabs.

Dose modification factors in boron neutron capture therapy

Energy Technology Data Exchange (ETDEWEB)

Allen, B.J. (Australian Nuclear Science and Technology Organization (ANSTO), Menai (Australia))

1993-01-01

The effective treatment depth and therapeutic ratio in boron neutron capture therapy (BNCT) depend on a number of macroscopic dose factors such as boron concentrations in the tumor, normal tissue and blood. However, the role of various microscopic dose modification factors can be of critical importance in the evaluation of normal tissue tolerance levels. An understanding of these factors is valuable in designing BNCT experiments and the selection of appropriate boron compounds. These factors are defined in this paper and applied to the case of brain tumors with particular attention to capillary endothelial cells and oligodendrocytes. (orig.).

Hydrogen fluoride capture by imidazolium acetate ionic liquid

Science.gov (United States)

Chaban, Vitaly

2015-04-01

Extraction of hydrofluoric acid (HF) from oils is a drastically important problem in petroleum industry, since HF causes quick corrosion of pipe lines and brings severe health problems to humanity. Some ionic liquids (ILs) constitute promising scavenger agents thanks to strong binding to polar compounds and tunability. PM7-MD simulations and hybrid density functional theory are employed here to consider HF capture ability of ILs. Discussing the effects and impacts of the cation and the anion separately and together, we evaluate performance of imidazolium acetate and outline systematic search guidelines for efficient adsorption and extraction of HF.

Use of Proton-Transfer-Reaction Mass Spectrometry to Characterize Volatile Organic Compound Sources at the La Porte Super Site During the Texas Air Quality Study 2000

Energy Technology Data Exchange (ETDEWEB)

Karl, Thomas G.; Jobson, B Tom T.; Kuster, W. C.; Williams, Eric; Stutz, Jochen P.; Shetter, Rick; Hall, Samual R.; Goldan, P. D.; Fehsenfeld, Fred C.; Lindinger, Werner

2003-08-19

Proton-transfer-reaction mass spectrometry (PTR-MS) was deployed for continuous real-time monitoring of volatile organic compounds (VOCs) at a site near the Houston Ship Channel during the Texas Air Quality Study 2000. Overall, 28 ions dominated the PTR-MS mass spectra and were assigned as anthropogenic aromatics (e.g., benzene, toluene, xylenes) and hydrocarbons (propene, isoprene), oxygenated compounds (e.g., formaldehyde, acetaldehyde, acetone, methanol, C7 carbonyls), and three nitrogencontaining compounds (e.g., HCN, acetonitrile and acrylonitrile). Biogenic VOCs were minor components at this site. Propene was the most abundant lightweight hydrocarbon detected by this technique with concentrations up to 100+ nmol mol-1, and was highly correlated with its oxidation products, formaldehyde (up to ~40 nmol mol-1) and acetaldehyde (up to ~80 nmol/mol), with typical ratios close to 1 in propene-dominated plumes. In the case of aromatic species the high time resolution of the obtained data set helped in identifying different anthropogenic sources (e.g., industrial from urban emissions) and testing current emission inventories. A comparison with results from complimentary techniques (gas chromatography, differential optical absorption spectroscopy) was used to assess the selectivity of this on-line technique in a complex urban and industrial VOC matrix and give an interpretation of mass scans obtained by ‘‘soft’’ chemical ionization using proton-transfer via H3O+. The method was especially valuable in monitoring rapidly changing VOC plumes which passed over the site, and when coupled with meteorological data it was possible to identify likely sources.

Computer modeling the boron compound factor in normal brain tissue

International Nuclear Information System (INIS)

Gavin, P.R.; Huiskamp, R.; Wheeler, F.J.; Griebenow, M.L.

1993-01-01

The macroscopic distribution of borocaptate sodium (Na 2 B 12 H 11 SH or BSH) in normal tissues has been determined and can be accurately predicted from the blood concentration. The compound para-borono-phenylalanine (p-BPA) has also been studied in dogs and normal tissue distribution has been determined. The total physical dose required to reach a biological isoeffect appears to increase directly as the proportion of boron capture dose increases. This effect, together with knowledge of the macrodistribution, led to estimates of the influence of the microdistribution of the BSH compound. This paper reports a computer model that was used to predict the compound factor for BSH and p-BPA and, hence, the equivalent radiation in normal tissues. The compound factor would need to be calculated for other compounds with different distributions. This information is needed to design appropriate normal tissue tolerance studies for different organ systems and/or different boron compounds

Gravitational capture

International Nuclear Information System (INIS)

Bondi, H.

1979-01-01

In spite of the strength of gravitational focres between celestial bodies, gravitational capture is not a simple concept. The principles of conservation of linear momentum and of conservation of angular momentum, always impose severe constraints, while conservation of energy and the vital distinction between dissipative and non-dissipative systems allows one to rule out capture in a wide variety of cases. In complex systems especially those without dissipation, long dwell time is a more significant concept than permanent capture. (author)

Disjunct eddy covariance measurements of volatile organic compound fluxes using proton transfer reaction mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Taipale, R.

2011-07-01

Volatile organic compounds (VOCs) are emitted into the atmosphere from natural and anthropogenic sources, vegetation being the dominant source on a global scale. Some of these reactive compounds are deemed major contributors or inhibitors to aerosol particle formation and growth, thus making VOC measurements essential for current climate change research. This thesis discusses ecosystem scale VOC fluxes measured above a boreal Scots pine dominated forest in southern Finland. The flux measurements were performed using the micrometeorological disjunct eddy covariance (DEC) method combined with proton transfer reaction mass spectrometry (PTR-MS), which is an online technique for measuring VOC concentrations. The measurement, calibration, and calculation procedures developed in this work proved to be well suited to long-term VOC concentration and flux measurements with PTR-MS. A new averaging approach based on running averaged covariance functions improved the determination of the lag time between wind and concentration measurements, which is a common challenge in DEC when measuring fluxes near the detection limit. The ecosystem scale emissions of methanol, acetaldehyde, and acetone were substantial. These three oxygenated VOCs made up about half of the total emissions, with the rest comprised of monoterpenes. Contrary to the traditional assumption that monoterpene emissions from Scots pine originate mainly as evaporation from specialized storage pools, the DEC measurements indicated a significant contribution from de novo biosynthesis to the ecosystem scale monoterpene emissions. This thesis offers practical guidelines for long-term DEC measurements with PTR-MS. In particular, the new averaging approach to the lag time determination seems useful in the automation of DEC flux calculations. Seasonal variation in the monoterpene biosynthesis and the detailed structure of a revised hybrid algorithm, describing both de novo and pool emissions, should be determined in

Gas chromatography-mass spectrometry/mass spectrometry analysis to determine natural and post-administration levels of oestrogens in bovine serum and urine

International Nuclear Information System (INIS)

Biddle, S.; Teale, P.; Robinson, A.; Bowman, J.; Houghton, E.

2007-01-01

A novel analytical approach has been developed and shown to be capable of detecting the isomers of oestradiol in the low ppt (pg mL -1 ) range in bovine serum and urine. Following extractive derivatisation the analytes were detected as their 3-pentafluorobenzoyl 17-trimethylsilyl ether derivatives by gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS), using electron capture negative ion chemical ionisation. The isomers of oestradiol were quantified in both blank and post-administration urine and serum samples, with a view to setting action/threshold levels for these compounds, to allow discrimination between normal samples and samples from animals treated with growth promoting ear implants. A non-parametric statistical assessment of the data resulted in proposed action levels (with a false positive probability of 1 in 1000) of 1.6 and 2.7 ng mL -1 for 17α-oestradiol, in male and female urine, respectively, and 40 and 44 pg mL -1 for 17β-oestradiol, in male and female urine, respectively. An action level of 20 pg mL -1 was proposed for 17α- and 17β-oestradiol in male serum. In female serum the proposed action levels were 40 and 20 pg mL -1 for 17α- and 17β-oestradiol, respectively

Pre-Capture Privacy for Small Vision Sensors.

Science.gov (United States)

Pittaluga, Francesco; Koppal, Sanjeev Jagannatha

2017-11-01

The next wave of micro and nano devices will create a world with trillions of small networked cameras. This will lead to increased concerns about privacy and security. Most privacy preserving algorithms for computer vision are applied after image/video data has been captured. We propose to use privacy preserving optics that filter or block sensitive information directly from the incident light-field before sensor measurements are made, adding a new layer of privacy. In addition to balancing the privacy and utility of the captured data, we address trade-offs unique to miniature vision sensors, such as achieving high-quality field-of-view and resolution within the constraints of mass and volume. Our privacy preserving optics enable applications such as depth sensing, full-body motion tracking, people counting, blob detection and privacy preserving face recognition. While we demonstrate applications on macro-scale devices (smartphones, webcams, etc.) our theory has impact for smaller devices.

Photopolymerizable masses and their hardening using radiation

International Nuclear Information System (INIS)

Bassemir, R.W.; Carlick, D.J.; Dennis, R.; Feig, G.; Nass, G.; Sprenger, G.

1975-01-01

The photo-polymerizable mass consists of a compound of the group of pre-polymers including the dimers and trimers of a polyethylene unsaturated ester of an aliphatic alcohol from the pentaerythrital and polypentaerythrital group. Bound to it is a photo-initiating compound of the acyloin derivates group, of aromatic, aliphatic or alicyclic hydrocarbons with at least one halogen atom on the aromatic nucleus, on the carbon drain or the alicyclic nucleus. Mixtures of substances of the individual groups can be used with those of the other group. The ester is e.g. an acryl, methacryl or itaconic acid ester and the halogen atom e.g. a chlorine, bromine or iodine atom. The photo-polymerizable compound is present in the mass to a weight percent of 15 to 98 and the initiating compound 2 to 85 wt.%. The mass is subjected to ultra-violet as well as to electron or gamma radiation. (DG/LH) [de

Capture ready study

Energy Technology Data Exchange (ETDEWEB)

Minchener, A.

2007-07-15

There are a large number of ways in which the capture of carbon as carbon dioxide (CO{sub 2}) can be integrated into fossil fuel power stations, most being applicable for both gas and coal feedstocks. To add to the choice of technology is the question of whether an existing plant should be retrofitted for capture, or whether it is more attractive to build totally new. This miscellany of choices adds considerably to the commercial risk of investing in a large power station. An intermediate stage between the non-capture and full capture state would be advantageous in helping to determine the best way forward and hence reduce those risks. In recent years the term 'carbon capture ready' or 'capture ready' has been coined to describe such an intermediate stage plant and is now widely used. However a detailed and all-encompassing definition of this term has never been published. All fossil fuel consuming plant produce a carbon dioxide gas byproduct. There is a possibility of scrubbing it with an appropriate CO{sub 2} solvent. Hence it could be said that all fossil fuel plant is in a condition for removal of its CO{sub 2} effluent and therefore already in a 'capture ready' state. Evidently, the practical reality of solvent scrubbing could cost more than the rewards offered by such as the ETS (European Trading Scheme). In which case, it can be said that although the possibility exists of capturing CO{sub 2}, it is not a commercially viable option and therefore the plant could not be described as ready for CO{sub 2} capture. The boundary between a capture ready and a non-capture ready condition using this definition cannot be determined in an objective and therefore universally acceptable way and criteria must be found which are less onerous and less potentially contentious to assess. 16 refs., 2 annexes.

Workshop on neutron capture therapy

Energy Technology Data Exchange (ETDEWEB)

Fairchild, R.G.; Bond, V.P. (eds.)

1986-01-01

Potentially optimal conditions for Neutron Capture Therapy (NCT) may soon be in hand due to the anticipated development of band-pass filtered beams relatively free of fast neutron contaminations, and of broadly applicable biomolecules for boron transport such as porphyrins and monoclonal antibodies. Consequently, a number of groups in the US are now devoting their efforts to exploring NCT for clinical application. The purpose of this Workshop was to bring these groups together to exchange views on significant problems of mutual interest, and to assure a unified and effective approach to the solutions. Several areas of preclinical investigation were deemed to be necessary before it would be possible to initiate clinical studies. As neither the monomer nor the dimer of sulfhydryl boron hydride is unequivocally preferable at this time, studies on both compounds should be continued until one is proven superior.

Workshop on neutron capture therapy

International Nuclear Information System (INIS)

Fairchild, R.G.; Bond, V.P.

1986-01-01

Potentially optimal conditions for Neutron Capture Therapy (NCT) may soon be in hand due to the anticipated development of band-pass filtered beams relatively free of fast neutron contaminations, and of broadly applicable biomolecules for boron transport such as porphyrins and monoclonal antibodies. Consequently, a number of groups in the US are now devoting their efforts to exploring NCT for clinical application. The purpose of this Workshop was to bring these groups together to exchange views on significant problems of mutual interest, and to assure a unified and effective approach to the solutions. Several areas of preclinical investigation were deemed to be necessary before it would be possible to initiate clinical studies. As neither the monomer nor the dimer of sulfhydryl boron hydride is unequivocally preferable at this time, studies on both compounds should be continued until one is proven superior

Analysis of 14C-bearing compounds released by the corrosion of irradiated steel using accelerator mass spectrometry.

Science.gov (United States)

Cvetković, B Z; Salazar, G; Kunz, D; Szidat, S; Wieland, E

2018-06-25

The combination of ion chromatography (IC) with accelerator mass spectrometry (AMS) was developed to determine the speciation of 14C-(radiocarbon) bearing organic compounds in the femto to pico molar concentration range. The development of this compound-specific radiocarbon analysis (CSRA) of carboxylic acids is reported and the application of the method on a leaching solution from neutron-irradiated steel is demonstrated. The background and the dynamic range of the AMS-based method were quantified. On using 14C-labelled standards, the measurements demonstrate the repeatability of the analytical method and the reproducible recovery of the main target carboxylic acids (i.e., acetate, formate, malonate, and oxalate). The detection limit was determined to be in the mid fmol 14C per L level while the dynamic range of the analytical method covers three orders of magnitude from the low fmol to the mid pmol 14C per L level. Cross contamination was found to be negligible during IC fractionation and was accounted for during eluate processing and 14C detection by AMS. The 14C-bearing carboxylates released from an irradiated steel nut into an alkaline leaching solution were analysed using the CSRA-based analytical method with the aim to check the applicability of the approach and develop appropriate sample preparation. The concentrations of 14C-bearing formate and acetate, the main organic corrosion products, were at a low pmol 14C per L level for convenient dimensions of the alkaline leaching experiment which demonstrates that compound-specific 14C AMS is an extremely sensitive analytical method for analysing 14C-bearing compounds. The content of total organic 14C in solution (TO14C) determined by the direct measurement of an aliquot of the leaching solution agrees well with the sum of the 14C concentrations of the individual carboxylates within the uncertainty of the data. Furthermore, the TO14C content is in good agreement with the calculated value using the corrosion rate

Ultrastructural changes in tumor cells following boron neutron capture therapy

International Nuclear Information System (INIS)

Barkla, D.H.; Brown, J.K.; Meriaty, H.; Allen, B.J.

1992-01-01

In a previous study the authors reported on morphological changes in two human melanoma cell lines treated with 10 B-phenylalanine(BPA) and Boron Neutron Capture Therapy(BNCT). The present study describes morphological changes in melanoma and glioma cell lines treated with boron-tetraphenyl porphyrin(BTPP) and BNCT. Porphyrin compounds are selectively taken up by tumor cells and have been used clinically in phototherapy treatment of cancer patients. Boronated porphyrins show good potential as therapeutic agents in BNCT treatment of human cancer patients

Source apportionment of airborne particulate matter using organic compounds as tracers

Science.gov (United States)

Schauer, James J.; Rogge, Wolfgang F.; Hildemann, Lynn M.; Mazurek, Monica A.; Cass, Glen R.; Simoneit, Bernd R. T.

A chemical mass balance receptor model based on organic compounds has been developed that relates source contributions to airborne fine particle mass concentrations. Source contributions to the concentrations of specific organic compounds are revealed as well. The model is applied to four air quality monitoring sites in southern California using atmospheric organic compound concentration data and source test data collected specifically for the purpose of testing this model. The contributions of up to nine primary particle source types can be separately identified in ambient samples based on this method, and approximately 85% of the organic fine aerosol is assigned to primary sources on an annual average basis. The model provides information on source contributions to fine mass concentrations, fine organic aerosol concentrations and individual organic compound concentrations. The largest primary source contributors to fine particle mass concentrations in Los Angeles are found to include diesel engine exhaust, paved road dust, gasoline-powered vehicle exhaust, plus emissions from food cooking and wood smoke, with smaller contribution from tire dust, plant fragments, natural gas combustion aerosol, and cigarette smoke. Once these primary aerosol source contributions are added to the secondary sulfates, nitrates and organics present, virtually all of the annual average fine particle mass at Los Angeles area monitoring sites can be assigned to its source.

Atomic masses of rare-earth isotopes

International Nuclear Information System (INIS)

Schmidt-Ott, W.D.; Kantus, R.; Runte, E.

1981-01-01

A survey is given of decay energies of rare-earth isotopes measured in electron-capture decay by relative Psub(K) ratios, ECsub(K)/β + , and EC/β + ratios. Atomic masses of A = 147 isotopes and of 146 Gd and 148 Dy were derived. The masses of these isotopes and of α-decaying precessors are compared with predictions of current mass formulae. The subshell closure at Z = 64 is shown for N = 82, and 84 isotones. (orig.)

Determination of Volatile Compounds in Four Commercial Samples of Japanese Green Algae Using Solid Phase Microextraction Gas Chromatography Mass Spectrometry

Directory of Open Access Journals (Sweden)

Masayoshi Yamamoto

2014-01-01

Full Text Available Green algae are of great economic importance. Seaweed is consumed fresh or as seasoning in Japan. The commercial value is determined by quality, color, and flavor and is also strongly influenced by the production area. Our research, based on solid phase microextraction gas chromatography mass spectrometry (SPME-GC-MS, has revealed that volatile compounds differ intensely in the four varieties of commercial green algae. Accordingly, 41 major volatile compounds were identified. Heptadecene was the most abundant compound from Okayama (Ulva prolifera, Tokushima (Ulva prolifera, and Ehime prefecture (Ulva linza. Apocarotenoids, such as ionones, and their derivatives were prominent volatiles in algae from Okayama (Ulva prolifera and Tokushima prefecture (Ulva prolifera. Volatile, short chained apocarotenoids are among the most potent flavor components and contribute to the flavor of fresh, processed algae, and algae-based products. Benzaldehyde was predominant in seaweed from Shizuoka prefecture (Monostroma nitidum. Multivariant statistical analysis (PCA enabled simple discrimination of the samples based on their volatile profiles. This work shows the potential of SPME-GC-MS coupled with multivariant analysis to discriminate between samples of different geographical and botanical origins and form the basis for development of authentication methods of green algae products, including seasonings.

Fundamental mass transfer modeling of emission of volatile organic compounds from building materials

Science.gov (United States)

Bodalal, Awad Saad

In this study, a mass transfer theory based model is presented for characterizing the VOC emissions from building materials. A 3-D diffusion model is developed to describe the emissions of volatile organic compounds (VOCs) from individual sources. Then the formulation is extended to include the emissions from composite sources (system comprising an assemblage of individual sources). The key parameters for the model (The diffusion coefficient of the VOC in the source material D, and the equilibrium partition coefficient k e) were determined independently (model parameters are determined without the use of chamber emission data). This procedure eliminated to a large extent the need for emission testing using environmental chambers, which is costly, time consuming, and may be subject to confounding sink effects. An experimental method is developed and implemented to measure directly the internal diffusion (D) and partition coefficients ( ke). The use of the method is illustrated for three types of VOC's: (i) Aliphatic Hydrocarbons, (ii) Aromatic Hydrocarbons and ( iii) Aldehydes, through typical dry building materials (carpet, plywood, particleboard, vinyl floor tile, gypsum board, sub-floor tile and OSB). Then correlations for predicting D and ke based solely on commonly available properties such as molecular weight and vapour pressure were proposed for each product and type of VOC. These correlations can be used to estimate the D and ke when direct measurement data are not available, and thus facilitate the prediction of VOC emissions from the building materials using mass transfer theory. The VOC emissions from a sub-floor material (made of the recycled automobile tires), and a particleboard are measured and predicted. Finally, a mathematical model to predict the diffusion coefficient through complex sources (floor adhesive) as a function of time was developed. Then this model (for diffusion coefficient in complex sources) was used to predict the emission rate from

Gaschromatographic and mass spectroscopic investigations of tall oil rosin acids and diterpenioc compounds and modified diterpene acids

International Nuclear Information System (INIS)

Mayr, M.

1984-12-01

Diterpene resin acids are important constituents of the coniferous wood. The composition of these nonvolatile extractives have been studied by a number of investigations; both naturally occurring resins (oleoresin) and distillation products of the alkaline sulfate pulping process (tall oil) were analyzed. These mixtures find important uses in chemical intermediates, paper sizes, ester gums, coatings and numerous other applications. Owing to the more ameliorate physical properties a major part of tall oil resin acids is chemically modified and is used in intermediate chemicals. Such modifications are the disproportionation in the presence of certain catalysts and the formation of Diels-Alder adducts. The present study was undertaken to obtain detailed information of the overall composition of diterpenoid compounds and to achieve a separation of the complex natural and tall oil mixtures using high resolution glass capillary columns. Furthermore, one objective was to characterize the identified diterpene compounds and Diels-Alder adducts by relative retention values. Additionally the presence of some major adduct components in the modified samples was checked by comparison with pure specimens, independently synthesized or purified by crystallization and the mechanism of the Diels-Alder reaction was investigated. A compilation of the mass spectra of the substances detected in the different samples closes this work. (Author)

Aroma volatile compounds from two fresh pineapple varieties in China.

Science.gov (United States)

Zheng, Liang-Yong; Sun, Guang-Ming; Liu, Yu-Ge; Lv, Ling-Ling; Yang, Wen-Xiu; Zhao, Wei-Feng; Wei, Chang-Bin

2012-01-01

Volatile compounds from two pineapples varieties (Tainong No.4 and No.6) were isolated by headspace solid phase microextraction (HS-SPME) and identified and quantified by gas chromatography-mass spectrometry (GC/MS). In the Tainong No. 4 and No. 6 pineapples, a total of 11 and 28 volatile compounds were identified according to their retention time on capillary columns and their mass spectra, and quantified with total concentrations of 1080.44 μg·kg(-1) and 380.66 μg·kg(-1) in the Tainong No.4 and No. 6 pineapples, respectively. The odor active values (OAVs) of volatile compounds from pineapples were also calculated. According to the OAVs, four compounds were defined as the characteristic aroma compounds for the Tainong No. 4 pineapple, including furaneol, 3-(methylthio)propanoic acid methyl ester, 3-(methylthio)propanoic acid ethyl ester and δ-octalactone. The OAVs of five compounds including ethyl-2-methylbutyrate, methyl-2-methylbutyrate, 3-(methylthio)propanoic acid ethyl ester, ethyl hexanoate and decanal were considered to be the characteristic aroma compounds for the Tainong No. 6 pineapple.

Aroma Volatile Compounds from Two Fresh Pineapple Varieties in China

Directory of Open Access Journals (Sweden)

Chang-Bin Wei

2012-06-01

Full Text Available Volatile compounds from two pineapples varieties (Tainong No.4 and No.6 were isolated by headspace solid phase microextraction (HS-SPME and identified and quantified by gas chromatography-mass spectrometry (GC/MS. In the Tainong No. 4 and No. 6 pineapples, a total of 11 and 28 volatile compounds were identified according to their retention time on capillary columns and their mass spectra, and quantified with total concentrations of 1080.44 µg·kg⁻¹ and 380.66 µg·kg⁻¹ in the Tainong No.4 and No. 6 pineapples, respectively. The odor active values (OAVs of volatile compounds from pineapples were also calculated. According to the OAVs, four compounds were defined as the characteristic aroma compounds for the Tainong No. 4 pineapple, including furaneol, 3-(methylthiopropanoic acid methyl ester, 3-(methylthiopropanoic acid ethyl ester and δ-octalactone. The OAVs of five compounds including ethyl-2-methylbutyrate, methyl-2-methylbutyrate, 3-(methylthiopropanoic acid ethyl ester, ethyl hexanoate and decanal were considered to be the characteristic aroma compounds for the Tainong No. 6 pineapple.

Aroma Volatile Compounds from Two Fresh Pineapple Varieties in China

Science.gov (United States)

Zheng, Liang-Yong; Sun, Guang-Ming; Liu, Yu-Ge; Lv, Ling-Ling; Yang, Wen-Xiu; Zhao, Wei-Feng; Wei, Chang-Bin

2012-01-01

Volatile compounds from two pineapples varieties (Tainong No.4 and No.6) were isolated by headspace solid phase microextraction (HS-SPME) and identified and quantified by gas chromatography-mass spectrometry (GC/MS). In the Tainong No. 4 and No. 6 pineapples, a total of 11 and 28 volatile compounds were identified according to their retention time on capillary columns and their mass spectra, and quantified with total concentrations of 1080.44 μg·kg−1 and 380.66 μg·kg−1 in the Tainong No.4 and No. 6 pineapples, respectively. The odor active values (OAVs) of volatile compounds from pineapples were also calculated. According to the OAVs, four compounds were defined as the characteristic aroma compounds for the Tainong No. 4 pineapple, including furaneol, 3-(methylthio)propanoic acid methyl ester, 3-(methylthio)propanoic acid ethyl ester and δ-octalactone. The OAVs of five compounds including ethyl-2-methylbutyrate, methyl-2-methylbutyrate, 3-(methylthio)propanoic acid ethyl ester, ethyl hexanoate and decanal were considered to be the characteristic aroma compounds for the Tainong No. 6 pineapple. PMID:22837701

Aroma compounds in sweet whey powder.

Science.gov (United States)

Mahajan, S S; Goddik, L; Qian, M C

2004-12-01

Aroma compounds in sweet whey powder were investigated in this study. Volatiles were isolated by solvent extraction followed by solvent-assisted flavor evaporation. Fractionation was used to separate acidic from nonacidic volatiles. Gas chromatography/mass spectrometry and gas chromatography/olfactometry were used for the identification of aroma compounds. Osme methodology was applied to assess the relative importance of each aroma compound. The most aroma-intense free fatty acids detected were acetic, propanoic, butanoic, hexanoic, heptanoic, octanoic, decanoic, dodecanoic, and 9-decenoic acids. The most aroma-intense nonacidic compounds detected were hexanal, heptanal, nonanal, phenylacetaldehyde, 1-octen-3-one, methional, 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, 2,3-dimethylpyrazine, 2,3,5-trimethylpyrazine, furfuryl alcohol, p-cresol, 2-acetylpyrrole, maltol, furaneol, and several lactones. This study suggested that the aroma of whey powder could comprise compounds originating from milk, compounds generated by the starter culture during cheese making, and compounds formed during the manufacturing process of whey powder.

Identification of volatile organic compounds (VOCs) in different colour carrot (Daucus carota L.) cultivars using static headspace/gas chromatography/mass spectrometry

OpenAIRE

Zehra Güler; Fatih Karaca; Halit Yetisir

2015-01-01

Volatile organic compounds (VOCs) as well as sugar and acid contents affect carrot flavour. This study compared VOCs in 11 carrot cultivars. Gas chromatography/mass spectrometry using static headspace technique was applied to analyse the VOCs. The number of VOCs per sample ranged from 17 to 31. The primarily VOCs identified in raw carrots with the exception of “Yellow Stone” were terpenes, ranging from 65 to 95%. The monoterpenes with values ranging from 31 to 89% were higher than those (from...

Chemicalome and metabolome profiling of polymethoxylated flavonoids in Citri Reticulatae Pericarpium based on an integrated strategy combining background subtraction and modified mass defect filter in a Microsoft Excel Platform.

Science.gov (United States)

Zeng, Su-Ling; Duan, Li; Chen, Bai-Zhong; Li, Ping; Liu, E-Hu

2017-07-28

Detection of metabolites in complex biological matrixes is a great challenge because of the background noise and endogenous components. Herein, we proposed an integrated strategy that combined background subtraction program and modified mass defect filter (MMDF) data mining in a Microsoft Excel platform for chemicalome and metabolome profiling of the polymethoxylated flavonoids (PMFs) in Citri Reticulatae Pericarpium (CRP). The exogenously-sourced ions were firstly filtered out by the developed Visual Basic for Applications (VBA) program incorporated in the Microsoft Office. The novel MMDF strategy was proposed for detecting both target and untarget constituents and metabolites based on narrow, well-defined mass defect ranges. The approach was validated to be powerful, and potentially useful for the metabolite identification of both single compound and homologous compound mixture. We successfully identified 30 and 31 metabolites from rat biosamples after oral administration of nobiletin and tangeretin, respectively. A total of 56 PMFs compounds were chemically characterized and 125 metabolites were captured. This work demonstrated the feasibility of the integrated approach for reliable characterization of the constituents and metabolites in herbal medicines. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of conjugate methods with gas chromatography for inorganic compounds analysis

International Nuclear Information System (INIS)

Baccan, N.

1975-01-01

The application of gas chromatography combined with mass spectrometry or with nuclear methods for the analysis of inorganic compounds is studied. The advantages of the use of a gas chromatograph coupled with a quadrupole mass spectrometer or with a high resolution radiation detector, are discussed. We also studied the formation and solvent extraction of metal chelates; an aliquot of the organic phase was directly injected into the gas chromatograph and the eluted compounds were detected by mass spectrometry or, when radioactive, by nuclear methods. (author)

The development of new materials such MOFs for CO2 capture and alkylation of aromatic compounds

International Nuclear Information System (INIS)

Ravon, U.

2010-01-01

This thesis is a European project TOPCOMBI of 22 partners. More specifically, this work is the result of collaboration between ENI (Italy), ITQ (Spain), Repsol (Spain) and IRCELYON (France). This work consists of 2 different themes which improvements can be obtained by finding new materials tailored to the needs. The global energy demands are and will be constantly rising in the coming years. In order to meet this need, new resources must be found and further optimized. Fossil fuels are among the most used resources in the world. Among this 3, natural gas appears to be the most promising point of view of energy efficiency and ecological impact. However, many gas fields cannot be treated because there are too small or too contaminated to be economically viable. One way to make them attractive is to lower the cost of purification using novel separation techniques such as the PSA system. However, there is no currently effective adsorbent to allow a viable economic cleansing. Today, the alkylation reactions represent a very important economic interest. Industrial processes are typically carried out by homogeneous acid reactions or not. Seeing the new environmental restrictions, some homogeneous catalytic processes must be replaced by heterogeneous catalytic reactions with the same yields. To do this, new materials to acid characters were used: the zeolites. However the small size of pores of these compounds prevents selective alkylation reactions of molecules too large compounds such as poly-aromatic. For twenty years, new microporous crystalline compounds have emerged: the MOFs, Metal Organic Frameworks. These compounds have the characteristic to be obtained with different metal cations and organic ligands. These combinations give a wide variety of these compounds at the level of reactivity, pore volume and pore size. In this work, we tried to get different materials with specific characteristics in order to use them in methods for purification of methane in acid

Clinical considerations for neutron capture therapy of brain tumors

International Nuclear Information System (INIS)

Madoc-Jones, H.; Wazer, D.E.; Zamenhof, R.G.; Harling, O.K.; Bernard, J.A. Jr.

1990-01-01

The radiotherapeutic management of primary brain tumors and metastatic melanoma in brain has had disappointing clinical results for many years. Although neutron capture therapy was tried in the US in the 1950s and 1960s, the results were not as hoped. However, with the newly developed capability to measure boron concentrations in blood and tissue both quickly and accurately, and with the advent of epithermal neutron beams obviating the need for scalp and skull reflection, it should not be possible to mount such a clinical trial of NCT again and avoid serious complications. As a prerequisite, it will be important to demonstrate the differential uptake of boron compound in brain tumor as compared with normal brain and its blood supply. If this can be done, then a trial of boron neutron capture therapy for brain tumors should be feasible. Because boronated phenylalanine has been demonstrated to be preferentially taken up by melanoma cells through the biosynthetic pathway for melanin, there is special interest in a trial of boron neutron capture therapy for metastatic melanoma in brain. Again, the use of an epithermal beam would make this a practical possibility. However, because any epithermal (or thermal) beam must contain a certain contaminating level of gamma rays, and because even a pure neutron beam cases gamma rays to be generated when it interacts with tissue, they think that it is essential to deliver treatments with an epithermal beam for boron neutron capture therapy in fractions in order to minimize the late-effects of low-LET gamma rays in the normal tissue

Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS through laboratory studies of inorganic species

Directory of Open Access Journals (Sweden)

W. Hu

2017-08-01

Full Text Available Aerosol mass spectrometers (AMSs and Aerosol Chemical Speciation Monitors (ACSMs commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE to correct for the loss of particles due to bounce. A new capture vapourizer (CV has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH4NO3, NaNO3, (NH42SO4 and NH4Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (Tv ∼ 200–800 °C on the detected fragments, CE and size distributions are investigated. A Tv of 500–550 °C for the CV is recommended. In the CV, CE was identical (around unity for more volatile species (e.g. NH4NO3 and comparable to or higher than the SV for less-volatile species (e.g. (NH42SO4, demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO3 and SO4 species observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO2(g from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH4NO3 and comparable to the SV for NaNO3. . We observe an extremely consistent fragmentation for ammonium compared to very

Radiative electron capture

International Nuclear Information System (INIS)

Biggerstaff, J.A.; Appleton, B.R.; Datz, S.; Moak, C.D.; Neelavathi, V.N.; Noggle, T.S.; Ritchie, R.H.; VerBeek, H.

1975-01-01

Some data are presented for radiative electron capture by fast moving ions. The radiative electron capture spectrum is shown for O 8+ in Ag, along with the energy dependence of the capture cross-section. A discrepancy between earlier data, theoretical prediction, and the present data is pointed out. (3 figs) (U.S.)

Photon attenuation properties of some thorium, uranium and plutonium compounds

Energy Technology Data Exchange (ETDEWEB)

Singh, V. P.; Badiger, N. M. [Karnatak University, Department of Physics, Dharwad-580003, Karnataka (India); Vega C, H. R., E-mail: kudphyvps@rediffmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

2015-10-15

Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

Effect of different drying techniques on the volatile compounds ...

African Journals Online (AJOL)

Purpose: To examine the volatile compounds, thermal stability and morphological characteristics of stevia (Stevia rebaudiana Bertoni) leaves after sun, oven and microwave drying. Methods: Gas chromatography-mass spectrometry with a spectral analysis manager was used to separate the volatile compounds. Dried stevia ...

Assessing microbial degradation of o-xylene at field-scale from the reduction in mass flow rate combined with compound-specific isotope analyses

Science.gov (United States)

Peter, A.; Steinbach, A.; Liedl, R.; Ptak, T.; Michaelis, W.; Teutsch, G.

2004-07-01

In recent years, natural attenuation (NA) has evolved into a possible remediation alternative, especially in the case of BTEX spills. In order to be approved by the regulators, biodegradation needs to be demonstrated which requires efficient site investigation and monitoring tools. Three methods—the Integral Groundwater Investigation method, the compound-specific isotope analysis (CSIA) and a newly developed combination of both—were used in this work to quantify at field scale the biodegradation of o-xylene at a former gasworks site which is heavily contaminated with BTEX and PAHs. First, the Integral Groundwater Investigation method [Schwarz, R., Ptak, T., Holder, T., Teutsch, G., 1998. Groundwater risk assessment at contaminated sites: a new investigation approach. In: Herbert, M. and Kovar, K. (Editors), GQ'98 Groundwater Quality: Remediation and Protection. IAHS Publication 250, pp. 68-71; COH 4 (2000) 170] was applied, which allows the determination of mass flow rates of o-xylene by integral pumping tests. Concentration time series obtained during pumping at two wells were used to calculate inversely contaminant mass flow rates at the two control planes that are defined by the diameter of the maximum isochrone. A reactive transport model was used within a Monte Carlo approach to identify biodegradation as the dominant process for reduction in the contaminant mass flow rate between the two consecutive control planes. Secondly, compound-specific carbon isotope analyses of o-xylene were performed on the basis of point-scale samples from the same two wells. The Rayleigh equation was used to quantify the degree of biodegradation that occurred between the wells. Thirdly, a combination of the Integral Groundwater Investigation method and the compound-specific isotope analysis was developed and applied. It comprises isotope measurements during the integral pumping tests and the evaluation of δ13C time series by an inversion algorithm to obtain spatially

Neutron-Capture Nucleosynthesis and the Chemical Evolution of Globular Clusters

Science.gov (United States)

Shingles, Luke J.

2015-09-01

Elements heavier than iron are almost entirely produced in stars through neutron captures and radioactive decays. Of these heavy elements, roughly half are produced by the slow neutron-capture process (s-process), which takes place under extended exposure to low neutron densities. Most of the s-process production occurs in stars with initial masses between roughly 0.8 and 8 solar masses (Msun), which evolve through the Asymptotic Giant Branch (AGB) phase. This thesis explores several topics related to AGB stars and the s-process, with a focus on comparing theoretical models to observations in the literature on planetary nebulae, post-AGB stars, and globular cluster stars. A recurring theme is the uncertainty of carbon-13-pocket formation, which is crucial for building accurate models of s-process nucleosynthesis. We first investigated whether neutron-capture reactions in AGB stars are the cause of the low sulphur abundances in planetary nebulae and post-AGB stars relative to the interstellar medium. Accounting for uncertainties in the size of the partial mixing zone that forms carbon-13 pockets and the rates of neutron-capture and neutron-producing reactions, our models failed to reproduce the observed levels of sulphur destruction. From this, we concluded that AGB nucleosynthesis is not the cause of the sulphur anomaly. We also discovered a new method to constrain the extent of the partial mixing zone using neon abundances in planetary nebulae. We next aimed to discover the stellar sites of the s-process enrichment in globular clusters that have inter- and intra-cluster variation, with the examples of M4 (relative to M5) and M22, respectively. Using a new chemical evolution code developed by the candidate, we tested models with stellar yields from rotating massive stars and AGB stars. We compared our model predictions for the production of s-process elements with abundances from s-poor and s-rich populations. We found that rotating massive stars alone do not

Mass spectrometric analysis of simple hydrogen compounds; Analyse de composes hydrogenes simples au spectrometre de masse

Energy Technology Data Exchange (ETDEWEB)

Nief, C; Botter, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

A uranium furnace is inserted in the gas inlet line of a mass spectrometer between the leak and the source. The line is fed with simple hydrogen compounds (H{sub 2}O, NH{sub 3}, H{sub 2}S) which are in this way reduced to hydrogen gas. Memory effects are largely avoided by heating the sample line to 90 deg. C. The speed of the isotopic analysis is only slightly less than that of hydrogen gas itself; the accuracy is better due to the reduction of fractionating effects in the leak. For the absolute measurements of deuterium in water, the presence of H{sub 3}{sup +} is a problem. Water samples, prepared by mixing an unknown light water sample with different amounts of heavy water, are equilibrated with hydrogen sulphide and analysis of the two phases of each sample enables the zero of the concentration scale to be determined from the point of intersection of the two curves obtained by plotting mixture composition against the observed isotope ratio in the two phases. The whole experiment can be carried out in the apparatus described which analyses hydrogen in H{sub 2}S and H{sub 2}O in the same way. (author) [French] Un four a uranium est insere dans la ligne d'introduction de gaz d'un spectrometre de masse entre la fuite et la source. La ligne est alimentee par des composes hydrogenes simples (H{sub 2}O, NH{sub 3}, H{sub 2}S) qui sont de cette facon transformes en hydrogene gazeux. On evite dans une large mesure les effets de memoire en chauffant la ligne de l'echantillon jusqu'a 90 deg. C. La vitesse de l'analyse isotopique est seulement legerement inferieure a celle de l'hydrogene gazeux lui-meme; la precision est meilleure du fait de la reduction des effets de fractionnement dans la fuite. Pour les mesures absolues du deuterium dans l'eau, la presence de H{sub 3}{sup +} pose un probleme. Les echantillons d'eau, prepares en melangeant un echantillon inconnu d'eau legere a differentes quantites d'eau lourde, sont equilibres par de l'hydrogene sulfure et l'analyse de

Computational mass spectrometry for small molecules

Science.gov (United States)

2013-01-01

The identification of small molecules from mass spectrometry (MS) data remains a major challenge in the interpretation of MS data. This review covers the computational aspects of identifying small molecules, from the identification of a compound searching a reference spectral library, to the structural elucidation of unknowns. In detail, we describe the basic principles and pitfalls of searching mass spectral reference libraries. Determining the molecular formula of the compound can serve as a basis for subsequent structural elucidation; consequently, we cover different methods for molecular formula identification, focussing on isotope pattern analysis. We then discuss automated methods to deal with mass spectra of compounds that are not present in spectral libraries, and provide an insight into de novo analysis of fragmentation spectra using fragmentation trees. In addition, this review shortly covers the reconstruction of metabolic networks using MS data. Finally, we list available software for different steps of the analysis pipeline. PMID:23453222

Direct Analysis of Organic Compounds in Liquid Using a Miniature Photoionization Ion Trap Mass Spectrometer with Pulsed Carrier-Gas Capillary Inlet.

Science.gov (United States)

Lu, Xinqiong; Yu, Quan; Zhang, Qian; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

2017-08-01

A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity. A limit of detection of 2 ppb could be achieved for 2,4-dimethylaniline in a methanol solution. The sampling system described in the present study is specifically suitable for a miniature photoionization ion trap mass spectrometer that can perform rapid and online analysis for liquid samples. Graphical Abstract ᅟ.

Temperature-programmed desorption for membrane inlet mass spectrometry

DEFF Research Database (Denmark)

Ketola, R.A.; Grøn, C.; Lauritsen, F.R.

1998-01-01

We present a novel technique for analyzing volatile organic compounds in air samples using a solid adsorbent together with temperature-programmed desorption and subsequent detection by membrane inlet mass spectrometry (TPD-MIMS). The new system has the advantage of a fast separation of compounds...... to diffuse through the membrane into the mass spectrometer in a few seconds. In this fashion we could completely separate many similar volatile compounds, for example toluene from xylene and trichloroethene from tetrachloroethene. Typical detection limits were at low or sub-nanogram levels, the dynamic range...

Electron capture detector based on a non-radioactive electron source: operating parameters vs. analytical performance

Directory of Open Access Journals (Sweden)

E. Bunert

2017-12-01

Full Text Available Gas chromatographs with electron capture detectors are widely used for the analysis of electron affine substances such as pesticides or chlorofluorocarbons. With detection limits in the low pptv range, electron capture detectors are the most sensitive detectors available for such compounds. Based on their operating principle, they require free electrons at atmospheric pressure, which are usually generated by a β− decay. However, the use of radioactive materials leads to regulatory restrictions regarding purchase, operation, and disposal. Here, we present a novel electron capture detector based on a non-radioactive electron source that shows similar detection limits compared to radioactive detectors but that is not subject to these limitations and offers further advantages such as adjustable electron densities and energies. In this work we show first experimental results using 1,1,2-trichloroethane and sevoflurane, and investigate the effect of several operating parameters on the analytical performance of this new non-radioactive electron capture detector (ECD.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry

Science.gov (United States)

Furlong, E.T.; Vaught, D.G.; Merten, L.M.; Foreman, W.T.; Gates, Paul M.

1996-01-01

A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.

Purification and Quantification of an Isomeric Compound in a Mixture by Collisional Excitation in Multistage Mass Spectrometry Experiments.

Science.gov (United States)

Jeanne Dit Fouque, Dany; Maroto, Alicia; Memboeuf, Antony

2016-11-15

The differentiation, characterization, and quantification of isomers and/or isobars in mixtures is a recurrent problem in mass spectrometry and more generally in analytical chemistry. Here we present a new strategy to assess the purity of a compound that is susceptible to be contaminated with another isomeric side-product in trace levels. Providing one of the isomers is available as pure sample, this new strategy allows the detection of isomeric contamination. This is done thanks to a "gas-phase collisional purification" inside an ion trap mass spectrometer paving the way for an improved analysis of at least similar samples. This strategy consists in using collision induced dissociation (CID) multistage mass spectrometry (MS 2 and MS 3 ) experiments and the survival yield (SY) technique. It has been successfully applied to mixtures of cyclic poly( L -lactide) (PLA) with increasing amounts of its linear topological isomer. Purification in gas phase of PLA mixtures was established based on SY curves obtained in MS 3 mode: all samples gave rise to the same SY curve corresponding then to the pure cyclic component. This new strategy was sensitive enough to detect traces of linear PLA (<3%) in a sample of cyclic PLA that was supposedly pure according to other characterization techniques ( 1 H NMR, MALDI-HRMS, and size-exclusion chromatography). Moreover, in this case, the presence of linear isomer was undetectable according to MS/MS or MS/MS/MS analysis only as fragment ions are also of the same m/z values. This type of approach could easily be implemented in hyphenated mass spectrometric techniques to improve the structural and quantitative analysis of complex samples.

Organic compounds in radiation fogs in Davis (California)

Science.gov (United States)

Herckes, Pierre; Hannigan, Michael P.; Trenary, Laurie; Lee, Taehyoung; Collett, Jeffrey L.

New stainless steel active fogwater collectors were designed and used in Davis (CA, USA) to collect fogwater for the speciation of organic matter. Organic compounds in fog samples were extracted by liquid-liquid extraction and analyzed by gas chromatography coupled to mass spectrometry. Numerous organic compounds, including various alkanes, polycyclic aromatic hydrocarbons (PAH) and alkanoic acids, have been identified in the fogwater samples. Higher molecular weight (MW) compounds are preferentially associated with an insoluble phase inside the fog drops, whereas lower molecular weight and more polar compounds are found predominantly in the dissolved phase. Concentrations in the dissolved phase were sometimes much higher than estimated by the compounds' aqueous solubilities.

Determination of Wastewater Compounds in Sediment and Soil by Pressurized Solvent Extraction, Solid-Phase Extraction, and Capillary-Column Gas Chromatography/Mass Spectrometry

Science.gov (United States)

Burkhardt, Mark R.; Zaugg, Steven D.; Smith, Steven G.; ReVello, Rhiannon C.

2006-01-01

A method for the determination of 61 compounds in environmental sediment and soil samples is described. The method was developed in response to increasing concern over the effects of endocrine-disrupting chemicals in wastewater and wastewater-impacted sediment on aquatic organisms. This method also may be used to evaluate the effects of combined sanitary and storm-sewer overflow on the water and sediment quality of urban streams. Method development focused on the determination of compounds that were chosen on the basis of their endocrine-disrupting potential or toxicity. These compounds include the alkylphenol ethoxylate nonionic surfactants and their degradates, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Sediment and soil samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from interfering matrix components by high-pressure water/isopropyl alcohol extraction. The compounds were isolated using disposable solid-phase extraction (SPE) cartridges containing chemically modified polystyrene-divinylbenzene resin. The cartridges were dried with nitrogen gas, and then sorbed compounds were eluted with methylene chloride (80 percent)-diethyl ether (20 percent) through Florisil/sodium sulfate SPE cartridge, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-sand samples fortified at 4 to 72 micrograms averaged 76 percent ?13 percent relative standard deviation for all method compounds. Initial method reporting levels for single-component compounds ranged from 50 to 500 micrograms per kilogram. The concentrations of 20 out of 61 compounds initially will be reported as estimated with the 'E' remark code for one of three reasons: (1) unacceptably low-biased recovery (less than 60 percent) or highly variable method performance

Effects of capturing and collaring on polar bears: findings from long-term research on the southern Beaufort Sea population

Science.gov (United States)

Rode, Karyn D.; Pagano, Anthony M.; Bromaghin, Jeffrey F.; Atwood, Todd C.; Durner, George M.; Simac, Kristin S.; Amstrup, Steven C.

2014-01-01

Context: The potential for research methods to affect wildlife is an increasing concern among both scientists and the public. This topic has a particular urgency for polar bears because additional research is needed to monitor and understand population responses to rapid loss of sea ice habitat.Aims: This study used data collected from polar bears sampled in the Alaska portion of the southern Beaufort Sea to investigate the potential for capture to adversely affect behaviour and vital rates. We evaluated the extent to which capture, collaring and handling may influence activity and movement days to weeks post-capture, and body mass, body condition, reproduction and survival over 6 months or more.Methods: We compared post-capture activity and movement rates, and relationships between prior capture history and body mass, body condition and reproductive success. We also summarised data on capture-related mortality.Key results: Individual-based estimates of activity and movement rates reached near-normal levels within 2–3 days and fully normal levels within 5 days post-capture. Models of activity and movement rates among all bears had poor fit, but suggested potential for prolonged, lower-level rate reductions. Repeated captures was not related to negative effects on body condition, reproduction or cub growth or survival. Capture-related mortality was substantially reduced after 1986, when immobilisation drugs were changed, with only 3 mortalities in 2517 captures from 1987–2013.Conclusions: Polar bears in the southern Beaufort Sea exhibited the greatest reductions in activity and movement rates 3.5 days post-capture. These shorter-term, post-capture effects do not appear to have translated into any long-term effects on body condition, reproduction, or cub survival. Additionally, collaring had no effect on polar bear recovery rates, body condition, reproduction or cub survival.Implications: This study provides empirical evidence that current capture

Characterisation of organic compounds in aerosol particles from a finnish forest by on-line coupled supercritical fluid extraction-liquid chromatography-gas chromatography-mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Shimmo, Masahiko; Jaentti, Jaana; Hartonen, Kari; Hyoetylaeinen, Tuulia; Riekkola, Marja-Liisa [Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, 00014, Helsinki (Finland); Aalto, Pasi; Kulmala, Markku [Division of Atmospheric Sciences, Department of Physical Sciences, University of Helsinki, P.O. Box 64, 00014, Helsinki (Finland)

2004-04-01

During the European Union project Quantification of Aerosol Nucleation in the European Boundary Layer (QUEST), which began in spring 2003, atmospheric aerosol particles were collected in a Finnish Scots pine forest using a high-volume sampler. The organic compounds in the filter samples were then analysed by on-line coupled supercritical fluid extraction-liquid chromatography-gas chromatography-mass spectrometry (SFE-LC-GC-MS). The sample was first extracted by SFE. During LC the extracts were fractionated into three fractions according to polarity. The final separation was carried out by GC-MS. A fraction volume as high as 840 {mu}L was transferred to the GC, using the partial concurrent eluent evaporation technique. The same instrumentation, with an in-situ SFE derivatisation method, was used to analyse organic acids. Major compounds such as n-alkanes and PAH were analysed quantitatively. Their concentrations were lower than those usually observed in urban areas or in other forest areas in Europe. The wind direction was one of the most important factors affecting changes in the daily concentrations of these compounds. Scots pine needles were analysed with the same system to obtain reference data for identification of biogenic compounds in aerosol particles. Other organic compounds found in this study included hopanes, steranes, n-alkanals, n-alkan-2-ones, oxy-PAH, and alkyl-PAH; some biogenic products, including oxidation products of monoterpenes, were also identified. (orig.)

Identification of non-volatile compounds and their migration from hot melt adhesives used in food packaging materials characterized by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry.

Science.gov (United States)

Vera, Paula; Canellas, Elena; Nerín, Cristina

2013-05-01

The identification of unknown non-volatile migrant compounds from adhesives used in food contact materials is a very challenging task because of the number of possible compounds involved, given that adhesives are complex mixtures of chemicals. The use of ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-MS/QTOF) is shown to be a successful tool for identifying non-targeted migrant compounds from two hot melt adhesives used in food packaging laminates. Out of the seven migrants identified and quantified, five were amides and one was a compound classified in Class II of the Cramer toxicity. None of the migration values exceeded the recommended Cramer exposure values.

Capturing Thoughts, Capturing Minds?

DEFF Research Database (Denmark)

Nielsen, Janni

2004-01-01

Think Aloud is cost effective, promises access to the user's mind and is the applied usability technique. But 'keep talking' is difficult, besides, the multimodal interface is visual not verbal. Eye-tracking seems to get around the verbalisation problem. It captures the visual focus of attention...

High-Throughput Screening and Quantitation of Target Compounds in Biofluids by Coated Blade Spray-Mass Spectrometry.

Science.gov (United States)

Tascon, Marcos; Gómez-Ríos, Germán Augusto; Reyes-Garcés, Nathaly; Poole, Justen; Boyacı, Ezel; Pawliszyn, Janusz

2017-08-15

Most contemporary methods of screening and quantitating controlled substances and therapeutic drugs in biofluids typically require laborious, time-consuming, and expensive analytical workflows. In recent years, our group has worked toward developing microextraction (μe)-mass spectrometry (MS) technologies that merge all of the tedious steps of the classical methods into a simple, efficient, and low-cost methodology. Unquestionably, the automation of these technologies allows for faster sample throughput, greater reproducibility, and radically reduced analysis times. Coated blade spray (CBS) is a μe technology engineered for extracting/enriching analytes of interest in complex matrices, and it can be directly coupled with MS instruments to achieve efficient screening and quantitative analysis. In this study, we introduced CBS as a technology that can be arranged to perform either rapid diagnostics (single vial) or the high-throughput (96-well plate) analysis of biofluids. Furthermore, we demonstrate that performing 96-CBS extractions at the same time allows the total analysis time to be reduced to less than 55 s per sample. Aiming to validate the versatility of CBS, substances comprising a broad range of molecular weights, moieties, protein binding, and polarities were selected. Thus, the high-throughput (HT)-CBS technology was used for the concomitant quantitation of 18 compounds (mixture of anabolics, β-2 agonists, diuretics, stimulants, narcotics, and β-blockers) spiked in human urine and plasma samples. Excellent precision (∼2.5%), accuracy (≥90%), and linearity (R 2 ≥ 0.99) were attained for all the studied compounds, and the limits of quantitation (LOQs) were within the range of 0.1 to 10 ng·mL -1 for plasma and 0.25 to 10 ng·mL -1 for urine. The results reported in this paper confirm CBS's great potential for achieving subsixty-second analyses of target compounds in a broad range of fields such as those related to clinical diagnosis, food, the

Post-capture vibration suppression of spacecraft via a bio-inspired isolation system

Science.gov (United States)

Dai, Honghua; Jing, Xingjian; Wang, Yu; Yue, Xiaokui; Yuan, Jianping

2018-05-01

Inspired by the smooth motions of a running kangaroo, a bio-inspired quadrilateral shape (BIQS) structure is proposed to suppress the vibrations of a free-floating spacecraft subject to periodic or impulsive forces, which may be encountered during on-orbit servicing missions. In particular, the BIQS structure is installed between the satellite platform and the capture mechanism. The dynamical model of the BIQS isolation system, i.e. a BIQS structure connecting the platform and the capture mechanism at each side, is established by Lagrange's equations to simulate the post-capture dynamical responses. The BIQS system suffering an impulsive force is dealt with by means of a modified version of Lagrange's equations. Furthermore, the classical harmonic balance method is used to solve the nonlinear dynamical system subject to periodic forces, while for the case under impulsive forces the numerical integration method is adopted. Due to the weightless environment in space, the present BIQS system is essentially an under-constrained dynamical system with one of its natural frequencies being identical to zero. The effects of system parameters, such as the number of layers in BIQS, stiffness, assembly angle, rod length, damping coefficient, masses of satellite platform and capture mechanism, on the isolation performance of the present system are thoroughly investigated. In addition, comparisons between the isolation performances of the presently proposed BIQS isolator and the conventional spring-mass-damper (SMD) isolator are conducted to demonstrate the advantages of the present isolator. Numerical simulations show that the BIQS system has a much better performance than the SMD system under either periodic or impulsive forces. Overall, the present BIQS isolator offers a highly efficient passive way for vibration suppressions of free-floating spacecraft.

Chromatographic methods of the measurements of the chloride compounds in troposphere and stratosphere

International Nuclear Information System (INIS)

Lasa, J.; Rosiek, J.

1992-01-01

The paper contains a description of various chromatographic techniques used for the analysis of the tropospheric techniques used for the analysis of the tropospheric and stratospheric halogenated compounds. The types of the column packings used for separation of halogenated compounds are described. Model chromatograms illustrating the separation of halogenated compounds are presented. The methods of the air sampling and injection for the packed and capillary columns were described. The methods of the preparation of gas calibration mixtures are presented. Operational conditions for electron capture detector used by the authors of quoted paper are also given. (author). 66 refs, 29 figs, 13 tabs

Electron capture by highly charged low-velocity ions

International Nuclear Information System (INIS)

Cocke, C.L.; Dubois, R.; Justiniano, E.; Gray, T.J.; Can, C.

1982-01-01

This paper describes the use of a fast heavy ion beam to produce, by bombardment of gaseous targets, highly-charged low-velocity recoil ions, and the use of these secondary ions in turn as projectiles in studies of electron capture and ionization in low-energy collision systems. The interest in collisions involving low-energy highly-charged projectiles comes both from the somewhat simplifying aspects of the physics which attend the long-range capture and from applications to fusion plasmas, astrophysics and more speculative technology such as the production of X-ray lasers. The ions of interest in such applications should have both electronic excitation and center-of-mass energies in the keV range and cannot be produced by simply stripping fast heavy ion beams. Several novel types of ion source have been developed to produce low-energy highly-charged ions, of which the secondary ion recoil source discussed in this paper is one. (Auth.)

Biochar and enhanced phosphate capture: Mapping mechanisms to functional properties.

Science.gov (United States)

Shepherd, Jessica G; Joseph, Stephen; Sohi, Saran P; Heal, Kate V

2017-07-01

A multi-technique analysis was performed on a range of biochar materials derived from secondary organic resources and aimed at sustainable recovery and re-use of wastewater phosphorus (P). Our purpose was to identify mechanisms of P capture in biochar and thereby inform its future optimisation as a sustainable P fertiliser. The biochar feedstock comprised pellets of anaerobically digested sewage sludge (PAD) or pellets of the same blended in the ratio 9:1 with ochre sourced from minewater treatment (POCAD), components which have limited alternative economic value. In the present study the feedstocks were pyrolysed at two highest treatment temperatures of 450 and 550 °C. Each of the resulting biochars were repeatedly exposed to a 20 mg l -1 PO 4 -P solution, to produce a parallel set of P-exposed biochars. Biochar exterior and/or interior surfaces were quantitatively characterised using laser-ablation (LA)-ICP-MS, X-ray diffraction, X-ray photo-electron spectroscopy (XPS) and scanning electron microscopy coupled with energy dispersive X-ray. The results highlighted the general importance of Fe minerals in P capture. XPS analysis of POCAD550 indicated lower oxidation state Fe2p3 bonding compared to POCAD450, and LA-ICP-MS indicated stronger covariation of Fe and S, even after P exposure. This suggests that low-solubility Fe/S compounds are formed during pyrolysis, are affected by process parameters and impact on P capture. Other data suggested capture roles for aluminium, calcium and silicon. Overall, our analyses suggest that a range of mechanisms for P capture are concurrently active in biochar. We highlighted the potential to manipulate these through choice of form and composition of feedstock as well as pyrolysis processing, so that biochar may be increasingly tailored towards specific functionality. Copyright © 2017 Elsevier Ltd. All rights reserved.

Climate Change Mitigation Technologies: the Siemens Roadmap to Carbon Capture and Storage

Energy Technology Data Exchange (ETDEWEB)

Voges, K.

2007-07-01

A full range of technology options will have to be deployed until 2025 to get the global CO{sub 2} emissions on a 550 ppm stabilization track. The focus of the paper will be on Carbon Capture and Storage (CCS) as an indispensable part of a carbon constrained energy infrastructure. In CCS our main long term focus is clearly on coal based processes. For Greenfield applications Siemens is prioritizing IGCC based pre-combustion capture. Post-combustion capture is pursued for steam power plant retrofit. (a) IGCC with pre-combustion capture: A first F-class based demonstration plant could be available until 2014. The roadmap addresses gasifier scale up, hydrogen burner and turbine development and integration issues. Beyond that a bundle of further efficiency improvement measures will further enhance efficiency and economic competitiveness. (b) Post-combustion capture: The development aims at optimizing existing solvents or developing new ones and integrating the complete unit with its mass and heat interchange system into the power plant. (c) CO{sub 2} Compressors: For efficiency and operating flexibility reasons Siemens Power Generation prefers gear-type compressors instead of single shaft compressors. The improvement of maintainability and the reduced number of stages or corrosion protection are issues addressed in current R and D activities. (auth)

Determination of Volatile Compounds of Illicium verum Hook. f ...

African Journals Online (AJOL)

02.1 mass spectral library in MSD ChemStation. Relative content of each compound in essential oil was calculated by peak area normalization method. These compounds accounted for more than 90 % in total star anise aroma molecules, including trans-anethole (75.76 %), p- anisaldehyde (8.65 %), estragole (4.70 %),.

Factorization for the light-jet mass and hemisphere soft function

Energy Technology Data Exchange (ETDEWEB)

Becher, Thomas [Albert Einstein Center for Fundamental Physics,Institut für Theoretische Physik, Universität Bern,Sidlerstrasse 5, CH-3012 Bern (Switzerland); Pecjak, Benjamin D. [Institute for Particle Physics Phenomenology, University of Durham,DH1 3LE Durham (United Kingdom); Shao, Ding Yu [Albert Einstein Center for Fundamental Physics,Institut für Theoretische Physik, Universität Bern,Sidlerstrasse 5, CH-3012 Bern (Switzerland)

2016-12-05

Many collider observables suffer from non-global logarithms not captured by standard resummation techniques. Classic examples are the light-jet mass event shape in the limit of small mass and the related hemisphere soft function. We derive factorization formulas for both of these and explicitly demonstrate that they capture all logarithms present at NNLO. These formulas achieve full scale separation and provide the basis for all-order resummations. A characteristic feature of non-global observables is that the soft radiation is driven by multi-Wilson-line operators, and the ones arising here map onto those relevant for the case of narrow-cone jet cross sections. Numerically, the contributions of non-global logarithms to resummed hemisphere-mass event shapes are sizeable.

Resonance enhancement of neutrinoless double electron capture

International Nuclear Information System (INIS)

Krivoruchenko, M.I.; Simkovic, Fedor; Frekers, Dieter; Faessler, Amand

2011-01-01

The process of neutrinoless double electron (0νECEC) capture is revisited for those cases where the two participating atoms are nearly degenerate in mass. The theoretical framework is the formalism of an oscillation of two atoms with different total lepton number (and parity), one of which can be in an excited state so that mass degeneracy is realized. In such a case and assuming light Majorana neutrinos, the two atoms will be in a mixed configuration with respect to the weak interaction. A resonant enhancement of transitions between such pairs of atoms will occur, which could be detected by the subsequent electromagnetic de-excitation of the excited state of the daughter atom and nucleus. Available data of atomic masses, as well as nuclear and atomic excitations are used to select the most likely candidates for the resonant transitions. Assuming an effective mass for the Majorana neutrino of 1 eV, some half-lives are predicted to be as low as 10 22 years in the unitary limit. It is argued that, in order to obtain more accurate predictions for the 0νECEC half-lives, precision mass measurements of the atoms involved are necessary, which can readily be accomplished by today's high precision Penning traps. Further advancements also require a better understanding of high-lying excited states of the final nuclei (i.e. excitation energy, angular momentum and parity) and the calculation of the nuclear matrix elements.

Magneto-elastic biosensors: Influence of different thiols on pathogen capture efficiency

International Nuclear Information System (INIS)

Dalla Pozza, Márcia; Possan, André L.; Roesch-Ely, Mariana; Missell, Frank P.

2017-01-01

Magneto-elastic biosensors have mass sensitivity to biological species, offering reliability and reproducibility in the detection of pathogens such as Escherichia coli. In this work, amorphous ribbons of Metglas 2826MB3 were coated with layers of Cr and Au by DC magnetron sputtering and cut to 5 mm × 1 mm. The influence of different thiols on captured pathogens was studied. The compounds cystamine (CYS), cysteamine (CYSTE) and mercaptopropionic acid (MPA) were deposited on Au-covered surfaces, followed by antibodies. The roughness parameters Ra and Rq were determined using atomic force microscopy (AFM) and micrographs from scanning electron microscopy with a field emission gun (FESEM) were also utilized. Biosensors formed with MPA showed an increased efficiency for attracting E. coli compared to biosensors with CYS and CYSTE, but large standard deviations were observed, making reproducibility and reliability difficult for that biosensor. Sensors tested with CYSTE showed greater efficiency and a lower detection limit than sensors with CYS. The results indicated that the size of the carbon chain and the terminal grouping influence the effectiveness of immobilization on magneto-elastic biosensors. - Highlights: • Atomic force microscopy (AFM) and scanning electron microscopy with field emission gun (FESEM) were utilized. • Biosensor with cysteamine (CYSTE) gave lower detection limit for E.coli than mercaptopropionic acid (MPA) or cystamine (CYS)

Magneto-elastic biosensors: Influence of different thiols on pathogen capture efficiency

Energy Technology Data Exchange (ETDEWEB)

Dalla Pozza, Márcia; Possan, André L. [Centro de Ciências Exatas e Tecnologia, Universidade de Caxias do Sul, Caxias do Sul, RS (Brazil); Roesch-Ely, Mariana [Instituto de Biotecnologia, Universidade de Caxias do Sul, Caxias do Sul, RS (Brazil); Missell, Frank P., E-mail: fpmissel@ucs.br [Centro de Ciências Exatas e Tecnologia, Universidade de Caxias do Sul, Caxias do Sul, RS (Brazil)

2017-06-01

Magneto-elastic biosensors have mass sensitivity to biological species, offering reliability and reproducibility in the detection of pathogens such as Escherichia coli. In this work, amorphous ribbons of Metglas 2826MB3 were coated with layers of Cr and Au by DC magnetron sputtering and cut to 5 mm × 1 mm. The influence of different thiols on captured pathogens was studied. The compounds cystamine (CYS), cysteamine (CYSTE) and mercaptopropionic acid (MPA) were deposited on Au-covered surfaces, followed by antibodies. The roughness parameters Ra and Rq were determined using atomic force microscopy (AFM) and micrographs from scanning electron microscopy with a field emission gun (FESEM) were also utilized. Biosensors formed with MPA showed an increased efficiency for attracting E. coli compared to biosensors with CYS and CYSTE, but large standard deviations were observed, making reproducibility and reliability difficult for that biosensor. Sensors tested with CYSTE showed greater efficiency and a lower detection limit than sensors with CYS. The results indicated that the size of the carbon chain and the terminal grouping influence the effectiveness of immobilization on magneto-elastic biosensors. - Highlights: • Atomic force microscopy (AFM) and scanning electron microscopy with field emission gun (FESEM) were utilized. • Biosensor with cysteamine (CYSTE) gave lower detection limit for E.coli than mercaptopropionic acid (MPA) or cystamine (CYS)

Integrated modelling of two xenobiotic organic compounds

DEFF Research Database (Denmark)

Lindblom, Erik Ulfson; Gernaey, K.V.; Henze, Mogens

2006-01-01

This paper presents a dynamic mathematical model that describes the fate and transport of two selected xenobiotic organic compounds (XOCs) in a simplified representation. of an integrated urban wastewater system. A simulation study, where the xenobiotics bisphenol A and pyrene are used as reference...... compounds, is carried out. Sorption and specific biological degradation processes are integrated with standardised water process models to model the fate of both compounds. Simulated mass flows of the two compounds during one dry weather day and one wet weather day are compared for realistic influent flow...... rate and concentration profiles. The wet weather day induces resuspension of stored sediments, which increases the pollutant load on the downstream system. The potential of the model to elucidate important phenomena related to origin and fate of the model compounds is demonstrated....

Determination of DDTs and PCBs by capillary gas chromatography and electron capture detection

International Nuclear Information System (INIS)

1988-01-01

This reference method deals with the determination of DDTs and PCBs in marine environmental samples using high resolution gas chromatography. Several other halogenated pesticides and other electron capturing organic compounds may be present in samples and many of these may also be determined by this method. Not all electron capturing residues will be resistant to all of the clean up procedures described here for the analysis of DTTs and PCBs. Therefore, additional information on the stability of some common pesticides using this methodology is also provided. The high separation power of open tubular (''capillary'') columns allows the identification and quantification of many compounds in the complex mixtures occurring in environmental samples. This manual provides information on the theoretical and practical aspects of the use of these high resolution columns for the analysis of DDTs and PCBs in environmental samples. The qualitative and quantitative method can be applied to any sample type (aerosol/vapour, water, particulates, biota, etc.) provided that suitable cleaned-up extracts dissolved in n-hexane are available for injection into the GC system. For example, methods for obtaining these cleaned-up sample extracts from marine organisms are described in detail in UNEP Reference Method no. 14 and for sediments in No. 17. The change in the field of application by analysing by capillary rather than packed columns may be less dramatic for DDTs. However, with the increased separation, the possibilities of inaccurate analysis resulting from overlap with interfering compounds is reduced. 7 refs, 1 fig., 3 tabs

Gas chromatography-mass spectrometry/mass spectrometry analysis to determine natural and post-administration levels of oestrogens in bovine serum and urine

Energy Technology Data Exchange (ETDEWEB)

Biddle, S. [HFL, Newmarket Road, Fordham, Cambridgeshire (United Kingdom)]. E-mail: sbiddle@hfl.co.uk; Teale, P. [HFL, Newmarket Road, Fordham, Cambridgeshire (United Kingdom); Robinson, A. [HFL, Newmarket Road, Fordham, Cambridgeshire (United Kingdom); Bowman, J. [HFL, Newmarket Road, Fordham, Cambridgeshire (United Kingdom); Houghton, E. [HFL, Newmarket Road, Fordham, Cambridgeshire (United Kingdom)

2007-03-14

A novel analytical approach has been developed and shown to be capable of detecting the isomers of oestradiol in the low ppt (pg mL{sup -1}) range in bovine serum and urine. Following extractive derivatisation the analytes were detected as their 3-pentafluorobenzoyl 17-trimethylsilyl ether derivatives by gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS), using electron capture negative ion chemical ionisation. The isomers of oestradiol were quantified in both blank and post-administration urine and serum samples, with a view to setting action/threshold levels for these compounds, to allow discrimination between normal samples and samples from animals treated with growth promoting ear implants. A non-parametric statistical assessment of the data resulted in proposed action levels (with a false positive probability of 1 in 1000) of 1.6 and 2.7 ng mL{sup -1} for 17{alpha}-oestradiol, in male and female urine, respectively, and 40 and 44 pg mL{sup -1} for 17{beta}-oestradiol, in male and female urine, respectively. An action level of 20 pg mL{sup -1} was proposed for 17{alpha}- and 17{beta}-oestradiol in male serum. In female serum the proposed action levels were 40 and 20 pg mL{sup -1} for 17{alpha}- and 17{beta}-oestradiol, respectively.

Capturing near-Earth asteroids around Earth

Science.gov (United States)

Hasnain, Zaki; Lamb, Christopher A.; Ross, Shane D.

2012-12-01

The list of detected near-Earth asteroids (NEAs) is constantly growing. NEAs are likely targets for resources to support space industrialization, as they may be the least expensive source of certain needed raw materials. The limited supply of precious metals and semiconducting elements on Earth may be supplemented or even replaced by the reserves floating in the form of asteroids around the solar system. Precious metals make up a significant fraction NEAs by mass, and even one metallic asteroid of ˜1km size and fair enrichment in platinum-group metals would contain twice the tonnage of such metals already harvested on Earth. There are ˜1000 NEAs with a diameter of greater than 1 km. Capturing these asteroids around the Earth would expand the mining industry into an entirely new dimension. Having such resources within easy reach in Earth's orbit could provide an off-world environmentally friendly remedy for impending terrestrial shortages, especially given the need for raw materials in developing nations. In this paper, we develop and implement a conceptually simple algorithm to determine trajectory characteristics necessary to move NEAs into capture orbits around the Earth. Altered trajectories of asteroids are calculated using an ephemeris model. Only asteroids of eccentricity less than 0.1 have been studied and the model is restricted to the ecliptic plane for simplicity. We constrain the time of retrieval to be 10 years or less, based on considerations of the time to return on investment. For the heliocentric phase, constant acceleration is assumed. The acceleration required for transporting these asteroids from their undisturbed orbits to the sphere of influence of the Earth is the primary output, along with the impulse or acceleration necessary to effect capture to a bound orbit once the Earth's sphere of influence is reached. The initial guess for the constant acceleration is provided by a new estimation method, similar in spirit to Edelbaum's. Based on the

Muon capture in metallic, chemical and solution systems - recent results and future plans at Los Alamos

International Nuclear Information System (INIS)

Naumann, R.A.; Schmidt, G.; Knight, J.D.; Mausner, L.F.; Orth, C.J.; Schillaci, M.E.

1977-01-01

The recent results on capture ratios and the KX-ray intensity patterns in negative muon capture experiments carried out at Los Alamos are outlined. A set of experiments was devoted to capture process in alkali halide compounds. The capture ratio for alkali chlorides and for potassium halides was found to reveal the fall-out with increasing atomic number. The measurements carried out on aqueous ions of NaCl verifies the indication that the muonic KX-ray intensity patterns show enhanced intensity of the higher K numbers in comparison to that in crystalline NaCl. The systematic investigations of the variations of the K mesic X-ray intensity pattern was carried out for pure elements with atomic number ranging from 6 to 34. The dependence of the X-ray intensity pattern on atomic number exhibits a maximum in the vicinity of Z=25 (manganese). Another research program is concerned with quantitative tests of the dependence of the muon capture on composition for solid solutions. Measurements are underway using two binary metallic alloy systems of aluminium-copper, silver-zinc and three continuous solid solutions formed by sodium chloride-sodium bromide, potassium chloride-potassium bromide and potassium bromide-potassium iodide

Simultaneous determination of phenolic compounds in Equisetum palustre L. by ultra high performance liquid chromatography with tandem mass spectrometry combined with matrix solid-phase dispersion extraction.

Science.gov (United States)

Wei, Zuofu; Pan, Youzhi; Li, Lu; Huang, Yuyang; Qi, Xiaolin; Luo, Meng; Zu, Yuangang; Fu, Yujie

2014-11-01

A method based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with tandem mass spectrometry is presented for the extraction and determination of phenolic compounds in Equisetum palustre. This method combines the high efficiency of matrix solid-phase dispersion extraction and the rapidity, sensitivity, and accuracy of ultra high performance liquid chromatography with tandem mass spectrometry. The influential parameters of the matrix solid-phase dispersion extraction were investigated and optimized. The optimized conditions were as follows: silica gel was selected as dispersing sorbent, the ratio of silica gel to sample was selected to be 2:1 (400/200 mg), and 8 mL of 80% methanol was used as elution solvent. Furthermore, a fast and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the determination of nine phenolic compounds in E. palustre. This method was carried out within <6 min, and exhibited satisfactory linearity, precision, and recovery. Compared with ultrasound-assisted extraction, the proposed matrix solid-phase dispersion procedure possessed higher extraction efficiency, and was more convenient and time saving with reduced requirements on sample and solvent amounts. All these results suggest that the developed method represents an excellent alternative for the extraction and determination of active components in plant matrices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of a wide range of volatile organic compounds in ambient air using multisorbent adsorption/thermal desorption and gas chromatography/mass spectrometry

Science.gov (United States)

Pankow, J.F.; Luo, W.; Isabelle, L.M.; Bender, D.A.; Baker, R.J.

1998-01-01

Adsorption/thermal desorption with multisorbent air-sampling cartridges was developed for the determination of 87 method analytes including halogenated alkanes, halogenated alkenes, ethers, alcohols, nitriles, esters, ketones, aromatics, a disulfide, and a furan. The volatilities of the compounds ranged from that of dichlorofluoromethane (CFC12) to that of 1,2,3- trichlorobenzene. The eight most volatile compounds were determined using a 1.5-L air sample and a sample cartridge containing 50 mg of Carbotrap B and 280 mg of Carboxen 1000; the remaining 79 compounds were determined using a 5-L air sample and a cartridge containing 180 mg of Carbotrap B and 70 mg of Carboxen 1000. Analysis and detection were by gas chromatography/mass spectrometry. The minimum detectable level (MDL) concentration values ranged from 0.01 parts per billion by volume (ppbv) for chlorobenzene to 0.4 ppbv for bromomethane; most of the MDL values were in the range 0.02-0.06 ppbv. No breakthrough was detected with the prescribed sample volumes. Analyte stability on the cartridges was very good. Excellent recoveries were obtained with independent check standards. Travel spike recoveries ranged from 90 to 110% for 72 of the 87 compounds. The recoveries were less than 70% for bromomethane and chloroethene and for a few compounds such as methyl acetate that are subject to losses by hydrolysis; the lowest travel spike recovery was obtained for bromomethane (62%). Blank values for all compounds were either below detection or very low. Ambient atmospheric sampling was conducted in New Jersey from April to December, 1997. Three sites characterized by low, moderate, and high densities of urbanization/traffic were sampled. The median detected concentrations of the compounds were either similar at all three sites (as with the chlorofluorocarbon compounds) or increased with the density of urbanization/traffic (as with dichloromethane, MTBE, benzene, and toluene). For toluene, the median detected

Control of radioactive wastes and coupling of neutron/gamma measurements: use of radiative capture for the correction of matrix effects that penalize the fissile mass measurement by active neutron interrogation; Controle des dechets radioactifs et couplage de mesures neutron/gamma: exploitation de la capture radiative pour corriger les effets de matrice penalisant la mesure de la masse fissile par interrogation neutronique active

Energy Technology Data Exchange (ETDEWEB)

Loche, F

2006-10-15

In the framework of radioactive waste drums control, difficulties arise in the nondestructive measurement of fissile mass ({sup 235}U, {sup 239}Pu..) by Active Neutron Interrogation (ANI), when dealing with matrices containing materials (Cl, H...) influencing the neutron flux. The idea is to use the neutron capture reaction (n,{gamma}) to determine the matrix composition to adjust the ANI calibration coefficient value. This study, dealing with 118 litres, homogeneous drums of density less than 0,4 and composed of chlorinated and/or hydrogenated materials, leads to build abacus linking the {gamma} ray peak areas to the ANI calibration coefficient. Validation assays of these abacus show a very good agreement between the corrected and true fissile masses for hydrogenated matrices (max. relative standard deviation: 23 %) and quite good for chlorinated and hydrogenated matrices (58 %). The developed correction method improves the measured values. It may be extended to 0,45 density, heterogeneous drums. (author)

Mass spectrometry in clinical chemistry

International Nuclear Information System (INIS)

Pettersen, J.E.

1977-01-01

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

The influence of surfactant on mass transfer coefficients in evaporation of volatile organic compound from water basin

Directory of Open Access Journals (Sweden)

Bunyakan, C.

2002-04-01

Full Text Available Volatile organic compounds (VOCs have been found in wastewater of many chemical industries. Evaporation of VOCs from open water basin in waste treatment facilities causes air-pollution and has been regulated in many countries. Reduction or prevention of VOCs evaporation from open water basin is then necessary. The aim of this research was to investigate the influence of surface film generated by an insoluble surfactant on the mass transfer coefficient of VOCs evaporating from water. Hexadecanol and octadecanol were used as surfactant in this investigation with the amount in the range of 0 to 35 μg/cm2 and 0 to 25 μg/cm2, respectively. The VOCs used in this study were methanol, acetone, methyl ethyl ketone and toluene. The experimental results showed that the surfactant film can reduce the gas film and liquid coefficients by 56 and 80 %, respectively. The suitable amounts of the surfactant were 25 μg/cm2 for hexadecanol and 15 μg/cm2 for octadecanol. From this investigation we can conclude that covering the water surface with a film of hexadecanol or octadecanol could significantly reduce the VOCs evaporation rate.Finally, the empirical equations correlating gas film and liquid film coefficient to amount of surfactants were developed and verified against the experimental data. The predicted values of the overall mass transfer coefficients, obtained by using these empirical equations, were in good agreement with the measured values. Thus the empirical equations of mass transfer coefficients developed in this work can be used to predict the evaporation rates of VOCs from water surface covered by hexadecanol or octadecanol film.

Modelling of catalytic oxidation of NH3 and reduction of NO on limestone during sulphur capture

DEFF Research Database (Denmark)

Kiil, Søren; Bhatia, Suresh K.; Dam-Johansen, Kim

1996-01-01

activity with respect to each species involved. An existing particle model, the Grain-Micrograin Model, which simulates sulphur capture on limestone under oxidizing conditions is considered in the modelling. Simulation results in good qualitative agreement with experimental data are obtained here......A theoretical study of the complex transient system of simultaneous sulphur capture and catalytic reactions of N-containing compounds taking place on a single limestone particle is conducted. The numerical technique developed previously by the authors (Kiil et al. 1994) based on collocation...... for the catalytic chemistry of NH3 during simultaneous sulphur capture on a Stevns Chalk particle. The reduction of NO by NH3 over CaSO4 (which is the product of the reaction between SO2, O2 and limestone) was found to be important because this reaction could explain the change in selectivity with increased solid...

NOx reduction using amine reclaimer wastes (ARW) generated in post combustion CO2 capture

DEFF Research Database (Denmark)

Botheju, Deshai; Glarborg, Peter; Tokheim, Lars-Andre

2012-01-01

Amine reclaimer wastes (ARW) generated in CO2 capture processes demand suitable disposal means. Such wastes contain remaining amine, NH3 and other degradation compounds. This study investigated the potential of using ARW as a NOx reducing agent, under laboratory conditions in a flow reactor....../NO ratios (waste product, together with its demonstrated NOx reduction capability and its calorific value contribution, makes it attractive as an additive...

Carbon captured from the air

International Nuclear Information System (INIS)

Keith, D.

2008-01-01

This article presented an innovative way to achieve the efficient capture of atmospheric carbon. A team of scientists from the University of Calgary's Institute for Sustainable Energy, Environment and Economy have shown that it is possible to reduce carbon dioxide (CO 2 ) using a simple machine that can capture the trace amount of CO 2 present in ambient air at any place on the planet. The thermodynamics of capturing the small concentrations of CO 2 from the air is only slightly more difficult than capturing much larger concentrations of CO 2 from power plants. The research is significant because it offers a way to capture CO 2 emissions from transportation sources such as vehicles and airplanes, which represent more than half of the greenhouse gases emitted on Earth. The energy efficient and cost effective air capture technology could complement other approaches for reducing emissions from the transportation sector, such as biofuels and electric vehicles. Air capture differs from carbon capture and storage (CCS) technology used at coal-fired power plants where CO 2 is captured and pipelined for permanent storage underground. Air capture can capture the CO 2 that is present in ambient air and store it wherever it is cheapest. The team at the University of Calgary showed that CO 2 could be captured directly from the air with less than 100 kWhrs of electricity per tonne of CO 2 . A custom-built tower was able to capture the equivalent of 20 tonnes per year of CO 2 on a single square meter of scrubbing material. The team devised a way to use a chemical process from the pulp and paper industry to cut the energy cost of air capture in half. Although the technology is only in its early stage, it appears that CO 2 could be captured from the air with an energy demand comparable to that needed for CO 2 capture from conventional power plants, but costs will be higher. The simple, reliable and scalable technology offers an opportunity to build a commercial-scale plant. 1 fig

Ripening-dependent metabolic changes in the volatiles of pineapple (Ananas comosus (L.) Merr.) fruit: I. Characterization of pineapple aroma compounds by comprehensive two-dimensional gas chromatography-mass spectrometry.

Science.gov (United States)

Steingass, Christof Björn; Carle, Reinhold; Schmarr, Hans-Georg

2015-03-01

Qualitative ripening-dependent changes of pineapple volatiles were studied via headspace solid-phase microextraction and analyzed by comprehensive two-dimensional gas chromatography quadrupole mass spectrometry (HS-SPME-GC×GC-qMS). Early green-ripe stage, post-harvest ripened, and green-ripe fruits at the end of their commercial shelf-life were compared to air-freighted pineapples harvested at full maturity. In total, more than 290 volatiles could be identified by mass spectrometry and their linear retention indices. The majority of compounds comprise esters (methyl and ethyl esters of saturated and unsaturated fatty acids, acetates), terpenes, alcohols, aldehydes, 2-ketones, free fatty acids, and miscellaneous γ- and δ-lactones. The structured separation space obtained by GC×GC allowed revealing various homologous series of compound classes as well as clustering of sesquiterpenes. Post-harvest ripening increased the diversity of the volatile profile compared to both early green-ripe maturity stages and on-plant ripened fruits.

Capture by colour: evidence for dimension-specific singleton capture.

Science.gov (United States)

Harris, Anthony M; Becker, Stefanie I; Remington, Roger W

2015-10-01

Previous work on attentional capture has shown the attentional system to be quite flexible in the stimulus properties it can be set to respond to. Several different attentional "modes" have been identified. Feature search mode allows attention to be set for specific features of a target (e.g., red). Singleton detection mode sets attention to respond to any discrepant item ("singleton") in the display. Relational search sets attention for the relative properties of the target in relation to the distractors (e.g., redder, larger). Recently, a new attentional mode was proposed that sets attention to respond to any singleton within a particular feature dimension (e.g., colour; Folk & Anderson, 2010). We tested this proposal against the predictions of previously established attentional modes. In a spatial cueing paradigm, participants searched for a colour target that was randomly either red or green. The nature of the attentional control setting was probed by presenting an irrelevant singleton cue prior to the target display and assessing whether it attracted attention. In all experiments, the cues were red, green, blue, or a white stimulus rapidly rotated (motion cue). The results of three experiments support the existence of a "colour singleton set," finding that all colour cues captured attention strongly, while motion cues captured attention only weakly or not at all. Notably, we also found that capture by motion cues in search for colour targets was moderated by their frequency; rare motion cues captured attention (weakly), while frequent motion cues did not.

Materials For Gas Capture, Methods Of Making Materials For Gas Capture, And Methods Of Capturing Gas

KAUST Repository

Polshettiwar, Vivek

2013-06-20

In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, embodiments of the present disclosure, in one aspect, relate to materials that can be used for gas (e.g., CO.sub.2) capture, methods of making materials, methods of capturing gas (e.g., CO.sub.2), and the like, and the like.

CO 2 Capture from Dilute Gases as a Component of Modern Global Carbon Management

KAUST Repository

Jones, Christopher W.

2011-01-01

The growing atmospheric CO2 concentration and its impact on climate have motivated widespread research and development aimed at slowing or stemming anthropogenic carbon emissions. Technologies for carbon capture and sequestration (CCS) employing mass separating agents that extract and purify CO2 from flue gas emanating from large point sources such as fossil fuel-fired electricity-generating power plants are under development. Recent advances in solvents, adsorbents, and membranes for postcombust- ion CO 2 capture are described here. Specifically, room-temperature ionic liquids, supported amine materials, mixed matrix and facilitated transport membranes, and metal-organic framework materials are highlighted. In addition, the concept of extracting CO2 directly from ambient air (air capture) as a means of reducing the global atmospheric CO2 concentration is reviewed. For both conventional CCS from large point sources and air capture, critical research needs are identified and discussed. © Copyright 2011 by Annual Reviews. All rights reserved.

CO 2 Capture from Dilute Gases as a Component of Modern Global Carbon Management

KAUST Repository

Jones, Christopher W.

2011-07-15

The growing atmospheric CO2 concentration and its impact on climate have motivated widespread research and development aimed at slowing or stemming anthropogenic carbon emissions. Technologies for carbon capture and sequestration (CCS) employing mass separating agents that extract and purify CO2 from flue gas emanating from large point sources such as fossil fuel-fired electricity-generating power plants are under development. Recent advances in solvents, adsorbents, and membranes for postcombust- ion CO 2 capture are described here. Specifically, room-temperature ionic liquids, supported amine materials, mixed matrix and facilitated transport membranes, and metal-organic framework materials are highlighted. In addition, the concept of extracting CO2 directly from ambient air (air capture) as a means of reducing the global atmospheric CO2 concentration is reviewed. For both conventional CCS from large point sources and air capture, critical research needs are identified and discussed. © Copyright 2011 by Annual Reviews. All rights reserved.

The CO{sub 2} capture performance of a high-intensity vortex spray scrubber

Energy Technology Data Exchange (ETDEWEB)

Javed, K.H.; Mahmud, T.; Purba, E. [University of Leeds, Leeds (United Kingdom)

2010-08-15

The present study focuses on the enhancement of CO{sub 2} capture efficiency using a high-intensity vortex spray scrubber by imparting swirl to the gas flow, which has the ability to augment the rates of heat and mass transfer. Experimental investigations into the reactive absorption of CO{sub 2} from a mixture of air-CO{sub 2} into an aqueous solution of NaOH in a laboratory-scale counter-current spray scrubber have been carried out. The mass transfer characteristics, in terms of the overall gas phase mass transfer coefficient (K{sub g}a) were investigated for both the swirling and the non-swirling (axial) gas flows through the scrubber in order to quantify the effect of swirl. The effects of the gas/liquid flow rates, flow arrangements, scrubber height and spray nozzle type on the CO{sub 2} capture performance were examined. For both the axial and the swirling flows, the K{sub g}a increases initially with increasing gas flow rate up to a certain limit, beyond which it becomes essentially constant, whereas the K{sub g}a increases continuously with the liquid flow rate within the measured range. The counter-current gas-droplets flow provides higher mass transfer rates compared with those in co-current flow. The K{sub g}a deceases with the increase in the tower height. The spray nozzle producing finer droplets provides enhanced mass transfer rates. It is found that imparting swirl in the gas flow enhances the K(g)a up to around 49% compared with that in axial flows.

CO2 Capture by Absorption with Potassium Carbonate

Energy Technology Data Exchange (ETDEWEB)

Gary T. Rochelle; Marcus Hilliard; Eric Chen; Babatunde Oyenekan; Ross Dugas; John McLees; Andrew Sexton; Daniel Ellenberger

2005-10-26

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. Modeling of stripper performance suggests that vacuum stripping may be an attractive configuration for all solvents. Flexipac 1Y structured packing performs in the absorber as expected. It provides twice as much mass transfer area as IMTP No.40 dumped packing. Independent measurements of CO{sub 2} solubility give a CO{sub 2} loading that is 20% lower than that Cullinane's values with 3.6 m PZ at 100-120 C. The effective mass transfer coefficient (K{sub G}) in the absorber with 5 m K/2.5 m PZ appears to be 0 to 30% greater than that of 30 wt% MEA.

ALLocator: an interactive web platform for the analysis of metabolomic LC-ESI-MS datasets, enabling semi-automated, user-revised compound annotation and mass isotopomer ratio analysis.

Science.gov (United States)

Kessler, Nikolas; Walter, Frederik; Persicke, Marcus; Albaum, Stefan P; Kalinowski, Jörn; Goesmann, Alexander; Niehaus, Karsten; Nattkemper, Tim W

2014-01-01

Adduct formation, fragmentation events and matrix effects impose special challenges to the identification and quantitation of metabolites in LC-ESI-MS datasets. An important step in compound identification is the deconvolution of mass signals. During this processing step, peaks representing adducts, fragments, and isotopologues of the same analyte are allocated to a distinct group, in order to separate peaks from coeluting compounds. From these peak groups, neutral masses and pseudo spectra are derived and used for metabolite identification via mass decomposition and database matching. Quantitation of metabolites is hampered by matrix effects and nonlinear responses in LC-ESI-MS measurements. A common approach to correct for these effects is the addition of a U-13C-labeled internal standard and the calculation of mass isotopomer ratios for each metabolite. Here we present a new web-platform for the analysis of LC-ESI-MS experiments. ALLocator covers the workflow from raw data processing to metabolite identification and mass isotopomer ratio analysis. The integrated processing pipeline for spectra deconvolution "ALLocatorSD" generates pseudo spectra and automatically identifies peaks emerging from the U-13C-labeled internal standard. Information from the latter improves mass decomposition and annotation of neutral losses. ALLocator provides an interactive and dynamic interface to explore and enhance the results in depth. Pseudo spectra of identified metabolites can be stored in user- and method-specific reference lists that can be applied on succeeding datasets. The potential of the software is exemplified in an experiment, in which abundance fold-changes of metabolites of the l-arginine biosynthesis in C. glutamicum type strain ATCC 13032 and l-arginine producing strain ATCC 21831 are compared. Furthermore, the capability for detection and annotation of uncommon large neutral losses is shown by the identification of (γ-)glutamyl dipeptides in the same strains

ALLocator: an interactive web platform for the analysis of metabolomic LC-ESI-MS datasets, enabling semi-automated, user-revised compound annotation and mass isotopomer ratio analysis.

Directory of Open Access Journals (Sweden)

Nikolas Kessler

Full Text Available Adduct formation, fragmentation events and matrix effects impose special challenges to the identification and quantitation of metabolites in LC-ESI-MS datasets. An important step in compound identification is the deconvolution of mass signals. During this processing step, peaks representing adducts, fragments, and isotopologues of the same analyte are allocated to a distinct group, in order to separate peaks from coeluting compounds. From these peak groups, neutral masses and pseudo spectra are derived and used for metabolite identification via mass decomposition and database matching. Quantitation of metabolites is hampered by matrix effects and nonlinear responses in LC-ESI-MS measurements. A common approach to correct for these effects is the addition of a U-13C-labeled internal standard and the calculation of mass isotopomer ratios for each metabolite. Here we present a new web-platform for the analysis of LC-ESI-MS experiments. ALLocator covers the workflow from raw data processing to metabolite identification and mass isotopomer ratio analysis. The integrated processing pipeline for spectra deconvolution "ALLocatorSD" generates pseudo spectra and automatically identifies peaks emerging from the U-13C-labeled internal standard. Information from the latter improves mass decomposition and annotation of neutral losses. ALLocator provides an interactive and dynamic interface to explore and enhance the results in depth. Pseudo spectra of identified metabolites can be stored in user- and method-specific reference lists that can be applied on succeeding datasets. The potential of the software is exemplified in an experiment, in which abundance fold-changes of metabolites of the l-arginine biosynthesis in C. glutamicum type strain ATCC 13032 and l-arginine producing strain ATCC 21831 are compared. Furthermore, the capability for detection and annotation of uncommon large neutral losses is shown by the identification of (γ-glutamyl dipeptides in

Response of the oral mucosa to porphyrin mediated boron neutron capture therapy

International Nuclear Information System (INIS)

Morris, G.M.

2003-01-01

Pre-clinical studies are now in progress to develop boron neutron capture therapy (BNCT) modalities for the treatment of head and neck carcinomas. BNCT is a bimodal therapy which involves the administration of a boron-10 enriched compound, that accumulates preferentially in tumours, prior to irradiation with low energy neutrons. These neutrons are captured by boron-10 atoms to produce a highly localised radiation exposure. More recently, it has been demonstrated that various boronated porphyrins can target a variety of tumours. Of the porphyrins evaluated to date, copper tetracarboranylphenyl porphyrin (CuTCPH) is a strong candidate for potential clinical evaluation. It has extremely high specificity for a variety of tumour models. Therapeutic efficacy of CuTCPH mediated BNCT has been demonstrated in pre-clinical studies using the murine EMT-6 carcinoma model. In the present investigation the response of the oral mucosa to CuTCPH mediated boron neutron capture (BNC) irradiation was assessed using a standard rat model (ventral tongue). Single exposure irradiation was carried out on the thermal neutron beam at the Brookhaven Medical Research Reactor, at 3 days after the final injection of the boronated porphyrin. The impact of CuTCPH mediated BNC irradiation on oral mucosa at therapeutically effective exposure times, assessed using the ventral tongue model, was minimal. This was primarily due to the fact that blood boron levels (from CuTCPH) were very low at the time of irradiation. Analysis of the dose-effect data for CuTCPH gave a compound biological effectiveness (CBE) factor of 2.5. It can be concluded that, although, the CBE factor (calculated using blood boron concentrations) was relatively high, CuTCPH mediated BNC irradiation should not cause significant damage at clinically relevant radiation doses. This is because blood boron levels would be very low at the time of irradiation

Interatomic Coulombic electron capture

International Nuclear Information System (INIS)

Gokhberg, K.; Cederbaum, L. S.

2010-01-01

In a previous publication [K. Gokhberg and L. S. Cederbaum, J. Phys. B 42, 231001 (2009)] we presented the interatomic Coulombic electron capture process--an efficient electron capture mechanism by atoms and ions in the presence of an environment. In the present work we derive and discuss the mechanism in detail. We demonstrate thereby that this mechanism belongs to a family of interatomic electron capture processes driven by electron correlation. In these processes the excess energy released in the capture event is transferred to the environment and used to ionize (or to excite) it. This family includes the processes where the capture is into the lowest or into an excited unoccupied orbital of an atom or ion and proceeds in step with the ionization (or excitation) of the environment, as well as the process where an intermediate autoionizing excited resonance state is formed in the capturing center which subsequently deexcites to a stable state transferring its excess energy to the environment. Detailed derivation of the asymptotic cross sections of these processes is presented. The derived expressions make clear that the environment assisted capture processes can be important for many systems. Illustrative examples are presented for a number of model systems for which the data needed to construct the various capture cross sections are available in the literature.

Biological models in vivo for boron neutronic capture studies as tumors therapy

International Nuclear Information System (INIS)

Kreimann, Erica L.; Dagrosa, Maria A.; Schwint, Amanda E.; Itoiz, Maria E.; Pisarev, Mario A.; Farias, Silvia S.; Garavaglia, Ricardo N.; Batistoni, Daniel A.

1999-01-01

The use of experimental models for Boron Neutronic Capture studies as Tumors Therapy have as two main objectives: 1) To contribute to the basic knowledge of the biological mechanisms involved to increase the method therapeutical advantage, and 2) To explore the possible application of this therapeutic method to other pathologies. In this frame it was studied the carcinogenesis model of hamster cheek pouch, a type of human buccal cancer. Biodistribution studies of boron compound were performed in tumor, blood and in different precancerous and normal tissues as well as BNCT studies. Results validated this method for BNCT studies and show the capacity of the oral mucosa tumors of selectively concentrate the boron compound, showing a deleterious clear effect on the tumor after 24 hours with BNCT treatment. (author)

MassTRIX: mass translator into pathways.

Science.gov (United States)

Suhre, Karsten; Schmitt-Kopplin, Philippe

2008-07-01

Recent technical advances in mass spectrometry (MS) have brought the field of metabolomics to a point where large numbers of metabolites from numerous prokaryotic and eukaryotic organisms can now be easily and precisely detected. The challenge today lies in the correct annotation of these metabolites on the basis of their accurate measured masses. Assignment of bulk chemical formula is generally possible, but without consideration of the biological and genomic context, concrete metabolite annotations remain difficult and uncertain. MassTRIX responds to this challenge by providing a hypothesis-driven approach to high precision MS data annotation. It presents the identified chemical compounds in their genomic context as differentially colored objects on KEGG pathway maps. Information on gene transcription or differences in the gene complement (e.g. samples from different bacterial strains) can be easily added. The user can thus interpret the metabolic state of the organism in the context of its potential and, in the case of submitted transcriptomics data, real enzymatic capacities. The MassTRIX web server is freely accessible at http://masstrix.org.

Dispersive liquid-liquid microextraction and gas chromatography accurate mass spectrometry for extraction and non-targeted profiling of volatile and semi-volatile compounds in grape marc distillates.

Science.gov (United States)

Fontana, Ariel; Rodríguez, Isaac; Cela, Rafael

2018-04-20

The suitability of dispersive liquid-liquid microextraction (DLLME) and gas chromatography accurate mass spectrometry (GC-MS), based on a time-of-flight (TOF) MS analyzer and using electron ionization (EI), for the characterization of volatile and semi-volatile profiles of grape marc distillates (grappa) are evaluated. DLLME conditions are optimized with a selection of compounds, from different chemical families, present in the distillate spirit. Under final working conditions, 2.5 mL of sample and 0.5 mL of organic solvents are consumed in the sample preparation process. The absolute extraction efficiencies ranged from 30 to 100%, depending on the compound. For the same sample volume, DLLME provided higher responses than solid-phase microextraction (SPME) for most of the model compounds. The GC-EI-TOF-MS records of grappa samples were processed using a data mining non-targeted search algorithm. In this way, chromatographic peaks and accurate EI-MS spectra of sample components were linked. The identities of more than 140 of these components are proposed from comparison of their accurate spectra with those in a low resolution EI-MS database, accurate masses of most intense fragment ions of known structure, and available chromatographic retention index. The use of chromatographic and spectral data, associated to the set of components mined from different grappa samples, for multivariate analysis purposes is also illustrated in the study. Copyright © 2018 Elsevier B.V. All rights reserved.

MALDI-TOF mass spectrometry analysis of small molecular weight compounds (under 10 KDa) as biomarkers of rat hearts undergoing arecoline challenge.

Science.gov (United States)

Chen, Tung-Sheng; Chang, Mu-Hsin; Kuo, Wei-Wen; Lin, Yueh-Min; Yeh, Yu-Lan; Day, Cecilia Hsuan; Lin, Chien-Chung; Tsai, Fuu-Jen; Tsai, Chang-Hai; Huang, Chih-Yang

2013-04-01

Statistical and clinical reports indicate that betel nut chewing is strongly associated with progression of oral cancer because some ingredients in betel nuts are potential cancer promoters, especially arecoline. Early diagnosis for cancer biomarkers is the best strategy for prevention of cancer progression. Several methods are suggested for investigating cancer biomarkers. Among these methods, gel-based proteomics approach is the most powerful and recommended tool for investigating biomarkers due to its high-throughput. However, this proteomics approach is not suitable for screening biomarkers with molecular weight under 10 KDa because of the characteristics of gel electrophoresis. This study investigated biomarkers with molecular weight under 10 KDa in rats with arecoline challenge. The centrifuging vials with membrane (10 KDa molecular weight cut-off) played a crucial role in this study. After centrifuging, the filtrate (containing compounds with molecular weight under 10 KDa) was collected and spotted on a sample plate for MALDI-TOF mass spectrometry analysis. Compared to control, three extra peaks (m/z values were 1553.1611, 1668.2097 and 1740.1832, respectively) were found in sera and two extra peaks were found in heart tissue samples (408.9719 and 524.9961, respectively). These small compounds should play important roles and may be potential biomarker candidates in rats with arecoline. This study successfully reports a mass-based method for investigating biomarker candidates with small molecular weight in different types of sample (including serum and tissue). In addition, this reported method is more time-efficient (1 working day) than gel-based proteomics approach (5~7 working days).

Cytotoxic Compounds from Aloe megalacantha

Directory of Open Access Journals (Sweden)

Negera Abdissa

2017-07-01

Full Text Available Phytochemical investigation of the ethyl acetate extract of the roots of Aloe megalacantha led to the isolation of four new natural products—1,8-dimethoxynepodinol (1, aloesaponarin III (2, 10-O-methylchrysalodin (3 and methyl-26-O-feruloyl-oxyhexacosanate (4—along with ten known compounds. All purified metabolites were characterized by NMR, mass spectrometric analyses and comparison with literature data. The isolates were evaluated for their cytotoxic activity against a human cervix carcinoma cell line KB-3-1 and some of them exhibited good activity, with aloesaponarin II (IC50 = 0.98 µM being the most active compound.

Determination of pharmaceutical compounds in surface- and ground-water samples by solid-phase extraction and high-performance liquid chromatography-electrospray ionization mass spectrometry

Science.gov (United States)

Cahill, J.D.; Furlong, E.T.; Burkhardt, M.R.; Kolpin, D.; Anderson, L.G.

2004-01-01

Commonly used prescription and over-the-counter pharmaceuticals are possibly present in surface- and ground-water samples at ambient concentrations less than 1 μg/L. In this report, the performance characteristics of a combined solid-phase extraction isolation and high-performance liquid chromatography–electrospray ionization mass spectrometry (HPLC–ESI-MS) analytical procedure for routine determination of the presence and concentration of human-health pharmaceuticals are described. This method was developed and used in a recent national reconnaissance of pharmaceuticals in USA surface waters. The selection of pharmaceuticals evaluated for this method was based on usage estimates, resulting in a method that contains compounds from diverse chemical classes, which presents challenges and compromises when applied as a single routine analysis. The method performed well for the majority of the 22 pharmaceuticals evaluated, with recoveries greater than 60% for 12 pharmaceuticals. The recoveries of angiotensin-converting enzyme inhibitors, a histamine (H2) receptor antagonist, and antihypoglycemic compound classes were less than 50%, but were retained in the method to provide information describing the potential presence of these compounds in environmental samples and to indicate evidence of possible matrix enhancing effects. Long-term recoveries, evaluated from reagent-water fortifications processed over 2 years, were similar to initial method performance. Method detection limits averaged 0.022 μg/L, sufficient for expected ambient concentrations. Compound-dependent matrix effects on HPLC/ESI-MS analysis, including enhancement and suppression of ionization, were observed as a 20–30% increase in measured concentrations for three compounds and greater than 50% increase for two compounds. Changing internal standard and more frequent ESI source maintenance minimized matrix effects. Application of the method in the national survey demonstrates that several

Extensive Use of Gas Chromatography – Mass Spectrometry for the Characterization of the Effects of Radiation Treatment of Wastewater

Energy Technology Data Exchange (ETDEWEB)

Virgolici, M.; Stanculescu, I. R.; Ponta, C. C.; Moise, I. V.; Cutrubinis, M.; Negut, D. C.; Manea, M. M.; Alexandru, M. [Horia Hulubei National Institute of Physics and Nuclear Engineering, IRASM Radiation Processing Center, Magurele, Ilfov (Romania)

2012-07-01

An ongoing radiolytic study is currently carried out on model wastewater samples spiked with organochlorine insecticides (e.g. hexachlorobenzene (HCB)) and polychlorinated byphenils (PCB, e.g. PCB 52). To identify the most convenient irradiation conditions for wastewater treatment, samples were irradiated at different doses: 1.3, 4.5 and 13 kGy (1.3 kGy/h dose rate). The dependence of organochlorine insecticides and PCB’s concentration of the absorbed dose was monitored by gas chromatography (GC) with simultaneous micro electron capture detection (ECD) and mass spectrometric detection (MS, in single ion monitoring (SIM) mode); using ISO 6468:1996 protocols for sample preparation. The molecular structure confirmation of target compounds and possible persistent organic pollutant (POP) radiolysis products was also performed with the mass spectrometric detector in SCAN mode. A molecular modelling study is developed to predict the most probable radiolysis products and it is correlated with the GC/MS results to suggest some preferential radiolysis pathways. (author)

Extensive Use of Gas Chromatography – Mass Spectrometry for the Characterization of the Effects of Radiation Treatment of Wastewater

International Nuclear Information System (INIS)

Virgolici, M.; Stanculescu, I.R.; Ponta, C.C.; Moise, I.V.; Cutrubinis, M.; Negut, D.C.; Manea, M.M.; Alexandru, M.

2012-01-01

An ongoing radiolytic study is currently carried out on model wastewater samples spiked with organochlorine insecticides (e.g. hexachlorobenzene (HCB)) and polychlorinated byphenils (PCB, e.g. PCB 52). To identify the most convenient irradiation conditions for wastewater treatment, samples were irradiated at different doses: 1.3, 4.5 and 13 kGy (1.3 kGy/h dose rate). The dependence of organochlorine insecticides and PCB’s concentration of the absorbed dose was monitored by gas chromatography (GC) with simultaneous micro electron capture detection (ECD) and mass spectrometric detection (MS, in single ion monitoring (SIM) mode); using ISO 6468:1996 protocols for sample preparation. The molecular structure confirmation of target compounds and possible persistent organic pollutant (POP) radiolysis products was also performed with the mass spectrometric detector in SCAN mode. A molecular modelling study is developed to predict the most probable radiolysis products and it is correlated with the GC/MS results to suggest some preferential radiolysis pathways. (author)

Some thoughts on tolerance, dose, and fractionation in boron neutron capture therapy

International Nuclear Information System (INIS)

Gahbauer, R.; Goodman, J.; Blue, T.

1988-01-01

Unique to boron neutron capture therapy, the tolerance very strongly depends on the boron concentration in normal brain, skin and blood. If one first considers the ideal situation of a 2 KeV beam and a compound clearing from normal tissues and blood, the tolerance dose to epithermal beams relates to the maximum tolerated capture gamma dose and capture high LET dose, H (n,gamma)D and N(n,p) 14 C. The authors can relate this gamma and high LET dose to known clinical experience. Assuming gamma and high LET dose ratios as given by Fairchild and Bond, one may first choose a clearly safe high LET whole brain dose and calculate the unavoidably resulting gamma dose. To a first approximation 500 cGy of high LET dose results in 3,000 cGy gamma dose. One can speculate that this approximates the tolerance of whole brain to the 2 KeV beam with no contributing boron dose if the radiation is fractionated. It would clearly be beyond tolerance in a single fraction where most therapists would be uncomfortable to deliver even one third of the above doses

Carbon captured from the air

Energy Technology Data Exchange (ETDEWEB)

Keith, D. [Calgary Univ., AB (Canada)

2008-10-15

This article presented an innovative way to achieve the efficient capture of atmospheric carbon. A team of scientists from the University of Calgary's Institute for Sustainable Energy, Environment and Economy have shown that it is possible to reduce carbon dioxide (CO{sub 2}) using a simple machine that can capture the trace amount of CO{sub 2} present in ambient air at any place on the planet. The thermodynamics of capturing the small concentrations of CO{sub 2} from the air is only slightly more difficult than capturing much larger concentrations of CO{sub 2} from power plants. The research is significant because it offers a way to capture CO{sub 2} emissions from transportation sources such as vehicles and airplanes, which represent more than half of the greenhouse gases emitted on Earth. The energy efficient and cost effective air capture technology could complement other approaches for reducing emissions from the transportation sector, such as biofuels and electric vehicles. Air capture differs from carbon capture and storage (CCS) technology used at coal-fired power plants where CO{sub 2} is captured and pipelined for permanent storage underground. Air capture can capture the CO{sub 2} that is present in ambient air and store it wherever it is cheapest. The team at the University of Calgary showed that CO{sub 2} could be captured directly from the air with less than 100 kWhrs of electricity per tonne of CO{sub 2}. A custom-built tower was able to capture the equivalent of 20 tonnes per year of CO{sub 2} on a single square meter of scrubbing material. The team devised a way to use a chemical process from the pulp and paper industry to cut the energy cost of air capture in half. Although the technology is only in its early stage, it appears that CO{sub 2} could be captured from the air with an energy demand comparable to that needed for CO{sub 2} capture from conventional power plants, but costs will be higher. The simple, reliable and scalable technology

Device for collecting chemical compounds and related methods

Science.gov (United States)

Scott, Jill R.; Groenewold, Gary S.; Rae, Catherine

2013-01-01

A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from the fixed surfaces so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

Some methods for labelling organic compounds by deuterium

International Nuclear Information System (INIS)

Moustapha, C.

1988-01-01

The rapid growth of knowledge in the fields of biochemistry, physiology, and molecular biology reflects to a considerable degree the utilization of stable isotopes (specially deuterium) in the study of chemical reactions and fragmentation mechanisms in mass spectrometry, as well as in the pharmacological and biological studies. Organic compounds maybe labelled by deuterium through classic organic reactions by using special deuterated solvents and reagents. This article discusses some reactions, with examples on how to prepare labelled compounds with high isotopic purety. These reactions are: exchange reactions in acid and alkaline media (the exchange in the chromatographic column in liquid and gas phases, the exchange in homogenous medium), reduction reactions of functional groups as well as saturation of the double bounds by deuterium using hydrogenation catalystes, electrochemical reactions using KOLBE, and photochemical reactions. This article also deals with spectroscopic properties of deuterium and the methods which are used to identify its compounds such as infrared, nuclear magnetic resonance, and mass spectroscopy. 37 refs., 2 figs

Determination of selected quaternary ammonium compounds by liquid chromatography with mass spectrometry. Part II. Application to sediment and sludge samples in Austria

International Nuclear Information System (INIS)

Martinez-Carballo, Elena; Gonzalez-Barreiro, Carmen; Sitka, Andrea; Kreuzinger, Norbert; Scharf, Sigrid; Gans, Oliver

2007-01-01

Soxhlet extraction and high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry detection (MS/MS) was used for the determination of selected quaternary ammonium compounds (QACs) in solid samples. The method was applied for the determination of alkyl benzyl, dialkyl and trialkyl quaternary ammonium compounds in sediment and sludge samples in Austria. The overall method quantification limits range from 0.6 to 3 μg/kg for sediments and from 2 to 5 μg/kg for sewage sludges. Mean recoveries between 67% and 95% are achieved. In general sediments were especially contaminated by C12 chain benzalkonium chloride (BAC-C12) as well as by the long C-chain dialkyldimethylammonium chloride (DDAC-C18) with a maximum concentration of 3.6 mg/kg and 2.1 mg/kg, respectively. Maxima of 27 mg/kg for DDAC-C10, 25 mg/kg for BAC-C12 and 23 mg/kg for BAC-C14 were determined for sludge samples. The sums of the 12 selected target compounds range from 22 mg/kg to 103 mg/kg in the sludge samples. - The presence of quaternary ammonium surfactants in sediment and sludge samples is reported for the first time in Austria

Numerical prediction of CO2 capture process by a single droplet in alkaline spray

International Nuclear Information System (INIS)

Chen, Wei-Hsin; Tsai, Ming-Hang; Hung, Chen-I

2013-01-01

Highlights: • CO 2 capture by a single droplet is studied numerically. • Three different initial pH values of 10, 11, and 12 in the droplet are considered. • The initial pH value has a significant influence on the capture process. • The carbon capture rate is raised as the initial pH value rises. • The droplet with the initial pH value of 12 is feasible to perform CO 2 capture. - Abstract: Carbon dioxide captured by single droplets in sprays plays a fundamental role in reducing greenhouse gas emissions. This study focuses on CO 2 capture processes in single droplets in alkaline sprays using a numerical method. Three different initial pH values of 10, 11, and 12 in the droplet are considered. The capture behavior in the absence of chemical dissociation is also investigated for comparison. The predictions suggest that the chemical dissociation in the droplet substantially elongates the CO 2 capture process and the mass diffusion is the controlling mechanism of CO 2 capture process. For the chemical absorption, the final CO 2 capture amount by the droplet is mainly determined by HCO 3 - which is significantly influenced by the initial pH value. An increase in initial pH value raises the carbon capture amount by the droplet. The mean concentration of CO 3 2- is highly related to the variation of mean pH value, but its concentration is by far lower than those of H 2 O⋅CO 2 and HCO 3 - . Corresponding to the initial pH values of 10, 11, and 12, the times required for turning the basic droplet to the acidic one are in the orders of 10, 100, and 1000 ms. On account of larger carbon capture amount and shorter absorption period at a higher initial pH value, the carbon capture rate is lifted as the initial pH value rises, and CO 2 capture by droplets at the initial pH value of 12 is better than those at 10 and 11

Development Of An In Situ Passive Sampler For The Detection And Remediation of Explosive Compounds

Science.gov (United States)

2016-06-07

including high performance liquid chromatography (HPLC), gas chromatography mass spectrometry (GCMS) and isotope ratio mass spectrometry ( IRMS ) as...GCMS) and isotope ratio mass spectrometry ( IRMS ) as summarized in St. George et al., 2010 and Smith et al., 2013, 2014. Depuration rates will be...TNT and RDX for the depuration compounds and unlabeled compounds in the ambient environment. These will be quantified as above by GCMS and IRMS . 2015

Matrix-assisted laser desorption fourier transform mass spectrometry for biological compounds

Energy Technology Data Exchange (ETDEWEB)

Hettich, R.; Buchanan, M.

1990-01-01

The recent development of matrix-assisted UV laser desorption (LD) mass spectrometry has made possible the ionization and detection of extremely large molecules (with molecular weights exceeding 100,000 Daltons). This technique has generated enormous interest in the biological community for the direct examination of large peptides and oligonucleotides. Although this matrix-assisted ionization method has been developed and used almost exclusively with time-of-flight (TOF) mass spectrometers, research is currently in progress to demonstrate this technique with trapped ion mass spectrometers, such as Fourier transform ion cyclotron resonance mass spectrometry (FTMS). The potential capabilities of FTMS for wide mass range, high resolution measurement, and ion trapping experiments suggest that this instrumental technique should be useful for the detailed structural characterization of large ions generated by the matrix-assisted technique. We have recently demonstrated that matrix-assisted ultraviolet laser desorption can be successfully used with FTMS for the ionization of small peptides. The objective of this report is to summarize the application and current limitations of matrix-assisted laser desorption FTMS for the characterization of peptides and oligonucleotides at the isomeric level. 4 refs., 3 figs., 2 tabs.

Production and characterization of surface-active compounds from Gordonia amicalis

Directory of Open Access Journals (Sweden)

Ani Beatriz Jackisch-Matsuura

2014-02-01

Full Text Available Two methods were used to make crude preparations of surface-active compounds (SACs produced by Gordonia amicalis grown on the medium containing 1% diesel oil. Using a 2:1 (v/v solution of chloroform:methanol for extraction, Type I SACs were isolated and shown to produce oil in water (O/W emulsions. Type II SACs were isolated by precipitation with ammonium sulfate and produced predominantly water in oil emulsions (W/O. The crude Type I and II preparations were able to produce a significant reduction in the surface tension of water; however, the crude Type II preparation had 10-25 fold higher emulsification activity than the Type I preparation. Both SAC preparations were analyzed by the TLC and each produced two distinct bands with Rf 0.44 and 0.62 and Rf 0.52 and 0.62, respectively. The partially purified SACs were characterized by the ESI(+-MS, FT-IR and NMR. In each one of these fractions, a mixture of 10 oligomers was found consisting of a series of compounds, with masses from 502 to 899, differing in molecular mass by a repeating unit of 44 Daltons. The mass spectra of these compounds did not appear to match other known biosurfactants and could represent a novel class of these compounds.

Aquatic prey capture in snakes: the link between morphology, behavior and hydrodynamics

Science.gov (United States)

Segall, Marion; Herrel, Anthony; Godoy-Diana, Ramiro; Funevol Team; Pmmh Team

2017-11-01