Dissertations / Theses on the topic 'Mass spectroscopy'
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1
Massa, D. L. "Discussion: Spectroscopy and Mass-Loss Diagnostics." Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2008/1782/.
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Rogers, Kevin Shaun. "Laser desorption/laser ionization mass spectroscopy." Thesis, University of Salford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357037.
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Lorenz, Martin. "Matrix-isolation spectroscopy of mass-selected ions." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=962027340.
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Boyce, Kevin Robert. "Improved single ion cyclotron resonance mass spectroscopy." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/42551.
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Natarajan, Vasant. "Penning trap mass spectroscopy at 0.1 ppb." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/28017.
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Cornell, Eric Allin. "Mass spectroscopy using single ion cyclotron resonance." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/13562.
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Bagga, Amit. "Femtosecond Laser Mass Spectroscopy of Cyclic Aromatic Hydrocarbons." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37098.
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Cyclic Aromatic molecules are the subject of continued research due to their highly advantageous characteristics which can be exploited in the areas of pharmaceuticals, material science and nano-electronics. While the defining properties and criteria for a molecule to be considered aromatic are very specific and well established, the degree of aromaticity of these molecules and their corresponding ordering remains a source of continued debate. Given that the macroscopic aromatic properties are fundamentally rooted in the underlying electronic structure and molecular dynamics, these properties can be probed in numerous ways. One such method is to exploit the strong laser field as it pertains to non-linear light-matter interaction. More specifically, the study of photoionization, as a direct resultant effect of strong field light-matter interaction, gives us direct insight into electronic and spatial properties as captured via mass spectroscopy. As a strong-field process, photoionization is effective because the variables that influence its results are also the ones that define aromaticity thus a correlation can be postulated. Other strong field advanced techniques to probe aromacity such as High Harmonic Generation (HHG) have already been successful shown by our group to be effective spectroscopic tools. In this way, photoionization provides supporting evidence to enhance the understanding of these novel spectroscopic tools. This thesis demonstrates that photoionization mass spectroscopy can be used as a probe into the aromaticity order of 5-membered cyclic aromatic molecules. Furthermore, the thesis will show that photoionization results correlate with the previously conducted HHG studies in this area thus further supporting these techniques as sensitive spectroscopic tools into aromaticity. The first part of this thesis describes the characterization of aromatic molecules and the corresponding process to obtain photoionization results that can be correlated to aromaticity. In the second part, these results are compared to the theoretical model and HHG demonstrating consistent results. The third and final component of this thesis describes future work, namely two-colour control of photoionization which is intended to provide greater resolution and variation of photoionization spectra thereby providing a more comprehensive and conclusive understanding of the proposed correlation with aromaticity.
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Parry, Christopher Mark. "Spectroscopy of neutron deficient mass A=130 nuclei." Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313864.
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Cartwright, Peter C. "Mass selective laser photoionisation spectroscopy of copper dimer." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/13333.
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HUTH, THOMAS CARL. "ANALYTICAL MASS SPECTROMETRY WITH A SELECTIVE VACUUM ULTRAVIOLET PHOTOIONIZATION SOURCE." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183916.
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The vacuum ultraviolet molecular hydrogen laser is evaluated as a selective ion source for analytical mass spectrometry of easily-ionized compounds. The types of compounds ionized below the photon energy of 7.8 eV include polynuclear aromatic hydrocarbons, and many amines and nitrogen-containing heterocycles. The latter two categories encompass a large number of pharmaceuticals and drugs of abuse. H₂ laser photoionization produces parent molecular ions only, for all compounds studied thus far. Selectivity of the threshold photoionization process is very high, as compounds within as little as 0.2 eV above the threshold are completely rejected. The ability of the technique to discriminate against interfering matrix components is demonstrated for both simple synthetic and complex "real world" mixtures. Easily interpreted spectra are obtained from simple extracts of spiked coffee, beer, soy sauce, urine and blood serum. The most important interference is shown to be electron impact ionization arising from acceleration of stray electrons in the ion source. Most of this ionization is caused by low-energy secondaries generated when stray primaries are collected by the ion source electrodes. The primaries are produced mainly by interaction of scattered laser radiation with metal surfaces. This interference can be controlled through proper instrumental design.
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Biggs, P. "The study of atmospherically important radicals by mass spectroscopy." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382726.
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Clarke, Nigel J. "Analytical and computational studies in ion trap mass spectroscopy." Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282487.
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Juett, Adrienne Marie 1976. "X-ray spectroscopy of low-mass X-ray binaries." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28371.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.Includes bibliographical references (p. 125-144).
I present high-resolution X-ray grating spectroscopy of neutron stars in low-mass X-ray binaries (LMXBs) using instruments onboard the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission (XMM-Newton). The first part of this thesis concentrates on results from the subset of LMXBs with orbital periods less than an hour, known as ultracompact binaries. Previous low-resolution X-ray spectra of four systems (4U 0614+091, 2S 0918-549, 4U 1543-624, and 4U 1850-087) all contain a broad residual near 0.7 keV which had been attributed to unresolved line emission. I show that this residual is due to an incorrect model of the intervening photoelectric absorption and can be accounted for by allowing a non-standard Ne/O abundance ratio in the intervening material. I propose that there is neon-rich material local to each binary and that the mass donor is a low-mass, neon-rich degenerate dwarf in an ultracompact binary. Follow-up spectroscopy of 2S 0918-549 and 4U 1543-624 with the High Energy Transmission Grating Spectrometer (HETGS) onboard Chandra and the Reflection Grating Spectrometer onboard XMM confirms the excess neutral neon absorption. Interestingly, the Ne/O ratio of 4U 1543-624 varies by a factor of three between the Chandra and XMMobservations, supporting the suggestion that some of the absorption originates local to the binaries. I also present X-ray spectroscopy of another ultracompact binary, the accretion-powered millisecond pulsar XTE J0929-314. No emission or absorption features are found in the high-resolution spectrum of this source, and the neutral absorption edge depths are consistent with the estimated interstellar absorption. The second part of this thesis uses LMXBs as probes of the interstellar medium (ISM).
(cont.) High-resolution X-ray studies of ISM absorption features can provide measurements of the relative abundances and ionization fractions of all the elements from carbon through iron. X- ray studies also probe the ISM on larger scales than is possible in the optical and ultraviolet wavebands. I present high-resolution spectroscopy of the oxygen K-shell ISM absorption edge in seven X-ray binaries using Chandra. The best-fit model consists of two absorption edges and five Gaussian absorption lines and can be explained by the recent theoretical calculations of K-shell absorption by neutral and ionized atomic oxygen. Significant oxygen features from dust or molecular components, suggested in previous studies, are not required by the Chandra spectra. These measurements also probe large-scale properties of the ISM, placing a limit on the velocity dispersion of the neutral lines of less than 200 km s-1 and constraining the interstellar ratio of O II/O I to approximately 0.1 and the ratio of O III/O I to less than 0.1.
by Adrienne Marie Juett.
Ph.D.
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Baturin, Pavlo. "Spectroscopy of Electroproduced Light to Medium Mass Lambda Hypernuclei." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/249.
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The E01-011 experiment at Jefferson Laboratory (JLab) studied light-to-medium mass Lambda hypernuclei via the (e,e'K+) electroproduction reaction. Precise measurement of hypernuclear ground state masses and excitation energies provides information about the nature of hyperon-nucleon interactions. Until recently, hypernuclei were studied at accelerator facilities with intense pi+ and K- meson beams. The poor quality of these beams limited the resolution of the hypernuclear excitation energy spectra to about 1.5 MeV (FWHM). This resolution is not sufficient for resolving the rich structure observed in the excitation spectra. By using a high quality electron beam and employing a new high resolution spectrometer system, this study aims to improve the resolution to a few hundred keV with an absolute precision of about 100 keV for excitation energies. In this work the high-resolution excitation spectra of 12B-Lambda, 7He-Lambda, and 28Al-Lambda hypernuclei are presented. In an attempt to emphasize the presence of the core-excited states we introduced a novel likelihood approach to particle identification (PID) to serve as an alternative to the commonly used standard hard-cut PID. The new method resulted in almost identical missing mass spectra as obtained by the standard approach. An energy resolution of approximately 400-500 keV (FWHM) has been achieved, an unprecedented value in hypernuclear reaction spectroscopy. For 12B-Lambda the core-excited configuration has been clearly observed with significant statistics. The embedded Lambda hyperon increases the excitation energies of the 11B nuclear core by 0.5-1 MeV. The 7He-Lambda spectrum has been observed with significant statistics for the first time. The ground state is bound deeper by roughly 400 keV than currently predicted by theory. Indication for the core-excited doublet, which is unbound in the core itself, is observed. The measurement of 28Al-Lambda provides the first study of a d-shell hypernucleus with sub-MeV resolution. Discrepancies of up to 2 MeV between measured and theoretically predicted binding energies are found. Similar disagreement exists when comparing to the 28Si-Lambda mirror hypernucleus. Also the core-excited structure observed between the major s-, p- and d-shell Lambda orbits is not consistent with the available theoretical calculations. In conclusion, the discrepancies found in this study will provide valuable input for the further development of theoretical models.
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Chen, Haijian. "Automated peak identification for time -of -flight mass spectroscopy." W&M ScholarWorks, 2006. https://scholarworks.wm.edu/etd/1539623489.
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The high throughput capabilities of protein mass fingerprints measurements have made mass spectrometry one of the standard tools for proteomic research, such as biomarker discovery. However, the analysis of large raw data sets produced by the time-of-flight (TOF) spectrometers creates a bottleneck in the discovery process. One specific challenge is the preprocessing and identification of mass peaks corresponding to important biological molecules. The accuracy of mass assignment is another limitation when comparing mass fingerprints with databases.;We have developed an automated peak picking algorithm based on a maximum likelihood approach that effectively and efficiently detects peaks in a time-of-flight secondary ion mass spectrum. This approach produces maximum likelihood estimates of peak positions and amplitudes, and simultaneously develops estimates of the uncertainties in each of these quantities. We demonstrate that a Poisson process is involved for time-of-flight secondary ion mass spectrometry (TOF-SIMS) and the algorithm takes the character of the Poisson noise into account.;Though this peak picking algorithm was initially developed for TOF-SIMS spectra, it can be extended to other types of TOF spectra as soon as the correct noise characteristics are considered. We have developed a peak alignment procedure that aligns peaks in different spectra. This is a crucial step for multivariate analysis. Multivariate analysis is often used to distill useful information from complex spectra.;We have designed a TOF-SIMS experiment that consists of various mixtures of three bio-molecules as a model for more complicated biomarker discovery. The peak picking algorithm is applied to the collected spectra. The algorithm detects peaks in the spectra repeatably and accurately. We also show that there are patterns in the spectra of pure biomolecules samples. Furthermore, we show it is possible to infer the concentration ratios in the mixture samples by checking the strength of the patterns.
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Yu, Zhonghua Walter. "Characterization of irreversible inhibition of proteases by mass spectroscopy." Scholarly Commons, 1995. https://scholarlycommons.pacific.edu/uop_etds/2805.
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Proteases are present in all living organisms and are involved in various biological processes. Inhibition of protease activities in disease-causing agents is one strategy for rational drug design. Characterization of the protease inhibition processes is essential for understanding the inhibition mechanisms and for developing efficient therapeutics. This work represents a major challenge in analytical biochemistry. In this study, a strategy based on mass spectrometry has been developed to characterize irreversible inhibition of proteases. Five proteases representing three of the four protease classes were irreversibly inhibited by various irreversible inhibitors, some of which are potential drug candidates. In all the cases, the stoichiometry of each of the protease/inhibitor complexes was determined by electrospray ionization mass spectrometry through measurement of the complex's molecular weight. The inhibited proteases were then enzymatically cleaved and the resulting peptides isolated for further characterization by high performance tandem mass spectrometry. Attention was focused on the determination of the site(s) of the modification and the reaction mechanisms involved. High energy collision induced dissociation mass spectra of each modified peptide provided information on the exact modification site(s) and the detailed chemical nature of the covalent complex. The serine protease trypsin, the cysteine protease cruzain, and the aspartic proteases, HIV-2 protease and SIV protease, were covalently modified only at one amino acid residue, while the aspartic protease, HIV-1 protease, was found to be modified at three sites by the haloperidol derivative compounds. In addition, mass spectrometry has been applied to characterize the plasma glycoprotein, biotinidase, and to obtain partial peptide sequences of a membrane-bound protein, UDP-GalNac:polypeptide N-acetylgalactosaminyl transferase, using a low picomole quantity of sample.
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Salter, Tara La Roche. "Metrology for ambient mass spectrometry." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28748/.
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Ambient mass spectrometry (AMS) is a new and versatile method for analysing a multitude of different sample types with the benefit of analysis at ambient pressure and the many other advantages that this entails. However, as these techniques are still in their infancy, metrological development of the techniques is essential. This is a critical step before AMS can be used reliably in the application areas in which it has shown great promise. The research in this thesis addresses the development of AMS sources, in particular plasma-assisted desorption-ionisation, PADI. Optimisation and characterisation is fundamental to understanding and developing the technique. Optimisation of PADI is addressed; this includes understanding the effects of different parameters to maximise signal intensities. The power, and temperature, of the plasma is shown to have a significant effect on the fragmentation observed in the mass spectra. This is an important result that is further explored with the use of thermal desorption to aid the analysis of low volatility molecules. The form of the analyte is also an important consideration for analysis by PADI; characteristic ions from powders are easily detected, whereas for thin film samples an analyte vapour pressure of greater than 10-4 Pa is needed. This result provides an indication of the limitations of PADI and what classes of analyte it will be successful at analysing. It is also shown that we can improve signal intensities using a heated sample stage allowing the analytes to be thermally desorbed before being ionised by the plasma. This is an important result for future work, where ambient plasma sources can be implemented as an ionisation source in conjunction with another mechanism, such as thermal or laser desorption, to generate gas-phase ions. A comparison of different ambient methods for personal care products shows the usefulness and also complementarities of PADI with desorption electrospray ionisation, DESI, one of the most established AMS techniques which utilises a different mechanism for desorption and ionisation. This also demonstrates the chemical information that can quickly be gained from these techniques, with minimal sample preparation. DESI is also compared to secondary ion mass spectrometry, SIMS. Vacuum-based techniques such as SIMS are much more established than ambient techniques; it is insightful to understand the advantages that each source can offer, for the analysis of different types of molecule as well as the mass spectral information that can be gained from SIMS and DESI.
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Botonjic, Edita. "Forensic and biological applications of vibrational spectroscopy /." View online ; access limited to URI, 2004. http://wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3160028.
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Johnston-Theasby, Faye. "Spectroscopy of N-Z nuclei in the mass 80 region." Thesis, University of York, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547359.
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Moody, Christopher M. "Black writing ink analysis by direct infusion electrospray mass spectroscopy." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4537.
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An optimized method of extraction, an instrumental analysis method and data analysis was proposed for black writing inks based on direct infusion electrospray-mass spectrometry (ESI-MS). The sampling and analysis method is both minimally destructive and able to assess differences in inks from a reference collection of thirty ballpoint, gel, and rollerball inks. The methanol extracts of ink on paper samples were analyzed with three direct infusion (ESI-MS) methods. Each method varied scan voltage negative and positive, ESI fragmentor applied voltage (+120V, +0V, and -120V), and mobile phase additive. Direct infusion ESI-MS analysis, followed by pair-wise comparisons of the observed ion data in binary form allowed inks to be distinguished from each other. The photobleaching of the dye Basic Violet 3 (BV3) in ink-on-paper samples was examined to determine the use of degradation products as a marker of the age of the writing sample. The extent of photobleaching of BV3 was determined using several illumination sources. Pair-wise comparison of observed ion data was able to distinguish 29 of 30 ink samples using the combined three instrumental methods. Out of 435 pair-wise comparisons 429 pairs could be discriminated from each other using the combined three methods. This is a 98.6% discrimination with the combined analysis scheme.ID: 029051039; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2010.; Includes bibliographical references (p. 80-82).
M.S.
Masters
Department of Chemistry
Sciences
Forensic Science
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Crosland, S. "Qualitative and quantitative aspects of fast atom bombardment mass spectroscopy." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383683.
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Leeson, Alistair M. "Time-of-flight secondary ion mass spectroscopy of polymer surfaces." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268294.
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Naylor, S. "Applications and mechanistic aspects of fast atom bombardment mass spectroscopy." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234018.
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Steele, Iain A. "Photometry and spectroscopy of low mass stars and brown dwarfs." Thesis, University of Leicester, 1994. http://hdl.handle.net/2381/35798.
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This thesis describes an investigation of the faintest known proper motion members of the Pleiades star cluster. The primary aim of the work is an attempt to determine whether the lowest mass members of the cluster are brown dwarfs. A brief introduction outlines the fundamental properties of brown dwarfs and discusses the relation of research in this area to other branches of astronomy. The second chapter describes the basic principles of astronomical photometry and spectroscopy, the instruments used and the methods of data reduction. Chapter three gives a review of the current theory and observations of brown dwarfs. The results are presented in chapters four, five and six. RIJHK photometry for a sample of 62 objects is presented. The 1,1 - K diagram is shown to be a good discriminant of binary status for low mass cluster objects and using this diagram two single brown dwarf candidates and seven potential brown dwarf containing binaries are identified. FOS optical spectroscopy of 31 objects is used in an investigation of temperature indicators for cool stars. In addition gravity sensitive features indicate that the surface gravity of the Pleiades objects is lower than equivalent main sequence objects. Also discussed are the chromospheric and coronal activity of cluster members, and evidence is presented showing a turnover in both at ~ 0.3M⊕, where the objects become fully convective. CGS4 1-2.5 micron spectra are used in a futher investigation of methods of determining effective temperature and in searching for evidence of low mass companions. One object shows evidence for a low mass companion of ~ 0.035M⊕. Chapter seven discusses the evidence from these results that the faintest members observed are brown dwarfs and evidence from other workers that they are not. This chapter also gives suggestions for future work. Appendices compile the theoretical models and data used in the project.
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Sequeira, Anna J. "Analysis of wood pulp extracts utilizing gas chromatography-mass spectroscopy." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39964.
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Pothireddy, Jayanth. "Mass spectroscopy applied to gas leak detection and fuel ionization." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000880.
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Marcantonio, Laurence Mark. "Unquenched lattice upsilon spectroscopy." Thesis, University of Glasgow, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341965.
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Rodrigues, Kevin Liu 1990. "Espectroscopia de capacitância de nanoagregados metálicos selecionados em massa = Capacitance spectroscopy of mass selected metal nanoaggregates." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/276934.
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Orientador: Varlei RodriguesDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-08-28T03:02:40Z (GMT). No. of bitstreams: 1 Rodrigues_KevinLiu_M.pdf: 15717954 bytes, checksum: 0231043634d153e2ddc45e00a8630aaa (MD5) Previous issue date: 2015
Resumo: O estudo de nanopartículas é desafiador devido à complexidade destes sistemas, que estão na interface entre o pequeno e o grande. A física dos sólidos deixa de valer em muitas das partículas menores devido ao alto grau de confinamento, e a fração de átomos de superfície para átomos no núcleo. Devido à natureza pequena dos \textit{clusters}, as medidas realizadas nestes sistemas são medidas de alto grau de precisão. Com o objetivo de caracterizar feixes de fontes de agregados de maneira rápida e acessível, um circuito capacímetro é utilizado para medir a influência da deposição de nanopartículas na região dielétrica de um capacitor, uma proposta em aberto na área de nanopartículas. Como essa medida captura a contribuição de inúmeros agregados diferentes, todos depositados na região dielétrica do capacitor, um filtro seletor de massas pode ser utilizado para estreitar a largura da distribuição de tamanhos e obter a influência causada por esse tamanho específico apenas. Neste trabalho será apresentado o projeto para a implementação de um filtro com esse propósito, original de Issendorf e Palmer, cujo princípio de operação é o tempo de voo das partículas, e tem resolução esperada de uma parte em quarenta. Medidas de capacitância também foram realizadas na tentativa de caracterizar a variação da capacitância em função da quantidade de material depositado, com resultados promissores, mas que requerem um maior refinamento das medidas. Os nanoagregados foram produzidos depositados e analisados no Grupo de Física de Nanossistemas e Materiais Nanoestruturados (GFNMN) da física da Unicamp
Abstract: The study of nanoparticles is a challenging one because of the complexity of these systems, which lie on the interface between the small and the big. By that it is meant that many crystals and solids approximations cease to work, and confinement effects begin to appear, as well as surface phenomena which gain strength as surface to volume atoms increase. Due to the small particle sizes, measurements become increasingly difficult, requiring higher and higher precision techniques. With the objective of quickly characterizing beams produced by nanoaggregates sources, a capacitance measuring circuit was created with the intent of measuring the influence of the aggregates on the dielectric constant of the medium between the electrodes, a technique which has not been applied to cluster beams yet. In combination with the capacitance measurements, a mass selecting device was built in order to make the capacitance measurements reflect only a narrow mass distribution, allowing the study of properties of a single cluster size provided they are small enough. In this study will be discussed the project for such a mass filter, original by Issendorf and Palmer, and its implementation on a cluster source. Its principle of operation is the time of flight mass spectrometry, and its projected resolution of about one part in forty. Capacitance measurements were also performed to try and characterize the capacitance change as a function of the density of deposited material. The results were promissing but require further refinement for a strong correlation. All the particle beams were produced at the cluster source operating at the GFNMN group at the department of applied physics at IFGW Unicamp
Mestrado
Física
Mestre em Física
2011/15018-7
FAPESP
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Asad, A. H., L. Morandeau, S. Chan, C. M. Jeffery, S. V. Smith, and R. I. Price. "Quality assurance of 61Cu using ICP mass spectroscopy and metal complexation." Helmholtz-Zentrum Dresden - Rossendorf, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-166486.
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Introduction
61Cu (T1/2 = 3.33 hr, Eβ= 1.22 MeV, 61.4 %) is an attractive isotope for positron emission tomography (PET) radiopharmaceutical agents such as ATSM and PTSM. Various separation processes have been reported for the production of 61Cu on a medium cyclotron using 13–22 MeV protons on natural and enriched 64Zn target materials [1,2].
This work, investigates production of 61Cu using both natural and enriched 64Zn targets and its separation. Three types of resins were used to assess for their efficiency and speed to separate the desired 61Cu from the 66,67,68Ga and 64Zn and for the recycling of 64Zn target material. The effective specific activity of purified 61Cu, was determined by ICP-MS and its titration with various polyaza and polycarboxylate complexing ligands.
Material and Methods
1. Production and Separation
Targets were irradiated by proton beam of IBA cyclotron 18/18MeV via the 64Zn(p,α) 61Cu and natZn(p,x) 61Cu reactions using an enriched 64Zn foil(15×15×0.05mm, ~50 mg) and natural foil (diameter 25 mm, 0.05 mm,~ 60 mg). Thirty minute irradiations were conducted with incident proton energies between 11.7–12.0 MeV and beam currents of 20 and 40 µA. Irradiated Zn targets were dissolved in 8M HCl at 150 oC then evaporated to dryness. Trace water to the resultant residue (twice) and resultant solutions evaporated to dryness. The residue was re-dissolved in 2ml of 0.01M HCl before loading onto a Cu-resin column (FIG. 1) Zn and Ga isotopes were collectively eluted using 30 ml of 0.01M HCl. The Cu was then removed using 1.5 ml of 8M HCl and passed directly onto a cation exchange followed by an anion exchange column. An additional 3 ml of 8M HCl was used to rinse the cation exchange column and ensure quantitatively removal of Cu (II) ions. The Cu was finally eluted from the anion exchange column using 3 ml of 2M HCl. The Cu solution was heated up at 150 oC until evaporated to dryness and 61Cu final product dissolved in 400–800 μL of 0.01M HCl.
2. Specific activity of 61Cu
The specific activity (GBq/µmol) of the purified 61Cu was determined by ICP-MS and compared with that determined using dota, nota and di-amsar complexing ligands.
For each 61Cu production run aliquot of final solution (100 µL) was left to decay before dilut-ing to 10 mL with 10% HNO3. Decayed samples were sent to ChemCentre (Curtin University) for ICP-MS analysis. Each sample was analysed for Cu, Al, Ca, Co, Fe, Ga, Ni, Si, and Zn, which are known to compete with Cu2+ for ligand complexation.
Effective specific activity of the 61Cu was deter-mined by titrating various known concentration of ligands with 61Cu solution. The method is detailed in the literature [3]. Briefly, varying concentrations of each ligand was prepared in 0.1M sodium acetate buffer pH 6.5 to a total volume 20 µL. Fixed concentration of diluted 61Cu (0.01M HCl) in 10 µL was added to each ligand solution. The mixtures were vortexed then left to incubate at the room temperature for 30 mins. Two uL aliquots were withdrawn (in triplicate) from each reaction mixture and spot-ted on ITLC –SA. [Mobile phase: 0.1M NaCl: 0.1M EDTA (9:1) for Cu2+ and diamsar mixtures: Rf <0.2 Cu-diamsar; Rf > 0.8 free Cu2+ and 0.1M sodium acetate pH 4.5: H2O: MeOH: ammonium hydroxide (20:18:2:1 v/v) for Cu2+ dota and nota mixtures: Rf >0.8 Cu-dota and Cu-nota Rf < 0.2 free Cu2+]. Complexation of the 61Cu with each ligand was complete within 30 mins at room temperature. Concentration of Cu2+ was deter-mined from the 50% labelling efficiency.
Results and Conclusion
1. Production and Separation
The radioisotopes production from natZn target must be minimized by the optimum proton energy to reduce a radiation dose in the final product. The excitation functions of 66,67,68Ga ,65Zn and 61Cu are shown in FIG. 2. Proton beam energy of 11.7 MeV was used for both Zn targets to minimise the production of Ga isotopes and prevent formation of 65Zn. For the enriched 64Zn target (99.30%) higher proton energy could be used for the production of 61Cu allowing for increased yields and reduce radio contaminants. Previously, we used anion and cation exchange resin as described in the literature to separate the 61Cu [1]. Unfortunately the literature method was too long (up to 3 hours) and requiring high concentration of HCl and long evaporation times compromising achievable yields [4]. Thieme S. et al., 2013 [2] reported the successful use of Cu-resin for the separation of Cu radioisotopes and it was of interest to the current work to test this material for the separation of 61Cu in our hands.
A cation, anion exchange and Cu-resin were combined into closed system to separate the 61Cu within 30 mins (FIG. 1). The system is designed to contain the transfer of solutions be-tween each column using simple plunger to force solution through and between each column. This system afforded an easy, reliable and fast separation of 61Cu that could be completed within 30 min.
2. Specific activity
The specific activity of 61Cu was determined using ICP-MS and by titration with three ligands is summarized in TABLE 1. The ICP-MS data show values ranging from 9.2 to 32.4 GBq/μmol for 8 production runs. Specific activity determine using nota and dota were in all cases lower than the ICP MS data indicating some interference from the other metal ion contaminates such as Fe(ii/Iii), Ni (II), Ca (II), Zn (II), Ga (III). The specific activity determine using diamsar, which is known to be highly selective for Cu(II) (and Zn(II) and Fe(III)) in the presence of alkali and alkaline earth ions gave values significantly higher effective specific activity than that obtained using ICP MS. Variations in values can be explained by presence of contaminating metal ions.
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Dale, Vanessa Cordelia Meriel. "The study of cyanobacterial toxins by means of tandem mass spectroscopy." Thesis, University of Warwick, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282458.
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Simpson, Matthew James. "Ion-molecule reaction mass spectrometry and vacuum-ultraviolet negative photoion spectroscopy." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/1056/.
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Two separate experimental techniques have been used to investigate the fundamental properties of small polyatomic molecules in the gas phase. Selected ion flow tube mass spectrometry has been used to study the reactions of cations and anions with ethene, monofluoroethene, 1,1-difluoroethene, trifluoroethene and tetrafluoroethene. Calculated collisional reaction rate coefficients are compared to those measured by the experiment. The product ions from these reactions have been detected and their branching ratios measured. Many of these results have been explained using arrow-pushing mechanisms. Using tunable vacuum-ultraviolet radiation from a synchrotron, negative ions have been detected following photoexcitation of 24 gaseous molecules. The majority of the molecules studied are halogen-substituted methanes. Product anions resulting from unimolecular ion-pair dissociation reactions were detected, and their ion yields recorded in the range 8-35 eV. Absolute cross sections for ion-pair formation and resulting quantum yields are calculated. This vast collection of data is summarised and ion-pair formation from polyatomic molecules is reviewed.
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Krauss, Miriam Ilana. "X-ray spectroscopy of neutron star low-mass X-ray binaries." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/45408.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2007.Includes bibliographical references (p. 133-150).
In this thesis, I present work spanning a variety of topics relating to neutron star lowmass X-ray binaries (LMXBs) and utilize spectral information from X-ray observations to further our understanding of these sources. First, I give an overview of important X- ray astrophysics relevant to the work I present in subsequent chapters, as well as information about the X-ray observatories from which I obtained my data. In the next three chapters, I consider spectra-both high- and low-resolution--of accretion-powered millisecond X-ray pulsars, a unique and relatively new class of objects. In addition to analysis of the pulsar XTE J1814-338, I compare a broader sample of pulsars with a sample of atoll sources in order to better understand why the latter class do not contain persistently pulsating neutron stars. In particular, I test the hypothesis that pulsations in the atoll sources are suppressed by a high-optical- depth scattering region. Using X-ray color-color diagrams to define a selection criterion based on spectral state, I analyze Rossi X-ray Timing Explorer (RXTE) spectra from all the sources, and use a Comptonization model to obtain measurements of their optical depths. I then discuss efforts to spatially resolve X-ray jets from the accretion-powered millisecond pulsar SAX J1808.4-3658 and the Z source XTE J1701-462. Each was observed by the Chandra X-ray Observatory to produce a high-spatial-resolution image. This work was motivated in part by my analysis of XTE J1814-338, which found an apparent excess of infrared flux which could be attributed to jet emission. Next, I discuss the measured temperatures of thermonuclear X-ray bursts. The detection of line features in these bursts, and hence from the surfaces of neutron stars, has been an important goal for high-resolution X-ray spectroscopy. A measurement of the wavelengths of identified line features would yield a measurement of the neutron star's gravitational redshift, which would help constrain current models for the neutron star equation of state.
(cont.) Although such a measurement has been made for one source, other searches have not been able to repeat this measurement. I consider the effects of burst temperature on the formation of discrete spectral features, using a large sample of bursts observed by the RXTE PCA. Finally, I present analysis of high-resolution Chandra HETG spectra of a sample of Galactic LMXBs. High-resolution spectra are able to resolve line features, such as the prominent Ne and O emission lines in the ultracompact X-ray binary 4U 1626-67. They also allow for more precise measurements of photoelectric absorption edges, which can otherwise hinder the determination of continuum spectral components, particularly in the lower-energy spectral regions.
by Miriam Ilana Krauss.
Ph.D.
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Majola, Siyabonga Ntokozo Thandoluhle. "Exploring the spectroscopy of vibrational levels in the 160 mass region." Doctoral thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20815.
Full textAbstract:
Vibrational levels are well known in atomic nuclei but despite many decades of research, some of their properties still remain elusive. In particular, low-lying rotational bands based on the first excited 0+ state, which are traditionally understood as β vibrational bands nevertheless show properties at odds with this interpretation, more especially in the transitional rare earth region with N~ 90 [Gar01]. An alternative is that they can be better be described as a "second vacuum", or coexisting minimum in the pairing degree of freedom [Sch11a]. In order to produce a complete and definitive microscopic picture of the so-called β and γ bands, an extensive systematic review is performed for nuclides in the 160 mass region, between N = 88 and 92 and Sm to Yb. The data are explained using a five dimensional collective Hamiltonian for quadrupole rotational and vibrational degrees of freedom [Li09, Nik09]. A good qualitative agreement is obtained between measured energies and electromagnetic transition rates across the entire A ~ 160 mass region. The implication of these findings on the interpretation the first excited 0+ states is there from discussed. In this study, the γ-ray spectroscopy of 156Dy and 157Dy are also revised. Three experiments with different reactions to produce 156Dy have been analyzed. The data were acquired using the 155Gd (α, 3n) 156Dy and 148Nd (12C, 4n) 156Dy and 124Sn (36S, 4n) 156Dy reactions at beam energies of 25, 65 and 165 MeV, respectively. The 155Gd (α, 3n) 156Dy experiment was performed with aid of the JUROGAM II array. The experiments that used the 148Nd (12C, 4n) 156Dy and 124Sn (36S, 4n) reactions were both conducted using the GAMMASPHERE array. In total, the current work reports the observation of about 30 bands in 156Dy. The spins and parities for the majority of new rotational structures have been successfully assigned using the Directional Correlation from Oriented States (DCO ratios) and polarization anisotropy (Ap). In order to meaningfully describe the quantum behavior of the newly established structures, the Nilsson and Cranked Shell Models have been used. The results also test the latest and most sophisticated quantum theories of nuclear structure and also point to inadequacies of these models, where they exist. Amongst important spectroscopic features, is the identification of the γ wobbling candidate, which implies in some way that 156Dy is γ deformed. Extensions have been made on the γ bands and they are now observed to spins 31+ and 32+, which marks the highest spin to be ever observed for both the odd and even spin members of the γ bands in any nucleus. The current study also reports the first candidate for the aligned γ bands based on the two-quasiparticle configurations (S-band). This is the first time "γ bands" have been identified on both the ground state band (continuation) and on the yrast aligned S-band. Finally, an odd spin negative parity sequence, namely band 9, has been identified as a candidate of the K = 1- octupole excitation. [Please note: the full text of the thesis is deferred until January 2018]
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Gregory, Paul David. "Mass spectrometry and matrix isolation of high temperature molecules." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261012.
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Griffin, Jeffrey Cliff. "Decay of mass-separated [superscript]195Bi to levels in [superscript]195Pb : collinear laser spectroscopy on mass-separated neutron-deficient lead isotopes." Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/27319.
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Nwogu, Vincent Ikechukwu. "Electrothermal vaporization sample introduction for inductively coupled plasma atomic emission and inductively coupled plasma mass spectrometry." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/30762.
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Tutcher, B. "Time-of-flight mass-resolved multiphoton ionisation spectroscopy of simple molecules and radicals." Thesis, University of Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233113.
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Karahan, Mehmet Cem. "Laser-assisted secondary ion mass spectroscopy and its applications in practical surface analysis." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/karahan/KarahanM0805.pdf.
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Canty, James Ignatius. "Investigating the properties of brown dwarfs using intermediate-resolution spectroscopy." Thesis, University of Hertfordshire, 2015. http://hdl.handle.net/2299/15194.
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This thesis is an investigation into some properties of brown dwarfs using medium-resolution spectroscopy. In the first part of the thesis, I address the issue of parameter degeneracy in brown dwarfs. In the course of my analysis, I derive a gravity-sensitive spectral index which can be used, statistically at least, to differentiate populations of young objects from field dwarfs. The index is also capable of finding the difference between a population of ~1 Myr objects and a population of ~10 Myr objects and may be used to separate low-mass members from foreground and background objects in young clusters and associations. The second part of my thesis is an investigation into the major opacity sources in the atmospheres of late T dwarfs. I look particularly at CH4 and NH3 absorption features in the near-infrared spectra of these objects. In my analysis, I identify new absorption features produced by these molecules. I also correct features which had previously been wrongly identified. This has been made possible by the use of high quality data, together with a new CH4 synthetic line list, which is more complete at these temperatures than any previously available list.
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Rutter, Abigail Victoria. "Improving the management of lung cancer using mass spectrometry and spectroscopy techniques." Thesis, Keele University, 2016. http://eprints.keele.ac.uk/2388/.
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Lung cancer is a worldwide health problem associated with poor prognosis. The survival at 5 years remains between 5% and 15% in spite of the development of new drugs. One of the main reasons for this is the disease being diagnosed in late stages when curative treatments might not be available. Therefore, some of the most important factors within improving prognosis are both refining diagnostic techniques for early detection, and better assessing tumour response to treatment. Here lies a need for novel diagnostic tools for lung cancer. Spectroscopic and spectrometric analysis of the molecular underpinnings of the disease may provide biochemical signatures for use in diagnostics. Selected Ion Flow Tube – Mass Spectrometry (SIFT-MS) and Fourier Transform Infrared (FTIR) Spectroscopy may provide the gold standard of diagnostic assessment that is needed. Given both techniques previous contributions and technological advancements, their clinical requirements are being increasingly met. This is leading towards the opportunity for the study of lung cancer to benefit from the rapid, non-destructive and sensitive qualities they have to offer. In this thesis, both techniques have been used with the aim of improving the diagnosis and management of lung cancer.
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Braun, Christian [Verfasser]. "Time-resolved photoelectron spectroscopy of mass-selected metal-water clusters / Christian Braun." Konstanz : Bibliothek der Universität Konstanz, 2012. http://d-nb.info/1026847141/34.
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Pan, Changkang. "Characterization of solvent-plasma interactions for inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/30536.
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McMahon, Callie Griggs. "Muscle Strength and Body Cell Mass in Postmenopausal Women." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/42296.
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It has been observed that the normal process of aging is associated with a decline in muscle strength and mass. It has also been observed that total body potassium and intracellular water (ICW) decrease with age, reflecting a loss of body cell mass (BCM), 60% of which is the skeletal muscle. It is generally accepted that traditional high-intensity strength training (ST) regimens can not only attenuate, but in some cases, reverse some of these aging-related changes. Periodization, a nontraditional approach to strength training, has been demonstrated to stimulate more rapid increases in muscle strength than traditional approaches in young adults; however, it has not been comprehensively evaluated in postmenopausal women. Investigators have consistently reported an increase in muscle strength in older adults undergoing both short- and long-term traditional ST programs. It is fairly well accepted that early increases in muscle strength are attributable to neurologic adaptations. There has been less consistency in the literature regarding the timing and nature of changes in muscle quality and mass with ST. Although several investigators have reported increased muscle protein synthesis rates as early as 2 weeks after ST initiation in older adults, the majority of published reports support the notion that significant NET gains in intracellular protein, and thus, gains in muscle mass/volume/hypertrophy do not occur before 9-10 weeks. Changes in intracellular water, which would be expected to occur with changes in intracellular protein, have not been studied during short-term ST interventions in older adults. Bioimpedance spectroscopy (BIS) has been validated as a field technique to accurately measure ICW (and BCM) changes in HIV infected individuals. The primary aim of the current study was to determine if muscle strength would increase in postmenopausal women undergoing a novel (periodized) ST intervention of 10 weeks duration. A secondary aim was to determine if BIS would detect a change in ICW in the study subjects from baseline to study conclusion.
Study participants were eleven, healthy postmenopausal women between the ages of 60 and 74 (mean age: 65 ± 4.4 y) who had not engaged in ST in the six months preceding the study. ICW and muscle strength were assessed at baseline and at study conclusion. The ST program was conducted twice a week for 10 weeks at the Senior Center in Blacksburg, VA. Participants performed seven different exercises incorporating upper body and lower body muscle groups. The women performed one set of 8-12 repetitions at an intensity of 80% of one repetition maximum (1 RM) the first week, progressing to 2 sets of 8-12 repetitions at the same intensity during the second week. The remaining weeks consisted of three sets of 8-12 repetitions, performed at an intensity of 80%, 75%, and 70% of their current 1 RM, respectively. One RM was reassessed every other week. The major result from this study was that muscle strength of all trained muscle groups increased in postmenopausal women undergoing 10 weeks of pyramid ST (P<0.05). In addition, the pyramid ST protocol utilized in this study was well-tolerated and resulted in no injuries in any of the older women in the study, indicating that this approach may be used safely in this population. Mean ICW measured by the field method BIS did not change over the course of the study. This result was consistent with other published data reporting no changes in lean body mass or muscle volume/area by more sophisticated techniques.Master of Science
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Towers, Brittany N. "Rapid Quality Assessment of Corn-Based products by Infrared Spectroscopy and Selected Ion Flow Tube Mass Spectroscopy with Multivariate Analysis." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366368685.
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Carrott, Michael J. "Supercritical fluid chromatography and spectroscopic detection." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388419.
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Li, Ling. "Catalytic methane reformation and aromatization reaction studies via cavity ringdown spectroscopy and time of flight mass spectrometry." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39707404.
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Li, Ling, and 李凌. "Catalytic methane reformation and aromatization reaction studies via cavity ringdown spectroscopy and time of flight mass spectrometry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39707404.
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Nelms, Nicholas. "A new determination of the charged pion mass and muon neutrino mass upper limit from exotic atom X-ray spectroscopy." Thesis, University of Leicester, 2002. http://hdl.handle.net/2381/30661.
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This thesis describes an experiment that has made a new determination of the charged pion mass and from which a new upper limit of the muon neutrino mass has been calculated. The experimental approach uses a high-intensity negative pion beam injected into a cyclotron trap and stopped inside a nitrogen/oxygen mix gas-filled target cell where highly excited pionic and muonic atoms are formed. The energy of photons emitted during de-excitation is directly proportional to the reduced mass of the system, from which the mass of the orbiting particle can be determined. X-ray spectra from pionic nitrogen and muonic oxygen are measured using a high-resolution Bragg crystal spectrometer arranged in Johann geometry. A new large area detector comprising six, high quantum efficiency charge coupled devices is positioned at the focus to measure the reflections from the spectrometer. By using muonic oxygen X-rays as calibration for the pionic nitrogen line the negative pion mass has been determined as 139.57176 0.000259 MeV/c2, a precision of 1.85 ppm. Although more precise, this value is approximately 11 ppm higher than the current world average. Consequently, the muon neutrino mass upper limit has been calculated as 0.33 MeV/c2 (90% confidence level) which offers no new information over the current value of 0.17 MeV/c2. Investigations are underway to determine the validity of the 11 ppm discrepancy.
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Aslan, Evren. "Characterization Of Conducting Polymers Of Ester Linkage Containing Thiophene Derivatives Via Mass Spectroscopy." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12605704/index.pdf.
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ABSTRACT
CHARACTERIZATION OF CONDUCTING POLYMERS OF ESTER LINKAGE CONTAINING THIOPHENE DERIVATIVES
VIA MASS SPECTROSCOPY
Aslan, Evren
M.Sc., Department of Chemistry
Supervisor: Prof. Dr. Levent Toppare
Co-Supervisor: Prof.Dr. Jale Hacaloglu
December 2004, 86 pages
In order to investigate the thermal and structural characteristics of terepthalic acid bis-(2-thiophen-3-yl-ethyl)ester (TATE), decanedioic acid bis-(2-thiophen-3-yl- ethyl) ester (DATE) and octanoic acid 2-thiophen-3-yl-ethyl ester (OTE), their corresponding homopolymers, copolymers with thiophene and polythiophene, pyrolysis mass spectrometry technique was utilized. The results were discussed in detail considering the effects of spacer group in between ester linkages. Thermal Gravimetry Analysis was used to investigate the weight loss for polymers and monomers. Conductivities of samples were measured by four-probe technique.
It was found that when the ester linkages contain hydrocarbon chains, the growth of polymer occurred through both 2 and 5 positions. On the other hand, when the ester linkages contain more rigid groups such as phenyl, steric hindrance inhibited the growth of the polymer through 2- position and polymerization proceeded via coupling of thiophene moieties mainly at 5-position yielding a polymer with lower conductivity. Though the structure of P(OTE) is inherently different than P(DATE) and P(TATE) extent of network structure is also quite low for this polymer compared to PTh.
Similar thermal characterizations were recorded indicating that thermal units were not significantly affected by the presence of TATE, DATE or OTE for all copolymer samples.
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Stanja, Juliane. "Synergy of decay spectroscopy and mass spectrometry for the study of exotic nuclides." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-113289.
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With only two ingredients, atomic nuclei exhibit a rich structure depending on the ordering of the different proton- and neutron-occupied states. This ordering can give rise to excited states with exceptionally long half-lives, also known as isomers, especially near shell closures. On-line mass spectrometry can often be compromised by the existence of such states that may even be produced in higher proportion than the ground state.
This thesis presents the first results obtained from a nuclear spectroscopy setup coupled with the high-resolution Penning-trap mass spectrometer ISOLTRAP, at CERN’s radioactive ion beam facility ISOLDE. The isomerism in the neutron-deficient thallium isotopes was investigated. The data on 184,190,193−195 Tl allow an improvement of existing mass values as well as a mass-spin-state assignment in 190,193,194 Tl. Due to the presence of the ground and isomeric state for 194 Tl the excitation energy of the latter was determined for the first time experimentally. Systematic trends in the vicinity of the Z = 82 shell closure have been discussed.