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Dissertations / Theses on the topic 'NMR spectrometers'

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Published: 4 June 2021
Last updated: 19 February 2022

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1

Chaudhry, Humayun Iqbal. "An evaluation of the performance and mechanistic action of the costabiliser N-phenyl-3-acetyl pyrrolidine-2,4-dione and its derivatives in poly(vinyl chloride)." Thesis, Manchester Metropolitan University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311051.

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2

CUNHA, TATIANA F. da. "Aplicação do poli(epsilon-caprolactona) com estrutura estrelada para obtenção de microesferas biorreabsorvíveis." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10544.

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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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3

Ariando, David Joseph. "A Portable Low-Cost NMR Spectrometer." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1515170982121573.

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4

Digby, Megan Elizabeth. "Broadband DC SQUID NMR spectrometry on metals." Thesis, Royal Holloway, University of London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322702.

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This Thesis describes the development of a broadband pulsed NMR spectrometer, based on a sensitive DC SQUID amplifier with wideband electronics, to observe directly the free precession of nuclear spins in bulk metallic samples (with broad NMR linewidths) at Larmor frequencies cß/2 ,r below 1 MHz. The sample is located inside a pickup coil, which forms a superconducting flux transformer with the input coil of the SQUID. The SQUID amplifier operates in a flux-locked-loop (FLL), hence it is sensitive to signals from DC up to the bandwidth of the FLL electronics. A modified commercial DC SQUID amplifier, with modulated feedback electronics, observed NMR signals from bulk platinum samples (T2 - 1.1 ms), at 1.5 K. The SQUID amplifier had a 50 kHz bandwidth, a dead-time - 50 μs, and a coupled energy sensitivity cc - 500h. The measurements showed that it is important to minimise the time-constant of eddy current decay in the sample, which scales with r2, as expected, where r is the sample dimension. A DC SQUID amplifier with additional positive feedback and wideband electronics configured using the direct offset integration technique, observed NMR signals from a bulk aluminium sample (T2 - 30 μs) at 20 mK. This SQUID amplifier had a 7.5 MHz bandwidth, the dead-time was 55 μs for small transmitter pulses and e,; - 600h. The use of a strongly coupled input coil with the SQUID necessitated damping across the coil to smooth out the SQUID flux-voltage characteristicThe NMR measurements showed that eddy current decay is less important if the NMR signal size is enhanced by cooling the sample. Measurements also confirmed that the NMR signal from bulk metal is proportional to 4c0, and that a reasonable estimate of the signal size is made by assuming the signal is due to spins within half the skin-depth of the surface
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5

Hughes, Leslie Peter. "Maximum entropy methods applied to NMR and mass spectrometry." Thesis, Durham University, 2001. http://etheses.dur.ac.uk/3785/.

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Maximum Entropy data processing techniques have been widely available for use by NMR spectroscopisis and mass spectrometrisls since they were first reported as a tool for enhancing damaged images. However, the techniques have been met with a certain amount of scepticism amongst the spectroscopic community; not least their apparent ability to get something for nothing. The aim of the work presented in this thesis is to demonstrate that if these techniques are used carefully and in appropriate situations a great deal of information can be extracted from both NMR and mass spectra. This has been achieved by using the Memsys5 and Massive Inference algorithms to process a range of NMR and mass spectra which suffer from some of the problems which are commonly encountered in spectroscopy, i.e. poor resolution, poor sensitivity, how to process spectra with a wide range of peak widths. The theory underlying the two algorithms is described simply and the techniques for selecting appropriate point spread functions are outlined. Experimental rather than simulated spectra are processed throughout. Throughout this work the Maximum Entropy results are freated with scepticism. A pragmatic approach is employed to demonstrate that the results are valid. It is concluded that the Maximum Entropy methods do have their place amongst the many other data processing strategies used by spectroscopists. If used correctly and in appropriate situations the results can be worth the investment in time needed to obtain a satisfactory result.
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6

McGill, Colin Adam. "Studies of low-field nuclear magnetic resonance and Raman spectrometries for process analytical chemistry." Thesis, University of Strathclyde, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248282.

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7

Barlow, G. K. "Development and application of some techniques for proton and sodium NMR." Thesis, University of York, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383846.

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8

Gädke, Achim, Markus Rosenstihl, Christopher Schmitt, Holger Stork, and Nikolaus Nestle. "DAMARIS – a flexible and open software platform for NMR spectrometer control." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-194317.

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Home-built NMR spectrometers with self-written control software have a long tradition in porous media research. Advantages of such spectrometers are not just lower costs but also more flexibility in developing new experiments (while commercial NMR systems are typically optimized for standard applications such as spectroscopy, imaging or quality control applications). Increasing complexity of computer operating systems, higher expectations with respect to user-friendliness and graphical user interfaces as well as increasing complexity of the NMR experiments themselves have made spectrometer control software development a more complex task than it used to be some years ago. Like that, it becomes more and more complicated for an individual lab to maintain and develop an infrastructure of purely homebuilt NMR systems and software. Possible ways out are: ● commercial NMR hardware with full-blown proprietary software or ● semistandardized home-built equipment and common open-source software environment for spectrometer control. Our present activities in Darmstadt aim at providing a nucleus for the second option: DArmstadt MAgnetic Resonance Instrument Software (DAMARIS) [1]. Based on an ordinary PC, pulse control cards and ADC cards, we have developed an NMR spectrometer control platform that comes at a price tag of about 8000 Euro. The present functionalities of DAMARIS are mainly focused on TD-NMR: the software was successfully used in single-sided NMR [2], pulsed and static field gradient NMR diffusometry [3]. Further work with respect to multipulse/multitriggering experiments in the time domain [4] and solid state NMR spectroscopy multipulse experiments are under development.
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9

Pagnano, Marco Aurelio de Oliveira. "Automação de um espectrômetro por ressonância magnética nuclear pulsada." Universidade de São Paulo, 1993. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-19082014-101639/.

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Este trabalho consistiu na automação do espectrômetro de Ressonância Magnética Nuclear Pulsada existente no laboratório dos professores José Pedro Donoso e Claudio José Magon. Foram efetuados circuitos adicionais e melhorias no equipamento que eles possuíam, à nível de hardware e software. Foram construídas e programadas interfaces paralelas que ligam o microcomputador a um gerador de pulsos, fabricado pela Tecmag Inc., e a um digitalizador rápido (10 ns) Nicolet 430. O programador de pulsos pode acionar independentemente 75 linhas durante o intervalo de tempo subdividido em 2048 eventos, também independente. O software desenvolvido permite a programação de todas as linhas e eventos de forma eficiente e prática. Foi todo escrito em linguagem C, é modular, portátil, e permite a geração de seqüências de pulsos sofisticadas e também o controle da aquisição e transferência de dados
This work describes the Project developped to automatize the pulsed nuclear magnetic resonance spectrometer housed in the laboratory of the professors José Pedro Donoso e Cláudio José Magon. To satisfy our needs we have improved their old equipment, at the level of hardware and software. Were built and programmed the parallel interface between the microcomputer and a pulse programmer made by Tecmag Inc. and with a fast digitizer (10 ns) Nicolet 430. The pulse programmer can control 75 independent output channels during 2048 time intervals. The software we developped allow us to control the whole pulse sequence on a very efficient and practical way. It was written in C-language, and provides the timing signals necessary to generate sofisticated pulse seqüencies, the data acquisition and data transfer to the host computer
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10

Gipson, Geoffrey T. Sokhansanj Bahrad. "Discovery Of discriminative LC-MS and 1H NMR metabolomics markers /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2766.

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11

Gouilleux, Boris. "Gradient-based methodson a benchtop spectrometer : new perspectives for low-field NMR spectroscopy." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4036/document.

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La RMN à haut champ, basée sur des aimants supraconducteurs, est caractérisée par une instrumentation onéreuse et encombrante qui limite son utilisation dans les environnements de production. Le récent renouveau des aimants permanents a engendré des spectromètres RMN de paillasse qui permettent la réalisation d’expériences RMN directement sous la hotte du chimiste. L’objectif de cette thèse est d’améliorer la performance analytique de ces nouveaux spectromètres à bas champ. Dans cette optique, nous avons implémenté pour la première fois la RMN 2D Ultrarapide (UF) ainsi que des méthodes modernes de suppression du signal du solvant sur un spectromètre de paillasse opérant à 43 MHz équipé d’une bobine de gradient de champ magnétique. Suite à plusieurs optimisations, la RMN 2D UF à bas champ délivre des spectres 2D en un temps fortement réduit de qualité tout à fait intéressante. En parallèle, le développement des méthodes de suppressions permet dorénavant d’appréhender l’utilisation de solvant non-deutérés sur des échantillons statiques ou en flux. Ces travaux ont débouché sur de nouvelles opportunités pour la RMN à bas champ. Plusieurs suivis de réactions, réalisés en ligne et en temps réel, ont été menés à bien sur diverses réactions comme le couplage de Heck-Matsuda, la neutralisation de mimes de gaz moutardes ou encore la synthèse d’un composé naturel par chimie en flux. Par ailleurs, la RMN 2D UF à bas champ a été appliquée avec succès pour discriminer des huiles alimentaires en fonction de leurs origines botaniques. Cette méthodologie 2D, compatible avec des analyses à haut débit, démontre une amélioration notable par rapport à la RMN 1D
High-field NMR based on superconducting magnets involves an expensive and bulky equipment, which has hampered the use of NMR in harsh environments. A new generation of benchtop NMR spectrometers, compact and cryogen free, has brought NMR spectroscopy under the chemist’s fume-hood and as close as possible to production sites. The driving force of this PhD project is to improve the analytical performance of these benchtop NMR systems. We report here the first implementation of Ultrafast (UF) 2D NMR- a method yielding 2D NMR spectra in a single scan- as well as modern gradient-based solvent suppression methods on a 43 MHz benchtop spectrometer, including a B0-gradient coil. Substantial optimizations have led to UF experiments at low-field (LF) with a reasonable performance while the acquisition duration is reduced by one order of magnitude. Then, the presence of non-deuterated solvents –commonly used in LF NMR– has been tackled by the development of suppression methods both in static and flowing conditions. This methodological effort has opened new opportunities for benchtop NMR applications. Several on- and in-line real-time monitorings have been performed on different types of chemical reactions: Heck-Matsuda coupling reaction, oxidative neutralization of mustard-gas simulants or even the synthesis of a natural product in flow-chemistry. Besides applications to process monitoring, UF 2D NMR at 43 MHz has been successfully applied to discriminate the botanical origins of a panel of edible oils. This fast 2D approach has provided a better classification than standard 1D experiments while remaining compatible with high-throughput analysis
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Li, Jian. "Using cadmium-113 NMR spectrometry to study metal complexation by natural organic matter." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/25720.

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13

Petry, David P. "Silicalite Clear Sol Precursors Studied by NMR, Mass Spectrometry and Dynamic Light Scattering." Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525295.

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14

Kindahl, Lill. "Structural studies of saccharides and glycopeptides in aqueous solution by ¹H NMR spectroscopy /." Uppsala : Dept. of Chemistry, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/a377.pdf.

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15

Weekes, Anna L. "Design and construction of an ultrasonic probe for use in a Cryo-Magnet NMR Spectrometer." Thesis, Aston University, 1998. http://publications.aston.ac.uk/9612/.

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SINNMR (Sonically Induced Narrowing of the Nuclear Magnetic Resonance spectra of solids), is a novel technique that is being developed to enable the routine study of solids by nuclear magnetic resonance spectroscopy. SINNMR aims to narrow the broad resonances that are characteristic of solid state NMR by inducing rapid incoherent motion of solid particles suspended in a support medium, using high frequency ultrasound in the range 2-10 MHz. The width of the normal broad resonances from solids are due to incomplete averaging of several components of the total spin Hamiltonian caused by restrictions placed on molecular motion within a solid. At present Magic Angle Spinning (MAS) NMR is the classical solid state technique used to reduce line broadening, but: this has associated problems, not least of which is the appearance of many spinning side bands which confuse the spectra. It is hoped that SlNNMR will offer a simple alternative, particularly as it does not reveal spinning sidebands The fundamental question concerning whether the use of ultrasound within a cryo-magnet will cause quenching has been investigated with success, as even under the most extreme conditions of power, frequency and irradiator time, the magnet does not quench. The objective of this work is to design and construct a SINNMR probe for use in a super conducting cryo-magnet NMR spectrometer. A cell for such a probe has been constructed and incorporated into an adapted high resolution broadband probe. It has been proved that the cell is capable of causing cavitation, up to 10 MHz, by running a series of ultrasonic reactions within it and observing the reaction products. It was found that the ultrasound was causing the sample to be heated to unacceptable temperatures and this necessitated the incorporation of temperature stabilisation devices. Work has been performed on the investigation of the narrowing of the solid state 23Na spectrum of tri-sodium phosphate using high frequency ultrasound. Work has also been completed on the signal enhancement and T1 reduction of a liquid mixture and a pure compound using ultrasound. Some preliminary "bench" experiments have been completed on a novel ultrasonic device designed to help minimise sample heating. The concept involves passing the ultrasound through a temperature stabilised, liquid filled funnel that has a drum skin on the end that will enable the passage of ultrasound into the sample. Bench experiments have proved that acoustic attenuation is low and that cavitation in the liquid beyond the device is still possible.
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16

Puschmann, Robert. "Analysis and Quantification of Inositol Poly- and Pyrophosphates by NMR Spectroscopy and Mass Spectrometry." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21044.

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Inositolpyrophosphate (PP-InsP) sind eine Gruppe sekundärer Signalmoleküle, die in einer Vielzahl zellulärer Prozesse, von Phosphathomeostase über Insulinsignalisierung bis Apoptose eine Rolle spielen. Die Art und Weise, wie PP-InsPs ihre Funktion ausführen, noch weitgehend unbekannt. Deshalb wurden zwei neue analytische Methoden basierend auf Kernspinresonanzspektroskopie und Flüssigchromatographie mit Massenspektrometrie-Kopplung (LCMS) entwickelt. Um die limitierende Sensitivität der Kernresonanzspektroskopie zu umgehen, wurde die Synthese von kernspinresonanzaktivem, 13C-markiertem Inositol optimiert. Des Weiteren wurde eine chemoenzymatische Synthese für alle Säugetier-PP-InsP-Isomere entwickelt, die auf der skalierbaren Ausfällung mittels Mg2+ Ionen basiert. Menschliche Zellen wurden mit 13C-Inositol isotopenmarkiert und in den Spektren der Zellextrakte wurde, basierend auf den PP-InsP-Standards, Fingerabdrucksignale identifiziert mit denen die Konzentrationen der dazugehörigen Moleküle bestimmt werden konnte. Die LCMS basierte Methode wurde auf dem Prinzip der Umsetzung von hochgeladenen Inositolpyrophosphaten zu ihren korrespondieren Methylestern mittels Trimethylsilyldiazomethan geplant. Die ungeladenen, permethylierten PP-InsPs wären geeignet für LC-Auftrennungen und MS-Messungen und sollten eine von Kernspinresonanzspektroskopie nicht erreichbare Sensitivität ermöglichen. Die Methode wurde mittels Inositolhexakisphosphat (InsP6), einem einfacheren PP-InsP-Analog, etabliert und methyliertes InsP6 konnte in Mengen von 10 femtomol detektiert werden. Die Adaption der Methode für die PP-InsPs gestaltete sich jedoch herausfordernd, da der Analyt während der Reaktion zersetzt wurde. Ein Wechsel zu Diazomethan als Methylierungsagens zeigte vielversprechende Resultate.
Inositol pyrophosphates (PP-InsPs) are a well conserved group of second messengers that are involved in a plethora of cellular processes including phosphate homeostasis, insulin signaling, and apoptosis. Despite much effort, it is still mostly unknown how PP-InsPs exert their diverse functions. In order to decipher the mechanisms, researchers have relied either on metabolic labeling with radioactive inositol or on electrophoretic separation on polyacrylamide gels but these methods either lack ease of use or sensitivity. Therefore, two new analytical tools, based on nuclear magnetic resonance (NMR) spectroscopy, and liquid chromatography coupled mass spectrometry (LCMS), were developed. To overcome the limited sensitivity provided by NMR spectroscopy, a high yielding synthesis of NMR-active 13C-labeled inositol was designed and optimized. Furthermore, a chemoenzymatic synthesis of all mammalian PP-InsPs isomers was developed that relied on a scalable purification strategy utilizing precipitation with Mg2+ ions. Human cells were metabolically labeled with 13C-inositol and the prepared PP-InsPs were used as standards to identify peaks in the NMRspectra. These fingerprint signals enabled the quantification of the corresponding molecules. The LCMS-based method was based on the derivatization of the highly charged inositol pyrophosphates to their corresponding methyl esters by trimethylsilyldiazomethane. The permethylated InsPs and PP-InsPs were suitable for LC separation and MS measurement, and provide a sensitivity unmatched by NMR spectroscopy. The method was established using inositol hexakisphosphate, a simpler analog of PP-InsPs, and methylated InsP6 could be detected at quantities as low as 10 femtomole. However, the adaptation of the derivatization for PP-InsPs proved challenging as the reaction caused degradation of the analyte but strategies to circumvent the decay by changing the derivatization agent to diazomethane were promising.
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17

Chen, Ling. "Improvements in excitation selectivity and spectral precision in Fourier transform NMR and mass spectrometry /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487330761219982.

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18

Shah, Siddharth Prakashchandra. "LIPID COMPOSITIONS OF MICROBIAL ORGANISMS ISOLATED FROM EXTREME ENVIRONMENTS AND THEIR IMPLICATION IN THERMO STABILITY OF BACTERIAL CELL MEMBRANE STRUCTURE." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/419298.

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Chemistry
Ph.D.
Microorganisms with an ability to thrive in harsh environments are referred as “extremophiles”. With advances in biotechnology, interest has grown in the extremophile research because of their unique macromolecules’ characteristics due to their growth environments. Over last decade, researchers have isolated many extremophiles from environments like volcano, salt lakes, hydrothermal vents, deep oceans, Antarctica glaciers etc. Macromolecules of these extremophiles are responsible for their survival in extreme environments. In this research work we have isolated lipid molecules from three different microorganisms. 1) GWE1 strain, a thermophilic bacterium, isolated from dark crusty material from sterilization ovens. 2) 7L strain, a thermophilic bacterium, isolated from Chilean Copahue Volcano. 3) I1P strain, a facultative anaerobe of the family Enterobacteriaceae, recently isolated from Antarctica. Complex lipid arrangement and/or type in the cell membrane are known to affect thermostability of microorganisms and efforts were made to understand the chemical nature of the polar lipids of membrane. In this work, we extracted total lipids from cell membrane, separated them by TLC into various fractions and characterize the lipid structures of fractions with analytical tools such as 1H, 13C, 31P and 2D NMR spectroscopy, ATR-FTIR spectroscopy and MSn spectrometry. In GWE1 strain, we were able to identify glycerophosphoethanolamine, glycerophosphate, glycerophosphoglycerol and cardiolipin lipid classes and an unknown glycerophospholipid class with novel MS/MS spectra pattern. We have also noticed the presence of saturated iso-branched fatty acids with NMR spectra in individual lipid classes. In case of I1P strain, we have identified glycerophosphoglycerol, glycerophosphoethanolamine, glycerophosphate, and acyl glycerophosphoglycerol lipid classes with unsaturated fatty acids in their structure, which could be one of the many reasons for survivability at lower temperatures. In case of 7L strain, we were able to identify glycerophosphoglycerol, cardiolipin, glycerophosphoethanolamine and glycerophosphate lipid classes with saturated iso branched fatty acids. FAME analysis revealed iso-15:0 (52.29 %) and iso-17:0 (18.64 %) as major fatty acyl chains. We did not observe major difference in polar head group composition of lipid classes between thermophiles (GWE1 and 7L) compare to psychrophiles (I1P). Major difference among these three strains was in fatty acid composition of lipid molecule. Both thermophiles showed presence of lipids with long chain saturated fatty acids while I1P showed presence of lipid molecule with unsaturated fatty acid chain. Lipids made of unsaturated fatty acids have lower melting points and they introduce kink in the cell membrane structure. At lower temperatures, these effects allow membrane to maintain fluidity and its functionality, which in turn allows the microorganism to grow at lower temperature. Lipids made with saturated iso branched fatty acid chain have higher melting points and they pack together densely in cell membrane. At high temperature because of higher melting point and dense packing, membrane fluidity is not affected and this effect allows microorganism to grow at the higher temperature. We believe that change in fatty acid composition is one of the many reasons for these microorganisms to survive the extreme condition. Thermostability of the other macromolecules (DNA, enzyme) of these extremophiles is not studied in this dissertation.
Temple University--Theses
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19

Dag, Semiha. "Structural studies of some bacterial lipopolysaccharides and extracellular polysaccharides using NMR spectroscopy and mass spectrometry /." Uppsala : Dept. of Chemistry, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200545.pdf.

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20

Persson, Josef. "Measurement of Reduction Efficiency in Green Liquor Using a NIR Spectrometer." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-318.

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Domsjö Fabriker has earlier installed a Near Infrared (NIR) spectrometer after one of their recovery boilers. The purpose is to monitor the reduction efficiency of the boiler and later do process optimization. In this work calibration models for the instrument have been created. 108 green liquor samples have been extracted. A NIR spectrum was recorded for each sample and the samples were subsequently analyzed in laboratory for total alkali, sulfide and total sulfur. Several calibration models were created with multivariate data analysis and their performance and robustness were compared. The best model was able to predict reduction efficiency with a RMSEP of 2.75 percent units. Moreover, models were created for prediction of total alkali with a RMSEP of 0.108 mol/l, sulfides with a RMSEP of 1.95 g/l, total sulfur with a RMSEP of 2.83 g/l and S/Na2 ratio with a RMSEP of 0.022. The result is good enough that the instrument could be used to optimize the process and monitor process disturbances.
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21

Tolonen, A. (Ari). "Analysis of secondary metabolites in plant and cell culture tissue of Hypericum perforatum L and Rhodiola rosea L." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514271610.

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Abstract Sensitive chromatographic methods were developed for the quantitative analysis of secondary metabolites in Hypericum perforatum (St. John's wort) and Rhodiola rosea (Golden root, rose root) extracts. Sample preparation methods were developed for plant, cell culture and biotransformation suspension matrixes. High performance liquid chromatography (HPLC) was used for the separation of analytes, and chromatographic data was acquired using photodiode array (PDA) detection or atmospheric pressure ionization mass spectrometry (API-MS). Ionization efficiencies with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) were compared under different conditions. Specific mass spectrometric detection methods such as multiple reaction monitoring (MRM) and selective ion monitoring (SIM) were utilized. For identification of known and new secondary metabolites in plant tissues, mass spectrometric methods with triple quadrupole and time-of-flight mass spectrometers were used together with one- and two-dimensional nuclear magnetic resonance spectroscopy (NMR).
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22

Srivastava, Abhishek. "Metabolism and bioactivation of nevirapine in humans and rats : Integrated application of NMR and mass spectrometry." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526804.

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23

Sanh, Alan Dominique. "Peptide-RNA recognition : investigation of non-covalent interactions using ESI-mass spectrometry and proton NMR spectroscopy." Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/352.

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24

Oriola, Folch Marta. "Non-destructive condition assessment of painting canvases using NIR spectrometry." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/663091.

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El soporte de tela de los cuadros se compone mayoritariamente de celulosa. Una de las vias de degradación de la celulosa es la hidrólisis ácida, que implica que en un ambiente ácido (bajo pH), la degradación se produce a una velocidad mayor. La principal consecuencia de esta acidez es la ruptura de las cadenas del polímero de celulosa que se mide a través del grado de polimerización (DP). Una disminución del DP implica que las fibras y los tejidos tienen una resistencia mecánica menor, y consecuentemente este parámetro se puede utilizar para monitorizar el estado de conservación de estos materiales. Así pues, el conocimiento de estos dos parámetros, pH y DP puede ser muy útil para la mejor conservación del soporte textil de los cuadros. El objetivo principal de esta tesis ha sido determinar si el espectrómetro de infrarrojo cercano (NIR) Labspec 5000, se podría calibrar para que, de manera totalmente no destructiva, pudiera determinar el estado de conservación del soporte de tela de los cuadros a través de medir el pH y el DP. Esto efectivamente se consiguió utilizando la herramienta de quimiometría PLS (Partial Least Squares). Se obtuvieron errores de predicción de ±0.43 para el pH y de ±275 para el DP. La calibración para la identificación del tipo de fibra también se pudo hacer utilizando el Discriminant Analysis, otra herramienta de la quimiometría. Para poder construir el método NIR no destructivo, primero había que analizar de manera destructiva un número significativo de muestras que fueron tomadas de cuadros mayoritariamente de los siglos XIX y XX. El segundo objetivo principal de esta tesis ha sido conocer cuáles son los valores típicos de pH y DP y el tipo de fibra de los cuadros. Por lo que a esto se refiere, los resultados han sido que la tela de los cuadros tiene, la mayoría de las veces, un carácter ácido (la media de los resultados de todos los cuadros fue de pH 5.51, con una desviación estándar de 0.66). El estudio del pH ha permitido constatar que la tela de los reentelados realizados con pasta de harina, en general, es claramente más ácida que la tela de los cuadros no reentelados. En relación al tipo de fibra, se ha detectado que las telas de yute són más ácidas que las de lino y algodón. No se ha encontrado una relación directa entre la fecha de los cuadros y su valor de pH, y sólo una ligera relación entre la fecha y el DP. Se detectó que pH y DP están fuertemente correlacionados, aunque no de manera directa, cosa que implica que hay otros factores como el tipo de fibra, la fecha del cuadro u otros, que influyen en la correlación entre estos dos parámetros. El tercer objetivo principal de esta tesis ha sido establecer el significado de los varios valores de DP por lo que se refiere al estado de conservación de la pintura sobre tela. Esta información junto con el valor de pH, sirvió para diseñar una ¿Clasificación según el estado de conservación¿, cosa que habría de permitir establecer una organización de los cuadros según las acciones de conservación-restauración a emprender. Se realizó un test con la participación de un grupo de conservadores-restauradores especializados en pintura sobre tela y procedentes de distintos países que permitió ver que la apreciación subjetiva del conservador-restaurador sobre el estado de conservación de las muestras de tela, en general se corresponde con el grado de polimeración de éstas. A través de los resultados de este estudio se pudo establecer que el valor de ¿DP crítico¿ para un cuadro está en <400 y el valor de ¿DP seguro¿ está en >1400. La ¿Clasificación según el estado de conservación¿ se diseñó teniendo en cuenta toda esta nueva información y por eso se priorizó el tratamiento de aquellos cuadros con una tela más ácida pero con valores de DP todavía no muy bajos, puesto que los resultados indicaban que estos cuadros serían los que más se beneficiarían de algún tipo de tratamiento de desacidificación (activo o pasivo). El último objetivo de la tesis ha consistido en aplicar la técnica NIR no destructiva desarrollada, así como la ¿Clasificación según el estado de conservación¿ sobre un caso real de pinturas pertenecientes al Museu Nacional d¿Art de Catalunya (MNAC), fechadas alrededor del año 1900. También se ha estudiado un grupo menor de cuadros de Salvador Dalí de la Fundació Gala-Salvador Dalí. Los resultados han corroborado por un lado la buena aplicabilidad del método no destructivo dessarrollado y, por otro, la acidez (y la presencia de cierta degradación) de la tela de todos los cuadros. Habiendo confirmado, tanto que la tela de los cuadros es mayoritariamente ácida como la influencia que ésta tiene en la velocidad de su degradación, se considera que es de vital importancia empezar a tomar medidas para contrarrestar la acidez de las telas; especialmente si la intención es no aplicar operaciones tan intrusivas como el reentelado en los cuadros durante el máximo tiempo posible. Juntamente con esto, se detecta que es necesaria mucha más investigación sobre los efectos positivos y negativos de la desacidificación de la tela de los cuadros, así como también el estudio de los orígenes concretos de esta acidez (materiales originales, materiales de restauración, entorno de las obras, etc.).
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Samino, Gené Sara. "Mass spectrometry and nuclear magnetic resonance based metabolomics applied to the study of polycystic ovary syndrome." Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/128209.

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Objectives: Three objectives of this thesis have been: (i) Mastering of the main analytical platforms used in metabolomics, (ii) Developing an untargeted metabolomic workflow, involving novel aspects of sample preparation, and data processing for metabolite identification, (iii) Implementing our untargeted metabolomic workflow to the study of human patients with Polycystic Ovary Syndrome (PCOS) and their response to drug treatment Results: In Work 1: Optimization metabolite extraction conditions for NMR analysis, followed by LC/ESI-MS by using the same sample extract with no need for solvent exchange or further pretreatment. In Work 2: Investigate the impact of different aspects of univariate statistical analysis on untargeted LC-MS based metabolomic experiments. In Work 3: Implementation of GC-MS untargeted metabolomic approach to provide new insights on the impact that obesity exerts on the metabolic derangements associated with PCOS. In Work 4: Implementation of multiplatform metabolomics approach based on NMR and LC-MS to provide new insights in PCOS disease in a cohort of young lean PCOS patients. In Work 5: Implementation of multiplatform metabolomics approach based on NMR, GC-MS and LC-MS to provide new insights on the action of drug polytherapy to PCOS disorder. Conclusion: Metabolomics can be consider as a powerful tool for the study of metabolic disorders. Furthermore, metabolite profiling has demonstrated feasibility and flexibility for revealing new mechanistic insights in metabolic disorders that are not been consider when classical analysis is used. Therefore, our metabolomic analysis have demonstrated a great potential as a useful diagnostic technique and can facilitate monitoring of both disease progression and effects of therapeutic treatment.
Objetivos: El presente trabajo tiene dos objetivos generalizables que han sido estudiados con más detalle en la presente tesis doctoral. El primero de ellos es mejorar aspectos metodológicos en el ámbito de la metabolómica y el segundo ha sido la aplicación de la metabolómica en el estudio del síndrome del ovario poliquístico (PCOS). Resultados: Del primer objetivo se han realizado dos trabajos: en el primero, la optimización de un método de extracción común para analizar muestras biológicas en dos plataformas analíticas complementarias utilizadas en metabolómica como son la resonancia magnética nuclear y la espectrometría de masas. Del segundo trabajo realizado se han obtenido unas pautas para abordar los retos que surgen del análisis de datos de metabolómica en espectrometría de masas. Del segundo objetivo también han sido realizados dos trabajos: en ambos se ha utilizado la metabolómica no dirigida para abordar el estudio del PCOS. En el primer trabajo, se ha utilizado la metabolómica para conocer el impacto que ejerce la obesidad en los trastornos metabólicos asociados al PCOS. En el segundo trabajo, se ha utilizado la metabolómica no dirigida para evaluar como afecta la aplicación de una politerapia con medicamentos al metabolismo de pacientes con PCOS. Conclusión: La metabolómica puede ser utilizada como una nueva herramienta para estudiar los trastornos metabólicos.
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Paudel, Liladhar. "High Field 1H Nuclear Magnetic Resonance (NMR) Spectroscopy Based Metabolomics and Complex Mixture Analysis by Multidimensional NMR and Liquid Chromatography-Mass Spectrometry (LC-MS)." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1343403647.

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Forshed, Jenny. "Processing and analysis of NMR data : Impurity determination and metabolic profiling." Doctoral thesis, Stockholm : Dept. of analytical chemistry, Stockholm university, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-712.

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Vilenius, Esa. "On the analysis of near-infrared point spectrometer data for the investigation of lunar surface mineralogy." [Katlenburg-Lindau] Copernicus Publ.***5004719, 2009. http://d-nb.info/996869182/04.

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Ajimo, Jacob. "A UV-Visible-NIR, Time-Resolved Fluorescence Spectrometer for High-Pressure Biological Studies." Miami University / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=miami1134160375.

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30

O'Kennedy, Sean James. "A kinetic and thermodynamic study of procyanidin oligomer conformation by 1H NMR and DFT." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/98054.

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31

Chen, Yanyi. "Dissecting Key Determinants for Calcium and Calmodulin Regulation of GAP Junction and Viral Protein." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/chemistry_diss/64.

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Calcium and calmodulin are implicated in mediating the Ca2+-dependent regulation of gap junctions that are essential for the intercellular transmission of molecules such as nutrients, metabolites, metal ions and signal messengers (< 1000 Da) through its specialized cell membrane channels and communication to extracellular environment. To understand the key determinants for calcium and calmodulin regulation of gap junction, in this study, we identified a calmodulin binding domain in the second half of the intracellular loop of Cxonnexin50 (the major gap junction protein found in an eye lens) using peptide fragments that encompass predicted CaM binding sites and various biophysical methods. Our study provides the first direct evidence that CaM binds to a specific region of the ubiquitous gap junction protein Cx50 in a Ca2+-dependent manner. Furthermore, two novel CaM binding regions in cytosolic loop and C-termini of Connexin43 (the most ubiquitous connexin) have been shown to interact with CaM with different binding modes in the presence of Ca2+ using high resolution NMR. Our results also elucidate the molecular determinants of regulation of gap junction by multiple CaM targeting regions and provide insight into the molecular basis of gap junction gating mechanism and the binding of CaM to the cytoslic region Cx43-3p as the major regulation site. Upon response to the cytosolic calcium increase, CaM binds to the cytosolic loop to result in the conformational change of gap junction and close the channel. It is possible for CaM to use an adjacent region as an anchor close to the regulation site to allow for fast response. Since a large number of residues in the Cxs mutated in human diseases reside at the highly identified CaM binding sites in Cxs, our studies provide insights into define the critical cellular changes and molecular mechanisms contributing to human disease pathogenesis as part of an integrated molecular model for the calcium regulation of GJs. In addition, we have applied the grafting approach to probe the metal binding capability of predicted EF-hand motifs within the streptococcal hemoprotein receptor (Shr) of Streptococcus pyrogenes as well as the nonstructural protein 1 (nsP1) of Sindbis virus and Poxvirus. This fast and robust method allows us to analyze putative EF-hand proteins at genome-wide scale and to further visualize the evolutionary scenario of the EF-hand protein family. Further, mass spectrometry has also been applied to probe modification of proteins such as CaM labeling by florescence dye and 7E15 by PEG.
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Rigau, Roca Laura. "Identification of protein-ligand interactions by mass spectrometry and NMR, case studies: LFA-1, Bcl-xl and Bcl-2." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492546.

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Current genomic and proteomic research is generating a considerable number of potential new therapeutic targets. To tackle all these pharmacological targets, the development of rapid and reliable screening methods, which give information on protein-ligand interactions, are of great importance. New advances in these technologies are often emerging and more will surely follow.
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Abdullah, Sewa Faraj. "Proteomics approaches to polyketide synthases interfaces by mass spectrometry and NMR spectroscopy and the application of chemometrics to metabolomics." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682232.

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Proteomics is a rapidly growing discipline dealing with structure, molecular interactions, conformational dynamics, modifications and the functions of proteins. Mass spectrometry (MS) and (nuclear magnetic resonance) (NMR) have been used comprehensively to study protein interactions. Acyl carrier protein (ACP) interacts with more than 30 partner proteins during either fatty acid or polyketide biosynthesis. In order to be fully activated ACP gains a 4'-phosphopantetheinyl (4'-PP) group from coenzyme A using acyl carrier protein synthase (AcpS) via posttranslational modification. Protein-protein interactions of the ACP from the actinorhodin (act) polyketide synthase (PKS) complex and AcpS were investigated using oxidative footprinting with hydroxyl radicals generated from the Fenton reaction. Chemical modification of acidic residues was also used to investigate the interaction between these proteins using l-ethyl-3-(3- dimethylaminopropyl) carbodiimide (EDC) this acted as a zero length cross linker to induce modification with Me-Glycine. MS was used to identify the modified residues and peptides and the extent of modification. Several residues were found to be protected in the complex between the two proteins and these may participate in the interaction interface between ACP and ACPS. Isotopically labelled ACP was expressed and purified and multidimensional NMR experiments were recorded to investigate this interaction interface identified using oxidative footprinting techniques. Chemical shift perturbations for ACP residues were calculated, and these revealed that many residues were affected by oxidation of ACP. Oxidation of methionine to methionine sulfoxide was confirmed. Metabolomics is a discipline which deals with metabolites in a biological system. It provides a wealth information for disease diagnosis, drug discovery, toxicology and genetic modification. Attempts have been made in this thesis to utilize metabolomics in biometrics. Mice were used as a model to attempt to determine individuals' age by their scent. In this part of the project chemometric methods were used to discriminate mice using a gas chromatography-mass spectrometry dataset of volatile organic compounds obtained from their urine. Principal component regression (PCR), partial least squares regression (PLSR) and support vector regression (SVR) were used to determine mouse age. Mice could be discriminated by their age using SVR without overfitting the data.
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Gädke, Achim, Markus Rosenstihl, Christopher Schmitt, Holger Stork, and Nikolaus Nestle. "DAMARIS – a flexible and open software platform for NMR spectrometer control: DAMARIS – a flexible and open software platform for NMRspectrometer control." Diffusion fundamentals 5 (2007) 6, S. 1-9, 2007. https://ul.qucosa.de/id/qucosa%3A14270.

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Home-built NMR spectrometers with self-written control software have a long tradition in porous media research. Advantages of such spectrometers are not just lower costs but also more flexibility in developing new experiments (while commercial NMR systems are typically optimized for standard applications such as spectroscopy, imaging or quality control applications). Increasing complexity of computer operating systems, higher expectations with respect to user-friendliness and graphical user interfaces as well as increasing complexity of the NMR experiments themselves have made spectrometer control software development a more complex task than it used to be some years ago. Like that, it becomes more and more complicated for an individual lab to maintain and develop an infrastructure of purely homebuilt NMR systems and software. Possible ways out are: ● commercial NMR hardware with full-blown proprietary software or ● semistandardized home-built equipment and common open-source software environment for spectrometer control. Our present activities in Darmstadt aim at providing a nucleus for the second option: DArmstadt MAgnetic Resonance Instrument Software (DAMARIS) [1]. Based on an ordinary PC, pulse control cards and ADC cards, we have developed an NMR spectrometer control platform that comes at a price tag of about 8000 Euro. The present functionalities of DAMARIS are mainly focused on TD-NMR: the software was successfully used in single-sided NMR [2], pulsed and static field gradient NMR diffusometry [3]. Further work with respect to multipulse/multitriggering experiments in the time domain [4] and solid state NMR spectroscopy multipulse experiments are under development.
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Ma, Cunxian. "Tentative Identification of Hydroxylated 2,2',3,5',6-pentachlorobiphenyl Metabolites in Whole Poplar Plants by a Combination of Chromatographic and Spectrometry Techniques." Thesis, University of Iowa, 2014. https://ir.uiowa.edu/etd/4691.

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2,2',3,5',6-pentachlorobiphenyl (PCB95) is a chiral congener of the persistent organic pollutants (POPs) family of PCBs. It has been shown that chiral PCBs can be enantioselectively transformed into hydroxylated metabolites by cytochrome P450 in animals. Previous studies in our group suggested that PCB 95 can be enantioselectively translocated and metabolized in whole poplar plants. In this work, healthy whole poplar plants were hydroponically exposed to PCB95 for 30 days. Two unknown OH-PCB95 metabolites were detected in the roots by HPLC-MS. Different chromatographic and spectrometry techniques, including HPLC-MS, NMR and GC-MS, were tried to determine the structure of the more abundant metabolite of the two. It was identified to be 4'-OH-PCB95 (4'-95) by GC-MS method. The data show that PCB95 can be transformed into at least two hydroxylated metabolites by whole poplar plants, with one of them being 4'-95. Chiral analysis of 4'-95 by HPLC-MS showed slightly more abundance of the second eluting enantiomer E2-4'-95 in the roots, suggesting that the biotransformation of PCB95 to 4'-95 is enantioselective. Comparison with animal studies shows a distinct metabolite profile in whole poplar plants.
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Joubert, Valentin. "Analyse isotopique positionnelle pour les sciences forensiques : développement et utilisation de la spectrométrie RMN quantitative 13C and 15N NMR spectrometry." Thesis, Nantes, 2018. http://www.theses.fr/2018NANT4078/document.

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Dans la bataille contre le trafic des stupéfiants, c’est le concept de profilage du produit illicite qui est couramment utilisé comme outil de lutte contre les réseaux de distribution de la drogue. Ce profilage est réalisé à partir des teneurs en impuretés de synthèse, des solvants résiduels, etc. Le projet ANR FRIIME propose de suivre le même objectif en utilisant la teneur isotopique comme marqueur intrinsèque de la molécule cible. Jusqu’à présent seule la teneur moyenne en isotope a été exploitée et mesurée par spectrométrie de masse isotopique (SMRI). En recourant à une technologie innovante utilisant la résonance magnétique nucléaire (RMN), la capacité de mesurer site par site les teneurs isotopiques, donne maintenant accès à de nouvelles informations. Ces travaux de thèse reposent sur l’optimisation d’une séquence multi-impulsionnelle (INEPT) permettant d’améliorer significativement la sensibilité de la RMN 13C et d’assurer un traçage isotopique complet des molécules de taille importante. Ce nouvel outil sera testé sur des échantillons réels de drogue pour lesquels les agents de coupage seront analysés afin d’obtenir un profil isotopique marqueur de leur origine. De nouvelles informations sur les réseaux seront ainsi collectées. Pour la première fois, ce savoir-faire sera également transposé à l’analyse isotopique positionnelle en 15N par RMN quantitative comme contribution pour les analyses d'explosifs comme le 2,4,6-trinitrotoluène (TNT)
In the battle against the illicit drugs market, this is drug profiling which is currently used as a tool to track drugs trafficking routes. Profiling methods can rely on synthetic impurities, residual solvents, etc. In the ANR project FRIIME, the same objective will be pursued but using the intrinsic marker of the isotopic content of the target molecules. So far, only overall isotopic content has been exploited and measured by isotope ratio mass spectrometry (irm-MS). By using innovative methods employing nuclear magnetic resonance (NMR), the study of the position-specific isotopic distribution of the targeted products is now obtained. This work was based on the optimization of a multi-pulse sequence (INEPT) enabling to improve significantly NMR 13C sensitivity in order to ensure full isotopic tracing on large molecules. This new tool will be tested on real samples of drug for which the cutting agents will be analyzed to have an isotopic profile marker of their origin. Then new information on networks will be obtained. For the first time, this knowledge will be transposed to 15N position-specific isotopic analysis by quantiative NMR as contribution for explosives analyses as 2,4,6-trinitrotoluene (TNT)
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37

Kew, William. "Tested to destruction : advanced spectroscopic, spectrometric, and chemometric analysis of Scotch whisky." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33189.

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Scotch Whisky is a complex mixture comprising thousands of chemical species at a diverse range of concentrations. The identities, origins, and significance of many of these compounds is largely unknown. Routine characterisation of Scotch Whisky mostly utilises techniques such as gas or liquid chromatography (GC, LC) coupled to a FID, UV, or low-resolution mass spectrometry (MS) detector. In this thesis, advanced spectroscopic and spectrometric techniques are investigated as potential complementary means to unravel the chemical complexity of Scotch Whisky. Chemometric methods are applied to decipher the significance or potential origin of many of these compounds. Being predominantly (ca. 99 %) protonated 'solvent' - ethanol and water - 1H and 13C Nuclear Magnetic Resonance (NMR) required solvent suppression to be implemented into the acquisition of high resolution spectra. A 1D NOESY-presaturation sequence was modified and implemented in automation for this purpose. Furthermore, this solvent suppression was coupled with several 1D and 2D homo- and heterocorrelated NMR experiments for the analysis of Scotch Whisky. With limited sample preparation - only addition of buffer - an approximate limit of detection of 50 μm was achieved. The developed NMR methodology was subsequently used for structural elucidation of dozens of compounds in Scotch Whisky. Quantification of these compounds was hindered by variable chemical shifts, signal overlap, and for some compounds the existence of equilibria of different forms. Quantification of ethanol concentrations in model solutions and genuine Scotch Whisky samples was successful. A large set of Scotch Whisky samples were analysed by the solvent suppressed 1D 1H NMR methodology and various statistical techniques including statistical total correlation spectroscopy (STOCSY), independent and principal component analysis (ICA, PCA), and orthogonal partial least squares discriminant analysis (OPLS-DA). Various parameters were modelled, and discrimination of 'malt' or 'blend' status was achieved, whilst maturation wood type discrimination was less successful. High resolution negative mode electrospray ionisation (ESI) Fourier transform ion cyclotron resonance (FTICR) MS was then used to examine a large set of Scotch Whisky samples. Thousands of unique molecular formulae were assigned within a 1 ppm threshold, representing an assignment rate of 72-88 % of the detected peaks in the spectra. Assignments were selectively confirmed by isotopic fine structure (IFS) analysis, and structural information obtained by both quadrupolar isolation and fragmentation, and in-cell isolation and fragmentation. Similar chemometric methods as applied to NMR data were used to model sample parameters, and identification of potential maturation wood marker compounds was achieved. Alternative ionisation sources - including atmospheric pressure chemical- and photo-ionisation (APCI, APPI), and laser desorption ionisation (LDI) - were compared for the analysis of Scotch Whisky by FTICR MS. The differing sources provide complementary compositional information on the sample set, with APCI and LDI being most different to ESI in terms of compounds ionised and spectral profiles. Positive mode ionisation was also successful, but molecular formula assignment was hindered by insufficient resolving power. Late experimentation pushed the achievable resolving power to 2.8 million at m/z 400, however the required approach is significantly more time consuming and prone to signal quality degradation. Formula assignment software, both commercial, open source, and in-house developed, were compared. The commercial and published open source software provided essentially identical results for Scotch Whisky, and whilst the in-house tools assigned fewer species (a subset of those assigned by the other tools), they did so with a smaller mean error of assignment. Various analysis and visualisation tools for MS data of complex mixtures were also developed.
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YOSHIMURA, Etsuro, Mariko AKASHI, Tomonari UMEMURA, and Kin-ichi TSUNODA. "Identification of Al(III) Species in a Solution Containing Equimolar Concentrations of Al(III) and Citric Acid Using Varying-Temperature Al NMR Spectrometry." 日本分析化学会, 2000. http://hdl.handle.net/2237/8749.

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39

Zoppi, Ugo. "Isobar suppression in accelerator mass spectrometry /." [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10373.

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40

Atadana, Frederick Williams. "Catalytic Pyrolysis of Cellulose, Hemicellulose and Lignin Model Compounds." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31251.

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The effect of HZSM-5 catalyst and NaOH pretreatment on the product distribution and bio oil properties from pyrolysis of cellulose, hemicellulose and lignin model compounds was investigated at 450 °C. NaOH pretreated and untreated cellulose was pyrolyzed on sand and the HZSM-5 catalysts; VPISU001 HZSM-5, BASF HZSM-5, and Sud-Chemie HZSM-5. The pyrolysis of cellulose on BASF and Sud-Chemie HZSM-5 catalysts increased the yields of the organic liquid fraction, total liquid and char while decreasing the gas yields. However the catalyst decreased the organic and char yields while increasing the water yields but there was no change in gas yields. The NaOH treatment caused a decrease in the organic and total oil yields relative to the control but the char yield increased. The change in gas yields was not significant. The characterization of the oils using FTIR and 13Câ nmr showed that, the VPISU001 HZSM-5 with and without NaOH pretreatment caused elimination of the levoglucosan fraction while increasing the aromatic fraction. The NaOH pretreated cellulose pyrolyzed on sand reduced the levoglucosan groups while increasing the aromatic fraction of the bio oil. In the hemicellulose studies, birchwood xylan and NaOH treated xylan samples were pyrolyzed on sand and VPISU001 HZSM-5 catalyst. The organic liquid yields were very low and ranged from 3.3 wt% to 7.2 wt%, the water yields ranged from 17.8-25.7 wt%, the char yield were 17.8-25 wt% and gas yield were 40.9-49.6 wt%. The HZSM-5 catalysts increased the water and gas yields and produced the lowest char yield. NaOH pretreatment produced the lowest water yield while the char yield was the highest. The combined effect of NaOH pretreatment and HZSM-5 produced the lowest organic yield and highest char yield. The FTIR and 13C-nmr analyses of the organic liquids showed that the HZSM-5 catalyst promoted the formation of aromatic products, while the NaOH pretreatment promoted the formation of aliphatic hydrocarbons. The combined effect of NaOH pretreatment and HZSM-5 catalyst seem to promote the formation of anhydrosugars. The main gases evolved were CO, CO2 and low molecular weight hydrocarbons. The HZSM-5 catalyst promoted CO formation while NaOH pretreatment promoted CO2. The HZSM-5 catalyst produced the highest yield of low molecular weight hydrocarbon gases. The lignin and model compounds studies involved using low molecular weight kraft lignin, guaiacol, and syringol which were pyrolyzed on sand and VPISU001 HZSM-5 catalyst at 450 °C. The kraft lignin pyrolysis produced low liquid and gas yields and high char yields. The HZSM-5 catalysts increased the water yield and decreased the organic liquid yield. NaOH pretreatment increased the char yield and decreased the liquid products. NaOH and the HZSM-5 catalyst together decreased the char and increased the gas yields. The 13C-nmr and FTIR analysis showed that NaOH pretreatment promoted the formation of mainly guaiacol while the HZSM-5 catalyst formed different aromatic components. NaOH pretreatment promoted the formation of more CO2 than CO whilst HZSM-5 catalyst promoted the formation of more CO than CO2. Methane formation was enhanced by NaOH pretreatment. Other hydrocarbon gases were however enhanced by the HZSM-5 catalysts. Pyrolysis of the model compounds on the HSZM-5 catalyst showed an increase in pyrolytic water. The HZSM-5 catalyst promoted demethylation in syringol pyrolysis as compared to guaiacol.


Master of Science
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41

Bajwa, Tejbir Singh. "Development of a software tool to perform qualitative analysis on spectral data obtained from a NIR-MOEMS spectrometer." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464416.

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42

Wilson, Peter Stanley. "Rediscovering Arsenoacetic Acid." The University of Waikato, 2009. http://hdl.handle.net/10289/2778.

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Arsonoacetic acid, H₂O₃As¹CH₂COOH, and arsenoacetic acid, punitively [AsVCH₂COOH]₂ have been synthesised according to historical literature methods, and have been characterised using modern techniques. Arsonoacetic acid was shown by an X-ray crystal structure analysis to be a molecular species with an extensive hydrogen bonding network in the crystal. Arsenoacetic acid proved to be more enigmatic. Electrospray mass spectra suggested it consisted of a mixtures of rings (RAs)n, n = 3-11, with n = 6 dominating. This was partly confirmed by a crystal structure of (AsCH₂COOH)₆ (as the pyridine solvate). On the other hand, ¹H and ¹³C NMR gave spectra that indicated only a single component for arsenoacetic acid. The formation of crystals of the high temperature phase of elemental sulfur, β-S8, at ambient temperature is also discussed.
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Marin, Córdoba Roberto. "Chromium carcinogenesis characterization of DNA damaging intermediates by EPR ³¹P NMR, HPLC, ESI-MS and magnetic susceptibility /." Ohio : Ohio University, 2010. http://www.ohiolink.edu/etd/view.cgi?ohiou1261417590.

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Chen, Kan. "Applications of Mass Spectrometry to Analysis of Prodiginines, Bioactivated Methylenedianiline Intermediates, and Hypoxia Induced Changes in the Zebrafish Skeletal Muscle Proteome." ScholarWorks@UNO, 2008. http://scholarworks.uno.edu/td/899.

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Mass spectrometry coupled with liquid chromatography and gel electrophoresis enables separation and detection of components in a complex mixture. During the last two decades, its applications were dramatically extended and remarkable progress has been made in many fields, in particular, environmental and biological analyses. This dissertation focuses on identification and characterization of biologically active compounds and comparative analysis of protein expression changes. The first two projects (Chapters 2 and 3) focus on the application of LC/MS approach to profile the bioactivated intermediates of 4, 4'-methylenedianiline (DAPM) from rat vascular smooth muscle cells (VSMCs) and bile. In our study, several DAPM metabolites were detected and characterized in detail by liquid chromatography-electrospray tandem mass spectrometry. The structural assignments of these metabolites from VSMCs and rat bile significantly improve our understanding of DAPM biotransformations and toxicity. The third project described in Chapter 4 focuses on using electrospray tandem mass spectrometry (ES-MS/MS) and theoretical calculation (GAUSSIAN 03 program) to investigate the unusual methyl radical loss and consecutive fragment ions that dominate the low-energy collision induced dissociation (CID) mass spectra of prodiginine compounds. Structures of the fragment ions are proposed and explanations are given to rationalize the observed competition between the formation of even-electron ions and radical ions. Our study shows that the lower apparent threshold associated with methyl radical loss points to a lower kinetic barrier. In Chapter 5, hypoxia-induced changes of zebrafish skeletal muscle were studied using two-dimensional difference in-gel electrophoresis (2D-DIGE) in vivo after 48 h in hypoxia vs. normoxia. The results showed that proteins involved in mitochondrial oxidative metabolism are down-regulated, whereas glycolytic enzymes are up-regulated to compensate for the loss of ATP synthesis in aerobic metabolism. The up-regulation of two spots identified as hemoglobin variants was also observed. These protein expression changes are consistent with a hypoxic response that enhances anaerobic metabolism or O2 transport to tissues.
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Brodbeck, Roland. "Balloon-borne far-infrared Fabry-Perot spectrometer for astrophysical observations /." [S.l.] : [s.n.], 1997. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=12510.

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Puschmann, Robert [Verfasser], Dorothea [Gutachter] Fiedler, Christian P. R. [Gutachter] Hackenberger, and Michael [Gutachter] Hothorn. "Analysis and Quantification of Inositol Poly- and Pyrophosphates by NMR Spectroscopy and Mass Spectrometry / Robert Puschmann ; Gutachter: Dorothea Fiedler, Christian P. R. Hackenberger, Michael Hothorn." Berlin : Humboldt-Universität zu Berlin, 2020. http://d-nb.info/1203624190/34.

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Piecuch, Scott. "A Fast NIR Spectrometer for Examining Explosive Events: Emission of PETN Based Explosives and H₂O Absorption Method Feasibility." [Milwaukee, Wis.] : e-Publications@Marquette, 2009. http://epublications.marquette.edu/theses_open/13.

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Marchand, Jérémy. "Combining NMR and MS fingerprinting for fine characterization of lipid profiles. : Application to a chemical food safety issue." Thesis, Nantes, Ecole nationale vétérinaire, 2018. http://www.theses.fr/2018ONIR120F/document.

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Pour garantir au consommateur des aliments sûrs, l'emploi d'anabolisants chez les animaux de production est prohibée au sein de l'Union Européenne depuis la fin des années 1980. Bien que performantes, les méthodes de contrôle classiques ciblées font face à de nouveaux défis auxquels des stratégies alternatives (non ciblées),visant à identifier des biomarqueurs métaboliques caractéristiques de l'effet associé à ces pratiques, offrent des solutions innovantes. Le lipidome en particulier constitue une fraction d'intérêt pour l'étude des effets liés aux agents de répartition. La Spectrométrie de Masse (SdM) et la Résonance Magnétique Nucléaire (RMN) sont alors classiquement utilisées, indépendamment. Ce travail propose d'évaluer leur combinaison, bénéficiant des niveaux d'information différents associés, et les conséquences en termes de gain de prédiction ou d'identification des biomarqueurs. Comme modèle d'étude, des échantillons sanguins provenant d'animaux traités avec un agent de répartition connu pour perturber les profils lipidiques,ont été caractérisés. L'analyse du lipidome sérique par SdM a impliqué trois plateformes offrant des angles de vue différents afin de fournir une couverture étendue; l'étude de leur cohérence et complémentarité constituant l'un des objectifs de cette thèse. En parallèle, l'analyse par RMN a requis le développement d'une procédure complète, de l'optimisation des conditions de préparation d'échantillon aux paramètres d'acquisition, incluant des approches de RMN 2D rapides récentes. Enfin, le verrou associé à l'analyse des données issues des différentes sources a permis d'évaluer des approches statistiques innovantes, notamment multibloc
Ln order to ensure safe food products for the consumer, the use of growth promoters in livestock farming has been prohibited in European Union since the end of the 80s. Although efficient, the conventional targeted control methods face new challenges to which alternative strategies (untargeted), aiming at identifying metabolic biomarkers characteristic of the effects induced by such practices, provide innovative solutions. In particular, the lipidome is an area of interest to investigate the effects associated with repartition agents. Mass Spectrometry (MS) and Nuclear Magnetic Resonance (NMR) are then classically used independently. This PhD work intends to evaluate their combination benefiting from the different levels of associated information and the consequences in terms of enhanced prediction or biomarker identification. As a study model, blood samples from animals treated with a repartition agent known to disrupt lipid profiles were characterized. The investigation of the serum lipidome with MS involved three distinct platforms providing different outlooks in order ta generate extended coverage; the study of their consistency and complementarity constituting one of the objectives of this PhD. In parallel, the analysis with NMR prompted the development of a complete workflow, from the optimization of the sample preparation conditions to acquisition parameters -including recent fast 2D NMR approaches. Finally, the challenge associated with the analysis of data from multiple sources allowed ta evaluate innovative statistical approaches such as multiblock analysis
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Roos, Felix Franz. "Algorithms for peptide identification by tandem mass spectrometry /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16844.

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Sierk, Bernd. "Solar spectrometry for determination of tropospheric water vapor /." Zürich, 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13850.

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