Dissertations / Theses on the topic 'Spectrométrie en énergie et de masse'
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Steichen, Valentin. "Développement d’un analyseur en énergie pour la caractérisation des hautes atmosphères neutres et ionisées terrestre et planétaires." Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS635.
Studying the dynamic of particles in the thermosphere – ionosphere and in the exosphere of bodies in the Solar System allows to deepen our understanding of these critical regions that are the bridge between a planet and space. The aim of my thesis was to develop, build and test a neutral particles energy analyser for studying the upper planetary atmospheres: INEA (Ion and Neutral Energy Analyser). The instrument aims to measure the energy structure of the neutral and ion constituents present in the upper atmosphere. To achieve this challenging task, INEA relies on two concepts: an innovative ion source that is based on a carbon nanotube array as an electron emitter and an electrostatic energy analyser which is able to image directly the energy distribution of the particles. During these three years of thesis, a numerical model of INEA was developed in order to meet the instrumental objectives imposed by the measurements needed to characterize the upper atmospheres. At the same time, I have been working on the development of an ion source, also necessary for the optimal operation of INEA, based on the use of carbon nanotubes as electron emitters. The development of the detector, another important part of the instrument has also been conducted. Following the numerical modelling and the work achieved on the different parts of the instrument, a first prototype of INEA has been designed and assembled. This prototype being currently tested. With the work achieved during this thesis, we have been able to propose two instruments for future space missions: M-INEA on the M-MATISSE mission proposed for the ESA M7 call for project, recently selected for a phase A study up to mid-2026, and PSEE, an electron emitter dedicated to the control of PRELUDE SAT, a 6U CubeSat developed by two Japanese universities scheduled to be launched mid-2025
Hue-Faucheur, Nathalie. "Dissociation en phase gazeuse d'ions organiques complexes par collision de haute énergie et spectrométrie de masse tandem." Paris 11, 2002. http://www.theses.fr/2002PA112258.
The ionization techniques which proceed from the bombardment of the sample by fast caesium ions (LSIMS) or from the electronebulization of a solution at atmospheric pressure (electrospray, ESI) have been used during this thesis in association with a multi-sectors tandem mass analyzer. From comparison between MS/MS spectra acquired after high energy collisional activation (in the order of kiloelectronvolt) of ionic species arising from one of these ionization methods, it has been shown that the "production mode" of the ions plays a crucial role in dissociation processes via charge-remote fragmentation (CRF). The internal energy of the precursor ions before the collision affects indeed significantly the dissociation behavior after the collisional activation step. Tandem mass spectrometry in combination with high energy collisional activation (CID-MS/MS) and applied to parent ions generated in the LSIMS or ESI ion source allowed the structural elucidation of various natural compounds in complex mixtures and small amounts. It was thus possible to establish unambiguously the double bonds location or branching pattern for aliphatic long chain molecules: serotonin derivatives, acetogenines and glycosphingolipids, with the occurrence of CRF fragment ions that are very specific and highly informative. In addition the structures of cyclic lipopeptides from the surfactine family and oligosaccharides which possess an alditol function and a carboxylic acid group have been characterized
Minaya, Ramirez Enrique. "Un nouveau piège à ions circulaire pour la spectrométrie de masse et la structure nucléaire." Phd thesis, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00421111.
Becker, Joël. "Étude et développement d'un spectromètre de masse et énergie : modélisation et optimisation de l'optique, réalisation du prototype." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2013. http://tel.archives-ouvertes.fr/tel-00905315.
Bayat, Parisa. "Spectrométrie de masse en tandem pour l'étude des énergies de liaison de complexes "hôte-invité" et l'élucidation structurale d'oligosaccharides." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS108.
In advancing host-guest (H-G) chemistry, considerable effort has been spent to synthesize host molecules with specific and well-defined molecular recognition characteristics including selectivity and adjustable affinity. An important step in the process is the characterization of binding strengths of the H-G complexes. This characterization is typically performed in solution using NMR or fluorescence. Gas-phase investigation of energetics of H-G systems is of great importance in providing information regarding their intrinsic binding properties. The major portion of this thesis is devoted to the study of the energetics of H-G complexes formed by three hemicryptophane cage hosts with various biologically-relevant guest molecules. Among the existing tandem mass spectrometry-based techniques, here we employ blackbody infrared radiative dissociation (BIRD), low-energy collision induced dissociation (low-energy CID), higher-energy collision dissociation (HCD) and high-pressure CID for measurements of energetics of H-G complexes. These techniques were used either alone, or in combination with each other, or with Rice–Ramsperger–Kassel–Marcus (RRKM) modeling. This work has allowed us to develop the low-energy CID, a promising technique, but so far infrequently used
Claverie, Fanny. "Développement et applications d’un système laser femtoseconde infra-rouge basse énergie et haute cadence de tir pour l’analyse d’éléments trace dans les solides par couplage ablation laser / ICPMS." Pau, 2009. https://theses.hal.science/docs/00/40/14/50/PDF/These_Fanny_CLAVERIE.pdf.
Laser ablation inductively coupled plasma mass spectrometry is more and more considered as a tool of choice for solid analysis. The use of femtosecond laser sources permit to improve analytical performances of the coupling thanks to the non-thermal ablation obtained in comparison with the more conventional nanosecond laser used. Through a collaboration between the LCABIE (Laboratoire de Chimie Analytique Bio-Inorganique et Environnement) of Pau and Novalase SA (a company specialized in optical and laser integration), the first integrated femtosecond laser ablation system was designed in 2003. Its unusual characteristics (high repetition rate and scanning beam device) allow to perform some new ablation strategies and open encouraging analytical perspectives in terms of sensitivity and quantification. The potential of this prototype was evaluated through fundamental analyses such as elemental fractionation and characterization of the aerosol produced by laser ablation and through the development of different applications such as analysis of soils and sediments by in-cell isotope dilution, detection of selenoproteins in gel electrophoresis, and determination of uranium isotopic composition of micrometric particles
Yazidjian, Chabouh. "Conception d'un système de détection pour ISOLTRAP et test de l'équation de masse aux multiplets isobariques." Caen, 2006. http://www.theses.fr/2006CAEN2082.
Installed at the on-line isotope separator ISOLDE at CERN, the tandem Penning-trap spectrometer ISOLTRAP is designed to perform high-accuracy mass measurements on short-lived radionuclides. Based on the determination of the ion cyclotron frequency in a strong magnetic field, the typical relative mass uncertainty is 10-8 with a resolving power of up to R=107. Accurate and precise mass values for specific unstable nuclides are important since they serve e. G. As a stringent test of nuclear models. The main part of this work is the design, installation and characterization of a new Channeltron-detector setup in order to increase the detection efficiency of ISOLTRAP by about a factor of 3. Since a detection efficiency close to 100 percent is reached, true single-ion experiments can be performed for the first time and exotic nuclides further away from the valley of stability and with very short half-lives are now accessible. Concerning mass measurements on short-lived nuclides, the masses of potassium isotopes from 35K (178ms) up to 6K (105s) have been measured with a relative precision of better than 1. 6 10-8. The accurate value of the 35K mass contributes to a stringent test of the isobaric multiplet mass equation for the A=35, T=3/2 isospin quartet
Bail, Adeline. "Mesures de rendements isobariques et isotopiques des produits de fission lourds sur le spectromètre de masse LOHENGRIN." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2009. http://tel.archives-ouvertes.fr/tel-00410261.
Nguyen, Duy Luan. "Catalyseurs à base d'or pour la réduction catalytique sélective des oxydes d'azote par les hydrocarbures provenant de sources mobiles." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10133/document.
Nowadays, emissions of atmospheric pollutants from mobile sources such as nitric oxides (NOx) are submitted to more stringent regulations especially within the next Euro 6 which will be implemented in Europe at the beginning of 2014. Up to now commercialized technologies available for the abatement of NOx from lean burn engine (running with a large excess of oxygen) are not capable to remove simultaneously NOx and particulates in lean atmosphere. This study is essentially focused on the NOx conversion to nitrogen via the Selective Catalytic Reduction by using hydrocarbons (HC-SCR) in representative Diesel exhaust gas conditions. This technology is more feasible than the Lean-NOx trap and Urea-SCR systems. Supported gold catalysts on alumina have been developped for the replacement of Pt and Pd less selective. Particular attention was paid to the thermal stability under reaction conditions at 500°C. Among the different synthesis protocols investigated (Deposition-precipitation, Anionic exchange), it was found that the anionic exchange method leads to the best compromise with a larger operating window after ageing. In addition, the reduction of NOx to nitrogen seems structure sensitive, the largest particles being more active than the smallest ones usually thermodynamically instable at high temperature. In this context, such behavior should be profitably used for further practical developments since post-combustion catalysts essentially run at rather high temperature. The second part of this study was dedicated to the modification of Au/Al2O3 catalysts after silver incorporation. Different strategies implemented for Ag incorporation have been examined. Coprecipitation and grafting lead to the formation of bimetallic particles with homogeneous distribution of gold and silver especially via the coprecipitation method. Strong interaction between Au and Ag with further modification of their electronic and adsorptive properties leads to strong deactivation. On the other hand, the segregation of both metals on alumina preserving their intrinsic properties improves the catalytic performances especially after ageing. The influence of different operating condition has been examined showing the best compromise when gold is successively impregnated on Ag/Al2O3
Kennel, Claire. "Mesures expérimentales et modélisation de la formation des oxydes d'azote dans les flammes d'hydrocarbures dopées à l'amoniac." Rouen, 1989. http://www.theses.fr/1989ROUES001.
Suarez, Stéphanie. "Microbiologie clinique et spectrométrie de masse." Phd thesis, Université René Descartes - Paris V, 2013. http://tel.archives-ouvertes.fr/tel-00920410.
Gilles, Isabelle. "Spectrométrie de masse et réactivité chimique." Montpellier 2, 1995. http://www.theses.fr/1995MON20080.
Jeanne, dit Fouque Kevin. "Différenciation de topoisomères peptidiques par spectrométrie de masse à mobilité ionique et spectrométrie de masse en tandem." Rouen, 2016. http://www.theses.fr/2016ROUES020.
Lasso peptides are ribosomally synthesized and post-translationnally modified peptides produced by bacteria, sharing a mechanically interlocked topology that is essential for their biological activity. This PhD work focused on the structural characterization of lasso peptides and differentiation between their branched-cyclic topoisomers using ion mobility – mass spectrometry (IM-MS) and tandem mass spectrometry (MS/MS). IM-MS studies led to the development of a method based on the use of a supercharging reagent, highlighting an additional charge state of multiply protonated species, for which the lasso and branched-cyclic topologies were clearly differentiated and separated in mixture. To assess the developed method, this strategy was also applied to other types of constrained (macrocyclic, disulfide bonds) and unconstrained (linear) structures. IRMPD spectroscopy studies allowed to characterize the changes in the hydrogen bond network, associated with the unfolding of the gas phase conformation, as a function of the charge state of multiply protonated species. The spectroscopic data could thus be correlated with the ion mobility data. IM-MS provides an overview of the conformation through a collision cross section measure (CCS), while IRMPD spectroscopy allows to probe intramolecular interactions through the hydrogen bonds. The structural characterization of lasso and branched-cyclic peptides was also carried out using MS/MS of triply protonated species. These experiments enabled us to establish general rules of fragmentation evidencing lasso topologies in collision induced dissociation (CID) and electron transfer dissociation (ETD)
Domalain, Virginie. "Différenciation de stéréoisomères par couplage, spectrométrie de masse et spectrométrie de mobilité ionique." Rouen, 2014. http://www.theses.fr/2014ROUES023.
This PhD work deals with analysis of stereoisomers, which present very close collision cross section difference (DeltaCCS ≤ Å2), by the coupling of ion mobility spectrometry and mass spectrometry (IM-MS). A study of diastereoisomers M which are functionalized entities found in a lot of natural products, rise to an efficient strategy based on cationisation (with alkali cations X and transition metals (X)II) and formation of multimers [3M+X]+ and [3M+(X)II-H]+ allowing the differentiation and the separation of stereoisomers, particularly enantiomers of amino acids and diastereomers with a major biological interest. It has been highlighted that the cationisation allows a significant increase of the stereoisomers differenciation. Then, we have shown that the nature of asymmetric center substituents plays an important role on the ion mobility separation
Bouclon, Julien. "Spectrométrie de masse FT-ICR bidimensionnelle, développements et applications." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEE002/document.
Mass spectrometry provides two kinds of information: the molecular mass of molecules present in a mixture, obtained all at once (MS), and structure through isolation and fragmentation, obtained one by one (MS/MS). Two-dimensional FT-ICR MS allows simultaneous parallel acquisition of structural information without isolation, regardless of the number of molecules. Nevertheless, the low resolution in the indirect dimension, which could be improved by increasing the acquisition time, seemed to limit this method to a simple curiosity. The first objective is to implement non-uniform-sampling (NUS) in 2D FT-ICR MS. This method consist in the random acquisition of the same number of points in the indirect dimension as in uniform acquisition, but over a wider t1max range. Processing algorithms then reconstruct skipped points, and the result is an increase of signal resolution without wasting analysis time. The first step is to create an algorithm that can generate random sampling with a uniform distribution for an optimal coverage of the t1max range. Processing algorithms may have trouble to reconstruct small peaks when the number of skipped points increases. The second step is to choose the under-sampling ratio for the best compromise between the gain in resolution and the signal-to-noise ratio. The third and last step is to obtain MS/MS spectra with corrects isotopic patterns for fragments produced from heavy isotopes. The second objective is to improve the understanding of ion motions in ICR cells depending on the RF pulses by using Lorentz equations. The first goal is to determine the equations governing precursors motions until their detection. Then the fragmentation will be introduced and analytical solutions describing fragments motions will be established. The last step is to simulate the trajectories of precursors throughout the entire pulse sequence as well as the behavior of fragments clouds, from their formation to detection
Indrajith, Suvasthika. "Croissance moléculaire induite dans les agrégats d'hydrocarbures linéaires par la collision avec des ions et des électrons." Thesis, Normandie, 2021. http://www.theses.fr/2021NORMC201.
The work presented in this thesis concerns the experimental study in gas phase of the collisions between low energy ionizing particles and weakly bonded, neutral clusters of linear hydrocarbons. The purpose of these experiments was to analyze the processes subsequent to the energy and charge transfers during the collision, which are the fragmentation and molecular growth via the formation of covalently bonded molecules forming these clusters. The experimental work in this manuscript has shed light on the respective roles of electronic ionization and the nuclear and electronic stopping powers of projectiles on growth mecanisms within the clusters. To this end, the studies were carried out with low energy ion beams (keV) supplied by GANIL (Caen), which represents the majority of the results presented here, and experiments using electrons were also carried out at the J. Heyrovsky Institute of Chemistry - Physics (Prague, Czech Republic)
Seyer, Alexandre. "Imagerie par spectrométrie de masse : développements méthodologiques et applications biologiques." Thesis, Evry-Val d'Essonne, 2010. http://www.theses.fr/2010EVRY0028/document.
My PhD’s work consisted in continuing the development of Mass Spectrometry Imaging (MSI) methods, in terms of methodology improvements but also through biological applications.The first part concerned the development of a novel sample preparation method dedicated to very small objects for chemical imaging, particularly for TOF-SIMS imaging. This method has been validated by studying different types of flavonoids in from seeds of Arabidopsis thaliana, with a size of 400 nm only. The second part, dedicated to biological applications, is divided into two sections. The first section includes two projects where the goals was to detect and locate, using TOF-SIMS imaging, the active molecule of an anti-acne cream in human skin sections, and a brominated flame retardant, the decabromodiphenyl ether, in target tissues in rats. In the second section, we have studied by MALDI-TOF and TOF-SIMS imaging the lipid absorption during the digestion, and finally, with the help of statistical analysis tools, we compared lipid profiles of healthy samples versus those from cystic fibrosis samples in a model animal of the disease.Through these projects, we have concluded that MALDI-TOF and TOF-SIMS imaging are two complementary techniques, and, when they are combined with statistical analysis, they can be powerful tools
Le, Pogam-Alluard Pierre. "Analyses de lichens par spectrométrie de masse : déréplication et histolocalisation." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S056/document.
Lichens are self-sustaining symbiotic partnerships comprising a fungus associated with a green alga and/or a cyanobacteria. This consortium produces unique secondary metabolites that are endowed with various biological activities. To harness this privileged chemodiversity, innovative mass spectrometry techniques were developed in the course of this study to accelerate the dereplicative holdup through both a minimal sample preparation and a decrease of the time of analysis. Two approaches were considered during this work: DART-MS and LDI-MS and their adequacy for lichen dereplication was assessed on a vast array of samples encompassing a wide range of metabolites. Both of them facilitated complete chemical profiles, respectively from unprocessed lichen material and crude acetone extracts. Since TLC still enjoys a wide-spread popularity among lichenologists, the advantages offered by TLC-ESI-MS hyphenation were evaluated as well. A second part of this manuscript focused on the histolocalization of lichen metabolites. For this purpose, LDI mass spectrometry imaging studies were undertaken on the crustose lichen Ophioparma ventosa. The phytochemical investigation of this species afforded the isolation of six naphthopyranones from its apothecia, four of them being new molecules. LDI-MSI revealed the distribution patterns of all the main metabolites of this lichen, reaching a spatial resolution of 50 μm. Most interestingly, the distribution pattern of imaged metabolites within the thallus is highly organized and is related to their ecological relevance. Joint strategies combining histolocalization and genetic investigation of lichen symbionts separated using laser capture microdissection were also considered. As such, an investigation of the biosynthesis of mycosporine serinol within Lichina pygmaea dissociated symbionts was initiated. Further analytical strategies such as X-ray powder diffraction are introduced in this thesis that contains six publications and two drafts to be submitted
Violet, Perrine. "Étude thermodynamique et experimentale du depôt ald (atomic layer deposition) de TaN et de son precurseur organometallique pdmat T, Ta[N(CH3)2]5, utilisé en microélectronique." Grenoble INPG, 2008. http://www.theses.fr/2008INPG0109.
The study of PDMAT vaporization and thermal cracking under vacuum of has been performed by using respectively Knudsen cell and tandem cells mass spectrometric method. The design and the validation of the reactor, specific to the study by mass spectrometry of the very reactive organometallic molecules in contact with the air, carried out during this thesis, are exposed. In parallel first TaN ALD starting from PDMAT and NH3 were realized in ALD new reactor in progress of optimization and were characterized by electronic microscopy and XPS. The confrontation of these two results makes it possible to propose reactions diagrams occurring at the time of the deposit of TaN in ALD reactor and to determine the structural and thermodynamic properties of identified molecules. These data are used in the various approaches of thermodynamic modeling of processes of growth starting from a gas phase
Légalité, Florent. "Élucidation des mécanismes de dégradation de polluants émergents par couplage électrochimie-spectrométrie de masse ou électrochimie-résonance magnétique nucléaire." Nantes, 2015. http://www.theses.fr/2015NANT2102.
Fate of various xenobiotic (drug or emerging pollutant) constitutes nowadays one of the most important areas of research that aims at tackling societal challenges at the interface of environmental and sanitary stakes. The main objective of this study consists in coupling between an electrochemical cell (EC) with mass spectrometry (MS) or nuclear magnetic resonance (EC- MS and EC-NMR) to simulate oxidative transformation of xenobiotics initiated by cytochrome P450 as well as in environment. The expected results obtained from these hybrid devices led to a better understanding of various mechanism pathways involved during different steps of in vivo or environmental degradation of xenobiotic. Firstly, the elucidation of electrochemical behavior of tetrabromobisphenol A was achieved by identifying oxidation products using EC-(LC-)MS. Secondly, we mimicked electrochemically the in vivo reduction of aristolochic acid (nitro aromatic compound). Special interest has been focused on the formation of reactive intermediates during enzymatic pathways. Finally we present the first coupling between an electrochemical cell and ultrafast 2D NMR. This coupling is useful for in situ real time monitoring of redox products and identification potential reactive intermediate species
Delobel, Arnaud. "Spectrométrie de masse par nébulisation : électronébulisation et photoionisation à pression atmosphérique." Evry-Val d'Essonne, 2004. http://www.theses.fr/2004EVRY0038.
Two ionization methods used in the field of mass spectrometry were studied during this PhD work. Both of these methods – electrospray and atmospheric pressure photoionization – are based on the spraying of a sample solution. Electrospray proved to be able to study macromolecular noncovalent complexes between proteins and metal cations. In the first case, interactions between model proteins and organic gadolinium complexes proved to be weak and aspecific. In the second case, our results showed that a chloroplastic protein involved in photosynthesis – CP 12 – was eable to specifically bind some particular metal cations. Dissociation constants were calculated and important insights into the structural features of CP 12 were obtained. Atmosphéric pressure photoionization, which had sor far never been used for the analysis of biomolecules, happened to be very promising. Duriing the analysis of peptides, singular gragmentation patterns were observed. Very important results, especially from a structural point of vue, were obtained for phosphatidylcholiines and globotriaosylceramides. Underlying physico-chemical processes were tackled, and the rôle of both electron-ion reactions and radical processes were outlined. The results of this PhD work higlilighted the crucial rôle of the ionization methods based on spaying of samples in biomolécular analysis. Mass spectrometry is in many cases and analysis method of choice in molecular biology
Touboul, David. "Imagerie biologique par spectrométrie de masse. Aspect fondamentaux, méthodologies et applications." Evry-Val d'Essonne, 2006. http://www.theses.fr/2006EVRY0010.
My PhD’s work has been completely devoted to develop new imaging mass spectrometry (IMS) techniques, called MALDI-TOF imaging and cluster-TOF-SIMS imaging. The first part of this manuscript was dedicated to instrumental developments. For MALDI-TOF imaging, the goals were to optimize the matrix deposition and to develop methods for identifying biomarkers. For TOF-SIMS imaging, the objectives were to test new cluster ion sources and to perfect structural analysis. Complementarities between these two innovative imaging techniques were also demonstrated. The second part was devoted to biological applications (Duchenne Muscular Dystrophy, Fabry Disease, saponine effects on human melanoma cells) or to surface analysis (archaeological samples and OPLC-IMS). The results of this PhD work enlightened the fact that MALDI-TOF and cluster-TOF-SIMS imaging methods are new powerful tools to study drug distribution and to find new biomarkers in biological tissues
Maire, Florian. "Étude des dendrimères polyamidoamines par spectrométrie de masse et mobilité ionique." Rouen, 2010. http://www.theses.fr/2010ROUES018.
In the first part of this work, we report the formation of unexpected ions during mass spectrometry analysis of a first-generation polyamidoamine dendrimer using an electrospray ionization source in negative ion mode. The study of these ions, corresponded to an increase of 12 Da, showed that an electrical discharge in the electrospray source was the origin of these artefacts. In the second part, we use ion mobility coupled with mass spectrometry as an analytical technique to determine the size of polyamidoamine dendrimers up to generation 3. Our results showed a good agreement with those obtained by molecular models and literature values. Furthermore, polyamidoamine dendrimer isobaric ions were dispersed by the combination of ion mobility and mass spectrometry. The third part deals with the study of non-covalent complexes involving first-generation polyamidoamine dendrimer and single stranded oligonucleotides. MS/MS fragmentation of these complexes was different according to the charge state of the complex and the oligonucleotide length. Relevant information, concerning complex stability in the gas phase, was obtained only for larger non-covalent complexes
Bajin, ba Ndob Idensi. "Etude chimique et biologique d'Annonaceae gabonaises : Annona squamosa L. et Isolona hexaloba Engl. & Diels." Paris 11, 2008. http://www.theses.fr/2008PA114842.
Chemical and biological studies of two gabonese Annonaceae of medicinal and alimentary interest, Annona squamosa L. And Isolona hexaloba Engl. & Diels, was made. From the less polar fractions of Annona squamosa seeds extract, twenty acetogenins were obtained, four of them having an original structure : one bis-epoxyde compound, one bis-epoxyde with a double bond (type E) and two bearing an α,α'-dihydroxylated THF cycle and a double bond (type A). In order to verify its potential implication in atypical parkinsonism attributed to the consumption of Annonaceous acetogenins species, the fruit pulp of Annona squamosa was studied. MALDI-TOF mass spectrometry analysis of fractions obtained from the chloromethylenic extract allowed identification of 19 masses corresponding to acetogenins. Squamocin, was isolated. A quantitative study showed that one fruit, weighing 150 mg, contains about 1,6 mg of acetogenins with 0,2 mg of squamocin. Biological study of leaves, stems, and trunk bark of Isolona hexaloba, used in the treatment of malaria in Gabon, showed the antiparasitic potential of alkaloidic extracts of these drugs, with anti-malarial, leishmanicidal, and trypanocidal actvities. The qualitative analysis of these extracts by MALDI-TOF mass spectrometry revealed the presence of 32 masses corresponding to isoquinolic alkaloids measured with a good accuracy. An oxoaporphin, liriodenin, was isolated from the trunk bark alkaloid extract
Bodet, Pierre-Edouard. "Recherche de biomarqueurs glucidiques de mucopolysaccharidoses et étude de la physiopathologie." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLE001/document.
The identification of biomarkers remains one of the main challenges for analytical sciences and a major stake for clinical research. Glycosaminoglycans (GAGs) have been identified as potential biomarkers of mucopolysaccharidoses (MPS) belonging to rare genetic diseases with often a deadly issue. These pathologies are due to a deficiency in one of the enzymes responsible for GAGs catabolism. This enzymatic defect results in the accumulation of partially catabolized GAGs in organism and leads to neurodegeneration for the most severe forms of the disease. GAGs are complex polyanionic polysaccharides involved in numerous physiological processes in mammals. Their study remains a challenging task because of their high structural heterogeneity and their low biodisponibility, besides the lack of dedicated analytical tools. Our aim was to detect and quantify these compounds in biologic fluids such as urine and cerebrospinal fluid, and to elucidate their structures by mass spectrometry. This study focused on heparan sulfate (HS) oligosaccharides, as potential biomarkers of MPS featured by neurological manifestations (MPS I, IIIB and IIIC), and possibly responsible of lesions in the central nervous system. An experimental strategy allowing the extraction of HS oligosaccharides from biological fluids was implemented, thereby the structures of urinary heparan sulfate oligosaccharides were deciphered, leading to possible biomarkers candidates of MPS IIIB and IIIC. These compounds could be useful for diagnostic and patient follow-up that are currently lacking for the monitoring of therapeutic assays. In vitro exposition of different cerebral cell types to HS oligosaccharides was carried out to establish the relation between the structure of oligosaccharides and neuropathological effects. These studies highlighted several cellular processes that could be involved in neurodegeneration and constitute new therapeutic targets
Joly, Laure. "Couplage spectroscopie optique - spectrométrie de masse : propriétés optiques et photofragmentation de biomolécules." Thesis, Lyon 1, 2009. http://www.theses.fr/2009LYO10085.
This manuscript discusses optical properties and photofragmentation of gas phase biomolecules. These experiments are performed with a quadrupolar ion trap coupled to a UV-visible tunable laser. Molecules are isolated at the center of the trap, and irradiated by the laser beam. The most intense relaxation channel observed for multiply negatively charged ions is electron emission. This loss of one electron leads to radical anion formation. The first part of this manuscript is dedicated to the study of the mechanisms leading to the electron loss. Photodetachment experiments performed in Lyon were completed by photoelectron spectroscopy experiments performed in Karlsruhe (Pr. Kappes). The radical anion production has an important analytical potential. One of the main objectives of this work was to study the reactivity of this radical anion and to show the interest of radical fragmentation for the structural analysis of peptides. An other objective was to probe electronical properties of gas phase peptides and proteins. The electron detachment yield is recorded as a function of laser wavelength. We have determinated optical fingerprints for neutral, deprotonated and radical chromophores localized in the heart of proteins. These results are compared to computational methods (TD DFT)
Sabir-Bagag, Aïcha. "Photoionisation et spectrométrie de masse : un nouvel outil pour l'identification de biomolécules." Thesis, Evry-Val d'Essonne, 2008. http://www.theses.fr/2008EVRY0041/document.
My PhD’s work has been completely dedicated to develop new ionization source in mass spectrometry: the atmospheric pressure photoionization (APPI). This work is developed on two main areas. On the one hand, it aims to apply this method to new family of biomolecules. On the other hand, we report a comprehensive study on the ionization mechanisms in APPI. The first part of this manuscript offers a better understanding of the behaviour of the biological molecules under VUV radiation and atmospheric pressure. Indeed, we were able to say that polar and high molecular weight biomolecules could be easily photoionizable. Moreover, this work allows studying the effect of the medium (solvent) on the photoionization mechanism to be studied. It is possible to control the orientation of the observed reactions and to choose a particular type of molecular ion. We observed extensive and peculiar fragmentations which have never been detected with classical ionization techniques. The originality and innovative approach of this experience led us to transfer it to a UV beamline of the Synchrotron SOLEIL. Using an accordable source will certainly enhance the versatility of the ion source
Wisztorski, Maxence. "Développements en imagerie par spectrométrie de masse et applications aux modèles invertébrés." Lille 1, 2006. https://ori-nuxeo.univ-lille1.fr/nuxeo/site/esupversions/b2cd98ef-2445-48bc-9462-f547716f3776.
Douix, Suzie. "Caractérisation de perfluorocarbones (CₓFᵧ, PFCs) par spectrométrie de masse et spectroscopie VUV." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS523/document.
Perfluorocarbons compounds have both hydrophobic and lipophobic properties. They have been manufactured since the 1950s, and widely used in many industrial applications. However, they are persistent, bioaccumulative compounds with long atmospheric lifetimes. They are considered to be potent greenhouse gases, and are supposed to be mainly degraded by photolysis in the upper atmosphere. A work of physicochemical characterization of two perfluorinated compounds was realized on the PFOA and PFOS. They have been found to be the final compounds of degradation of the majority of perfluororinated compounds. VUV spectroscopy and mass spectrometry experiences have been undertaken to identify their relaxation pathways after photoactivation. A methodology based on the coupling of synchrotron radiation and mass spectrometry was developed to perform absolute cross section measurements and was apply to the compounds of interest. These measurements have been used to determine their photolysis rates and atmospheric lifetimes according to the altitude
Dadi, Hala. "Analyse par spectrométrie de masse des tubulines et de l'hormone de croissance." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS582.
The tubulins are proteins involved in cellular processes that are essential for cell life. The tubulins are polymodified at their C-terminal extremities. Different techniques have been used to characterize the polymodifications of tubulins. However, some challenges remain in the fine identification of some structures. In fact, mass spectrometry ion mobility can separate ions of the same m/z ratio depending on their conformations. In the first part of this thesis, an ion mobility mass spectrometry analysis allowed the separation of two synthetic peptides that mimic the structure of C-terminal peptides of biglycylated α-tubulins. In order to extrapolate this type of experiment to the C-terminal peptides purified from biological tubulins, we employed an analytical process to analyze these peptides from purified brain tubulins. Growth hormone (GH) is an anabolic hormone and a doping agent used by athletes. The availability of rhGH in the black-market has continuously increased because of doping in sports. The natural and the biosynthetic hGH have identical peptidic sequences. So far, the valid hGH anti-doping tests by the world antidoping agency are based on immunological recognition. However, Immunoassays have their own limitations. Therefore, the next generation analysis of GH has to be more specific and accurate. In the second part of this thesis, mass spectrometry coupled to reversed phase chromatography was used to find chemical differences between the pituitary hGH and the rhGH. The pituitary extracted hGH is glycosylated whereas the biotech product is sugar free. The present work represents an opening towards a novel methodology for a novel hGH anti-doping test
Barrere, Caroline. "Analyse de polymères synthétiques par résonance magnétique nucléaire et spectrométrie de masse." Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10061/document.
This thesis work deals with two main analytical aspects of PEO-b-PS amphiphilic block copolymers, their structural characterization and their quantitation in mixture, using NMR and mass spectrometry. In a first part, a novel approach was developed for the determination of copolymer weight average molecular weight by PGSE NMR. The issue of MALDI mass analysis of PEO homopolymers functionalized with a labile nitroxide end-group for the purpose of nitroxide mediated polymerization of the PS block was also addressed. A multidisciplinary approach involving NMR, mass spectrometry and theoretical calculation gave rise to an efficient derivatization strategy aimed at allowing intact PEO adducts to be generated by MALDI. In addition, requirement for impurity quantitation in polymer samples led to the development of a rapid and accurate method using PGSE NMR. This approach, based on the measurement of magnetic relaxation times during PGSE experiments to enable signal intensity renormalization, evidenced the issue of transverse relaxation time estimation in the case of coupled spin systems. A novel NMR pulse sequence was hence proposed and successfully applied for accurate measurement of transverse relaxation times in a model case of a two-spin coupled system
Barrere, Caroline. "Analyse de polymères synthétiques par résonance magnétique nucléaire et spectrométrie de masse." Electronic Thesis or Diss., Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10061.
This thesis work deals with two main analytical aspects of PEO-b-PS amphiphilic block copolymers, their structural characterization and their quantitation in mixture, using NMR and mass spectrometry. In a first part, a novel approach was developed for the determination of copolymer weight average molecular weight by PGSE NMR. The issue of MALDI mass analysis of PEO homopolymers functionalized with a labile nitroxide end-group for the purpose of nitroxide mediated polymerization of the PS block was also addressed. A multidisciplinary approach involving NMR, mass spectrometry and theoretical calculation gave rise to an efficient derivatization strategy aimed at allowing intact PEO adducts to be generated by MALDI. In addition, requirement for impurity quantitation in polymer samples led to the development of a rapid and accurate method using PGSE NMR. This approach, based on the measurement of magnetic relaxation times during PGSE experiments to enable signal intensity renormalization, evidenced the issue of transverse relaxation time estimation in the case of coupled spin systems. A novel NMR pulse sequence was hence proposed and successfully applied for accurate measurement of transverse relaxation times in a model case of a two-spin coupled system
Labastie, Pierre. "Molécules très excitées et petits agrégats métalliques : étude par spectroscopie et spectrométrie de masse." Lyon 1, 1987. http://www.theses.fr/1987LYO10065.
Hautreux, Mélanie. "Spectrométrie de masse de complexes moléculaires et macromoléculaires de cations alcalins et alcalino-terreux." Paris 11, 2002. http://www.theses.fr/2002PA112266.
The aim of this work is the study of the complexation of alkali and alkaline-earth metal cations with biologic molecules in the gaz phase. After a description of experimental methods used in this work we present results relative to the study of alkali cations and ammonium complexes with crown ethers formed by electrospray. One of the most important question in this field is to evaluate if the species observed in the mass spectra are representative of complexes formed in the solution phase. Some experiments of energy-resolved mass spectrometry permit to establish a relation between the internal energy laid on ions during ionization and their stability. These experiments led us to show that the relative intensities observed in mass spectra do not permit to establish directly a selectivity order of cations in solution. The structural study in LSl-MS/MS and in ESI-MS/MS of complexes of alkali cations and calcium with ionophorous compounds led us to consider their relative stability in the gas phase and to locate some sites of complexation. Then, we investigated the effect of basic organic compounds in the solution phase on the ionization of various proteins. Physicochemical characters of bases and the structure of macromolecules determine the charge states and the stability of proteins observed in electrospray mass spectra. These results were applied successfully to calmodulin/calcium complexes, the stability of these ionic species being reinforced by use of basic buffers
Rhourri-Frih, Boutayna. "Analyse, classification et caractérisation de résines d'origine végétale par chromatographie et spectrométrie de masse." Thesis, Orléans, 2009. http://www.theses.fr/2009ORLE2054/document.
The aim of this research was to analyze and classify 31 natural resins using different analytical tools (HPTLC, LC-UV, LC-ELSD, LC-MS, GC-MS and NMR) in order to verify the link between the chemical composition of resins and their botanic belongs. Natural resins are mostly composed from triterpens that is the reason why development of sensitive liquid chromatography method hyphenated to mass spectrometry detection was necessary. APPI and APCI were proved to be the most adequate sources of ionization for triterpens mass spectrometry analysis. Triterpens have low polarity index and contain number of isomers making their extraction and separation difficult in liquid chromatography. To improve their extraction and separation in their natural matrix, different parameters were considered. Finally, three triterpens derivatives were described for the first time in Manilkara bidentata resin and their bio-activity was tested on human skin cells cultures
Becker, Joël. "Etude et développement d’un spectromètre de masse et énergie : modélisation et optimisation de l’optique, réalisation du prototype." Paris 6, 2013. http://www.theses.fr/2013PA066262.
The objective of my work was to develop, implement and test a neutral mass spectrometer to study planetary exospheres, NIMEIS (Ion and Neutral Mass and Energy Imaging Spectrometer). The particles in the planetary exospheres are signatures of the interaction between the environment and the atmosphere or/and the planet's surface. For this purpose, an ion and neutral mass spectrometer, capable of determining the mass and energy of the particles in the exosphere was defined. A numerical model of the instrument is optimized in order to cover the requested instrumental performances. This numerical model has been then used to design, build and test the first prototype of NIMEIS. I also worked on the development of an ionization source, necessary for the operation of the neutral mass spectrometer. This original ionization source was based on the use of carbon nanotubes as electron emitters. We work in collaboration with a South Korean laboratory that provides us carbon nanotube emitters. Our tasks were to design, build and model device of extraction in the aim to optimize the principle of the electron extraction. I also worked on the definition and optimization of the numerical model of the instrument PICAM (Planetary Ion CAMera). PICAM is an ion mass spectrometer on the BepiColombo mission which will study Mercury’s exosphere. The originality of this instrument is to measure mass and energy as well as to provide an instantaneous image of an hemisphere. The goals of the numerical optimization was to start from the design of the instrument DION forthe Phobos-Grunt Mission (Vaisberg et al. 2010) and to increase as much as possible the geometrical factor in order to achieve the required performances in Mercury’s exosphere
Fournier, I. "Développements en Imagerie par Spectrométrie de Masse MALDI et Applications aux Problématiques Biologiques." Habilitation à diriger des recherches, Université des Sciences et Technologie de Lille - Lille I, 2005. http://tel.archives-ouvertes.fr/tel-00167305.
Cependant, afin d'augmenter encore la potentialité de cette technologie, des développements restent encore à effectuer. Les recherches menées ont donc plus particulièrement portées sur ces développements.
En particulier, la recherche et l'étude de nouvelles matrices plus adaptées à l'analyse directe de tissu en MALDI sont particulièrement importantes. Dans ce contexte, certaines matrices ioniques se sont révélées particulièrement adaptées aux tissus en permettant d'obtenir une plus grande intensité du signal, un plus grand nombre de composés détectés, de bonnes performances en mode négatif, une grande homogénéité de cristallisation, une grande stabilité sous vide et une faible ablation de matériel consécutivement à l'irradiation laser. Dans un autre aspect, le traitement préalable des tissus permet également une amélioration de la qualité spectrale et des performances d'études structurales en mode MS/MS. Se sont révélés particulièrement intéressants les traitements des tissus aux solvants organiques et les digestions enzymatiques et en particulier pour les tissus conservés en blocs de paraffine après fixation.
D'autre part l'étude de la répartition des ARNm au sein des tissus est un développement crucial afin d'obtenir des images de colocalisation transcriptome/protéome. Est proposé dans ce travail un nouveau concept permettant de réaliser ces images, basé sur une analyse indirecte des ARNm, au travers de l'utilisation d'un groupement photoclivable relié à un peptide marqueur de séquence connue qui sera détecté.
Enfin, l'ensemble de ces développements trouve de nombreuses applications dans le domaine de la biologie et notamment dans le cadre de pathologies tel que le cancer de l'ovaire.
Vervier, Kevin. "Méthodes d’apprentissage structuré pour la microbiologie : spectrométrie de masse et séquençage haut-débit." Thesis, Paris, ENMP, 2015. http://www.theses.fr/2015ENMP0081/document.
Using high-throughput technologies is changing scientific practices and landscape in microbiology. On one hand, mass spectrometry is already used in clinical microbiology laboratories. On the other hand, the last ten years dramatic progress in sequencing technologies allows cheap and fast characterization of microbial diversity in complex clinical samples. Consequently, the two technologies are approached in future diagnostics solutions. This thesis aims to play a part in new in vitro diagnostics (IVD) systems based on high-throughput technologies, like mass spectrometry or next generation sequencing, and their applications in microbiology.Because of the volume of data generated by these new technologies and the complexity of measured parameters, we develop innovative and versatile statistical learning methods for applications in IVD and microbiology. Statistical learning field is well-suited for tasks relying on high-dimensional raw data that can hardly be used by medical experts, like mass-spectrum classification or affecting a sequencing read to the right organism. Here, we propose to use additional known structures in order to improve quality of the answer. For instance, we convert a sequencing read (raw data) into a vector in a nucleotide composition space and use it as a structuredinput for machine learning approaches. We also add prior information related to the hierarchical structure that organizes the reachable micro-organisms (structured output)
Francoeur, Nancy. "Identification de nouveaux partenaires d'intéraction de TRPC3 et TRPC6 par spectrométrie de masse." Mémoire, Université de Sherbrooke, 2007. http://savoirs.usherbrooke.ca/handle/11143/3873.
Roy, Sylvie. "Couplage de la chromatographie liquide haute performance et de la spectrométrie de masse." Paris 5, 1989. http://www.theses.fr/1989PA05P035.
Viale, Jean-Paul. "Mesure des échanges gazeux par spectrométrie de masse en anesthésie et en réanimation." Lyon 1, 1988. http://www.theses.fr/1988LYO1H076.
Kernalléguen, Angéline. "Caractérisation et localisation des xénobiotiques dans les cheveux par spectrométrie de masse Maldi." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0754.
Hair analysis is now recognized as a relevant tool in the field of toxicology. It provides a precise history of an individual’s exposure to drugs, whether it is a punctual or repeated consumption.Matrix-Assisted Laser Desorption/Ionization (MALDI) has many advantages over conventional techniques: the amount of hair needed is reduced, the sample preparation is simplified and the images are acquired with high spatial resolution (~ 100 μm).MALDI (MALDI-MSn) imaging allowed us to characterize and map the evolution of drugs amounts along the hair with very spatial resolution avoiding long and complex pre-sample preparation.MALDI coupled to Microaarays for Mass Spectrometry (MAMS) allowed us to develop a method for semi-quantitation of cocaine, benzoylecgonine, ecgonine methyl ester and cocaethylene using 1 mg of hair and 2 hours of extraction; the results are well correlated with a validated quantification method. This method is relevant when urgent results are required.In total, the development of these two applications demonstrates the relevance of MALDI mass spectrometry in the toxicological analysis of hair. The prospects are to improve these protocols in order to transpose them routinely and to develop large screening methods by MALDI mass spectrometry
Lafarge, Patricia. "Couplage chromatographie en phase gazeuse-spectrométrie de masse : principe, réalisation, pratique et intérêt analytique." Paris 5, 1988. http://www.theses.fr/1988PA05P048.
Martelet, Armelle. "Détection et identification de bactéries dans des matrices complexes par amplification phagique et spectrométrie de masse." Paris 6, 2013. http://www.theses.fr/2013PA066577.
Mériaux, Céline. "Imagerie du système nerveux central par spectrométrie de masse MALDI." Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10059/document.
In recent years, MALDI mass spectrometric imaging has proved to be a powerful tool for biomarker research. This technology allows the analysis of a wide range of endogenous and exogenous compounds in tissue sections. Many developments need to be undertaken to improve the detection of molecules. The sample preparation, including chemical treatment and deposition of the matrix, is dependent on the tissue and molecules of interest and influences the quality of spectra and images. In addition, the bioinformatics tools such as multivariate analysis provide informations on the markers according to phenotypes. These steps are crucial for imaging applications in the field of biology. First of all, we focused on the development of new matrices suitable for MALDI imaging such as ionic matrices. Secondly, these developments have been applied to the invertebrate model, the medicinal leech, at embryonic and adult stages, to compare the biological mechanisms involved in the establishment of the central nervous system and nerve regeneration after injury of this system. Finally, studies of neurological damage have been undertaken to understand the key factors involved in the balance regeneration/degeneration. Thus, studies of human hippocampi samples have revealed the existence of proteins associated with a particular distribution corresponding to layers of neurons abnormally present in the hippocampus of epileptic patients
Gagez, Anne-Laure. "Applications de la spectrométrie de masse aux études du métabolisme et à la pharmacodynamie des immunosuppresseurs." Limoges, 2010. https://aurore.unilim.fr/theses/nxfile/default/dfa11d6e-4152-4c77-926f-fb7171b51248/blobholder:0/2010LIMO310L.pdf.
This work is concerned with the study of pharmacodynamics by mass spectrometry, which aims to characterize biochemical and physiological effects of drugs on the organism: drug transportation, target fixation, biotransformation, and excretion. The degree of formation of covalent adducts between mycophenolic acid acyl-glucuronide (AcMPAG) and human serum albumin, inosin monophosphate deshydrogenase or hepatic urindin 5’-diphosphate glucuronosyltranferases (UGT) were estimated. Tolmetin acyl-glucuronide (unavailable product), should be used as positive control to recreate the experimental conditions of Ding et al. In 1993, to confirm our results with AcMPAG. Determination of glucuronidation activities in vitro (phenotyping) of 6 major UGTs implicated in drug detoxification was determined by single liquid chromatography-tandem mass spectrometry (LC-MS/MS). Priliminary results (kinetics and inhibition) for the quantification of phosphatase activity of calcineurin by LC-MS/MS were obtained. Further experiments are needed for a reproducible method to be used in routine laboratory practise. This may serve as an indicator for calcineurin activity in the context of iatrogenic immunosuppressant. Results from the final logistic regression model identified certain natural peptides that could successfully discriminate between AR and non-AR [p17 (Odds ratio (OR) = 62. 2; 95% confidence interval (CI) (5. 9-650. 4); p = 0. 0006) and p24 (OR = 22. 9; 95% CI (2. 5-212. 2); p = 0. 0058)]; CAN1 and non-CAN1 [p 17 (OR = 12. 4; 95% CI (2. 6-60. 7); p = 0. 0018) and p35 (OR = 0. 04; 95% CI (0. 005-0. 4); p = 0. 0065)]; and ST and non-ST [p4 (OR = 7. 7; 95% CI (2. 3-25. 7); p = 0. 0009)]
Terrier, Péran. "Caractérisation de polymères et étude de complexes non covalents ADN-polymère par spectrométrie de masse." Evry-Val d'Essonne, 2006. http://www.theses.fr/2006EVRY0042.
This PhD work is composed of two parts, dealing with the characterisation of polymers and the study of DNA-polymer non-covalent complexes using mass spectrometry. The polymers under study are presently tested as gene therapy vectors. The first part is dedicated to the analysis of poly(oxyethylene) and poly(oxypropylene) block copolymers. The determination of their global composition (number of repeat units) and the detection of by-products was achieved using MALDI-MS. The influence of experimental parameters was investigated. The characterisation of the polymer sequences (order of the repeat units within the chains) was achieved thanks to Electrospray-MS/MS. The second part deals with the study of non-covalent complexes involving DNA and cationic polymers (basic peptides, polyamines). We managed to obtain these complexes in the gas phase using Electrospray and MALDI ionizations. In both cases, the relevance of the detected ions in MS mode was discussed, and interactions involved in the complexes were probed by MS/MS mode
Guy, Philippe. "Utilisation de la spectrométrie de masse pour l'étude structurale des protéines." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10085.
Génin, Eric. "Spectrométrie de masse et chimie des insectes : comparaisons intraspécifiques chez Bombus hypnorum et Locusta migratoria cinerascens." Paris 11, 1987. http://www.theses.fr/1987PA112296.
Oliva, Mizar Francesca. "Analyse biochimique et par spectrométrie de masse d'un complexe ribonucléoprotéique d'export du VIH-1." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAV029/document.
An important step in the life cycle of human immunodeficiency virus (HIV) is the nuclear export of incompletely spliced viral transcripts, including the replicated viral RNA genome. This process is mediated by the viral RNA-binding protein Rev. In the nucleus, Rev recognizes unspliced and partially spliced viral transcripts by multimerizing on a 350-nucleotide intron sequence, the Rev-response element (RRE). Rev then recruits the host cell export factor CRM1 and the small GTPase Ran to form the RRE/Rev/CRM1/Ran export complex. Knowledge of the 3D architecture of this ribonucleoprotein complex would provide important insights into how unspliced viral RNA export is achieved. However, the molecular details of this complex are poorly understood. In particular, the stoichiometry of Rev and CRM1 molecules bound to the RRE is under debate.My Ph.D. project aims to investigate the architecture of the RRE/Rev/CRM1/Ran complex. As part of this work, I used biochemical and cell-based assays to characterize the interactions between CRM1 and Rev and between Rev and the RRE. The majority of my efforts focused on investigating these interactions by native mass spectrometry (MS), a powerful method for determining the stoichiometry of macromolecular complexes. I set up protocols for the large-scale preparation of a 66-nucleotide RRE fragment (IIABC) bearing a high-affinity Rev binding site, and adapted these for compatibility with native MS analysis. Because Rev tends to aggregate and precipitate in solution, I engineered a mutant form of Rev (Rev*) to overcome this problem. Analysis of IIABC/Rev* complexes by native gel electrophoresis confirms multimerization of Rev on the RNA. After extensive optimization, I obtained high-quality native MS spectra of these complexes, revealing that IIABC binds up to 6 Rev* monomers. Furthermore, I reconstituted a 4-species complex, IIABC/Rev*/CRM1/Ran, and succeeded in determining its mass and stoichiometry by native MS – a technically challenging task. Additional efforts at analyzing the intact RRE and complexes with wild-type Rev have also yielded informative spectra, while analysis of the intact RRE/Rev/CRM1/Ran holo-complex has had more limited success. These results illustrate the strengths and limitations of native mass spectrometry and its potential for future development as a tool for analyzing ribonucleoprotein complexes