Dissertationen zum Thema „Spectrométrie de Masse à Mobilité Ionique“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Machen Sie sich mit Top-50 Dissertationen für die Forschung zum Thema "Spectrométrie de Masse à Mobilité Ionique" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Sehen Sie die Dissertationen für verschiedene Spezialgebieten durch und erstellen Sie Ihre Bibliographie auf korrekte Weise.
Domalain, Virginie. „Différenciation de stéréoisomères par couplage, spectrométrie de masse et spectrométrie de mobilité ionique“. Rouen, 2014. http://www.theses.fr/2014ROUES023.
Der volle Inhalt der QuelleThis 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
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.
Der volle Inhalt der QuelleLasso 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)
Maire, Florian. „Étude des dendrimères polyamidoamines par spectrométrie de masse et mobilité ionique“. Rouen, 2010. http://www.theses.fr/2010ROUES018.
Der volle Inhalt der QuelleIn 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
Ziemianin, Anna. „Apport de la mobilité ionique en spectrométrie de masse pour les études enzymatiques“. Rouen, 2011. http://www.theses.fr/2011ROUES039.
Der volle Inhalt der QuelleIn the first part we reported MS based evaluation of potential new AChEI with the determination of their inhibitory activity. As compared to the Ellman’s method that uses the substrate analog acetylthiocholine, using the ElectroSpray Ionization Quadrupolar Ion Trap Mass Spectrometry (ESI-IT-MS) consists in monitoring the conversion ratio of a low concentration of the natural substrate - acetylcholine to choline. We present here the inhibition effect of the series of huprines of acetylcholinesterase (AChE) on the hydrolysis of acetylcholine. The Michaelis - Menten constants (KM), inhibitory constants (KI) were examined as well as the IC50 to allow classifying the series of huprines derivatives by inhibition potency. Our results demonstrate that these drugs are very potent AChE inhibitors. In the second part of my thesis the outstanding analytical performances of ion mobility mass spectrometry (SYNAPT G2 HDMS, Waters) were applied to study high molecular weight non-covalent interactions in bio-complexes. The application of this technique (IM-MS) to the detection of intact protein complexes was developed on the tetrameric protein alcohol dehydrogenase (ADH) (148kDa) and the complex ADH - NAD+ and its inhibitors
Mendes, Siqueira Anna Luiza. „Apport de la spectrométrie de mobilité ionique couplée à la spectrométrie de masse pour la caractérisation de produits pétroliers formulés“. Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR044.
Der volle Inhalt der QuelleNowadays, formulated petroleum products such as fuels and lubricants must respond toprecise technical requirements to ensure the best performance, reliability and longevity ofengines while limiting the emission of pollutants. This thesis work focused on the development of analytical methodologies for the identification of polymeric additives in diesel fuels and the characterization of polyalphaolefins. The additive analysis was performed by coupling of liquid chromatography, ion mobility spectrometry and mass spectrometry (LC-IMS-MS), the ionization was performed by electrospray (ESI). After adjusting the experimental parameters, all additives were identified in the diesel fuel without sample preparation. The coupling of liquid chromatography at the critical condition chromatography (LCCC) with mass spectrometry was also evaluated in order to improve the separation of additives from the diesel fuel matrix. The characterization of polyalphaolefins (PAO) was carried out by IMS-MS with ASAP (atmospheric solids analysis probe) or APPI (atmospheric pressure photoionization) sources. With ASAP, in addition to pyrolysis ions, intact species were detected for low PAO grades. In the case of high PAO grades, only pyrolytic fragments were detected, yet it was possible to identify the alphaolefins used to produce the PAOs. In APPI, the use of halogenated solvents and toluene, allowed to observe intact species for high PAO grades through the formation of halogenated adducts. With IMS-MS coupling polyalphaolefins were differentiated the by the study of drift times and full width at half maximum
Bécard, Stéphanie. „Développements méthodologiques en spectrométrie de masse et en mobilité ionique pour l'étude d'assemblages supramoléculaires en biologie“. Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAF036/document.
Der volle Inhalt der QuelleThe aim of this thesis was the development of different supramolecular approaches, like MS and IM-MS, to characterize precisely protein/ligand interaction and to analyze complex mixtures of proteins. Understanding of supramolecular MS instruments and instrumental and methodological optimizations were allowed the development of MS and IM-MS to characterize very high mass supramolecular assembly. Thus, we were able to follow by kinetic the formation of protein/ligand interaction as well as associated conformational modifications, showing the interest of IM-MS coupling in pharmaceutical research. Furthermore, this work deals with the study of high mass complexes and assessment of IM-MS to obtain structural information on these complexes. As a consequence, we have pushed away some limits of MS allowing the use of this technique in structural biology
Hupin, Sébastien. „Caractérisation d’auto-assemblages de polyoxométallates hybrides organiques-inorganiques par spectrométrie de mobilité ionique couplée à la spectrométrie de masse“. Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR062.
Der volle Inhalt der QuellePolyoxometalates (POM) are anionic compounds formed by the assembly of metal oxide polyhedra {MOy}, (with M, MoVI or WVI) linked together by oxygen atoms. POM thus form a remarkable class of nanometric inorganic metal oxide clusters, with a wide variety of charges and structures. It is possible to form hybrid systems including the inorganic part of the POM and a grafted organic part, allowing new functionalities to be added to the POM, such as selfassembly. We have dedicated this thesis work to the characterization of standards, hybrid and self-assembled POM systems by mass spectrometry coupled to ion mobility spectrometry (IMS-MS). A first experimental approach using drift tube ion mobility spectrometry (DTIMS) allowed us to determine the collision cross sections (CCS) of standard POM in helium and nitrogen. The CCS of the POM standards then allowed us to calibrate an IMS cell of a Travelling Wave ion mobility instrument (TWIMS). The analysis by IMS-MS of organic-inorganic hybrid POMs alone or in the presence of transition metal cations revealed the presence of self-assembled triangular [POM3·cation3], square [POM4·cation4] or pentagonal [POM5·cation5] systems with different charge states. CCS values of these self-assemblies was estimated from the calibration of the TWIMS cell. Using a theoretical approach, we modelled several standard POM structures with and without tetrabutylammonium counterion (TBA+) using density functional theory (DFT). The optimized structures were used to determine theoretical CCS using the trajectory method of the MOBCAL software, in which we incorporated molybdenum and tungsten atoms for which we optimized new Lennard Jones potential parameters. The correspondence of experimental and theoretical CCS of standard POM structures offers new possibilities for structural attribution of self-assembled hybrid POM by coordination in the presence of metal cations
Farenc, Mathilde. „Apports de la mobilité ionique couplée à la spectrométrie de masse pour l’analyse des matrices complexes“. Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR007/document.
Der volle Inhalt der QuellePetroleum is a highly complex mixture that needs to be refined in order to be commercialized. The petroleum fractions have various compositions from gasoline to petroleum coke. Naphtha distillation cut gives olefins by steam cracking which are polymerised using metallocene catalysts to produce polyolefins. This thesis work focused on the characterisation of vacuum gas oils, polyolefins and metallocene catalysts to better understand and optimized refining processes. A comparison of atmospheric pressure ionisation sources was realised for the characterisation of vacuum gas oils by ion mobility–mass spectrometry (IMMS). Electrospray (ESI+) source allows to selectively analyse the basic nitrogen containing species. The ASAP and APPI (atmospheric pressure photoionisation) sources allows to identify sulphur containing compounds like benzothiophenes. Based on the IMMS data, a new indicator based on the full width at half maximum (FWHM) of ion mobility peaks was developed to obtain isomeric information without any identification of the species. Polymers were also analysed using the ASAP source. In particular, polypropylene (PP) and polyethylene (PE) were analysed by ASAP-IMMS and allow us to identify the oxidized species obtained by atmospheric pressure pyrolysis. The relative abundance of these species and their drift time were significantly different between the different samples and notably between isotactic PP and atactic PP. Finally, a new method based on the ASAP source was developed to analyse air sensitive compounds like metallocene used for polyolefin polymerisation
Becard, Stéphanie. „Développements méthodologiques en spectrométrie de masse et en mobilité ionique pour l'étude d'assemblages supramoléculaires en biologie“. Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00832488.
Der volle Inhalt der QuelleAlbrieux, Florian. „Etude conformationnelle de peptides et protéines par mesure de mobilité ionique couplée à la spectrométrie de masse“. Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00594601.
Der volle Inhalt der QuelleSimon, Anne-Laure. „Couplage de la spectrométrie de mobilité ionique et de la spectroscopie optique : études conformationnelles en phase gazeuse“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1128/document.
Der volle Inhalt der QuelleThis thesis deals with the development of a new instrument coupling mass spectrometry, ion mobility spectrometry and laser spectroscopy. The aim is to perform structural analysis on biomolecular systems.The first part of this thesis focuses on the construction, the development and the optimization of the set-up. The main point was to determine the features of the set-up (resolution, working frequency) by series of tests with model systems.In a second phase, we did conformer resolved action spectroscopy. We studied the relation between the conformation and the optical properties of one system by measuring photo- electron detachment on different selected conformers. In the framework of action spectroscopy we used the new capacity of the set-up to perform cis-trans photo-isomerization on non-covalent complexes. We showed with this example interest of the use of this instrument to measure photo-isomerization action spectra. We finally showed the possibility to perform conformer resolved action spectroscopy measurements based on Förster Resonance Energy Transfer (FRET) in the gas phase
Poyer, Salomé. „Développement de méthodes d'analyse par spectrométrie de masse à mobilité ionique pour l'identification des analogues de saxitoxine“. Rouen, 2015. http://www.theses.fr/2015ROUES053.
Der volle Inhalt der QuelleThis thesis work focused on the separation and identification of saxitoxin analogues, natural neurotoxic compounds. Modern separation techniques such as hydrophilic interaction liquid chromatography (HILIC) and ion mobility spectrometry (IMS) coupled to mass spectrometry (MS) were developed for the analysis of saxitoxins. HILIC-MS and IMS-MS coupling were developed, showing a complementary for separation of the various saxitoxin analogues. HILIC-IMS-MS coupling was then optimized and allowed the fast separation of the toxin analogues. The HILIC-IMS-MS coupling was also repeatable when complex mixtures were injected, although it was less sensitive than with the coupling of HILIC with a triple quadrupole instrument operated in targeted mode. IMS application to saxitoxins also permitted to determinate the collision cross section values of each analogue. The calculation of theoretical structures permitted the determination of theoretical collision cross sections that were correlated to experimental values and allowed the access of gaseous phase conformation. Saxitoxin analogues characterization was carried out by tandem mass spectrometry of [M+H]+, [M+Li]+, [M+Na]+, [M+K]+ and [M−H]− species. The different product ions gave information about stability of chemical functions depending on the different species studied
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.
Der volle Inhalt der QuelleThe 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
Hernandez, Alba Oscar. „Mecanisme de fragmentation des peptides en spectrométrie de masse : couplages de techniques de caractérisation structurale“. Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112421/document.
Der volle Inhalt der QuelleTandem mass spectrometry is a versatile analytical technique, used in particular in the field of proteomics to derive peptide sequence. This thesis aims to contribute to the development of integrated approaches to mass spectrometry to provide structural information on molecular ions, which can either be reaction intermediates or reaction products. The fragmentation of protonated peptides is induced by multiple collisions with rare gas atoms (CID). Multiple fragments are observed and the peptide sequence is derived from the measurement of the mass difference between two consecutive analogous ions. Fragmentation mechanisms of the protonated peptides under CID conditions constitute an intense research field. In the frame of this PhD thesis, mass spectrometry and infrared spectroscopy were coupled to characterize the fragment ions (an and bn) peptides. Several infrared signatures were found in the 1000-2000 and 3000-3800 cm-1 spectral ranges characteristic of different structural motifs. In the case of the an ions, these IR signatures provide evidence of the permutation of the sequence of the peptide chain. In the case of the middle size bn ions, the formation of a macrocyclic structure relies on the specific formation of an ion-molecule complex with NH3, whose structure has been characterized by IR spectroscopy.The ultimate objective of this thesis was to develop a multimodal approach based on a single mass spectrometer, which incorporates ion mobility spectrometry and infrared spectroscopy in order to characterize the structure of mobility- and mass-selected molecular ions. The ion mobility technique used is the "Differential Ion Mobility spectrometry" (DIMS). Peptide fragment ions could not be studied using this new set-up. We chose to study the separation and characterization of cationized monosaccharides with Li+, Na+ or K+. In the case of lithiated complexes, the spectroscopic and ion mobility data are consistent with the low energy structures predicted by theory, allowing in particular the interpretation of an IR specific signature characteristic of some Li+ complexes of glucose anomers
Piccolo, Stefano. „Biophysical characterization of aptamer-ligand interactions by native mass spectrometry“. Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0276.
Der volle Inhalt der QuelleAptamers are single-stranded nucleic acids capable to bind selectively to a ligand or to a family of molecules. Aptamers are the sensing part of riboswitches, which are regulatory segments of messenger RNA involved in gene expression. Aptamers are also promising artificial probes, sensors and stimuli-responsive elements. In the development of aptamer-based technology, it is crucial to understand how binding is occurring, to quantify affinities, and ligand-induced conformational changes. The objective of this thesis is to explore the applicability of native IM-MS to DNA and RNA aptamers to quantify binding and to detect conformational change upon binding.In the first part, we evaluated the quantitative determination of equilibrium dissociation constants (KD) by mass spectrometry (MS), and the necessity of including a correction for relative response factors of free and bound aptamers. We compared isothermal titration calorimetry and MS titrations to validate the quantifications. Two RNA aptamers were taken as models: the malachite green aptamer, extensively studied by ITC, and the riboflavin mononucleotide aptamer, a case of Mg2+-dependent ligand binding. We observed that typical volatile electrolytes ammonium acetate and trimethyl ammonium acetate are suitable to study RNA aptamer binding, and that comparable KD values are obtained from ITC and native MS. The neomycin and tobramycin RNA aptamers were chosen to test the limit of detection of native MS. We found that native MS is appropriate to determine KD values in the range from 50 nM to 30 µM. The relative response factor correction was relatively modest in all cases, suggesting that the ligand binding is not associated to a significant conformational difference upon ionization. For these aptamers, we conclude that assuming equal response factors is acceptable.In the second part, we evaluated whether the aptamers’ “adaptive binding” mechanism can be revealed by ion mobility spectrometry (IMS). To this aim, in addition to the systems listed above we studied the tetracycline RNA aptamer and a series of cocaine-binding DNA aptamers, for which the conformational change upon binding is reported in literature. For all aptamers except the tetracycline aptamer, we did not observe a significant difference in the shape of the gas-phase structure upon ligand or Mg2+ binding. However, a significant change was observed in tetracycline RNA aptamer’s ion mobilities, at biologically relevant concentration of Mg2+ (100 µM), and we found that Mg2+ is essential for ligand binding, in agreement with previous solution studies. For the cocaine-binding DNA aptamer series, although we observed similar compactness for the free and bound aptamers in soft pre-IMS conditions, a conformational extension occurs at high pre-IMS activation, best revealed by charge state 7-, suggesting gas-phase rearrangements. To better investigate whether the energetics of these rearrangements depend on pre-folding or on ligand binding, we modified the sequences with dA overhangs, to compare systems with similar numbers of degrees of freedom without altering the core structure. We also propose new ways of presenting the data, adapted to the cases where ligand dissociation, declustering and unfolding occur at similar voltages. The gradual increase of the pre-IMS collisional activation revealed that the unfolding energetics is correlated with the base pairs content, suggesting that base pairs are conserved in the gas-phase structures. We also found that ligand is lost at lower energies than unfolding.In summary, gas-phase compaction occur for both the free aptamers and bound aptamers, and memories of the solution-phase structures can only be revealed in some particular cases. However, the compaction towards similar shapes might constitute an advantage for the quantification, because molecular systems of similar shapes have similar electrospray responses. Consequently, native MS provides reliable estimations of KD values
Stojko, Johann. „Nouvelles méthodologies en spectrométrie de masse native et mobilité ionique pour la caractérisation structurale de macrobiomolécules et de leurs complexes associés“. Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAF003/document.
Der volle Inhalt der QuelleThis PhD thesis aims at developing methods in native mass spectrometry (MS) combined with ion mobility (IM-MS) to characterize protein-ligand complexes and large protein assemblies. Fine-tuning of instrumental settings allowed expanding the scope of these approaches in structural biology. Real-time monitoring of protein-ligand complexes by native MS and IM-MS enabled to screen their binding properties while depicting subtle conformational changes induced upon binding. Applying these methods to refractory multi-protein complexes provided insights about their topology, making structural modeling easier. Finally, benefits from high-resolution native MS were highlighted through the characterization of heterogeneous systems, including monoclonal antibodies and their drug conjugates. Here, these developments enable to push some technical limits one step forward, increasing the potential of native MS and IM-MS both in academic research and pharmaceutical industry
Ballivian, Renaud. „Étude de complexes non-covalents et de polymères organiques par couplage entre la spectrométrie de masse et la mobilité ionique“. Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10219.
Der volle Inhalt der QuelleKnowing the structure of non-covalent complexes is essential to understand many biological processes. The first step is the characterization of the interactions leading to the adoption of a functional tridimensional structure by a multimeric assembly. The second step consists of underlining the structural modifications induced by the complexation, and their influence on the system’s function. The Ion Mobility/Mass Spectrometry (IM/MS) is a gas-phase method that is used to separate ions according to their geometry and their masse-to-charge ratio. IM/MS also provides insights on their intrinsic properties, by measuring their collision cross sections. Using this method, we have studied the structure of three different non-covalent complexes: the aggregation of tannins on the human salivary protein IB-5, the fixation of a small ligand (Ac2KAA) on vancomycin, and the complexation between metallic cations and poly-lactid polymers. The evolution of the collision cross-sections as a function of the size of the system or the complexation state clearly shows structural transitions. Moreover, combined with molecular modeling or laser spectroscopy, the IM/MS technique reveals to be a powerful tool to characterize the relevant interactions in such systems. This work proves that IM/MS, besides a powerful analytical aspect, can also be used in global studies that involve several structural methods to resolve the structure of large multimeric assemblies
Poully, Jean Christophe. „Spectroscopie IR et spectrométrie de mobilité ionique appliquées aux structures de systèmes chargés isolés d'intérêt pharmaceutique“. Phd thesis, Université Paris-Nord - Paris XIII, 2009. http://tel.archives-ouvertes.fr/tel-00465057.
Der volle Inhalt der QuelleChendo, Christophe. „Approche multidimensionnelle en spectrométrie de masse MALDI pour la caractérisation des polymères synthétiques“. Electronic Thesis or Diss., Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4759.
Der volle Inhalt der QuelleThis thesis manuscript describes methodological developments in MALDI-MS to characterize synthetic polymers, as well as associated fundamental studies carried out to rationalize unexpected results, allowing new insights in the MALDI process. Studied samples were synthesized by controlled radical polymerization and contained fragile end-groups that do not survive the ionization step. A multidimensional approach, combining high resolution mass spectrometry (MS and MS/MS) with ion mobility spectrometry, allowed a full characterization of in-source newly formed terminations in the case of polystyrene. For poly(4-vinylpyridine), a more specific experimental protocol was required to overcome the propensity of monomeric units to interact with matrix molecules. These strong interactions were revealed by P4VP/matrix complexes in which the type of bonds (covalent vs non covalent) changes with the MALDI source pressure. Using a source operated at quite high pressure, a reactive MALDI phenomenon was evidenced to generate a new P4VP species in which one matrix molecule was incorporated in the chain end. A model involving a radical coupling process was proposed to account for the formation of these covalent adducts. The high density of the MALDI plume in such "high pressure" source would also be responsible for the unexpected formation of doubly charged species for small synthetic polymers (Mn < 5 kDa). These results are consistent with charge transfers in the gas phase as the process for cation adduction of synthetic polymers in MALDI
Poully, Jean-Christophe. „Spectroscopie infra-rouge et spectrométrie de mobilité ionique appliquées aux structures de systèmes moléculaires chargés isolés d'intérêt pharmaceutique“. Paris 13, 2009. http://www.theses.fr/2009PA132024.
Der volle Inhalt der QuelleStructural properties and noncovalent interactions within biologically relevant molecular systems are crucial for their activity. They are especially important for the specific binding of drugs on receptors in living organisms. Besides, studying molecules in the gas phase allows measuring their intrinsic properties because of the absence of solvent effects. Precise information can then be extracted from the comparison between experimental data and state-of-the-art quantum chemistry calculations. Our research group aims to describe the structural changes occurring within peptides, oligonucleotides and pharmaceutically relevant complexes: we compare results from simulations and two complementary experimental techniques, IRMPD spectroscopy and ion mobility spectrometry. In this PhD thesis, I have tested for the first time the performances of a QM/MM method for the simulation of the IR spectra of isolated biomolecular systems. It allowed me to simulate the IR spectrum of amyloid β-protein strands containing more than 250 atoms. We found that the solvent in which these strands are diluted has a big influence on their gas-phase secondary structure: in the case of polar solvents, globular ones dominate, whereas a weak dielectric constant tends to favor helical structures. The structural changes upon receptor binding on vancomycin, a glycopeptide antibiotic, have also been studied. The receptor binding site in the protonated complexes is not the pocket which can be seen in X-ray scattering data, but the specific interactions responsible for the high binding constant of the complex in solution remains intact in the deprotonated species
Ollivier, Simon. „Exploration of high-resolution ion mobility-mass spectrometry for structural glycosciences“. Electronic Thesis or Diss., Nantes Université, 2022. http://www.theses.fr/2022NANU4069.
Der volle Inhalt der QuelleThe inherent complexity of carbohydrates remains a challenge for analytical sciences. No single method is currently able to fully resolve the various isomerisms present within the subunits and in glycosidic bonds, although these are determining structural features of carbohydrates. Mass spectrometry (MS) alone is blind to many cases of isomerism, and thus gives incomplete information for carbohydrates. Over the last ten years, the coupling of ion mobility spectrometry (IMS) with MS has kept gaining momentum. In fact, IMS is sensitive to the gasphase conformations of molecules and thus, to (stereo)isomerisms. In that context, this PhD work explores the potential of high-resolution IMS approaches for structural glycosciences. The state-of-the-art Cyclic IMS (cIMS) geometry, which affords fine gas-phase manipulations of ions, is studied. In a first part of our work, we demonstrate through a series of case studies that cIMS can resolve the various cases of isomerism found in carbohydrates. Based on these findings, we then endeavor to develop means to characterize the fine structure of oligosaccharides using multistage IMS. These developments notably include a targeted sequencing strategy and an untargeted IMS-based approach relying on molecular networks. In the last part, we couple cIMS with size exclusion chromatography with the aim to work directly on polysaccharides in the hundred-kilodalton range. Altogether, our results emphasize the potential of high-resolution IM-MS to settle as a pivotal method in structural glycosciences, and open the way to the study of larger if not intact polysaccharide structures
Botzanowski, Thomas. „Nouvelles méthodologies en spectrométrie de masse native et mobilité ionique pour la caractérisation structurale de protéines d'intérêt thérapeutique et de complexes multiprotéiques“. Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF010.
Der volle Inhalt der QuelleThis PhD work focuses on developments in native mass spectrometry and ion mobility methods for the structural characterization of therapeutic proteins and multiprotein complexes. First, careful optimizations of sample preparation and analytical conditions allowed the characterization of membrane proteins, which are hydrophobic proteins difficult to analyze by MS approaches in detergent environment. Then, a new ion mobility-based activation approach called Collision Induced Unfolding has been set up and evaluated. CIU allowed extensive and original conformational characterization of several therapeutic monoclonal antibody formats. Finally, native MS and ion mobility techniques were used for the characterization of heterogeneous multiprotein complexes depicting their benefit when combined to other biophysical techniques for the structural characterization of multiprotein complexes
Chendo, Christophe. „Approche multidimensionnelle en spectrométrie de masse MALDI pour la caractérisation des polymères synthétiques“. Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4759.
Der volle Inhalt der QuelleThis thesis manuscript describes methodological developments in MALDI-MS to characterize synthetic polymers, as well as associated fundamental studies carried out to rationalize unexpected results, allowing new insights in the MALDI process. Studied samples were synthesized by controlled radical polymerization and contained fragile end-groups that do not survive the ionization step. A multidimensional approach, combining high resolution mass spectrometry (MS and MS/MS) with ion mobility spectrometry, allowed a full characterization of in-source newly formed terminations in the case of polystyrene. For poly(4-vinylpyridine), a more specific experimental protocol was required to overcome the propensity of monomeric units to interact with matrix molecules. These strong interactions were revealed by P4VP/matrix complexes in which the type of bonds (covalent vs non covalent) changes with the MALDI source pressure. Using a source operated at quite high pressure, a reactive MALDI phenomenon was evidenced to generate a new P4VP species in which one matrix molecule was incorporated in the chain end. A model involving a radical coupling process was proposed to account for the formation of these covalent adducts. The high density of the MALDI plume in such "high pressure" source would also be responsible for the unexpected formation of doubly charged species for small synthetic polymers (Mn < 5 kDa). These results are consistent with charge transfers in the gas phase as the process for cation adduction of synthetic polymers in MALDI
Bouakil, Mathilde. „Étude de la conformation et de la dynamique conformationnelle de molécules biologiques en phase gazeuse“. Thesis, Lyon, 2020. http://www.theses.fr/2020LYSE1145.
Der volle Inhalt der QuelleProtein functions in living organism are governed by their 3D structure. This thesis focuses on the characterization of protein conformation and conformational dynamics by means of mass spectrometry, and participates to the development of tools for structural biology. Mass spectrometry coupled to time resolved optical spectroscopy can set light on mechanisms associated with conformational dynamics: photon absorption, electronic relaxation, photo-induced charge transfer, etc. Experimental approaches combining mass spectrometry, optics and molecular biology (protein expression, gel electrophoresis, circular dichroism, etc.) will be presented in the first section of this manuscript. This thesis work was initiated by the study of the photo-induced activation of the chromophores which were used, at ILM, for action-FRET and more generally for the exploration of the proteins structure. The mechanisms of photon absorption and non-radiative relaxation were studied for chromophores grafted on multiple peptides. We then probed the photo-induced intramolecular charge transfer and associated conformational dynamics in series of small peptides in order to understand the influence of the system size and composition on its structural dynamics. The latter experiment required the implementation of a two-color pump-probe setup. Finally, we used ion mobility spectrometry to probe and investigate the conformational space and dynamics of the PUMA peptide, ubiquitous in mammalian organisms and associated to the regulation of apoptosis
Rabin, Clemence. „Investigation of RNA kissing complexes by native electrospray mass spectrometry : magnesium binding and ion mobility“. Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0892/document.
Der volle Inhalt der QuelleBesides being the molecular intermediate between DNA and proteins, RNA can have many other functions such as gene regulation (riboswitches), gene expression (mRNA and tRNA) or catalysis (ribozymes). RNA function is linked to its structure and its folding dynamics. Cations such as magnesium bind to RNA and are in some instances essential for proper folding and for stability. The need of structural and thermodynamic details about Mg2+ interactions is then of upmost importance in the study of the structurefunction relationships. The first part of our work consists in characterizing the binding equilibria between magnesium and RNA model motifs, called kissing complexes, using native mass spectrometry (MS). MS makes it possible to distinguish individual binding stoichiometries, and the present work consisted in developing a method to quantify each species, taking into account the contribution of nonspecific adducts. We also explored how tandem mass spectrometry (MS/MS) could further help localizing magnesium ions. Further, we explored the structures of RNA complexes in the gas phase using ion mobility mass spectrometry (IMMS), with the aim to detect shape changes upon cation or ligand binding. But in contrast with anticipations, we found that DNA and RNA duplexes as well as RNA kissing complexes undergo a significant compaction at charge states naturally produced by native ESI-MS, which may hide the effect of cations. Our work showcases how mass spectrometry can bring novel information on RNA-cation binding stoichiometries and affinities, but also discusses some limitations of a gas-phase method to probe solution structures
Le, Maître Johann. „Développement de la spectrométrie de masse à ultra- haute résolution associée à la spectrométrie de mobilité ionique pour la caractérisation de coupes pétrolières lourdes. structural analysis of heavy oil fractions afterr hydrodenitrogenation by high-resolution tandem mass spectrometry and ion mobility spectrometry Structural analysis of neutral nitrogen compounds refractory to the hydrodenitrogenation process of heavy oil fractions by high-resolution tandem mass spectrometry and ion mobility-mass spectrometry Chemical characterization of 15 biocrudes obtained from hydrothermal liquefaction of industrially cultivated wild micro algae Chemical characterization with different analytical techniques, a way to understand the process: Case of the paraffinic base oil production line Exploring complex mixtures by cyclic ion mobility high-resolution mass spectrometry – Application towards Petroleum. Simulation and modeling of Collision Cross Section for structural elucidation of heavy oil fraction by ion mobility-mass spectrometry: Using polyaromatic hydrocarbons compounds mixture as calibration standard Characterization of sulfoxides compounds in dimeric distribution of heavy oil fractions by positive-ion electrospray ionization FTICR mass spectrometry Structural analysis of Petroporphyrins from asphaltene by trapped ion mobility coupled with a Fourier transform ion cyclotron resonance mass spectrometer. Cyclic ion mobility spectrometry coupled to high-resolution time-of-flight mass spectrometry equipped with atmospheric solid analysis probe for the molecular characterization of combustion particulate matter. Structural study of analogues of Titan’s haze by trapped ion mobility coupled with a Fourier transform ion cyclotron mass spectrometer“. Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR051.
Der volle Inhalt der QuelleThe evolution of oil reserves requires the use in refineries of unconventional crude oils, which are often heavier and therefore difficult to characterize. Petroleum products are in fact extremely complex chemical mixtures. The light and volatile part can be analysed by gas chromatography coupled with mass spectrometry (GC/MS), allowing the identification of compounds by using precise mass measurements and fragmentation models. However, these techniques are inappropriate for the analysis of heavy fractions. In practice, the characterization of the most complex mixtures involves the use of ultra-high-resolution mass spectrometers generally by direct analysis without chromatographic separation. The reference technique today is Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR). With a resolution of more than 106 and a mass measurement accuracy of less than 0.1 ppm, this instrument can separate all the species present in a petroleum product and assign a unique elemental composition to each m/z value. This makes it very easy to obtain molecular maps that can be presented graphically using the Kendrick diagram, the van Krevelen diagram or the number of unsaturations (DBE) as a function of the number of carbons. This thesis work has allowed thanks to the molecular characterization of petroleum products (Vacuum Gas Oil, Crude Oil, Interfacial Material, Asphaltenes and Bio-Oil...) addressing the complexity of their treatment in the refining tool. Protocols for sample analysis have been developed, using different sources of ionization at atmospheric pressure (ESI, APCI and APPI) as well as laser desorption/ionization (LDI) on the FTICR 12T mass spectrometer. Information on the isomeric content of petroleum products was then determined using ion mobility spectrometry (IMS)
Maillard, Julien. „Composition chimique du brouillard de Titan par mobilité ionique couplée à la spectrométrie de masse haute résolution Comparison of soluble and insoluble organic matter in analogues of Titan's aerosols Optimization of ion trajectories in a dynamically harmonized Fourier-Transform Ion Cyclotron Resonance cell using a Design of Experiments strategy Structural Study of Analogues of Titan's Haze by Trapped Ion Mobility Coupled with a Fourier Transform Ion Cyclotron Mass Spectrometer. High resolution mass spectrometry for future space missions: comparative analysis of complex organic matter with LAb-CosmOrbitrap and LDI-FTICR. Structural elucidation of soluble organic matter: Application to Titan's haze. Dark-ageing of analogues of aerosols in the atmosphere of the early Earth“. Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASV023.
Der volle Inhalt der QuelleAlthough the prebiotic challenge is important, the study of aerosols in the atmosphere of Titan, Saturn's largest moon, remains a challenge for the scientific community. Indeed, the data collected by the Voyager and Cassini-Huygens probes made it possible to retrieve the first information but not to unlock the secrets of this particle fog. The purpose of this thesis is to study the chemical composition of these aerosols through their reproduction on Earth. The first approach presented is molecular characterization using high resolution mass spectrometry. In this section, the comparison between the soluble and insoluble fraction of these samples and their ageing will be presented. Then, the investigation of the growth of these aerosols is presented through the use of tandem mass spectrometry. The last part of this thesis presents the study of the three-dimensional structure. For this purpose, ion mobility coupled with mass spectrometry has been used and will be reported in two parts, one in TWIMS-Synapt and the other in TIMS-FTICR. Finally, a study in Atomic Force Microscopy will be presented and will make it possible to show real structures of molecules present in aerosols thanks to the magnification provided by this type of microscope
Figueiredo, Isabel De. „Early Detection of Parkinson's Disease through Microfluidics and Ion Mobility - Mass Spectrometry Integration“. Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF070.
Der volle Inhalt der QuelleAlpha-synuclein is a critical biomarker for Parkinson's disease, however its early detection is challenging due to its low abundance and intrinsically disordered protein nature. The development of early diagnostic methods relies heavily on understanding and differentiating the structural characteristics of native alpha-synuclein versus its pathological forms, as these variations provide valuable insights into disease onset and progression. This Ph.D. thesis, investigates the conformational landscape of alpha-synuclein and explores techniques to capture and concentrate this protein without disrupting its structure. Two types of microfluidic devices are presented: the first device integrates a micro-immunopurification module optimized for alpha-synuclein capture and a micro-size exclusion chromatography module designed for desalting and buffer exchange to facilitate coupling with Ion Mobility-Mass Spectrometry. Additionally, an integrated 2-in-1 chip combines these modules into a single platform, streamlining the workflow for enhanced efficiency and accuracy in alpha-synuclein analysis. The coupling of these microfluidic devices with the Ion Mobility-Mass Spectrometry advances the structural characterization of alpha-synuclein, contributing to the development of early diagnostic methods by enabling the differentiation between native and pathological forms of the protein
Sueur, Maxime. „Characterization of organic aerosols from ship emissions by high resolution mass spectrometry : Development of new analytical methods and data visualization software“. Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMR006.
Der volle Inhalt der QuelleOrganic aerosols (OA), whether of anthropogenic or natural origin, have a major impact on the environment, both in terms of climate changes and health effects. Among the many sources of OA, the maritime transport sector occupies a far from negligible place, on the one hand, because of the annual volume of exhaust emitted and their nature, and on the other because of the proximity of emissions to inhabited areas such as ports or coastlines. Although the composition of these exhausts is monitored by means of routine analyses, it is important to study them in depth in order to fine-tune regulations on marine traffic. However, the analysis of the molecular-scale composition of a mixture as complex as ship emissions requires the use of techniques such as mass spectrometry (MS), and in particular Fourier transform mass spectrometry (FTMS). However, FTMS generates a large amount of data and generally requires the use of processing and visualization software to extract and highlight relevant information. Also, although FTMS provides information on the molecular composition of a sample, this technique does not allow the evaluation of the isomeric diversity, unlike ion mobility spectrometry (IMS). So, with the aim to characterize ship emissions, we adopted three lines of work: the development of open-access software under Python to facilitate the processing and visualization of FTMS data for the characterization of complex mixtures, the targeted characterization of petroporphyrins in naval fuels and their combustion products by Fourier transform ion cyclotron resonance (FTICR) mass spectrometry using electron transfer matrix-assisted laser desorption/ionization (ET-MALDI), and the study of structural modifications caused by photochemical aging on ship emissions using IMS-MS
Tebani, Abdellah. „Analyse métabolomique multidimensionnelle : applications aux erreurs innées du métabolisme“. Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR043/document.
Der volle Inhalt der QuelleThe new field of precision medicine is revolutionizing current medical practice and reshaping future medicine. Precision medicine intends to put the patient as the central driver of healthcare by broadening biological knowledge and acknowledging the great diversity of individuals. The prediction of physiological and pathological states in patients requires a dynamic and systemic understanding of these interactions. Inborn errors of metabolism (IEM) are genetic disorders resulting from defects in a given biochemical pathway due to the deficiency of an enzyme, its cofactor or a transporter. IEM are no longer considered to be monogenic diseases, which adds another layer of complexity to their characterization and diagnosis. To meet this need for faster screening, the metabolic profile can be a promising candidate given its ability in disease screening, biomarker discovery and metabolic pathway investigation. In this thesis, we used a metabolomic approach which is particularly relevant for IEM given their basic pathophysiology that is tightly related to metabolism. This thesis allowed the implementation of an untargeted metabolomic methodology based on a multidimensional analytical strategy including high-resolution mass spectrometry coupled with ultra-high-performance liquid chromatography and ion mobility. This work also set a methodology for preprocessing, analysis and interpretation of the generated data using experimental design and multivariate data analysis. Finally, the strategy is applied to the exploration of IEM with mucopolysaccharidoses as a proof of concept. The results suggest a major remodeling of the amino acid metabolisms in mucopolysaccharidosis type I. In summary, metabolomic is a relevant complementary tool to support the genomic approach in the functional investigations and diagnosis of IEM
Li, Xuesong. „Synthesis and physical properties of helical nanosized quinoline-based foldamers : structure, dynamics and photoinduced electron transport“. Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0013/document.
Der volle Inhalt der QuelleHerein, synthesis, characterization and application (photoinduced electron transport) of nanosized quinoline-based foldamers have been explored. With double segment strategy, a variety of helical nanosized foldamers (up to 96 quinoline units) were successfully prepared based on 8-aminoquinoline-2-carboxylic acid monomer.The dynamic properties in gas phase and solution were investigated. Ion mobility mass spectrometry afforded access to the conformation state of foldamers ingas phase; DOSY and fluorescence anisotropy assessed the diffusion (translational and rotational, respectively) of foldamers in solution. All of these techniques revealed that quinoline-based foldamers are rigid and that helical conformation is conserved. Photoinduced electron transport through nanosized foldamer was also studied and the mechanism and the transport ratios were revealed
Courrier, Benoît. „Caractérisation par spectrométrie de masse des molécules neutres induites par ablation laser“. Metz, 2000. http://www.theses.fr/2000METZ057S.
Der volle Inhalt der QuelleIdentification of neutral molecules emitted during laser materials interaction is one of the research axes developed by the Laboratoire de Spectrométrie de masse et chimie laser (LSMCL). Characterization of neutral molecules emitted during laser ablation was achived by developing a laser ablation/quadripolar mass spectrometer coupling system via gazeous chromatrography (GC/MS). The laser pyrolisis results were compared firstly those obtained by thermal pyrolisis GC/MS. They showed the strong dependance of power, the formation of aggregates and the mecanisms of decarboxylation for organic acids used as MALDI matrix. Due the introduction mode of neutral species into the chromatographic column, they was a weak sensitivity more especially for low density. The purpose of our studies was to develop and to carry out a device for identification of the neutral molecules emitted during laser ablation by increasing the detection sensitivity. Gazeous chromatography was removed and we replaced a mass spectrometer. This one is more sensitive than the GC/MS because several ionization modes can be used (electron impact EI and chemical ionization CI). When thesis is devided in two parts : the first one is confidential and will relate the presentation and the development of the device ; the second part is be devoted on the one hand, to the studied of the laser ablation of synthetic polymers and on the other hand, to the laser ablation of organic compounds used as MALDI matrix, in order to identify neutral molecules emitted
Geulin, Laurent. „Mise en place et applications du couplage entre l'électrophorèse capillaire et la spectrométrie de masse (trappe ionique)“. Rouen, 2002. http://www.theses.fr/2002ROUES060.
Der volle Inhalt der QuelleThe capillary electrophoresis (CE) is an high efficiency technique of separation but the detection. To improve it, the CE was coupling with a mass spectrometer thank to an "ionspray" interface with a liquid coaxial junction and an orthogonal geometry. The influence of specific parameters of "ionspray" interface and their interactions was studied with an experimental design approach through to a migration time of a sample zone, efficency of electrophoretic system and detector sensibility. Responses model with influent factors could be define a work zone who is a compromise to have efficient analysis in CE/MS hyphenation. Instrumental exigencies were required for reproducibility. Then, a complex mixture of non ionic polyethoxylate surfactant, the Brij 58, was analysed and the evolution of a sol-gel process was studied through to an organic modified silane, the (3- méthacryloxypropyltriméthoxysilane (MEMO), by CE/MS. The brij 58 separation is based on the complexation between the polyethoxylate chains and ammonium ion in non aqueous solvent, methanol. During the optimisation of operating conditions, the nature of the counter ion of ammonium ion was modified and influenced CE resolution and MS detection. The sensibility of CE/MS coupling could detect more than 25 oligomers of Brij 58 less than 7 picomole injected. The following of sol-gel process reaction of MEMO by CE/ESI-MS is characterised by different oligomers with a maximum of 8 chains of MEMO during 19 hours of hydrolysis reaction
Descoins, Marion. „Microscopie ionique à projection à partir d'une source à structure coaxiale“. Phd thesis, Université Paul Cézanne - Aix-Marseille III, 2007. http://tel.archives-ouvertes.fr/tel-00275122.
Der volle Inhalt der QuelleLa construction d'un spectromètre de masse adapté nous a permis d'identifier les ions produits pour des pointes de natures différentes (W, Pt et Pd) et pour différents gaz (H2, H2O et mélange H2-H2O). La richesse des ions formés relève d'une physico-chimie à l'échelle nanométrique.
Un microscope à projection intégrant cette source a été construit. Des grandissements de 500 000 ont été obtenus avec une résolution de 3Å. Outre l'intérêt évident d'une telle microscopie, ceci démontre une taille de source virtuelle inférieure à 3Å pour la source d'ions ouvrant ainsi des perspectives intéressantes en optique ionique, en FIB par exemple.
Ecker, Paul. „Etude de la répercussion des propriétés moléculaires et des caractéristiques de la pulvérisation sur la détection des ions MCs+ et MCs+2 en spectrométrie de masse d'ions secondaires“. Metz, 1998. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1998/Ecker.Paul.SMZ9847.pdf.
Der volle Inhalt der QuelleSecondary Ion Mass Spectrometry (SIMS) is a surface and interface analysis technique, the main quality of which is its sensitivity. Its principal weakness lies in the difficulty of quantification. Under Cs+ primary bombardment, this problem is strongly reduced by the monitoring of MCs+ and MCs2+ molecular ions. The aim of this work is the study of these ions through their molecular properties as well as through their formation mechanism. The stability of these molecular ions is studied by qualitative considerations supported by numerical modelling of some representative molecules. It is shown that the relative stabilities of the molecules of a series MCsx+ (x = 0 to 2) can be estimated by the application of basic chemical concepts. This work shows the importance of the formation mechanism to the analytical information carried by these ions. This is pointed out through the detailed study of isotopic ratios determined by M+, MCs+ and MCs2+ ions. These measurements enable us to evaluate the amount of ionie bombardment induced local composition changes on the sample. Finally, the evolution at certain interfaces of the signals corresponding to these ions is used to attribute formation mechanisms to them
Marinach, Carine. „Couplage orthogonal entre un piège ionique et un analyseur temps de vol IT/O-reTOF“. Paris 6, 2002. http://www.theses.fr/2002PA066247.
Der volle Inhalt der QuelleHindie, Elif. „Apport de la microscopie ionique en biologie : localisation intracellulaire et appréciation de la concentration locale de molécules marquées“. Paris 12, 1990. http://www.theses.fr/1990PA120041.
Der volle Inhalt der QuelleRuch, David. „Étude comparée des matériaux polymériques et/ou polysulfurés par ablation/ionisation laser et bombardement ionique couplés à la spectrométrie de masse : Application à la caractérisation d'élastomères vulcanisés“. Metz, 2002. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2002/Ruch.David.SMZ0223.pdf.
Der volle Inhalt der QuelleMarie, Arul. „Études structurales des oligomères fluorés par spectrométrie de masse : mécanisme de désorption et orientation des processus de dissociation“. Paris 6, 2002. http://www.theses.fr/2002PA066246.
Der volle Inhalt der QuelleLê, Thi Ngà. „Etude structurale de biomolécules de grandes tailles, en phase gazeuse, par spectroscopie infrarouge, spectrométrie de mobilité ionique et dissociation induite par attachement d'électron“. Thesis, Paris 13, 2014. http://www.theses.fr/2014PA132017.
Der volle Inhalt der QuelleGas-phase studies of large biological molecules have emerged with the advent of soft production methods of biomolecular ions under vacuum (like ESI or MALDI) combined to mass spectrometry. The first aim of this work was to use three complementary experimental techniques, namely IRMPD spectroscopy, ion mobility mass spectrometry and electron capture dissociation ECD to probe the gas-phase structures of amyloïd Aβ₁₂-₂₈ and tryptophan zippers TZ1 and TZ4 peptides. The main originality of this study is to analyse the specific c/z product ion abundances in ECD experiments with the structural information gained through IR spectroscopy and ion mobility experiments. With this complementary approach, we were able to assign the most probable gas-phase structures of these flexible peptides. In particular, it is shown that the native structure of the peptides is not conserved in the gas phase. This study relies on the interplay between experiments and theoretical calculations. To that end, we used several theoretical methods, ranging for molecular dynamics using a classical force field (AMBER) to quantum mechanics calculations to simulate the vibrational spectra of the peptides. The second aim of this work was to design, develop and optimize a unique device, coupling a novel source introducing biomolecules in the gas phase, based on laser desorption from liquid micro-droplets directly into vacuum, coupled with a time-of-flight mass spectrometer. This desorption source is an original alternative to the usual methods (ESI or MALDI). Through mass spectrometry techniques, it should allow investigating the complexation processes of non-covalently bound species in conditions as close as the ones encountered in solution. We have recently obtained the first mass spectra. Due to the high velocity spread of the desorbed ions, new developments are needed to improve the mass resolution. In particular, we plan to transfer the ions in a quadrupole ion trap and to perform the laser desorption in front a pulsed valve to stream the ions in the supersonic expansion
Nsouli, Bilal. „Apport de la technique PDMS à l'étude des modifications induites dans des polymères utilisés en ambiance nucléaire“. Lyon 1, 1995. http://www.theses.fr/1995LYO10186.
Der volle Inhalt der QuelleBardin, Noémie. „Composition isotopique des éléments légers dans les micrométéorites ultracarbonées par spectrométrie de masse à émission ionique secondaire à haute résolution en masse, contribution à la connaissance des surfaces cométaires“. Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS189/document.
Der volle Inhalt der QuelleThis thesis covers the isotopic analysis of carbon-rich interplanetary dust (ultracarbonaceous micrometeorites), in order to better understand the isotopic fractionation process of light elements (hydrogen and nitrogen) observed in the organic phases of primitive extraterrestrial matter. It is possible, within a collection of micrometeorites coming from the central regions of the Antarctic continent, to identify ultra-carbonaceous micrometeorites (UCAMMs – for Ultra-Carbonaceous Antarctic MicroMeteorites) which contain about ten times more carbon than the primitive meteorites. These particles are extremely rare and open the possibility to study in laboratory cometary particles of large sizes (100-200 microns). This thesis focuses on the isotopic analyses of UCAMMs, in order to understand the isotopic fractionation processes of light elements (hydrogen and nitrogen) observed in the organic matter of the primitive solar system. Mineralogical, chemical and structural analyses on two fragments of ultra-carbonaceous micrometeorites were performed in the framework of collaborations using techniques of scanning electron microscopy, electron microprobe, infrared microspectroscopy (SOLEIL synchrotron). The main work of this thesis concerns the isotopic analysis of two UCAMMs by Secondary Ion Mass Spectrometry (SIMS) using the NanoSIMS ion microprobe. The instrumental developments performed in collaboration between the CSNSM and the Curie Institute teams allow to resolve molecular interferences with a mass resolving power higher than 20 000 retaining a sensibility compatible with the measurements considered here. So, it has been possible to measure for the first time the hydrogen isotopic composition with the polyatomic ions 12C2D- and 12C2H- and to compare its spatial distribution with that of the nitrogen (12C15N-/12C14N-) obtained on the same surface with the same magnetic field. A protocol for producing a series of standard samples was developed from polymers isotopically enriched in deuterium in order to determine the instrumental fractionation of the NanoSIMS showing the possibility to perform precise measurements of the hydrogen isotopic composition in the organic matter with polyatomic ions (CD-/CH- and C2D-/C2H- ratios). The isotopic maps at high spatial resolution (200 nm) in C2D/C2H and C15N/C14N show a very heterogeneous distribution in deuterium with extreme values going up to 20 times the terrestrial ocean value, whereas the 15N/14N ratios remain globally close (within 20%) to the terrestrial atmosphere value. Measurements of N/C ratios in ion imaging performed at the NanoSIMS confirm the values measured by electron microprobe and show that the organic matter of UCAMMs is rich in nitrogen. Comparisons between isotopic images with each other and with the images obtained by the other techniques show that the organic matter of ultracarbonaceous micrometeorites is constituted of different components. The main component doesn’t exhibit a correlation between the D and 15N excesses. A minor component of the analyzed surface exhibits correlated excesses in D and in 15N, without neither the elemental or structural composition of this component significantly differs from the rest of the grain. Finally, a minor component showing moderate enrichments in D and 15N/14N ratios lower than the terrestrial atmosphere value could have been identified.All the data can be explained assuming that the ultracarbonaceous micrometeorites come from the surface of transneptunian icy objects. The elemental and isotopic characteristics observed in the organic matter of UCAMMs might result from the mixing of different strata of the parent body having undergone irradiation by the galactic cosmic radiation at large heliocentric distances
Carette, Michel. „Etude expérimentale d'une source ionique par capture d'électrons d'atomes excités dans des états de Rydberg : application à la spectrométrie de masse de polluants atmosphériques“. Aix-Marseille 1, 1999. http://www.theses.fr/1999AIX11065.
Der volle Inhalt der QuelleAllali, Hakim. „Aspects de l'émission ionique secondaire induite dans des couches isolantes inorganiques par des ions argon d'une dizaine de MeV“. Lyon 1, 1993. https://tel.archives-ouvertes.fr/tel-00746656.
Der volle Inhalt der QuelleArribard, Yann. „Analyse de matière extraterrestre primitive par imagerie hyperspectrale infrarouge et spectrométrie de masse TOF-SIMS“. Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASP005.
Der volle Inhalt der QuelleSo-called primitive extraterrestrial matter is characterized by its low chemical evolution since its formation. It is found in particular as one of the constituents of the fragments of small bodies of the Solar system, such as asteroids. The study of samples from these bodies can thus make it possible to better understand its origin and its evolution.In this thesis, my work focused on the analysis of primitive matter and more particularly on the study of carbonaceous chondrites having undergone aqueous alteration. The first part of my thesis focuses on the analysis of mineral and organic phases within petrological type 2 CM chondrites using infrared and Raman spectroscopy techniques as well as time-of-flight secondary ionization mass spectrometry. (TOF-SIMS). These techniques benefit from a good complementarity in the characterization of the different phases that interest us. They are also coupled with imagery, which makes it possible to study the link that may exist between the different mineral and organic phases. I used a new unsupervised process for analyzing infrared hyperspectral data, which made it possible to determine spectral parameters characterizing the state of progress of the aqueous alteration of the samples, in particular of their mineral phase, while relating to their chemical evolution. Raman spectroscopy made it possible to highlight differences in the structure of the polyaromatic organic matter within the different samples. Finally, the TOF-SIMS also highlighted a difference in the structure of the organic matter while confirming and clarifying the differences in co-localization between organic matter and mineral phase observed by hyperspectral imaging between the samples.The second part of my thesis focused on the study of the effectiveness of a new linear accelerator - Andromeda (IJCLab) - as a primary source for TOF-SIMS on analogues of primitive chondrite matter. I produced these organic analogues in the laboratory to simulate insoluble organic matter, the majority of organic matter in chondrites. I checked the characteristics of these analogues by infrared spectroscopy, X-ray spectroscopy and TOF-SIMS. They remain different from CM organic matter in terms of poly-aromatic structure, but similar in terms of elemental composition and insoluble character. I have produced mineral analogues from earth rocks similar to minerals found in CM chondrite. The measurements that I carried out on these analogues and on chondrites show both the potential and the current limits of TOF-SIMS coupled to Andromede, and suggest areas for improvement with a view to increasing, in particular, the masse resolution
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.
Der volle Inhalt der QuelleInstalled 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
Oladipo, Adewale. „Désorption stimulée induite par des agrégats d'hydrogène (E ≤ 120 keV-u) et des ions lourds (E ≤ 400 keV-u) : applications analytiques“. Lyon 1, 1988. http://www.theses.fr/1988LYO10032.
Der volle Inhalt der QuelleTolu, Julie. „Spéciation et mobilité du sélénium présent dans les sols à l’état de traces : contribution aux prévisions à long terme“. Thesis, Pau, 2012. http://www.theses.fr/2012PAUU3002/document.
Der volle Inhalt der QuelleA radioactive isotope of selenium was shown to be among the most critical radionuclide forsafety assessment of high level and long lived nuclear waste repository in case of hypotheticalsoil contamination. A methodology was thus developed to determine Se species (speciation)present in soils at trace level (μg kg-1; radiological context) in assessing their leaching andretention phases (distribution). Combined to a 77Se(IV) tracer, kinetically limited processes were shown to be involved in Se retention and chemical transformations in soils, suggesting that native Se behavior is particularly relevant for its long term mobility assessment and modeling. The investigation of native Se speciation and distribution in 29 soils has finally highlighted that soil organic matter impact the nature of Se species susceptible to be leached (organic and colloidal compounds) and the Se mobility (Se stabilization in solid phase via organo-mineral associations)
Sévelin-Radiguet, Nicolas. „Dispersions temporelles et énergétiques en émission ionique : application à la Sonde Atomique Tomographique assistée par laser“. Rouen, 2014. http://www.theses.fr/2014ROUES064.
Der volle Inhalt der QuelleAtom Probe Tomography is a nano-analysis technique able to map chemical species with atomic resolution in 3D within the sampled volumes. Surface atoms are field-evaporated from the specimen surface. Time-of-flight mass spectrometry assigns their chemical nature. Ultra-short laser pulses used to trigger the evaporation process allow analysing a broad range of materials (from metals to insulators). This thesis deals with two aspects of the use of ultra-short laser pulses in atom probe. The first part is an experimental and theoretical work about laser-assisted field evaporation mechanisms of silicon. Laser illumination and intense electric field confine carriers near the semi-conductor surface. Optical properties change and appear quasi-metallic. The second part of this thesis focuses on the energy spreads of the emitted ions. Various technological limitations previously hid this dispersion of energy. A new electrostatic lens allows us to measure such quantities. We show results on various materials (metals, semi-conductors and oxides) and suggest some possible explanations. Atom probe is not only a powerful analytical microscope but becomes an energy spectroscope as well
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.
Der volle Inhalt der Quelle