Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 47 for “"Desolvation"”.
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Reduction of polyatomic ion interferences in inductively coupled plasma mass spectrometry with cryogenic desolvation
<p>A new desolvation scheme for the introduction of aqueous and organic samples into an argon inductively coupled plasma (ICP) is described. The aerosol generated by the nebulizer is heated (+140°C) and cooled (-80°C) repeatedly. The dried aerosol is then injected into an inductively coupled plasma …
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Developing and Utilizing Gas-phase Laser Spectroscopy Techniques to Study the Effect of Desolvation on Molecules
… however, are found in solution and therefore desolvation is required for the analytes to be introduced into the mass spectrometer. This process, and the gas phase environment may fundamentally change the properties of the analyte due to the removal of intermolecular interactions. On the other …
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Structures and thermal decompositions of pseudopolymorphs of sulfonamide drugs
… properties of the crystals as stabilities, desolvation processes and their kinetics as well as the melting of pure polymorphic forms of the drugs resulting from desolvation. Complementary studies of the compounds using X-ray powder diffraction (XRD) and DSC allowed identification and …
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MANIPULATION OF ELECTROSPRAY GENERATED DROPLETS USING VARIOUS VAPORS
Volatile reagents can be entrained in desolvation gas to manipulate electrospray generated droplets. These reagent vapors are admitted into the atmospheric interface region of a QqTOF tandem mass spectrometer. The electrospray droplets interact with the reagent vapors between the curtain and …
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Inclusion compounds of multipedal hosts
… scanning calorimetry. The kinetics of desolvation for some of the inclusion compounds was determined using isothermal thermogravimetry. Rate laws describing the desolvation mechanisms are ascribed, and the activation energies determined.
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Separation of close isomers by enclathration
… their relative stability. The kinetics of desolvation of the picoline and lutidine inclusion compounds were studied, using isothermal and non-isothermal thermogravimetry. These experiments yielded the kinetic models as well as the activation energies of the desolvation reactions. …
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SAMPLE INTRODUCTION AND INSTRUMENTATION IN PLASMA SPECTROMETRY
… function and application of a number of novel desolvation systems have been investigated in this study to decrease this loading and facilitate operation with volatile organic solvents.
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Evaluation of Ion Transfer Capillary Geometry on Sensitivity of a Desorption Electrospray Ionization and Mass Spectrometry System
… taken by the DESI-MS owing to increased ion desolvation. This thesis studies how changing the inner diameter and cross-sectional profile of the capillary can improve ion desolvation by increased heat transfer to the center of the flow. Increasing heat transfer efficiency can obviate such high …
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UNDERSTANDING AND EVALUATING CRYSTAL POLYMORPHISM BY SECOND HARMONIC GENERATION MICROSCOPY
… within the droplet, and furthermore rapid desolvation favors the kinetic factor to trap the rare metastable polymorphs. Second harmonic generation microscopy (SHG) possesses enough sensitivity to detect sub-micrometer size chiral crystals selectively and has the potential for use in crystal …
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Revisiting and re-computing the X-score scoring function
… atomic interaction to account for entropic desolvation factors on ligand binding. We thereafter re-compute the revised scoring function and test the output against multiple sets of data to examine the robustness of the heuristic weightings used.
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Non-Covalent Interactions in Water Using Synthetic and Biological Receptors
… to polar functional group interactions, partial desolvation of polar and non-polar surfaces and changes in conformational flexibility. Here, conformationally well-defined supramolecular complexes formed between four different calix[4]pyrrole receptors and thirty different pyridine N-oxide guests …
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Structure and reactivity of selected inclusion compounds
… and X-ray powder diffraction. The kinetics of desolvation of all the inclusion compounds in class A and B were studied, using isothermal or programmed temperature thermogravimetry. Attempts were made to describe the kinetic behaviour in terms of the crystal structures of these compounds. The …
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Crystal engineering and sorption studies of cyclotriveratrylene and C-methylcalix[4]resorcinarene solvates
… transformation following desolvation. Consecutive single-crystal X-ray diffraction experiments on 1 at 50 °C reveal that the rotation of a unique, single methoxy group of the host molecule may permit the escape of the solvent molecules from the apparently nonporous crystal. …
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Studies of solute retention in HPLC using hydrophobic pairing ions with octadecylsilica.
… of retention involving both ion-exchange and desolvation is proposed and a quantitative relationship formulated between capacity factor and adsorbed pairing ion concentration. The agreement between the predicted capacity factors and those obtained by direct measurement is discussed. The above …
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Investigation of ion transfer efficiency through multi-channel capillaries for a Desorption Electrospray Ionization (DESI) interface
… study illustrates the complex tradeoff between desolvation and ion loss, thereby providing a general guideline to instrumentation design for the purpose of maximizing signal intensity of the MS.
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ANALYSIS OF PHARMACEUTICALS AND BIOMOLECULES USING HPLC COUPLED TO ICP-MS AND ESI-MS
… in the pharmaceutical industry. A membrane desolvation interface has been evaluated for coupling high performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP-MS). Desolvation of the sample prior to reaching the plasma was shown to facilitate a …
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Evaluation of a particle beam interface for LC/MS
… four independent variables (helium flow, desolvation chamber temperature, source temperature, and 96 methanol) and their effects on peak width. A Box–Behnken experimental design is used and described. Response surfaces are generated from the best fit equation describing the data.
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From Solution Into the Gas Phase: Studying Protein Hydrogen Exchange and Electrospray Ionization Using Molecular Dynamics Simulation
… Residual charge carriers remain following desolvation, consistent with Dole’s charged residue model.
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Investigation of mass spectrometric interfaces for supercritical fluid chromatography and liquid chromatography
… which affect the nebulization and the subsequent desolvation of the droplets were assessed. The quantitative performance was evaluated yielding a limit of detection (LOD) of 40 ng (caffeine) for scan data which is some 3 to 25 times lower than previously reported studies. Operation of the …
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Molecular selectivity by host-guest methods
… by thermal analysis (TGA, DSC), kinetics of desolvation, Hirshfeld surface analysis, and activation energy of desolvation-analysis techniques. During the separation of the trimethoxybenzene (TMB) isomers, cholic acid and deoxycholic acid' hosts were used in chapter 3. It was found that each …
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