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Tesi sul tema "Chromatography"

Autore: Grafiati
Pubblicato: 4 giugno 2021
Ultima modifica: 29 luglio 2024

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1

Mekaoui, Nazim. "Contribution à l'étude de la chromatographie à contre-courant : partage de composés ionisables, nouvelles colonnes et purification séquentielles". Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10249/document.

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La chromatographie à contre courant (CCC) est une technique de purification chimique préparative quitravaille avec un système biphasique liquide. Une phase est la phase mobile, l'autre phase est la phasestationnaire. Il n'y a aucun support solide: un champ de force centrifuge est utilisé pour maintenir en place laphase stationnaire. Ce travail est une contribution à l'étude de la purification préparative par CCC. Après uneimportante étude bibliographique des procédés de purification en continu tant en CCC qu'autres, il est montréque la méthode dite "multi-dual-mode", ou MDM, est une solution possible. Elle consiste à utiliser le fait queles deux phases liquides peuvent servir de phase stationnaire: il suffit d'inverser le sens de circulation et lanature de la phase mobile (méthode dual-mode). Le mélange est séparé de façon classique pendant untemps chronométré, puis on inverse le rôle des phases: la phase mobile devient stationnaire et vice versa eton inverse également le sens de circulation (ascendant devient descendant ou vice versa). On sort lescomposants du mélange soit d'un coté de la colonne CCC, soit de l'autre. La méthode est mise en oeuvrepour purifier le Bleu de Coomassie en le débarassant des ses composés polaires (d'un coté) et apolaire (del'autre coté de la colonne et en accumulant dans la colonne la fraction de polarité intermédiaire, fractiond'intérêt. Une nouvelle colonne hydrostatique de petit volume (30 mL) a également été testée: elle permetde tester un nouveau système liquide très rapidement
Counter-current chromatography (CCC) is a preparative purification technique that works with the twoliquid phases of a biphasic liquid system. One phase is used as the mobile phase when the other phase isused as the stationary phase. There is no solid support: centrifugal fields are used to obtain a support-freeliquid stationary phase. This work contains an exhaustive bibliographic study of what can be found in theliterature concerning continuous chromatographic processes. The multi-dual-mode (MDM) process was foundto be the best one able to purify large amount of crude mixtures. The MDM method starts with a classicalseparation of the mixture followed by a switch of both the liquid phase nature and the flowing direction. Themobile phase flowing e.g. in a descending direction becomes the stationary phase. The previous stationaryphase becomes the mobile phase flowing in the ascending direction (or vice versa). The purified compoundsof the introduced mixture are eluted at one side of the column or the other according to their polarity. TheMDM method was used to purify a crude sample of Coomassie Blue: the polar part of the dye was eluted atthe column top (or head) and the apolar part at the column bottom (or tail) while the essential part of the dyewas trapped inside the CCC column. The work also presents a new small volume (30 mL) hydrostatic CCCcolumn. It is shown that this column could be used to test quickly the potential of a given biphasic liquidsystem
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2

Power, Gillian Mary. "The study of chromatographic interactions using model reversed-phase chromatography surfaces". Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285643.

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3

Galindo, Irma C. (Irma Concepcion). "Investigation Into the Causes for the Loss of Resolution in an Ion Chromatograpy Resin". Thesis, North Texas State University, 1988. https://digital.library.unt.edu/ark:/67531/metadc798197/.

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Abstract (sommario):
Four mechanisms were considered as possible causes of the loss in resolution for a Dionex CG2 ion chromatography resin: 1) presence of inorganic ions strongly bound to the active sites; 2) adsorption of organic species; 3) physical alterations; and 4) chemical alterations. The instrumental analyses used to gather data were ICP, FT-IR, SEM, solid C-13 NMR and IC. Based on the results, no metal ions are bound to the resin, no organic species are held onto the resin, and no physical change was observable. The cause for the loss of resolution is a strong reduction in the number of active sites in the resin as confirmed by elemental analysis for the sulfur in the sulfonic acid present in the active sites.
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4

McBrady, Adam Dewey. "Microfabricated chromatographic instrumentation for micro total analysis systems /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8570.

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5

Kirk, John Daniel. "Particle beam LC/MS with fast atom bombardment". Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/27127.

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6

Prazen, Bryan J. "Development of high speed hyphenated chromatographic analyzers and second order data analysis techniques /". Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/11550.

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7

Cao, Liming. "Protein Separation with Ion-exchange Membrane Chromatography". Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050405-174109/.

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8

Meacham, Robert Ian. "Sorption-effect chromatography". Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/27095.

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The objective of this work has been to develop an understanding of the changes in volumetric flow rate that occur during chromatography so that flow rate measurements can be used as the basis of an analytical method. It is suggested that the total amount of gas which adsorbs on a column equals the total amount of gas which elutes from the end of the column.
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9

Lyne, P. M. "Heater displacement chromatography". Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376927.

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10

Yang, Wei. "Solids phase chromatography". Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505060.

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Abstract (sommario):
The present study focuses on the development of a novel technique, namely Solids Phase Chromatography (SPC), for particle classification and size analysis. SPC is a fractionation based technique and utilises a separation channel to fractionate the particle samples into sub-fractions according to their sizes. Subsequently, the products may be analysed by various detectors and recovered for other investigations.
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11

g, Fong Siong Fong. "Chemometrics and chromatography". Thesis, University of Bristol, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535216.

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12

Liddy, Alison Mary. "Multifunctional chromatography supports". Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/594/.

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The aim of this study was to create a bi-layered packed bed chromatography support for the purification of nano-sized bioproducts. The effect of three different chemistry approaches, different solvent conditions, and microwave heating were investigated on construction of a bi-layered support. Sepharose CL-6B was activated with allyl glycidyl ether (routes 1&2). The inert outer layer was created in route 1 by reacting bromine with the allyl groups at the surface, followed by the addition of sodium hydroxide. Creation of the outer layer in route 2 was achieved by oxidation of surface groups with potassium permanganate. In both synthesises the allyl groups remaining were reacted with bromine and a charged amine ligand was coupled to the inner core. The activation step of route 3 resulted in the introduction of three membered epoxide groups throughout the support. Surface groups were reacted with sodium hydroxide or hydrochloric acid. Finally a charged amine ligand was coupled to the support by reacting trimethylamine hydrochloride with the remaining epoxide groups. Supports created by route 1 eliminated 91% of plasmid DNA binding whilst maintaining a high protein binding capacity. This was achieved by using DMS0 as the solvent in the bromination step and employing microwave heating. Route 2 proved to be the least successful in creating a bi-layered support. The beads created under hydrochloric acid-methanol conditions (route 3) reduced 91% of the plasmid DNA binding whilst maintaining a high protein binding capacity. This study revealed that microwave heating was a useful tool in the synthesis of chromatography supports. Subsequently, a comprehensive study was untaken investigating the effects of microwaves on numerous chromatography matrices.
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13

Mule, S. A. "Studies in chromatography". Thesis(M.Sc.), CSIR-National Chemical Laboratory, Pune, 1990. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3030.

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14

Tambe, A. S. "Studies in chromatography". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1992. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3041.

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15

Allyn, M. Liz. "Indirect photometric chromatography of iodide ion in aqueous solutions /". Online version of thesis, 1987. http://hdl.handle.net/1850/8769.

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16

Ley, Adrian. "Matrix gestützte Polymernetzwerke für die Anwendung in der konvektiven präparativen Chromatographie". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/11858/00-1735-0000-002E-E558-6.

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17

Al-Sayegh, A. J. "Determination of mixtures of sulfonamides by pyrolysis-gas chromatography following thin-layer chromatographic separation". Thesis, University of Kent, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379714.

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18

Colby, Christopher Brett. "Optimisation of scale-up of chromatography /". Title page, table of contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phc686.pdf.

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19

Wong, Victor, University of Western Sydney, of Science Technology and Environment College e of Science Food and Horticulture School. "A fundamental study towards improving the performance of liquid chromatographic separation". THESIS_CSTE_SFH_Wong_V.xml, 2003. http://handle.uws.edu.au:8081/1959.7/467.

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Abstract (sommario):
The three factors of the resolution (Rs)equation(see Equation 1.1)were explored in this thesis. During the course of the research project, an important aim was to explore separation processes that would lead to an increase in productivity without sacrificing Rs. To that end, an increase in the retention factor (k)to enhance Rs was deemed detrimental to the cycle time, hence the production rate, particularly when preparative separations are involved. Consequently the primary objectives were to (i)prepare more efficient columns and (ii)investigate new strategies in manipulating selectivity. The significance of the work contained in this thesis is highlighted in 27th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2003)held in Nice, France between 15-19 June, 2003. Many of the papers presented significantly compared to chapters contained in this research
Doctor of Philosophy (PhD)
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20

Michelsen, Peter J. "Relationship between chromatographic retention and donor and acceptor numbers /". Online version of thesis, 1990. http://hdl.handle.net/1850/10688.

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21

Jedrzejewski, Paul T. "Investigation of mass spectrometric interfaces for supercritical fluid chromatography and liquid chromatography". Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-08282003-155244/.

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22

Fuchs, Géraldine. "Étude du fractionnement d'énantiomères par chromatographie a l'échelle semi-industrielle". Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL031N.

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Abstract (sommario):
Contrairement aux autres méthodes enantiosélectives comme la cristallisation ou la conversion enzymatique, les procédés chromatographiques tendent à se généraliser grâce au nombre croissant de phases disponibles sur le marché; parallèlement la chromatographie chirale est surtout utilisée à l'échelle analytique, du fait du cout très élevé de ces phases, de leur faible capacité, et aussi de leur diffusion commerciale limitée. Dans ce travail, nous présentons des résultats expérimentaux obtenus à l'échelle préparatoire par deux procédés classiques d'élution (phase supercritique, phase gazeuse), ainsi que par un procédé fonctionnant selon le concept de lit mobile simule (éluant liquide). La résolution en chromatographie supercritique de trois oxydes de phosphine et du (trifluoro-2,2,2)-(anthryl-9) éthanol a conduit à des productivités significatives d'énantiomères de haute pureté. La résolution d'un époxyde racémique a montré la supériorité du procédé en lit mobile simulé par rapport au procédé classique d'élution. Finalement, le fractionnement en chromatographie en phase gazeuse de l'acétate d'octene-1-yle-3, offre des résultats encourageants sur une phase -cyclodextrine permethylée
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23

Marlot, Léa. "Développement de méthodes bidimensionnelles préparatives CPCxLC : application à la purification de molécules d'intérêt issues de matrices végétales". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1299/document.

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La chromatographie bidimensionnelle préparative suscite de plus en plus d'intérêt dans l'élucidation d'échantillons complexes car elle permet de collecter un grand nombre de molécules à haute pureté et quantitée récupérée. Bien que la chromatographie liquide (LC) soit souvent choisie en deuxième dimension, la chromatographie de partage centrifuge (CPC) à de multiples avantages qui en font une technique de choix pour la première dimension. Dans le but de purifier plusieurs molécules d’intérêt dans les matrices végétales, le couplage «comprehensive» CPCxLC représente une technique à fort potentiel. Après avoir expliqué son intérêt et les enjeux liés à la séparation préparative en mode «comprehensive», le développement d’une telle séparation est étudiée selon trois axes. Tout d’abord, une purification de deux molécules d’intérêt dans la plante Edelweiss est réalisée à l’échelle industrielle grâce à la réalisation de cartographies 2D au laboratoire. Cette application permet de montrer l’intérêt du couplage et de mettre en évidence les verrous liés aux conditions de transfert total des fractions en deuxième dimension. Dans une deuxième partie, la séparation CPCxLC en mode « comprehensive » est développée avec le transfert total de l’échantillon en deuxième dimension pour la purification de cinq composés cibles présents dans la plante Edelweiss. Les points clés de la séparation CPCxLC, à savoir le temps d’échantillonnage et le transfert en deuxième dimension, sont étudiés au regard du couplage LCxLC afin de garantir une qualité de séparation permettant la récupération totale des composés. Enfin, la troisième partie consiste à la mise en place d’une méthodologie de sélection des systèmes CPCxLC basée sur l’évaluation quantitative du potentiel des systèmes bidimensionnels à apporter de la distance entre les pics. Cette procédure de sélection est développée sur l’échantillon Cyclopia genistoides avec l’objectif d’isoler huit composés cibles
Preparative two-dimensional chromatography is gaining interest in the elucidation of complex samples as it allows the collection of a large number of molecules with high recovered purity and quantity. While the second dimension is often selected to be liquid chromatography (LC), centrifugal partition chromatography (CPC) is a technique with multiple advantages representing a suitable first dimension. In order to purify several molecules of interest in plant matrices, the comprehensive CPCxLC represents a technique with high potential. After explaining its interest and the issues related to the preparative separation in comprehensive mode, the development of such a separation is studied according to three axes. Firstly, a purification of two targeted molecules in Edelweiss plant is carried out at industrial scale thanks to the realization of 2D-contour plot. This application allows to expose the interest of the separation and to highlight the locks related to the conditions of total transfer of the fractions in second dimension. In a second part, the comprehensive CPCxLC separation is developed with the total transfer of the sample in second dimension applied to the purification of five target compounds from Edelweiss plant. The key points of the CPCxLC separation, namely the sampling time and the second dimension transfer, are studied with regard to the LCxLC separation in order to ensure a separation quality allowing the total recovery of the compounds. Finally, the third part consists in the implementation of a CPCxLC system selection methodology based on the quantitative evaluation of the potential of two-dimensional systems to generate distance between peaks. This selection procedure is developed on the sample Cyclopia genistoides with the objective of isolating eight target compounds
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24

Shalliker, Ross Andrew, e mikewood@deakin edu au. "Studies on the behaviour of polystyrene in reversed phase chromatography". Deakin University. School of Sciences, 1992. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20051125.112118.

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Polystyrene behaviour in reversed phase high performance liquid chromatography was influenced mainly by the solvent system, but secondary affects were observed depending on the stationary phase. A variety of reversed phase columns were investigated using mobile phase combinations of dichlorom ethane-methanol, dichloromethane-acetonitrile, ethyl acetate-methanol and ethyl acetate-acetonitrile. Several different modes of behaviour were observed depending on the polymer solubility in the solvent system. In the dichloromethane-methanol solvent system, polymer-stationary phase interactions only occurred when the molecules had pore access. Retention of excluded polystyrene depended on the kinetics of precipitation and redissolution of the polymer. Peak splitting and band broadening occurred when the kinetics were slow and molecular weight separations were limited !o oligomers and polystyrenes lower than 5-10(4) dalton. Excellent molecular weight separations of polystyrenes were obtained using gradient elution reversed phase chromatography with a dichloromethane-acetonitrile mobile phase on C18 columns. The retention was based on polymer-stationary phase interactions regardless of the column pore size. Separations were obtained on large diameter pellicular adsorbents that were almost as good as those obtained on porous adsorbents, showing that pore access was not essential for the retention of high molecular weight polystyrenes. In the best example, the separation ranged from the monomer to 10(6) dalton in a single analysis. Very little adsorption of excluded polymers was observed on C8 or phenyl columns. Polystyrene molecular weight separations to 7-10(5) dalton were obtained in an ethyl acetate-acetonitrile solvent system on C18 columns. Adsorption was responsible for retention. When an ethyl acetate-methanol solvent system was used, no molecular weight separations were obtained because of complex peak splitting. Reversed phase chromatography was compared to size exclusion chromatography for the analysis of polydisperse polystyrenes. Similar results were obtained using both methods. However, the reversed phase method was less sensitive to concentration effects and gave better resolution.
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25

Borneman, Zandrie. "Particle loaded membrane chromatography". Enschede : University of Twente [Host], 2006. http://doc.utwente.nl/57597.

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26

Akbar, Muhammad. "Chip-Scale Gas Chromatography". Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/56566.

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Abstract (sommario):
Instrument miniaturization is led by the desire to perform rapid diagnosis in remote areas with high throughput and low cost. In addition, miniaturized instruments hold the promise of consuming small sample volumes and are thus less prone to cross-contamination. Gas chromatography (GC) is the leading analytical instrument for the analysis of volatile organic compounds (VOCs). Due to its wide-ranging applications, it has received great attention both from industrial sectors and scientific communities. Recently, numerous research efforts have benefited from the advancements in micro-electromechanical system (MEMS) and nanotechnology based solutions to miniaturize the key components of GC instrument (pre-concentrator/injector, separation column, valves, pumps, and the detector). The purpose of this dissertation is to address the critical need of developing a micro GC system for various field- applications. The uniqueness of this work is to emphasize on the importance of integrating the basic components of μGC (including sampling/injection, separation and detection) on a single platform. This integration leads to overall improved performance as well as reducing the manufacturing cost of this technology. In this regard, the implementation of micro helium discharge photoionization detector (μDPID) in silicon-glass architecture served as a major accomplishment enabling its monolithic integration with the micro separation column (μSC). For the first time, the operation of a monolithic integrated module under temperature and flow programming conditions has been demonstrated to achieve rapid chromatographic analysis of a complex sample. Furthermore, an innovative sample injection mechanism has been incorporated in the integrated module to present the idea of a chip-scale μGC system. The possibility of using μGC technology in practical applications such as breath analysis and water monitoring is also demonstrated. Moreover, a nanotechnology based scheme for enhancing the adsorption capacity of the microfabricated pre-concentrator is also described.
Ph. D.
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27

Hensley, Jack Lee. "Capillary supercritical fluid chromatography". Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/53623.

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The modification of a gas chromatograph for capillary supercritical fluid was demonstrated. The resulting instrument was used to characterize the performance of capillary columns manufactured specifically for SFC applications. The columns were tested for inertness, efficiency, and immobilization before and after extraction with the supercritical CO₂ solvent. Stable deactivation layers were obtained with polyethylene glycol pyrolysis of Carbowax 20M and Superox 20M. Crosslinking was evaluated with dicumyl peroxide (DCP) and azo-t-butane (ATB) as free radical initiators with OV-1701 as a stationary phase. ATB was found to yield more efficient crosslinking and had less effect on column polarity. Quantitative reproducibility of SFC was evaluated for alkanes, alcohols and acids on columns which were deactivated by polyethylene glycol pyrolysis or by mixed cyclic siloxanes. Both gave better reproducibility than an untreated column but the overall reproducibility of the polyglycol deactivation was better than the cyclic deactivation. Liquid CO₂ extraction was performed on a variety of spices and food products. This sample preparation proved useful in isolating CO₂ soluble materials from complex matrices which were insoluble in CO₂.
Ph. D.
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28

Mertzman, Melissa Danielle Foley Joe Preston. "Chiral microemulsion electrokinetic chromatography /". Philadelphia, Pa. : Drexel University, 2004. http://dspace.library.drexel.edu/handle/1860/340.

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29

Reiner, George Allen. "An explosive vapor generator based on capillary gas chromatography". Diss., Virginia Tech, 1990. http://hdl.handle.net/10919/39761.

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30

Foster, Austin Richard. "Thermal Gradient Characterization and Control in Micro-Fabricated Gas Chromatography Systems". BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/7481.

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Abstract (sommario):
In order to make gas chromatography (GC) more widely accessible, considerable effort has been made in developing miniaturized GC systems. Thermal gradient gas chromatograpy (TGGC), one of the heating methods used in GC, has recieved attention over the years due to it's ability to enhance analyte focusing. The present work seeks to develop high performance miniaturized GC systems by combining miniaturized GC technology with thermal gradient control methods, creating miniaturized thermal gradient gas chromatography (µTGGC) systems. To aid in this development a thermal control system was developed and shown to successfully control various µTGGC systems. DAQ functionality was also included which allowed for the recording of temperature and power data for use in modeling applications. Thermal models of the various µTGGC systems were developed and validated against the recorded experiemental data. Thermal models were also used to aid in decisions required for the development of new µTGGC system designs. The results from the thermal models were then used to calibrate and validate a stochastic GC transport model. This transport model was then used to evaluate the effect of thermal gradient shape on GC separation performance.
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31

Silwal, Indira K. C. "Characterization of Unknown Chemicals Using Gas Chromatography/Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and AB-Initio Calculations". Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/SilwalIKC2008.pdf.

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32

Ashraf-Khorassani, Medhi. "Supercritical fluid chromatography of nitrogen-containing compounds on packed columns". Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/49919.

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The separation of basic nitrogen-containing compounds has been investigated via supercritical CO₂ and 1% methanol modified CO₂. Packed columns with the following stationary phases were employed: silica, octadecyl (C₁₈), propylamino (NH₂), and polystyrene-divinyl benzene (PRP). Without modifier the range of basicities which could be eluted increased in the order of silica < PRP < C₁₈ = NH₂. Chromatographic peak shapes and selectivity were much better with propylamino column. Different aromatic amines and azaarenes were successfully separated on both analytical scale and microbore propylamino bonded phase packed columns with 100% supercritical CO₂. Separation is compared with both reversed phase and normal phase high performance liquid chromatography (HPLC). The retention mechanism study for these aromatic amines and azaarenes shows that the elution order not only depends on basicity and steric hindrance, but also on the solubility of the solute in CO₂. New cross-linked cyanopropyl and phenyl bonded phases are studied as stationary phases for packed column SFC, as well as for separation of nitrogen-containing compounds. The cross-linked bonded phase impedes access to uncapped silanol sites, thereby giving rise to better peak shapes, and more rapid elution without the necessity of a polar modifier in the mobile phase. Experiments both at elevated temperature and in the presence of methanol modifier revealed that there is no short or long term deleterious effect on the column. The separation of model mixtures of nitrated diphenylamine and nitrated anilines via SFC employing cyanopropyl packed and capillary columns is described. Peak identification and peak purity were performed by on-line Fourier transform infrared spectrometric detection. Supercritical CO₂ is employed with cyanopropyl packed columns for separation of non-polymeric components in double-base rocket propellants. Both supercritical CO₂ and CH₂Cl₂ were compared as a solvent for extraction of nonpolymeric components in "good" and "bad" double-base propellant. Finally, twenty-four phenylthiohydantion amino acids (PTH-AA) have been rapidly and efficiently separated on a cyanopropyl packed column by gradient elution of supercritical CO₂ and tetramethyl ammonium hydroxide-modified methanol. Complete or partial resolution of 22 derivatives is observed with only valine co-eluting with norleucine and lysine co-eluting with asparagine. No modifier was required for elution of neutral PTH-AA's from the cross·linked stationary phase. The addition of base plays a major role in elution of acidic and basic PTH-AA's.
Ph. D.
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33

Teepakorn, Chalore. "Numerical simulation and experimental study of membrane chromatography for biomolecule separation". Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10299/document.

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Abstract (sommario):
La chromatographie membranaire est une alternative à la chromatographie classique sur résine basée sur le transport convectif des solutés à travers une membrane microporeuse plutôt que par le transport diffusif des solutés dans les particules de résines. Cette technique présente les avantages de diminuer les phénomènes de diffusion, de réduire les temps de séjour et les pertes de charge, et de permettre la purification rapide de quantités importantes de molécules. La chromatographie membranaire connaît un fort succès commercial. Une gamme importante de membranes chromatographiques mettant en jeu différents mécanismes de rétention (échange d’ions, affinité, etc.) et différentes géométries (feuille, spirale, etc.) est actuellement commercialisée. Malgré ce succès, différents aspects relatifs à la chromatographie membranaire restent mal connus. Cette thèse de doctorat se propose de répondre à certaines questions relatives à cette technique
Membrane chromatography (MC) is an alternative to traditional resin packed columns chromatography. The solute mass transport in the membrane occurs in convective through-pores rather than in stagnant fluid inside the pores of the resins particles, which is limited by the slow diffusive transport. MC offers the main advantage of reducing diffusion phenomena, shorter residence time and lowered pressures drops, and thus, facilitates rapid purification of large quantities of molecules. A wide range of chromatographic membranes involving different molecules retention mechanisms (ion exchange, affinity, etc...) is now commercialized. Despite their success, the influence of the geometry of the membrane chromatography devices remains relatively unexplored from a theoretical point of view. This doctoral thesis is aimed to clarify some ambiguous points related to this technique
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34

Jeong, Lena N. "Development of General Purpose Liquid Chromatography Simulator for the Exploration of Novel Liquid Chromatographic Strategies". VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/5079.

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The method development process in liquid chromatography (LC) involves optimization of a variety of method parameters including stationary phase chemistry, column temperature, initial and final mobile phase compositions, and gradient time when gradient mobile phases are used. Here, a general simulation program to predict the results (i.e., retention time, peak width and peak shape) of LC separations, with the ability to study various complex chromatographic conditions is described. The simulation program is based on the Craig distribution model where the column is divided into discrete distance (Δz) and time (Δt) segments in a grid and is based on parameterization with either the linear solvent strength or Neue-Kuss models for chromatographic retention. This algorithm is relatively simple to understand and produces results that agree well with closed form theory when available. The set of simulation programs allows for the use of any eluent composition profile (linear and nonlinear), any column temperature, any stationary phase composition (constant or non-constant), and any composition and shape of the injected sample profile. The latter addition to our program is particularly useful in characterizing the solvent mismatch effect in comprehensive two-dimensional liquid chromatography (2D-LC), in which there is a mismatch between the first dimension (1D) effluent and second dimension (2D) initial mobile phase composition. This solvent mismatch causes peak distortion and broadening. The use of simulations can provide a better understanding of this phenomenon and a guide for the method development for 2D-LC. Another development that is proposed to have a great impact on the enhancement of 2D-LC methods is the use of continuous stationary phase gradients. When using rapid mobile phase gradients in the second dimension separation with diode array detection (DAD), refractive index changes cause large backgrounds such as an injection ridge (from solvent mismatch) and sloping baselines which can be problematic for achieving accurate quantitation. Use of a stationary phase gradient may enable the use of an isocratic mobile phase in the 2D, thus minimizing these background signals. Finally, our simulator can be used as an educational tool. Unlike commercially available simulators, our program can capture the evolution of the chromatogram in the form of movies and/or snapshots of the analyte distribution over time and/or distance to facilitate a better understanding of the separation process under complicated circumstances. We plan to make this simulation program publically available to all chromatographers and educators to aid in more efficient method development and chromatographic training.
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35

Williamson, Yuping. "Studies on concentration overload in micellar electrokinetic chromatography and peak overlap in gas chromatography /". Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1240704131&sid=7&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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36

Li, Zhiguo. "High-performance liquid chromatography analysis of fatty acids and mathematical modeling of liquid chromatography". Ohio : Ohio University, 2001. http://www.ohiolink.edu/etd/view.cgi?ohiou1179157379.

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37

Shapiro, M. "Design and characterisation of microlitre scale chromatography for the comparison with preparative scale chromatography". Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/18783/.

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Abstract (sommario):
Ion exchange chromatography is a ubiquitous unit operation within bioprocessing. There are a large number of ion exchange resins, however there is limited time and material available for a full assessment. The work reported is primarily concerned with the microfluidic scale down of process chromatography. Microfluidic technologies offer the potential to investigate events occurring within the bed (such as adsorption profiles) that would be more difficult to observe in larger systems. In addition, the devices may be used for the investigation of adsorbent type, buffer type, pH, flowrate etc. by employing parallel architecture to increase throughput. To facilitate the objectives described above, the fluidic handling and detection system was characterised. For the packing of microfluidic chips to be relevant for comparison, it was necessary to analyse the quality of the packing. Plate calculations combined with 3 dimensional imaging using confocal microscopy were used. According to the plate calculations, the microfluidic column was poorly packed, however the 3 dimensional imaging allowed a full assessment of the packing contained within the microfluidic column. Both frontal and elution chromatography results were generated using the microfluidic chip. Useful breakthrough curves using lysozyme were produced which compared well with both laboratory scale curves and previously published data. The general rate model was then used to understand whether the microfluidic column's breakthrough curves could simulate laboratory scale curves. The results produced showed that a new model was required to further develop the simulation. Separations were achieved using the egg white protein system containing 3 proteins. Microfluidic column separations were achieved using both step and linear gradients. These separations compared favourably with laboratory scale separations, although the use of linear gradients would require further work, as they proved challenging to reproduce at the microfluidic scale. However, the separation generated was similar to the laboratory scale.
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38

Gadgil, William Himanshu S. "Advances in DNA Affinity Chromatography". View the abstract Download the full-text PDF version, 2001. http://etd.utmem.edu/ABSTRACTS/2001-001-gadgil-index.htm.

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Thesis (Ph.D.)--University of Tennessee Health Science Center, 2001.
Title from title page screen (April 10, 2008). Research advisor: Harry W. Jarrett, Ph.D. Document formatted into pages (xv, 162 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 152-162).
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39

Wang, Mei. "Chromatography with no stationary phase /". Full text available from ProQuest UM Digital Dissertations, 2006. http://0-proquest.umi.com.umiss.lib.olemiss.edu/pqdweb?index=5&did=1383464751&SrchMode=1&sid=4&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1217274375&clientId=22256.

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40

Burton, Nicolas Paul. "Novel ligands for affinity chromatography". Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359769.

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41

Perkins, John Robert. "Supercritical fluid chromatography/mass spectrometry". Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375969.

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42

Al-Othmany, Dheya Shuja'a. "Tritium enrichment by gas chromatography". Thesis, University of Aberdeen, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240675.

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In the studies related to trace analysis in meteorology, hydrology, medical and clinical research, the measurement and monitoring of tritium released from nuclear facilities and its health physics aspects on human and the environment are of growing importance. The techniques employed currently for the enrichment of tritium are carried out using large samples and require long periods of operation (7 days or more) to obtain the enriched tritium sample. In the present investigation, a laboratory scale chromatography based system was designed, constructed and commissioned successfully to collect enriched tritiated water samples which were then counted to determine the levels of activity. The total time taken to conduct the complete enrichment procedure and counting of the collected samples was less than one working day. This system also showed the capability of enriching quantities of water samples as small as 20 ml. This was about ten times less than required in the conventional enrichment techniques. Extensive efforts were made to attain optimum operational, reproducible and efficient measurements of tritium enrichment for quantitative analysis. The developed experimental technique involved injecting a known volume of water into a preheated furnace to react with magnesium turnings, in the presence of a carrier gas, to produce the hydrogen isotopes. These isotopes were separated using the principles of chromatography. Liquid scintillation counting method was employed to determine the activity of the collected samples. Two gases, nitrogen and helium, were utilized as the carrier gases during this investigation. Best values of enrichment were obtained with the use of nitrogen as a carrier gas, but the samples collected were difficult to count due to the formation of ammonia with consequent chemical complications.
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43

Santori, Fabio. "Lectin affinity chromatography of monosaccharides". Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760807.

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44

Qian, Jianing. "Affinity chromatography of camelid antibodies". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610171.

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45

Chienthavorn, Orapin. "Detection in superheated water chromatography". Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/32394.

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Abstract (sommario):
Superheated water has been used successfully as an eluent in liquid chromatography and has been coupled to various modes of detection, ultraviolet (UV), fluorescence, and nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). A number of compounds were examined on poly(styrene-divinylbenzene) (PS-OVB), polybutadiene (PBO), and octadecylsilyl bonded silica (OOS) column with isothermal and temperature programmes.
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46

McGill, Robert Andrew. "Physicochemical measurements by gas chromatography". Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/847792/.

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First the method of gas-liquid chromatography (GLC) has been used to obtain partition coefficients, K, at infinite dilution on polymeric and non-polymeric phases. About 30-40 solutes were studied per stationary phase. Secondly the method of gas-solid chromatography has been used to obtain adsorption isotherms for a series of adsorbents by the technique of elution by characteristic point (ECP). A single injection of a gas or vapour suffices to obtain the isotherm, and then the limiting Henry's law constant, Kh, for adsorption at low surface coverage. About 20-30 solutes were studied per adsorbent. Experiments were carried out at several levels of relative humidity (RH) 0%, 31% and 53%. The solute compounds used were chosen so as to have a wide range of properties such as polarity (pi*2), hydrogen-bond acidity (alpha[H]2), and hydrogen-bond basicity (beta[H]2). The results as log partition coefficients or -log Henry's constants were analysed by multiple linear regression analysis using equations such as: -LogK[H] or LogK = SPo + s.pi* 2 + a.alpha[H]2 + b.beta[H]2 + 1. LogL[18] where L[18] is the solute Ostwald absorption coefficient on n-hexadecane. In this way, the selectivity of the liquid polymeric phase or solid adsorbent towards classes of compound was investigated and equations for the prediction of further values of LogK or LogK[H] formulated. In parallel with the measurement of partition coefficients on liquid polymeric phases by GLC in this work, partition coefficients for the polymers have been determined using surface acoustic wave (SAW) devices by coworkers at the Naval Research Laboratory, Washington. The results for a series of 8-9 solutes in six polymeric phases show that partition coefficients and patterns of responses predicted through GLC experiments are the same as those found experimentally using coated SAW devices. Hence GLC can be used to evaluate possible coating materials, and by the technique of multiple linear regression analysis, to predict SAW responses for a multitude of vapours.
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47

Polite, Lee Nicholas. "Studies in ion exchange chromatography". Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/54338.

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This dissertation investigates three major problems in IC, ranging from the practical to the theoretical. The first is of interest to the field of quantitative analysis. Since ion chromatography is primarily a quantitative technique, the linear range of the detector is of particular interest. The linear range was determined to be nearly five orders of magnitude for several common ions. The probes used were fluoride, chloride, sulfate, sodium, and potassium with concentrations ranging from 10 ppb to 1000 ppm. This portion of the dissertation describes the first attempt made to elucidate the linear detection range in ion chromatography using micro-membrane suppression. The Iinearity experiments demonstrate the versatility of ion chromatography with respect to quantifiable concentrations. However, a major problem is encountered when attempting to determine a trace ion concentration in the presence of a high concentration of a similarly charged ion (matrix ion). The second part of this dissertation offers a solution to this problem. In ion chromatography, the large excess of a matrix ion affects not only the ions expected in that region of the chromatogram, but also destroys the chromatographic exchange process. One objective of this study was to develop a rapid quantitative method to determine 5 ppm chloride in the presence of 100,000 ppm sulfate. A standard anion exchange column will completely lose resolution between chloride and sulfate at a sulfate concentration of approximately 2500 ppm. The apparatus designed and built by the author uses two analytical ion—exchange columns coupled in series by a high pressure switching valve. ln order to complete the system, the author designed and built y a high pressure conductivity detector cell to monitor the conductivity of the effluent from the first column. The system works by overloading the first column and then allowing the effluent to pass onto the second column. When the trace chloride in on the second column, the first column is switched out of line. This process allows the trace chloride to be separated from the residual sulfate. The column switching study brought to light several theoretical questions about the inner workings of the packing materials used in ion chromatography. These questions include the effects that flow rate and temperature have on capacity and efficiency in ion chromatography separations. Using chloride and sulfate as probes, the chromatographic efficiency was shown to decrease from 30° to 60° C. Even more surprising was the result that sulfate retention increased with increasing temperature while chloride retention decreased under the same conditions. Detailed studies as well as possible explanations are included in the third part of this dissertation.
Ph. D.
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48

Andersson, David. "Simulation Testbed for Liquid Chromatography". Thesis, Umeå universitet, Institutionen för fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-185024.

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The stlc package is proposed as a tool for simulation of liquid chromatography by implementing several lumped kinetic models which combine diffusive mass  transport and adsorption isotherm equations. The purpose of the package is to provide computationally efficient approximations to the general rate model of chromatography. Orthogonal collocation is used to discretize the spatial domain and the resulting system of ordinary differential equations is evaluated by one of several solvers made available in the package.  Comparisons between numerical and analytical Laplace domain solutions for values of mass transfer coefficient, k, ranging from 0 to 1000 and lumped dispersion constant values, DL,from 10-5 to 10-2 are presented. Analytical results were approximated to an L1 error in the range 10-5 to 10-3 with a maximum evaluation time of 0.27s for 100 grid points. The breakthrough curves of the analytical solution are accurately recreated indicating a correct implementation. Variations in accuracy can be partly attributed to  oscillations induced by steep gradients in the solution. The oscillations are reduced by the addition further points to the spatial grid. The package is implemented in Python using    minimal dependencies and can produce approximations with short evaluation times. The Python programming language is dynamically typed and uses automatic memory management, properties  which can improve productivity and be beneficial to research applications. The addition of this package to the extensive Python ecosystem of libraries can potentially aid future       developments in chromatography.
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49

Maketon, Supachai. "Methods Development for Ion Chromatography". Thesis, North Texas State University, 1986. https://digital.library.unt.edu/ark:/67531/metadc330927/.

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Abstract (sommario):
Ion chromatography (IC) as developed by Small et. al. in 1975 has become an efficient and reliable analytical technique for simultaneous analysis of multiple ions in solution. The principle requirement prior to use the IC for an analysis is sample preparation; these include sample decomposition, solvent extraction, and trapping in case the target element is in the gas phase, etc. Solvent extractions for fluoride, chloride, sodium, ammonium, and potassium ions which are soluble in soils are described. Sample decompositions include silicate rocks using hydrofluoric acid for the determination of phosphorus; organic pesticides using lithium fusion technique for the determination of halide and cyanide ions are also described. After these sample preparation techniques, the aqueous solutions obtained were analyzed on the ion chromatograph for the analyses of the anions and cations mentioned above. Recovery and reproducibility of each technique is in general quite good and the comparison between the results obtained from the IC method and other instrumentation are given.
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50

Otsuka, Koji. "FUNDAMENTAL STUDIES ON ELECTROKINETICK CHROMATOGRAPHY". Kyoto University, 1986. http://hdl.handle.net/2433/74676.

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