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Development and Validation of HPLC Methods for Analytical and Preparative PurposesLindholm, Johan January 2004 (has links)
<p>This thesis concerns the development and validation of high performance liquid chromatography (HPLC) methods aimed for two industrially important areas: (i) analysis of biotechnological synthesis and (ii) determination of adsorption isotherm parameters. There is today a lack of detailed recommendations for analytical procedures in the field of biotechnological production of drugs. Therefore, guidelines were given for analytical development and validation in this field; the production of 9α-hydroxyprogesterone was used as model. In addition, a rapid method using HPLC coupled with diode-array-detection (DAD) and mass spectrometry (MS), was developed for the preliminary identification and quantification of the product. In addition, requirements and recommendations were developed for the selection of the internal standard and for its inclusion in the process liquid. By using this approach the precision and accuracy of the quantitative method were considerably improved. </p><p>Preparative chromatography is a powerful separation method for the purification of pure compounds from more or less complex sample mixtures. One such mixture can be the process liquid from a fermentation, another example can be a racemic mixture of compounds whose enantiomeric constituents must be isolated. Computer-assisted modeling can be used to optimize preparative chromatography. However, competitive adsorption isotherm parameters are required as input data for the computer simulations. In this thesis, a new injection technique, based on a firm theoretical basis, was developed for the peak perturbation (PP) method allowing the determination of binary competitive adsorption isotherm parameters from a broad concentration range. With the new method the determination of adsorption isotherm parameters from a quaternary mixture could be done for the first time. The profiles simulated with these parameters showed excellent agreement with the corresponding experimental profiles, validating the accuracy of the adsorption isotherm parameters derived by the new method.</p>
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Development and Validation of HPLC Methods for Analytical and Preparative PurposesLindholm, Johan January 2004 (has links)
This thesis concerns the development and validation of high performance liquid chromatography (HPLC) methods aimed for two industrially important areas: (i) analysis of biotechnological synthesis and (ii) determination of adsorption isotherm parameters. There is today a lack of detailed recommendations for analytical procedures in the field of biotechnological production of drugs. Therefore, guidelines were given for analytical development and validation in this field; the production of 9α-hydroxyprogesterone was used as model. In addition, a rapid method using HPLC coupled with diode-array-detection (DAD) and mass spectrometry (MS), was developed for the preliminary identification and quantification of the product. In addition, requirements and recommendations were developed for the selection of the internal standard and for its inclusion in the process liquid. By using this approach the precision and accuracy of the quantitative method were considerably improved. Preparative chromatography is a powerful separation method for the purification of pure compounds from more or less complex sample mixtures. One such mixture can be the process liquid from a fermentation, another example can be a racemic mixture of compounds whose enantiomeric constituents must be isolated. Computer-assisted modeling can be used to optimize preparative chromatography. However, competitive adsorption isotherm parameters are required as input data for the computer simulations. In this thesis, a new injection technique, based on a firm theoretical basis, was developed for the peak perturbation (PP) method allowing the determination of binary competitive adsorption isotherm parameters from a broad concentration range. With the new method the determination of adsorption isotherm parameters from a quaternary mixture could be done for the first time. The profiles simulated with these parameters showed excellent agreement with the corresponding experimental profiles, validating the accuracy of the adsorption isotherm parameters derived by the new method.
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Fiabilité de diodes laser de forte puissance 808 nm microassemblées pour des applications spatiales : approche expérimentale et modélisations par éléments finisRehioui, Othman Elmehdi 14 June 2011 (has links)
Ces travaux de thèse ont pour objectif de proposer une nouvelle technique de caractérisation électro-optique de barrettes de diodes Laser de puissance (DLPs), au niveau émetteur individuel à partir d'un banc dédié, utilisées pour le pompage optique à 808nm de système LIDAR en environnement spatial et en régime QCW. Après une étude métrologique fine, ils décrivent une méthodologie de sélection d'un indicateur précoce de défaillance potentielle et sa capacité à estimer la fiabilité de DLPs en conditions opérationnelles (> 109 impulsions à 100Hz/200µs). L’analyse de la dégradation des DLPs se base sur l'identification de signatures paramétriques de défaillance mises en lumière après une série de tests accélérés ciblés et relatives à l'évolution de la puissance optique, du spectre optique (λmax) et du degré de polarisation (DOP) de chaque émetteur de la barrette. Nous montrons également la forte complémentarité entre la mesure du DOP par électroluminescence et par photoluminescence et nous proposons une méthodologie de sélection précoce des émetteurs en considérant leur localisation dans le plan (λmax, DOP). Ces études expérimentales, confortées par des simulations thermiques et mécaniques par éléments finis en introduisant un grand nombre de paramètres technologiques, ont permis de quantifier les niveaux de contraintes résiduelles dans les DLPs en fonction de différentes configurations d'assemblage et d'établir un lien avec leur fiabilité intrinsèque. / This thesis work aimed to propose a new methodology for electro-optical characterization ofQCW laser diodes array (LDA) at emitter level by using a dedicated test bench. After detailedmetrological study, a methodology for selecting an early failure indicator and its ability to assess theLDA reliability in operational conditions (> 109 Shots at 100Hz/200μs) has been described. The LDAdegradation analysis were based on identification of parametric failure signatures highlighted after aset of accelerated tests and have been focused on the evolution of optical power, optical spectrum(λmax) and the degree of polarization (DOP) of each emitter on the LDA. We also explain the strongcomplementarity between the measured DOP of photoluminescence and the DOP ofelectroluminescence and a methodology for early selection of emitters have been proposed by takinginto account their location in the plane (λmax, DOP). These experimental studies were comforted bythermal and mechanical finite element simulations, by introducing several technological parameters inorder to quantify levels of induced mechanical stresses in LDA under different assemblyconfigurations and to establish the link with their intrinsic reliability.
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Multivariate spectroscopic methods for the analysis of solutionsWiberg, Kent January 2004 (has links)
<p>In this thesis some multivariate spectroscopic methods for the analysis of solutions are proposed. Spectroscopy and multivariate data analysis form a powerful combination for obtaining both quantitative and qualitative information and it is shown how spectroscopic techniques in combination with chemometric data evaluation can be used to obtain rapid, simple and efficient analytical methods. These spectroscopic methods consisting of spectroscopic analysis, a high level of automation and chemometric data evaluation can lead to analytical methods with a high analytical capacity, and for these methods, the term high-capacity analysis (HCA) is suggested. It is further shown how chemometric evaluation of the multivariate data in chromatographic analyses decreases the need for baseline separation. </p><p>The thesis is based on six papers and the chemometric tools used are experimental design, principal component analysis (PCA), soft independent modelling of class analogy (SIMCA), partial least squares regression (PLS) and parallel factor analysis (PARAFAC). The analytical techniques utilised are scanning ultraviolet-visible (UV-Vis) spectroscopy, diode array detection (DAD) used in non-column chromatographic diode array UV spectroscopy, high-performance liquid chromatography with diode array detection (HPLC-DAD) and fluorescence spectroscopy. The methods proposed are exemplified in the analysis of pharmaceutical solutions and serum proteins.</p><p>In Paper I a method is proposed for the determination of the content and identity of the active compound in pharmaceutical solutions by means of UV-Vis spectroscopy, orthogonal signal correction and multivariate calibration with PLS and SIMCA classification. Paper II proposes a new method for the rapid determination of pharmaceutical solutions by the use of non-column chromatographic diode array UV spectroscopy, i.e. a conventional HPLC-DAD system without any chromatographic column connected. In Paper III an investigation is made of the ability of a control sample, of known content and identity to diagnose and correct errors in multivariate predictions something that together with use of multivariate residuals can make it possible to use the same calibration model over time. In Paper IV a method is proposed for simultaneous determination of serum proteins with fluorescence spectroscopy and multivariate calibration. Paper V proposes a method for the determination of chromatographic peak purity by means of PCA of HPLC-DAD data. In Paper VI PARAFAC is applied for the decomposition of DAD data of some partially separated peaks into the pure chromatographic, spectral and concentration profiles. </p>
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Multivariate spectroscopic methods for the analysis of solutionsWiberg, Kent January 2004 (has links)
In this thesis some multivariate spectroscopic methods for the analysis of solutions are proposed. Spectroscopy and multivariate data analysis form a powerful combination for obtaining both quantitative and qualitative information and it is shown how spectroscopic techniques in combination with chemometric data evaluation can be used to obtain rapid, simple and efficient analytical methods. These spectroscopic methods consisting of spectroscopic analysis, a high level of automation and chemometric data evaluation can lead to analytical methods with a high analytical capacity, and for these methods, the term high-capacity analysis (HCA) is suggested. It is further shown how chemometric evaluation of the multivariate data in chromatographic analyses decreases the need for baseline separation. The thesis is based on six papers and the chemometric tools used are experimental design, principal component analysis (PCA), soft independent modelling of class analogy (SIMCA), partial least squares regression (PLS) and parallel factor analysis (PARAFAC). The analytical techniques utilised are scanning ultraviolet-visible (UV-Vis) spectroscopy, diode array detection (DAD) used in non-column chromatographic diode array UV spectroscopy, high-performance liquid chromatography with diode array detection (HPLC-DAD) and fluorescence spectroscopy. The methods proposed are exemplified in the analysis of pharmaceutical solutions and serum proteins. In Paper I a method is proposed for the determination of the content and identity of the active compound in pharmaceutical solutions by means of UV-Vis spectroscopy, orthogonal signal correction and multivariate calibration with PLS and SIMCA classification. Paper II proposes a new method for the rapid determination of pharmaceutical solutions by the use of non-column chromatographic diode array UV spectroscopy, i.e. a conventional HPLC-DAD system without any chromatographic column connected. In Paper III an investigation is made of the ability of a control sample, of known content and identity to diagnose and correct errors in multivariate predictions something that together with use of multivariate residuals can make it possible to use the same calibration model over time. In Paper IV a method is proposed for simultaneous determination of serum proteins with fluorescence spectroscopy and multivariate calibration. Paper V proposes a method for the determination of chromatographic peak purity by means of PCA of HPLC-DAD data. In Paper VI PARAFAC is applied for the decomposition of DAD data of some partially separated peaks into the pure chromatographic, spectral and concentration profiles.
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Aufbau und Anwendung einer Methode zur Identifizierung und Quantifizierung von Giften und deren Metaboliten in Blut und Haaren in der Systematischen Toxikologischen Analyse mittels Flüssigchromatographie-Quadrupol-Flugzeitmassenspektrometrie-Kopplung (LC-QTOF-MS)Broecker, Sebastian 15 February 2012 (has links)
Die Systematische Toxikologische Analyse (STA) stellt auf Grund der großen Vielfalt und der ständigen Zunahme an toxikologisch relevanten Substanzen eine der größten Herausforderungen in der chemischen Analyse dar. In der vorliegenden Arbeit wurde daher die Eignung der Flüssigchromatographie in Kombination mit der Hybrid-Quadrupol-Flugzeitmassenspektrometrie (LC-QTOF-MS) für diesen Zweck untersucht. Dazu wurden eine Datenbank mit über 7360 und eine CID-Spektrenbibliothek mit mehr als 2720 toxikologisch relevanten Substanzen erstellt und geeignete Probenvorbereitungsmethoden entwickelt. Die Erprobung der Methoden erfolgte an dotierten Blut- und Haarproben. Hierbei zeigte sich, dass die Analyse im Auto-MS/MS-Modus (Messzyklen von MS- und MS/MS-Spektren) eine Identifizierung basischer Substanzen mittels CID-Spektren zwischen 0,5 und 2 ng/ml im Blut ermöglichte. Die Nachweisgrenzen der für 24 Wirkstoffe validierten Methode in Haaren lagen bei 3 bis 15 pg/mg. Die Eignung der LC-QTOF-MS zur STA von Haarproben wurde an 30 Drogentodesfällen und 60 Todesfällen mit bekannter chronischer Medikamenteneinnahme zu Lebzeiten sowie an 77 Blutproben nachgewiesen. Für die Suche nach Metaboliten wurde ein Metaboliten-Tool entwickelt. In der praktischen Anwendung auf Datenfiles von Blut- und Haarproben erwies sich das Tool als wertvolles Hilfsmittel zur Identifizierung unbekannter Peaks und zur Bestätigung von Suchergebnissen in der Datenbank. Zur automatischen Konzentrationsabschätzung identifizierter Substanzen wurde ein Tool „Estimate Concentration“ geschaffen. Die Überprüfung des Verfahrens an realen Blut- und Haarproben durch Vergleich mit HPLC-DAD- und GC-MS-Ergebnissen wies eine gute Übereinstimmung der Konzentrationen auf. Insgesamt zeigten die Untersuchungen, dass die LC-QTOF-MS zurzeit die am besten geeignete Methode für die STA darstellt. Auch bei einem erst später aufkommenden Verdacht kann eine gezielte Suche in dem bereits gemessenen Datenfile durchgeführt werden. / Due to the large variety and the steady increase of toxicologically relevant substances, systematic toxicological analysis (STA) is one of the most difficult tasks in analytical chemistry and, therefore, a steady topic of research and methodical improvement. For this reason, the suitability of liquid chromatography in combination with hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) for STA was investigated. For this purpose, a database of more than 7360 and a CID spectra library of more than 2720 toxicologically relevant substances and suitable methods for sample preparation were developed. The application was evaluated at spiked blood and hair samples. It was found that the analysis in Auto-MS/MS mode (alternating measurement cycles of MS and MS/MS spectra) allowed substance identification in blood using CID spectra between 0.5 and 2 ng/ml for basic substances. The detection limits of the validated method in hair ranged from 3 to 15 pg/mg for 24 drugs. The suitability of LC-QTOF-MS for STA was tested for hair samples from 30 drug-related death cases and from 60 death cases with known chronic medication as well as for 77 blood samples. For the search of metabolites, a metabolite tool was developed. In the practical application to data files from blood and hair samples, the tool proved to be very helpful for identification of unknown peaks and for confirmation of results obtained only from the database without CID spectra. A tool "Estimate Concentration" was created for automatic estimation of concentrations of identified substances. The application to real blood and hair samples and the comparison of the concentrations with results from HPLC-DAD and GC-MS showed good agreement. Overall, these investigations showed that LC-QTOF-MS is currently the most favorable method for STA. Because of the comprehensive registration of all substances in a sample, the data files can be checked for the presence of certain poisons even later without new measurements.
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