Dissertations / Theses on the topic 'Dispersion capillaire'

L'étude du phénomène de dispersion hydrodynamique dans les aquifères est très souvent rendue complexe par la présence d'hétérogénéités, ce problème bien connu des géophysiciens intervient dans de nombreux domaines, tels que la récupération du pétrole, le stockage de déchets, la propagation de polluants ou l'hydrogéologie. L'objectif de cette thèse est d'étudier ce phénomène sous les effets des forces capillaires et gravitaires, ainsi qu'identifier explicitement le tenseur de dispersion à l'aide d'une technique de changement d'échelle par l'homogénéisation. Les effets de forces capillaires et gravitaires sont pris en compte. Les simulations numériques permettent de valider la théorie
The study of the hydrodynamic phenomenon of dispersion in the aquifers is very often made complex by the presence of the heterogeneities. This well-known problem of the geophysicists intervenes in many fields such as the recovery of oil, the storages of waste, the propagation of pollutants or hydrogeology. The objective of this thesis is to study this phenomenon and to identify the tensor of dispersion explicitly using a technique of homogenisation. The gravity effects and capillary pressure are taken in consideration. Numerical simulations validate the results

L’objectif est de construire le modèle homogénéisé d’un écoulement diphasique en milieu poreux et fracturé, en mettant en évidence le phénomène de mélange dynamique (mixing) entre les phases, provoqué par l’hétérogénéité du milieu. L’attention est concentrée sur l’influence de la capillarité. L’homogénéisation à double échelle a été appliquée. Le mixing se manifeste sous forme de la dispersion hydrodynamique et de l’advection renormalisée. Le tenseur de dispersion, déterminé à travers le problème cellulaire, est une fonction non linéaire de la saturation, vitesse d’écoulement, rapport de viscosité et du nombre capillaire. Pour les milieux fracturés, une méthode streamline configurations a été avancée pour le cas diphasique. Elle permet d’obtenir la dispersion et la perméabilité effective sous forme analytique pour des réseaux de fracture périodiques, ou semi-analytique pour des réseaux aléatoires. La simulation d’un déplacement diphasique à la base du nouveau modèle a été réalisée
The objective of the thesis is to develop the homogenized model of a two-phase flow through a porous and fractured medium by highlighting the dynamic mixing between the phases, caused by the medium heterogeneity. Attention is focused on the influence of the capillarity. The two-scale homogenization is applied. The mixing is manifested in form of the hydrodynamic dispersion and renormalized advection. The dispersion tensor, determined by the cell problem, is a nonlinear function of saturation, flow velocity, viscosity ratio and capillary number. For a fractured medium the method of streamline configurations was advanced for a two- phase case. This method enables to obtain the dispersion tensor and the effective permeability in analytical form for periodic fractured networks or in semi-analytical form for random networks. The simulation of two- phase displacement based on the new model is performed

Le sang est une suspension dense en globules rouges (GR, environ 50% du volume) qui sont des cellules très déformables, leur principal fonction est le transport de l'oxygène des poumons vers les organes. Cet échange gazeux dans les organes fait intervenir un réseau ramifié de capillaires sanguins où de nombreux phénomènes couplés créent un écoulement complexe (organisation des globules rouges dans l'écoulement, rhéologie, séparation de l'écoulement aux intersections). Un paramètre essentiel de la microcirculation est le temps de transit des GRs dans un organe, ce temps de transit est une limitation à la diffusion et à la disponibilité en oxygène et peut conduire à une désaturation non-optimal avant de quitter le réseau microcirculatoire pour rejoindre le système veineux. Suivant les propriétés mécaniques des GRs qui peuvent être modifiés par des pathologies et leur concentration, leur temps de transit peut varier dans de larges proportions, et peut ainsi être très dispersé autour de la valeur moyenne pour le même échantillon : certains GRs sont plus rapides que d'autres. Les mécanismes en jeu font intervenir la rhéologie du sang (la viscosité apparente varie en fonction du confinement des capillaires, de la rigidité des globules rouges) et la migration hydrodynamique des globules rouges due à l'interaction entre les GRs et les parois du vaisseaux. Ce phénomène de dispersion peut être qualitativement relié au phénomène connu de la dispersion de Taylor d'une solution dans un canal et est aussi connu dans le cas des suspensions colloïdales.Des simulations numériques dans l'équipe d'accueil ont montré que la dispersion moyenne de la vitesse de transit des GRs dans un réseau microcirculatoire était très sensible aux propriétés mécaniques des GRs et à leur dispersion transversale dans le réseau. Cette thèse propose ainsi d'explorer plusieurs aspects de la dispersion des globules rouges dans différentes situations modèles. Le premier chapitre sera dédié à l'étude de la migration transversale des globules rouges des parois vers le centre du canal en milieu très dilué, en effet ce phénomène joue un rôle très important dans la mise en place d'une couche de déplétion au niveau des parois. Le second chapitre sera dédié à l'étude de la dynamique de structuration observé dans les écoulements, l'idée est de mesure l'évolution du profil de concentration des globules rouges le long d'un canal rectiligne après une intersection en T. Le dernier chapitre s'intéressera à l'évolution d'un bolus de globules rouges dans un canal pseudo-2D rectiligne, ça dynamique permettre d’observer l'influence des propriétés mécaniques des globules rouges et de la concentration sur la dispersion des temps de transit
Blood is a dense suspension of red blood cells (RBCs, about 50% in volume) which are highly deformable cells whose function is oxygen transport from lungs to organs. This gas exchange function in organs involves flow in a dense and ramified capillary network where several coupled phenomena lead to a complex traffic flow (organisation of RBCs in flow, rheology, separation at bifurcations). An essential parameter of microcirculation is the transit time of RBCs in an organ, that can be a limitation to diffusion and disponibility of oxygen and lead to non-optimal desaturation before leaving the microvascular network to reach the veinous system. Depending on mechanical properties of RBCs that can be modified by pathologies, and their en concentration, their transit time can vary in large proportions, and also be quite dispersed around the mean value for the same sample : some RBCs are faster than others. The mechanisms involved are the rheology of blood (the apparent viscosity varies with confinement in capillaries and RBC rigidity), and the hydrodynamic migration dispersion of RBCs due to interactions between cells and with vessel walls. This phenomenon can be qualitatively related to the well known phenomenon of Taylor dispersion of a solute in a channel and is also known for colloidal suspensions.Numerical simulations in the host team have revealed that the dispersion of average transit velocities of RBCs in a microcirculatory network was very sensitive to the mechanical properties of cells, as well as their transverse spatial dispersion in the network. This thesis proposes to explore several aspects of RBC dispersion in different model situations. The first chapter will be dedicated to the study of the transverse migration of RBCs from the walls towards the center of the canal in a very diluted medium, in fact this phenomenon plays a very important role in the establishment of a depletion layer at the walls. The second chapter will be dedicated to the study of structuration dynamics observed in flows, the idea is to measure the evolution of the concentration profile of RBCs along a rectilinear canal after a T intersection. chapter will focus on the evolution of a bolus of RBCs in a rectilinear pseudo-2D channel, it dynamic to observe the influence of the mechanical properties of red blood cells and concentration on the dispersion of transit time

Until present, many researchers relied on the conventional plug flow dispersion models to analyse the concentration profiles obtained from the tracer injection experiments to evaluate the dispersion coefficients in packed beds. The Fickian concept in the limit of long time duration is assumed to be applicable and it implies that the mean-square displacement of the tracer profile is constant with time and the concentration profile is Gaussian. There were very few studies on identifying the conditions under which this assumption is valid and delineate the range of applicability of the existing plug flow dispersion models. If the time scales of a tracer injection experiment are not sufficient for a tracer to traverse the bed radius and sample the velocity variations, this could give rise to persisting non-Fickian transients where the mean-square displacement of the tracer profile is not constant with time and the concentration profile deviates from the normal Gaussian distribution. These transients cannot be predicted by the conventional plug dispersion models. An extended axial non-Fickian macroscopic dispersion model is derived to describe the transient development of a solute tracer when injected into a fluid flowing through a cylindrical packed bed or empty tube and some non-Fickian effects in the dispersion process. The flow profile in beds packed with uniform particles exhibits radial non-uniformity due to the oscillatory variation in porosity because of the wall confinement (wall effect). Compared with the axial plug flow dispersion model, the extended model contains time-dependent coefficients such as the transient axial dispersion coefficient and higher order derivatives (higher than second order) of the cross-sectionally averaged concentration. Including them provides some insight on non-Fickian transport in the dispersion process. The model provides time criteria on the basis that the effelongitudinal dispersion coefficient in the packed bed reaches its asymptotic value and the non-Fickian transients will die out. Some experimental conditions in the literature were checked by these criteria and found to be either marginally satisfied, or not satisfied at all, which indicates that the Fickian concept is not valid. The model results for tracer dispersion in cylindrical packed beds show that the longitudinal dispersion coefficient converges to its asymptotic value on a time scale proportional to R2/(DT) where R is the column radius and (DT) is the area averaged lateral dispersion coefficient. The extended model encouraged study of the consequences of the additional dispersion terms in other applications such as the pulse spread in the field of capillary column inverse gas chromatography (CCIGC). CCIGC is used to evaluate the solute-polymer diffusion coefficient Dp and the partition coefficient K at infinite dilute conditions. The tube geometry in CCIGC is more complex than the conventional Taylor dispersion problem due to the polymer coating on the inside of the capillary wall. The extended CCIGC model presented in this study has advantages over the previous models by including the effects of Taylor dispersion and higher order derivatives of the pulse area-averaged concentration. Taylor dispersion effect causes more pulse spread in the longitudinal direction and by not including it in the CCIGC regression models may cause a significant error in the measured Dp values. The extended CCIGC model provides for the first time criteria on capillary dimensions for the transient coefficients (multiplying the second and higher order derivatives) to become constant and for the non-Fickian effects associated with the higher order derivatives to be neglected. Model results show that Taylor dispersion effect has a significant effect on the elution profiles at high values of Dp and/or low values of gas diffusion coefficients Dg and it can be used to increase the sensitivity range of the previous CCIGC models at extremely low and high Dp values.

Le but de ce travail est de préciser les principaux paramètres conditionnant l'efficacité du lavage des pâtes écrues par déplacement. Une étude bibliographique a permis de montrer que l'efficacité du lavage d'un matelas fibreux dépendait essentiellement de sa consistance, de son épaisseur et de son état de structuration. L'état de structuration, lié à la floculation des fibres, ayant été peu étudié, nous nous sommes intéressés plus particulièrement à son influence. Des mesures de pertes de charge ont été effectuées pour évaluer la dégradation d'énergie subie par un fluide traversant un lit de fibres de viscose ou de pâte kraft écrue de résineux. La modélisation de ces pertes de pression à partir du modèle capillaire de Comiti et Renaud a montré les limites d'application de l'approche géométrique pour des matelas fibreux de porosités supérieures à 0,7. Un modèle particulaire fondé sur la notion d'écoulement autour d'objets immergés a donc été développé. Ce modèle représente précisément les pertes de pression dans les matelas fibreux pour des porosités supérieures à 0,84, quelle que soit la nature de l'écoulement: régime laminaire linéaire et non linéaire. En régime laminaire linéaire, il est applicable aux porosités supérieures à 0,69. Pour évaluer l'efficacité du lavage, des mesures de dispersion axiale d'un traceur ont été effectuées. Les résultats obtenus pour des lits de fibres de viscose ont souligné la spécificité du matelas fibreux. Ce sont des milieux très dispersifs pour lesquels la dispersion axiale se produit à une échelle très supérieure à celle de la particule. Les mesures effectuées sur des lits de pâte kraft écrue ainsi qu'une synthèse bibliographique ont permis de mieux cerner l'effet de l'état de structuration. A FAIBLE CONSISTANCE, LA PRESENCE DE FLOCS ENTRAINE UNE DIMINUTION DE L'EFFICACITE. A FORTE CONSISTANCE, LE PHENOMENE INVERSE EST CONSTATE. POUR LA PATE DEFLOCULEE, LA PERTE DE CHARGE SUBIE PAR LE FLUIDE EST TELLE QU'IL Y A CREATION DE PASSAGES PREFERENTIELS. LA PRESENCE DE FLOCS, ENTRAINANT UNE AUGMENTATION DE LA PERMEABILITE, REDUIT CES PASSAGES PREFERENTIELS ET LE PHENOMENE DE DISPERSION. LA LIMITE ENTRE CES DEUX ZONES CORRESPOND A UNE CONSISTANCE VOISINE DE 10%. CES DIFFERENCES CONFIRMENT, A POSTERIORI, LES DIFFERENCES OBSERVEES DANS LA CONDUITE DES LAVEURS INDUSTRIELS. CETTE IDENTIFICATION DES PHENOMENES MIS EN JEU DOIT PERMETTRE DE FIXER ULTERIEUREMENT LES CONDITIONS OPTIMALES POUR CHAQUE TYPE DE LAVEUR ET DE PATE TRAITEE

A microextração líquido-líquido dispersiva (DLLME) é uma técnica de preparo de amostra baseada no equilíbrio de distribuição do analito entre a fase doadora (amostra) e a fase aceptora (solvente orgânico) em um sistema ternário de solventes. Foi desenvolvida em 2006 por Rezaee e colaboradores para a determinação de hidrocarbonetos policíclicos aromáticos em amostras de água e por ser uma técnica muito recente,ainda é pouca explorada para o preparo de amostras biológicas. Portanto, o objetivo deste trabalho foi avaliar a DLLME como técnica para a extração da oxibutinina (OXY), fármaco usado para o tratamento da incontinência urinária, e da N-desetiloxibutinina (DEO), seu principal metabólito ativo, em amostras de urina. A análise da OXY e DEO foi realizada por eletroforese capilar (CE), utilizando um capilar de sílica fundida de 50 ?m de diâmetro interno, com comprimento efetivo de 36,5 cm, trietilamina 50 mmol/L, pH 3 como solução de eletrólito, tensão de30 kV, temperatura de 30°C e detecção em 204 nm. Nestas condições o tempo de migração da DEO foi de 7,12 min e da OXY foi de 7,42 min, com resolução de 3,1. O procedimento utilizado para preparo da amostra foi baseado na DLLME, utilizando 5 mL de urina,na qual foi adicionado 2,5% de NaCle cujo pH foi ajustado para 11. O solvente para a extração consistiu de uma mistura de 140 ?L de tetracloreto de carbono (solvente extrator) e 260 ?L de acetonitrila (solvente dispersor), que permaneceram em contato com a amostra pordois minutos. A avaliação das características de desempenho analítico apresentou faixa linear de 90-300 ng/mL para a OXY e 187,5-750ng/mL para a DEO. A recuperação absoluta foi de 71,4 e 60,9% e o limite de quantificação foi de 90 e 187,5 ng/mL para a OXY e DEO, respectivamente. Os estudos de precisão e exatidão apresentaram coeficientes de variação e erros relativos inferiores a 15% e as amostras foram estáveis nos estudos de estabilidade. Portanto, foi possível desenvolver um método rápido, fácil e confiável para analisar e quantificar a OXY e a DEO em amostras de urina por CE, usando a DLLME como técnica de preparo de amostra.
The dispersive liquid-liquid microextraction (DLLME) is a sample preparation technique based on the equilibrium distribution between an extraction solvent and a sample solution in a ternary solvent system. It was developed by Rezaee and co-workers in 2006 for the determination of polycyclic aromatic hydrocarbons in water samples. Until now, for being a very recent technique it was little explored for the analysis of drugs in biological fluids. Therefore, the aim of this work was to evaluate the DLLME as an extraction technique for oxybutynin (OXY), a drug used to treat urinary incontinence, and N-desethyloxybutynin (DEO), its main active metabolite in urine samples. The OXY and DEO\'s analysis was performed by capillary electrophoresis (CE) using a 50 ?m ID fused-silica capillary with an effective length of 36.5 cm with a photodiode array detector set at 204 nm. It made use of triethylamine 50 mmol/L pH 3 as background electrolyte, voltage of +30 kV and temperature of 30°C. Under these conditions the migration time were 7.12 minutes for DEO and 7.42 minutes for OXY, with a resolution of 3.1. The sample preparation procedure was based on DLLME and used 5 mL of urine samples whichionic strength was increased by the addition of 2.5% NaCland pH were adjusted to 11. The extraction mixture consisted of 140 ?L of carbon tetrachloride (extraction solvent) and 260 ?L of acetonitrile (disperser solvent), which remained in contact with the sample for two minutes. The analytical performance\'s evaluation presented linear range of 90-300 ng/mL for OXY and 187.5-750ng/mL for DEO. The absolute recovery were 71.4 and 60.9% and the limit of quantification were 90.0 and 187.5 ng/mL for OXY and DEO, respectively. The accuracy and precision studies showed coefficients of variation and errors below 15% and the samples were stable at stability studies. Therefore, it was possible to develop a fast, reliable and easy method to analyze and quantify OXY and DEO in urine samples by CE, using DLLME as a sample preparation technique.

A lamotrigina (LTG) é um fármaco pertencente à classe das feniltriazinas utilizado no tratamento de crises epilépticas generalizadas e focais e no tratamento adjunto da epilepsia refratária. Devido à alta variabilidade interindividual, às interações medicamentosas e aos efeitos adversos apresentados durante a administração da LTG, a monitorização terapêutica nos pacientes que fazem uso deste fármaco é necessária para ajuste de dose individual e evitar os efeitos adversos. Assim, o objetivo deste trabalho foi a avaliação de duas técnicas de microextração: a microextração em fase líquida com fibras ocas (HF-LPME) e a microextração líquido-líquido dispersiva (DLLME) para análise da lamotrigina em amostras de plasma de pacientes epilépticos. Primeiramente foram definidas as condições eletroforéticas: foi utilizado um capilar de sílica fundida de 75 ?m de diâmetro interno e 50 cm de comprimento efetivo. O eletrólito de corrida (BGE) foi composto por ácido 2-morfolinoetanosulfônico (MES), na concentração de 130 mmol L-1 e pH 5,0. As análises foram realizadas à temperatura de 20°C e tensão de 15 kV. A amostra foi injetada hidrodinamicamente (0,5 psi por 10 s) e a detecção foi feita em 214 nm. Nestas condições a LTG e o padrão interno (PI), lidocaína, puderam ser analisados em menos de 7 minutos. A HF-LPME foi avaliada no modo de 3 fases, usando 500 ?L de plasma e 3,5 mL de solução fosfato de sódio 50 mmol L-1 pH 9,0 como fase doadora. O solvente utilizado para impregnar a fibra foi o 1-octanol. Como fase aceptora foram utilizados 60 ?L de solução de ácido clorídrico pH 4,0. Para avaliação da DLLME, foi necessária uma etapa de pré-tratamento da amostra (500 ?L de plasma) com 1 mL de acetonitrila. Após isto, 1,3 mL do sobrenadante foram adicionados a 4 mL de solução fosfato de sódio 50 mmol L-1 pH 9,0 e 120 ?L de clorofórmio (solvente extrator) foram injetados nesta amostra aquosa e 165 ?L de fase sedimentada foram recuperados. As características de desempenho analítico para ambos os métodos foram avaliadas, sendo obtida linearidade na faixa de concentração plasmática de 1-20 ?g/mL e limite inferior de quantificação (LIQ) de 1 ?g mL-1. Os ensaios de precisão e exatidão apresentaram valores de acordo com os guias oficiais. Além disso, os métodos foram seletivos, não apresentaram efeito residual e as amostras foram estáveis. Os valores de recuperação foram de 54,3 e 23% para HF-LPME e DLLME, respectivamente. Os métodos validados foram aplicados com sucesso em amostras de plasma de pacientes epilépticos em tratamento com a LTG. Além disso, as duas técnicas foram comparadas e a HF-LPME apresentou vantagens em relação à DLLME, mostrando ser uma técnica promissora para análise de matrizes complexas, com reduzido consumo de solvente orgânico e possibilidade de automação.
Lamotrigine (LTG) is an antiepileptic drug, which belongs to the class of phenyltriazine that can be used in the treatment of new-onset and refractory epilepsy. Due to its high interindividual variability, drug interactions and the adverse effects presented during the LTG administration, therapeutic drug monitoring is very important to dose adjustment and to avoid toxicity effects. Thus, the goal of this study was to develop and validate two microextraction techniques: the hollow fiber liquid-phase microextraction (HF-LPME) and the dispersive liquid-liquid microextraction (DLLME) to analyze LTG in plasma samples of epileptic patients. First of all, the eletroforetic conditions were optimized. A fused-silica uncoated capillary with 75 ?m internal diameter, and 50 cm effective length was used. The 2-(N-morpholino)ethanesulfonic acid (MES) 130 mmol L-1 pH 5.0 was chosen as background electrolyte (BGE). The temperature and the voltage were kept constant at 20°C and 15 kV respectively. For sample injection, hydrodynamic injection mode was used, with a pressure of 0.5 psi applied for 10 s. The wavelength was set at 214 nm. Under final conditions, LTG and the internal standard (IS) lidocaine were analyzed in less than 7 minutes. HF-LPME was evaluated in the three phase mode. The analyte was extracted from 4.0 mL of a basic donor phase (composed of 500 ?L of plasma and 3.5 mL of sodium phosphate solution 50 mmol L-1 pH 9.0) into an organic phase composed of 1-octanol immobilized in the pores of the hollow fiber, and further into an acidic acceptor phase (hydrochloric acid solution pH 4.0) placed in the lumen of the fiber. To evaluate DLLME, the plasma samples were pretreated to remove the proteins, and 500 ?L of plasma sample was mixed with 1 mL of acetonitrile. After that, 1,3 mL of the upper layer was added to 4 mL of sodium phosphate solution 50 mmol L-1 pH 9.0, and 120 ?L of chloroform (extracting solvent) was rapidly injected in the aqueous sample and 165 ?L of the sedimented phase was collected. Under the optimized conditions, both methods were linear over the plasmatic concentration range of 1.0-20.0 ?g mL-1 and the lower limit of quantification (LLOQ) was 1.0 ?g mL-1. Both methods showed good precision, accuracy, selectivity to LTG, with no carryover and the samples were stable under the studied conditions. The recovery were 54,3 and 23% to HF-LPME and DLLME respectively. The validated methods were successfully applied for the quantification of LTG in plasma samples of epileptic patients. The techniques were compared and HF-LPME was more advantageous for being more suitable to analysis of complex matrices using small amount of organic solvent, and also can be automated.

Les matériaux à bande interdite électromagnétique (BIE), souvent nommés cristaux électromagnétiques, sont partie intégrante de la vaste famille des métamatériaux. Ils constituent l'objet d'études intensives depuis les deux dernières décennies suite au large éventail d'applications auxquelles ils donnent accès, souvent impossibles à obtenir avec des matériaux naturels, à l'instar de la réfraction négative. Généralement périodiques, ces structures sont caractérisées par trois paramètres principaux : la topologie du réseau, le pas du réseau, et la constante diélectrique de ses constituants. Leur périodicité permet l'ouverture de bandes de fréquence pour lesquelles la propagation des ondes est impossible, à l'image du miroir de Bragg. De plus, la forte anisotropie qui les caractérise permet le contrôle de la propagation des ondes électromagnétiques. Ils offrent ainsi des propriétés de filtrage à la fois spectral et spatial. Les applications courantes des cristaux photoniques et électromagnétiques incluent, sans toutefois y être limitées, les structures antennaires millimétriques et centimétriques, les surfaces haute impédance, les cavités résonantes, ou encore les différents dispositifs de guidage des ondes, basés sur les principes de réflexion interne totale, ou de cavités couplées. Bien que le domaine des applications technologiques potentielles s'accroisse rapidement, ces structures restent essentiellement passives. De ce fait, différents nouveaux concepts visant à leur conférer un caractère reconfigurable ont récemment émergés, que ce soit par le biais de matériaux ferroélectriques, de cristaux liquides, ou encore de composants actifs tels que les diodes ou les systèmes microélectromécaniques (MEMS), et plus récemment encore, les réseaux à base de microdécharges à plasma. Ce travail de thèse s'inscrit dans cette optique, et nous tentons d'apporter des solutions basées sur l'utilisation de capillaires à plasma pour permettre de reconfigurer, ou encore d'accorder dynamiquement ces structures, dans le domaine des microondes. En raison des pertes importantes et inévitables mises en jeu dans les plasmas, nous avons préféré limiter leur nombre en nous basant sur le contrôle de modes de défauts localisés plutôt que sur des réseaux complets de plasmas. Ces études ont été ménées à la fois de manière théoriques et expérimentales. Le travail se divise donc en deux parties. Dans un premier temps, nous développons les outils numériques adaptés à nos configurations, assez particulières puisqu'elles font intervenir des cylindres creux où règne un plasma. Nous nous basons d'abord, pour l'étude des réseaux infinis, sur la méthode des ondes planes. Souvent limitée au cas diélectrique, nous l'étendons aux cas de capillaires plasmas, et implémentons un outil complet pouvant traiter les cas classiques (tiges diélectriques, métalliques, et plasmas) comme des configurations plus particulières, tels que des cylindres bicouches impliquant deux matériaux différents. Dans le cas de réseaux finis, nous reprenons la méthode des matrices de diffraction, souvent limitée à des incidences planes et des cylindres pleins, que nous étendons au cas d'une incidence gaussienne d'abord, puis quelconque, dans le cas plus général de cylindres stratifiés. Nous implémentons également le cas des sources ponctuelles, donnant accès au calcul des densités locales d'état facilitant l'étude des modes de surface. La deuxième partie du travail concerne plutôt l'aspect expérimental de cette thèse. Des validations des outils précédents par la mesure sont d'abord présentées, basées sur l'étude de réseaux diélectriques, métalliques, et mixtes. Ces outils numériques sont ensuite mis à profit pour réaliser des structures potentielles commutables et accordables intégrant des capillaires à plasma. Une étude complète à la fois théorique et expérimentale est notamment menée sur des cavités résonantes à base de capillaires afin de dégager le type de technologie le plus adapté à la réalisation de dispositifs microondes (coupleurs, démultiplexeurs). La dernière partie concerne l'amélioration des dispositifs précédents, pour lesquels le couplage de l'onde incidente avec le réseau est assez faible, par le biais des modes de surface. Ce principe est ensuite utilisé pour créer une structure rayonnante directive dont la déviation angulaire du faisceau peut être contrôlée dynamiquement par le biais de capillaires plasma localisés à la surface du réseau
Electromagnetic bandgap structures, often called electromagnetic cristals, are parts of the wide metamaterials familly. They are the subject of intensive studies since the past two decades considering the wide range of applications to which they give access, often impossible to obtain with natural materials, like the negative refraction phenomenom. Generally periodic, these structures are caracterized by three main parameters: the array lattice type, its lattice constant, and the dielectric constant of its constituve materials. Their periodicity can give rise to frequency ranges over which the wave propagation is forbidden, as for Bragg mirors. Moreover, the high anisotropy which caracterizes these materials can allow the control of wave propagation outside these bangaps. They consequently offer both spatial and spectral filtering properties. Typical applications of photonic and electromagnetic cristals include, without being limited to, millimetric or centimetric radiative structures, high impedance surfaces, resonant cavities, or various wave guiding devices, based on total internal reflection or coupled cavities principles. Althought the field of potential technological applications grows rapidly, these structures still often remain essentially passive. As a result, various concepts aiming at bringing them reconfigurable properties have recently emerged, whether by means of ferroelectrics, liquid cristals, or localized components such as diodes or microelectromecanical systems (MEMS), and even more recently, microdischarge plasma arrays. This thesis work forms part from this perspective, and we try to bring solutions based on the use of plasma capillaries in order to achieve reconfigurable or dynamically tunable structures in the microwave regime. Because of the unavoidable losses that necessary come into play with the use of plasmas, we preffered to limit their use by working on localized defects control rather than on arrays entirely composed of plasmas. This studies were conducted both theoretically and experimantally. This work then organises itself in two main steps. Firstly, we developp numerical tools well suited to our configurations, rather special since they involve hollow cylinders where filled with plasma. We rely primarily on the plane wave expansion method for the case of infinite arrays, which we developp in details. Often limited to the dielectric case, we extend it to plasma capillaries arrays, and we implement a comprehensive tool that can handle conventionnal cases (arrays of dielectric, metallic, and plasma rods), but also more specific configurations such as bilayered cylinders involving two different materials for the coating and the core. For the finite lattice case, we make use of the scattering matrix method, which is often limited to plane wave incidences and simple cylinders. We extend it here for an incident gaussian beam, then for an arbitrary incident field, and in the more general case of stratified cylinders. We also implement the case of point sources, thus making possible the computation of the local density of states, which is of great interest in surface modes study for exemple. After these studies, we have at our disposal numerical models covering a very wide field of applications. The second part of the manuscript rather deals with the experimental aspects of this thesis work. Experimental validations of the previous numerical tools are first presented, which are based on dielectric, metallic, and hybrid arrays (containing both dielectric and metallic cylinders). The previously developped numerical tools are then used to design potential switchable and tunable structures involving plasma capillaries. A comprehensive study - both theoretical and experimental - is then conducted concerning plasma-based resonant cavities in order to identify the most suitable kind of technology for the realisation of microwave devices (couplers, demultiplexers). The last part focuses on the improvement of the previous dispositives, which suffer of a weak coupling with the incident wave, by means of surface modes. Those surface modes are then used to achieve a directive antenna whose scaning can dynamically be controlled by means of surface localised plasma capillaries

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Pró-Reitoria de Pós-Graduação (PROPG UNESP)
Este trabalho descreve o desenvolvimento de métodos analíticos ambientalmente mais amigáveis utilizando sistemas de screening e procedimentos de análise por injeção em fluxo para a detecção e quantificação de antibióticos, da classe das tetraciclinas, em amostras de medicamentos veterinários e alimentos de origem animal como leite bovino e suplementos de ovos. Os métodos desenvolvidos foram baseados na reação de acoplamento diazo obtida entre as tetraciclinas e o ácido p-sulfanílico diazotado em meio básico, resultando na formação de azo compostos com máximos de absorção em torno de 435 nm, permitindo determinar esses antibióticos por espectrofotometria. As condições analíticas foram otimizadas através de análise multivariada utilizando planejamentos experimentais fatoriais e o desempenho dos métodos propostos foi avaliado através de parâmetros como linearidade, efeito matriz, precisão, exatidão, limite de detecção, limite de quantificação, recuperação e estudo de interferências. O primeiro trabalho desenvolvido fez uso de um procedimento de injeção em fluxo contínuo para a rápida determinação de tetraciclinas em formulações veterinárias comerciais, visando maior eficiência no controle de qualidade na indústria farmacêutica. Na sequência, foi desenvolvido um método de screening mediante análise por injeção em fluxo empregando uma cela capilar de longo caminho óptico (LWCC) para a detecção de resíduos de tetraciclinas em amostras de leite bovino, sem a necessidade de passos de extração dispendiosos e demorados ou complicados tratamentos de amostras. Finalmente, um novo método de microextração líquido-líquido dispersiva assistida por ultrassom (US-DLLME) foi desenvolvido para a simples, rápida e eficiente extração de resíduos de tetraciclinas a partir de amostras de suplemento de ovos e, posterior análise por injeção em fluxo baseada em uma cela capilar de longo caminho óptico (LWCC), empregando um banho de aquecimento com controle de temperatura. Os métodos descritos apresentaram importantes características como simplicidade operacional, possibilidade de automação, rapidez e baixo custo das análises. Além disso, estes métodos seguiram os princípios da química verde, de modo que permitiram realizar determinações ambientalmente mais limpas, através da redução considerável do consumo de reagentes e amostras, evitando ou minimizando o emprego de solventes tóxicos. Também, os métodos desenvolvidos para a análise de resíduos mostraram excelente desempenho para aplicação no controle de qualidade dos produtos alimentares estudados na indústria alimentícia, a fim de proteger os consumidores.
This work describes the development of environmentally friendly analytical methods using screening systems and flow injection procedures for detection and quantification of tetracycline antibiotics in veterinary pharmaceuticals and animal-derived foods such as bovine milk and egg-based protein supplements. The developed methods were based on the diazo coupling reaction between the tetracyclines and diazotized p-sulfanilic acid in basic medium, resulting in the formation of azo compounds that present maximum absorption around 435 nm, which allows determining these antibiotics by spectrophotometry. The analytical conditions were optimized by means of multivariate analysis using factorial experimental designs. Performance of the proposed methods was assessed through parameters such as linearity, selectivity, precision, accuracy, detection limit, quantification limit, matrix effect and recovery. The first developed work used a continuous flow injection procedure for the rapid determination of tetracyclines in commercial veterinary formulations, aiming greater efficiency in quality control in the pharmaceutical industry. Thereafter, it was developed a screening method by flow injection analysis using a liquid waveguide capillary cell (LWCC) for detecting tetracyclines residues in bovine milk samples, without the need for expensive extraction steps that are time-consuming or complicated sample treatments. Finally, a new ultrasound-assisted dispersive liquid-liquid microextraction (US-DLLME) method was developed for simple, rapid, and efficient extraction of tetracyclines residues from egg supplement samples, followed by flow injection analysis based on a liquid waveguide capillary cell (LWCC), using a controlled temperature heating bath. The described methods presented important features such as operational simplicity, possibility of automation, quickness and low cost of the analysis. Furthermore, these methods followed the principles of green chemistry, making possible to perform environmentally cleaner determinations, due to the considerable reduction of reagents and samples consumption, avoiding or minimizing the use of toxic solvents. Besides, the methods developed for residues analysis showed excellent performance for application in the food industry for quality control of the studied food products in order to protect consumers.

Depuis plusieurs décennies, une importante activité scientifique se concentre sur la description numérique, théorique ou expérimentale de l'hydrodynamique des écoulements multiphasiques. Ces écoulements sont caractérisés par l'existence d'interfaces, et d'une force à l'interface, la tension superficielle, séparant généralement deux fluides non miscibles. Un cas d'étude dans ce contexte est le problème du drainage d'une unique goutte dans une phase continue, l'ensemble étant soumis à la gravité. Ce système fait apparaître des écoulements récemment décrits pour une goutte d'eau dans l'huile de paraffine. Ce système constitue également un modèle simple pour l'étude des propriétés aux interfaces, Mais d'un point de vue numérique, se pose alors le problème de la stabilité des algorithmes pouvant être utilisés. Les effets aux interfaces impliquent en effet des domaines spatiaux très limités dans lesquels les grandeurs physiques entre les deux fluides sont discontinues. D'importants artéfacts numériques peuvent alors être générés dans les simulations et faire perdre la richesse de la physico-chimie du système considéré. Le problème de la simulation d'écoulements multiphasiques intéresse aussi bien le monde académique que le monde industriel. L'objectif de ce travail de thèse est donc d'implémenter les techniques numériques les plus récentes et de développer un code pour permettre la simulation de l'hydrodynamique de systèmes dispersés. Pour parvenir à ce but, il reste encore des problèmes algorithmiques importants à résoudre comme la prise en compte des effets thermocapillaires et thermosolutaux. Ces deux derniers points sont l'objet de cette thèse
For several decades, an important scientific activity has focused on the numerical, theoretical and experimental hydrodynamics of drops. This work presents numerical results of a single droplet in the gravity field and in non-isothermal conditions. The simulation such a multiphase system is important in both academic and industrial world. This is particularly the case in the field of emulsions, wetting problems and evaporation. To achieve this goal, there are still important algorithmic problems due to the free moving interfaces and the description of capillary effects. Here, a Volume of Fluid technique has been implemented with high order temporal and spatial schemes to preserve the sharpness of the drop interface. The system under consideration is a simplified model consisting in a single water droplet in a continuous paraffin oil phase. These liquids are immiscible and non-compressible and the overall evolution is unsteady. Capillary contributions such as temperature and surfactant dependent surface tension are fully accounted for. This presentation is aimed to show the capabilities of VOF techniques for the simulations of unsteady multiphase systems in non-isothermal configurations. The role of the droplet initial position and temperature field is described with good numerical stability. There are still important problems remaining in the simulation of free interface systems with such a technique. Spurious currents induced by the description of capillarity can in particular come into play. But these latter can be controlled once the droplet average velocity due to drainage becomes large enough

The aim of this thesis work was to gain understanding of the interactions between talc mineral and surfaces, liquids and chemicals relevant for industrial applications, such as pulp and paper. Talc is used in the pulp and paper industry as a filler pigment, in control of pitch (lipophilic extractives) deposits and as a coating pigment. A deeper understanding of talc interactions will be beneficial in optimizing its use. Long-range attractive interactions between talc and hydrophobic model probes, as well as pitch probes, have been measured using the atomic force microscope (AFM) colloidal probe method. Two procedures for preparation of pitch colloidal probes were developed to allow these studies. Model hydrophobic, nanorough surfaces with surface energy characteristics similar to talc have also been prepared and their interactions with hydrophobic model probes compared to interactions between hydrophobic model probes and talc. It is demonstrated that talc mineral interacts with model hydrophobic particles, as well as with pitch, by long-range attractive forces, considerably stronger than the expected van der Waals force. The possible origin of the measured interaction forces is discussed, and the conclusion is that the main cause is an attractive capillary force due to formation of a gas/vapor capillary between the surfaces. Force measurements using model hydrophobic, nanorough surfaces show that a large-scale waviness does not significantly influence the range and magnitude of the capillary attraction, but large local variations in these quantities are found. It is demonstrated that a large variation in adhesion force corresponds to a small variation in local contact angle of the capillaries at the surfaces. The nature of the surface topographical features influences the capillary attraction by affecting the local contact angle and by pinning of the three-phase contact line. The effect is clearly dependent on the size of the surface features and whether they exist in the form of crevices or as extending ridges. Entrapment of air also affects the imbibition of water in pressed talc tablets. The effects of wetting and dispersion agents on the interactions between talc and hydrophobic probes have also been investigated. It is demonstrated that a common dispersing agent used for talc, poly(acrylic acid), does not affect the capillary attraction between talc and non-polar probes. In fact, the results strongly suggest that poly(acrylic acid) does not adsorb on the basal plane of talc. From this finding it is inferred that the stabilizing effect of this additive most likely is due to adsorption to the edges of talc. In contrast, a wetting agent (the non-ionic triblock copolymer Pluronic PE6400) removes the long-range capillary attraction. It is suggested that such an ability to replace air at the talc surface is of great importance for an efficient wetting agent. The Hamaker constant for talc has also been estimated by using optical data obtained from spectroscopic ellipsometry. It is demonstrated that a nanocrystalline talc mineral, cut in different directions displays very small differences in Hamaker constant between the different crystallographic orientations, whereas a microcrystalline sample displays a significantly higher value. The estimated Hamaker constants are discussed for different material combinations of relevance for the pulp- and paper industry, such as cellulose and calcium carbonate.
Målet med detta avhandlingsarbete var att öka förståelsen för interaktioner mellan talkmineral och ytor, vätskor och kemikalier relevanta för industriella applikationer, såsom papper och massa. Talk används i pappers- och massaindustrin som fyllmedel, för kontroll av hartsrika (lipofila extraktivämnen) avsättningar och som bestrykningspigment. En djupare förståelse för talkinteraktioner kommer att vara användbart för att optimera dess användning. Långväga attraktiva interaktioner mellan talk och hydrofoba modellpartiklar, såväl som mellan talk och hartspartiklar, har uppmätts med hjälp av atomkraftsmikroskopi (AFM) genom att fästa kolloidala partiklar på kraftsensorn. Två metoder för att framställa partiklar gjorda av harts har utvecklats för att möjliggöra dessa studier. Hydrofoba, nanostrukturerade modellytor med ytenergier liknande de för talk har också tillverkats och deras växelverkan med hydrofoba modellpartiklar har jämförts med dem mellan talk och hydrofoba modellpartiklar. Studierna visar att talkmineral växelverkar med hydrofoba modellpartiklar, såväl som med harts, genom långväga attraktiva krafter som är betydligt starkare än den förväntade van der Waals kraften. Möjliga orsaker till de uppmätta växelverkanskrafterna diskuteras och slutsatsen blir att huvudorsaken är en attraktiv kapillärkraft som uppkommer genom att en gas-/ångkapillär bildas mellan ytorna. Kraftmätningar gjorda med hydrofoba nanostrukturerade modellytor visar att en storskalig vågighet inte nämnvärt påverkar storleken av kapillärattraktionen, men stora lokala variationer existerar. Det demonstreras att en stor variation i adhesionskraft motsvaras av en liten variation i lokal kontaktvinkel för kapillärerna på ytorna. Ytornas topografi påverkar kapillärattraktionen genom att påverka den lokala kontaktvinkeln samt genom att trefaskontaktlinjen inte kan röra sig fritt över ytan. Effekten är tydligt beroende av huruvida ytojämnheterna existerar i form av nedsänkningar eller upphöjningar. Instängd luft påverkar också pressade talktabletters uppsugningsförmåga av vatten. Vätnings- och dispergeringsmedels inverkan på växelverkan mellan talk och hydrofoba partiklar har undersökts. Resultaten visar att ett vanligt dispergeringsmedel för talk, polyakrylsyra, inte påverkar kapillärattraktionen. I själva verket tyder data på att polyakrylsyra inte adsorberas på talks basalplan. Utifrån dessa resultat dras slutsatsen att polyakrylsyra stabiliserar talkdispersioner genom att adsorbera på talkkanterna. Ett vanligt vätmedel (nonjonisk triblock sampolymer Pluronic PE6400) tar å andra sidan bort långväga kapillärattraktion. Detta antyder att egenskapen att ersätta luft på talkytan är av stor betydelse för effektiva vätmedel. Hamakerkonstanten för talk har uppskattats genom att utnyttja optiska data från ellipsometrimätningar. Det demonstreras att ett nanokristallint talkmineral kapat i olika riktningar uppvisar mycket små skillnader i Hamakerkonstant mellan de olika kristallografiska orienteringarna, medan ett mikrokristallint prov uppvisar ett betydligt högre värde. De beräknade Hamakerkonstanterna diskuteras för olika materialkombinationer relevanta för pappersindustrin, såsom cellulosa och kalciumkarbonat.
QC 20100813

Thesis (Ph. D.)--Florida State University, 2003.
Advisor: Dr. John G. Dorsey, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Sept. 08, 2004). Includes bibliographical references.

碩士
國立臺灣大學
化學研究所
97
Carbon nanotubes (CNTs) belong to the fullerene family of carbon allotropes. The walls of the tubes consist of hexagonal carbon, and the end caps contain pentagonal rings. Their specific physical properties, such as high surface areas and mechanical and electrical properties, make CNTs interesting to analytical science. In our work, a special type of MEKC, NaDDBs-coated MWCNTs EKC was used for the separation of biomolecules. Sodium dodecylbenzenesulfonate (NaDDBs) was used for the dispersion of carbon nanotubes. NaDDBs is composed of two parts: the long hydrophobic chain and the benzylsulfonate group. In comparison with the conventional surfactant used in MEKC, sodium dodecylsulfate (SDS), NaDDBs suspends more MWCNTs (about 100-fold) than SDS, and the π-π interaction between the benzene ring of NaDDBs and MWCNTs prolongs the slurry suspension time. Using NaDDBs as surfactant can reduce the required amount of MWCNTs and decrease the baseline noise. Even the system without micelle could make the good pseudostationary phase. To produce a stable suspension, various ratios (w/w) of MWCNTs to NaDDBs over the range from 1:10 to 1:20 were studied with turbidimetry. The ratio of 1:10 produces the most stable form. Considering this, several parameters affecting the CE separation were studied, including the amount of surfactant and of MWCNTs, the buffer pH, composition and concentration, as well as the organic modifier. The results show that 8 mg L-1 of NaDDBs-coated MWCNTs (0.8 mg/L) as the pseudostationary phase in a phosphate buffer (30 mM, pH 8) as the mobile phase could provide the best recognition for 7 nucleoside monophosphates, baseline separating even the geometric isomers. In the stacking mode, adding 10% MeOH to the sample mixture in a phosphate buffer (50 mM, pH 9) containing 0.8 mg L-1 MWCNTs and 8 mg L-1 NaDDBs, 12 model compounds, including nucleoside mono-, di- and tri-phosphates, were resolved. The nucleotides with a more electron-withdrawing functional group have a strong interaction with MWCNTs because of the π electron donor and π electron acceptor interaction. From the retention behavior of each analyte, the separation mechanism was suggested to be hydrogen bonding and a hydrophilic interaction between surfactant and analytes, as well as hydrophobic force and π-π interaction between MWCNTs and nucleotides, in addition to the electrophoretic mobility difference.

碩士
國立高雄師範大學
化學系
100
Sertraline (SER) is a widely used antidepressant belonging to the selective serotonin reuptake inhibitors (SSRIs). SER is commonly used to treat depression, obsessive compulsive and panic disorders. In the study, we developed a simple and rapid dispersive liquid-liquid microextraction (DLLME) coupled with capillary electrophoresis for analyzing SER in urine sample. In this method, a mixture of extraction solvent and disperser solvent is rapidly injected into a 1.00mL urine sample. SER in the urine sample are extracted into the fine droplets of extraction solvent. Under optimum conditions, the linear range and limits of detection were 0.05-1.0 μM and 5.1 nM, respectively. The extraction time was less than 1 min. Compared with the conventional sample preparation method, the proposed method has the advantage of rapidity and ease of operation, and low consumption of organic solvent.

碩士
靜宜大學
化粧品科學系
104
This study is to propose a novel method for determination regulations limits used sebum softener, such as Mandelic Acid,Salicylic acid and Resorcinol on detection in cosmetics. For this purpose, a fastly and convenient analytical instrument Capillary Electrophorsis (CE) combine with Dispersive liquid-liquid micro extraction (DLLME) was designed, and this parameters were studied by orthogonal experimental design and statistical analysis to optimize. The Taguchi Method was applied to at L16(215) and L18 (21×37) orthogonal experimental design. According to the number of chromatographic peaks, peak signal strength and retention time, separation voltage at -25 kV and a background electrolyte(BGE, 10 mM phosphate buffer at pH 9) were used. Sebum softeners in cosmetics were analyzed by CE at 220 nm. For measured in quantifying the collected solvent, the present work utilizes a self-designed glass tube in the extraction process. The optimum parameters for MA, SA and Res were investigated. Parameters influencing the extraction efficiency of DLLME-BE-CE, such as the extraction and dispersive solvent, solvent volume, and salt-addition were thoroughly investigated and optimized. After that, the maximum extraction efficiency was obtained by loading 20 µL 10mM HCl 3 mL sample solution, by the addition of 200 μL Octanol (extractant) and 80 μL Acetonitrile. Then the device was sealed with parafilm, and the cloudy solution was centrifuged at 3000 rpm for 3min and the separated extractant was injected directly into CE for analysis. By the ANOVA(analysis of variance),we can find the parameters which influence the extraction solvent type and the optimum combination of parameter values. Under the selected conditions,determination of sebum softeners ranged in 10-2000 ng/mL. The coefficient of determination were obtained above 0.9935. Detection limits were achieved at the level of 0.5-6.7 ng/mL. Quantitative limits were achieved at the level of 2.7-18.4 ng/mL. The relative standard deviations of intra-day and inter-day precisions were 4.58-8.44 % and 7.35-15.68 %. The extraction time was less than 10 minutes. The results demonstrated that the proposed DLLME-BE-CE method provides a simple, rapid, inexpensive, convenient, eco-friendly and less matrix interferences process for the determination sebum softener in cosmetic samples.

碩士
國立高雄師範大學
化學系
105
A method for the determination of carbamazepine (CBZ) and clobazam (CLB) using cyclodextrin-assisted dispersive liquid-liquid microextraction (CA-DLLME) combined with sweeping capillary electrophoresis (CE) was developed. A 1 mL aliquot of sample containing 4×10-4 M α-cyclodextrin (α-CD) was placed into a vail. Then, 100 µL chloroform was rapidly injected into the aqueous sample to form a cloudy solution. After extraction, CBZ and CLB were detected through capillary electrophoresis combined with sweeping. Under optimal extraction and stacking conditions, the limits of detection (LOD) at a signal-to-noise of 3 were 0.5 and 0.6 ng/mL for CBZ and CLB, respectively. The sensitivity enhancement for CBZ and CLB were calculated to be 3757 and 4675, respectively. This developed method was successfully applied to the determination of CBZ and CLB in human urine samples. Linear ranges of 2-40 µg/mL were obtained for CBZ and CLB in urine samples. The LODs for urine samples were 0.5 and 0.6 ng/mL, respectively. Recoveries of CBZ and CLB in urine samples were 74.6 % and 73.2 %, respectively. This method provides simplicity and rapidity for the determination of CBZ and CLB in human urine samples.

碩士
國立高雄師範大學
化學系
106
A method for the analysis of Carbendazim using surfactant-assisted dispersive liquid-liquid microextraction (SA-DLLME) combined with field-amplified sample stacking (FASS) in capillary electrophoresis (CE) was developed. 90 μL dichloromethane was used as the extraction solvent and rapidly injected into a 1.0 mL aqueous sample (containing 2 × 10-4 M Triton X-100) to form a cloudy solution. After the extraction, Carbendazim was analyzed using CE combined with FASS. Under optimal extraction and stacking conditions, the limits of detection (LOD) of carbendazim were 24.7 nM. The sensitivity enhancement for carbendazim were calculated to be 1015. This method provides simplicity, rapidity, and high extraction efficiencies for detection of carbendazim.

碩士
國立高雄師範大學
化學系
103
Dispersive liquid-liquid microextraction followed by viscosity and field-amplifed sample stacking in capillary electrophoresis was determined to be a simple, fast and sensitive analytical method for simultaneously detecting three phenothiazines (promazine, chlorpromazine, and triflupromazine) in a human urine sample. The separation buffer was composed of 40mM phosphate solution (pH 2.5) and 10% (v/v) glycerol. Because glycerol exhibits viscosity, the resolution of the samples and the effect of the stacking could be substantially improved. Under optimized conditions, enrichment factors were obtained that ranged from 1190 to 2067. The proposed method for promazine, chlorpromazine and triflupromazine provided a good linearity that ranged from 0.75 to 200 nM, with correlation coefficients (r) ranging from 0.9975 to 0.9984. The limits of detection based on a signal-to-noise ratio of 3 ranged from 0.15 to 0.22 nM. The relative standard deviations of the target analytes were below 5%. The recoveries of three phenothiazines for urine samples at spiking levels of 50 to 200 nM were 87.0%~106.8%. With the advantages of a short analysis time, high enrichment factors, and high precision and accuracy, the developed method was successfully applied to determine phenothiazine drugs in human urine samples.

碩士
國立高雄師範大學
化學系
106
This study was divided into two parts . First, rapid enantioseparation of three basic drugs (RS-Carvedilol, RS-Terbutaline, and RS-Metaproterenol ) was performed , with dimethyl-β-cyclodextrin (DM-β-CD) as the chiral selector and poly(diallyldimethylammonium chloride) (PDDAC) in the background electrolyte as buffer additive. Under optimized conditions, the separation system－which comprised 5mM DM-β-CD and 0.9 % PDDAC at pH 2.5 , with a capillary length of 35 cm, enabled three pairs of RS-Carvedilol, RS-Terbutaline, and RS-Metaproterenol and internal standard (losartan potassium) to be successfully separated in 10 min. Second, dispersive liquid－liquid microextraction was used in capillary electrophoresis. Under optimum conditions,the use of 1.00 mL of sample solution, 30 μL of dichloromethane as the extraction solvent, and 200 μL of acetonitrile as the dispersive solvent and, yielded a high enrichment factor in the range of 121－124 at an extraction time of less than 3 min. Moreover, a strong linearity was obtained from 0.09－to 10 μM (r >0.9956). In real samples, the recoveries of RS-Carvedilol from urine and serum samples were in the ranges of 74 %－123 % and 70 %－127 % , respectively.

碩士
國立高雄大學
應用化學系碩士班
102
Pesticides are the pollutants and high persistence in the environment. Their residues present in fruits and vegetables may represent a serious hazard to human health. Analysis of pesticides is a difficult task for food safety since frequently they are found in low concentrations with complex matrices such as soils, foods, etc. Capillary electrophoresis (CE) is increasingly popular in environmental field due to its high separation efficiency, speed of analysis, low consumption of sample and reagent and simplicity, however, with inadequate limit of detections (LODs) . To overcome detection problems, one is to use more sensitive detection systems (i.e., mass spectrometry), the other one is to develop the preconcentration procedures based on on-line stacking methods or based on off-line operation procedures (solid-phase extraction, or solid-phase microextraction). The thesis is to separate nine pesticides by CE at the same time. The optimized buffer is [Borax 10 mM, SDS 60 mM, pH 9.2] with 18% (v /v) ACN. The separation time is within 13 minutes. After the combination both preconcentration procedures (LD-DLLME and Sweeping) allowed the determination of these pesticides in water samples at concentration between 0.28 to 2.3 ppb. Apparent recovery values were in the range 69.5-117%. The enhancement factors of LODs are 350 to 3407 times. The potential of the method was the first time of using Low density dispersive liquid-liquid microextraction (LD-DLLME) combined with Sweeping to determine the pesticides in the water samples.

碩士
國立高雄師範大學
化學系
104
A method for the determination of Lidocaine (Lid) and Mexiletine (Mex) using surfactan-assisted dispersive liquid-liquid microextraction (SA-DLLME) combined with field-amplified sample stacking (FASS) in capillary electrophoresis (CE) was developed. A 1 mL aliquot of sample containing 2×10-4 M Triton X-100 and 6% NaCl was placed in a vail. Then, 110 μL methylene chloride was rapidly injected into the aqueou sample to form a cloudy solution. After extraction, Lid and Mex was detected through CE/UV combined with FASS. Under optimal extraction and stacking conditions, the LODs of Lid and Mex were 6 and 9 nM, respectively. The sensitivity enhancement for Lid and Mex were calculated to be 1250 and 1141, respectively. This developed method was successfully applied to the determination of Lid and Mex in human urine and serum samples. The LODs of Lid and Mex in urine and serum samples were 8 - 13 nM and 30 - 100 nM, respectively. Recoveries of Lid and Mex in urine and serum samples were 54.7 - 64.9% and 16.1 - 56.5%, respectively. This method provides simplicity, rapidity, and high extraction efficiencies for the determination of Lid and Mex in human urine and serum samples.

碩士
國立高雄師範大學
化學系
106
Dispersive liquid–liquid microextraction followed by viscosity and polymer stacking in capillary electrophoresis was determined to be a simple and sensitive analytical method for detecting RS-Warfarin and its metabolite RS-7-OH-Warfarin in human urine and serum. The separation buffer comprised 200 mM Tris-borate (pH 8.5) and 0.5% (w/v) poly(ethylene oxide) (PEO). Because PEO exhibits viscosity and an intermolecular force interaction between PEO and analytes, the effect of the polymer tacking and detection sensitivity could be substantially improved. The enrichment factors obtained under optimized conditions ranged from 1758 to 1859. The proposed method for detecting RS-Warfarin and RS-7-OH-Warfarin provided a strong linearity that ranged from 1.5 to 600.0 nM, with correlation coefficients (r) ranging from 0.9952 to 0.9962. The detection limits based on a signal-to-noise ratio of 3 ranged from 0.33 to 0.38 nM. The relative standard deviations of the target analytes were all below 5% (n = 12). In the real sample, the recoveries of analytes for the urine sample at spiking levels of 50–200 nM and the serum sample at spiking levels of 0.05–2 μM were in the ranges of 91.9%–106.2% and 96.5%–103.5%, respectively. With the advantages of high enrichment factors and high accuracy and precision, the developed method was successfully applied to determine drugs in urine and serum.

Evaluating data in capillary zone electrophoresis usually involves many steps that require using several different programmes. Apart from evaluating the electrophoreogram itself, it is usual to process the obtained data in some other way. For example, a suitable model is fit to the data in order to obtain physical and chemical parameters of the separation (e.g. stability constant in case of complexation). It is also important to know the accuracy of the evaluation (the calculation error). In this work, new parts of the Eval programme, originally developed for electrophoreogram evaluation, were implemented. The programme now automatically estimates the Haarhoff-van der Linde function (solution of continuity equation in capillary) parameters for analyte peak. Complexing agents are often used to improve the separation in the capillary zone electrophoresis. Complexation in the capillary can be described by its physical and chemical parameters. A new part was added to the Eval programme that allows the user to fit a rectangular hyperbole function to the obtained data. Thus, the regression parameters of this dependence can be gained. The programme can also draw profile diagrams for these parameters, from which the confidence intervals can be read. An option that allows two dependencies to be fitted at...

碩士
國立高雄師範大學
化學系
107
Surfactant-assisted dispersive liquid-liquid microextraction combined with on-line concentration - polymer stacking ( SA-DLLME-Polymer stacking ) in capillary electrophoresis was determined to be a simple and sensitive analytical method for detecting R,S-Mirtazapine and its metabolite R,S-Desmethyl mirtazapine, R,S-8-Hydroxy mirtazapine in human urine and serum. The electrophoretic analyses were carried out in 10 mM Phosphate buffer solution at pH 3.0 containing 0.9 % [Poly (diallyldimethylammonium chloride)] ( PDDAC ) and 20 mM Dimethyl-β-cyclodextrin.Because PDDAC exhibits viscosity, the effect of the polymer stacking and detection sensitivity could to substantially improved. The enrichment factors obtained under optimized conditions ranged from 2725 to 3879. The proposed method for detecting R,S-Mirtazapine and its metabolite provided strong linearity that ranged from 1.5 to 1500.0 nM, the limits of detection (LODs) ranged from 0.3 to 0.5 nM. In the real sample, the recovery of analytes for the urine sample at spiking levels of 1.5-150.0 nM and the serum sample at spiking levels of 5.0 – 250.0 nM were in the ranges of 89.0 – 116.5 % and 88.5 – 112.8 %, respectively. With the advantages of high enrichment factors and high accuracy and precision, the developed method was successfully applied to determine drugs in urine and serum.

Capillary electrophoresis often uses complexing agents since the interaction between the analyte and the complexing agent can result in achieving or improving the separation. Examples of such methods can be electrokinetic chromatography or affinity capillary electrophoresis (ACE). ACE is used to determine the complexing parameters. In case of chiral separation, this issue gets complicated, since the parameters of the two analytes (enantiomers) are not completely independent to one another. Therefore, a procedure has been proposed in this thesis, that should always be used to evaluate the complexing parameters of two enantiomers. Statistical evaluation of these parameters was assessed as well. This work also proposes a method that allows to determine the relative migration order of two enantiomers in two different complexing separation systems. The mathematical description of electrophoresis is based on continuity equations, that are inherently nonlinear. However, these equations can be linearized to obtain an approximate analytical solution. There was recently presented a generalized model, that enables inclusion of complete complexing equilibria in the theoretical description of electromigration. Thus, various phenomena, including nonlinear ones, associated with complexation can be predicted. This...

碩士
輔仁大學
化學系
106
Magnetic solid phase extraction (MSPE) is one of the most interesting sample preparation techniques developed in recent years. And the prepared polydopamine based magnetic@PDA was used as the sorbents for the MSPE. The magnetic@PDA were characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), Superconducting Quantum Interference Device Magnetometer (SQUID) and thermogravimetric analysis (TGA) in detail. In this study, a new, rapid, and efficient MSPE by LC-MS/MS were established for the extraction and sensitive detection of eleven phenolic acids compounds. Therefore, several major factors, namely, magnetic adsorbent, extraction solvent and desorption solvent, adsorbent amount, desorption solvent volume, extraction time and desorption time, were investigated by using a standard solution. Under the optimized conditions, analytes could be easily extracted by the proposed MSPE method. Results showed that the limits of detection (S/N = 3) for phenolic acid compounds were in the ranges of 0.01–0.29 ng/mL. The correlation coefficients of all analytes were more than 0.9985 and recoveries of six analytes were more than 80 %. The method was satisfactorily used for the detection of eleven analytes, and the recoveries of these targets for the spiked two wine (white grape wine and litchi wine) ranged from 80.03 to 133.04 % and from 84.00 to 116.1 %, respectively. In comparison to reported methods, the developed MSPE-HPLC-MS/MS showed some merits including low consumption of organic solvents, simplicity, satisfactory sensitivity and quickly.