Dissertations / Theses on the topic 'Column injection'

O uso de pesticidas levou ao aumento da produtividade e qualidade dos produtos agrícolas, porém o seu uso acarreta na intoxicação dos seres vivos pela ingestão gradativa de seus resíduos que contaminam o solo, a água e os alimentos. Dessa forma, há a necessidade do monitoramento constante de suas concentrações nos compartimentos ambientais. Para isto, busca-se o desenvolvimento de métodos de extração e enriquecimento de forma rápida, com baixo custo, gerando um baixo volume de resíduos, contribuindo com a química verde. Dentre estes métodos destacam-se a extração por banho de ultrassom e a extração por ponto nuvem. Após o procedimento de extração, o extrato obtido pode ser analisado por técnicas de Cromatografia a Líquido de Alta Eficiência (HPLC) e a Cromatografia por Injeção Sequencial (SIC), empregando fases estacionárias modernas, tais como as monolíticas e as partículas superficialmente porosas. O emprego de SIC com coluna monolítica (C18, 50 x 4,6 mm) e empacotada com partículas superficialmente porosas (C18, 30 x 4,6 mm, tamanho de partícula 2,7 µm) foi estudado para separação de simazina (SIM) e atrazina (ATR), e seus metabólitos, desetilatrazina (DEA), desisopropilatrazina (DIA) e hidroxiatrazina (HAT). A separação foi obtida por eluição passo-a-passo, com fases móveis compostas de acetonitrila (ACN) e tampão Acetato de Amônio/Ácido acético (NH4Ac/HAc) 2,5 mM pH 4,2. A separação na coluna monolítica foi realizada com duas fases móveis: MP1= 15:85 (v v-1) ACN:NH4Ac/HAc e MP2= 35:65 (v v-1) ACN:NH4Ac/HAc a uma vazão de 35 µL s-1. A separação na coluna com partículas superficialmente porosas foi efetivada com as fases móveis MP1= 13:87 (v v-1) ACN: NH4Ac/HAc e MP2= 35:65 (v v-1) ACN:NH4Ac/HAc à vazão de 8 µL s-1. A extração por banho de ultrassom em solo fortificado com os herbicidas (100 e 1000 µg kg-1) resultou em recuperações entre 42 e 160%. A separação de DEA, DIA, HAT, SIM e ATR empregando HPLC foi obtida por um gradiente linear de 13 a 35% para a coluna monolítica e de 10 a 35% ACN na coluna com partículas superficialmente porosas, sendo a fase aquosa constituída por tampão NH4Ac/HAc 2,5 mM pH 4,2. Em ambas as colunas a vazão foi de 1,5 mL min-1 e o tempo de análise 15 min. A extração por banho de ultrassom das amostras de solo com presença de ATR, fortificadas com concentrações de 250 a 1000 µg kg-1, proporcionou recuperações entre 40 e 86%. A presença de ATR foi confirmada por espectrometria de massas. Foram realizados estudos de fortificação com ATR e SIM em amostras de água empregando a extração por ponto nuvem com o surfactante Triton-X114. A separação empregando HPLC foi obtida por um gradiente linear de 13 a 90% de ACN para a coluna monolítica e de 10 a 90% de ACN para a coluna empacotada, sempre em tampão NH4Ac/HAc 2,5 mM pH 4,2. Em ambas as colunas a vazão foi de 1,5 mL min-1 e o tempo de análise 16 min. Fortificações entre 1 e 50 µg L-1 resultaram em recuperações entre 65 e 132%.<br>The use of pesticides has led to increased productivity and quality of agricultural products, but its use brings the intoxication of living beings by the gradual intake of their residues that contaminate soil, water and food. Thus, there is the need for constant monitoring of their concentrations in environmental compartments. For this, there is a quest for development of fast extraction and enrichment methods, at low cost, generating a low volume of waste, contributing to green chemistry. These methods include the extraction assisted by ultrasound bath and the cloud point extraction. After the extraction, the extract obtained can be analyzed by techniques such as High Performance Liquid Chromatography (HPLC) and Sequential Injection Chromatography (SIC) employing modern stationary phases, such as monolithic and superficially porous particles. The use of SIC with either monolithic column (C18, 50 x 4.6 mm) or column packed with superficially porous particles (C18, 30 x 4.6 mm, 2.7 µM particle size) was studied for separating simazine (SIM) and atrazine (ATR), and metabolites, deethylatrazine (DEA), deisopropylatrazine (DIA) and hydroxyatrazine (HAT). Separation was obtained by stepwise elution, with a mobile phase consisting of acetonitrile (ACN) and 2.5 mM ammonium acetate / acetic acid (NH4Ac / HAc) pH 4.2 buffer. The separation was performed with two mobile phases: MP1 = 15:85 (v v -1) ACN: NH4Ac / HAc and MP2 = 35:65 (v v-1) ACN: NH4Ac / HAc at a flow rate of 35 µL s-1. The separation in the column with superficially porous particles was carried out with the mobile phases MP1 = 13:87 (v v-1) ACN: NH4Ac / HAc and MP2 = 35:65 (v v-1) ACN: NH4Ac / HAc at 8 µL s-1. The ultrasound bath extraction from a soil fortified with herbicides (100 and 1000 µg kg-1) resulted in recoveries between 42 and 160 %. Separation of DEA, DIA, HAT SIM and ATR was obtained by HPLC employing a linear gradient from 13 to 35% for the monolithic column and from 10 to 35% ACN in the column packed with superficially porous particles, with the aqueous phases consisting of 2.5 mM NH4Ac / HAc buffer pH 4.2. In both columns the flow rate was 1.5 mL min-1 and the analysis time was15 min. Ultrasonic extraction from a soil sample containing ATR, fortified with concentrations from 250 to 1000 µg kg-1, provided recoveries between 40 and 86%. The presence of ATR was confirmed by mass spectrometry. Fortification studies with ATR and SIM were carried out in water samples employing cloud point extraction using Triton-X114 surfactant. The separation was accomplished by HPLC using a linear gradient from 13 to 90 % of ACN for the monolithic column and from 10 to 90 % ACN for the packed column, always in 2.5 mM NH4Ac / HAc pH 4.2 buffer. In both columns the flow rate was 1.5 mL min -1 and the analysis time 16 min. Fortifications between 1 and 50 µg L-1 resulted in recoveries between 65 and 132%.

Dans les puits de production d’eau, de pétrole, de gaz et de chaleur géothermique, ou dans les puits d’accès à un stockage d’hydrocarbures, il est précieux de connaître la perméabilité de la formation ou de sa couverture en fonction de la profondeur, soit pour améliorer le modèle de réservoir, soit pour choisir les zones dans lesquelles procéder à des opérations spéciales.On propose une technique qui consiste à balayer la hauteur du découvert par une interface entre deux liquides de viscosités très contrastées. Le débit total qui pénètre la formation à chaque instant est ainsi une fonction de la position de l’interface et de l’historique des pressions dans le puits. On doit alors résoudre un problème inverse : rechercher la perméabilité fonction de la profondeur à partir de l’historique des débits dans le temps. Dans la pratique, le puits est équipé d’un tube central. Le balayage est effectué par injection d’un liquide à pression d’entrée constante dans le tube central et soutirage d’un autre liquide par l’espace annulaire. On mesure les débits d’injection et de soutirage dont la différence est le débit qui entre dans la formation.Pour valider et améliorer cette technique, on a d’abord utilisé une maquette simulant un découvert multi-couches disponible au LMS. On a exploité aussi des essais en place réalisés dans la couverture peu perméable d’un stockage souterrain de gaz. Dans ces essais, un liquide visqueux placé dans le découvert était déplacé par un liquide moins visqueux (méthode dite « opening »). Les couches plus perméables étaient correctement identifiées (Manivannan et al. 2017), mais une estimation quantitative était un défi en raison des phénomènes transitoires qui affectent le voisinage immédiat des puits. De plus, le rayon investigué dans le massif était petit.La thèse a relevé ces défis en proposant un essai légèrement différent et une nouvelle technique d’interprétation. Les essais avec une maquette modifiée ont montré la supériorité d’une méthode « closing » dans laquelle le puits est d’abord rempli du liquide le moins visqueux. On ménage une période de stabilisation avant l’injection du liquide visqueux pour réduire les effets transitoires ; elle permet aussi d’estimer la perméabilité moyenne et l’influence de la zone endommagée à la paroi (le « skin »).Puis on conduit l’essai proprement dit. L’historique des débits mesurés en tête de puits constitue le profil d’injection dont on déduit le profil de perméabilité.. Cette estimation suppose un écoulement monophasique dans chaque couche et la même « skin » pour toute la formation. Les incertitudes principales portent sur les pressions de formation et les variations possibles du « skin ». Elles sont estimées au moyen d’un calcul analytique. On a vérifié sur la maquette que les profils de perméabilité estimés présentent une bonne concordance avec les perméabilités mesurées avant les essais.On a réalisé un essai sur un sondage de 1750 m de long atteignant une couche de sel dont on a correctement estimé la perméabilité moyenne pendant la période de stabilisation. Toutefois elle était si faible (4.0E-21 m²) que l’utilisation de deux fluides n’a pas permis de faire une différence entre les diverses parties du puits<br>In wells producing water, oil, gas or geothermal energy, or in access wells to hydrocarbon storage, it is critical to evaluate the permeability of the formation as a function of depth, to improve the reservoir model, and also to identify the zones where additional investigation or special completions are especially useful.A new technique is proposed, consisting of scanning the open hole (uncased section of the wellbore) with an interface between two fluids with a large viscosity contrast. The injection rate into the formation depends on interface location and well pressure history. An inverse problem should be solved: estimate permeability as a function of depth from the evolution of flow rates with time. The wells are usually equipped with a central tube. The scanning is done by injecting a liquid in the central tube at constant wellhead pressure. Injection and withdrawal rates are measured at the wellhead; the difference between these two rates is the formation injection rate.To validate and improve this technique, we used a laboratory model mimicking a multi-layer formation, already available at LMS. We also made use of in-situ tests performed on an ultra-low permeable cap rock above an underground gas storage reservoir. In these tests, a viscous fluid contained in the open hole was displaced by a less-viscous fluid (a method called opening WTLog). The more permeable layers were correctly identified (Manivannan et al. 2017), but a quantitative estimation was challenging due to transient phenomena in the vicinity of the wellbore (near-wellbore zone). In addition, the investigation radius was small.These challenges are addressed by proposing a slightly modified test procedure and a new interpretation workflow. Laboratory tests with a modified test setup showed the advantages of the ‘closing’ method in which the well is filled with a less-viscous fluid at the start of the test. We also added a stabilization period before the injection of viscous fluid to minimize the transient effects; this period is also used to estimate the average permeability of the open hole and the effect of near-wellbore damage (skin).Then the test proper is performed (closing WTLog). The injection profile of the less-viscous fluid is computed from the wellhead flow rate history. A permeability profile is estimated from the injection profile. The permeability estimation considers a monophasic flow in each layer and the same skin value for all the formation layers. Major uncertainties in the permeability estimates are caused by formation pressures and heterogeneities in skin values; they are estimated using an analytical formula. We have verified on the laboratory setup that the estimated permeability profiles are well correlated to the permeabilities measured before the tests.An attempt was made to perform a WTLog in a 1750-m long wellbore opening in a salt formation. The first phase was successful and the average permeability was correctly assessed. However, this permeability was so small (4.0E-21 m² or 4 nD) that the gauges and the flowmeters were not accurate enough to allow a clear distinction between the permeabilities of the various parts of the open hole

Made available in DSpace on 2014-10-09T12:37:34Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:03:32Z (GMT). No. of bitstreams: 1 05177.pdf: 1071515 bytes, checksum: 549d323670762fe6597fcda6cf7ea4fc (MD5)<br>Tese (Doutoramento)<br>IPEN/T<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

The PhD research activities are focused on ground improvement application. The objective is to study the permeation grouting technique in granular soils and to understand the hydro-mechanical properties that can be obtained using non-conventional injection materials. During the project it has been developed an injection apparatus and a monitoring system of the grouting process that is used to study the permeation process and to develop a theoretical, and then analytical and numerical approach. Furthermore, the injection apparatus is used to simulate the permeation of different injection materials in soils and to generate specimen for hydraulic and mechanical evaluations. The experimental set-up comprises of a polycarbonate extruded clear tube, 50 mm in inner diameter and variable length (with a maximum of 1.6 m), and two floating caps at the extremities with a double sealing system. Once it has been filled with a selected soil it is inserted in a rigid steel chassis and the hole injection system can support 100 bar injection pressure. To simulate the soil micro-mechanical behavior has been created a loading system, composed by a screw that can apply a confining pressure on the soil sample. The column is then instrumented: • two load cells to control the confining pressure; • five pressure transducers to control the imposed pressure; • two pressure switches to impose pressure to the fluid; • laser ranging distance sensors to measure the flow rate; • vision camera to detect fluid front advancement. The data from the sensors are collected by employing Arduino processors and all the results are elaborated and displayed in real time with a Labview platform software. Some of the sensors were properly calibrated after being installed and all the measurements and the injection apparatus are validated before starting the test. The injection apparatus has been used to test different conventional and non-conventional grout with different rheological properties: sodium silicate, acrylic resin, colloidal silica, cement and micro-cement grout. For some of the previous injection materials have been defined a rheological time-dependent law. All these tests have been used to understand the permeation phenomena and to define an analytical and numerical predictive model that could be valid for all the soil in all conditions. By using this approach and by knowing the soil hydraulic properties, related to a new geotechnical project, it should be possible to indicate to designers the type of grout, the injection parameters and the injection geometry for this specific ground improvement application. Finally, a hydro-mechanical investigation of the different injection materials has been performed, consisting of the following test: permeability, unconfined compressive strength, triaxial test and brasilian test. For each injection test it has been evaluated the difference mechanical behavior from the bottom to the top part of the column, resulting from a variable soil saturation during the permeation process, that, in a ground with a grout spherical propagation, can be related to the radial distance from the injection point. Furthermore, a mechanical comparison, in term of friction angle and cohesion, is performed for the different grout types and, for some of them, at different curing time.<br>The PhD research activities are focused on ground improvement application. The objective is to study the permeation grouting technique in granular soils and to understand the hydro-mechanical properties that can be obtained using non-conventional injection materials. During the project it has been developed an injection apparatus and a monitoring system of the grouting process that is used to study the permeation process and to develop a theoretical, and then analytical and numerical approach. Furthermore, the injection apparatus is used to simulate the permeation of different injection materials in soils and to generate specimen for hydraulic and mechanical evaluations. The experimental set-up comprises of a polycarbonate extruded clear tube, 50 mm in inner diameter and variable length (with a maximum of 1.6 m), and two floating caps at the extremities with a double sealing system. Once it has been filled with a selected soil it is inserted in a rigid steel chassis and the hole injection system can support 100 bar injection pressure. To simulate the soil micro-mechanical behavior has been created a loading system, composed by a screw that can apply a confining pressure on the soil sample. The column is then instrumented: • two load cells to control the confining pressure; • five pressure transducers to control the imposed pressure; • two pressure switches to impose pressure to the fluid; • laser ranging distance sensors to measure the flow rate; • vision camera to detect fluid front advancement. The data from the sensors are collected by employing Arduino processors and all the results are elaborated and displayed in real time with a Labview platform software. Some of the sensors were properly calibrated after being installed and all the measurements and the injection apparatus are validated before starting the test. The injection apparatus has been used to test different conventional and non-conventional grout with different rheological properties: sodium silicate, acrylic resin, colloidal silica, cement and micro-cement grout. For some of the previous injection materials have been defined a rheological time-dependent law. All these tests have been used to understand the permeation phenomena and to define an analytical and numerical predictive model that could be valid for all the soil in all conditions. By using this approach and by knowing the soil hydraulic properties, related to a new geotechnical project, it should be possible to indicate to designers the type of grout, the injection parameters and the injection geometry for this specific ground improvement application. Finally, a hydro-mechanical investigation of the different injection materials has been performed, consisting of the following test: permeability, unconfined compressive strength, triaxial test and brasilian test. For each injection test it has been evaluated the difference mechanical behavior from the bottom to the top part of the column, resulting from a variable soil saturation during the permeation process, that, in a ground with a grout spherical propagation, can be related to the radial distance from the injection point. Furthermore, a mechanical comparison, in term of friction angle and cohesion, is performed for the different grout types and, for some of them, at different curing time.

The aim of this thesis is first and foremost to improve the fundamental knowledge of nonlinear and preparative separation theory by focusing on some of the remaining “white spots” on the theoretical chromatographic map. Secondly, the acquired knowledge is used to develop, validate and execute new methods for phase characterization in liquid chromatography. The methodology used in this thesis is a combination of experiments, fundamental nonlinear theory and systematic computer simulations. A fundamental knowledge of the molecular interactions between the compounds to be separated and the separation media requires the determination of adsorption isotherms over a broad concentration range to give a complete picture of all interactions in the separation system - weak as well as strong. In addition, such adsorption data is essential for optimization in preparative chromatography. For the first time, it has been experimentally shown that the injected molecules are not present in the detected peak when a small excess of molecules are injected into a chromatographic system equilibrated with a constant stream of identical molecules. Several experimental procedures for this method were developed such as (i) the optimal injection strategy and (ii) different labeling methods for visualizing the injected molecules. Remarkable phenomena in the single-component case, such as invisible peak deformation and deformed (invisible) frontal chromatograms, are reported, investigated, and explained. This phenomenon has asides from its future practical implementation, also a large didactic value. The accuracy of the ECP method is experimentally improved, and used to characterize the separation of protolytic compounds at different pH on modern commercially available silica and hybrid silica column packing materials. That investigation enables us to answer why basic compounds give a much more compact preparative peak profile at pH 11 than they yields at lower pH.

Estudou-se o emprego da Cromatografia a Líquido por Injeção Seqüencial (SIC) explorando o uso de uma cela de longo caminho óptico com guia de onda (LCW) de 100 cm para a melhora dos limites de detecção (LOD) e quantificação (LOQ) na determinação de atrazina (ATR), propazina (PRO) e simazina (SIM). Para isto, utilizou-se uma fase móvel com composição de 44:56 (v v-1) metanol : tampão acetato de amônio 1,25 mM, pH 4,7, coluna monolítica e a detecção espectrofotométrica em 238 nm. Obtiveram-se valores de LOD e LOQ, respectivamente, de 1,76 e 5,86 &#181;g L-1 para ATR, 4,51 e 15 &#181;g L-1 para PRO e 2,25 e 7,5 &#181;g L-1 para SIM. Com o emprego da cela de longo caminho óptico os valores de LOD ficaram abaixo dos recomendados pela US-EPA, que permite para águas potáveis uma concentração de 3 &#181;g L-1 para ATR, 4 &#181;g L-1 para SIM e 10 &#181;g L-1 para PRO. Realizaram-se estudos de adsorção de SIM, PRO e ATR e seus metabólitos desisopropilatrazina (DIA), desetilatrazina (DEA) e 2-hidroxiatrazina (HAT) em solo, ácido húmico e solo modificado com ácido húmico. Para isso foi utilizado um sistema de monitoramento on-line composto por um filtro tangencial e uma bomba peristáltica para circulação da suspensão. Foram realizados estudos cinéticos em duas etapas e, em ambas, foi utilizado um mix dos compostos com concentração inicial de 1,0 mg L-1 e gradiente de eluição passo a passo para a separação dos compostos utilizando três fases móveis com composições de 15 ou 28, 40 e 50% (v v-1) metanol : tampão acetato de amônio 1,25 mM pH 4,7. Na primeira etapa o tempo de contato entre triazinas e adsorventes foi de 90 min. Na segunda etapa foi utilizado apenas o solo como adsorvente e o tempo de contato foi de 24 h. Para a primeira etapa do estudo só foi possível aplicar modelo cinético de pseudo-segunda ordem, o qual permitiu estimar os valores de massa adsorvida de triazina por massa de adsorvente, sendo que o ácido húmico é o material com maior capacidade adsortiva (1470 ± 43&#181;g g-1 para DIA a 2380 ± 51 &#181;g g-1 para PRO). O composto mais adsorvido em solo é PRO (26,5 ± 0,1 &#181;g g-1). A presença de ácido húmico no solo aumentou a adsorção de ATR (de 19,4 ± 0,7 para 23 ± 2 &#181;g g-1), de HAT (10,9 ± 0,7 para 18 ± 2 &#181;g g-1) e de PRO (26,5 ± 0,7 para 29,8 ±0,2 &#181;g g-1), mas diminuiu a adsorção de SIM e não afetou DIA e DEA. No estudo com tempo de contato de 24 h foi possível aplicar modelos de pseudo-primeira e segunda ordem. Os resultados obtidos confirmaram a maior adsorção de PRO, seguidos da ATR. HAT, SIM, DEA e DIA apresentaram as menores taxas de adsorção em solo, sendo que os dois últimos apresentaram uma tendência de dessorção após 4 h de contato, tendo maior potencial de lixiviação para corpos d\'água próximos aos locais de aplicação.<br>This work describes the use of Sequential Injection Liquid Chromatography (SIC) coupled to a long path length optical flow cell with 100 cm long Liquid Core Waveguide (LCW) to improve the limits of detection (LOD) and quantification (LOQ) for determination of atrazine (ATR), propazine (PRO) and simazine (SIM). Separation was achieved with a mobile phase composition of 44:56 (v v-1) methanol:1.25 mM ammonium acetate buffer, pH 4.7, monolithic column and spectrophotometric detection at 238 nm. The values of LOD and LOQ were, respectively, 1.76 and 5.86 &#181;g L-1 for ATR, 4.51 and 15 &#181;g L-1 for PRO and 2.25 and 7.5 &#181;g L-1 for SIM. The LOD values achieved with the employment of long optical path cell were lower than those recommended by US-EPA, which allows for drinking water, maximum concentration levels of 3 &#181;g L-1 for ATR, 4 &#181;g L-1 for SIM and 10 &#181;g L-1 for PRO. Adsorption of SIM, PRO and ATR, as well as their metabolites desisopropylatrazine (DIA), desethylatrazine (DEA) and 2-hidroxyatrazine (HAT) on soil, humic acid and soil modified with humic acidic was studied. An on-line monitoring system was assembled, composed of a tangential filter and a peristaltic pump for circulation of the suspension. Kinetic studies were carried out in two steps, and in both, it was used a mix of compounds with initial concentration of 1,0 mg L-1 and a stepwise gradient elution for separation of the compounds using three mobile phases with compositions of 15 or 28, 40 and 50% (v v-1) methanol: 1.25 mM ammonium acetate buffer, pH 4.7. In the first step the contact time between triazines and adsorbents was 90 minutes. In a second study made only with soil, the contact time was 24 h. Data obtained in the first stage of the study was only fitted to pseudo-second order kinetic equation, which allowed one to estimate the values of the adsorbed mass of triazine per mass of adsorbent. Humic acid was the material with higher adsorptive capacity (from 1470 ± 43 &#181;g g-1 for DIA to 2380 ± 50 &#181;g g-1 for PRO). In soil, PRO exhibited the highest adsorption (26.5 ± 0.1 &#181;g g-1). The presence of humic acid in the soil increased adsorption of ATR (19.4±0.7 to 23±2 &#181;g g-1), HAT (10.9 ± 0.7 to 18 ± 2 &#181;g g-1) and PRO (26.5 ± 0.7 to 29.8 ± 0.2 &#181;g g-1), but decreased adsorption of SIM, not affecting DIA and DEA. In the study with contact time of 24 h, it was possible apply pseudo-first and pseudo-second order equations for SIM, ATR and PRO. The results confirmed the greatest adsorption of PRO, followed by ATR. HAT, SIM, DEA and DIA had low rates of adsorption on soil, the latter two showed a trend of desorption after 4 h of contact, having the greatest potential for leaching to water bodies near to the places of application.

A introdução de separações cromatográficas expandiu a aplicabilidade de sistemas de análises em fluxo. No entanto, a seletividade e sensibilidade de procedimentos são restritos devido à escassa disponibilidade de fases estacionárias que operam a baixas pressões. Sendo assim, foram desenvolvidos quatro procedimentos analíticos visando a melhoria destes aspectos. A primeira proposta explorou pioneiramente colunas de núcleo fundido em sistemas de análises por injeção em fluxo. A separação de metil, etil e propil parabenos foi selecionada com aplicação. As eficiências cromatográficas de quatro colunas (C18, RPamida, F5 e fenil-hexil) foram avaliadas criticamente. Acetonitrila e uma solução de ácido fosfórico pH 2,5 foram utilizadas como fase móvel. A fase RP-amida apresentou melhor desempenho com a separação dos três analitos em 8,0 min, com resoluções > 1,72, simetrias de pico < 1,66, LOD entre 0,12 e 0,39 mg L-1, resposta linear até 5,0 mg L-1 (r > 0,996) e CV para altura dos picos < 3,5 % (n=10). O procedimento foi aplicado à determinação de parabenos em produtos de cuidados pessoais e os resultados concordaram com o procedimento de referência a 95% de confiança. Um procedimento envolvendo o acoplamento de extração em fase sólida (SPE) a um sistema de cromatografia por injeção sequencial (SIC) foi proposto para pré-concentração e separação de oito sulfonamidas. A fase estacionária pentafluorofenilpropil foi selecionada após comparação crítica da eficiência apresentada por três colunas de núcleo fundido e duas colunas de fases monolíticas. Acetonitrila e tampão fosfato (pH 5,0) foram utilizados como fase. Fatores de enriquecimento de até 39,2 foram alcançados com volume de amostra de 500 ?L. O procedimento apresentou tempo de análise < 10,5 min, resoluções > 1,83 com simetrias de pico <= 1,52, LOD entre 4,9 e 27 ?g L-1, faixa de resposta linear entre 30,0 e 1000,0 ?g L-1 (r > 0,997) e CV da altura dos picos, 2,9% (n=6). Um procedimento empregando fase estacionária micelar foi desenvolvido para determinação de melamina em leite. A fase móvel foi composta por uma solução aquosa de dodecil sulfato de sódio (SDS) e 1-propanol (92,5:7,5 v/v). O procedimento de preparo de amostra foi implementado em linha pela diluição da amostra com SDS. Resposta linear foi observada entre 2,0 e 6,0 mg L-1 de melamina com LOD estimado em 0,6 mg L-1 e CV da altura dos picos de 2,9% (n=6). Os resultados para diferentes amostras de leite foram concordantes com aqueles obtidos pelo procedimento cromatográfico de referência em um nível de 95% de confiança. Uma estratégia envolvendo pré-concentração on-column de parabenos em um sistema SIC foi proposta. Resposta linear foi observada entre 0,25 e 1,00 ?g mL-1 (r >= 0,999) e LODs estimados entre 40 e 60 ng mL-1. Tempos de retenção e altura dos picos apresentaram CV < 2,1%. Fatores de enriquecimento entre 30,0 e 34,8 foram alcançados. As estratégias propostas são viáveis para melhoria de seletividade e sensibilidade de separações cromatográficas em sistemas de análises em fluxo, além de apresentarem vantagens frente a procedimentos análogos na literatura<br>The introduction of chromatographic separations expanded the applicability of flow systems. However, selectivity and sensitivity of the procedures are limited due the poor options of stationary phases available for low-pressure. Therefore, four procedures were developed aiming the improvement of these aspects. The first proposal exploited pioneered fused-core columns in a flow injection analysis system. The separation of methyl, ethyl and propel parabens was selected as an application. The chromatographic efficiency of four columns (C18, RP-amide, F5 and fenyl-hexyl) were crítically evaluated. Acetonitrile and a phosphoric acid solution at pH 2.5 were used as mobile phase at different proportions for each column. The RP-amide phase presented the best performance by separating the analytes in 8.0 min with resolution > 1.72, peak symmetry < 1.66, LOD between 0.12-0.39 mg L-1, linear response range up to 5.0 mg L-1 (r > 0.996) and coefficients of variation of peak heights < 3.5% (n=10). The procedure was applied to parabens determination in personal care products and the results agreed with the HPLC reference procedure at the 95% confidence level. A procedure coupling solid phase extraction (SPE) to a sequential injection chromatography (SIC) was proposed for preconcentration and separation of eight sulfonamides. The pentafluorophenylpropyl (F5) phase was selected after a critical comparison of the performance achieved by three fused-core columns and two monolithic columns. Acetonitrile and acetate buffer pH 5.0 were used as mobile phase. Enrichment factors up to 39.2 were achieved with a 500 ?L sample volume. The developed procedure showed analysis time < 10.5 min, resolutions > 1.83 with peak symmetry <= 1.52, LODs between 4.9 and 27 ?g L-1, linear response ranges from 30.0 to 1000.0 ?g L-1 (r > 0.997) and CV of peak heights < 2.9% (n=6). Micelar chromatography was for the first time exploited in SIC and the performance was demonstrated by determination of melamine in milk. Mobile phase was composed by a sodium dodecyl sulfate (SDS) solution and propanol (92.5:7.5). The sample pretreatment procedure was on-line implemented by dilution of the sample with SDS. A linear response was observed within 2.0 and 6.0 mg L-1 of melamine with a LOD estimated at 0.6 mg L-1 and coefficients of variation at 2.9% (n=6). Results for different milk samples agreed with those obtained by high performance liquid chromatography at the 95% confidence level. A procedure involved on-column preconcentration of parabens in a SIC system was based on the injection of relatively high volume of an aqueous sample in a reversed-phase column. After preconcentration, a suitable mobile phase was inserted to perform chromatographic separation (acetonitrile/phosphoric acid pH 2.5 (75:25, v/v)). A linear response was achieved from 0.25 to 1.00 ?g mL-1 (r > 0.999) and LOD estimated within 40 and 80 ng mL-1. Coefficients of variation for retention time and peak heights were below 2.1%. Enrichment factors within 30.0 and 34.8 were achieved. The proposed strategies are feasible for improving selectivity and sensitivity of chromatographic separations in flow analysis systems, besides having advantages compared to similar procedures in the literature

En milieu industriel, si l'analyse en ligne d'effluents gazeux à l'aide de la chromatographie en phase gazeuse est actuellement réalisée sans difficultés majeure, l'analyse des liquides reste une des principales problématiques à résoudre. En effet, comparée à une analyse réalisée au laboratoire, l'analyse en ligne d'un échantillon liquide permettrait de s'affranchir de l'étape de prélèvement et de préparation avant injection ainsi que des problèmes de contamination et de représentativité de l'échantillon. Des systèmes d'injection de liquide en ligne sont actuellement disponibles, cependant, des difficultés d'injection liées à la discrimination des analytes sont rencontrées. C'est dans ce contexte qu'une vanne dédiée à l'injection des liquides en ligne a été développée, puis validée en laboratoire, et enfin mise en œuvre sur des applications industrielles pétrolières. Un tout autre enjeu, lié entre autres à la réduction des coûts de maintenance et d'installation, ainsi qu'à la compatibilité de systèmes analytiques destinés à l'industrie et aux micro-pilotes, a orienté des développements instrumentaux vers la miniaturisation des systèmes. Un assemblage de différentes briques technologiques a ensuite été réalisé afin d'évaluer la faisabilité d'un système miniaturisé incorporant la technologie d'injection des liquides en ligne. Finalement et toujours dans ce contexte de miniaturisation, des colonnes monolithiques courtes ont été mises en œuvre en chromatographie en phase gazeuse à haute pression, au laboratoire pour commencer, puis sur des effluents industriels gazeux. Elles ont permis de réaliser des analyses très rapides avec une grande efficacité par unité de longueur tout en pouvant agir sur la sélectivité des colonnes grâce à un contrôle de leurs propriétés de surface<br>In industry, although on-line analysis of gaseous effluents using gas chromatography is carried out without major difficulty, the analysis of liquids remains problematic and is one of the main issues to be solved. Indeed, compared to an analysis carried out in a laboratory, the on-line analysis of a liquid sample would bypass the steps of sampling and preparation prior to injection and would avoid problems of contamination and representativeness of the sample. Systems for injecting liquids on-line are currently available; however, difficulties are encountered, due to the discrimination of analytes. It is in this context that a valve dedicated to the on-line injection of liquids was developed, validated under laboratory conditions and finally implemented in the oil industry. Another issue, related, amongst other things, to the reduction of maintenance and installation costs, as well as to the compatibility of analytical systems for industry and for micro-pilots, steered instrumental developments towards the miniaturization of systems. Different technological bricks were therefore brought together to assess the feasibility of a miniaturized system involving the technology for on-line injection of liquid. Finally, and still in the context of miniaturization, short monolithic columns were implemented in gaseous phase chromatography at high pressure, first in the laboratory and then on industrial gas effluents. They allowed very fast analyses to be performed which had greater efficiency per unit of length while still being able to act on the selectivity of the columns thanks to the control of their surface properties

Foram desenvolvidas metodologias de cromatografia a líquido de fase reversa baseadas em injeção sequencial (SIC) e em cromatografia a líquido de alta eficiência (HPLC) para determinação de triclosan em amostras de produtos de higiene pessoal e em estudos de adsorção em argilominerais naturais e modificados, visando determinar parâmetros de adsorção de triclosan frente a alguns de seus metabólitos. A determinação de triclosan em enxaguadores bucais foi realizada por SIC com eluição isocrática usando fase móvel constituída por acetonitrila: tampão fosfato de trietilamina 70 mM pH 3,5 na proporção 70:30 (v v-1), obtendo-se limites de detecção e de quantificação de 0,22 e 0,72 mg L-1, respectivamente. Taxas de recuperação entre 96 e 98% foram obtidas da aplicação a amostras reais, sendo que os resultados obtidos pelo método proposto não apresentaram evidências de diferenças estatisticamente significativas em comparação a uma metodologia de referência baseada em HPLC com coluna empacotada. A separação de triclosan (TCS), 2-clorofenol (2-CP), 2,4-diclorofenol (2,4-DCP), 2,4,6-triclorofenol (2,4,6-TCP), 2,3,4-triclorofenol (2,3,4-TCP) e metiltriclosan (MTCS) foi estudada por SIC, obtendo-se a separação de TCS, 2-CP, 2,4-DCP e 2,4,6-TCP com duas etapas de eluição isocrática, a primeira delas com fase móvel 60:40 (v v-1) metanol: tampão acetato de amônio 20 mM (pH 5,5) seguida de eluição com fase móvel 70:30 (v v-1) metanol : tampão acetato de amônio 20 mM (pH 5,5). Nesse caso, os isômeros 2,4,6-TCP e 2,3,4-TCP coeluem. Metiltriclosan, o menos polar desses compostos, pode ser separado de TCS com etapas subseqüentes de eluição. Os métodos foram aplicados para estudar a adsorção de triclosan e seus metabólitos 2,4-DCP, 2,4,6-TCP e metiltriclosan em montmorilonita homoiônica (K+) e modificada com sal de hexadeciltrimetilamônio (HDTMA), observando-se forte adsorção de triclosan e metiltriclosan em comparação a 2-CP, 2,4-DCP e 2,4,6-TCP. A incorporação de HDTMA no argilomineral causou significativo aumento da capacidade de adsorção desses metabólitos, determinada a partir do ajuste dos dados experimentais à equação linearizada de Langmuir, observando-se que a ordem de adsorção é 2,4,6-TCP > 2,4-DCP > 2-CP<br>Reversed-phase liquid chromatography methodologies based on sequential injection (SIC) and high performance liquid chromatography (HPLC) have been developed for determination of triclosan in samples of personal hygiene products and in studies of adsorption on natural and modified clay minerals aiming to determine kinetic and thermodynamic parameters of adsorption of triclosan in comparison with some of its metabolites. The determination of triclosan in oral rinses with SIC was performed by isocratic elution using a mobile phase of acetonitrile : 70 mM triethylamine phosphate buffer pH 3.5 at the ratio 70:30 (v v-1), obtaining limits of detection and quantification of 0.22 and 0.72 mg L-1, respectively. Recovery rates between 96 and 98 % were obtained from the application to commercial samples, and the results obtained by the proposed method showed no evidence of statistically significant differences compared to the reference methodology based on HPLC with packed column. The separation of triclosan (TCS), 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4 trichlorophenol (2,3,4-TCP) and methyltriclosan (MTCS) was studied by SIC, resulting in the separation of TCS, 2-CP, 2,4-DCP and 2,4,6-TCP with two isocratic elution steps, the first of them with a mobile phase 60:40 (v v-1) methanol: 20 mM ammonium acetate buffer (pH 5.5) followed by elution with 70:30 (v v-1) mobile phase of methanol : 20 mM ammonium acetate buffer (pH 5.5). In this case, the isomers 2,4,6-TCP and 2,3,4-TCP coeluted. Methyltriclosan, the less polar of these compounds, can be separated from TCS with subsequent elution steps. The methods were applied to study the adsorption of triclosan and its metabolites 2-CP, 2,4-DCP, 2,4,6-TCP and methyltriclosan on homoionic montmorillonite (K+) as well as in hexadecyltrimethylammonium salt (HDTMA) modified montmorillonite, noticing a stronger adsorption of triclosan and methyltriclosan compared with 2-CP, 2,4-DCP and 2,4,6-TCP. Incorporation of HDTMA in the clay mineral caused significant increase in adsorption capacity of these metabolites. This capacity was determined by fitting the experimental data to the linearized Langmuir equation. The adsorption order was 2,4,6-TCP > 2,4-DCP > 2-CP.

by John K. McFarlane and Philip M. Gschwend.<br>Includes bibliographical references.<br>Sponsored by Northeast Utilities Service Company, Southern California Edison Company, Empire State Electric Energy Research Corporation, American Power Service Company, Standard Oil Company and New England Power Service Company under the MIT Energy Laboratory Utilites Program.

碩士<br>輔仁大學<br>化學學系<br>81<br>Analysis of heavy-metal ions by using AA and HPLC was widely done in the past decades but the use of GC in analyzing heavy- metal ions was rarely heard of. Therefore, we decided on a simple, time-saving and highly accurate method of using GC in the analysis of several heavy-metals ions. We used Chelex-100 resin for pre-concentration of heavy-metals in the smaple. It has a high chelating selectivity which makes it suitable for separating traces of heavy metals from the other major alkali and alkaline-earth metals. Standard heavy metals were spiked into deionized water and the solution was then passed through two minicolumns packed with Chelex-100. Columns each 2g of resin in the ammonium from with a flow rate of 0.8-1.0 ml/min were found to be the best condition for the preconcentration of Cd、Co、Cu、Hg、Mn、Ni、Pb and Zn in the water whose pH value had been adjusted to 6.50. The trace metals were then concentrated after being chelated with sodium diethyldithiocabamate and then extracted form the water by chloroform. Finally, we applied the above method to the natural water of Da-Han Stream and the quantitative results were compared to that of AA. GC/MS was also used as a further confirmation of identifi- cation. The use of GC in the analysis of heavy-metal ions will be an interesting challenge for further investigation.

Für eine effiziente und nachhaltige Nutzung von Georeservoiren sind bestmögliche Reservoirmanagementverfahren erforderlich. Oft setzen diese Verfahren auf Tracer-Tests. Dabei enthalten die aufgezeichneten Tracersignale integrale Informationen der Reservoireigenschaften. Tracer-Tests bieten somit eine leistungsfähige Technik zur Charakterisierung und Überwachung der bewirtschafteten Georeservoire. Im Gegensatz zu Tracer-Tests mit konservativen Tracern, welche bereits etablierte Testroutinen zur Verfügung stellen, ist die Verwendung von reaktiven Tracern ein neuer Ansatz. Aufgrund unpassender physikalisch-chemischer Modelle und/oder falschen Annahmen ist die Analyse und Interpretation von reaktiven Tracersignalen jedoch oft verzerrt, fehlinterpretiert oder sogar unmöglich. Reaktive Tracer sind dennoch unersetzbar, da sie durch die gezielte Ausnutzung selektiver und spezifischer Reaktionen mögliche Metriken von Reservoirtestverfahren auf einzigartige Weise erweitern. So liefern reaktive Tracer für ein integriertes Reservoirmanagement geforderten Aussagen über Reservoirmetriken wie z.B. Wärmeaustauschflächen oder in-situ Temperaturen. Um Unsicherheiten bei der Auswertung von Tracerexperimenten zu reduzieren, werden theoretische und experimentelle Untersuchungen zu hydrolysierenden Tracern vorgestellt. Diese Tracer sind durch ihre Reaktion mit Wasser charakterisiert. Einerseits können sie als thermo-sensitive Tracer Informationen über Temperaturen und abgekühlte Anteile eines beprobten Reservoirs liefern. Für die Interpretation von thermo-sensitiven Tracerexperimenten sind die Kenntnis der zugrunde liegenden Reaktionsmechanismen sowie bekannte Arrhenius-Parameter Voraussetzung, um die verwendete Reaktion pseudo erster Ordnung nutzen zu können. Darüber hinaus ermöglichen die verwendeten Verbindungen durch ihre Fluoreszenzeigenschaften eine Online-Messung. Um die Empfindlichkeit und praktischen Grenzen thermo-sensitiver Tracer zu untersuchen, wurden kontrollierte Laborexperimente in einem eigens dafür entwickelten Versuchsaufbau durchgeführt. Dieser besteht aus zwei seriell geschalteten Säulen, die beide mit Sand gefüllt sind und jeweils auf eine eigene Temperatur eingestellt werden können. Somit ist es möglich, verschiedene thermische Einstellungen zu betrachten. Die untersuchten experimentellen Szenarien imitieren größtenteils Feldanwendungen: Durchflussexperimente sowie auch Experimente mit einer Umkehr der Fließrichtung. Darüber hinaus wurde untersucht, ob thermo-sensitive Tracer auch sensitiv gegenüber der Position der Temperaturfront sind. Dabei wurden die Tracer kontinuierlich oder gepulst injiziert. Die Ergebnisse bestätigen die zugrunde liegende Theorie experimentell. Wenn die pH-Abhängigkeit der Hydrolyse bei der Analyse berücksichtigt wird, kann eine Temperaturschätzung mit einer Genauigkeit und Präzision von bis zu 1 K erreicht werden. Die Schätzungen sind von Verweilzeit und gemessenen Konzentrationen unabhängig. Weiterhin lässt sich eine Schätzung über den ausgekühlten Anteil des Systems erhalten. Durch die steuerbaren und definierten Laborbedingungen ist es erstmals möglich, die geforderte Anwendbarkeit von thermo-sensitiven Tracern belastbar nachzuweisen. Des Weiteren wird eine zweite Anwendung hydrolysierender Tracer vorgeschlagen. Beim Lösen von CO2 für „Carbon Capture and Storage“-Anwendungen hängt die Effizienz maßgeblich von der Grenzfläche zwischen CO2 und der Sole in tiefen Reservoiren ab. Somit ist diese Metrik wichtig, um die Effizienz der CO2 Auflösung in Wasser zu bewerten. Die gezielt entwickelten Kinetic-Interface-Senitive-Tracer (KIS-Tracer) nutzen, zusätzlich zur Hydrolyse an der Grenzfläche, die unterschiedlichen Lösungseigenschaften von Tracer und Reaktionsprodukt im entsprechenden Fluid. Somit lassen sich potentiell Aussagen über die Dynamik der Grenzfläche machen. Neben dem grundlegenden Konzept sowie den theoretischen Tracer-Anforderungen wird eine erste Anwendung im Laborexperiment vorgestellt. Diese zeigt das erfolgreiche, zielorientierte Moleküldesign und bietet eine experimentelle Basis für ein makroskopisches numerisches Modell, mit welchem numerische Simulationen verschiedener Testszenarien durchgeführt werden, um das Zusammenspiel von KIS-Tracer und dynamischer Grenzfläche zu untersuchen. Aufgrund der Temperaturabhängigkeit der Reaktionsgeschwindigkeit hydrolysierender Tracer werden in der Regel auch thermische Signale aufgezeichnet. Der letzte Teil prüft die Möglichkeit, Informationen aus den aufgezeichneten Temperaturen zu extrahieren. Für ein idealisiertes Einzelkluftsystem wird eine Reihe von analytischen Lösungen diskutiert. Aus thermischen Injektion-/Entzugsversuchen können damit räumliche und zeitliche Profile abgeleitet werden. Mit der Verwendung von mathematisch effizienten Inversionsverfahren wie der iterativen Laplace-Transformation lassen sich rechentechnisch effiziente Realraum-Lösungen ableiten. Durch die Einführung von drei dimensionslosen Kennzahlen können die berechneten Temperaturprofile auf Bruchbreite oder Wärmetransportrate, wechselnde Injektions-/ Pumpraten und/oder auf in der Nähe beobachtbare räumliche Informationen analysiert werden. Schließlich werden analytische Lösungen als Kernel-Funktionen für nichtlineare Optimierungsalgorithmen vorgestellt. Zusammenfassend bearbeitet die vorliegende Arbeit den Übergang zwischen Tracerauswahl und Traceranwendung. Die Ergebnisse helfen Planungs- und Analyseunsicherheiten zu reduzieren. Dies wird bezüglich der Empfindlichkeit gegenüber Temperaturen, Kühlungsanteilen, flüssig/flüssig-Grenzfläche, Kluftbreite und Wärmetransportrate gezeigt. Somit bieten die vorgestellten Tracerkonzepte neue Metriken zur Verbesserung von Reservoirmanagementverfahren. Die experimentellen Ergebnisse und die neuen analytischen Modelle ermöglichen einen tiefen Einblick in die kollektive Rolle der Parameter, welche die Hydrolyse und den Wärmetransport in Georeservoiren kontrollieren.