Orientador: Carol H. Collins / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-08T05:15:55Z (GMT). No. of bitstreams: 1 Auler_LuciaMariaLaboissieredeAlencar_D.pdf: 1289805 bytes, checksum: c5c314fa95e1f395031bfe5e731325d3 (MD5) Previous issue date: 2006 / Resumo: Uma nova fase estacionária foi desenvolvida utilizando a sílica como suporte, para aplicação em Cromatografia por Troca Iônica na separação de ânions. A preparação desse suporte cromatográfico envolveu a modificação da sílica com cloropropiltrimetoxissilano seguido pela reação com a piridina para produzir 0,5 mmol g de grupos propilpiridínio carregados positivamente sobre a superfície da sílica. Esses grupos atuam como sítios de troca aniônica durante a separação cromatográfica. A nova fase foi caracterizada por análise elementar, espectroscopia na região do infravermelho, ressonância magnética de C e Si no estado sólido e por cromatografia. A capacidade de troca da sílica modificada foi determinada pela concentração de íons cloreto trocáveis, por meio da análise por ativação neutrônica . O estudo da estabilidade química do suporte cromatográfico, nas mesmas condições da separação, demonstra que a fase, mesmo sem nenhuma proteção, é estável até 12000 volumes de coluna. A avaliação dos parâmetros cromatográficos das separações realizadas em um sistema com detecção por condutividade, sem supressão mostra que a sílica com o grupo propilpiridínio quimicamente ligado é uma fase estacionária bastante promissora para a separação de ânions em amostras contendo baixos teores dessas espécies / Abstract: A new stationary phase based on silica was developed for application in Ion Exchange Chromatography for anion separation. The preparation of the new phase involved silanization of chromatographic silica particles with chloropropyl-trimethoxysilane to yield chloropropyl silica. The modified silica was then reacted with pyridine to produce positively charged propylpyridinium groups on the surface, which are the anion exchange sites. The new phase was characterized by elemental analysis and infrared and solid state C and Si NMR spectroscopies. The exchange capacity of the modified silica was investigated by determining its exchangeable chloride content using neutron activation analysis. The stability of this phase, tested under the same conditions as for the separation, shows that this phase, although without protection, is stable to 12000 column volumes. Chromatographic parameters evaluated using unsuppressed conductivity detection indicate that the chloropropylpyridiniun silica is promising for separation and quantification of anions in samples with low concentrations of these species / Doutorado / Quimica Analitica / Doutor em Ciências

The biopharmaceutical industry is constantly developing biological drugs, resulting in increased levels of product related impurities having similar characteristics as the target. The aim of the ligand project was to address future challenging purifications by developing new ligands for future resins for the biopharmaceutical industry. The purpose of this study was to develop a high-throughput screening method and use it to compare 15 novel multimodal anionic exchange ligand analogues with two reference ligands, for future polishing steps in the downstream process. The protein binding behavior of the ligands were studied with alkaline phosphatase, human serum albumin, α-chymotrypsinogen A and a monoclonal antibody as model proteins, at various pH values and salt concentrations. The selection process of the model proteins was based on stability studies, a study of their adsorption to the 96 well plate, and their binding behavior on three of the ligand analogues and one reference ligand. The percent protein bound to the ligands at the various conditions was calculated and presented in plots in order to study their binding behaviors. The calculated values were also used in order to evaluate the results in principal component analysis, creating chromatographic diversity maps. The maps were used to get an overview of the differences and similarities of the ligand analogues compared to the reference resins, which can be used for selecting ligands for future research and biomanufacturing. Four analogues and one reference ligand were also studied in a column format where different gradients were used, which confirmed the obtained results in the plate experiments.

The objective of this work is to advance the mechanistic understanding of cathodic electrocoating. These efforts are focused on the initial processes responsible for deposition, which are examined through direct experimentation and simulation. Electrocoating is a global industrial process providing a corrosive resistant base paint to automobile bodies. Presently, empirical models are used to model coating thickness; these models tend to overpredict deposition in occluded areas. Convection is implemented to study the behavior of adhered surface H2 bubbles on the substrate surfaces. The impact of surface H2 bubbles and early e-coat deposition on the local current density is studied using simulations. Results show an increased local current density around surface H2 bubbles and early e-coat deposition influences film growth. When surface H2 bubbles are displaced before sufficient e-coat is deposited the lack of increased local current density slows deposition. However, when sufficient e-coat is deposited and then surface H2 bubbles are displaced, the induction period is unaffected since the early deposition is sufficient to keep the local current density high enough to drive deposition. Solution factors are qualitatively studied using a diluted e-coat dispersion and a anionic exchange membrane cell. Experiments demonstrate a visual change in the solution near the cathode and indicates a coagulation of micelles in this region. Experiments also demonstrate a rise in pH is associated with the induction time, but is not necessary for e-coat deposition. Film resistance is used to understand film growth and film morphology during industrial electrocoating. Interruption experiments demonstrate H2 bubbles may influence film resistance. Film density and resistivity results cannot be completely explained with understood physics, underlining the importance of future resistance studies. These results provide an increased understanding of fundamental processes responsible for initial deposition, which is the foundation needed for advanced physics-based models of the electrocoating process.

Ce travail de thèse s'intéresse à la relation entre la composition des phases Hydroxydes Doubles Lamellaires (HDL) et leurs propriétés structurales. La première partie de ce manuscrit est consacrée à la formation et aux propriétés structurales de ces matériaux. L'effet de la nature des cations (MgII, NiII, CoII ; AlIII, FeIII) et de leur stoechiométrie dans le feuillet (MII/MIII E [2 ; 10]) constitue les axes principaux de ces travaux. L'étude du comportement hydrolytique d'un mélange de cations divalents et trivalents en fonction de leurs proportions en solution a permis de proposer un mécanisme topotactique de formation de ces phases HDL. Il a aussi été montré que la variabilité stoechiométrique du feuillet ne dépend que de la nature des cations. Ainsi, des modèles électrostatiques ont été proposés afin de rationaliser et prédire la gamme de composition de ces phases HDL en fonction de la nature des cations. La seconde partie est dédiée aux propriétés du milieu interfoliaire. Une étude couplant des analyses par spectroscopies vibrationnelles infrarouge et Raman et par diffraction des Rayons X a permis d'apporter une description précise de l'influence de la nature des cations, et de leurs stoechiométries sur l'organisation des anions dans le milieu interfoliaire (Cl-, CO32-, NO3-, ClO4-, acides aminés). Le rôle de l'eau dans ces phases a également été étudié. Dans le cas des hybrides organo-minéraux, il a été montré que la charge dicte l'orientation des acides aminés intercalées et par conséquent, leur réactivité envers la formation de la liaison peptidique. Également, les propriétés énantioselectives du domaine interfeuillet sont mises en avant pour la formation de peptides / This manuscript is devoted to the comprehension of the relationship between the composition of Layered Double Hydroxides (LDH) and their structural properties. The first part of this manuscript is focalized on the formation and the structural properties of these materials. The influence of the cationic nature (MgII, NiII, CoII ; AlIII, FeIII) and their stoichiometries within the layer (MII/MIII E [2 ; 10]) constitutes the main axis of these investigations. The study of the hydrolytic behavior of a solution containing a mixture of divalent and trivalent cations as a function of their relative proportion allowed to propose a topotactic mechanism of formation of LDH phases. Moreover, it has been showed that the composition range is solely dependent on the nature of the cations. Thus, electrostatic models were designed to rationalize and predict the composition range as a function of the cationic nature. The second part is concerned with the properties of the interlayer domain. A joint study, coupling vibrational spectroscopies (Infrared and Raman) and X-ray diffraction allowed a detailed description of the influence of the cations and their stoichiometries on the organization of the interlayer anions (Cl-, CO32-, NO3-, ClO4-, aminoacids). The role of the interlayer water has also been investigated. Concerning hybrid organo-minerals, it has been showed that the layer charge dictates the orientation of the interlayered aminoacids, and consequently, their reactivity toward the formation of the peptide bonds. The enantioselective properties of the interlayer domain are highlighted toward the formation of peptides