Chaque année en France, les semenciers sont contraints de déclasser plus de 10 000 tonnes de semences. Ces semences sont actuellement incinérées dans des cimenteries au frais des semenciers et non valorisables dans des procédés de valorisation des agro-ressources, compte tenu de leur teneur non négligeable en pesticides. Par conséquent, il apparaît nécessaire de réduire, dans un premier temps, la quantité de produits phytosanitaires présents dans les enrobages avant de pouvoir valoriser ces semences déclassées.L’objet de cette thèse consiste donc à développer un outil permettant de décomposer une grande partie des produits phytosanitaires présents sur les enrobages par ozonation. Dans un premier temps, une méthode d’extraction par liquide pressurisé a été développée pour la quantification des produits phytosanitaires présents sur les enrobages avant et après ozonation. Cette méthode d’extraction a été validée et a permis de déterminer, par la suite,l’efficacité du traitement d’ozonation sur les semences enrobées.Ensuite, afin d’évaluer l’efficacité d’un traitement à l’ozone, deux pesticides présents dans la solution d’enrobage Gaucho Blé® -l’imidaclopride et le bitertanol- ont été ozonés, en solution aqueuse dans un réacteur agité. Les deux produits ont été dégradés complètement en moins de 30 minutes et la loi cinétique de leurs réactions d’ozonation a montré que l’ordre partiel de la réaction a été de 1 pour l’ozone et pour le pesticide. Les produits de dégradation,formés au cours de l’ozonation, ont aussi été analysés par spectrométrie de masse ESI(+)-MSet la structure de la plupart des produits de dégradation a été déterminée. Un schéma des différentes voies de dégradation de l’imidaclopride et du bitertanol a pu être proposé.Enfin, l’ozonation des pesticides a été étudiée sur les semences de blé tendre enrobées avec la solution de Gaucho Blé® dans un réacteur à lit fixe. L’humidification des grains avant ozonation, la concentration en ozone dans le gaz et la durée de traitement ont semblé être les facteurs importants pour accélérer la cinétique de dégradation des pesticides dans les enrobages. Les pesticides ont été dégradés (respectivement 99 et 90 % de dégradation pour l’imidaclopride et le bitertanol). La loi cinétique de la réaction d’ozonation de l’imidaclopride et du bitertanol a présenté des ordres partiels égaux à 1 pour l’ozone et pour le pesticide. Ce procédé a ensuite été appliqué à d’autres types de semences enrobées et s’est avéré efficace sur tous les principes actifs étudiés. Enfin, les semences enrobées ont été ozonées dans un réacteur prototype (réacteur à plateau vibrant) dans lequel tous les pesticides étudiés ont été dégradés mais à des taux de dégradation plus faibles qu’en réacteur à lit fixe. / Every year in France, seed producers must downgrade more than 10,000 tons of seeds. These seeds are currently incinerated in cement factories at seed producers’ expenses and non available for the processes of valorization of renewable resources, due to their significant pesticide content. Consequently, in the first step, the quantity of pesticides present in the seed loading must be reduced before a subsequent valorization of the downgraded seeds. The purpose of this PhD work is thus to develop a process for the decomposition of a large amount of the pesticides present in the seed loading. First, an extraction procedure by pressurized liquid was developed for the quantitation of phytopharmaceuticals present on the loading before and after the ozonation. This extraction method was validated and enabled to determine, subsequently, the efficiency of the ozonation process on the loaded seeds. In the second time, in order to evaluate the efficiency of an ozonation treatment, both pesticides present in the Gaucho Blé® seed loading solution – imidacloprid and bitertanol – were ozonated, in aqueous solutions in a stirred reactor. Both compounds were completely decomposed in 30 minutes and the kinetic law for the ozonation of both compounds displayed a partial order of 1 for ozone and 1 for the pesticide. Degradation products, formed during the ozonation, were analyzed by mass spectrometry ESI(+)-MS and the structure of most of the compounds was characterized. Degradation pathways for imidacloprid and bitertanol were thus proposed. Finally, the ozonation of pesticides were applied to soft wheat seeds loaded with Gaucho Blé® loading solution, in a fixed bed reactor. The humidification of seeds before ozonation, the concentration of ozone in the inlet gas and the ozonation time were the predominant factors to accelerate the kinetic of degradation of pesticides in the seed loadings. The pesticides were successfully decomposed (respectively 99 and 90 % for the degradation of imidacloprid and bitertanol). The kinetic laws for the ozonation reactions of imidacloprid and bitertanol were determined and the partial orders of the reaction were 1 for both ozone and the pesticide. This process was then applied to the treatment of other loaded seeds and showed good degradation rates for all the studied pesticides. Subsequently, the loaded seeds were ozonated in a prototype reactor equipped with a dynamic plate in which all the pesticides were decomposed but with lower degradation rates than in a fixed bed reactor.

Gold Nanoclusters are of particular interest due to their many possible applications across a wide range of scientific fields. More specifically, nano-sized gold particles have potential to be used in drug delivery systems, cancer therapy and catalysis. This dissertation focuses on improving our understanding of ligated gold nanoclusters by examining the role of a variety of phosphine based ligands, novel methods to produce monodisperse solutions, and investigating the kinetics of water soluble ligated gold nanoclusters. The addition of ligands to solutions of Au have shown to produce small (< 20 Au atoms) clusters. All nanocluster solutions were prepared in a similar manner. Typically, a gold salt, either Chloro(triphenylphosphine) gold(I) (Au(PPh3)Cl), or Potassium gold (III) chloride (KAuCl4), were dissolved in various solvents. Next, an equal concentration of ligand was added to the solution and stirred until completely dissolved. Finally, all were reduced with 5X the concentration of borane-tert-butylamine (BTBC) after which were sonicated for ~20 minutes. The timing and method of adding the ligands and reducing agent varied depending on the solution and solubility of the ligands. Primarily we used Electrospray Ionization Mass Spectrometry (ESI-MS) and Ultraviolet – Visible Spectroscopy (UV-VIS) for the characterization of samples, however, occasionally Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) and X-Ray Photoemission Spectroscopy (XPS) were used. The most recent research took advantage of the size selective nature of an alpha hemolysin (a-HL) nanopore to investigate the kinetics of thiol-ligated Au clusters ~2 nm in size. The relationship between ligand rigidity and solvent polarity and the size and dispersity of Au cluster suspensions was investigated. We observed the formation of stable monodisperse clusters with the shortest ligand, (L3), independent of solvent. With a longer flexible ligand, (L6), we observed primarily Au8-10 cores depending on the ratio of L6/PPh3. All other ligands yielded polydisperse distributions. These dispersions contained clusters with a nuclearity between 8 and 11, for example [Au10(PPh3)9]3+ in LBn and [Au8(PPh3)7]2+ in LBp, were observed in the initial stages, but they were not stable and precipitated out or plated the glass vial. We also observed that the polarity of the solvent did not play a significant role in the formation of MPC’s, however a correlation between the size of the solvent and MPC formation was observed. The growth and evolution of two unique gold structures was also observed via UV-Vis and ESI-MS. Solutions were prepared which contained Potassium gold (III) chloride and PPh2(CH2)3PPh2, i.e., 1,3-bis(diphenylphosphino)propane, denoted by L3, reduced with Borane tert-butylamine complex (BTBC) in a 1:1 diethyl ether:methanol mix, which yielded a stable [Au11(L3)5]+3. Starting with this known Au11 solution, the addition of Mn2+ has shown to lead to the formation of a stable diphosphine ligated Au8 and a new Au14 species. Additionally, we show that the co-reduction of NiCl2 and Au in the absence of the ligand (L3) does give us a simple method for the production of a monodisperse [Au9(PPh3)8]2+ cluster solution and via electroless deposition does give us a potential low temperature pathway to the formation of a AuNi nanoalloy particle.

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Orientador: Pedro de Magalhães Padilha / Resumo: Devido a sua grande concentração de nutrientes, tais como proteínas, vitaminas e minerais, o peixe é considerado um dos alimentos mais saudáveis que se pode encontrar na natureza. No entanto, a ingestão de peixes é considerada a forma predominante de via de exposição do ser humano ao mercúrio (Hg), principalmente para as populações que vivem às margens dos rios, onde o peixe constitui a principal fonte de proteína. Na tentativa de elucidar os mecanismos de toxicidade das espécies mercuriais, o teor desse metal tem sido estudado intensamente pela comunidade científica nas últimas décadas em amostras de solo, sedimentos, humanos e peixes na Amazônia brasileira. Sabe-se que as espécies mercuriais bioacumuladas nos tecidos dos seres vivos ligam-se a metaloproteínas, e quando há uma concentração alta de metal tóxico nos organismos, esses passam a expressar proteínas de defesa, denominadas metalotioneínas (MTs) responsáveis pelo transporte e eliminação de metais tóxicos. Apesar de estudos mostrarem o aumento das metalotioneínas em animais expostos a metais potencialmente tóxicos, essas proteínas não foram caracterizadas para confirmação de sua veridicidade, são analisadas por métodos indiretos, esse fato leva a necessidade de técnicas mais precisas na identificação de metalotioneínas. Levando em consideração o exposto esse estudo teve como objetivo otimizar métodos de quantificação de mercúrio e técnica de eletroforese para identificação de possíveis metalotioneínas biomarcadoras d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Due to its high concentration of nutrients, such as proteins, vitamins and minerals, fish is considered one of the healthiest foods that one can find in nature. However, fish intake is considered to be the predominant human exposure pathway to mercury (Hg), especially for populations living along riverbanks where fish are the main source of protein. In the attempt to elucidate the toxicity mechanisms of mercurial species, the content of this metal has been intensively studied by the scientific community in recent decades in soil, sediment, human and fish samples in the Brazilian Amazon. It is known that mercurial species bioaccumulated in the tissues of living beings bind to metalloproteins, and when there is a high concentration of toxic metal in organisms, they begin to express defense proteins, called metallothioneins (MTs) responsible for the transport and elimination of Toxic metals. Although studies have shown the increase of metallothioneins in animals exposed to potentially toxic metals, these proteins have not been characterized to confirm their veridicity, are analyzed by indirect methods, this fact leads to the need for more precise techniques in the identification of metallothioneins. Taking into account the above, this study aimed to optimize mercury quantification methods and electrophoresis technique for identification of possible mercury biomarkers metallothionein in muscular and hepatic tissue of fish of economic interest, Tucunaré (Cichla spp.), Filhote (Bra... (Complete abstract click electronic access below) / Doutor

Orientador: Pedro de Magalhães Padilha / Resumo: O peixe é uma importante fonte de proteínas de alto valor biológico, vitaminas e minerais. Porém, este alimento é também uma das principais vias de exposição humana a contaminantes tóxicos como o metilmercúrio (MeHg). Assim a sua acumulação no peixe pode predispor sérios riscos para a saúde humana. As altas concentrações de mercúrio encontrados em solo, sedimentos, peixes e humanos na Amazônia brasileira têm sido estudados intensamente pela comunidade científica nas últimas décadas, procurando-se elucidar os mecanismos de toxicidade das espécies mercuriais. As espécies mercuriais ligam-se preferencialmente às proteínas. Podendo significar que a fração biodisponível das espécies mercuriais nas diferentes espécies de peixes pode ser dependente da forma como estas estão ligadas a essas proteínas. Portanto esta proposta de trabalho buscou otimizar procedimentos eletroforéticos por 2D-PAGE para fracionamento e identificação de proteínas responsáveis pelo transporte de mercúrio em amostras de tecido muscular e hepático de peixes coletados no reservatório da Usina Hidrelétrica de Jirau – no rio Madeira; utilizando o método de espectrometria de absorção atômica em forno de grafite (GFAAS), para determinação de mercúrio nos tecidos e spots proteicos obtidos; avaliou o estresse oxidativo dos peixes contaminados com mercúrio por meio das atividades das enzimas catalase (CAT), glutationa peroxidase (GSH-Px) e superóxido dismutase (SOD), bem como das concentrações de hidroperóxido de lipí... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Orientador: Marcos Nogueira Eberlin / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-07T11:19:58Z (GMT). No. of bitstreams: 1 Marques_LygiadeAzevedo_M.pdf: 2432568 bytes, checksum: 7bf6003b0fa0df13e1ba0f91d7ebf00b (MD5) Previous issue date: 2006 / Resumo: Neste trabalho aplicamos técnicas avançadas de espectrometria de massas, (MALDI-TOF e ESI-MS) na análise de micotoxinas em alimentos e na tipificação e verificação de fraudes em perfumes. Aplicamos a técnica MALDI-TOF em análises de micotoxinas, e esta mostrou excelente desempenho nas análises de aflatoxinas e ocratoxina e vantagem sobre a técnica de escolha atual, o método ELISA. Esta vantagem é principalmente maior especificidade através de maior exatidão em medidas de massas e, portanto, maior confiabilidade. O Planejamento de experimento foi uma ferramenta valiosa para obtenção das melhores condições e estudo dos parâmetros de interferência. O limite de detecção encontrado para a técnica foi da ordem de 25 pg para aflatoxinas e de 1 ng para ocratoxina, com perspectiva de melhoria através de aumento da massa amostral em estudos futuros para adaptação da metodologia de extração na matriz de interesse à técnica MALDI-TOF. A técnica ESI-MS foi utilizada para a tipificação e detecção de perfumes proporcionando, através da análise de componentes principais (PCA), a diferenciação com segurança entre perfumes originais, falsos e inspirados, utilizando como indicadores componentes polares não majoritários característicos de cada categoria avaliada. Este estudo abre caminho para que esta técnica seja utilizada na avaliação de perfumes que estão sob suspeita de falsificação com auxilio de uma biblioteca de "fingerprint" de perfumes por ESI-MS. O emprego da técnica de MALDI-TOF também é uma opção vantajosa para o monitoramento da qualidade de grãos quanto a presença de toxinas indesejáveis, bem como ameaças de bioterrorismo. / Abstract: In this work we applied advanced mass spectrometry techniques (MALDI-TOF and ESI-MS) to micotoxin analysis in food and for the typification and detection of counterfeit perfumes. MALDI-TOF was applied to micotoxin analysis, which showed excellent performance for the analysis of aflatoxins and ochratoxin with advantage over the current technique of choice, the ELISA method. This advantage is mainly its greater specifity due the exactness of the measurements, therefore with higher reliability. The surface analysis was a valuable tool to attain the best conditions and study the interference of several parameters. The detection limit found for the technique was 25 pg for aflatoxins and 1 ng for ochratoxins, with perspective of improvement through increase of the sample mass in future studies for adaptation of the methodology of extration in the matrix of interest for the MALDI-TOF technique. The ESI-MS technique was used for typification and detection of counterfeit perfumes, providing, through principal component analysis (PCA), the characterization of original, counterfeit and inspired perfumes, using as minoritarian polar compounds as diagnostic ions of each perfume category evaluated. We envisage that the method can be used to establish a ESI-MS fingerprinting library of perfumes for comparison with those from samples under investigation, and that such a library could be updated constantly by the addition of ESI-MS of new perfumes even before they are commercially released. MALDI-TOF technique is also an advantageous option for the monitoring of crop quality relating to the presence of undesirable toxins, as well as bioterrorism threats by micotoxin poisoning. / Mestrado / Quimica Analitica / Mestre em Química