Fundação de Amparo a Pesquisa no Estado do Rio Grande do Sul / This work aimed the preparation of novel nanocapsules and nanoemulsions based on pracaxy oil loaded with ubiquinone. For nanocapsules, poly(-caprolactone) (PCL) or Eudragit® EPO were employed in the preparation. For comparison purposes, nanospheres containing ubiquinone were prepared with both polymers. The methods employed to prepare these formulations were spontaneous emulsification (nanoemulsions), nanoprecipitation (nanospheres) and interfacial deposition of pre-formed polymer (nanocapsules). An analytical method was validated to the assay of ubiquinone-loaded systems and it was considered specific, linear, precise and accurate. After preparation, the nanostructured systems were characterized regarding particle size, polydispersity index, zeta potential, pH, as well as ubiquinone content and encapsulation efficiency. PCL-nanocapsules presented larger diameters (261 nm), which demonstrates the influence of both oil and polymer in the formulation. Nanocapsules containing the lowest amount of oil (0.15 g) presented polydispersity index more suitable. Zeta potential values of both nanoemulsions (-18 mV) and PCL-nanoparticles (-12 to -21 mV) were negatives, due to the presence of fatty acids in the pracaxy oil and due to the negative density of charge of PCL, respectively. Nanocapsules and nanospheres formulated with Eudragit ® EPO showed positives values of zeta potential (+25 to +45 mV), because of the cationic nature of this polymer. The pH values were slightly acidic for both nanoemulsions and PCL-nanostructures, while the Eudragit® EPO formulations presented pH close to the neutrality, about 7.5. Ubiquinone content of the nanostructured systems was close to the theoretical value, 1.0 mg/mL and the encapsulation efficiency was about 100%. Photodegradation studies showed that nanostructures were able to provide protection to the encapsulated ubiquinone in relation to free-ubiquinone (ethanolic solution), after 4h of exposition to UVC radiation and this protection was more pronounced for nanocapsules and nanoemulsions. The drug degradation followed a first order kinetic for all the systems studied, while the ethanolic solution of ubiquinone fitted better to the second order equation. The stability study of the formulations demonstrated that the systems were instable when stored for 90 days at 40 ± 2ºC e UR 75 ± 5%, especially Eudragit® EPO-nanocapsules, however, when they were stored at room temperature, the formulations appeared to be stable, keeping the initial physico-chemical characteristics. By performing a semi-quantitative hemolysis test, it was demonstrated the hemocompatibility of PCL nanocapsules. The MTT test was used to evaluate the cytotoxicity, and it was verified that free ubiquinone and pracaxi oil were capable to reduce cellular viability in rat glioma (C6) and breast cancer cells (MCF-7) after 48h of incubation, comparing to the control (DMEM). Besides, this cytotoxic potential was more pronounced when the cells were treated with PCL nanocapsules. In this way, the nanocarriers developed are promising systems for vectorization, stabilization and to study therapeutic potentials of ubiquinone. / Este trabalho objetivou a preparação inédita de nanocápsulas e nanoemulsões à base de óleo de pracaxi contendo ubiquinona. Para as nanocápsulas, a poli(-caprolactona) (PCL) ou o Eudragit® EPO foram usados na preparação. Comparativamente, nanoesferas contendo ubiquinona foram preparadas com ambos os polímeros. Como método de preparo utilizou-se a emulsificação espontânea (nanoemulsões), a nanoprecipitação (nanoesferas) e a deposição interfacial de polímero pré-formado (nanocápsulas). A metodologia analítica para quantificação da ubiquinona nos sistemas foi validada, sendo o método considerado seletivo, linear, preciso e exato. Após a preparação, os sistemas nanoestruturados foram caracterizados quanto ao diâmetro médio de gotícula/partícula, índice de polidispersão, potencial zeta e pH, bem como teor e eficiência de encapsulamento da ubiquinona. As nanocápsulas de PCL apresentaram os maiores diâmetros (261 nm), demonstrando a influência da presença do óleo e do polímero na formulação, sendo que índices de polidispersão mais adequados foram obtidos nas dispersões contendo menor concentração de óleo de pracaxi (0,15g). Os valores de potencial zeta tanto das nanoemulsões (-18 mV) quanto das nanopartículas (-12 a -21 mV) de PCL foram negativos, devido à presença de ácidos graxos no óleo de pracaxi e pela densidade de carga negativa da PCL, respectivamente. As nanocápsulas e nanoesferas de Eudragit® EPO apresentaram potencial zeta positivo (+25 a +45 mV), pois este polímero é catiônico. Tanto para as nanoemulsões quanto para as nanoestruturas à base de PCL os valores de pH foram levemente ácidos, enquanto que para as formulações de Eudragit® EPO as médias foram mais próximas da neutralidade, em torno de 7,5. O teor de ubiquinona nos sistemas nanoestruturados foi próximo ao teórico, 1,0 mg/mL (com exceção das nanoesferas de Eudragit® EPO) e a eficiência de encapsulamento do fármaco nos sistemas foi de aproximadamente 100%. Estudos de fotodegradação demonstraram que as nanoestruturas foram capazes de promover proteção à ubiquinona encapsulada em comparação ao fármaco livre (solução etanólica) após 4h de exposição à radiação UVC, sendo esta proteção mais acentuada nas nanocápsulas com ambos os polímeros e na nanoemulsão. A cinética de degradação do fármaco em todos os sistemas nanoestruturados estudados foi de primeira ordem, enquanto que para a solução etanólica de ubiquinona a reação de segunda ordem foi a que proporcionou o melhor ajuste. O estudo de estabilidade das formulações por 90 dias demonstrou que os sistemas foram instáveis quando armazenados a 40 ± 2ºC e UR 75 ± 5%, em especial a nanocápsula de Eudragit ®EPO. Entretanto, quando armazenados à temperatura ambiente, as formulações foram estáveis, conservando as características físico-químicas iniciais. Através de um teste de hemólise semi-quantitativo preliminar, foi demonstrada a compatibilidade das nanocápsulas de PCL com os eritrócitos humanos. Utilizando-se o método do MTT para avaliação da citotoxicidade, verificou-se que a ubiquinona livre e o óleo de pracaxi diminuíram o número de células viáveis das linhagens C6 e MCF-7, em comparação ao controle, sendo este potencial citotóxico ainda mais pronunciado quando se utilizou as nanocápsulas de PCL. Desta forma, os nanocarreadores desenvolvidos são sistemas promissores para a veiculação, estabilização e para se explorar as potencialidades terapêuticas da ubiquinona.

Dans cette étude nous avons utilisé le bisphénol A (BPA) comme polluant modèle pour analyser l’efficacité des différents processus de Fenton et photo-Fenton mis en place. Dans un premier temps nous avons étudié le processus de Fenton en présence du complexe Fe(III)-EDDS utilisé comme source de fer. Différents paramètres physico-chimiques (concentrations en H2O2, Fe(III)-EDDS, O2 et le pH) ont été testés afin d’optimiser l’efficacité du système en termes de dégradation du BPA. Parallèlement, le même type d’étude a été mené en présence de lumière (de 300 à 450 nm) afin d’étudier le processus de photo-Fenton. Dans les 2 cas nous avons mis en évidence un effet du pH peu commun puisque la dégradation de BPA est plus rapide et importante plus le pH est élevé dans une gamme allant de 3,0 à 9,0. Dans le but de comprendre le mécanisme mis en jeu des expériences d’inhibition de radicaux (·OH et HO2●/O2●-) ont été réalisées. Une des conclusions importantes de ce travail est que dans les deux systèmes le complexe Fe(III)-EDDS joue un rôle très positif pour la dégradation du BPA. De plus, nous avons également montré que ces processus étaient très efficaces pour des pH proches de la neutralité et faiblement basiques. La comparaison avec d’autres complexant du fer (EDTA, citrate, oxalate) montre qu’en présence du complexe Fe(III)-EDDS nous obtenons l’efficacité la plus importante. Ce résultat et le fait que les processus soient très efficaces à pH neutre ou faiblement basiques montrent que le complexe Fe(III)-EDDS est vraiment une source de fer très prometteuse dans les processus de Fenton et photo-Fenton. Dans une troisième partie nous avons regardé l’effet d’EDDS dans un système hétérogène en présence de Goethite comme source de fer. Dans ce chapitre il a été mis en évidence que l’EDDS inhibe le processus de Fenton, EDDS s’adsorbe fortement à la surface et limite la réactivité de H2O2 avec la surface de la Goethite. Par contre dans le processus de photo-Fenton, EDDS augmente l’efficacité de dégradation du BPA à pH proche de la neutralité et à faible concentration en H2O2. / In this study we used the bisphenol A (BPA) as a model pollutant to analyse the efficiency of the Fenton and photo-Fenton processes. In the first part of the thesis, we studied the Fenton process in the presence of the complex Fe(III)-EDDS used as iron source. Different physicochemical parameters (concentrations of H2O2, Fe(III)-EDDS, O2 and pH) were tested with the goal to optimized the efficiency of the system in terms of BPA degradation. In the same time, the same kind of experiments were performed in the presence of light (emission from 300 to 450 nm) to study the photo-Fenton process. In the two cases (Fenton and photo-Fenton), we observed a strong and not usual pH effect. Indeed, the degradation of BPA is faster and more important when the pH is higher in the range between 3.0 and 9.0. To understand the mechanisms involved in such processes, some inhibition experiments of radicals (·OH and HO2●/O2●-) were performed. One of the most important conclusion of this research work is that the Fe(III)-EDDS complex plays a very positive role for the degradation of BPA. Moreover, in the presence of Fe(III)-EDDS the Fenton and photo-Fenton processes are very efficient in neutral and slightly basic pH. The comparison with other iron complexes (EDTA,citrate, oxalate) shows that in the presence of Fe(III)-EDDS complex we obtained the better efficiency for the degradation of BPA. This result and the fact that Fe(III)-EDDS is efficient until pH 9.0 show that Fe(III)-EDDS complex is really a promising iron source for the Fenton and photo-Fenton processes. In a third part, we studied the effect of EDDS in a heterogeneous system in the presence of Goethite as an iron source. In this chapter, we demonstrated that the presence of EDDS is detrimental for the Fenton process and leads to an inhibition of the process. In fact, EDDS is strongly adsorbed at the surface of the Goethite and avoid the reactivity of H2O2 at the Goethite surface. On the contrary, in the photo-Fenton process EDDS increases the efficiency of the BPA degradation for pHs near 7.0 and at low H2O2 concentrations.

Orientador: Prof. Dr. José Antonio Souza / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, Santo André, 2018. / O objetivo deste trabalho e sintetizar materiais magneticos e semicondutores ocos micro/nanoestruturados hierarquicamente, para obter um melhor entendimento das propriedades fisicas e explorar aplicacoes tecnologicas. Inicialmente, microtubos de hematita e magnetita foram sintetizados por oxidacao termica juntamente com uma corrente eletrica aplicada e utilizando-se o microfio de ferro metalico como precursor. A fraccao volumetrica de Fe2O3(hematite) e Fe3O4(magnetite) nos microtubos e a formacao das nanoestruturas de hematite na superficie pode ser controlada por alteracoes sistematicas dos parametros de sintese tais como temperatura, rampa de aquecimento, tempo de aquecimento e valor da corrente electrica. A reacao quimica de oxidacao envolve um processo onde uma fina camada de oxido e formada primeiro na superficie do metal, seguida por difusao simultanea de ions metalicos atraves da camada oxida e difusao de oxigenio da atmosfera para o interior. A difusao para fora e mais rapida, levando a criacao de vacancias que coalescem em poros formando os microtubos. Medidas de resistividade eletrica in situ foram realizadas durante o processo de oxidacao mostrando todo o processo de formacao do microtubo. Imagens de microscopia eletronica de varredura mostram a morfologia do microtubo com diametro variando de 40 ¿Êm a 100 ¿Êm e comprimento de 5 mm. Medidas de difracao de raios-X em po evidenciam a presenca de fases cristalinas de hematita (Fe2O3) e magnetita (Fe3O4) nos microtubos. Nanoestruturas de hematita aparecem em forma de bastoes e fios dispersos homogeneamente ao redor da superficie do microtubo com diametros de 80-300 nm e comprimento de 1-5 ¿Êm. Experimentos in vitro envolvendo aderencia, migracao e proliferacao de culturas de celulas de fibroblastos na superficie dos microtubos indicaram a ausencia de citotoxicidade para este material. Tambem o calculo do torque e da forca magnetica desses microtubos com nanofios em funcao do gradiente de campo magnetico externo, mostrou que ele e robusto, abrindo a possibilidade para fabricacao de bio-microrobos magneticos para aplicacao em biotecnologia. Por outro lado, microarquiteturas ocas de SnS e ZnS decoradas com nanoestruturas foram sintetizadas por evaporacao termica livre de catalisadores utilizando microfios de metal e po de enxofre como materiais de partida. Para o SnS, observamos formacao de uma estrutura oca composta por uma camada metalica de Sn na superficie interna, e uma camada de SnS de estrutura ortorrombica com nanoestruturas de SnS na superficie. Para o ZnS, descobrimos a formacao de uma esfera oca com uma camada metalica na parte interna, uma camada de ZnS com fase cubica, e sobre ela nanoestruturas de ZnS com fase cristalina hexagonal cresceram homogeneamente. O diametro da microsfera e de 415 ¿Êm e os nanofios tem um diametro e comprimento medio de 70 nm e 7 ¿Êm, respectivamente. As microestruturas ocas semicondutoras de ZnS e SnS exibiram atividade eficiente para degradar azul de metileno sob irradiao com luz solar simulada. Os resultados revelam que essas nano/microestruturas possuem alta fotoatividade para degradacao organica. / The aim of this work is to synthesize hierarchically micro/nanostructured hollow magnetic and semiconductor materials, to obtain a better understanding on the physical properties, and find technological applications. Initially, hematite and magnetite microtubes were synthesized by thermal oxidation process along with the presence of an applied electrical current and using metallic iron microwire as a precursor. The volume fraction of both Fe2O3 (hematite) and Fe3O4 (magnetite) phase on microtubes can be controlled as well as surface nanostructures formation of hematite by systematic change of the synthesis parameters such as temperature, heating rate, annealing time and electrical current value. The oxidation chemical reaction involves a process where a thin oxide layer is formed first on the metal surface, followed by simultaneous outward diffusion of metal ions through the oxide scale and inward diffusion of oxygen from the atmosphere into the core. In our case, the outward diffusion is faster leading to the creation of vacancies which coalesce into voids forming the microtubes. In situ electrical resistivity measurements were carried out during the oxidation process showing the whole process of the microtube formation. Scanning electron microscopy images show microtube morphology with diameter ranging from 40 ìm to 100 ìm and length of 5 mm. X-ray powder diffraction measurements evidence the presence of hematite (Fe2O3) and magnetite (Fe3O4) crystal phases comprising microtubes. Nanostructures of hematite appear in form of sticks and wires homogeneously dispersed on the microtube surface with diameters ranking from 80 nm to 300 nm and length of 1 to 5 ìm. In vitro experiments involving adherence, migration, and proliferation of fibroblasts cell culture on the surface of the microtubes indicated the absence of immediate cytotoxicity for this material. We have also calculated both torque and driving magnetic force for these microtubes with nanowires as a function of external magnetic field gradient which were found to be robust opening the possibility for magnetic bio micro-robot device fabrication and application in biotechnology. On the other hand, SnS and ZnS hollow microarchitectures decorated with nanostructures were synthesized by catalysis free thermal evaporation technique using metal microwires and sulfur powder as starting materials. For SnS, we observed a hollow formation comprised of a thin metallic Sn layer in the inner surface, SnS orthorhombic structure thick layer with SnS nanostructures on the top. For ZnS, we found out the formation of hollow sphere with a thin metallic layer in the inner part, a thick cubic phase layer of ZnS, and on this second phase, nanostructures of ZnS hexagonal crystal phase grew up homogeneously. The microsphere diameter is about 415 ìm and the nanowires on the surface have average diameter of 70 nm and length 7 ìm. ZnS and SnS hollow semiconducting microstructures have exhibited efficient activity to degrade the methylene blue under simulated sunlight irradiation. The results reveal that these nano/microstructures have high photoactivity to organic degradation.

The subject of this thesis is the study of the degradation of polyurethanes in the weather conditions on the waste dumps and observation of the penetration of the potential degradation products into the environment.

M.Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Phenol, 2-chlorophenol (2-CP) is used in the manufacture of several chemical compounds including other chlorophenols, dyes, dentifrice and pesticides. The usage of these chemicals results in the discharge of 2-CP that is harmful to most biota in the environment. Therefore there is need to remove or degrade 2-CP from the environment, especially in water. This research focused on the synthesis, characterization and application of Ag doped semiconductor (TiO2, ZnO, and ZnS) nanoparticles for the removal of 2-CP from water. Sol-gel and co-precipitation methods were used to synthesize the nanoparticles with different Ag contents (1%, 3% and 5%). Silver metal was used as a doping agent due to its antibacterial activity and ability to improve the photocatalytic activity of the semiconductors for 2-CPdegradation under UV irradiation. Characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), Ultra-violet visible spectroscopy (UV-Vis) and photoluminescence spectra (PL) were used to characterize the structural, optical and physical properties of the nanoparticles, while Transmission electron microscopy (TEM) was used to characterize the surface of the nanoparticles. The XRD results confirmed the formation of anatase, wurtzite and blend phases of TiO2, ZnO and ZnS nanoparticles, respectively. The band gaps of the synthesized nanoparticles were 3.42 eV, 3.23 eV and 3.12 eV for TiO2, ZnO and ZnS nanoparticles respectively. The TEM images showed that all synthesized nanoparticles were uniform in shape. Photocatalytic degradation of 2-CP under UV irradiation confirmed that the semiconductor’s photocatalytic activities improved with the addition of Ag ions. The best removal percentage was obtained at doped Ag percentages of 5, 1 and 5 % using TiO2, ZnO and ZnS, respectively. In addition, the effects of various parameters affecting the photocatalytic degradation such as pH, initial concentrations of 2-CP and amount of catalyst (Ag doped TiO2, ZnO and ZnS, respectively) loading were examined and optimized. At the different initial concentrations of 2-CP, namely, 8, 20 and 50 ppm, the highest degradation efficiency was obtained at pH of 10.5 and 5 mg of catalyst dosage. However a decrease in initial concentration of 2-CP showed an increase in the photocatalytic efficiency. The degradation percentage of 2-CP obtained with Ag doped TiO2; ZnO and ZnS nanoparticles were 74.74, 57.8 and 45.49 %, respectively. Doping of these materials with Ag enhanced their photocatalytic activity; thus, they have the potential of degrading phenolic compounds, especially 2-chlorophenol, in water.

If a beer is exposed to visible light, it will become light-damaged over time, which is characterised by an undesirable odour and flavour of the drink. The confirmed cause of the above-mentioned flavour in beer is 3-methyl-2-buten-1-thiol (MBT). This substance is formed by non-enzymatic reactions in which riboflavin (vitamin B2) plays the role of photocatalyst and breaks down after transferring its excitation energy, charged by absorption of visible light. The loss of riboflavin results in a change in optical properties of the sample. The aim of this work is to investigate the possibilities of optical detection of light damage, through the analysis of riboflavin content, based on fluorescence and absorption of the sample. Since riboflavin is degraded when light damage occurs, it is possible to determine whether or not a sample is light damaged from its content in beer. Optical detection of light damage is non- invasive and can therefore determine the quality of the beer directly in the commercial bottle without the need to open it.

M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Electrospinning is a method that has gained more attention due to its capability in spinning a wide variety of polymeric fibers and nanoparticles embedded in polymer fibers. Polymer blending has been considered the most appropriate way for creating new materials with fused properties which improve poor chemical, mechanical, thermal and dynamic mechanical properties of each polymer. Hence, in this study, electrospinning technique was used to fabricate polyacrylonitrile (PAN) nanofibers at concentrations of (10, 12 and 14 wt%) and cellulose acetate (CA) nanofibers at concentrations of (14, 16 and 18 wt%). 10wt% of PAN and 16 wt% of CA were blended together and the optimum blend ratio was found to be 80/20 PAN/CA. TiO2 nanoparticles (0.2 and 0.4 wt%) were incorporated into CA nanofibers and (1, 2 and 3 wt%) were incorporated into PAN and PAN/CA blended polymers, respectively. Applied voltages of 20, 22 and 24 kV were varied at a spinning distance of 15cm and the optimum voltage for the fabrication of composite was 22 kV. The sol-gel method was used to synthesise the TiO2 nanoparticles at different calcination temperatures of 400, 500 and 600 ºC. The fabricated composite nanofibers were tested for antibacterial and photocatalytic activities. The synthesised nanomaterials were characterized using SEM, TEM, EDX, UV-Vis, PL, FTIR spectroscopy, XRD and TGA. The absorption and emission spectra illustrated the formation of TiO2 nanoparticles and the increase in absorption band edges. TEM showed the spherical morphology of the nanoparticles with average diameter of 12.2 nm for nanoparticles calcined at 500 ºC. SEM illustrated the diameter and morphology of the nanofibers and composites with the average diameter of 220, 338, 181, 250, 538, 294 nm for PAN, CA, PAN-TiO2, CA-TiO2, PAN/CA and PAN/CA-TiO2, respectively. XRD revealed anatase phase as the dominant crystalline phase of the synthesised nanoparticles. FTIR spectroscopy and EDX signified that the formation of composite nanofibers and the presence of TiO2 nanoparticles corresponded to the Ti-O stretching and Ti-O-Ti bands on the FTIR spectra. The antimicrobial activity of the composite nanofibers were tested against E. coli, S. aureus and C. albicans microorganisms. The photocatalytic activity of the nanomaterials was tested using methyl orange dye. PAN/CA-TiO2 composite nanofibers revealed the greatest antibacterial activity against selected microorganisms as compared to the other nanocomposites. PAN/CA-TiO2 nanocomposite (44%) showed greater rate of photodegradation of methyl orange than PAN-TiO2 nanofibers (28%) and TiO2 nanoparticles (12%) under visible light irradiation.

M. Tech. (Department of Chemistry, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Organic water pollutants such as dyes are difficult to biodegrade. In this study Fenton, photo-Fenton and photocatalysis were used to degrade methylene blue dye in the presence of copper oxide catalysts. The copper oxide catalysts were prepared with a precipitation reduction method. The effect of different preparation parameters on the catalyst properties and catalytic activity were investigated. The reducing agents, ascorbic acid (ASC, C6H8O6), hydrazine (N2H4), sodium boron hydride (NaBH4) and glucose (C₆H₁₂O₆) could be used to obtain the desired Cu2O phase. ASC, N2H4 and NaBH4 were able to reduce copper (II) to copper (I) at room temperature whereas glucose required a higher reduction temperature. Stoichiometric amounts of the reducing agents ASC, N2H4 and glucose and double the stoichiometric amount of NaBH4 were required to obtain Cu2O. A further increase in the amounts of NaBH4 and N2H4 resulted in the formation of copper metal (Cu (0)). High amounts of ASC did not over-reduce the copper. ASC also functioned as capping molecule and anti-oxidant preventing the oxidation of the Cu2O to CuO in air after preparation. Hydrazine was thus not able to protect the Cu2O against oxidation. The SEM results showed that an increase in the amount of the precipitating agent, NaOH, resulted in an increase in the particle sizes. The particle shapes changed from spherical to cubic when a high amount of NaOH was used with hydrazine as reducing agent. Smaller particle sizes were obtained when CuCl2 was used instead of CuSO4 and Cu(NO3)2. Larger crystallites formed when the preparation temperature was increased from room temperature to 100°C with glucose as reducing agent. TEM and XRD analyses showed that the micro-particles seen in SEM analyses are made up of nano-particles. The catalysts were not active for photocatalysis which may be explained by the oxidation of these nano-particles to form the photocatalytic inactive CuO. The catalysts were shown to be active for Fenton and photo-Fenton degradation. The addition of graphene and activated carbon to the Cu2O catalysts were detrimental to the catalytic activity. The percentage degradation of methylene blue by the Fenton reaction increased with an increase in the BET surface area from 1.5 m2/g to 10 m2/g and a further increase in the surface area resulted in a decrease in the percentage degradation. A direct correlation between the Fenton catalytic activity and the pore size were found which indicate that the reaction was mass transfer limited.

In der Entwicklung neuer Agrochemikalien ist es essentiell das weitere Schicksal im Bezug zum Abbau durch abiotische und biotische Einflüsse vorherzusagen. Pestizide gehören zu den Agrochemikalien und durch abiotischen und biotischen Stress werden Transformationsprodukte (TPs) gebildet. Daher ist es von Bedeutung, die TPs von Pestiziden und deren Entstehungsprozess zu untersuchen. Diese Dissertation beschäftigt sich mit biotischen und abiotischen Umwandlungsprozessen von zwei Modell-Pestiziden, nämlich Chlorpyrifos (ein Insektizid) und Fluopyram (ein Fungizid) unter Verwendung von Modellsystemen. Lebermikrosomeninkubation und elektrochemische Durchflusszellen, die an Online-Massenspektrometrie gekoppelt waren, wurden als experimenteller Modellansatz zu untersuchen um die Biotransformationsprozesse (phase I und phase II) der Ziel-Pestizide. Im zweiten Teil dieser Arbeit, wurden Photodegradationsprodukte der beiden Modellverbindungen durch Bestrahlung mit keimtötendem ultraviolettem Licht (200 - 280 nm) untersucht. Im letzten Teil dieser Arbeit wurde die Elektrochemie-Massenspektrometrie auf die Herstellung von Referenzstandards für Transformationsprodukte für das gezielte Screening in Lebensmittelproben ausgedehnt. Die strukturelle Aufklärung der Transformationsprodukte erfolgte mittels HPLC, gekoppelt an verschiedene Massenspektrometrietechniken (Single Quad, Triple Quad, FT-ICR HRMS, Triple TOF-MS, Orbitrap HRMS). Zusammenfassend konnte die Kopplung von EC/(LC)/MS als schnelle, zuverlässige, kostengünstige und matrix-unabhängige Methode genutzt werden, um den oxidativen Phase-I und II Metabolismus von Fluopyram und Chlorpyrifos zu simulieren. EC/MS könnte weiterhin zur Synthese von TP Referenzstandards und zur Messung von Realproben genutzt werden. Neue TPs und deren Bildungsmechanismen konnten im Rahmen dieser Dissertation für beide untersuchten Substanzen identifiziert werden. / One of the crucial steps of developing a new agrochemical product is predicting its fate following biotic or abiotic stress. In this regard, pesticides undergo transformation processes in response to biotic and abiotic stress. Therefore, it is important to investigate pesticides’ transformation products (TPs) and the formation processes they undergo. This dissertation deals on biotic and abiotic transformation processes of two model pesticides namely chlorpyrifos (an insecticide) and fluopyram (a fungicide) using model systems. Liver microsome incubation and electrochemical-flow-through cell coupled to online mass spectrometry were used as a model experimental approach to investigate phase I and phase II biotransformation processes of the targeted pesticides. In the second part of this thesis, photodegradation products of the two model compounds were investigated by irradiating with germicidal ultraviolet light (200 – 280 nm). In the last part of this work, electrochemistry-mass spectrometry was scaled-up to the production of transformation product reference standards for targeted screening in different food samples. Structural elucidations of transformation products were performed using HPLC coupled to different mass spectrometry techniques (single quad, triple quad, FT-ICR HRMS, TripleTOF-MS, Orbitrap HRMS). In summary, a fast, reliable, cost-effective and matrix-free simulation of oxidative metabolism (phase I and II) of fluopyram and chlorpyrifos was achieved here by EC/(LC)/MS. EC/MS could, therefore, be scaled up to synthesis TP reference standards for real sample investigation. Additionally, new TPs and their mechanisms were identified for both investigated compounds.

No description available.