Organic aerosol is a major constituent of atmospheric fine particulates (PM2.5), which adversely affect human health and change the Earth’s radiative energy balance. Primary organic aerosol is directly emitted from sources and secondary organic aerosol (SOA) is formed in the atmosphere following oxidation of volatile organic compounds (VOC) from anthropogenic and biogenic sources. Biogenic SOA is enhanced by anthropogenic pollutants such as sulfate and NOx that mainly come from fossil fuel combustion. However, the extent to which the anthropogenic pollutants enhance biogenic SOA in different environments is unknown. The central hypothesis of this thesis is that organosulfates, organic compounds containing a sulfate ester group, are useful as tracers for anthropogenically-influenced biogenic SOA. This research aims to provide a better understanding of the sources of PM2.5 organic carbon (OC), particularly secondary organic carbon (SOC), through the inclusion of organosulfates in an organic tracer-based source apportionment model. The specific objectives of this research include 1) development of a highly sensitive and accurate method to quantify highly polar organosulfates in atmospheric aerosols, 2) identification and quantification of major organosulfate species in the ambient air, and 3) determination of anthropogenic and biogenic sources and their contributions to PM2.5 OC using an organic tracer-based positive matrix factorization (PMF) model. A highly sensitive and accurate method was developed and validated for the quantification of highly polar organosulfates using hydrophilic interaction liquid chromatography (HILIC) and tandem mass spectrometry (MS/MS). The developed method shows excellent retention of carboxylic acid and hydroxyl containing organosulfates. The HILIC-MS/MS method was applied to PM2.5 samples collected in summer 2013 at a rural site in Centreville, AL. Quantified organosulfates accounted for approximately 0.3% of PM2.5 OC. Other major organosulfates, for which standards are not available, were monitored by their fragmentation to the bisulfate anion and/ or sulfate ion radical. The major organosulfates were determined to be 2-methyltetrol sulfate and other isoprene-derived organosulfates. Eight sources of the PM2.5 OC in Centreville, AL were identified using PMF model through the application of organosulfates and commonly used organic tracers measured in samples collected during the daytime and nighttime: vehicle emissions (8%), prescribed burning (11%), isoprene SOC formed under low-NOx (13%) and high-NOx conditions (11%), SOC formed by photochemical reactions (9%), oxidatively aged biogenic SOC (6%), sulfuric acid-influenced SOC (21%), and monoterpene SOC formed under high-NOx conditions (21%). The organosulfates enabled organic tracer-based PMF to resolve sulfuric acid-influenced SOC, while the daytime and nighttime measurements enabled organic tracer-based PMF to resolve SOC formation pathways with diurnal variations (e.g. SOC formed by photochemical reactions). The PM2.5 OC in Centreville was mainly secondary in origin (81%) and was influenced by NOx, ozone (a product of photochemical reactions of NOx and VOC), and sulfuric acid. Together, primary and secondary OC influenced by the fossil fuel use was 76%. Thus, the majority of the PM2.5 OC in Centreville during summer can be controlled by the reduction of fossil fuel use. The HILIC-MS/MS method was also applied to daily PM2.5 samples collected from an urban site in Atlanta, GA during August 2015. The major organosulfate species identified in Atlanta were dominated by 2-methyltetrol sulfate and other isoprene-derived organosulfates, similar to Centreville. They contributed 16% of PM2.5 OC and accounted for the majority of the isoprene-derived SOA that had not previously been identified at the molecular level. The concentrations of the major isoprene-derived organosulfates in Atlanta were two to six times higher than in Centreville. The greatest enhancement was obtained for 2-methylglyceric acid sulfate, a known isoprene SOA tracer formed under high-NOx conditions, reflecting the 15 times higher average NOx concentration in Atlanta during August 2015 compared to Centreville in summer 2013. These results indicate that NOx had a stronger influence on isoprene-derived organosulfate formation in urban Atlanta compared to rural Centreville. Overall, these results indicate that organosulfates are useful tracers for anthropogenically-influenced biogenic SOA. Thus, it is important to quantify them for use in organic tracer-based PMF modeling to determine the anthropogenically-influenced biogenic SOC in PM2.5 OC.

Les ions métalliques (Fe, Zn, Cu, Mn, Ni, Co, Mo…) jouent un rôle vital dans un grand nombre de processus biologiques. Leur carence et leur excès entraînent des défauts de croissance voire la mort. Pour survivre et croître, certaines bactéries ont développé des stratégies pour acquérir les métaux dans leur environnement basées sur la synthèse de ligands complexant les métaux. Les plantes, elles, stockent les métaux et les transportent entre les tissus sous des formes chimiques particulières et un rôle grandissant pour les petits complexes métalliques semble se révéler. La spéciation des métaux gouvernerait donc leur biodisponibilité pour les consommateurs en ce qui concerne les plantes comestibles. Cette thèse a pour but le développement de méthodes analytiques pour l’identification et la quantification des formes chimiques des métaux chez les bactéries et les plantes.Les techniques de séparation chromatographique, comme la chromatographie d’exclusion stérique (SEC) et la chromatographie d’interaction hydrophile (HILIC), furent couplées à la spectrométrie de masse (MS) avec une ionisation préalable par plasma induit (ICP MS) ou par électrospray pour une détection élémentaire et moléculaire respectivement. La méthodologie analytique développée ici, qui est basée sur l’utilisation de l’HILIC avec détection double par ICP MS et électrospray MS, s’est avérée cruciale pour la découverte et la caractérisation de deux nouveaux métallophores, la staphylopine chez Staphylococcus aureus et la pseudopaline chez Pseudomonas aeruginosa. Ces métallophores sont synthétisés et exportés par les bactéries et servent pour l’acquisition des métaux de transition divalents dans les milieux très pauvres en métaux grâce à leur pouvoir complexant.Des techniques dédiées de préparation d’échantillons, incluant le fractionnement des extraits solubles à l’eau, furent mises en place pour l’analyse du fer dans le maïs. Les approches instrumentales développées, notamment après le fractionnement du fer l’échantillon, permirent l’identification par spectrométrie de masse de complexes du fer avec le citrate, le muginéate et le phytate dans les grains de maïs. Il existe aussi une différence significative dans les concentrations de certaines polyamines entre certaines variétés de graines contenant du fer faiblement biodisponible et celles contenant du fer fortement biodisponible. La plus grande abondance de complexe fer-muginéate dans les extraits gastro-intestinaux des variétés à fer fortement biodisponible semblerait indiqué un rôle important pour ce complexe dans la biodisponibilité du fer. Finalement, des ratios molaires plus faibles entre le phytate extrait et le fer qui lui est associé sembleraient aussi être un des facteurs lié à une plus grande biodisponibilité du fer. / Metal (Fe, Zn, Cu, Mn, Ni, Co, Mo…) ions play a vital role in a large number of biological processes. Both their deficiency and excess will lead to severe growth impairment or death. In order to survive and to grow, bacteria developed strategies to acquire metals from the environment based on the synthesis of metal complexing ligands. Plants store metals and transport them between tissues in particular chemical forms and a rising role for small metal complexes seems to be revealed. Therefore their speciation governs the bioavailability of the metals to consumers in the case of edible plants. This thesis aims at the development of analytical methods for the identification and quantification of metal chemical forms in bacteria and in plants.Chromatographic separation techniques, such as size exclusion chromatography (SEC) and hydrophilic interaction chromatography (HILIC) were coupled to mass spectrometry (MS) using ionization in an inductively coupled plasma (ICP MS) or electrospray for elemental and molecular detection, respectively. The developed analytical methodology based on HILIC with dual ICP MS and electrospray MS detection turned out to be crucial for the discovery and characterization of two novels metallophores, staphylopine in Staphylococcus aureus and pseudopaline in Pseudomonas aeruginosa. These metallophores are synthesized and exported by the bacteria and serve for the uptake of divalent transition metal in metal scarce conditions by means of chelation. Dedicated samples preparation techniques, including fractionation of water soluble extracts, were developed for iron analyses in maize. The developed instrumental approaches following the iron fractionation methods allowed the identification by mass spectrometry of citrate, mugineate and phytate complexes with iron in maize kernels. There was also a significant difference in some polyamine concentrations observed between some kernels with low and high bioavailable iron. The higher abundance of the iron-mugineate complex in the gastrointestinal extract in high bioavailable maize variety possibly indicates that iron-mugineate would have an important role in iron biodisponibility. Finally, lower molar ratios between extracted phytate and iron associated to it would seem to be also a key aspect for higher iron bioavailability.

Em uma sociedade que lida com pressão diariamente para completar suas tarefas, a privação de sono é uma consequência comum. Como artifício para manter-se apto a trabalhar ou se divertir à noite, algumas pessoas utilizam a cocaína, cujo consumo é estudado há décadas, mas cuja associação com a privação de sono ainda não foi avaliada pela toxicologia. Este estudo utiliza a metabolômica para gerar um mapa de alterações metabólicas associadas a estas condições e sua iteração. Utilizando análise cromatográfica líquida no modo HILIC e espectrometria de massas com um analisador do tipo \"tempo de voo\" (TOF), os cromatogramas e espectros urinários de 60 ratos Wistar machos foram analisados utilizando o pacote XCMS (Bioconductor) na plataforma R. Os tratamentos estatísticos de dados (PCA, OPLS-DA, MANOVA) foram realizados através dos programas SIMCA 11 P+ e IBM SPSS, culminando em atribuições putativas dos metabólitos discriminantes nas condições estudadas (efeito da cocaína, efeito da privação total de sono e seu efeito combinado). Foram então evidenciados cinco marcadores biológicos de dano associados à cocaína, três associados à privação de sono e dois à sua iteração. Estes metabólitos foram identificados putativamente através de busca em banco de dados (Metlin, MassTrix, HMDB, Lipidmaps) e tiveram suas rotas metabólicas associadas através do banco de rotas metabólicas KEGG. Há diferenças metabólicas estatisticamente evidenciáveis e inclusive duradouras nas vias do ciclo da tirosina e do sistema dopaminérgico, além do ciclo do citrato. / In a society that deals daily with pressure to complete its tasks, sleep deprivation is a common consequence. As an excuse to keep oneself fit to work but to have fun at night some people use cocaine, whose consumption is studied for decades, but the association with sleep deprivation had not yet been evaluated by toxicology. This study uses metabolomics to generate a map of metabolic abnormalities associated with these conditions and its iteration. Using liquid chromatographic in HILIC mode and \"time of flight\" mass spectrometry (TOF), mass chromatograms of urine from 60 male Wistar rats were analysed using XCMS package (Bioconductor) running on R platform. Statistical data treatment (PCA, OPLS-DA, MANOVA) were performed using the programs SIMCA P + 11 and IBM SPSS, culminating in putative metabolites assignments that discriminate the conditions in the study (cocaine effect, total sleep deprivation effect and their combined effect). We highlighted five biological markers of damage associated with cocaine, three associated with sleep deprivation and their iteration. These metabolites were putatively identified by public databases (Metlin, MassTrix, HMDB, Lipidmaps) and their associated metabolic pathways were assessed through KEGG database. There are significant differences on metabolic pathways of the tyrosine cycle, the dopaminergic system and the citrate cycle.

Em uma sociedade que lida com pressão diariamente para completar suas tarefas, a privação de sono é uma consequência comum. Como artifício para manter-se apto a trabalhar ou se divertir à noite, algumas pessoas utilizam a cocaína, cujo consumo é estudado há décadas, mas cuja associação com a privação de sono ainda não foi avaliada pela toxicologia. Este estudo utiliza a metabolômica para gerar um mapa de alterações metabólicas associadas a estas condições e sua iteração. Utilizando análise cromatográfica líquida no modo HILIC e espectrometria de massas com um analisador do tipo \"tempo de voo\" (TOF), os cromatogramas e espectros urinários de 60 ratos Wistar machos foram analisados utilizando o pacote XCMS (Bioconductor) na plataforma R. Os tratamentos estatísticos de dados (PCA, OPLS-DA, MANOVA) foram realizados através dos programas SIMCA 11 P+ e IBM SPSS, culminando em atribuições putativas dos metabólitos discriminantes nas condições estudadas (efeito da cocaína, efeito da privação total de sono e seu efeito combinado). Foram então evidenciados cinco marcadores biológicos de dano associados à cocaína, três associados à privação de sono e dois à sua iteração. Estes metabólitos foram identificados putativamente através de busca em banco de dados (Metlin, MassTrix, HMDB, Lipidmaps) e tiveram suas rotas metabólicas associadas através do banco de rotas metabólicas KEGG. Há diferenças metabólicas estatisticamente evidenciáveis e inclusive duradouras nas vias do ciclo da tirosina e do sistema dopaminérgico, além do ciclo do citrato. / In a society that deals daily with pressure to complete its tasks, sleep deprivation is a common consequence. As an excuse to keep oneself fit to work but to have fun at night some people use cocaine, whose consumption is studied for decades, but the association with sleep deprivation had not yet been evaluated by toxicology. This study uses metabolomics to generate a map of metabolic abnormalities associated with these conditions and its iteration. Using liquid chromatographic in HILIC mode and \"time of flight\" mass spectrometry (TOF), mass chromatograms of urine from 60 male Wistar rats were analysed using XCMS package (Bioconductor) running on R platform. Statistical data treatment (PCA, OPLS-DA, MANOVA) were performed using the programs SIMCA P + 11 and IBM SPSS, culminating in putative metabolites assignments that discriminate the conditions in the study (cocaine effect, total sleep deprivation effect and their combined effect). We highlighted five biological markers of damage associated with cocaine, three associated with sleep deprivation and their iteration. These metabolites were putatively identified by public databases (Metlin, MassTrix, HMDB, Lipidmaps) and their associated metabolic pathways were assessed through KEGG database. There are significant differences on metabolic pathways of the tyrosine cycle, the dopaminergic system and the citrate cycle.