Soil organic matter (SOM) plays an important role in the global carbon cycle. Therefore, it is important to understand the stability of SOM, which is related to several processes. Its intrinsic properties may be related to its stability, for example black carbon is considered to be relatively resistant to degradation. In most soils, the dark horizons coincide with the superficial layers or horizons due to the greater accumulation of organic matter, but in the southern states of Brazil, the presence of soils with dark subsurface horizons is frequently observed. The dark subsurface horizon of these soils are similar to a sombric horizon. Aspects about its origin, formation and preservation have not yet been fully elucidated. The objective of this work is to understand the formation of \'sombric\' horizons in soils of the region from Tijucas do Sul (Paraná, Brazil). Five soil profiles were described and collected, from which three originate from a toposequence and contained a \'sombric\' horizon (P1-P3), a reference soil that is representative of the area (P5) and an intermediate soil (P4) that showed morphology between the reference soil and the soils with a \'sombric\' horizon. To this end SOM is studied for its molecular composition by the pyrolysis technique coupled to gas chromatography and mass spectrometry (pyrolysis-GC-MS). In addition, 13C isotopic composition (δ13C) and phytolytic composition were studied in order to understand paleoclimatic conditions. These results will be related to past environmental conditions using 14C dating techniques, and supported by classical soil analysis. The samples of the horizons were submitted to the SOM chemical fractionation, generating two fractions: extractable fraction with NaOH (EXT) and residue (RES). The morphology of the profiles showed an intense biological activity in A horizons and a wide distribution of microfragments of charcoals. The lateral continuity of \'sombric\' horizons in toposequence soils was also observed, which differentiated them (P1-P3) from buried A horizons. The distribution of SOM in the fractions studied was the same for the five profiles studied: EXT> RES. Products related to wildfires such as polyaromatics (PAHs; BC) were found in all profiles, but in greater relative abundance in the \'sombric\' horizons, indicating a higher incidence of fire during the formation of these horizons and these compounds can be related to the maintenance of dark color of the \'sombric\' horizons. In relation to the paleoclimatic conditions it was observed that the dark subsurface horizons were developed during the Mid-Holocene under vegetation composed mainly by C4 grasses with shrubs, evidencing a drier climate corresponding to a higher fire incidence. / A matéria orgânica do solo (MOS) desempenha um papel importante no ciclo global do carbono. Portanto, é importante entender a estabilidade da MOS, que está relacionada a vários processos. As suas propriedades intrínsecas podem estar relacionadas com a sua estabilidade, por exemplo, o \"black carbon\" é considerado relativamente resistente à degradação. Na maioria dos solos, os horizontes escuros coincidem com as camadas ou horizontes superficiais devido ao maior acúmulo de matéria orgânica, mas nos estados do sul do Brasil, a presença de solos com horizontes subsuperficiais escurecidos é frequentemente observada. O horizonte subsuperficial escurecido destes solos assemelha-se a um horizonte sômbrico. Aspectos sobre sua origem, formação e preservação ainda não foram totalmente elucidados. O objetivo deste trabalho é compreender a formação de horizontes \'sômbricos\' em solos da região de Tijucas do Sul (Paraná, Brasil). Foram descritos e coletados cinco perfis de solo, dos quais três estão localizados em uma topossequência e continham um horizonte similar ao sômbrico (P1-P3), um solo de referência representativo da área (P5) e um solo intermediário (P4) que apresentou uma morfologia entre o solo de referência e os solos com horizonte \'sômbrico\'. Para este fim, a MOS foi estudada pela sua composição molecular através da técnica de pirólise acoplada à cromatografia gasosa e espectrometria de massa (pirólise-GC-MS). Além disso, estudou-se a composição isotópica 13C (δ 13C) e a composição fitolítica, a fim de compreender as condições paleoclimáticas que foram relacionados com as condições ambientais passadas usando técnicas de datação com 14C, e suportados pelas análises clássicas de solo. As amostras dos horizontes foram submetidas ao fracionamento químico MOS, gerando duas frações: fração extraível com NaOH (EXT) e resíduo (RES). A morfologia dos perfis mostrou uma intensa atividade biológica nos horizontes A e uma ampla distribuição de microfragmentos de carvão. Observouse também a continuidade lateral de horizontes \'sômbricos\' em solos da topossequência (P1-P3), diferenciando-os dos horizontes A enterrados. A distribuição da MOS nas frações estudadas pela pirólise foi a mesma para os cinco perfis: EXT> RES. Os produtos relacionados a incêndios florestais como os poliaromáticos (PAHs, BC) foram encontrados em todos os perfis, mas em maior abundância relativa nos horizontes sômbricos, indicando uma maior incidência de incêndio durante a formação destes horizontes. Os PAHs podem estar relacionados com a manutenção da cor escura dos horizontes \'sômbricos\'. Em relação às condições paleoclimáticas observou-se que os horizontes subsuperficiais escurecidos foram desenvolvidos durante o Holoceno Médio sob vegetação composta principalmente por gramíneas C4 com arbustos, evidenciando um clima mais seco correspondente a maior incidência de incêndio.

<p>This thesis is based on studies in which the suitability of various gas chromatography (GC) injection techniques was examined for the determination of polybrominated diphenyl ethers (PBDEs) and carbazoles, two groups of compounds that are thermally labile and/or have high boiling-points. For such substances, it is essential to introduce the samples into the GC system in an appropriate way to avoid degradation and other potential problems. In addition, different types of gas chromatographic column system and mass spectrometric detectors were evaluated for the determination of PBDEs.</p><p>Conventional injectors, such as splitless, on-column and programmed temperature vaporizing (PTV) injectors were evaluated and optimized for determination of PBDEs. The results show on-column injection to be the best option, providing low discrimination and high precision. The splitless injector is commonly used for “dirty” samples. However, it is not suitable for determination of the high molecular weight congeners, since it tends to discriminate against them and promote their degradation, leading to poor precision and accuracy. The PTV injector appears to be a more suitable alternative. The use of liners reduces problems associated with potential interferents such as polar compounds and lipids and compared to the hot splitless injector, it provides gentler solvent evaporation, due to its temperature programming feature, leading to low discrimination and variance.</p><p>Increasing the injection volume from the conventional 1-3 µL to >50 µL offers two main benefits. Firstly, the overall detection and quantification limits are decreased, since the entire sample extract can be injected into the GC system. Secondly, large volume injections enable hyphenation of preceding techniques such as liquid chromatography (LC), solid phase extraction and other kinds of extraction. Large-volume injections were utilized and optimized in the studies included in this thesis.</p><p>With a loop-type injector/interface large sample volumes can be injected on-column providing low risk of discrimination against compounds with low volatility. This injector was used for the determination of PBDEs in air and as an interface for the determination of carbazoles by LC-GC. Peak distortion is a frequently encountered problem associated with this type of injector that was addressed and solved during the work underlying this thesis.</p><p>The PTV can be used as a large volume injector, in so-called solvent vent mode. This technique was evaluated for the determination of PBDEs and as an interface for coupling dynamic sonication-assisted solvent extraction online to GC. The results show that careful optimization of the injection parameters is required, but also that the PTV is robust and yields reproducible results.</p><p>PBDEs are commonly detected using mass spectrometry in electron capture negative ionization (ECNI) mode, monitoring bromine ions (m/z 79 and 81). The mass spectrometric properties of the fully brominated diphenyl ether, BDE-209, have been investigated. A high molecular weight fragment at m/z 486/488 enables the use of 13C-labeled BDE-209 as an internal surrogate standard.</p>

English: Semiochemicals informative molecules used in insect-insect or plant-insect interactions have been widely considered within various integrated pest management (IPM) strategies. In the present thesis, two sesquiterpenoids, E-β-farnesene and E-β-caryophyllene, were formulated for their related properties as aphid enemy attractants. E-β-farnesene, the alarm pheromone of many aphid species, was also identified as a kairomone by attracting and inducing oviposition of aphid predators (Episyrphus balteatus De Geer (Diptera: Syrphidae)) and by attracting aphid parasitoids (Aphidius ervi Haliday (Hymenoptera: Braconidae)). E-β-caryophyllene was identified as a potential component of the aggregation pheromone of the Asian ladybird, Harmonia axyridis Pallas, another aphid predator. The two products were purified from essential oils of Matricaria chamomilla L. (Asteraceae) and Nepeta cataria L. (Lamiaceae) for E-β-farnesene and E-β-caryophyllene, respectively. Natural and biodegradable slow-release formulations were then investigated in order to deliver these molecules on crop fields for a long period of time as biological control devices. Due to their sensitivity to oxidation, both sesquiterpenes needed to be protected from oxygen degradation. For this purpose, alginate hydrophilic matrix with low oxygen permeability was used as polymer for the formulations: the main objective was to deliver semiochemical substances in the air in a controlled way. Consequently, a careful selection of alginates was realised. Formulated beads showed different structural and encapsulation properties depending on various formulation factors. Alginate formulations were characterized by texturometry and by confocal microscopy in order to observe the distribution of semiochemicals in alginate network. The last step of alginate bead characterisation consisted in studying release rate of semiochemicals in laboratory-controlled conditions by optimised trapping and validated Fast-GC procedures. Finally, the efficiency of formulations as aphid predator (Syrphidae) and parasitoids (A. ervi) attractants was demonstrated by field trapping and olfactometry experiments. Français: Les sémiochimiques molécules véhiculant des informations au sein des interactions insecte-insecte ou plante-insecte ont été largement utilisés dans de nombreuses stratégies de lutte intégrée. La présente thèse de doctorat décrit la formulation de deux sesquiterpènes, le E-β-farnésène et le E-β-caryophyllène, pour leurs propriétés relatées dans la littérature en tant quattractants des ennemis des pucerons. En effet, le E-β-farnésène, la phéromone dalarme de nombreuses espèces de pucerons, a également été identifié comme kairomone en attirant des parasitoïdes (Aphidius ervi Haliday (Hymenoptera: Braconidae)) et des prédateurs de pucerons (Episyrphus balteatus De Geer (Diptera: Syrphidae)) et en induisant un comportement doviposition chez ces derniers. Le E-β-caryophyllène a récemment été identifié comme un composé probable de la phéromone dagrégation des coccinelles asiatiques, Harmonia axyridis Pallas, également prédatrices de pucerons. Les deux produits ont été purifiés au départ des huiles essentielles de Matricaria chamomilla L. (Asteraceae) et de Nepeta cataria L. (Lamiaceae) respectivement dans le cas du E-β-farnésène et du E-β-caryophyllène. Des formulations biodégradables et dorigine naturelle ont ensuite été développées comme outil de contrôle biologique afin de libérer les deux composés de façon progressive. En raison de leur sensibilité à loxydation, ces deux sesquiterpènes devaient être protégés de loxygène. A cette fin, de lalginate matrice hydrophile offrant une faible perméabilité à loxygène a été utilisé comme polymère de formulation : le principal objectif était de délivrer les substances sémiochimiques dans lair dune façon contrôlée. En conséquence, lalginate a été sélectionné de façon minutieuse. Les billes formulées ont montrés des propriétés structurelles et dencapsulation différentes en fonction de nombreux facteurs intervenant lors de la formulation. Les formulations ont été caractérisées par texturométrie et par microscopie confocale de façon à observer la distribution des sémiochimiques au sein du réseau dalginate. La dernière étape de caractérisation des billes a consisté en létude du taux de libération des sémiochimiques dans des conditions contrôlées de laboratoire après avoir optimisé la technique de piégeage des volatils et validé la procédure danalyse par GC rapide. Finalement, lefficacité dattraction des formulations envers les prédateurs et les parasitoïdes de pucerons a été démontrée par des expériences de piégeage sur cultures et des essais dolfactométrie.

From its first use in the field of biochemistry, instrumental analysis offered a variety of invaluable tools for the comprehensive description of biological systems. Multi-selective methods that aim to cover as many endogenous compounds as possible in biological samples use different analytical platforms and include methods like gene expression profile and metabolite profile analysis. The enormous amount of data generated in application of profiling methods needs to be evaluated in a manner appropriate to the question under investigation. The new field of system biology rises to the challenge to develop strategies for collecting, processing, interpreting, and archiving this vast amount of data; to make those data available in form of databases, tools, models, and networks to the scientific community.<br><br> On the background of this development a multi-selective method for the determination of phytohormones was developed and optimised, complementing the profile analyses which are already in use (Chapter I). The general feasibility of a simultaneous analysis of plant metabolites and phytohormones in one sample set-up was tested by studies on the analytical robustness of the metabolite profiling protocol. The recovery of plant metabolites proved to be satisfactory robust against variations in the extraction protocol by using common extraction procedures for phytohormones; a joint extraction of metabolites and hormones from plant tissue seems practicable (Chapter II).<br><br> Quantification of compounds within the context of profiling methods requires particular scrutiny (Chapter II). In Chapter III, the potential of stable-isotope in vivo labelling as normalisation strategy for profiling data acquired with mass spectrometry is discussed. First promising results were obtained for a reproducible quantification by stable-isotope in vivo labelling, which was applied in metabolomic studies.<br><br> In-parallel application of metabolite and phytohormone analysis to seedlings of the model plant Arabidopsis thaliana exposed to sulfate limitation was used to investigate the relationship between the endogenous concentration of signal elements and the ‘metabolic phenotype’ of a plant. An automated evaluation strategy was developed to process data of compounds with diverse physiological nature, such as signal elements, genes and metabolites – all which act in vivo in a conditional, time-resolved manner (Chapter IV). Final data analysis focussed on conditionality of signal-metabolome interactions. / Die instrumentelle Analytik stellt mit ihrem unschätzbaren Methodenreichtum Analysenwerkzeuge zur Verfügung, die seit ihrem Einzug in die Biologie die Aufzeichnung immer komplexerer ‚Momentaufnahmen’ von biologischen Systemen ermöglichen. Konkret hervorzuheben sind dabei vor allem die sogenannten ‚Profilmethoden’. Die Anwendung von Profilmethoden zielt darauf ab, aus einer bestimmten Stoffklasse so viele zugehörige Komponenten wie nur möglich gleichzeitig zu erfassen. <br><br> Für die Auswertung derart komplexer Daten müssen nun auch entsprechende Auswertungsmethoden bereit gestellt werden. Das neu entstandene Fachgebiet der Systembiologie erarbeitet deshalb Strategien zum Sammeln, Auswerten und Archivieren komplexer Daten, um dieses gesammelte Wissen in Form von Datenbanken, Modellen und Netzwerken der allgemeinen Nutzung zugänglich zu machen.<br><br> Vor diesem Hintergrund wurde den vorhandenen Profilanalysen eine Methode zur Erfassung von Pflanzenhormonen hinzugefügt. Verschiedene Experimente bestätigten die Möglichkeit zur Kopplung von Pflanzenhormon- und Pflanzeninhaltsstoff(=metabolit)-Profilanalyse. In weiteren Untersuchungen wurde das Potential einer innovativen Standardisierungstechnologie für die mengenmässige Erfassung von Pflanzeninhaltsstoffen in biologischen Proben betrachtet (in vivo labelling mit stabilen Isotopen).<br><br> Hormon- und Metabolitprofilanalyse wurden dann parallel angewandt, um Wechselwirkungen zwischen der Konzentration von Signalkomponenten und der Ausprägung des Stoffwechsels in Keimlingen der Modellpflanze Arabidopsis thaliana zu untersuchen. Es wurde eine Prozessierungsmethode entwickelt, die es auf einfache Art und Weise erlaubt, Daten oder Komponenten verschiedenen Ursprungs wie Signalelemente, Gene und Metabolite, die in biologischen Systemen zeitlich versetzt aktiv oder verändert erscheinen, im Zusammenhang zu betrachten. Die abschließende Analyse aller Daten richtet sich auf die Abschätzung der Bedingtheit von Signal-Metabolismus Interaktionen.

The advent of large-scale and high-throughput technologies has recently caused a shift in focus in contemporary biology from decades of reductionism towards a more systemic view. Alongside the availability of genome sequences the exploration of organisms utilizing such approach should give rise to a more comprehensive understanding of complex systems. Domestication and intensive breeding of crop plants has led to a parallel narrowing of their genetic basis. The potential to improve crops by conventional breeding using elite cultivars is therefore rather limited and molecular technologies, such as marker assisted selection (MAS) are currently being exploited to re-introduce allelic variance from wild species. Molecular breeding strategies have mostly focused on the introduction of yield or resistance related traits to date. However given that medical research has highlighted the importance of crop compositional quality in the human diet this research field is rapidly becoming more important. Chemical composition of biological tissues can be efficiently assessed by metabolite profiling techniques, which allow the multivariate detection of metabolites of a given biological sample.<br><br> Here, a GC/MS metabolite profiling approach has been applied to investigate natural variation of tomatoes with respect to the chemical composition of their fruits. The establishment of a mass spectral and retention index (MSRI) library was a prerequisite for this work in order to establish a framework for the identification of metabolites from a complex mixture. As mass spectral and retention index information is highly important for the metabolomics community this library was made publicly available. Metabolite profiling of tomato wild species revealed large differences in the chemical composition, especially of amino and organic acids, as well as on the sugar composition and secondary metabolites. Intriguingly, the analysis of a set of <i>S. pennellii</i> introgression lines (IL) identified 889 quantitative trait loci of compositional quality and 326 yield-associated traits. These traits are characterized by increases/decreases not only of single metabolites but also of entire metabolic pathways, thus highlighting the potential of this approach in uncovering novel aspects of metabolic regulation. Finally the biosynthetic pathway of the phenylalanine-derived fruit volatiles phenylethanol and phenylacetaldehyde was elucidated via a combination of metabolic profiling of natural variation, stable isotope tracer experiments and reverse genetic experimentation. / Die Einführung von Hochdurchsatzmethoden zur Analyse von biologischen Systemen, sowie die umfangreiche Sequenzierung von Genomen haben zu einer Verlagerung der Forschung „im Detail“ zu einer ganzheitlicheren Betrachtungsweise auf Systemebene geführt. Aus einer jahrhundertlangen, intensiven Züchtung und Selektion von Nutzpflanzen resultierte gleichzeitig eine Abnahme der genetischen Varianz. Daraus resultierend sind Nutzpflanzen anfälliger gegenüber Stressfaktoren, wie Pathogenen, hohen Salzkonzentrationen oder Trockenheit, als ihre Wildarten. Das Potential konventioneller Züchtung scheint somit heute an seine Grenzen gekommen zu sein. Daher versucht man mittels moderner Molekulartechnik, wie zum Beispiel Marker-gestützte Selektion, Gene oder ganze Genombereiche von Wildarten mit hoher genetischer Variation in Nutzpflanzen einzukreuzen, vornehmlich mit dem Ziel einer Ertrags- bzw. Resistenzsteigerung. Neueste medizinische Studien belegen, dass die Ernährung eine wesentliche Rolle für die menschliche Gesundheit spielt. Besonders wichtig sind hierbei die gesundheitsfördernden Substanzen in pflanzlichen Nahrungsmitteln. Aus diesem Grund kommt der Erforschung der biochemischen Zusammensetzung von biologischen Proben eine immer größere Bedeutung zu. Diese Untersuchung kann elegant durch Metabolitenprofile, welche die multivariate Analyse komplexer biologischer Proben erlauben, durchgeführt werden.<br><br> In dieser Arbeit wurde zur Untersuchung der biochemischen Zusammensetzung von Tomatenwildarten und interspezifischen <i>S. pennellii</i> Tomatenintrogressionslinien (IL) eine GC/MS basierte Metabolitenanalyseplattform verwendet. Hierzu war es zunächst notwendig eine Massenspektrenbibliothek, zur Annotierung von Massenspektren und Retentionsindices von, in pflanzlichen Proben vorkommenden, Metaboliten anzulegen. Die Analyse der Tomatenwildarten ergab große Unterschiede gegenüber der Kulturtomate im Hinblick auf den Gehalt an Amino- und organischen Säuren, sowie der Zuckerzusammensetzung und den Gehalt an Sekundärmetaboliten. Die darauf folgende Analyse der ILs, von den jede ein genau definiertes genomisches Segment von <i>S. pennellii</i> beinhaltet, bestätigte diese enorme Variation mit 889 metabolischen und 326 ertragsassozierten-Veränderungen in den ILs. Die metabolischen Veränderungen zeichneten sich durch abnehmende bzw. steigende Gehalte von einzelnen Metaboliten, aber auch durch eine koordinierte Änderung aus. In dieser Arbeit wurde weiterhin der Biosyntheseweg der Volatilenstoffe Phenylethanol und Phenylacetaldehyd mit Hilfe einer IL untersucht. Hierbei konnten durch stabile Isotopenmarkierung und eines „reverse genetics“-Ansatzes Gene bzw. Enzyme identifiziert werden, die für die Dekarboxylierung des Eduktes Phenylalanin verantwortlich sind. Diese Arbeit beschreibt erstmals die umfassende Analyse von biochemischen Komponenten auf Genombasis in Tomatenintrogressionslinien und zeigt damit ein Werkzeug auf zur Identifizierung von qualitativen biochemischen Merkmalen in der modernen molekularen Züchtung.

There is an ever increasing need of new technologies for identification of molecular markers for early diagnosis of fatal diseases to allow efficient treatment. In addition, there is great value in finding patterns of metabolites, proteins or genes altered in relation to specific disease conditions to gain a deeper understanding of the underlying mechanisms of disease development. If successful, scientific achievements in this field could apart from early diagnosis lead to development of new drugs, treatments or preventions for many serious diseases.  Metabolites are low molecular weight compounds involved in the chemical reactions taking place in the cells of living organisms to uphold life, i.e. metabolism. The research field of metabolomics investigates the relationship between metabolite alterations and biochemical mechanisms, e.g. disease processes. To understand these associations hundreds of metabolites present in a sample are quantified using sensitive bioanalytical techniques. In this way a unique chemical fingerprint is obtained for each sample, providing an instant picture of the current state of the studied system. This fingerprint or picture can then be utilized for the discovery of biomarkers or biomarker patterns of biological and clinical relevance. In this thesis the focus is set on evaluation and application of strategies for studying metabolic alterations in human tissues associated with disease. A chemometric methodology for processing and modeling of gas chromatography-mass spectrometry (GC-MS) based metabolomics data, is designed for developing predictive systems for generation of representative data, validation and result verification, diagnosis and screening of large sample sets. The developed strategies were specifically applied for identification of metabolite markers and metabolic pathways associated with prostate cancer disease progression. The long-term goal was to detect new sensitive diagnostic/prognostic markers, which ultimately could be used to differentiate between indolent and aggressive tumors at diagnosis and thus aid in the development of personalized treatments. Our main finding so far is the detection of high levels of cholesterol in prostate cancer bone metastases. This in combination with previously presented results suggests cholesterol as a potentially interesting therapeutic target for advanced prostate cancer. Furthermore we detected metabolic alterations in plasma associated with metastasis development. These results were further explored in prospective samples attempting to verify some of the identified metabolites as potential prognostic markers.

This thesis is based on studies in which the suitability of various gas chromatography (GC) injection techniques was examined for the determination of polybrominated diphenyl ethers (PBDEs) and carbazoles, two groups of compounds that are thermally labile and/or have high boiling-points. For such substances, it is essential to introduce the samples into the GC system in an appropriate way to avoid degradation and other potential problems. In addition, different types of gas chromatographic column system and mass spectrometric detectors were evaluated for the determination of PBDEs. Conventional injectors, such as splitless, on-column and programmed temperature vaporizing (PTV) injectors were evaluated and optimized for determination of PBDEs. The results show on-column injection to be the best option, providing low discrimination and high precision. The splitless injector is commonly used for “dirty” samples. However, it is not suitable for determination of the high molecular weight congeners, since it tends to discriminate against them and promote their degradation, leading to poor precision and accuracy. The PTV injector appears to be a more suitable alternative. The use of liners reduces problems associated with potential interferents such as polar compounds and lipids and compared to the hot splitless injector, it provides gentler solvent evaporation, due to its temperature programming feature, leading to low discrimination and variance. Increasing the injection volume from the conventional 1-3 µL to &gt;50 µL offers two main benefits. Firstly, the overall detection and quantification limits are decreased, since the entire sample extract can be injected into the GC system. Secondly, large volume injections enable hyphenation of preceding techniques such as liquid chromatography (LC), solid phase extraction and other kinds of extraction. Large-volume injections were utilized and optimized in the studies included in this thesis. With a loop-type injector/interface large sample volumes can be injected on-column providing low risk of discrimination against compounds with low volatility. This injector was used for the determination of PBDEs in air and as an interface for the determination of carbazoles by LC-GC. Peak distortion is a frequently encountered problem associated with this type of injector that was addressed and solved during the work underlying this thesis. The PTV can be used as a large volume injector, in so-called solvent vent mode. This technique was evaluated for the determination of PBDEs and as an interface for coupling dynamic sonication-assisted solvent extraction online to GC. The results show that careful optimization of the injection parameters is required, but also that the PTV is robust and yields reproducible results. PBDEs are commonly detected using mass spectrometry in electron capture negative ionization (ECNI) mode, monitoring bromine ions (m/z 79 and 81). The mass spectrometric properties of the fully brominated diphenyl ether, BDE-209, have been investigated. A high molecular weight fragment at m/z 486/488 enables the use of 13C-labeled BDE-209 as an internal surrogate standard.

La pollution des eaux est particulièrement problématique pour les pays industrialisés et les pays en développement. Des suivis environnementaux se sont alors avérés nécessaires afin de progresser dans la compréhension des origines et des conséquences de la présence de ces polluants. Parmi les polluants organiques les plus dangereux, les Hydrocarbures Aromatiques Polycycliques (HAP) et les pesticides qui peuvent se retrouver à l'état de traces dans les milieux aquatiques. Leur analyse nécessite des méthodes analytiques à la fois spécifiques et sensibles. L'Extraction sur Phase Solide (SPE) suivi d'une analyse par la Chromatographie Gazeuse couplée à la Spectrométrie de Masse (GC-MS) est la méthode la plus couramment employée. Les travaux de thèse s'inscrivent ainsi dans l'optique générale visant à développer des nouvelles méthodes analytiques pour l'extraction et l'analyse de ces deux familles de polluants organiques présents dans l'eau. Afin de pallier les contraintes classiques de la SPE, une nouvelle approche a été développée qui consiste à introduire la technique de centrifugation dans certaines étapes de la procédure SPE. La nouvelle méthode élaborée a permis de réduire considérablement le temps de préparation et d'économiser l'utilisation et le rejet des solvants organiques, en réduisant presque 10 fois les volumes nécessaires à l'obtention des rendements de récupération satisfaisants. Une méthode d'analyse par injection à température programmable (PTV) a été optimisée afin d'améliorer les seuils de détection des HAP. Cette étude a permis également d'avoir les informations sur la qualité des eaux de pluie, eaux souterraines et eaux de surface au Liban quant au niveau de leur contamination pour les HAP et les pesticides.

In this study, the Persistent Organic Pollutants (POPs) specifically / 17 Organochlorine Pesticides (OCPs) and 19 Polycyclic Aromatic Hydrocarbons (PAHs) were evaluated in the sediment samples of Balikesir (Ikizcetepeler) Dam Lake. Sixteen sampling points were chosen for determination of concentrations of OCPs and PAHs After ultrasonic bath extraction of the sediment samples GC-MS was used as analytical tool. Extraction efficiencies changes from 63.8 to 87.4% depending on the type of the POPs. Average OCP concentration was found in the range of 3.33-379 &micro / g/kg a, average PAH concentration was found in the range of 3.28-32.9 &micro / g/kg. Pollution maps regarding OCP and PAH distributions were drawn and the correlation between these two pollutant types was investigated. The quality control (QC) and quality assurance tests were applied by the analysis of standard reference materials (SRMs), surrogate standards and analysis replicates.

Diss. (sammanfattning) Umeå : Umeå universitet, 2010. / Härtill 4 uppsatser.