L’appréciation par le consommateur d’un produit alimentaire comme le chocolat est en grande partie due à sa composante aromatique. La perception de cette composante est étroitement liée à la libération des composés d’arômes lors de la consommation du produit. Une étude sensorielle systématiquement menée par la société Valrhona dans une démarche de qualification de ses chocolats noirs de pures origines, fabriqués selon un procédé standard à partir de lots de cacao différents, permet de classer ces chocolats, selon leur profil, en quatre grands pôles sensoriels. Le travail entrepris avait pour but la compréhension de l’origine de cette classification sensorielle par la mise en œuvre de techniques de caractérisation des molécules volatiles responsables de l’arôme des chocolats.Dans un premier temps, l’empreinte globale en composés volatils d’un lot de 206 chocolats représentatifs des quatre pôles sensoriels a été obtenue via une méthode d’analyse couplant un headspace dynamique à la spectrométrie de masse en injection directe, utilisant l’ionisation par transfert de protons (PTR-ToF-MS). Des analyses multivariées des données, et notamment une analyse discriminante de type PLS-DA, ont permis d’élaborer un modèle de prédiction de la classification sensorielle des chocolats basé sur leur composition en molécules volatiles. Différentes méthodes de sélection de variables ont permis de souligner l’existence de composés volatils particuliers capables de discriminer les quatre pôles sensoriels de chocolats.Le potentiel aromatique de 12 chocolats parmi les 206 (trois de chaque pôle) a ensuite été déterminé suite à l’extraction des arômes par une méthode de distillation sous vide dans une analyse par chromatographie en phase gazeuse couplée, d’une part, à l’olfactométrie (GC-O) basée sur la fréquence de détection obtenue par 12 juges, et d’autre part, à un spectromètre de masse (GC-MS) pour l’identification des composés odorants. Ainsi, des composés d’arômes permettant de discriminer les différents pôles sensoriels ont pu être caractérisés au moyen d’une analyse factorielle des correspondances.Enfin, l’analyse « nosespace » d’un jury de 12 personnes dégustant 8 chocolats (deux de chaque pôle parmi les 12 précédents) a été réalisé en PTR-MS. Cette étude, couplée à une analyse sensorielle temporelle (Dominance Temporelle des Sensations, DTS), a permis d’obtenir des données temporelles instrumentales et sensorielles de manière simultanée. L’analyse DTS révèle dans une analyse en composantes principales (ACP) une bonne discrimination des pôles sensoriels, avec des descripteurs dominants similaires dans les pôles 1 et 4, d’une part, et dans les pôles 2 et 3, d’autre part. L’analyse nosespace a permis le suivi de la libération en temps réel de 26 composés d’arômes. La relation entre les deux jeux de données (instrumentales et sensorielles) a été étudiée au moyen de l’indice AWD (Abundance While Dominance) qui représente l’abondance de chaque ion pendant qu’une sensation est dominante. Des analyses factorielles des correspondances menées sur les AWD ont permis pour chaque échantillon de déceler des relations entre composés d’arômes libérés et sensations dominantes. / Consumers’ appreciation of chocolate is mostly due to its aromatic composition. Perception of this component is clearly linked to the release of aroma compounds during chocolate consumption. A systematic sensory evaluation is conducted by the Valrhona Company in order to qualify their pure origin dark chocolates manufactured according to a standard process from differing cocoa batches. The obtained sensory profiles allow classifying the chocolates into four sensory categories, named poles. The objective of the present work was to understand the molecular origin of this sensory classification by using techniques aimed at characterizing volatile organic compounds (VOC) responsible for chocolate flavour.Firstly, global VOC profiles of a set of 206 chocolate samples classified in the four sensory poles were analysed by a direct injection mass spectrometry method using proton transfer reaction as ionisation process (PTR-ToF-MS). A supervised multivariate data analysis based on discriminant analysis of the PLS-DA type allowed the construction of a classification model that showed excellent prediction capability based on VOC composition of the chocolates. Variable selection using dedicated methods pinpointed some volatile compounds important for the chocolates sensory discrimination.Then, the aroma potential of 12 chocolate samples (chosen among the 206 ones with three samples representative of each pole) was investigated on aroma extracts obtained by distillation under vacuum. Gas chromatography coupled to olfactometry (GC-O) and to mass spectrometry (GC-MS) was used to detect and identify the odorous compounds. GC-O data were obtained by 12 assessors using the detection frequency method. Aroma compounds allowing the discrimination of the sensory poles were determined thanks to a correspondence analysis.Finally, a nosespace analysis conducted by 12 assessors on 8 chocolates (two in each pole among the preceding 12) was realised using PTR-MS. This analysis was conducted simultaneously with a temporal sensory analysis (Temporal Dominance of Sensations, TDS), allowing temporal instrumental and sensorial data to be obtained. A principal component analysis (PCA) conducted on the TDS data revealed a good discrimination of the sensory poles, with similar dominant attributes in poles 1 and 4, on the one hand, and in poles 2 and 3, on the other hand. The nosespace data displayed real time release curves of 26 aroma compounds. The relationships between instrumental and sensory data were investigated thanks to the AWD (Abundance While Dominance) index that measures the abundance (area under the curve) of each ion during the dominance of a given sensation. Correspondence analyses of the AWD indices conducted for each chocolate sample allowed to define some relationships between dominant sensations and some released aroma compounds.

Submitted by Gizele Lima (gizele.lima@inpa.gov.br) on 2016-08-31T13:21:43Z No. of bitstreams: 2 Tese de Doutorado_Angela Beth Jardine.pdf: 6114980 bytes, checksum: 07a301793e0522e5fb0084e12ee425fe (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-08-31T13:21:43Z (GMT). No. of bitstreams: 2 Tese de Doutorado_Angela Beth Jardine.pdf: 6114980 bytes, checksum: 07a301793e0522e5fb0084e12ee425fe (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-05-10 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Plants produce and emit a large array of volatile metabolites termed biogenic volatile organic compounds (BVOCs) as an integral part of primary and secondary metabolism. Monoterpenes are BVOCs from the largest family of plant natural products, the terpenoids. Despite orders of magnitude difference in atmospheric reactivity and great diversity in biological functioning, little is known about monoterpene speciation in tropical forests. Using thermal desorption-gas chromatography-mass spectrometry techniques, twelve volatile monoterpenes were identified and quantified in a central Amazon terra firma rainforest including the first ambient air observations of the highly reactive cis-β-ocimene and trans-β- ocimene. At the ecosystem scale, monoterpene mixing ratios in the ambient air were greatest at the top of the canopy where light and temperatures are greatest. Leaf level monoterpene emissions were found to be light dependent among the Amazon trees sampled in the field. However, during drought stress conditions that led to leaf senescence, leaf monoterpene emissions were found to be first light dependent followed by temperature dependent and an acted as an early indicator of leaf lipid peroxidation. Further, leaf monoterpene emissions revealed a strong non-linear relationship with net photosynthesis (Pn), dedicating up to 2% of Pn to monoterpene emissions at leaf temperatures up to 30ºC and continuing to rise as leaf temperatures increased. These results suggest that highly reactive monoterpenes may play important roles as antioxidants protecting photosynthesis in plants and serve as near-canopy sources of secondary organic aerosol precursors through atmospheric photooxidation reactions. / As plantas produzem e emitem uma grande variedade de metabólitos voláteis denominados compostos biogênicos orgânicos voláteis (BVOCs), como parte integrante do metabolismo primário e secundário. Monoterpenos são BVOCs de a maior família de plantas produtos naturais, os terpenóides. Apesar de diferenças das ordems de magnitude na reatividade atmosférica e grande diversidade em funcionamento biológico deles, pouco se sabe sobre a especiação dos monoterpenos em florestas tropicais. Usando tecnicas analiticas de desorpção termica-chromatografia gasosa-espetrometria (TD-GC-MS), doze monoterpenos voláteis foram identificados e quantificados numa floresta tropical de terra firma na Amazônia central, incluindo as primeiras observações no ar ambiente dos monoterpenos que são altamente reativos, cis-β-ocimeno e trans-β-ocimeno. Na escala do ecossistema, as taxas de mistura dos monoterpenos no ar ambiente foram maiores no topo do dossel onde a luz e as temperaturas são maiores. No nível das folhas, emissões dos monoterpenos foram dependente da luz para as avores foram amostradas em campo. No entanto, durante as condições de seca com estresses que levaram a senescência foliar, as emissões dos monoterpenos das folhas foram dependente primeiro da luz e depois a temperatura e agirem como um indicador da peroxidação lipídica folha. Além disso, as emissões dos monoterpenos das folhas revelou uma forte relação não-linear com fotossíntese líquida (Pn), dedicando-se a 2% do Pn para as emissões dos monoterpenos nas temperaturas das folhas até 30ºC e continuaram a aumentar com as temperaturas da folha. Estes resultados sugerem que os monoterpenos o que são altamente reativas podem ser importantes porque eles funçiõnam como antioxidantes que protegem a fotossíntese nas plantas e também podem ser fontes perto do dossel dos precursores dos aerossóis orgânicos secundários de fotooxidação na atmosfera.

The Middle Ordovician to Late Silurian represents an interval of approximately 50 million years, which has been recognised as the initial, cryptic, period in the evolutionary history of chondrichthyan fish. The fossil remains attributed to early chondrichthyans are dominated by isolated dermal scales that predate the appearance of undisputed chondrichthyan teeth and articulated skeletons in the Lower Devonian. Investigation of the inter-relationships of these scale taxa and their systematic position relative to high- ranked chondrichthyan clades has been hampered by the lack of developed scale-based classification schemes for jawed gnathostomes, coupled with the limited use of scale characters in phylogenetic studies of Palaeozoic Chondrichthyes. Here, all previously documented scale types of alleged Lower Palaeozoic chondrichthyans were examined using a combination of X-ray microtomography, SEM and Nomarski DIC optics. These were found to exhibit a set of characteristics (symmetrical trunk scales, areal crown growth and lack of hard-tissue resorption, cancellous bone and enamel) recognised as specific to the dermal skeleton of chondrichthyans among derived gnathostomes. The collected data permitted the establishment of a hierarchy of scale characters for separate taxonomic ranks, leading to the recognition of three Orders (Mongolepidida, Elegestolepida ordo nov. and Altholepida ordo nov.) of early chondrichthyans, differentiated by distinct types of scale-crown morphogenesis. A scale-based cladistic analysis of jawed gnathostomes corroborated these results by recovering a chondrichthyan clade that incorporates all examined taxa and ‘acanthodians’ with non-superpositional crown growth patterns. It is thus proposed that chondrichthyan dermoskeletal characters carry a phylogenetic signal, allowing to interpret the documented diverse types of scale morphogenesis as evidence for a major radiation of chondrichthyan lineages in the Lower Palaeozoic.

Studies have shown that faults exhibit complex geometries that are often highly simplified and cross sections may not be sufficient to highlight the spatial variation of fault surface topography and the complex relationship with the wall rock. The main contributions of this thesis to structural geology are novel methods for investigating links between fault shape and wall rock structure. Curvature plots of sixteen faults show that thrust faults in deepwater Niger Delta exhibit corrugations on a range of wavelength and amplitude. The corrugations are characterized by large-scale anticlastic and synclastic geometries parallel to fault transport direction. The structure of the volumes in the immediate vicinity of the faults was investigated using slices of seismic attribute data sampled parallel and adjacent to thirteen faults. In half of the faults the hanging wall is more disrupted than the footwall, while in the other half the footwall is more disrupted than the hanging wall, implying that thrust zones exhibit complex geometries that existing models have yet to address. In addition, disruptions near fault surfaces may be related to discrete zones of intense fault surface maximum curvature, anomalous surface gradient and change in pattern of anticlastic and synclastic fault Gaussian surface curvature in the fault transport direction. No significant wall rock disruption was observed where fault surface curvature is planar.

Lungenkrebs ist die führende Todesursache unter den Krebstodesfällen. Vor allem in späten Stadien diagnostizierter Lungenkrebs ist schwer zu behandeln und mit einer schlechten Prognose vergesellschaftet. Daher ist es wünschenswert, die Tumorerkrankung möglichst früh zu diagnostizieren und idealerweise in einem Screening-Test finden zu können. In der hier vorliegenden Studie wollten wir die Frage klären, ob ein von der Firma Sony neu entwickeltes Messverfahren SonyNose-G2_SN8 für die Untersuchung von Atemluft und für die Diagnose von Lungentumoren geeignet ist. Für die Studie wurden Atemproben von insgesamt 124 Probanden gesammelt, davon 65 gesunde Studienteilnehmer, 43 Patienten mit histologisch gesichertem Lungenkrebs, 10 Patienten mit COPD und 6 Studienteilnehmern mit nicht lungenkrebsspezifischen Raumforderungen. Die Atemproben wurden innerhalb von 20 Minuten nach Probennahme analysiert. Als Referenz zur getesteten Atemprobe wurde ein Luftgemisch aus gereinigter Luft mit 50%-iger Luftfeuchtigkeit verwendet. Technisch handelt es sich bei der Auswertung um eine gaschromathographische Prüfmethode. Außerdem wurden zusätzliche Atemproben von den Patienten bzw. Probanden gesammelt, um diese mittels GC-MS-Messungen auf ihre volatilen organischen Bestandteile hin zu überprüfen. In den GC-MS-Untersuchungen der Atemproben konnten 263 verschiedene chemische Verbindungen identifiziert werden. Davon konnten 20 Substanzen ermittelt werden, die sich signifikant zwischen der Gruppe „Gesund“ und der Gruppe „Lungenkrebs“ unterschieden. Diese Substanzen könnten sich folglich als Marker für den Lungenkrebs eignen. Weitere Untersuchungen sind zur Überprüfung dieser Hypothese jedoch erforderlich. Nicht zuletzt aufgrund von Problemen mit der Stabilität einzelner Sensoren, war es mit der SonyNose-G2_SN8 nicht möglich, zwischen Lungenkrebs-Patienten, Patienten mit COPD und gesunden Probanden zu unterscheiden. Das getestete Gerät eignet sich also nicht für das Lungenkrebs-Screening im klinischen Einsatz. Auch nach der hier vorliegenden Untersuchung bleibt offen, ob Analyseverfahren zur Atemluftdiagnostik als Screening-Methode zur Früherkennung von Lungenkrebs grundsätzlich geeignet sind. Der Einsatz der gaschromatographischen-massenspektrometrischen Untersuchungsmethode ist für die Routinediagnostik derzeit noch zu zeitaufwendig und zu teuer. Die Identifikation möglicher krebsspezifischer volatiler organischer Verbindungen in der Atemluft von Patienten bleibt für die Forschung weiterhin eine offene und vielversprechende Thematik. / Lung cancer (LC) is the leading cause of cancer death worldwide. Results of therapeutic interventions are not satisfying because the disease is diagnosed in an advanced stage in more than 50% of the patients. Early diagnosis is limited by the fact that the disease usually develops asymptomatically and no screening methods are available. Previous studies have shown correlations between the chemical composition of the exhaled breath of an individual and the presence of LC. The Sony Materials Science Laboratory developed the "electronic nose" SonyNose-G2_SN8 for breath analysis that was tested in a clinical study to evaluate its suitability for LC diagnosis. The SonyNose was tested in a prospective clinical study (proof of concept study). The study was approved by the Etics committee of the University of Tuebingen [project 010/2012BO1). Breath samples from patients with COPD or suspected LC and from healthy individuals were collected. Inclusion criteria were males and females, aged 18-80 yrs, and signed informed consent. Exclusion criteria were suspected or confirmed malignant disease other than lung cancer, previous thoracic surgery and any medical interventions at the chest or the airways within the preceding 14 days. The study participants were classified into four groups: Group A- healthy; Group B-lung cancer; Group C-COPD; Group D-non malignant pulmonary nodule. The decision whether a patient was assigned to the cancer group B was made on the basis of histology of a tumour biopsy or the resected tumour after breath sample analysis. Breath samples were collected in gas sampling bulbs ("gas mouse") provided by Sony. Two gas mice were obtained per person. Reference bulbs were filled with a standardized gas. Additionally, cylindrical glass tubes that have been applied in a successful previous study of Prof. Walles were used for breath sampling. The gas mice were analyzed within 20 min at the Schillerhoehe Hospital using the SonyNose. The glass tubes were stored up and analyzed by gas-chromatography and mass spectrometry (GC-MS) at the Sony Materials Science Laboratory. Altogether, 124 participants were enrolled: 65 healthy individuals (group A), 43 patients with histologically confirmed LC (group B), 10 patients with COPD (group C) and 6 patients with non malignant pulmonary nodules. Breath sample analysis using the SonyNose revealed an instability of the sensor array. Some sensors had to be replaced in the course of the experiments. Intra-individual controls that were performed by testing the same patient repeatedly showed a very high intra-individual variation of the sensor signal and a very low reproducibility. GC-MS analysis were performed in only 27 individuals, because the R&D agreement was cancelled in the course of the study (Group A:9; Group B:11; Group C:1; Group D:6). In the analyzed breath samples, 263 different compounds were identified. In Group B 20 compounds showed a different distribution pattern than in other groups. Of these, 6 have been described as LC associated in previous studies. The small number of tested individuals restricts a conclusive assessment of the generated data. The SonyNose-G2_SN8 is not suitable for a clinical breath sample analysis in the technical configuration tested in our study. GC-MS measurements revealed 20 potential candidates for LC specific markers in the breath of patients. However, the small number of tested individuals limits the validity of our analysis.

<p>New energy resources that can replace petroleum diesel are needed and biodiesel may be an excellent substitute. During storage and use, biodiesel can oxidize and form peroxides, leading to degradation of the fuel. It is therefore important to determine the peroxide content of the fuel. In this thesis the triphenylphosphine method, which involves GC-MS analysis has been compared to the standard iodometric method which involves titration with sodium thiosulfate. Working standards were made to see how well the iodometric method worked and also in order to make a calibration curve in GC-MS. Aged samples were then analyzed. The results showed that both methods gave good linearity and repeatability with limits of detection (LOD) and quantification (LOQ) of 0,06 mM and 0 17-0,65 mM respectively. However, the iodometric method seemed more circumstantial since it needed a lot of solvents and different reagents. The triphenylphosphine method was on contrary very simple to use and did not require too much preparation work. The latter also showed better reproducibility. In conclusions, both methods can be used in evaluating the peroxide content of biodiesel, but the triphenylphosphine method has the advantages of higher simplicity and better reproducibility.</p>

In any oil production company, one of the problems that is faced on a daily basis and which sometimes hinders the operation is corrosion. In the presence of dissolved oxygen in the water inside any vessel, tank, or pipeline, the oxygen attacks the steel to form iron oxides, and this result in corrosion of the steel. To prevent this, corrosion inhibitors are added to the oil and gas streams. These chemicals are based on aliphatic amines, which are soluble in water, to form a film to coat the steel and prevent it from the oxygen attacks. As a chemist in the laboratory, filming amines residuals should be monitored and optimized in order to make sure the system is protected against corrosion and that no excess chemical remains. This is classically done by lengthy liquid-liquid extraction of filming amines followed by colorimetric determination using spectrophotometry of the extract. SPME is an easy, rapid, and solvent free extraction technique which can be easily coupled with GC for separation and quantification, and is a good candidate to be used for this job. In this thesis, an introduction about corrosion problems and how to control and monitor them in the oil and gas industry will be shared, as well as a literature review about various methods used to determine amines in different matrices, followed by a description of the SPME procedure, including its theory, modes, fibers, and method development procedures. A flow-through system was used to simulate the process of flowing streams in pipelines during oil production and to provide unlimited sample volumes, which contributes iv to simplifying the calculation of the distribution constant between fiber and solution. Two different agitation methods were compared, which are stirring and sonication, in order to optimize the extraction time profiles of analytes. A method was developed to determine amines, using a flow-through system at the lowest detection limit possible. Different parameters were examined such as variation of pH, salt addition, and sand addition. It was found that the pH of the solution has to be adjusted in order to get better sensitivity for the desired analytes. Finally, in-fiber kinetic calibration was used to calculate the concentration of solutions at a short extraction time. This was possible by applying the dominant desorption approach using the same analytes as standards in the fiber. The experiment was successful in shortening the extraction time from 3 hours to 20 minutes, with less than 20% variation in concentrations between the actual and the calculated.

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The international harbors and fishing ports in Taiwan are nearly not installed the wastewater or oil treatment facilities, which would cause the ocean pollution by the ballast and bilge water from the boats. The purpose of this research is to study the feasibility of treatment of diesel fuel and the polycyclic aromatic hydrocarbons (PAHs) in diesel by aerobic biofiltreation in salty environment. According to the experimental results, the mineral oil and PAHs in the diesel fuel present high good removal efficiencies. Both of the contaminants were decomposed fast at the first 8 hours, and then slow down. The emulsified diesel fuel were found able to be reduced 83% within 8 hours, and the concentrations of phenanthrene would found decreased from 1.5 to 0.1 mg/L. After 8 hours, we observed that the PAHs with high number of rings kept a mild diminish trend, while the PAHs with less rings exhibited arrearage and irregular indicated by some peaks appearing in the chromatography diagram of HPLC, which were not found in the diagram in the initial of test run. In conclusion, the aerobic biofiltreation systems were found able to degrade n-alkanes and PAHs in diesel fuel effectively. Thus we suggested to install the systems at the greasiness accepting facilities in the harbor. However, we still have to keep studying the influence of the interrelationship between the contaminants in diesel fuel and the environment factors.

Zugl.: Hohenheim, Univ., Diss., 2009