Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants and are mostly products of the incomplete combustion of organic material. PAHs are often found in environmental samples as a complex mixture of isomers. In addition, the same sources that produce complex PAH mixtures also produce other poorly characterized mixtures of organic compounds, commonly referred to as an unresolved complex mixture (UCM), that act as matrix interferences in the chromatographic analysis of samples. Conventional one-dimensional chromatographic techniques, such as gas chromatography coupled to mass spectrometry (GC/MS), are not sufficient for the analysis and quantitation of complex PAH mixtures present in environmental samples due to the high degree of overlap in compound vapor pressures, boiling points, and mass spectral fragmentation patterns. Therefore, the separation and quantitation of complex mixtures of individual PAH compounds in environmental samples requires high chromatographic resolution. Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC��GC/ToF-MS) was used for this study. GC��GC/ToF-MS uses two different gas chromatographic columns, with different separation mechanisms, for the analysis of complex environmental samples. In theory, the peak capacity in GC��GC/ToF-MS is equivalent to the product of the individual peak capacities of each column used. However, in practice, this is rarely obtained because of the existing correlation between the two GC columns used. This dissertation is a compilation of three studies related to analytical method development for the identification and quantitation of complex PAH mixtures (including parent-PAHs, alkyl-PAHs, oxy-PAHs, nitro-PAHs, thio-PAHs, chloro-PAHs, bromo-PAHs and PAHs with molecular weight higher than 300 Da) that may be present in environmental samples using novel column combinations in GC��GC/ToF-MS. The use of a liquid crystal column (LC-50) in the first dimension, followed by a nano-stationary phase column (NSP-35) in the second dimension, was evaluated for the separation of a standard PAH mixture containing 97 different PAHs. Two standard reference materials purchased from NIST (NIST SRM1650b ��� Diesel Particulate Matter and NIST SRM1975 ��� Diesel Extract) were used, after extraction and cleanup, for method validation and comparison between the commonly used non-polar �� polar column combination and the LC-50 �� NSP-35 column combination with high orthogonality. As part of the method validation, an aliquot of NIST SRM1975 (Diesel extract), without sample cleanup was also analyzed for PAHs, showing that the LC-50 �� NSP-35 column combination was accurate (with an average absolute percent difference of approximately 30%) for the identification and quantitation of complex PAH mixtures in environmental samples, with reduced sample preparation prior to analysis. In addition, the LC-50 �� NSP-35 column combination was used for the analysis of PAHs sorbed to polystyrene pellets deployed in an urban bay area as passive water samplers because one-dimensional GC/MS was ineffective due to the presence of a strong unresolved complex mixture (UCM) and matrix interferences. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from Dec. 27, 2012 - June 27, 2013

This thesis deals with the passive sampling of polar compounds from water using passive samplers POCIS (Polar Organic Chemical Integrative Sampler). These devices were exposed for 4 weeks in the waste water at the inflow of municipal waste water treatment plant in Brno – Modřice, and also at the outflow of the treated water. After exposition sequestered compounds were released by extraction with a mixture of methanol, toluene and dichlormethane. Extracts were analysed by liquid chromatography/mass spectrometry with electrospray ionization. Further, methylated and trimethylsilylated extracts were analysed by orthogonal comprehensive two-dimensional gas chromatography with mass spectrometric detection. Separated compounds were identified on the base of their retention and mass spectra.

The diploma thesis will be focuses on the isolation of fragrances of natural origin by steam vapor distillation, ultrasonic extraction, microwave extraction and pressure solvent extraction. The extracts were characterized by GCxGC/TOF-MS. To study the surface structure of the leaf by SEM, a sample of the medulla medical was selected. Photos were taken before and after extraction.

Le fromage fondu est issu de la seconde transformation du lait. Sa fabrication implique le mélange, le chauffage et la texturation de produits laitiers (fromage, beurre et poudres de lait) et non laitiers (agents émulsifiants, acide citrique et chlorure de sodium). Le résultat est un produit homogène, généralement tartinable et à la durée de conservation longue, souvent supérieure à 6 mois. Au cours de la fabrication et du stockage, les réactions d’oxydation des lipides, de caramélisation et de Maillard forment des composés odorants dont certains sont potentiellement indésirables pour la flaveur du produit. Dans le cadre du projet ANR-06-PNRA-023 Réactial, une démarche méthodologique a été mise en place afin : (i) d’identifier les marqueurs réactionnels précurseurs ou responsables des défauts de flaveur observés, (ii) de suivre l’évolution de ces marqueurs au cours des traitements thermiques appliqués, (iii) d’établir un schéma réactionnel observable en vue (iv) de la modélisation et de la prédiction de l’évolution des marqueurs réactionnels et indirectement de l’apparition de défauts de flaveur. Ceci a nécessité la mise au point d’une formulation de matrice de fromage fondu modèle ainsi que l’élaboration d’une cellule de traitement thermique. Différents couplages de chromatographie en phase gazeuse à l’olfactométrie ont été utilisés afin d’identifier les composés odorants. La chromatographie bidimensionnelle systématique couplée à la spectrométrie de masse à temps de vol a permis une semi-quantification des composés traces et ultra-traces tandis que les précurseurs ont été quantifiés par chromatographie liquide haute performance. Les données ainsi obtenues ont permis l’écriture d’un schéma réactionnel observable qui a donné lieu à une modélisation stoechio-cinétique multi-réponses. Un ajustement des données expérimentales par le modèle a pu être réalisé malgré une quantification partielle des différents constituants. / Processed cheese derives from a secondary milk processing step that involves mixing and heating dairy (cheese, butter and milk powders) and non-dairy products (emulsifiers). This processing yields a homogeneous product, usually spreadable, with a shelf-life often longer than 6 months. During processing and storage, lipid oxidation, caramelization and Maillard reactions occur and produce odour-active compounds. Some of them are potentialy involved in the development of odour defects. As part of the ANR-06-PNRA-023 Réactial project, a methodological approach was used in order to (i) identify key compounds responsible for the flavor defects observed, (ii) monitor the evolution of these markers during the heat treatment applied to the cheese matrix, (iii) establish an observable reaction scheme, (iv) model and predict the evolution of these compounds during thermal operations. To do this, a model cheese and its cooking cell were elaborated. Various couplings of gas chromatography with olfactometry were used to identify odorous compounds. Two-dimensional comprehensive chromatography allowed a semi-quantitation of trace and ultra-trace compounds, while precursors were quantitated by high performance liquid chromatography. An observable reaction scheme was extracted from these data and make the multi-response modelling step possible despite a partial quantitation of the volatile compounds.

This diploma thesis deals with Bisphenol A, especially with its impact on the aquatic ecosystem. Information about its properties, production and current use are summarized here. Its harmful impact on the environment, especially on the aquatic ecosystem and the human body is characterized. Also the methods of its degradation within the aquatic environment have been described. A summary of the options of a determination of Bisphenol A in water samples is incorporated and the method of gas chromatography with mass spectrometry (GC/TOF MS) and comprehensive two-dimensional gas chromatography with mass spectrometry (GCxGC/TOF-MS) is compared in the experimental part. Analytical determination precedes the isolation of the analyte from the water samples by solid phase extraction (SPE) using SupelcleanTM ENVITM - 18 and derivatization using the silylation reagent, N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). The result of this work is the analysis of a series of real samples from wastewater treatment plants Brno Modřice and Luhačovice by a two-dimensional gas chromatography with mass spectrometry (GCxGC/TOF-MS).