Carotenoids are natural pigments occurring in plants and many microorganisms, such as algae, yeast and bacteria. They represent the most common group of antioxidants with significant biological effect. Lipids are an essential component of all living organisms. They are the source and the reservoir of energy for organisms, which can also be used in the petrochemical industry for the production of biofuels. This thesis deals with the production properties of carotenoids and lipids by selected strains of yeasts, algae, and canobacteria, in order to apply the acquired knowledge and find cheap suitable alternatives for microbial biotechnological production of these metabolites using waste substrates. Carotenoids, coenzyme Q, and ergosterol in cells were determined by liquid chromatography. The lipid content and fatty acid profile was analyzed by gas chromatography. Cell morphology and localization of selected metabolites were analyzed by fluorescence lifetime imaging microscopy. In this work yeast genera Sporobolomyces, Cystofilobasidium and Rhodotorula were used. As the representatives of the algae and cyanobacteria strains of Desmodesmus, Cyanothece, Chlamydomonas, Synechoccocus and Chlorella strains were studied. In the overall comparison, the yeast strains were more productive than algae and cyanobacteria. The highest carotenoid production was found in S. pararoseus, C. capitatum and R. mucilaginosa cells, while the highest lipid yield was observed in strains of C. infirmominiatum and S. metaroseus.

The diploma thesis deals with the monitoring of oxidative stability of products, oils and butter, from nut fruits. The theoretical part concentrates on the topic of nut fruits, their properties, compositions which are closely related to the effects on the human health and the possibilities of technological processing. The lipid storage process, especially the most frequently occurring autooxidation reactions are described, followed by experimental part of the thesis. The changes in coconut, walnut, peanut oils and peanut butter samples are monitored during storage at 4 ° C and 20 ° C by determining the acid value, the peroxide value and the fatty acid composition by the GC-FID method. The lowest oxidation stability showed walnut oil due to the highest content of unstable polyunsaturated fatty acids – up to 88,7 %. During storage at 20 ° C there was a statistically significant increase in the content of primary oxidation products, determined as peroxide value PV = 2,55 ± 0,12 µgROOHg-1. An increase was also observed in samples of peanut butter, but it was mainly due to higher water activity, which is important for chemical reactions. The durability of this product after opening mentioned on the product label correlates with their low stability

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.

“Green” explosives are an important sub-family of explosives due to the banning of explosives based on heavy metals, such as lead azide and lead styphnate, according to the REACH list. A substitute to lead azide is potassium 4,6-dinitrobenzofuroxane (KDNBF) which is an alternative “green” explosive. Hence there is an upcoming need for analytical and quality control protocols for KDNBF. In this report is HPLC-UV/VIS, GC-FID and potentiometric titration evaluated for their suitability as methods for testing of KDNBF. The results implies that KDNBF can be analyzed by GC-FID, when dissolved in DMSO and caffeine is used as internal standard. To analyze KDNBF by HPLC-UV/VIS was isocratic mode used together with a porous graphitic carbon (PGC) (Hypercarb ®) column. However, degradation of the analyte was severe and quantitative results were not obtained. Potentiometric titration indicated that KDNBF equilibrate with four hydrogen ions during titration, instead of the one to one ratio with potassium and hydrogen ion, as in previously proposed theory. Despite this and with careful titration is potentiometric titration and GC-FID analysis combined suitable as a quality control protocol for KDNBF.

Thesis (DPhil (Chemistry))--Cape Peninsula University of Technology, 2019 / Occurrence of polycyclic aromatic hydrocarbons (PAHs) in freshwater systems may aggravate the water crisis currently being experienced in the Western Cape province of South Africa. However, there is dearth of data on the levels of PAHs, necessary for effective assessment of water quality as well as remediation strategies. This study therefore assessed levels of PAHs in two important freshwater systems in the Western Cape Province, South Africa. The potential of grape leaf litter for PAH abatement was also investigated. A solid-phase extraction - gas chromatography - flame ionisation detection (SPE-GC-FID) method was developed to simultaneously determine the 16 United States Environmental Protection Agency (US EPA) priority PAHs in environmental samples. Levels of 16 US EPA priority PAHs were assessed in water, sediment and plants from seven selected sites on the Diep and Plankenburg Rivers. Seasonal variations of some water quality parameters and PAHs levels in water and sediment samples were determined from the selected sites. Activated carbons produced from Vitis vinifera (grape) leaf litter were utilised for PAH-remediation. The SPE-GC-FID method developed for the 16 US EPA priority PAHs determination gave acceptable linearity (R2 > 0.999). Instrument detection limits ranged between 0.02 and 0.04 µg/mL and instrument quantification limits of between 0.06 and 0.13 µg/mL. Recovery studies were also acceptable (70.35 - 100.83%) with the exception of naphthalene that had lower recoveries. The average ∑16 PAHs detected in water samples at a given site, over a one-year period ranged from 73.90 to187.11 µg/L. The highest PAHs levels were detected in water samples from industrial areas of both rivers; chrysene (Chy) followed by benzo[a]anthracene (BaA) were the most abundant PAHs detected in water samples. Higher PAHs levels were detected in sediment samples relative to water samples; the average ∑16 PAHs detected in sediment samples at a given site, over a one-year period ranged from 6.048 to 39.656 µg/g. PAHs levels were also highest in sediment samples from industrial areas of the two rivers; benzo[b]fluoranthene (BbF) followed by benzo[k]fluoranthene (BkF) were the most abundant PAHs detected in sediment samples. The average ∑16 PAHs detected in plant samples [Phragmites australis (common reed) and Eichhornia crassipes (water hyacinth)] at a given site, ranged between 62.11 and 226.72 µg/g. Highest levels of PAHs were therefore detected in plant samples, suggesting possible bioaccumulation of PAHs in plant tissues. The bioaccumulation of PAHs by the plants also indicates the phytoremediation potential of these plants for PAHs remediation. The levels of PAHs measured in water and sediment samples were subjected to probabilistic risk assessment to predict the possibility of regulatory values being exceeded. The average percentage exceedence of 63.26 and 42.81 were obtained for PAHs in water samples of the Diep and Plankenburg Rivers respectively, while the corresponding average percentage exceedence obtained for sediment samples were 63.71 and 77.20. Vitis vinifera (grape) leaf litter showed enormous prospect as precursor for activated carbon. The yield of activated carbons obtained from grape leaf litter ranged from 44.65 to 58.40% and the Brunauer-Emmett-Teller (BET) surface area of up to 616.60 m2/g was obtained for activated carbons. The estimated adsorption capacities of the ZnCl2 and H3PO4 activated carbons for phenanthrene removal from aqueous solutions were 94.12 and 89.13 mg/g respectively. The environmental samples analysed were heavily contaminated with the 16 US EPA priority PAHs and the probabilistic risk assessment suggested risks of the carcinogenic PAHs at the levels measured in the environment. Vitis vinifera leaf litter, showed enormous potential as renewable precursor for activated carbon production, capable of removing varied contaminants from wastewater.

This paper studies castor oil’s potential as a biodiesel feedstock. Base-catalyzed transesterification batch reactions were conducted at various experimental conditions while measuring the concentration of the reaction components over time. A gas chromatograph with a flame-ionization detector analyzed these samples. A factorial design of experiments was used to determine how conversion was affected by reaction temperature, sodium methoxide concentration, and ratio of methanol to oil. Conversion was maximized (0.9964) at 30 °C, 0.5% catalyst, and 9:1 molar ratio. The concentration data were used to study the reaction kinetics. Modeling the reaction as three equilibria yielded six rate constants. These values indicate that castor oil transesterifies faster than soybean oil. The fuel properties were determined by ASTM D 6751. Viscosity was excessively high, but specifications were met for the remaining tests. Despite the promising yield and kinetics of the reaction, the fuel viscosity limits castor oil’s viability as a biodiesel feedstock.

No description available.

<p>  This dissertation focuses on the examination of the influence of sample storage conditions on the accuracy and precision of hydrocarbon composition measurements of Jet A made with GC×GC/FID and the accuracy and precision of flash point measurements of Jet A made with a Tag closed cup flash point tester. Areas of focus also include the influence of the column load value used, the S/N threshold value used, and the number of measurements made for a single sample vial on the accuracy and precision of the GC×GC/FID results. This dissertation also describes the development of an analytical method for the identification and quantitation of alkylphenols in Jet A (which are the most abundant heteroatom containing compounds in jet fuel) by using preparative high-performance liquid chromatography (prep-HPLC) and two-dimensional gas chromatography with electron ionization time-of-flight mass spectrometry (GC×GC/(+)EI TOF MS).</p>

Os hidrocarbonetos policíclicos aromáticos nitrados (nitro-HPAs) são potencialmente genotóxicos, por isso existe um grande interesse na determinação analítica desses compostos no material particulado no ar. Os nitro-PAHs são emitidos diretamente para a atmosfera pela combustão incompleta ou podem ser formados in situ a partir dos HPAs precursores. Neste trabalho, são apresentados os resultados obtidos no desenvolvimento de um método de análise de nitro-HPAs (1-nitronaftaleno, 2-nitronaftaleno, 1-nitropireno, 2-nitropireno, 2-nitrofluoranteno, 3-nitrofluoranteno, 1,3-dinitropireno, 1,6- dinitropireno, 2-nitrofluoreno, 6-nitrocriseno, 7-nitrobenzo(a)antraceno, 9- nitroantraceno e 9-nitrofenantreno) por GCxGC. A separação destes compostos por GCxGC pode simplificar a etapa de pré-tratamento do extrato orgânico oriundo do material particulado no ar. A GCxGC promove a separação em duas colunas com mecanismos de separação diferentes, conectadas em série, o que resulta em uma capacidade de separação maior. O sistema GCxGC empregado neste trabalho possui um injetor com programação de temperatura (PTV), um modulador criogênico de dois jatos de CO2 líquido (Dual Jet) e um detector por ionização em chama (FID). A separação foi feita empregando a fase estacionária apolar 5% fenil polisilfenilene siloxano na primeira coluna (30 m / 0,25 mm / 0,25 &#181;m) e a semipolar 14% cianopropilfenil polisiloxano na segunda coluna (1 m / 0,10 mm / 0,10 &#181;m). Diferentes condições cromatográficas foram testadas, como: programação de temperatura no PTV, de 40-90ºC até 350ºC, com taxa de aquecimento de 2,2 e 14,5ºC/s; programação de temperatura no forno, de 40-90ºC até 300ºC, com taxa de aquecimento de 2, 2,5 e 3ºC/min; períodos de modulação de 3, 4 e 5s. O volume injetado foi 2&#181;L, no modo splitless; a vazão do gás de arraste (He) foi constante e igual a 1 mL/min e o detector FID foi operado em 120 Hz. As larguras de pico medidas em 10% da altura variaram de 167 a 350ms para 1- nitronaftaleno e 6-nitrocriseno, respectivamente, e a capacidade de pico para o conjunto de colunas de separação usado foi estimada em cerca de 9800. Parâmetros de validação, tais como os limites de detecção (200 a 500 ng/mL) e de quantificação (650 a 1600 ng/mL) para alguns nitro-HPAs foram determinados. Para a quantificação, foram testados os métodos por padronização interna e externa, sendo que, através dos resultados deste trabalho, pode-se mostrar que a determinação de nitro-HPAs por GCxGC com o modulador empregado é possível se for feita através do método de padronização interna. O sistema GCxGC empregado causou dificuldades operacionais, principalmente na conexão das colunas e na modulação. Perdas de massa de analito foram detectadas nas análises por GCxGC, muito provavelmente causadas por uma conexão parcial das colunas. Isso poderia ser evitado se a conexão fosse feita pela fusão das colunas a um conector de vidro adequado a essa finalidade. Picos modulados divididos foram observados com frequência, o que comprometeu a precisão e exatidão dos resultados. A divisão dos picos ocorreu de modo aleatório dificultando a identificação da causa mais provável para a sua ocorrência. Cromatogramas GCxGC de extratos orgânicos não fracionados de particulados no ar, oriundos de queima direta de palha de cana-de-açúcar, de região afetada pela queima de cana-de-açúcar e de área urbana da cidade de São Paulo, mostraram a potencialidade do método / Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) are potentially genotoxic, so there is a great interest in the analytical determination of these compounds in airborne particulate matter. The nitro-PAHs are emitted directly into the atmosphere by incomplete combustion or may be formed in situ from PAHs. In this work, results obtained from the development of an analytical method for nitro-PAHs by GCxGC are presented. The nitro-PAHs studied were: 1- nitronaphthalene, 2-nitronaphthalene, 1-nitropyrene, 2-nitropyrene, 2- nitrofluoranthene, 3-nitrofluoranthene, 1,3-dinitropyrene, 1,6-dinitropyrene, 2- nitrofluorene, 6-nitrochrysene, 7-nitrobenzo(a)anthracene, 9-nitroanthracene and 9- nitrophenanthrene. The separation of these compounds by GCxGC should simplify the pretreatment step of the airborne particulate organic extract. In GCxGC two capillary columns of different mechanisms of separation are coupled by an interface called modulator, which increase significantly the chromatographic resolution. The GCxGC system used in this work is equipped with a PTV injector, a dual-stage double jets CO2 cryogenic modulator and a flame ionization detector (FID). The separation was carried out using a nonpolar stationary phase 5% methyl phenyl polysiloxane in the first column (30 m / 0.25 mm / 0.25 &#181;m) and a semipolar 14% cyanopropyl phenyl dimethyl polysiloxane in the second column. Different chromatographic conditions were tested: the PTV was programmed from 40-90ºC to 350ºC at 2.2 and 14.5ºC/s; the oven was programmed from 40-90ºC to 350ºC at 2.0, 2.5 and 3.0ºC/min; the modulation periods tested were 3, 4 and 5s. The injected volume was 2&#181;L in splitless mode, the carrier gas (He) flow rate of 1 mL/min was constant and the FID detector was operated at 120 Hz. Validation parameters, such as the limit of detection (200 - 500 ng/mL) and quantitation (650 - 1600 ng/mL) were determined. For quantification, the internal and external standardization methods were tested, and through the results of this study, it can be shown that the determination of nitro-PAHs by GCxGC with the modulator used is possible if made by internal standardization method. The GCxGC system presented operational difficulties, particularly in the column connection and in the modulation zone. A partial connection of the columns resulted in mass loss of the analytes. The connection of the columns could be more effective if it was made by fusing the columns to a glass connector suitable for this purpose. Divided modulated peaks were frequently observed, which compromised the precision and accuracy of the results. The division of the peaks occurred randomly hindering the identification of the most likely cause for its occurrence. GCxGC chromatograms corresponding to unfractionated organic extracts of airborne particulate material from the sugarcane straw burning, from an area impacted by sugar cane burning emissions and from an urban area of São Paulo City showed the capability of the method.

L’objectif de ces travaux de thèse était l’étude des interactions de petites molécules avec les multiples structures de l’ADN quadruplex via i) le développement et l’utilisation d’un test haut-débit pour l’analyse des interactions ligand-ADN quadruplex et le criblage de chimiothèques/ciblothèques et ii) la préparation de composés aux modes d’interactions multiples (empilement/sillon, covalent/non-covalent, etc.), sélectifs (quadruplex vs. duplex et intra-quadruplex) et éventuellement fonctionnalisés (biotine, fluorophore, etc.). La première partie des travaux a été centrée sur le développement du test G4-FID (G-quadruplex Fluorescent Intercalator Displacement) qui est une méthode semi-quantitative permettant l’évaluation de l’affinité et de la sélectivité de petites molécules pour l’ADN quadruplex par déplacement d’une sonde off/on, le Thiazole Orange (TO). Le test a notamment été transposé avec succès de la cuve vers la microplaque (HT-G4-FID). D’autre part, nous avons montré l’intérêt de fluorophores alternatifs, TO-PRO-3 et Hoechst 33258, aux caractéristiques spectrales complémentaires à TO. Cette méthode d’analyse a également été utilisée avec succès pour l’identification de nouveaux ligands sélectifs d’ADN quadruplex et la mise en évidence des relations structure-activité ainsi que des sélectivités structurales. La deuxième partie des travaux a été consacrée à la préparation et à l’étude de nouveaux ligands d’ADN quadruplex. Ces ligands possèdent des particularités, soit dans leur mode d’interaction (sillons, coordination) soit par leur bifonctionnalité (biotinylés, fluorescents). Nous avons ainsi préparé un ligand de quadruplex polyhétéroaryle acyclique (TOxaPy) possédant une sélectivité inattendue pour certaines structures de l’ADN quadruplex. D’autre part, nous avons montré que les complexes de dérivés de terpyridine peuvent être adaptés, en changeant le ligand organique et/ou la nature du métal, de façon à interagir avec l’ADN quadruplex par interaction covalentes et/ou non covalentes. / The aim of this thesis work was to study the interactions of small molecules with multiple structures of quadruplex DNA via i) the development and use of a high-throughput test for the analysis of ligand-quadruplex DNA interactions and screening of chemical libraries and ii) the preparation of compounds with multiple binding modes (stacking/groove, covalent/non-covalent, etc..) selective (quadruplex vs. duplex and intra-quadruplex) and possibly functionalized (biotin, fluorophore, etc.). The first part of the work was focused on the development of the G4-FID (G-quadruplex Intercalator Fluorescent Displacement) assay, which is a semi-quantitative method for evaluating the affinity and selectivity of small molecules for quadruplex DNA by displacing an off/on probe, the Thiazole Orange (TO). The test has been implemented successfully with microplate (HT-G4-FID). On the other hand, we have shown the importance of alternative fluorophores, TO-PRO-3 and Hoechst 33258, with complementary spectral characteristics. This method of analysis has also been successfully used for the identification of new selective ligands of quadruplex DNA and the identification of structure-activity relationships and structural selectivities. The second part of the work was devoted to the preparation and study of new DNA quadruplex ligands. These ligands possess particular characteristics either in their mode of interaction (grooves, coordination) or by their bifunctionality (biotinylated, fluorescent). We have prepared an acyclic polyheteroaryle quadruplex ligand (TOxaPy) with an unexpected selectivity for certain structures of quadruplex DNA. Furthermore, we showed that complexes of terpyridine derivatives can be tailored by changing the organic ligand and / or the metal in order to interact with quadruplex DNA by covalent and / or non-covalent interaction.