Dissertations / Theses on the topic 'Paper chromatography'

Orientador: Lauro Tatsuo Kubota
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: Este trabalho apresenta o esforço dispendido na construção e caracterização de transdutores eletroquímicos sobre poliéster e papel, e também demonstra o emprego destas células eletroquímicas descartáveis no desenvolvimento de um biossensor para análises rápidas de salicilato em sangue, bem como a criação de um dispositivo de separação associado à detecção eletroquímica em papel. Cada célula eletroquímica é composta por um conjunto de três eletrodos de filmes finos construídos em ouro sobre poliéster ou papel cromatográfico por meio das técnicas de sputtering e electron-beam, respectivamente. Foi realizada a caracterização voltamétrica dos sistemas eletródicos empregando sondas redox como hexacianoferrato(II) de potássio, hexacianoferrato(III) de potássio e ácido ferrocenomonocarboxílico em meio eletrolítico, a fim de verificar a eletroatividade dos mesmos. Foi possível verificar que mesmo apresentando maior área eletroativa, os eletrodos de filmes finos construídos sobre papel apresentam uma menor densidade de corrente para as sondas redox em comparação com a célula eletroquímica construída em poliéster. Isto se deve à retenção das espécies eletroativas na fibra de celulose, fato que diminui a disponibilidade da espécie na superfície eletródica. Foi desenvolvido um biossensor amperométrico para a determinação de salicilato em sangue. O biossensor se baseia no emprego da enzima Salicilato hidroxilase imobilizada sobre a célula eletroquímica plástica. As condições experimentais otimizadas consistem em utilizar uma solução eletrolítica de tampão fosfato em pH 7,6 com 0,5 mmol L de NADH e 300 mV vs. Au como potencial aplicado durante as medidas. O biossensor apresentou adequada sensibilidade (97,4 nA/mmol L de salicilato) e faixa linear de resposta para o analito (1,25 10 to 1,0 10 mol L). O desempenho do biossensor foi verificado na determinação de salicilato em amostras de sangue dopadas com o analito e os resultados foram estatisticamente equivalentes àqueles obtidos com o método espectrofotométrico de Trinder em um nível de confiança de 95%. O dispositivo de separação cromatográfica em papel associado à detecção eletroquímica foi desenvolvido empregando a célula eletroquímica plástica e a célula eletroquímica sobre papel. O desempenho dos dispositivos foi avaliado na separação e quantificação de ácido úrico e áscórbico presentes em mistura. O método desenvolvido é uma alternativa para a determinação de compostos eletroativos em que o baixo custo e a simplicidade são essenciais
Abstract: This paper presents the efforts to the construction and characterization of electrochemical transducers on polyester and paper, and also demonstrates the use of these disposable electrochemical cells in the development of a biosensor for rapid analysis of salicylate in blood as well as the creation of a separation device associated electrochemical detection on paper. Each electrochemical cell consists of a set of three electrodes made of gold thin films on polyester or chromatographic paper using sputtering and electron-beam techniques, respectively. The electrochemical characterization of the systems with redox probes as potassium hexacyanoferrate(II), potassium hexacyanoferrate(III) and ferrocene monocarboxylic acid was performed in the electrolyte solution in order to evaluate the electroactivity of them. It was verified that even with higher electroactive area, the electrodes of thin films built on paper have a lower current density for the redox probes in comparison with the electrochemical cell constructed on polyester. This is due to retention of electroactive species in the cellulose fiber, a fact that reduces the availability of those species on the transducer surface. We developed an amperometric biosensor for the determination of salicylate in blood. The biosensor is based on the use of the salicylate hydroxylase enzyme immobilized on plastic electrochemical cell. The determined optimized experimental conditions are: an electrolyte solution of phosphate buffer at pH 7.6 with 0.5 mmol L of NADH and 300 mV vs. Au as the applied potential during the measurements. The biosensor showed adequate sensitivity (97.4 nA / mmol L salicylate) and linear response range for the analyte (1.25 10 to 1.0 10 mol L). The performance of the biosensor was found in the determination of salicylate in blood samples spiked with the analyte and the results were statistically equivalent to those obtained with the Trinder¿s spectrophotometric method, with a 95% confidence level. Prototypes of microfluidic paper-based separation devices with amperometric detection were developed and evaluated. The chromatographic separation on paper associated with electrochemical detection was developed using the plastic electrochemical cell and the gold electrochemical cell on paper. The performance of both devices was evaluated for separation and quantification of uric acid and ascorbic acid presented in the mixtures. The method is an alternative for the determination of electroactive compounds when low cost and simplicity are essential
Doutorado
Quimica Analitica
Doutor em Ciências

Pyrolysis-capillary gas chromatography combined with FID, ECD and MS detection were used to characterize refuse-derived fuel and aquatic fulvic acids. Different pyrolysis methods and programs were evaluated. Pyrolysis temperatures of 700-800°C produced the strongest signal for organics present in RDF and fulvic acid. Cellulose and fatty acids pyrolyzates were identifiable by GC-MS following preparative pyrolysis fractionation. At organic chloride content of 0.023%, only three halogenated compounds were detected in the GC-MS of the fractions. None of the priority pollutants were detected at lower detection limit of 0.72 to 24 mg/ kg RDF. Selective solvent extraction improves the reproduciblities of the technique and allows the detection of polymeric structures. Pyrograms of polyvinyl chloride and regular typing paper showed some common peaks that are present in the RDF pyrogram. About 65% of the peaks in the RDF pyrogram might be of paper origin. The organic chloride content of the RDF was evaluated by ion chromatography of the trapped pyrolyzates in 2% NaOH trap and it was found to be 221 mg Cl/ kg dry RDF. Pyrolysis conditions and temperature programs for FA were systematically evaluated. Samples included purified FA, methylated FA and HPLC separated fractions. Characteristic pyrograms were developed. Profiles of benzene, toluene, phenol, m-cresol and biphenyl from FA were evaluated. The production of phenol was the largest at 800°C, at concentration of 1.61 mg per gram of FA pyrolyzed. The profiles of benzene and toluene followed the same pathways. Both pyrolyzates had at least two precursors. HPLC fractions of FA showed some regular retention patterns characteristic of polymeric material. DL-proline, seriene and vanillic acid pyrograms showed some peaks with the same retention times as those in FA pyrogram under the same conditions. A reproducibility of 6% relative standard deviation was achieved in the pyrolysis of RDF and 0.91% in the case of FA.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
FAPESP:05/58301-0

The objective of this study was to gain a better understanding of Opal Australian Paper’s (AP’s) waste streams as a potential substrate for biomanufacturing. Three low-value process streams were included in this study: Continuous Kraft Mill (CKM) weak black liquor (WBL), Neutral Sulphite Semi-Chemical (NSSC) WBL and WBL extracted from NSSC clean-pulp (CP). The primary focus of the study was to determine the chemical composition and extent of toxicity of these WBLs towards Actinobacillus succinogenes 130Z. This genetically engineered bacterium can produce a valuable platform chemical, succinic acid, using various carbohydrate sources. This project sought to increase knowledge of AP’s WBL and its suitability as a biomanufacturing substrate. Literature has been reviewed on various pre-treatment pathways for this waste stream, A. succinogenes 130Z and its effectiveness on producing succinic acid, and the analytical techniques that have been used to answer the project objectives. The effectiveness of pre-treating the NSSC and CP WBLs was measured using the following characteristics: (a) the colour content (specific absorbance) using UV-Vis spectroscopy, (b) indicative yields of several organic constituents through pyrolysis-gas chromatography-mass spectroscopy, (c) the atomic H/C and S/C ratios using an elemental analysis and (d) toxicity of the samples using a combination of semi-quantitative (plating trials) and quantitative (determination of minimum bactericidal concentration) techniques. The impact of an additional pre-treatment step of granular activated carbon for NSSC WBL was also researched here. InfraRed spectroscopy and toxicity analysis helped to conclude that CKM WBL is extremely toxic to Actinobacillus succinogenes 130Z and contained negligible amounts of residual sugar units. Characterising the NSSC and CP WBLs at the molecular level revealed the untreated WBLs are rich in lignin-derived methoxyphenols (up to 160 mg/kg) and contained low concentrations of elemental sulphur (up to approx. 1 mg/kg). Infra-red spectroscopy and gas chromatography indicated that the fermentable sugars in the WBLs were very low (< 1.2 mg/kg) even after pre-treatment. Both methoxyphenols and sulphur are known to be toxic to many bacteria and A. succinogenes 130Z could not tolerate more than 0.45 mg/ml (db, dry basis) and 0.78 mg/ml (db) of NSSC and CP WBLs respectively. Employing Amberlite® XAD7HP resins to pre-treat the NSSC and CP WBLs reduced their toxicity 2- to 5-fold, enabling the bacterium to survive in about 2.5 mg/ml (db) and 1 mg/ml (db) of NSSC and CP WBLs respectively. One possible reason for this is the significant reduction in lignin content afforded by this pre-treatment technique. These results conclude that AP’s WBLs are toxic and need to undergo pre-treatment prior to utilisation as a substrate for succinic acid production via fermentation.
Master by Research

The objective of this study was to gain a better understanding of Opal Australian Paper’s (AP’s) waste streams as a potential substrate for biomanufacturing. Three low-value process streams were included in this study: Continuous Kraft Mill (CKM) weak black liquor (WBL), Neutral Sulphite Semi-Chemical (NSSC) WBL and WBL extracted from NSSC clean-pulp (CP). The primary focus of the study was to determine the chemical composition and extent of toxicity of these WBLs towards Actinobacillus succinogenes 130Z. This genetically engineered bacterium can produce a valuable platform chemical, succinic acid, using various carbohydrate sources. This project sought to increase knowledge of AP’s WBL and its suitability as a biomanufacturing substrate. Literature has been reviewed on various pre-treatment pathways for this waste stream, A. succinogenes 130Z and its effectiveness on producing succinic acid, and the analytical techniques that have been used to answer the project objectives. The effectiveness of pre-treating the NSSC and CP WBLs was measured using the following characteristics: (a) the colour content (specific absorbance) using UV-Vis spectroscopy, (b) indicative yields of several organic constituents through pyrolysis-gas chromatography-mass spectroscopy, (c) the atomic H/C and S/C ratios using an elemental analysis and (d) toxicity of the samples using a combination of semi-quantitative (plating trials) and quantitative (determination of minimum bactericidal concentration) techniques. The impact of an additional pre-treatment step of granular activated carbon for NSSC WBL was also researched here. InfraRed spectroscopy and toxicity analysis helped to conclude that CKM WBL is extremely toxic to Actinobacillus succinogenes 130Z and contained negligible amounts of residual sugar units. Characterising the NSSC and CP WBLs at the molecular level revealed the untreated WBLs are rich in lignin-derived methoxyphenols (up to 160 mg/kg) and contained low concentrations of elemental sulphur (up to approx. 1 mg/kg). Infra-red spectroscopy and gas chromatography indicated that the fermentable sugars in the WBLs were very low (< 1.2 mg/kg) even after pre-treatment. Both methoxyphenols and sulphur are known to be toxic to many bacteria and A. succinogenes 130Z could not tolerate more than 0.45 mg/ml (db, dry basis) and 0.78 mg/ml (db) of NSSC and CP WBLs respectively. Employing Amberlite® XAD7HP resins to pre-treat the NSSC and CP WBLs reduced their toxicity 2- to 5-fold, enabling the bacterium to survive in about 2.5 mg/ml (db) and 1 mg/ml (db) of NSSC and CP WBLs respectively. One possible reason for this is the significant reduction in lignin content afforded by this pre-treatment technique. These results conclude that AP’s WBLs are toxic and need to undergo pre-treatment prior to utilisation as a substrate for succinic acid production via fermentation.
Masters by Research

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The objectives of the study were: a) evaluate the equipment and aerial application rates to maximizing the coverage and penetration of fungicides drops in the canopy leaf through Water-sensitive paper and chromatography b) measure the spectra of droplets generated by hydraulic nozzles, nozzles electrostatic and rotating atomisers disk c) evaluate the yield components: seed yield and ingenuity income d) evaluate the control of Cercospora oryzae in accordance with the devices tested. For the deposition of drops in three tiers with Water-sensitive papers review, the hydraulic nozzle equipment with 30 L.ha-1 had higher deposition in the upper third and medium. For the bottom third, the rotary atomizer disks in the rate of 15 L.ha-1 had higher penetration. With chromatography, the largest amount of product in the lower canopy was achieved through the electrostatic equipment with 10 L.ha-1. For the control of Cercospora oryzae the data were not consistent, because the treatments did not differ from the witness. For weight and grain yield there was no difference among treatments. For ingenuity income, the weight of grain was obtained using the hydraulic equipment Nozzle 20L.ha-1. The penetration and density were evaluated in relation to rates and equipment through contrasts. Most treatments showed differences between the equipment and rates.
Os objetivos dos trabalhos foram: a) Avaliar equipamentos de aplicação aérea e taxas de aplicação para maximização da cobertura e penetração de gotas de fungicidas no dossel foliar através de papel hidrossensível e cromatografia; b) avaliar os espectros de gotas gerados por bicos hidráulicos, bicos eletrostáticos e atomizadores rotativos de disco; c) avaliar os componentes de rendimento: produtividade de grãos e rendimento de engenho; e d) avaliar o controle de Cercospora oryzae. Para condução do experimento foi utilizado 8 tratamentos divididos em 63 ha. Em cada área foi avaliada a cobertura e penetração através de papeis hidrossensiveis e análise cromatográfica. A deposição de gotas em três estratos com análise de papéis hidrossensíveis, o equipamento bico hidráulico com 30 L.ha-1 teve maior deposição no terço superior e médio. Para o terço inferior, o atomizador rotativo de discos na taxa de 15 L.ha-1 apresentou maior penetração. Com cromatografia, a maior quantidade de produto no estrato inferior foi conseguida através do equipamento Eletrostático com 10 L.ha-1. Para o controle de Cercospora oryzae, os dados não foram consistentes, pois os tratamentos não diferiram da testemunha. Não houve diferenças para peso de grãos e produtividade entre os tratamentos. No rendimento de engenho, o maior peso de grão inteiro foi obtido com a utilização do equipamento Bico hidráulico 20L.ha-1. A densidade e a penetração foram avaliadas em relação às taxas e aos equipamentos, através de contrastes. A maioria dos tratamentos evidenciou diferenças entre os equipamentos e as taxas.

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CAPES
No presente trabalho, desenvolveu-se um método alternativo para determinação de cobre, ferro, níquel e zinco, usando a espectrometria de fluorescência de raios-X com energia dispersiva (EDXRF), em amostras de etanol combustível e cachaça, após procedimento de pré-concentração. O procedimento consistiu na retenção dos analitos em papel cromatográfico de troca iônica, suporte sólido que se mostrou apropriado para medições diretas por EDXRF. Algumas variáveis foram otimizadas e os melhores resultados obtidos foram: vazão de amostragem de 2,0 mL min-1, pH entre 5,0 e 7,5 e volume de amostragem de 10 mL. No procedimento, com auxílio de uma bomba peristáltica, alíquotas da solução padrão ou amostra foram passadas em papel cromatográfico de troca catiônica, que foi cortado em círculos com 13 mm de diâmetro e adaptados em suporte para filtração. Após a secagem dos papéis cromatográficos, foram realizadas medições diretas no papel empregando espectrômetro de fluorescência de raios-x de energia dispersiva. As curvas de calibração apresentaram resposta linear no intervalo de 0,050 a 1,50 μg mL-1 dos analitos. As repetibilidades, expressas em termos de RSD das soluções-padrão contendo 0,25 μg mL-1 de Cu, Fe, Ni e Zn, calculadas a partir de 15 determinações consecutivas, foram de 2,5, 2,8, 3,0 e 2,7%; e 3,1, 2,9, 2,8 e 2,7%, para matrizes com 96% e 50% de etanol, respectivamente. Obteve-se limites de quantificação (LQ) iguais a 43, 50, 50 e 40; e 47, 54, 59 e 45 μg mL-1, para matrizes com 96% e 50% de etanol, respectivamente. O procedimento foi verificado através de testes de recuperação, adicionando-se 100 μg L-1 de cada metal nas diferentes amostras, com resultados entre 92 e 99%. Os resultados obtidos pelo método proposto foram comparados com os resultados obtidos por um método comparativo usando ICP OES, após digestão das amostras, não apresentando diferenças significativas, com um nível de confiança de 95%. O método proposto é simples e não exigiu que as amostras fossem submetidas a qualquer pré-tratamento drástico ou demorado.
Salvador

This thesis describes bioanalytical methods for measuring melatonin and some anti-infective drugs in biological fluids. Solid-phase extraction (SPE) or protein precipitation was used for enrichment and purification of the analytes and Liquid Chromatography (LC) was used to analyze the samples. Developed methods were validated according to international guidelines. Melatonin is a hormone secreted by the pineal gland with a robust circadian rhythm. Bioanalytical methods for determination of melatonin in plasma and saliva have been developed which were used for monitoring melatonin levels in volunteers and patients suffering from sleep related diseases. Eflornithine (DFMO) is a chiral drug used for the treatment of human African trypanosomiasis. A bioanalytical method for determination of the DFMO enantiomers in plasma, after precolumn derivatization with o-phtalaldehyde and N-acetyl-L-cystein has been developed. The method has been used to study the L- and D-DFMO pharmacokinetics, in order to investigate the possible development of an oral treatment of DFMO. A method for simultaneous determination of three antiretroviral drugs i.e. Lamivudine (3TC), Zidovudine (AZT) and Nevirapine (NVP) in dried blood spots (DBS) was developed. The method was used for drug determination in two subjects after receiving standard antiretroviral treatment. The method seemed well suitable for the determination of 3TC and NVP and in some extent for AZT. Lumefantrine (LF) is one of the active components in a new fixed drug combination recommended by the WHO as a replacement to older drugs that has lost their effect. A method for the determination of LF in DBS was developed. The method is suitable for monitoring of drug treatment in rural settings. Tafenoquine is a new promising antimalarial drug under development. A method for the determination of Tafenoquine in plasma and in DBS is described. The method may be useful in future clinical studies in laboratory environment as well as in rural settings.
Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 703

Cette thèse a été conduite afin d’explorer le potentiel d’une nouvelle méthodologie utilisant la pyrolyse, la chromatographie gazeuse et la spectrométrie de masse pour la caractérisation et l’identification des fibres papetières utilisées dans la fabrication des papiers asiatiques traditionnels à partir de la caractérisation des métabolites de ces fibres. Cette méthodologie utilise un processus d’échantillonnage facilité nécessitant une très petite quantité d’échantillons (de l’ordre de quelques dizaines de µg). Après la pyrolyse des échantillons de papiers et la séparation chromatographique des composés formés, des distributions caractéristiques pour les métabolites des fibres papetières (considérant leur présence et leur intensité) ont été observées dans une région définie comme région d’intérêt dans les chromatogrammes: ces distributions se sont révélées spécifiques pour la caractérisation des papiers fabriqués à partir de différents types de fibres et ont été utilisées pour distinguer l’origine des différentes fibres papetières couramment utilisées dans la fabrication de papiers asiatiques traditionnels. Premièrement, les problèmes rencontrés dans l’étude des papiers faits à la main ont été présentés, comme l’origine de la fabrication du papier, l’incohérence de certains résultats dans l’identification des fibres (reportés dans différentes études scientifiques), les limites de la microscopie pour l’identification des fibres papetières d’origines botaniques similaires et les risques d’imprécision dans le référencement des échantillons. Tous ces problèmes montrent la nécessité d’explorer de nouvelles méthodes pour (1) améliorer la fiabilité de l’identification des fibres papetières des papiers asiatiques traditionnels, (2) valider et confirmer les résultats obtenus par l’analyse microscopique. À cette fin, dans un premier temps, des papiers asiatiques de référence ont été étudiés. Les résultats expérimentaux ont montré que les différentes fibres papetières utilisées pour la fabrication des papiers étudiés montraient des différences dans les distributions de leurs marqueurs spécifiques : par exemple, les fibres d’origine de la famille Moraceae montrent une distribution caractéristiques de composés triterpèniques alors que les fibres d’origine de la famille Thymelaeaceae montrent une distribution caractéristiques de composés de type stigmastanes. De leur côté, les fibres des plantes appartenant au groupe Ma montrent peu de métabolites caractéristiques. Les différences observées dans la distribution de ces métabolites ont été attestées par la comparaison entre distributions obtenues à partir des fibres végétales et celles des papiers faits à la main attestant de l’origine commune de ces métabolites issus des tissus végétaux d’origine. Ainsi, la méthodologie étudiée se révèle prometteuse en tant que méthode de chimiotaxonomie pour l’identification des fibres inconnues de papiers faits à la main. Avec les exemples d'applications fournies au cours du travail expérimental, le couplage de la pyrolyse, de la chromatographie en phase gazeuse et de la spectrométrie de masse (avec l’utilisation de la Py-GC/MS et de la Py-GCxGC/MS) a montré sa capacité à distinguer les fibres d'une même famille (qui peuvent présenter des caractéristiques similaires en microscopie) et peut ainsi constituer une méthode efficace d'identification des fibres et de validation des résultats d'identification obtenus par l'observation microscopique. Dans la présente thèse, les caractéristiques de la chromatographie gazeuse intégralement bidimensionnelle GCxGC, ses avantages pour les applications dans le domaine du patrimoine culturel et son apport potentiel pour le traitement des données 1D ont été discutées (...)
This study was conducted to explore a new methodology for handmade fiber characterizationand identification using pyrolysis, gas chromatography and mass spectrometry. It employseasy sampling process with minor quantity of samples required. After pyrolysis of handmadepapers, a featured metabolites distribution patterns (presence plus intensity) eluting in the defined region of interest (ROI) was observed to be characteristic for handmade papers of different material origins. The method utilizes these metabolites distribution patterns as markers to discriminate different fiber origins. Firstly, the problems encountered in the investigation of handmade papers were introduced such as the origin of papermaking, the inconsistency in the fiber identification results sometimes gained by different scholars, the limits of microscopy in identifying fibers from similar species and the likely imprecision of the reference sample labeling. All these problems showed the necessity to explore a new method in order to (i) make precise fiber identification of handmade papers and (ii) to validate or confirm the identification results obtained by microscopy. Then, modern reference handmade papers were firstly studied. The result revealed that different plant fibers used for papermaking have different marker distributions in the ROI, forinstance, the Moraceae family with a featured distribution of terpene compounds and theThymelaeaceae family with a featured distribution of stigmasta compounds. The fibers fromthe ma group usually revealed few compounds in the ROI. This metabolites difference in theROI was attested from the plant tissues with their similar distribution in handmade papers and plant raw fibers. Thus, the chosen methodology offers promise as a method of chemotaxonomy for unknown handmade paper fiber identification. With the examples ofapplications provided during the experimental work, the coupling of pyrolysis, gaschromatography and mass spectrometry (through the use of Py-GC/MS and Py-GCxGC/MS)showed its ability to distinguish fibers from the same plant family (that may present similar microscopic features) and thus, can constitutes an effective method for fiber identification as well as to validate the identification results of the microscopic observation. In the present thesis, the features of GCxGC and the benefits for cultural heritage applications and its help for the ID data treatment were discussed. The tested Py-GCxGC/MS methodology has been for the first time proposed in the cultural heritage field and it harbors the potential to promote the research in this domain, enhancing our capacity to handle small quantities of complex samples while providing an exhaustive response on its composition

De nombeux documents graphiques dans les archives, bibliothèques et caninets d'arts graphiques ont été fragilisés par des conditions de conservation inadéquates ou des constituants de mauvaise qualité. Il est toutefois difficile d'évaluer visuellement le degré d'altération de ces oeuvres et les méthodes traditionnelles sont trop destructrices pour pouvoir être appliquées. L'objet de cette étude est l'évaluation de l'état d'altération de documents historiques par la méthode micro-destructive de chromatographie d'exclusion stérique (CES). Nous avons tout d'abord développé un protocole pour la préparation des échantillons destinés à être analysés en CES. Ensuite, en appliquant divers vieillissements artificiels, nous avons suivi l'évolution de la distribution des masses moléculaires (MMD) de la cellulose/holocellulose de différents types de papiers. Nous avons pu identifier des modifications importantes et des différences notables au niveau de l'évolution des MMD selon le type des fibres. Nos résultats indiquent que la CES permet de mettre en évidence les altérations subies par la cellulose déjà dès les premiers stades, alors que pour ces stades aucune fragilisation n'est observée en appliquant les essais mécaniques traditionnels (zéro-span, résistance à la traction). La relation entre des propriétés mécaniques du papier et la MMD de la cellulose, au cours du vieillissement, est essentiellement liée à la nature des fibres, alors que le type d'agression ne joue qu'un rôle secondaire : quelque soit la nature du vieillissement, on observe la même corrélation entre l'évolution des MMD et les propriétés physiques du papier. Les rapports entre résistance et masse moléculaire de tous les papiers tendent vers un comportement commun quand la dégradation progresse. Cela nous a permis de définir une "valeur critique", à partir de la distribution des masses moléculaires, valeur à partir de laquelle le papier peut être considéré comme très fragile

Dans le cadre d’une valorisation non alimentaire du Blé en Champagne-Ardenne, les glycérides issus du gluten ont été étudiés en tant qu’inhibiteurs des protéinases neutres impliquées dans le vieillissement cutané (plasmine, MMP-1, MMP-2 et MMP-3). Cette étude a pour but de fractionner l’huile, puis d’isoler et de caractériser chimiquement les glycoglycérolipides, molécules d’intérêts. La stratégie de fractionnement retenue utilise principalement des techniques de partage liquide/liquide. Les étapes d’extraction liquide/liquide visant à obtenir une fraction enrichie en composés d’intérêts ont été effectuées avec un souci de transposabilité industrielle. La fraction enrichie a ensuite été soumise à des étapes de chromatographies en mode partage faisant principalement appel à la chromatographie de partage centrifuge (CPC), permettant de fournir des fractions chimiquement simplifiées et exploitables en biologie. La mise au point des systèmes biphasiques de solvants a nécessité une approche méthodologique afin d’optimiser la sélectivité et les phénomènes de transfert de matière. L’outil d’évaluation de ces systèmes développé ensuite, a permis de sélectionner ceux appropriés au screening des composés de l’extrait. Les tests d’activités biologiques concluants vis-à-vis de certaines des cibles visées, nous ont amené à poursuivre l’isolement des composés glycoglycérolipidiques dans le but d’amorcer les études de relation structure/activité (RMN, Masse,. . ). Enfin, nous avons développé un nouveau mode chromatographique semi-continu en CPC (multiple dual mode : MDM), afin de résoudre les problèmes de co-élution rencontrés lors de l’isolement de composés de très proches parenté structurale
@This work concerns non-food valorisation of Champagne-Ardenne agricultural resources in the field of dermo-cosmetic applications. Wheat gluten, used as starting material, contains glycérides – the molecules of interest – that have shown inhibiting effect on MMP-1 and MMP-3 (neutral proteinases implied in cutaneous ageing). The fractionation process strategy is mainly based on liquide/liquide partition in order to avoid artefact generation or degradation of the analytes often encountered with adsorption phenomena on solid support. The extraction process leading to an enriched glycoglycerolipid extract (solide liquide and liquide/liquid steps) was designed under industrial constraints in order to allow scale-up procedures. This extract was then fractionated using partition chromatographic techniques as Centrifugal Partition Chromatography (CPC), in order to establish structure-activity relationships. Pure isolated compounds were submitted to structural elucidation techniques (NMR, mass ,…). Moreover, this approach leads us to develop a simple CPC chemical screening methodology integrating selectivity and polarity criterions. Finally, we developed a semi-continuous chromatographic mode in CPC (multiple dual mode: MDM), in order to resolved co-elution problems often encountered with structurally similar molecular analytes like homologues natural compounds

Le remplacement progressif des transformateurs de puissance est actuellement teste dans differents pays. Cette situation rend importante la composante economique des processus de vieillissement et la notion de duree de vie. La prediction de la duree de vie des materiaux tel que le papier de guipage est plus complexe que la caracterisation d'un defaut precis. De maniere pratique, nous sommes amenes a considerer qu'un mecanisme de degradation connu est continuellement present dans l'ensemble de la gamme de temperature etudiee. L'hydrolyse, l'oxydation et la pyrolyse sont les differents mecanismes de degradation du papier que nous avons considere, d'apres les connaissances actuelles. Partant de ces considerations, six transformateurs ferrailles (en defaut ou vetuste) ont ete soigneusement examines. Ces transformateurs ont permis la mise du point de techniques que nous avons ensuite utilisees pour l'etude de maquettes de vieillissement ou la temperature et l'eau etaient les facteurs de degradation consideres. Les techniques utilisees (chromatographie liquide haute performance, chromatographie en phase gazeuse couplee a la spectrometrie de masse) ont permis de caracteriser des traceurs de vieillissement, dans l'huile et le papier de guipage. Des essais de correlation ont ete menes a partir des resultats obtenus

Doutoramento em Engenharia Química
A exploração de compostos, subprodutos e resíduos naturais é um passo chave para a obtenção de um futuro sustentável. A valorização e comercialização destes materiais dependem da aplicação de técnicas adequadas de conversão e separação/purificação que permitam obter os níveis desejados de pureza e produtividade. Os ácidos triterpénicos, particularmente os ácidos betulínico, oleanólico e ursólico, são compostos de elevado valor que têm atraído interesse devido às suas já reportadas propriedades nutraceuticas e farmacológicas. Estes triterpenoides estão presentes em diversas fontes vegetais mas podem ser encontrados com abundâncias consideráveis na casca do eucalipto (decídua e externa), um resíduo comum da indústria da pasta e papel. O isolamento dos ácidos triterpénicos é uma tarefa difícil devido às suas semelhantes estruturas moleculares, especialmente no caso dos ácidos oleanólico e ursólico, que são isómeros de posição. O leito móvel simulado (simulated moving bed, SMB) é uma técnica cromatográfica de separação contínua e em contracorrente que maximiza a força diretriz de transferência de massa permitindo a separação de moléculas mesmo quando as seletividades se aproximam de um. Por exemplo, é frequentemente utilizada no isolamento de enantiómeros. No SMB clássico a separação de dois componentes é efetuada em quatro zonas, os caudais e concentrações de alimentação são fixos e as portas de entrada/saída são comutadas simultaneamente. Recentemente, novas implementações tais como a modificação da concentração ou caudais da alimentação, a utilização de tempos de comutação variáveis e a introdução de novas zonas para separação multicomponente, têm permitido a obtenção de maior flexibilidade e melhor performance. Uma revisão profunda destes modos de operação foi feita durante esta tese. A modelação e otimização são passos essenciais no dimensionamento e desenvolvimento de qualquer processo e particularmente importantes no SMB. Como ponto de partida para o estudo do fracionamento de ácidos triterpénicos por leito móvel simulado, modelos fenomenológicos conhecidos foram aplicados para desenvolver de um simulador SMB. Durante este trabalho uma estratégia de otimização de unidades de SMB foi desenvolvida combinando as metodologias de desenho de experiências e respostas de superfície com simulações computacionais, com o objetivo de obter condições de operação ótimas com baixa complexidade e um esforço computacional reduzido. Esta técnica de otimização foi aplicada ao estudo da separação dos enantiómeros de óxido de trans-estilbeno, usando informação da literatura, e posteriormente comparada com outros procedimentos de determinação de condições de operação ótimas. Esta técnica permitiu purezas acima de 99.5 % para ambos enantiómeros, necessitando de um baixo número de simulações. A separação de ácidos triterpénicos foi inicialmente estudada à escala analítica, através de uma série de ensaios cromatográficos em diferentes condições para seleção de fase móvel e estacionária apropriada. Os melhores resultados foram obtidos com uma coluna Apollo C18 usando metanol/água 95/5 (%,v/v) e os parâmetros de equilíbrio e transporte foram determinados através de experiências de rutura com os compostos puros. Esta informação foi utilizada com sucesso na simulação da separação de uma mistura ternária, cujos resultados foram validados com experiências de rutura ternárias. A separação em SMB de uma mistura representativa de um extrato natural contendo os ácidos betulínico, oleanólico e ursólico foi desenhada utilizando um processo em dois passos: inicialmente o ácido betulínico foi isolado dos ácidos oleanólico e ursólico e, de seguida, os ácidos oleanólico e ursólico foram fracionados. Esta separação foi otimizada usando a metodologia de desenho de experiências e respostas de superfície combinada com simulações rigorosas e permitiu demonstrar que é possível produzir os ácidos betulínico, oleanólico e ursólico com purezas de 99.4 %, 99.1 %, e 99.4 %. Os polímeros molecularmente impressos (molecularly imprinted polymers, MIPs) são sintetizados para possuírem centros ativos altamente seletivos para moléculas alvo, tornando-os adsorventes muito promissores. Vários MIPs foram sintetizados por polimerização por precipitação usando diferentes formulações. Após a preparação, estes polímeros foram caracterizados por microscopia eletrónica de varrimento e os mais promissores, em termos de características morfológicas, foram diretamente testados através de experiências de adsorção. Os resultados revelam que o material “MIP1b” exibe selectividade infinita para o ácido oleanólico, a molécula alvo usada na sua síntese. Em conjunto com a sua capacidade de adsorção – superior à da previamente estudada fase C18 – estes resultados demonstram o elevado potencial do polímero “MIP1b” para aplicação na separação dos ácidos triterpénicos. Investigação adicional é necessária neste tópico onde diferentes técnicas de separação podem ser antecipadas. Este trabalho culminou com o dimensionamento e montagem de uma unidade laboratorial de leito móvel verdadeiro baseada num sistema de uma-válvula-ST por coluna recentemente patenteado, que permite à unidade operar sobre diferentes estratégias de operação e configurações.
The exploitation of natural compounds, by-products and residues is a key strategy for the pursuit of a sustainable future. The effective valorization and commercialization of these materials depends on the application of adequate conversion and separation/purification techniques that can provide desired levels of purity and productivity. Triterpenic acids, particularly betulinic, oleanolic, and ursolic acids, are high value molecules that have attracted considerable interest due to their reported nutraceutical and pharmacological properties. These triterpenoids are present in diverse vegetable sources but significant abundances are found in Eucalyptus bark (deciduous and external), a common residue from the paper and pulp industry. The isolation of triterpenic acids is a difficult task due to their similar molecular structures, particularly in the case of oleanolic and ursolic acids, which are positional isomers. The simulated moving bed (SMB) technology is a countercurrent continuous chromatographic technique that maximizes the mass transfer driving force, thus allowing the separation of compounds even when selectivities approach one. For instance, it is often used for enantiomers isolation. In a classic SMB, the separation of two components is accomplished across four zones, the flow rates and feed concentrations are fixed, and the inlet/outlet ports are switched synchronously. Recently, new implementations and modifications, such as the modulation of feed concentration or flow rates, variable switch times and additional zones for multicomponent separations, enabled better flexibility and performances to be achieved. A thorough review of these modes of operation was performed in this thesis. Modeling and optimization are necessary steps for the design and development of any process, being particularly important in SMB. As the starting point for the study of the fractionation of triterpenic acids by simulated moving bed, well know phenomenological models were applied to develop a SMB simulator. During this work, an optimization strategy of SMB units was developed combining the design of experiments and response surface methodologies (DoE-RSM) with computer simulations, aimed at providing good operating conditions with low complexity and reduced computational effort. This optimization technique was applied to the separation of trans-stilbene oxide (TSO) enantiomers using data from the literature and compared with other existing procedures for the determination of the best operation conditions. It allowed purities above 99.5 % for both TSO enantiomers while requiring a small number of simulations. The separation of triterpenic acids was initially studied at analytical scale, through a series of chromatographic assays under different conditions, to select appropriate mobile and stationary phases. Best results were obtained using an Apollo C18 column and methanol/water 95/5 (%, v/v), and equilibrium and mass transport parameters were determined through breakthrough experiments with pure compounds. This information was then successfully applied in the simulation of a ternary mixture separation, whose results were validated with ternary breakthrough measurements. The SMB separation of a representative natural extract containing betulinic, oleanolic and ursolic acids was designed using a two-step process: firstly, betulinic acid was isolated from oleanolic and ursolic acids, and secondly, oleanolic and ursolic acids were fractionated. This separation approach was optimized using DoE-RSM combined with rigorous simulations, and it was demonstrated that it is possible to produce betulinic, oleanolic and ursolic acids with purities of at least 99.4 %, 99.1 %, and 99.4 %. Molecularly imprinted polymers (MIPs) are synthesized to possess binding sites highly selective to specific molecules, making them very promising adsorbents. Several MIPs were synthetized by precipitation polymerization using different formulations. After preparation, these polymers were characterized by scanning electron microscopy and the most successful ones, in terms of morphological features, were directly tested carrying out batch adsorption experiments. The results disclosed that “MIP1b” material exhibits infinite selectivity for oleanolic acid, the template molecule used in its synthesis. Together with its adsorption capacity – even higher than that of the previously studied C18 phase – these results demonstrate the high potential of “MIP1b” polymer for application on the separation of triterpenic acids. Additional research is required in this topic, where distinct separation approaches may be anticipated. This PhD work culminated in the design and assembling of a laboratory simulated moving bed unit based on a recently patented system using a one- ST valve per column valve scheme, thus allowing the SMB to run under several operation strategies and configurations.

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A cana-de-açúcar (Sacharam spp.) é uma planta de grande importância econômica para o Brasil, usada principalmente na produção de açúcar e etanol, mas que está sujeita ao ataque de diversas doenças, tais como aquelas associadas à proliferação de vírus, bactérias e fungos, que comprometem a produtividade, impactando a produção de biomassa. Estudos que visam estabelecer uma correlação entre a composição micromolecular e a resistência hospedeiro/patógeno ainda são pouco explorados, mas podem auxiliar na investigação dessas interações. Portanto, o objetivo deste estudo foi analisar e comparar os perfis metabólicos da cera epicuticular e de outros metabólitos lipofílicos de folhas de diversas variedades de cana-de-açúcar, por cromatografia a gás acoplada à espectrometria de massas (GCMS). As análises qualitativas resultaram na identificação de 58 compostos na cera epicuticular (138 observados), 41 no extrato hexânico (65 observados) de folhas de cana-de-açúcar. Essas análises foram realizadas por GC-MS após sililação das amostras e alicerçadas principalmente na comparação de índices de retenção e espectros de massas experimentais com dados da literatura e de biblioteca de espectros. Algumas propostas foram também reforçadas pela análise do padrão de fragmentação, entre as quais incluem-se séries homólogas de hidrocarbonetos, ácidos e álcoois graxos e alquilresorcinóis, além de esteroides e triterpenos. A identificação de alquilresorcinóis e do triterpeno simiarenol foi confirmada por análise de frações de cera epicuticular por RMN de 1H e 13C. A julgar pelas massas de cada fração obtida no fracionamento da cera epicuticular de folhas, por cromatografia em camada delgada preparativa, e respectivos espectro de RMN de 1H, conclui-se que os constituintes principais da cera são 5-nonadecil resorcinol, heneicosil resorcinol e o triterpeno...
Sugarcane (Sacharam spp.) is a plant of great importance to Brazil, used mainly in the production of sugar and ethanol, but is subject to several diseases, such as those associated with the proliferation of viruses, bacteria and fungi, that compromise productivity and impacting the production of biomass. Studies aimed to establish the correlation between the micromolecula composition and the host / pathogen resistance are underexplored, but may assist in the understanding of these interactions. Therefore, the aim of this study was to analyze and compare the metabolic profiles of epicuticular wax and other lipophilic metabolites from leaves of different varieties of sugarcane by gas chromatography coupled to mass spectrometry (GC-MS). The qualitative analysis resulted in the identification of 58 compounds in epicuticular wax (seen 138) and 41 compounds in the hexane extract (seen 65) of leaves of sugarcane. These analyzes were performed by GC-MS after sample silylation, and the compound identification was grounded mainly on comparison of retention indices and mass spectra with experimental literature data and spectra libraries. Some proposals have also been enhanced by the fragmentation pattern analysis. The identified compounds include homologous series of hydrocarbons, fatty acids, policosanols and alkyl resorcinols, triterpenes and steroids. The identification of alkyl resorcinols and the triterpene simiarenol was confirmed by 1H NMR and 13C. Judging by the masses of fractions obtained from analysis of the epicuticular wax by preparative TLC, and its 1 H NMR spectrum, it was concluded that the main constituents of wax are 5-nonadecyl resorcinol, 5-heneicosil resorcinol and simiarenol. The comparison of the chemical profiles of epicuticular waxes and the hexane extract of leaves from different sugarcane cultivars showed random qualitative and quantitative variations between the samples, but without...

Orientador: Alberto José Cavalheiro
Banca: Cíntia Duarte de Freitas Milagre
Banca: André Gonzaga dos Santos
Banca: Marcelo Telascrêa
Banca: Flávio Soares Silva
Resumo: A cana-de-açúcar (Sacharam spp.) é uma planta de grande importância econômica para o Brasil, usada principalmente na produção de açúcar e etanol, mas que está sujeita ao ataque de diversas doenças, tais como aquelas associadas à proliferação de vírus, bactérias e fungos, que comprometem a produtividade, impactando a produção de biomassa. Estudos que visam estabelecer uma correlação entre a composição micromolecular e a resistência hospedeiro/patógeno ainda são pouco explorados, mas podem auxiliar na investigação dessas interações. Portanto, o objetivo deste estudo foi analisar e comparar os perfis metabólicos da cera epicuticular e de outros metabólitos lipofílicos de folhas de diversas variedades de cana-de-açúcar, por cromatografia a gás acoplada à espectrometria de massas (GCMS). As análises qualitativas resultaram na identificação de 58 compostos na cera epicuticular (138 observados), 41 no extrato hexânico (65 observados) de folhas de cana-de-açúcar. Essas análises foram realizadas por GC-MS após sililação das amostras e alicerçadas principalmente na comparação de índices de retenção e espectros de massas experimentais com dados da literatura e de biblioteca de espectros. Algumas propostas foram também reforçadas pela análise do padrão de fragmentação, entre as quais incluem-se séries homólogas de hidrocarbonetos, ácidos e álcoois graxos e alquilresorcinóis, além de esteroides e triterpenos. A identificação de alquilresorcinóis e do triterpeno simiarenol foi confirmada por análise de frações de cera epicuticular por RMN de 1H e 13C. A julgar pelas massas de cada fração obtida no fracionamento da cera epicuticular de folhas, por cromatografia em camada delgada preparativa, e respectivos espectro de RMN de 1H, conclui-se que os constituintes principais da cera são 5-nonadecil resorcinol, heneicosil resorcinol e o triterpeno...
Abstract: Sugarcane (Sacharam spp.) is a plant of great importance to Brazil, used mainly in the production of sugar and ethanol, but is subject to several diseases, such as those associated with the proliferation of viruses, bacteria and fungi, that compromise productivity and impacting the production of biomass. Studies aimed to establish the correlation between the micromolecula composition and the host / pathogen resistance are underexplored, but may assist in the understanding of these interactions. Therefore, the aim of this study was to analyze and compare the metabolic profiles of epicuticular wax and other lipophilic metabolites from leaves of different varieties of sugarcane by gas chromatography coupled to mass spectrometry (GC-MS). The qualitative analysis resulted in the identification of 58 compounds in epicuticular wax (seen 138) and 41 compounds in the hexane extract (seen 65) of leaves of sugarcane. These analyzes were performed by GC-MS after sample silylation, and the compound identification was grounded mainly on comparison of retention indices and mass spectra with experimental literature data and spectra libraries. Some proposals have also been enhanced by the fragmentation pattern analysis. The identified compounds include homologous series of hydrocarbons, fatty acids, policosanols and alkyl resorcinols, triterpenes and steroids. The identification of alkyl resorcinols and the triterpene simiarenol was confirmed by 1H NMR and 13C. Judging by the masses of fractions obtained from analysis of the epicuticular wax by preparative TLC, and its 1 H NMR spectrum, it was concluded that the main constituents of wax are 5-nonadecyl resorcinol, 5-heneicosil resorcinol and simiarenol. The comparison of the chemical profiles of epicuticular waxes and the hexane extract of leaves from different sugarcane cultivars showed random qualitative and quantitative variations between the samples, but without...
Doutor

La cuisson Kraft d’un ensemble d’essences de bois, résineux et feuillus, a été caractérisée dans un objectif de compréhension et de différenciation des comportements, ainsi que de modélisation cinétique. Les différentes essences, cuites pures ou en mélanges, ont été caractérisés en cours de cuisson pour leurs propriétés chimiques (lignine résiduelle, polysaccharides, acides héxénuroniques, rendements, composition moléculaire par Py-GC-MS) ainsi que pour leurs propriétés de diffusion et évolutions morphologiques macroscopiques, complétées par des mesures microtomographiques par rayons X pour l’observation des évolutions internes de la structure du bois. Les résultats obtenus apportent à la connaissance générale et à la compréhension de la cuisson Kraft, et contribuent à l’élaboration d’un simulateur mathématique de cuisson
The behaviour during Kraft cooking of a vast series of wood species, including hardwoods and softwoods, have neen studied in a purpose of species comparison and kinetic modelling. The different species were cooked as pure species or mixtures. They were characterized in terms of chemical characteristics (lignin, polysaccharides, hexenuronic acids, pulp yield, molecular composition analysed by Py-GC-MS), and in terms of alkali diffusion properties and morphological evolution during cooking. Macroscopic measurements were completed by microtomographic images on wood chips by X-ray analysis. The results obtained contribute to a general knowledge of Kraft cooking, and also to the development of a mathematical simulator for Kraft cooking modelling

A resposta do LH e do FSH ao estímulo com GnRH, realizado em estádio pré-puberal em pacientes com hipopituitarismo acompanhados até a idade puberal, são úteis para predizer o diagnóstico da deficiência de gonadotrofinas, principalmente nas meninas. O estudo da região codificadora do gene LH em pacientes com hipogonadismo hipogonadotrófico e concentrações normais de LH revelou 5 variantes alélicas. A freqüência das variantes alélicas Arg8 e Thr15 foi similar entre hipogonádicos e adultos normais e a sua presença não interferiu nas concentrações séricas do LH. O estudo das isoformas do LH mostrou um predomínio das isoformas ácidas do LH em hipogonádicos e indivíduos normais, não permitindo atribuir à sua presença a baixa atividade biológica do LH imunorreativo encontrado em 13% dos hipogonádicos
LH and FSH responses to GnRH stimulation carried out in the pre-pubertal stage in patients with hypopituitarism followed until the pubertal stage are useful tools for predicting the gonadotropin deficiency diagnosis, especially in girls. The study of the codifying region of the LH gene in patients with hypogonadotropic hypogonadism and normal LH levels disclosed 5 allelic variants. The frequencies of the allelic variants Arg8 and Thr15 were similar between hypogonadic and normal adults, and their presence did not alter serum LH levels. The study of LH isoforms showed a predominance of acid LH isoforms in hypogonadic and normal subjects, which does not allow us to ascribe to their presence the low biological activity of the immunoreactive LH, found in 13% of the hypogonadic individuals

Introduction : La présence des moisissures et de leurs mycotoxines dans les matrices complexes de papiers est peu étudiée. Notre travail a porté sur la recherche de mycotoxines sur les papiers patrimoniaux altérés par le foxing et les papiers peints moisis issus de logements dont les habitants ont été diagnostiqués comme porteurs de symptômes allergiques et du syndrome des bâtiments malsains. Objectifs : Identifier les espèces fongiques de ces deux types de supports papiers et y déterminer la production de métabolites fongiques. Matériels et Méthodes : Le foxing a été caractérisé par des techniques pluridisciplinaires (physiques, biologiques, bioanalytiques, tests de cytotoxicité). Les métabolites fongiques dans les extraits hydro-organiques de ces papiers ont été recherchés et identifiés par spectrométrie de masse afin d'évaluer s'ils pouvaient être reliés aux espèces fongiques détectées par microbiologie. Puis le risque toxique de ces extraits de papiers a été évalué sur un modèle cellulaire in vitro. Résultats : Pour le foxing, nous avons pu en exclure une origine métallique et montrer que les micro-organismes présents dans celui-ci sont essentiellement des espèces fongiques. Pour les papiers peints, des pics relatifs à des métabolites fongiques ont été retrouvés. Grâce à l'ensemencement individuel d'espèces fongiques sur papier peint et à l'aide de la MS2, nous avons pu relier les composés de m/z 401 et 487 à S. chartarum. Les tests de cytoxicité ont montré une augmentation significative de la cytotoxicité des cellules A549 avec certains papiers peints moisis par rapport au papier peint témoin. Les cellules A549 ont montré une surexpression du TNF-α, de l'IL-8 et du CYP 1A1, après contact avec ces mêmes papiers peints. Discussion-Conclusion : Nous n'avons détecté aucune mycotoxine dans le foxing excluant ainsi d'éventuels liens entre inhalation de mycotoxines émanant de vieux manuscrits et symptomatologie respiratoire. Pour les habitants des logements et leurs symptômes respiratoires, il est difficile de les relier à une espèce fongique donnée ou à un métabolite donné, bien que S. chartarum ait pu être mis en cause. Ces premiers résultats doivent être confirmés par des études ultérieures

碩士
國立中興大學
生物產業機電工程學系所
107
Histamine is one kind of biogenic amines usually found in rotten fish and meat. High concentration of histamine may cause food poisoning, such as scromboid fish poisoning due to high storage temperature. Histamine is odorless, colorless and extremely stable in fish. A method of chemical oxidation of copper was developed to fast fabricate PCB-based copper phosphate electrodes for histamine detection. The copper phosphate electrode was then integrated into a paper-based chromatography chip. The results revealed that the surfaces of the copper phosphate-complex electrodes with flake-shaped nanostructures can be produced within 20 min. Moreover, the copper phosphate complex electrodes presented good electro-catalytic activity toward histamine and histidine. This study successfully developed a paper platform for separation of biogenic amines, in which the chromatography process does not require electric field for the separation. The current increased with histamine concentration and showed good linearity (R2=0.999) in the range of 3.5–111.2 ppm. The calculated LOD of histamine was 0.79 ppm and the resolution of histamine and histidine peak was 11.9. Additionally, the paper-based chromatography chip integrated with copper phosphate electrodes offers several attractive features such as low cost, portability, disposable and, most importantly, a great capacity to promote separation of food safety relevant compounds.

The environmental significance of resin acids originating from pulp and paper industry effluent has led to a detailed investigation of techniques used for their analysis. The chromatographic separation of a number of resin acids (based on those found in Pinus radiata) and their coumarin derivatives was investigated using High Perform- ance Liquid Chromatography (HPLC) with a view to developing a sen- sitive quantitative technique for analysis of total resin acids in pulp and paper industry effluent and in waterways receiving those effluents. Seven resin acids (sandaracopimaric, isopimaric. levopimaric, palust- ric, dehydroabietic, abietic. and neoabietic acid) were reacted with 4-bromomethyl-7-methoxycoumarin (4BrMMC) or 4-bromomethyl-7-acetoxy- coumarin (4BrMAC) to form (7-methoxy-coumarin-4-yl)methyl (MMC) esters and (7-acetoxy-coumarin-4-yl)methyl (MAC) esters respectively. The molar absorptivity of the resin acid MMC esters at 318 nm was shown to be the same for each resin acid ester, thus making it poss- ible to measure them quantitatively by HPLC even though they were not all chromatographically separated. Fluorescence quantum yield meas- urements of the MMC esters however showed a variation in fluorescence response that depended on the resin acid. There was also a variation in fluorescence quantum yield with solvent and water content of the solvent. These two factors precluded the use of the fluorescent properties of the MMC esters for quantitative analysis. Like the MMC esters, the molar absorptivity of the resin acid MAC esters was the same for each resin acid ester, thus enabling use of the chromophore at 310 nm for quantitative analysis. The resin acid MAC esters possessed no fluorescence. but reaction with alkaline methanolic solution was shown to hydrolyse the acetoxy group of the coumarin compound while maintaining the ester linkage to the resin acid. Fu1the1more the fluorescence response of each of the seven resin acids was the same in alkaline media. In the course of these studies, both 4BrMMC and 4BrMAC were found to decompose rapidly when exposed to light with up to half the reagent decomposing in only 30 minutes. The consequences of this photolabil- ity were explored to ascertain the probability of reactions with resin acids during the derivatisation reaction. Similar decomposit- ion products were observed for both coumarin compounds. In the presence of oxygen. 4-methyl-. 4-formyl-. 3-bromo-4-methyl-, and 3-bromo-4-formyl- derivatives of both methoxy and acetoxy coumarin were formed. In the absence of oxygen. and using a high intensity mercury discharge lamp light source. 4BrMMC was shown to produce 4-methyl-, and 3-bromo-4-methyl-7-methoxycoumarin as well as a photo- dimer. The latter two compounds eluted after the 4BrMMC peak thus posing a potential inte1ference problem for HPLC analysis. It was concluded that for the purposes of the analytical technique, it was important to protect solutions containing the coumarin derivatisation reagent from light during all stages of the derivatisation process apart from volumetric transfer of solutions. Derivatisation procedures rep01ted in the literature for similar types of reactions rely on the use of heat and crown ether catalysts to achieve rapid quantitative derivatisation. The effect of tempera- ture, crown ether catalyst, solvent and ratio of derivatisation reagent to resin acid were studied. Quantitative conversion to both the methoxy- and acetoxy-coumarin esters was obtained at room temp- erature, without catalyst. in either acetonitrile or acetone in I 0-15 mins., provided a 10-20 molar excess of derivatisation reagent was present. Application of the technique to extracts from water samples contain mg a variety of other organic compounds and resin acid concentrate- ions was pursued. Apart from the coumarin derivative of dehydroa- bietic acid. all of the resin acid coumarin esters studied co-eluted on a C-8 reverse phase HPLC column. A gradient elution programme based on acetonitrile and water was optimised to obtain adequate resolution of the resin acid coumarin esters from other components present m the effluent extracts. The method was applied to the analysis of resin acids in a river estuary into which pulp and paper effluent was discharged. Based on extraction of 100 ml samples. a detection limit of 0.005 mg C1 was calculated for the technique using 4BrMMC as the derivatisation reagent and UV absorption for detection. A detection limit of 0. OOO 1 mg C 1 was calculated for the techniques using 4BrMAC with fluorescence detection of the hydrolysed ester derivative. The lower detection limit associated with 4BrMAC esters offers a significant improvement over current gas chromato- graphy methods using flame ionisation detection.

碩士
國立中山大學
機械與機電工程學系研究所
106
This paper presents a novel paper-based microfluidic cassette integrated two-dimensional paper chromatography and paper spray mass spectrometry (PS-MS) detection in bioanalysis and food-safety applications. The cassette can be fabricated in a single-process through a dual-extrusion 3D printer equipped with ABS and ABS conductive polymers such that delicate fabrication processes can be excluded for producing the cassette. The sample injection, separation, concentration and electrospray ionization could be completed in the single microfluidic cassette through the specially designed cassette, paper-based microfluidic and the embedded polymer electrode. The liquid sample is directly applied to the sample trench and then separated and concentrated using a 2D paper chromatography technique. To further improve the performance of the paper-based microfluidic system, several special designs including a tip contact for uniform developing solution dispersion, several sacrificial wings for sample smear elimination and sculpted holes for electrical isolation during paper spray ionization. Results shows that the sacrificial wing and throttle valve can increase the number of theoretical plate to about 3.9 and 1.6 times respectively in the first-dimensional chromatography, and greatly reduce the sample residue on the paper tip. The second-dimensional chromatography has increased the signal strength by nearly a hundred times. The developed system can detect the residual pesticides in fresh grape, and the residual drug in body fluid.

碩士
中原大學
化學研究所
94
A specific designed device featured with on-line direct sampling, dilution, and injection has been utilized to couple a vertically hanging immobilized cellulase bioreactor with the high-performance liquid chromatography (HPLC) system to make a successful analysis of the three major carbohydrate products, glucose, xylose, and cellobiose in the cellulase hydrolysate in this research. This analysis system could successively monitor the enzymatic hydrolysis of paper cellulose over a period of 96 hours and the monitoring stability was very good. Four different quantification methods for analysis of the three major carbohydrate products were compared and the internal standard calibration method with on-line dilution procedure was proved to be the best quantitative method in terms of the accuracy, precision, limit of detection, and reduction of systematic error. With this method, the analysis for glucose had an accuracy of 99.9%, the relative standard deviation (RSD) below 2.4%, and the limit of detection of 2.1 ppm. In addition, matrix matching between the reaction sample and standard solution was found extremely important in the preparation of standard calibration curves with the use of refractive index detection. We also found that the trace carbohydrate products including galactose, arabinose, and mannose were produced during the enzymatic hydrolysis of paper cellulose. When the hydrolysis was ended, the salt and matrix in the enzymic hydrolysate was eliminated by the solid-phase extraction (SPE). Then, these trace carbohydrates were analyzed by liquid chromatography-mass spectrometry (LC-MS) coupled with an ion exclusion chromatographic column. The interface and ionization method of LC-MS was the eletrospray ionization (ESI). The concentration of the three trace carbohydrates was successfully determined by the LC-MS method, and the trace carbohydrate products galactose, arabinose, and mannose were demonstrated that they were existed in the hydrolysate indeed.

(AJ) Food contact materials pose a risk to human health due to a variety of contaminants which they can release into food. These compounds, migrants, include aromatic hydrocarbons, dialkyl phthalates, bisphenols, printing ink photoinitiators, and perfluoroalkyl compounds. The determination of all these substances can be expensive and time-consuming since universally applicable analytical approaches are not available nowadays. This work attempted to develop methods for the simultaneous determination of migrants from all of the mentioned groups in paper-based food contact materials and fatty food. A total of 68 contaminants were studied in paper products using liquid chromatography and gas chromatography coupled with tandem mass spectrometry detection. All analytes were isolated simultaneously using the modified "QuEChERS" method. This method demonstrated acceptable recovery and repeatability for most analytes in the validation study; LOQs ranged from 1.3 to 220 µg/kg. Analysis of 132 real paper products confirmed the occurrence of almost all studied analytes, which were often present in complex mixtures and at concentrations up to 628 mg/kg. A total of 41 potential contaminants were monitored in fatty foods by liquid chromatography with tandem mass detection. Contamination of the mobile phase by...

碩士
國立臺灣科技大學
材料科學與工程系
107
The nanohybrids of surface-enhanced Raman scattering (SERS) detection papers were successfully fabricated by gold nanoparticles (AuNPs) immobilized on the graphene oxide (GO) nanosheets-cellulose nanofibers (TOCNs) substrates. TOCNs were extracted from the recycling cellulose fibers from the food wastes, and then modified by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) to exfoliate it. GO and TOCNs were further blended together to fabricate papers by the paper machine. Furthermore, AuNPs were (ca. 10 nm) in-situ grown on the GO@TOCNs paper as SERS substrate for biomolecules and water pollutants detection. [2] The result show that the tensile strength of AuNPs@GO@TOCNs composites is 7-8 times higher than the pristine TOCNs papers, showing the great mechanical properties after the addition of GO and AuNPs. X-ray diffraction patterns show that TOCNs still maintain great crystallinity, even though diameters of cellulose fibers decrease from micro- to nano-scale. The biomolecules of rhodamine 6G and direct blue can be detected by Raman spectroscopy and chromatographic separation. The limit of detection (LOD) on AuNPs@GO@TOCNs SERS paper is lower than 10-7 M. The reason is that GO can doubly enhance the SERS intensity by the surface plasmon resonance in the symmetrical benzene structure. Finally, the nanohybrids paper can be used as a chromatographic paper to separate the samples by modulated the ratios of GO and TOCNs. Thus, AuNPs@GO@TOCNs papers are potential to apply in the platform of the chromatographic separation and rapid SERS detection of biomolecules.