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Salazar, Vania Cristina Rodríguez. "Desenvolvimento de métodos analíticos por cromatografia gasosa acoplada à espectrometria de massas para a identificação e quantificação de anatoxina-A em amostras de água e florações algais." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-07022007-163018/.
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A poluição dos corpos d\'água é de grande preocupação mundial, pois a maioria da população utiliza a água doce de reservatórios, represas ou rios como principal fonte de água potável. A presença no Brasil de florações de cianobactérias capazes de produzir anatoxina-a, revela a necessidade de métodos simples e rápidos que permitam sua detecção e monitoramento. Neste trabalho foram desenvolvidos, otimizados e validados dois métodos analíticos por GC/MS para identificação e quantificação de anatoxina-a em amostras de água e florações, respectivamente. A norcocaína foi usada como padrão interno em ambos os métodos. Os íons escolhidos para serem monitorados foram (íons quantificadores sublinhados): anatoxina-a: 191,164, 293 e norcocaína: 195, 136, 168. As curvas de calibração dos métodos mostraram-se lineares nas faixas de 2.5-200 ng.mL-1 e 13-250 ng.mg-1. Os limites de detecção obtidos foram 2 ng.mL-1 e 10 ng.mg-1. Os métodos demonstraram sensibilidade e especificidade adequada para seu uso no monitoramento ambiental da anatoxina-a.The water pollution is a big concern around the world, since the most of cities use freshwater reservoirs, dams or rivers as the main drinking water suppliers. Cyanobacterial blooms capable to produce anatoxin-a are regularly present in Brazilian waters. Therefore, there is a necessity of simple and rapid analytical methods to monitor this cyanotoxin. In the present work, two analytical methods by GC/MS for identification and quantification of anatoxin-a in water and algae bloom samples were developed, optimized and validated. Norcocaine was used as internal standard in both methods. The ions chosen to be monitorated were (quantification ions underlined): anatoxin-a 191, 164, 293 and norcocaine: 195, 136, 168. Both method calibration curves showed linearity in the ranges of: 2.5-200 ng.mL-1 and 13-250 ng.mg-1. The obtained limit of detection were: 2 ng.mL-1 and 10 ng.mg-1. The methods showed sensitivity and specificity enough to be used routinely as a tool for anatoxin-a monitoring.
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Martendal, Edmar. "Novas estratégias de otimização para a técnica de SPME e SPME com recobrimento internamente refrigerado." reponame:Repositório Institucional da UFSC, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/95859.
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Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2011Made available in DSpace on 2012-10-26T06:35:45Z (GMT). No. of bitstreams: 1 290251.pdf: 1265428 bytes, checksum: a111e0c6a721f9c9c6d846c18ec17b62 (MD5)
Esta Tese apresenta três novas estratégias de otimização, sendo duas aplicadas à técnica de microextração em fase sólida (SPME) com recobrimento internamente refrigerado (cold-fiber SPME-CF-SPME) e uma aplicada à técnica de SPME comercialmente disponível. Todas as etapas de otimização foram realizadas multivariadamente através de planejamento composto central. A primeira parte do trabalho consistiu em uma nova estratégia de otimização para amostragem em fase gasosa utilizando CF-SPME. Duas classes de compostos, ésteres de ftalato (EF) e hidrocarbonetos policíclicos aromáticos (HPA), com volatilidades distintas foram escolhidos para esse estudo, no qual se propôs um novo método baseado no uso de duas temperaturas da fibra no mesmo procedimento de extração, objetivando maximizar a quantidade extraída de todos os compostos no menor tempo possível. Comparações foram realizadas entre a nova proposta e o procedimento convencional, sendo obtidos excelentes resultados. A segunda parte do trabalho consistiu na utilização pela primeira vez da técnica de CF-SPME em uma combinação dos modos de extração direto e a partir do headspace para extração simultânea de EF e HPA de uma suspensão de solo em água. Força iônica, tempo de extração, pH e temperatura da fibra foram avaliados para cada modo de extração separadamente e posteriormente para a combinação deles. Comparações foram realizadas entre a utilização de cada um dos modos separadamente, a combinação deles e a utilização do procedimento convencional da CF. O procedimento proposto mostrou melhores resultados em todos os casos. O último estudo realizado consistiu na utilização da técnica de SPME comercial para extração da fração volátil de matrizes vegetais. Tempo e temperatura de extração foram avaliados com a fibra DVB/CAR/PDMS. Propôs-se um novo método baseado no uso de duas temperaturas de extração objetivando maximizar a quantidade extraída de compostos com volatilidades/polaridades distintas. Os dois métodos foram comparados pela análise de cinco amostras, sendo o último mais eficiente em todos os casos.
This study presents three new optimization approaches, two of which were applied to internally-cooled solid-phase microextraction technique (or cold-fiber SPME - CF-SPME) and one to a commercially available SPME. All optimization steps were carried out by means of central composite designs. The first part of the study consisted of a new optimization strategy for gaseous phase sampling using CF-SPME. Phthalate esters (PEs) and polycyclic aromatic hydrocarbons (PAHs) were the model compounds employed in this study. A new method based on the use of two coating temperatures in the same extraction procedure was proposed aiming at maximizing the amount extracted in a minimum extraction time. Comparisons between the proposed and conventional methods were carried out and excellent results were obtained. The second part of the study consisted of the utilization of CFSPME in a combination of extraction modes, direct and headspace, for the simultaneous extraction of PEs and PAHs from a suspension of soil in water. Ionic strength, extraction time, sample pH and fiber temperature were evaluated for each extraction mode separately and then for a combination of the two. Comparisons were made between the use of each mode separately, a combination of the two and the conventional procedure of CF-SPME. The proposed procedure was better in all cases. Finally, a commercially available SPME fiber was used to extract the volatile fraction of plant matrices. Extraction time and temperature were evaluated using DVB/CAR/PDMS fiber. In view of the different optimum extraction temperatures obtained for each group of compounds, a new method based on two extraction temperatures in the same procedure was proposed. The conventional method based on a single extraction temperature was compared to the proposed method by analyzing five samples. The proposed method was shown to be more efficient in all cases.
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Sebben, Viviane Cristina. "Análise de efedrinas e anfetamina em urina empregando spe e spme por cg/em/em." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/12004.
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O Brasil ocupa posição de destaque no consumo mundial de anfetaminas, contrariamente à tendência mundial de retração. Devido aos efeitos colaterais e ao alto potencial de abuso, a produção e comercialização de anfetaminas vêm sendo controladas no mundo inteiro. Com a restrição de uso, houve um retorno a procura pelos equivalentes naturais, especialmente as efedrinas presentes em diversas especialidades farmacêuticas, utilizadas no tratamento de doenças respiratórias. São componentes de vários compostos emagrecedores, suplementos alimentares e dietéticos utilizados para perda de peso e ganho de massa muscular. Face ao uso indiscriminado e a grande incidência de resultados falso-positivos nos testes de triagem para anfetaminas por imunoensaio enzimático homogêneo, fazem-se necessários testes confirmatórios. Neste sentido, este trabalho se propôs a desenvolver um método confirmatório simples e rápido para detecção, identificação e quantificação de efedrinas (efedrina/pseudoefedrina) em amostras de urina por por cromatografia a gás / espectrometria de massas-massas (CG/EM/EM), passível de ser adotado na rotina de laboratórios de análises toxicológicas. Devido à complexidade da matriz e as peculiaridades do analito, inicialmente procedeu-se o estudo do tratamento da amostra, considerando as etapas de derivatização, extração, pré-concentração e purificação, de modo a fornecer um extrato límpido, livre de impurezas, interferentes e com melhor sensibilidade, linearidade e seletividade analítica. Os métodos de extração usados foram extração líquido-líquido (ELL), extração em fase sólida (SPE) e microextração em fase sólida (SPME). Os resultados indicaram que o reagente de derivatização ciclohexanona foi o que apresentou melhor desempenho, menor custo e promoveu maior seletividade dos diasterômeros EF/PEF em colunas normais de CG. Sendo que o método mais apropriado para a detecção e identificação de efedrinas/anfetamina por CG/EM é a SPME levando em consideração características como simplicidade, rapidez, custo, recuperação e ausência de interferentes. Entretanto, considera-se valido o uso de SPE para a quantificação, devido à possibilidade de pré-concentração do analito.Brazil is one of the biggest amphetamine consumers in the world, going against the worldwide retraction tendency. Due to serious adverse effects and high abuse potential, the production and commercialization of amphetamines has been controlled around the world. With the restriction of its use, there was a return in the search of natural equivalents, especially the ephedrines found in many medicines utilized in the treatment of respiratory diseases. Furthermore, they are components of dietary supplements used to lose weight and muscular mass gain. Because of the indiscriminate use and the high incidence of false-positive results in the amphetamines screening tests by enzyme immunoassay technique, it is necessary confirmatory tests. In this way, the aim of this work is to develop a confirmatory simple and quickly method for the detection and quantification of ephedrines (ephedrine and pseudoephedrine) gas chromatography / mass-mass spectrometry (GC/MS/MS), with possibility to be adopted in toxicological analyses laboratorial routine. Due to the complexity of the matrix and analyte peculiarities, initially proceeds the study of sample treatment, considering the derivatization, extraction, pre-concentration and purification steps, obtaining a limpidous extract, free of impurities, interferents and with better sensitivity, linearity and analytical selectivity. The extraction method used were liquid-liquid extraction (LLE), solid-phase extraction (SPE) and solid-phase microextraction (SPME). The results indicate that cyclohexanone was the derivatization agent with the best performance, lower price and good selectivity in diasteromers EF/PEF separation in normal GC columns. The most appropriate method for detection and identification of ephedrines/amphetamine by GC/MS is SPME, considering characteristics as simplicity, speed, cost, recovery and absence of interferents. However, the use of SPE must be considered to quantification, since it allowed analyte pre-concentration.
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Silva, Rogerio Cesar da. "Dispositivos hifenados para microextração em fase solida." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250197.
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Orientador: Fabio AugustoTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Doutorado
Quimica Analitica
Doutor em Quimica
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Jou, Kuen-Da. "Integrated analysis and pattern recognition of Swiss cheese aroma by SPME/GC, SPME/GC/MS and electronic noses /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487946776020555.
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Stien, Jan. "Festphasenmikroextraktion (SPME) eine Alternative zu klassischen Extraktionstechniken /." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=961251204.
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Biajoli, Andre Francisco Pivato 1978. "Fibras para SPME (microextração em fase solida) recobertas com novos ormosils sol-gel." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250195.
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Orientador: Fabio AugustoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Este trabalho descreve a obtenção de fibras para microextração em fase sólida a partir do processo sol-gel utilizando-se 3-aminopropiltrimetoxissilano (APTMS) como precursor/modificador orgânico e polidimetilsiloxano hidroxiterminado (PDMS-OH) como modificador orgânico. O material preparado foi caracterizado física e quimicamente através de espectroscopia de absorção no infravermelho e análise termogravimétrica. As fibras recobertas com este material foram avaliadas morfologicamente através de microscopia eletrônica de varredura e caracterizadas analiticamente através do estudo de seus perfis de extração e de dessorção, além de terem sido comparadas com fibras comerciais. Como resultados, verificou-se que os recobrimentos produzidos podem ser utilizados em temperaturas de até 300 °C e que estes apresentam uma morfologia irregular, aspecto favorável para dispositivos de SPME. O perfil de extração mostrou que a fibra possui tempos de equilíbrio rápidos para hidrocarbonetos aromáticos (da ordem de 5 min); o perfil de dessorção mostrou que, após 5 s de injeção, os mesmos analitos são completamente removidos do recobrimento. Comparada com fibras comerciais de poliacrilato (PA - polar) e PDMS (apolar), a fibra sol-gel apresentou melhores propriedades sortivas tanto no tocante a compostos polares (ácidos carboxílicos e álcoois) quanto a compostos de media polaridade (ésteres). A fibra sol-gel foi aplicada com sucesso em determinações quantitativas de clorofenóis em madeiras e águas
Abstract: This work describes the preparation of Solid Phase Microextraction Fibers through the sol-gel process using 3-aminopropyltrimethoxysilane as precursor/organic modifier and polydimethylsiloxane (PDMS) as organic modifier. The chemical and physical properties of the material obtained were studied through infrared absorption spectroscopy and thermogravimetric analysis. The morphology of the fibers obtained were evaluated by scanning electron microscopy; their analytical properties were studied through extraction and desorption profiles and also through comparison with commercial SPME fibers. As results, it was observed that the coatings prepared presented an irregular, rugged surface, desirable characteristics for SPME devices, and may be used up to 300 °C with no thermal decomposition. The extraction profile showed that the fiber allows fast equilibration times (in the order of 5 min) and fast desorption kinetics, with 5 s being needed for complete removal of extracted compounds from the fiber coating. Compared to commercial polyacrylate (PA, polar) and PDMS (apolar) fibers, the sol-gel fiber presented enhanced sorptive properties for polar compounds (carboxylic acids and alcohols) as well as for intermediate polarity ones (esters). The sol-gel fiber was successfully applied to quantitative determination of chlorophenols in wood and water
Mestrado
Quimica Analitica
Mestre em Química
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Silva, Bruno José Gonçalves da. "Avaliação técnica SPME/LC na análise de antidepressivos em amostra de plasma para fins de monitorização terapêutica." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-17082007-114009/.
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As recentes técnicas miniaturizadas de preparo de amostra, microextração em fase sólida (SPME) e in tube SPME, apresentam uma série de vantagens em relação aos métodos clássicos de extração (extração líquido-líquido e extração em fase sólida), tais como: não requer instrumentação analítica sofisticada, utilização de pequenas quantidades de solventes orgânicos, rápido processo operacional, permite automação das análises, a reutilização das fases extratoras, e integra em um único sistema a extração, concentração e introdução da amostra no cromatográfico. Esta dissertação tem como objetivo a padronização, validação e comparação dos métodos SPME/LC-UV com dessorção off line e in tube SPME/LC-UV, para a análise dos antidepressivos da nova geração (mirtazapina, citalopram, paroxetina, duloxetina, fluoxetina e sertralina) em amostras de plasma para fins de monitorização terapêutica. As variáveis: fase extratora, pH da matriz, tempo e temperatura de extração e de dessorção e força iônica apresentaram grande influência na eficiência do processo SPME. O método SPME/LC-UV padronizado, apresentou limite de quantificação (LQ) de 25 a 50 ng mL-1, ampla faixa de linearidade (LQ ? 500 ng mL-1, r2 > 0,9970) e precisão inter ensaios com coeficientes de variação menor que 15% para todos os analitos. Apesar das baixas taxas de recuperação obtidas, de 8,1% (citalopram) a 17,1% (mirtazapina), o método SPME/LC-UV apresentou seletividade e sensibilidade analítica adequada. As variáveis: pH da matriz, fluxo e número de ciclos aspirar/dispensar e volume de amostra apresentaram grande influência na eficiência do processo in tube SPME. A etapa de precipitação de proteínas do plasma, anterior ao processo de extração, foi necessária para a eliminação dos compostos endógenos. O método in tube SPME/LC-UV padronizado apresentou seletividade adequada, precisão inter ensaios com coeficiente de variação menor que 10%, LQ de 20 a 50 ng mL-1, linearidade na faixa de concentração do LQ a 500 ng mL-1, com r2 > 0,9983 para todos os analitos e recuperação absoluta de 5,32% (mirtazapina) a 43,5% (sertralina). A técnica in tube SPME, quando comparada à SPME, permitiu a automação das análises, menor exposição do analista às amostras biológicas e solventes orgânicos, menor tempo de análise e menor volume de amostra de plasma. A eficácia dos métodos, SPME/LC-UV e in tube SPME/LC-UV, foi comprovada através das análises de amostras de plasma de pacientes em terapia com os antidepressivos, para fins de monitorização terapêutica.The recent miniaturized sample techniques preparation, solid phase microextraction (SPME) and in tube SPME, present several advantages when compared with classic extraction methods (liquid-liquid extraction and solid phase extraction), such as: it does not require sophisticated analytical instrumentation, use small organic solvent amounts, fast operational process, automation of the analyses, reuse extraction phases, and incorporates, into a single procedure, sample extraction, concentration and sample introduction. The aim of this work is development, validation and comparison of methods SPME/LC-UV with off line desorption and in tube SPME/LC-UV, for analyses of antidepressants of the new generation (mirtazapine, citalopram, paroxetine, duloxetine, fluoxetine and sertraline) in plasma samples for therapeutic drug monitoring. Variables: extraction phase, matrix pH, time and temperature of extraction and desorption and ionic strength showed great influence in SPME process efficiency. The method SPME/LC-UV presented limit of quantification (LOQ) variety from 25 to 50 ng mL-1, wide range the of linearity (LOQ 500 ng mL-1, r2 > 0.9970) and interassays precision with coefficient of variation lower than 15% for all analytes. Although the low recovery, from 8.1% (citalopram) to 17.1% (mirtazapine), the method SPME/LC-UV presented adequate selectivity and analytical sensitivity. Variables: matrix pH, flow and number of aspirate/dispense cycles and sample volume showed great influence in the in tube SPME process efficiency. The protein precipitation of the plasma steps, previous to the extraction process, was necessary for the endogenous compounds elimination. The method in tube SPME/LC showed adequate selectivity, interassays precision with coefficient of variation lower than 10%, LOQ variety from 20 to 50 ng mL-1, linearity in range concentration from LOQ to 500 ng mL-1, with r2 > 0.9983 for all analytes and recovery from 5.32% (mirtazapine) to 43.5% (sertraline). The technique in tube SPME, compared with the SPME, permitted the automation of the analyses, minor exposition of the analyst to the biological samples and organic solvent, shorter analyses time and minor plasma sample volume. The effectiveness methods, SPME/LC-UV and in tube SPME/LC-UV, was proven through the analyses of plasma samples of patients in therapy with antidepressants, for therapeutic drug monitoring.
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Olivares, Igor Renato Bertoni. "\"Desenvolvimento, otimização e validação da técnica HS-SPME-GC/MS para análise de amostras obtidas do Rio Atibaia através da aplicação de uma sistemática \"ISO\" para diagnóstico ambiental de áreas contaminadas\"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-16042007-171617/.
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Neste trabalho foi desenvolvida, otimizada, e validada, uma metodologia para análise de 15 pesticidas organoclorados em sedimento através de HS/SPME-GC/MS. Esta metodologia foi aplicada para análise de amostras reais visando à realização de um diagnóstico da contaminação por pesticidas organoclorados do Rio Atibaia, principalmente em sua região próxima a contaminação oriunda da empresa Shell Brasil S.A. unidade de Paulínia. Para realização deste diagnóstico, também foi desenvolvida uma metodologia padronizada para diagnóstico ambiental de áreas contaminadas, embasada principalmente em conceitos de Gestão de Qualidade e Meio Ambiente abordadas nas normas ISO 17025, ISO 14001 e GLP. Finalmente, aplicando a metodologia analítica validada, e a metodologia para realização de um diagnóstico ambiental, foi realizado o diagnóstico da presença de pesticidas organoclorados no Rio Atibaia, indicando a existência de diferentes pesticidas organoclorados em sedimento, com destaque para os compostos DDE e BHC que se encontraram em valores acima dos recomendados pela legislação canadense. Os resultados encontrados também demonstraram que as metodologias desenvolvidas foram adequadas para análise de uma contaminação real.In this work a methodology was developed, optimized and validated for the analysis of 15 organochlorine pesticides in sediment through HS/SPME-GC/MS. This methodology was applied to the analysis of real samples for diagnosis of the organochlorine pesticides contamination of the Atibaia River, mainly in its region close the contamination from company Shell Brasil S.A. site of Paulínia. For accomplishment of this diagnosis, also a standard methodology for environmental diagnosis of contaminated areas was developed, mainly based in concepts of Quality Management and Environmental Management find in standards like ISO 17025, ISO 14001 and GLP. Finally, applying the validated analytical methodology and the methodology proposed for environmental diagnosis, the diagnosis of the organoclhorine pesticide presence in the Atibaia River was performed, indicating different organoclorine pesticides in sediment, mainly DDE and yBHC, which were found in values above of those recommended by the Canadian legislation. The results also demonstrated that the developed methodologies are adequate for analysis of a real contamination.
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Menezes, Filho Adalberto. "Desenvolvimento, validação e aplicação de metodologias para determinação de resíduos de agrotóxicos em manga por SPME-GC-MS e SPME-HPLC-UV-Vis." Instituto de Química, 2010. http://repositorio.ufba.br/ri/handle/ri/20281.
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Foram desenvolvidas, validadas e aplicadas duas metodologias analíticas por SPME e análise por GC-MS e HPLC-UV-Vis, para determinar resíduos de agrotóxicos em manga. 14 compostos foram analisados por GC-MS (clofentezina, carbofuran, diazinon, parationa, malationa, fentiona, tiabendazol, imazalil, bifentrina, permetrina, procloraz, piraclostrobina, difenoconazol, azoxistrobina) e 10 por HPLC-UV-Vis (tiabendazol, carbofuran, azoxistrobina, procloraz, fentiona, clofentezina, permetrina, abamectina, carbosulfan e bifentrina). Diferentes parâmetros que influenciam na eficiência da extração foram avaliados (Tipo de fibra, modo de extração, temperatura e tempo de extração e dessorção, velocidade de agitação e força iônica). Os melhores resultados foram obtidos com fibra de PA e DI a 50°C por 30 min, com agitação a 250 rpm e dessorção por 5 min a 280°C no GC- MS e no modo estático por 15 min na interface SPME-HPLC. Na validação foram avaliados o efeito da matriz, a linearidade das curvas analíticas, LOD, LOQ, precisão e exatidão. O método por SPME-GC-MS apresentou linearidade entre 3,3 e 1665,0 µg kg-1, LOD entre 1,0 e 3,3 µg kg-1 e LOQ entre 3,3 e 33,3 µg kg-1. O método por SPME-HPLC- UV-Vis apresentou linearidade entre 2,0 e 250,0 µg kg-1, LOD entre 0,6 e 3,3 µg kg-1 e LOQ entre 2,0 e 10,0 µg kg-1. Nos dois métodos foram obtidos CV menores que 20%. Os métodos foram aplicados na análise de amostras coletadas em Salvador-BA e Aracaju-SE. Nas amostras de Salvador foram detectados resíduos de sete compostos e nas de Aracaju resíduos de cinco compostos. Entretanto, as concentrações estavam abaixo dos valores estabelecidos pela Legislação Brasileira.
Were developed, validated and applied two analytical methodologies by SPME and GC-MS and HPLC-UV-Vis analysis to determine pesticide residues in mango. 14 compounds were analyzed by GC-MS (clofentezine, carbofuran, diazinon, methyl parathion, malathion, fenthion, thiabendazole, imazalil, bifenthrin, permethrin, prochloraz, pyraclostrobin, difenoconazole, azoxystrobin) and 10 for HPLC-UV-Vis (thiabendazole, carbofuran, azoxystrobin, prochloraz, fenthion, clofentezine, permethrin, abamectin, bifenthrin and carbosulfan). Different parameters influencing the extraction efficiency were evaluated (fiber type, extraction mode, temperature, extraction and desorption times, stirring velocities and ionic strength. The best results were obtained using PA fiber and DI mode at 50°C form 30 min, along with stirring at 250rpm and desorption for 5 min at 280°C in the GC-MS and estatic mode for 15 min in the SPME-HPLC interface. For validation, we assessed the matrix effect, the linearity of calibration curves, LOD, LOQ, precision and accuracy. The method for SPME-GC-MS showed linearity between 3.3 and 1665.0 mg kg- 1, LOD between 1.0 and 3.3 µg kg-1 and LOQ between 3.3 and 33.3 µg kg-1. The method for SPME-HPLC-UV-Vis showed linearity between 2.0 and 250.0 µg kg-1, LOD between 0.6 and 3.3 µg kg-1 and LOQ between 2.0 and 10.0 µg kg-1. In both methods were obtained CV below 20%. The methods were applied in the analysis of samples collected in Salvador- BA and Aracaju-SE. In samples from Salvador seven compounds residues were detected and in samples from Aracaju five compounds residues were detected. However, the concentrations were below the values established by Brazilian legislation
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Stadelmann, Iris Patricia. "Extraction of alcohols from gasoline using solid phase microextraction (SPME)." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/32976.
Full textAbstract:
It is common practice to add oxygenates, such as ethers or alcohols, to gasoline in areas
suffering from ozone or smog problems in order to reduce pollution. The most commonly used
oxygenates are ethanol (EtOH) and methyl tert-butyl ether (MTBE). However, MTBE is now
forbidden by the environmental protection agency (EPA) because of the possibility of ground
water contamination. The current trend is to use EtOH, therefore this work focuses on the
analysis and quantification of EtOH in gasoline by solid phase microextraction (SPME). The
major problem in quantifying EtOH in gasoline is the coelution of hydrocarbons with EtOH.
There have been several approaches to solve this problem; among the chromatographic ones,
three major types have been proposed: (1) the first one uses a detector selective for oxygen containing compounds; (2) the second one uses two or more columns; (3) and the third one uses an extraction step prior to GC analysis. In this work an extraction step with water is used prior to a solid phase microextraction (SPME) sample preparation coupled to a gas chromatographic (GC) analysis.
Solid phase microextraction is a recent technique, invented by Pawliszyn in 1989, and available commercially since 1994. A fiber is used to extract small amounts (ppm, ppb, ppt) of analytes from a solution, usually water. The fiber is beneficial in concentrating analytes. Most work using SPME has been done with hydrophobic (non polar) analytes, extracted using a polydimethylsiloxane (PDMS; non polar) coating on a fused silica fiber. Since very little work has been done with polar analytes, the novel approach of this work is the extraction of EtOH.
Since EtOH is the analyte of interest, a polar fiber, carboxen/polydimethyl siloxane
(Car/PDMS) is used. Two methods are used for quantification of EtOH in gasoline: the method
of a standard calibration curve, and the method of standard addition. They are both
successful in quantifying the amount of EtOH in gasoline. The relative errors, with the
method of standard addition, vary from 5.3% to 14%, while the ones with the method of
calibration curve vary from 1.6% to 7.2%. Moreover, some extraction time studies for both
direct and headspace sampling are performed. Direct sampling shows the presence of an
equilibrium condition for the carboxen/PDMS fiber, for which no extraction theory is
available. Conversely, headspace sampling shows no equilibrium state; after a sampling time
of one hour, the amount of EtOH extracted decreases with sampling time. This is probably due
to displacement of EtOH by other compounds in the fiber.
Master of Science
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Milo, John A. "Quantitation of Halogenated Anisoles in Wine via SPME – GC/MS." Connect to resource online, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1230924488.
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Zorn, Eva-Christina. "Methoden der spurenanalytischen Bestimmung von Estrogenen im Abwasser." Doctoral thesis, [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969411871.
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Batista, Alex Domingues. "Fibras para SPME (Microextração em fase sólida) recobertas com sílica modificadas por grupos vinila." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250194.
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Orientador: Fabio AugustoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: No trabalho estudou-se o preparo de fibras para Microextração em Fase Sólida (SPME) com recobrimentos baseados em sílicas organicamente modificadas através de processo sol-gel. O modificador utilizado foi o viniltriemetoxisilano para a obtenção de um revestimento inicial que posteriormente foi recoberta com poliestireno através da polimerização de monômeros de estireno catalisada por luz ultravioleta. As fibras foram caracterizadas química e morfologicamente através de Microscopia Eletrônica de Varredura, Espectroscopia no Infravermelho e Análise Termogravimétrica. Os recobrimentos apresentaram uma estrutura compacta, sem a presença visível de poros com uma espessura de 97 mm. Eles se apresentaram estáveis termicamente até uma temperatura de aproximadamente 320°C. As fibras foram utilizadas com sucesso na quantificação de BTEX em água de torneira, as curvas analíticas obtidas apresentaram coeficientes de correlação linear acima de 0,99. Os limites de detecção calculados pela curva analítica foram para benzeno, tolueno, etilbenzeno e o-xileno foram respectivamente 0,023, 0,042, 0,027 e 0,061 mg.L. As novas fibras foram utilizadas também na quantificação de androstenona e escatol em toucinho suíno onde também observado um coeficiente de correlação linear para a curva analítica acima de 0,99. Os limites de detecção foram 0,003 mg.g para androstenona e 0,009 mg.g para escatol
Abstract: In this work we studied the preparation of fibers for Solid Phase Microextraction (SPME) with coatings based on organically modified silica via sol-gel process. Vinyltrimethoxysilane was used as modifier for obtaining an initial coat that was later covered with polystyrene by polymerizing styrene monomers catalyzed by ultraviolet light. The fibers were characterized chemically and morphologically by scanning electron microscopy, infrared spectroscopy and thermogravimetric analysis. The coatings had a compact structure without the visible presence of pores with a thickness of 97 micrometers. They showed thermal stability up to a temperature of about 320°C. The fibers were successfully used in the quantification of BTEX in tap water, the analytical curves showed correlation coefficients above 0.99. The detection limits were calculated by the analytical curve of benzene, toluene, ethylbenzene and o-xylene were respectively 0.023, 0.042, 0.027 and 0.061 mg.L. The new fibers were also used for quantification of skatole and androstenone in pig fat which also observed a linear correlation coefficient for the calibration curve above 0.99. The detection limits were 0.003 mg.g for androstenone and 0.009 mg.g for skatole
Mestrado
Quimica Analitica
Mestre em Química
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Bocato, Mariana Zuccherato. "Avaliação de modelos microbiológicos e modelos biomiméticos no metabolismo estereosseletivo da risperidona por cromatografia líquida de alta eficiência." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-08082012-172645/.
Full textAbstract:
A risperidona é um medicamento antipsicótico que quando metabolizada da origem a dois metabólitos hidroxilados quirais, a 7-hidroxirisperidona (7-RispOH) e a 9-hidroxirisperidona (9-RispOH). A 9-RispOH apresenta as mesmas propriedades farmacológicas que a risperidona e já é comercializada como fármaco, com o nome genérico de paliperidona. Estudos em humanos mostram que existem diferenças na disposição cinética dos enantiômeros da 9-RispOH, com uma maior prevalência do enantiômero (+)-9-RispOH em plasma. Dessa forma, este trabalho teve como finalidade avaliar a capacidade de algumas espécies de fungos e também de catalisadores de Jacobsen em (bio)transformar enantiosseletivamente a risperidona em seu metabólito ativo 9-RispOH. Para tanto, foi desenvolvido um método de separação para a risperidona e seus metabólitos utilizando cromatografia líquida de alta eficiência quiral. Este método foi então aplicado nos estudos de biotransformação enantiosseletivo e nos estudos de catálise assimétrica. A separação cromatográfica foi realizada empregando a coluna Chiralcel OJ-H e metanol:etanol (50:50, v/v) + 0,2% de trietilamina como fase móvel. A vazão e temperatura utilizadas foram 0,8 mL min-1 e 25oC, respectivamente. Para extração dos analitos do meio de cultura, foi empregada a microextração em fase sólida (SPME) como técnica de preparação de amostra. O processo de SPME foi realizado utilizando uma fibra C18 mergulhando diretamente a fibra na amostra por 30 minutos e dessorvendo a fibra diretamente na fase móvel por 5 minutos. A validação e estudos de biotransformação foram realizados empregando a cromatografia líquida acoplada à espectrometria de massas (LC-MS/MS). O método foi validado e todos os parâmetros encontram-se de acordo com as recomendações da literatura. O estudo de biotransformação foi realizado com diferentes espécies de fungos e somente os fungos do gênero Cunninghamella foram capazes de biotransformar a risperidona em seu metabólito ativo. O fungo Cunninghamella echinulata foi capaz de biotransformar estereosseletivamente a risperidona no seu metabólito ativo (+)-9-RispOH com excesso enantiomérico de 100% e o fungo Cunninghamella elegans foi também capaz de biotransformar estereosseletivamente a risperidona nos dois enantiômeros da 9-RispOH em diferentes proporções. Os estudos preliminares de catálise assimétrica foram realizados empregando a cromatografia líquida e detecção por UV-Vis, injetando diretamente alíquotas no sistema cromatográfico. Esses estudos mostraram que na condição de reação 1:50:50 (em número de mols, catalisador:oxidante:substrato) houve uma catálise assimétrica da risperidona que demonstrou ser enantiosseletiva para o metabólito 7-RispOH (E1).Risperidone is an atypical antipsychotic drug. Its metabolism yields in two hydroxylated chiral metabolites, 7-hydroxyrisperidone (7-RispOH) and 9-hydroxyrisperidone (9-RispOH). The 9-RispOH metabolite presents the same pharmacologic activity of the parent drug risperidone. This led this drug to be marketed as drug under the generic name paliperidone. Studies have shown differences in the kinetic disposition of the 9-RispOH enantiomers with higher prevalence of the (+)-9-RispOH enantiomer in plasma. Thus, this work aimed to evaluate the ability of some species of fungi and Jacobsen catalysts in the enantioselective (bio)transformation of risperidone into its active chiral metabolite 9-RispOH. To accomplish that, it was developed a separation method to analyze risperidone and its metabolites by chiral high-performance liquid chromatography. This method was employed in enantioselective biotransformation studies and in asymmetric catalysis studies. The chromatographic separation was performed on a Chiralcel OJ-H column using methanol:ethanol (50:50, v/v) plus 0.2% triethylamine as the mobile phase at a flow rate of 0.8 mL min-1. The SPME process was performed by immersing directly a C18 probe fiber in the culture medium during 30 min. The analytes were desorbed from the fiber directly in the mobile phase during 5 min. The method validation and the biotransformation studies were performed by high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The method was completely validated and all parameters were in agreement with the literature recommendations. The biotransformation studies were performed employing different species of fungi and only the Cunninghamella genus was able to biotransform risperidone into its active metabolite. The Cunninghamella echinulata fungus was able to biotransform risperidone into the active metabolite, (+)-9-RispOH, resulting in 100% of enantiomeric excess. The Cunninghamella elegans fungus was also able to biotransform stereoselectively risperidone into (+)- and ()-9-RispOH enantiomers at different rates. Preliminary studies of asymmetric catalysis were performed using high-performance liquid chromatography with UV-Vis detector (HPLC-UV). The aliquots were directly injected in the chromatography system. These studies showed that the reaction with 1:50:50 (catalyst:oxidant:substrate, in number of mols, in this sequence) presented an asymmetric catalysis of risperidone and that showed to be enantioselective to 7-RispOH (E1) metabolite.
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Jakubčeková, Kristína. "Využití různých extrakčních technik pro analýzu výluhů z biouhlu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449333.
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Biochar is a material whose properties, composition and impact on the environment are often discussed nowadays. The reason is its application as a soil conditioner. This leads to the need for qualitative as well as quantitative knowledge of its composition. This diploma thesis focuses on the qualitative analysis of biochar leachates processed by various extraction techniques. To approximate the real conditions, six aqueous mediums with different pH values is used, which a solid sample of biochar is exposed to. The prepared leachates are after that processed by extraction techniques, which are solid phase microextraction (SPME), single drop microextraction (HS-SDME), solid phase extraction (SPE) and liquid-liquid extraction (LLE). Analysis of the extracts was performed by gas chromatography-mass spectrometry (GC/MS). The measurements showed that the HS-SDME technique did not show a response. SPE was a rapid technique, but compared to other techniques, it acquired a smaller range of substances. Liquid-liquid extraction, a time-consuming technique, did not obtain as much analytes as SPME. By comparing these applied techniques, the SPME technique is the best choice. The most common determined analytes were those from the group of ketones and carboxylic acids and their derivatives.
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Chaves, Andréa Rodrigues. "Desenvolvimento da fase extratora SPME de poli(pirrol) e avaliação das técnicas SPME/LC e SBSE/LC para análises de antidepressivos em amostras de plasma." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-21052009-092119/.
Full textAbstract:
A depressão em idosos é uma desordem persistente e recorrente, resultado do stress psicossocial ou efeito de doenças fisiológicas, que podem acarretar a desabilidade do indivíduo, aumento dos sintomas das doenças clínicas, na maior utilização dos serviços de saúde e altas taxas de suicídios.A monitorização terapêutica permite a ndividualização do regime de dosagem, assegurando a eficácia clínica e minimizando os efeitos adversos dos fármacos, prescritos na clínica. Os antidepressivos têm sido monitorados, pois, apresentam intervalos terapêuticos bem estabelecidos, ou seja, a maioria dos pacientes, que apresentam concentrações plasmáticas dentro deste intervalo fixo, tem as desordens psiquiátricas mantidas sob controle e efeitos adversos aceitáveis. Os antidepressivos tricíclicos (ADTs): imipramina, amitriptilina, nortriptilina e desipramina, embora eficazes e ainda muito utilizados, apresentam efeitos adversos, não desejáveis. Os antidepressivos, inibidores seletivos da recaptação de serotonina (SSRIs): citalopram, fluoxetina, paroxetina e sertralina, apresentam eficácia clínica comparável aos clássicos ADTs, mas destituídos dos efeitos adversos associados aos mesmos. Os métodos convencionais, empregados no tratamento de amostras biológicas, para análises de antidepressivos por técnicas cromatográficas, têm sido a extração líquido-líquido e extração em fase sólida. A microextração em fase sólida tem sido empregada em diferentes análises em fluidos biológicos, porém essa técnica apresenta certas limitações como, o número limitado de fases extratoras disponíveis no comércio que sejam adequadas para a análise de compostos não iônicos. A avaliação de novas fases extratoras, mais seletivas, estáveis e de baixo custo tem sido requerida para a análise de fármacos. O interesse no uso de poli(pirrol) (PPY), como fase extratora para SPME, está relacionado às diferentes interações dos fármacos (hidrofóbicas, -, com o grupo funcional polar, troca iônica, ácido-base) aos grupos multifuncionais deste polímero. Sua polimerização pode ser alcançada tanto por oxidação química, quanto por eletrodeposição em meio aquoso ou orgânico. O método eletroquímico apresenta algumas vantagens, tais como: o polímero ou mistura de polimeros podem ser revestidos diretamente em um metal, incorporação de diferentes grupos funcionais, entre outras, a polimerização pode ser eletroquimicamente controlada através da voltametria cíclica. Neste trabalho o poli(pirrol) (PPY) foi eletrodepositado em eletrodo de aço inox e empregado para a microextração em fase sólida dos antidepressivos: paroxetina, fluoxetina, mirtazapina, duloxetina, sertralina e citalopram. As variáveis da eletrodeposição, número de ciclos e contra-íon empregado no processo de eletrodeposição foram otimizadas. Assim como as variáveis SPME: tempo, temperatura, pH e volume de amostra, e tempo e solvente de dessorção; almejando maior sensibilidade para o método SPME-PPY/LC UV proposto. A extração sortiva em barra de agitação (SBSE), técnica recente de preparo de amostras, para a pré-concentração de compostos orgânicos presentes em amostras biológicas, baseia-se na extração estática, através do polímero polidimetilsiloxano (PDMS), no qual ocorre a dissolução (sorção) do analito. Neste trabalho, as técnicas SBSE e cromatografia líquida de alta eficiência com detecção UV (SBSE/LC UV) foram avaliadas para a análise simultânea de antidepressivos em amostras de plasma para fins de monitorização terapêutica. As condições cromatográficas de análise, assim como as variáveis SBSE de extração (tempo, temperatura, força iônica, pH da matriz) e tempo de dessorção, foram otimizadas, visando adequada sensibilidade analítica. A validação analítica foi realizada segundo normas da ANVISA, para ambos os métodos propostos, em diferentes concentrações plasmáticas, as quais contemplam o intervalo terapêutico. Segundo os parâmetros de validação avaliados, os métodos SBSE/LCUV e SPMEPPY/LCUV padronizados poderão ser empregados nas análises dos antidepressivos, para fins de monitorização terapêutica.Depression in the elderly is a persistent and recurrent disorder resulting from psychosocial stress or physiological effect or disease. This condition can lead to disability, cognitive impairment, enhanced symptoms of medical illnesses, increased use of health care services and, increased of suicide rates. Therapeutic monitoring allows individualization of the dose regimen, ensuring clinical effectiveness and minimizing the adverse effects of drugs, prescribed at the clinic. Antidepressants have been monitored because they present well - established therapeutic intervals; in other words, most of the patients present plasmatic concentrations within this fixed range, so that their psychiatric disorders are kept under control and the adverse effects are acceptable. The tricyclic antidepressants (ADTs) imipramine, amitriptyline, nortryptiline, and desipramine, have adverse effects. The selective serotonin reuptake inhibitors (SSRIs) antidepressants citalopram, fluoxetine, paroxetine, and sertraline, are clinically effectiveness as the classic ADTs, but they do not lead to the adverse effects associated to the latter. The conventional methods employed in the treatment of biological samples for analysis of antidepressants by chromatographic techniques have been the liquid-liquid extraction (LLE) and solid phase extraction (SPE) techniques. Solid-phase microextraction (SPME) has been used in various analyses of biological fluids. However, this technique has limitations such as the small number of comemercially available extracting phases that are appropriate for the analysis of non-ionic compounds. Investigation of new extraction phases that are more selective and stable, as well as inexpensive, has been requested for drug analysis. The interest in the use of poly(pirrole) (PPY) as an extraction phase for SPME is related to the different interactions of the drugs (hydrophobic, - , with the polar functional group, ionic exchange and acid-base) with the multifunctional groups on this polymer. The PPY polymerization can be achieved by chemical oxidation or electropolymerization in aqueous solution or organic solvents. The electrochemical method has advantages such as, the polymer or a mixes of polymers can be directly deposited on a metal wire, different functional groups can be incorporated, polymerization can be electrochemically controlled by cyclic voltammetry. In this work poly(pyrrole) was electropolymerized on stainless steel electrodes and employed for the solid phase microextraction of the antidepressants paroxetine, fluoxetine, mirtazapine, duloxetine, sertraline, and citalopram. The electropolymerization variables, the number of cycles and counterion employed in the process were optimized, as well as the SPME variables, time, temperature, pH, sample volume, and desorption solvent; aiming at a better sensibility for the proposed method SPME-PPY/LC-UV. The stir bar sorptive extraction (SBSE), recently established technique for samples preparation, that targets the pre concentration of organic compounds present in biological samples. It is based on static extraction, through the polymeric polydimethylsiloxane (PDMS), where there is analyte dissolution (sorption). In this work, the SBSE technique and liquid chromatography with UV detector (SBSE/LC-UV) were evaluated for the simultaneous determination of antidepressants in plasma samples for therapeutic monitoring purposes. The cromatographic conditions, the SBSE extraction variables (time, temperature, ionic strength and matrix pH), and the dessorption time were optimized for appropriate analytical sensibility. The analytical validation was accomplished according to the norms of ANVISA for both of the proposed methods, in different plasmatic concentrations, which contemplate the therapeutic interval. According to the evaluated validation parameters, the standardized methods SBSE/LC-UV and SPME-PPY/LC-UV can be used in the analyses of antidepressants for therapeutic drug monitoring purposes.
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Mišovie, Zuzana. "Optimalizace SPME při stanovení těkavých sirných látek ve sladu a pivu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-216548.
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Volatile sulphur substances originating during technological processes in malt and beer production can be a cause of various off-flavors and aromas. Their precursors are sulphur-containing amino acids. Sulphur substances play an important role in brewing as even in very low concentrations they can negatively affect total character of beer. Therefore, it is necessary to monitor volatile sulphur substances and their precursors to eliminate undesirable processes. Because sulphur substances occur in beer and raw materials at trace levels, microanalytical methods are used for their detection. This diploma thesis describes the problems of sulphur substances and their determination using the SPME/GC method.
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Silva, Ana Claudia Lemes da. "Tipificação de meis brasileiros por micro-extração em fase solida combinada com cromatografia gasosa (SPME-CG)." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250209.
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Orientador: Fabio AugustoTese (doitorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: O mel é uma das misturas mais complexas de carboidratos produzida pela natureza. É um alimento energético muito importante pelas suas propriedades nutritivas, pelo seu aroma e sabor que dependem fortemente das plantas, flores e condições climáticas presentes na região geográfica onde está localizada a colméia. Não existem metodologias que possibilitem identificação não subjetiva, rápida e confiável da origem floral do mel. O objetivo deste trabalho foi desenvolver uma metodologia que permitisse a identificação da origem floral de méis brasileiros a partir da caracterização química de sua fração de voláteis utilizando micro-extração em fase sólida através do headspace e cromatografia gasosa (HS-SPME-CG). Para o desenvolvimento da metodologia, foram avaliadas 90 amostras de méis brasileiros de vinte origens florais diferentes e variadas procedências geográficas. Onze destas amostras eram unitárias e permitiram apenas um estudo exploratório. Cada tipo de mel apresentou um perfil cromatográfico diferente. Foram identificados potenciais marcadores para os méis de eucalipto (Eucalyptus sp), laranja (Citrus sp), assa-peixe (Vernonia polianthes), cambará (Lantana montevidensis), morrão de candeia (Croton sp) e marmeleiro (Cydonia vulgaris). Os resultados obtidos mostraram que SPME-CG é útil na tipificação de méis e pode eventualmente ser utilizada na sua certificação
Abstract: Honey is one of the most complex mixtures of carbohydrates produced by Nature. It is a very important energetic food for its nutritional properties and for its aroma and flavor that depend strongly on the fauna, flowers and on the climatic conditions in the geographic region where the beehive is located. There are no objective, fast and reliable methodologies for the identification of the floral source of honeys. The objective of this work was to develop a methodology to allow identification of the floral source of Brazilian honeys through characterization of its volatile fraction using headspace solid phase microextraction and gas chromatography (HS-SPME-GC). To develop the methodology, 90 samples of Brazilian honeys of twenty different botanical sources and several geographic locations were employed. Eleven honey types had just one sample, allowing only exploratory studies. Different chromatographic profiles were obtained for honeys from different floral sources. Potential chemical markers were identified for the honeys of eucaliptus (Eucalyptus sp), orange (Citrus sp), assa-peixe (Vernonia polianthes), lantana (Lantana montevidensis), morrão of candeia (Croton sp) and quince (Cydonia vulgaris). The results obtained showed that SPME-GC is useful to identify the floral origin of honey and may eventually be used for its certification
Tese (doitorado) - Universidad
Quimica Analitica
Doutor em Ciências
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Bryant, Yazmina Mercedes. "Interactions of polycyclic aromatic hydrocarbons with mineral surfaces." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/interactions-of-polycyclic-aromatic-hydrocarbons-with-mineral-surfaces(a81215d1-4510-48c8-ad75-a5b6433e80de).html.
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The toxicity and ubiquitousness of PAHs within different terrestrial environments has been an increasing cause for concern amongst environmental scientists in the last decades, in particular regarding their transport within the soil. In an attempt to understand the role of pure inorganic phases in PAH-mobility; experiments exposing mineral soil components with low organic matter content to a PAH-representative were carried out. The systems consisted of four different mineral phases (quartz sand, hematite, iron coated quartz sand and montmorillonite) which were individually exposed to naphthalene in electrolyte solutions prepared at increasing ionic strengths (NaNO3: 0.001 M; 0.01 M; 0.1 M) and pH (4.0 and 5.5). All experiments were conducted over at 24 reaction intervals and at ambient temperature conditions.Mineral geosorbents are traditionally known to be poor PAH-scavengers; in particular when compared to organic, high surface area materials such as activated carbons. On this basis, a preliminary validation experiment (Proof of Concept Experiment) was conducted to test the sensitivity of the selected extraction method (SPME) under complete uptake (activated carbon) and very low uptake (quartz sand) conditions. By extracting and analysing the supernatant after 24 hr of exposure of both sorbents to naphthalene under identical conditions it was concluded that SPME was a feasible extraction technique, yielding good reproducibility (n=3, inter-day RSD%= 11.18% ) even at very low PAH concentrations (0.2 µg / L). The final concentration of naphthalene in the sample supernatant after 24 hours was determined by GC-FID. All samples were extracted using the Solid Phase Microextraction method developed during the Proof of Concept which allowed the rapid extraction of naphthalene in the headspace HS-SPME (extraction time = 3 minutes) using temperature control and ultrasonication as means of agitation. Each sample set included triplicates of blanks and samples as well as calibration standards (in duplicate where possible)Out of the four minerals, only quartz sand and hematite showed a slight tendency towards naphthalene removal from solution; a finding which correlated well with increasing ionic strength. The other two minerals did not show any such trend and the results were deemed inconclusive. In regards to the results for quartz and hematite; the detected uptake was found to be below the sensitivity of the current SPME extraction method according to the error analysis carried out by comparing the sample and blank means whilst accounting for error equal to 1σ. The overlapping of both means in the majority of the samples indicated that both averages were too close to be accurately resolved (due to very low naphthalene uptake). Modifications to the SPME method could improve the reproducibility and decrease the spread of the data; however, this measure would only guarantee higher statistical confidence (95 %) and not higher naphthalene uptake by these minerals. These observations lead to the conclusion that naphthalene was being salted out of solution rather than being removed by sorption; and under these experimental conditions it would not have been possible to detect any real PAH-mineral interaction. In view of this outcome, a different approach was attempted in order to detect surface reactions between the minerals and naphthalene. A series of preliminary (qualitative) surface analysis (AFM, XPS and ATR-FTIR) on pre-loaded mineral specimens were carried out in air at ambient temperature conditions. No naphthalene was positively identified on the surfaces of the studied sorbents. Factors such as molecular size, sorbents characteristics (i.e. roughness, surface charge) and loading conditions impeded the detection of the target molecules. Innovative sample preparation protocols as well as controlled analytical conditions would need to be implemented and evaluated before this kind of analytical tool can be used. The main outcome of this research work was the successful adaptation of SPME to the rapid extraction of naphthalene in electrolyte solutions at optimal and sub-optimal concentration levels; as the proof of concept preliminary experiment showed.
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Rivellino, Sandra Regina. "Desenvolvimento de uma sistematica para SPME-GC com injetores de controle eletronico." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250191.
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Orientador : Fabio AugustoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Mestrado
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Alves, Claudete. "\"Análise de fármacos em fluidos biológicos empregando o acoplamento SPME-LC/MS\"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-18042007-171857/.
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Os métodos convencionais para a determinação de fármacos em fluidos biológicos baseiam-se em técnicas cromatográficas e imunoquímicas. O tratamento prévio de amostras biológicas, o qual abrange as etapas de extração, pré-concentração e clean-up, tem sido requerido nas análises de fármacos, para aumentar a sensibilidade e seletividade analítica. No entanto, nos últimos anos, com o avanço das técnicas instrumentais, diversas técnicas têm sido avaliados para a análise de diferentes fármacos em fluidos biológicos, destacando-se entre elas a Microextração em Fase Sólida (SPME) e a Cromatografia Líquida acoplada a Espectrometria de Massas (LC/MS). A SPME apresenta uma série de vantagens em relação às técnicas de extração tradicionais, ou seja: não requer instrumentação analítica sofisticada, não utiliza solvente orgânico, permite automação das análises, a reutilização das fibras extratoras e integra em um único sistema, a extração, concentração e introdução da amostra no sistema cromatográfico. Neste trabalho, foi desenvolvida uma interface versátil e de baixo custo, que permite o acoplamento das técnicas SPME-LC/MS para análise dos fármacos antidepressivos tricíclicos e anticonvulsivantes. O planejamento fatorial empregado mostrou ser uma ferramenta estatística importante e simples, sendo obtido mais informações com um número menor de experimentos, avaliando não só os efeitos principais como os efeitos de interação de todas as variáveis nas respostas. As condições cromatográficas otimizadas foram adequadas para a análise por LC/MS. Os níveis de detecção alcançados ressaltam a importância e destaque da técnica de cromatografia líquida de alta eficiência acoplada à espectrometria de massas (LC/MS). O método desenvolvido, tanto para os fármacos antidepressivos tricíclicos como para os anticonvulsivantes, mostrou especificidade, precisão, linearidade e limite de quantificação adequado para a análise.Conventional methods used for the determination of drugs in biological fluids are based on chromatographic and immunochemical techniques. The biological samples treatment - which includes extraction, pre-concentration and clean up steps has been required in drugs analysis in order to increase both analytical sensitivity and selectivity. Nevertheless, lately, within the advancements in instrumentation, different techniques have been evaluated for the analysis of different drugs in biological fluids, such as: solid phase microextraction (SPME) and liquid chromatography coupled to mass spectrometry (LC/MS). SPME presents many advantages towards the conventional extraction techniques (soxhlet, LLE and SPE), which include: use of simple analytical instrumentation, analysis automation, reuse of extractor fibers and integration of extraction, concentration and sample introduction in the same chromatographic system. In this work, a versatile and low cost interface was developed, which allows the coupling of SPME-LC/MS techniques to tricyclic antidepressants and anticonvulsivant drugs analysis. The employed factorial design has shown to be a simple and useful statistical tool. With this device more information could be obtained with fewer experiments by evaluating not only the main interaction effects but also the interaction effects of all variables on the results. The optimized chromatographic conditions were adequate for LC/MS analysis. The obtained detection levels highlight the importance of high performance liquid chromatography coupled to mass spectrometry (LC/MS). The developed method, for both tricyclic antidepressants and anticonvulsivants drugs, has presented specificity, accuracy, linearity and adequate limit of detection for this analysis.
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Marín, Carrasco Patricia. "Aplicación de extracción en fase sólida (SPME Y SPE) al control ambiental y biológico de la exposición a agentes químicos en ambientes laborales." Doctoral thesis, Universidad de Murcia, 2014. http://hdl.handle.net/10803/277331.
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El objetivo de este trabajo ha sido estudiar y evaluar la aplicación de la técnica de extracción y microextracción en fase sólida (SPE y SPME) para el desarrollo de metodologías de toma de muestra y análisis que sean útiles tanto al control ambiental como biológico de la exposición laboral a compuestos orgánicos volátiles. Los objetivos específicos propuestos son los siguientes: 1. Desarrollar y evaluar un muestreador pasivo radial basado en SPME para su aplicación al control ambiental de la exposición, estudiando su comportamiento en concentraciones variables en el tiempo, situación que es habitual en ambientes laborales. 2. Desarrollar y evaluar un método de toma de muestra y análisis utilizando SPME que permita llevar a cabo el control biológico de compuestos orgánicos mediante su análisis en la fracción final de aire exhalado. 3. Desarrollar y optimizar un método para el análisis de compuestos orgánicos sin metabolizar en orina mediante SPME. 4. Estudiar y evaluar la aplicación de la técnica de SPE para la toma de muestra en campo y la determinación de estireno sin metabolizar en orina. El dispositivo de muestreo pasivo desarrollado, basado en un prototipo de muestreador en campo de SPME, utiliza como barrera de difusión un cilindro poroso de polietileno y, como adsorbente, una fibra de 80 m de Polidimetilsiloxano/Carboxen. Se ha determinado experimentalmente la velocidad de captación por difusión para los contaminantes estudiados mediante la generación de atmósferas controladas de concentración conocida de dichos contaminantes y se han llevado a cabo ensayos con concentraciones variables. También se ha estudiado la influencia de distintas variables como la temperatura, la humedad relativa, el tiempo de almacenamiento, la velocidad del aire, la difusión reversa y la adsorción competitiva sobre la cantidad de compuesto adsorbido por el dispositivo de muestreo. Se ha estudiado también el comportamiento del muestreador en estaciones de servicio comparado los resultados con los obtenidos con otro muestreador difusivo. El estudio del método de muestreo y análisis de la fracción final de aire exhalado, utilizando la técnica de SPME, ha requerido la generación de atmósferas controladas con diferentes concentraciones de los contaminantes. La muestra se recoge en un bulbo de vidrio cuyos extremos se cierran una vez terminada la exhalación. El método se ha comparado con otro de muestreo de la fracción final de aire exhalado, concentración en adsorbente y análisis mediante desorción térmica. Se ha calculado la precisión y el límite de detección del método. Se ha llevado a cabo un estudio de campo del sistema de medida tomando muestras de tetracloroetileno de un trabajador expuesto en una tintorería, y de benceno, tolueno y xilenos de un grupo de trabajadores expuestos en estaciones de servicio. Entre los factores que pueden afectar a la eficiencia del método de análisis de compuestos orgánicos sin metabolizar en orina mediante SPME se encuentran el tipo de fibra, el tiempo de equilibrio o incubación, la temperatura y el tiempo de extracción, y la presencia o ausencia de sales. Estas variables se han evaluado y optimizado mediante el diseño experimental. Bajo las condiciones óptimas, se ha calculado la precisión y el límite de detección del método. Para estudiar su comportamiento, el método desarrollado se ha comparado con un método automático de espacio de cabeza y se ha participado en un programa de intercomparación. Para la aplicación de cartuchos de SPE para la toma de muestra en campo de orina de trabajadores se ha evaluado en primer lugar el efecto del tipo de adsorbente, el eluyente, el volumen de elución, el flujo de elución, y la adición de metanol en el disolvente de lavado, sobre la recuperación de estireno sin metabolizar en orina mediante el diseño experimental con el fin de obtener las condiciones óptimas. Bajo estas condiciones se ha evaluado la incertidumbre global del método y el límite de detección. Se ha estudiado también la estabilidad del compuesto, tanto en los cartuchos como en viales, para diferentes periodos de almacenamiento. Los resultados obtenidos en este trabajo, aplicando las técnicas de SPE y SPME, indican que las metodologías de toma de muestra y análisis desarrolladas resultan útiles tanto para el control ambiental como para el biológico de la exposición laboral a compuestos orgánicos volátiles. Debido a que son técnicas no invasivas, fácilmente accesibles para laboratorios no especializados y a que facilitan la toma de muestra, el transporte, la conservación y el análisis -gracias a la preconcentración de los analitos de interés- permitirán la aplicación rutinaria de estas herramientas para la evaluación de la exposición laboral.The aim of this work has been to study and assess the application of both solid phase extraction and microextraction techniques (SPE and SPME) to develop methodologies for sampling and analysis for both environmental and biological monitoring of occupational exposure to volatile organic compounds. The specific aims proposed were: 1. The development and assessment of a radial diffusive sampler based on SPME for its application to environmental monitoring of exposure. The behavior of the sampler under concentrations changing with time, a situation that is common in the workplace, was studied. 2. The development and assessment of a SPME method for the biological monitoring of organic compounds by analyzing the final fraction of exhaled air. 3. The development and optimization of a method to analyze unmetabolized organic compounds in urine by SPME. 4. The study and assessment of the application of the SPE technique for field sampling and subsequent determination of unmetabolized styrene in urine. The sampling passive device is based on a prototype SPME field sampler. It uses a porous polyethylene cylinder as the diffusive barrier and an 80 m Polydimethylsiloxane/Carboxen sorbent fiber coating. The determination of the experimental diffusive uptake rates required the generation of controlled test atmospheres having different concentration of toluene and chlorobenzene. The system was used to carry out two fluctuating concentration profiles. The influence of different temperatures, relative humidity, storage time, air velocity, on the sampler behavior was also studied. Back-diffusion and competitive adsorption effects were also checked. A field sampler comparison with respect to a reference sampler was also carried out. The method of sampling and analysis of the final fraction of the exhaled breath using SPME required the generation of controlled atmospheres having different concentrations of the pollutant for the corresponding calibration curves. The sample was collected in a glass tube which ends were closed once the exhalation finished. The tube had an orifice sealed with a septum through which the fiber is inserted. A comparison with other end-exhaled air sampling method, based on sorbent concentration and thermal desorption analysis has been carried out. The precision and the limit of detection of the proposed method have been evaluated. The method has been applied to the determination of tetrachloroethylene from exhaled breath samples of an occupationally exposed person in a cleaning shop, and to the determination of benzene, toluene and xylene from exhaled breath samples from occupationally exposed workers in petrol stations. Parameters affecting the recovery of unmetabolized solvents from urine by SPME, such as type of fiber, extraction temperature, equilibrium time, extraction time, salt addition, and their interactions, were investigated and optimized by experimental design methodology. Under the optimized conditions the precision and the limit of detection were studied. The performance of the method was compared with that of a method based on automatic headspace. The method has been also tested by an intercomparison programme. The effect of sorbent type, eluting solvent, elution volume, elution flow-rate, and the addition of methanol to the washing solvent, on unmetabolized styrene recovery from urine by SPE was evaluated by experimental design methodology to know the optimal conditions. Under these conditions the overall uncertainty and the limit of detection were evaluated. The effect of urine storage conditions, both in cartridges and vials, on styrene recovery has been studied. The sampling and analysis methodologies developed when applying solid phase extraction and Microextraction techniques (SPE y SPME) are useful both for environmental and biological monitoring of occupational exposure to volatile organic compounds. These techniques are easily accessible for a non-specialized laboratory, allowing for an easy and non invasive sampling, as well as an easy transport, storage and analysis. All these mentioned advantages facilitate their routine application to the occupational exposure assessment.
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Souza, Rita de Cassia Zacardi de. "Avaliação das frações voláteis de espécies de Aniba por microextração em fase sólida acoplada a cromatografia gasosa (SPME-GC) e cromatografia gasosa bidimensional abrangente (GC x GC)." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248376.
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Orientadores: Lauro Euclides Soares Barata, Fabio AugustoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: O presente trabalho é apresentado em dois capítulos: o primeiro compreende o desenvolvimento de uma metodologia de diferenciação entre duas espécies de Aniba frequentemente confundidas, Aniba parviflora e Aniba rosaeodora e o segundo compreende o estudo da composição química dos óleos essenciais de Aniba parviflora através de cromatografia gasosa acoplada a espectrometria de massas (CG-EM), cromatografia gasosa com detector de ionização de chama (CG-DIC) e cromatografia gasosa bidimensional abrangente acoplada à espectrometria de massas (CG × CGEM). Para a diferenciação das espécies foi utilizada a avaliação das suas frações voláteis (headspace) através da SPME-CG (Microextração em Fase Sólida acoplada a Cromatografia Gasosa). Foram analisadas um total de 100 amostras de folhas das duas espécies e a diferenciação foi feita através do tratamento quimiométrico dos dados obtidos. Foram analisados ainda óleos essenciais das folhas e da madeira de A. parviflora obtidos por arraste a vapor. O estudo destes forneceu além da composição química, a análise quantitativa dos seus componentes. Por fim foi realizada a comparação da técnica de CG-EM com a inovadora técnica de CGxCG-EM que possibilitou um aumento de 50% na identificação dos componentes e aproximadamente de 80% na separação e detecção. Os resultados obtidos permitem dizer que e possível diferenciar duas espécies botanicamente vizinhas através de técnicas analíticas de maneira objetiva com respaldo estatístico
Abstract: This work consists of two main parts: The first part involves the development of a differentiation methodology between two Aniba species that are often confused with one another, they are Aniba parviflora and Aniba rosaeodora. The second part involves the chemical composition study of Aniba parviflora essential oils through gas chromatography coupled to mass spectrometry (GC-MS), gas chromatography with flame ionization detection (GC-FID) and comprehensive two-dimensional gas chromatography (GC × GC- MS). In the first part, the species differentiation was performed using SPME-GC and chemometric tools for the assessment of their volatile fraction (headspace). A total of 100 different leaf samples coming from distinct individuals of these two species were examined and the differentiation was made based on the SPME-GC chromatograms data that were treated using chemometric tools. In the second part the essential oils of A. parviflora coming both from leaves and wood were also analyzed and its study resulted in the oils chemical composition and in the quantitative analyses of its components. This work provided also a comparison between two techniques, GC-MS and the innovative GCxGC-MS. The later technique allowed an increase of at least 80 % of total components separation and detection and an increase of more than 50 % of the total identified components
Mestrado
Quimica Organica
Mestre em Química
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Sonnette, Alexandre. "Développement d’un système de prélèvement de poussières pour la mise en place d’un outil alternatif de caractérisation de l’exposition humaine aux polluants organiques et aux métaux à la place du biomonitoring." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF072/document.
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Un système de prélèvement de poussière a été mis au point pour étudier l’exposition des personnes aux polluants de l’air intérieur au moyen de prélèvements environnementaux plutôt que par le biomonitoring, plus contraignant. Une nouvelle méthode d’analyse de polluants de l’air intérieur par GC-MSMS a également été développée et permet la quantification d’une centaine de composés organiques dans l’air, dans la poussière, dans la salive et dans les cheveux. Ces deux développements ont été mis à l’épreuve lors d’une étude exploratoire réalisée sur une dizaine de logements en Alsace. Des prélèvements d’air, de poussière, de salive et de cheveux ont été effectués chaque mois chez des particuliers durant un an. Les résultats d’analyses ont été croisés avec les réponses d’un questionnaire sur l’habitat et les habitudes de vie rempli par les participants, et un traitement statistique a été réalisé dans le but de dégager des corrélations entre les différentes matrices. Il s’avère que s’il est aisé d’établir des corrélations entre matrices biologiques et environnementales pour les composés dont l’exposition est majoritairement domestique, comme par exemple pour certains pesticides, ce n’est pas le cas pour les polluants non-spécifiques au logement. Cette étude préliminaire a montré des résultats prometteurs, et ouvre la voie à une campagne de mesure à plus grande échelle visant à mettre en place un modèle statistique d’exposition domestique à des composés organiquesA dust sampling device was developed to assess exposure to indoor air pollutants using environmental samples instead of biomonitoring, which is less practical. A new GC-MSMS analytical method was also developed to quantify one hundred indoor pollutants in dust, air, saliva and hair. Both developments were tested during an exploratory study taking place in Alsatian dwellings. Air, dust, saliva and hair samples were collected each month during one year in these dwellings. Results were crossed with the answers of the residents to a questionnaire about their house and living habits, and statistical data processing was performed with the aim of revealing correlations between environmental and biological matrices. It turns out its easy to establish intra-matrices correlations for compounds exclusively found in the house, like some pesticides, but not for compounds that are non-specifics to the dwelling. This preliminary study shows encouraging results, and paves the way to a large scale study aiming the development of a statistical model of exposure to organic compounds
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Elemia, Freire Constancia Felise, Simon Edin, and Chang Ho Lee. "SPME Method for Chemical Analysis of Heavy Organic Trace Compounds in Synthesis Gas." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277054.
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There currently exists no commercialized method for rapid sampling and analysis of trace tar ingas streams. Solid phase microextraction (SPME) with a polydimethylsiloxane (PDMS) solidphase has been previously investigated as a possible candidate due to its solvent-free natureand reusability. This project set out to deliver a proof of concept study to test whether SPMEcan be sufficiently tuned to analyse trace tar content in syngas below the concentration of 0.1mg/Nm 3 . Due to complications that arose from the Covid-19 pandemic, it was unfeasible tocarry out the practical elements of the project. Instead a concept design for carrying out such astudy has been successfully developed. This design envisions a two-chamber setup able tosample syngas directly from a gasifier at 60 °C and 125 °C respectively and is illustrated in thetext. It utilizes commercially available solvent tubes to cross-check and verify the SPME results.I nuläget finns det ingen kommersiell metod för att snabbt extrahera och analysera spår av tjärkomponenteri gasströmmar. Tidigare har solid phase microextraction (SPME) medpolydimetylsiloxan (PDMS) som fast fas undersökts som en möjlig kandidat då den ej kräverlösningsmedel och kan enkelt återanvändas. Detta projekt hade som mål att bevisa att SPMEkan anpassas tillräckligt känsligt för att analysera spår av tjära i syngas med en koncentration påmindre än 0,1 mg/Nm 3 . På grund av komplikationer som uppstod i samband med Covid-19pandemin var det inte möjligt att utföra den praktiska delen av projektet. Istället så har endesign tagits fram för ett koncept som beskriver hur man kan genomföra den praktiska delen.Designen beskriver en två-kammare lösning som kan användas för att ta prover från syngas somkommer direkt från en förgasare. Proverna tas vid temperaturer om 60 °C och 125 °C för attuppnå maximal känslighet. En uppsättning kommersiellt tillgängliga sorbentrör används för attkontrollera resultaten från SPME.
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HUA, WEIWEI. "Terpenes and terpenoids determination in present of ozone by SPME and GC-MS." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1541.
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Particulate matter air pollution demonstrates adverse human health effect and is one of reasons for the climate change. Monoterpenes are a class of volatile organic compounds (VOCs), which are often present in household products. They can be produced by a variety of plants and belong to biogenic VOC (BVOC) class. Due to the fact that monoterpenes often contain one or more unsaturated carbon-carbon double bonds, they can readily react with ozone, and some of the products form PM. In order to address the potential health problems caused by the use of household products, climate change, and health effects caused by BVOC emissions, an efficient, precise, accurate and environmental friendly analytical sampling and detection method needs to be developed. In this work, a dynamic solid phase microextraction (SPME) sampling method is coupled with gas chromatography (GC)/mass spectroscopy detection for both single monoterpene and complex monoterpene mixture analysis in the presence of ozone. Not only the effects of parameters such temperature, pressure and relative humidity need to be known, but also how the sampling time, flow rate, ozone concentration and monoterpene type affects this analysis method are needed. In consideration of the difference between reactive monoterpenes and nonreactive monoterpenes, several single monoterpenes were selected and smog chamber experiments were conducted. The precision of the sampling method at various sampling times, flow rates and ozone concentrations were compared for both single monoterpenes and monoterpenes mixture. The sampling flow rate had no significant effect on this SPME sampling method. On the contrary, the GC response did have noticeable change when the sampling time and the ozone concentration were varied. A radical scavenger study was conducted and the result indicated that radical scavenger did not have a significant effect on SPME fiber or the precision and accuracy of sampling method.
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Kabir, Abuzar. "Polytetrahydrofuran- and dendrimer- based novel sol-gel coatings for capillary microextraction (cme) providing parts per trillion (ppt) and parts per quadrillion (ppq) level detection limits in conjunction with gas chromatography and flame ionization detection (fid)." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001192.
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Silva, Raquel Gomes da Costa. "Preparo de fibras para microextração em fase solida (SPME) com recobrimentos a base de poliglicois." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250190.
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Orientador: Fabio AugustoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Mestrado
Quimica Analitica
Mestre em Química
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Sattolo, Natalia Meinl Schmiedt. "Análise de estatinas em plasma humano por cromatografia gasosa acoplada à espectrometria de massas utilizando SPME e derivatização in situ no preparo de amostra." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-19052011-101410/.
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A monitorização terapêutica permite a individualização do regime de dosagem, assegurando a eficácia clínica e minimizando os efeitos adversos dos fármacos prescritos. Atualmente, as estatinas têm sido monitoradas, pois, embora eficazes e muito utilizadas, apresentam alguns efeitos adversos não desejáveis. Neste trabalho, as técnicas SPME e cromatografia gasosa acoplada à espectrometria de massas (GC-MS) foram avaliadas para a análise de estatinas (fluvastatina, simvastatina e atorvastatina) em plasma humano para fins de monitorização terapêutica. As condições de extração e derivatização foram otimizadas empregando planejamento experimental e avaliando a influência dos principais parâmetros envolvidos. Para otimização das condições de extração avaliou-se parâmetros como tempo e temperatura de extração, pH, volume de solução tampão e força iônica; e para otimização das condições de derivatização avaliou-se parâmetros como volume de reagente derivatizante, volume de agente pareador iônico e pH. A extração foi realizada utilizando fibras de PDMS-DVB, e a dessorção feita termicamente no injetor do cromatógrafo a gás. O método desenvolvido foi validado segundo normas da ANVISA, apresentando linearidade na faixa de 20 a 500 ng mL-1, precisão com coeficientes de variação menor que 14% e recuperação relativa de 20 a 40%. Concluída a validação analítica, a metodologia proposta foi aplicada em amostras reais de plasma de pacientes em terapia com simvastatina concedidas pelo Laboratório Médico Dr. Maricondi e pela Casa de Saúde de São Carlos.Therapeutic drug monitoring allows individualization of dosage regimen, ensuring the clinical efficacy and minimizing the adverse effects of prescribed drugs. Currently, statins have been monitored; despite they are effective, some statins have undesirable adverse effects. In this work, SPME technique and gas chromatography / mass spectrometry (GC-MS) were evaluated for analysis of statins (fluvastatin, simvastatin and atorvastatin) in human plasma for therapeutic drug monitoring. The extraction and derivatization conditions were optimized using experimental design and evaluating the influence of the main parameters involved in the SPME procedure. To optimize the extraction conditions were evaluated parameters such as time and extraction temperature, pH, volume of buffer and ionic strength, and to optimize the derivatization conditions were evaluated parameters as derivatization reagent volume, ionic agent pareador volume and pH. The extraction was performed using PDMS-DVB fibers, and thermal desorption performed in the injector of the gas chromatograph. The method was validated according to ANVISA, showing linearity in the range 20 to 500 ng mL-1, the precision with coefficients of variation less than 14% and relative recovery from 20 to 40%. The proposed methodology was applied to real samples of plasma from patients on therapy with simvastatin provided by the Laboratório Médico Dr. Maricondi and Casa de Saúde of São Carlos.
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Hancock, Andrew Paul. "Determination and fate of organic pollutants in the environment." Thesis, Northumbria University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367413.
Full textAbstract:
Different sample preparation methodologies were evaluated for the determination of pollutants in different matrices. The methods investigated were chosen on the merits of decreased sample preparation time and low toxic solvent consumption with the aim to provide viable alternatives to more laborious methods, such as, Soxhlet extraction. Techniques were developed to extract and quantify organic pollutants from contaminated soils and water. The results from shake flask extraction of aged phenolic contaminated soils were used in attempt to relate sorption to both the soil, and pollutant properties. This was to help gain an understanding of the transport and fate of phenols in different environmental situations. The partitioning (sorption/desorption) of radiolabelled phenols between aqueous solution and soil was investigated using a modified shake flask technique. This provides additional information which can be related to soil characteristics, hence pertaining to the fate mechanisms involved for phenols in the environment. The results from these investigations suggest that more than one factor contributes to the sorption of phenols in soils.
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Oliveira, Ana Maria de. "Estudos preliminares e aplicações de microextração em fase solida (SPME) combinada com cromatografia gasosa com detecção por emissão atomica." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250205.
Full textAbstract:
Orientador: Fabio AugustoTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Doutorado
Quimica Analitica
Doutor em Ciências
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Ribeiro, Juliano Souza. "Previsão de diferentes atributos sensoriais ligados a qualidade do cafe arabica brasileiro utilizando-se metodos analiticos distintos e ferramentas quimiometricas." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248549.
Full textAbstract:
Orientadores: Marcia Miguel Castro Ferreira, Fabio AugustoTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Atualmente, o café é considerado a segunda bebida mais consumida em todo o mundo, sendo superado somente pela água. Esse consumo representa hoje, cerca de 60 bilhões de dólares anuais, contemplando desde a escolha do grão a ser plantado até o produto final comercializado. No mundo todo, especialistas e pesquisadores buscam meios para reconhecer, valorizar e promover padrões de qualidade para os melhores cafés. Porém, a qualidade da bebida tem se mostrado dependente de vários componentes simultaneamente, e sua avaliação é determinada pela prova ¿de xícara¿, realizada por profissionais experientes na arte de degustar café (provadores). Deste modo, este trabalho visou a construção de modelos quimiométricos de previsão de diversos atributos sensoriais do café arábica brasileiro, a partir da correlação entre o aroma e análises sensoriais. Para isso, a técnica analítica de microextração em fase sólida acoplada a cromatografia gasosa foi utilizada (SPME-GC). Um planejamento experimental realizado com as variáveis experimentais do sistema de SPME indicou as melhores condições para a extração simultânea da maioria dos picos cromatográficos. Com todo o sistema de extração otimizado, foram construídos modelos PLS de previsão para seis atributos sensoriais (acidez, amargor, aroma, bebida, corpo e qualidade global) descritos por provadores, a partir do perfil aromático de amostras de café torrado. Modelos com base em dados espectroscópicos (infravermelho próximo) também foram construídos. Os modelos de regressão PLS gerados a partir dos perfis cromatográficos dos voláteis de cafés arábica torrados e dos dados espectroscópicos previram adequadamente as notas dos seis atributos sensoriais estudados. Os erros de previsão desses modelos foram baixos e compatíveis com os erros médios das notas fornecidas pelos provadores
Abstract: Nowadays, coffee is considered the second most consumed beverage in the whole world, only being surpassed by water. This consumption represents about 60 billion dollars annually, from the choice of the seed to be planted until the final commercialized product. In the entire world, specialists and scientists search for ways to recognize, to promote and to valorize standards of quality for the best coffee beverages. However, the quality of the beverage depends on various compounds simultaneously, and its evaluation is determined by the cup profile carried out by experts in the art of sampling fresh coffee (cuppers). Thus, this work aimed at the construction of chemometric models for the prediction of diverse sensory attributes of Brazilian Arabica coffees from the correlation between their aromas and their sensory analyses. For this, the analytical technique used was solid phase microextraction followed by gas chromatography (SPME-GC). An experimental design carried out with the several variables of the SPME system indicated the best conditions for the simultaneous extraction of the majority of the chromatographic peaks. With the extraction system optimized, PLS prediction models for six sensory attributes (acidity, bitterness, flavour, cleanliness, body and overall quality) described by the cuppers were constructed from the flavour profile of roasted coffee samples. Spectroscopic models based on spectroscopic data (near infrared) were also constructed. The PLS regression models generated from the chromatographic profiles and of the spectroscopic data of roasted Arabica coffee adequately predicted notes of the six sensorial attributes studied. The prediction errors of these models were low and compatible with the average errors of notes supplied by the cuppers
Doutorado
Quimica Analitica
Doutor em Ciências
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Glouzarová, Markéta. "Aromaticky aktivní látky různých druhů čokolády." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216430.
Full textAbstract:
This diploma thesis is focused on the problem of volatile aroma active compounds in chocolate, directly connected with the formation of chocolate aroma. Organoleptic properties of chocolate (aroma and taste) are the most important for evaluating by consumers. In this work four types of plain chocolate: Figaro Sweet Passion 70 % cacao, Figaro plain chocolate, Figaro for cooking and KAUMY chocolate glaze were tested. SPME method (fiber CAR/PDMS 85µm) in conjunction with gas chromatography was chosen for their analysis. Solid phase micro-extraction (SPME) is simple, sensitive, reproducible, rapid and low-cost method for evaluation of key odorant compounds found in cocoa and chocolate products. Using SPME-GC method total 56 aromatic compounds: 14 acids, 9 aldehydes, 8 ketones, 17 alcohols, 7 esters and 1 nitrogen compound were identified and quantified. Taste and aroma are the most important for evaluating of chocolate by consumer. Taste and aroma should be aromatic, pleasant and after used raw material. The single organoleptic properties (appearance, colour, taste, aroma and texture) were observed by sensory analysis using scale and also aroma and taste profiles of samples were created. The assessors were students and staffs faculty of chemistry BUT. The high content of alcohols (methanol, ethanol, propanol, butan-2,3-diol) and fatty acids was found in all types of chocolate , these compounds are probably important components of chocolate aroma. Some detected aromatic compounds doesn´t contribute positively to typical chocolate aroma. Unpleasant odour of these compounds often influences total flavour of chocolate, which was also proved by sensory evaluating.
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Silva, Filho Clóvis Fernandes da. "Determinação de resíduos dos pesticidas pirimetanil, pirimicarbe e buprofezina em águas ambientais por SPME e GCMS." Universidade Federal de Sergipe, 2009. https://ri.ufs.br/handle/riufs/6118.
Full textAbstract:
The aim of the work was to develop method for determining
pyrimethanil, pirimicarb and buprofezin residues in environmental water using solid-phase microextraction and gas chromatography-mass spectrometry. To perform the SPME, a 100 μm polydimethylsiloxane (PDMS) fiber was used for the extraction of the pesticides from water samples. Using univariate optimization process, the main factors affecting the SPME process, such as saline concentration (0 %), stirring rate (900 rpm), pH effect (6.0) and desorption time (7 min.) were studied. The method was validated for the pesticides and the intermediate precision (< 15 %) was shown to be satisfactory. The detection and quantification limits ranged from 0.058 to 0.231 ng L−1. The linearity was studied
in the range of 0.1 - 4.0 μg L−1 obtaining good correlation coefficients (> 0.991). The results obtained in the validation of SPME-GC-MS for the determination of 3 pesticides in water showed that the method is fast, simple, sensitive and very
useful in routine laboratories. The developed method has been used to monitor pyrimethanil, pirimicarb and buprofezin contaminations in superficial water samples collected around irrigated areas of Platô de Neópolis (Neópolis/SE) and
Senador Nilo Coelho (Petrolina/PE). The concentrations of buprofezin and pirimicarb ranged from undetectable to 0.013 μg L−1 and 0.20 to 1.0 μg L−1, respectively. Pyrimethanil was not observed in the samples. The concentrations of the pesticides in the real samples were in accordance with European legislation.O objetivo deste trabalho foi desenvolver um método analítico por microextração em fase sólida (SPME) para a determinação de resíduos dos pesticidas pirimetanil, pirimicarbe e buprofezina em matrizes aquosas ambientais por cromatografia gasosa com detector de espectrometria de massas (GC-MS). Através do planejamento univariado, o procedimento de SPME foi otimizado para possibilitar a extração dos analitos da matriz e os valores ótimos dos parâmetros que influenciam a extração por SPME foram definidos: tipo de fibra (PDMS 100 μm), concentração salina na amostra (0%), velocidade de agitação da amostra (900 rpm), pH = 6, tempo de extração (30 min.) e tempo de dessorção (7 min.). O método foi validado apresentando resultados satisfatórios de precisão intermediária (repetitividade) com R.S.D < 15% para os pesticidas. Os limites de detecção e quantificação variaram de 0,042 e 0,135 μg.L-1 (buprofezina); 0,048 e 0,150 μg.L-1 (pirimetanil) e 0,446 e 1,361 μg.L-1 (pirimicarbe) respectivamente. A curva analítica foi feita utilizando a matriz contendo os pesticidas, de 0,1 a 4,0 μg.L-1 com coeficientes de determinação (R2) > 0,991. Amostras de águas superficiais do Platô de Neópolis-SE e Distrito de irrigação Senador Nilo Coelho em Petrolina-PE, área de irrigação para diversas culturas dos referidos estados, foram analisadas e apresentaram os seguintes resultados para buprofezina < LQ ; 0,14 μg L-1 e < LQ para pirimicarbe, único pesticida não detectado nas amostras foi pirimetanil. O método analítico desenvolvido para extração de pirimimetanil, pirimicarbe e buprofezina em amostras de águas superficiais por DI-SPME/GCMS mostrou-se rápido, sensível, robusto, seletivo, eficiente e com ausência de solventes orgânicos. As concentrações para a buprofezina e pirimicarbe das amostras reais estavam dentro do estabelecido pela legislação européia.
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Pavarini, Daniel Petinatti. "Investigação multidisciplinar da biossíntese de sesquiterpenos bioativos de Lychnophora ericoides (Vernonieae: Asteraceae)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/60/60138/tde-17042015-104826/.
Full textAbstract:
Lychnophora (Vernonieae: Asteraceae) é um gênero micro-endêmico dos \"campus rupestris\" do bioma Cerrado. Os extratos foliares de Lychnophora ericoides (\"Arnica-da-serra\") são usados na terapêutica popular principalmente como analgésico. Seus óleos essenciais são quimicamente ricos em sesquiterpenos. Tais compostos, principalmente os de esqueletos bisabolano e cadinano são produtos biossintéticos do precursor cátion nerolidila. Óleos essenciais de folhas de L. ericoides são bioativos frente a invertebrados do Táxon Acari. Um de seus componentes majoritários, o orto-acetoxi bisabolol, é antinociceptivo em ensaios in vitro. Terpenos são valorizados pela indústria de química fina, haja vista sucessos como Taxol® e Acheflan®. Nossos objetivos em Fitoquímica e Ciências Farmacêuticas se alinham a esse interesse. As terpeno-sintases (TerpS) envolvidas na biossínteses dos compostos são ainda alvo de pesquisas com em Bioquímica. Sua identificação é frequentemente conclusiva em diversos aspectos. Como exemplo, citamos a compreensão dos mecanismos da variabilidade metabólica temporal em espécies nativas e selvagens e os avanços na bioengenharia de Produtos Naturais (PN). Frente a este cenário de fronteira este manuscrito traz um resumo da investigação que objetivou determinar se há diversas isoformas de TerpS operando na produção temporalmente variável de sesquiterpenos bioativos em tecidos foliares de Lychnophora ericoides ou se não as há. Acessamos diferentes amostras selvagens de L. ericoides in situ. Nossos esforços em responder a questão supracitada foram divididos em tarefas, a seguir: (1) Determinação da fração rica em sesquiterpenos inspirada na \"Química Analítica Verde\"; (2) MALDI imaging das proteínas das folhas; (3) Estratégia \"omics\" combinada na identificação e clonagem das TerpS. Visitamos campos de ocorrência (CampO) georreferenciados bem como desconhecidos. O desenvolvimento de método de quantificação por Headspace-SPME permitiu uma comparação rápida e livre de solventes de amostras vegetais mínimas (10 mg). A separação e identificação foi conduzida por Gas Chromatography-Mass Spectrometry (GC-MS). As amostras de Diamantina, CampO mais Boreal de todos, apresentam a maior quantidade de derivados bisabolano. A hidrodestilação do material vegetal excedente ao HS-SPME forneceu óleos essenciais para o isolamento de moléculas. Dados espectrais diversos fundamentam a descrição de um derivado cadinano, o 11-dehidro cadinol, entre outros. O MALDI imaging determinou como exequível a geração de imagens moleculares em folhas de L. ericoides. Foram geradas imagens subepidermais dos íons com m/z que se assemelham a cadinano e bisabolano synthases (CadS and BS). A limitação do emprego da técnica é a determinação previa da massa nominal da proteína nativa. Polyacrylamide Gel Electrophoresis (1D-PAGE) gerou mapas de proteínas separadas por tamanho (A, B, C, e D) (30KDa> m/z <80KDa). A digestão com tripsina das bandas geraram peptídeos para análise em MS. Íons resultantes alimentaram o algorítimo MASCOT. Uma isoforma de germacrano-sintase foi identificada. Prospecção de genes codificadores com o cDNA (Ubiquitina +) determinou uma BS, de comprimento 1600pb, amplificada com primers de design para genes de Helianthus spp. A BS de L. ericoides foi clonada. Concluindo, destacamos dois pontos. (1) O controle enzimático na produção dos sesquiterpenos poderá enfim ser averiguada a nível do transcriptoma. (2) A busca pela produção biotecnológica de PN sofreu um pequeno incremento. Esperamos ter contribuído humildemente na produção sustentável de PN e por conseguinte na preservação da biodiversidade.Lychnophora (Vernonieae: Asteraceae) is micro endemic to \"campus rupestris\" from Brazilian \"Cerrado\". Leaves extracts of Lychnophora ericoides (\"Arnica-da-serra\") are used as folk medicine and mainly as wound healer. Its essential oils were chemically profiled as sesquiterpene-rich. Such sesquiterpenes, both bisabolene-like and cadinane-like carbon skeletons, are derivatives of the nerolidyl cation. L. ericoides leaves essential oils are bioactive against invertebrate Acari. An anti-hypernociceptive ability of its component orto-acetoxy bisabolol was also displayed in vitro. Terpenes are valuable in fine chemistry industry, e.g. Taxol® and Acheflan®. Our phytochemical and pharmaceutical goals are aligned to such an interest. Terpene synthases (TerpS) behind their biosynthesis are target of researches in plant sciences and biochemistry. Identification of TerpS often led to conclusions with diverse impacts. Fundamental concepts on time-dependent shifts of terpene productions in wild type species and advances towards plant metabolites bioengineering are examples. Facing such a frontier field we share here an abstract for the investigation aimed to determine whether there were many isoforms of sesquiterpene synthases operating at leaves tissues in Lychnophora ericoides shift-able production of bioactive sesquiterpenes or whether there were not. We have accessed different in situ samples of L. ericoides. Efforts to answer the above question were sectioned as follows: (1) \"Green-Analytical-Chemistry\" oriented profiling of sesquiterpene-rich fraction; (2) MALDI imaging of proteins in leaves; (3) Combined \"omics\" approaches towards identifying TerpS and gene cloning. We visited both known and novel L. ericoides sites of occurrence (SoO). The development of a quantitative Headspace-Solid Phase Micro Extraction (HS-SPME) method enabled a rapid and solvent-free comparison of minimized samples (10mg). Separation and identification were carried out using Gas Chromatography-Mass Spectrometry (GC-MS). Samples harvested in Diamantina, Northern Most SoO, accumulate the highest amount of bisabolene-like derivatives. Hydrodistillation of leftovers material from HS-SPME yield essential oils used to purify unknown compounds. Based on a diverse spectra collection we report a novel cadinane-like derivative, one 11dehydro Cadinol. MALDI imaging has been determined as suitable for imaging proteins in L. ericoides. In a prospective fashion we generate sub-epidermal images of ions within the m/z frame comprising reported isoforms of both cadinane and bisabolane synthases (CadS and BS). The limitation to its use is the awareness of molecular weight of targeted native proteins. Polyacrylamide Gel Electrophoresis (1D-PAGE) protein mapping determined broad bands of protein distribution in different mass ranges (A, B, C, and D) (30KDa> m/z <80KDa). Bands tryptic digestion, followed by sample clean up, generated peptide pools feasible for MS. The output ions data feed MASCOT algorithm. A germacrane synthase could have been identified. When prospecting encoding genes, viable cDNA (Ubiquitin +) was used. A BS, lengthened 1600bp, was amplified with BS primers designed for Helianthus spp. genes. BS presented in L. ericoides was successfully cloned. In conclusion we headline two topics. (1) Hypothetical enzymatic control of the sesquiterpenes production can now be further investigated at transcriptome level. (2) The seek of a platform that guarantee natural products production in a controlled system has been moved forward. Future production of valued compounds can slightly rely in our humble contribution to support biodiversity conservation.
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Menifuet, Gankam Adeline. "Estrazione della componente volatile di pesche e nettarine a maturazione completa mediante SPME-GC_MS." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
L'italia, dopo la Cina è il più grande produttore di pesche. Al giorno d'oggi le pesche e nettarine sono le varietà maggiormente presenti sul mercato e, quindi, anche quelle più studiate. Lo scopo di questo lavoro è quello di studiare la componente volatile di pesche e nettarine sia a polpa gialla che a polpa bianca appartenenti a varietà antiche e nuove per la determinazione della componente volatile è stata utilizzata la tecnica cromatografica GC (gas-cromatografia) accoppiata ad una spettrometro di massa (MS) microestrazione in fase solida (SPME).
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Braga, Soraia Cristina Gonzaga Neves 1986. "Determinação de off-flavours em carne e gordura suína por GCxGC combinada a SPME." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250188.
Full textAbstract:
Orientador: Fabio AugustoDissertação ( mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: A carne de porco é a proteina mais consumida no mundo. Para ser consumida a carne necessita de um padrão de qualidade e um dos problemas que afeta esta qualidade é o surgimento de odores desagradáveis. Estes odores, conhecidos como boar taint, são causados principalmente pela presença de androstenona e escatol em níveis maiores que 1,00 mg g e 0,25 mg g, respectivamente, em gordura suína. Os métodos existentes para determinação destes compostos são dispendiosos e não geram resultados em tempos satisfatórios para análise de rotina. Neste trabalho foi proposto um novo método para determinação de androstenona e escatol em gordura suína que se baseia na utilização de microextração em fase sólida (SPME) e cromatografia gasosa bidimensional abrangente (GC xGC). Para isso foi realizada uma otimização univariada do tipo de fibra e agente saponificante e posteriormente uma otimização multivariada, envolvendo concentração de saponificante, tempo de saponificação, temperatura e tempo de extração. O método otimizado foi validado sob os parâmetros de limites de detecção e quantificação, linearidade, precisão e exatidão. Para o escatol é possível a quantificação de amostras com quantidades menores que as detectadas sensorialmente (0,25 mg g), com precisão e exatidão, mas para a androstenona, é possível apenas detectar a presença ou não deste analito. Após todo o desenvolvimento e validação do método, este foi aplicado em sete amostras de toucinho cedidas pelo ITAL
Abstract: Pork is the must consumed protein the world. For consumpted, the meat needs a quality standard and one of the problems concerning the quality of pork meat are off-flavours. These off-flavores, called boar taint are caused by the presence of two compounds, skatole and androstenone, in levels superior to 1.00 and 0.25 mg g, respectively in pig fat. In order to determine these flavors is necessary to know the concentrations of androstenone and skatole in pig fat. There are specific methods to analyse these compounds, but they spend a lot of time and require a great number of clean-up steps process. In this work, a faster and cleaner method was proposed to determine the presence of androstenone and skatole in pig fat, based in the solid phase microextraction (SPME) and comprehensive bidimensional gas chromatography (GC xGC). A univariate optimization considering the kind of fibre coating and hydrolysis agent was performed. Later a multivariate optimization was developed to determine the concentration of hydrolysis agent, time of saponification and temperature and time of extraction. The best conditions found for the method were used for its validation. The quantification and detection limits, linearity, accuracy and precision were determined. For skatole it is possible to quantify samples at smaller quantities than those found sensorially (0.25 mg g), with precision and accuracy, but for androstenone the method only detects its presence or absence in the analyte. After all the development and validation of the method, it was implemented with seven samples of pig fat, courtesy of ITAL (Instituto de Tecnologia de Alimentos)
Mestrado
Quimica Analitica
Mestra em Química
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Meyer, Marie. "Exposition fœtale à différentes familles de xénobiotiques en Bretagne : analyse de la matrice méconium." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S178.
Full textAbstract:
Le méconium constitue les premières selles du nourrisson. Cette matrice complexe est analysée dans le cadre du projet « PENEW » (Pregnancy Environment and NEWborn malformations) afin de déterminer si le degré d'exposition fœtale aux xénobiotiques joue un rôle dans la survenue de malformations congénitales. Le but de cette étude était le développement analytique pour la détection et la quantification dans le méconium d’une quarantaine de composés de familles différentes (composés organiques volatils, pesticides, éthers de glycol et les métabolites associés). Trois techniques analytiques différentes et une préparation d’échantillon spécifiques ont été développées pour la détection et la quantification de ces composés dans le méconium. L’application des ces méthodes à 246 échantillons de méconium a montré une exposition fœtale à plusieurs des substances recherchéesMeconium is the earliest stool of newborns. This complex matrix was analyzed through the "PENEW" project (Pregnancy and Newborn malformations Environment) to determine if the degree of fetal exposure to xenobiotics has an influence in the occurrence of birth defects. The objective of this thesis was developed analytical methods for the detection and quantification of several different families of compounds (volatile organic compounds, pesticides, glycol ethers and their metabolites) in meconium. Three different analytical methods and a specific sample preparation have been developed for the detection and quantification of these compounds in the meconium. The application of these methods to 246 meconium samples showed a fetal exposure to several target compounds
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Levy, Marine. "Developing new adsorbents for the passive sampling of organic pollutants in the atmosphere : comparison with existing systems." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAF053/document.
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Les matériaux actuellement utilisés comme capteurs passifs de polluants atmosphériques, la mousse de polyuréthane et la résine XAD®-2, ne sont optimisés ni pour l'adsorption de composés polaires ni pour le captage de particules. Pour remédier à ces limitations, la mousse de carbure de silicium (SiC) est proposée comme alternative. Plusieurs campagnes de mesures ont été mises en place pour comparer SiC et XAD®-2. Les composés recherchés étaient des HAP, des PCB et des pesticides.Une méthode d'analyse combinant ASE, SPE et SPME a été développée et optimisée pour ces polluants. Celle-ci permet d'atteindre de faibles limites de détection et quantification pour les composés recherchés.Les campagnes réalisées montrent que la mousse de SiC est toujours plus efficace que la résine XAD®-2 pour le piégeage de composés particulaires et polaires. De plus, la SiC peut être greffée avec du carbone ou des nanotubes de carbone pour augmenter sa surface spécifique, ce qui la rend également plus performante pour l'adsorption de composés volatils. Les débits d'échantillonnage moyens de la mousse ont été calculés et sont comparable aux valeurs rapportées dans la littérature pour la résine XAD®-2Materials currently used as passive samplers for atmospheric pollutants, polyurethane foam and XAD®-2 resin, are not suited ta trapping polar compounds nor particles. Ta overcome these limitations, silicon carbide (SiC) foam is presented as an alternative. Several sampling campaigns monitoring PAH, PCB and pesticides were done ta compare SiC and XAD®-2. An analytical method coupling ASE, SPE and SPME was developed and optimised for these pollutants. lt allowed low limits of detection and quantification ta be reached for all compounds of interest.Sampling campaigns showed that SiC foam is consistently more efficient than XAD®-2 resin at trapping particulate and polar compounds. Moreover, SiC foam can be grafted with carbon or carbon nanotubes ta increase its specific surface area, which also makes it better at adsorbing volatile compounds. Average sampling rates were calculated for SiC foam and they are comparable ta the values reported in the literature for XAD®-2 resin
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Lima, Paula Feliciano de 1981. "Aplicações de cromatografia gasosa bidimensional abrangente (GCxGC) no estudo de metabólitos voláteis de fungos sapróbios." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250196.
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Orientador: Fabio AugustoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-26T15:52:07Z (GMT). No. of bitstreams: 1 Lima_PaulaFelicianode_M.pdf: 3864135 bytes, checksum: c42784d53cede985603b04a4490ab760 (MD5) Previous issue date: 2014
Resumo: O uso de compostos voláteis produzidos por fungos como parte das estratégias de biocontrole na prevenção de doenças ocasionadas por fitopatógenos vem impulsionando o mercado de biofungicidas. Neste cenário, a análise do metaboloma utilizando apenas uma técnica analítica é por vezes inviável devido à magnitude química dos compostos bem como de sua faixa de concentração. Desta forma, o trabalho utilizou a combinação de HS-SPME (Microextração em Fase Sólida) aliada à técnica GC×GC-qMS (Cromatografia Gasosa Bidimensional Abrangente acoplada à Espectrometria de Massas Quadrupolar) para a obtenção do perfil metabólico volátil inédito de duas espécies de fungos com potencial ação para biocontrole e indução de resistência a fitopatógenos na agricultura, Curvularia sp e Memnoniella sp. Através de modelagem MPCA e HCA foi possível a obtenção de um perfil cinético característico da produção de compostos voláteis das espécies que delimitou o processo de identificação tentativa destes metabólitos. Hidrocarbonetos e álcoois foram responsáveis pela maior produção volátil de ambas as espécies avaliadas, com destaque para a produção de lactonas como y-octalactona, y-hexalactona e y-hexalactona por Curvularia sp e sesquiterpenos como acoradieno, ß-chamigreno, a-chamigreno, ß-elemeno e valenceno por Memnoniella sp. A partir do perfil volátil das espécies, os estudos poderão ser direcionados à ação biocontrole e indução de resistência na agricultura
Abstract: Volatile compounds produced by fungi as part of biocontrol strategies in preventing diseases caused by pathogens has been stimulating the market of biofungicides. So, the analysis of the metabolome using only one analytic technique is sometimes not feasible due to chemical compounds as well as the magnitude of its concentration range. Thus, the study used a combination of HS-SPME technique (Solid-Phase Microextraction) coupled with GC×GC-qMS (Comprehensive Two-Dimensional Gas Chromatography coupled to Quadrupole Mass Spectrometry) to obtain volatile metabolic profiles of two species of fungi with potential for biocontrol activity and induction of resistance to plant pathogens in agriculture, Curvularia sp and Memnoniella sp. Through modeling MPCA and HCA was possible to obtain a typical kinetic profile of volatile compounds from the production of species which delimited the process of identification of these metabolites. Hydrocarbons and alcohols were responsible for most volatile production of both studied species, with emphasis on the production of lactones such as y-octalactona, y-hexalactona e y-hexalactona by Curvularia sp and sesquiterpenes as acoradiene, ß-chamigrene, a-chamigrene, ß-elemene and valencene by Memnoniella sp. From the profile of volatile species, the studies may be related to the biocontrol activity and induction of resistance in agriculture
Mestrado
Quimica Analitica
Mestra em Química
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Borenberg, Fredrik. "Biofiltrering av luft förorenad med terpener : Biofiltration of air polluted with terpenes." Thesis, Växjö University, School of Technology and Design, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-2000.
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Utsläpp av lättflyktiga organiska föreningar (VOC) är ett växande mijlöproblem. Biofiltrering är ett relativt billigt sätt att rena luft förorenad med VOC. Biofiltrering har också en fördel i att föroreningen helt bryts ned och inte endast övergår i en annan form. Rapporten beskriver arbetet kring två biofilter av kolonntyp. Mikroberna som användes kom från främst träflis och jord. Som förorening användes limonen och α-pinen. Analys skedde med gaskromatografi.
Vidare undersöktes om närvaro av silikonolja i filterbädden påverkade resultatet Reningskapaciteten uppgick i filtret utan olja till ca 10 - 12 g/m3.h under de första 25 dagarna i drift och ökade därefter till ca 15 - 20 g/m3.h. Motsvarande data för det oljeberikade filtret är ca 15 - 20 g/m3.h i båda fallen
Emissions of volatile organic compounds are a growing environmental problem. Biofiltration is a relatively cost efficient method to purify air polluted with VOC:s. Biofiltraion also has the benefit of completely degrading the pollutants rather than just transferring them into another phase/form. This report describes the work on two biofilters of column type. The microbes used were extracted from wood chips and soil. As pollutants limonene and α–pinene were used.
Furthermore, it was investigated how the presence of silicone oil in the filter bed affected the filtering results. The filtering capacity in the non oil enriched filter was during the first 25days 10-12 g/m3h and thereafter some 15-20 g/m3h. The efficiency of the oil enriched filter was stable at 15-20 g/m3h.
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Masla, Martin. "Undersökning av extraherbara ämnen från gummi som används i sprutkomponenter med hjälp av SPME och GC-MS." Thesis, KTH, Skolan för kemivetenskap (CHE), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-153488.
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Q-Med är ett medicintekniskt företag som tillverkar medicintekniska produkter, exempelvis produkter som är baserade på gel som innehåller bland annat hyaluronsyra. Gelen är placerad i en spruta som innehåller en gummikolv som är i kontakt med gelen.Idag används allt mer polymera material för olika tillämpningar, bland annat som medicintekniska produkter och läkemedelsförpackningar i läkemedelsbranschen. Q-Meds produkter betraktas som medicintekniska produkter på många marknader. Medicintekniska produkter och läkemedelsförpackningar innehåller ofta material som består av polymerer, exempelvis gummi och plast. På dessa material ställs olika krav så att dessa inte kontaminerar den produkt de är i kontakt med, då detta kan leda till olika negativa konsekvenser, exempelvis toxiska reaktioner i kroppen eller sänkt effektivitet hos läkemedlet/produkten. I och med att polymera material används kan det förekomma olika föroreningar i dessa material, exempelvis tillsatsämnen och reaktionsprodukter. Om dessa substanser läcker ut brukar dessa kallas för ”leachables” och ”extractables” – det finns inga motsvarande namn på svenska. Organiska och oorganiska föreningar är exempel på vad som kan lakas ut ur gummit.Den här rapporten beskriver en studie av gummi (bromobutylgummi) som är i kontakt med en gelprototyp (Prototyp A och Prototyp A-L) för att se vilka föreningar som kan lakas ut från gummit ur perspektivet leachables/extractables. För att ta reda på vilka föreningar som lakas ut från gummit utsattes denna för olika betingelser, som olika pH, temperatur, lösningsmedel, placebolösning och kontakt med produkt. För att kunna analysera vilka föreningar som lakades ut ur gummit i både gasfas och vätskefas användes Solid Phase Micro Extraction (SPME) och GC-MS som analysmetoder. Tre SPME fibrer med olika egenskaper, exempelvis olika polaritet och selektivitet användes för insamling av extraherbara ämnen.Resultaten visar att olika föreningar lakas ut ur gummit. Vid försök att identifiera dessa med ett referensbibliotek för masspektra gav många av dessa föreningar en relativt låg sannolikhet (< 50 %) jämfört med de föreslagna föreningarna. Detta gör det svårt att avgöra om det är en särskild förening som lakas ut eller om det är något liknande ämne som lakas ut. I gasfasen hittades fler föreningar jämfört med vätskefasen. Detta beror bland annat på att det finns fler ämnen som är villiga att gå upp i gasfas på grund av deras affinitet gentemot provet, det vill säga hur villig en förening är att reagera gentemot en annan förening. Två föreningar som dyker upp i de flesta headspace analyserna är 1-Bromo-3-(2-bromoethyl)heptane och butylated hydroxytoulene (BHT).Slutsatsen är att några enstaka föreningar lakas ut från gummit, så som BHT och 1-Bromo-3-(2-bromoethyl)heptane. Vad det gäller de andra föreningarna som lakas ut är det är svårt att avgöra om dessa föreningar verkligen kommer från gummit eller från någon annan källa, exempelvis fiberns omgivning. Detta beror på att SPME-metoden är en känslig metod som kan fånga upp en rad ämnen från sin omgivning. Därför anses det att fler studier måste göras på detta område, fast med en metod som ger mer pålitliga resultat.Q-Med is a medical device company that manufactures medical devices, for instance a product that is a gel containing hyaluronic acid. The gel is placed in a syringe component containing a stopper made of rubber that is in contact with the gel.Today, increasingly more polymeric materials for various applications are used, for example medical devices and pharmaceutical packaging in the pharmaceutical industry. The products of Q-Med are considered as medical devices in many markets. Medical devices and pharmaceutical packaging often contains materials composed of polymers, for instance rubber and plastics. For these materials there are different requirements so that they do not contaminate the product that they are in contact with. Contamination may lead to negative consequences, such as toxic reactions and a reduced effectiveness of the drug/product.Since it is polymeric materials that are used there might be some potential impurities in the material, these pollutants are called leachables and extractables. Organic and inorganic compounds are examples of what can leach out of the rubber.In this report the rubber (bromobutyl rubber) that is in contact with a gel prototype (Prototype A and Prototype A-L) is studied to see if the rubber leaches out some compounds of the perspective leachables/extractbales. To know if the rubber leaches out some contaminates the rubber was exposed to various conditions. For instance; different pH, temperature, solvent, placebo solution and contact with the product. In order to analyze which pollutants leached out of the rubber, Solid Phase Micro Extraction (SPME) and GC-MS where used as analytical methods. Three SPME-fibers with different polarity and selectivity where used for the collection of extractable compounds.The results show that the rubber leaches out different compounds. Many of these have a low probability compared to the spectra of masses in the used reference library. This makes it difficult to determine if there is special compound that leaches out or if it is a similar compound that leaches out. When compared, more compounds were found in the gas phase than the liquid phase. This is partly because there are more compounds that are willing to get up in the gas phase, because of the compounds affinity to the sample, for example different polarity. The two main compounds, which are found in the most headspace analyses, are 1-Bromo-3- (2-bromoethyl) heptane and butylated hydroxytoulene.The conclusion is that some compounds, for instance 1-Bromo-3- (2-bromoethyl) heptane and butylated hydroxytoulene leaches out in the gas phase. For other compounds it’s hard to determine if they come from the rubber or from another source from it’s surrounding. This is because the SPME-method is a sensitive method that can absorb a number of compounds from its surroundings. It is therefore considered that more studies must be done in this area but with another method that give more reliable results.
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Junior, Vinicius Ricardo Acquaro. "Desenvolvimento de diferentes métodos LC-MS/MS para a determinação de fármacos e endocanabinóides em amostras de plasma." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-31052018-223216/.
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Esta tese foi dividida em três capítulos. O capítulo I descreve o desenvolvimento do método Column switching UHPLC-MS/MS para a determinação simultaneamente de fármacos psicotrópicos em amostras de plasma de pacientes esquizofrênicos. A politerapia é uma prática comum no tratamento da esquizofrenia. Portanto, a monitorização terapêutica destes fármacos tem sido realizada para o ajuste das doses e individualização da terapia farmacológica. O método Column switching UHPLC-MS/MS apresentou linearidade na faixa de concentração de 0,025 a 1,25 ng mL-1 com R2 acima de 0,9950 e a falta de teste de ajuste (p > 0,05); precisão com coeficientes de variação inferiores a 12% e exatidão com erro padrão relativo inferior a 14%. Este método foi aplicado com sucesso para determinação de fármacos em amostras de plasma de pacientes esquizofrênicos para fins de monitorização terapêutica. No capítulo II, o desempenho cromatográfico de colunas C18 superficialmente e totalmente porosas com diferentes tamanhos de partícula foi avaliado para a análise de fármacos psicotrópicos por LC-MS/MS e LC-DAD. Com o sistema LC-MS/MS foram avaliados os seguintes parâmetros cromatográficos: altura do prato reduzido vs velocidade linear reduzida, impedância vs velocidade linear reduzida, tempo da corrida cromatográfica vs vazão, pressão vs vazão, resolução, capacidade de pico, assimetria e fator de retenção. Já com o sistema LC-DAD foram avaliados a hidrofobicidade, atividade silanol e impurezas metálicas também foram avaliadas. As colunas com superfície carregada apresentaram maior eficiência cromatográfica para os fármacos em sua forma ionizada. Já as colunas com partículas menores que 2 µm (Cortecs 1,6 µm, Acquity 1,7 µm, e Kinetex 1,7 µm) apresentaram maior eficiência cromatográfica para os fármacos na forma parcialmente ionizada. Os modelos matemáticos gerados foram capazes de prever a pressão e o tempo da corrida cromatográfica em diferentes vazões para todas as colunas. Considerando a eficiência, impedância, resolução, capacidade de pico, fator de retenção e hidrofobicidade, as colunas Cortecs 1,6 µm e Acquity 1,7 µm apresentaram melhor desempenho durante a análise dos fármacos em amostra de plasma. O capítulo III descreve o desenvolvimento e validação dos métodos SPME-UHPLC-MS/MS e Bio-SPME-Nano-ESI-MS/MS para a determinação dos endocanabinóides (AEA e 2-AG) em amostras biológicas. Para a otimização do processo SPME foram avaliadas as fases SPME (C18, C30 e HLB) e os solventes para dessorção (metanol, acetonitrila e isopropanol). Os aditivos modificadores de matriz, como cloridrato de guanidina, ácido trifluoroacético e acetonitrila foram avaliados por planejamento experimental. Os métodos SPME-UHPLC-MS/MS e Bio-SPME-Nano-ESI-MS/MS, com a fase HLB biocompatível, apresentaram para ambos endocanabinóides valores de LOQs de 1 ng mL-1 e 50 ng mL-1, respectivamente. O método Bio-SPME-Nano-ESI-MS/MS permitiu o direto acoplamento da fibra SPME ao espectrômetro de massas via dessorção/ionização nanoeletrospray que resultou em rápida determinação quantitativa dos endocanabinóides em amostras biológicas.This thesis is divided into three chapters. Chapter I describes the development of a column switching UHPLCMS/MS method to determine psychotropic drugs in schizophrenic patients plasma samples simultaneously. Polytherapy is a common practice in schizophrenia treatment. Therefore, therapeutic drug monitoring has been applied to adjust doses and to customize pharmacological therapy. The column switching UHPLCMS/MS method developed here is linear at concentrations ranging from 0.025 to 1.25 ng mL-1 with R2 above 0.9950 and presents lack of fit test (p > 0.05), precision with coefficients of variation lower than 12%, and accuracy with relative standard error lower than 14%. This method was successfully applied to determine drugs in schizophrenic patients plasma samples for therapeutic drug monitoring. In chapter II, the chromatographic performance of C18 superficially porous columns and of C18 fully porous columns with different particle sizes were evaluated for analysis of psychotropic drugs by LC-MS/MS and LC-DAD. Within the LC-MS/MS system, the following chromatographic parameters were assessed: reduced plate height vs reduced linear velocity, impedance vs reduced linear velocity, chromatographic run time vs flow rate, backpressure vs flow rate, resolution, peak capacity, asymmetry, and retention factor. Within the LC-DAD system, hydrophobicity, silanol activity, and metal impurities were also examined. Columns with charged surface displayed improved chromatographic efficiency for drugs in the ionized form. Columns with particles smaller than 2 µm (Cortecs 1.6 µm, Acquity 1.7 µm, and Kinetex 1.7 µm) presented higher chromatographic efficiency for the drugs, which were in their partially ionized form. The generated mathematical models were able to predict the backpressure and the chromatographic run time at different flow rates for all the columns. Considering efficiency, impedance, resolution, peak capacity, retention factor, and hydrophobicity, columns Cortecs 1.6 µm and Acquity 1.7 µm provided the best performance during analysis of drugs in plasma samples. Chapter III describes the development and validation of the SPME-UHPLC-MS/MS and the Bio-SPME-Nano-ESI-MS/MS methods for determination of endocannabinoids (AEA and 2-AG) in biological samples. To optimize the SPME process, SPME coatings (C18, C30, and HLB) and solvents for desorption (methanol, acetonitrile, and isopropanol) were evaluated. Matrix modifier additives, such as guanidine hydrochloride, trifluoroacetic acid, and acetonitrile, were assessed by experimental design. The SPME-UHPC-MS/MS and the Bio-SPME-Nano-ESI-MS/MS methods with HLB biocompatible coating provided LOQ values of 1 ng mL-1 and 50 ng mL-1, respectively, for both endocannabinoids. The Bio-SPME-Nano-ESI-MS/MS method allowed direct coupling of SPME fibers to the mass spectrometer by desorption/ionization nanoelectrospray, which resulted in rapid quantitative determinations of endocannabinoids in biological samples.
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Grote, Christoph. "Entwicklung und Validierung eines automatisierten Systems zur quasi-kontinuierlichen Analyse organischer Wasserinhaltsstoffe mittels Festphasenmikroextraktion (SPME)." [S.l. : s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=95763286X.
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Kanthasamy, Visahini. "Determination of formaldehyde in ambient air using on-fibre derivatization with solid phase microextraction (SPME)." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97054.
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Formaldehyde is an important intermediate in the gas-phase methane oxidation chain and plays an important role in the chemistry of the troposphere by influencing the odd hydrogen budget (HOx = HO + HO2), and thus the Earth's oxidative capacity. The evaluation of the importance of formaldehyde in atmospheric cycles requires accurate and precise measurements of its concentration in the atmosphere. In this work, the concentration of formaldehyde in unpolluted outdoor air will be determined using an on fibre derivatization-solid phase micro-extraction (SPME). This method consists of derivatizing formaldehyde to its pentafluorobenzyl oxime using 1,2,3,4,5-pentafluorobenzylhydroxylamine (PFBHA), extracting using SPME and then analyzing with gas chromatography with flame ionization detector. We herein present an improved methodology for detection of formaldehyde in ambient air using SPME and GC-FID, which gives a detection limit of 100-300 pptv, for our rapid, portable and environmentally benign technique. The developed methodology was used to measure the formaldehyde mixing ratios in chemistry labs (9.28 ± 0.26, 12.36 ± 0.11 ppbv), library (11.75 ± 0.57 ppbv), and basement of a building (6.79 ± 0.010 ppbv) and in a campus terrain (7.17 ± 0.040 ppbv). We observed a diurnal variation in the mixing ratios of formaldehyde measured in the city of Montreal. The implications of our results will be herein discussed.Le formaldéhyde joue un rôle important en tant qu'intermédiaire dans l'oxydation du méthane dans la phase gazeuse ainsi que dans les réactions chimiques de la troposphère en influençant le budget de radicaux hydroxyle et donc la capacité oxydative de l'atmosphère. Afin d'évaluer l'influence du formaldéhyde sur les cycles atmosphériques, la concentration atmosphérique exacte est requise et ce nécessite une méthodologie précise pour prendre des mesures. Dans ce travail la concentration du formaldéhyde dans l'atmosphère non polluée est mesurée à l'aide d'une fibre de micro extraction phase solide (SPME). Cette méthode consiste à dérivatiser le formaldéhyde en son oxime de pentafluorobenzyl avec du 1,2,3,4,5-pentafluorobenzylhydroxylamine (PFBHA), suivi par l'extraction et l'analyse par chromatographie phase gazeuse équipé d'un détecteur à ionisation de flamme (FID). Nous présentons une méthodologie améliorée pour détecter le formaldéhyde dans l'air ambiant à l'aide de la SPME et du GC-FID ; nous achevons une limite de détection de 100-300 pptv. La méthodologie a été utilisée pour déterminer les taux de formaldéhyde dans des laboratoires de chimie (9.28 ± 0.26, 12.36 ± 0.11 ppbv), dans une bibliothèque (11.75 ± 0.57 ppbv), dans le sous-sol d'un bâtiment (6.79 ± 0.010 ppbv), et sur un terrain au sein de l'université (7.17 ± 0.040 ppbv). Des mesures prises en 2009 au mois de juillet montrent que le taux atteint dans la journée et la soirée étaient de 8-12 ppbv et de 5-7 ppbv, respectivement; la méthodologie permet également de discerner les variations temporales.
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Urruty, Louise. "Les pesticides dans les vins : étude de la microextraction en phase solide (SPME) des résidus." Bordeaux 1, 1997. http://www.theses.fr/1997BOR10557.
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Les nombreux avantages de la microextraction en phase solide (spme) nous ont amene a choisir cette nouvelle technique pour developper une methode de determination des residus de pesticides dans les vins. Un protocole d'extraction de douze pesticides presentant un interet viti-vinicole a ete mis en place dans l'eau. L'influence de certains composes endogenes du vin (ethanol, acide tartrique, ph, composes phenoliques et sucres) sur l'efficacite d'extraction, ont conduit a l'elaboration d'un modele analytique. Enfin, des applications au vin ont permis, d'une part, de verifier l'applicabilite de notre methode et, d'autre part, de confronter, pour la procymidone, les resultats donnes par cette methode avec ceux obtenus par une methode elisa.
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Chmelka, Milan. "Stanovení těkavých organických látek metodou "head space - SPME" v reálných vzorcích povrchové a pitné vody." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216373.
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Volatile organic compounds are mostly found in the water as contaminants of human origin. Theoretical part of the thesis is focused on characteristic and occurence of volatile compounds. At the same time it also deals with possibilities of their qualification and quantification. Extensive description have been focused to static head-space technique combine with solid phase microextraction. The objection of the experimental part was gaining experience with operating the device/instrument used for measuring. After locality selection could begin sampling and their analysis.
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Claypoole, Sherri L. "Quantitation of 3-alkyl-2-methoxypyrazines in Grape Juice and Wine via SPME-GC/MS." Youngstown State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1279827076.
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Sheehan, Emily Moore. "Time-weighted average solid-phase microextraction (TWA-SPME) for in-planta detection of chlorinated solvents." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Sheehan_09007dcc8067c9a4.pdf.
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Thesis (M.S.)--Missouri University of Science and Technology, 2009.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed June 16, 2009). Includes bibliographical references (p. 63-66).