Dissertations / Theses: 'Gc, Gc-Ms'

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Nakovich, Laura. "Analysis of Biogenic Amines by GC/FID and GC/MS." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/35027.

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Low levels of biogenic amines occur naturally, but high levels (FDA sets 50 ppm of histamine in fish as the maximum allowable level) can lead to scombroid poisoning. Amines in general are difficult to analyze by Gas Chromatography (GC) due to their lack of volatility and their interaction with the GC column, often leading to significant tailing and poor reproducibility. Biogenic amines need to be derivatized before both GC and HPLC analyses. The objective of this research was to develop a relatively fast, reproducible method to derivatize and quantitate biogenic amines in fish at trace levels using GC/FID. The derivatizing reagent used in the experiments was propyl chloroformate, useful for aqueous samples. To confirm the identity of six derivatized biogenic amines GC/MS was used. To our knowledge no reference spectra for these derivatives has been published. It was concluded that best results are obtained using a Cold-On-Column (C.O.C.) inlet with a short column (15 meters), thick film stationary phase (ZB-5, 1.00Î¼m df), and with recommendations to cut 40 cm from the inlet end of the column every 25 injections when using C.O.C. Duplicate samples of Atlantic Salmon were analyzed on days 0, 3, and 5. Levels of histamine were below 50 ppm for days 0 and 3, but day 5 showed average levels of 160 pm (cadaverine), 1000 ppm (histamine), and 350 ppm (tyramine). Good precision of six amine stardards at 50 ppm was shown: heptylamine 5.2%, putrescine 5.6%, cadaverine 5.0%, histamine 9.9%, tyramine 5.1%, and spermidine 6.2% RSD.
Master of Science

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De, Vos Betty-Jayne. "Gas chromatography coupled with ion trap mass spectrometry (GC-MS and GC-MS-MS) - for arson debris analysis." Diss., Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-02082006-160506.

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Sýkora, Richard. "Využití GC/MS při analýze léčiv." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-216709.

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This diploma thesis is based on the current issue of the presence of pharmaceuticals in various components of the environment. Concerning the contamination by residues of pharmaceuticals the most affected environment is the aquatic environment where these substances leaks especially from wastewater treatment plants, which eliminate them during the cleaning process only partially. This work is focused on the selected group of pharmaceuticals, non-steroidal anti-inflammatory drugs (salicylic acid, ibuprofen, caffeine, naproxen, ketoprofen, diclofenac) in waste water. For analysis purposes two types of sampling were used and compared: the conventional spot sampling of wastewater and the sampling using passive samplers POCIS. The sampling took place at the inflow and outflow of the wastewater treatment plant in Brno Modřice. The solid phase extraction (SPE) using Oasis HLB columns was used as the extraction method. Extracted sample was derivatized then. Derivatization agents were: MSTFA (N-methyl-N-(trimethylsilyl)trifluoroacetamid) and BSTFA (N, O-bis(trimethylsilyl) trifluoroacetamid). The final analysis was performed using gas chromatography with mass spectrometric detection Time-of-Flight (GC/TOF-MS).

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MacGillivray, Tanya Frances. "Analysis of lichens under environmental stress using pyrolysis-GC-MS and pyrolysis-GC-FID." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0018/MQ54933.pdf.

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Silva, Rosselei Caiél da. "Comparação entre métodos cromatográficos, empregando GC-ECD, GC-FPD E GC-MS, e espectrofotométrico para determinação de ditiocarbamatos em alface." Universidade Federal de Santa Maria, 2005. http://repositorio.ufsm.br/handle/1/10469.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Brazil is the third largest market for pesticide sales in the world, with almost 400 active ingredients registered in the country, including five dithiocarbamates. This pesticide class consists of very important protective nonsystemic fungicides with broad-spectrum activity registered for the control of fungal deseases on a large variety of crops. Due to its low acute toxicity, combined with strong action, low-cost production and low environmental persistence, the total amount used of these compounds used is still increasing world-wide. Many methods to determine dithiocarbamates are based on acid hydrolysis in the presence of stannous chloride and analysis of the evolved CS2 by different techniques. In the present work, three chromatographic methods were validated for the quantification of dithiocarbamates residues in lettuce using Gas Chromatography with Electron Capture Detection (GC-ECD), Flame Photometric Detection (GC-FPD) and Mass Spectrometry (GC-MS), and these three methods were compared with a spectrophotometric method.The experimental conditions for the chromatographic analysis were: capillary column CP-Sil 8 CB (50 m x 0.32 mm i.d. x 1.2 μm film thickness); temperature program column oven: 45 oC (1 min) - 10 oC min-1 to 250 oC (0 min); flow-rate of the carrier gas (Helium) 2 mL min-1; volume of injection 4 μL, with split 1:10 for GC-ECD and GC-MS and 1:15 for GC-FPD; temperature of the detector was 300 oC for ECD and 250 °C for FPD. The transferline and trap were heated to 230 °C and the manifold to 120 °C. The spectrophotometric analysis was done in 435 nm, after complexation of the CS2 with diethanolamine and copper. In the validation study of the methods, the following parameters were assessed: detection limit (LOD), quantification limit (LOQ), precision (under repeatability and reproducibility conditions) and recovery. Method LODs in the sample were 0.01 mg CS2 kg-1 and 0.28 mg CS2 kg-1 and LOQs were 0.02 mg CS2 kg-1 and 0.4 mg CS2 kg-1 for chromatographic and spectrophotometric methods respectively. The calibration curves were linear with correlation coefficients r2> 0.99. Acceptable precision with RDS% between 2.8 and 15.9 was obtained. The recoveries ranged from 87.7 to 107.4%. The results obtained in the validation step allow us to conclude that the methods are quite appropriate to determine residues of dithiocarbamates in lettuce. However, the chromatographic methods have shown a lot of advantages such as to be more sensitive, simple and faster than the spectrophotometric method. Beside, the sample preparation can be done simultaneously for a great number of samples and in a simplified way.
O Brasil é o terceiro maior mercado mundial de pesticidas, com aproximadamente 400 ingredientes ativos registrados no país, incluindo cinco ditiocarbamatos. Esta classe de pesticidas é composta por importantes fungicidas de ação não sistêmica e de amplo espectro de atividade empregados para controle de fungos em uma grande variedade de culturas. Devido a baixa toxicidade, combinado com forte atividade, baixo custo de produção e baixa persistência ambiental, a quantidade destes compostos tem aumentado no mundo inteiro. Muitos métodos para determinar ditiocarbamatos estão baseados na hidrólise ácida, em presença de cloreto de estanho II, e análise do CS2 gerado por diferentes técnicas. Neste trabalho, foram validados três métodos cromatográficos para a quantificação dos resíduos de ditiocarbamatos em alface empregando Cromatografia Gasosa com Detecção por Captura de Elétrons (GC-ECD), Detecção Fotométrica de Chama (GC-FPD) e Detecção Espectrométrica de Massas (GC-MS), e comparou-se com o método espectofotométrico. As condições para as análises cromatográficas foram: coluna capilar CP-Sil 8 CB (50 m x 0,32 d.i x 1,2 μm de espessura do filme); programa de temperatura do forno da coluna: 45 °C (1 min) com incremento de 10 °C min-1 à 250 ° C (0 min); vazão do gás de arraste em 2 mL min-1; volume de injeção de 4 μL com split 1:10 para GC-ECD e GC-MS, e 1:15 para GC-FPD; temperatura do ECD foi 300 °C e do FPD de 250 °C. O transferline e o trap foram aquecidos a 230 °C, e o manifold a 120 °C. A análise espectrofotométrica foi realizada a 435 nm, após a complexação do CS2 com dietanolamina e cobre. Para a validação dos métodos seguiram-se os seguintes parâmetros: limite de detecção (LOD), limite de quantificação (LOQ), linearidade, precisão (repetitividade e precisão intermediária) e recuperação. Os LODs na amostra foram 0,01 e 0,28 mg CS2 kg-1, e os LOQs foram 0,02 e 0,4 mg CS2 kg-1 para os métodos cromatográficos e espectrofotométrico, respectivamente. As curvas analíticas apresentaram r2> 0,99. Os estudos de precisão apresentaram resultados aceitáveis, com valores de RSD% entre 2,8 e 15,9. As recuperações foram de 87,7 a 107,4%. Através dos resultados obtidos na validação, pode-se concluir que os métodos são apropriados para determinar resíduos de ditiocarbamatos em alface. Entretanto, os métodos cromatográficos têm apresentado várias vantagens como elevada sensibilidade, simplicidade, além de serem mais rápidos que o método spectrofotométrico, pois é possível realizar o preparo de um grande número de amostras simultaneamente.

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Silva, Rosselei Caiél da. "Métodos individual e multirresidual para determinação de pesticidas em grãos e derivados por GC-PFPD, GC-ITD-MS e LC-MS/MS." Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/4212.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Due to the complexity of grains like soybean, corn and rice, and the very low pesticide concentration expected for these samples, it is really necessary to develop efficient and reliable analytical methods to identify and quantify their residues. The possibility to perform the determination of a large number of pesticides in just a single chromatographic analysis is the major advantage of the multi-residue methods. However, there are important compounds that are not possible to be analyzed together, like the dithiocarbamates (DTC). For that, is so important to develop and validate single methods. Due to low acute toxicity, combined with strong action, low-cost production and low environmental persistence, the dithiocarbamates are still using worldwide. The first part of this study reports a sensitive analytical single method suitable for the quantitative analysis of DTCs in soybeans, rice and corn, using GC-PFPD and GCITD- MS. For the method validation studies, the following parameters were assessed: detection limit (LOD), quantification limit (LOQ), precision (repeatability and intermediate precision) and accuracy, via recovery experiments at 0.05, 0.1 and 0.5 mg CS2 kg-1 spiking levels. For soybeans is necessary a clean-up step due the high fat content in that crop, because of it, same sorbents (Aluminum oxide, Florisil®, Silica, PSA, C18 and C18OH) were tested and the best results were obtained applying silica gel. For the extraction procedure, an amount of sample was weighed and water added. The spike solution (thiram) was added to the sample, 25 mL of isoctane and 150 mL of tin (II) chloride solution in hydrochloric acid were added. The bottles were closed immediately and heated for 1 h in a water bath at 80 °C, under shaking. After cooling, 2 mL aliquot of the upper organic layer of each bottle was pipetted into a tube containing 50 mg of silica gel, for the clean-up step. The analytical curves were linear from 0.02 to 1.0 mg CS2 L-1 with determination coefficients (r2) higher than 0.99 for both detection systems and to all crops. Method LOD and LOQ values were 20 and 50 μg CS2 kg-1, respectively, for soybeans and corn. For rice LOQ was just 40 μg CS2 kg-1. Very good precision was obtained with RSD between 1.8 and 7.9% and recoveries from 67 to 103%, for all matrices. The results obtained in the validation step allow us to conclude that both chromatographic detection systems are appropriate to determine residues of DTCs in grains. The second step was to develop and validate a method for the analysis of 75 pesticides in corn grain and breakfast cereals using LC-MS/MS, ESI positive mode. The extraction procedure was the modified QuEChERS method, however, excluding the dispersive SPE clean-up step. To that end, milled and homogenized corn grain and breakfast cereals with water were spiked with 75 pesticides, at 3 spiking levels (10, 20 and 50 μg kg-1, n=6), plus the procedure internal standard (quinalfos). A volume of 10 mL of acetonitrile with 1% acetic acid was added and the tubes were vigorously shaken for 1 minute. The tubes were uncapped, anhydrous magnesium sulfate were added, the shaking procedure was repeated and the extract was centrifuged at 4000 rpm, for 4 min. The upper layer of the extracts was transferred to chromatographic vial, containing 0.5 mL of the instrumental internal standard (propoxur) in methanol. The linear range wasevaluated and validated between 0.1 and 50 μg L-1 of the analytical curves (7 concentrations, n=6). Also LOD, LOQ, matrix effect, as well as precision (as RSD%) and accuracy (as recovery), for 75 pesticides, were studied The LOD were calculated based on practically realized repeatability RSD. To determine the precision, accuracy and LOQ, blank samples were spiked at 10, 20 and 50 μg kg-1. The results showed recoveries between 70 and 120% and RSDs <20% for the majority of the pesticides studied, even at the lowest level. As expected, the matrix effect did not have influence on the results, and the values of LOD and r2 were considered as satisfactory for the purpose of this study.
Devido a complexidade de matrizes de grãos como soja, milho e arroz, e das baixas concentrações dos pesticidas presentes, há uma grande necessidade de desenvolvimento de métodos analíticos eficientes e confiáveis para a identificação e quantificação desses resíduos. A maior vantagem de um método multirresidual é a possibilidade de se determinar um grande número de pesticidas na mesma análise cromatográfica. Entretanto, alguns compostos, devido suas características específicas, não podem ser determinados em conjunto com outros analitos. Assim, é importante que também se desenvolva e valide métodos individuais de análise, comoo método para determinação de ditiocarbamatos (DTC). Os DTC apresentam baixa toxicidade aguda, combinado com forte ação fúngica, baixo custo e baixa persistência ambiental, por isto, estes continuam sendo largamente utilizados na agricultura. Na primeira parte deste estudo, foi desenvolvido um método individual de análise para determinar DTC em soja, arroz e milho, empregando GC-PFPD e GC-ITD-MS. Para o estudo de validação do método, os seguintes parâmetros foram avaliados: limite de detecção (LOD), limite de quantificação (LOQ), precisão e exatidão, através do estudo de fortificação e recuperação, nas seguintes concentrações: 0,05; 0,1 e 0,5 mg CS2 kg-1. Para a determinação de ditiocarbamatos, adicionou-se um volume de água à amostra (arroz, milho e soja). Fortificou-se com solução de tiram, adicionou-se 25 mL de isoctano e 150 mL de solução de SnCl2 em HCl. Os frascos foram fechados e levados ao banho de agitação, a 80 °C, por 1 hora. Após o resfriamento, 2 mL da fase orgânica foram transferidos para outro frasco contendo 50 mg de sílica gel, para a etapa de purificação. As curvas analíticas foram lineares na faixa de 0,02 a 1,0 mg CS2 L-1, com coeficiente de determinação (r2) maior do que 0,99, para todas as culturas, nos dois sistemas de detecção. O LOD e LOQ do método apresentaram os mesmos valores para soja e milho, sendo, respectivamente, 20 e 50 μg CS2 kg-1. Já o LOQ para arroz foi de 62 μg CS2 kg-1, devido a menor quantidade de amostra utilizada. Observa-se, desta forma, que os valores de LOQ encontrados são inferiores ao limites máximos de resíduos permitidos (LMR) pela legislação nacional, que são de 0,3 mg CS2 kg-1 para soja e milho, e de 3 mg CS2 kg-1 para o arroz, indicando que os métodos podem ser utilizados para este tipo de determinação. A precisão mostrou-se muita boa, com valores de RSD entre 1,8 e 8,7%, e recuperações de 63 a 103%. Assim, os resultados obtidos pela validação do método permitem concluir que ambos os sistemas cromatográficos são adequados para determinar DTC em grãos. A segunda etapa do estudo foi validar o método multirresidual para determinação de 75 pesticidas em milho (grão) e cereais matinais, empregando LCMS/ MS, no modo ESI positivo. O procedimento de extração foi baseado no método QuEChERS, com algumas modificações. Grãos de milho e cereais matinais foram moídos e homogeneizados, e um volume de água de, respectivamente, 7,5 e 8 mL foi adicionado. Após, executou-se a fortificação com uma solução contendo os 75 pesticidas do estudo, nos níveis de concentração de 10, 20 e 50 μg kg-1. Um volume de 10 mL de solução de ácido acético 1% em acetonitrila contendo o padrão interno quinalfós foi adicionado, e os tubos agitados por 1 minuto. Os tubos foram abertos e MgSO4 anidro adicionado seguido de agitação e centrifugação a 4000 rpm, por 4 minutos. Um volume de 0,5 mL da fase superior foi transferido para vial contendo 0,5 mL do padrão interno propoxur em metanol. Os resultados obtidos para esta validação foram satisfatórios. Recuperações entre 70 e 120%, com RSD <20% foram obtidos para a maioria dos pesticidas estudados, nas duas matrizes, conforme recomendando pela SANCO (2009). Conforme esperado em LC-MS/MS, o efeito matriz não influenciou os resultados.

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Lineberry, Quentin. "Determination of Carbon Nanotube Modification by TG-MS and Pyrolysis-GC/MS." TopSCHOLAR®, 2004. http://digitalcommons.wku.edu/theses/534.

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Uniform dispersion of carbon nanotubes (CNTs) has been one of the major impediments to the full development of the incredible suite of properties offered by CNTs, specifically single-walled carbon nanotubes (SWNTs). However, investigators at NASA Langley and the National Institute of Aerospace Research have recently obtained (SWNTs) that are soluble in select solvents, including THF, DM Ac, and ODCB. The SWNTs were exposed to reagents used in cited fullerene modification chemistry in an attempt to produce soluble SWNTs. Upon further examination, it was determined that the intended functionalization had not occurred, and some other phenomenon was responsible for the SWNTs solubility. Determination of what was imparting solubility to the SWNTs was the goal of this project. The two evolved gas analysis (EGA) techniques used during this project were thermogravi me try-mass spectrometry (TG-MS) and pyrolysis-gas chromatography/mass spectrometry (GC/MS). Samples were heated while the gasses evolved were monitored to determine their identities. The soluble SWNTs were less stable than the non-soluble SWNTS. In addition, they also had much more complicated degradation schemes as evidenced by the additional mass loss events seen in the TG-MS data. Based on the data, some form of methoxide or methanol is imparting solubility to the SWNTs.

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Kaspar, Hannelore. "Amino acid analysis in biological fluids by GC-MS." kostenfrei, 2009. http://www.opus-bayern.de/uni-regensburg/volltexte/2009/1316/.

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Hamblin, D'Nisha D. "Exhaled Breath Analysis of Smokers Using CMV-GC/MS." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2605.

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The aim of this research was to demonstrate the potential of the novel pre-concentration device, capillary microextraction of volatiles (CMV), for breath analysis. The CMV offers dynamic sampling of volatile organic compounds with its simple coupling to a GC inlet for GC/MS analysis, avoiding expensive thermal desorption instrumentation needed for sorbent tubes, as well as an increased surface area over a single SPME fiber. CMV collectively identified 119 compounds in the breath of 13 self-reported smokers and 7 nonsmokers. The presence and intensity of twelve compounds were used to classify all the nonsmokers 100% of the time using Principal Component Analysis to elucidate the groupings. In some cases, nicotine was not detected in smokers and they were confused with the nonsmokers. Nicotine was detected in the breath of 69% of smokers with an average mass of 143 ± 31 pg for cigarette smokers from the approximate 5 L sample of breath collected. The successful use of the CMV sampler and preconcentration of breath to distinguish between smokers and nonsmokers served as a proof of concept for future applications of the CMV for detection of marijuana smokers’ breath for impaired driver management.

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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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Dursun, Hayrettin. "Determination Of The Postexplosion Residues Of Nitro Group Containing Explosives In Soil With Gc-ms And Gc-tea." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12609014/index.pdf.

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There is an increase in bombing assaults in recent years in our country. Determining the explosive material used in these cases by the quick and correct analysis of the evidence obtained after the explosions, is an important starting point for the investigations which are done to reach the perpetrators. The forensic chemistry investigations have to be correct, exact and rapid in order to reach the right criminal. In this study, the Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Thermal Energy Analyser (GC-TEA) methods which are being used for the determination of the explosive materials&rsquo
residues used in bombing attacks are optimized with the standard solutions of 2,4,6-Trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazocyclohexane (RDX) and standard mixture solution. The two methods were compared by analysing the postexplosion soil samples. Also an efficient and applicable sample preparation procedure was developed. The results showed that both methods are efficient and sensitive for the postexplosion investigations. It is seen that GC-TEA has lower detection limit and simple chromatograms due to its selectivity against only nitro group containing explosives. However it is concluded that there is a need for a reliable and sensitive method like GC-MS which provides identification and library search, for the determination of the organic components which can not be identified with GC-TEA

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O'Mahoney, T. Karl P. "An investigation of perfluorocarbons and bromofluorosilanes : pyrolysis, GC-ECD, GC-MS, FTIR and microwave spectroscopic studies and analysis." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259467.

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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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Facco, Janice de Fátima. "Agrotóxicos em milho: otimização e validação de método Multirresíduo empregando GC-MS/MS." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/10530.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Due to the complexity of its matrix, more efficient methods have been studied for the determination of pesticide residues in maize. The use of QuEChERS method coupled to low temperature clean up technique has showed advantages to reduce lipids during sample preparation in matrix with high fat content. It was optimized and validated in this study a multiresidue method for the determination of pesticides in maize employing QuEChERS and GC-MS/MS. The extraction procedure was optimized though the factorial design, and consisted in weighing 2.5 g of sample and adding 10 mL of ultrapurified water followed by vortex shaking for 1 min. After this, It was added 10 mL of acetonitrile and the tube was stirred for 1 h in a platform shaker at 200 rpm. Partition step was performed using 1 g of NaCl and 6 g of MgSO4, followed by manual shaking for 1 min and centrifugation at 3400 rpm for 8 min, at 10 ºC. An aliquot of 4 mL of the extract was transferred to a 15 mL tube for clean up step at low temperature for 12 h around -20 ºC. Finally, another clean up stage was realized applying dispersive SPE, 1 mL of the extract was transferred to a tube containing 150 mg of MgSO4, 50 mg of C18 and 50 mg of PSA followed by shaking and centrifugation. The final extract was filtered and analyzed by GC-MS/MS. Analytical parameters evaluated in this work were linearity of the analytical curve, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy and matrix effect for the 12 compounds studied. The method showed efficient, with recovery results in a range of 55.3 to 110.1% in the spiked levels of concentration of 40, 100 and 200 μg kg-1 and RSD ≤ 20%. Values of instrument LOD and LOQ were 1.5 and 5.0 μg L-1, respectively. Method LOQ was 100 μg kg-1 for most compounds. Thereby, It was concluded that the proposed method demonstrated to be adequate for the analysis of most pesticide residues studied in maize, since the parameters evaluated were in according to the limits required for chromatographic methods validation applied in residues analysis.
Devido à complexidade da sua matriz, métodos mais eficientes para a determinação de resíduos de agrotóxicos em milho têm sido estudados. O uso do método QuEChERS, juntamente com a técnica de precipitação a baixa temperatura tem apresentado vantagens para a redução de lipídios durante o preparo de amostra de matrizes com alto teor de gordura. Neste estudo, otimizou-se e validou-se um método multirresíduo para determinação de agrotóxicos em milho empregando QuEChERS e GC-MS/MS. O procedimento de extração, otimizado através de planejamento fatorial, constituiu na pesagem de 2,5 g da amostra, adição de 10 mL de água purificada, seguida de agitação em vórtex por 1 min e posterior adição de 10 mL de acetonitrila seguindo de agitação em agitador pendular por 1 h a 200 rpm. A partição utilizando sais foi realizada com 1 g de NaCl e 6 g de MgSO4 e agitação manual por 1 min, seguida de centrifugação a 3400 rpm por 8 min a 10 ⁰C. Uma alíquota de 4 mL do extrato foi retirada e transferida para um tubo de 15 mL para a etapa de limpeza do extrato a baixa temperatura por 12 h a aproximadamente -20 ⁰C. Após, efetuou-se a etapa final de limpeza do extrato com SPE dispersiva onde retirou-se 1 mL deste extrato e transferiu-se para um tubo contendo 150 mg de MgSO4, 50 mg de C18 e 50 mg de PSA, repetindo a agitação por 1 min e centrifugação a 3400 rpm por 8 min. O extrato final foi filtrado e analisado por GC-MS/MS. Os parâmetros analíticos avaliados neste trabalho foram a linearidade da curva analítica, limite de detecção (LOD), limite de quantificação (LOQ), precisão, exatidão e efeito matriz para os 12 compostos estudados. O método demonstrou-se eficiente, com resultados de recuperação na faixa de 55,3 a 110,1% nos níveis de fortificação 40, 100 e 200 μg kg-1 e com RSD ≤ 20%. Os valores de LOD e LOQ do instrumento foram de 1,5 e 5,0 μg L-1, respectivamente, e o valor de LOQ do método foi de 100 μg kg-1para a maioria dos compostos. Desta forma, conclui-se que o método otimizado mostrou-se adequado para análise da maioria dos resíduos de agrotóxicos estudados em milho, pois os parâmetros avaliados encontram-se dentro dos limites exigidos para validação de métodos cromatográficos aplicados a análise de resíduos.

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Beraldo, Daniele Alves de Souza. "Desenvolvimento e validação de método analítico para análise de bisfenol A e nonilfenol em águas superficiais da cidade de Americana, SP." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-24072012-142457/.

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Neste estudo determinou-se o nonilfenol - um composto xenobiótico utilizados na fabricação de antioxidantes, aditivos para óleos lubrificantes e produção de surfactantes etoxilados - e o bisfenol A - um composto químico utilizado na produção de diversos produtos, como, plásticos policarbonatos, resinas epóxi e retardantes de chama. Ambos exibem atividade estrogênica em concentrações abaixo de 1ng L-1 - em cinco pontos de coleta na cidade de Americana, SP. Devido à ampla utilização, esses compostos estão presentes em esgoto industrial em quantidades substanciais. A primeira etapa deste estudo foi a validação dos método analítico seguindo o Método 8270D da United States Environmental Protection Agency (USEPA) que descreve o procedimento de validação para os compostos semivoláteis analisados por cromatografia gasosa acoplada a espectrometria de massas (GC/MS). Os limites de detecção e de quantificação do método para a determinação do nonilfenol foram, respectivamente, 1 e 5 µg L-1. O coeficiente de determinação (R2) e a recuperação média para o nonilfenol foram, respectivamente, 0,99 e 99,04%. Os limites de detecção e de quantificação do método para o bisfenol A foram, respetivamente, 1 e 5 µg L-1. O coeficiente de determinação (R2) e a recuperação média para o bisfenol A foram, respectivamente, 0,99 e 91,55%. Na segunda etapa desta pesquisa analisaram-se amostras de água coletadas na cidade de Americana para a determinação do nonilfenol e do bisfenol A. Como método de extração dos compostos, usou-se a extração em fase sólida (SPE) e como técnica analítica a cromatografia gasosa acoplada a espectrometria de massas (GC/MS). Os resultados indicaram a presença desses compostos em alguns pontos de amostragem sendo que a concentração do nonilfenol a variou de 5,028 a 10,524 µg L-1 e para o bisfenol A a concentração variou de 5,645 a 295,255 µg L-1. Foram feitos também testes ecotoxicólogicos utilizando como organismo teste o microcrustáceo Daphnia similis, porém o nonilfenol e o bisfenol A, na concentração testada que variou de 0,05 a 500 µg L-1 não apresentaram toxicidade aguda.
In this study it was determined nonylphenol - a xenobiotic compound used in the manufacture of antioxidants, additives for lubricating oils and production of ethoxylated surfactant - and bisphenol A - a chemical compound used in production of various products, such as polycarbonate plastic, epoxy resins and flame retardants. Both exhibit estrogenic activity at concentrations lower than 1 ng L-1 - in five sampling points in the city of Americana, SP. Due to the widespread use of these compounds, they are present in substantial quantities in industrial sewage. The first step of this study was to validate the analytical method following the Method 8270D of the United States Environmental Protection Agency (USEPA) that describes the validation procedure for semi-volatile compounds analized by gas chromatography-mass spectrometry (GC/MS). The limits of detection and quantification for determining the nonylphenol were, respectively, 1 and 5 µg L-1. The coefficient ofdetermination (R2) and recovery for nonylphenol were respectively 0.99 and 99.04%. The limits of detection and quantification for the bisphenol A were, respectively, 1 and 5 µg L-1. The coefficient of determination (R2) and recovery for bisphenol A were respectively 0.99 and 91.55%. In the second step of this study were analized in water samples of Americana city for the determination of nonylphenol and bisphenol A. As a method of extraction of the compounds it was used solid-phase extraction (SPE) and as analytical technique GC/MS. The results indicated the presence of such compounds in some sampling points and the concentration of nonylphenol ranged from 5.028 to 10.524 µg L-1 and bisphenol A concentration ranged from 5.645 to 295.255 µg L-1. Ecotoxicological tests were also performed using as test organism microcrustaceans Daphnia similis, but nonylphenol and bisphenol A, tested at concentration ranging from 0,05 to 500 µg L-1 showed no acute toxicity.

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Skinner, Michael A. "Hapsite® gas chromatograph-mass spectrometer (GC/MS) variability assessment /." Download the thesis in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/Skinner2005.pdf.

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Asres, Daniel Derbie. "Characterization of carbohydrates using gas chromatography/mass spectrometry (GC/MS)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0001/MQ41677.pdf.

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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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RIZEL, PATRICIA. "QUALITATIVE STUDIES FOR DETERMINATION OF PYRENE METABOLITES USING GC/MS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4329@1.

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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Os Hidrocarbonetos Policíclicos Aromáticos (HPAs) são contaminantes carcinogênicos e mutagênicos, freqüentemente encontrados no ambiente. Muitos organismos são capazes de metabolizá-los rapidamente, tornando de fundamental importância o desenvolvimento de técnicas analíticas para a determinação de seus metabólitos. A determinação do 1- hidroxipireno é considerada com uma das primeiras etapas para a avaliação do risco ambiental por exposição dos HPAs. O pireno é um dos compostos predominantes desta classe de xenobióticos e o 1-hidroxipireno é o seu principal metabólito. Neste estudo é apresentado uma método para análise qualitativa do 1-hidroxipireno. Testes foram realizados afim de viabilizar a aplicação de uma metodologia para análises de rotina em amostras biológicas. O método escolhido envolve uma etapa de hidrólise ácida com subsequente extração líquido-líquido para obtenção do 1- hidroxipireno. A cromatografia de permeação em gel (CPG) foi empregada como um método de separação de lipídios, seguida de uma etapa de cromatografia líquida de coluna aberta. Uma vez que o 1-hidroxipireno é um composto de baixa volatilidade, foi incluída uma etapa de derivação com BSTFA e seguida de análise por CG/EM.
Polycyclic Aromatic Hydrocarbons are ubiquitous pollutants that usually present carinogenic and mutagenic effects. Several organisms are able to metabolize them quickly, and therefore becoming very important the development of analytical techniques for their metabolites determination. The chemical analyses of 1-hydroxipyrene is one of the first steps for evaluation of environmental assessment by PAH exposure. Pyrene is one of the principal compounds of this xenobiotic class and 1-hydroxipyrene is yours major metabolite. This study presents a method for qualitative analysis of 1-hydroxipirene. Tests were performed due to allow the use of a methodology for routine analysis in biological samples. The chosen method included acid hydrolysis followed of liquid-liquid extraction to obtain 1- hydroxipyrene. Gel permeation chromatography (GPC) was applied as a lipid separation method, and then liquid chromatography of opened column. As long as the 1- hydroxipyrene is a low volatile compound, it was included one step of derivatization with BSTFA followed by gas chromatography/mass spectrometer (GC/MS) analysis.

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Song, Xiling. "Analysis of Aroma Constituents in Cultivated Strawberries by GC/MS." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/42874.

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In aroma analysis, strawberries have always been the favored fruit because of their relatively high content of typical and pleasant aroma constituents. Esters, aldehydes, alcohols and sulfur compounds have been found to be the main aroma components in strawberry. In recent years, two volatile compounds, 2,5-dimethyl-4-methoxy-3(2H)-furanone (DMF) and 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DHF) were reported to contribute heavily to strawberry aroma. These two compounds have been found in all wild strawberries studied, but found only in few cultivated varieties. In this work, three kinds of cultivated strawberries were sampled and analyzed. The three strawberries all belong to the Camarosa variety. They came from different growing areas: Salinas (California), Orrville (Ohio), and Memphis (Tennessee). The volatile compounds of these three strawberries were separated by Gas Chromatography (GC), and identified by Mass Spectrometer Detector (MSD). Column and experimental conditions were optimized for this particular separation. Salinas, Orrville and Memphis strawberries have very similar aroma constituents, however, in slightly differing amounts. Several unique peaks were found in each strawberry, which may well account for the differences in the aroma qualities of the three. 2-Furaldehyde was found in both Memphis and Orrville strawberries, but not in Salinas. It is a key odor compound correlated with woody aroma and it has a low odor threshold value. These two properties make it contribute negatively to the pleasant aroma of Memphis and Orrville strawberries. A compound, 2-furanmethanol, was found only in Salinas strawberries. This compound has a faint burning aroma, however, its high odor threshold value offsets its potentially bad aroma. DMF was found in all three strawberries, but no DHF was detected in any of the three. We propose a possible explanation for the absence of DHF. Ethyl (methylthio) acetate, which is a sulfur-containing compound, was found in both Orrville and Salinas strawberries. This work is the first to report its presence in strawberries of any variety. An external standard method was employed to quantify seven main aroma components found in the strawberry extracts. Aroma values were introduced and then calculated together with sensory descriptions of these compounds. Salinas strawberry was found to have the best aroma quality of the three. These results indicate that the odors of strawberries of the same variety can be different when grown in different geographical areas.
Master of Science

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Souza, Patricia Regina de. "Avaliação de técnicas cromatográficas acopladas a espectrometria de massas para análise de morfolina em manga." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-18052016-143752/.

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A constante preocupação com o aumento do uso de agrotóxicos nas lavouras e os riscos gerados pelos resíduos destes compostos fazem com que os órgãos responsáveis pela fiscalização de alimentos no Brasil controlem a presença dessas substâncias nos produtos que chegam à mesa do consumidor. Atualmente, um dos grandes problemas na produção de alimentos é a utilização de substâncias proibidas em lavouras, muitas das quais não possuem estudos nem limites máximos de resíduos (LMR) estabelecidos, assim como a utilização de substâncias já registradas, mas em quantidades ou métodos de manejo incorretos. Ambos os casos podem resultar em sérios problemas à saúde humana. O objetivo deste estudo foi a avaliação da determinação de morfolina em amostras de manga utilizando técnicas como a Extração em Fase Sólida e a Cromatografia Gasosa acoplada à Espectrometria de Massas (SPE-GC-MS), assim como a Microextração em Sorvente Empacotado e Cromatografia Gasosa acoplada à Espectrometria de Massas (MEPS-GC-MS). Um segundo objetivo deste estudo consistiu em desenvolver, validar e avaliar uma metodologia analítica capaz de identificar quantitativamente a morfolina em amostras de manga por Cromatografia Líquida de Ultra Eficiência acoplada a Espectrometria de Massas em tandem (UHPLC-MS/MS). Para análise por GC-MS fez-se necessária a etapa de derivatização do analito, de forma que o mesmo aumentasse sua volatilidade e diminuísse a polaridade. A comparação entre as técnicas SPE e MEPS não foi possível devido ao efeito de matriz causado pela contaminação do liner e da coluna cromatográfica. Já a metodologia validada por UHPLC-MS/MS seguiu os critérios exigidos pelo Manual de Garantia da Qualidade Analítica, do Ministério da Agricultura Pecuária e Abastecimento (MAPA). O método foi aplicado em mangas de diferentes variedades obtidas no comércio local. Não foram encontrados resíduos de morfolina em nenhuma das amostras investigadas, de acordo com a metodologia proposta. Os resultados apresentados neste trabalho estabelecem metodologias eficientes, rápidas e de baixo custo na determinação de morfolina em amostras de manga.
The recurrent increasing of the use of pesticides on crops and the consequent risks due the exposure to chemical residues have urged the food regulation agencies to control the levels of these substances in products that reach consumer\'s table. A major problem nowadays for the production of food is the use of banned substances in crops and the extrapolation of the limit dosages of substances, which may result in serious problems to human health. Furthermore, many of these substances commonly used in crops still lack substantial information about the maximum residue levels (MRLs). The aim of this study was the evaluation of morpholine levels in mango samples using distinct techniques such as Solid Phase Extraction followed by Gas Chromatography coupled to Mass Spectrometry (SPE-GC-MS) and Microextraction by Packed Sorbent followed by Gas Chromatography Mass Spectrometry (MEPS-GC-MS). Another main goal of this work is the development, validation and evaluation of an analytical methodology to identify and quantitfy the presence of morpholine in mango samples, using Ultra-High Performance Liquid Chromatography coupled to tandem Mass Spectrometry (UHPLC-MS/MS). For the analysis of samples by GC-MS, it was required an initial step of derivatization of the analyte, in order to increase its volatility and reduce polarity. The comparison between SPE and MEPS techniques could not be performed due to matrix effects caused by contamination of the liner and the chromatographic column. On the other hand, the validated methodology for UHPLC-MS/MS presented herein followed all requirements proposed by the Analytical Quality Assurance Manual, accordingly to the Ministry of Agriculture, Livestock and Food Supply from Brazil. This method was applied in mango sample belonging to a wide variety of species found in the city of São Carlos, SP. Nevertheless, no significant levels of morpholine residues were found in any of the samples. In this work, we established a methodology efficient, fast and low cost for the determination of morpholine in mangos.

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Deuscher, Zoé. "Identifier les marqueurs clés de la qualité organoleptique des chocolats pour prédire leurs caractéristiques sensorielles." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCK012.

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

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Rocchi, Matteo. "Analisi e validazione di residui di antiparassitari su matrice acqua in GC/MS/MS." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16979/.

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Il presente lavoro è stato eseguito presso il laboratorio di analisi chimiche Tentamus Agriparadigma (Ravenna) che svolge analisi su diverse matrici (alimenti, acqua, cosmetici, terreni) ricercando in modo sicuro ed affidabile sostanze indesiderate quali pesticidi, residui di farmaci, metalli, etc. Sono stati presi in considerazione pesticidi clorurati e fosforati, oltre ai generici prodotti fitosanitari. I loro principi attivi sono sospette cause di patologie croniche; in particolare, esistono correlazioni tra l’esposizione a pesticidi e patologie come diabete, morbo di Parkinson, morbo di Alzheimer, e più recentemente la SLA. Quindi l’assenza di pesticidi nella matrice acqua viene assicurata mediante controlli eseguiti con metodi analitici sensibili, accurati e precisi e ovviamente validati. Validare un metodo significa confermare che ha capacità coerenti con ciò che richiede l'applicazione, nel nostro caso la capacità di estrarre e concentrare i residui di antiparassitari presenti in un campione di acqua reflua. I parametri da rispettare sono poi selettività e/o specificità, accuratezza (esattezza + precisione), limite di rivelabilità, recuperi, indicazione delle sorgenti di incertezza. Questi ed altri sono stati calcolati per ogni principio attivo saggiato in questa Tesi con metodologia GC/MS-MS. Sono stati approfonditi tutti i passaggi necessari per validare il suddetto metodo per 9 pesticidi, ottenendo risultati che statisticamente rientrano nei range previsti dalla normativa (APAT/IRSA). Sono stati valutati inoltre la tipologia della colonna, il flusso di gas, le condizioni di temperatura, e i parametri tecnico-operativi del gascromatografo, indispensabili per la ripetibilità di una analisi. I risultati confermano che il metodo di estrazione proposto ha una performance analitica soddisfacente allo scopo. Inoltre confermano con evidenze oggettive che il laboratorio analisi e la strumentazione in esso presenti sono idonei all’attività prevista.

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Lerch, Oliver. "Automatisierte Spurenanalyse endokrin disruptiver Substanzen mittels GC/MS-Methoden Festphasenextraktion, Derivatisierung, Tandem-MS-Detektion /." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968338291.

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Miranda, e. Silva Lígia Maria 1982. "Validação de método de análise de multiresíduos de defensivos agrícolas por GC-MS/MS e LC-MS/MS." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254815.

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Orientador: Marcelo Alexandre Prado
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O crescente aumento populacional em escala mundial, tornou necessário um grande esforço por parte da agricultura para aumentar, a cada ano, a produção de alimentos para atender as necessidades do mercado externo e interno do Brasil. Recursos técnicos e científicos passaram então, a serem aplicados em busca da melhoria na produção dos cultivos,principalmente mediante o uso de fertilizantes e praguicidas. Com isso, a sociedade se deparou com problemas de ordem de equilíbrio ambiental e saúde pública, pois devido à contínua diversificação dos fitoparasitas, surgem, a todo momento, reduções do período de tempo entre aplicações consecutivas, e mais importante talvez, usos de doses mais altas e emprego simultâneo de diferentes pesticidas, por parte dos agricultores, objetivando complementar ações específicas ou alcançar efeitos sinérgicos para maiores rendimentos na produção. Tal situação traz como conseqüência óbvia e direta, o aumento, inaceitável, dos riscos de contaminação do meio ambiente com resíduos químicos de defensívos da área agropecuarista prejudiciais à saúde, o que leva a inúmeros problemas relativos à segurança alimentar dos produtos consumidos, e à uma preocupação de âmbito nacional evidenciada pela criação do Programa de Análise de Resíduos de Agrotóxicos em alimentos (PARA) da ANVISA. O aumento na necessidade de detecção e quantificação destes compostos, acarretou o desenvolvimento de pesquisas no setor, a fim de atingir uma melhoria na eficiência,qualidade e rapidez de resposta nas análises. A possibilidade do estudo de não apenas um de cada vez, mas de até 300 compostos sendo extraídos, detectados e quantificados simultâneamente se tornou a saída mais viável, tanto qualitativa quanto economicamente, facilitando o monitoramento contínuo do fornecimento de produtos do setor alimentício pelos chamados métodos multiresíduos. O presentre trabalho teve como princípio a validação de um método multiresíduo para análise de 14 analitos usando uma técnica de alto poder de concentração e limpeza do extrato como o GPC (Gel Permeation Chromatography) e detecção e quantificação por GC-MS/MS e LC-MS/MS. Os pesticidas investigados englobam classes como: acaricidas, inseticidas, fungicidas, nematicidas e formicidas de aplicação foliar, em sementes ou em solo, sendo que o acefato, metamidofós, acetamiprido e o thiamethoxan foram extraídos de amostras de batata e feijão e analisados por LC-MS/MS e a azoxistrobina, bifentrina, carbofuran, chlorotalonil, clorpirifós, clorfenapir, etofenprox, famoxadone,metalaxil, procimidone e o tebuconazole em amostras de batata e tomate e analisados por GCMS/MS. Os limites de detecção (LD) encontrados variaram de 0,06 a 2,89µg/L, e os coeficientes de variação (CV), de 0,036 a 2,036%. As recuperações foram determinadas em cada tipo de amostras, e os valores encontrados estavam entre 93,34% e 109,67%. Nenhuma das matrizes utilizadas apresentaram resultados insatisfatórios e o método utilizado mostrouse robusto e de fácil aplicação para todos os analitos testados
Abstract: The growing population worldwide, has required a great effort on the part of agriculture to increase each year, the production of food to meet the needs of external and internal market of Brazil. Technical and scientific resources spent then, to be applied in pursuit of improved crop production, mainly through the use of fertilizers and pesticides.With this, the company encountered problems in the balance of environmental and public health, since due to the continuous diversification of plant parasites, arise at any moment,reductions in the time period between consecutive applications, and perhaps most important,uses more doses high and simultaneous use of different pesticides by farmers, aiming to complete specific actions or to achieve synergistic effects in producing higher yields. This situation brings obvious and direct consequence, the increase unacceptable risk of environmental contamination with chemical residues from pesticides in farms are harmful to health, which leads to numerous problems relating to food safety of the products consumed, and to a concern nationwide evidenced by the creation of the Program Analysis of Pesticide Residues in Food (TO) of ANVISA. The increase in the necessity for detection and quantification of these compounds, led the development of research in the sector in order to achieve an improvement in efficiency, quality and responsiveness in the analyzes. The possibility of studying not just one at a time, but up to 300 compounds being extracted,detected and quantified simultaneously output became more viable, both qualitatively and economically, facilitating continuous monitoring of the supply of products by the food industry called methods multiresidue. The principle presentre work was the validation of a multiresidue method for analysis of 14 analytes using a technique of high power concentration and cleanup of the extract as GPC (Gel Permeation Chromatography) and detection and quantification by GC-MS/MS and LC- MS / MS. The pesticides investigated include classes such as acaricides, insecticides, fungicides, insecticides and nematicides foliar, seed or soil,and acephate, methamidophos, and Acetamiprid thiamethoxan were extracted from samples of potatoes and beans and analyzed by LC-MS / MS and azoxystrobin, bifenthrin, carbofuran,chlorothalonil, chlorpyrifos, chlorfenapyr, etofenprox, famoxadone, metalaxyl, procymidone and tebuconazole in samples of potato and tomato and analyzed by GC-MS/MS. The limits of detection (LOD) ranged from 0.06 to 2.89 mg / L, and the coefficients of variation (CV), 0.036 to 2.036%. The recoveries were determined for each type of samples, and the values were between 93.34% and 109.67%. None of the arrays used had unsatisfactory results and method proved to be robust and easy to apply for all analytes tested
Mestrado
Ciência de Alimentos
Mestra em Ciência de Alimentos

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Mazollier, Aude. "Développement de méthodologies analytiques et statistiques pour le contrôle de la naturalité de matières premières pour la cosmétique et la parfumerie." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10004/document.

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Les huiles essentielles extraites de plantes aromatiques, médicinales et à parfum, sont utilisées depuis des millénaires pour leurs propriétés médicinales ou olfactives. Pour des raisons de rentabilité, les distributeurs sont contraints à réduire leur coût au maximum et à commercialiser des huiles essentielles au plus bas prix. Certains ont recours à la fraude et proposent, des essences de qualité inférieure sous la dénomination produits naturels de haute qualité. Il existe des normes (AFNOR, pharmacopées) qui doivent être respectées. Mais leur seule application est souvent limitée. Cette étude a donc permis une nette amélioration du contrôle de la naturalité des huiles essentielles de citrus, et lavande. La connaissance des compositions moléculaires des volatiles et des polymethoxyflavones (citron), l'étude énantiomérique de molécules cibles telles que l'alpha-pinène, le sabinène (citrus), le linalol et l’acétate de linalyle (bergamote et lavande), les analyses isotopiques du carbone 13, deutérium, des linalol, acétate de linalyle (bergamote et lavande), citral, acétate de géranyle (citron) ainsi que les analyses isotopiques du deutérium et azote 15 du N-méthyle anthranilate de méthyle (mandarine) sont les analyses permettant la mise en évidence de nombreux types de fraudes. Pour une méthodologie efficace, les analyses en composante principale et discriminante ont été indispensables. Elles ont permis l’identification d’échantillons fraudés via l’étude des volatiles. Les analyses chirales et isotopiques permettent l'identification d'échantillon plus “ finement ” adultérés ou de mieux comprendre les processus de fraude
Essential oils extract from aromatics, medicinal and perfume plants, are used since ancient times for their medicinal or olfactory properties. They are quite expensive, and owing to the actual growing demand for getting high quality materials at lowest prices, fraudulent essential oils are frequently found on the market. In order to fight this problem, norms exist (AFNOR, pharmacopeas) which have to be respected. However those techniques are often limited. This work allowed great improves in the quality control of citrus and lavender essential oils. The knowledge of the chemical composition of volatiles and polymethoxy-flavones (lemon), of the chirale ratios of alpha-pinene, le sabinene (citrus), linalool et linalyl acetate (bergamot et lavender), isotope ratio analyses of carbon 13, deuterium, of linalool, linalyl acetate (bergamot et lavender), citral, geranyl acetate (lemon) as wall as isotope ratio analyses of deuterium of nitrogen 15 du Nmethyl anthranilate de methyl (mandarin) permitted the detection of various type of frauds. In order to have an efficient methodology, principal component and discriminant analyses have been proved indispensables. It allowed the identification of fraudulent samples via volatiles molecules study. Chirale analysis and isotope ratio highlight frauds on more “discrete” adulterated samples or a better understanding of adulteration’s process

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Ehrenbergerová, Martina. "Stanovení reziduí vybraných pesticidních účinných látek ve víně metodou GC/MS." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216636.

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The grape is one of the oldest cultivated plants. It can be consumed as a fruit or it can be used as a raw material for making stews, juices or the cultivated drink – wine. Generations of wine-makers have been striving to improve both the cultivating conditions of vineyards and the quality of wine. Many harmful elements, such as herbivorous pests, diseases and storms are important factors that can have a negative impact on crop quality. To regulate the effects of these factors, an integrated protection system is used, incorporating agronomical measures, resistant varieties and a wide spectrum of pesticides. However, increasing the usage of pesticides brings certain dangers to both the production quality and the environment. This necessitates the monitoring of the negative effects, including the content of pesticide residues in the grapes. My thesis studies and experimentally assesses selected pesticide residues in certain wine samples.

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Urbina, Nelson D. "A Multivariate Model for Identification of Bacteria using Pyrolysis-GC/MS." Thesis, Uppsala University, Department of Mathematics, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-122468.

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Dickson, Sandra R. "Analytical studies of trace quantities of oxygenated sterols by GC-MS." Thesis, Glasgow Caledonian University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636798.

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Coronary heart disease caused by atherosclerosis is a major cause of premature deaths in developed countries . The etiology of atherosclerosis is unknown although elevated serum cholesterol levels are implicated as a major risk factor, and lipid lowering drugs have been successful in its treatment. Oxygenated sterols have also been implicated4 although due to their diversity, trace amounts compared to cholesterol and cholesterol autoxidation producing altifacts less is known of their risk. The work in this thesis optimised extraction and instrumental parameters that led to improved detection of oxysterols in serum. This was done through extraction and emichment of the oxysterols which removed the higher levels of 'swamping' cholesterol. Then by using novel derivatives and the softer negative ion chemical ionisation, this allowed the current to be concentrated in the molecular ion thus improving sensitivity. The determination of non-artifact cholesterol oxides which were prepared by adding perchloric acid to the serum, allowed for the assumption that subsequent cholesterol oxides formed in the work-up must be autoxidation artifacts. This allowed for a more accurate method of quantifying oxysterols in serum. The perchloric acid catalysed rearrangement of cholesterol oxides produced Cholestanetriol and Westphalin's diol which have been characterized with respect to standard compounds. However the elucidation of the structure of the third product, another ene diol was accomplished here using NMR and GC-MS studies since no standard reference compound was available. Trace oxysterols were identified and quantified in serum, through the optimization of parameters which improved detection and by the determination of autoxidation products.

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Eriksson, Emma. "GC-MS Screening and PCB Analysis of Sediment from Central Kattegat." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-45773.

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Five sediment samples were collected in Bua on the Swedish west coast, near two industries, a paper mill, and a nuclear power plant. The two industries use water in their processes and have long been associated with releases of different substances, such as PCBs, and other chlorinated compounds. The environmental impact by the two industries is believed to be significant. The aim of the project was to examine the sediments close to both the water intake and water output to determine if these industrial activities have in any way changed the composition of the sediments. The sediments were extracted by Soxhlet extraction, followed by a deactivated silica and an acidic silica clean-up and then analysed by using a gas chromatograph coupled to a mass spectrometer, (GC-MS) with electron ionization, EI+, mode used in full scan mode. Each mass spectra were analysed by comparing them to the NIST database from 1998. The results were inconclusive since the peaks were not properly resolved, causing a poor correlation to the NIST database. One batch was specifically analysed for polychlorinated biphenyls (PCB) by using an atmospheric pressure gas chromatograph (APGC) coupled to a mass spectrometer (MS). The PCB analysis provided accurate results, except for the Ringhals intake where the MS became saturated due to the high levels. The river Viskan also showed high levels of PCB. The congener pattern from PCBs found near Ringhals intake resembled an Aroclor pattern from Aroclor 1248. Since the Aroclor pattern is only seen in Ringhals intake, the source is most likely from the small harbour and not from either of the industries.

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Leppert, Jan [Verfasser]. "Schnelle Detektion luftgetragener chemischer Kampfstoffe mittels TD-GC-MS / Jan Leppert." Bonn : Universitäts- und Landesbibliothek Bonn, 2015. http://d-nb.info/1077290004/34.

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Ramos, Ana Isabel Martins Casal. "Determinação de estrogénios em águas de uma ETAR por GC-MS." Dissertação, Porto : [Edição do Autor], 2008. http://catalogo.up.pt/F?func=find-b&local_base=UPB01&find_code=SYS&request=000108340.

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Ramos, Ana Isabel Martins Casal. "Determinação de estrogénios em águas de uma ETAR por GC-MS." Master's thesis, Porto : [Edição do Autor], 2008. http://hdl.handle.net/10216/63996.

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Oliveira, Renata Cabrera de 1984. "Avaliação do potencial do pólen apícola como bioindicador de contaminação ambiental por agrotóxicos." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249441.

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Orientadores: Susanne Rath, Sonia Claudia do Nascimento de Queiroz
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: O uso frequente e indiscriminado de agrotóxicos na agricultura tem acarretado a presença de resíduos nos alimentos e contaminação ambiental, principalmente em países com grande potencial agrícola, como o Brasil. Para avaliar a presença de resíduos de agrotóxicos no ambiente, as abelhas e os produtos apícolas têm sido apontados como potenciais bioindicadores, podendo ser utilizados para monitorar grandes áreas devido às longas distâncias percorridas. Assim sendo, o potencial do uso do pólen apícola como bioindicador da contaminação ambiental por agrotóxicos foi avaliado neste trabalho. Para isso, foi necessário desenvolver e validar um método analítico para determinação de multirresíduos em pólen apícola, utilizando cromatografia a gás acoplada à espectrometria de massas sequencial (GC-MS/MS). Para definição das condições ótimas de extração, dois processos foram avaliados: o QuEChERS, e o de partição com acetonitrila. O QuEChERS mostrou ser mais eficiente (melhor seletividade e eficiência de extração) e foi validado para a determinação de 27 agrotóxicos. Estudos de sorção mostraram que os agrotóxicos são fortemente sorvidos no pólen. Nas amostras provenientes do apiário experimental na Embrapa em Jaguariúna/SP não foram encontrados níveis quantificáveis dos agrotóxicos pesquisados, enquanto a presença de resíduos de agrotóxicos nas amostras fornecidas por apicultores de Ribeirão Preto/SP foi confirmada e quantificada. Os métodos desenvolvidos e validados mostraram ser eficientes e podem ser utilizados no monitoramento ambiental quanto à presença de resíduos de agrotóxicos. Os resultados confirmam o potencial do pólen apícola como bioindicador de contaminação ambiental por agrotóxicos
Abstract: The extensive use of pesticides in agriculture crop has led to the presence of residues in food and environmental contamination, especially in countries with great agricultural potential, such as Brazil. To assess the presence of pesticide residues in the environment, honeybees and bee products have been mentioned as potential bioindicators, which can be used to monitor large areas due to long distances travelled. Therefore, the potential use of bee pollen as a bioindicator of environmental pesticides contamination has been reported in this work. For this it was necessary to develop and validate an analytical method for the determination of multiresidues in pollen, using gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). For the definition of optimum extraction conditions, two procedures were evaluated: QuEChERS, and partition with acetonitrile. The QuEChERS proved to be more efficient (improved selectivity and extraction efficiency), and was validated for the determination of 27 pesticides. Sorption studies showed that pesticides are strongly sorbed in pollen. Unquantifiable levels of pesticides surveyed were found in the samples from experimental apiary at Embrapa in Jaguariúna/SP, while the presence of pesticide residues in samples provided by apiarists from Ribeirão Preto/SP was confirmed and quantified. The validated analytical methods proved to be efficient and can be used in environmental monitoring for the presence of pesticide residues. The results confirm the potential of bee pollen as a bioindicator of environmental pesticides contamination
Doutorado
Quimica Analitica
Doutora em Ciências

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Bichon, Emmanuelle. "Challenge de l’analyse de dangers chimiques à l’état d’ultra-traces en matrices biologiques complexes." Thesis, Nantes, Ecole nationale vétérinaire, 2016. http://www.theses.fr/2016ONIR089F/document.

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L’étude du lien entre l’exposition de l’Homme aux substances chimiques, notamment via son alimentation,et sa santé est un sujet de préoccupation majeure dans notre société qui présente des challenges multiples.Nous nous sommes attelés à l’un d’entre eux par la production de données analytiques fiables relatives à la contamination des denrées alimentaires et des fluides biologiques humains. Le développement de méthodes analytiques reposant sur des technologies en rupture, à même de s’adresser aux paris de la mesure de composés chimiques émergents (e.g. les retardateurs de flamme bromés) ou historiques mais sous le prisme de la sensibilité et du haut débit (e.g. les stéroïdes, les pesticides organochlorés, les dioxines et les polychlorobiphényles) a été au cœur de ce travail. Le couplage GC/APCI/MS sur système triple quadripolaire s’est imposé au cours de nos évaluations. L’association de la chromatographie en phase gazeuse et de l’ionisation chimique à pression atmosphérique a apporté un gain en sélectivité remarquable comparée aux approches traditionnellement retenues dans le domaine et a autorisé l’exploration des ultra-traces dans des matrices biologiques complexes. Cette géométrie nous a permis d’innover en pratiquant des séparations rapides sur colonne capillaire ultra-courte de 2,5 m. La vitesse de balayage et l’excellente sensibilité de l’analyseur de masse nous ont en outre donné accès à une analyse quantitative fiable et multi-paramètres. Ce travail ouvre d’excellentes perspectives vis-à-vis de la production de données d’exposition externe et interne élargies en réponse aux défis à venir entourant la caractérisation de l’exposome Humain
The study of the link between Human exposure tochemical substances (notably via his food the intake) and Health, is a major concern in our society and poses many challenges. We endeavoured to address one of them by producing reliable analytical data on foodstuffs and human biological fluids contamination. The development of analytical methods based on breakthrough technologies, capable of challenging theemerging (e.g. brominated flame retardants) or historical compounds measurement but through the prism of sensitivity and high throughput (e.g. steroids,organochlorine pesticides, dioxins andpolychlorobiphenyls), was at the heart of our work.Using a GC/APCI/MS with a triple quadripole systememerged as a favorable choice as our evaluations progressed. The association of gas chromatography and atmospheric pressure chemical ionisation brought in a remarkable gain in terms of selectivity, compared to the approaches traditionally selected in this field, andauthorized ultra-trace exploration in complex biologicalmatrices. This geometry allowed us to innovate by performing fast separations on an ultra-short 2.5 mcolumn. Besides, the mass analyser scan speed and high sensitivity gave us access to a reliable and multiparameters quantitative analysis. This work opens up excellent perspectives for the production of expanded external and internal exposure data to meet the future challenges surrounding Human exposome characterisation

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Donato, Filipe Fagan. "Resíduos de agrotóxicos em água potável usando SPE e determinação rápida por LC-MS/MS e GC-MS/MS." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/10528.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
The use of pesticides always has been associated with the effective control of pests or invasive weeds to ensure an increase in the food production. However, the indiscriminate use of these substances has caused the degradation of water resources. In Brazil, the Ministry of Health through Ordinance 2914 defines several parameters of potability, among them, the maximum limits allowed for same pesticides. In this work it was developed and validated a method for the determination of residues of 70 pesticides in drinking water using (SPE) for sample preparation and determination by Gas and Liquid Chromatography coupled to tandem mass spectrometry, triple quadrupole analyzer (GC-(TQ)MS/MS and LC- (TQ)MS/MS). It was evaluated different sample volume, sorbents and solvent of elution. The best results were obtained using 100 mL sample acidified at pH 2.5, Oasis® SPE cartridge HLB 60 mg/3 mL and dichloromethane/methanol as eluent. Analytical curves were linear between 10 and 250 Sg L-1, with r2 values greater than 0.99 for all compounds. The values of method LOQ were 0.02 Sg L-1 for aldrin, dieldrin and chlordane and 0.5 Sg L-1 for the other compounds. To evaluate accuracy the blank samples ware fortified at 0.5, 1.5 and 4.0 Sg L- 1 and an extra level at 0.02 Sg L-1 for aldrin, dieldrin and chlordane. The method showed good precision, with RSD values below to 20% and good accuracy, with recoveries between 70 and 120%. Only the compounds methamidophos, aldicarb, benfuracarb, terbufos, benomyl and thiophanate methyl were not recovered adequately. The matrix effect was evaluated, showing upper 10% for the most compounds. In order to compensate this effect, analytical curves were obtained with standarts prepared in blank extracts of the matrix. The validated method was applied to 12 samples of drinking water of different characteristics (river, shed, well and treated water), and just one of the river samples presented residues of lambda-cyhalothrin. The results indicate that the proposed method is suitable for analysis of pesticides residues in drinking water, since all the validation parameters met the suggested limits and parameters for validation of chromatographic methods.
O uso de agrotóxicos sempre esteve associado à efetividade no controle de pragas ou plantas invasoras para aumentar a produção de alimentos. No entanto, o uso indiscriminado dessas substâncias vem causando a degradação dos recursos hídricos. No Brasil, o Ministério da Saúde através da Portaria 2914 define diversos parâmetros de potabilidade, entre eles, os limites máximos permitidos para alguns agrotóxicos. No presente trabalho foi desenvolvido e validado um método para a determinação de resíduos de 70 agrotóxicos em água potável, utilizando Extração em Fase Sólida (SPE) para o preparo de amostra e determinação por Cromatografia Gasosa e Líquida, acopladas à Espectrometria de Massas sequencial, com analisador triplo quadrupolo (GC-(TQ)MS/MS e LC- (TQ)MS/MS). Foram avaliados diferentes volumes de amostra, sorventes e solventes de eluição. Os melhores resultados foram obtidos com 100 mL de amostra acidificada em pH 2,5, cartucho SPE Oasis® HLB 60 mg/3 mL e diclorometano/metanol como eluente. As curvas analíticas apresentaram linearidade entre 10 e 250 Sg L-1, com valores de r2 maiores que 0,99 para todos os compostos. Os valores de LOQ do método foram 0,02 Sg L-1 para aldrin, dieldrin e clordano e de 0,5 Sg L-1 para os demais compostos. Para avaliação da exatidão as amostras branco foram fortificadas em 0,5, 1,5 e 4,0 Sg L-1 e um nível extra em 0,02 Sg L-1 para os compostos aldrin, dieldrin e clordano. O método apresentou boa precisão, com valores de RSD inferiores a 20% e boa exatidão, com recuperações entre 70 e 120%. Apenas os compostos metamidofós, aldicarbe, benfuracarbe, terbufós, benomil e tiofanato metílico não foram recuperados de forma adequada. O efeito matriz foi avaliado, mostrando-se superior a 10% para a maioria dos compostos. A fim de compensar este efeito, utilizou-se curvas analíticas preparadas no extrato branco da matriz. O método validado foi aplicado em 12 amostras de água potável de diferentes características (rio, vertente, poço e água tratada), sendo que apenas uma das amostras de água de rio apresentou resíduos de lambda-cialotrina. Os resultados indicam que o método proposto é adequado à análise de resíduos de agrotóxicos em água potável, visto que todos os parâmetros de validação atenderam os limites e parâmetros sugeridos para validação de métodos cromatográficos.

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Coat, Rémy. "Caractérisation des voies métaboliques et des marqueurs précoces de l'altération microbiologique des ovoproduits au cours de leurs procédés de fabrication." Thesis, Nantes, 2018. http://www.theses.fr/2018NANT4038/document.

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L’ovoproduit est une matrice biologique complexe, constituée de protéines, lipoprotéines, lipides et de nombreux micronutriments (vitamines, minéraux, etc.). Cependant, une fois cassé et homogénéisé l'ovoproduit entier liquide perd une bonne part de ses propriétés de conservation, devenant ainsi pour certaines bactéries un excellent milieu de croissance. Ce développement bactérien non maîtrisé provoque en plus des risques sanitaires, des altérations biochimiques modifiant fortement les qualités organoleptiques de l’ovoproduit. On se propose dans cette thèse d’étudier les mécanismes biochimiques impliqués par des approches de métabolomique combinées (profilage métabolique par GC-MS et prise d’empreinte métabolique par GC-MS et RMN). Cette approche permettra de décrire et de comprendre de façon intégrée certains mécanismes jusqu’alors peu ou pas caractérisés et d'identifier in fine des marqueurs précoces de ces altérations microbiologiques
Egg products are complexes biological matrix constituted of proteins, lipoproteins, lipids and many micronutrient (vitamins, mineral, etc…). However, once broken and mixed, the liquid egg product looses a great deal of its keeping properties, thus becoming an excellent growth media for many bacteria. This uncontrolled bacterial development induces, beside the involved health risks, biochemical alterations which modify the product’s organoleptic qualities. This manuscript aims to study the involved biochemical mechanisms using combined metabolomics approaches (Metabolic profiling by GC-MS and metabolic fingerprinting by GC-MS and NMR). This approach will allow the description and understanding of certain mechanisms which characterization was previously absent or limited. It will also allow the identification of early prediction biomarkers of these biological alterations

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Santos, Anai Loreiro dos. "Caracterização química por GC/qMS e GC×GC/TOF-MS e avaliação da atividade antioxidante dos óleos essenciais de campomanesia guazumifolia (Cambess.) O. Berg. e Piper regnellii (Miq.) C. DC." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/180653.

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O presente trabalho alia a capacidade analítica da GC×GC/TOF-MS ao uso dos índices de retenção e ferramentas adequadas de software para o estudo de óleos essenciais de Campomanesia guazumifolia (Cambess.) O. Berg. (guabiroba) e Piper regnellii (Miq.) C. DC. (pariparoba). O óleo essencial de folhas de C. guazumifolia apresentou 69 compostos tentativamente identificados, sendo o biciclogermacreno (48%), o composto majoritário. As folhas, caules e flores de P. regnellii geraram óleos essenciais com 172, 126 e 115 compostos tentativamente identificados, respectivamente. Os compostos majoritários em cada óleo essencial foram aproximadamente os mesmos, com exceção do dilapiol, que só esteve entre os majoritários no óleo essencial dos caules: o mirceno, anetol E e biciclogermacreno (22%, 19% e 5%, respectivamente, nas folhas), anetol E, dilapiol e mirceno (20%, 19% e 16%, respectivamente nos caules) e anetol E, mirceno e biciclogermacreno (24%, 18% e 9%, respectivamente nas flores). Também foi detectada atividade antioxidante moderada para os óleos essenciais das folhas, caules e flores de P. regnellii.
This work combines the analytical capability of GC × GC / TOF-MS, the use of retention indices and adequate software tools for the study of essential oils of Campomanesia guazumifolia (Cambess.) O. Berg. (guabiroba) and Piper regnellii (Miq.) C. DC. (pariparoba). The essential oil from the leaves of C. guazumifolia showed 69 compounds tentatively identified, being bicyclogermacrene (48%), the major compound. The leaves, stems and flowers of P. regnellii generated essential oils with 172, 126 and 115 compounds tentatively identified, respectively. The major compounds in each essential oil were approximately the same, except dilapiol, who was among the majority only in the essential oil of the stems: myrcene, bicyclogermacrene and anethole E (22%, 19% and 5%, respectively, in leaves), anethole E, dilapiol and myrcene (20%, 19% and 16% respectively in stems) and anethole E, myrcene and bicyclogermacrene (24%, 18% and 9%, respectively in flowers). It was also detected a moderate antioxidant activity in the essential oils of leaves, stems and flowers of P. regnellii.

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Witrick, Katherine Amy Thompson. "Characterization of aroma and flavor compounds present in lambic (gueuze) beer." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/19203.

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Lambic beer is one of the oldest beer styles still being brewed in the western world today and the only beer that is still brewed through spontaneous fermentation. Lambic beers are only produced within a 500 km radius of Brussels because of the natural microflora found within the air in that region. Little is known about the chemical composition of lambic beers. The objective of this research were (1) to compare SPME and SAFE for the isolation of flavor and aroma compounds, (2) determine the volatile composition and acids of commercially available lambic gueuze using SPME/GC-MS and HPLC, and (3) determine the major aroma compounds of aging lambic beer using GC-O. Comparing the two extraction methods, both SPME and SAFE were able to identify a similar number of chemical compounds, however SAFE identified a greater number of acid compounds. A total of 50 compounds were identified within nine commercial brands of lambic beer. HPLC was used in the identification and quantification of acetic and lactic acids. The concentration of acetic acid in the commercial products ranged from 723 mg/L â " 1624 mg/L and lactic acid ranged from 995 â " 2557 mg/L. GC-O was used in the analysis of aged (3-28 months) lambic beer samples. As the samples increased in age, the number of aroma compounds detected by the panelists also increased. Panelists were detected nine aroma compounds in the 3 month old sample, while 17 compounds were detected in the 28 month old sample. The research conduct increased the number of volatile and semi-volatile compounds identified in lambic beer from 27 to 50.
Ph. D.

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Mayer, Karine Kochhann Rhoden. "Desenvolvimento e validação de método multirresíduo, empregando GC-ECD E GC-MS, para a investigação de pesticidas em morango, maçã e uva." Universidade Federal de Santa Maria, 2005. http://repositorio.ufsm.br/handle/1/10420.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Pesticides use is still the main strategy used in the field for the combat and the prevention of agricultural plagues, guaranteeing enough food and of quality for the population. In the culture of fruits, especially in strawberries, apples and grapes, the consequent contamination by pesticide residues has the been objective of constant concern in the ambit of the public health. Due to the toxicity associated with these substances quality of the produced victuals is necessary in order to prevent possible risks to the consumer. In the present study, a multiresidue method was developed and validated for the quantification of the pesticides chlorothalonil, chlorpyrifos, captan, procymidone, kresoxim methyl, iprodione, fenpropathrin, deltamethrin and azoxystrobine using Gas Chromatography with Electron Capture Detection (GCECD) in different matrices (strawberry, apple and grape). Gas Chromatography coupled with Mass Spectrometry (GC-MS) was used for the investigation of the pesticides present in the samples. Some extraction conditions were appraised, such as type and volume of solvents, amount of sample and purification of the extract. The extraction with 1:1 (v/v) mixture of ethyl acetate/n-hexane, in ultraturrax, followed by purification in florisil® columns and reduction of the extract volume by evaporation of the solvent presented the best results. The optimized conditions for the GC-ECD system were: capillary column DB-5; programming of the oven temperature: 80 °C - 2 min, 180 °C (10 °C min-¹)- 1 min, 255 °C (8 °C min-¹); 315 °C (15 °C min-¹) 4.25 min, pressure of the carrier gas (He) 21 psi; injection volume 1 μL; injetor temperature 270 °C and of the detector to 330 °C. For the analysis by GC-MS the used conditions were: capillary column VF - 5MS, Factor Four/MS (Varian) with 5 m of EZ-Guard®; programming of the column temperature: 80 °C (25 °C min-¹), 180 °C (5 °C min- ¹), 280 °C - 10 min, pressure of the carrier gas 10 psi; injection volume 1 μL, in the splitless mode; temperature of the manifold of 80 °C and of the interface of 230 °C, energy of 600 eV applied to the ion multiplier and ion-trap temperature of 200 °C. In the validation of the method the following parameters were verified: detection limit (LOD), quantification limit (LOQ), linearity, precision (repeatability and intermediary precision) and recovery. LODs and LOQs of the instrument varied from 2.5 to 18.7 μg L-¹ and from 5.0 to 25.0 μg L-¹, except for the deltamethrin (0.2 and 0.8 μg L-¹), respectively. For the analyzed samples obtained LOQs values from 0.6 to 15.6 mg kg-1 were obtained for the pesticides in study. The analytical solutions were prepared in "blank extract" of the fruits to compensate for the observed matrix effect, being obtained analytical curves with r2 ≥0.9925. The precision assays supplied acceptable results, with RDS values between 0.3 and 14.8%. Recoveries from 85.4 to 111.3% were obtained for the studied matrices, except for captan in grape (70.1%). The results obtained in the validation allowed us to conclude that the method is adaptable for the determination of these compounds in strawberries, apples and grapes, being that the method was applied in the analysis of 21 samples obtained in the trade. Pesticides presences were verified in 72.7% in the strawberry samples, 80% of the apple and grape samples, where chlorpyrifos, chlorothalonil, captan, iprodion, deltamethrin and fenpropathrin were found.
O uso de pesticidas é ainda a principal estratégia no campo para o combate e a prevenção de pragas agrícolas, garantindo alimento suficiente e de qualidade para a população. Na fruticultura, em especial nas culturas de morango, maçã e uva, a contaminação por resíduos de pesticidas têm sido alvo de constante preocupação no âmbito da saúde pública e da sociedade. Devido à toxicidade associada a estas substâncias o monitoramento da qualidade dos alimentos produzidos é necessário a fim de prevenir possíveis riscos ao consumidor. No presente trabalho foi desenvolvido e validado um método multirresíduo para a quantificação dos pesticidas clorotalonil, clorpirifós, captana, procimidona, cresoxim metílico, iprodiona, fenpropatrina, deltametrina e azoxistrobina empregando Cromatografia Gasosa com Detecção por Captura de Elétrons (GC-ECD) em diferentes matrizes (morango, maçã e uva). A Cromatografia Gasosa acoplada a Espectrometria de Massas (GC-MS) foi empregada para a investigação da presença de pesticidas nas amostras. Algumas condições de extração foram avaliadas, tais como tipo e volume de solventes, quantidade de amostra e purificação do extrato. A extração com mistura 1:1 (v/v) de acetato de etila/n-hexano, em ultra-turrax, seguida de purificação em colunas de florisil® e redução do volume do extrato por evaporação do solvente foi a que apresentou melhores resultados. As condições otimizadas para o sistema GC-ECD foram: coluna capilar DB-5; programação da temperatura do forno: 80 ºC 2 min, 180 ºC (10ºC min- ¹) - 1 min, 255 ºC (8 ºC min-¹); 315 oC (15 ºC min-¹) 4,25 min, pressão do gás de arraste (He) 21 psi; volume de injeção 1 μL; temperatura do injetor 270 °C e do detector a 330 ºC. Para a análise por GC-MS usaram-se as condições: coluna capilar VF- 5MS, Factor Four/MS (Varian) com 5 m de EZ-Guard®; programação da temperatura da coluna de: 80 ºC (25 °C min-¹), 180 ºC (5 ºC min-¹), 280 ºC 10 min, pressão do gás de arraste 10 psi; volume de injeção 1 μL, no modo splitless; temperatura do manifold de 80 °C e da interface de 230 °C, energia de 600 eV aplicada à multiplicadora de íons e temperatura do iontrap a 200 ºC. Na validação do método foram avaliados os seguintes parâmetros: limite de detecção (LOD), limite de quantificação (LOQ), linearidade, precisão (repetitividade e precisão intermediária) e recuperação. Os LODs e LOQs do instrumento variaram de 2,5 a 18,7 μg L-¹ e de 5,0 a 25,0 μg L-¹, exceto para a deltametrina (0,2 e 0,8 μg L-¹), respectivamente. Para as amostras analisadas obtiveram-se valores de LOQs de 0,6 a 15,6 μg kg-¹ para os pesticidas em estudo. As soluções analíticas foram preparadas em extrato branco das frutas para compensar o efeito matriz observado, obtendo-se curvas analíticas com r² ≥ 0,9925. Os ensaios de precisão forneceram resultados aceitáveis, com valores de RDS entre 0,3 e 14,8%. Recuperações de 85,4 a 111,3% foram obtidas para as matrizes estudadas, exceto para a captana (70,1%) em uva. Os resultados obtidos na validação permitiram concluir que o método é adequado para determinação destes compostos em morango, maçã e uva, sendo o método aplicado na análise de 21 amostras obtidas no comércio. Foram constatadas presenças de pesticidas em 72,7% das amostras de morango, 80% das amostras de maçã e de uva, onde foram encontrados clorpirifós, clorotalonil, captana, iprodiona, deltametrina e fenpropatrina.

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Mesquita, Katia Aparecida. "Estudo dos poluentes orgânicos persistentes (POPs) no sedimento da Represa Billings - SP via cromatografia a gás acoplada à espectrometria de massas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-23102017-115049/.

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O estudo objetivou desenvolver uma novo método de extração para analisar os poluentes orgânicos persistentes (POPs), no sedimento da Represa Billings em São Paulo, via cromatografia a gás com espectrometria de massas (GC/MS). O Tratado de Estocolmo realizado na Suécia em 1972, patrocinado pela ONU, possuindo 113 países participantes, inclundo o Brasil objetivou a eliminação de menos doze POPs, colaborando com a questão ambiental. Os POPs são compostos que persistem no meio ambiente e são altamente estáveis, podendo ultrapassar a barreira placentária. Neste trabalho foram abordados o Aldrin, Endrin, Dieldrin, DDT. DDE, DDD e Heptacloro. Para garantir a confiabilidade dos resultados analíticos, foram realizados ensaios de validação do método, baseados nas diretrizes do INMETRO. O método de extração dos analitos foi o Quechers, obtendo resultados de recuperação entre 40 e 120% para todos os POPs analisados neste trabalho, valores aceitáveis para matrizes complexas como o sedimento. Os limites de detecção e quantificação fora, 0,3 e 0,5 μg/kg respectivamente. As amostras analisadas não apresentaram contaminação significativa por POPs perante a Legislação Brasileira vigente.
The objective of this study was to develop a new extraction method to analyze persistent organic pollutants (POPs) in the Billings Reservoir sediment in São Paulo, using gas chromatography with mass spectrometry (GC / MS). The 1972 Stockholm Treaty, sponsored by the UN, with 113 participating countries, including Brazil, aimed at eliminating at least twelve POPs, collaborating with the environmental issue. POPs are compounds that persist in the environment and are highly stable and can overcome the placental barrier. In this work were approached: Aldrin, Endrin, Dieldrin, DDT. DDE, DDD and Heptachlor. In order to guarantee the reliability of the analytical results, validation tests of the method were carried out, based on INMETRO guidelines. The method of extraction of the analytes was Quechers, obtaining results of recovery between 40 and 120% for all POPs analyzed in this work, acceptable values for complex matrices such as sediment. The limits of detection and quantification were, respectively, 0.3 and 0.5 μg / kg. The analyzed samples did not present significant contamination by POPs before the current Brazilian Legislation.

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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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Dunstan, R. H. "A GC-MS approach to carbon and nitrogen metabolism in Paracoccus denitrificans." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370248.

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Harms, Ralph Nicholas Sebastian [Verfasser]. "Quantitative polymer-additive analysis using Pyrolysis-GC/MS / Ralph Nicholas Sebastian Harms." Mainz : Universitätsbibliothek Mainz, 2018. http://d-nb.info/1161813985/34.

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45

Demir, Cevdet. "Detection of metabolites by GC-MS and analysis of mixtures by chemometric." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388014.

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Riedel, Casper. "Ethnopharmacological evaluation through literature review and GC-MS analysis of Baccharis magellanica." [Copenhagen] : University of Copenhagen, Faculty of Life Sciences, Department of Plant Biology, 2007. http://www.forskningsbase.life.ku.dk/retrieve/6144494?format=application/pdf.

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Dallegrave, Alexsandro. "Determinação de hormônios estrógenos e progestágenos em amostras ambientais por GC-MS." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/66440.

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Em razão do constante aumento populacional, o nível de poluição no planeta tem crescido principalmente nos meios aquáticos. Parte destes contaminantes apresentam regulamentação, porém uma fração destes, chamados de “emergentes”, são constantemente lançados no ambiente sem nenhum controle além de não apresentarem regulamentação. Os hormônios sexuais fazem parte destes contaminantes emergentes e oferecem grande risco as diferentes formas de vida devido ao alto potencial em causar disrupção endócrina. Neste trabalho desenvolveu-se a metodologia analítica com o intuito de determinar e quantificar cinco hormônios sexuais, amplamente consumidos na reposição hormonal e contraceptivos. A determinação dos hormônios sexuais estrona (E1), β-estradiol (E2), estriol (E3), 17α-etinilestradiol (EE2) e progesterona foi realizada através da cromatografia a gás acoplada a espectrometria de massas com derivatização prévia. A derivatização dos estrógenos E1, E2, E3 e EE2 foi realizada com MSTFA-Imidazol, já a progesterona foi determinada na forma não derivatizada. Parâmetros como tempo e temperatura de derivatização, tipos de derivatizante e energia do impacto eletrônico no espectrômetro de massas, foram devidamente otimizados. A pré-concentração foi realizada por extração em fase sólida (SPE), utilizando cartuchos Oasis HLB e a validação do método foi conduzida pela avaliação dos parâmetros: linearidade, sensibilidade, seletividade, precisão, precisão intermediária, exatidão, limite de detecção e de quantificação. A amostragem de águas superficiais e efluente urbano foi realizada nos meses de agosto, setembro e outubro de 2012, nos Rios Gravataí e dos Sinos, no Arroio Dilúvio, e na estação piloto de tratamento de efluente urbano, pertencente ao Instituto de Pesquisas Hidráulicas (IPH/UFRGS). Os hormônios E1, E2 e E3 foram encontrados nas amostras em concentrações de 6,2 a 541,4 ng L-1, 29 a 46,2 ng L-1 e 37,5 a 716,8 ng L-1 respectivamente. No estudo preliminar de degradação do EE2 , foram avaliadas a fotólise direta em água purificada e indireta com utilização de íons nitrato nas concentrações 20 e 100 mg L-1, sendo as constantes da taxa de transformação 0,0128 min-1, 0,0175 min-1 e 0,0336 min-1 respectivamente. A fotodegradação também foi avaliada em diferentes matrizes: água purificada, efluente urbano e água da torneira, sendo as constantes da taxa de transformação 0,0451 min-1, 0,0227 min-1 e 0,0864 min-1 respectivamente. Os sistemas investigados seguem uma cinética de pseudo-primeira ordem. Este estudo serve de base para futuramente determinar possíveis produtos de transformação.
Due to the constant increase in population, the level of pollution on the planet has grown mainly in aquatic environments. Some of these contaminants present regulation but a fraction of these, called "emerging", besides being continuously released into the environment without any control, have no regulation. Sex hormones are part of these emerging contaminants and offer great risk the different ways of life due to their potential to cause endocrine disruption. In this work the development of analytical methodology was enhanced in order to determine and quantify five sex hormones, widely consumed in hormone replacement and contraceptives. The determination of compounds estrone (E1), β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2) and progesterone was performed by gas chromatography coupled with mass spectrometry with previous derivatization. Derivatization of estrogens E1, E2, E3 and EE2 was performed using MSTFA-Imidazole, while the progesterone was determined in the non-derivatized form. Parameters as temperature and time of derivatization, and types of derivatives , energy of electron impact on mass spectrometer, were properly optimized. The preconcentration was performed by solid phase extraction (SPE) using Oasis HLB cartridges. The method validation was carried out by evaluating the parameters: linearity, sensitivity, selectivity, precision, intermediate precision, accuracy, limit of detection and quantification. The sampling was performed in the months of August, September and October of 2012 in Gravataí and Sinos rivers, Dilúvio Stream and urban sewage in wastewater treatment pilot plant, which belongs to the Institute of Hydraulic Research (IPH / UFRGS ). The hormones E1, E2 and E3 were found in samples at concentrations from 6.2 to 541.4 ng L-1, from 29 to 46.2 ng L-1 and from 37.5 to 716.8 ng L-1 respectively. In the preliminary study of degradation of EE2, in purified water photolysis direct and indirect use of concentrations ions nitrate 20 and 100 mg L-1 were assessed, with transformation rate constants 0.0128 min-1, 0.0175 min-1 and 0.0336 min-1 respectively. The photodegradation in different matrices: purified water, urban wastewater and tap water also were assessed, with transformation rate constants 0.0451 min-1, 0.0227 min-1 and 0.0864 min-1 respectively. The systems investigated kinetics follow pseudo-first order. This study provides a basis to determine in the future possible transformation products.

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Wang, Ting. "Monitoring a natural autoxidation process of methyl linoleate by using GC-MS." Scholarly Commons, 2003. https://scholarlycommons.pacific.edu/uop_etds/586.

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The methyl ester of an unsaturated fatty acid, methyllinoleate was reacted with oxygen in a pressurized system at a controlled temperature. A natural autoxidation of methyl linoleate was observed without the addition of an initiating reagent. This autoxidation process could be used to mimic the course of lipid peroxidation, which is the major cause ofradical damage to living cells. The technology of GC-MS was employed to monitor the autoxidation of methyllinoleate. Eight of the autoxidation products separated by GC column were identified by interpreting the corresponding EI ion mass spectra. The products from 9-alkoxy methyl linoleate radical were methyl octanate, 2,4-decadienal, nonanoic acid, 9-oxo-methyl ester, and its further oxidation product, nonanedioic acid, monomethyl ester. All of them formed through a pathway of beta-cleavage. The products from 13-alkoxy methyl linoleate radical were tridecanoic acid, 9, 11-diene-13-oxo-methyl ester, hex anal, and its further oxidation product, hexanoic acid. They were also formed through a mechanism of beta-cleavage. The fourth product from 13-alkoxy methyllinoleate radical was 13-keto-9, 11-octadecadienoic acid, methyl ester, which was obtained through a pathway of keto formation. Observation of their concentrations in the samples at different autoxidation periods revealed the time-course of formation of these products.

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Dufková, Veronika. "Stanovení perfluorovaných polutantů metodou GC a GC-MS." Master's thesis, 2007. http://www.nusl.cz/ntk/nusl-369029.

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wen, Shan-Shy, and 文上賢. "Comparison of Analytical Performance between Portable GC/MS and Desktop GC/MS." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/50036798931714782105.

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碩士
中原大學
化學研究所
97
Gas chromatography/mass spectrometry (GC/MS) is reliably used analytical technique for the microanalysis of organic vapor or poisonous chemical material including chemical weapons agent (CWA). In recent years poisonous disaster first respond agency and national chemical corps import new generation of GC/MS simultaneously, That are aimed at detecting and recognizing the name and the classification of poisonous chemical material at the first time, and provide analysis of damage and operational proposal for the commander, when poisonous disaster and chemical terrorism incident occurred. This research prepared benzene, disulfide carbon, acetaldehyde, acetonitrile and dichloromethane into different mixtures, and made a comparison of analyzing single reagent and mixed agent between desktop GC/MS and portable GC/MS in order to realize the difference of the analytical performance of these equipments. The result obtaired form disulfide carbon and dichloromethane determination indicated that the operators beed more skillful on analytical technique or using different columns. The main ion fragments of poisonous chemical material which are average below 45(m/z) are often ignored and therefore affect the determination of analytical technique. Obviously the separation abilioy of columns of portable GC/MS is not as good as desktop GC/MS. Using portable GC/MS to preliminary detect at first responding and then desktop GC/MS is used further to analyze the samples. Comparing sketch of portable GC/MS and desktop GC/MS could determine the classification of poisonous chemical material accurately.

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