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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Caracterização qualitativa do perfil volátil de vinhos espumantes brasileiros elaborados com um assemblage inovador submetidos a diferentes condições de segunda fermentação

Palma, Aline Schwertner January 2014 (has links)
Os vinhos espumantes elaborados pelo método Tradicional são elaborados, comumente, a partir das uvas Chardonnay, Pinot Noir, Chadonnay, Riesling, Viognier, Trebbiano e Pinot Noir e os componentes voláteis destes espumantes já têm merecido a atenção de diversos estudos científicos. Entretanto, vinhos espumantes produzidos a partir de outros varietais de uvas ainda não foram alvo de pesquisas científicas. A segunda fermentação ocorre dentro da garrafa e acaba por conferir uma maior complexidade aromática ao espumante produzido pelo método Tradicional, devido ao contato do vinho com as leveduras em meio redutor, por um determinado período de tempo. Isto acontece devido aos produtos secundários do metabolismo das leveduras, durante a conversão de açúcares em etanol e dióxido de carbono. Esta conversão depende dos nutrientes adicionados, chamados adjuvantes de fermentação, bem como da espécie de levedura utilizada, visto que cada levedura possui um metabolismo diferente para a utilização dos nutrientes e açúcares presentes no vinho base. Assim, objetivou-se, neste trabalho, caracterizar os componentes voláteis de vinhos espumantes de uma vinícola gaúcha, que emprega um assemblage inovador, empregando uvas Chadonnay, Riesling, Viognier, Trebbiano e Pinot Noir. Do assemblage deste vinho base utilizou-se, para segunda fermentação, duas espécies de leveduras comerciais: Saccharomyces cerevisiae e Saccharomyces bayanus. Para cada levedura utilizada na fermentação do vinho base, oito diferentes adjuvantes de fermentação foram empregados. A determinação dos compostos voláteis se deu através da técnica de microextração em fase sólida no modo headspace (HS-SPME) e cromatografia gasosa acoplada a detector de espectrometria demassa quadrupolar (GC/MS). Ao total, 25 compostos foram tentativamente identificados nos vinhos em estudo, sendo os compostos majoritários citados a seguir, com sua possível contribuição para o aroma destes vinhos: octanoato de etila (aroma de fruta), álcool isoamílico (aroma de banana), ácido octanoico (aroma de pimentão) e álcool feniletílico (aroma floral). O fenetil fenilacetato, um dos compostos minoritários tentativamente identificado em alguns dos vinhos, até então não reportado em vinho espumante, é associado a aroma frutado. Não foi possível distinguir subgrupos entre os 16 vinhos em estudo, provenientes de diferentes condições na segunda fermentação, quando as áreas cromatográficas dos compostos voláteis destes 16 vinhos foram submetidas a análise de cluster. Isto implica em que, nas condições experimentais deste estudo, não foi possível distinguir os voláteis dos vinhos fermentados (2ª fermentação) com S. cereviseae e os fermentados com S. bayanus. A mesma análise de cluster mostrou a subdivisão dos compostos voláteis dos 16 vinhos em dois grupos, os quais se distinguiram, provavelmente, devido aos diferentes adjuvantes nutricionais empregados: fosfato e Thiazote. Desta forma, através de análise qualitativa por HS-SPME-GC/MS, foi possível verificar a homogeneidade do perfil volátil dos 16 vinhos espumantes, obtidos a partir de diferentes adjuvantes de fermentação e duas espécies distintas de leveduras Saccharomyces sp, além de comparar os componentes voláteis presentes nestes espumantes com aqueles reportados na literatura para outros vinhos espumantes. / Sparkling wines elaborated by Traditional Method are usually produced by the grapes Chardonnay, Pinot Noir and Riesling, in which the volatile compounds of these sparkling wines have been calling attention to scientific studies. However, sparkling wines produced by other varietal grapes have not been a target of scientific research yet. The second fermentation occurs inside the bottle, in which confer a greater aromatic complexity to the sparkling wine produced by Traditional Method, due to the contact of it with lees in a reducing medium during a certain period of time. This happens due to secondary products of yeast metabolism, during the conversion of sugar in ethanol and carbon dioxide. This conversion depends on the nutrients added, called fermentation adjuvants, as the yeast used, since each one has a different metabolism for using this nutrients and sugars presented in the base wine. Thus, this work aims to characterize the volatile compounds of a south Brazilian winery, which use an innovative assemblage, using the grapes Chardonnay, Riesling, Viognier, Trebbiano and Pinot Noir. To the base wine, two different commercial yeasts were added: Saccharomyces cerevisiae and Saccharomyces bayanus to the performance of second fermentation. To each yeast used for fermenting the base wine, eight different fermentation adjuvants were used. The determination of volatile compounds were performed by Headspace solid-phase Microextraction (HS-SPME) and gas chromatography coupled to a mass quadrupole spectrometry (GC/MS). In total, 25 compounds were tentatively identified in the studied sparkling wines, being the majority listed as it follows, with their possible contribution to these sparkling wines aroma: ethyl octanoate (fruity), isoamyl alcohol (banana), octanoic acid (green pepper), and phenethyl alcohol (flower). Phenethyl phenylacetate, one of the minority compounds tentatively identified in some of the sparkling wines, is associated with fruity aroma. It was not possible to distinguish subgroups from different conditions during the second fermentation, when submitting the chromatographic areas of volatile compounds to cluster analysis. It implies that, under the experimental conditions of these study, it was not possible to differ the volatile compounds of the fermented (2nd fermentation) with S. cerevisiae and those which were fermented with S. bayanus. The same cluster analysis showed a subdivision of volatile compounds of the 16 wines in two groups, in which were probably distinguished due to the different nutritional adjuvants used: phosphate and Thiazote. Thus, throughout qualitative analysis by HS-SPME-GC/MS, it was possible to verify the homogeneity of volatile profile of the 16 sparkling wines, obtained by different fermentation adjuvants and two different yeast species of Saccharomyces sp, besides the comparison of volatile compounds presented in these sparkling wines with those others reported in the literature.
92

Aplicações forenses do Probe Electrospray Ionization Mass Spectrometry com filme de polipirrol / Forensic aplications of Probe Electrospray Ionization Mass Spectrometry using polypyrrole films

Bernardo, Ricardo Alves 14 July 2017 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2017-08-09T19:01:05Z No. of bitstreams: 2 Dissertação - Ricardo Alves Bernardo - 2017.pdf: 2682606 bytes, checksum: f8d1278bd90c5b2d1870dc822ba29d59 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-08-10T13:37:03Z (GMT) No. of bitstreams: 2 Dissertação - Ricardo Alves Bernardo - 2017.pdf: 2682606 bytes, checksum: f8d1278bd90c5b2d1870dc822ba29d59 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-10T13:37:03Z (GMT). No. of bitstreams: 2 Dissertação - Ricardo Alves Bernardo - 2017.pdf: 2682606 bytes, checksum: f8d1278bd90c5b2d1870dc822ba29d59 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-07-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this study, we developed a solid phase microextraction (SPME) method to extract Cocaine, Lisergic Acid Diethylamide (LSD), Methamphetamine (MA) and [3,4 – Methylenedioxymethamphetamine] (MDMA), which allowed the direct analysis by MS in a Probe Electrospray Ionization Mass Spectrometry (PESI-MS). PPy fibers were deposited on a platinum wire. These fibers were subjected to drug extraction from biological fluids employing SPME principles. After that, the coated platinum wire was positioned in front of the MS and then a high voltage (HV) was applied on it. At the same time, methanol (formic acid 0,1%) was used to assist the analytes desorption, ionization, and detection. Parameters as number of cycles in electrochemical process, pH, temperature of extraction and matrix effect were evaluated. The coated PESI-MS method presented linearity in a concentration range from the limit of quantification (LOQ) to 500 ng.L-1 (ppb). The LOQ values ranged from 2 ng.L-1 to 10 ng.L-1. The interday precision presented values from 0.8 to 9.6% with accuracy ranging from -0.6 to 13.7%. The intraday precision obtained values varied from 1.7 to 10.8% with accuracy ranging from -2.4 to 14.0%. The absolute recovery was also evaluated and presented values from 97.6 to 114.0%. The proposed method is a promising alternative to fast sampling and analysis for avoiding laborious process, and for showing precision and accuracy according to the values proposed by ANVISA. / Para este trabalho foi desenvolvido um sistema SPME para extração e análise direta de Cocaína, Dietilamida do Ácido Lisérgico (LSD), [3,4 – Metilenodioximetanfetamina] (MDMA) e Metanfetamina (MA) por espectrometria de massas (MS) em uma fonte de ionização Probe Electrospray Ionization Mass Spectrometry (PESI-MS). Fibras de polipirrol (PPy) foram eletrodepositadas em um fio de platina, essas fibras foram submetidas à extração de drogas em fluidos biológicos empregando os princípios da SPME. Após a extração, o fio de platina contendo o revestimento de PPy foi posicionado na entrada do espectrômetro de massas, uma diferença de potencial (ddp) foi aplicada ao fio e com auxílio de uma solução de metanol (0,1% de ácido fórmico), observou-se a dessorção e detecção dos analitos previamente extraídos. Parâmetros como o número de ciclos de eletrodeposição e pH de extração foram avaliados. O método se mostrou linear na faixa de concentração do LOQ a 500 ng.L-1 (ppb). Os valores de LOQ variaram de 2 ng.L-1 a 10 ng.L-1. A precisão inter-dias do método foi avaliada e mostrou valores entre 0,8 a 9,6% com exatidão de -0,6 a 13,7%. A precisão intra-dias apresentou valores de 1,7 a 10,8% com exatidão de -2,4 a 14.0%. A recuperação do método também foi avaliada e apresentou valores de 97,6 a 114,0%. O método proposto apresenta-se como alternativa promissora para rápida extração e análise direta sem a realização de procedimentos dispendiosos e laboriosos, com precisão e exatidão dentro dos parâmetros propostos pela ANVISA.
93

Microextração em fase sólida e cromatografia gasosa bidimensional abrangente = aplicações em lipidômica / Solid phase microextraction and comprehensive two-dimensional gas chromatography : applications in lipidomics

Hantao, Leandro Wang, 1986- 06 October 2011 (has links)
Orientador: Fabio Augusto / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-19T10:51:34Z (GMT). No. of bitstreams: 1 Hantao_LeandroWang_M.pdf: 3862279 bytes, checksum: 7d8b474b736814564a1145814b69d5e9 (MD5) Previous issue date: 2011 / Resumo: Neste trabalho foram desenvolvidas metodologias para a análise de lipídios na forma de seus ésteres metílicos de ácido graxo (FAME) em diversas matrizes. Para isso foram empregadas e otimizadas de forma multivariada técnicas de derivatização dos lipídios por transesterificação por catálise básica, seu isolamento e concentração por Microextração em Fase Sólida (SPME) e análise por Cromatografia Gasosa Bidimensional Abrangente (GCxGC). A partir do perfil de extração foi escolhida a fibra comercial com revestimento de poli(dimetilsiloxano) (PDMS) com espessura de filme de 7 mm. O tempo de extração escolhido foi de 10 min pois atingiu a condição de sistema estacionário. Os parâmetros cromatográficos, tais como a programação de temperatura do forno, período de modulação e tipo de fase estacionária das colunas utilizadas no protótipo GCxGC, foram também otimizados. Além disso, durante o progresso deste trabalho, foi desenvolvido o primeiro protótipo brasileiro de GCxGC acoplado a um Espectrômetro de Massas com Analizador Quadrupolar rápido (GCxGCxqMS). Dentre os parâmetros operacionais do qMS, foram otimizados o intervalo de varredura do analizador quadrupolar e sua frequencia de aquisição. O sistema GCxGCxqMS foi empregado para a identificação dos FAME presentes nas amostras empregadas neste estudo, através do uso das informações obtidas pelos espectros de massas obtidos das amostras, com padrões analíticos e combinando o uso de índices de retenção (LTPRI) e da estrutura cromatográfica. Neste trabalho, devido ao incremento em detectabilidade e sensibilidade, foi possível observar diversos FAME comumente não detectados por Cromatografia Gasosa Convencional (GC), como FAME de comprimento ímpar de cadeia e a presença de agrupamento metila no carbono 2 (-br2). Além disso, em virtude da baixa abrangência do banco de dados disponíveis, foi possível, e necessário, criar um banco de dados com índices de retenção para análise de lipídios. Espera-se que estas metodologias desenvolvidas e os resultados apresentados possam ser empregados como ferramenta em estudos de lipidômica e aplicações correlatas / Abstract: The aim of this project was to develop alternative methodologies for lipidomic studies and related applications. A method for the analysis of lipids in different samples such as waxes, edible oils and cheek cells was developed. The isolation and concentration of the analytes was performed by Solid Phase Microextraction (SPME) combined with Comprehensive Two-dimensional Gas Chromatography (GCxGC). Firstly, the base-catalysed transesterification of the lipids into their respective fatty acid methyl esters (FAME) was optimized according to a multivariate model. Thus, the sample prepation was optimized considering the thickness of the coating and their respective extraction profiles. The choosen commercial coating was a poly(dimethylsiloxane) (PDMS) with 7 mm film thickness, the extraction time was 10 min where stationary state conditions were achieved. Secondly, chromatographic parameters were also optimized, such as the temperature programming, modulation period, the identity of the first and second dimensional columns used in GCxGC prototype. During the current study, the first brazillian prototype of a GCxGC coupled to a mass spectrometer with a rapid quadrupolar analyzer was developed (GCxGCxqMS). Also, the scan interval and acquisition frequency of the qMS were optimized. For the identification of the analytes similarity searches for mass spectra, analytical standards and the combination retention indexes with chromatographic structuration were used. Additionally it was possible to detected and identify FAME which couldn't be detected by conventional GC such as odd numbered chain length and branched FAME. Moreover, elution pattern of a branched FAME was reported, specifically the FAME with a methyl group in the carbon 2 (-br2). Because of the restricted content of the retention indexes and mass spectra database, the construction of a database with retention indexes for lipid analysis was built. Hence the ultimate goal of the current study is to present the potencial and applicability of SPME for lipidomic studies and related applications / Mestrado / Quimica Analitica / Mestre em Química
94

Determinação de off-flavours em carne e gordura suína por GCxGC combinada a SPME / Off-flavors determination in pork meat and fat by GCxGC combined with SPME

Braga, Soraia Cristina Gonzaga Neves, 1986- 21 August 2018 (has links)
Orientador: Fabio Augusto / Dissertação ( mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-21T16:42:20Z (GMT). No. of bitstreams: 1 Braga_SoraiaCristinaGonzagaNeves_M.pdf: 1977454 bytes, checksum: fb33fc10b38aaf44e885e8b0b197c7ba (MD5) Previous issue date: 2012 / Resumo: A carne de porco é a proteina mais consumida no mundo. Para ser consumida a carne necessita de um padrão de qualidade e um dos problemas que afeta esta qualidade é o surgimento de odores desagradáveis. Estes odores, conhecidos como boar taint, são causados principalmente pela presença de androstenona e escatol em níveis maiores que 1,00 mg g e 0,25 mg g, respectivamente, em gordura suína. Os métodos existentes para determinação destes compostos são dispendiosos e não geram resultados em tempos satisfatórios para análise de rotina. Neste trabalho foi proposto um novo método para determinação de androstenona e escatol em gordura suína que se baseia na utilização de microextração em fase sólida (SPME) e cromatografia gasosa bidimensional abrangente (GC xGC). Para isso foi realizada uma otimização univariada do tipo de fibra e agente saponificante e posteriormente uma otimização multivariada, envolvendo concentração de saponificante, tempo de saponificação, temperatura e tempo de extração. O método otimizado foi validado sob os parâmetros de limites de detecção e quantificação, linearidade, precisão e exatidão. Para o escatol é possível a quantificação de amostras com quantidades menores que as detectadas sensorialmente (0,25 mg g), com precisão e exatidão, mas para a androstenona, é possível apenas detectar a presença ou não deste analito. Após todo o desenvolvimento e validação do método, este foi aplicado em sete amostras de toucinho cedidas pelo ITAL / Abstract: Pork is the must consumed protein the world. For consumpted, the meat needs a quality standard and one of the problems concerning the quality of pork meat are off-flavours. These off-flavores, called boar taint are caused by the presence of two compounds, skatole and androstenone, in levels superior to 1.00 and 0.25 mg g, respectively in pig fat. In order to determine these flavors is necessary to know the concentrations of androstenone and skatole in pig fat. There are specific methods to analyse these compounds, but they spend a lot of time and require a great number of clean-up steps process. In this work, a faster and cleaner method was proposed to determine the presence of androstenone and skatole in pig fat, based in the solid phase microextraction (SPME) and comprehensive bidimensional gas chromatography (GC xGC). A univariate optimization considering the kind of fibre coating and hydrolysis agent was performed. Later a multivariate optimization was developed to determine the concentration of hydrolysis agent, time of saponification and temperature and time of extraction. The best conditions found for the method were used for its validation. The quantification and detection limits, linearity, accuracy and precision were determined. For skatole it is possible to quantify samples at smaller quantities than those found sensorially (0.25 mg g), with precision and accuracy, but for androstenone the method only detects its presence or absence in the analyte. After all the development and validation of the method, it was implemented with seven samples of pig fat, courtesy of ITAL (Instituto de Tecnologia de Alimentos) / Mestrado / Quimica Analitica / Mestra em Química
95

Germania- and silica-based perfluorinated and non-fluorinated sol-gel sorbents for capillary microextraction in chromatographic analysis

Seyyal, Emre 06 April 2017 (has links)
Sample preparation is the most time-consuming and error-prone step in chemical analysis. Miniaturization and automation of the sample preparation equipment eliminating or reducing the use of hazardous organic solvents, online hyphenation of sample preparation with analytical instruments in a cost-effective way are important factors that need to be considered to design and implement innovative sample preparation techniques and strategies. Solid-phase microextraction (SPME) is a simple, environmentally benign technique well suited for hyphenation with analytical instruments. However, poor coating stability is a significant drawback of SPME employing conventionally prepared coatings. This shortcoming arises from the lack of chemical bonding between the sorbent coating and the substrate. Introduction of sol-gel coatings in SPME greatly improved thermal stability and solvent stability in SPME, by providing direct chemical bonding between substrate and the sol-gel coating. In traditional fiber format of SPME (where the sorbent coating is placed on the outer surface of an end-segment of the fiber) the coating remains vulnerable to mechanical damage. Capillary microextraction (CME), the capillary format of SPME (also known as in-tube SPME), allows to overcome this shortcoming by securing the sorbent coating on inner walls of the capillary. This dissertation focuses on the development and systematic investigation of novel silica- and germania-based perfluorinated and non-fluorinated sol-gel sorbents in the form of CME surface coatings: their preparation, material characterization, CME performance evaluation, preconcentration and recovery of various analytes including environmental pollutants. This research established that germania-based sol-gel sorbents are characterized by superior microextraction performance than analogous silica-based sorbents. This enhanced performance provided by germania-based sol-gel sorbents may be explained based on thermogravimetric analysis suggests that higher carbon loading on germania-based sol-gel sorbents. Germania-based phenyl- (Ph), phenethyl- (PhE), octyl- (C8), octadecyl- (C18) and cyclohexenylethyl- (ChE) ligand-containing sol-gel sorbents were prepared and various pollutants with aromatic rings (such as aromatic ketones, aldehydes and polycyclicaromatic hydrocarbons) were extracted and analyzed by CME-GC and CME-HPLC. It was observed that sol-gel sorbents containing aromatic ligands (PhE and Ph) provided superior microextraction performance for the analytes with aromatic ring(s) in their structure, than the sorbents with aliphatic ligands (C8 and C18). Investigation of sol-gel sorbents containing hydrophobic perfluorooctyl (PF-C8) and perfluorododecyl (PF-C12) ligands revealed that PF-C8 and PF-C12 sol-gel sorbents provided ~ 3 times higher microextraction efficiency (measure in terms of specific extraction, SE) than corresponding non-fluorinated counterparts, C8- and C12-, respectively. The synthesis and design of silica- and germania-based dual ligands sol-gel sorbents simultaneously providing superhydrophobicity and π-π interactions with analytes represent a significant accomplishment of this research. Such sorbents contained a PF-C12 and PhE ligands incorporated in sorbent chemical structure. In this case, perfluoro- group provided enhanced hydrophobic interaction and PhE group provided π-π interaction with the analytes. Combination of such interactions proved to be quite effective in the microextraction of alkylbenzenes and related compounds. Dual-ligand sol-gel sorbents with both equimolar and non-equimolar ligand concentrations were prepared. Experimentally it was established that sorbents with higher perfluorinated alkyl ligand concentrations had higher affinity for aliphatic hydrocarbons; however; when PhE concentration was higher, the dual-ligand sorbent showed enhanced affinity for aromatic compounds. The prepared sol-gel sorbents were characterized by less than 5% run-to-run RSD values, and also less than 5% capillary-to-capillary RSD values, which indicate that the sol-gel technique used in sorbent preparation was highly reproducible. The prepared sol-gel sorbents also showed that their performance does not deteriorate under aqueous saline matrix; therefore, it could be useful in the microextraction of pollutants from ocean water.
96

Persistência de fragrância em cabelo : influência das propriedades físico-químicas e da encapsulação de óleo essencial / Persistence of fragrance in human hair : role of physicochemical properties and encapsulation of perfume oil

Pavani, Matheus, 1989- 24 August 2018 (has links)
Orientadores: Marcos José Salvador, Inés Joekes / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-24T13:48:04Z (GMT). No. of bitstreams: 1 Pavani_Matheus_M.pdf: 3408518 bytes, checksum: bdb62efa906a9a04de3a371f12ecd0f0 (MD5) Previous issue date: 2014 / Resumo: A fragrância de um produto cosmético é um aspecto importante para determinar seu desempenho. É crescente o emprego de produtos naturais, bem como de fragrâncias encapsuladas na indústria cosmética. Entretanto, há escassos estudos descrevendo o perfil de liberação de fragrâncias a partir de matrizes complexas, muito menos a partir de cabelos. Este trabalho investigou a interação de uma fragrância livre ou encapsulada em cabelos virgens caucasianos. Óleo essencial de capim-limão (Cymbopogon citratus DC. Stapf), livre ou encapsulado, foi empregado como fragrância em formulações de xampu e condicionador sem enxágue. O processo de encapsulação deu-se por meio de polimerização in situ da resina de melamina-formaldeído, variando-se parâmetros reacionais como velocidade de agitação, acidificação do meio e teor de óleo essencial. Os perfis de liberação da fragrância proveniente de mechas de cabelo, tratadas com as formulações obtidas, foram tomados ao longo do tempo (0 a 12 h), com amostragem por microextração em fase sólida (SPME) e análise por cromatografia gasosa acoplada à espectrometria de massas (CG-MS). A liberação das substâncias da fragrância na forma livre variou em função do tipo de formulação cosmética (xampú ou condicionador sem enxágue). Neste caso, a persistência delas na fibra capilar se correlacionaou com seus valores de coeficiente de partição óleo-água (logP). Micropartículas esféricas (dH = 9 ± 1 µm) e rendimento de processo de 86 % foram obtidos com decaimento lento de pH aliado a agitação vigorosa durante a reação de formação. Estas partículas promoveram liberação sustentada para os constituintes linalol e citral (12 e 2 vezes mais duradoura em relação à forma livre, respectivamente), mostrando um aumento da persistência da fragrância encapsulada quando inserida em formulação sem enxágue, e modificando as forças de interação cabelo¿fragrância / Abstract: Fragrance plays an important role in the performance of a cosmetic formulation. The use of natural products in the cosmetic industry as well as encapsulated fragrances is growing. However, there are few studies describing the release profile of fragrances from complex matrices, much less from Human hair. This work investigates the interaction of a fragrance composition (free or encapsulated) with un-treated Caucasian hair. Lemongrass essential oil (Cymbopogon citratus DC. Stapf) was employed as fragrance in rinse-off shampoo or leave-on formulations. Encapsulation was performed by in situ polymerization of melamine and formaldehyde monomers, changing reaction parameters such as stirring rate, pH decay, and essential oil content. Fragrance release profiles from the hair tresses treated with the abovementioned formulations were acquired over the time (0 to 12 h) with a solid phase microextraction (SPME) device, and analyzed by gas chromatography-mass spectrometry (GC-MS). The release of free form fragrance constituents depended on the type of cosmetic formulation (shampoo or leave-on), but its persistence on hair fiber was correlated with its oil-water partition coefficient (logP) value in both cases. Spherical microparticles (dH = 9 ± 1 µm) and 86 % yield were obtained with slow pH decay combined with vigorous stirring during the encapsulation process. Sustained release of the fragrant components linalool and citral (12 times and twice longer-lasting compared to the free form, respectively) was found, showing an increased persistence of the encapsulated fragrance when inserted in the leave-on formulation and changing perfume¿hair interaction / Mestrado / Fármacos, Medicamentos e Insumos para Saúde / Mestre em Biociências e Tecnologia de Produtos Bioativos
97

Advances in Solid Phase Microextraction for the Analysis of Volatile Compounds in Explosives, Tire Treatments, and Entomological Specimens

Kranz, William D. 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Solid phase micro-extraction is a powerful and versatile technique, well-suited to the analysis of numerous samples of forensic interest. The exceptional sensitivity of the SPME platform, combined with its adaptability to traditional GC-MS systems and its ability to extract samples with minimal work-up, make it appropriate to applications in forensic laboratories. In a series of research projects, solid phase micro-extraction was employed for the analysis of explosives, commercial tire treatments, and entomological specimens. In the first project, the volatile organic compounds emanating from two brands of pseudo-explosive training aids for use in detector dog imprinting were determined by SPME-GC-MS, and the efficacy of these training materials was tested in live canine trials. In the second project, the headspace above various plasticizers was analyzed comparative to that of Composition C-4 in order to draw conclusions about the odor compound, 2- ethyl-1-hexnaol, with an eye toward the design of future training aids. In the third, automobile tires which had participated in professional race events were analyzed for the presence of illicit tire treatments, and in the fourth, a novel SPME-GC-MS method was developed for the analysis of blowfly (Diptera) liquid extracts. In the fifth and final project, the new method was put to the task of performing a chemotaxonomic analysis on pupa specimens, seeking to chemically characterize them according to their age, generation, and species.
98

Differentiation of Ignitable Liquids in Fire Debris Using Solid-Phase Microextraction Paired with Gas Chromatography-Mass Spectroscopy and Chemometric Analysis

McKeon, Amanda Marie January 2019 (has links)
No description available.
99

The Development of Alternative Green Sample Preparation Approaches for Analysisof Unconventional Environmental Pollutants

Emmons, Ronald V. 15 June 2023 (has links)
No description available.
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Synthesis of New Classes of Ionic Liquids and Polymeric Ionic Liquids and their Applications in Microextraction Techniques

Joshi, Manishkumar Dilipkumar January 2013 (has links)
No description available.

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