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

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

Orientador: Isabel Cristina Sales Fontes Jardim / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T03:19:20Z (GMT). No. of bitstreams: 1 Faria_LeonardoJardimdaSilva_M.pdf: 547743 bytes, checksum: c807d29f792ecf6c57e17ca59816fdfe (MD5) Previous issue date: 2004 / Mestrado / Quimica Analitica / Mestre em Química

Les usines de l’amont du cycle du combustible nucléaire, génèrent des effluents industriels faiblement chargés en uranium. La récupération de l’uranium de ces effluents vise à les décatégoriser (diminution de la radioactivité) et à valoriser l’uranium recyclé. L’acide sulfurique est majoritairement utilisé dans l’amont du cycle du combustible. Dans ces conditions, l’uranium est sous forme de complexes de sulfates d’uranyles qu’il convient d’extraire sélectivement vis-à-vis d’ions compétiteurs comme le Mo ou le Fe. Plusieurs procédés peuvent être envisagés : précipitation, extraction liquide-liquide et extraction sur supports solides. Cette dernière technique est particulièrement attractive pour des solutions faiblement chargées en uranium : elle est éco-responsable (évite la manipulation de solvants organiques), les procédés sont compacts et nécessitent peu de manipulations (i.e. extraction sur lit fixe). Parmi les supports solides à forts potentiels, les silices mésoporeuses occupent une place de choix de par leur grande surface spécifique, leur facilité de synthèse et leur facilité de caractérisation.Cette thèse se propose d’évaluer l’extraction d’uranium en milieu sulfurique par l’utilisation de silices hybrides mésoporeuses au sein desquelles sont greffées des molécules extractantes sélectives. Dans un premier temps, différentes molécules extractantes ont été sélectionnées, synthétisées puis greffées sur une silice commerciale afin d’évaluer les propriétés extractives de ces différentes familles d’extractant. Les N,N-carbamoylalkylphosphonates ont été identifiées comme étant des molécules intéressantes en terme de propriétés extractives. De plus, cette étude souligne la nécessité d’avoir un monoacide sur le groupement phosphonate et montre l’importance des chaines alkyles aussi bien sur le phosphonate que sur le groupement amide. A la suite de ce travail, l’impact du diamètre de pore des supports de silice sur la configuration de la partie organique greffée et sur les propriétés d’extraction de l’uranium a été mis en évidence. Une gamme de porosité (entre 3 et 20 nm) pour laquelle les matériaux hybrides sont homogènes et présentent une bonne efficacité d’extraction a été identifiée. Pour parfaire la compréhension des mécanismes d’extraction via les supports hybrides, une étude paramétrique (pH, force ionique, présence d’éléments compétiteurs) a été menée en parallèle d’analyses spectrométriques (EXAFS, FT-IR, Raman, DRX). Ces techniques ont permis de proposer un mécanisme d’extraction au sein du solide impliquant deux diamido-phosphonates par uranyle. Les résultats obtenus à l’échelle moléculaire sont en accord et confortent les propriétés macroscopiques observées lors de l’analyse paramétrique. / Nuclear industries are perpetually looking for technical, economic and environmental progresses. Important volumes of acidic waste are generated by nuclear plants of the front end. The extraction of uranium from these solutions is required to decontaminate effluents (decrease of the radioactivity) and value uranium (reincorporation in the cycle). Uranium leaching is mostly achieved using sulfuric acid leading to the production of aqueous effluents that contain a large grade of sulfate complexes. In such conditions, uranyl sulfate complexes constitute the predominant uranium species in solution and its extraction represents a real scientific and technological challenge. Commonly, precipitation, solvent extraction or solid phase extraction are used. The last one is particularly adapted for low grade solutions due to it weak environmental footprint (no solvent are handling) and the facility of the process involved (i.e. fixed bed column). Among the available solid-phase extraction candidates, hybrid mesoporous silicas get a crucial part. They develop a very high specific surface areas and a driven porosity which give them a high potential of extraction capacities.In this manuscript the tailoring and the evaluation of hybrid mesoporous silicas have been investigated. Firstly, the work focus on the organic part grafted by post-synthetic pathway, the N,N-dialkylcarbamoylphosphonate based molecules have been identified to get interesting extraction properties. This study emphasizes that acid groups are required and that alkyl substituents get a real importance in the extraction efficiency. On the second hand, the role of pore size has been investigated. The results obtained disclosed that pores size diameters directly impact the grafting ratio as well as the homogeneity of the material: (1) materials with a pore size below 3 nm are heterogeneously functionalized due to steric issues, (2) a homogeneous organic monolayer grafted onto the silica skeleton occurs when the pore size ranges from 3 nm to 20 nm and (3) functionalization of material having pore size above 30 nm results in an organic multilayer covalently linked to the surface. The organic self-organization drives the extraction efficiency, only monolayers lead to promising results. At the saturation state, two molecules are required to extract one uranyl ion. To describe the molecular scale of the uranyl complex onto the solid, the local structure has been investigated by a parametric study and spectroscopic techniques (IR, EXAFS and DRX). Results reveal that two diamido-phosphonates are involved in the uranyl extraction. By this work, it is shown how the molecular scale helps to understand the macroscopic phenomena.Finally, continuous extraction in a fixed bed column confirms the extractive properties obtained in batch mode experiments and points out the potential of such material to be reused several times without any damages.

L'analyse des lanthanides à l'état de trace dans les matrices environnementales requiert souvent une étape de purification et de préconcentration. L'extraction sur phase solide (SPE) est la technique la plus utilisée dans le domaine du traitement de l'échantillon. Cette thèse a consisté à développer des polymères à empreintes ioniques (IIP) pour l'extraction sélective des lanthanides (Ln3+). Tout d'abord, des IIP ont été préparés selon l'approche de piégeage en utilisant le 5,7-dichloroquinoline-8-ol, un ligand non vinylique. La perte de ce ligand, supposé piégé, durant les étapes d'élimination de l'ion empreinte et de sédimentation succédant à la polymérisation a été démontrée en HPLC-UV. Cette perte non répétable a entraîné un manque de répétabilité des profils SPE sur deux IIP préparés dans les mêmes conditions. Cela a permis de démontrer que cette approche de synthèse pour des IIP n'était pas adéquate. Ensuite, des IIP ont été synthétisés par immobilisation chimique en utilisant l'acide méthacrylique comme monomère vinylique. La répétabilité des étapes de synthèse et d'extraction a été démontrée. Une sélectivité pour l'ensemble des lanthanides a été obtenue et des applications avec des échantillons réels ont été faites avec succès. Enfin, des IIP obtenus par immobilisation chimique d'acide méthacrylique et de 4-vinylpyridine comme monomères ont été synthétisés avec comme ion empreinte soit un Ln3+ léger (Nd3+) soit un Ln3+ lourd (Er3+). Des sélectivités identiques de ces IIP pour l'ensemble des Ln3+ ont été obtenues dans les deux cas. Cependant, cette sélectivité a pu être modulée en changeant la nature et le pH de la solution de lavage utilisée dans le protocole SPE. / The analysis of the lanthanide ions present at trace level in complex environmental matrices requires often a purification and preconcentration step. The solid phase extraction (SPE) is the most used sample preparation technique. To improve the selectivity of this step, Ion Imprinted Polymers (IIPs) can be used as SPE solid supports. The aim of this work was the development of IIPs for the selective extraction of lanthanide ions from environmental samples. In a first part, IIPs were prepared according to the trapping approach using 5,7-dichloroquinoline-8-ol as non-vinylated ligand. For the first time, the loss of the trapped ligand during template ion removal and sedimentation steps was demonstrated by HPLC-UV. Moreover, this loss was not repeatable, which led to a lack of repeatability of the SPE profiles. It was then demonstrated that the trapping approach is not appropriate for the IIPs synthesis.In a second part, IIPs were synthesized by chemical immobilization of methacrylic acid as vinylated monomer. The repeatability of the synthesis and the SPE protocol were confirmed. A good selectivity of the IIPs for all the lanthanide ions was obtained. IIPs were successfully used to selectively extract lanthanide ions from tap and river water. Finally, IIPs were synthesized by chemical immobilization of methacrylic acid and 4-vinylpyridine as functional monomers and either a light (Nd3+) or a heavy (Er3+) lanthanide ion as template. Both kinds of IIPs led to a similar selectivity for all lanthanide ions. Nevertheless, this selectivity can be modified by changing the nature and the pH of the washing solution used in the SPE protocol.

Dans le milieu interstellaire, beaucoup de molécules hydrogénées telles que CH4, NH3 ou CH3OH peuvent être dissociées, grâce à la contribution de particules cosmiques ou de photons hautement énergétiques, devenant l’une des plus importantes sources de radicaux activés. Cependant, dans le cœur de certains nuages moléculaires denses et sombres, en l’absence de ces énergies externes supplémentaires, d’autres chemins réactionnels de formation de radicaux pourraient exister sans apport d’énergie externe.Dans le travail de thèse actuel, nous avons étudié des réactions thermiquement induites impliquant de petites composés organiques et des atomes d’azote à l’état fondamental N(4S), en phase solide aux températures cryogéniques de 3 à 50 K, en utilisant une caractérisation par spectroscopie Infrarouge à Transformée de Fourier (IRTF).Nous avons montré qu’un chauffage progressif entre 3 et 10 K permet d’induire la mobilité des atomes d’azote dans l’échantillon solide, provoquant le processus de recombinaison N(4S)–N(4S). De telles recombinaisons engendrent la formation d’espèces réactives métastable d’azote moléculaire N2(A), lesquelles à travers un processus de transfert d’énergétie N2(A) → N(4S), conduit à la formation d’atomes d’azote excités N(4P/2D). La production de ces espèces azotées excitées en phase solide joue un rôle prépondérant dans la dissociation des espèces hydrogénées qui pourrait être la première étape dans l’origine de la complexification moléculaire du milieu interstellaire. / In interstellar medium, many hydrogen-containing molecules such as CH4, NH3 or CH3OH may be dissociated, with the contribution of cosmic ray particles or high-energy photons, becoming one of the most important sources of activated radicals. However, in the core of some dark and dense clouds, without those supplying external energies, other radicals formation pathways under non-energetic condition might exist.In the present Ph-D thesis, we have studied thermal reactions involving small organic compounds and ground state nitrogen atoms N(4S), in solid phase, at cryogenic temperatures from 3 to 50 K, using a Fourier Transform InfraRed Spectroscopy (FTIR) analysis. We have shown that gradual heating, between 3 and 10 K, allow to induce of the nitrogen atoms mobility in the solid sample stimulating the N(4S) – N(4S) recombination processes. Such recombinations result in the formation of a very reactive metastable molecular nitrogen N2(A) which through energetic transfer processes with N(4S) atoms can lead to the formation of excited nitrogen atoms N(4P/2D). The production of those excited nitrogen species in solid phase plays an important role in the dissociation of H-containing species which may be the first step in the origin of the molecular complexity of the interstellar medium.

The goal of this thesis was to develop a method for efficiently synthesizing a large suite of asymmetric oligoester ion channel-forming compounds. A solid-phase organic synthesis (SPOS) approach on Wang resin was used to generate the ion channel candidates. A follow-on goal is to survey the compounds produced to uncover structure-related controls on ion transport activity. Two classes of building blocks were used to generate the oligoesters – head groups and cores. The core building blocks were three omega-hydroxy acid derivatives six, eight and twelve carbons in length and the alcohol protected as a tetrahydropyranyl ether. The head group building blocks were either a glutaric acid monoester derivative of varying lipophilicity (12 to 16 carbon long alkyl tail) or a beta-hydroxy acid derivative; these building blocks used a tert-butyldimethylsilyl ether for alcohol protection. Optimized conditions for building block coupling, deprotection, and product cleavage were first established by the generation of dimeric and trimeric products. The building blocks were coupled using diisopropylcarbodiimide/ dimethylaminopyridine conditions. The deprotection of the tetrahydropyranyl ether group from the alcohol used a dilute acid solution in methanol and dichloromethane. A fluoride solution (from tetrabutylammonium fluoride) in tetrahydrofuran was used to deprotect the tert-butyldimethylsilyl ether group. Cleavage of the product synthesized on Wang resin was achieved by treatment with a trifluoroacetic acid/dichloromethane or ethereal hydrogen chloride solution. The products were then isolated by gel filtration. Mass spectrometry was used to identify the minor impurities which were quantified by proton nuclear magnetic resonance integrations. With the nine building blocks, many tetrameric and pentameric structures can be made, but a directed-library approach was used to address structure-activity related questions. Three pentameric oligoester products were the largest products synthesized to determine the scope and limitations of the SPOS methodology. The oligoester ion channel candidates were tested for ion transport activity using a 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt fluorescence vesicle assay. For each compound a pseudo-first order rate constant was derived at a particular concentration. A more useful normalized rate constant was calculated for an interpolated transporter concentration which allowed for transport activity comparison between compounds. The results from the fluorescence assay showed that some compounds and some isomers were substantially more active than others. There appeared to be an optimal core length and lipophilicity for relatively high activity. The aggregation of the compounds in buffer solution was probed using a pyrene fluorescence experiment. The solid-phase methodology was extended to include coupling of amino acids. A tryptophan derivative was made from one of the most active SPOS oligoester ion channel-forming compounds. The integrity of the molecules synthesized by SPOS which contain the tryptophan group could then be determined by high performance liquid chromatography. The fluorescence of the indole is quenched by acrylamide. By first equilibrating the vesicles with the tryptophan-containing oligoesters and then adding a fluorescence quencher, the resulting indole fluorescence was monitored as a function of quencher concentration. A Stern-Volmer plot was derived based on the quenching data which reported the possible orientations of the tryptophan-containing oligoester within the vesicle.

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.

Orientador: Fabio Augusto / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-08T00:55:46Z (GMT). No. of bitstreams: 1 Sartoratto_Adilson_D.pdf: 1221656 bytes, checksum: f0ebb01e44d95590f9bbda739169bb32 (MD5) Previous issue date: 2006 / Resumo: O trabalho que teve como objetivo desenvolver metodologias em Microextração em Fase Sólida para utilização em cromatografia líquida e gasosa será apresentado em dois capítulos: no primeiro capítulo a análise de pesticidas organofosforados (OPP) em amostras aquosas e infusão de plantas foi realizada por cromatografia líquida de alta eficiência/detetor de arranjo de diodos (HPLC-DAD) utilizando uma interface de dessorção para SPME e uma fibra sol-gel Carbowax 20M ormosil, produzidas em nosso laboratório. Após avaliação de desempenho da interface e eficiência da fibra sol-gel, uma metodologia de análise foi desenvolvida, avaliando-se os principais parâmetros de validação: sensibilidade, linearidade, faixa linear, exatidão, precisão, limites de detecção e quantificação. No segundo capítulo, tentamos relacionar a composição química de voláteis de plantas analisados por SPME-GC-MS com a atividade antimicrobiana de óleos essenciais. A avaliação dos voláteis foi feita utilizando-se dois tipos de fibras comerciais: PDMS e PDMS/DVB e também pela análise do óleo essencial obtido por métodos tradicionais. A atividade antimicrobiana dos óleos essenciais foi realizada pelo método da concentração mínima inibitória (MIC) com a finalidade de selecionar óleos com potencial terapêutico, em substituição às drogas existentes no mercado. / Abstract: The present work is presented in two chapters that had the scope of developing methodologies for solid phase microextraction coupled to gas and liquid chromatography. The first chapter discusses analysis of organophosphorous pesticides in water soluble samples and plant infusions by High Performance Liquid Chromatography coupled to photodiode array detector (HPLC-DAD) using a SPME desorption interface and Carbowax 20M sol-gel fiber, both produced in lab. After interface and sol-gel fiber efficiency evaluation an analysis method was developed that considered validation parameters: sensibility, linearity, linear range, accuracy, precision, detection limit, and quantification limit. In the second chapter we proposed to establish a relationship among plant's chemical volatile composition analyzed by SPME-GC-MS and antimicrobial activity of essential oils. Two commercial fibers: PDMS and PDMS-DVB were employed for essential oil analysis. Essential oils with potential therapeutic properties in substitution to known commercial drugs were chosen by minimum inhibition concentration experimental model. / Doutorado / Quimica Analitica / Doutor em Ciências

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