Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-04-13T13:00:25Z No. of bitstreams: 1 PDF - Rayanne Sales de Araújo Batista.pdf: 2799391 bytes, checksum: bfd7e21254a6a5383f8798d74f80923d (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-06-13T20:27:28Z (GMT) No. of bitstreams: 1 PDF - Rayanne Sales de Araújo Batista.pdf: 2799391 bytes, checksum: bfd7e21254a6a5383f8798d74f80923d (MD5) / Made available in DSpace on 2016-06-13T20:28:54Z (GMT). No. of bitstreams: 1 PDF - Rayanne Sales de Araújo Batista.pdf: 2799391 bytes, checksum: bfd7e21254a6a5383f8798d74f80923d (MD5) Previous issue date: 2015-03-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Retinoic acid (RA), widely used in dermatological and cosmetic products, has low stability in the presence of air and light, with sensitivity to heat and oxidation, so it is particularly important to implement the quality control of its finished products performing tests indicators of stability. Therefore, the objective was to develop an analytical method to evaluate the thermal stability of an RA cream formulation through the correlation of analytical techniques, high performance liquid chromatography with ultraviolet detection efficiency (HPLC-UV), differential scanning calorimetry (DSC) and vibrational absorption spectroscopy in the infrared Fourier transform spectroscopy (FTIR). Previously been established chromatographic conditions for development of the analytical method using HPLC-UV system, which was subjected to analytical tests specified in RE ANVISA Nº 899/2003 for validation. For evaluation of the thermal stability the cream samples were subjected to thermal stress in an oven at temperatures of 60, 70 and 80 °C and subsequently analyzed by HPLC-UV over the period of 0, 24, 48 and 72 h. DSC analyzes and FTIR spectra were carried out from the binary mixture (BM) of the RA and excipients of the cream formulation to investigate possible physical and/or chemical interactions. According to the data obtained it was possible to develop an analytical method by validated HPLC-UV, and based thereon, for analyzing and quantifying the RA content cream formulation, it has been found that from 70 ° C caused a decrease in the content of RA, and 0-order kinetics; and 80 ° C, followed a kinetic order 2 by setting up a reaction of bimolecular type. The analytical techniques DSC and FTIR showed the absence of chemical and physical interaction in most MB among the components of the formulation, except only for the carrier sodium metabisulfite. Thus, we can infer that it has a well-defined thermal behavior and compatibility of its components. / O ácido retinoico (AR), largamente utilizado em produtos dermatológicos e cosméticos, apresenta baixa estabilidade na presença de ar e luz, com sensibilidade ao calor e à oxidação, assim, é particularmente importante implementar o controle de qualidade de seus produtos acabados realizando ensaios indicadores de estabilidade. Logo, objetivou-se desenvolver um método analítico para avaliar a estabilidade térmica de uma formulação creme de AR através da correlação de técnicas analíticas, cromatografia líquida de alta eficiência com detecção ultravioleta (CLAE-UV), calorimetria exploratória diferencial (DSC) e espectroscopia vibracional de absorção na região do infravermelho com transformada de Fourier (FTIR). Previamente foram estabelecidas as condições cromatográficas para desenvolvimento do método analítico utilizando um sistema de CLAE-UV, o qual foi submetido aos testes analíticos especificados na RE ANVISA nº 899/2003 para validação do mesmo. Para avaliação da estabilidade térmica, as amostras do creme foram submetidas a estresse térmico em estufa nas temperaturas de 60, 70 e 80 º C, e posteriormente analisadas por CLAE-UV no período de 0, 24, 48 e 72 h. As análises de DSC e dos espectros de FTIR foram realizadas a partir das misturas binárias (MB) do AR e excipientes da formulação creme a fim de investigar possíveis interações físicas e/ou químicas. De acordo com os dados obtidos foi possível desenvolver um método analítico por CLAE-UV validado, e com base no mesmo, para análise e quantificação do teor de AR em formulação creme, constatou-se que a partir de 70 ° C ocorreu redução no teor de AR, e cinética de ordem 0; a 80 ° C, obedeceu uma cinética de ordem 2, configurando uma reação do tipo bimolecular. As técnicas analíticas DSC e FTIR mostraram a ausência de interação física e química na maioria das MB entre os componentes da formulação, com exceção apenas para o excipiente metabissulfito de sódio. Desta forma, podemos inferir que a mesma apresenta um comportamento térmico bem definido e compatibilidade entre seus componentes.

Nos últimos anos, a espectroscopia no infravermelho (IR) ganhou grande aceitação em diversas áreas de pesquisa por ser uma técnica rápida, simples e não destrutiva que permite a quantificação de diversos componentes químicos em amostras. Apesar de a IR resultar em valores de absorbância que auxiliam na caracterização da amostra, tal técnica acaba por gerar bancos de dados compostos por centenas, ou até milhares, de variáveis altamente correlacionadas e ruidosas, comprometendo o resultado de diversas técnicas de análise multivariada. Dentro deste cenário, esta Tese apresenta novas metodologias para seleção de variáveis, também chamada de seleção de comprimentos de onda quando aplicados em dados de IR, com o intuito de auxiliar o reconhecimento de padrões para o controle de qualidade em diversas áreas. Tais metodologias são apresentadas em três artigos onde as proposições visam à solução de problemas específicos: no primeiro artigo, amostras de erva mate são categorizadas de acordo com seu país de origem através de uma nova metodologia para seleção de variáveis Para tanto, um problema de Programação Quadrática, combinado com a Informação Mútua entre as variáveis, é utilizado para reduzir a redundância entre as variáveis retidas e maximizar sua relação com o local de origem da amostra; por sua vez, o segundo artigo adequa as proposições do primeiro artigo para um problema de predição, onde o objetivo é determinar a concentração de cocaína e adulterantes em amostras de cocaína laboratoriais e apreendidas; por fim, o terceiro artigo utiliza a estatística do teste de Kolmogorov-Smirnov para duas amostras em uma abordagem de seleção de intervalos de comprimentos de onda com o intuito de identificar falsificações em medicamentos para disfunção erétil. A aplicação dos métodos em bancos de dados com distintas características e a validação dos resultados corrobora a adequabilidade das proposições desta tese. / Over the last few years infrared (IR) spectroscopy gained wide acceptance in many research fields as a quick, simple and non-destructive technique allowing the quantification of many chemical compounds. Although IR provide many absorbance values that helps the sample characterization, this technique also generate databases comprised by hundreds, or even thousands, of highly noisy and correlated wavenumbers, jeopardizing the results of many multivariate analysis techniques. Under such scenario, this thesis presents new variables selection methodologies (also called wavenumber selection when applied in IR data) aimed to recognize patterns for quality control in many areas. Such methodologies are presented in three papers where the propositions are tailored for the solution of specific problems: on the first paper, yerba mate samples are categorized according to their country of origin through a novel variable selection methodology. Thereunto a quadratic programming problem, combined with the Mutual Information among variables, is utilized to reduce the redundancy among variables and increase their relationship with the samples’ place of origin; the second paper adequate the first paper propositions for a prediction method which aims to determine cocaine and adulterants concentration in laboratorial and seized cocaine samples; lastly, the third paper uses the two-samples Kolmogorov-Smirnov statistic in an wavenumber interval selection method aimed for the identification of counterfeit erectile dysfunction medicines. The application of the methods in databases with distinct characteristics and the results validation corroborates the suitability of this thesis propositions.

As células a combustível de etanol direto (DEFCs, Direct Ethanol Fuel Cells) são baseadas na eletro-oxidação do etanol à baixa temperatura e necessitam catalisadores à base de metais nobres, devido à cinética mais lenta para as reações de oxi-redução. Entre os catalisadores, a platina e as ligas de platina são os mais utilizados. Materiais para suportar os catalisadores são necessários a fim de reduzir a carga do mesmo empregada. Um dos suportes de catalisadores mais versáteis é o carvão ativado, e um dos mais utilizados tem sido o carvão mineral Vulcan. Recentemente, estudos têm sido realizados sobre a madeira como material precursor de carvão ativado, devido à sua sustentabilidade e também porque os materiais carbonosos obtidos têm excelentes propriedades finais. No presente trabalho, estudou-se a reação de eletro-oxidação do etanol, de catalisadores à base de Pt e PtSn suportados em biocarvões obtidos a partir da madeira Eucalyptus grandis. No início desse trabalho não havia relatos na literatura sobre o uso de carvões ativados obtidos a partir de madeira de Eucalyptus grandis como precursor. Foram utilizados dois métodos de ativação nos suportes, ativação física com CO2 e ativação química com ZnCl2. Os suportes de catalisadores foram caracterizados por análise textural, análise elementar, análise termogravimétrica e por espectroscopia de infravermelho. As técnicas empregadas para a caracterização dos catalisadores foram espectrometria de retroespalhamento de Rutherford (RBS), difração de raios-X (DRX), análise termogravimétrica (TGA), microscopia eletrônica de transmissão (MET), voltametria cíclica (VC) e caracterização espectroeletroquímica (ATR-FTIR in-situ). Os biocarvões apresentaram áreas superficiais maiores e tamanhos de poros menores do que o carvão Vulcan, independente do tratamento. A natureza do suporte influenciou nas características morfológicas dos eletrocatalisadores preparados. Com base nos resultados obtidos os catalisadores suportados nos suportes com ativação química apresentaram os melhores resultados de densidade de corrente para eletro-oxidação do etanol, com exceção do catalisador PtSn suportado no biocarvão ativado fisicamente (PtSn/BCAF). Pode-se dizer que os biocarvões são adequados para aplicações em células de combustível, podendo substituir o uso de suportes baseados em carvões minerais. A eletro-oxidação do etanol nos eletrocataliadores de PtSn nos carvões ativados ocorre principalmente através da produção de acetaldeído e ácido acético. / Direct ethanol fuel cells (DEFC) are based on ethanol electrooxidation at low-temperature and they require noble metal based catalysts, due to the slower kinetic of redox reactions. Among the catalysts, platinum and its alloys have been the most widely used. Catalysts support materials have been employed with the intent to reduce loading catalyst. One of the most versatile catalyst supports is activated carbon, and one of the most widely used is the Vulcan®, a mineral carbon. Currently, different studies have been conducted concerning wood as activated carbon precursor, because of its sustainability and its properties, like suitable porous texture, surface area and surface chemistry. In this work, it was studied ethanol electrooxidation reaction on Pt and PSn catalysts supported on biocarbon. Biocarbons were obtained from Eucalyptus grandis. Literature reports the use of carbon materials as catalyst support, however focused on carbon fibers and carbon nanotubes, without any precedent on the use of activated carbon obtained from Eucalyptus grandis until the start of this work. The carbon supports were obtained by physical activation using CO2, and chemical activation with ZnCl2. Catalyst support characterization boarded elemental analysis, texture analysis, thermogravimetric analysis and infrared spectroscopy. Techniques employed for the catalyst characterization were Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), cyclic voltammetry (CV) and spectroelectrochemical characterization (ATR-FTIR in situ). Biocarbons presended the higher surface areas and smallest pore size than the Vulcan ones, independent of the treatment. The support nature influenced on the catalyst morphology. Results showed that the catalyst on the chemically activated supports presented the best current density for ethanol electro-oxidation, except for the PtSn on the physically activated biocarbon (PtSn/BCAF). Biocarbons resulted adequate for fuel cell applications and are capable of substituting the conventional supports based on mineral carbon. Ethanol electro-oxidation on PtSn catalysts takes place through the production of acetaldehyde and acetic acid reaction mechanism.

To discover the potential of IR spectroscopy and explore the details of FTIR instrumentation, a FTIR was built from most basic parts to provide access to every aspect of a IR spectrometer including the hardware and software. The optical system followed the most widely used double-interferometer design. The software control system was developed with LabVIEW to perform data acquisition of the detectors, data processing and controls of the actuators. The FTIR built will be able to provide a full optical IR spectroscopy platform which has a complete control and data acquisition system and can be continuously improved in accuracy and resolution to reach high lab experiment class as the research keep going. The availability of the hardware setup and software source code allows updating of this system for many advanced IR spectroscopy like spatially resolved and time resolved applications. To achieve in-situ material characterization with multiple measurements, some instruments can be modified and integrated with experiments. This thesis provides a practical and useful example of measuring IR spectra and mass of the sample simultaneously during thermal reactions. This instrument was designed and build with a Fourier transform infrared spectrometer (FTIR) and a thermogravimetric analyzer (TGA). Diffuse reflectance Fourier transform (DRIFT) was equipped to a commercial FTIR to acquire the IR spectra. A micro-balance was taken from a TGA was refitted to this system to measure the sample mass. A series of LabVIEW applications was developed for the FTIR control and communication, TGA communication and temperature control. The system was successfully built and tested with calcium oxalate decomposition experiments. The data showed that the instrument has good accuracy and repeatability of both the IR and mass measurement. The analysis of the calcium oxalate data demonstrated good correlation between the IR, mass and temperature parameters.

Metal oxides in the atmosphere emitted from various natural and anthropogenic processes alter the chemical balance of the Earth's atmosphere due to heterogeneous and photochemical processes with atmospheric trace gases. Therefore, understanding the heterogeneous chemistry and heterogeneous photochemistry of atmospheric trace gases on these oxide surfaces has become vital to precisely predict the effect of mineral dust loading on the Earth's atmosphere. Among the various components of mineral dust, light absorbing oxides play a significantly important role during the daytime. The work reported herein has focused mainly on TiO2 and Α-Fe2O3. These are light adsorbing components found in atmospheric mineral dust. Apart from being a component of mineral dust, TiO2 is heavily used in a number of industrial applications ranging from uses in self-cleaning, water purification to cosmetics. These applications have led to their presence in the atmosphere as anthropogenic dust particles and in contact with the atmosphere as a stationary phase. Iron-containing particles are transferred to the atmosphere mainly from wind and volcanic activities in the form of iron-containing mineral dust and volcanic ash aerosols. Α-Fe2O3 is the most stable iron containing compound found in the Earths' crust which constitutes in significant amounts in mineral dust. The presence of these oxide surfaces in the atmosphere can play a major role in heterogeneous chemistry and photochemistry. In this dissertation research, transmission FTIR spectroscopy and X-ray photoelectron spectroscopy are used to probe the details of heterogeneous chemistry and photochemistry of CO2, SO2, NO2, HCOOH, and HNO3 on titanium dioxide and hematite surfaces. Adsorption sites, surface speciation and surface species stability have been determined from analysis of FTIR and XPS spectra. Isotope labeling experiments were also carried out in order to obtain mechanistic information about the details of surface hydroxyl group reactivity on these oxide particle surfaces. Furthermore, heterogeneous photochemical reactions of adsorbates from atmospheric trace gas adsorption on TiO2 and Α-Fe2O3 were investigated under the conditions pertinent to troposphere. The role of adsorbed water on the stability of adsorbed species that form as a result of heterogeneous reactions and the effect of relative humidity on photochemistry on these oxide particles surfaces has also been investigated due to its important implications in the atmospheric chemistry of oxide surfaces. The research adds to our overall scientific understanding of the molecular level details of heterogeneous chemistry and photochemistry of light absorbing components in the atmosphere.

The main aim of this thesis work is to investigate the electrical, optical and thermal impact characteristics of cobalt oxide doped antimony tin oxide (CoO-ATO) in the form of thin films and nanofiber membranes. CoO-ATO is a novel composite material that has the potential to be used as reinforced aircraft coatings, military garment coatings, or more specifically as an anti-reflective (AR) top coating for photovoltaic (PV) cells. This work will be critical in determining the effectiveness of using a CoO-ATO layer in these applications. Electrospun nanofibers and spin coated thin films consisting of a polymeric solution of CoO-ATO will be used. Thin films are created using spin coating techniques, and nanofiber membranes are created using an electrospinning technique. Polystyrene (PS) will be used as a solute, and chloroform as a solvent, to create the solution. It is hypothesized that coatings of this material will have improved optical characteristics as compared to traditional ATO coatings and minimum impact from thermal cycling making it a favorable candidate for PV cells. This work will do an electrical, optical and thermal cycling impact characterization of CoO-ATO thin films and nanofiber membranes for a doping range of x% CoO where x ranged from 0.2

A partir de la fin du 19ème siècle, des matériaux artificiels (le celluloïd, l'acétocellulose et la galalithe) sont mis au point et employés pour la fabrication d'objets de la vie quotidienne, en même temps que des matériaux naturels (nacre, bois, corne, écaille, ivoire et os), utilisés depuis toujours. Ces matériaux artificiels sont utilisés, dans un premier temps, pour imiter les matières naturelles, puis, dans un second temps, pour proposer d'autres formes et un choix de couleurs plus large. Aujourd'hui, l'enjeu est de mettre au point des méthodologies d'analyses afin de différencier et d'identifier ces matériaux qu'ils soient naturels ou artificiels. Les objets que nous avons analysés sont des éventails et des boutons, datés entre la fin du 19ème et le début du 20ème siècle, et conservés dans les collections du musée Galliera, à Paris. Les méthodologies d'analyse doivent être totalement non-destructives. Deux techniques d'analyses répondent à ce critère : la spectroscopie Raman et la spectroscopie infrarouge-ATR (Attenuated Total Reflexion). Les compositions chimiques de ces neuf matériaux étant extrêmement diversifiées, une unique méthodologie ne peut suffire à les identifier tous. Aussi, nous avons établi plusieurs stratégies d'identification, adaptées à chaque type de matériau. Les matériaux naturels, nacre et bois, sont identifiés par comparaison de leurs spectres Raman à des spectres de référence. Les matériaux artificiels, celluloïd et acétocellulose, sont aussi identifiés en spectroscopie Raman, par référence à leurs composants principaux. L'analyse spectrale des bandes amide I des spectres infrarouge-ATR de la corne, de l'écaille et de la galalithe a permis la détermination des structures secondaires de ces matériaux, conduisant à leur différenciation. Enfin, la différenciation des ivoires et des os nécessite l'application d'une analyse chimiométrique (analyse en composantes principales) de l'ensemble de leurs spectres infrarouge-ATR. Toutes ces stratégies d'identification ont été appliquées aux éventails et boutons du musée Galliera, et le matériau de chacun d'entre eux a été soit caractérisé, soit identifié. Ces identifications ont permis, entre autre, la mise en évidence de l'introduction précoce des matériaux artificiels dans la fabrication d'accessoires de mode (éventail de 1885 identifié en celluloïd).

Bacterial spores have remarkable resistance to a variety of harsh conditions, causing spoilage in food industry and becoming the primary bacterial agent in biowarfare and bioterrorism. In this study, inactivation mechanisms of Bacillus amyloliquefaciens (BA) spores by non-thermal plasma (NTP) were investigated by using Fourier-transform infrared spectroscopy (FTIR) as a major tool to exam spores after NTP treatment. Chemometric techniques, such as multivariate classification models based on soft independent modeling of Class Analogy (SIMCA) and Principal Component Analysis (PCA), were employed to identify functional group changes in FTIR spectra. The IR absorbance bands correlated to dipicolinic acid (DPA) decreased after NTP treatment indicating that DPA released and then reacted with reactive species generated by NTP and it was confirmed by nuclear magnetic resonance (NMR). Also IR absorbance bands corresponding to protein structure changed. FTIR combined with UV-Vis spectroscopy was used to monitor spore germination. Large amount of DPA released in a short time when spores germinated at 50°C, showing that DPA released in response to heating. NTP treated spores could germinate with little DPA release due to sub-lethal effects induced by plasma. Also an empirical model based on Weibull distribution was established to describe the spore germination process showing that NTP treated spores exhibited abnormal germination pattern. Inactivation mechanisms of NTP with air as feed gas was compared with high-pressure, wet heat, chemical treatment using chlorine dioxide (CD) and NTP with argon as feed gas. The results showed that few chemical changes in spores after autoclave and high pressure treatments, though protein structure changed. CD and NTP with air as feed gas inactivated spores by oxidation. DPA released after NTP with argon as feed gas treatment and it is possible that UV and charged particles accounts for the inactivation. This study provides in depth insight into the inactivation mechanism of NTP and information for optimizing NTP process.

Il lavoro affronta l'analisi funzionale dei contenitori ceramici provenienti da diversi contesti archeologici attraverso un approccio interdisciplinare. Le metodologie di analisi adottate affiancano all'approccio archeologico i risultati derivanti dall'integrazione con metodiche e strumenti di analisi di tipo archeometrico. Uno degli obiettivi principali della ricerca è quello di risalire alla funzione pratica dei contenitori ceramici attraverso l'analisi chimica dei residui organici in essi contenuti. È stato affrontato uno studio comparato di varie classi ceramiche, provenienti dai seguenti contesti in corso di scavo da parte dell'Università di Lecce: abitato arcaico di San Vito dei Normanni (Br), santuario di Tas Silg (Malta), santuario di Apollo a Hierapolis (Turchia). I materiali ceramici selezionati sono stati sottoposti ad analisi chimiche finalizzate ad identificare i residui organici, attraverso l'impiego incrociato di due tecniche analitiche: Gas cromatografia con spettrometria di massa (GC/MS) e Spettroscopia ad infrarossi in trasformata di Fourier (FTIR). I materiali sono stati inoltre letti in rapporto ai contesti di provenienza, al fine di pervenire anche ad una valutazione della distribuzione dei contenitori ceramici sulla superficie e quindi delle attività che si svolgevano nelle diverse aree di un ambiente o di un edificio, dei sistemi di immagazzinamento delle derrate, delle modalità di preparazione e di consumo del cibo. / In the framework of a study on the relations between form and function of pottery, organic residues analysis has been applied to different types of vessels from three archaeological sites excavated by the University of Lecce: San Vito dei Normanni (Brindisi, South Italy), Tas Silg sanctuary (Malta), Apollo sanctuary at Hierapolis (Turkey). Organic residues were identified by two analytical procedures based on gas chromatography coupled with mass spectrometry (GC-MS) and on Fourier transformed infrared spectroscopy (FTIR) respectively.

The research institute ETC in Piteå is working with energy technical research and development. Today, much work revolves around research about renewable sources for fuel. In one project, biomass such as wood pellet is heated up while producing synthesis gas. The synthesis gas is then analyzed using three different GC techniques. ETC wanted to be able to make all their analysis on one instrument and with a faster speed. They contacted the company Rowaco in Linköping for help with developing a method on FTIR for analysis of the synthesis gas and that has been the aim for this thesis. A method has been developed for analysis of water, carbon monoxide, carbon dioxide and methane. The results from this thesis show that the concentrations of the molecules in the synthesis gas are outside the calibration curved that has been made and that the high concentrations give much interference to other molecules. The thesis also shows that many areas in the spectrum from the process are roof absorbers and there is also a contamination of water and carbon dioxide in the system. Suggested improvements are to find the source for the contamination, to develop calibration points with higher concentrations, to reduce the length of the gas cell and to dilute the gas before entering the FTIR.