L’objectif de ce travail de thèse a été de développer et de valider une méthode d’analyse quantitative du silicium liquide par la technique LIBS (Laser Induced Breakdown Spectroscopy). Pour cela, le dispositif utilisé consiste en une mesure intrusive sur la surface de bulles gazeuses, générées au cœur du métal fondu par soufflage d’un gaz inerte au travers d’un tube. Dans un premier temps, les conditions d’acquisition du signal ont été optimisées pour permettre la répétabilité et la reproductibilité du signal LIBS en dépit des fluctuations paramétriques induites par le bullage. Dans un second temps, les paramètres expérimentaux affectant les propriétés physiques des plasmas produits ont été évalués pour maximiser la sensibilité de la mesure et réduire les limites de détection. Les deux paramètres clefs qui ont été identifiés sont la densité de puissance apportées par l’impulsion laser et la nature du gaz de bullage : l’intensité du signal et donc le nombre d’émetteurs dans les plasmas sont favorisés par les hautes énergies laser et par une atmosphère d’argon plutôt que d’hélium. Le diagnostic spectroscopique des plasmas générés en fonction de ces paramètres a permis de montrer qu’ils n’ont pas d’effet significatif sur la température des électrons, des ions et des espèces neutres. L’augmentation de masse ablatée par le laser et la modification des conditions de relaxation du plasma par le milieu ambiant sont les mécanismes majoritaires à considérer. Finalement un modèle d’analyse quantitatif a été construit dans les conditions optimisées pour les impuretés B, Al, Fe, Cu et Ti du silicium. Il permet d’atteindre des limites de détection qui vont de quelques ppmw pour les éléments B, Fe et Al jusqu’à moins de 0,5 ppmw pour le Cu et le Ti. Les concentrations prédites par LIBS présentent un très bon accord avec celles déterminées par une méthode ex-situ conventionnelle, l’ICP-OES, avec des écarts relatifs inférieurs en moyenne à 10 %. Ceci démontre l’intérêt de la technique LIBS pour contrôler in-situ et en temps réel un procédé d’élaboration du silicium photovoltaïque. / The aim of this PhD research work was to develop and to validate a quantitative method to measure the composition of molten silicon by Laser Induced Breakdown Spectroscopy (LIBS). The device used consists in an intrusive measurement on the surface of gas bubbles which are produced by blowing an inert gas through a pipe inserted into the melt. First, the signal acquisition conditions were optimized to ensure LIBS signal repeatability and reproducibility to overcome experimental fluctuations due to the bubbling. Second, the experimental parameters affecting plasma physics were evaluated to maximize the measurement sensitivity and to lower the limits of detection. The two key parameters identified are the laser power density and the ambient gas: the signal intensity and then the number of emitters inside the plasma are promoted by higher laser energy and an Ar atmosphere rather than a He one. The plasma spectroscopic diagnosis as a function of these parameters showed that they don’t have significant effect on the temperature of electrons, ions and neutral species. The only mechanisms to be considered are then the increase of the mass ablated by the laser and the modification of the plasma relaxation conditions by the ambient atmosphere. Third, calibration curves were established for B, Al, Fe, Cu and Ti impurities under the optimized conditions. Limits of detections from few ppmw for B, Fe and Al to less than 0,5 ppmw for Ti and Cu have been achieved. The predicted concentrations by LIBS are in very good agreement with the ones measured by the conventional ex-situ method, ICP-OES. The mean relative discrepancy is lower than 10 %. These results demonstrate the LIBS benefits for in-situ and in-line monitoring of photovoltaic silicon production processes.

Orientador: Sizenando de Toledo Porto Neto / Banca: José Roberto Cury Saad / Banca: Victor Humberto Orbegoso Flores / Resumo: Atualmente, vários novos materiais estéticos são lançados no mercado odontológico destinados especificamente à confecção de restaurações diretas. Embora tais compósitos apresentem bons resultados clínicos, o que garantem ser indicados nas regiões anterior e posterior, ha a necessidade de comprovações adicionais para que se possam ser utilizados com segurança. As informações disponíveis de cada material recém introduzido ainda trazem duvidas sobre sua real composição e sobre suas propriedades físicas e mecânicas, gerando confusão para o clinico, que pode estar ciente ou não de qual resina melhor atende as necessidades de cada paciente. O conhecimento dimensional do conteúdo inorgânico dos sistemas de resinas compostas ainda e o responsável pela classificação dos mesmos e parecem estimar sobre suas propriedades mecânicas. Assim, nos propusemos a (1) estudar através de ampla e profunda revisão sistemática da literatura, a influencia das partículas inorgânicas nas propriedades físicas, químicas e mecânicas de resinas compostas e; (2) descrever a morfologia e a composição química das partículas inorgânica das resinas compostas atuais, como forma de dotar o clinico de um parâmetro de comparação entre os materiais restauradores resinosos, e de auxiliá-lo na indicação deste material mediante situação clínica. Na primeira etapa de nosso estudo, foram determinados os critérios de inclusão e exclusão, e estabelecida a estratégia de busca - palavras-chave e limites de assuntos, em varias combinações - dos estudos laboratoriais nas principais bases de dados eletrônicas (ISI - Web of Science, Medline, Biblioteca Cochrane, SciELo, Lilacs e Biblioteca Digital de Teses - Portal Capes), e outras fontes de informação. / Abstract: Currently, dozens of new aesthetic materials are launched on the dentistry market designed specifically to the confection of direct restorations. Although such composite show good clinical results, which guarantees be given in anterior and posterior regions, there is a need for additional evidence so that it can be used safely. The information available of each newly introduced material also brings questions about their real composition and on its physical and mechanical properties, creating confusion for the clinician, which may be or not aware of resin which best meets the necessities of each patient. The dimensional knowledge of the inorganic content of the composed resin systems also is responsible for the classification of the same ones and seems estimate on its mechanical properties. Thus, we proposed (1) to study through extensive and meticulous systematic review of literature, the influence of inorganic particles in the physical, chemical and mechanical properties of composite resins and; (2) to describe the morphology and chemical composition of the inorganic particles of current composite resins, as a way of giving the clinician with a parameter of comparison among the resinous restorative materials, and of assisting it in the indication of this material through of clinical situation. In the first stage of our study, the criteria of inclusion and exclusion had been determined, and established the strategy of search - keywords and limits of subjects, in some combinations - of the laboratory studies in the main electronic databases ((ISI - Web of Science, Medline, Biblioteca Cochrane, SciELo, Lilacs and Digital Library of Theses - Portal Capes), and others sources of information. Of the 138 abstracts located, only 59 were selected (most located on Pubmed) being in accordance with the pre-established criteria. / Mestre

Multielement analysis of flue gas residues from secondary lead smelting was tested using seven decomposition methods on four different flue gas residues and certified reference materials (CRM) CPB-2 (Pb concentrate, CCRMP). The studied samples contained both silicates and also high contents of phases with Pb, primarily Pb chlorides and sulphates. Solutions prepared by various decomposition methods were analysed using ICP OES (Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Si, Sn, Sr, Ti, Tl, V, Zn). Greater yields were found for most of the elements by combined decomposition (with fusion) and decomposition by sintering. Nonetheless, both methods exhibited major losses of volatile elements (As, Bi, Sb, Tl). Thus, one of these methods must always be combined with a method of decomposition in a closed system. The work also demonstrates that, for investigation of untraditional waste geological materials (e.g. flue residues from high- temperature industrial processes), it will be necessary in the future to produce new certified reference materials with anomalous chemical and mineralogical compositions, which are not currently available on the market. Laboratory extraction tests were performed on two different types of flue residues - kinetic (30 days) with ratio L/S...

Study of plasma in the mixtures with molecular gas at wide pressure range Matěj Jan Morávek Abstract: The positive column of DC glow discharge sustained in oxygen and oxygen-nitrogen mixtures has been studied in two discharge tubes of the same shape made from different materials (Silica and Pyrex glass) for total pressures 650 - 2000 Pa and discharge currents up to 40 mA. Various parameters of the discharge - axial electric field strength, concentration of electrons and emission spectra - were studied with emphasis placed on transition region between low- and high-gradient form of the positive column. We have focused on the qualitative and quantitative analysis of the differences in emission spectra for both particular forms and the transitional region between them. The impact of 1 % admixture of nitrogen was also studied.

O objetivo deste trabalho foi o desenvolvimento de metodologia analítica versátil e rápida para a determinação de Cr, Mn e Ni em aços martensíticos e austeníticos, através do processo de dissolução química parcial em sistema de injeção em fluxo acoplado ao Espectrômetro de Emissão Ótica acoplado indutivamente (ICP-OES). O procedimento, também priorizou menor manipulação de amostra e consumo de reagentes. A solução extratora, HNO3 e HCI 7,0 mol L-1 e 6,0 mol L-1 respectivamente 1:1 v/v foi utilizada para a dissolução química parcial dos aços inoxidáveis. A quantificação dos metais dissolvidos foi feita utilizando-se o método da somatória, que relaciona a concentração de um elemento individual com a somatória dos elementos determinados, segundo a fórmula: i% = Ci /Ct x 100, onde Ci é a concentração do elemento i e Ct é a soma das concentrações de todos elementos determinados. Os resultados não apresentaram diferença significativa em um nível de confiança de 95% com os valores certificados das amostras de referência e com os valores da dissolução total assistida por microondas. O procedimento apresentou freqüência analítica de 20 determinações por hora. / The objective of this work was the development of a versatile and fast analytical methodology for the determination of Cr, Mn, and Ni in martensitic and austenitic steels, through on-line partial chemical dissolution using a flow injection system coupled to an ICP-OES. The procedure also aimed the smallest sample manipulation and reagents consumption. The extractor solution, 7.0 mol L-1 HNO3 and 6.0 mol L-1 HCI 1:1 v/v, was used to the on-line partial chemical dissolution of the stainless steels. The quantification of the dissolved metals was made using a method, that relate the concentration of an individual element with the sum of all elements concentrations, applying the formula: i% = Ci /Ct x 100, where Ci is the concentration of the element i and Ct is the sum of the concentration of all elements determined. No significant difference has been present by the results, at a confidence level of 95%, with the certified values of the reference materials and with the total dissolution values obtained by microwave - assisted sample pretreatment. The procedure presented analytic frequency of 20 determinations per hour.

O objetivo deste estudo foi avaliar parâmetros para o desenvolvimento de métodos visando à determinação elementar em alumina, cimento e quartzo por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) com amostragem de suspensão. Alguns elementos foram investigados como possíveis candidatos a padrões internos (PIs) Be, Dy, Gd, In, La, Sc, Y, Yb eTl. Amostras de material de referência certificado (CRM) de alumina (Alumina Reduction Grade 699), de cimento Portland (1889a Blended with Limestone e 1886a White Portland cement with low iron) do National Institute of Standard and Technology (NIST), e amostras de quartzo, cedidos pelo Departamento de Física da Universidade Federal de São Carlos (UFSCar), denominados T-4FI, T-2FI e T-4GR, foram utilizadas na otimização instrumental, no desenvolvimento e na avaliação da exatidão do método. Nanopartículas de sílica de alta pureza (Wacker HDK® T40), Wacker Chemie AG foram utilizadas no estudo de adsorção dos elementos e padrões internos como proposta de produção de material calibrante para a análise direta de sólidos. Para a escolha dos PIs foram construídos gráficos de correlação usando valores de potenciais de excitação, energias de ionização e temperaturas de fusão dos analitos e dos candidatos a PIs. Análise exploratória por agrupamentos hierárquicos (HCA) e análise dos componentes principais (PCA), também foram realizadas. A avaliação de desempenho do ICP OES foi feita em meio das suspensões das amostras a partir do estabelecimento de figuras de mérito como sensibilidade, robustez, seletividade e repetibilidade. Na otimização do foram considerados os parâmetros potência, vazão de nebulização e vazão de gás auxiliar. A determinação de Ca, Fe, Ga, Na, Si e Zn em alumina foi feita após dissolução em forno de micro-ondas com posterior precipitação do Al(III) com NH3. O uso de padrão interno foi essencial para a exatidão do método, com recuperações do CRM que variaram de 83 a 117%. Para a matriz cimento foram avaliados o efeito da concentração de ácido nítrico na extração dos analitos ( Al, Ca, Cr, Fe, K, Mg, Mn, Na, P, S, Si, Sr, Ti e Zn) e na adsorção dos elementos candidatos a PIs (Be, Sc, In, Dy). As determinações por suspensão e uso de padrão interno (exceto para Cr, S e Zn), com 0,5% v v-1 de HNO3, nebulizador Burgener e condições robustas do ICP geraram resultados com recuperações entre 68 e 119%. As determinações de Al, Ba, Cr, Fe, K, Li, Mg, Na, Sr e Ti em quartzo foram executadas com introdução de suspensão e ausência de padrão interno, usando condições do ICP similares àquelas adotadas na determinação elementar para matriz de cimento. Nesse caso as recuperações variaram de 90 a 107%. A adsorção dos analitos e padrões internos sobre as nanopartículas de sílica pode ser uma alternativa para a preparação de padrões de calibração quando se deseja realizar a introdução direta do material sólido em suspensão. / The aim of this study was to evaluate parameters for the development of methods for elements determination in alumina, cement and quartz by inductively coupled plasma optical emission spectrometry (ICP OES) with slurry sampling. Some elements were investigated as candidates for internal standards (ISs) Be, Dy, Gd, In, La, Sc, Y, Yb and Tl. Samples of certified reference material (CRM) of alumina (Alumina Reduction Grade - 699), Portland cement (blended with the 1889a and 1886a Limestone White Portland cement with low iron) from the National Institute of Standards and Technology (NIST), and quartz samples, suplied by the Department of Physics from Federal University of São Carlos (UFSCar), named T-4FI, T-2FI and T4GR were used to optimize instrumental, method development and accuracy evaluation of the method. Nanoparticles of high purity silica (Wacker HDK T40 ®), Wacker Chemie AG were used in the study adsorption of the analytes and internal standards as calibrating material for direct analysis of solids. Correlation graphs using excitation potentials, ionization energies and melting point temperatures were used for chosing the best ISs. Exploratory analysis using hierarchical cluster analysis (HCA) and principal component analysis (PCA) were also performed. Optimization of ICP OES was performed in aqueous and slurry samples to establishment figures of merit, such as sensitivity, robustness, selectivity and repeatability. In the optimization of ICP, power supply, nebulizer flow rate and auxiliary gas flow rate were considered. The determination of Ca, Fe, Ga, In, Si and Zn in alumina was made after decomposition in a microwave oven with subsequent precipitation of Al(III) with NH3 gas. The internal standard was essential to obtain the accuracy of the method, with recoveries of CRM analysis ranging from 83 to 117%. For the cement analysis was evaluated the effect of nitric acid concentration over analytes extraction (Al, Ca, Cr, Fe, K, Mg, Mn, Na, P, S, Si, Sr, Ti and Zn) and ISs candidate adsorption (Be, Sc, In and Dy). Determinations of the elements in cement slurry with the internal standard (except for Cr and Zn), with 0.5% v v-1 HNO3, nebulizer Burgener and robust conditions of ICP produced results with recoveries between 68 and 119%. The determinations of Al, Ba, Cr, Fe, K, Li, Mg, Na, Sr and Ti in quartz were performed with the slurry introduction and without of internal standard, using similar conditions of those adopted for cement matrix. In this case the recoveries ranged from 90 to 107% with addition and recovery test. The adsorption of the analytes and internal standards on silica nanoparticles could be an alternative for the preparation of calibration standards when considering performing the direct introduction of solid material.

O objetivo deste estudo foi avaliar parâmetros para o desenvolvimento de métodos visando à determinação elementar em alumina, cimento e quartzo por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) com amostragem de suspensão. Alguns elementos foram investigados como possíveis candidatos a padrões internos (PIs) Be, Dy, Gd, In, La, Sc, Y, Yb eTl. Amostras de material de referência certificado (CRM) de alumina (Alumina Reduction Grade 699), de cimento Portland (1889a Blended with Limestone e 1886a White Portland cement with low iron) do National Institute of Standard and Technology (NIST), e amostras de quartzo, cedidos pelo Departamento de Física da Universidade Federal de São Carlos (UFSCar), denominados T-4FI, T-2FI e T-4GR, foram utilizadas na otimização instrumental, no desenvolvimento e na avaliação da exatidão do método. Nanopartículas de sílica de alta pureza (Wacker HDK® T40), Wacker Chemie AG foram utilizadas no estudo de adsorção dos elementos e padrões internos como proposta de produção de material calibrante para a análise direta de sólidos. Para a escolha dos PIs foram construídos gráficos de correlação usando valores de potenciais de excitação, energias de ionização e temperaturas de fusão dos analitos e dos candidatos a PIs. Análise exploratória por agrupamentos hierárquicos (HCA) e análise dos componentes principais (PCA), também foram realizadas. A avaliação de desempenho do ICP OES foi feita em meio das suspensões das amostras a partir do estabelecimento de figuras de mérito como sensibilidade, robustez, seletividade e repetibilidade. Na otimização do foram considerados os parâmetros potência, vazão de nebulização e vazão de gás auxiliar. A determinação de Ca, Fe, Ga, Na, Si e Zn em alumina foi feita após dissolução em forno de micro-ondas com posterior precipitação do Al(III) com NH3. O uso de padrão interno foi essencial para a exatidão do método, com recuperações do CRM que variaram de 83 a 117%. Para a matriz cimento foram avaliados o efeito da concentração de ácido nítrico na extração dos analitos ( Al, Ca, Cr, Fe, K, Mg, Mn, Na, P, S, Si, Sr, Ti e Zn) e na adsorção dos elementos candidatos a PIs (Be, Sc, In, Dy). As determinações por suspensão e uso de padrão interno (exceto para Cr, S e Zn), com 0,5% v v-1 de HNO3, nebulizador Burgener e condições robustas do ICP geraram resultados com recuperações entre 68 e 119%. As determinações de Al, Ba, Cr, Fe, K, Li, Mg, Na, Sr e Ti em quartzo foram executadas com introdução de suspensão e ausência de padrão interno, usando condições do ICP similares àquelas adotadas na determinação elementar para matriz de cimento. Nesse caso as recuperações variaram de 90 a 107%. A adsorção dos analitos e padrões internos sobre as nanopartículas de sílica pode ser uma alternativa para a preparação de padrões de calibração quando se deseja realizar a introdução direta do material sólido em suspensão. / The aim of this study was to evaluate parameters for the development of methods for elements determination in alumina, cement and quartz by inductively coupled plasma optical emission spectrometry (ICP OES) with slurry sampling. Some elements were investigated as candidates for internal standards (ISs) Be, Dy, Gd, In, La, Sc, Y, Yb and Tl. Samples of certified reference material (CRM) of alumina (Alumina Reduction Grade - 699), Portland cement (blended with the 1889a and 1886a Limestone White Portland cement with low iron) from the National Institute of Standards and Technology (NIST), and quartz samples, suplied by the Department of Physics from Federal University of São Carlos (UFSCar), named T-4FI, T-2FI and T4GR were used to optimize instrumental, method development and accuracy evaluation of the method. Nanoparticles of high purity silica (Wacker HDK T40 ®), Wacker Chemie AG were used in the study adsorption of the analytes and internal standards as calibrating material for direct analysis of solids. Correlation graphs using excitation potentials, ionization energies and melting point temperatures were used for chosing the best ISs. Exploratory analysis using hierarchical cluster analysis (HCA) and principal component analysis (PCA) were also performed. Optimization of ICP OES was performed in aqueous and slurry samples to establishment figures of merit, such as sensitivity, robustness, selectivity and repeatability. In the optimization of ICP, power supply, nebulizer flow rate and auxiliary gas flow rate were considered. The determination of Ca, Fe, Ga, In, Si and Zn in alumina was made after decomposition in a microwave oven with subsequent precipitation of Al(III) with NH3 gas. The internal standard was essential to obtain the accuracy of the method, with recoveries of CRM analysis ranging from 83 to 117%. For the cement analysis was evaluated the effect of nitric acid concentration over analytes extraction (Al, Ca, Cr, Fe, K, Mg, Mn, Na, P, S, Si, Sr, Ti and Zn) and ISs candidate adsorption (Be, Sc, In and Dy). Determinations of the elements in cement slurry with the internal standard (except for Cr and Zn), with 0.5% v v-1 HNO3, nebulizer Burgener and robust conditions of ICP produced results with recoveries between 68 and 119%. The determinations of Al, Ba, Cr, Fe, K, Li, Mg, Na, Sr and Ti in quartz were performed with the slurry introduction and without of internal standard, using similar conditions of those adopted for cement matrix. In this case the recoveries ranged from 90 to 107% with addition and recovery test. The adsorption of the analytes and internal standards on silica nanoparticles could be an alternative for the preparation of calibration standards when considering performing the direct introduction of solid material.

Parmi les systèmes dédiés à l’analyse directe des solides, la vaporisation électrothermique occupe une place de choix. Elle offre plusieurs avantages. Le temps de préparation des échantillons est considérablement réduit. Il n’y a pas de dilution induite par la minéralisation et les risques de pertes ou de contaminations durant cette étape sont éliminés. Son principe de fonctionnement consiste à transformer, par chauffage, quelques milligrammes d’échantillon en un aérosol, qui est ensuite transporté dans un spectromètre d’émission atomique par plasma à couplage inductif, où la composition élémentaire est mesurée. Une première étude fondamentale a permis de mieux comprendre la dynamique de l’aérosol formé et de définir les meilleures conditions opératoires. L’utilisation de cette technique pour la détermination élémentaire dans les végétaux a présenté cependant des difficultés supplémentaires : difficulté d’étalonnage, effets de matrice et grandes variabilités sur les concentrations mesurées. L’utilisation d’un support de cellulose pour les solutions étalons a permis d’harmoniser les conditions de formation de l’aérosol pour l’échantillon et pour l’étalon, et d’obtenir ainsi des résultats justes. Les effets de matrices ont pu être considérablement réduits par une calcination préalable des échantillons. Le manque de précision des mesures, causée par le manque d’homogénéité des échantillons, a pu être limitée en de réduisant significativement la taille des particules solides. Ces résultats obtenus sur des poudres ont permis d’autres applications comme l’analyse d’échantillons entiers ou la cartographie de la composition chimique d’organes végétaux. / Among the systems dedicated to the direct analysis of the solids, electrothermal vaporization takes up a place of choice. It offers several advantages. The preparation time of the samples is considerably reduced. There is no dilution induced by the digestion and the risks of losses or contaminations during this stage are eliminated. Its functioning consists to convert, by heating, a few milligrams of sample into an aerosol which is then transported in an inductively coupled plasma atomic emission spectrometer, where the elemental composition of the sample is determinate. A first fundamental study allowed to better understand the dynamics of the formed aerosol and to define the best operating conditions. However, the use of this technique to determine the elemental composition of solid plant samples presented additional difficulties: difficulty of calibration, matrix effects and important imprecision on the measured concentrations. The use of a cellulose support for the standard solutions allowed to harmonize the formation of the aerosol between the sample and the standard, and to obtain accurate results. The matrix effects can be considerably reduced by a preliminary dry-ashing of the samples. The variability of measurements, caused by the lack of homogeneity of the samples, was limited by reducing significantly the size of the solid particles. These results, obtained on powders, allowed other applications as the analysis of whole plant samples or the imaging of the chemical composition of plant organs.

Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2017-08-30T14:53:20Z No. of bitstreams: 2 Ana Julia Penteado.pdf: 1485037 bytes, checksum: 723d1b3bedb90392ef459d2a4cedeca8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-30T14:53:20Z (GMT). No. of bitstreams: 2 Ana Julia Penteado.pdf: 1485037 bytes, checksum: 723d1b3bedb90392ef459d2a4cedeca8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Lithium carbonate is the main drug used to treat bipolar disorder. This medicine has a narrow therapeutic range and is usually used in a chronic way by the patients, generating the need for therapeutic monitoring by means of plasma lithium quantification. In addition, records of toxic effects from chronic medical use reinforce the need for a tool that assists in the treatment. Thus, a reliable methodology for the quantification of lithium and a therapeutic adjuvant emerge as a means to improve the quality of life of the patient. In our work, we used the flame atomic absorption spectrometer to validate the method for quantification of lithium and the results were satisfactory, because they complied with the required criteria, assuring the reliability of the method. In order to find a therapeutic adjuvant, N-acetylcysteine (NAC) was studied for presenting important characteristics against the toxic effects caused by lithium. In our results lithium presented toxic effects mainly inducing oxidative stress, while the coadministration of NAC reversed this effect in the liver, kidney and brain organs. The use of NAC as a therapeutic adjuvant has been shown to be promising, however, further studies need to be performed to better understand this relationship. / O carbonato de lítio é o principal medicamento utilizado no tratamento do transtorno bipolar. Este medicamento possuí estreita faixa terapêutica e geralmente é utilizado de forma crônica pelos pacientes, gerando a necessidade da monitorização terapêutica por meio da quantificação plasmática de lítio. Além disso, os registros de efeitos tóxicos decorrentes do uso medicinal crônico remetem a necessidade de uma ferramenta que auxilie no tratamento. Desta forma, uma metodologia confiável para a quantificação de lítio e um adjuvante terapêutico surgem como meios de melhorar a qualidade de vida do paciente. Em nosso trabalho, utilizamos o espectrômetro de absorção atômica de chama para validar um método para quantificação de lítio e os resultados foram satisfatórios, pois cumpriram os critérios exigidos, assegurando a confiabilidade do método. Com foco em buscar um adjuvante terapêutico, a N-acetilcisteína (NAC) foi estudada por apresentar características importantes contra os efeitos tóxicos causados pelo lítio. Em nossos resultados o lítio apresentou efeitos tóxicos principalmente induzindo o estresse oxidativo, enquanto que a coadministração de NAC reverteu esse efeito nos órgãos fígado, rim e cérebro. O uso da NAC como adjuvante terapêutico mostrou ser promissor, porém, mais estudos precisam ser realizados para entender melhor essa relação.

Obsidian has been a center of interest both for geologists and archaeologists. Geologists have studied on physical and chemical properties of obsidian where archaeologists have worked on this material as a common artifact found in excavations. In this study, obsidian samples from &Ccedil / atalh&ouml / y&uuml / k excavations are examined using their rare earth element (REE) concentrations. Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) have been used for this purpose. A mixture (4:1) of lithium metaborate and lithium tetraborate was used for fusion of samples. Because of the low concentrations of REEs, a preconcentration step is needed. Successful recovery results have been achieved with Amberlite IR-120. The developed method is tested using the standard reference material SARM-1.