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Raman spectroscopy has been used to characterise both organic and geological samples in order to build a database for the future characterization of biomarker molecules that are of astrobiological relevance. Characteristic geological features and hydrated minerals recently found on the surface of Mars by the NASA planetary rovers Spirit and Opportunity suggest that a possible biosphere could have once existed there. Analytical instrumentation protocols for the unequivocal detection of biomarkers in suitable geological matrices are critical for future unmanned explorations, including the forthcoming ESA ExoMars mission scheduled for 2018. Several geological features found on the surface of Mars by planetary rovers suggest that a possible extinct biosphere could exist based on similar sources of energy as occurred on Earth. For this reason, analytical instrumental protocols for the detection of isolated biomarkers preserved in suitable geological matrices unequivocally and non-destructively have to be evaluated for future unmanned missions. Raman spectroscopy is currently part of the Pasteur instrumentation suite of the ExoMars mission for the remote detection of extant or extinct life signatures in the Martian surface and subsurface. Terrestrial analogues of Martian sites have been identified and the biogeological modifications resulting from extremophilic survival activity have been studied. Here we present the Raman spectral characterization of several examples of organic compounds which have been recorded using 785 nm, 633 nm and 514 nm laser excitation -polycyclic aromatic hydrocarbons (PAHs), organic acids, chlorophyll and carotenoids. Experimental mixtures of ß-carotene in usnic acid, PAHs in usnic acid and PAHs in mineral matrices have also been investigated. Organic compounds and PAHs located under crystalline minerals samples were identified using a 5x objective lens and 785 nm III excitation. The pure compounds and compound mixtures were also analysed using X-ray powder diffraction and scanning electron microscopy (SEM). The results of this study indicate that near infrared laser at 785 nm provided the clearest and the most informative spectra due to the reduction of fluorescence emission. Higher energy lasers operating in the visible region have resulted in the emission of significant background fluorescence. Few samples fluoresce even with the use of 785 nm excitation and FT-Raman spectroscopy remains the instrument of choice for the analysis of these samples.

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Raman spectroscopy has been used to characterise both organic and geological samples in order to build a database for the future characterization of biomarker molecules that are of astrobiological relevance. Characteristic geological features and hydrated minerals recently found on the surface of Mars by the NASA planetary rovers Spirit and Opportunity suggest that a possible biosphere could have once existed there. Analytical instrumentation protocols for the unequivocal detection of biomarkers in suitable geological matrices are critical for future unmanned explorations, including the forthcoming ESA ExoMars mission scheduled for 2018. Several geological features found on the surface of Mars by planetary rovers suggest that a possible extinct biosphere could exist based on similar sources of energy as occurred on Earth. For this reason, analytical instrumental protocols for the detection of isolated biomarkers preserved in suitable geological matrices unequivocally and non-destructively have to be evaluated for future unmanned missions. Raman spectroscopy is currently part of the Pasteur instrumentation suite of the ExoMars mission for the remote detection of extant or extinct life signatures in the Martian surface and subsurface. Terrestrial analogues of Martian sites have been identified and the biogeological modifications resulting from extremophilic survival activity have been studied. Here we present the Raman spectral characterization of several examples of organic compounds which have been recorded using 785 nm, 633 nm and 514 nm laser excitation -polycyclic aromatic hydrocarbons (PAHs), organic acids, chlorophyll and carotenoids. Experimental mixtures of ß-carotene in usnic acid, PAHs in usnic acid and PAHs in mineral matrices have also been investigated. Organic compounds and PAHs located under crystalline minerals samples were identified using a 5x objective lens and 785 nm III excitation. The pure compounds and compound mixtures were also analysed using X-ray powder diffraction and scanning electron microscopy (SEM). The results of this study indicate that near infrared laser at 785 nm provided the clearest and the most informative spectra due to the reduction of fluorescence emission. Higher energy lasers operating in the visible region have resulted in the emission of significant background fluorescence. Few samples fluoresce even with the use of 785 nm excitation and FT-Raman spectroscopy remains the instrument of choice for the analysis of these samples.

This study describes the technique and procedures used for the simultaneous determination of elements involved in Instrumental Neutron Activation Analysis, applied to some geological samples as a sensitive and non-destructive tool. Using Isotopic Neutron Source, the delayed gamma-rays emitted due to neutron capture have been applied for the investigation of the elemental constituents and concentrations of major, minor and trace elements in such samples. The experimental investigations were carried out at the scale of researcher's practices at the chosen site by measuring soil/rock nutrient contents from hydrologically isolated farmland/site plots. Using detailed sampling procedures with special precautions, against contaminations, to yield meaningful results, soil/rock samples have been collected from selected areas of East Gojjam, pulverized, homogenized and prepared for irradiation. The samples were properly prepared together with known standards of potassium iodide or cupric sulphate or arsenic trioxide (one /or both at a time), and simultaneously irradiated in to isotopic neutron ux in the same irradiation position. After activation, the samples were subjected to gamma-ray spectrometry, using a high-purity germanium detection system and computerized multichannel analyzer. The gamma-ray spectra from the irradiated samples were measured by high resolution gamma-ray spectrometry with a calibrated germanium detector. Both qualitative and quantitative approach to data collection and analysis were used in order to gain insight into what should be acceptable to the community. The results obtained have a practical interest in view of possible applications to the technology of extraction and exploration of a variety of industrial, metallic, cement minerals, and geothermal energy and coal deposits. These results tend to agree with the lowest values reported in the literature, and the analytical precision is su cient for the determination of the standard deviation of the distribution of all elements in East Gojjam and these results were brie y discussed within the text of this research work. In carrying out the analysis, the best and most convenient method being the Instrumental and /non-destructive Neutron Activation Analysis was adopted, and NAA has matured and attained analytical competence providing not only rapid, quantitative, qualitative, simultaneous, multi􀀀element analysis but also crucial validation support to programmes using di erent analytical techniques. This method of analysis is generally multi-element and experimental conditions can be designed to be non􀀀destructive to the sample, and it plays a leading role among analytical techniques in the eld of environmental research related to human, animal and plant health. Studies of di erent radionuclide and trace elements in the environmental samples are very important for health physics, research and education. Many forms of elements are possible in environmental samples which may be hazardous for human being, animals and also plants. Most of them have the potential for both benefcial and harmful effects / Environmental Sciences / D. Phil. (Environmental Science)

This study describes the technique and procedures used for the simultaneous determination of elements involved in Instrumental Neutron Activation Analysis, applied to some geological samples as a sensitive and non-destructive tool. Using Isotopic Neutron Source, the delayed gamma-rays emitted due to neutron capture have been applied for the investigation of the elemental constituents and concentrations of major, minor and trace elements in such samples. The experimental investigations were carried out at the scale of researcher's practices at the chosen site by measuring soil/rock nutrient contents from hydrologically isolated farmland/site plots. Using detailed sampling procedures with special precautions, against contaminations, to yield meaningful results, soil/rock samples have been collected from selected areas of East Gojjam, pulverized, homogenized and prepared for irradiation. The samples were properly prepared together with known standards of potassium iodide or cupric sulphate or arsenic trioxide (one /or both at a time), and simultaneously irradiated in to isotopic neutron ux in the same irradiation position. After activation, the samples were subjected to gamma-ray spectrometry, using a high-purity germanium detection system and computerized multichannel analyzer. The gamma-ray spectra from the irradiated samples were measured by high resolution gamma-ray spectrometry with a calibrated germanium detector. Both qualitative and quantitative approach to data collection and analysis were used in order to gain insight into what should be acceptable to the community. The results obtained have a practical interest in view of possible applications to the technology of extraction and exploration of a variety of industrial, metallic, cement minerals, and geothermal energy and coal deposits. These results tend to agree with the lowest values reported in the literature, and the analytical precision is su cient for the determination of the standard deviation of the distribution of all elements in East Gojjam and these results were brie y discussed within the text of this research work. In carrying out the analysis, the best and most convenient method being the Instrumental and /non-destructive Neutron Activation Analysis was adopted, and NAA has matured and attained analytical competence providing not only rapid, quantitative, qualitative, simultaneous, multi􀀀element analysis but also crucial validation support to programmes using di erent analytical techniques. This method of analysis is generally multi-element and experimental conditions can be designed to be non􀀀destructive to the sample, and it plays a leading role among analytical techniques in the eld of environmental research related to human, animal and plant health. Studies of di erent radionuclide and trace elements in the environmental samples are very important for health physics, research and education. Many forms of elements are possible in environmental samples which may be hazardous for human being, animals and also plants. Most of them have the potential for both benefcial and harmful effects / Environmental Sciences / D. Phil. (Environmental Science)

[pt] Os metais estão presentes em diversos materiais e muitos deles, como o níquel e o cromo, possuem papeis significativos em diversos setores industriais. A quantificação desses metais é importante tanto para obtenção de informações relevantes a respeito desses materiais, como para avaliação de possíveis contaminações ambientais. No presente trabalho, foram desenvolvidos métodos analíticos para a determinação de níquel e cromo em amostras de asfalto, brita e CAP por espectrometria de massa com plasma indutivamente acoplado usando calibração externa e diluição isotópica. Para a avaliação da exatidão dos métodos foram utilizados os materiais de referência certificados NIST 1084a e NBS 688. Como métodos de preparo de amostra, foram estudadas a decomposição ácida em bloco digestor, e a diluição em uma mistura de xileno/butanol na proporção 60:40 v:v (para amostras de óleo). Para a correção da interferência da espécie 40Ar12C positivo sobre o isótopo de 52Cr foi utilizada a célula de reação dinâmica com introdução de CH4 como gás de reação, o que reduziu de forma significativa o sinal de fundo característico para o isótopo de cromo. Os métodos desenvolvidos se mostraram eficientes na determinação dos metais. As recuperações obtidas para os SRMs se encontram entre 80-120 porcento. As concentrações médias, em mg kg-1 , encontradas para Ni pelos diferentes métodos nas amostras de CAP, brita e asfalto foram, respectivamente 39,9 mais ou menos 0,6, 6,7 mais ou menos 0,5 e 11,2 mais ou menos 0,8, enquanto para Cr as concentrações foram 1,8 mais ou menos 0,1, 15,3 mais ou menos 0,3, 16,6 mais ou menos 0,4. O sucesso da aplicação da diluição isotópica em amostras dissolvidas em solvente orgânico mostrou-se muito promissor, pois elimina a necessidade da decomposição ácida das matrizes tornando o preparo das amostras mais rápido e menos trabalhoso. / [en] Metals are present in several samples and many of them, such as nickel and chromium, have significant roles in several industry sectors. The quantification of these metals is important both for obtaining relevant information regarding these materials, and for evaluating possible environmental contaminations. In the present work, analytical methods were developed for the determination of nickel and chromium in asphalt, crushed stone and CAP samples by inductively coupled plasma mass spectrometry using both external calibration technique and isotopic dilution. To evaluate accuracy of the method, the certified reference materials NIST 1084a and NBS 688 were used. Two different methods of sample preparation were employed, block digestion and direct dilution in a xylene / butanol mixture using a 60:40 v:v ratio (for the oil samples). For the interference correction imposed by 40Ar12C over 52Cr, the dynamic reaction cell was used with CH4 as the reaction gas, which significantly reduced the characteristic background signal of the chromium isotope. The methods developed proved to be efficient in the determination of the metals in question. The recovery values obtained for the SRMs were between 80-120 percent. The average concentrations, in mg kg-1 , found for Ni by the different methods in CAP, crushed stone and asphalt samples were, respectively, 39,9 more or less 0,6, 6,7 more or less 0,5 and 11,2 more or less 0,8, while for Cr the concentrations were 1,8 more or less 0,1, 15,3 more or less 0,3, 16,6 more or less 0,4. The successful application of isotope dilution in samples dissolved in organic solvent is very promising because it eliminates the need for acid digestion, making the sample preparation faster and less labor intensive.

[pt] A distribuição de elementos de terras raras (REE) é representativa das rochas e solos que originalmente os contêm e é frequentemente usada como parâmetro geoquímico ou ambiental para identificação de fontes. Este trabalho propõe um novo método de preparo de amostras para a determinação de elementos de terras raras (REE) por espectrometria de massa de plasma acoplada indutivamente (ICPMS) em amostras ambientais com altas concentrações de Ba. O método consiste na diluição das amostras, obtidas após decomposição ácida em sistema aberto, com ácido sulfúrico 10 porcento (v/v) para a separação de Ba2positive como BaSO4. A remoção da interferência sobre os isótopos de Eu (151Eu and 153Eu) foi eficiente para concentrações de Ba superiores a 0,1 mg L-1. A exatidão e a precisão foram verificadas pela análise de tres materiais certificados, rocha basáltica (NIST 688), Geological Survey (Granite G-2) e sedimento marinho (MESS-3). A metodologia proposta foi aplicada ao pavimento asfáltico, à brita e ao material de referencia certificado. Adicionalmente, todas as amostras foram decompostas por fusão alcalina e as concentrações de elementos majoritários e Eu foram determinadas por espectrometria de emissão ótica de plasma acoplada indutivamente (ICP OES). Os resultados da Eu estavam de acordo com a metodologia proposta, e os limites de detecção (LOD) para REE variaram de 0,003 mg L-1 (Lu) a 0,010 mg L-1 (Gd). A distribuição de REE foi medida em sedimentos superficiais e amostras de testemunhos coletados na Baía de Sepetiba, entre junho e setembro de 2016. A faixa de concentração de SREE foi entre 25-496 mg kg-1. Esse monitoramento é importante para avaliar o impacto da urbanização e desenvolvimento rápido e não planejado de atividades antropogênicas, comuns em muitas áreas costeiras tropicais do Brasil. / [en] The distribution of rare earth elements (REE) is representative of the rocks and soils that originally contain them and it is often used as a geochemical or an environmental parameter for source identification. This thesis proposes a new method for the determination of rare earth elements (REE), by inductively coupled plasma mass spectrometry (ICP-MS), in challenging environmental samples with high Ba concentrations. The method consists in diluting the wet sample digests, obtained after acid decomposition in an open system, with 10 porcento (v/v) sulfuric acid for the separation of Ba2+ as BaSO4. The interference removal on both Eu isotopes (151Eu and 153Eu) was efficient for Ba concentrations higher than 0.1 mg L-1. Accuracy and precision were verified by analysis of two certified materials, NIST 688 Standard Reference Material of basalt rock, Geological Survey G-2 granite and marine sediment reference material (MESS-3) provided by the National Research Council in Canada (NRC) was used to evaluate the accuracy of the REE determination in marine sediments. The proposed methodology was applied to asphalt pavement and crushed stone. Additionally, for comparison, all samples were decomposed by fusion and major elements and Eu concentrations were determined by inductively coupled plasma optical emission spectrometry (ICP OES). The Eu results were in agreement with the proposed methodology, and limits of detection (LOD) for REE varied from 0.003 mg L-1 (Lu) to 0.010 mg L-1 (Gd). The distribution of REE was also measured in surface sediments and sediment core collected in Sepetiba Bay, between June and September of 2016. The range of SREE concentrations was established between 25-496 mg kg-1. This monitoring is important to evaluate the impact of the fast and unplanned urbanization and development of anthropogenic activities, common to many tropical coastal areas in Brazil.