In this dissertation research, two fundamental studies involving gas chromatography mass spectrometry of n-butylbenzene and pyrolysis products are presented. In the first study, fragmentation pathways of n-butylbenzene in quadrupole ion trap have been investigated. At low energy, product ion corresponding to m/z 92 and m/z 91 are formed via competitive parallel dissociation. Studies have also shown that at higher energy m/z 92 has sufficient internal energy to undergo further fragmentation yielding m/z 91 via consecutive dissociation. Thus in order to discern the fragmentation pathways of n-butylbenzene, the technique of two-dimensional correlation spectroscopy (2DCOS) was applied to the mass spectral data. Application of 2DCOS resulted in two 2D correlation spectra namely synchronous and asynchronous. A third spectra known as coherence spectra was obtained from the ration of asynchronous to synchronous correlation intensities. For the elucidation of n-butylbenzene fragmentation pathways, all the three spectra were utilized in this study. The second study in this dissertation involves investigation of pyrolysis products to aid in fire debris analysis. One of the major concerns in fire debris analysis is that pyrolysis products can mask the patterns of compounds of interest and make the chromatographic results interpretation extremely difficult. One of the approaches for investigating the formation of pyrolysis products is to subject the commonly found building materials to controlled heating in laboratory. In this study, new heating methodologies for controlled heating of substrates involving furnace, paint-cans and flat steel pans have been developed. The substrates used for investigating pyrolysis products were polystyrene, polyvinylchloride, polybutadiene, yellow-pine, nylon carpet and padding. Experiments were also performed to investigate the influence of hydrocarbons on the formation of pyrolysis.

The fate and behaviour of hydrophobic organic compounds (e.g. pesticides) in soils are largely controlled by sorption processes. Recent findings suggest that the chemical properties of soil organic carbon (OC) significantly control the extent of sorption of such compounds in soil systems. However, currently there is no practical tool to integrate the effects of OC chemistry into sorption predictions. Therefore, the K [subscript]oc model, which relies on the soil OC content (foc), is used for predicting soil sorption coefficients (K[subscript]d) of pesticides. The K[subscript]oc model can be expressed as K[subscript]d = K[subscript]oc × foc, where K[subscript]oc is the OC-normalized sorption coefficient for the compound. Hence, there is a need for a prediction tool that can effectively capture the role of both the chemical structural variation of OC as well as foc in the prediction approach. Infrared (IR) spectroscopy offers a potential alternative to the K[subscript]oc approach because IR spectra contain information on the amount and nature of both organic and mineral soil components. The potential of mid-infrared (MIR) spectroscopy for predicting K[subscript]d values of a moderately hydrophobic pesticide, diuron, was investigated. A calibration set of 101 surface soils from South Australia was characterized for reference sorption data (K[subscript]d and K[subscript]oc) and foc as well as IR spectra. Partial least squares (PLS) regression was employed to harness the apparent complexity of IR spectra by reducing the dimensionality of the data. The MIR-PLS model was developed and validated by dividing the initial data set into corresponding calibration and validation sets. The developed model showed promising performance in predicting K[subscript]d values for diuron and proved to be a more efficacious than the K[subscript]oc model. The significant statistical superiority of the MIR-PLS model over the K[subscript]oc model was caused by some calcareous soils which were outliers for the K[subscript]oc model. Apart from these samples, the performance of the two compared models was essentially similar. The existence of carbonate peaks in the MIR-PLS loadings of the MIR based model suggested that carbonate minerals may interfere or affect the sorption. This requires further investigation. Some other concurrent studies suggested excellent quality of prediction of soil properties by NIR spectroscopy when applied to homogenous samples. Next, therefore, the performance of visible near-infrared (VNIR) and MIR spectroscopy was thoroughly compared for predicting both foc and diuron K[subscript]d values in soils. Some eleven calcareous soils were added to the initial calibration set for an attempt to further investigate the effect of carbonate minerals on sorption. MIR spectroscopy was clearly a more accurate predictor of foc and K[subscript]d in soils than VNIR spectroscopy. Close inspection of spectra showed that MIR spectra contain more relevant and straightforward information regarding the chemistry of OC and minerals than VNIR and thus useful in modelling sorption and OC content. Moreover, MIR spectroscopy provided a better (though still not great) estimation of sorption in calcareous soils than either VNIR spectroscopy or the K[subscript]oc model. Separate research is recommended to fully explore the unusual sorption behaviour of diuron in calcareous soils. In the last experiment, two dimensional (2D) nuclear magnetic resonance/infrared heterospectral correlation analyses revealed that MIR spectra contain specific and clear signals related to most of the major NMR-derived carbon types whereas NIR spectra contain only a few broad and overlapped peaks weakly associated with aliphatic carbons. 2D heterospectral correlation analysis facilitated accurate band assignments in the MIR and NIR spectra to the NMR-derived carbon types in isolated SOM. In conclusion, the greatest advantage of the MIR-PLS model is the direct estimation of Kd based on integrated properties of organic and mineral components. In addition, MIR spectroscopy is being used increasingly in predicting various soil properties including foc, and therefore, its simultaneous use for K[subscript]d estimation is a resource-effective and attractive practice. Moreover, it has the advantage of being fast and inexpensive with a high repeatability, and unlike the K[subscript]oc approach, MIR-PLS shows a better potential for extrapolating applications in data-poor regions. Where available, MIR spectroscopy is highly recommended over NIR spectroscopy. 2D correlation spectroscopy showed promising potential for providing rich insight and clarification into the thorough study of soil IR spectra. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1415416 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

The fate and behaviour of hydrophobic organic compounds (e.g. pesticides) in soils are largely controlled by sorption processes. Recent findings suggest that the chemical properties of soil organic carbon (OC) significantly control the extent of sorption of such compounds in soil systems. However, currently there is no practical tool to integrate the effects of OC chemistry into sorption predictions. Therefore, the K [subscript]oc model, which relies on the soil OC content (foc), is used for predicting soil sorption coefficients (K[subscript]d) of pesticides. The K[subscript]oc model can be expressed as K[subscript]d = K[subscript]oc × foc, where K[subscript]oc is the OC-normalized sorption coefficient for the compound. Hence, there is a need for a prediction tool that can effectively capture the role of both the chemical structural variation of OC as well as foc in the prediction approach. Infrared (IR) spectroscopy offers a potential alternative to the K[subscript]oc approach because IR spectra contain information on the amount and nature of both organic and mineral soil components. The potential of mid-infrared (MIR) spectroscopy for predicting K[subscript]d values of a moderately hydrophobic pesticide, diuron, was investigated. A calibration set of 101 surface soils from South Australia was characterized for reference sorption data (K[subscript]d and K[subscript]oc) and foc as well as IR spectra. Partial least squares (PLS) regression was employed to harness the apparent complexity of IR spectra by reducing the dimensionality of the data. The MIR-PLS model was developed and validated by dividing the initial data set into corresponding calibration and validation sets. The developed model showed promising performance in predicting K[subscript]d values for diuron and proved to be a more efficacious than the K[subscript]oc model. The significant statistical superiority of the MIR-PLS model over the K[subscript]oc model was caused by some calcareous soils which were outliers for the K[subscript]oc model. Apart from these samples, the performance of the two compared models was essentially similar. The existence of carbonate peaks in the MIR-PLS loadings of the MIR based model suggested that carbonate minerals may interfere or affect the sorption. This requires further investigation. Some other concurrent studies suggested excellent quality of prediction of soil properties by NIR spectroscopy when applied to homogenous samples. Next, therefore, the performance of visible near-infrared (VNIR) and MIR spectroscopy was thoroughly compared for predicting both foc and diuron K[subscript]d values in soils. Some eleven calcareous soils were added to the initial calibration set for an attempt to further investigate the effect of carbonate minerals on sorption. MIR spectroscopy was clearly a more accurate predictor of foc and K[subscript]d in soils than VNIR spectroscopy. Close inspection of spectra showed that MIR spectra contain more relevant and straightforward information regarding the chemistry of OC and minerals than VNIR and thus useful in modelling sorption and OC content. Moreover, MIR spectroscopy provided a better (though still not great) estimation of sorption in calcareous soils than either VNIR spectroscopy or the K[subscript]oc model. Separate research is recommended to fully explore the unusual sorption behaviour of diuron in calcareous soils. In the last experiment, two dimensional (2D) nuclear magnetic resonance/infrared heterospectral correlation analyses revealed that MIR spectra contain specific and clear signals related to most of the major NMR-derived carbon types whereas NIR spectra contain only a few broad and overlapped peaks weakly associated with aliphatic carbons. 2D heterospectral correlation analysis facilitated accurate band assignments in the MIR and NIR spectra to the NMR-derived carbon types in isolated SOM. In conclusion, the greatest advantage of the MIR-PLS model is the direct estimation of Kd based on integrated properties of organic and mineral components. In addition, MIR spectroscopy is being used increasingly in predicting various soil properties including foc, and therefore, its simultaneous use for K[subscript]d estimation is a resource-effective and attractive practice. Moreover, it has the advantage of being fast and inexpensive with a high repeatability, and unlike the K[subscript]oc approach, MIR-PLS shows a better potential for extrapolating applications in data-poor regions. Where available, MIR spectroscopy is highly recommended over NIR spectroscopy. 2D correlation spectroscopy showed promising potential for providing rich insight and clarification into the thorough study of soil IR spectra. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1415416 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

Orientador: Marinônio Lopes Cornélio / Banca: Antônio José da Costa Filho / Banca: André Luiz Galo / Resumo: Esse trabalho tem por objetivo estudar as transições conformacionais, induzidas termicamente, na Ribonuclease A. Esta abordagem foi realizada aplicando!se a técnica de calorimetria diferencial de varredura (DSC) e infravermelho médio com transformada de Fourier (FTIR), associando a técnica de análise de correlação bidimensional (2D! COS), variável!variável (VV) e sample sample (SS). A partir dos dados de DSC determinamos a variação de entalpia do sistema (∆Hcal) que foi de 587 kJ/mol. Também identificamos as temperaturas de pré (36, 39, 43, 49 e 59°C), pós transição (71°C) e temperatura de melting (65°C), além da determinação do ∆Hcal para cada uma das transições. A análise de correlação bidimensional sample!sample (SS) também foi capaz de identificar as mesmas temperaturas encontradas por DSC. Por sua vez, a análise de correlação bidimensional variável!variável (VV) descreveu a evolução conformacional das estruturas secundárias da proteína durante o desenovelamento térmico / Abstract: This work aims to study the thermally!induced conformational transitions in Ribonuclease A. This approach was performed by applying the technique of differential scanning calorimetry (DSC) and medium infrared Fourier transform spectroscopy (FTIR), linking the technique of correlation analysis (2D!COS), variable!variable (VV) and sample !sample (SS). From DSC data determine the enthalpy change of the system (SHcal) which was 587 kJ / mol. We identified the pre temperatures (36, 39, 43, 49 and 59 ° C), post transition (71 ° C) and melting temperature (65 ° C), besides determination of SHcal for each transition. The two!dimensional correlation analysis sample! sample (SS) was also able to identify the same temperatures found by DSC. In turn, the two!dimensional correlation analysis of variable!variable (VV) described the conformation evolution of the protein secondary structures during thermal unfolding / Mestre

Made available in DSpace on 2014-06-11T19:22:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-05-27Bitstream added on 2014-06-13T20:29:19Z : No. of bitstreams: 1 martins_db_me_sjrp.pdf: 1774906 bytes, checksum: cae913e873e102a5cfd5c4dddccc9e4d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esse trabalho tem por objetivo estudar as transições conformacionais, induzidas termicamente, na Ribonuclease A. Esta abordagem foi realizada aplicando!se a técnica de calorimetria diferencial de varredura (DSC) e infravermelho médio com transformada de Fourier (FTIR), associando a técnica de análise de correlação bidimensional (2D! COS), variável!variável (VV) e sample sample (SS). A partir dos dados de DSC determinamos a variação de entalpia do sistema (∆Hcal) que foi de 587 kJ/mol. Também identificamos as temperaturas de pré (36, 39, 43, 49 e 59°C), pós transição (71°C) e temperatura de melting (65°C), além da determinação do ∆Hcal para cada uma das transições. A análise de correlação bidimensional sample!sample (SS) também foi capaz de identificar as mesmas temperaturas encontradas por DSC. Por sua vez, a análise de correlação bidimensional variável!variável (VV) descreveu a evolução conformacional das estruturas secundárias da proteína durante o desenovelamento térmico / This work aims to study the thermally!induced conformational transitions in Ribonuclease A. This approach was performed by applying the technique of differential scanning calorimetry (DSC) and medium infrared Fourier transform spectroscopy (FTIR), linking the technique of correlation analysis (2D!COS), variable!variable (VV) and sample !sample (SS). From DSC data determine the enthalpy change of the system (SHcal) which was 587 kJ / mol. We identified the pre temperatures (36, 39, 43, 49 and 59 ° C), post transition (71 ° C) and melting temperature (65 ° C), besides determination of SHcal for each transition. The two!dimensional correlation analysis sample! sample (SS) was also able to identify the same temperatures found by DSC. In turn, the two!dimensional correlation analysis of variable!variable (VV) described the conformation evolution of the protein secondary structures during thermal unfolding

Orientador: Celio Pasquini / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-06T07:12:46Z (GMT). No. of bitstreams: 1 Pereira_ClaudeteFernandes_D.pdf: 2102754 bytes, checksum: 94aabfeb5b023dd70dc648a8f2343f52 (MD5) Previous issue date: 2006 / Resumo: A espectroscopia de correlação bidimensional (2D) foi utilizada neste trabalho como ferramenta de seleção de variáveis espectrais na região do infravermelho próximo (NIR) para a determinação dos seguintes parâmetros de qualidade de gasolinas: teor de etanol, MON e RON. Para tanto, foi sugerido um sistema de perturbação de concentração em fluxo. Tal sistema apresenta algumas vantagens em relação aos sistemas de perturbação em batelada: os experimentos são realizados em sistema fechado; uma maior velocidade na aplicação da perturbação é obtida, além de se trabalhar em micro-escala. Em outra etapa do trabalho, sugeriu-se a construção de um espectropolarímetro baseado em Filtro Óptico Acústico Sintonizável (AOTF) que opera na região do Infravermelho próximo (800 ¿ 1600 nm). A medida de rotação óptica no instrumento proposto é feita utilizando-se a razão entre os dois feixes difratados pelo AOTF (espectro de rotação óptica), a qual é proporcional ao ângulo de rotação da luz polarizada imposto pela amostra. O instrumento foi empregado na obtenção de espectros de rotação óptica na região NIR de sacarose, glicose, frutose e cânfora. Esses espectros são proporcionais às concentrações das espécies estudadas e curvas analíticas com bons coeficientes de correlação foram obtidas / Abstract: The two-dimensional correlation spectroscopy was used in this work as a tool for spectral variable selection in the near-infrared (NIR) region aiming the determination of the following quality parameters of gasoline: ethanol content, MON (Motor Octane Number) and RON (Research Octane Number). To achieve this objective, it was developed a flow system to automated the perturbation by concentration. This system presents some advantages in relation to batch systems employed to the same purpose: the experiments are accomplished in a closed system; a greater velocity in the application perturbation can be obtained and the experiments are made in micro-scale. In another part, this work presents the construction of a spectropolarimeter based on the acousto-optic tunable filter (AOTF), which works on the near-infrared region (800 ¿ 1600 nm). The measure of optical rotation on the instrument is made using the ratio between two diffracted beams by the AOTF (optical rotation spectrum), which is proportional to the rotation angle of the polarized light imposed by the sample. The instrument was applied in the investigation of NIR optical rotation spectra of sucrose, glucose, fructose and camphor. These spectra are proportional to the concentration of species studied and analytical curves with good correlation coefficients were obtained. / Doutorado / Quimica Analitica / Doutor em Ciências

Title: Study of protein structure and dynamics by means of optical spectroscopy Author: Tomáš Pazderka Institute: Institute of Physics of Charles University Supervisor: RNDr. Vladimír Kopecký, Ph.D., Institute of Physics of Charles University Abstract: The aim of this thesis is to improve understanding of protein structure and dynamics and extend experimental setup and data processing for such stud- ies. We focus on the extension of experimental feasability of vibrational optical activity (VOA). We have demonstrated a usability of intensity calibration in the field of Raman optical activity. Advantages for measurements on multiple instru- ments and/or using different configurations have been shown. A new instrumental setup has been developed for microsampling measurements of vibrational circular dichroism spectra with a spatial resolution of 1 mm. Using this technique, spatial inhomogeneities in a sample of protein fibrils have been observed. Model com- pounds for amide nonplanarity have been investigated utilizing several methods of optical spectroscopy and key spectral features for determination of amide non- planarity and the absolute configuration have been identified. A comprehensive set of Raman spectra of proteinogenic amino acids has been measured. Sample concentration dependencies and consequent...