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<p dir="ltr">Mass spectrometry (MS) is a powerful tool for analyzing complex mixtures, offering valuable information regarding identification and quantification for laboratory research, both fundamental and applied. Manipulating ions using electrostatic and electrodynamic fields in a vacuum environment, MS is inherently fast and capable of generating diverse structural information. However, the potential speed of MS analysis is often hindered due to the necessity of separating complex mixtures prior to injection into the mass spectrometer. In this dissertation, we demonstrate methods to improve the speed of mass spectrometric mixture analysis at every stage, from ionization to ion trapping, and eventually to data analysis.</p><p dir="ltr">One solution to the challenge of increasing speed is ambient ionization using nESI coupled with microdroplet-based reaction acceleration. During the travel of the microdroplet from the ionization source to the inlet of the mass spectrometer, a derivatization reaction was shown to increases the signal of compounds with a targeted functional group from the mixture within milliseconds. This eliminated the need for time-consuming chromatographical separation, allowing for class-based mixture analysis (<i>e.g.</i> phenolic compounds, chapter 2). This accelerated chemical reaction mechanism was studied using the Katritzky reaction and a large surface-to-volume ratio (chapter 3). It is suggested that acceleration is associated with an electric double layer, which creates a strong electric field near the air-liquid interface.</p><p dir="ltr">The second part of the discussion on speeding up mixture component identification uses a modified ion trap and a new scan type: two-dimensional tandem mass spectrometry (2D MS/MS). In this experiment, MS/MS data of all precursors is recorded without isolation, thereby allowing characterization of each molecule in the mixture using a single ion injection. The generated data is stored in an image format where one dimension represents the precursor domain while the other dimension represents the product <i>m/z</i> values. This allows for the structural interpretation of all mixture components from a single spectrum. Applications of this technology include developing point-of-care assays to analyze patient blood HIV drug levels in less than five minutes (chapter 5 and 6) and the <i>in-situ</i> analysis of sulfonamides in milk in less than one minute (chapter 7) using portable mass spectrometers.</p><p dir="ltr">The third improvement is focused on novel data analysis techniques. In one case, the effects of an accelerated reaction on a complex mixture were visualized using subtracted 2D MS/MS spectra, which provided an additional layer of information, speeding up the processing and interpretation of an unknown mixture (chapter 8). In another case, raw 2D MS/MS spectra were formatted and processed for machine learning analysis, which was used to classify and identify eight different bacteria based on lipid region profiles within seconds.</p>

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No / Recent studies relating to the analytical chemical characterization of terrestrial extremophiles reveal the presence of biomolecules that have been synthesized for the survival of the colonies in response to the extreme environmental conditions, where otherwise life could not exist. This is a vital part of the planned space missions now being undertaken to planets and their satellites in the search for extinct or extant life signatures in our Solar System. Extremophiles have existed on the Earth for some 3.8 Gyr and their interrogation indicates their strategic survival methods which can be associated and compared with extraterrestrial scenarios on Mars, Titan, Enceladus and Europa.

Diverse experimental techniques were used for the determination of acetaminophen (N-(p-Hydroxyphenyl)acetamide, N-acetyl-p-aminophenol) in aqueous and non-aqueous media. A study was performed on the electrochemical characterization of acetaminophen at a noble-metal electrode. A pretreatment procedure on the gold electrode was developed under basic conditions. The anodic peak current was the analytical parameter used. Spectrometric techniques were used as detection means, and their analytical potential was evaluated. Infrared techniques such as transmission and attenuated total internal reflection (ATR) were used for the quantitative determination of acetaminophen. The molar absorptivity of acetaminophen was calculated at the carbonyl infrared band from the calibration data obtained from the experiments performed in non-aqueous solvents using the transmission technique. The attenuated total internal reflection technique was used to overcome limitations on the use of the infrared transmission technique for aqueous based systems. A quantitative study was undertaken of the possibilities for the determination of acetaminophen in aqueous solutions by coupling flow injection analysis (FIA) with Fourier transform-infrared (FT-IR) spectrometry. Optimization of the basic flow injection FT-IR system was performed. The cylindrical internal reflection cell for liquid evaluation (CIRCLE$\sp\circler$) was used as the detector cell compatible with aqueous solutions. Applications to systems involving on-line chemical reactions by coupling the flow injection analysis technique with infrared spectrometric detection were described. Flow injection spectrophotometric and infrared detection methods were developed for the determination of acetaminophen based on its hydrolysis reaction with sodium hydroxide to form p-aminophenol and its oxidation with potassium ferricyanide to produce an orange-red species, p-benzoquinonemonoimine. The developed methods were evaluated by analysis of tablets of a commercial formulation. The ability of flow injection techniques for generating transient product profiles combined with the infrared mode for monitoring reaction species was investigated to help in the study of reaction mechanisms. Ab initio calculations were performed on acetaminophen at the 3-21G level of the theory. Structural parameters were optimized for the two conformations of acetaminophen. The calculated and experimental spectra were compared in terms of the infrared vibrational frequencies.

A buspirona, ansiolítico da segunda geração usada no tratamento de ansiedade, foi analisada fisico-quimica e quimicamente, com o objetivo de fornecer subsídios para a respectiva monografia. Fizeram-se os seguintes testes de caracterização deste fármaco: faixa de fusão, análise elementar, pH, umidade e solubilidade. Realizaram-se igualmente as provas de identificação constante de: análise cromatográfica, ensaio de cloreto, espectro no infravermelho, espectro no ultravioleta, espectro de ressonância magnética protônica, espectro de massa, espectro de carbono-13, termogravimetria, calorimetria exploratória diferencial e cromatografia líquida de alta resolução. Efetuaram-se, também, determinações quantitativas pelos seguintes métodos: micro-Kjeldahl, gravimétrico, potenciométrico com nitrato de prata, doseamento com ácido perclórico em meio acetico por volumetria e potenciometria e espectrofotométrico no ultravioleta. Concluiu-se que: 1) o teste de caracterização mais indicado e o ponto de fusão; 2) das provas de identificação, as mais simples e rápidas são as seguintes: identificação de cloreto, infravermelho e ultravioleta; 3) dos métodos de determinação quantitativa, mais prático e o doseamento com ácido perclórico em meio acético, usando como indicador o vermelho de quinaldina. / Buspirone, a new non-benzodiazepine anxiolytic agent which is effective in the treatment of anxiety, was analyzed by physicochemical and chemical methods, having in mind a monograph of this drug. The fo1lowing characterization tests of this drug were performed: melting range, elementary analysis, pH, loss in drying, solubility. The following identification tests were also carried out: chromatographic analysis, identification of chloride, infrared absorption, ultraviolet absorption, protonic magnetic resonance spectra, mass spectrum, carbon 13C NMR spectroscopy, thermogravimetry and high performance liquid chromatography. Quantitative determinations were obtained through the following methods: micro-Kjeldahl, gravimetry, potenciometry, non-aqueous titration with perchloric acid and ultraviolet spectrometry. The following conclusions were reached: 1) the best characterization test is the melting range; 2) the simplest and quickest tests of identification are: identification of chloride, infrared and ultraviolet spectrophotometry; 3) the most practical method is the non-aqueous assay with perchloric acid.

O presente trabalho versa sobre a modificação de eletrodos de carbono vítreo por óxidos de molibdênio e estudos referentes à catálise de redução de oxiânions, bem como o emprego do sensor assim preparado para análise de bromato e iodato em amostras sintéticas e naturais. Estudos executados em solução contendo Mo (VI) na faixa de pH de 1,8 a 3,0 indicaram que em meios mais ácidos a resposta catalítica é muito maior, envolvendo a participação de prótons na abstração de oxigênio ao reduzir o substrato. Os resultados dos experimentos voltamétricos realizados com eletrodo de carbono vítreo modificado demonstraram que iodeto é gerado na eletroredução de iodato. O processo de modificação do eletrodo consistiu na execução de experimentos voltamétricos sucessivos com o eletrodo de carbono vítreo em solução contendo Mo (VI), em pH ajustado para otimização da formação do filme e minimização das perdas de depósito por solubilização ácida. O material imobilizado assim obtido foi analisado por técnicas espectrais e microscópicas, observando-se a existência de centros preferenciais de formação de depósito (grumos) ao qual foi atribuída a fórmula mínima de MoO2,78. O óxido de valência mista mostrou grande potencialidade de catálise na redução de oxiânions oxidantes, observando-se antecipação do potencial de redução do iodato, acompanhada de grande intensificação no sinal de corrente. Trabalhando-se em condições de convecção forçada regida pela rotação do eletrodo de trabalho, foram observadas anomalias nos sinais de corrente durante o decorrer dos experimentos eletroquímicos. Explicações para tal fato foram associadas à formação de diferentes fases de óxidos de molibdênio com atividades catalíticas distintas. O sensor desenvolvido para determinação de iodato foi utilizado em sistema em fluxo após otimização de parâmetros como pH do transportador e da amostra, bem como condições relacionadas à modificação do eletrodo (espessura do filme). Amostras de sal de cozinha foram analisadas pelo método proposto e os resultados obtidos foram concordantes com aqueles oriundos do emprego de metodologia padrão. / The electroreduction of both iodate and bromate at glassy carbon discs modified by molybdenum oxide films in sulfuric acid medium is discussed. Studies carried out at the 1.8 - 3.0 pH range with Mo(VI) in solution show that at more acidic conditions the catalytic response is much larger since protons participate in the oxygen abstraction step when the substrate is reduced. The results of voltammetric experiments carried out with a glassy carbon electrode coated by the molybdenum oxide layer established that iodide is generated in the electroreduction of iodate. The electrochemical modification of the glassy carbon electrode was carried out by cycling consecutively the potential in a solution containing Mo(VI) at a convenient pH. At the optimal condition an adherent film is obtained and the acidic solubilisation is minimised. The immobilised material was analysed by spectral techniques and scanning electronics microscopy, indicating the existence of preferential centres of deposition of material whose formula was calculated to be MoO2,78. The electroreduction of the analyte occurs at a glassy carbon disc modified electrode, the film acting as an efficient electrocatalyst for the mass transport controlled reduction. Rotating disc experiments performed in solutions containing both Mo(VI) and iodate at pH 1.8 confirmed that an immobilised form of molybdenum is responsible for the reduction of the substrate, even though at more acidic solutions the film is partially solubilised. The response from chronoamperometric experiments shows unexpected results explained by the existence of different catalytic species in equilibrium as two distinct phases with different catalytical activity. A method for the amperometric determination of iodate with the modified electrode in a flow injection configuration was described and the sensor was applied to the determination of iodate in commercial salt samples in a wall-jet cell coupled to a flow injection apparatus after convenient desoxygenation of the carrier solution.

A buspirona, ansiolítico da segunda geração usada no tratamento de ansiedade, foi analisada fisico-quimica e quimicamente, com o objetivo de fornecer subsídios para a respectiva monografia. Fizeram-se os seguintes testes de caracterização deste fármaco: faixa de fusão, análise elementar, pH, umidade e solubilidade. Realizaram-se igualmente as provas de identificação constante de: análise cromatográfica, ensaio de cloreto, espectro no infravermelho, espectro no ultravioleta, espectro de ressonância magnética protônica, espectro de massa, espectro de carbono-13, termogravimetria, calorimetria exploratória diferencial e cromatografia líquida de alta resolução. Efetuaram-se, também, determinações quantitativas pelos seguintes métodos: micro-Kjeldahl, gravimétrico, potenciométrico com nitrato de prata, doseamento com ácido perclórico em meio acetico por volumetria e potenciometria e espectrofotométrico no ultravioleta. Concluiu-se que: 1) o teste de caracterização mais indicado e o ponto de fusão; 2) das provas de identificação, as mais simples e rápidas são as seguintes: identificação de cloreto, infravermelho e ultravioleta; 3) dos métodos de determinação quantitativa, mais prático e o doseamento com ácido perclórico em meio acético, usando como indicador o vermelho de quinaldina. / Buspirone, a new non-benzodiazepine anxiolytic agent which is effective in the treatment of anxiety, was analyzed by physicochemical and chemical methods, having in mind a monograph of this drug. The fo1lowing characterization tests of this drug were performed: melting range, elementary analysis, pH, loss in drying, solubility. The following identification tests were also carried out: chromatographic analysis, identification of chloride, infrared absorption, ultraviolet absorption, protonic magnetic resonance spectra, mass spectrum, carbon 13C NMR spectroscopy, thermogravimetry and high performance liquid chromatography. Quantitative determinations were obtained through the following methods: micro-Kjeldahl, gravimetry, potenciometry, non-aqueous titration with perchloric acid and ultraviolet spectrometry. The following conclusions were reached: 1) the best characterization test is the melting range; 2) the simplest and quickest tests of identification are: identification of chloride, infrared and ultraviolet spectrophotometry; 3) the most practical method is the non-aqueous assay with perchloric acid.

Extraction of the lipids of Legionella pneumophila yields phases unlike those produced from other Gram-negative bacteria. A viscous interface forms between the aqueous (wash) and organic phases. More than half of the hydroxylated fatty acids were found distributed between the aqueous phase and the interfacial material, fractions in which such constituents have not been reported in other Gram-negative species. It was further observed that after the material from the aqueous/interfacial phase was dissolved in methanol or chloroform/methanol (2:1 (V/V)), the addition of acetone would create a white, flocculent precipitate. Analyses showed that the supernatant contained fatty acids that were nonhydroxylated and the precipitate contained both nonhydroxylated and hydroxylated fatty acids. The acetone precipitate could be further purified by column chromatography. Material was eluted from a silicic acid column with sequential additions of chloroform, acetone, and methanol. It was found that the methanol fraction contained the majority of the hydroxylated fatty acid containing material. An improved method for extracting LPS-like material from Legionella pneumophila is presented. This study suggests that LPS-like material can be obtained from L. pneumophila in higher yield (6.4% of total cell weight), of higher purity (as indicated by SDS-PAGE), and by a simpler method than those previously reported. SDS-PAGE profiles of purified (acetone precipitation and column chromatographic separation) LPS-like material extracted with chloroform/methanol (2:1 (V/V)) from L. pneumophila are identical to the previously reported profiles for G. pneumophila LPS. The chemical analyses of the LPS-like material can only account for approximately one-half the isolated material weight. This is suggestive of a moiety that is as of yet undetectable by the means employed to characterize the LPS.