Petroleomics by FT-ICR MS : evaluating the crude oil polar compounds ionization efficiency

Orientador: Marcos Nogueira EberlinDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de QuímicaResumo: Esse trabalho tem como objetivo conhecer e avaliar a ionização dos compostos polares no petróleo for Espectrometria de Massas por Ressonância Ciclotrônica de Íons com Transformada de Fourier (FTICR MS do inglês Fourier Transform Ion Cyclotron Resonance Mass Spectrometry), relacionando essa ionização com parâmetros experimentais e características intrínsecas das moléculas. No Capítulo 1 o tipo de amostra de interesse (petróleo) é abordado, tanto em suas características quanto em sua análise, definindo petroleômica e sua função. A espectrometria de massas é apresentada, então, como ferramenta de grande utilidade nos estudos petroleômicos, em especial aquela de ultra alta resolução como FTICR MS (Fourier Transform Ion Cyclotron Resonance Mass Spectrometry) acoplada a fonte de ionização eletrospray (ESI). No Capítulo 2 a ferramenta estatística do planejamento de experimentos é apresentada e, então, utilizada em uma amostra real de petróleo de forma a relacionar os parâmetros operacionais da fonte de ESI com respostas avaliadas comumente em petroleômica. Aspectos interessantes das relações parâmetro-resposta surgem durante o estudo, mostrando que a análise de petróleo por ESI-FTICR MS, apesar de largamente utilizada na literatura, não é trivial e precauções devem ser tomadas durante a otimização dos parâmetros experimentais. No Capítulo 3 as técnicas de APCI (Atmospheric Pressure Chemical Ionization) e APPI (Atmospheric Pressure PhotoIonization) são abordadas e utilizadas, juntamente com ESI, para avaliar a ionização de padrões de compostos similares àqueles encontrados nas principais classes de compostos polares do petróleo. A análise pelas técnicas que ionizam de forma mais abrangente os compostos apresentaram comportamentos que tornam tais análises inviáveis. Uma reação de metilação que melhora a ionização de compostos sulfurados também é realizada em duas condições, comparando-se tais condições a partir dos espectros obtidos após suas análises. Conhecendo a ionização desses compostos padrões, é possível entender a petroleômica de forma mais ampla dando maior confiabilidade para estabelecer as relações composição-comportamento do petróleoAbstract: The aim of this work is to know and evaluate the crude oil polar compounds ionization through Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, relating this ionization with experimental parameters and intrinsic characteristics of molecules. On Chapter 1 the sample of interest (crude oil) is addressed, both in its characteristics and its analysis, defining petroleomics and its function. Mass spectrometry is then presented as a tool of great utility in petroleomic studies, in special the ultra high resolution one as FTICR MS coupled to eletrospray Ionization (ESI). On Chapter 2 the design of experiment statistic tool is presented and used in a real crude oil sample in order to relate operational parameters of ESI source to commonly evaluated responses in petroleomics. Interesting aspects regarding parameter-response relationships arises during the study, showing that the crude oil analysis using ESI-FTICR MS, while it is largely used in literature, it is not trivial and precautions have to be taken during the optimization of experimental parameters. On Chapter 3 APCI (Atmospheric Pressure Chemical Ionization) and APPI (Atmospheric Pressure PhotoIonization) technics are addressed and used, along with ESI, to evaluate the ionization of standard compounds similar to those polar compounds found in crude oil. Analysis using sources that ionizes in the most comprehensive way has shown such behavior that makes the analysis unviable. A methylation reaction that improves the ionization of sulfur compounds is also made on two conditions, comparing these conditions through the obtained spectra after their analysis. By knowing the ionization of these standard compounds it is possible to understand the petroleomics in a much comprehensive way, providing reliability to stablish composition-behavior relations of crude oilMestradoQuimica OrganicaMestre em Químic

The challenge of the chemical characterization of emulsified crude oil asphaltenes employing petroleomic studies by FT-MS

Orientador: Marcos Nogueira EberlinTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuímicaResumo: É cada vez maior a necessidade de a indústria de petróleo realizar a extração e refino de óleos brutos pesados, contendo compostos mais polares e de elevada aromaticidade, presentes principalmente em frações pouco conhecidas como os asfaltenos. Mesmo com o advento de técnicas analíticas que atingem compostos mais pesados, como a espectrometria de massas por ressonância ciclotrônica de íons com transformada de Fourier (FT-ICR MS), pouco ainda se conhece da estrutura e composição química dos asfaltenos. A micropirólise se apresenta como uma técnica interessante para desvendar essas estruturas, já que permite a quebra dos compostos com menor influência externa. Nesse contexto, dez óleos da bacia Sergipe-Alagoas tiveram seus asfaltenos precipitados em n-pentano e n-heptano e analisados por FT-ICR MS acoplado às técnicas de APPI(±) e ESI(±). Foram utilizados diferentes aditivos para aumentar a abrangência das análises, com os asfaltenos sendo analisados antes e depois de um processo de micropirólise. Os dados foram comparados com base na composição heteroatômica, aromaticidade e íons em comum, auxiliada por análise quimiométrica para diferenciar os grupos de amostras. Os resultados mostraram que os asfaltenos precipitados em n-pentano possuem um caráter mais polar e ácido, enquanto que os de n-heptano se destacam pela aromaticidade. Com técnica de APPI(±) uma parcela dos compostos asfaltênicos foi detectada, diretamente dos óleos brutos, enquanto que a utilização de diferentes métodos para ESI(-) mostrou que os principais compostos ácidos dos asfaltenos são os derivados de carbazóis. A utilização de micropirólise indicou que os compostos asfaltênicos são formados por diversos núcleos aromáticos interconectados por grupos alifáticos. As quebras das ligações simples entre os núcleos aromáticos diminuíram a complexidade heteroatômica dos asfaltenos, comprovando que os heteroátomos não estão agrupados, mas sim distribuídos ao longo da molécula em grupos aromáticos, auxiliando a formação de emulsão por meio desses compostosAbstract: There is an increasing need for the oil industry to extract and refine heavy crude oils containing more polar compounds with high aromaticity, present mainly in little known fractions as asphaltenes. Even with the advent of analytical techniques that reach heavier compounds, such as mass spectrometry by cyclotron resonance of Fourier transform ions (FT-ICR MS), little is known about the structure and chemical composition of asphaltenes. Micropirolysis is an interesting technique to unravel these structures, since it allows the breaking of the compounds with less external influence. In this context, ten oils from the Sergipe-Alagoas basin had their asphaltenes precipitated in n-pentane and n-heptane and analyzed by FT-ICR MS coupled with APPI (±) and ESI (±) techniques. Different additives were used to increase the range of the analyzes, with asphaltenes being analyzed before and after a micropirolysis process. The data were compared based on heteroatom composition, aromaticity and ions in common, aided by chemometric analysis to differentiate groups of samples. The results showed that the asphaltenes precipitated in n-pentane have a more polar and acidic character, whereas those of n-heptane are distinguished by aromaticity. With APPI (±) technique, a portion of the asphaltene compounds was detected directly from the crude oils, whereas the use of different methods for ESI (-) showed that the main acid compounds of asphaltenes are those derived from carbazoles. The use of micropirolysis indicated that asphaltene compounds are formed by various aromatic nuclei interconnected by aliphatic groups. The breaking of single bonds between the aromatic nuclei diminished the heteroatomic complexity of the asphaltenes, proving that the heteroatoms are not grouped, but distributed throughout the molecule in aromatic groups, aiding the formation of emulsion by means of these compoundsDoutoradoQuimica OrganicaDoutor em Ciências140382/2016-0CNP

Comprehensive characterization of asphaltenes by fourier transform ion cyclotron resonance mass spectrometry precipitated under different n-alkanes solvents

CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOAsphaltenes are still problematic fractions and their composition is not fully unveiled as it relates to the original crude oil and the precipitation method. In this work, the composition of asphaltenes precipitated with n-heptane and n-pentane from ten c32210381046CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOsem informação140382/2016-02013/19161-

Comprehensive Characterization of Asphaltenes by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Precipitated under Different <i>n</i>‑Alkanes Solvents

Asphaltenes are still problematic fractions and their composition is not fully unveiled as it relates to the original crude oil and the precipitation method. In this work, the composition of asphaltenes precipitated with <i>n</i>-heptane and <i>n</i>-pentane from ten crude oils from the Sergipe-Alagoas Basin were assessed by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) using five ionization procedures (electrospray ionization (ESI), ESI­(+) with formic acid, ESI(−) with ammonium hydroxide, and ESI(−) with tetramethyl­ammonium hydroxide, and atmospheric pressure photoionization (APPI), APPI­(+) and APPI(−)) in combination with a 7.2 T LTQ FT Ultra Thermo Fisher spectrometer. The purpose was to evaluate compositional differences between C5- and C7-asphaltenes according to the adopted ionization methodologies. Asphaltenes were compared as a function of heteroatomic composition and aromaticity. Chemometrics strategies were employed to evaluate the heteroatom classes of higher variation among the groups. Ions that were shared by the asphaltenes and the crude oils and between the ionization methods were also evaluated for similarity. Results showed that <i>n</i>-heptane asphaltenes are more aromatic than <i>n</i>-pentane asphaltenes, which in turn were found to be more acidic and to display a higher heteroatomic complexity. Principal component analysis and the evaluation of shared ions showed that APPI(±) is able to detected asphaltene ions directly from the whole crude oil. It was also found that the use of different ionization methods with and without additives is fundamental to obtain more comprehensive chemical profiles in terms of classes and their constituents for crude oils and their asphaltenes and that the specific <i>n</i>-alkane used to precipitate asphaltenes leads to different chemical profiles

AVALIAÇÃO DA EXTENSÃO DA BIODEGRADAÇÃO DE PETRÓLEOS BRASILEIROS COM ÊNFASE NOS N-ALQUILCICLOHEXANOS

The n-alkylcyclohexanes are poorly evaluated in biodegradation studies of Brazilian petroleum samples. In this context, this work aimed to use the homologue series of alkylcyclohexanes to assess extend of biodegradation of 26 petroleum samples from five Brazilian sedimentary basins, analyzed by gas chromatography coupled to mass spectrometry. The n-alkylcyclohexanes compounds were detected in all samples, with a distribution similar to the n-alkane profile, in which their abundance decreasing with increasing of the biodegradation extent. Based on this, it was suggested the use of the new parameter H30/DC together with the H30/AC already proposed, calculated by the ratio between C30 hopane to the dodecyl-cyclohexane, to assess biodegradation level according Peter and Moldowan scale (PM scale). In addition, it was observed an increasing in the relative abundance of DBE 2 from class O2, analyzed by ESI(-) FT-ICR MS, mainly due to the formation of monocyclic acids with biodegradation, which correlates with the decrease of n-alkylcyclohexanes, a possible precursor of these acids

Fecal bile acid profile after Roux-en-Y gastric bypass and its association with the remission of type 2 diabetes in obese women : a preliminary study

To assess the influence of Roux-en-Y gastric by-pass (RYGB) on fecal bile acid (BA) profile and its relationship with postoperative remission of type 2 diabetes (T2D). Fecal samples were collected 3 and 12 months after RYGB from diabetic obese women who were responsive (n = 12) and non-responsive (n = 8) to postoperative remission of T2D. Fecal BA profile was accessed by liquid chromatography coupled to tandem mass spectrometry in a targeted approach. Relative to pre-operative levels, a total of 10 fecal BA profiles decreased after RYGB (ANOVA, p <= 0.05) with significant fold-changes for glycochenodeoxycholic, glycocholic, taurocholic, and taurochenodeoxycholic acids at 3-months postoperatively, and for glycochenodeoxycholic, glycocholic and taurocholic acids at 12 months postoperatively (Benjamini-Hochberg, p < 0.05). Postoperative changes in fecal BA were different between responsive and non-responsive women, with a significant reduction in more sub-fractions of BA in responsive women than in non-responsive women, and a marked difference in the temporal behavior of cholic acid (CA) and chenodeoxycholic acid (CDCA), thus reflecting changes in CA/CDCA ratio, and tauroursodeoxycolic (TUDCA) levels between these responsiveness groups (ANOVA, p <= 0.05). RYGB induces a marked reduction in the concentration of fecal BA, which is heterogeneous according to T2D responsiveness38629062912FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPFAPESP 2011/09612-3, 2014/05220-1The authors thank the patients who participated in the study and Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) and Nestlé Health Scienc