Banca de DEFESA: ARQUIMEDES MORAES SOUZA COUTINHO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : ARQUIMEDES MORAES SOUZA COUTINHO
DATE: 16/12/2021
TIME: 08:00
LOCAL: Videoconferência
TITLE:

INVESTIGATION OF A POTENTIAL BIOMARKER FOR THERMAL EVOLUTION OF OIL BY ULTRA-HIGH RESOLUTION MASS SPECTROMETRY

KEY WORDS:

Biomarker; thermal evolution; mass spectrometry; petroleomics.

PAGES: 133
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Análise de Traços e Química Ambiental
SUMMARY:

Gas Chromatography Coupled to Mass Spectrometry (GC-MS) has been historically used for the identification of classical oil biomarkers, getting geochemical properties, including the degree of thermal evolution that indicates the thermal maturity as a function of the formation temperature of oil reservoirs. However, GC-MS methods require a large data analysis and processing time. A recent and fast technique, named as Fourier Transform Ultra-High Resolution Mass Spectrometry (FT-MS) has demonstrated a high potential for crude oils chemical characterization. The study aims to investigate a new potential oil biomarker using FT-MS analyses to obtain a thermal evolution compound detected in a simpler and faster way than those by classical methods employing GC-MS. A total of 14 standard compounds that are typically present in crude oils (classes of thiophenes, pyridinols, carboxylic acids, alcohols, ketones and hydrocarbons) were investigated and analyzed by FT-MS using electrospray ionization (ESI). Standard compounds were also subjected to analytical micropyrolysis (Py) at temperatures up to 500 ºC, aiming to simulate thermal processes. Furthermore, as proof of concept, four crude oils samples with different degrees of thermal evolution measured by GC-MS were also analyzed by FT-MS. Among all the standard compounds analyzed, the Py data of 2,3-dimethyl-pyridin-4-ol obtained by FT-MS in the ESI(-) mode (m/z 122.06021, molecular formula C7H8ON) showed the formation of ions with m/z and molecular formulas: 122.06021 (C7H8ON); 241.09818 (C14H13O2N2); 348.17201 (C21H22O2N3) and 453.23002 (C28H29O2N4), which suggested that thermal processing leads to the formation of new compounds. Comparing these data with the MS of the four crude oils obtained by ESI(-) FT-MS, it was determined the presence of the same ions, indicating that they are compounds formed in the process of thermal evolution of oils. Therefore, linear correlations were found between the abundances of ions with m/z 122.06015 and 241.09807 (referring to 2,3-dimethyl-pyridin-4-ol and its Py product) and the diagnostic ratios for thermal evolution using classical biomarkers obtained by GC-MS. Thus, we conclude that 2,3-dimethyl-pyridin-4-ol proved to be a potential biomarker to determine the thermal evolution of crude oils, and could be used as an alternative for geochemical studies.

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