Banca de QUALIFICAÇÃO: ARKELLAU KENNED SILVA MOURA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: ARKELLAU KENNED SILVA MOURA
DATA: 05/08/2022
HORA: 09:00
LOCAL: VIRTUAL
TÍTULO: Unequivocal identification of novel α,ω-bis(aryl)alkanes in a Cretaceous crude oil
PALAVRAS-CHAVES: α,ω-bis(aryl)alkanes; GC−MS/MS; GC×GC-TOFMS; coinjection; Brazilian Cretaceous crude oil; extended n-alkylaromatics
PÁGINAS: 45
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Orgânica
ESPECIALIDADE: Síntese Orgânica
RESUMO:

The α,ω-bis(aryl)alkanes (α,ω-BA) are uncommon biomarkers and have been hardly detected on geological samples. There were successful efforts to tentatively identify α,ω-BA in crude oils samples from Sergipe-Alagoas Basin, Brazil, but until now the unequivocal isomers series identification supported by coinjection and comparison with authentic standards remained unsettled. GC−tandem MS (GC−MS/MS) was applied to identify the α,ω-BA diaromatic isomers series in a crude oil sample (SEAL) from the Sergipe-Alagoas Basin, Brazil. Previous geochemical data indicate SEAL lacustrine paleo-depositional environment. α,ω-BA isomers series were identified using diagnostic ions (i.e., m/z 92 for α,ω-diphenylalkanes and α,ω-cyclohexyl-phenyl-alkanes, and m/z 106 for α,ω-phenyl-toluyl-alkanes and α,ω-bis(o-, m-, or p-toluyl)-alkanes), selected reaction monitoring transitions (MRM: 224 → 92; 230 → 92; 238 → 106; 252 → 106), and coinjection with synthesized authentic standards. Despite their occurrence both on lacustrine and marine oils, α,ω-BA have been associated with sulfur bacteria and euxinia and, thereupon, marine organic matter, probably due to their clear abundance differences in lacustrine and marine oils.  However, the organic matter sources of α,ω-BA, and their geochemical significance are still unknown. The unequivocal identification of α,ω-bis(aryl)alkanes in Brazilian Cretaceous crude oil raises new assignments to the contribution of organic matter and its geochemical significance. Additionally, extended series of n-alkylaromatics such as indanes, tetralins, and naphthalenes were identified by GC×GC-TOFMS in SEAL oil and first-time reported. Previous data infer a syngenetic relationship between them. Besides, new tetralin derivatives tentatively identified based on mass spectra (EI, 70 eV) are reported.

MEMBROS DA BANCA:
Presidente - 1167257 - ANTONIA MARIA DAS GRACAS LOPES CITO
Interno - 1167592 - MARIANA HELENA CHAVES
Interno - 1549302 - SIDNEY GONCALO DE LIMA
Externo ao Programa - 3248485 - GUSTAVO RODRIGUES DE SOUSA JÚNIOR
Externo à Instituição - BRUNO QUIRINO ARAÚJO - UFPI