Banca de DEFESA: FÁBIO XAVIER ANTUNES SAMPAIO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : FÁBIO XAVIER ANTUNES SAMPAIO
DATA : 26/08/2020
HORA: 14:00
LOCAL: Instituto de Química
TÍTULO:

Optimization of an analytical methodology for the sulfur markers determination in petroleum by GC-MS/MS

PALAVRAS-CHAVES:

petroleum, organic sulfur markers, GC-MS/MS

PÁGINAS: 125
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Separação
RESUMO:

Dibenzothiophene (DBT), benzothiophene (BT) and their alkylated homologous are important sulfur organic compounds (OSC) present in low concentrations in petroleum. The occurrence and distribution of these OSC in crude oils are used as markers of maturity, biodegradation and depositional environment. Traditionally, the characterization of crude oils involves several stages of sample preparation based on the separation by groups according to the polarity of the compounds and subsequent analysis of the fractions separated by GC-MS. The aim of the present study was to employ gas chromatography coupled with triple quadrupole mass spectrometry (GC-MS/MS) for the determination and quantification of OSC markers (classes BT, DBT and naphthobenzothiophene) in crude oil samples. Initially, a GC-MS/MS method was optimized using a mix containing fourteen OSC standards in full scan mode (SCAN) to obtain the mass spectrum, retention time of each compound and observe the separation between them. Optimization was also carried out for the selective ion monitoring mode (SIM) and in the multiple reaction monitoring mode (MRM) to define the collision cell energy used in this operational mode. The optimized method was initially applied to an oil sample, with no previous fractionation stage, in a qualitative way in a comparative study, based on selectivity and signal intensity in order to verify the effectiveness of the MRM method compared to the SIM mode. The results of the SIM and MRM modes indicate that the GC-MS/MS approach in the MRM mode achieved greater specificity and sensitivity for determining CSO. The MRM method was then applied to quantify eight samples of crude oil from the Potiguar Basin without fractionation steps. Finally, diagnostic reasons, based on sulfur markers such as: DBT / Phen; 4- / 1-MDBT; 2.4-/1.4 DMDBT; 4,6-/1,4-DMDBT; 1-MDBT/DBT were calculated and interpreted. It was concluded that the optimized GC-MS / MS method in MRM mode eliminated the need for fractionation and was efficient for the quantification of OSC markers and represents an analytical advance in the area of sulfur markers in oil samples. In addition, it made it possible to evaluate, through diagnostic reasons, together with other parameters, the degree of maturity, biodegradation and depositional environment in oil samples from the Potiguar Basin.

MEMBROS DA BANCA:
Presidente - 1303987 - MARIA ELISABETE MACHADO
Interno - 1553299 - GISELE OLIMPIO DA ROCHA
Interno - 285528 - VANIA PALMEIRA CAMPOS
Externo à Instituição - GABRIELA PEREIRA DA SILVA MACIEL - UFRGS
Externo à Instituição - KARINA SANTOS GARCIA - UFBA
Externo à Instituição - LAIZA CANIELAS KRAUSE - UNIT