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A GC×GC‐ToFMS Investigation of the Unresolved Complex Mixture and Associated Biomarkers in Biodegraded Petroleum
Author(s) -
WANG Guangli,
SIMONEIT Bernd Rolf Tatsuo,
SHI Shengbao,
WANG Tieguan,
ZHONG Ningning,
WANG Peirong
Publication year - 2018
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.13688
Subject(s) - phytane , brackish water , source rock , petroleum , geology , gas chromatography , chemistry , paleozoic , precambrian , environmental chemistry , chromatography , geochemistry , pristane , hydrocarbon , organic chemistry , paleontology , structural basin , oceanography , salinity
Heavy biodegraded crude oils have larger numbers of coeluting compounds than non‐ biodegraded oils, and they are typically not resolved with conventional gas chromatography (GC). This unresolved complex mixture (UCM) has been investigated using comprehensive two‐ dimensional gas chromatography–time‐of‐flight mass spectrometry (GC×GC‐ToFMS) within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan (Neoproterozoic, marine), Tarim (Early Paleozoic, marine), Bohai Bay (Eocene, saline/brackish) and Pearl River Mouth (Eocene, freshwater). In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A‐norsteranes, series of 1,1,3‐trimethyl‐2‐ alkylcyclohexanes (carotenoid‐derived alkanes), and tetralin and indane compounds, respectively.