GC–MS detection and significance of crocetane and pentamethylicosane in sediments and crude oils

摘要: Abstract The occurrence of the archaeal biomarkers crocetane and pentamethylicosane (PMI) in sediments crude oils was investigated using GC–MS GC–MS–MS. Selected ion monitoring (SIM) multiple reaction (MRM) protocols designed to detect C 20 25 irregular isoprenoids were evaluated. A method for preferential detection over phytane, its more abundant isomer, refined authentic compounds. Crocetane found be present modern from both aerobic anaerobic water columns sediment 1640 Ma Barney Creek Formation, providing evidence antiquity biosynthesis. also detected several Perth Basin Kockatea shale, their putative source rock, Canning oils, although MRM analysis could only verify Devonian age. Equivocal data Ordovician Carboniferous highlight need extreme caution when attempting distinguish between acyclic isoprenoid isomers. PMI identified by a Miocene Monterey Antarctica sediment. On other hand, hydrocarbon peak Triassic older consistently as regular isomer (I reg ) whenever it sufficiently applied.