Oleanane or lupane? Reappraisal of the presence of oleanane in Cretaceous–Tertiary oils and sediments

GC-MS analysis of penta- and tetra-cyclic triterpenes from resins ofPistacia species. Part I.Pistacia lentiscus var. Chia

“…The loss of 43 mass units (C 3 H 7 ) is ORIGINAL RESEARCH 292 A. N. Assimopoulou and V. P. Papageorgiou derivative, while it is not observed in lupanes. According to Nytoft (2002), the mass spectra of lupane and oleananes are very similar, except for the presence of an m/z 369 fragment and larger m/z 123 and 231 fragments in the lupane spectrum. The m/z 369 fragment ion is generated by loss from the lupane structure of an isopropyl side chain, which is not present in oleanane.…”

Potential petroleum source rocks in a tertiary sequence of the Eastern Venezuelan Basin

“…2, Table 2), the presence of 18a(H)-oleanane and the relatively low abundance of tricyclic terpane (Fig. 4) support the terrigenous organic matter input during sedimentation (Philp and Gilbert, 1985;Holba et al, 1988;Moldowan et al, 1994;Peters et al, 2005;Nytoft et al, 2002). Additionally, the ternary diagram showing the relative abundance of C 27 , C 28 and C 29 steranes supports the mixed source of the organic matter, with high input from higher-plant organic matter, according to the field assigned by Liu and Lee (2004) for terrigenous organic matter (Fig.…”

Comparison of GC–MS, GC–MRM-MS, and GC × GC to characterise higher plant biomarkers in Tertiary oils and rock extracts

“…The terrigenous signatures in the Arctic rock extracts are mainly attributed to relatively abundant oleanoids (Moldowan et al, 1994;Nytoft et al, 2002), lupanoids, isopimarane (V), abietane (VI) or simonellite (VII) (Otto and Wilde, 2001). Extract S1 is the oldest sample in the set (Late Paleocene, Table 2) and is dominated by conifer biomarkers like isopimarane (V), norisopimarane (VIII), cadalene (IX), and simonellite (VII) as opposed to angiosperm biomarkers, which is consistent with its age.…”

“…Such mixtures are very challenging to separate chromatographically due to their nearly identical structures, which result in very similar elution properties. 18a(H)-and 18b(H)-oleanane (I and II), for example, co-elute on typical non-polar columns (1D GC-MS; Nytoft et al, 2002) and have similar mass spectra, thus preventing separation based on mass spectral characteristics. GC Â GC was proven to effectively resolve stereoisomers of hopanes and steranes (Frysinger and Gaines, 2001;Silva et al, 2011) and thus appears to be the preferred choice to study minor components in complex mixtures of isomeric plant biomarkers.…”