Identification of a novel C33 n-alkylcyclohexane biomarker in Permian–Triassic sediments

A C33 n-alkylcyclohexane (n-heptacosylcyclohexane) has been used as a biomarker for oil correlation studies in the Perth Basin (Basal Triassic, Western Australia) for almost two decades, but the compound has never been formally identified. We now confirm the identification using two Perth Basin source rock samples by comparison of mass spectra and gas chromatographic retention behaviour on three GC stationary phases with an authentic reference compound. Recently, the C33 n-alkylcyclohexane has been reported to occur in several samples from a key Permian–Triassic section of Eastern Greenland.