Simultaneous extraction and fractionation of petroleum biomarkers from tar balls and crude oils using a two-step sequential supercritical fluid extraction

In this study a novel sustainable method based on supercritical fluid extraction (SFE) method was developed for simultaneous extraction and fractionation of petroleum biomarkers. We herein proposed a two-step supercritical fluid extraction method for crude oil and tar ball to separate the petroleum biomarkers into aliphatic and aromatic fractions. In the first step, pure scCO₂ was used, while scCO₂ modified was used as a solvent in the subsequent step. CO₂ SFE can serve as an environmental-friendly alternative to common column chromatography method for petroleum biomarker or compositional analysis by GC-MS. The extraction process was shown to be selective, according to the polarity of the solvent, providing fractionation of aliphatic and aromatic hydrocarbons. Yet the total extraction procedure in SFE was significantly faster than column chromatography methods (~80 min vs. 8 h). We will discuss the implications of this SFE method as a novel sustainable alternative to the existing extraction techniques.