Polycyclic isoprenoids

Polycyclic isoprenoids are divided into groups based on how many C₁₀ units, or we say terpenoids their precursors possessed. Thus, for example, a triterpane had a precursor that had between 30 and 40 carbons.

• Monoterpenoids, C₁₀
• Diterpenoids, C₂₀
• Triterpenoids, C₃₀ (all synthesized from the same precursor, squalene)
  • Steroids
  • Hopanoids
• Tetraterpenoids, C₄₀, which include carotenoids

Biomarker classification

• Lipids

• Acetogenic lipids

• Isoprenoids

• Acyclic and cyclic isoprenoids

• Polycyclic isoprenoids

• Hopanoids

• Steroids

• Carotenoids

• Squalene

• Kerogen

• Diagenesis and catagenesis

Biomarker as Source Indicator

• Steranes, hopanes

• Hydrocarbons

• Environmental Indicators

• Indicators of Euxinia

Experimental methods to extract biomarkers

• Source rock

• Extraction

• Fractionation

• GCMS