Gas chromatograph-combustion-isotope ratio mass spectrometer (GC-C-IRMS; Finnigan Delta XP IRMS coupled with a Trace GC and Interface III). This set of instruments allow us to conduct stable isotope analysis of carbon and hydrogen isotope compositions for many types of compounds, e.g. n-alkanes, hopanes and fatty acids. In our lab, this instrument typically runs for compound-specific carbon isotope analysis. These compound-specific carbon isotope data can be used to reconstruct the evolution history of C3/C4 plants, and to track the metabolic processes of ancient microbes recorded in geological sediments.