We note that widely applied biomarker parameters are in part constrained by commonly available GC-MS analytical techniques that favor small polycyclic hydrocarbons due to their distinctive and information-rich mass spectra, low analytical detection limits, and occurrence in selective MSxMS transitions. For many other geochemical analyses, standard GC-MS techniques fall short because: 1) molecular ions are too weak, 2) distinctive fragment ions are only subtly elevated, 3) overall sensitivity is suppressed by extensive fragmentation to small generic hydrocarbon ions, and/or 4) temperatures required for volatilizing higher molecular weight compounds are incompatible with common column phase and compound stability. It is expected that GC-MS with SMB will enable the analysis of many new or underutilized molecular fossils at low concentrations, allowing measurement and recognition of source specific signatures in a greater diversity of samples.
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