This is a unique isotopically-resolved metabolite assignment methodology that we are patenting (US patent application 15/642,143).

We have developed and refined a novel algorithm SMIRFE that detects small biomolecules less than 2000 daltons in mass at a desired statistical confidence and determines their specific elemental molecular formula (EMF) using detected cliques of related isotopologue peaks with compatible isotope resolved molecular formulae (IMFs). The methodology works on both mass spectra derived from non-stable isotope tracing experiments, but especially on mass spectra from stable isotope tracing experiments. The current implementation efficiently searches a roughly 200 quintillion (2x1020) IMF space for each peak’s m/z, based on molecular masses <=2000 daltons, but larger IMF spaces are searchable.