Fragment Tree Reconciliation (FTR) for Space Applications

Mass spectrometry (MS) is a powerful tool for composition and structure elucidation in analytical chemistry. Space missions commonly equip mass spectrometers to analyze atmospheric composition and to prove the existence/absence of organic molecules. Fragmentation trees, representing the stepwise cleavage of a measured sample to its ions, help in the assignment of molecular sum formulas and structures to measured peaks. We describe a recursive algorithm able to find congruent structures of a given fragmentation tree in a database agnostic fashion. By employing graph theoretical mappings and thermodynamic properties, we were able to consistently annotate single first-fragmentations of measured amino acid samples and also demonstrate reconciliation of full structures given correct fragmentation trees. While the current implementation is still plagued by implementation limits of integrated software, we highlight a clear way forward towards general applicability of our mathematical framework.