Figure 2. mzGroupAnalyzer is able to detect possible metabolic steps out of various proposed sum formulas for a measured m/z feature.

A Kaempferol and Quercetin standards measured by LC-MS result into several sum formula suggestions for the measured mass-to-charge-ratio (m/z). Because a low ppm deviation of assigned elemental composition to the mass is not the decisive factor, the correct sum formula might not be the first one proposed and thus several must be looked at, which is handled by the program automatically. If mzGroupAnalyzer finds a possible reaction step (out of a list of reactions which can be altered manually), it is reported to the user. B MS² spectra of Kaempferol (left) and Quercetin (right). The fragmentation schemes are in accordance with published literature [42], [43]. The difference of one oxygen atom (nominal mass 16) is visible in the fragments m/z 213→229 and 241→257, while m/z 165 occurs in both product scans.