Ranking of structural formulas

2 Ranking of structural formulas Calculation of match values for structural formulas 

As mentioned earlier, fragmentation in a mass spectrometer generally follows known reaction schemes. We will use this knowledge during calculation of a match value for structure candidate M with respect to experimental mass spectrum I. The calculation is similar to that for molecular formula candidates. However, in the case of structural formulas we can considerably restrict the set of possible fragment molecular formulas jSj. We will consider only such molecular formulas for which fragments exist that are derived from M by successive ionization and fragmentation reactions. To simulate these we go back to the previous work in Section 2.3. 

In Subsection 2.2.1 we introduced several atom types to assist in the definition of reaction schemes in mass spectrometry. We use these atom types to represent various sets of elements  

Z all elements with floe electron pairs (N, 0, P, S, halogens) 

Reactions in a mass spectrometer are divided into three classes, ionization, fragmentation, and reeirreuigement reactions. Ionization in the mass spectrometer converts a molecule without cheirge or unpaired electron into a positively charged ion with an unpaired electron, a cation radical. Ionization steps take place exclusively at the beginning of a fragmentation path. We use these ionization reactions  

---

See also in sourсe #XX -- [ ]

---