Enrichment Fraction

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Found in the PeakGroups data format.

A weighted average of the fraction of labeled atoms (e.g. Carbons, Nitrogens, Oxygens, etc.) across all peaks in a PeakGroup detected in a particular sample. E.g. The fraction of labeled carbons in lysine detected in a spleen sample.

\[ L_{avg} = \frac{\sum_i^M i\, L_{i} }{M} \]

Where:

  • \(i\) is the number of labeled atoms (i.e. isotopes) of a particular element in any one peak.
  • \(L_i\) is the fractional abundance of the massisomer peak see Fraction
  • \(M\) is the total number of atoms of a particular element in any one compound (labeled or not).

See the Enrichment Fraction column of the PeakGroup table in this Enrichment Example.