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. Author manuscript; available in PMC: 2009 Jul 15.
Published in final edited form as: Anal Chem. 2008 Jun 20;80(14):5596–5606. doi: 10.1021/ac8006076

Figure 3.

Figure 3

The intensity of the base-peak-normalized immonium ion peaks plotted against the percentage of the population that contains the residue of interest for doubly-charged ions. The base-peak-normalized intensity of the immonium ion is grouped in five quintiles plus a zero value on the x-axis. The percentage of the population having the residue of interest is given on the y-axis. The horizontal line represents the proportion of sequences in the database (800−1900 Da) containing the residue. Each chart represents a single amino acid as indicated at the top; W cor indicates a plot corrected for confounding peaks.