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. Author manuscript; available in PMC: 2012 Oct 1.
Published in final edited form as: J Am Soc Mass Spectrom. 2011 Jul 9;22(10):1784–1793. doi: 10.1007/s13361-011-0196-7

Figure 4.

Figure 4

Hydrogen scrambling during ETD can be minimized to negligible levels in quadruply protonated peptides by tuning the Z-spray ion source. Deuterium contents (red curves) of c-type fragment ions of labeled quadruply protonated peptide P1 upon ETD at defined “mild” ion source conditions (upper panel) and after a moderate increase of the sample cone (45 V) and extraction cone (4.1 V) voltages (lower panel). The theoretical values in case of 0% (dotted green line) and 100% (dotted blue line) hydrogen scrambling are indicated.