User`s guide

Chapter 7 PSD Analysis
7-12 PerSeptive Biosystems
7
Benefits The benefits provided by CID include:
• Fragmentation of ions that does not occur under normal
PSD conditions
• Side chain fragmentation that may allow you to
distinguish between Leucine and Isoleucine isomers
• Greater number of immonium ions generated for peptide
analysis
Figure 7-6 and Figure 7-7 are sample spectra from low and
mid mass ranges that illustrate the impact of CID gas.
Figure 7-6 Low Masses—Impact of CID (Angiotensin I)
In the top trace (CID off), typical fragments are seen and
labeled.
In the bottom trace (CID on), fragments not seen without CID,
or fragments that are significantly enhanced with CID, are
labeled.
CID off
CID on, enhanced peaks
labeled