
Chapter 7 PSD Analysis
7-40 PerSeptive Biosystems
7
7.4.2 Observing the Effects
of Precursor Ion Selector
Turning on the Precursor Ion Selector eliminates prompt
fragments in a spectrum.
In this section
In this section, you will:
• Turn off the Precursor Ion Selector (called Timed Ion
Selector in Reflector mode) and observe the spectrum
• Distinguish between the two types of fragments, prompt
and PSD
• Understand the impact of the Precursor Ion Selector on
prompt fragments
Turning off
Precursor Ion
Selector
To observe the effects of the Precursor Ion Selector (called
Timed Ion Selector in Reflector mode):
1. In the PSD Acquisition Settings control page, deselect
Precursor Ion Selector.
2. Acquire a spectrum.
3. Observe the 1,180 to 1,190 Da mass region. Note the
additional peaks that appear below 1,185 Da when the
Precursor Ion Selector is turned off (Figure 7-11).
Figure 7-11 Angiotensin I Fragment Ions (Precursor Ion Selector Off)
Additional peaks appear when
Precursor Ion Selector is turned off
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