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Introduction
Scan Modes
Thermo Scientific TSQ Quantum XLS Series User Guide 9
Figure 4. Illustration of the Parent scan mode
You can perform experiments that use the parent scan mode (parent experiments) in structure
and fragmentation studies as well as in survey analyses of mixtures. In general, parent
experiments detect all compounds that decompose to a common fragment. The experiments
are useful for the rapid detection of a series of structural homologs that have a common
fragment ion (for example, m/z 149 for the phthalates).
Neutral Loss Scan Modes
The Neutral Loss scan mode links the two mass analyzers (Q1 and Q3) together so that they
are scanned at the same rate over mass ranges of the same width. The respective mass ranges,
however, are offset by a selected mass so that the product mass analyzer scans a selected
number of mass units lower than the parent mass analyzer.
As a result, the Neutral Loss scan mode has two stages of mass analysis. In the first stage, the
parent mass analyzer separates ions formed in the ion source by mass-to-charge ratio. Then
the ions are introduced sequentially into the collision cell.
In the second stage of analysis, ions admitted to the collision cell can fragment further by
metastable ion decomposition or by CID to produce product ions. The product mass analyzer
then separates these product ions by mass-to-charge ratio. Figure 5 illustrates the Neutral Loss
scan mode. Examples of compounds with a common neutral loss fragment appear in Figure 6
on page 11.
Q1
m/z
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