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Scan Parameters
Scan Types
Thermo Scientific TSQ Endura and TSQ Quantiva Hardware Manual 17
Precursor Scan Type
The precursor scan type also uses two stages of analysis. In the first stage, the ion source forms
ions that are introduced into the precursor mass analyzer, which is scanned to transmit
precursor ions sequentially into the collision cell.
In the second stage of analysis, in the collision cell, precursor ions can fragment to produce
product ions by unimolecular decomposition of metastable ions or by CID. The collision cell
forms ions that enter the product mass analyzer, which transmits a selected product ion. (The
product set mass is the mass-to-charge ratio of ions transmitted by the product mass analyzer.)
The resulting spectrum shows all the precursor ions that fragment to produce the selected
product ion. For a mass spectrum obtained in the precursor scan type (precursor mass
spectrum), note that data for the mass-to-charge ratio axis is obtained from Q1 (the precursor
ions), whereas data for the ion intensity axis is obtained from Q3 (from monitoring the
product ion).
Figure 6 illustrates the precursor scan type.
Figure 6. Illustration of the precursor scan type
You can use experiments that employ the precursor scan type (precursor experiments) in
structure and fragmentation studies as well as in survey analyses of mixtures. In general,
precursor experiments detect all compounds that decompose to a common fragment. You can
use the experiments for the rapid detection of a series of structural homologs (for example,
substituted aromatics, phthalates, steroids, or fatty acids) that have a common fragment ion
(for example, m/z 149 for the phthalates).
Q2
RF Only + Ar
Q1 Scanning Q3 Set
Q1 m/z
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