Precursor (Parent) Ion Mode; Multiple Reaction Monitoring Mode - Waters Xevo TQD Overview And Maintenance Manual

1 Specifications and Operating Modes

Precursor (parent) ion mode

Precursor ion mode:
Typical application
You typically use the precursor ion mode for structural elucidation—that is, to
complement or confirm product scan data—by scanning for all the precursors
of a common product ion.

Multiple reaction monitoring mode

Multiple reaction monitoring (MRM) mode is the highly selective MS/MS
equivalent of SIR. Because both MS1 and MS2 are static, greater dwell time
on the ions of interest is possible, so the sensitivity achieved is better,
compared with scanning-mode MS/MS. This mode is the most commonly used
acquisition mode for quantitative analysis, allowing the compound of interest
to be isolated from the chemical background noise.
Multiple reaction monitoring mode:
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MS1
Scanning
MS1
Static (at precursor mass)
Collision cell
Fragmenting
precursor ions and
passing all masses
Collision cell
Fragmenting
precursor ions and
passing all masses
MS2
Static (at product mass)
MS2
Static (at product mass)