Waters Xevo TQ MS, Operator And Maintenance Manual, Page: 29 / 184

MS/MS operating modes 1-13
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 a highly selective MS/MS
equivalent of SIR. Because both MS1 and MS2 are static, greater dwell time
on the ions of interest is possible and 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
MS1
Scanning
MS2
Static (at product mass)
Collision cell
Pass all masses
MS1
Static (at precursor mass)
MS2
Static (at product mass)
Collision cell
Pass all masses