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1.6.2
Precursor ion mode
Figure 1–5:
1.6.2.1
Typical application
You typically use the precursor, or parent, 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.
1.6.3
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. The
sensitivity of MRM mode therefore exceeds that of scanning-mode MS/MS. MRM allows isolation
of the compound of interest from the chemical background noise and is the most frequently used
acquisition mode for quantitative analysis.
Figure 1–6:
1.6.4
PICS mode
A variation on MRM, PICS provides you the means to collect a product ion spectrum from the top
of all detected peaks in MRM mode. Thus it enables additional confidence in your peak
assignment.
1.6.5
RADAR
In RADAR mode, the Xevo TQD IVD rapidly alternates between MRM and full-scan MS acquisition
modes. The instrument tracks target analytes with precision in MRM mode. At the same time, it
Precursor ion mode
MS1
Scanning
Multiple reaction monitoring mode
MS1
Static (at precursor mass)
September 7, 2016, 715003560IVD Rev. C
Collision cell
Fragmenting precursor
ions and passing all
masses
Collision cell
Fragmenting precursor
ions and passing all
masses
Page 27
MS2
Static (at product mass)
MS2
Static (at product mass)
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