17
Scan Types
Selected Reaction Monitoring Scan Type
Thermo Scientific
TSQ Altis, Quantis, and Fortis Hardware Manual
77
Figure 40.
Examples of compounds with a common fragment
Selected Reaction Monitoring Scan Type
Selected reaction monitoring (SRM) monitors a particular transition or set of transitions, such
as the fragmentation of an ion or the loss of a neutral moiety. SRM monitors a limited
number of precursor/product ion pairs.
As does SIM, SRM provides for the very rapid analysis of trace components in complex
mixtures. However, because SRM selects two sets of ions, it obtains greater selectivity
compared to SIM. Any interfering compound would have to form a precursor ion of the same
m/z
as the selected precursor ion from the target compound. Furthermore, that precursor ion
would have to fragment to form a product ion of the same
m/z
as the selected product ion
from the target compound.
N
N
N
N
N
O
H
N
N
N
N
N
2
H
N
2
H
N
N
N
2
H
N
2
H
