Mass Spectrometry in Systems Biology - Systems Biology: Networks, Models, and Applications - page 7

Figure 1.2 Schematic diagram of multistage mass spectrometers built from
different type of mass analyzers. (a) Triple quadrupole. (b) Q-TOF. (Reprinted,
with permission, from the Annual Review of Biophysics and Biomolecular
Structure, vol. 33, © 2004 Annual Reviews, www.annualreviews.org.)
both the precursor ion and the production of one fragment ion (multiple
ion reaction monitoring). Triple quadrupoles are often used in
metabolomics.
A quadruople-time-of-flight (Q-TOF) (figure 1.2b) uses the configu-
ration of triple quadrupole in which the third segment is a TOF
analyzer rather than a quadrupole, therefore increasing both resolution
and mass accuracy [12]. In a quadrupole linear ion trap (figure 1.2c),
the TOF analyzer is replaced by a linear ion trap [13]. Sequencing
experiments (MS/MS) take place in the linear ion trap. This instrument
combines selectivity of the quadrupole mass filter with high-sensitivity
analysis by the linear ion trap.