A triple quadrupole mass spectrometer is a tandem mass spectrometer consisting of two quadrupole mass spectrometers in series, with a (non mass-resolving) radio frequency (RF) only quadrupole between them to act as a collision cell for collision-induced dissociation. The first (Q1) and third (Q3) quadrupoles serve as mass filters, whereas the middle (q2) quadrupole serves as a collision cell. This collision cell is an RF only quadrupole (non-mass filtering) using an inert gas such as Ar, He or N2 gas to provide collision-induced dissociation of a selected precursor ion that is selected in Q1. Subsequent fragments are passed through to Q3 where they may be filtered or scanned.
== Structural mass spectrometry ==
This alignment of two mass spectrometers in succession with a collision cell (e.g. a collision quadrupole) in between allows structural mass spectrometry to be performed. For example, the Q1 may be set to select an ion of a known mass, which is fragmented in q2. The third quadrupole (Q3) is then set to scan the entire m/z range, giving information on the sizes of the fragments made. From the ion fragmentation information, the structure of the original ion can be deduced.
== History ==
The arrangement of three quadrupoles was first developed by Morrizon of LaTrobe University, Australia for the purpose of studying the photodissociation of gas-phase ions. The first triple-quadrupole mass spectrometer was developed at Michigan State University by Enke and Yost in the late 1970's.
== References ==