Linear quadrupole analyzer properties

The triple quadrupole mass spectrometer consists of a linear combination of three quadrupole mass analyzers. Figure 9.15 [2,56,111]. Only the first and third quadrupole have scan capability. The middle quadrupole, which is sometimes a multipole device of higher order, is a radio frequency-only, gas-filled collision cell with ion focusing properties. All ions above a certain threshold m/z value are transmitted by the middle quadrupole. An offset voltage between the ion source and collision cell can be adjusted to allow the collision energy to be varied between zero and about 200 eV. Inert gases (e.g. He, Ar, Xe) at a pressure of about 2-4 mTorr are commonly used as targets to... 

---