Mass-Analyzing Linear Ion Trap with Radial Ejection

3 Mass-Analyzing Linear Ion Trap with Radial Ejection 

A scanning LIT [109] can alternatively be realized using a mass-selective radial ejection noode of operation. Such a LIT can either serve as a stand-alone mass analyzer (Thermo Sdentific LTQ series) or can be combined into a hybrid LIT-FT- 

ICR instrument (Thermo Scientific LTQ-FT series). In the LTQ-FT instruments, the LIT shields the ultrahigh vacuum of the FT-ICR from collision gas and decomposition products in order to operate under optimum conditions. More importantly from the analytical point of view, the LIT can accumulate, mass-select and fragment selected ions prior to the next FT-ICR cycle while the ICR cell is still busy with the previous ion package (FT-ICR cf. Chap. 4.7). By using an orbi-trap analyzer (Chap. 4.8) in place of the FT-ICR cell, the same company offers the Thermo Scientific LTQ-Orbitrap series as an economical nonetheless powerful alternative to their LTQ-FT. 

Note It takes more than just a nicely working m/z analyzer to put together a real-world instrument. Thus, the example in the next short paragraph presents a typical technical approach relevant for any type of mass spectrometer. 

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