Mass-Analyzing Linear Quadrupole Ion Trap with Axial Ejection

2 Mass-Analyzing Linear Quadrupole Ion Trap with Axial Ejection 

As with the linear quadrupole before, the potential (x,y.z,t) in the two-dimensional quadrupole field of the LIT is expressed by a DC voltage U and an RF drive voltage V with the frequency Q. ([108,118] and Chap. 5 in [ 119]) 

In practice, there is no DC conponent, and thus, only the Mathieu parameter q is required, which is obtained by solving the above equations 

The voltage V is the zero-to-peak anplitude of the RF drive voltage. For an ion inside the quadrupole field the fundamental resonant frequency con is obtained as 

Note The QqLIT setup combines into one single instrument different kinds of mass analyzers, a scanning linear quadrupole, and a scanning linear quadrupole ion trap all connected via an RF-only ion guide. Instmments combining different types of mass analyzers are termed hybrid instruments. Most modem mass spectrometers are assembled from different elements to achieve optimum capabilities in the sense of creating instmments uniting the best of two worlds [114]. An overview of hybrids is presented at the end of the analyzer section. 

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