Ion Detection and Resolving Power of the Orbitrap

In an orbitrap, the mass resolving power R is half the frequency resolving power due to the square root in Eq. 4.45 [210,214]. It can be calculated as 

Note While the frequency of the axial oscillation coz in an orbitrap is proportional to iqlm, the cyclotron ftequency in FT-ICR is proportional to q/m. As a consequence, FT-ICR offers better resolving power for lower m/z ions whereas the orbitrap may outperform it at high m/z values, e.g., above m/z 800 in case of an FT-ICR instrument with a 7-T magnet [206,210]. 

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