The OrbiTOF mass analyzer: Time-of-flight analysis via an orbitrap quadro-logarithmic field with periodic drift focusing

Abstract

Thermo Scientific™ Orbitrap™ analyzers represent a prominent class of high-resolution mass analyzer commonly used in life sciences, and for interrogation of complex samples. Injected ions, trapped within a quadro-logarithmic field, orbit a central electrode and oscillate up and down the axis. A new class of multi-reflection time-of-flight mass analyzer has been developed based on the Orbitrap field structure plus an additional series of periodic lenses wrapped around the central axis to constrain beam dispersion. The axial and angular velocity of the injected ions was balanced so that with each axial oscillation, the ions passed through the next lens in the series, to form a tightly folded 25-m long, 3-dimensional ion path, ending with ions striking a detector surface.

Performance was interrogated via experiment and simulation. 70k resolving power was observed within the relatively compact analyzer, albeit at cost to transmission. A larger design with an integrated extraction trap and greater flight energy is discussed.