Duty cycle enhancement of an orthogonal acceleration TOF mass spectrometer using an axially-resonant excitation linear ion trap.

We report a new technique to enhance detection duty cycle of an orthogonal-acceleration time-of-flight mass spectrometer (oaTOF) over a broad mass range. To this end, we used an axially-resonant-excitation linear ion trap, which ejects ions axially and mass selectively into a non-mass-selective linear ion trap in front of the TOF pusher. A delay between the ejection timing of the non-mass-selective LIT and the push timing of the oaTOF was swept mass-synchronously with the axially-resonant-excitation linear ion trap, so that ions are detected with duty cycle larger than 60% over a wide mass range from m/z 174.1 to 1922.0, which is 3 to 10 times better than conventional oaTOF.