Patent ID: 8847155
Filing Date: 2014-09-30
Classification: H01J

Abstract:
1. A tandem time-of-flight mass spectrometer comprising: a. a first time-of-flight mass analyzer that performs a first TOF mass analysis by generating an ion beam comprising a plurality of ions and then selecting a group of precursor ions with predetermined mass-to-charge ratios from the plurality of ions, wherein an ion flight time of the selected group of precursor ions through the first time-of-flight mass analyzer is substantially independent to first order of both an initial position and an initial velocity; b. an ion fragmentation chamber positioned in the ion flight path of the selected group of precursor ions, the ion fragmentation chamber fragmenting at least one of the selected group of precursor ions accelerated by the ion accelerator; and c. a second time-of-flight mass analyzer positioned in the ion flight path of the selected group of precursor ions, the second time-of-flight mass analyzer performing a second TOF mass analysis by separating the ion fragments and then detecting a fragment ion mass spectrum with a detector, wherein a flight time of precursor ions and fragments thereof to the ion detector is dependent on a mass-to-charge ratio of the selected precursor ions and fragments thereof and is nearly independent of a velocity distribution of the selected precursor ions and fragments thereof.