Patent ID: 9607820
Date: 2017-03-28
CPC Classifications: G01N,H01J

Claim:
1. A mass spectrometer comprising: an ion mobility spectrometer comprising a drift tube, said ion mobility spectrometer being configured to temporally separate ions according to their ion mobility to form temporally separated ions; one or more ion-optical devices and an ion trapping device arranged upstream of said ion mobility spectrometer; a first fragmentation, collision or reaction device that produces product ions from parent ions and is arranged downstream of said ion mobility spectrometer; and a voltage source configured in a first mode of operation to progressively vary or scan or step a potential difference between said ion mobility spectrometer and said first fragmentation, collision or reaction device based on the time at which ions are admitted into said ion mobility spectrometer such that the temporally separated ions pass through a substantially optimum potential difference for fragmentation as the temporally separated ions enter said first fragmentation, collision or reaction device, whilst maintaining each of said one or more ion-optical devices and the ion trapping device at a respective substantially constant potential.