MASS SPECTROMETER

摘要

A closed-loop ion guide (1) is disclosed comprising a plurality of electrodes having apertures through which ions are transmitted in use. Ions are injected into the closed- loop ion guide (1) and may make several circuits of the closed- loop ion guide (1) before being ejected from the ion guide (1). In a mode of operation the ion guide (1) may be arranged to separate ions temporally according to their ion mobility.