摘要 |
A mass spectrometer system and a method of operating a mass spectrometer having an elongated rod set, the rod set having an entrance end, an exit end, a plurality of rods and a longitudinal axis, involving (a) admitting ions into the entrance end of the rod set; (b) producing an RF field between the plurality of rods to radially confine the ions in the rod set; (c) providing a static axial electric field within the rod set; and (d) separating the ions into a first group of ions and a second group of ions by providing an oscillating axial electric field within the rod set to counteract the static axial electric field, wherein the oscillating axial electric field varies along the longitudinal axis of the rod se.
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