Method of extracting ions with a low M/Z ratio from an ion trap
AssigneeDH Technologies Development Pte. Ltd.
InventorTakashi Baba
Life of this patent
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Abstract
In a mass spectrometer, a method for trapping ions includes providing at least first and second multipole rod sets positioned in tandem, introducing a plurality of ions into the first rod set, applying an RF potential to at least one of said rod sets to generate a radial trapping potential within said rod sets, applying a radial DC potential to said first rod set so as to modulate said radial trapping potential set as a function of m/z of said ions, and applying a DC potential between said two rod sets to provide an axial bias potential between said two rod sets. The method can further comprise selecting an axial barrier potential to selectively extract ions having an m/z ratio less than a threshold from said first rod set into said second rod set.
Claims14
A method for trapping ions in a mass spectrometer, comprising:
- providing at least first and second multipole rod sets positioned in tandem,
- applying a radial RF potential to at least one of said rod sets to generate an RF radial trapping potential within at least said first rod set,
- applying a radial dipolar DC potential to said first rod set so as to modulate said radial trapping potential as a function of m/z of said ions,
- applying an axial bias DC potential between said two rod sets to provide an axial bias potential between said two rod sets, and
- introducing a plurality of ions into said first rod set.
A mass spectrometer, comprising:
- an ion trap comprising at least one multipole rod set configured to trap a plurality of ions via a radial RF field and a radial dipolar DC field within said first rod set,
- a first voltage source for applying the radial RF potential to at least one of said rod sets to generate an RF radial trapping potential within at least said first rod set,
- a second voltage source for applying the radial dipolar DC potential to said first rod set so as to modulate said radial trapping potential as a function of m/z of said ions, and
- a third voltage source for applying an axial bias DC potential between said two rod sets to provide an axial bias potential between said two rod sets.
Dependencies are inferred from the claim text.