Ion funnel with extended mass range and reduced conductance limit aperture
AssigneeBattelle Memorial Institute
InventorsAleksey V. Tolmachev, Richard D. Smith
Life of this patent
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Abstract
An improved ion funnel design is disclosed that decreases the axial RF (parasite) fields at the ion funnel exit. This is achieved by addition of one or more compensation electrodes after the conductance limit electrode. Various RF voltage profiles may be applied to the various electrodes minimizing the parasite axial potential wells. The smallest RF aperture that serves as the conductance limiting electrode is further reduced over standard designs. Overall, the ion funnel improves transmission ranges of both low m/z and high m/z ions, reducing RF activation of ions and decreasing the gas load to subsequent differential pumping stages.
Claims17
A modified ion funnel that extends the m/z range and the efficiency of transmission of ions in mass spectrometry analysis, comprising:
- an ion funnel having one or more electrodes disposed in succession with a terminal electrode disposed immediately following said one or more electrodes with co-axially aligned apertures, said terminal electrode having an aperture smaller than any electrode preceding it in said ion funnel;
- a conductance limiting electrode co-axially aligned with, and disposed immediately following, said terminal electrode of said ion funnel, said conductance limiting electrode defining an aperture that is smaller than any other aperture of said ion funnel;
- at least one compensation electrode co-axially aligned with, and disposed immediately following, said conductance limiting electrode, said at least one compensation electrode defining an aperture that is larger than the aperture of said conductance limiting electrode, wherein said at least one compensation electrode generates an electric potential adapted to deliver preselected on-axis and off-axis potential distributions at apertures of said one or more electrodes, said terminal electrode, said conductance limiting electrode, and/or said at least one compensation electrode;
- and
- whereby said preselected potential distributions extend the m/z range, the operational pressure range, and/or the efficiency of transmission of ions to a subsequent differential pumping stage or to a mass spectrometer.
Dependencies are inferred from the claim text.