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US 9,177,776 B2Granted
Mass to charge ratio selective ejection from ion guide having supplemental RF voltage applied thereto
AssigneeMicromass UK Limited
InventorsJohn Brian Hoyes, Daniel James Kenny, David Langridge
Life of this patent
Estimating the term…
Abstract
An ion guide is disclosed wherein an axial DC voltage barrier is created at the exit of the ion guide. A primary RF voltage is applied to the electrodes in order to confine ions radially within the ion guide. A supplemental RF voltage is also applied to the electrodes. The supplemental RF voltage has a greater axial repeat length than that of the primary RF voltage. The amplitude of the supplemental RF voltage is increased with time causing ions to become unstable and gain sufficient axial kinetic energy such that the ions overcome the axial DC voltage barrier. Ions emerge axially from the ion guide in mass to charge ratio order.
Claims17
An ion guide comprising:
- a plurality of electrodes;
- a first device arranged and adapted to apply a first RF voltage to at least some of said electrodes;
- and
- a second device arranged and adapted to apply one or more DC voltages to one or more electrodes in order to maintain one or more axial DC voltage barriers at one or more positions along the ion guide so as to confine at least some ions axially within said ion guide;
- wherein said ion guide further comprises:
- a third device arranged and adapted to apply a second RF voltage to at least some of said electrodes, wherein two or more axially adjacent electrodes are maintained at a same first RF phase of said second RF voltage and two or more subsequent axially adjacent electrodes are maintained at a same second RF phase of said second RF voltage, said first RF phase of said second RF voltage being different from or opposite to said second RF phase of said second RF voltage;
- and
- a fourth device arranged and adapted to progressively increase, linearly increase, or increase in a stepped or other manner an amplitude, height or depth or frequency of either said first RF voltage or said second RF voltage such that at least some of said ions overcome said one or more axial DC voltage barriers and emerge axially from said ion guide.
5 more elements
A method of guiding ions comprising:
- providing an ion guide comprising a plurality of electrodes;
- applying a first RF voltage to at least some of said electrodes;
- and
- applying one or more DC voltages to one or more electrodes in order to maintain one or more axial DC voltage barriers at one or more positions along the ion guide so as to confine at least some ions axially within said ion guide;
- wherein said method further comprises:
- applying a second RF voltage to at least some of said electrodes, wherein two or more axially adjacent electrodes are maintained at a same first RF phase of said second RF voltage and two or more subsequent axially adjacent electrodes are maintained at a same second RF phase of said second RF voltage, said first RF phase of said second RF voltage being different from or opposite to said second RF phase of said second RF voltage;
- and
- progressively increasing, linearly increasing, or increasing in a stepped or other manner an amplitude, height or depth or frequency of either said first RF voltage or said second RF voltage such that at least some of said ions overcome said one or more axial DC voltage barriers and emerge axially from said ion guide.
5 more elements
A mass analyser comprising:
- a plurality of electrodes;
- a device arranged and adapted to apply a primary RF voltage and a supplemental RF voltage to at least some of said electrodes, wherein said supplemental RF voltage is applied to the electrodes with an axial repeat unit, pattern or length which is greater than that of the primary RF voltage;
- a device arranged and adapted to maintain an axial DC voltage barrier at a position along the mass analyser;
- and
- a device arranged and adapted to progressively increase an amplitude of the supplemental RF voltage so as to cause ions progressively to overcome said axial voltage barrier.
2 more elements
A method of mass analysing ions comprising:
- providing a mass analyser comprising a plurality of electrodes;
- applying a primary RF voltage and a supplemental RF voltage to at least some of said electrodes, wherein said supplemental RF voltage is applied to the electrodes with an axial repeat unit, pattern or length which is greater than that of the primary RF voltage;
- maintaining an axial DC voltage barrier at a position along the mass analyser;
- and
- progressively increasing an amplitude of the supplemental RF voltage so as to cause ions progressively to overcome said axial voltage barrier.
2 more elements
Dependencies are inferred from the claim text.