Selective ion mobility spectrometer formed from two consecutive mass selective filters
AssigneeBruker Daltonik GmbH
InventorsMelvin Andrew Park, Desmond Allen Kaplan, Mark Ridgeway
Life of this patent
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Abstract
Ions with a predetermined range of ion mobilities are produced by filtering input ions with at least two consecutive ion mobility high pass and/or low pass filters. Each ion mobility filter is formed by entraining ions in a moving gas and applying a DC electric field to the ions which causes the ions to move in a direction opposite to the gas flow. An ion mobility high pass filter is formed when the DC electric field drives the ions against the flow of gas, whereas an ion mobility low pass filter is formed when a the gas flow drives entrained ions against an DC electric field barrier.
Claims11
A method for the collection of ions of a predetermined ion mobility range μ1>μ>μ2, comprising:
- (a) passing ions from an ion source to two consecutive ion mobility low pass filters, a first filter followed by a second filter downstream from the first filter, each filter formed by entraining ions in a gas flowing away from the ion source and driving the entrained ions against a DC electric field barrier of predetermined, the first filter comprising a first DC electric field barrier blocking the passage of ions with a mobility of μ≧μ1 and the second filter comprising a second DC electric field barrier blocking the passage of ions with a mobility of μ≧μ2, where μ2<μ1, wherein the DC electric field barrier of the first filter and the DC electric field barrier of the second filter are each stationary along an axis parallel to the direction of the flow of the gas;
- and (b) collecting ions from the ion source in said predetermined ion mobility range in a space between the two filters.
A method for the collection of ions of a predetermined ion mobility range μ1>μ>μ2 comprising:
- (a) passing ions from an ion source to first and second ion mobility high pass filters, the filters being formed by a gas flowing toward the ion source and DC electric fields driving the ions in a direction opposite the gas flow, the first ion mobility high pass filter providing a DC electric field that transports ions from the ions source having a mobility of μ≧μ1 forward against a counteracting force of the gas, and the second ion mobility high pass filter providing a DC electric field that transports ions received from the first ion mobility high pass filter having a mobility of μ≧μ2 forward against a counteracting force of the gas, where μ2>μ1, wherein the DC electric field of the first filter and the DC electric field of the second filter are each stationary along an axis parallel to the direction of the flow of the gas;
- and (b) collecting ions in said predetermined ion mobility range in a space between the two filters.
Dependencies are inferred from the claim text.