Mass spectrometry with segmented RF multiple ion guides in various pressure regions
First Claim
1. An apparatus for analyzing chemical species, comprising:
- an ion source for operation at substantially atmospheric pressure to produce ions from a sample substance;
at least one vacuum stage having means for pumping away gas to produce a partial vacuum;
means for delivering said ions from said ion source into one of said at least one vacuum stage;
a collision cell configured in at least one of said at least one vacuum stage such that said ions may be directed into said collision cell, wherein said collision cell comprises at least one higher neutral gas pressure region, in which the neutral gas is controllably elevated to be higher than in other vacuum regions proximal to said collision cell, such that collisions between said ions and neutral gas molecules occur within said higher neutral gas pressure region while such collisions essentially do not occur within other vacuum regions proximal to said collision cell;
a detector configured in one of said at least one vacuum stage;
at least two multipole ion guide segments, each of said multipole ion guide segments having a plurality of poles, wherein at least a portion of each of said at least two multipole ion guide segments is positioned within said collision cell; and
independent RF frequency and DC voltage sources applied to each of said at least two multipole ion guide segments, wherein said RF frequency and DC voltages applied to each of said at least two multipole ion guide segments are controlled independently of each other.
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Abstract
A mass spectrometer is configured with individual multipole ion guides, configured in an assembly in alignment along a common centerline wherein at least a portion of at least one multipole ion guide mounted in the assembly resides in a vacuum region with higher background pressure, and the other portion resides in a vacuum region with lower background pressure. Said multipole ion guides are operated in mass to charge selection and ion fragmentation modes, in either a high or low pressure region, said region being selected according to the optimum pressure or pressure gradient for the function performed. The diameter, lengths and applied frequencies and phases on these contiguous ion guides may be the same or may differ. A variety of MS and MS/MSn analysis functions can be achieved using a series of contiguous multipole ion guides operating in either higher background vacuum pressures, or along pressure gradients in the region where the pressure drops from high to low pressure, or in low pressure regions. Individual sets of RF, +/−DC and resonant frequency waveform voltage supplies provide potentials to the rods of each multipole ion guide allowing the operation of ion transmission, ion trapping, mass to charge selection and ion fragmentation functions independently in each ion guide. The presence of background pressure maintained sufficiently high to cause ion to neutral gas collisions along a portion of each multiple ion guide linear assembly allows the conducting of Collisional Induced Dissociation (CID) fragmentation of ions by axially accelerating ions from one multipole ion guide into an adjacent ion guide. Alternatively ions can be fragmented in one or more multipole ion guides using resonant frequency excitation CID. A multiple multipole ion guide assembly can be configured as the primary mass analyzer in single or triple quadrupole mass analyzers with or without mass selective axial ejection. Alternatively, the multiple multipole ion guide linear assembly can be configured as part of a hybrid Time-Of-Flight, Magnetic Sector, Ion Trap or Fourier Transform mass analyzer.
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Citations
29 Claims
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1. An apparatus for analyzing chemical species, comprising:
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an ion source for operation at substantially atmospheric pressure to produce ions from a sample substance; at least one vacuum stage having means for pumping away gas to produce a partial vacuum; means for delivering said ions from said ion source into one of said at least one vacuum stage; a collision cell configured in at least one of said at least one vacuum stage such that said ions may be directed into said collision cell, wherein said collision cell comprises at least one higher neutral gas pressure region, in which the neutral gas is controllably elevated to be higher than in other vacuum regions proximal to said collision cell, such that collisions between said ions and neutral gas molecules occur within said higher neutral gas pressure region while such collisions essentially do not occur within other vacuum regions proximal to said collision cell; a detector configured in one of said at least one vacuum stage; at least two multipole ion guide segments, each of said multipole ion guide segments having a plurality of poles, wherein at least a portion of each of said at least two multipole ion guide segments is positioned within said collision cell; and independent RF frequency and DC voltage sources applied to each of said at least two multipole ion guide segments, wherein said RF frequency and DC voltages applied to each of said at least two multipole ion guide segments are controlled independently of each other. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification
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- Resources
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Current AssigneePerkin Elmer Life Sciences
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Original AssigneeANALYTICA OF BRANFORD, INC. (Revvity, Inc.)
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InventorsWhitehouse, Craig M., Cousins, Lisa, Javahery, Gholamreza, Welkie, David G.
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Primary Examiner(s)Lee, John R.
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Assistant Examiner(s)Fernandez, Kalimah
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Application NumberUS10/448,495Time in Patent Office1,061 DaysField of Search250/287, 250/289, 250/288, 250/281, 250/282US Class Current250/289CPC Class CodesH01J 49/004 Combinations of spectromete...H01J 49/063 Multipole ion guides, e.g. ...H01J 49/4225 Multipole linear ion traps,...
