# US 10,319,577 B2 · Combined mass-to-charge ratio and charge state selection in tandem mass spectrometry > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,319,577 B2 - Document ID: US10319577B2 - Status: Granted - Kind: B2 - Application number: 15/626,447 - Filed: 2017-06-19 - Published: 2017-10-05 - Granted: 2019-06-11 - Earliest claimed: 2006-11-15 - Assignees: Micromass UK Limited - Applicants: Micromass UK Limited - Inventors: Robert Harold Bateman; Kevin Giles; Steven Derek Pringle; Jason Lee Wildgoose - Web page: https://patentgrep.com/patent/US10319577B2 ## CPC - H01J 49/4215: {Quadrupole mass filters (H01J49/4225 takes precedence)} - G01N 27/622: Ion mobility spectrometry - H01J 49/004: {Combinations of spectrometers, tandem spectrometers, e.g. MS/MS, MSn} - H01J 49/426: {Methods for controlling ions} - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A mass spectrometer is disclosed comprising an ion mobility spectrometer and an ion gate. A collision cell is arranged downstream of the ion gate. The operation of the ion mobility spectrometer and the ion gate are synchronized so that only ions having a particular mass to charge ration and a desired charge state are onwardly transmitted to the collision cell. ## Claims ### Claim 1 A mass spectrometer comprising: a first mass to charge ratio filter or mass to charge ratio mass analyser arranged and adapted in a first mode of operation to transmit ions having a mass to charge ratio within a first range; an ion mobility spectrometer or separator adapted in a mode of operation to separate ions according to ion mobility such that ions having substantially the same mass to charge ratio within the first range will exit the ion mobility spectrometer or separator at substantially different times; and attenuation means for attenuating ions in a mode of operation; wherein said attenuation means is configured such that it is not mass-selective and such that it either substantially allows all ions to be onwardly transmitted, or substantially attenuates all ions by preventing all ions from being transmitted; wherein said attenuation means comprises at least one of: an ion gate or ion barrier arranged downstream of said ion mobility spectrometer or separator; means for removing, attenuating or reducing the amplitude of an AC or RF voltage or potential which is applied to at least a portion of said ion mobility spectrometer or separator; and means for removing, attenuating or reducing the amplitude of an AC or RF voltage or potential which is applied to at least a portion of an ion guide or other ion optical device arranged downstream of said ion mobility spectrometer or separator; the mass spectrometer further comprising a control device configured to control the operation of said attenuation means; wherein said control device is configured to control the operation of said attenuation means so that said attenuation means operates to transmit substantially all ions during a first time period or first time window, and said attenuation means operates to attenuate substantially all ions during a second time period or second time window, wherein said second time period or second time window is different from said first time period or first time window, wherein said second time period or second time window is selected such that operation of the attenuation means to attenuate substantially all ions during said second time period or second time window causes ions having mass to charge ratios within said first range but having one or more undesired first charge states to be attenuated. ### Claim 2 (depends on 1) A mass spectrometer as claimed in claim 1, further comprising a collision, fragmentation or reaction device. ### Claim 3 (depends on 1) A mass spectrometer as claimed in claim 1, wherein said first mass to charge ratio filter or mass to charge ratio mass analyser is arranged and adapted in said first mode of operation to attenuate ions having mass to charge ratios outside of said first range. ### Claim 4 (depends on 1) A mass spectrometer as claimed in claim 1, wherein said first undesired charge state is selected from one or more of the following: (i) singly charged; (ii) doubly charged; (iii) triply charged; (iv) quadruply charged; (v) quintuply; and (vi) multiply charged. ### Claim 5 (depends on 1) A mass spectrometer as claimed in claim 1, wherein said first mass to charge ratio filter or mass to charge ratio mass analyser is arranged upstream or downstream of said ion mobility spectrometer or separator. ### Claim 6 (depends on 1) A mass spectrometer as claimed in claim 1, further comprising an ion guide, ion trap or ion trapping region arranged upstream of said ion mobility spectrometer or separator, wherein said ion guide, ion trap or ion trapping region is arranged to trap, store or accumulate ions and then to periodically pulse ions into or towards said ion mobility spectrometer or separator. ### Claim 7 A method of mass spectrometry using a mass spectrometer having an ion mobility spectrometer or separator, the method comprising: transmitting ions having mass to charge ratios within a first range through a first mass to charge ratio filter or mass to charge ratio mass analyser; separating ions according to ion mobility using the mobility spectrometer or separator, such that such that ions having substantially the same mass to charge ratio within the first range will exit the ion mobility spectrometer or separator at substantially different times; and attenuating ions in a mode of operation with attenuation means, wherein said attenuation means is configured such that it is not mass-selective and such that it either substantially allows all ions to be onwardly transmitted, or substantially attenuates all ions by preventing all ions from being transmitted, wherein said attenuation means comprises at least one of: an ion gate or ion barrier arranged downstream of said ion mobility spectrometer or separator; means for removing, attenuating or reducing the amplitude of an AC or RF voltage or potential which is applied to at least a portion of said ion mobility spectrometer or separator; and means for removing, attenuating or reducing the amplitude of an AC or RF voltage or potential which is applied to at least a portion of an ion guide or other ion optical device arranged downstream of said ion mobility spectrometer or separator wherein attenuating ions in a mode of operation with attenuation means comprises controlling the operation of said attenuation means so that said attenuation transmits substantially all ions during a first time period or first time window, and said attenuation means attenuates substantially all ions during a second time period or second time window, wherein said second time period or second time window is different from said first time period or first time window, wherein said second time period or second time window is selected such that operation of the attenuation means to attenuate substantially all ions during said second time period or second time window causes ions having mass to charge ratios within said first range but having one or more undesired first charge states to be attenuated. ### Claim 8 (depends on 7) A method as claimed in claim 7, wherein the mass spectrometer further comprises a collision, fragmentation or reaction device. ### Claim 9 (depends on 1) A mass spectrometer as claimed in claim 1, wherein said attenuation means comprises an ion gate or ion barrier arranged downstream of said ion mobility spectrometer or separator. ### Claim 10 (depends on 1) A mass spectrometer as claimed in claim 1, wherein said attenuation means comprises means for removing, attenuating or reducing the amplitude of an AC or RF voltage or potential which is applied to at least a portion of said ion mobility spectrometer or separator. ### Claim 11 (depends on 1) A mass spectrometer as claimed in claim 1, wherein said attenuation means comprises means for removing, attenuating or reducing the amplitude of an AC or RF voltage or potential which is applied to at least a portion of an ion guide or other ion optical device arranged downstream of said ion mobility spectrometer or separator. ### Claim 12 (depends on 7) A method as claimed in claim 7, wherein said attenuation means comprises an ion gate or ion barrier arranged downstream of said ion mobility spectrometer or separator. ### Claim 13 (depends on 7) A method as claimed in claim 7, wherein said attenuation means comprises means for removing, attenuating or reducing the amplitude of an AC or RF voltage or potential which is applied to at least a portion of said ion mobility spectrometer or separator. ### Claim 14 (depends on 7) A method as claimed in claim 7, wherein said attenuation means comprises means for removing, attenuating or reducing the amplitude of an AC or RF voltage or potential which is applied to at least a portion of an ion guide or other ion optical device arranged downstream of said ion mobility spectrometer or separator. ### Claim 15 (depends on 10) A mass spectrometer as claimed in claim 10, wherein when, in use, said attenuation means removes, attenuates or reduces the amplitude of an AC or RF voltage or potential which is applied to at least a portion of said ion mobility spectrometer or separator so that ions within at least a portion of said ion mobility spectrometer or separator are no longer confined radially within said ion mobility spectrometer or separator. ### Claim 16 (depends on 11) A mass spectrometer as claimed in claim 11, wherein when, in use, said attenuation means removes, attenuates or reduces the amplitude of an AC or RF voltage or potential which is applied to at least a portion of said ion guide or other ion optical device which is arranged downstream of said ion mobility spectrometer or separator then ions within at least a portion of said ion guide or other ion optical device are no longer confined radially within said ion guide or other ion optical device.