Micromass UK Limited

Miromass UK Limited

David John Langridge

Jason Lee Wildgoose

Martin Raymond Green

Kevin Giles

Daniel James Kenny

Keith George Richardson

Steven Derek Pringle

Robert Harold Bateman

John Brian Hoyes

Jeffery Mark Brown

Richard Barrington Moulds

Anthony James Gilbert

David Gordon

Kenneth Russell Worthington

Boris Kozlov

Jakub Ujma

Martin Palmer

Eleanor Riches

Darren Hewitt

A method of selecting ions comprises selecting ions corresponding to a target ion of interest by separating analyte ions according to their ion mobility, isolating first ions of the analyte ions, separating the first ions according to their ion mobility, and isolating second ions of the first ions. Preferably, the separation is accomplished by using a cyclic or closed-loop separator.

Method of selecting ions by ion mobility separation and isolation of ions

Disclosed herein are various methods and apparatus for performing charge detection mass spectrometry (CDMS). In particular, techniques are disclosed for monitoring a detector signal from a CDMS device to determine how many ions are present in the ion trap () of the CDMS device. For example, if no ions are present the measurement can then be terminated early. Similarly, if more than one ion is present, the measurement can be terminated early, or ions can be removed from the trap () until only a single ion remains. Techniques are also provided for increasing the probability of there being a single ion in the trap (). A technique for attenuating an ion beam is also provided.

Charge detection mass spectrometry

A method of mass filtering ions is disclosed comprising: providing a first, AC-only, mass filter (); providing a second mass filter () downstream of the first mass filter; applying a first AC voltage () to electrodes of the first mass filter so as to radially confine ions between the electrodes, and applying a second AC voltage () between electrodes of the first mass filter () so as to radially excite some of said ions such that these ions are not transmitted; and using the second mass filter () to mass filter ions; wherein at any given time the second mass filter () only transmits ions having a first range of mass to charge ratios and filters out all other ions; and wherein the step of applying the at least one second AC voltage () to electrodes of the first mass filter () radially excites ions such that at least some ions having mass to charge ratios above said first range are not transmitted into the second mass filter.

Mass filter having reduced contamination

A method is disclosed comprising: trapping ions in an ion trap (); applying a first force on the ions within the ion trap in a first direction, said force having a magnitude that is dependent upon the value of a physicochemical property of the ions; applying a second force on these ions in the opposite direction so that the ions separate according to the physicochemical property value as a result of the first and second forces; and then pulsing or driving ions out of one or more regions of the ion trap.

Separating ions in an ion trap

A method of operating a quadrupole device () is disclosed. A voltage source () applies a main quadrupolar voltage, an auxiliary quadrupolar voltage and a dipolar voltage to the quadrupole device (). This may be done such that only ions corresponding to a single X-band, X-band-like, Y-band or Y-band-like stability region are transmitted by the quadrupole device ().

Quadrupole devices

A dual-mode ion detector for a mass and/or ion mobility spectrometer comprising a first conversion electrode () that is maintained, in use, at a negative potential and arranged for converting incident positive ions () into secondary electrons (), and a second conversion electrode () that is maintained, in use, at a positive potential and arranged for converting incident negative ions () into secondary positive ions () and/or secondary electrons (). The detector also comprises an electron detecting surface () and an entrance electrode () for drawing ions into the ion detector. The ion detector is switchable between a first mode for detecting positive ions and a second mode for detecting negative ions.

Ion detector

A method of introducing and ejecting ions from an ion entry/exit device () is disclosed. The ion entry/exit device () has at least two arrays of electrodes (). The device is operated in a first mode wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays (() in a first direction such that a potential barrier moves along the at least one array in the first direction and drives ions into and/or out of the device in the first direction. The device is also operated in a second mode, wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays () in a second, different direction such that a potential barrier moves along the array in the second direction and drives ions into and/or out of the device in the second direction. The device provides a single, relatively simple device for manipulating ions in multiple directions. For example, the device may be used to load ions into or eject ions from an ion mobility separator in a first direction, and may then be used to cause ions to move through the ion mobility separator in the second direction so as to cause the ions to separate.

Ion entry/exit device

A method of operating a quadrupole device () is disclosed. The quadrupole device () is operated in a mode of operation by applying a repeating voltage waveform comprising a main drive voltage and at least one auxiliary drive voltage is applied to the quadrupole device to the quadrupole device (). The intensity of ions passing into the quadrupole device is varied with time in synchronisation with the repeating voltage waveform. This may be done such that the number of ions per unit phase which initially experience a phase within a first range of phases of the repeating voltage waveform is greater than the number of ions per unit phase which initially experience a phase within a second range of phases of the repeating voltage waveform.

A method of ion mobility and/or mass spectrometry is disclosed in which the ion mobility and/or mass to charge ratio of an ion is determined using an algorithm or relationship that relates the transit time or average ion velocity of the ion through an ion separation device in which one or more time-varying electric field is used to separate ions passing therethrough to one or more parameters for the device, the mass to charge ratio of the ion and the ion mobility of the ion.

Mobility and mass measurement using time-varying electric fields

A method of filtering ions according to their ion mobility using a device is disclosed, the method comprising a plurality of electrodes and one or more voltage source(s) arranged and adapted to apply voltages to the plurality of electrodes, the method comprising, generating using the one or more voltage source(s) one or more local separation region(s), wherein ions can be separated within each local separation region according to their ion mobility, and moving each local separation region axially along the device with a certain velocity such that, for each local separation region, ions having a value of their ion mobility falling within a selected range are transmitted axially along the device with that local separation region whereas ions having higher and/or lower ion mobility falling outside that range escape the local separation region, wherein any ions that escape the local separation region(s) are removed from within the device and/or otherwise kept apart from those ions falling within the selected range(s).

Ion filtering devices

A method of operating a quadrupole device is disclosed. The method comprises operating the quadrupole device in a first mode of operation, wherein ions within a first mass to charge ratio range are selected and/or transmitted by the quadrupole device, and operating the quadrupole device in a second mode of operation, wherein ions within a second different mass to charge ratio range are selected and/or transmitted by the quadrupole device. In the first mode of operation, the quadrupole device is operated in a normal mode of operation wherein a main drive voltage is applied to the quadrupole device, or in a first X-band or Y-band mode of operation wherein a main drive voltage and two or more auxiliary drive voltages are applied to the quadrupole device. In the second mode of operation, the quadrupole device is operated in a second X-band or Y-band mode of operation wherein a main drive voltage and two or more auxiliary drive voltages are applied to the quadrupole device.

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Macclesfield, United Kingdom

David John Langridge