MASS SPECTROMETER

• US 20100294923A1
• Filed: 10/16/2007
• Published: 11/25/2010
• Est. Priority Date: 10/16/2006
• Status: Active Grant

• Current Assignee: Micromass UK Ltd (Waters Corporation)
• Original Assignee: Micromass UK Ltd (Waters Corporation)
• Inventors: Bateman, Robert Harold, Pringle, Steven Derek, Green, Martin, Wildgoose, Jason Lee, Kenny, Daniel James
• Granted Patent: US 8,633,435 B2
• Time in Patent Office: Days
• US Class Current: 250/282
• CPC Class Codes: H01J 49/0031 Step by step routines describing the use of the apparatus H01J49/0081 takes precedence
• CPC Class Codes: H01J 49/004 Combinations of spectrometers, tandem spectrometers, e.g. MS/MS, MSn
• CPC Class Codes: H01J 49/0045 characterised by the fragmentation or other specific reaction
• CPC Class Codes: H01J 49/005 by collision with gas, e.g. by introducing gas or by accelerating ions with an electric field
• CPC Class Codes: H01J 49/065 having stacked electrodes, e.g. ring stack, plate stack
• CPC Class Codes: H01J 49/34 Dynamic spectrometers
• CPC Class Codes: H01J 49/4235 Stacked rings or stacked plates

Abstract

A collision or fragmentation cell (4) is disclosed comprising a plurality of electrodes wherein a first RF voltage (7a) is applied to an upstream group of electrodes and a second different RF voltage (7b) is applied to a downstream group of electrodes. The radial confinement of parent ions entering the collision or fragmentation cell (4) is optimised by the first RF voltage applied to the upstream group of electrodes and the radial confinement of daughter or fragment ions produced within the collision or fragmentation cell (4) is optimised by the second different RF voltage applied to the downstream group of electrodes.

Claims

1. A mass spectrometer comprising:

a collision, fragmentation or reaction device, said collision, fragmentation or reaction device comprising a plurality of electrodes comprising at least a first section comprising a first group of electrodes and a second separate section comprising a second separate group of electrodes;

a first device for applying or supplying a first AC or RF voltage having a first frequency and a first amplitude to said first group of electrodes so that, in use, ions having a first mass to charge ratio experience a first radial pseudo-potential electric field or force having a first strength or magnitude which acts to confine ions radially within said first group of electrodes or said first section; and

a second device for applying or supplying a second AC or RF voltage having a second frequency and a second amplitude to said second group of electrodes so that, in use, ions having said first mass to charge ratio experience a second radial pseudo-potential electric field or force having a second strength or magnitude which acts to confine ions radially within said second group of electrodes or said first section, wherein said second strength or magnitude is different to said first strength or magnitude.

2. A mass spectrometer as claimed in claim 1, wherein said first AC or RF voltage is not applied to said second group of said electrodes and said second AC or RF voltage is not applied to said first group of electrodes.

23. A mass spectrometer as claimed in claim 1, wherein said first frequency is substantially different from said second frequency and/or wherein said first amplitude is substantially different from said second amplitude.

40. A mass spectrometer as claimed in claim 1, wherein said collision, fragmentation or reaction device comprises n sections, wherein each section comprises one or more electrodes and wherein the amplitude and/or frequency and/or phase difference of an AC or RF voltage applied to said sections in order to confine ions radially, in use, within said collision, fragmentation or reaction device progressively increases, progressively decreases, linearly increases, linearly decreases, increases in a stepped, progressive or other manner, decreases in a stepped, progressive or other manner, increases in a non-linear manner or decreases in a non-linear manner along the axial length of said collision, fragmentation or reaction device.

44. A mass spectrometer as claimed in claim 1, wherein said collision, fragmentation or reaction device comprises a plurality of electrodes having apertures through which ions are transmitted in use.

70. A mass spectrometer as claimed in claim 1, wherein the axial length and/or the centre to centre spacing of said electrodes progressively increases, progressively decreases, linearly increases, linearly decreases, increases in a stepped, progressive or other manner, decreases in a stepped, progressive or other manner, increases in a non-linear manner or decreases in a non-linear manner along the axial length of said collision, fragmentation or reaction device.

71. A mass spectrometer as claimed in claim 1, wherein said collision, fragmentation or reaction device comprises n sections, wherein each section comprises one or more electrodes and wherein the amplitude and/or frequency and/or phase difference of an AC or RF voltage applied to said sections in order to confine ions radially within said collision, fragmentation or reaction device is arranged to progressively increase with time, progressively decrease with time, linearly increase with time, linearly decrease with time, increase in a stepped, progressive or other manner with time, decrease in a stepped, progressive or other manner with time, increase in a non-linear manner with time or decrease in a non-linear manner with time.

75. A mass spectrometer as claimed in claim 1, further comprising a first mass filter or mass analyser arranged upstream of said collision, fragmentation or reaction device and/or a second mass filter or mass analyser arranged downstream of said collision, fragmentation or reaction device.

79. A mass spectrometer as claimed in claim 1, further comprising means for driving or urging ions along and/or through at least a portion of the axial length of said collision, fragmentation or reaction device.

80. A mass spectrometer as claimed in claim 79, wherein said means for driving or urging ions comprises means for generating a linear, non-linear or stepped axial DC electric field along at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or 100% of said first section and/or said second section and/or said third section of said collision, fragmentation or reaction device or of the whole length of said collision, fragmentation or reaction device.

83. A mass spectrometer as claimed in claim 79, wherein said means for driving or urging ions comprises means for applying a multiphase AC or RF voltage, one or more transient DC voltages or one or more DC voltage or potential waveforms to at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or 100% of said first section and/or said second section and/or said third section of said collision, fragmentation or reaction device or of the whole length of said collision, fragmentation or reaction device.

104. A mass spectrometer as claimed in claim 1, further comprising one or more electrodes arranged at the entrance and/or exit of said collision, fragmentation or reaction device, wherein in a mode of operation ions are pulsed into and/or out of said collision, fragmentation or reaction device.

3-22. -22. (canceled)

24-39. -39. (canceled)

41-43. -43. (canceled)

45-69. -69. (canceled)

72-74. -74. (canceled)

76-78. -78. (canceled)

81-82. -82. (canceled)

84-103. -103. (canceled)

105-111. -111. (canceled)

112. A method of mass spectrometry comprising:

providing a collision, fragmentation or reaction device, said collision, fragmentation or reaction device comprising a plurality of electrodes comprising at least a first section comprising a first group of electrodes and a second separate section comprising a second separate group of electrodes;

applying or supplying a first AC or RF voltage having a first frequency and a first amplitude to said first group of electrodes so that ions having a first mass to charge ratio experience a first radial pseudo-potential electric field or force having a first strength or magnitude which acts to confine ions radially within said first group of electrodes or the first section; and

applying or supplying a second AC or RF voltage having a second frequency and a second amplitude to said second group of electrodes so that ions having said first mass to charge ratio experience a second radial pseudo-potential electric field or force having a second strength or magnitude which acts to confine ions radially within said second group of electrodes or the second section, wherein said second strength or magnitude is different to said first strength or magnitude.

113-121. -121. (canceled)

122. A method of mass spectrometry comprising:

providing a collision, fragmentation or reaction device wherein ions having a first mass to charge ratio experience a first non-zero radial pseudo-potential electric field or force at a first time and a second different non-zero radial pseudo-potential electric field or force at a second later time.

123. (canceled)

124. A method of mass spectrometry comprising:

providing a collision, fragmentation or reaction device comprising a first section and a second section; and

progressively increasing or progressively decreasing a radial pseudo-potential electric field or force maintained along at least 1% of said first section or said second section or of the whole length of said collision, fragmentation or reaction device as a function of time.