Mass spectrometer

Patent metadata

Field	Value
Publication number	US-9281171-B2
Application number	US-72126005-A
Country	US
Kind code	B2
Filing date	Dec 8, 2005
Priority date	Dec 8, 2004
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

A mass spectrometer is disclosed comprising a mass selective ion trap or mass analyzer arranged upstream of an ion guide. Ions are scanned out of the mass selective ion trap or mass analyzer and are received in one or more axial potential wells created or formed within the ion guide. One or more transient DC voltages or potentials are preferably applied to the ion guide in order to create a plurality of axial potential wells which are translated along the length of the ion guide. Ions are released in packets from the exit of the ion guide and are orthogonally acceleration into a drift or flight region of an orthogonal acceleration Time of Flight mass analyzer with a relatively high duty cycle.

First claim

The invention claimed is:

1. A mass spectrometer comprising:
a mass selective ion trap or mass analyser for separating ions exclusively according to mass or mass to charge ratio;
a first ion guide arranged downstream of said mass selective ion trap or mass analyser, said first ion guide being arranged to receive ions from said mass selective ion trap or mass analyser, and wherein said first ion guide comprises a plurality of electrodes;
a first voltage supply arranged and adapted to apply one or more voltages or one or more voltage waveforms to said plurality of electrodes so that in a first mode of operation ions received from said mass selective ion trap or mass analyser are retained or confined or transported or translated in separate regions or portions of said first ion guide;
a mass analyser arranged downstream of said first ion guide; and
a control system arranged and adapted to switch or repeatedly switch, at least once every 10 seconds, the potential difference through which ions pass prior to entering said first ion guide between a high fragmentation mode of operation wherein ions are substantially fragmented upon entering said first ion guide and a low fragmentation mode of operation wherein substantially fewer ions are fragmented or wherein substantially no ions are fragmented upon entering said first ion guide.

2. A mass spectrometer as claimed in claim 1 , wherein said mass selective ion trap or mass analyser is selected from the group consisting of: (i) a 3D quadrupole or Paul ion trap or mass analyser; (ii) a 2D or linear quadrupole ion trap or mass analyser; (iii) a cylindrical ion trap or mass analyser; (iv) a cubic ion trap or mass analyser; (v) an AC or RF voltage supply for confining ions radially within said mass selective ion trap or mass analyser and a DC voltage supply for confining ions axially within said mass selective ion trap or mass analyser; (vi) a Penning ion trap; and (vii) an electrostatic or orbitrap mass analyser.

3. A mass spectrometer as claimed in claim 1 , further comprising an AC or RF voltage supply arranged and adapted to apply an AC or RF voltage to said mass selective ion trap or mass analyser, wherein said AC or RF voltage supply is arranged and adapted to supply an AC or RF voltage having an amplitude selected from the group consisting of: (i) <50 V peak to peak; (ii) 50-100 V peak to peak; (iii) 100-150 V peak to peak; (iv) 150-200 V peak to peak; (v) 200-250 V peak to peak; (vi) 250-300 V peak to peak; (vii) 300-350 V peak to peak; (viii) 350-400 V peak to peak; (ix) 400-450 V peak to peak; (x) 450-500 V peak to peak; and (xi) >500 V peak to peak.

4. A mass spectrometer as claimed in claim 3 , wherein said AC or RF voltage supply is arranged and adapted to supply an AC or RF voltage having a frequency selected from the group consisting of: (i) <100 kHz; (ii) 100-200 kHz; (iii) 200-300 kHz; (iv) 300-400 kHz; (v) 400-500 kHz; (vi) 0.5-1.0 MHz; (vii) 1.0-1.5 MHz; (viii) 1.5-2.0 MHz; (ix) 2.0-2.5 MHz; (x) 2.5-3.0 MHz; (xi) 3.0-3.5 MHz; (xii) 3.5-4.0 MHz; (xiii) 4.0-4.5 MHz; (xiv) 4.5-5.0 MHz; (xv) 5.0-5.5 MHz; (xvi) 5.5-6.0 MHz; (xvii) 6.0-6.5 MHz; (xviii) 6.5-7.0 MHz; (xix) 7.0-7.5 MHz; (xx) 7.5-8.0 MHz; (xxi) 8.0-8.5 MHz; (xxii) 8.5-9.0 MHz; (xxiii) 9.0-9.5 MHz; (xxiv) 9.5-10.0 MHz; and (xxv) >10.0 MHz.

5. A mass spectrometer as claimed in claim 1 , further arranged and adapted to maintain in a mode of operation said mass selective ion trap or mass analyser at a pressure selected from the group consisting of: (i) <1.0×10 −1 mbar; (ii) <1.0×10 −2 mbar; (iii) <1.0×10 −3 mbar; (iv) <1.0×10 −4 mbar; (v) <1.0×10 −5 mbar; (vi) <1.0×10 −6 mbar; (vii) <1.0×10 −7 mbar; (viii) <1.0×10 −8 mbar; (ix) <1.0×10 −9 mbar; (x) <1.0×10 −10 mbar; (xi) >1.0×10 −3 mbar; (xii) >1.0×10 −2 mbar; (xiii) >1.0×10 −1 mbar; (xiv) >1 mbar; (xv) >10 mbar; (xvi) >100 mbar; (xvii) >5.0×10 −3 mbar; (xviii) >5.0×10 −2 mbar; (xix) 10 −3 −10 −2 mbar; and (xx) 10 −4 −10 −1 mbar.

6. A mass spectrometer as claimed in claim 1 , wherein ions are trapped but are not substantially fragmented within said mass selective ion trap or mass analyser.

7. A mass spectrometer as claimed in claim 1 , further comprising ejection means arranged and adapted either: (i) to resonantly or mass selectively eject ions from said mass selective ion trap or mass analyser; (ii) to non-resonantly or mass selectively eject ions from said mass selective ion trap or mass analyser; or (iii) to eject or emit ions axially or radially from said mass selective ion trap or mass analyser.

8. A mass spectrometer as claimed in claim 1 , wherein said first ion guide is selected from the group consisting of:
(i) a segmented multipole rod set;
(ii) an ion tunnel or ion funnel; and
(iii) a stack or array of planar, plate or mesh electrodes.

9. A mass spectrometer as claimed in claim 1 , wherein said first ion guide comprises a plurality of axial segments or at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 axial segments.

10. A mass spectrometer as claimed in claim 1 , further comprising a transient DC voltage supply arranged and adapted to apply one or more transient DC voltages or potentials or one or more transient DC voltage or potential waveforms to electrodes forming said first ion guide in order to urge at least some ions along at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100% of the axial length of said first ion guide.

11. A mass spectrometer as claimed in claim 1 , further comprising an AC or RF voltage supply arranged and adapted to apply two or more phase-shifted AC or RF voltages to electrodes forming said first ion guide in order to urge at least some ions along at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100% of the axial length of said first ion guide.

12. A mass spectrometer as claimed in 1 , further arranged and adapted to accelerate ions emerging from said mass selective ion trap or mass analyser into said first ion guide and wherein in a second mode of operation at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100% of said ions are caused to fragment upon entering said first ion guide.

13. A mass spectrometer as claimed in claim 12 , arranged and adapted to progressively vary or increase the kinetic energy of ions emerging from said mass selective ion trap or mass analyser as are transmitted to said first ion guide.

14. A mass spectrometer as claimed in claim 1 , wherein in said high fragmentation mode of operation ions entering said first ion guide are accelerated through a potential difference selected from the group consisting of: (i) ≧10 V; (ii) ≧20 V; (iii) ≧30 V; (iv) ≧40 V; (v) ≧50 V; (vi) ≧60 V; (vii) ≧70 V; (viii) ≧80 V; (ix) ≧90 V; (x) ≧100 V; (xi) ≧110 V; (xii) ≧120 V; (xiii) ≧130 V; (xiv) ≧140 V; (xv) ≧150 V; (xvi) ≧160 V; (xvii) ≧170 V; (xviii) ≧180 V; (xix) ≧190 V; and (xx) ≧200 V.

15. A mass spectrometer as claimed in claim 1 , wherein in said low fragmentation mode of operation ions entering said first ion guide are accelerated through a potential difference selected from the group consisting of: (i) ≦20 V; (ii) ≦15 V; (iii) ≦10 V; (iv) ≦5V; and (v) ≦1V.

16. A mass spectrometer as claimed in claim 1 , wherein said control system is arranged and adapted to switch said first ion guide between said high fragmentation mode of operation and said low fragmentation mode of operation at least once every 1 ms, 5 ms, 10 ms, 15 ms, 20 ms, 25 ms, 30 ms, 35 ms, 40 ms, 45 ms, 50 ms, 55 ms, 6

Assignees

• Bateman Robert Harold
• Giles Kevin
• Brown Jeffery Mark
• Pringle Steven Derek
• Wildgoose Jason Lee
• Micromass Ltd

Inventors

• Bateman Robert Harold
• Giles Kevin
• Brown Jeffery Mark
• Pringle Steven Derek
• Wildgoose Jason Lee

Classifications

• H01J49/004

  Combinations of spectrometers, tandem spectrometers, e.g. MS/MS, MSn · CPC title

• H01J49/062 Primary

  Ion guides (linear ion traps performing mass selection H01J49/4225, mass filters H01J49/421) · CPC title

• H01J49/34

  Dynamic spectrometers · CPC title

• H01J49/06 Primary

  Electron- or ion-optical arrangements · CPC title