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US6147348A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for performing a scan function on quadrupole ion trap mass spectrometers

Assignee: University of Florida
•
Filing: 1999-05-17
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Granted: 2000-11-14
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Expires: 2019-05-17
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Abstract

Abstract The subject invention pertains to a scan function which will allow parent and neutral loss scans, with a reduced number of false positives, greater detection efficiency, shortened time periods, and enhanced mass resolution, to be performed on the quadrupole ion trap mass spectrometer. In a specific embodiment, the subject invention involves first trapping ions of interest and obtaining a mass spectrum of the m/z range of interest. The (m/z)'s which are present and meet certain predetermined criteria can then be selected and stored. Ions are again trapped in the ion trap and then all ions with (m/z)'s below that of the first ion of interest are ejected. The first ion of interest is resonantly excited to cause CID and the presence of a particular daughter ion is then determined using a standard mass-selective instability scan over a narrow m/z range with resonant ejection at a predetermined ejection q z . The ion trap is then cleared of all ions with (m/z)'s below that of the next ion of interest and the process is repeated.

Inventors

  • 👤 Scott T. Quarmby
  • 👤 Richard A. Yost

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-07 07:30
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/26; H01J49/34; H01J49/42; H01J49/4205; H01J49/424; H01J49/004; H01J49/0045; H01J49/0063; H01J49/0081; H01J49/426; H01J49/427; H01J49/429

Claims Analysis

Total Claims: 28
Claim 1
Independent Claim 163 words
A method for performing a scan function on a quadrupole ion trap, comprising the following steps: a) trapping sample ions in the ion trap; b) obtaining a mass spectrum of the sample ions; c) selecting and storing the mass-to-charge ratios of the ions which are present and/or meet at least one predetermined criterion; d) trapping additional sample ions in the trap; e) ejecting all ions with mass-to-charge ratios below the lowest stored mass-to-charge ratio; f) resonantly exciting ions of the lowest stored mass-to-charge ratio; g) performing a mass-selective instability scan over a mass-to-charge ratio range of interest; h) ejecting all ions with mass-to-charge ratios below the next lowest stored mass-to-charge ratio; i) resonantly exciting ions of the next lowest stored mass-to-charge ratio; j) performing a mass-selective instability scan over a mass-to-charge ratio range of interest; and k) repeating steps h, i, and j until ions of all stored mass-to-charge ratios have been resonantly excited, wherein the scan provides information about the sample ions.
Claim 2
Independent Claim 163 words
A method for performing a scan function on a quadrupole ion trap, comprising the following steps: a) trapping sample ions in the ion trap; b) obtaining a mass spectrum of the sample ions; c) selecting and storing the mass-to-charge ratios of the ions which are present and/or meet at least one predetermined criterion; d) trapping additional sample ions in the trap; e) ejecting all ions with mass-to-charge ratios below the lowest stored mass-to-charge ratio; f) resonantly exciting ions of the lowest stored mass-to-charge ratio; g) performing a mass-selective instability scan over a mass-to-charge ratio range of interest; h) ejecting all ions with mass-to-charge ratios below the next lowest stored mass-to-charge ratio; i) resonantly exciting ions of the next lowest stored mass-to-charge ratio; j) performing a mass-selective instability scan over a mass-to-charge ratio range of interest; and k) repeating steps h, i, and j until ions of all stored mass-to-charge ratios have been resonantly excited, wherein the scan provides information about the sample ions.
Claim 3
Independent Claim 141 words
A method for performing a scan function on a quadrupole ion trap to obtain information about a sample, comprising the following steps: a) trapping sample ions in the ion trap; b) obtaining a mass spectrum of the sample ions; c) selecting the mass-to-charge ratios of the ions which meet at least one criterion; d) ejecting all ions with mass-to-charge ratios below the lowest selected mass-to-charge ratio; e) fragmenting ions of the lowest selected mass-to-charge ratio; f) obtaining a mass spectrum over a mass-to-charge ratio range of interest; g) ejecting all ions with mass-to-charge ratios below the next lowest selected mass-to-charge ratio; h) fragmenting ions of the next lowest selected mass-to-charge ratio; i) obtaining a mass spectrum over a mass-to-charge ratio range of interest; and j) repeating steps g, h, and i until ions of each selected mass-to-charge ratios have been fragmented.
Claim 4
Independent Claim 141 words
A method for performing a scan function on a quadrupole ion trap to obtain information about a sample, comprising the following steps: a) trapping sample ions in the ion trap; b) obtaining a mass spectrum of the sample ions; c) selecting the mass-to-charge ratios of the ions which meet at least one criterion; d) ejecting all ions with mass-to-charge ratios below the lowest selected mass-to-charge ratio; e) fragmenting ions of the lowest selected mass-to-charge ratio; f) obtaining a mass spectrum over a mass-to-charge ratio range of interest; g) ejecting all ions with mass-to-charge ratios below the next lowest selected mass-to-charge ratio; h) fragmenting ions of the next lowest selected mass-to-charge ratio; i) obtaining a mass spectrum over a mass-to-charge ratio range of interest; and j) repeating steps g, h, and i until ions of each selected mass-to-charge ratios have been fragmented.
Claim 5
Dependent Claim 36 words
The method according to claim 2, wherein after the step of selecting the mass-to-charge ratios of the ions which meet at least one criterion, further comprising the step of trapping additional sample ions in the trap.
Claim 6
Dependent Claim 50 words
The method according to claim 2, wherein the steps of obtaining a mass spectrum over a mass-to-charge ratio range of interest comprises the following steps: calculating the RF voltage required for resonant ejection of ions having a predetermined mass-to-charge ratio; and resonantly ejecting any ions having said predetermined mass-to-charge ratio.
Claim 7
Dependent Claim 17 words
The method according to claim 4 wherein said predetermined mass-to-charge ratio corresponds to a particular daughter ion.
Claim 8
Dependent Claim 84 words
The method according to claim 2, wherein the step of obtaining a mass spectrum over a mass-to-charge ratio range of interest comprises the following steps: calculating the RF voltage required for resonant ejection of ions having a mass-to-charge ratio which is a predetermined amount lower than the mass-to-charge ratio of the ions fragmented in the prior step; and resonantly ejecting any ions having a mass-to-charge ratio which is a predetermined amount lower than the mass-to-charge ratio of the ions fragmented in the prior step.
Claim 9
Dependent Claim 17 words
The method according to claim 6, wherein said predetermined amount lower corresponds to a particular neutral loss.
Claim 10
Dependent Claim 20 words
The method according to claim 2, wherein all resonant ejections are performed at approximately the same ejection q z .
Claim 11
Dependent Claim 13 words
The method according to claim 2, wherein ions are fragmented using resonant excitation.
Claim 12
Dependent Claim 20 words
The method according to claim 9, wherein all resonant excitations are performed at approximately the same CID q z .
Claim 13
Dependent Claim 28 words
The method according to claim 2, wherein the criterion in step "c" is the n most intense mass-to-charge ratios in the mass spectrum, where n is an integer.
Claim 14
Dependent Claim 18 words
The method according to claim 2, wherein said scan is programmed on a quadrupole ion trap mass spectrometer.
Claim 15
Dependent Claim 15 words
The method according to claim 12, wherein said scan is fully automated without operator intervention.
Claim 16
Dependent Claim 49 words
The method according to claim 2, wherein the step of obtaining a mass spectrum over a mass-to-charge ratio range of interest further comprises real-time calculations in order to vary the RF voltage such that resonant ejection of the ions is performed at an approximately constant ejection q z .
Claim 17
Dependent Claim 37 words
The method according to claim 2, wherein the steps of fragmenting ions further comprise real-time calculations in order to vary the RF voltage such that resonant excitation is performed at an approximately constant CID q z .
Claim 18
Dependent Claim 25 words
The method according to claim 2, wherein additional sample ions are not trapped in the trap between successive repetitions of steps g, h, and i.
Claim 19
Dependent Claim 40 words
The method according to claim 2, wherein ions having a mass-to-charge ratio higher than the ions fragmented in steps e and h continue to be trapped in the ion trap immediately following the performance of steps e and h, respectively.
Claim 20
Dependent Claim 41 words
The method according to claim 2, wherein the step of selecting the mass-to-charge ratios of the ions which meet at least one criterion is based, at least in part, on the mass spectrum of the sample ions obtained in step b.
Claim 21
Dependent Claim 16 words
The method according to claim 2, wherein said method allows the interrogation of an unknown sample.
Claim 22
Independent Claim 89 words
A method for performing a scan on an ion trap, comprising the following steps: a) trapping sample ions in the ion trap; b) performing an initial scan of the sample ions; c) selecting the mass-to-charge ratios of the ions which meet at least one criterion; d) performing, for at least one selected mass-to-charge ratio, the following steps: i) ejecting all ions with mass-to-charge ratios below said selected mass-to-charge ratio; ii) fragmenting ions of said selected mass-to-charge ratio; iii) obtaining a mass spectrum over a mass-to-charge ratio range of interest.
Claim 23
Independent Claim 89 words
A method for performing a scan on an ion trap, comprising the following steps: a) trapping sample ions in the ion trap; b) performing an initial scan of the sample ions; c) selecting the mass-to-charge ratios of the ions which meet at least one criterion; d) performing, for at least one selected mass-to-charge ratio, the following steps: i) ejecting all ions with mass-to-charge ratios below said selected mass-to-charge ratio; ii) fragmenting ions of said selected mass-to-charge ratio; iii) obtaining a mass spectrum over a mass-to-charge ratio range of interest.
Claim 24
Dependent Claim 36 words
The method according to claim 20, wherein after the step of selecting the mass-to-charge ratios of the ions which meet at least one criterion, further comprising the step of trapping additional sample ions in the trap.
Claim 25
Dependent Claim 29 words
The method according to claim 20, wherein step "d" is performed on each selected mass-to-charge ratio, sequentially from the lowest selected mass-to-charge ratio to the highest selected mass-to-charge ratio.
Claim 26
Dependent Claim 50 words
The method according to claim 20, wherein the step of obtaining a mass spectrum over a mass-to-charge ratio range of interest, comprises the following steps: calculating the RF voltage required for resonant ejection of ions having a predetermined mass-to-charge ratio; and resonantly ejecting any ions having said predetermined mass-to-charge ratio.
Claim 27
Dependent Claim 83 words
The method, according to claim 20, wherein the step of obtaining a mass spectrum over a mass-to-charge ratio range of interest, comprises the following steps: calculating the RF voltage required for resonant ejection of ions having a mass-to-charge ratio which is a predetermined amount lower than the mass-to-charge ratio of the ions fragmented in the prior step; and resonantly ejecting ions having a mass-to-charge ratio which is a predetermined amount lower than the mass-to-charge ratio of the ions fragmented in the prior step.
Claim 28
Dependent Claim 35 words
The method according to claim 20, wherein all resonant ejections are performed at approximately the same ejection q z and all resonant excitation ion fragmentations are performed with approximately the same CID q z .

References Cited (Backward Citations)

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US5107109A Cited
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US5171991A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2003-11-14 2004-05-15 2004-11-14 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2007-11-14 2008-05-15 2008-11-14 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2011-11-14 2012-05-15 2012-11-14 $7700.00 Window Closed / Lapsed

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