EP0237268A2
Expired / Lapsed
EP
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Method of mass analysing a sample
Assignee: Thermo Finnigan LLC
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Filing: 1987-03-05
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Granted: —
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Expires: 2007-03-05
Abstract
Abstract In a method of mass analyzing a sample in a quadrupole ion trap mass spectrometer (10) the number of sample ions formed in the ion trap prior to analysis is controlled (21) to avoid saturation and space charge in the ion trap.
Inventors
- 👤 George C. Stafford Jr.
- 👤 Dennis M. Taylor
- 👤 Stephen C. Bradshaw
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 20:19
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/26; H01J49/34; H01J49/42; H01J49/4205; H01J49/424; H01J49/426; H01J49/4265; H01J49/427; H01J49/429
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
93 words
A method of mass analyzing a sample which comprises the steps of defining a three-dimensional quadrupole trapping field into which the sample is introduced and ionized whereby ions in the range of interest are formed and simultaneously trapped, and varying the three-dimensional trapping field so that ions of consecutive specific masses become sequentially unstable, leave the trapping field and are detected to provide an indication of the trapped ion masses, characterised by the step of controlling the number of sample ions contained in the ion trap population to minimize saturation and space charge.
Claim 2
Independent Claim
93 words
A method of mass analyzing a sample which comprises the steps of defining a three-dimensional quadrupole trapping field into which the sample is introduced and ionized whereby ions in the range of interest are formed and simultaneously trapped, and varying the three-dimensional trapping field so that ions of consecutive specific masses become sequentially unstable, leave the trapping field and are detected to provide an indication of the trapped ion masses, characterised by the step of controlling the number of sample ions contained in the ion trap population to minimize saturation and space charge.
Claim 3
Dependent Claim
72 words
A method as claimed in Claim 1, in which the sample is ionized by projecting an ionizing beam into the trapping field to ionize the sample therein whereby ions are formed and trapped in said trapping field, characterised in that control of the number of sample ions is effected by controlling the ionizing beam to control the number of ions formed so that the ion trap is not saturated or space charged.
Claim 4
Dependent Claim
19 words
A method as claimed in Claim 2, characterised in that the ionizing beam is controlled by controlling its duration.
Claim 5
Dependent Claim
19 words
A method as claimed in Claim 2, characterised in that the ionizing beam is controlled by controlling its intensity.
Claim 6
Dependent Claim
20 words
A method as claimed in Claim 2, 3 or 4, characterised in that the ionizing beam is an electron beam.
Claim 7
Independent Claim
69 words
A method as claimed in any preceding claim, characterised in that the number of sample ions formed is controlled by ionizing the sample for a short fixed period of time, measuring the total ions formed, clearing the ion trap, again introducing the sample into the ion trap, and controlling the number of sample ions formed on the basis of the total ions formed to minimize saturation and space charge.
Claim 8
Independent Claim
39 words
A method as claimed in any one of Claims 2 to 5, characterised by the steps of measuring the ion content of the ion trap prior to performing the analysis, and using the measurement to control the ionizing beam.
Claim 9
Dependent Claim
32 words
A method as claimed in Claim 7, characterised in that the ion content of the ion trap is measured by ionizing for a short predetermined time and measuring the total ion content.
References Cited (Backward Citations)
No citation records indexed.
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