US4005291A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ionization method for mass spectrometry
Assignee: Massachusetts Institute of Technology
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Filing: 1973-09-27
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Granted: 1977-01-25
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Expires: 1993-09-27
Abstract
Abstract A gas, vapor or aerosol substance is ionized for mass spectral analysis by passing the substance through a chemical ionization zone in the presence of (a) charge exchange reactant gas or hydrogen and (b) a chemical ionization reactants' gas. The ionized substance can be passed directly to a mass spectrometer or through an electron impact ionization zone and then to the mass spectrometer.
Inventors
- 👤 Guy P. Arsenault
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:40
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/02; H01J49/10; H01J49/14; H01J49/145; H01J49/147
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
158 words
A method for analyzing a gaseous, vaporous or aerosol substance comprising the steps of chemically ionizing said substance in a chemical ionization zone at a chemical ionization pressure in the presence of a first gas comprising at least one selected from the group consisting of hydrogen and charge exchange reactant gases and a second gas comprising a chemical ionization reaction gas, said first and second gases being admixed with said substance in sufficient amount to effect chemical ionization of said substance, passing the first and second gases and the chemically ionized substance produced in said chemical ionization zone into an electron-impact ionization zone through an aperture sufficiently small to maintain a pressure drop between said zones, said electron-impact ionization zone being maintained at an electron-impact ionization pressure and obtaining the mass spectra of the ionized substances formed in said chemical ionization zone by passing the output of the electron-impact ionization zone to the input of a mass spectrometer.
Claim 2
Independent Claim
158 words
A method for analyzing a gaseous, vaporous or aerosol substance comprising the steps of chemically ionizing said substance in a chemical ionization zone at a chemical ionization pressure in the presence of a first gas comprising at least one selected from the group consisting of hydrogen and charge exchange reactant gases and a second gas comprising a chemical ionization reaction gas, said first and second gases being admixed with said substance in sufficient amount to effect chemical ionization of said substance, passing the first and second gases and the chemically ionized substance produced in said chemical ionization zone into an electron-impact ionization zone through an aperture sufficiently small to maintain a pressure drop between said zones, said electron-impact ionization zone being maintained at an electron-impact ionization pressure and obtaining the mass spectra of the ionized substances formed in said chemical ionization zone by passing the output of the electron-impact ionization zone to the input of a mass spectrometer.
Claim 3
Dependent Claim
44 words
The method of claim 1 wherein the product of said chemical ionization zone is subjected to electron-impact ionization in said electron-impact ionization zone; and obtaining the mass spectrum of the ionized substance formed in said chemical ionization zone and in said electron-impact ionization zone.
Claim 4
Dependent Claim
60 words
The method of claim 2 comprising alternatively obtaining a first mass spectra of ionized substances formed in said chemical ionization zone and a second mass spectra of ionized substances formed in said electron-impact ionization zone by alternately energizing said zones, wherein said first spectra and said second spectra are both obtained within a total elapsed time of about 30 seconds.
Claim 5
Dependent Claim
56 words
The method of claim 3 including the previous steps of separating said substance into components in a gas chromatograph and passing the effluent containing said components from said chromatograph to said chemical ionization zone, and wherein said two mass spectra are both obtained within the time width at half-height of a peak component of said effluent.
Claim 6
Dependent Claim
42 words
The method of claim 2 including the steps of energizing both of said ionization zones during passage therethrough of said gaseous substance so as to obtain a mass spectrum simultaneously indicative both of chemical ionization and of electron-impact ionization of said substance.
Claim 7
Dependent Claim
18 words
The method of claim 1 wherein said first gas is helium and said second gas is water vapor.
Claim 8
Dependent Claim
18 words
The method of claim 2 wherein said first gas is helium and said second gas is water vapor.
Claim 9
Dependent Claim
18 words
The method of claim 3 wherein said first gas is helium and said second gas is water vapor.
Claim 10
Dependent Claim
18 words
The method of claim 4 wherein said first gas is helium and said second gas is water vapor.
Claim 11
Dependent Claim
18 words
The method of claim 5 wherein said first gas is helium and said second gas is water vapor.
Claim 12
Dependent Claim
18 words
The method of claim 1 wherein said first gas is hydrogen and said second gas is water vapor.
Claim 13
Dependent Claim
18 words
The method of claim 2 wherein said first gas is hydrogen and said second gas is water vapor.
Claim 14
Dependent Claim
18 words
The method of claim 3 wherein said first gas is hydrogen and said second gas is water vapor.
Claim 15
Dependent Claim
18 words
The method of claim 4 wherein said first gas is hydrogen and said second gas is water vapor.
Claim 16
Dependent Claim
18 words
The method of claim 5 wherein said first gas is hydrogen and said second gas is water vapor.
Claim 17
Independent Claim
126 words
A method for analyzing a gaseous, vaporous or aerosol substance comprising the steps of chemically ionizing said substance in a chemical ionization zone at a chemical ionization pressure in the presence of a first gas comprising at least one selected from the group consisting of hydrogen and charge exchange reactant gases and a second gas comprising a chemical ionization reactant gas, said first and second gases being admixed with said substance in sufficient amount to effect chemical ionization of said substance, and passing the product of said chemical ionization zone into a mass spectrometer through an aperture sufficiently small to maintain a pressure drop between said zone and said mass spectrometer to obtain a mass spectra of the ionized substances formed in said chemical ionization zone.
Claim 18
Independent Claim
126 words
A method for analyzing a gaseous, vaporous or aerosol substance comprising the steps of chemically ionizing said substance in a chemical ionization zone at a chemical ionization pressure in the presence of a first gas comprising at least one selected from the group consisting of hydrogen and charge exchange reactant gases and a second gas comprising a chemical ionization reactant gas, said first and second gases being admixed with said substance in sufficient amount to effect chemical ionization of said substance, and passing the product of said chemical ionization zone into a mass spectrometer through an aperture sufficiently small to maintain a pressure drop between said zone and said mass spectrometer to obtain a mass spectra of the ionized substances formed in said chemical ionization zone.
Claim 19
Dependent Claim
55 words
The method of claim 16 comprising in addition the step of separating said gaseous substance into components in a gas chromatograph before passing the effluent of said chromatograph containing said components and said charge exchange reactant gas from said chromatograph to said chemical ionization zone after adding said chemical ionization reactant gas to said effluent.
Claim 20
Dependent Claim
18 words
The method of claim 16 wherein said first gas is helium and said second gas is water vapor.
Claim 21
Dependent Claim
18 words
The method of claim 17 wherein said first gas is helium and said second gas is water vapor.
Claim 22
Dependent Claim
18 words
The method of claim 16 wherein said first gas is hydrogen and said second gas is water vapor.
Claim 23
Dependent Claim
18 words
The method of claim 17 wherein said first gas is hydrogen and said second gas is water vapor.
Claim 24
Dependent Claim
55 words
The method of claim 1 comprising in addition the step of separating said gaseous substance into components in a gas chromatograph before passing the effluent of said chromatograph containing said components and said charge exchange reactant gas from said chromatograph to said chemical ionization zone after adding said chemical ionization reactant gas to said effluent.
Claim 25
Dependent Claim
55 words
The method of claim 2 comprising in addition the step of separating said gaseous substance into components in a gas chromatograph before passing the effluent of said chromatograph containing said components and said charge exchange reactant gas from said chromatograph to said chemical ionization zone after adding said chemical ionization reactant gas to said effluent.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-25 | 1980-07-26 | 1981-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-25 | 1984-07-26 | 1985-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-25 | 1988-07-26 | 1989-01-25 | $7700.00 | Window Closed / Lapsed |