US3924950A
Expired / Lapsed
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Atomic absorption spectroscopy with background correction
Assignee: Applied Biosystems Inc
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Filing: 1974-09-16
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Granted: 1975-12-09
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Expires: 1994-09-16
Abstract
Abstract An atomic absorption spectrometer which combines the advantages of double beam background correction, continuous source lamp operation, insensitivity to sample region emission, and inexpensive construction, includes a fixed beam splittercombiner, combines radiation from a line source with that from a deuterium or hydrogen source and simultaneously splits the combined radiation into sample and reference beams. These beams are chopped ahead of the sample region and are recombined beyond the sample region by a second beam splitter-combiner. The recombined beam then goes through a monochromator and onto a detector. The resulting signal is analyzed electronically to yield background and spectral line intensities in both the sample and reference beams.
Inventors
- 👤 Jr E Horace Siegler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:14
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/3103
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
157 words
An atomic absorption spectrometer which comprises: means for forming a first beam containing substantially monochromatic radiation comprising a wavelength of interest; means for forming a second beam of pulsed nonmonochromatic radiation which includes said wavelength of interest; a first beam splitter for combining the radiation of said first and second beams, splitting the combined radiation into a sample beam and a reference beam and directing them, respectively, through a sample region and a reference region; means for chopping said sample and reference beams prior to their entering said sample and reference regions; a second beam splitter for receiving and recombining said chopped beams after their leaving said sample and reference regions; means for isolating from said recombined beam a relatively narrow wavelength region containing the wavelength of interest; and means for measuring the intensity of said isolated wavelength region at periods established by the pulse rate of said second beam and the frequency of said chopping means.
Claim 2
Dependent Claim
157 words
An atomic absorption spectrometer which comprises: means for forming a first beam containing substantially monochromatic radiation comprising a wavelength of interest; means for forming a second beam of pulsed nonmonochromatic radiation which includes said wavelength of interest; a first beam splitter for combining the radiation of said first and second beams, splitting the combined radiation into a sample beam and a reference beam and directing them, respectively, through a sample region and a reference region; means for chopping said sample and reference beams prior to their entering said sample and reference regions; a second beam splitter for receiving and recombining said chopped beams after their leaving said sample and reference regions; means for isolating from said recombined beam a relatively narrow wavelength region containing the wavelength of interest; and means for measuring the intensity of said isolated wavelength region at periods established by the pulse rate of said second beam and the frequency of said chopping means.
Claim 3
Dependent Claim
12 words
The spectrometer of claim 1 wherein said isolating means comprises a monochromator.
Claim 4
Dependent Claim
12 words
The spectrometer of claim 1 wherein said first beam is substantially continuous.
Claim 5
Dependent Claim
13 words
The spectrometer of claim 1 wherein said chopping means comprises an opaque chopper.
Claim 6
Dependent Claim
38 words
The spectrometer of claim 4 wherein said opaque chopper is arranged to repetitively and sequentially: block both the sample and reference beams; pass one of said beams; block both said beams; and pass the other of said beams.
Claim 7
Dependent Claim
33 words
The spectrometer of claim 5 wherein said pulsed radiation forming means causes said radiation to pulse on during periods when both beams are blocked and off during periods when one beam is passed.
Claim 8
Dependent Claim
12 words
The spectrometer of claim 6 wherein said first beam is substantially continuous.
Claim 9
Independent Claim
159 words
The method of performing atomic absorption spectroscopy which comprises: forming a first beam containing substantially monochromatic radiation comprising a wavelength of interest; forming a second beam of pulsed nonmonochromatic radiation which includes said wavelength of interest and which contains wavelengths adjacent said wavelength of interest combining the radiation of said first and second beams; splitting the combined radiation into a sample beam and a reference beam; directing the sample and reference beams, respectively, through sample and reference regions; chopping said sample and reference beams prior to their entering said sample and reference regions; recombining the chopped beams after their leaving said sample and reference regions; isolating from the recombined beam a relatively narrow wavelength region containing the wavelength of interest; measuring the intensity of the isolated wavelength region at periods established by the pulse rate of the second beam and the chopping frequency; and computing therefrom the background and spectral line intensities in both the sample and reference beams.
Claim 10
Independent Claim
159 words
The method of performing atomic absorption spectroscopy which comprises: forming a first beam containing substantially monochromatic radiation comprising a wavelength of interest; forming a second beam of pulsed nonmonochromatic radiation which includes said wavelength of interest and which contains wavelengths adjacent said wavelength of interest combining the radiation of said first and second beams; splitting the combined radiation into a sample beam and a reference beam; directing the sample and reference beams, respectively, through sample and reference regions; chopping said sample and reference beams prior to their entering said sample and reference regions; recombining the chopped beams after their leaving said sample and reference regions; isolating from the recombined beam a relatively narrow wavelength region containing the wavelength of interest; measuring the intensity of the isolated wavelength region at periods established by the pulse rate of the second beam and the chopping frequency; and computing therefrom the background and spectral line intensities in both the sample and reference beams.
Claim 11
Dependent Claim
12 words
The method of claim 8 wherein said first beam is substantially continuous.
Claim 12
Dependent Claim
35 words
The method of claim 8 wherein said chopping is in the sequence: block both the sample and reference beams; pass one of said beams; block both said beams; and pass the other of said beams.
Claim 13
Dependent Claim
27 words
The method of claim 10 wherein said nonmonochromatic radiation pulses on during periods when both beams are blocked and off during periods when one beam is passed.
Claim 14
Dependent Claim
12 words
The method of claim 11 wherein said first beam is substantially continuous.
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) | 1978-12-08 | 1979-06-09 | 1979-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-08 | 1983-06-09 | 1983-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-08 | 1987-06-09 | 1987-12-09 | $7700.00 | Window Closed / Lapsed |