US4181853A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid chromatography system with packed flow cell for improved fluorescence detection
Assignee: Varian Medical Systems Inc
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Filing: 1978-08-31
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Granted: 1980-01-01
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Expires: 1998-08-31
Abstract
Abstract In a liquid chromatography system, the effluent from the chromatographic column is passed through a detector flow cell, which is packed with a stationary phase that is adsorptive of the sample species to be detected. Detection of the sample species adsorbed at the stationary phase is effected by measuring fluorescence emitted from such species in response to electromagnetic radiation incident thereon at the flow cell. The fluorescing species, which are in equilibrium between the stationary phase and the mobile phase in the flow cell when fluorescence is being measured, can be detected at lower concentration thresholds than when the fluorescing species are in equilibrium only with the mobile phase.
Inventors
- 👤 Ahmad Abu-Shumays
- 👤 Edward L. Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:43
CPC Classifications
G; G01; G01N; G01N30/00; G01N30/02; G01N30/62; G01N30/74; G01N21/00; G01N21/62; G01N21/63; G01N21/64; G01N21/01; G01N21/03; G01N21/0317; G01N21/05
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
85 words
A method for enhancing the fluorescent detectability of an aflatoxin present in a solvent, said method comprising the step of passing an aflatoxin-bearing eluant from a liquid chromatography column through a flow cell packed with aflatoxin-adsorbing particles, whereby there is caused a dynamic equilibrium of the aflatoxin between the solvent of the eluant and said particles, and whereby said detectability is enhanced; said flow cell having a wall portion that is substantially transparent to electromagnetic radiation of a frequency that causes the aflatoxin to fluoresce.
Claim 2
Independent Claim
85 words
A method for enhancing the fluorescent detectability of an aflatoxin present in a solvent, said method comprising the step of passing an aflatoxin-bearing eluant from a liquid chromatography column through a flow cell packed with aflatoxin-adsorbing particles, whereby there is caused a dynamic equilibrium of the aflatoxin between the solvent of the eluant and said particles, and whereby said detectability is enhanced; said flow cell having a wall portion that is substantially transparent to electromagnetic radiation of a frequency that causes the aflatoxin to fluoresce.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein said solvent of the eluant comprises a nonpolar liquid.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein said particles comprise microparticulate silica.
Claim 5
Dependent Claim
10 words
The method of claim 1 wherein said particles comprise alumina.
Claim 6
Dependent Claim
14 words
The method of claim 1 wherein said particles comprise a bonded phase particulate material.
Claim 7
Dependent Claim
12 words
The method of claim 1 wherein said particles comprise an ion-exchange resin.
Claim 8
Dependent Claim
87 words
A chromatographic method for detecting the presence of an aflatoxin in a sample material, said method comprising in sequence the steps of: (a) passing said sample material through a liquid chromatography column; (b) passing the outflow of said column through a flow cell packed with aflatoxin-adsorbing particles whereby there is caused a dynamic equilibrium of the aflatoxin between the mobile phase and said particles; (c) irradiating said flow cell with electromagnetic radiation of a frequency that causes the aflatoxin to fluoresce; and (d) detecting the emitted fluorescence.
Claim 9
Dependent Claim
87 words
A chromatographic method for detecting the presence of an aflatoxin in a sample material, said method comprising in sequence the steps of: (a) passing said sample material through a liquid chromatography column; (b) passing the outflow of said column through a flow cell packed with aflatoxin-adsorbing particles whereby there is caused a dynamic equilibrium of the aflatoxin between the mobile phase and said particles; (c) irradiating said flow cell with electromagnetic radiation of a frequency that causes the aflatoxin to fluoresce; and (d) detecting the emitted fluorescence.
Claim 10
Dependent Claim
14 words
The method of claim 7 wherein said outflow includes at least one nonpolar solvent.
Claim 11
Dependent Claim
11 words
The method of claim 7 wherein said particles comprise microparticulate silica.
Claim 12
Dependent Claim
10 words
The method of claim 7 wherein said particles comprise alumina.
Claim 13
Dependent Claim
14 words
The method of claim 7 wherein said particles comprise a bonded phase particulate material.
Claim 14
Dependent Claim
12 words
The method of claim 7 wherein said particles comprise an ion-exchange resin.
Claim 15
Dependent Claim
24 words
The method of claim 7 wherein said radiation is incident upon said flow cell at approximately right angles to the direction of fluorescence detection.
Claim 16
Dependent Claim
53 words
The method of claim 7 wherein said flow cell of packed with said particles by closing the outlet of said cell with a porous metal plug, injecting a slurry containing said particles into the inlet of said cell, and withdrawing the liquid phase of said slurry from said cell outlet through said plug.
Claim 17
Dependent Claim
16 words
The method of claim 7 wherein a fluorimeter detector is used in detecting said emitted fluorescence.
Claim 18
Dependent Claim
92 words
A fluorescence spectrometer comprising: (a) a flow cell through which an aflatoxin present in a solvent and having been eluted from a liquid chromatography column can pass, said flow cell being packed with aflatoxin-adsorbing particles whereby there is caused a dynamic equilibrium of the aflatoxin between the solvent and said particles; (b) means for irradiating the aflatoxin with electromagnetic radiation of a frequency that causes the aflatoxin to fluoresce; and (c) means for detecting the emitted fluorescence; said flow cell having a wall portion that is substantially transparent to said electromagnetic radiation.
Claim 19
Dependent Claim
92 words
A fluorescence spectrometer comprising: (a) a flow cell through which an aflatoxin present in a solvent and having been eluted from a liquid chromatography column can pass, said flow cell being packed with aflatoxin-adsorbing particles whereby there is caused a dynamic equilibrium of the aflatoxin between the solvent and said particles; (b) means for irradiating the aflatoxin with electromagnetic radiation of a frequency that causes the aflatoxin to fluoresce; and (c) means for detecting the emitted fluorescence; said flow cell having a wall portion that is substantially transparent to said electromagnetic radiation.
Claim 20
Dependent Claim
12 words
The spectrometer of claim 16 wherein said solvent comprises a nonpolar liquid.
Claim 21
Dependent Claim
11 words
The spectrometer of claim 16 wherein said particles comprise microparticulate silica.
Claim 22
Dependent Claim
10 words
The spectrometer of claim 16 wherein said particles comprise alumina.
Claim 23
Dependent Claim
14 words
The spectrometer of claim 16 wherein said particles comprise a bonded phase particulate material.
Claim 24
Dependent Claim
12 words
The spectrometer of claim 16 wherein said particles comprise an ion-exchange resin.
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) | 1982-12-31 | 1983-07-02 | 1984-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-31 | 1987-07-02 | 1988-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-31 | 1991-07-02 | 1992-01-01 | $7700.00 | Window Closed / Lapsed |