US4670403A
Expired / Lapsed
US
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Method of amino acid analysis
Assignee: Shimadzu Corp
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Filing: 1984-09-11
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Granted: 1987-06-02
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Expires: 2004-09-11
Abstract
Abstract A method of amino acid analysis by reacting an amino acid-containing sample with o-phthalaldehyde and an N-protective group-substituted cysteine such as N-acetyl-L-cysteine under an alkaline condition to yield a fluorescent compound and measuring the intensity of fluorescence or absorbance of the resulting compound. The method is sensitive for quantitative and qualitative analysis of a secondary amino acid such as proline when it is beforehand subjected to an oxidation.
Inventors
- 👤 Yasuo Ishida
- 👤 Michihiko Fujiwara
- 👤 Toshio Kinoshita
- 👤 Noriyuki Nimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:56
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/68; G01N33/6803; G01N33/6806; G01N33/6812; G01N33/6815; G01N33/6809
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
71 words
A method of amino acid analysis which comprises (1) subjecting an amino acid-containing sample to liquid chromatography, thereby providing a separated amino acid phase, (2) treating the separated amino acid phase with an oxidizer to obtain an oxidized-amino acid phase, (3) treating said oxidized-amino acid phase with o-phthalaldehyde and N-acetyl-L-cysteine under an alkaline condition to yield a fluorescent compound, and (4) measuring intensity of fluorescence or absorbance of the fluorescent compound.
Claim 2
Independent Claim
71 words
A method of amino acid analysis which comprises (1) subjecting an amino acid-containing sample to liquid chromatography, thereby providing a separated amino acid phase, (2) treating the separated amino acid phase with an oxidizer to obtain an oxidized-amino acid phase, (3) treating said oxidized-amino acid phase with o-phthalaldehyde and N-acetyl-L-cysteine under an alkaline condition to yield a fluorescent compound, and (4) measuring intensity of fluorescence or absorbance of the fluorescent compound.
Claim 3
Dependent Claim
18 words
The method of claim 1 in which the amino acid-containing sample is one containing a primary amino acid.
Claim 4
Dependent Claim
33 words
The method of claim 1 wherein the amino acid-containing sample is a secondary amino acid-containing sample wherein said secondary amino acid is selected from the group consisting of proline and N-lower alkyl-substituted glycine.
Claim 5
Dependent Claim
22 words
The method of claim 1 in which step (3) is conducted in an alkaline buffer having a pH of 9 to 12.
Claim 6
Dependent Claim
20 words
The method of claim 4 in which the alkaline buffer is a borate type, carbonate type or borate-carbonate type buffer.
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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) | 1990-06-01 | 1990-12-01 | 1991-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-01 | 1994-12-01 | 1995-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-01 | 1998-12-01 | 1999-06-02 | $7700.00 | Window Closed / Lapsed |