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US4176008A
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Method, composition and element for the detection of nitrogen-containing compounds
Assignee: Eastman Kodak Co
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Filing: 1978-02-24
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Granted: 1979-11-27
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Expires: 1998-02-24
Abstract
Abstract Methods, compositions and elements for detecting a nitrogen-containing compound capable of releasing ammonia upon enzymatic action are described. The method comprises contacting in an aqueous medium a sample suspected of containing such a compound and a novel assay composition comprising at least one enzyme which catalyzes the decomposition of the compound to ammonia and detecting the ammonia by condensation with a diketone and measuring the color or fluorescence produced by the resulting dihydropyridine. The foregoing assay composition can be incorporated into single-layer or multilayer analytical elements of the type known in the prior art. A preferred such element comprises an isotropically porous spreading layer in fluid contact with a reagent layer. The spreading layer is most preferably non-fibrous.
Inventors
- 👤 John Figueras
- 👤 Roger W. Nelson
- 👤 Richard C. Sutton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:29
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/58
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
111 words
An element for the determination in an aqueous sample of nitrogen-containing analyte capable of releasing ammonia upon enzymatic action, said element comprising a spreading layer and a reagent layer in fluid contact and containing (a) at least one enzyme which catalyzes the decomposition of the analyte to ammonia, and (b) a diketone of the formula ##STR5## wherein R 1 , R 2 , R 3 and R 4 are the same or different, and are each hydrogen, aryl of from 6 to 20 carbon atoms, a straight- or branched-chain alkyl or aralkyl of up to about 20 carbon atoms, or a cycloalkyl of from about 5 to about 7 carbon atoms.
Claim 2
Dependent Claim
111 words
An element for the determination in an aqueous sample of nitrogen-containing analyte capable of releasing ammonia upon enzymatic action, said element comprising a spreading layer and a reagent layer in fluid contact and containing (a) at least one enzyme which catalyzes the decomposition of the analyte to ammonia, and (b) a diketone of the formula ##STR5## wherein R 1 , R 2 , R 3 and R 4 are the same or different, and are each hydrogen, aryl of from 6 to 20 carbon atoms, a straight- or branched-chain alkyl or aralkyl of up to about 20 carbon atoms, or a cycloalkyl of from about 5 to about 7 carbon atoms.
Claim 3
Dependent Claim
9 words
The element of claim 1 further comprising a buffer.
Claim 4
Dependent Claim
22 words
The element of claim 1 further comprising a buffer to maintain the pH of the composition between about 4.5 and about 6.5.
Claim 5
Dependent Claim
18 words
The element of claim 2 wherein the buffer maintains the pH at from about 5.9 to about 6.1.
Claim 6
Dependent Claim
20 words
The element of claim 2 wherein the buffer is selected from the group consisting of acetic acid and citric acid.
Claim 7
Dependent Claim
11 words
The element of claim 1 wherein the diketone is methylenebis(acetoacetic ester).
Claim 8
Dependent Claim
10 words
The element of claim 1 wherein the enzyme is urease.
Claim 9
Dependent Claim
96 words
A composition for the detection in an aqueous sample containing analyte capable of releasing ammonia upon enzymatic action, said composition comprising at least one enzyme which catalyzes the decomposition of the analyte to ammonia, and a diketon of the formula ##STR6## wherein R 1 , R 2 , R 3 and R 4 are the same or different, and are each hydrogen, aryl of from 6 to 20 carbon atoms, a straight- or branched-chain alkyl or aralkyl of up to about 20 carbon atoms, or a cycloalkyl of from about 5 to about 7 carbon atoms.
Claim 10
Dependent Claim
96 words
A composition for the detection in an aqueous sample containing analyte capable of releasing ammonia upon enzymatic action, said composition comprising at least one enzyme which catalyzes the decomposition of the analyte to ammonia, and a diketon of the formula ##STR6## wherein R 1 , R 2 , R 3 and R 4 are the same or different, and are each hydrogen, aryl of from 6 to 20 carbon atoms, a straight- or branched-chain alkyl or aralkyl of up to about 20 carbon atoms, or a cycloalkyl of from about 5 to about 7 carbon atoms.
Claim 11
Dependent Claim
9 words
The composition of claim 8 further comprising a buffer.
Claim 12
Dependent Claim
22 words
The composition of claim 8 further comprising a buffer to maintain the pH of the composition between about 4.5 and about 6.5.
Claim 13
Dependent Claim
21 words
The composition of claim 9 wherein the buffer maintains the pH of the composition at from about 5.9 to about 6.1.
Claim 14
Dependent Claim
20 words
The composition of claim 9 wherein the buffer is selected from the group consisting of acetic acid and citric acid.
Claim 15
Dependent Claim
11 words
The composition of claim 8 wherein the diketone is methylenebis(acetoacetic ester).
Claim 16
Dependent Claim
77 words
A composition for the detection of urea in an aqueous sample said composition comprising urease and a diketone of the formula ##STR7## wherein R 1 , R 2 , R 3 and R 4 are the same or different, and are each hydrogen, aryl of from 6 to 20 carbon atoms, a straight- or branched-chain alkyl or aralkyl of up to about 20 carbon atoms, or a cycloalkyl of from about 5 to about 7 carbon atoms.
Claim 17
Dependent Claim
77 words
A composition for the detection of urea in an aqueous sample said composition comprising urease and a diketone of the formula ##STR7## wherein R 1 , R 2 , R 3 and R 4 are the same or different, and are each hydrogen, aryl of from 6 to 20 carbon atoms, a straight- or branched-chain alkyl or aralkyl of up to about 20 carbon atoms, or a cycloalkyl of from about 5 to about 7 carbon atoms.
Claim 18
Dependent Claim
9 words
The composition of claim 14 further comprising a buffer.
Claim 19
Dependent Claim
25 words
The composition of claim 14 further comprising a buffer to maintain the pH of the composition at a pH of between 4.5 and about 6.5.
Claim 20
Dependent Claim
21 words
The composition of claim 16 wherein the buffer maintains the pH of the composition at from about 5.9 to about 6.1.
Claim 21
Dependent Claim
20 words
The composition of claim 15 wherein the buffer is selected from the group consisting of acetic acid and citric acid.
Claim 22
Dependent Claim
11 words
The composition of claim 14 wherein the diketone is methylenebis(acetoacetic ester).
Claim 23
Independent Claim
123 words
A method for the detection of nitrogen-containing analyte capable of releasing ammonia upon enzymatic action comprising the steps of: (a) contacting in an aqueous medium a sample suspected of containing such analyte and an assay composition comprising at least one enzyme which catalyzes the decomposition of the analyte to ammonia and a diketone of the formula ##STR8## wherein R 1 , R 2 , R 3 and R 4 are the same or different and are each hydrogen, aryl of from 6 to 20 carbon atoms, a straight- or branched-chain alkyl or aralkyl of up to about 20 carbon atoms, or a cycloalkyl of from about 5 to about 7 carbon atoms; and (b) detecting any color or fluorescence produced in step (a).
Claim 24
Independent Claim
123 words
A method for the detection of nitrogen-containing analyte capable of releasing ammonia upon enzymatic action comprising the steps of: (a) contacting in an aqueous medium a sample suspected of containing such analyte and an assay composition comprising at least one enzyme which catalyzes the decomposition of the analyte to ammonia and a diketone of the formula ##STR8## wherein R 1 , R 2 , R 3 and R 4 are the same or different and are each hydrogen, aryl of from 6 to 20 carbon atoms, a straight- or branched-chain alkyl or aralkyl of up to about 20 carbon atoms, or a cycloalkyl of from about 5 to about 7 carbon atoms; and (b) detecting any color or fluorescence produced in step (a).
Claim 25
Dependent Claim
12 words
The method of claim 20, wherein said composition further comprises a buffer.
Claim 26
Dependent Claim
29 words
The method of claim 20, wherein said composition further comprises a buffer to maintain the pH of the composition at a pH of between about 4.5 and about 6.5.
Claim 27
Dependent Claim
26 words
The method of claim 20 wherein said composition further comprises a buffer to maintain the pH of the composition at from about 5.9 to about 6.1.
Claim 28
Dependent Claim
20 words
The method of claim 21 wherein the buffer is selected from the group consisting of acetic acid and citric acid.
Claim 29
Dependent Claim
11 words
The method of claim 20 wherein the diketone is methylenebis(acetoacetic ester).
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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) | 1982-11-26 | 1983-05-28 | 1983-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-26 | 1987-05-28 | 1987-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-26 | 1991-05-28 | 1991-11-27 | $7700.00 | Window Closed / Lapsed |