US4077772A
Expired / Lapsed
US
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Method for the determination of hemoglobin in trace amounts
Assignee: Baxter International Inc
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Filing: 1977-05-31
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Granted: 1978-03-07
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Expires: 1997-05-31
Abstract
Abstract An improved technique for determining the presence of hemoglobin, having increased sensitivity, is provided by bringing the material to be tested into contact with an acidic solution of tetramethylbenzidine and hydrogen peroxide to form a mixture, allowing said mixture to stand for a predetermined period of time, and thereafter examining the mixture for the presence of a colored complex indicative of the presence of hemoglobin. Organic acid is present in a concentration generally of at least 30 percent by volume, to provide a pH of no more than about 2.
Inventors
- 👤 Ulrich C. Geissler
- 👤 William J. Stith
- 👤 Kathleen J. Jewett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:50
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/72; G01N33/721; G01N33/725; Y; Y10; Y10S; Y10S436/00; Y10S436/904
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
81 words
The method of determining the presence of hemoglobin in a material which comprises: bringing said material into contact with an organic acid solution of tetramethylbenzidine and hydrogen peroxide to to form a mixture, allowing said mixture to stand for a predetermined period of time, and examining said mixture for the presence of a green colored complex indicative of the presence of hemoglobin, the improvement comprising: said organic acid being present in said solution concentration of at least 35 percent by volume.
Claim 2
Independent Claim
81 words
The method of determining the presence of hemoglobin in a material which comprises: bringing said material into contact with an organic acid solution of tetramethylbenzidine and hydrogen peroxide to to form a mixture, allowing said mixture to stand for a predetermined period of time, and examining said mixture for the presence of a green colored complex indicative of the presence of hemoglobin, the improvement comprising: said organic acid being present in said solution concentration of at least 35 percent by volume.
Claim 3
Dependent Claim
18 words
The method of claim 1 in which from 0.2 to 3 percent (weight/volume) of hydrogen peroxide is present.
Claim 4
Dependent Claim
22 words
The method of claim 1 in which said acidic solution contains acetic acid at a concentration of essentially 35 to 50 percent.
Claim 5
Dependent Claim
18 words
The method of claim 1 in which the pH of said acidic solution is from 0.8 to 1.5.
Claim 6
Dependent Claim
24 words
The method of claim 1 in which said tetramethylbenzidine is present in said acidic solution in a concentration of 0.05 to 1.5 percent (weight/volume).
Claim 7
Dependent Claim
32 words
The method of claim 1 in which after said predetermined period of time, aqueous solution is added to dilute color and stabilize the reaction by reducing the acid concentration of said solution.
Claim 8
Dependent Claim
43 words
An aqueous solution for determining the presence of hemoglobin in a material which comprises: from 0.05 to 1.5 percent (weight/volume) of tetramethylbenzidine, from 0.2 to 3 percent of hydrogen peroxide, and organic acid in a concentration of 35 to 50 percent by volume.
Claim 9
Dependent Claim
43 words
An aqueous solution for determining the presence of hemoglobin in a material which comprises: from 0.05 to 1.5 percent (weight/volume) of tetramethylbenzidine, from 0.2 to 3 percent of hydrogen peroxide, and organic acid in a concentration of 35 to 50 percent by volume.
Claim 10
Dependent Claim
14 words
The solution of claim 7 in which said pH is from 0.8 to 1.5.
Claim 11
Dependent Claim
20 words
The solution of claim 7 in which said concentration of hydrogen peroxide is essentially from 0.5 to 1 percent (wt./vol.).
Claim 12
Dependent Claim
21 words
The solution of claim 7 in which said tetramethylbenzidine is present in a concentration of about 0.2 to 0.3 percent (wt./vol.).
Claim 13
Independent Claim
90 words
The method of determining the presence of hemoglobin in a material which comprises: bringing said material into contact with an organic acid solution of tetramethylbenzidine and hydrogen peroxide to form a mixture, allowing said mixture to stand for a predetermined period of time, and examining said mixture for the presence of a color complex indicative of the presence of hemoglobin, the improvement comprising: said organic acid being present in a concentration of 30 to 50 percent by volume, there being from 0.2 to 3 percent (wt./vol.) of hydrogen peroxide present.
Claim 14
Independent Claim
90 words
The method of determining the presence of hemoglobin in a material which comprises: bringing said material into contact with an organic acid solution of tetramethylbenzidine and hydrogen peroxide to form a mixture, allowing said mixture to stand for a predetermined period of time, and examining said mixture for the presence of a color complex indicative of the presence of hemoglobin, the improvement comprising: said organic acid being present in a concentration of 30 to 50 percent by volume, there being from 0.2 to 3 percent (wt./vol.) of hydrogen peroxide present.
Claim 15
Dependent Claim
24 words
The method of claim 11 in which said tetramethylbenzidine is present in said acidic solution in a concentration of 0.05 to 1.5 percent (wt./vol.).
Claim 16
Dependent Claim
13 words
The method of claim 12 in which said organic acid is acetic acid.
Claim 17
Dependent Claim
44 words
An aqueous solution for determining the presence of hemoglobin in a material which comprises an organic acid in a concentration of 30 to 50 percent by volume, from 0.2 to 3 percent (wt./vol.) of hydrogen peroxide, and from 0.05 to 1.5 (wt./vol.) of tetramethylbenzidine.
Claim 18
Dependent Claim
44 words
An aqueous solution for determining the presence of hemoglobin in a material which comprises an organic acid in a concentration of 30 to 50 percent by volume, from 0.2 to 3 percent (wt./vol.) of hydrogen peroxide, and from 0.05 to 1.5 (wt./vol.) of tetramethylbenzidine.
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) | 1981-03-06 | 1981-09-05 | 1982-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-06 | 1985-09-05 | 1986-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-06 | 1989-09-05 | 1990-03-07 | $7700.00 | Window Closed / Lapsed |