US4252903A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Indicator-capillary for urea-determination
Assignee: Individual
•
Filing: 1978-11-03
•
Granted: 1981-02-24
•
Expires: 1998-11-03
Abstract
Abstract An indicator for urea determination has a capillary tube provided on the inside with an indicator-signal band in form of stripe-shaped signal zones treated with a dyestuff which changes color in the alkaline range; there are untreated spaces between the stripe-shaped signal zones. The lower end of the capillary tube has a colored mark to indicate the level to which it is to be filled.
Inventors
- 👤 Karl-Heinz Kallies
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:55
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/52; G01N33/521; G01N33/523; C; C12; C12Q; C12Q1/00; C12Q1/58; Y; Y10; Y10S; Y10S435/00; Y10S435/805; Y10S435/81
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
126 words
An indicator capillary for urea determination, comprising a capillary tube of glass or plastic having an internal diameter of from about 1 to 3 mm and a length of from about 40 to 120 mm; an indicator signal-band of natural or synthetic fibers inside said capillary tube, said indicator signal-band containing an unbuffered, alkali-carbonate and alkali-hydroxide-free reaction system of slightly purified urease and about 1 to 15% of a saccharide or polysaccharide, said indicator signalband having one or more stripe-shaped indicator signal zones treated with a dyestuff indicator which changes color in the alkaline range and also having untreated spaces between said signal zones; and a colored mark on a lower end portion of the capillary tube to indicate the intended filling level of the tube.
Claim 2
Dependent Claim
126 words
An indicator capillary for urea determination, comprising a capillary tube of glass or plastic having an internal diameter of from about 1 to 3 mm and a length of from about 40 to 120 mm; an indicator signal-band of natural or synthetic fibers inside said capillary tube, said indicator signal-band containing an unbuffered, alkali-carbonate and alkali-hydroxide-free reaction system of slightly purified urease and about 1 to 15% of a saccharide or polysaccharide, said indicator signalband having one or more stripe-shaped indicator signal zones treated with a dyestuff indicator which changes color in the alkaline range and also having untreated spaces between said signal zones; and a colored mark on a lower end portion of the capillary tube to indicate the intended filling level of the tube.
Claim 3
Dependent Claim
24 words
The indicator-capillary of claim 1, further comprising an enlarged reaction room inside said capillary tube with an interior diameter up to about 10 mm.
Claim 4
Dependent Claim
24 words
The indicator-capillary of claim 1, wherein said capillary tube has an internal diameter of about 2.5 mm and a length of about 60 mm.
Claim 5
Dependent Claim
25 words
The indicator-capillary of claim 1, wherein said indicator signalband is made from filter paper of a weight from about 60 to 400 g/m 2 .
Claim 6
Dependent Claim
10 words
The indicator-capillary of claim 1, wherein said saccharide is glucose.
Claim 7
Dependent Claim
12 words
The indicator-capillary of claim 1, wherein said dyestuff indicator is brilliant yellow.
Claim 8
Dependent Claim
36 words
The indicator capillary of claim 1, wherein said stripe-shaped indicator signal zones have a width of from about 1 to 5 mm and the untreated spaces have a width of from about 1 to 10 mm.
Claim 9
Dependent Claim
17 words
The indicator-capillary of claim 7, wherein said stripe-shaped indicator signalzones have a width of about 2 mm.
References Cited (Backward Citations)
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US3884641A
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US3950226A
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US4066403A
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US4094647A
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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) | 1984-02-24 | 1984-08-25 | 1985-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-24 | 1988-08-25 | 1989-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-24 | 1992-08-25 | 1993-02-24 | $7700.00 | Window Closed / Lapsed |