US4248973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capillary tube indicator for the determination of urea concentrations
Assignee: Teva GmbH
•
Filing: 1978-12-22
•
Granted: 1981-02-03
•
Expires: 1998-12-22
Abstract
Abstract A capillary tube indicator for determination of urea concentrations, which permits a simple measurement of the sample without auxiliary aids, provides an easily readable measurement, and does not require the addition of buffers, alkali carbonates or hydroxides. The indicator includes a capillary tube of glass or plastic into which a specially prepared indicator strip is inserted. The reaction system of the indicator strip includes a partially purified urease preparation and 1 to 15% of a saccharide or polysaccharide, preferably glucose. The indicator strip also has zones treated with alkali-sensitive dye, applied so as to give either quantitative or semiquantitative readings of urea concentration.
Inventors
- 👤 Karl-Heinz Kallies
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:36
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: 13
Claim 1
Independent Claim
119 words
A capillary tube indicator for the micro determination of urea concentrations comprising a capillary tube having a marking line near one end to indicate sample level; an indicator strip inserted within said capillary tube; a reaction system applied in a zone at one end of said indicator strip comprising a partially purified urease preparation and between substantially 1 and 15% of a saccharide or polysaccharide; and above said reaction system zone at least one indicator dye sensitive to alkali applied to said indicator strip in a plurality of zones for providing a visual indication of the urea concentration with untreated bands of the indicator strip separating said indicator zones and said reaction system zone from said first indicator zone.
Claim 2
Dependent Claim
119 words
A capillary tube indicator for the micro determination of urea concentrations comprising a capillary tube having a marking line near one end to indicate sample level; an indicator strip inserted within said capillary tube; a reaction system applied in a zone at one end of said indicator strip comprising a partially purified urease preparation and between substantially 1 and 15% of a saccharide or polysaccharide; and above said reaction system zone at least one indicator dye sensitive to alkali applied to said indicator strip in a plurality of zones for providing a visual indication of the urea concentration with untreated bands of the indicator strip separating said indicator zones and said reaction system zone from said first indicator zone.
Claim 3
Dependent Claim
15 words
An indicator as defined in claim 1, wherein said capillary tube is glass or plastic.
Claim 4
Dependent Claim
32 words
An indicator as defined in claim 1, wherein said capillary tube has a length of between substantially 40 and 120 mm and an inner diameter of between substantially 1 and 3 mm.
Claim 5
Dependent Claim
24 words
An indicator as defined in claim 1, wherein said capillary tube has a length of 6 mm and an inner diameter of 2.5 mm.
Claim 6
Dependent Claim
24 words
An indicator as defined in claim 1, wherein said capillary tube has a portion having an expanded inner diameter of up to 10 mm.
Claim 7
Dependent Claim
17 words
An indicator as defined in claim 1, wherein said indicator strip is of natural or synthetic fiber.
Claim 8
Dependent Claim
26 words
An indicator as defined in claim 1, wherein said indicator strip is of filter paper having a weight of substantially 60 to 400 g/m 2 .
Claim 9
Dependent Claim
14 words
An indicator as defined in claim 1, wherein said saccharide or polysaccharide is glucose.
Claim 10
Dependent Claim
13 words
An indicator as defined in claim 1, wherein said indicator dye is brilliant-yellow.
Claim 11
Dependent Claim
15 words
An indicator tube as defined in claim 1, wherein said indicator dye is bromocresol green.
Claim 12
Dependent Claim
37 words
An indicator tube as defined in claim 1, wherein said indicator dye zones have a width of between substantially 1 to 5 mm, and said untreated zones have a width of between substantially 1 to 10 mm.
Claim 13
Dependent Claim
18 words
An indicator as defined in claim 11, wherein said indicator dye zones have a width of 2 mm.
References Cited (Backward Citations)
US3249513A
Cited
US3768978A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-03 | 1984-08-04 | 1985-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-03 | 1988-08-04 | 1989-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-03 | 1992-08-04 | 1993-02-03 | $7700.00 | Window Closed / Lapsed |