US3567374A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Urea determination
Assignee: Dow Chemical Co
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Filing: 1968-07-24
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Granted: 1971-03-02
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Expires: 1988-07-24
Abstract
Abstract A REAGENT FOR THE DETERMINATION OF UREA NITROGEN IN BIOLOGICAL FLUIDS USING THE DIACETYL MONOXIME COLOR REACTION IS PREPARED BY DISSOLVING THIOSEMICARBAZIDE, A LINEARITY-ENHANCING AMOUNT OF UREA AND A STABILIZING AMOUNT OF A METAL SALT, PREFERABLY CADMIUM SULFATE, IN A MIXTURE OF PHOSPHORIC ACID AND SULFURIC ACID. THE REAGENT HAS IMPROVED LINEARITY, STABILITY, PHOTOSENSITIVITY AND SPECIFICITY PROPERTIES. METHODS OF PREPARING THE REAGENT AND USING IT IN THE DETERMINATION OF UREA NITROGEN ARE DISCLOSED.
Inventors
- 👤 Donald R Wybenga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:20
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/62; Y; Y10; Y10T; Y10T436/00; Y10T436/17; Y10T436/171538
Claims Analysis
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References Cited (Backward Citations)
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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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |