US4290772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reducing light scatter in photometric measurements involving suspended particles
Assignee: Rheinmetall Air Defence AG
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Filing: 1979-10-01
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Granted: 1981-09-22
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Expires: 1999-10-01
Abstract
Abstract A method of reducing scattered light during photometric measurements, especially during the photometric measurement of haemoglobin and a reagent for the performance of the method. To a suspension which is ready for a measurement operation there is admixed an additive which reduces the difference between the refractive index of the suspension and the mean refractive index of the suspended phase. The reagent for the photometric determination of the haemoglobin comprises a lysing agent, means for modifying the refractive index, means for stabilizing the leukocytes and a solvent. The reagent is admixed as an additive to a suspension of blood particles in an isotonic solvent.
Inventors
- 👤 Raymond Frey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:21
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/59; Y; Y10; Y10T; Y10T436/00; Y10T436/10; Y10T436/107497; Y10T436/108331
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
93 words
A method of reducing disturbances of photometric measurement due to scattered light in a suspension consisting of a suspension agent and a suspended phase comprising suspended particles, which suspension is to be photometrically measured, said suspension agent and said suspended phase each having a respective refractive index, comprising: adding a chemical component to the suspension, said chemical component having a refractive index outside of the range encompassed by the refractive index of the suspension agent and the mean refractive index of the suspended phase and in a quantity effective to reduce such range.
Claim 2
Independent Claim
93 words
A method of reducing disturbances of photometric measurement due to scattered light in a suspension consisting of a suspension agent and a suspended phase comprising suspended particles, which suspension is to be photometrically measured, said suspension agent and said suspended phase each having a respective refractive index, comprising: adding a chemical component to the suspension, said chemical component having a refractive index outside of the range encompassed by the refractive index of the suspension agent and the mean refractive index of the suspended phase and in a quantity effective to reduce such range.
Claim 3
Dependent Claim
33 words
The method as defined in claim 1, wherein: the suspension is a suspension of haemolysed erythrocytes and stabilised leukocytes in an isotonic common salt solution; and the chemical component is a haemolysing emulsifier.
Claim 4
Dependent Claim
67 words
A reagent for reducing the disturbance due to scattered light of a photometric measurement of a suspension of blood particles in an isotonic suspension agent, said reagent containing: a lysing agent; a first chemical component for modifying the refractive index of the suspension; a second chemical component for stabilizing the leukocytes; and a solvent capable of dissolving said lysing agent and said first and second chemical components.
Claim 5
Dependent Claim
67 words
A reagent for reducing the disturbance due to scattered light of a photometric measurement of a suspension of blood particles in an isotonic suspension agent, said reagent containing: a lysing agent; a first chemical component for modifying the refractive index of the suspension; a second chemical component for stabilizing the leukocytes; and a solvent capable of dissolving said lysing agent and said first and second chemical components.
Claim 6
Dependent Claim
23 words
The reagent as defined in claim 3, wherein said chemical component for modifying the refractive index of said suspension is an haemolysing emulsifier.
Claim 7
Dependent Claim
58 words
The reagent as defined in claim 4, containing: 5 to 10 grams trimethyl tetradecyl ammonium bromide as the lysing agent; 20 to 35 grams octylphenol decaethylene glycol ether as the haemolysing emulsifier; 240 to 350 ml formaldehyde solution comprising 37% by weight formaldehyde in water; and sufficient isotonic sodium chloride solution to make up 1000 ml of reagent.
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) | 1984-09-21 | 1985-03-23 | 1985-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-21 | 1989-03-23 | 1989-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-21 | 1993-03-23 | 1993-09-22 | $7700.00 | Window Closed / Lapsed |