US4211531A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Colorimetric cholesterol assay
Assignee: Sigma-Aldrich Co LLC
•
Filing: 1979-04-20
•
Granted: 1980-07-08
•
Expires: 1999-04-20
Abstract
Abstract A total cholesterol method includes the steps of (1) precipitation of serum proteins with a reagent containing ferric chloride in propionic acid, (2) color formation by heating aliquots of supernatant with propionic-sulfuric acid reagent, and (3) measurement of color intensities of test and standard reaction mixtures at 563 nm.
Inventors
- 👤 Manik L. Das
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 02:47
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/92; G01N2800/00; G01N2800/04; G01N2800/044
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
79 words
In a method of determining cholesterol in a biological sample comprising a precipitation step for precipitating protein in the sample, a color forming step for forming in the resulting supernatant a color proportional to the concentration of at least one form of cholesterol in the sample, and a step of determining the depth of color formed, the improvement wherein said precipitation step is carried out by means of a reagent comprising colorimetric amounts of propionic acid and ferric ion.
Claim 2
Dependent Claim
79 words
In a method of determining cholesterol in a biological sample comprising a precipitation step for precipitating protein in the sample, a color forming step for forming in the resulting supernatant a color proportional to the concentration of at least one form of cholesterol in the sample, and a step of determining the depth of color formed, the improvement wherein said precipitation step is carried out by means of a reagent comprising colorimetric amounts of propionic acid and ferric ion.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said biological sample is human serum.
Claim 4
Dependent Claim
26 words
The method of claim 1 wherein said color forming step is carried out in a solution containing a colorimetric amount of sulfuric acid and propionic acid.
Claim 5
Dependent Claim
74 words
In a method of determining cholesterol in a biological sample comprising a color forming step of forming a reaction mixture including at least a fraction of said serum and a color forming reagent and thereafter a step of relating the depth of color formed to the amount of at least one form of cholesterol in said reaction mixture, the improvement wherein said reaction mixture contains a colorimetric amount of sulfuric acid and propionic acid.
Claim 6
Dependent Claim
74 words
In a method of determining cholesterol in a biological sample comprising a color forming step of forming a reaction mixture including at least a fraction of said serum and a color forming reagent and thereafter a step of relating the depth of color formed to the amount of at least one form of cholesterol in said reaction mixture, the improvement wherein said reaction mixture contains a colorimetric amount of sulfuric acid and propionic acid.
Claim 7
Dependent Claim
12 words
The method of claim 4 wherein said biological sample is human serum.
Claim 8
Dependent Claim
17 words
The method of claim 5 wherein said reaction mixture further comprises a colorimetric amount of ferric ion.
Claim 9
Independent Claim
95 words
A method of determining cholesterol in a sample of human serum, said method comprising a first step of precipitating protein in said sample by means of a protein precipitation reagent comprising colorimetric amounts of propionic acid and ferric ion, to produce a generally protein-free supernatant, a second step of developing color in a reaction mixture comprising said supernatant and a cholesterol color reagent, said cholesterol color reagent comprising colorimetric amounts of propionic acid and sulfuric acid, and a third step of relating the depth of color formed to the amount of cholesterol in said sample.
Claim 10
Independent Claim
95 words
A method of determining cholesterol in a sample of human serum, said method comprising a first step of precipitating protein in said sample by means of a protein precipitation reagent comprising colorimetric amounts of propionic acid and ferric ion, to produce a generally protein-free supernatant, a second step of developing color in a reaction mixture comprising said supernatant and a cholesterol color reagent, said cholesterol color reagent comprising colorimetric amounts of propionic acid and sulfuric acid, and a third step of relating the depth of color formed to the amount of cholesterol in said sample.
Claim 11
Dependent Claim
29 words
The method of claim 7 wherein said protein precipitation reagent consists essentially of from about 0.5 to about 2.5 grams per liter of ferric chloride dissolved in propionic acid.
Claim 12
Dependent Claim
33 words
The method of claim 8 wherein said cholesterol color reagent consists essentially of sulfuric acid and propionic acid, said sulfuric acid constituting from 20% to 60% of said cholesterol color reagent by volume.
Claim 13
Dependent Claim
40 words
The method of claim 8 wherein said second (color development) step includes heating said reaction mixture to a temperature of from about 50° C. to about 100° C. for a period of from about thirty seconds to about two minutes.
Claim 14
Dependent Claim
41 words
A reagent kit for determination of total cholesterol, said reagent kit comprising a first container containing a colorimetric amount of ferric chloride and propionic acid and a second container containing a reagent comprising colorimetric amount of propionic acid and sulfuric acid.
Claim 15
Dependent Claim
41 words
A reagent kit for determination of total cholesterol, said reagent kit comprising a first container containing a colorimetric amount of ferric chloride and propionic acid and a second container containing a reagent comprising colorimetric amount of propionic acid and sulfuric acid.
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) | 1983-07-08 | 1984-01-07 | 1984-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-07-08 | 1988-01-07 | 1988-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-07-08 | 1992-01-07 | 1992-07-08 | $7700.00 | Window Closed / Lapsed |