US4481296A
Expired / Lapsed
US
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Color indicator system for pH measurement
Assignee: Great Lakes Chemical Corp
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Filing: 1983-02-15
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Granted: 1984-11-06
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Expires: 2003-02-15
Abstract
Abstract A composition comprising phenol red, phenol, and deionized water and preferably sodium hydroxide and citric acid and a method for measuring pH wherein such composition is added to a water sample.
Inventors
- 👤 James L. Halley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:49
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/221; Y; Y10; Y10T; Y10T436/00; Y10T436/25; Y10T436/25125
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
35 words
A stabilized color indicator composition capable of measuring pH in the presence of halogens comprising pheno red, phenol in an amount effective to bind halogens present in a sample to be anaylzed and deionized water.
Claim 2
Dependent Claim
35 words
A stabilized color indicator composition capable of measuring pH in the presence of halogens comprising pheno red, phenol in an amount effective to bind halogens present in a sample to be anaylzed and deionized water.
Claim 3
Dependent Claim
43 words
A composition, as claimed in claim 1, which comprises: from greater than about 0 to about 2 weight percent phenol red; from greater than about 0 to about 10 weight percent phenol; and from about 88 to about 99 weight percent deionized water.
Claim 4
Dependent Claim
12 words
A composition, as claimed in claim 1, which additionally comprises citric acid.
Claim 5
Dependent Claim
12 words
A composition, as claimed in claim 1, which additionally comprises sodium hydroxide.
Claim 6
Dependent Claim
65 words
A composition, as claimed in claim 1, which comprises: from greater than about 0 to about 2 weight percent phenol red; from greater than about 0 to about 10 weight percent phenol; from about 0 to about 1 weight percent sodium hydroxide; from greater than about 0 to about 1 weight percent citric acid; and from about 88 to about 99 weight percent deionized water.
Claim 7
Independent Claim
63 words
A method of measuring pH of an aqueous system comprising the steps of: withdrawing a representative sample from the aqueous system; adding to the representative sample a composition comprising phenol red, phenol in an amount effective to bind halogens present in the sample and deionized water thereby forming an analysis sample; and observing a color change or lack thereof in the representative sample.
Claim 8
Independent Claim
63 words
A method of measuring pH of an aqueous system comprising the steps of: withdrawing a representative sample from the aqueous system; adding to the representative sample a composition comprising phenol red, phenol in an amount effective to bind halogens present in the sample and deionized water thereby forming an analysis sample; and observing a color change or lack thereof in the representative sample.
Claim 9
Dependent Claim
45 words
A method, as claimed in claim 6, wherein the composition comprises: from greater than about 0 to about 2 weight percent phenol red; from greater than about 0 to about 10 weight percent phenol; and from about 88 to about 99 weight percent deionized water.
Claim 10
Dependent Claim
14 words
A method, as claimed in claim 6, wherein the composition additionally comprises citric acid.
Claim 11
Dependent Claim
14 words
A method, as claimed in claim 6, wherein the composition additionally comprises sodium hydroxide.
Claim 12
Dependent Claim
67 words
A method, as claimed in claim 6, wherein the composition comprises: from greater than about 0 to about 2 weight percent phenol red; from greater than about 0 to about 10 weight percent phenol; from about 0 to about 1 weight percent sodium hydroxide; from greater than about 0 to about 1 weight percent citric acid; and from about 88 to about 99 weight percent deionized water.
Claim 13
Dependent Claim
22 words
A method, as claimed in claim 6, wherein the color change is detected by comparing the analysis sample against a color standard.
References Cited (Backward Citations)
US4382122A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-06 | 1988-05-07 | 1988-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-06 | 1992-05-07 | 1992-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-06 | 1996-05-07 | 1996-11-06 | $7700.00 | Window Closed / Lapsed |