Patent US4092115A successfully refreshed from Google Patents.
US4092115A
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Method, device and test reagent for detecting free available chlorine in aqueous fluids
Assignee: Hach Co
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Filing: 1977-05-20
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Granted: 1978-05-30
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Expires: 1997-05-20
Abstract
Abstract A method, device and test reagent for detecting free available chlorine in aqueous fluids which utilizes as an indicator substance azine compounds of the formula: <IMAGE> where R and R' are hydroxy or amino substituents and X, X', Y and Y' are hydrogen, hydroxy, methyl or methoxy substituents and may be the same or different. Preferably such test reagents are incorporated with a carrier member or with a wicking device for concentrating the aqueous fluid being tested in the area of the test reagent.
Inventors
- 👤 Chauncey Orvis Rupe
- 👤 Robert Bauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:49
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/18; G01N33/182; G01N31/00; G01N31/22; Y; Y10; Y10T; Y10T436/00; Y10T436/19; Y10T436/193333
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
116 words
A method for detecting only free available chlorine in an aqueous fluid suspected of containing both free and combined available chlorine which comprises contacting the fluid with a test reagent comprising an indicator substance selected from the group consisting of (1) a compound having the formula ##STR3## where R and R' are selected from the group consisting of hydroxy and amino groups and X, X', Y and Y' are selected from the group consisting of hydrogen, hydroxy, methyl and methoxy groups and (2) combinations thereof, and a buffer for adjusting the pH of the test reagent to about from 3.5 to 8.5; and comparing the color obtained with colors obtained using standard chlorine containing aqueous fluids.
Claim 2
Independent Claim
116 words
A method for detecting only free available chlorine in an aqueous fluid suspected of containing both free and combined available chlorine which comprises contacting the fluid with a test reagent comprising an indicator substance selected from the group consisting of (1) a compound having the formula ##STR3## where R and R' are selected from the group consisting of hydroxy and amino groups and X, X', Y and Y' are selected from the group consisting of hydrogen, hydroxy, methyl and methoxy groups and (2) combinations thereof, and a buffer for adjusting the pH of the test reagent to about from 3.5 to 8.5; and comparing the color obtained with colors obtained using standard chlorine containing aqueous fluids.
Claim 3
Dependent Claim
15 words
A method as in claim 1 wherein the pH of the test reagent is 6.0.
Claim 4
Dependent Claim
12 words
A method as in claim 1 wherein the indicator substance comprises syringaldazine.
Claim 5
Dependent Claim
17 words
A method as in claim 1 wherein the indicator substance is a combination of syringaldazine and vanillinazine.
Claim 6
Dependent Claim
16 words
A method as in claim 1 wherein the test reagent is incorporated with a carrier member.
Claim 7
Dependent Claim
24 words
A method as in claim 5 wherein the carrier member is bibulous paper and the test reagent is impregnated into or onto said paper.
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) | 1981-05-29 | 1981-11-28 | 1982-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-29 | 1985-11-28 | 1986-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-29 | 1989-11-28 | 1990-05-30 | $7700.00 | Window Closed / Lapsed |