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US4960711A
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Method for the quantitative determination of trihalomethanes
Assignee: Fuji Electric Co Ltd
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Filing: 1989-01-30
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Granted: 1990-10-02
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Expires: 2009-01-30
Abstract
Abstract An apparatus for quantitative determination of trihalomethanes comprises a separation unit containing two channels in contact with each other via a microporous membrane that will not react with trihalomethanes, a reaction unit for heating a carrier solution that has passed through the separation unit, a cooling unit for cooling the carrier solution that has undergone complete reaction; and a detection unit for determining the quantity of a fluorescent substance in the carrier solution. A method for quantitative determination of trihalomethanes comprises flowing a sample solution or a mixture thereof with a reducing agent through one of the two channels in the separation unit, flowing the carrier solution through the other channel, heating the carrier solution that has passed through the separation unit and to which an alkaline nicotinamide or a derivative thereof has been added, cooling the carrier solution, and subjecting the cooled solution to fluorimetry.
Inventors
- 👤 Toyoaki Aoki
- 👤 Kouji Kawakami
- 👤 Yoshiharu Tanaka
- 👤 Hiroshi Hoshikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:39
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/18; G01N33/1826; G01N31/00; G01N31/16; G01N31/166; G01N31/22; G01N35/00; G01N35/08; G01N35/085; Y; Y10; Y10T; Y10T436/00; Y10T436/11; Y10T436/117497; Y10T436/118339; Y10T436/19; Y10T436/193333; Y10T436/196666; Y10T436/25; Y10T436/25125; Y10T436/25375; Y10T436/255
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
136 words
A method for determining a quantity of trihalomethanes present in a sample containing interfering substances, comprising the steps of: flowing a sample solution through a first channel in a membrane separator; flowing a carrier solution through a second channel in the membrane separator, the first and the second channels being in contact with each other via pores of a microporous membrane that will not react with the trihalomethanes present, the bores having a size sufficient to filter at least a portion of the interfering substances and to allow pressure of the trihalomethanes; heating the carrier solution that has passed through the membrane separator and to which an alkaline nicotinamide or a derivative thereof has been added; cooling the carrier solution; and determining the quantity of trihalomethanes in the solution by subjecting the cooled solution to fluorimetry.
Claim 2
Independent Claim
136 words
A method for determining a quantity of trihalomethanes present in a sample containing interfering substances, comprising the steps of: flowing a sample solution through a first channel in a membrane separator; flowing a carrier solution through a second channel in the membrane separator, the first and the second channels being in contact with each other via pores of a microporous membrane that will not react with the trihalomethanes present, the bores having a size sufficient to filter at least a portion of the interfering substances and to allow pressure of the trihalomethanes; heating the carrier solution that has passed through the membrane separator and to which an alkaline nicotinamide or a derivative thereof has been added; cooling the carrier solution; and determining the quantity of trihalomethanes in the solution by subjecting the cooled solution to fluorimetry.
Claim 3
Dependent Claim
19 words
A method according to claim 1, further comprising the step of mixing a reducing agent with the sample solution.
Claim 4
Dependent Claim
43 words
A method according to claim 1, wherein sodium hydroxide is added to the carrier solution before the carrier solution enters into the second channel and a nicotinamide solution is added to the carrier solution after the carrier solution exits from the second channel.
Claim 5
Dependent Claim
39 words
A method according to claim 1, wherein the carrier solution is distilled water or ion-exhanger water, and a nicotinamide solution and a hydroxide solution are added to the carrier solution after the carrier solution exits from the second channel.
Claim 6
Dependent Claim
35 words
A method according to claim 1, wherein the carrier solution is heated to a temperature of 95°-98° C. in the heating step and is cooled to a temperature of 0°-20° C. in the cooling step.
Claim 7
Independent Claim
48 words
The method of any of claims 1 through 5 wherein the following step is effected through the channels in contact via the pores of said membrane selected from the group consisting of polytetrafluoroethylene and acetyl cellulose membranes, said pores having a size of from 1 to 3.5 micrometers.
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) | 1993-10-01 | 1994-04-02 | 1994-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-01 | 1998-04-02 | 1998-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-01 | 2002-04-02 | 2002-10-02 | $7700.00 | Window Closed / Lapsed |