Abstract A method and apparatus for determing the oxygen demand of aqueous samples, the arrangement including cell means for receiving an aqueous sample during determination, the cell including an anode disposed within an anode compartment and a cathode disposed remote from the anode compartment. Bridging means are provided for electrolytically coupling the electrodes in the cell, the briding means normally including an ion permeable membrane which extends continuously between the anode and cathode to physically isolate and electrically couple the electrodes. Temperature control means are provided for maintaining the cell at a constant temperature level, and electrical power means are coupled to the electrodes for delivering a predetermined integral quantity of electrolyzing current across the electrodes at a potential level sufficient for generating oxygen along the anode surface, the quantity of electrolyzing current normally being in excess of the quantity needed to render the solution substantially electro-inactive, this condition being reached, for example, upon the oxidation of at least a substantial portion of the organic waste products present in the sample. Means are provided for determining the quantity or rate of oxygen evolution as a result of the delivery of the integral quantity of electrolyzing current to the cell. The method may further incorporate an alkali metal hydoxide in the sample undergoing determination in order to achieve a pH in excess of about 10, the alkali metal hydroxide being utilized to absorb any carbon dioxide which may be generated as a result of oxidation of organic waste products.
Inventors
👤 J Cummings
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-28 17:26
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/18; G01N33/1806
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
159 words
THE METHOD OF QUANTITATIVELY DETERMINING THE OXYGEN DEMAND OF AQUEOUS SAMPLES COMPRISING; A. PLACING AN AQUEOUS SAMPLE FOR OXYGEN DEMAND DETERMINATION INTO AN ELECTROLYTIC CELL HAVING A PAIR OF ELECTRODES IN CONTACT WITH SAID SAMPLE AND INCLUDING AN ANODE DIS POSED WITHIN AN ANODE COMPARTMENT, A CATHODE DISPOSED REMOTE FROM SAID ANODE COMPARTMENT AND AN ION PERMEABLE MEMBRANE IN CONTACT WITH SAID SAMPLE TO PROVIDE AN ELECTROLYTIC BRIDGE BETWEEN SAID ANODE AND SAID CATHODE; B. ADDING AN ALKALI METAL HYDROXIDE TO SAID SAMPLE UNTIL THE PH OF SAID SAMPLE IS IN EXCESS OF ABOUT 10; C. APPLYING AN ELECTROLYZING CURRENT ACROSS SAID ELECTRODES AT A POTENTIAL SUITABLE FOR THE GENERATION OF OXYGEN ALONG THE SAMPLE CONTACTING SURFACE OF THE ANOFDDE UNTIL THE SAMPLE IS SUBSTANTIALLY ELECTRO-INACTIVE WHILE MAINTAINING SAID SAMPLE AT A SUBSTANTIALLY CONSTANT TEMPERATURE; AND D. MEASURING THE PARTIAL PRESSURE OF OXYGEN EVOLVED FROM SAID ANODE-SAMPLE INTERFACE DURING SAID ELECTROLYZING CURRENT APPLICATION WHEN SAID SAMPLE IS SUBSTANTIALLY ELECTRO-INACTIVE.
Claim 2
Independent Claim
159 words
THE METHOD OF QUANTITATIVELY DETERMINING THE OXYGEN DEMAND OF AQUEOUS SAMPLES COMPRISING; A. PLACING AN AQUEOUS SAMPLE FOR OXYGEN DEMAND DETERMINATION INTO AN ELECTROLYTIC CELL HAVING A PAIR OF ELECTRODES IN CONTACT WITH SAID SAMPLE AND INCLUDING AN ANODE DIS POSED WITHIN AN ANODE COMPARTMENT, A CATHODE DISPOSED REMOTE FROM SAID ANODE COMPARTMENT AND AN ION PERMEABLE MEMBRANE IN CONTACT WITH SAID SAMPLE TO PROVIDE AN ELECTROLYTIC BRIDGE BETWEEN SAID ANODE AND SAID CATHODE; B. ADDING AN ALKALI METAL HYDROXIDE TO SAID SAMPLE UNTIL THE PH OF SAID SAMPLE IS IN EXCESS OF ABOUT 10; C. APPLYING AN ELECTROLYZING CURRENT ACROSS SAID ELECTRODES AT A POTENTIAL SUITABLE FOR THE GENERATION OF OXYGEN ALONG THE SAMPLE CONTACTING SURFACE OF THE ANOFDDE UNTIL THE SAMPLE IS SUBSTANTIALLY ELECTRO-INACTIVE WHILE MAINTAINING SAID SAMPLE AT A SUBSTANTIALLY CONSTANT TEMPERATURE; AND D. MEASURING THE PARTIAL PRESSURE OF OXYGEN EVOLVED FROM SAID ANODE-SAMPLE INTERFACE DURING SAID ELECTROLYZING CURRENT APPLICATION WHEN SAID SAMPLE IS SUBSTANTIALLY ELECTRO-INACTIVE.
Claim 3
Dependent Claim
19 words
The method as defined in claim 1 being particularly characterized in that said alkali metal hydroxide is potassium hydroxide.
Claim 4
Dependent Claim
26 words
The method as defined in claim 1 being particularly characterized in that said sample is treated with potassium hydroxide until the solution concentration is substantially 1N.
Claim 5
Dependent Claim
24 words
The method as defined in claim 1 being particularly characterized in that said aqueous sample is maintained at a temperature of about 30* C.
Claim 6
Dependent Claim
24 words
The method as defined in claim 1 being particularly characterized in that said electrolyzing current flows through said cell at a substantially constant rate.
Claim 7
Dependent Claim
21 words
The method as defined in claim 5 being particularly characterized in that said electrolyzing current is maintained at substantially 500 ma.