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Electrochemical gas detection method

  • US 3,992,267 A
  • Filed: 04/21/1975
  • Issued: 11/16/1976
  • Est. Priority Date: 10/02/1973
  • Status: Expired
First Claim
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1. The method of quantitatively detecting a gaseous noxious atmospheric pollutant selected from the group consisting of carbon monoxide, nitric oxide, hydrocarbons, ethanol and methanol in air in an electrochemical cell comprising an anode, a cathode, a reference electrode through which no substantial current flows, said anode being selected from the group consisting of platinum, rhodium, iridium, ruthenium, palladium, osmium, tungsten oxide, tungsten carbide, molybdenum oxide, molybdenum sulfide, and alloys or mixtures thereof, and an aqueous electrolyte in contact with said anode, cathode, and reference electrode including the steps of (1) feeding an air sample containing the noxious gas to be detected to the anode of said cell, said sample being substantially free of other noxious gases;

  • (2) maintaining said anode at a fixed potential of from about 0.9 to 1.5 volts with respect to the reversible hydrogen couple in the electrolyte of said cell relative to said reference electrode to oxidize said noxious gaseous substance and simultaneously insure that current due to oxygen reduction or water oxidation within said electrochemical cell is not discernible relative to the level of current produced by said oxidation of gaseous substance; and

    (3) measuring the current flowing between said anode and cathode of said cell to quantitatively determine the amount of said gaseous substance to be detected in said gaseous sample.

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