Specific and reversible carbon monoxide sensor
AssigneeFCI - FiberChem, Inc.
InventorsKisholoy Goswami, Devinder P. S. Saini, Stanley M. Klainer, Chuka H. Ejiofor
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Abstract
A molybdenum, tungsten or vanadium salt-palladium, ruthenium or osmium salt solution for CO detection is made reversible by addition of ferric, chromium (VI) or cerium (IV) ion. The system is made more CO specific by adding an interference control salt which forms white or colorless precipitates with interfering species. The operational and shelf life are extended by a mixture of counterions; the acetate counterion is particularly useful.
Claims16
A CO sensor comprising, in solution:
- a color forming agent which is reduced by CO and produces a color change;
- a catalyst which is reduced by CO and which thereby also reduces the color forming agent;
- a reversing agent which oxidizes the reduced color forming agent back to its initial oxidation state;
- a redox property modifying agent which prevents reduction of the catalyst and the color forming agent in the absence of CO;
- wherein, the reversing agent is selected from the group consisting of a source of Fe.sup.+3, Cr.sup.+6 and Ce.sup.+4 ions and the redox property modifying agent is a source of acetate counterions.
A CO sensor comprising, in solution:
- a source of Me.sup.+6, W.sup.+6 or V.sup.+5 ions;
- a source of Pd.sup.+2, Ru.sup.+8 or Os.sup.+8 ions and first counterions;
- a source of Fe.sup.+3, Cr.sup.+6 or Ce.sup.+4 ions;
- a source of second counterions to the Pd.sup.+2, Ru.sup.+8 or Os.sup.+8 ions which substantially prevent the Pd.sup..sup.+2, Ru.sup.+8 or Os.sup.+8 ions from being reduced by the first counterions and other counterions in the solution, wherein the second counterions are acetate counterions.
In a CO sensor having a Mo.sub.+6, W.sup.+6 or V.sup.+5 color forming agent, catalyst, and reversing agent in solution, the improvement comprising:
- selecting the catalyst from Ru.sup.+8 or Os.sup.+8 ;
- selecting the reversing agent from Cr.sup.+6 or Ce.sup.+4.
Dependencies are inferred from the claim text.