Amperometric gas sensor

• US 9,459,233 B2
• Filed: 02/26/2013
• Issued: 10/04/2016
• Est. Priority Date: 06/25/2012
• Status: Active Grant

• Current Assignee: Steris Corporation
• Original Assignee: Steris Corporation
• Inventors: Schenk, Elizabeth H., Burke, Peter A., Centanni, Michael A.
• Primary Examiner(s): DIETERLE, JENNIFER M
• Application Number:
  US13/776,953
• Publication Number:
  US 20130341206A1
• Time in Patent Office: 1,316 Days
• Field of Search: 204411-429, 73/233.1, 73/233.2
• US Class Current: 1/1
• CPC Class Codes: A61L 2/202 Ozone
• CPC Class Codes: A61L 2/206 Ethylene oxide
• CPC Class Codes: A61L 2/208 Hydrogen peroxide
• CPC Class Codes: A61L 2/28 Devices for testing the effectiveness or completeness of sterilisation, e.g. indicators which change colour apparatus involving enzymes or microorganisms C12M1/34; methods involving enzymes or microorganisms C12Q1/00
• CPC Class Codes: A61L 2202/14 Means for controlling sterilisation processes, data processing, presentation and storage means, e.g. sensors, controllers, programs
• CPC Class Codes: G01N 27/126 comprising organic polymers
• CPC Class Codes: G01N 27/30 Electrodes, e.g. test electrodes; Half-cells G01N27/414 takes precedence
• CPC Class Codes: G01N 27/301 Reference electrodes
• CPC Class Codes: G01N 27/3335 the membrane containing at least one organic component G01N27/3271 takes precedence; aspects concerning the enzyme reagent in enzyme electrodes C12Q1/001
• CPC Class Codes: G01N 27/4072 characterized by the diffusion barrier
• CPC Class Codes: G01N 27/4074 for detection of gases other than oxygen
• CPC Class Codes: G01N 27/4076 Reference electrodes or reference mixtures
• CPC Class Codes: G01N 33/0036 specially adapted to detect a particular component physical analysis of gaseous biological material G01N33/497

Abstract

The disclosed invention relates to an amperometric gas sensor for measuring the concentration of an analyte, comprising: a solid support; and a working electrode in contact with the solid support; wherein the analyte comprises a dopant which when in contact with the solid support increases the electrical conductivity of the solid support. A sterilization process employing the amperometric gas sensor is disclosed.

Claims

1. An amperometric gas sensor for measuring a concentration of an analyte, the sensor consisting essentially of:

a solid consisting essentially of one or more non-conductive polymers and optionally an electrically non-conductive filler, the solid configured as an insulator without being contacted by the analyte and configured for diffusion of the analyte therethrough, the solid further configured to increase in electrical conductivity when in contact with the analyte;

a working electrode positioned on and in contact with the solid; and

a reference electrode positioned on and in contact with the solid, the reference electrode spaced apart and insulated from the working electrode without the solid being contacted by the analyte, the working electrode and the reference electrode configured to measure electrical conductivity of the solid when the solid is in contact with the analyte.

2. The sensor of claim 1 wherein at least a portion of the solid is amorphous.

3. The sensor of claim 1 wherein at least a portion of the solid is crystalline.

4. The sensor of claim 1 wherein the solid is a porous solid, the volume of voids in the porous solid divided by the total volume of the porous solid being in the range up to about 0.7.

5. The sensor of claim 1 wherein the solid comprises poly (ethylene terephthalate), poly (ethylene oxide), polyvinylidenefluoride, polyethylene, polypropylene, polyethylene-napthlate, polyphenylenesulfide, polycarbonate, polytetrafluoroethylene, polypropylene oxide, acrylic resin, polystyrene, poly(styrene-acrylonitrile), poly(acrylnitrile-butadiene-styrene), polyvinyl chloride, chlorinated polyether, poly(chlorotrifluoro ethylene), or a mixture of two or more thereof.

6. The sensor of claim 1 wherein the solid comprises poly (ethylene terephthalate).

7. The sensor of claim 1 wherein the working electrode comprises a noble metal.

8. The sensor of claim 1 wherein the working electrode comprises gold, platinum, iridium, palladium, osmium, silver, rhodium, ruthenium, titanium, or a mixture of two or more thereof.

9. The sensor of claim 1 wherein the reference electrode comprises a noble metal.

10. The sensor of claim 1 wherein the reference electrode comprises gold, platinum, iridium, palladium, osmium, silver, rhodium, ruthenium, titanium, or a mixture of two or more thereof.

11. The sensor of claim 1 wherein the analyte comprises an oxidizing gas or a reducing gas.

12. The sensor of claim 1 wherein the analyte comprises vaporous hydrogen peroxide, ethylene oxide, ozone, or a mixture of two or more thereof.

13. The sensor of claim 1 wherein the analyte comprises vaporous hydrogen peroxide.

14. The sensor of claim 1 wherein the analyte comprises hydrogen sulfide, hydrogen sulfite, ammonia, methane, ethane, propane, butane, carbon monoxide, oxalic acid, formic acid, ascorbic acid, phosphorous acid, or a mixture of two or more thereof.

15. The sensor of claim 1 wherein the solid comprises poly(ethylene terephthalate), the working electrode comprises palladium, and the analyte comprises vaporous hydrogen peroxide.

16. The sensor of claim 1 wherein the solid is in the form of a poly (ethylene terephthalate) film with a thickness in the range from about 0.05 to about 0.6 mm.

17. The sensor of claim 1 wherein the working electrode and the reference electrode are formed by sputtering palladium on the solid, the solid comprising a poly(ethylene terephthalate) film.

18. The sensor of claim 1 wherein the working electrode and the reference electrode comprise palladium, the thickness of the reference electrode and the working electrode being in the range from about 40 to about 150 nanometers.

19. The sensor of claim 1 wherein the solid comprises a poly (ethylene terephthalate) film, the working electrode and the reference electrode comprising palladium electrodes sputtered on the poly (ethylene terephthalate) film;

the thickness of the electrodes being in the range from about 40 to about 150 nanometers;

the thickness of the poly (ethylene terephthalate) film being in the range from about 0.05 to about 0.6 mm; and

the electrodes being separated from each other by about 0.7 to about 0.9 mm.

20. The sensor of claim 1 wherein the working electrode is connected to a potential control to maintain a stable voltage potential at the working electrode with respect to the reference electrode.

21. The sensor of claim 5 wherein the analyte comprises an oxidizing gas or a reducing gas.

22. The sensor of claim 5 wherein the analyte comprises vaporous hydrogen peroxide, ethylene oxide, ozone, or a mixture of two or more thereof.

23. The sensor of claim 5 wherein the wherein the analyte comprises vaporous hydrogen peroxide.

24. The sensor of claim 5 wherein the analyte comprises hydrogen sulfide, hydrogen sulfite, ammonia, methane, ethane, propane, butane, carbon monoxide, oxalic acid, formic acid, ascorbic acid, phosphorous acid, or a mixture of two or more thereof.

25. The sensor of claim 6 wherein the analyte comprises an oxidizing gas or a reducing gas.

26. The sensor of claim 6 wherein the analyte comprises vaporous hydrogen peroxide, ethylene oxide, ozone, or a mixture of two or more thereof.

27. The sensor of claim 6 wherein the wherein the analyte comprises vaporous hydrogen peroxide.

28. The sensor of claim 6 wherein the analyte comprises hydrogen sulfide, hydrogen sulfite, ammonia, methane, ethane, propane, butane, carbon monoxide, oxalic acid, formic acid, ascorbic acid, phosphorous acid, or a mixture of two or more thereof.