Hybrid film type sensor

• US 7,601,250 B2
• Filed: 11/12/2004
• Issued: 10/13/2009
• Est. Priority Date: 11/19/1999
• Status: Expired due to Fees

• Current Assignee: PerkinElmer LAS, Inc. (Perkinelmer Incorporated)
• Original Assignee: PerkinElmer LAS, Inc. (Perkinelmer Incorporated)
• Inventors: Prohaska, Otto J., Giner, Jose D., LaConti, Anthony B., Manoukian, Mourad
• Primary Examiner(s): Olsen; Kaj K
• Application Number:
  US10/987,825
• Publication Number:
  US 20050126930A1
• Time in Patent Office: 1,796 Days
• Field of Search: 204/412, 204/415, 204/424, 204/431, 204/432
• US Class Current: 204/432
• CPC Class Codes: G01N 27/4045 for gases other than oxygen
• CPC Class Codes: G01N 27/4074 for detection of gases other than oxygen
• CPC Class Codes: G01N 33/004 for CO, CO2

Abstract

A miniaturized gas sensor comprised of thick- or thin-film type electrodes, on a non-conductive supportive substrate, and in contact with a solid ionomer electrolyte, for the detection of toxic gases, i.e., carbon monoxide, and other oxidizable or reducible gases and vapors is described. The all-solid planar sensor cell has two or more film type electrodes arranged on a non-conductive planar surface of a supportive substrate. The electrodes are discrete and in intimate contact with the same solid polymer ionomer membrane. The sensor cell contains no liquid electrolyte and is operated in a constant-voltage, potentiostatic or potentiodynamic mode. A high sensitivity to a select gas or vapor is achieved by a novel three-phase contact area design for a sensing electrode which provides contact with the solid ionomer electrolyte, as well as the gas sample via diffusion openings or holes that penetrate through the supportive substrate.

Claims

1. A sensor cell for detecting gases comprising:

a substrate having a first surface and an opposite second surface;

a sensing electrode;

said sensing electrode in contact with said second surface;

an opening extending from said first surface to said second surface proximate to said sensing electrode for controlling a gas flow; and

a gas diffusion membrane in contact with and extending from said first surface to said sensing electrode, wherein said gas diffusion membrane has a thickness less than said substrate at said opening.

2. The sensor cell of claim 1 whereby said gas diffusion membrane is humidified by an aqueous material.

3. The sensor cell of claim 1 incorporated into a gas sensing instrument.

4. The sensor cell of claim 1, further including a counter electrode.

5. The sensor cell of claim 4 wherein said sensor cell is electronically controlled in a 2 electrode sensor configuration.

6. The sensor cell of claim 4, further including a reference electrode.

7. The sensor cell of claim 6 whereby at least one of said sensing, counter, or reference electrodes contains a fluorocarbon-bonded particulate catalyst which is bonded to an ionomer membrane.

8. The sensor cell of claim 7 whereby said fluorocarbonbonded particulate catalyst is coated with said gas diffusion membrane where said gas diffusion membrane is polymeric.

9. The sensor cell of claim 6 whereby at least one of said sensing, counter, or reference electrodes contains an ionomer-bonded particulate catalyst which is bonded to an ionomer membrane.

10. The sensor cell of claim 9 whereby said ionomer-bonded particulate catalyst is coated with said gas diffusion membrane where said gas diffusion membrane is polymeric.

11. The sensor cell of claim 6 wherein said sensing, counter, and reference electrodes comprise a material selected from the group consisting of Pt, Au, C, platinized Pt, and platinized Au.

12. The sensor cell of claim 6 wherein said sensor cell is electronically controlled in a 3 electrode sensor configuration.

13. The sensor cell of claim 6 wherein said sensor cell is electronically controlled by a potentiostatic circuit connected to said sensing, counter and reference electrodes.

14. The sensor cell of claim 6 wherein said sensor cell is electronically controlled by a potentiodynamic circuit connected to said sensing, counter and reference electrodes.

15. The sensor cell of claim 1 wherein said sensor cell is electronically controlled by a constant voltage source connected to said sensing electrode and an electrochemically reversible counter electrode also acting as a reference electrode.

16. The sensor cell of claim 1 further comprising a microprocessor for real time data readout, data storage and retrieval, and remote data transmission.

17. A sensor cell for detecting gases comprising:

a substrate having a first surface and an opposite second surface;

a sensing electrode;

said sensing electrode in contact with said second surface;

an opening extending from said first surface to said second surface proximate to said sensing electrode for controlling a gas flow; and

a gas diffusion membrane being of polymeric material in contact with and extending from first surface to said sensing electrode, wherein said gas diffusion membrane has a thickness less than said substrate at said opening.

18. The sensor cell in claim 17, wherein said gas diffusion membrane is a non-electrolytic material.

19. The sensor cell of claim 17, wherein said gas diffusion membrane is made of polyethylene.