Electrochemical detection of hydrogen cyanide

• US 6,001,240 A
• Filed: 07/02/1997
• Issued: 12/14/1999
• Est. Priority Date: 07/02/1997
• Status: Expired due to Term

• Current Assignee: Mine Safety Appliances Company (MSA Safety, Inc.)
• Original Assignee: Mine Safety Appliances Company (MSA Safety, Inc.)
• Inventors: Dorisio Deininger, Debra J., Scheffler, Towner B.
• Primary Examiner(s): TUNG, TA HSUNG
• Application Number:
  US08/887,025
• Time in Patent Office: 895 Days
• Field of Search: 205/780.5, 205/782.5, 205/783, 204/415, 204/412, 204/431, 204/432
• US Class Current: 205/780.5
• CPC Class Codes: G01N 27/4045 for gases other than oxygen

Abstract

The present invention provides an electrochemical sensor for the detection of hydrogen cyanide. In general, the electrochemical sensor includes a housing having disposed therein a working electrode, a reference electrode and a counter electrode. The electrochemically active surfaces of the working electrode and reference electrode preferably comprise silver. Electrical connection is maintained between the working electrode and the counter electrode via an organic electrolyte present within the housing. The electrochemical gas sensor preferably further comprises circuitry for maintaining the working electrode at a potential in the range of approximately +40 mV to approximately -40 mV versus the silver reference electrode. Most preferably, the electrochemical gas sensor comprises circuitry for maintaining the working electrode at a potential of approximately 0 mV versus the silver reference electrode. The present invention also provides a method of using such a sensor to detect hydrogen cyanide.

Claims

1. A method of using an electrochemical gas sensor for the detection of hydrogen cyanide, the electrochemical gas sensor comprising a working electrode, a reference electrode and a counter electrode, the electrochemically active surface of the working electrode comprising silver, the electrochemically active surface of the reference electrode comprising sintered silver metal powder, the method comprising the steps of:

a. maintaining electrical connection between the working electrode and the counter electrode with an organic electrolyte;

b. placing the electrochemical gas sensor in communicative connection with an environment containing hydrogen cyanide such that hydrogen cyanide can react at the working electrode; and

c. measuring t he cur rent flow between the working electrode and the counter electrode to obtain a measurement of the concentration of hydrogen cyanide in the environment.

2. The method of claim 1 further comprising the step of:

d. maintaining the working electrode at a potential in the range of approximately +40 mV to approximately -40 mV versus the silver reference electrode.

3. The method of claim 2 wherein the working electrode is maintained at a potential in the range of approximately +20 mV to approximately -20 mV versus the silver reference electrode.

4. The method of claim 3 wherein the working electrode is maintained at a potential of approximately 0 mV versus the silver reference electrode.

5. The method of claim 4 wherein the counter electrode comprises silver.

6. The method of claim 4 wherein the counter electrode comprises sintered silver metal powder.

7. The method of claim 4 wherein the working electrode comprises sintered silver metal powder.

8. The method of claim 4 wherein both the working electrode and the counter electrode comprise sintered silver metal powder.

9. The method of claim 3 wherein the counter electrode comprises silver.

10. The method of claim 3 wherein the counter electrode comprises sintered silver metal powder.

11. The method of claim 3 wherein the working electrode comprises sintered silver metal powder.

12. The method of claim 3 wherein both the working electrode and the counter electrode comprise sintered silver metal powder.

13. The method of claim 2 wherein the counter electrode comprises silver.

14. The method of claim 2 wherein the working electrode comprises sintered silver metal powder.

15. The method of claim 2 wherein the counter electrode comprises sintered silver metal powder.

16. The method of claim 2 wherein both the working electrode and the counter electrode comprise sintered silver metal powder.

17. The method of claim 1 wherein the electrochemically active surface of the counter electrode comprises elemental silver.

18. The method of claim 17 wherein the counter electrode comprises sintered silver metal powder.

19. The method of claim 1 wherein the working electrode comprises sintered silver metal powder.

20. The method of claim 1 wherein both the working electrode and the counter electrode comprise sintered silver metal powder.