Multicomponent analysis of volatile organic compositions in vapor samples

• US 20050214169A1
• Filed: 03/25/2005
• Published: 09/29/2005
• Est. Priority Date: 03/26/2004
• Status: Active Grant

• Current Assignee: University of Iowa Research Foundation
• Original Assignee: University of Iowa Research Foundation
• Inventors: Haverhals, Luke M., Leddy, Johna
• Granted Patent: US 8,080,206 B2
• Time in Patent Office: Days
• US Class Current: 422/84
• CPC Class Codes: G01N 27/407 for investigating or analysing gases G01N27/411 takes precedence
• CPC Class Codes: G01N 33/0047 Organic compounds
• CPC Class Codes: G01N 33/497 of gaseous biological material, e.g. breath
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Amounts of volatile organic compositions can be evaluated from vapor samples based on the time dependent response of a fuel cell contacted with the vapor sample at its anode. The time response of the fuel cell signal, e.g., voltage or current, is de-convoluted using a set of standard curves for an equivalent fuel cell configuration obtained separately for each of the volatile organic compositions of a fuel cell with an equivalent construction as the sample-evaluation fuel cell. The methodology can be implemented on a system with an appropriate vapor collection device suitable for the particular application. The method and system can be used to analyze breath samples to evaluate ethanol levels or other volatile organic composition. The system can be a breathalyzer, a vehicle interlock, a medical analysis device or a sensor of environmental or industrial interest.

Claims

1. A method for evaluating amounts of a plurality of volatile organic compositions in a vapor sample, the method comprising fitting a time response curve of a sample-evaluation fuel cell in which the fuel cell anode is contacted with the vapor sample with the analysis based on a function of standard time response curves for an equivalent fuel cell configuration obtained separately for each of the volatile organic compositions on a fuel cell with equivalent construction as sample-evaluation fuel cell.

2. The method of claim 1 wherein the function is a linear combination of the standard time response curves.

3. The method of claim 1 wherein the function is non-linear with respect to the standard time response curves.

4. The method of claim 1 wherein the standard time response curves are normalized to yield a maximum value being one and a minimum value being zero.

5. The method of claim 1 wherein the plurality of volatile organic compositions are ethanol and tobacco smoke.

6. The method of claim 1 wherein the plurality of volatile organic compositions are three compositions.

7. The method of claim 1 wherein fuel cells comprise an ionomer polymer electrolyte/separator.

8. The method of claim 1 wherein the vapor sample is a breath sample.

9. A method for evaluating the intoxication of an individual, the method comprising:

collecting a breath sample; and

evaluating the amount of ethanol as distinguished from at least one other volatile organic composition within the breath sample using the method of claim 1.

10. The method of claim 9 wherein the evaluation is performed with a portable breathalyzer comprising a sample-evaluation fuel cell and a microprocessor.

11. The method of claim 9 wherein the evaluation is performed with a device connected to a vehicle with an ignition interlock that prevents the vehicle from moving is an ethanol level exceeding a selected amount is found.

12. A method for evaluating the medical condition of patient;

the method comprising;

collecting a breath sample; and

evaluating the amounts of selected volatile organic compositions within the breath sample using the method of claim 1 to obtain information related to the health of the patient.

13. A system comprising:

a sample collector;

a flow apparatus that is configured to receive a sample from the sample collector;

a fuel cell comprising an anode connected to the flow system wherein the sample transported within the flow system contacts the anode; and

an analyzer that receives a signal related to a signal from the fuel cell, and evaluates the amounts of a plurality of volatile organic compositions from the time response of the fuel cell signal as a function of time from a de-convolution of the time response of the fuel cell based on separate standard time response functions from each of the volatile organic compositions.

14. The system of claim 13 wherein the sample collector comprises a mouthpiece.

15. The system of claim 13 wherein the flow system comprises a pump that facilitates control of the flow through the flow apparatus.

16. The system of claim 13 wherein the fuel cell comprises an ionomer as the electrolyte.

17. The system of claim 16 wherein the ionomer comprises a perfluoronated, sulfonic acid polymer.

18. The system of claim 13 wherein the anode comprises a porous, conductive carbon cloth gas diffusion layer.

19. The system of claim 13 wherein the analyzer comprises a microprocessor.

20. The system of claim 13 wherein the analyzer performs a linear fit of the standard curves to approximate the sample time response.

21. The system of claim 13 wherein one of the volatile organic compositions is ethanol.

22. The system of claim 13 wherein the system is a portable unit.

23. The system of claim 13 wherein the system further comprises an interface to a vehicle ignition system and wherein the analyzer inhibits ignition of the vehicle engine if a volatile organic composition is measured above a selected value.