Thermoelectric sensor for analytes in a gas

• US 20060133960A1
• Filed: 11/14/2005
• Published: 06/22/2006
• Est. Priority Date: 04/28/2003
• Status: Active Grant

• Current Assignee: Invoy Holdings, Inc.
• Original Assignee: Invoy Technologies, LLC
• Inventors: Ahmad, Lubna M.
• Granted Patent: US 8,088,333 B2
• Time in Patent Office: Days
• US Class Current: 422/83
• CPC Class Codes: A61B 5/083 Measuring rate of metabolism by using breath test, e.g. measuring rate of oxygen consumption
• CPC Class Codes: A61B 5/0878 using temperature sensing means
• CPC Class Codes: G01N 33/497 of gaseous biological material, e.g. breath
• CPC Class Codes: G01N 33/4972 Determining alcohol content for vehicle safety devices B60K28/06
• CPC Class Codes: G01N 33/4975 other than oxygen, carbon dioxide or alcohol, e.g. organic vapours

Abstract

An apparatus for sensing at least one analyte in a gas. The apparatus includes a thermoelectric sensor having a layer of at least one analyte interactant that increases or decreases in temperature and at least one thermopile having a first contact pad and a second contact pad, wherein the analyte contacts the interactant and produces or consumes heat, which is transmitted to the thermopile, produces a voltage difference and measures the analyte.

Claims

1. An apparatus for sensing at least one analyte in a gas, the apparatus comprising:

a thermoelectric sensor, the sensor comprising a layer of at least one analyte interactant that increases or decreases in temperature and at least one thermopile, said at least one thermopile having a first contact pad and a second contact pad;

wherein the analyte contacts the interactant and produces or consumes heat, which is transmitted to the thermopile, produces a voltage difference and measures the analyte.

2. The apparatus of claim 1, wherein the interactant is selected from a chemical reactant, catalyst, binding agent, a phase change, adsorbent, absorbent, vaporization agent, aptamer or a combination thereof.

3. The apparatus of claim 1, wherein the sensor further comprises multiple thermopiles, each having the same or different interactants.

4. The apparatus of claim 1, wherein the interactant is selected from sodium hypochlorite, hypochlorous acid, sodium monochloroisocyanurate, monochloroisocynanuric acid, sodium trichloroisocyanurate, trichloroisocyanuric acid, nitrosyl chloride, chloroform, chloroform in the presence of a base, protonating agents or a combination thereof.

5. The apparatus of claim 1 wherein the analyte is acetone, whose presence indicates the presence of ketones in the bloodstream.

6. The apparatus of claim 1, wherein the analyte is alcohol and the interactant is selected from chromium trioxide, alcohol dehydrogenase, alcohol oxidase, acetoalcohol oxidase or a combination thereof.

7. The apparatus of claim 1, wherein the interactants are specific for alkanes, thereby indicating various pathologies, such as breast cancer and transplant rejection.

8. The apparatus of claim 1, wherein the interactant is specific for airborne environmental toxins or classes of toxins, and other airborne components of gas mixtures, thereby detecting these compounds.

9. The apparatus of claim 1, wherein the thermopile comprises metals, alloys, semiconductor materials, or liquid thermoelectric materials.

10. The apparatus of claim 1, wherein the analyte interactant comprises biologically active materials comprising cells, cell organelles, micro-organisms or genetically modified organisms.

11. The apparatus of claim 1, wherein compounds present in the gas other than the analyte of interest facilitate the production or consumption of heat.

12. The apparatus of claim 1, further comprising:

c. a microprocessor in electrical communication with said thermopile, wherein the voltage difference produced by the thermopile is correlated to analyte concentration by said microprocessor, so as to measure the analyte.

13. The apparatus of claim 12, wherein multiple thermopiles, each having the same or different interactants, are each independently connected to said microprocessor via two leads.

14. The apparatus of claim 12, wherein said microprocessor also communicates with an electronic display, noise maker, other output or a combination thereof.

15. The apparatus of claim 1, further comprising:

c. a device for collecting said gas containing the analyte.

16. The apparatus of claim 15, wherein said collecting device is designed to permit the analyte to diffuse from the gas and contact said thermopile.

17. The apparatus of claim 15, wherein said collecting device is designed to permit the analyte to contact said thermopile through direct convection.

18. The apparatus of claim 15, wherein said collecting device is designed to permit the analyte to contact the thermopile through convection across said thermopile, whereby diffusion occurs to bring the analyte in contact with said thermopile.

19. The apparatus of claim 15, wherein said collecting device includes a laminar flow chamber designed to reduce turbulent flow of the gas.

20. The apparatus of claim 15, wherein said collecting device includes a flow restrictor to provide a uniform flow of gas.

21. The apparatus of claim 1, wherein heat is produced or consumed by a mechanism selected from the group consisting of chemical reaction, adsorption, absorption, binding effect, aptamer interaction, physical entrapment, a phase change, or any combination thereof.

22. The apparatus of claim 1, wherein heat is produced or consumed by a biochemical reaction selected from the group consisting of DNA and RNA hybridization, protein interaction and antibody-antigen reactions.

23. The apparatus of claim 1, wherein the interactant is immobilized on or within an inert media.

24. The apparatus of claim 23, wherein the inert media is cellulose acetate.

25. The apparatus of claim 23, wherein the inert media is silicone grease.

26. A method of detecting an analyte in a gas by thermoelectric sensor, the method comprising

a. providing a thermoelectric sensor, the sensor comprising

i. a layer of at least one analyte interactant that when combined with the analyte, gives off or consumes heat;

and

ii. at least one thermopile to which the heat change is transferred, which then registers a voltage difference;

b. contacting the interactant of the thermoelectric sensor with the analyte; and

c. indicating the presence or quantity of the analyte.

27. The method of claim 26, wherein the step of providing the thermoelectric sensor comprises providing an analyte interactant specific for acetone and step c. comprises a display indicating the presence of acetone, whereby lipid metabolism is indicated.

28. The method of claim 26, wherein the provided thermoelectric sensor has multiple thermopiles, each having the same or different analyte interactants, whereby the presence of single or multiple analytes are indicated.

29. The method of claim 26, wherein step c. further comprises indicating the concentration of the analyte.

30. The method of claim 26, wherein the thermoelectric sensor provided in step a. further comprises:

iii. a microprocessor in electrical communication with the thermopile, the microprocessor also communicating with a signal device.

31. The method of claim 26, wherein the provided thermoelectric sensor has multiple thermopiles, each having the same or different analyte interactants and each being connected to the microprocessor by two leads, whereby the presence of single or multiple analytes are indicated.

32. The method of claim 26, further comprising the steps of providing a collection apparatus and collecting the gas containing the analyte.

33. The method of claim 32, further comprising the step of diffusing the analyte from the gas.

34. The method of claim 32, wherein the interactant of the thermosensor is contacted by the analyte through direct convection.

35. The method of claim 32, wherein the collection apparatus includes a laminar flow chamber designed to reduce turbulent flow of the gas.

36. The method of claim 26, wherein heat is produced or consumed by a mechanism selected from the group consisting of chemical reaction, adsorption, absorption, binding effect, aptamer interaction, physical entrapment, a phase change, or any combination thereof.

37. The method of claim 26, wherein heat is produced or consumed by a biochemical reaction selected from the group consisting of DNA and RNA hybridization, protein interaction and antibody-antigen reactions.

38. The method of claim 26, further comprising the step of activating the interactant through the use of an activation agent prior to step b.

39. The method of claim 26, wherein the interactant is trichloroisocyanuric acid, the activation agent is water, producing hypochlorous acid for reaction with acetone.

40. The method of claim 35, wherein the collection apparatus includes a flow restrictor to provide a uniform flow of gas.

41. An apparatus for detecting analytes in fluids comprising:

a) a conduit for channeling said analyte containing fluid past a two or more analyte reaction surfaces in series, said reaction surfaces being coated with an interactant that takes up said analyte and reacts with it to produce a physical reaction that can be sensed;

b) a plurality of sensors disposed to detect said physical reaction; and

c) at least one replenishment region disposed between said at least two analyte reaction surfaces, whereby analyte concentration in said fluid that was depleted by said take up replenished.

42. The apparatus of claim 41, wherein said fluid is a gas.

43. The apparatus of claim 42, wherein said fluid is air.

44. The apparatus of claim 41, wherein said interactant is selected from a group of hydrogenation reactants consisting of Raney nickel and platinum.

45. The apparatus of claim 41, wherein said interactant is selected from a group of adsorbents consisting of activated charcoal and activated carbon impregnated with halogen compounds.

46. The apparatus of claim 41 wherein said sensor is selected from a group of sensor consisting of thermistors, thermocouples, thermopiles, ion sensors, and radiation sensors.

47. The apparatus of claim 41, wherein said replenishment region comprises a portion of conduit having non-reactive walls disposed between said reaction surfaces.

48. The apparatus of claim 47, wherein said replenishment region further has an obstruction disposed therein.

49. The apparatus of claim 41, further comprising at least one temperature compensating reference sensor.

50. The apparatus of claim 49, wherein said conduit has a spacing between top and bottom sensors that is selected to be about two times the maximum thickness of the concentration boundary layer at the end of each reaction region.