Electrochemical sensors

• US 8,506,779 B2
• Filed: 09/22/2011
• Issued: 08/13/2013
• Est. Priority Date: 06/07/2007
• Status: Expired due to Fees

• Current Assignee: Sensor Innovations, Inc.
• Original Assignee: Sensor Innovations, Inc.
• Inventors: Kahn, Carolyn R., Wong, Elicia, Norviel, Vern
• Primary Examiner(s): Ball, J. Christopher
• Assistant Examiner(s): DIETERLE, JENNIFER M
• Application Number:
  US13/241,171
• Publication Number:
  US 20120067724A1
• Time in Patent Office: 691 Days
• Field of Search: 204400-436, 205775-792, 548/406
• US Class Current: 204/416
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: C09K 2323/023 Organic silicon compound, e.g. organosilicon
• CPC Class Codes: C12M 41/32 of substances in solution
• CPC Class Codes: G01N 27/407 for investigating or analysing gases G01N27/411 takes precedence
• CPC Class Codes: G01N 27/4167 pH electrodes therefor G01N27/302, G01N27/36
• CPC Class Codes: Y10T 428/24421 Silicon containing
• CPC Class Codes: Y10T 428/2995 Silane, siloxane or silicone coating

Abstract

Described herein are substrates, sensors and systems related to measuring the concentration of an analyte such as hydrogen ion in a sample. Redox active moieties whose reduction and/or oxidation potentials are sensitive to the presence of an analyte are immobilized onto a surface of an electrode. Immobilized redox active moieties whose reduction and/or oxidation potential are insensitive to the analyte can be used for reference. Voltammetric measurements made using such modified surfaces can accurately determine the presence and/or concentrations of analytes in a sample of interest. The electrochemical sensors of the invention are robust and can be made so as not to require calibration or recalibration.

Claims

1. A pH sensor, comprising:

a non-metallic solid state electrode having a surface having immobilized thereon a redox-active moiety, wherein the redox-active moiety exhibits an oxidation potential and/or a reduction potential that is sensitive to the presence of hydrogen ion,

wherein the redox-active moiety is immobilized on the surface of the solid state electrode through a carbon covalent bond, and

wherein said pH sensor has a sensitivity of at least about 45.1 mV per pH unit.

2. The pH sensor of claim 1, further comprising an additional redox-active moiety having an oxidation potential and/or reduction potential that is insensitive to the presence of hydrogen ion, wherein said additional redox-active moiety is immobilized on i) said surface or ii) a surface of an additional electrode.

3. The pH sensor of claim 1, wherein said non-metallic solid state electrode is formed of silicon.

4. The pH sensor of claim 1, wherein the pH sensor has an accuracy to within about 0.5 pH units or less.

5. The pH sensor of claim 1, wherein the non-metallic solid state electrode is chemically doped.

6. The pH sensor of claim 5, wherein the non-metallic solid state electrode is chemically doped p-type.

7. A pH sensor, comprising:

a first non-metallic working electrode having a surface having immobilized thereon a first redox-active moiety, wherein the first redox-active moiety exhibits an oxidation potential and/or a reduction potential that is sensitive to the presence of hydrogen ion; and

a second non-metallic working electrode electrically isolated from said first working electrode, said second working electrode having a surface having immobilized thereon a second redox-active moiety, wherein the second redox-active moiety exhibits an oxidation potential and/or a reduction potential that is insensitive to the presence of hydrogen ion,

wherein said pH sensor has an accuracy to within about 1 pH unit or less while in use or storage for about ten hours or more.

8. The pH sensor of claim 7, wherein said pH sensor has an accuracy to within about 0.5 pH units or less.

9. The pH sensor of claim 7, wherein said pH sensor has an accuracy to within about 0.02 pH units or less.

10. The pH sensor of claim 7, wherein said first non-metallic working electrode is formed of silicon.

11. The pH sensor of claim 7, wherein the pH sensor has a sensitivity of at least about 45.1 mV per pH unit.

12. The pH sensor of claim 7, wherein the pH sensor is accurate at measuring the concentration of hydrogen ion to about 10% or less while in use or storage for about ten hours or more.

13. The pH sensor of claim 7, wherein the pH sensor is accurate at measuring the concentration of hydrogen ion to about 1% or less while in use or storage for about ten hours or more.

14. The pH sensor of claim 7, wherein the first redox-active moiety is immobilized on the surface of the first non-metallic working electrode by a carbon covalent bond between said redox-active moiety and said surface.

15. A calibration-free sensor, comprising:

a non-metallic electrode having a surface having immobilized thereon a redox-active moiety exhibiting an oxidation potential and/or a reduction potential that is sensitive to the presence of hydrogen ion; and

a microprocessor programmed to measure the concentration of said hydrogen ion at an accuracy within about 50% or less while in use or storage for about ten hours or more without calibration.

16. The calibration-free sensor of claim 15, further comprising an additional redox-active moiety having an oxidation potential and/or reduction potential that is insensitive to the presence of said hydrogen ion, wherein said additional redox-active moiety is immobilized on i) said surface or ii) a surface of an additional electrode.

17. The calibration-free sensor of claim 15, wherein the sensor is accurate at measuring the concentration of said hydrogen ion to about 10% or less when in use or storage for about ten hours or more.

18. The calibration-free sensor of claim 15, wherein the sensor is accurate at measuring the concentration of said hydrogen ion to about 2% or less when in use or storage for about ten hours or more.

19. The calibration-free sensor of claim 15, wherein the sensor is accurate at measuring the concentration of said hydrogen ion to about 1% or less when in use or storage for about ten hours or more.

20. The calibration-free sensor of claim 15, wherein said non-metallic electrode is formed of silicon.

21. The calibration-free sensor of claim 15, wherein the sensor has a sensitivity of at least about 45.1 mV per pH unit.

22. The calibration-free sensor of claim 15, wherein the redox-active moiety is immobilized on the surface by a carbon covalent bond between said redox-active moiety and said surface.

23. A system, comprising:

a sensor comprising a non-metallic solid state electrode having a surface having immobilized thereon a redox-active moiety exhibiting an oxidation potential and/or a reduction potential that is sensitive to the presence of an hydrogen ion; and

a power supply that provides power to said sensor to sense said hydrogen ion, said power supply comprising a battery,

wherein the sensor is disposable or single-use.

24. The system of claim 23, further comprising an additional redox-active moiety having an oxidation potential and/or reduction potential that is insensitive to the presence of said hydrogen ion, wherein said additional redox-active moiety is immobilized on i) said surface or ii) a surface of an additional electrode that is electrically isolated from said solid state electrode.

25. The system of claim 23, wherein said non-metallic solid state electrode is formed of silicon.

26. The system of claim 23, wherein said power supply is a disposable, chemically-based battery.

27. The system of claim 23, wherein said power supply is an encapsulated module removable from said disposable or single-use sensor.

28. The system of claim 23, wherein the redox-active moiety is immobilized on the surface by a carbon covalent bond between said redox-active moiety and said surface.

29. The system of claim 23, wherein said non-metallic solid state electrode is substantially planar.

30. The system of claim 23, wherein the sensor is accurate at measuring the concentration of said hydrogen ion to about 1% or less when in use or storage for about ten hours or more.