Open circuit potential amperometry and voltammetry

• US 20050185447A1
• Filed: 04/07/2005
• Published: 08/25/2005
• Est. Priority Date: 03/23/2001
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Lindsey, Jonathan S., Roth, Kristian A., Bocian, David, Kuhr, Werner
• Granted Patent: US 7,826,250 B2
• Time in Patent Office: Days
• US Class Current: 365/151
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G01N 27/3277 being a redox reaction, e.g. detection by cyclic voltammetry voltammetry per se G01N27/42, G01N27/48

Abstract

This invention provides approaches to improve the signal to noise ratio (S/N) in electrochemical measurements (e.g., amperometry, voltammetry, etc.). In particular, a method is described wherein the faradaic current is temporally dissociated from the charging current associated with reading the charge of a redox-active species (e.g., a self-assembled monolayer (SAM)). This method, designated herein as open circuit potential amperometry (OCPA), quantitatively reads the charge of the redox species bound to (electrically coupled to) an electrode surface, while discriminating against both charging current(s) and amperometric signal(s) that arise, e.g., from diffusion-based species in solution.

Claims

1. A device for the detection of an oxidation state of a compound, said device comprising:

a first electrode and a second electrode disposed to contact said compound and thereby form an electrochemical cell;

a voltage source connected to said first electrode;

a switch that allows said compound to be isolated from said voltage source and said electrochemical cell to reach an open circuit potential; and

a current transducer for measuring current produced by said electrochemical cell.

2. The device of claim 1, wherein said device comprises two or more electrochemical cells.

3. The device of claim 2, wherein said device comprises ten or more electrochemical cells.

4. The device of claim 1, wherein said voltage source comprises a voltage follower.

5. The device of claim 1, wherein said current meter comprises a broadband current amplifier.

6. The device of claim 1, wherein said first electrode and said second electrode are disposed in a channel through which a fluid comprising said compound can pass.

7. The device of claim 6, wherein said channel is a capillary tube.

8. The device of claim 6, wherein said is a channel on a chip.

9. The device of claim 1, wherein said electrodes are disposed in a well.

10. The device of claim 1, wherein said electrodes are disposed on a biosensor.

11. The device of claim 1, wherein said electrodes are components of a molecular memory.

12. A molecular memory device comprising:

a first electrode and a second electrode disposed to contact a redox-active compound comprising a porphyrinic macrocycle and thereby form an electrochemical storage cell wherein said first and second electrodes are fixed electrodes;

a voltage source connected to said first electrode;

a switch that allows said compound to be isolated from said voltage source and said storage cell to reach an open circuit potential; and

a current transducer for measuring current produced by said electrochemical cell.

13. The device of claim 12, wherein said device comprises two or more electrochemical cells.

14. The device of claim 13, wherein said device comprises ten or more electrochemical cells.

15. The device of claim 12, wherein said voltage source comprises a voltage follower.

16. The device of claim 12, wherein said current meter comprises a broadband current amplifier.

17. The device of claim 12, wherein said porphyrinic macrocycle is a porphyrin.

18. A molecular memory device comprising:

a first electrode and a second electrode disposed to contact a redox-active compound and thereby form an electrochemical storage cell wherein said first and second electrodes are fixed electrodes;

a write circuit connected to said first electrode;

a switch that allows said compound to be isolated from said write circuit and said storage cell to reach an open circuit potential; and

a sensing circuit sensitive to current produced by said electrochemical cell.

19. The molecular memory of claim 18, wherein said redox-active compound comprises a phorphyrinic macrocycle.