Voltammetric Ion Sensor

• US 20080011606A1
• Filed: 10/14/2005
• Published: 01/17/2008
• Est. Priority Date: 10/15/2004
• Status: Active Grant

• Current Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Harris, Alexander, Bond, Alan, Zhang, Jie
• Granted Patent: US 7,799,204 B2
• Time in Patent Office: Days
• US Class Current: 204/416
• CPC Class Codes: G01N 27/3335 the membrane containing at least one organic component G01N27/3271 takes precedence; aspects concerning the enzyme reagent in enzyme electrodes C12Q1/001
• CPC Class Codes: G01N 27/48 using polarography, i.e. measuring changes in current under a slowly-varying voltage

Abstract

A method for the quantitative determination of an ion in a fluid which comprises subjecting the fluid to voltammetry using a sensing electrode which comprises an electrically conducting support having a surface which is coated with a support matrix, the support matrix containing an electroactive species capable of being oxidised or reduced to form a charged species, and an ionophore.

Claims

1. A method for the quantitative determination of an ion in a fluid which comprises subjecting the fluid to voltammetry using a sensing electrode which comprises an electrically conducting support having a surface which is coated with a support matrix, the support matrix containing an electroactive species capable of being oxidised or reduced to form a charged species, and an ionophore.

2. A method according to claim 1, wherein the support matrix additionally contains a solvent capable of at least partially dissolving the electroactive species and the ionophore.

3. A method according to claim 2, wherein the solvent is a plasticizer.

4. A method according to claim 1, wherein the support matrix additionally contains an ionic salt which is substantially insoluble in the fluid.

5. A method according to claim 4, wherein the ionic salt is selected from tetra (C₄-C₁₆ alkyl) ammonium salts.

6. A method according to claim 5, wherein the ionic salt is selected from tetrabutylammonium tetraphenylborate (TBATPB), tetrahexylammonium tetraphenylborate (THATPB), tetraheptyl ammonium perchlorate (THAClO₄) and tetraheptylammonium borate.

7. A method according to claim 2, wherein the solvent is an ionic liquid.

8. A method according to claim 7, wherein the ionic liquid is selected from 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfonyl)amide (emim.tfsa), N-butyl-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide (P14.tfsa) and trihexyl(tetradecyl)-phosphonium tris(pentafluoroethyl)trifluorophosphate (aph4.cphl2).

9. A method according to claim 1, wherein the electroactive species is hydrophobic.

10. A method according to claim 1, wherein the electroactive species undergoes reversible oxidation/reduction.

11. A method according to claim 1, wherein the electroactive species is selected from decamethylferrocene (DMFc), 1,1′

-dimethylferrocene (DiMFc) and 7,7,8,8-tetracyanoquinodimethane (TCNQ).

12. A method according to claim 1, wherein the sensing electrode has at least one dimension of less than 50 μ

m.

13. A method according to claim 1, wherein the support matrix comprises a dielectric ink.

14. A method according to claim 1, which comprises contacting the fluid with the measuring electrode and with one or more further electrodes, supplying a time varying potential to the sensing electrode and determining the potential at which the resulting current is at a maximum.

15. A method according to claim 1, wherein the fluid is a body fluid selected from blood, urine and saliva.

16. A method according to claim 1, wherein the concentration of the ion in the fluid is from 0.1 μ

mol dm<sup>−

3</sup> to 1.0 mol dm<sup>−

3</sup>, preferably from 0.1 mmol dm<sup>−

3</sup> to 1.0 mol dm<sup>−

3</sup>.

17. A device for the quantitative determination of an ion in a fluid which comprises a sensing electrode as defined in claim 1 and one or more further electrodes.

18. A device according to claim 17, wherein the electrodes are present as conducting tracks on a single base.

19. A device according to claim 17, which comprises two or more sensing electrodes as defined in claim 1.

20. An electrode comprising an electrically conducting support having a surface which is coated with a support matrix, the support matrix containing an electroactive species capable of being oxidised or reduced to form a charged species, and an ionophore.

21. (canceled)