Electrochemical Cell

• US 20100084288A1
• Filed: 09/16/2009
• Published: 04/08/2010
• Est. Priority Date: 06/19/1995
• Status: Active Grant

• Current Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Hodges, Alastair McIndoe, Johansen, Oddvar, Beck, Thomas William
• Granted Patent: US 8,075,760 B2
• Time in Patent Office: Days
• US Class Current: 205/787
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52
• CPC Class Codes: G01N 27/3273 Devices therefor, e.g. test element readers, circuitry details not specific to biochemical electrodes G01N33/4875
• CPC Class Codes: G01N 27/403 Cells and electrode assemblies
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

A method for determining the concentration of a reduced or oxidized form of a redox species is provided. In one exemplary embodiment, an electrochemical apparatus is provided in which the apparatus includes a hollow electrochemical cell for measuring a concentration of glucose in a blood sample, a current of the cell is measured, and a concentration of a redox mediator is determined, at least in part from, a measured current of the cell. The hollow electrochemical cell can include at least one non-metal working electrode, at least one counter electrode or counter/reference electrode, and a spacer interposed between the working electrode and the counter or counter/reference electrode. In one embodiment the working electrode and the counter or counter/reference electrode are not co-planer and are separated by a distance of from about 20 microns to about 200 microns. In another embodiment the working electrode and the counter or counter/reference electrode are not co-planer and the cell has an effective cell volume of less than 1.5 microliters.

Claims

1-30. -30. (canceled)

31. A method for determining the concentration of a reduced or oxidized form of a redox species, said method comprising the steps of:

(1) providing an electrochemical apparatus comprising a hollow electrochemical cell for measuring a concentration of glucose in a blood sample, the hollow electrochemical cell comprising;

a) at least one non-metal working electrode;

b) at least one counter electrode or counter/reference electrode, wherein the working electrode and the counter electrode or counter/reference electrode are not co-planer and are separated by a distance of from about 20 microns to about 200 microns; and

c) a spacer interposed between the working electrode and the counter electrode or counter/reference electrode, wherein the spacer comprises a non-conductive material; and

(2) measuring a current of the cell; and

(3) determining a concentration of a redox mediator from, at least in part, a measured current of the cell.

32. The method of claim 31, wherein the working electrode and the counter electrode or counter/reference electrode are substantially opposed.

33. The method of claim 32, wherein the working electrode and the counter electrode or counter/reference electrode are facing each other.

34. The method of claim 31, wherein the working electrode and the counter electrode or counter/reference electrode are substantially parallel.

35. The method of claim 31, wherein the working electrode and the counter electrode or counter/reference electrode are substantially parallel and substantially opposed.

36. The method of claim 31, wherein the hollow electrochemical cell further comprises a fluid permeable side-wall on at least one side of the hollow cell permitting entry of the sample into the hollow cell.

37. The method of claim 36, wherein the fluid permeable side-wall comprises an opening.

38. The method of claim 31, wherein the hollow electrochemical cell has an effective cell volume of less than 1.5 microliters.

39. The method of claim 31, further comprising applying an electric potential difference between the working electrode and the counter electrode or counter/reference electrode.

40. The method of claim 39, further comprising measuring a current between the working electrode and the counter electrode or counter/reference electrode.

41. The method of claim 31, wherein at least one non-metal working electrode comprises a material selected from the group consisting of graphite, carbon, and carbon-filled plastic.

42. The method of claim 41, wherein at least one counter electrode or counter/reference electrode comprises a metal substrate or a metal coated substrate.

43. The method of claim 42, wherein the metal is selected from the group consisting of gold, silver, platinum, palladium, iridium, lead, and alloys thereof.

44. The method of claim 43, wherein the metal comprises silver, and wherein the blood sample comprises chloride ions and a reduced form of a redox species or an oxidized form of a redox species.

45. The method of claim 31, wherein providing an electrochemical apparatus further comprises a mechanism configured to measure a cell current.

46. The method of claim 31, wherein the non-conductive material of the spacer is a polymeric material.

47. The method of claim 31, wherein walls of the spacer and the electrodes define the effective cell volume of the hollow electrochemical cell.

48. A method for determining the concentration of a reduced or oxidized form of a redox species, said method comprising the steps of:

(1) providing an electrochemical apparatus comprising a hollow electrochemical cell for measuring a concentration of glucose in a blood sample, the hollow electrochemical cell comprising;

a) at least one non-metal working electrode;

b) at least one counter electrode or counter/reference electrode, wherein the working electrode and the counter electrode or counter/reference electrode are not co-planer; and

c) a spacer interposed between the working electrode and the counter electrode or counter/reference electrode, wherein the spacer comprises a non-conductive material, and wherein the hollow electrochemical cell has an effective cell volume of less than 1.5 microliters; and

(2) measuring the current of the cell; and

(3) determining a concentration of a redox mediator from, at least in part, a measured current of the cell.

49. The method of claim 48, wherein the working electrode and the counter electrode or counter/reference electrode are substantially opposed.

50. The method of claim 49, wherein the working electrode and the counter electrode or counter/reference electrode are facing each other.

51. The method of claim 48, wherein the working electrode and the counter electrode or counter/reference electrode are substantially parallel.

52. The method of claim 48, wherein the working electrode and the counter electrode or counter/reference electrode are substantially parallel and substantially opposed.

53. The method of claim 48, wherein the working electrode and the counter electrode or counter/reference electrode are separated by a distance of from about 20 microns to about 200 microns.

54. The method of claim 48, wherein the hollow electrochemical cell further comprises a fluid permeable side-wall on at least one side of the hollow cell permitting entry of the sample into the hollow cell.

55. The method of claim 54, wherein the fluid permeable side-wall comprises an opening.

56. The method of claim 48, further comprising applying an electric potential difference between the working electrode and the counter electrode or counter/reference electrode.

57. The method of claim 56, further comprising measuring a current between the working electrode and the counter electrode or counter/reference electrode.

58. The method of claim 48, wherein at least one non-metal working electrode comprises a material selected from the group consisting of graphite, carbon, and carbon-filled plastic.

59. The method of claim 58, wherein at least one counter electrode or counter/reference electrode comprises a metal substrate or a metal coated substrate.

60. The method of claim 59, wherein the metal is selected from the group consisting of gold, silver, platinum, palladium, iridium, lead, and alloys thereof.

61. The method of claim 60, wherein the metal comprises silver, and wherein the blood sample comprises chloride ions and a reduced form of a redox species or an oxidized form of a redox species.

62. The method of claim 48, wherein providing an electrochemical apparatus further comprises a mechanism configured to measure a cell current.

63. The method of claim 48, wherein the non-conductive material of the spacer is a polymeric material.

64. The method of claim 48, wherein walls of the spacer and the electrodes define the effective cell volume of the hollow electrochemical cell.