Electrochemical cell
First Claim
1. A method for determining the concentration of a reduced or oxidized form of a redox species, said method comprising the steps of:
- (1) disposing a blood sample on an electrochemical apparatus comprising a hollow electrochemical cell for measuring a concentration of glucose in the blood sample, the hollow electrochemical cell comprising;
a) at least one 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 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) applying an electric potential difference between the working electrode and the counter electrode or counter/reference electrode that causes at least one of;
a) a rate of electro-oxidation of a reduced form of a redox species to be determined by a rate of diffusion of the reduced form of the redox species to the working electrode, wherein the working electrode is kept sufficiently anodic when determining a concentration of the reduced form of the redox species; and
b) a rate of electro-reduction of an oxidized form of a redox species to be determined by a rate of diffusion of the oxidized form of the redox species to the working electrode, wherein the working electrode is kept sufficiently cathodic when determining a concentration of the oxidized form of the redox species;
(3) measuring a current between the working electrode and the counter electrode or counter/reference electrode; and
(4) determining the concentration of the reduced or oxidized form of the redox species from at least, the rate of electro-oxidation of the reduced form of the redox species when the working electrode is kept sufficiently anodic or the rate of electro-reduction of the oxidized form of the redox species when the working electrode is kept sufficiently cathodic.
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Accused Products
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.
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Citations
26 Claims
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1. A method for determining the concentration of a reduced or oxidized form of a redox species, said method comprising the steps of:
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(1) disposing a blood sample on an electrochemical apparatus comprising a hollow electrochemical cell for measuring a concentration of glucose in the blood sample, the hollow electrochemical cell comprising; a) at least one 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 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) applying an electric potential difference between the working electrode and the counter electrode or counter/reference electrode that causes at least one of; a) a rate of electro-oxidation of a reduced form of a redox species to be determined by a rate of diffusion of the reduced form of the redox species to the working electrode, wherein the working electrode is kept sufficiently anodic when determining a concentration of the reduced form of the redox species; and b) a rate of electro-reduction of an oxidized form of a redox species to be determined by a rate of diffusion of the oxidized form of the redox species to the working electrode, wherein the working electrode is kept sufficiently cathodic when determining a concentration of the oxidized form of the redox species; (3) measuring a current between the working electrode and the counter electrode or counter/reference electrode; and (4) determining the concentration of the reduced or oxidized form of the redox species from at least, the rate of electro-oxidation of the reduced form of the redox species when the working electrode is kept sufficiently anodic or the rate of electro-reduction of the oxidized form of the redox species when the working electrode is kept sufficiently cathodic. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 24, 25)
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15. A method for determining the concentration of a reduced or oxidized form of a redox species, said method comprising the steps of:
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(1) disposing a blood sample on an electrochemical apparatus comprising a hollow electrochemical cell for measuring a concentration of glucose in the blood sample, the hollow electrochemical cell comprising; a) at least one working electrode; b) at least one counter electrode or counter/reference electrode, wherein the working electrode and the counter electrode or counter/reference electrode; 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) applying an electric potential difference between the working electrode and the counter electrode or counter/reference electrode that causes at least one of; a) a rate of electro-oxidation of a reduced form of a redox species to be determined by a rate of diffusion of the reduced form of the redox species to the working electrode, wherein the working electrode is kept sufficiently anodic when determining a concentration of the reduced form of the redox species; and b) a rate of electro-reduction of an oxidized form of a redox species to be determined by a rate of diffusion of the oxidized form of the redox species to the working electrode, wherein the working electrode is kept sufficiently cathodic when determining a concentration of the oxidized form of the redox species; (3) measuring a current between the working electrode and the counter electrode or counter/reference electrode; and (4) determining the concentration of the reduced or oxidized form of the redox species from at least the rate of electro-oxidation of the reduced form of the redox species when the working electrode is kept sufficiently anodic or the rate of electro-reduction of the oxidized form of the redox species when the working electrode is kept sufficiently cathodic. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 26)
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Specification