US5942102A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrochemical method
Assignee: LifeScan Inc
•
Filing: 1997-05-07
•
Granted: 1999-08-24
•
Expires: 2017-05-07
Abstract
Abstract A method for determining the concentration of a reduced or oxidized form of a redox species in an electrochemical cell (FIG. 10) of the kind comprising a working electrode (2) and a counter electrode (16) spaced from the working electrode such that reaction products from the counter electrode arrive at the working electrode, the method comprising the steps (FIG. 5) of applying (21) an electric potential between the electrodes, such that the electro-oxidation of the redox species is diffusion controlled, determining the current as a function of time, estimating the magnitude of the steady state current (23), reversing the potential, again determining current as a function of time and estimating the reverse potential steady state (25).
Inventors
- 👤 Alastair McIndoe Hodges
- 👤 Thomas William Beck
- 👤 Oddvar Johansen
- 👤 Ian Andrew Maxwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:47
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; C; C12; C12Q; C12Q1/00; C12Q1/001; C12Q1/005; C12Q1/006; C12Q1/004; G01N27/28; G01N27/30; G01N27/327; G01N27/3271; G01N27/3272
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
169 words
A method for determining the concentration of a reduced or oxidized2 form of a redox species in an electrochemical cell of the kind comprising a working electrode and a counter electrode spaced from the working electrode by a predetermined distance, said method comprising the steps of: (a) applying an electric potential between the electrodes, wherein the electrodes are spaced so that reaction products from the counter electrode arrive at the working electrode by diffusion and wherein the potential of the working electrode is such that the rate of the electro-oxidation of the reduced form or electroreduction of the oxidised form of the redox species is diffusion controlled, (b) determining current as a function of time after application of the potential and prior to achievement of a steady state, (c) estimating the magnitude of the steady state current, (d) interrupting and reapplying, or reversing the polarity, of the potential, (e) repeating step (b) and step (c) to estimate the concentration of the reduced or oxidized form of the redox species.
Claim 2
Independent Claim
169 words
A method for determining the concentration of a reduced or oxidized2 form of a redox species in an electrochemical cell of the kind comprising a working electrode and a counter electrode spaced from the working electrode by a predetermined distance, said method comprising the steps of: (a) applying an electric potential between the electrodes, wherein the electrodes are spaced so that reaction products from the counter electrode arrive at the working electrode by diffusion and wherein the potential of the working electrode is such that the rate of the electro-oxidation of the reduced form or electroreduction of the oxidised form of the redox species is diffusion controlled, (b) determining current as a function of time after application of the potential and prior to achievement of a steady state, (c) estimating the magnitude of the steady state current, (d) interrupting and reapplying, or reversing the polarity, of the potential, (e) repeating step (b) and step (c) to estimate the concentration of the reduced or oxidized form of the redox species.
Claim 3
Dependent Claim
14 words
A method according to claim 1 wherein the polarity is reversed in step (d).
Claim 4
Dependent Claim
19 words
A method according to claim 1 or claim 2 wherein the electrodes are separated by less than 500 microns.
Claim 5
Dependent Claim
19 words
A method according to claim 1 or claim 2 wherein the electrodes are separated by less than 200 microns.
Claim 6
Independent Claim
30 words
A method according to any one of the preceding claims wherein the working electrode extends in a plane parallel to and facing the plane in which the counter electrode extends.
Claim 7
Dependent Claim
53 words
A method according to claim 1 or claim 2 wherein a sample is allowed to react with an enzyme catalyst and a redox mediator said method comprising the prior step of operating the cell at a potential higher than that of the redox reaction so as to oxidize hydrogen peroxide at the anode.
Claim 8
Dependent Claim
31 words
A method according to claim 1 wherein the potential is reversed repetitively and the concentration of the species is estimated as an average from the result obtained prior to each reversal.
Claim 9
Dependent Claim
16 words
A method according to claim 1 wherein the cell contains an enzyme and a redox mediator.
Claim 10
Dependent Claim
12 words
A method according to claim 8 wherein the cell contains glucose oxidase.
Claim 11
Dependent Claim
11 words
A method according to claim 8 wherein the cell contains ferricyanide.
Claim 12
Dependent Claim
152 words
A method according to claim 1 wherein a sample is admitted to the cell and allowed to react to produce an electrochemically oxidizable or reducible species further comprising the steps of: (a) applying a potential between the electrodes before or during filling of the cell, (b) measuring the change in current as a function of time, (c) determining or predicting from the measurement in step (b) the time of substantial completion of said reaction and/or the magnitude of the measured current upon substantial completion of said reaction, (d) then interrupting and reapplying, or reversing the polarity of, the potential, (e) then determining current as a function of time after reapplication or reversal of the potential and prior to achievement of a steady state, (f) estimating the magnitude of the steady state current, and (g) from the results of steps (c), (e) and (f) estimating the concentration of an analyte in the sample.
Claim 13
Dependent Claim
31 words
A method according to claim 11 further comprising a second cell containing a known concentration of analyte or reduced mediator and wherein the second cell is used to calibrate the first.
Claim 14
Dependent Claim
24 words
A method according to claim 11 wherein a known concentration of analyte or reduced mediator is added to the analyte and used for calibration.
Claim 15
Dependent Claim
21 words
A method according to claim 11 wherein the potential is applied between the electrodes continuously between step (a) and step (c).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-08-23 | 2003-02-22 | 2003-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-23 | 2007-02-22 | 2007-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-08-23 | 2011-02-22 | 2011-08-24 | $7700.00 | Window Closed / Lapsed |