System and methods for automatically recognizing a control solution
View Patent ↗Methods and devices for automatically distinguishing between a control solution and an actual patient/user sample in a biosensor are provided. The solution is introduced into an electrochemical cell having a working and counter electrode. Electric pulses are applied to the cell and resultant signals are measured. Based on a comparison of the measured signals, a meter can determine whether the sample is a control solution or an actual patient/user sample.
1. A method for automatically distinguishing between a control solution and an actual patient/user sample in a biosensor comprising:
(a) providing an electrochemical cell comprising:
(i) spaced apart working and counter electrodes; and
(ii) a dry reaction reagent system comprising:
an oxidation-reduction enzyme specific for an analyte;
a first reversible redox species capable of being an electron mediator for the oxidation-reduction enzyme; and
a second reversible redox species, wherein the second redox species has a redox potential different from that of the first redox species;
(b) introducing into the electrochemical cell, a control solution having a known, predetermined concentration of the analyte;
(c) applying at least one electric pulse configured to oxidize or reduce only the first redox species to the electrochemical cell and measuring a first resulting electrical property of the cell;
(d) applying at least one electric pulse configured to oxidize or reduce only the second redox species to the cell and measuring a second resulting electrical property of the cell;
(e) comparing the first and second measurements; and
(f) determining the presence or absence of a control solution based on the results of the comparison performed in part (e).
2. The method of claim 1 , wherein the analyte is glucose.
3. The method of claim 1 , wherein the first and second electrical properties measured are electrochemical signals comprised of electric current signals obtained through multi-step chronoamperometry.
4. The method of claim 1 , wherein the first and second electrical properties measured are electrochemical signals comprised electric current signals obtained through square wave voltammetry.
5. The method of claim 1 , wherein the first and second electrical properties measured are electrochemical signals comprised of electric current signals obtained through differential pulse amperometry.
6. The method of claim 1 , wherein the first and second electrical properties measured are electrochemical signals comprised of electric current signals obtained through cyclic voltammetry.
7. The method of claim 1 , wherein the second reversible redox species is oxidized or reduced at a potential having a magnitude at least 0.2 volts greater or less than that used to oxidize or reduce the first electron mediator.
8. The method of claim 1 , wherein the redox potential of the first reversible redox species is different from the redox potential of the second electron mediator.
9. The method of claim 1 , wherein the second reversible redox species is Ferrocene Dicarboxylic Acid.
10. The method of claim 1 , wherein the second reversible redox species is Ferrocenecarboxylic Acid.
11. The method of claim 1 , wherein the second reversible redox species is gentisic acid (2,5-dihydroxybenzoic acid).
12. The method of claim 1 , wherein the second reversible redox species is 2,3,4-trihydroxybenzoic acid.