Systems and Methods Including Amperometric and Voltammetric Duty Cycles

• US 20100032316A1
• Filed: 07/10/2009
• Published: 02/11/2010
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: WU, Huan-Ping
• Granted Patent: US 8,262,899 B2
• Time in Patent Office: Days
• US Class Current: 205/775
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• 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 27/48 using polarography, i.e. measuring changes in current under a slowly-varying voltage

Abstract

A sensor system including devices and methods for determining the concentration of an analyte in a sample is described. Input signals including amperometric and voltammetric duty cycles of excitations and relaxations may provide a shorter analysis time and/or improve the accuracy and/or precision of the analysis. The disclosed system may reduce analysis errors, thus improving measurement performance, by adjusting the potential and/or scan rate in response to output currents obtained from voltammetric scans. The disclosed system also may determine the concentration of more than one ionizable species in the sample by adjusting the potential and/or scan rate in response to output currents obtained from voltammetric scans. The multiple, determined concentrations may be used to determine the concentration of multiple analytes or to correct the concentration determined for an analyte, thus improving the measurement performance of the system.

Claims

1. A method for measuring an analyte in a sample, comprising:

applying to the sample an input signal comprising a first duty cycle including an amperometric excitation and a first relaxation and a second duty cycle including a voltammetric excitation and a second relaxation;

detecting an output signal, the output signal including output currents responsive to the amperometric excitation and output currents responsive to the voltammetric excitation; and

correlating a portion of the output signal with a concentration of at least one analyte in the sample.

2. The method of claim 1, further comprising adjusting a potential of the amperometric excitation in response to the output currents responsive to the voltammetric excitation.

3. The method of claim 2, comprising correlating the portion of the output signal including at least one output current responsive to the amperometric excitation with the concentration of the at least one analyte in the sample.

4. The method of claim 1, where the input signal further includes a third duty cycle having an acyclic scan and a third relaxation, and

the method further comprises adjusting a potential of the acyclic scan of the third duty cycle in response to the output currents responsive to the voltammetric excitation.

5. The method of claim 4, comprising correlating the portion of the output signal including at least one output current responsive to the acyclic scan of the third duty cycle into the concentration of the at least one analyte in the sample.

6. The method of claim 3 or 5 where adjusting the potential reduces output currents responsive to a second contributing ionizable species in relation to output currents responsive to a first contributing ionizable species in the output signal.

8. The method of claim 6, comprising correlating the portion of the output signal including at least one output current responsive to the first contributing ionizable species with the concentration of the at least one analyte in the sample.

9. The method of claim 1, where the input signal further includes a third duty cycle having an acyclic scan and a third relaxation and the method further comprises,

adjusting at least one of a potential of the amperometric excitation in response to the output currents responsive to the voltammetric excitation and a potential of the acyclic scan in response to the output currents responsive to the voltammetric excitation, where

the adjusting reduces output currents responsive to a second contributing ionizable species in relation to output currents responsive to a first contributing ionizable species in the output signal.

10. The method of claim 9, further comprising comparing the portion of the output signal including at least one output current responsive to the first contributing ionizable species with the portion of the output signal including at least one output current responsive to the second contributing ionizable species to provide a concentration of the second contributing ionizable species.

11. The method of claim 3, or 5, further comprising comparing the portion of the output signal including at least one output current responsive to a first contributing ionizable species with the portion of the output signal including at least one output current responsive to a second contributing ionizable species to provide a concentration of the second contributing ionizable species.

12. The method of claim 6, 9, or 11 where the voltammetric excitation of the second duty cycle is a linear scan.

14. The method of claim 6, 9, or 11 where the voltammetric excitation of the second duty cycle is an acyclic scan having a forward excitation and a reverse excitation.

16. The method of claim 6, 9 or 11 where the second contributing ionizable species is an interferent.

17. The method of claim 1, further comprising adjusting a voltammetric scan rate in response to the output currents responsive to the voltammetric excitation.

7. (canceled)

13. (canceled)

15. (canceled)

18. A measurement device for determining the concentration of an analyte in a sample, comprising:

a signal interface including at least two contacts; and

electrical circuitry establishing electrical communication between the at least two contacts and a signal generator, where the electrical circuitry has a processor in electrical communication with the signal generator and a storage medium,

where the processor is operable to apply an input signal from the signal generator to the at least two contacts, where the input signal includes a first duty cycle having an amperometric excitation and a first relaxation, and where the input signal includes a second duty cycle having a voltammetric excitation and a second relaxation,

where the processor is operable to detect an output signal at the at least two contacts, the output signal including output currents responsive to the amperometric excitation and output currents responsive to the voltammetric excitation, and

where the processor is operable to correlate a portion of the output signal with a concentration of at least one analyte in the sample.

19-31. -31. (canceled)

32. A method for measuring an analyte in a sample, comprising:

applying to the sample an input signal comprising a first duty cycle including a voltammetric excitation and a first relaxation and a second duty cycle including an acyclic scan and a second relaxation;

detecting an output signal, the output signal including output currents responsive to the voltammetric excitation and output currents responsive to the acyclic scan; and

correlating a portion of the output signal with a concentration of at least one analyte in the sample.

33-44. -44. (canceled)

45. A measurement device for determining the concentration of an analyte in a sample, comprising:

a signal interface including at least two contacts; and

electrical circuitry establishing electrical communication between the at least two contacts and a signal generator, where the electrical circuitry has a processor in electrical communication with the signal generator and a storage medium,

where the processor is operable to apply an input signal from the signal generator to the at least two contacts, where the input signal includes a first duty cycle having a voltammetric excitation and a first relaxation, and where the input signal includes a second duty cycle having an acyclic scan and a second relaxation,

where the processor is operable to detect an output signal at the at least two contacts, the output signal including output currents responsive to the voltammetric excitation and output currents responsive to the acyclic scan, and

where the processor is operable to correlate a portion of the output signal with a concentration of at least one analyte in the sample.

46. A method for identifying an ionizable species in a sample, comprising:

applying to the sample an input signal comprising an acyclic scan, the acyclic scan including a forward excitation and a reverse excitation;

detecting an output signal, the output signal including output currents responsive to the acyclic scan;

identifying the ionizable species from the output currents responsive to the forward excitation of the acyclic scan.

47. (canceled)