Oxidizable Species as an Internal Reference in Control Solutions for Biosensors
AssigneeBayer HealthCare LLC
InventorsGreg P. Beer, Huan-Ping Wu
Life of this patent
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Abstract
Testing of the performance of an electrochemical meter used to measure the presence of an analyte in a biological sample, particularly glucose in whole blood, includes introducing a control solution containing a predetermined amount of the analyte and a predetermined amount of an internal reference compound. The internal reference compound is selected such that it is oxidized at a potential greater than that used to oxidize the analyte, thereby making it possible to distinguish the control solution from a biological sample.
Claims32
A method of distinguishing a control solution from a sample during operation of an electrochemical sensor measuring the amount of an analyte in said control solution and in said sample, the method comprising the acts of:
- (a) adding to said control solution an internal reference compound, said compound being adapted to be electrochemically oxidized at a potential higher than the potential needed to measure the oxidation of said analyte;
- (b) introducing said control solution containing said internal reference compound and said predetermined amount of said analyte to an electrochemical sensor, said sensor having working and counter electrodes and a reagent;
- (c) at least once applying a potential to said electrochemical sensor sufficient to oxidize said internal reference compound and said analyte, and measuring the resulting electrical current;
- (d) at least once applying a potential to said electrochemical sensor lower than the potential of (c), said potential being sufficient to measure oxidation of said analyte and not sufficient to oxidize said internal reference compounds and measuring the resulting electrical current;
- (e) calculating a Differential Index (DI) defined as DI=ihigh volt/ilow volt
- where:
- ihigh volt is the current measured in (c)
- ilow volt is the current measured in (d)
- (f) determining that a control solution is present when the Differential Index of (e) is sufficiently greater than 1 to distinguish said internal reference compound from said predetermined amount of analyte;
- and
- (g) determining that a sample is present when the Differential Index of (e) is about 1.
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A control solution for use in testing an electrochemical system for measuring the amount of an analyte in a sample, the control solution comprising:
- (a) a predetermined amount of said analyte;
- and
- (b) a predetermined amount of an internal reference compound, said internal reference compound being adapted to be oxidized at a potential higher than the potential required to oxidize said analyte, said predetermined amount of said internal reference compound being proportional to said predetermined amount of analyte such that the presence of said internal reference compound is detectable.
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A method of distinguishing a control solution from a sample during operation of an electrochemical sensor, the electrochemical sensor measuring the amount of an analyte, the method comprising the acts of:
- providing a control solution including an internal reference compound, a buffer and a predetermined amount of analyte, said internal reference compound having a higher potential than the potential needed to measure the oxidation of said analyte, said internal reference compound being different from said buffer;
- providing an electrochemical sensor having a working electrode and a counter electrode;
- introducing said control solution to the electrochemical sensor;
- applying a potential to said electrochemical sensor sufficient to oxidize said internal reference compound and said analyte, and measuring the resulting electrical current;
- applying a lower potential to said electrochemical sensor, said lower potential being sufficient to oxidize said analyte and not sufficient to oxidize said internal reference compound, and measuring the resulting electrical current;
- and
- determining whether a control solution or a sample is present based on the measured electrical currents.
Dependencies are inferred from the claim text.