Electrochemical test strip for reducing the effect of direct interference current

Abstract

This invention describes an electrochemical sensor which is adapted to reduce the effects of interfering compounds in bodily fluids when measuring an analyte in such fluids using an electrochemical strip. The sensor includes a substrate, a first and second working electrodes, and a reference electrode. A reagent layer is disposed on the electrodes such that, in one embodiment it completely covers all of the first working electrode, but only partially covers the second working electrode and, in a second embodiment, it only covers a portion of the first and the second working electrode. The portion of the working electrodes not covered by the reagent layer and is used to correct for the interference effect on the analyte measurement.

Description

PRIORITY [0001] The present invention claims priority to the following U.S. Provisional Applications: U.S. Provisional Application Ser. No. 60 / 516,252 filed on Oct. 31, 2003; U.S. Provisional Application Ser. No. 60 / 558,424 filed on Mar. 31, 2004; and U.S. Provisional Application Ser. No. 60 / 558,728 filed on Mar. 31, 2004. Which applications are hereby incorporated herein by reference. RELATED APPLICATIONS [0002] The present invention is related to the following co-pending U.S. applications: U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5027 USNP], filed on Oct. 29, 2004; U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5042 USNP], filed on Oct. 29, 2004; U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5065], filed on Oct. 29, 2004; U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5066], filed on Oct. 29, 2004; and U.S. patent application Ser. No. ______ [Attorney Docket Number DDI-5067], filed on Oct. 2...

AI Technical Summary

Benefits of technology

[0064] One advantage of the present invention is the ability to use the first and second working electrode to determine that the sample receiving chamber has been sufficiently filled with liquid. It is an advantage of this invention in that the second working electrode not only corrects the interferent effect, but can also measure. glucose. This allows for a more accurate results because 2 glucose measurements can be averaged together while using only one test strip.

is the ability to use the first and second working electrode to determine that the sample receiving chamber has been sufficiently filled with liquid. It is an advantage of this invention in that the second working electrode not only corrects the interferent effect, but can also measure. glucose. This allows for a more accurate results because 2 glucose measurements can be averaged together while using only one test strip.

Problems solved by technology

In particular, desirable oxidation current results from the interaction of the mediator with the analyte of interest (e.g., glucose) while undesirable oxidation current is generally comprised of interfering compounds being oxidized at the electrode surface and by interaction with the mediator.

However, this technique is not always successful since some interfering compounds such as acetaminophen do not have a net negative charge, and thus, can pass through a negatively charged membrane.

Nor would this technique reduce the oxidation current resulting from the interaction of interfering compounds with some mediators.

However, such selective membranes typically make the test strip more complicated to manufacture and increase the test time because the oxidized glucose must diffuse through the selective membrane to get to the electrode.

A disadvantage of this strategy is that mediators having a relatively low potential are often difficult to synthesize, unstable and have a low water solubility.

A disadvantage of this strategy is that it requires that the test strip include an additional electrode and electrical connection (i.e., the dummy electrode) which cannot be used to measure glucose.

The inclusion of dummy electrode is an inefficient use of an electrode in a glucose measuring system.

Images