Electrochemical-sensor design
First Claim
1. An electrochemical sensor for detecting the concentration of analyte in a fluid test sample which comprises:
- 1) a base which provides a flow path for the fluid test sample having on its surface a counter electrode and a working electrode in electrical communication with a detector of electrical current;
2) a reaction layer on the surface of at least the working electrode comprising an enzyme which reacts with the analyte to produce electrons that are transferred to the working electrode; and
3) a cover which when mated with the base member forms a capillary space with an opening for the introduction of fluid test sample thereto which space contains the flow path for the fluid test sample in which the counter and working electrodes are situated so that the major portion of the counter electrode is located downstream of the opening from the working electrode with a sub-element of the counter electrode being upstream of the working electrode so that when electrical communication between only the sub-element and working electrode takes place there is insufficient flow of electrical current through the detector to constitute a valid test for the concentration of analyte in the fluid test sample and the detector is pre-programmed to emit an error signal in the event of such insufficient flow of electrical current.
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Accused Products
Abstract
Disclosed is an improved electrochemical sensor having a base bearing a working and counter electrode which provides a flow path for a fluid test sample. The working electrode has a reaction layer on its surface which contains an enzyme capable of reacting with an analyte to produce electrons which are received by the working electrode. The base is mated with a cover to form a capillary space into which the test fluid is drawn. The improvement involves configuring the working and counter electrodes so that a major portion of the counter electrode is located downstream on the flow path from the working electrode with the exception of a small sub-element of the counter electrode which is in electrical communication with the primary portion of the counter electrode and located upstream of the working electrode. This configuration provides the sensor with the capability of sending a greatly reduced electrical signal to the device'"'"'s detecting element in the event that the capillary space is incompletely filled with test fluid. This reduced signal can be manipulated to produce an error signal which affirmatively apprises the device'"'"'s user that such incomplete filling has occurred.
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Citations
15 Claims
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1. An electrochemical sensor for detecting the concentration of analyte in a fluid test sample which comprises:
- 1) a base which provides a flow path for the fluid test sample having on its surface a counter electrode and a working electrode in electrical communication with a detector of electrical current;
2) a reaction layer on the surface of at least the working electrode comprising an enzyme which reacts with the analyte to produce electrons that are transferred to the working electrode; and
3) a cover which when mated with the base member forms a capillary space with an opening for the introduction of fluid test sample thereto which space contains the flow path for the fluid test sample in which the counter and working electrodes are situated so that the major portion of the counter electrode is located downstream of the opening from the working electrode with a sub-element of the counter electrode being upstream of the working electrode so that when electrical communication between only the sub-element and working electrode takes place there is insufficient flow of electrical current through the detector to constitute a valid test for the concentration of analyte in the fluid test sample and the detector is pre-programmed to emit an error signal in the event of such insufficient flow of electrical current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- 1) a base which provides a flow path for the fluid test sample having on its surface a counter electrode and a working electrode in electrical communication with a detector of electrical current;
Specification