Application of electrochemical impedance spectroscopy in sensor systems, devices, and related methods
First Claim
1. A method for real-time detection of sensitivity loss for a working electrode of a sensor, the method comprising:
- periodically performing an electrochemical impedance spectroscopy (EIS) procedure to generate multiple sets of impedance-related data for said working electrode, wherein each of the multiple sets of impedance-related data includes data for at least one impedance-related parameter that is substantially glucose-independent;
for each of said multiple sets of impedance-related data, calculating, by a microprocessor, respective values of 1 kHz imaginary impedance, 0.1 kHz real impedance, and relatively-higher frequency phase angle;
monitoring, by said microprocessor, said respective values over time;
based on said monitoring of the respective values, determining, by said microprocessor, when said respective values of 1 kHz imaginary impedance become more negative over time, that said working electrode is experiencing an oxygen deficiency-led loss of sensitivity;
based on the determination that the working electrode is experiencing an oxygen deficiency-led loss of sensitivity, identifying, by the microprocessor, said working electrode as not behaving normally; and
based on said identification of the working electrode as not behaving normally, alerting a user of the sensor that the sensor should be replaced.
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Abstract
A diagnostic Electrochemical Impedance Spectroscopy (EIS) procedure is applied to measure values of impedance-related parameters for one or more sensing electrodes. The parameters may include real impedance, imaginary impedance, impedance magnitude, and/or phase angle. The measured values of the impedance-related parameters are then used in performing sensor diagnostics, calculating a highly-reliable fused sensor glucose value based on signals from a plurality of redundant sensing electrodes, calibrating sensors, detecting interferents within close proximity of one or more sensing electrodes, and testing surface area characteristics of electroplated electrodes. Advantageously, impedance-related parameters can be defined that are substantially glucose-independent over specific ranges of frequencies. An Application Specific Integrated Circuit (ASIC) enables implementation of the EIS-based diagnostics, fusion algorithms, and other processes based on measurement of EIS-based parameters.
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Citations
4 Claims
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1. A method for real-time detection of sensitivity loss for a working electrode of a sensor, the method comprising:
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periodically performing an electrochemical impedance spectroscopy (EIS) procedure to generate multiple sets of impedance-related data for said working electrode, wherein each of the multiple sets of impedance-related data includes data for at least one impedance-related parameter that is substantially glucose-independent; for each of said multiple sets of impedance-related data, calculating, by a microprocessor, respective values of 1 kHz imaginary impedance, 0.1 kHz real impedance, and relatively-higher frequency phase angle; monitoring, by said microprocessor, said respective values over time; based on said monitoring of the respective values, determining, by said microprocessor, when said respective values of 1 kHz imaginary impedance become more negative over time, that said working electrode is experiencing an oxygen deficiency-led loss of sensitivity; based on the determination that the working electrode is experiencing an oxygen deficiency-led loss of sensitivity, identifying, by the microprocessor, said working electrode as not behaving normally; and based on said identification of the working electrode as not behaving normally, alerting a user of the sensor that the sensor should be replaced. - View Dependent Claims (2, 3, 4)
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Specification