Measuring device and methods for use therewith
Inventors
Harding, Ian • Iyengar, Sridhar G. • Wei, Baoguo • Diamond, Steven • Vu, Sonny • Forest, Martin • Huang, Eileen • Flaherty, Joseph
Assignees
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Publication Number
US-7964146-B2
Publication Date
2011-06-21
Expiration Date
Abstract
The ability to switch at will between amperometric measurements and potentiometric measurements provides great flexibility in performing analyses of unknowns. Apparatus and methods can provide such switching to collect data from an electrochemical cell. The cell may contain a reagent disposed to measure glucose in human blood.
Core Innovation
The invention relates to an electrochemical measurement device that performs both amperometric measurement and potentiometric measurement for an electrochemical cell. Under automatic control, a source of potential external to the electrochemical cell controllably applies a potential so that a current flows through the electrochemical cell in the presence of an analyte, and a corresponding current measurement is used to evaluate a measure of the analyte in a bodily fluid.
Thereafter, the electronic control means ceases the application of the applied potential to the electrochemical cell. After cessation, the potentiometric circuitry measures a decay in chemical potential at the electrochemical cell in the absence of the applied potential, and the invention evaluates the measured current together with the measured decay in chemical potential to evaluate the analyte.
In the disclosed handheld test equipment implementations, potentiometric circuitry and amperometric means are arranged so that current is measured during application of the potential and chemical potential decay is measured after the applied potential is ceased. The approach uses automatic control to switch between the measurement phases and is contrasted with prior art requiring manual mode selection.
The document further describes implementation concepts including switch-controlled electrode isolation for taking potentiometric readings and circuit blocks for electronic control that enable the automatic switching. The described measurement approach uses time-variant potentials and generation of chemical potential gradients by applied potential/current, followed by monitoring of chemical potential relaxation/decay to correct analyte-dependent signals.
Claims Coverage
The independent claims are clm-00001, clm-00028, clm-00057, and clm-00085, each centered on automatic control that applies a potential, measures current, then ceases the applied potential and measures decay in chemical potential using potentiometric circuitry.
Applying a potential and measuring current under automatic control
Under automatic control of the electronic circuitry, applying a potential to the electrochemical cell by means of a source of potential external to the cell and measuring said current indicative of the presence of analyte.
Ceasing the applied potential and measuring decay in chemical potential
Thereafter, under automatic control of the electronic circuitry, ceasing the application of the potential to the cell; thereafter, under automatic control of the electronic circuitry, measuring a decay in chemical potential at the cell.
Evaluating current and chemical potential decay to evaluate analyte
Evaluating the measured current and the measured decay of chemical potential to evaluate a measure of the analyte in the bodily fluid.
Handheld test equipment with external potentiometric circuitry and automatic cessation
A handheld test equipment comprising an electrochemical cell comprising at least first and second electrodes and a reagent reactive with a constituent of a human bodily fluid; a source of potential external to the electrochemical cell; potentiometric circuitry external to the electrochemical cell; electronic control means coupled with the source of potential to controllably apply the source of potential to the electrochemical cell, thereby allowing current to flow through the cell; amperometric means external to the electrochemical cell for measuring the flow of current through the electrochemical cell; wherein the electronic control means is coupled with the potentiometric circuitry to automatically cease application of potential to the electrochemical cell, and then cause the potentiometric circuitry to measure a decay in chemical potential at the electrochemical cell in the absence of the applied potential.
Housing and connector implementation with automated cessation and decay measurement
A housing; a connector at the housing having at least first and second contacts; a source of potential; potentiometric circuitry within the housing; electronic control means within the housing; the electronic control means coupled with the current source or source of potential to controllably apply the source of potential to the at least first and second contacts; amperometric means within the housing for measuring the current flowing through the at least first and second contacts; wherein the electronic control means is coupled with the potentiometric circuitry to automatically cease application of the potential to the at least first and second contacts, and then cause the potentiometric circuitry to measure a decay of chemical potential at the at least first and second contacts in the absence of the applied current or potential.
Test equipment with external potentiometric and amperometric measurement and chemical potential decay
A test equipment comprising an electrochemical cell comprising first and second electrodes and a reagent reactive with a constituent of a human bodily fluid; a source of potential external to the electrochemical cell; potentiometric circuitry external to the electrochemical cell; electronic control means; the electronic control means coupled with the source of potential to controllably apply the potential to the electrochemical cell, thereby allowing current to flow through the cell in the presence of an analyte of interest; amperometric means external to the electrochemical cell for measuring the current passed through the electrochemical cell; wherein the electronic control means is coupled with the potentiometric circuitry to automatically cease application of potential to the electrochemical cell, and then cause the potentiometric circuitry to measure a decay in chemical potential at the electrochemical cell in the absence of the applied potential.
Across the independent claims, the core claim coverage is the combination of controllably applying an external potential to drive an electrochemical cell and measure current, followed by automatic cessation of the applied potential and potentiometric measurement of a decay in chemical potential, with evaluation of analyte measure based on the current and the chemical potential decay.
Stated Advantages
The approach is contrasted with prior art requiring manual mode selection.
The described measurement approach uses automatic control to switch between the measurement phases.
Monitoring of chemical potential relaxation/decay is used to correct analyte-dependent signals.
Documented Applications
Handheld test equipment.
Electrochemical measurement of a measure of an analyte in a bodily fluid.
Measurement in the presence of an analyte of interest.
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