Apparatus and method for measuring concentration of an analyte in whole blood samples
First Claim
1. A method for measuring a concentration of an analyte in a bio-sample, the method comprising:
- a step of introducing a liquid bio-sample into a sample cell in which an oxidation/reduction enzyme capable of catalyzing an oxidation/reduction reaction of the analyte and an electron transfer mediator are fixed and a working electrode and a counter electrode are provided;
a step of obtaining a first induced current by applying a constant DC voltage to the working electrode to start the oxidation/reduction reaction of the analyte and proceed with an electron transfer reaction;
a step of obtaining a second induced current by applying a Λ
-step ladder-type perturbation potential after applying the constant DC voltage, wherein the step of obtaining the second induced current is subsequent to the step of obtaining the first induced current;
a step of calculating a predetermined feature from two or more characteristic points from the first induced current or the second induced current; and
a step of calculating a concentration of the analyte using a calibration equation formed of at least one feature function so as to minimize an effect of at least one hindering material in the bio-sample, wherein the at least one feature function comprises a function using the first induced current obtained from the constant DC voltage and a function using the second induced current obtained from the Λ
-step ladder-type perturbation potential,wherein the Λ
-step ladder-type perturbation potential is characterized by a height (Vstep) of each step, an application time (tstep) for each step, a difference (Vcenter) between a middle voltage and the constant DC voltage in an entire range of variations, a difference (Vpeak) between a middle voltage and a peak voltage, and a time difference (tcycle) between a peak voltage of an entire step ladder-type wave and a peak voltage of an adjacent next step ladder-type wave,wherein the constant DC voltage and the Λ
-step ladder-type perturbation potential are applied to the working electrode through a same digital-to-analog converter circuit linked with a microcontroller, andwherein a characteristic point, having different linearity with respect to the analyte and the hindering material, is selected from the first or second induced current, wherein a feature is formed of the characteristic point, and wherein a calibration equation is formed of the feature.
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Abstract
A method for measuring a concentration of an analyte in a bio-sample using an electrochemical bio-sensor according to an exemplary embodiment of the present invention is characterized by a step of obtaining predetermined features from induced currents obtained by applying a DC voltage according to chronoamperometry in which, after a whole blood sample is injected to the electrochemical bio-sensor, a concentration of an analyte is obtained from an induced current obtained by applying a DC voltage for a certain time and from all induced currents obtained by further applying several step-ladder perturbation potentials for a short time subsequent to the DC voltage for the certain time, and is also characterized by minimization of a measurement error caused by a hindering material by forming a calibration equation by combining the at least one feature in a function and optimizing various conditions of the bio-sample through DeletedTextsmultivariable analysis. With this configuration, a perturbation potential application method added to a conventional measurement method can maintain a bio-sensor and a measuring apparatus already used, a line used in the measuring apparatus, and calibration of amperometry as they are, improve accuracy in measurement by effectively minimizing a matrix interference effect of a background material in a bio-sample, particularly an inaccuracy caused by a change in hematocrit, and also remarkably improve accuracy in measurement by simply upgrading a measurement program of a conventional measuring apparatus.
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Citations
11 Claims
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1. A method for measuring a concentration of an analyte in a bio-sample, the method comprising:
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a step of introducing a liquid bio-sample into a sample cell in which an oxidation/reduction enzyme capable of catalyzing an oxidation/reduction reaction of the analyte and an electron transfer mediator are fixed and a working electrode and a counter electrode are provided; a step of obtaining a first induced current by applying a constant DC voltage to the working electrode to start the oxidation/reduction reaction of the analyte and proceed with an electron transfer reaction; a step of obtaining a second induced current by applying a Λ
-step ladder-type perturbation potential after applying the constant DC voltage, wherein the step of obtaining the second induced current is subsequent to the step of obtaining the first induced current;a step of calculating a predetermined feature from two or more characteristic points from the first induced current or the second induced current; and a step of calculating a concentration of the analyte using a calibration equation formed of at least one feature function so as to minimize an effect of at least one hindering material in the bio-sample, wherein the at least one feature function comprises a function using the first induced current obtained from the constant DC voltage and a function using the second induced current obtained from the Λ
-step ladder-type perturbation potential,wherein the Λ
-step ladder-type perturbation potential is characterized by a height (Vstep) of each step, an application time (tstep) for each step, a difference (Vcenter) between a middle voltage and the constant DC voltage in an entire range of variations, a difference (Vpeak) between a middle voltage and a peak voltage, and a time difference (tcycle) between a peak voltage of an entire step ladder-type wave and a peak voltage of an adjacent next step ladder-type wave,wherein the constant DC voltage and the Λ
-step ladder-type perturbation potential are applied to the working electrode through a same digital-to-analog converter circuit linked with a microcontroller, andwherein a characteristic point, having different linearity with respect to the analyte and the hindering material, is selected from the first or second induced current, wherein a feature is formed of the characteristic point, and wherein a calibration equation is formed of the feature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification