Amperometric flow injection analysis biosensor for glucose based on graphite paste modified with tetracyanoquinodimethane
First Claim
1. An electrode for a biosensor which comprises a homogeneous composition of between about 8 to 15 weight percent of a redox enzyme, between about 28 to 35 weight percent of an electron-transfer mediator, between about 28 to 35 weight percent graphite powder, and between about 23 to 30 weight percent of a mineral oil.
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Abstract
A biosensor system using flow injection analysis (FIA) for the analysis of glucose in human serum. The system utilizes a sensor in which the enzyme glucose oxidase (GOD) is incorporated into graphite paste modified with tetracyanoquinodimethane (TCNQ). TCNQ acts as an efficient mediator for oxidation of the reduced enzyme at 200 mV vs Ag/AgCl. The sensor provides a linear response to glucose over a wide concentration range. The flow injection analysis system has a detection limit of 200 nmol glucose using a 100 μl sample and as been demonstrated to be stable after 800 consecutive sample injections.
20 Citations
19 Claims
- 1. An electrode for a biosensor which comprises a homogeneous composition of between about 8 to 15 weight percent of a redox enzyme, between about 28 to 35 weight percent of an electron-transfer mediator, between about 28 to 35 weight percent graphite powder, and between about 23 to 30 weight percent of a mineral oil.
- 8. In a flow-injection analysis system comprising a pump, an electrochemical cell, a flow line connected between said pump and said electrochemical cell and a sample injector connected to said flow line, the improvement comprising an enzyme electrode for said electrochemical cell which comprises a homogeneous composition of between about 9 to 12 weight percent of a redox enzyme, between about 30 to 33 weight percent of an electron-transfer mediator, between about 30 to 33 weight percent graphite powder, and between about 24 to 28 weight percent of a mineral oil.
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17. A method of measuring glucose concentration in a sample which comprises:
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providing a sample fluid containing glucose; providing an electrochemical cell having a working electrode which comprises a homogeneous composition of between about 8 to 15 weight percent of glucose oxidase, between about 28 to 35 weight percent of tetracyanoquinodimethane, between about 28 to 35 weight percent graphite powder and between about 23 to 30 weight percent of mineral oil; supplying said sample fluid to said electrochemical cell; and measuring glucose concentration in said sample fluid by means of said electrochemical cell. - View Dependent Claims (18, 19)
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Specification