US5378332A
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US
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Amperometric flow injection analysis biosensor for glucose based on graphite paste modified with tetracyanoquinodimethane
Assignee: United States Department of Commerce
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Filing: 1993-04-14
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Granted: 1995-01-03
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Expires: 2013-04-14
Abstract
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.
Inventors
- 👤 Prem C. Pandey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:36
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/001; C12Q1/005; C12Q1/006; C12Q1/004; Y; Y10; Y10S; Y10S435/00; Y10S435/817
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
54 words
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.
Claim 2
Dependent Claim
54 words
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.
Claim 3
Dependent Claim
16 words
An electrode for a biosensor according to claim 1, wherein said redox enzyme comprises glucose oxidase.
Claim 4
Dependent Claim
15 words
An electrode for a biosensor according to claim 2 wherein said electron-transfer mediator comprises tetracyanoquinodimethane.
Claim 5
Dependent Claim
16 words
An electrode for a biosensor according to claim 2 wherein said mineral oil is Nujol oil.
Claim 6
Dependent Claim
23 words
An electrode for a biosensor according to claim 2, wherein said mineral oil has a density of between about 0.83 and 0.85 g/mL.
Claim 7
Dependent Claim
22 words
An electrode for a biosensor according to claim 2, wherein said graphite powder has a particle size of less than 10 microns.
Claim 8
Dependent Claim
17 words
An electrode for a biosensor according to claim 1, wherein said composition is held in a support.
Claim 9
Dependent Claim
90 words
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.
Claim 10
Dependent Claim
90 words
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.
Claim 11
Dependent Claim
15 words
A flow-injection analysis system according to claim 8, wherein said redox enzyme comprises glucose oxidase.
Claim 12
Dependent Claim
14 words
A flow-injection analysis system according to claim 9, wherein said electron-transfer mediator comprises tetracyanoquinodimethane.
Claim 13
Dependent Claim
15 words
A flow-injection analysis system according to claim 9, wherein said mineral oil comprises Nujol oil.
Claim 14
Dependent Claim
22 words
A flow-injection analysis system according to claim 9, wherein said mineral oil has a density of between about 0.83 and 0.85 g/mL.
Claim 15
Dependent Claim
19 words
A flow-injection analysis system according to claim 12, wherein said mineral oil has a density of about 0.838 g/mL.
Claim 16
Dependent Claim
21 words
A flow-injection analysis system according to claim 9, wherein said graphite powder has a particle size of less than 10 microns.
Claim 17
Dependent Claim
20 words
A flow-injection analysis system according to claim 14, wherein said graphite powder has a particle size of between 1-2 microns.
Claim 18
Dependent Claim
16 words
A flow-injection analysis system according to claim 8, wherein said composition is held in a support.
Claim 19
Independent Claim
92 words
A method of measuring glucose concentration in a sample which comprises: 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.
Claim 20
Independent Claim
92 words
A method of measuring glucose concentration in a sample which comprises: 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.
Claim 21
Dependent Claim
37 words
A method of measuring glucose concentration in a sample according to claim 17, wherein said electrochemical cell comprises a flow cell and said sample fluid is supplied to said electrochemical cell by means of a flow-injection system.
Claim 22
Dependent Claim
19 words
A method of measuring glucose concentration in a sample according to claim 17, wherein said sample comprises blood serum.
References Cited (Backward Citations)
US5089112A
Cited
US5240571A
Cited
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