Polyredox couples in analyte determinations

• US 4,942,127 A
• Filed: 05/06/1988
• Issued: 07/17/1990
• Est. Priority Date: 05/06/1988
• Status: Expired due to Fees

• Current Assignee: Molecular Devices
• Original Assignee: Molecular Devices
• Inventors: Hafeman, Dean G., Wada, Henry G., McConnell, Harden
• Primary Examiner(s): Rosen, Sam
• Application Number:
  US07/191,208
• Time in Patent Office: 802 Days
• Field of Search: 435/11, 435/14, 435/28, 435/25
• US Class Current: 435/11
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: C12Q 1/28 involving peroxidase
• CPC Class Codes: C12Q 2326/12 3,3',5,5'-Tetramethylbenzidine, i.e. TMB
• CPC Class Codes: Y10S 436/806 Electrical property or magnetic property

Abstract

Enzyme or substrate determinations can be achieved by employing an organic second substrate, which produces a product which may be coupled with a metal inorganic redox couple capable of interacting with and affecting the potential of a metal electrode on a semiconductor surface. Particularly, hydrogen peroxide or indoxyl phosphate are coupled with iron- or ruthenium-containing ionic redox couples for determination with a noble metal electrode.

Claims

1. In a method for determining the presence of an oxidase by means of employing a metal electrode for detection of a redox reaction in an assay medium, the improvement which comprises:

employing for detection in combination;

(1) a tetramethylbenzidine and hydrogen peroxide;

with

(2) an iron- or ruthemium-containing ionic redox couple in which said iron is in a coordinated form capable of undergoing one electron transfer and said ruthenium is coordinated with a nitrogen ligand

2. A method according to claim 11, wherein said oxidase is horseradish peroxidase and said hydrogen peroxide is produced by an enzymatic reaction during said assay.

3. A method according to claim 11 wherein said oxidase is horseradish peroxidase and said hydrogen peroxide is produced by the reaction of cholesterol oxidase or glucose oxidase.

4. A method according to claim 11, wherein said iron-containing ionic redox couple is the hexacyanoferrate redox couple.

5. A method according to claim 11, wherein said ruthenium-containing ionic redox couple is present as ruthenium pentaamine pyridine.

6. A method for determining cholesterol in a sample employing a metal electrode for detection of a redox reaction in an assay medium, said method comprising:

combining said sample, cholesterol oxidase, horseradish peroxidase and tetramethylbenzidine with an iron- or ruthenium-containing ionic redox couple in which said iron is in a coordinated form capable of undergoing one electron transfer and said ruthenium is coordinated with a nitrogen ligand in an assay medium; and

determining by means of a metal electrode the redox reaction in said assay medium and relating said reaction to a medium having a known amount of cholesterol.

7. A method for determining glucose in a sample employing a metal electrode for detection of a redox reaction in an assay medium, said method comprising:

combining said sample, glucose oxidase, horseradish peroxidase and tetramethylbenzidine with an iron- or ruthenium-containing ionic redox couple in which said iron is in a coordinated form capable of undergoing one electron transfer and said ruthenium is coordinated with a nitrogen ligand in an assay medium; and

determining by means of a metal electrode the redox reaction in said assay medium and relating said reaction to a medium having a known amount of glucose.