Polyredox couples in analyte determinations

• US 5,501,956 A
• Filed: 01/24/1994
• Issued: 03/26/1996
• Est. Priority Date: 03/23/1990
• Status: Expired due to Fees

• Current Assignee: Molecular Devices
• Original Assignee: Molecular Devices
• Inventors: Wada, Henry G., Hafeman, Dean G., McConnell, Harden M.
• Primary Examiner(s): Gitomer, Ralph J.
• Application Number:
  US08/185,730
• Time in Patent Office: 792 Days
• Field of Search: 435/7.95, 435/11, 435/18, 435/21, 435/25, 435/14, 435/28, 435/817, 204/153.12, 204/403
• US Class Current: 205/777.5
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/26 involving oxidoreductase
• CPC Class Codes: C12Q 1/28 involving peroxidase
• CPC Class Codes: C12Q 1/42 involving phosphatase
• CPC Class Codes: C12Q 1/60 involving cholesterol
• CPC Class Codes: C12Q 2326/12 3,3',5,5'-Tetramethylbenzidine, i.e. TMB
• CPC Class Codes: C12Q 2334/52 5-Bromo-4-chloro-3-indolyl, i.e. BCI
• CPC Class Codes: Y10S 435/817 Enzyme or microbe electrode

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 in an assay medium by employing a metal electrode for detection of a redox reaction, the improvement which comprises:

(a) a tetramethylbenzidine and hydrogen peroxide;

with

(b) an iron or ruthenium containing ionic redox couple in the assay medium.

2. A method according to claim 1, wherein said oxidase is horseradish peroxidase and said hydrogen peroxide is produced in said assay medium by the enzymatic reaction of said oxidase with a substrate for the oxidase in said assay medium.

3. A method according to claim 1, wherein said oxidase is horseradish peroxidase and said hydrogen peroxide is produced in the assay medium by a reaction of cholesterol oxidase or glucose oxidase with a substrate for the oxidase.

4. A method according to claim 1, wherein said iron containing ionic redox couple is hexacyanoferrate redox couple.

5. A method according to claim 1, wherein said ruthenium containing ionic redox couple is ruthenium pentamine complex.

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

(a) a benzidine and hydrogen peroxide;

with

(b) an ionic redox couple containing an element selected from the group consisting of iron and ruthenium in the assay medium.

7. A method according to claim 6, wherein the metal is a noble metal.

8. A method according to claim 6, wherein the hydrogen peroxide is produced in the assay medium by an enzymatic reaction in the assay medium.

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

(a) a tetramethylbenzidine and hydrogen peroxide, with

(b) an ionic redox couple containing an element selected from the group consisting of iron and ruthenium in the assay medium.

10. A method according to claim 9, wherein the oxidase is horseradish peroxidase and the hydrogen peroxide is produced in the assay medium by an enzymatic reaction in the assay medium during the assay.

11. A method according to claim 9, wherein the oxidase is horseradish peroxidase and the hydrogen peroxide is produced in the assay medium by a reaction of cholesterol oxidase or glucose oxidase with a substrate for the oxidase.

12. A method according to claim 9, wherein the ionic redox couple containing iron is a hexacyanoferrate redox couple.

13. A method according to claim 9, wherein the ionic redox couple containing ruthenium is a ruthenium pentamine pyridine redox couple.

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

(a) a compound selected from the group consisting of indoxyl ester and other;

with

(b) an ionic redox couple containing an element selected from the group consisting of iron and ruthenium in the assay medium.

15. A method according to claim 14, wherein the ionic redox couple containing ruthenium is ruthenium pentamine pyridine redox couple.

16. A method according to claim 14, wherein the ionic redox couple containing iron is a hexacyanoferrate redox couple.

17. A method according to claim 14, wherein the hydrolase is alkaline phosphatase and the indoxyl ester is indoxyl phosphate.