Method and apparatus using solid sensor electrode

• US 3,929,609 A
• Filed: 01/08/1975
• Issued: 12/30/1975
• Est. Priority Date: 01/31/1973
• Status: Expired due to Term

• Current Assignee: Kimble Glass, Inc. (Corning Incorporated)
• Original Assignee: Don N. Gray, George G. Guilbault
• Inventors: Gray, Don N., Guilbault, George G.
• Primary Examiner(s): Tung, T.
• Application Number:
  US05/539,268
• Time in Patent Office: 356 Days
• Field of Search: 204/1T,195T,195R,280,286,29R,292,297R 23/23R,232E,232R,253R,254E,254R
• US Class Current: 205/788.5
• CPC Class Codes: G01N 31/164 by electrical or electrochemical means
• CPC Class Codes: Y10T 436/116664 with automated titrator

Abstract

A noble metal-glass composite is screen printed on an inert substrate such as a low alkali glass and fired to provide a solid sensor electrode.

Claims

1. In an electrochemical cell for electrochemically determining the end point of a titration reaction, said cell comprising a vessel adapted to contain a titrate, a reference electrode, and a noble metal electrode having a sensing surface exposed for direct contact with said titrate, said reference electrode and said noble metal electrode adapted to be in electrical communication through said titrate and electrically connected to an electrometer through a circuit external from said titrate;

the improvement wherein said noble metal electrode sensing surface comprises the composite, solid-state, fusion product of a mixture of noble metal powder and powdered glass, fused to inert substrate.

2. The cell of claim 1 wherein said sensing surface comprises about from 50% to 99% by weight of noble metal.

3. The cell of claim 1 wherein said noble metal is gold, silver, platinum, palladium or a mixture thereof.

4. The cell of claim 1 wherein said substrate is glass.

5. The cell of claim 1 wherein said substrate is a low alkali glass.

6. The cell of claim 5 wherein said low alkali glass contains about 44.9% SiO2, 19.0% Al2O3, 15.1% MgO and 21.0% CaO.

7. The cell of claim 1 wherein said substrate is alumina.

8. The cell of claim 1 wherein the glass present in said composite is a low alkali glass.

9. IN THE METHOD FOR ELECTROCHEMICALLY DETERMINING THE END POINT OF A TITRATION WHEREIN A TITRANT IS ADDED TO A TITRATE AND THE TITRATION IS ELECTROCHEMICALLY MONITORED USING A REFERENCE ELECTRODE AND A NOBLE METAL ELECTRODE HAVING A SENSING SURFACE IN DIRECT CONTACT WITH SAID TITRATE, THE IMPROVEMENT WHEREIN SAID NOBLE METAL ELECTRODE HAS A SENSING SURFACE COMPRISING THE COMPOSITE, SOLIDSTATE, FUSION PRODUCT OF A MIXTURE OF NOBLE METAL POWDER AND POWDERED GLASS, FUSED TO AN INERT SUBSTRATE

10. The method of claim 9 wherein said sensing surface comprises about from 50% to 99% by weight of noble metal.

11. The method of claim 9 wherein said noble metal is gold, silver, platinum, palladium or a mixture thereof.

12. The method of claim 9 wherein said substrate is glass.

13. The method of claim 9 wherein said substrate is a low alkali glass.

14. The method of claim 13 wherein said low alkali glass contains about 44.9% SiO2, 19.0% Al2O3, 15.1% MgO and 21.0% CaO.

15. The method of claim 9 wherein said substrate is alumina.

16. The method of claim 9 wherein the glass present in said composite is a low alkali glass.