Reference electrode

• US 6,572,748 B1
• Filed: 11/26/2001
• Issued: 06/03/2003
• Est. Priority Date: 03/10/1998
• Status: Expired due to Fees

• Current Assignee: Micronas Gmbh (TDK Corporation)
• Original Assignee: Micronas Gmbh (TDK Corporation)
• Inventors: Herrmann, Sigrun, Kaden, Heiner, Oelssner, Wolfram, Igel, Gunter
• Primary Examiner(s): Bell, Bruce F.
• Application Number:
  US09/623,839
• Time in Patent Office: 554 Days
• Field of Search: 204/435, 204/433, 204/412, 204/408, 204/415, 204/419, 205/775, 205/787.5
• US Class Current: 204/435
• CPC Class Codes: G01N 27/301 Reference electrodes

Abstract

A reference electrode (1) for electrochemical measurements includes a metallic palladium-containing electrode component (3) which is covered by a layer (4) formed of or containing a palladium compound poorly soluble in aqueous media. Positioned on layer (4) is a reference electrolyte (5) which contains anions of this palladium compound in dissolved form (FIG. 4).

Claims

1. Reference electrode (1) for electrochemical measurements, characterized in that it has an electrode component (3) including metallic palladium, that the electrode component (3) is covered by a layer (4) formed of or containing a palladium compound that is poorly soluble in aqueous media, and that a reference electrolyte (5) containing anions of the palladium compound in dissolved form is positioned thereon.

2. Reference electrode according to claim 1, characterized in that the palladium electrode component (3) is formed as a layer positioned on a substrate (2) formed of semiconductor material and that the electrode component (3) is applied to the substrate (2) using a semiconductor-technology production process.

3. Reference electrode according to claim 1, characterized in that the palladium electrode component (3) is formed as a layer which is positioned on a substrate (2) formed of ceramic, glass, glass ceramic, printed-circuit-board material, polymeric material, or similar dielectric material and which is applied to the substrate (2) via thick-film technology.

4. Reference electrode according to claim 3, characterized in that the electrode component (3) contains metallic palladium embedded in finely distributed form in a binder of polymeric material or cermet.

5. Reference electrode according to one of claim 1, characterized in that the poorly soluble palladium compound of layer (4) contains palladium iodide, palladium bromide, and/or palladium acetate.

6. Reference electrode according to one of claim 1, characterized in that the layer (4) exhibiting the poorly soluble palladium compound is produced electrolytically and/or through a chemical precipitation process in situ on the palladium electrode component (3).

7. Reference electrode according to one of claim 1, characterized in that anions of the poorly soluble palladium compound of layer (4) are contained in an ionogenic solution and/or a solidified gel.

8. Reference electrode according to claim 1, characterized in that the electrode is integrated on a semiconductor chip or in a hybrid-structured microsystem.

9. Reference electrode according to one of claim 1, characterized in that the electrode component (3) and/or the layer (4) have a ring-shaped or disk-shaped design or have a rectangular shape.

10. Reference electrode according to claim 1, characterized in that it is a part of an electrochemical measuring system with at least one working electrode (12) located on the substrate (2) and formed of palladium and/or part of an ion-sensitive field effect transistor and that the working electrode (12) and/or the field effect transistor is positioned on the front side of the substrate (2) opposite the palladium electrode component (3).

11. Reference electrode according to one of claim 1, characterized in that at least one temperature sensor is positioned on the substrate (2).

12. Reference electrode according to claim 1, characterized in that the reference electrolyte (5) containing the anions of the palladium compound in dissolved form is covered with a membrane or surface layer (13) perforated at only one point and this point is closed off with a diaphragm (14) conventionally used for electrochemical measurements, but is permeable to an electrolytic compound.

13. Reference electrode according to claim 12, said diaphragm comprising either a porous membrane or a cation-exchange membrane.

14. Method of establishing a reference potential in an amperometric and/or potentiometric measuring circuit comprising the step of:

providing a reference electrode (1) for electrochemical measurements, characterized in that it has an electrode component (3) including metallic palladium, that the electrode component (3) is covered by a layer (4) formed of or containing a palladium compound that is poorly soluble in aqueous media, and that a reference electrolyte (5) containing anions of the palladium compound in dissolved form is positioned thereon; and

,

connecting said electrode in the circuit.