Reference electrode with a polymeric reference electrode membrane

• US 6,793,789 B2
• Filed: 09/22/2001
• Issued: 09/21/2004
• Est. Priority Date: 09/30/2000
• Status: Expired due to Fees

• Current Assignee: Geun Sig Cha
• Original Assignee: Geun Sig Cha
• Inventors: Ha, Jeonghan, Lee, Sung Dong, Lee, Hyo Lin, Oh, Seong Hee, Nam, Hakhyun, Cha, Geun Sig, Shin, Jae Ho, Choi, Yong Suk
• Primary Examiner(s): Olsen, Kaj K.
• Application Number:
  US09/960,432
• Publication Number:
  US 20020065332A1
• Time in Patent Office: 1,095 Days
• Field of Search: 204/435, 204/416, 204/418, 204/419
• US Class Current: 204/435
• CPC Class Codes: G01N 27/301 Reference electrodes

Abstract

Disclosed is a polymeric reference electrode membrane comprising (a) one selected from a porous polymer or a hydrophilic plasticizer; (b) a lipophilic polymer; and optionally an adhesion-enhancing material. A reference electrode equipped with the polymeric reference electrode membrane can be shortened the preconditioning time, and extended lifetime for storage and use owing to excellent adhesion, and showed reproducibility and good yield. So, a miniaturized multi-potentiometric sensor can be fabricated comprising a solid-state reference electrode of the present invention and a set of ion-selective electrodes, thus being useful in the potentiometric fields, including clinical, environmental, food and industrial analysis.

Claims

1. A reference electrode comprising:

a polymeric reference electrode membrane comprising (a) one selected from a cellulose based porous polymer and a hydrophilic plasticizer and (b) a lipophilic polymer, wherein the hydrophilic plasticizer is selected from the group consisting of glycerol, polyethylene glycol, ethylene glycol monomethyl ether, ethylene glycol, formamide and a combination thereof;

an inner reference electrode 3 positioned at the center within the reference electrode; and

an inner reference electrolyte 7 filling the internal space of the reference electrode;

wherein the polymeric reference electrode membrane 8 is mounted to an end of the electrode,

wherein the inner reference electrolyte 7 is a hydrogel obtained by dissolving 1-15% by weight of a hydrophilic polymer in 0.01-3.0 M aqueous solution saturated with a salt selected from the group consisting of KCl, NaCl, KNO3 and NH4NO3, each of which is similar in mobility.

2. The electrode as set forth in claim 1, wherein the polymeric reference electrode membrane 8 comprises a porous polymer and a lipophilic polymer, and the inner reference electrode 3 is made of silver/silver chloride.

3. The electrode as set forth in claim 1, wherein the polymeric reference electrode membrane 8 comprises a hydrophilic plasticizer and a lipophilic polymer, and the inner reference electrode 3 is made of silver/silver chloride.

4. The electrode as set forth in claim 1, wherein the hydrophilic polymer is selected from the group consisting of polyvinylpyrrolidone, polyvinyl alcohol, poly (methyl methacrylate), agar, gelatin.

5. The reference electrode as set forth in claim 1, wherein the lipophilic polymer is selected from the group consisting of silicone rubber, poly (vinyl chloride), polyurethane, poly (vinyl chloride) carboxylated copolymer, poly (vinyl chloride-co-vinyl acetate-co-vinyl alcohol) and a combination thereof.

6. The reference electrode as set forth in claim 1, wherein the polymeric reference electrode membrane comprises 5-70% by weight of the porous polymer and 30-95% by weight of the lipophilic polymer.

7. The membrane as set forth in claim 1, wherein the polymeric reference electrode membrane comprises 10-50% by weight of the porous polymer and 50-90% by weight of the lipophilic polymer.

8. The membrane as set forth in claim 1, wherein the polymeric reference electrode membrane comprises 20-70% by weight of the hydrophilic plasticizer and 30-80% by weight of the lipophilic polymer.

9. The membrane as set forth in claim 1, wherein the polymeric reference electrode membrane further contains an adhesion-enhancing material at an amount of 0.001-1.0% by weight on the total weight of composition.

10. The reference electrode as set forth in claim 9, wherein the adhesion-enhancing material is a highly reactive silicon compound selected from the group consisting of diluted silicon tetrachloride (SiCl₄), aminopropyltriethoxy silane, N-[3(trimethoxysilyl)propyl]ethylenediamine, N(2-aminoethyl)-3-aminopropyltrimethoxy silane, 3-methacryloxypropyltrimethoxy silane, N-(2-vinylbenzylamino)ethyl)-3-aminopropyl trimethoxysilane, 3-glycidoxypropyltrimethoxy silane, methyltrimethoxy silane and phenyltrimethoxy silane.

18. The reference electrode as set forth in claim 1, wherein the porous polymer is selected from the group consisting of cellulose acetate, cellulose acetate butylate, cellulose triacetate, nitro cellulose and a combination thereof.

11. A solid-state reference electrode comprising:

a) a substrate 10;

b) an insulating film layer 9 formed on the substrate;

c) a reference electrode material 11 insulated by the insulating film layer 9; and

d) a polymeric reference electrode membrane 8 protecting the reference electrode material 11, wherein the polymeric reference electrode membrane comprises (a) one selected from a cellulose based porous polymer and a hydrophilic plasticizer and (b) a lipophilic polymer, the hydrophilic plasticizer being selected from the group consisting of glycerol, polyethylene glycol, ethylene glycol monomethyl ether, ethylene glycol, formamide and a combination thereof,

wherein the polymeric reference electrode membrane 8 is additionally fixed to a hydrogel layer 12, thereby the reference electrode material 11 is protected by the polymeric reference electrode membrane and the hydrogel layer and is made of silver/silver chloride 19.

12. The electrode as set forth in claim 11, wherein the polymeric reference electrode membrane is a mono-layer polymeric reference electrode membrane 13 comprising a hydrophilic plasticizer and a lipophilic polymer, and covers the reference electrode material 11, thereby the reference electrode material 11 is protected by the mono-layer and is made of silver/silver chloride.

13. A The electrode as set forth in claim 12, wherein the mono-layer polymeric reference electrode membrane 13 comprises 20-70% by weight of a hydrophilic plasticizer saturated with a salt selected from the group consisting of KCl, NaCl, KNO₃ and NH₄NO₃ and 30-80% by weight of a lipophilic polymer.

14. The electrode as set forth in claim 11, wherein the substrate 10 is made of a material selected from the group consisting of alumina-containing ceramics, silicon, poly (vinyl chloride), polyester, polycarbonate and semiconductor materials.

15. The electrode as set forth in claim 11, wherein the hydrogel layer 12 is prepared by dissolving a hydrophilic polymer at an amount of 1-15% by weight in a 0.01-3.0 M aqueous solution saturated with a salt selected from the group consisting of KCl, NaCl, KNO₃ and NH₄NO₃, each of which is similar in mobility.

16. The electrode as set forth in claim 15, wherein the hydrophilic polymer is selected from the group consisting of polyvinylpyrrolidone, polyvinyl alcohol, poly(methyl methacrylate), agar, gelatin and mixtures thereof.

17. A potentiometric sensor comprising the solid-state reference electrode of claim 11 and a working electrode comprising ion-selective electrodes.

19. The solid-state reference electrode as set forth in claim 11, wherein the porous polymer is selected from the group consisting of cellulose acetate, cellulose acetate butylate, cellulose triacetate, nitro cellulose and a combination thereof.

20. The solid-state reference electrode as set forth in claim 11, wherein the lipophilic polymer is selected from the group consisting of silicone rubber, poly (vinyl chloride), polyurethane, poly (vinyl chloride) carboxylated copolymer, poly (vinyl chloride-co-vinyl acetate-co-vinyl alcohol) and a combination thereof.

21. The solid-state reference electrode as set forth in claim 11, wherein the polymeric reference electrode membrane comprises 5-70% by weight of the porous polymer and 30-95% by weight of the lipophilic polymer.

22. The solid-state reference electrode as set forth in claim 11, wherein the polymeric reference electrode membrane comprises 10-50% by weight of the porous polymer and 50-90% by weight of the liphophilic polymer.

23. The solid-state reference electrode as set forth in claim 11, wherein the polymeric reference electrode membrane comprises 20-70% by weight of the hydrophilic plasticizer and 30-80% by weight of the lipophilic polymer.

24. The solid-state reference electrode as set forth in claim 11, wherein the polymeric reference electrode membrane further contains an adhesion-enhancing material at an amount of 0.001-1.0% by weight on the total weight of composition.

25. The solid-state reference electrode as set forth in claim 24, wherein the adhesion-enhancing material is a highly reactive silicon compound selected from the group consisting of diluted silicon tetrachloride (SiCl₄), aminopropyltriethoxy silane, N-[3(trimethoxysilyl) propyl]ethylenediamine, N(2-aminoethyl)-3-aminopropyltrimethoxy silane, 3-methacryloxypropyltrimethoxy silane, N-(2-vinylbenzylamino)ethyl)-3-aminopropyl trimethoxysilane, 3-glycidoxypropyltrimethoxy silane, methyltrimethoxy silane and phenyltrimethoxy silane.