US4933048A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reference electrode, method of making and method of using same
Assignee: Abbott Point of Care Inc
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Filing: 1988-02-16
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Granted: 1990-06-12
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Expires: 2008-02-16
Abstract
Abstract An improved reference electrode is disclosed for use in potentiometric measurements of the amount of ions in an aqueous solution. The reference electrode illustratively comprises a metal member on a substrate, and a layer of a salt reversible to the ion X overlying the metal member. The reference electrode is overlaid by a quantity of an electrolyte, which may be a polymer gel having a salt including the ion X dispersed therein. This structure is overlaid by a membrane permeable to water but not to the ion X that extends beyond the portion of the electrolyte overlying the electrode, but leaves a portion of the electrolyte exposed. This assembly may be shipped dry. In use, when the electrode is disposed in an aqueous solution containing an ionic species to be measured, water permeates the membrane and "wets up" the electrolyte relatively quickly. Any changes in ionic concentration, however, have to be made over a substantially longer path through the electrolyte between the electrode and the exposed portion such that the transit time for such changes is substantially longer than the wet-up time of the electrolyte. This reference electrode may be used in combination with a wide variety of potentiometric indicating electrodes or other structures.
Inventors
- 👤 Imants R. Lauks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:42
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/28; G01N27/30; G01N27/301
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
180 words
A reference electrode assembly comprising: an electrode comprising an outer layer of a material reversible to a chemical species, said electrode being disposed on a substrate; a first layer of an electrolyte material covering all portions of said electrode not in contact with said substrate and extending beyond the perimeter of said electrode; and a second layer of material impermeable to said chemical species but permeable to water extending over a portion of said electrolyte layer beyond the perimeter of said electrode, such that when said electrode contacts an aqueous solution a first portion of the surface of the electrolyte over the electrode and extending beyond the perimeter of said electrode is contacted by water but is sealed with respect to said chemical species and a liquid junction is formed at a remaining exposed second portion of the surface of the electrolyte; and wherein the distance in the electrolyte between the exposed second portion of the surface of said electrolyte material and the electrode is large compared to the distance in the electrolyte between the impermeable layer and the electrode.
Claim 2
Dependent Claim
180 words
A reference electrode assembly comprising: an electrode comprising an outer layer of a material reversible to a chemical species, said electrode being disposed on a substrate; a first layer of an electrolyte material covering all portions of said electrode not in contact with said substrate and extending beyond the perimeter of said electrode; and a second layer of material impermeable to said chemical species but permeable to water extending over a portion of said electrolyte layer beyond the perimeter of said electrode, such that when said electrode contacts an aqueous solution a first portion of the surface of the electrolyte over the electrode and extending beyond the perimeter of said electrode is contacted by water but is sealed with respect to said chemical species and a liquid junction is formed at a remaining exposed second portion of the surface of the electrolyte; and wherein the distance in the electrolyte between the exposed second portion of the surface of said electrolyte material and the electrode is large compared to the distance in the electrolyte between the impermeable layer and the electrode.
Claim 3
Dependent Claim
16 words
A reference electrode of claim 1 wherein said electrode is formed by thin film fabrication techniques.
Claim 4
Dependent Claim
13 words
The reference electrode assembly of claim 1 wherein said electrode is generally planar.
Claim 5
Dependent Claim
40 words
The reference electrode assembly of claim 1 wherein said electrode comprises a metal portion in contact with said substrate and said outer layer is of a salt or a compound of said metal which is reversible to said chemical species.
Claim 6
Dependent Claim
27 words
The reference electrode assembly of claim 4 wherein said chemical species is Cl - , the metal portion is Ag and the overlying outer layer is AgCl.
Claim 7
Dependent Claim
17 words
The reference electrode assembly of claim 4 wherein said electrolyte is a material having KCl dispersed therein.
Claim 8
Dependent Claim
20 words
The reference electrode assembly of claim 1 wherein said second layer is formed of PVC, PTFE, or silicone rubber material.
Claim 9
Dependent Claim
191 words
In combination, a reference electrode assembly and a working electrode, the reference electrode assembly comprising: an electrode having an outer layer of a material reversible to a chemical species, said electrode being disposed on a substrate; a first layer of an electrolyte material covering all portions of said electrode not in contact with said substrate and extending beyond the perimeter of said electrode; and a second layer of material impermeable to said chemical species but permeable to water extending over a portion of said electrolyte layer beyond the perimeter of said electrode, such that when said electrode contacts an aqueous solution a first portion of the surface of the electrolyte over the electrode and extending beyond the perimeter of said electrode is contacted by water but is sealed with respect to said chemical species and a liquid junction is formed at a remaining exposed second portion of the surface of the electrolyte, and such that the distance in the electrolyte between the exposed second portion of the surface of said electrolyte material and the electrode is large compared to the distance in the electrolyte between the impermeable layer and the electrode.
Claim 10
Dependent Claim
191 words
In combination, a reference electrode assembly and a working electrode, the reference electrode assembly comprising: an electrode having an outer layer of a material reversible to a chemical species, said electrode being disposed on a substrate; a first layer of an electrolyte material covering all portions of said electrode not in contact with said substrate and extending beyond the perimeter of said electrode; and a second layer of material impermeable to said chemical species but permeable to water extending over a portion of said electrolyte layer beyond the perimeter of said electrode, such that when said electrode contacts an aqueous solution a first portion of the surface of the electrolyte over the electrode and extending beyond the perimeter of said electrode is contacted by water but is sealed with respect to said chemical species and a liquid junction is formed at a remaining exposed second portion of the surface of the electrolyte, and such that the distance in the electrolyte between the exposed second portion of the surface of said electrolyte material and the electrode is large compared to the distance in the electrolyte between the impermeable layer and the electrode.
Claim 11
Dependent Claim
17 words
The combination of claim 8 wherein said reference and working electrodes are formed on a common substrate.
Claim 12
Dependent Claim
15 words
The combination of claim 8 wherein said electrodes are formed using thin film fabrication techniques.
Claim 13
Dependent Claim
209 words
A reference electrode assembly comprising: an electrode comprising an outer layer of a material reversible to a chemical species, said electrode being disposed on a substrate; a first layer of an electrolyte material covering all portions of said electrode not in contact with said substrate and extending beyond the perimeter of said electrode; and a second layer of material permeable to water but impermeable to any chemical species present in said electrolyte material or in a solution in which the reference electrode is used whose concentration affects a potential developed at said electrode, said second layer extending over a portion of said electrolyte layer extending beyond the perimeter of said electrode, such that when said electrode contacts an aqueous solution a first portion of the surface of the electrolyte over the electrode and extending beyond the perimeter of said electrode is contacted by water but is sealed with respect to said chemical species and a liquid junction is formed at a remaining exposed second portion of the surface of the electrolyte; and wherein the distance in the electrolyte between the exposed second portion of the surface of said electrolyte material and the electrode is large compared to the distance in the electrolyte between the impermeable layer and the electrode.
Claim 14
Dependent Claim
209 words
A reference electrode assembly comprising: an electrode comprising an outer layer of a material reversible to a chemical species, said electrode being disposed on a substrate; a first layer of an electrolyte material covering all portions of said electrode not in contact with said substrate and extending beyond the perimeter of said electrode; and a second layer of material permeable to water but impermeable to any chemical species present in said electrolyte material or in a solution in which the reference electrode is used whose concentration affects a potential developed at said electrode, said second layer extending over a portion of said electrolyte layer extending beyond the perimeter of said electrode, such that when said electrode contacts an aqueous solution a first portion of the surface of the electrolyte over the electrode and extending beyond the perimeter of said electrode is contacted by water but is sealed with respect to said chemical species and a liquid junction is formed at a remaining exposed second portion of the surface of the electrolyte; and wherein the distance in the electrolyte between the exposed second portion of the surface of said electrolyte material and the electrode is large compared to the distance in the electrolyte between the impermeable layer and the electrode.
Claim 15
Independent Claim
216 words
A method for measuring a signal responsive to the concentration of an chemical species in an aqueous solution, comprising the steps of: manufacturing a reference electrode assembly, said assembly comprising an electrode on a substrate, said electrode being surrounded by a dry electrolyte, a portion of said electrolyte extending over said electrode beyond the perimeter of said electrode being covered by a layer of material permeable to water and impermeable to any chemical species present in said solution or in said electrolyte whose concentration affects a potential developed at said electrode, another portion of said electrolyte being exposed, such that the distance in said electrolyte from said layer of material to said electrode is less than the distance in said electrolyte from the exposed portion of the electrolyte to the electrode; assembling the reference electrode assembly together with a working electrode, and connecting said electrodes to means for measuring the voltage therebetween; placing said reference electrode assembly and said working electrode in contact with an aqueous solution containing the chemical species whose concentration is to be measured, whereby the electrolyte wets-up faster than concentration changes takes place in the electrolyte as a result of migration between the exposed portion of the electrolyte and the electrode; and monitoring the potential difference between said reference and working electrodes.
Claim 16
Independent Claim
216 words
A method for measuring a signal responsive to the concentration of an chemical species in an aqueous solution, comprising the steps of: manufacturing a reference electrode assembly, said assembly comprising an electrode on a substrate, said electrode being surrounded by a dry electrolyte, a portion of said electrolyte extending over said electrode beyond the perimeter of said electrode being covered by a layer of material permeable to water and impermeable to any chemical species present in said solution or in said electrolyte whose concentration affects a potential developed at said electrode, another portion of said electrolyte being exposed, such that the distance in said electrolyte from said layer of material to said electrode is less than the distance in said electrolyte from the exposed portion of the electrolyte to the electrode; assembling the reference electrode assembly together with a working electrode, and connecting said electrodes to means for measuring the voltage therebetween; placing said reference electrode assembly and said working electrode in contact with an aqueous solution containing the chemical species whose concentration is to be measured, whereby the electrolyte wets-up faster than concentration changes takes place in the electrolyte as a result of migration between the exposed portion of the electrolyte and the electrode; and monitoring the potential difference between said reference and working electrodes.
Claim 17
Dependent Claim
27 words
The method of claim 12 comprising the further step of calibrating said assembly by exposure thereof to a reagent having a predetermined concentration of said chemical species.
Claim 18
Independent Claim
143 words
A method of manufacture of a working electrode and reference electrode assembly, comprising the steps of: depositing layers forming a working electrode and a conductor for a reference electrode on a substrate; forming a layer of a material reversible to a chemical species over the conductor, thus forming a reference electrode; depositing a layer of a dry electrolyte over said reference electrode; and forming a layer of a material permeable to water and impermeable to said chemical species over said layer of electrolyte, such that an exposed portion of said layer of electrolyte beyond the perimeter of the reference electrode is not covered by said layer of material; wherein the distance through said electrolyte between said layer of material and said reference electrode is small compared to the distance through said electrolyte between the exposed portion of said electrolyte and said reference electrode.
Claim 19
Independent Claim
143 words
A method of manufacture of a working electrode and reference electrode assembly, comprising the steps of: depositing layers forming a working electrode and a conductor for a reference electrode on a substrate; forming a layer of a material reversible to a chemical species over the conductor, thus forming a reference electrode; depositing a layer of a dry electrolyte over said reference electrode; and forming a layer of a material permeable to water and impermeable to said chemical species over said layer of electrolyte, such that an exposed portion of said layer of electrolyte beyond the perimeter of the reference electrode is not covered by said layer of material; wherein the distance through said electrolyte between said layer of material and said reference electrode is small compared to the distance through said electrolyte between the exposed portion of said electrolyte and said reference electrode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |