GB2289541A - pH sensor - Google Patents
pH sensor Download PDFInfo
- Publication number
- GB2289541A GB2289541A GB9410859A GB9410859A GB2289541A GB 2289541 A GB2289541 A GB 2289541A GB 9410859 A GB9410859 A GB 9410859A GB 9410859 A GB9410859 A GB 9410859A GB 2289541 A GB2289541 A GB 2289541A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sensor
- conductive layer
- metal
- oxide
- region
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 229910052751 metal Inorganic materials 0.000 claims abstract description 19
- 239000002184 metal Substances 0.000 claims abstract description 19
- 239000011159 matrix material Substances 0.000 claims abstract description 18
- 239000000758 substrate Substances 0.000 claims abstract description 10
- 239000003822 epoxy resin Substances 0.000 claims abstract description 9
- 229920000647 polyepoxide Polymers 0.000 claims abstract description 9
- 229920000642 polymer Polymers 0.000 claims abstract description 7
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000010931 gold Substances 0.000 claims abstract description 6
- 229910052741 iridium Inorganic materials 0.000 claims abstract description 5
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 5
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 4
- 238000004891 communication Methods 0.000 claims abstract description 4
- 229910052737 gold Inorganic materials 0.000 claims abstract description 4
- 229910001925 ruthenium oxide Inorganic materials 0.000 claims abstract description 4
- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical compound O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 claims abstract description 4
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 3
- 239000011195 cermet Substances 0.000 claims abstract description 3
- 229910001020 Au alloy Inorganic materials 0.000 claims abstract 2
- 229910001260 Pt alloy Inorganic materials 0.000 claims abstract 2
- 239000007788 liquid Substances 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- 238000012544 monitoring process Methods 0.000 claims description 4
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 claims description 3
- 229910000457 iridium oxide Inorganic materials 0.000 claims description 3
- 229910052723 transition metal Inorganic materials 0.000 claims description 3
- 150000003624 transition metals Chemical class 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 abstract description 10
- 229910052697 platinum Inorganic materials 0.000 abstract description 5
- 239000002131 composite material Substances 0.000 abstract description 3
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 abstract description 2
- 229910052787 antimony Inorganic materials 0.000 abstract description 2
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 abstract description 2
- 229910052762 osmium Inorganic materials 0.000 abstract description 2
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 abstract description 2
- 229910052707 ruthenium Inorganic materials 0.000 abstract description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 abstract 2
- 229910052763 palladium Inorganic materials 0.000 abstract 1
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 1
- 241000206607 Porphyra umbilicalis Species 0.000 description 1
- 229910002090 carbon oxide Inorganic materials 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/28—Electrolytic cell components
- G01N27/30—Electrodes, e.g. test electrodes; Half-cells
- G01N27/333—Ion-selective electrodes or membranes
- G01N27/3335—Ion-selective electrodes or membranes the membrane containing at least one organic component
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Molecular Biology (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
A pH sensor comprising an insulative substrate 1, a conductive layer 2 supported on the substrate, a first terminal region 2a which forms a part of the conductive layer and which is arranged to provide for an electrical connection to the sensor, a second region 2b of the conductive layer overlaid by a filled polymer matrix 5 arranged in electrical communication with the conductive layer via a region of metal 4, the oxide of which is pH sensitive, the matrix 5 being filled with this pH sensitive metal oxide, and an insulative layer 3 which masks the surface of the conductive layer between the said first terminal region and the second region. The metal region 4 is preferably of iridium but may be antimony, osmium, palladium, ruthenium or platinum. The conductive layer 2 may be gold, platinum, a gold/platinum alloy or composite, carbon or a conductive oxide such as ruthenium oxide. The substrate may be alumina and the insulative layer epoxy resin or a cermet. The polymer matrix 5 which incorporates the metal oxide may be of epoxy resin. <IMAGE>
Description
IMPROVENIENTS IN OR RELATING TO SENSORS
This invention relates to sensors and more especially it relates to sensors for measuring the pH of liquids, such as water.
for example.
Water quality monitol ing apparatus which uses a pH sensor is described in our co-pending GB patent application number 9324663.5, to which attention is hereby directed.
It is important that pH sensors for water quality monitoring should have repeatable characteristics and it is also advantageous that they should be simple and reasonably inexpensive to manufacture.
Accordingly it is an object of the present invention to provide a sensor suitable for monitoring the pH of water, which
sensor has predictable characteristics and may be easily
manufactured.
According to the present invention a pH sensor comprises
an insulative substrate, a conductive layer supported on the said
substrate. a first terminal region which forms a part of the said
conductive layer and which is arranged to provide for an electrical
connection to the sensor, a second region of the said conductive
layer overlaid by a filled polymer matrix arranged in electrical
communication with the said conductive layer via a region of
metal the oxide of which is plA sensitive the said matrix being
filled with this pH sellsitive metal oxide, and an insulative laver which serves to mask a surface of the conductive layer between
the said first terminal region and the said second region.
The region of metal the oxide of which is pH sensitive may be a metal in the transition series of the periodic table.
In use of the sensor, the filled matrix is exposed to a liquid, the pH of which is required to be sensed, an electrical path through the liquid to the terminal region being completed.
whereby the pH of the liquid is indicated in dependence upon the electrical characteristics of the said path.
The conductive layer mav be a metal layer such as gold and/or platinum composite or alloy carbon, or a conductive oxide material such as a ruthenium oxide applied as a paste.
The said metal region may be iridium. the matrix being filled with iridium oxide.
In alternative arrangements however, the metal region might be antimony. osmium. paladiuno. ruthenium. or platinum for example. the matrix being filled with a corresponding oxide of the metal chosen.
The substrate may be made of alumina.
The matrix may be an epoxy resin or other polvmeric matrix material.
The insulative layer may also he an epoxy resin or a cermet material or other dielectric material.
Some embodiments of the in\-ention will now be described hv wav of example only with reference to the accompanying drawings, wherein.
FIGURE 1 is a plan view of a pH sensor device: FIGURE 2 is a side view of the device as shown in Figure 1 hearing. as appropriate. the same numerical designations, and FIGURE 3 is a graph which illustrates a linear operating characteristic associated with the device as shown in Figure 1 and
Figure 2.
Referring now to the drawings, the device comprises an insulative substrate 1, which in this example is made of alumina ceramic, on which a metal layer 2 is supported. The metal layer may be made of gold or platinum or an alloy or composite of these two metals or of other conductive material. e.g. carbon or ruthenium oxide. One region 2a of the metal layer is arranged to serve as a terminal to provide for electrical connection to the sensor device. The terminal may be formed fi-om a further metal layer that permits soldering or facilitates other means of electrical contact.A second region 2b of the layer 2 is separated from the terminal region 2a by insulating material which in this example is an epoxy resin dielectric layer 3 which serves to mask a surface of the layer 2 between the regions 2a and 2b. The second region b is overlaid by a polymer matrix 5 which might be an epoxy resin.
a phenolic resin or any other suitable material which can be mixed with a metal oxide and which can be printed and cured as necessary. The polymer matrix 5 is filled with iridium oxide and arranged in electrical communication with the region 2b of the layer 2 via a layer 4 of iridium. Although iridium is used in this example. any other suitable transition metal may alternatively be used. the matrix 5 being filled with a coiresponding pH sensitive oxide of the metal chosen.
In use of the pH sensor a region enclosed by a broken line 6 is exposed to a liquid the pH of which is required to be sensed.
Thus it will be apparent that these is an electrical path through the liquid to the terminal region 2a via the filled polymer matrix 5 and the layer 4 of transition metal.
As can be seen from Figul e 3* the device provides linear operating characteristics over a wide range of pH values, and additionally the device may simply and inexpensively be manufactured by thick film techniques which are well known to those skilled in the art.
Various modifications may be made to the sensor as hereinbefore described without departing from the scope of the invention, and for example. although in the foregoing embodiment the layer 4 is deposited befoi-e the epoxy resin dielectric layer 3, in an alternative embodiment the layer 3 may be deposited first and overlaid by the layer A. If the dielectric layer 3 is deposited before the layer 4 it could comprise a ceramic material.
Claims (15)
1. A pH sensor comprising an insulative substrate, a conductive layer supported on the said substrate, a first terminal legion which forms a part of the said conductive layer and which is arranged to provide for an electrical connection to the sensor. a second region of the said conductive layer overlaid by a filled polymer matrix arranged in electrical communication with the said layer via a legion of metal the oxide of which is pH sensitive.
the said matrix being filled with this pH sensitive metal oxide. and an insulative layer which serves to mask a surface of the conductive layer between the said first terminal region and the said second region.
2. A pH sensors as claimed in Claim 1, wherein an alloy is formed comprising the material of the said metal and the material of the said conductive layer. which alloy forms a diffuse junction therebetween.
3. A pH sensor as claimed in Claim 1 or Claim 2, wherein the metal the oxide of which is pH sensitive is a metal in the transition series of the periodi table.
4. A pH sensor as claimed in any of Claims 1 to 3, wherein the conductix e layer comprises gold.
5. A pH sensor as claimed in any ot Claims 1 to 4. wherein the conductive layer comprises platintim.
6. A pH sensor as claimed in any preceding claim, wherein the conductive layer comprises a gold/platinum alloy.
7. A pH sensors as claimed in Claim 1. wherein the conductive layer comprises ruthenium oxide.
S. A pH sensor as claimed in Claim 1 . wherein the conductive layer comprises carbon.
9. A pH sensor as claimed in any ot Claims 3 to S. wherein the transition metal is iridium. the matrix being filled with iridium oxide.
1 0. A pH sensor as claimed in any preceding claim. wherein the substrate is made of alumina.
11. A pH sensors as claimed in any preceding claim. wherein the matrix is an epoxy resin or other polymeric material.
1 2. A pH sensor as claimed in any preceding claim. wherein the insulative layer is an epoxy resin or cermet material.
1 3. A pH sensor as claimed in Claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.
14. Apparatus for liquid monitoring/sensing comprising a sensor as claimed in any preceding claim.
15. Water quality monitoring apparatus comprising a sensor as claimed in any of Claims 1 to 13.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP95106312A EP0685736A1 (en) | 1994-05-13 | 1995-04-27 | Improvements in or relating to pH-sensors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9409554A GB9409554D0 (en) | 1994-05-13 | 1994-05-13 | Improvements in or relating to sensors |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9410859D0 GB9410859D0 (en) | 1994-07-20 |
| GB2289541A true GB2289541A (en) | 1995-11-22 |
Family
ID=10755043
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9409554A Pending GB9409554D0 (en) | 1994-05-13 | 1994-05-13 | Improvements in or relating to sensors |
| GB9410859A Withdrawn GB2289541A (en) | 1994-05-13 | 1994-05-31 | pH sensor |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9409554A Pending GB9409554D0 (en) | 1994-05-13 | 1994-05-13 | Improvements in or relating to sensors |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB9409554D0 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1035411A1 (en) * | 1999-03-05 | 2000-09-13 | AVL Medical Instruments AG | Electrochemical sensor |
| WO2000067010A1 (en) * | 1999-05-04 | 2000-11-09 | University Of South Australia | pH PROBE |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0433261A1 (en) * | 1989-12-14 | 1991-06-19 | Monsanto Company | Solid state pH sensor |
| EP0498572A2 (en) * | 1991-02-04 | 1992-08-12 | Ciba Corning Diagnostics Corp. | Electrodes for potentiometric sensors |
| EP0574354A1 (en) * | 1992-06-09 | 1993-12-15 | AVL Medical Instruments AG | Body for forming at least one electrode and/or a sensor |
-
1994
- 1994-05-13 GB GB9409554A patent/GB9409554D0/en active Pending
- 1994-05-31 GB GB9410859A patent/GB2289541A/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0433261A1 (en) * | 1989-12-14 | 1991-06-19 | Monsanto Company | Solid state pH sensor |
| EP0498572A2 (en) * | 1991-02-04 | 1992-08-12 | Ciba Corning Diagnostics Corp. | Electrodes for potentiometric sensors |
| EP0574354A1 (en) * | 1992-06-09 | 1993-12-15 | AVL Medical Instruments AG | Body for forming at least one electrode and/or a sensor |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1035411A1 (en) * | 1999-03-05 | 2000-09-13 | AVL Medical Instruments AG | Electrochemical sensor |
| US6613205B1 (en) | 1999-03-05 | 2003-09-02 | F. Hoffmann-La Roche Ag | Electrochemical sensor |
| WO2000067010A1 (en) * | 1999-05-04 | 2000-11-09 | University Of South Australia | pH PROBE |
| US6860984B2 (en) | 1999-05-04 | 2005-03-01 | Gastro Holdings Pty Ltd | pH electrode and methods of preparing and using same |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9409554D0 (en) | 1994-07-06 |
| GB9410859D0 (en) | 1994-07-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |