GB1600378A - Ion selective electrodes and in methods of measuring the concentration of ions - Google Patents
Ion selective electrodes and in methods of measuring the concentration of ions Download PDFInfo
- Publication number
- GB1600378A GB1600378A GB1845277A GB1845277A GB1600378A GB 1600378 A GB1600378 A GB 1600378A GB 1845277 A GB1845277 A GB 1845277A GB 1845277 A GB1845277 A GB 1845277A GB 1600378 A GB1600378 A GB 1600378A
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- GB
- United Kingdom
- Prior art keywords
- electrode
- hydride
- ion
- concentration
- acid
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- 150000002500 ions Chemical class 0.000 title claims description 72
- 238000000034 method Methods 0.000 title claims description 20
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 38
- 239000000203 mixture Substances 0.000 claims description 34
- 150000004678 hydrides Chemical class 0.000 claims description 29
- 239000002253 acid Substances 0.000 claims description 28
- 150000003839 salts Chemical class 0.000 claims description 26
- 229910052763 palladium Inorganic materials 0.000 claims description 20
- 239000003792 electrolyte Substances 0.000 claims description 15
- 229910052739 hydrogen Inorganic materials 0.000 claims description 15
- 239000001257 hydrogen Substances 0.000 claims description 15
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 13
- 239000007788 liquid Substances 0.000 claims description 13
- -1 palladium hydride Chemical class 0.000 claims description 13
- 229910045601 alloy Inorganic materials 0.000 claims description 12
- 239000000956 alloy Substances 0.000 claims description 12
- 229910052751 metal Inorganic materials 0.000 claims description 12
- 239000002184 metal Substances 0.000 claims description 12
- 229910052987 metal hydride Inorganic materials 0.000 claims description 12
- 150000004681 metal hydrides Chemical class 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 11
- 229910052727 yttrium Inorganic materials 0.000 claims description 10
- 235000021355 Stearic acid Nutrition 0.000 claims description 7
- 239000011521 glass Substances 0.000 claims description 7
- 229910001092 metal group alloy Inorganic materials 0.000 claims description 7
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 claims description 7
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 claims description 7
- 239000008117 stearic acid Substances 0.000 claims description 7
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 claims description 7
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 5
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 5
- 229910052788 barium Inorganic materials 0.000 claims description 5
- 239000011575 calcium Substances 0.000 claims description 5
- 229910052749 magnesium Inorganic materials 0.000 claims description 5
- 239000011777 magnesium Substances 0.000 claims description 5
- 229910052712 strontium Inorganic materials 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 239000010936 titanium Substances 0.000 claims description 5
- 229910052720 vanadium Inorganic materials 0.000 claims description 5
- 229910052726 zirconium Inorganic materials 0.000 claims description 5
- 229910052791 calcium Inorganic materials 0.000 claims description 4
- 238000011088 calibration curve Methods 0.000 claims description 4
- 235000014113 dietary fatty acids Nutrition 0.000 claims description 4
- 239000000194 fatty acid Substances 0.000 claims description 4
- 229930195729 fatty acid Natural products 0.000 claims description 4
- 150000004665 fatty acids Chemical class 0.000 claims description 4
- 239000011833 salt mixture Substances 0.000 claims description 4
- 229940075397 calomel Drugs 0.000 claims description 3
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical compound Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 claims description 3
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 claims description 3
- 229910052746 lanthanum Inorganic materials 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- 239000004677 Nylon Substances 0.000 claims description 2
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 2
- 230000000694 effects Effects 0.000 claims description 2
- 230000005518 electrochemistry Effects 0.000 claims description 2
- CZMAIROVPAYCMU-UHFFFAOYSA-N lanthanum(3+) Chemical compound [La+3] CZMAIROVPAYCMU-UHFFFAOYSA-N 0.000 claims description 2
- 238000005259 measurement Methods 0.000 claims description 2
- 229920001778 nylon Polymers 0.000 claims description 2
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 claims description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims 2
- XOOUIPVCVHRTMJ-UHFFFAOYSA-L zinc stearate Chemical class [Zn+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O XOOUIPVCVHRTMJ-UHFFFAOYSA-L 0.000 claims 1
- 239000000243 solution Substances 0.000 description 15
- 150000002739 metals Chemical class 0.000 description 4
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 3
- 229910001424 calcium ion Inorganic materials 0.000 description 3
- 238000011065 in-situ storage Methods 0.000 description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 3
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 3
- CJZGTCYPCWQAJB-UHFFFAOYSA-L calcium stearate Chemical compound [Ca+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CJZGTCYPCWQAJB-UHFFFAOYSA-L 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- HQKMJHAJHXVSDF-UHFFFAOYSA-L magnesium stearate Chemical compound [Mg+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O HQKMJHAJHXVSDF-UHFFFAOYSA-L 0.000 description 2
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- 229910001252 Pd alloy Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000008116 calcium stearate Substances 0.000 description 1
- 235000013539 calcium stearate Nutrition 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
- 235000019359 magnesium stearate Nutrition 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 239000002904 solvent Substances 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
- G01N27/38—Cleaning of electrodes
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 Electric Means (AREA)
Description
(54) IMPROVEMENTS IN ION SELECTIVE ELECTRODES AND
IN METHODS OF MEASURING THE CONCENTRATION OF IONS
(71) We, NATIONAL RESEARCH
DEVELOPMENT CORPORATION, a
British Corporation established by Statute, of Kingsgate House, 66 - 74 Victoria Street,
London, S.W.1, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
The present invention relates to ion selective electrodes which include a metal or metal alloy capable of forming a hydride, particularly but not exclusively palladium hydride. Such electrodes are used only when they also contain hydrogen and a hydride is present.
The present invention is a modification of, and in some respects an improvement in, the invention described in Specification No.
1,481,509 (Application No. 34132/73 - Inventor: John Vincent Dobson).
The absorption of considerable quantities of hydrogen in palladium and some other metals to form alloys known as hydrides is well known. Palladium hydride retains hydrogen for a considerable time at room temperature: for example an a + ss palladium hydride electrode will remain in this phase for many days.
Provided the electrode is in the (a + (3) phase, a palladium hydride electrode can be used to measure hydrogen ion concentration in aqueous solution in the same way as a conventional platinum-hydrogen electrode or a glass electrode.
In this specification, the term ion selective electrode means an electrode whose potential in a solution measured relative to a reference potential, depends on the concentration of a particular ion, or a particular group of ions, in the solution. Also in this specification. the term "hydride" means a combination of hydrogen with a metal, the combination often being regarded as an alloy, in which hydrogen is apparently "absorbed" by the metal instead of forming a stoichiometric compound.
According to a first aspect of the present invention there is provided an ion selective electrode for use in measuring the concentration of an ion in a predetermined liquid or in any one of a number of predetermined liquids, comprising a material capable of forming a hydride, the material being a metal or a metal alloy and the hydride being as hereinbefore defined, and a mixture of an acid and the salt of the acid with the ion, the concentration of which is to be measured, the acid and the salt being substantially insoluble in the predetermined liquid or in the predetermined liquids and the mixture being positioned in proximity with, but not in contact with, the material.
The present invention stems from the realisation that it is not necessary to the operation of the electrode that the said mixture is in contact with the hydride.
The metal is preferably palladium, but other metals which can be used include yttrium, zirconium, titanium, vanadium, or alloys of palladium with one or more of these metals, or alloys of two or more of these metals. In operation the metal or alloy is either precharged with hydrogen or charged with hydrogen in situ in, for example, one of the ways described in the above mentioned Specification No. 1,481,509.
Concentrations of the following ions: Ca,
Mg, Sr, Ba, Y and La may, for example, be measured if, of course, a different electrode is provided for each ion. Each such electrode includes a mixture of stearic acid and the salt of that acid with the ion, the concentration of which is to be measured, the mixture being in close proximity with the palladium.
Advantageously the acid and salt chosen for the mixture should have a melting point such that the mixture remains solid at the highest temperature at which the electrode can be used in view of increase in loss of hydrogen at high temperatures.
According to a second aspect of the present invention there is provided a method of measuring the concentration of an ion in a solution using an ion selective electrode which comprises a metal hydride as hereinbefore defined, or a metal alloy hydride as hereinbefore defined and a mixture of an acid and a salt of the acid with the ion the concentration of which is to be measured, the mixture being positioned in proximity with, but not in contact with, the metal hydride or the alloy hydride, and the acid and the salt being substantially insoluble in the solution, the method comprising the steps of contacting the solution with both the mixture and the metal hydride or the alloy hydride, at the same time contacting the solution with a reference electrode, and measuring the potential between the ion selective electrode and a reference electrode while both electrodes are in contact with the solution.
Claims to metal hydride electrodes which include a mixture of an insoluble acid and its salt as a coating for the electrode form part of the above mentioned Specification No.
1,481,509 and of Specification No.
1,481,510 (Appliction No. 743/77).
Certain embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure I is a schematic diagram of apparatus according to the invention, and
Figure 2 is a partial cross-section of another embodiment of apparatus according to the invention.
In Figure 1 a solution 10 containing calcium ions, the concentration of which is to be measured, is held by a beaker 11. A pallerium hydride electrode 12 is formed from a piece of palladium wire containing a coiled portion 13. The palladium wire may be precharged with hydrogen or may be charged in situ by using one of the methods described in Specification No. 1,481,509.
Terminals 14 are provided for the palladium wire so that its resistance can be monitored and charging with hydrogen, for example by electrolysis, may be carried out when the resistance of the wire indicates that the hydrogen content is low. A digital voltmeter (DVM) 15 is connected to the palladium hydride electrode 12 and to a reference electrode 16 shown schematically which may be of any appropriate known type such as a calomel electrode. The bottom of the beaker 11 contains a mixture of 50% stearic acid and 50% calcium stearate in the form of granules adjacent to the coil of palladium wire 13.
The concentration of calcium ions in the solution 10 is measured by observing the voltage difference between the palladium hydride electrode and the reference electrode 16. After the solution has been placed in the beaker, some time will be required before the voltage reading obtained from the DVM 15 settles down and in order to reduce this time a magnetic stirrer (not shown) may be placed in the beaker with its drive unit underneath. Solubility equilibrium is then achieved relatively quickly between stearic salts, the solvent and the ions to be measured. The voltage readings obtained from the DVM are compared with a calibration curve for the system previously prepared by plotting voltage against calcium ion concentration for known concentrations.
The arrangement of Figure 1 can only be used where pH is known and constant since, as is mentioned below, the palladium hydride electrode measures proton concentration resulting from an equilibrium set up between ions of the mixture and the ion whose concentration is to be measured.
Therefore the "background" concentration of proton in the electrolyte must be taken into account when the voltage measurements are taken and this is achieved by using a calibration curve for the appropriate pH value.
In Figure 2 a palladium wire 20 passes through a screwed plug 21 into the interior of a hollow PTFE former 22 with a threaded end portion 23. The wire 20 emerges from the interior of the former and passes round the threaded portion as shown. Granules of 50% stearic acid and 50% magnesium stearate mixture 24 are contained in a chamber formed by cylindrical grids 25 and 26 surrounding the threaded portion of the former 22. The grid structure can be formed from any rigid non-conducting material such as
PTFE and may be a push-fit on the PTFE former 22 so that several different grid structures containing different acid/salt mixtures may be mounted on a former at different times giving an electrode sensitive to various ions.
The grid structure is designed to allow solubility equilibrium of the various ions to be achieved in the space between the grid 25 and the portion 23 of the former 22 without unduly restricting the flow of electrolyte through the grid which would result in the liquid in the space being unrepresentative of the electrolyte around the outer grid 26.
The concentration of magnesium ions may be measured by dipping the probe of
Figure 2 into an electrolyte containing the ions and measuring the voltage difference between the palladium wire 20 and a reference electrode also inserted in the electrolyte. As before the palladium wire is either precharged with hydrogen or charged in situ and for the latter purpose the resistance between the two ends of the wire 20 may be monitored to provide an indication of the concentration of hydrogen in the wire.
The arrangement of Figure 2 can be used where the electrolyte has a constant known pH, when the reference electrode may again be a calomel electrode and an appropriate calibration curve is used. Alternatively the pH of the electrolyte may vary and it is then necessary to use a pH sensitive electrode as the reference electrode. For example the reference electrode may be a glass electrode or preferably one of the palladium hydride electrodes described in the above mentioned Specification No. 1,481,509. Variations in the pH of the electrolyte are then automatically taken into account by what is, in effect, a differential system.
In preparing other electrodes similar to those of Figures 1 and 2, the acid/salt mixture may be heated until melted and then poured into a flexible porous container such as a nylon gauze, linen or even paper.
The flexible container is held in a desired shape until the mixture has become solid when the mixture plus container can be removed and positioned either in close proximity to the coil 13 or palladium wire or around the end portion of the former 22 but spaced therefrom.
The ion selective electrodes of Figures 1 and 2 can. of course, be made sensitive to other ions simply by using other stearates, having the appropriate ion instead of calcium or magnesium in the mixture. Indeed these electrodes can be made responsive to strontium, barium. yttrium and lanthium in aqueous electrolytes if the palladium wire is used in close proximity with a fatty acid and its salt of the ion whose concentration is required.
The operation of ion selective electrodes based on glass electrodes is described in a paper by Attar and Beck entitled "Alkaline
Earth and Lanthanum Ion Electrodes of the
Third Kind based on the Hydrogen Ion
Responsive Glass Electrode". published in the Journal of Electro-Analytical Chemistry and Interfacial Electrochemistry, 27 (1970) pages 59 to 67. It is thought that the palladium hydride electrode when used in close proximity with one of the above mentioned mixtures operates in a way which is analogous to the ion selective electrodes of the paper.
Briefly the electrodes are believed to operate as follows. An equilibrium is set up between the ions to be measured and ions formed when the fatty acid and salt ionise.
The resulting concentration of proton depends on the concentration of the ion of interest and using the palladium hydride electrode to measure proton concentration indirectly measures the required concentration.
Although two specific forms of the invention have been described it will be appreciated that many other forms of the invention are possible, the only essentials being that the hydride and the mixture of an acid and its salt are near to one another.
WHAT WE CLAIM IS:
1. An ion selective electrode for use in measuring the concentration of an ion in a predetermined liquid or in any one of a number of predetermined liquids, comprising a material capable of forming a hydride, the material being a metal or a metal alloy and the hydride being as hereinbefore defined, and a mixture of an acid and the salt of the acid with the ion, the concentration of which is to be measured, the acid and the salt being substantially insoluble in the predetermined liquid or in the predetermined liquids and the mixture being positioned in proximity with, but not in contact with, the material.
2. A method of measuring the concentration of an ion in a solution using an ion selective electrode which comprises a metal hydride as hereinbefore defined, or a metal alloy hydride as hereinbefore defined and a mixture of an acid and a salt of the acid with the ion the concentration of which is to be measured, the mixture being positioned in proximity with, but not in contact with, the metal hydride or the alloy hydride, and the acid and the salt being substantially insoluble in the solution, the method comprising the steps of contacting the solution with both the mixture and the metal hydride or the alloy hydride, at the same time contacting the solution with a reference electrode, and measuring the potential between the ion selective electrode and a reference electrode while both electrodes are in contact with the solution.
3. An ion selective electrode or a method according to Claim 1 or 2 wherein the hydride is a metal hydride comprising palladium, or yttrium, or zirconium, or titanium, or vanadium.
4. An ion selective electrode or a method according to Claim 1 or 2 wherein the hydride is an alloy hydride comprising at least two of the following: palladium, yttrium, zirconium, titanium and vanadium.
5. An ion selective electrode or a method according to any preceding claim wherein the acid is a stearic acid.
6. An ion selective electrode or a method according to Claim 5 wherein the salt is a salt of a stearic acid with one of the following ions: Ca, Mg, Sr, Ba, Y and La.
7. An ion selective electrode according to Claim 1 or any of Claims 2 to 6 wherein the said material is in the form of a wire.
8. An ion selective electrode according to Claim 7 comprising an insulating former
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (12)
1. An ion selective electrode for use in measuring the concentration of an ion in a predetermined liquid or in any one of a number of predetermined liquids, comprising a material capable of forming a hydride, the material being a metal or a metal alloy and the hydride being as hereinbefore defined, and a mixture of an acid and the salt of the acid with the ion, the concentration of which is to be measured, the acid and the salt being substantially insoluble in the predetermined liquid or in the predetermined liquids and the mixture being positioned in proximity with, but not in contact with, the material.
2. A method of measuring the concentration of an ion in a solution using an ion selective electrode which comprises a metal hydride as hereinbefore defined, or a metal alloy hydride as hereinbefore defined and a mixture of an acid and a salt of the acid with the ion the concentration of which is to be measured, the mixture being positioned in proximity with, but not in contact with, the metal hydride or the alloy hydride, and the acid and the salt being substantially insoluble in the solution, the method comprising the steps of contacting the solution with both the mixture and the metal hydride or the alloy hydride, at the same time contacting the solution with a reference electrode, and measuring the potential between the ion selective electrode and a reference electrode while both electrodes are in contact with the solution.
3. An ion selective electrode or a method according to Claim 1 or 2 wherein the hydride is a metal hydride comprising palladium, or yttrium, or zirconium, or titanium, or vanadium.
4. An ion selective electrode or a method according to Claim 1 or 2 wherein the hydride is an alloy hydride comprising at least two of the following: palladium, yttrium, zirconium, titanium and vanadium.
5. An ion selective electrode or a method according to any preceding claim wherein the acid is a stearic acid.
6. An ion selective electrode or a method according to Claim 5 wherein the salt is a salt of a stearic acid with one of the following ions: Ca, Mg, Sr, Ba, Y and La.
7. An ion selective electrode according to Claim 1 or any of Claims 2 to 6 wherein the said material is in the form of a wire.
8. An ion selective electrode according to Claim 7 comprising an insulating former
on which the wire is wound, a chamber containing the acid-salt mixture, the chamber having apertured walls and surrounding the former where it carries the wire, and an enclosed space between the former and those walls of the chamber which face the former, access for electrolyte to the space being only by way of the chamber when the chamber is immersed in an electrolyte.
9. A method according to Claim 2 or any of Claims 3 to 6 for measurement in a solution of varying pH, wherein the reference electrode used is a pH sensitive electrode.
10. An ion selective electrode substantially as hereinbefore described with reference to, and as shown in, Figure 1 of the accompanying drawings.
11. An ion selective electrode substantially as hereinbefore described with reference to, and as shown in, Figure 2 of the accompanying drawings.
12. A method of measuring the concentration of an ion in a solution substantially as hereinbefore described.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1845277A GB1600378A (en) | 1977-05-03 | 1977-05-03 | Ion selective electrodes and in methods of measuring the concentration of ions |
| US05/811,845 US4152235A (en) | 1973-07-18 | 1977-06-30 | Ion selective electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1845277A GB1600378A (en) | 1977-05-03 | 1977-05-03 | Ion selective electrodes and in methods of measuring the concentration of ions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1600378A true GB1600378A (en) | 1981-10-14 |
Family
ID=10112686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1845277A Expired GB1600378A (en) | 1973-07-18 | 1977-05-03 | Ion selective electrodes and in methods of measuring the concentration of ions |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1600378A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104155476A (en) * | 2014-06-16 | 2014-11-19 | 厦门乐钢材料科技有限公司 | Compound microprobe for in-situ measurement of STM image and chloride ion concentration distribution and preparation method thereof |
-
1977
- 1977-05-03 GB GB1845277A patent/GB1600378A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104155476A (en) * | 2014-06-16 | 2014-11-19 | 厦门乐钢材料科技有限公司 | Compound microprobe for in-situ measurement of STM image and chloride ion concentration distribution and preparation method thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |