DE1917179A1 - Standard cell for partial oxygen pressure - determination - Google Patents
Standard cell for partial oxygen pressure - determinationInfo
- Publication number
- DE1917179A1 DE1917179A1 DE19691917179 DE1917179A DE1917179A1 DE 1917179 A1 DE1917179 A1 DE 1917179A1 DE 19691917179 DE19691917179 DE 19691917179 DE 1917179 A DE1917179 A DE 1917179A DE 1917179 A1 DE1917179 A1 DE 1917179A1
- Authority
- DE
- Germany
- Prior art keywords
- measuring cell
- cathode
- electrolyte
- silver ions
- cell according
- 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.)
- Granted
Links
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims description 8
- 239000001301 oxygen Substances 0.000 title claims description 8
- 229910052760 oxygen Inorganic materials 0.000 title claims description 8
- 230000036961 partial effect Effects 0.000 title claims description 4
- 239000003792 electrolyte Substances 0.000 claims abstract description 12
- 229910052709 silver Inorganic materials 0.000 claims abstract description 10
- 239000004332 silver Substances 0.000 claims abstract description 10
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims abstract description 6
- 229910021607 Silver chloride Inorganic materials 0.000 claims abstract description 5
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 claims abstract description 5
- 150000003839 salts Chemical class 0.000 claims abstract description 4
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims abstract description 3
- 235000017557 sodium bicarbonate Nutrition 0.000 claims abstract description 3
- 239000007787 solid Substances 0.000 claims abstract description 3
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims abstract 6
- 229910000027 potassium carbonate Inorganic materials 0.000 claims abstract 3
- 239000012528 membrane Substances 0.000 claims description 8
- 239000007789 gas Substances 0.000 claims description 7
- -1 KBr Chemical compound 0.000 claims description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 4
- 239000001257 hydrogen Substances 0.000 claims description 4
- 229910052739 hydrogen Inorganic materials 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 239000000872 buffer Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims description 2
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 claims 4
- 239000000243 solution Substances 0.000 claims 3
- 239000002253 acid Substances 0.000 claims 2
- 150000007513 acids Chemical class 0.000 claims 2
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 claims 1
- 239000000654 additive Substances 0.000 claims 1
- 230000000996 additive effect Effects 0.000 claims 1
- 235000013405 beer Nutrition 0.000 claims 1
- 239000007853 buffer solution Substances 0.000 claims 1
- 150000001875 compounds Chemical class 0.000 claims 1
- 229910010272 inorganic material Inorganic materials 0.000 claims 1
- 239000011147 inorganic material Substances 0.000 claims 1
- 239000011368 organic material Substances 0.000 claims 1
- 239000011148 porous material Substances 0.000 claims 1
- 230000001603 reducing effect Effects 0.000 claims 1
- 238000000926 separation method Methods 0.000 claims 1
- 235000015040 sparkling wine Nutrition 0.000 claims 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 abstract description 4
- 239000010425 asbestos Substances 0.000 abstract description 2
- 230000001627 detrimental effect Effects 0.000 abstract description 2
- 239000011491 glass wool Substances 0.000 abstract description 2
- 229910052895 riebeckite Inorganic materials 0.000 abstract description 2
- 230000000694 effects Effects 0.000 abstract 1
- 239000000945 filler Substances 0.000 abstract 1
- ILVUABTVETXVMV-UHFFFAOYSA-N hydron;bromide;iodide Chemical compound Br.I ILVUABTVETXVMV-UHFFFAOYSA-N 0.000 abstract 1
- 150000002500 ions Chemical class 0.000 abstract 1
- 239000002244 precipitate Substances 0.000 abstract 1
- 239000010931 gold Substances 0.000 description 8
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 6
- 229910052737 gold Inorganic materials 0.000 description 6
- 238000005259 measurement Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229940100890 silver compound Drugs 0.000 description 2
- 150000003379 silver compounds Chemical class 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 241001101998 Galium Species 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 150000003842 bromide salts Chemical class 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229920001821 foam rubber Polymers 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 150000004694 iodide salts Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 210000004072 lung Anatomy 0.000 description 1
- 230000028161 membrane depolarization Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000011490 mineral wool Substances 0.000 description 1
- 239000012766 organic filler Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
- 230000036962 time dependent Effects 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
- G01N27/403—Cells and electrode assemblies
- G01N27/404—Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid, e.g. Clark-type oxygen sensors
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 Analysing Biological Materials (AREA)
- Measuring Oxygen Concentration In Cells (AREA)
Abstract
Description
CO2-resistente Oxi-Messelektrode 3 e 5 c h r e i.b u n g Die Erfindung betrifft eine Meßelektrode zur Bestimmung von Sauerstoff in Flüssigkeiten und Gasen. Diese Meßzelle besteht aus einem Meßkopf, in dem sich eine Kathode und Anode in einem neuartigen C02-resistenten Elektrolyten befinden. CO2-resistant Oxi measuring electrode 3 e 5 c h r e i.b u n g The invention relates to a measuring electrode for the determination of oxygen in liquids and gases. This measuring cell consists of a measuring head in which a cathode and anode are in a new type of C02-resistant electrolyte.
Der Meßkopf wird nach außen von einer gaspermeablen, flach über die Kathode gespannten Membran abgeschlossen.The measuring head is exposed to the outside by a gas-permeable, flat over the Cathode-tensioned membrane completed.
Die Bestimmung von Sauerstoff mit den bekannten Meßzellen nach Clark und Grasshoff erfolgt durch Anlegen einer konstanten Spannung an ein Elektrodensystem von Gold bzw. Platin als Kathode und Silber als Anode, so daß eine Polarisation eintritt unter Beladung der Goldkathode mit rasserstoff.The determination of oxygen with the known measuring cells according to Clark and Grasshoff is done by applying a constant voltage to an electrode system of gold or platinum as cathode and silver as anode, so that a polarization Entrance with loading of the gold cathode with hydrogen.
Der durch die Membran, zur Goldkathode diffundierende Sauerstoff depolarisiert die Wasserstoffbeladung und ruft einen Depolarisationsstrom hervor, dessen Größe eine Funktion vom Partialdruck des Sauerstoffs in der Umgebung der Meßzelle ist.The oxygen diffusing through the membrane to the gold cathode depolarizes the hydrogen charge and causes a depolarization current, its size is a function of the partial pressure of the oxygen in the vicinity of the measuring cell.
Der Vorgang läßt sich durch die folgende Reaktionsgleichung darstellen.
Dieser Aufbau, sowie die Zusammensetzung des Elektrolyt-Gels hat im Betrieb erhebliche mängel, die sich in einer stark begrenzten Lebensdauer, geringer Beßsicherheit und durch häufid Notwendigkeit zur Kalibration zeigen. Diese Mängel treten bei Anwesenheit von C02 noch besonders stark hervor. Die bisherige Art der Meßzelle ist daher für Sauerstoffmessungen in C02-haltiger Atmosphäre und -Lösung unbrauchbar.This structure, as well as the composition of the electrolyte gel, has im Operation significant defects, which result in a very limited service life, less Show certainty of biting and frequent need for calibration. These shortcomings are particularly pronounced in the presence of CO2. The previous type of The measuring cell is therefore used for oxygen measurements in atmospheres and solutions containing CO2 unusable.
Die Ursachen für diese Mängel liegen in der Tatsache, daß beim Betrieb der Meßzelle das sich an der Anode bildende Silberchlorid eine zu große Löslichkeit besitzt und daher im angelegten Potentialgefälle Silberionen zur Kathode wandern und auf dieser als metallisches Silber abgeschieden werden.The causes of these defects lie in the fact that during operation of the measuring cell, the silver chloride forming at the anode has too great a solubility and therefore silver ions migrate to the cathode in the applied potential gradient and deposited thereon as metallic silver.
Dadurch wird die Meßzelle inaktiv. Darüber hinaus bewirkt das durch die Membran an die Kathode diffundierende C02 in kurzer Zeit eine starke pH-Anderung im Kathodenraum und damit eine hinderung der Wasserstoffbeladung an der Goldkathode um mehrere Zehnerpotenzen der Beladungsdichte, wodurch die Empfindlichkeit verändert wird und damit die Meßwerte verfälscht werden.This makes the measuring cell inactive. In addition, this causes through C02 diffusing the membrane to the cathode causes a strong pH change in a short time in the cathode compartment and thus an inhibition of the hydrogen loading on the gold cathode by several powers of ten of the loading density, which changes the sensitivity and thus the measured values are falsified.
Die Abdichtung der Meßzelle durch eine Membran mittels eines O-Ringes verursacht diene sternförmige Faltung der Membran, die dadurch Bruchstellen erhält, welche im Laufe der Zeit zu Undichtigkeiten führen. Durch diese Undichtigkeiten kann das Elektrolyt-Gel aus der Meßzelle heraustreten, Fremdstoff ein dringen und somit meßtechnisch Störeffekte hervorrufen.The measuring cell is sealed by a membrane using an O-ring causes the star-shaped folding of the membrane, which thereby becomes rupture points, which lead to leaks over time. Because of these leaks the electrolyte gel can emerge from the measuring cell, foreign matter can penetrate and thus cause metrological interfering effects.
Diese Naohteile zu beseitigen hat sich vorliegende Erfindung zur Aufgabe gestellt.The object of the present invention is to eliminate these sewage parts posed.
Erfindungsgemäß werden die genannten Nachteile der bisherigen Meßzellen für den Partialdruck von Sauerstoff dadurch beseitigt, daß dem Elektrolyt ein Salz zugegeben wird, welrohes mit den Silberionen eine schwerer lösliche Silberverbindung als Silberchlorid bildet. Als Beispiele kommen Bromide, Jodid, Alkalisulfide etc. in Frage. Diese Silberverbindungen sollen im Anodenraum ausfallen. Damit diese Ft1-lungen weiterhin im Anodenraum verbleiben, wird durch Feststoffüllungen, die dem Elektrolyt beigegeben werden, garantiert. Als Füllmaterialien eignen sich alle inaktiven organischen und anorganischen saugfähigen Materialien, wie z.B., Asbest, Watte, Kieselgur, Glaswolle, Steinwolle, Tonerden und poröse Kunststoffe, Schaumgummi etc.. Zur Ausschaltung des schädlichen Einflusses des C02-Gases wird der Elektrolyt außerdem dahingehend abgeändert, daß er zusätzlich aus einer mögliohst hohen Konzentration von leicht löslichem galiumkarbonat und Natriumbikarbonat im optimalen Mischungsverhältnis besteht. Dieses Gemisch stellt einen Puffer dar, der während des Arbeitens der Elektrode in C02-haltigen Gasen und -Lösungen die Wasserstoffionen-Konzentration im Kathodenraum hinreichend konstant hält. Damit werden zeitabhängige Meßergebnisse vermieden und die Arbeitsfähigkeit der Elektrode bleibt erhalten.According to the invention, the mentioned disadvantages of the previous measuring cells for the partial pressure of oxygen eliminated by adding a salt to the electrolyte added, which is a poorly soluble silver compound with the silver ions forms as silver chloride. Examples include bromides, iodides, alkali sulfides, etc. in question. These silver compounds should fail in the anode compartment. So that these Ft1 lungs continue to remain in the anode compartment, is caused by solid fillings that form the electrolyte added, guaranteed. All inactive organic fillers are suitable and inorganic absorbent materials such as asbestos, wadding, diatomite, glass wool, Rock wool, clays and porous plastics, foam rubber etc .. To switch off The electrolyte also becomes detrimental to the harmful influence of the CO 2 gas modified so that he also made a concentration of light as high as possible soluble galium carbonate and sodium bicarbonate in the optimal mixing ratio consists. This mixture acts as a buffer for the electrode in gases and solutions containing CO2, the hydrogen ion concentration in the cathode compartment keeps sufficiently constant. Time-dependent measurement results are thus avoided and the working capacity of the electrode is retained.
Die weitere vorteilhafte Ausgestaltung der Meßzelle besteht darin, daß die Iezbranfolie (4) (gemäß beigegebener Prinzipskizze der CO2 resistentan OtI-Yeßzelle) plan- und faltenfrei, sowie enganliegend über die Kathode (6) gespannt wird. Zusätzlich wird die Xembranfolie (4) rund um die Kathode (6) durch eine Dichtungascheibe (3) mittels einer kleinen Andruckplatte (2) abgedichtet. Dadurch wird die Xeibran-Folie (4) vor Versetzungen geschützt, bleibt damit dicht und verhindert das Austreten von Elektrolyt, sowie das Eindringen von schädlichen Gasen und Freiditoffen in den Klektrolytvorratsraum (7).Another advantageous embodiment of the measuring cell is that the Iezbran film (4) (according to the attached schematic diagram of the CO2 resistant OtI-Yeß cell) is stretched flat and wrinkle-free, as well as tightly over the cathode (6). Additionally the membrane film (4) around the cathode (6) is secured by a sealing washer (3) sealed by means of a small pressure plate (2). This creates the Xeibran film (4) Protected from dislocation, thus remains tight and prevents leakage of electrolyte, as well as the penetration of harmful gases and non-polluting substances into the Klektrolyte storage space (7).
Aufgrund dieser Anordnung wird die Lebensdauer und Yeßsicherheit entscheidend erhöht und die Messung von 02 in C02-haltigen Gasen und Ldaungen erst ermöglicht.Due to this arrangement, the service life and reliability are crucial increased and the measurement of 02 in C02-containing gases and Ldaungen made possible in the first place.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19691917179 DE1917179C3 (en) | 1969-04-03 | Measuring cell for determining the oxygen partial pressure in acids or gases that form bases, such as CO deep 2, NH deep 3, or in solutions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19691917179 DE1917179C3 (en) | 1969-04-03 | Measuring cell for determining the oxygen partial pressure in acids or gases that form bases, such as CO deep 2, NH deep 3, or in solutions |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| DE1917179A1 true DE1917179A1 (en) | 1970-10-08 |
| DE1917179B2 DE1917179B2 (en) | 1975-07-10 |
| DE1917179C3 DE1917179C3 (en) | 1976-02-26 |
Family
ID=
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4058447A (en) * | 1975-02-13 | 1977-11-15 | Radiometer A/S | Electrochemical measuring electrode |
| US4187162A (en) * | 1978-06-26 | 1980-02-05 | Rosemount Inc. | Electrochemical cell |
| EP0252263A3 (en) * | 1986-06-06 | 1989-08-23 | Kontron-Holding Ag | Electrodes arrangement |
| EP0248304A3 (en) * | 1986-06-06 | 1989-08-23 | Kontron Instruments Holding N.V. | Electrodes arrangement |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4058447A (en) * | 1975-02-13 | 1977-11-15 | Radiometer A/S | Electrochemical measuring electrode |
| US4187162A (en) * | 1978-06-26 | 1980-02-05 | Rosemount Inc. | Electrochemical cell |
| EP0252263A3 (en) * | 1986-06-06 | 1989-08-23 | Kontron-Holding Ag | Electrodes arrangement |
| EP0248304A3 (en) * | 1986-06-06 | 1989-08-23 | Kontron Instruments Holding N.V. | Electrodes arrangement |
Also Published As
| Publication number | Publication date |
|---|---|
| DE1917179B2 (en) | 1975-07-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C3 | Grant after two publication steps (3rd publication) | ||
| E77 | Valid patent as to the heymanns-index 1977 | ||
| EHJ | Ceased/non-payment of the annual fee |