DE629280C - Glass electrode for measuring the acidity level - Google Patents
Glass electrode for measuring the acidity levelInfo
- Publication number
- DE629280C DE629280C DEK134475D DEK0134475D DE629280C DE 629280 C DE629280 C DE 629280C DE K134475 D DEK134475 D DE K134475D DE K0134475 D DEK0134475 D DE K0134475D DE 629280 C DE629280 C DE 629280C
- Authority
- DE
- Germany
- Prior art keywords
- glass
- measuring
- glass electrode
- membrane
- acidity level
- 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.)
- Expired
Links
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
- G01N27/36—Glass 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
Glaselektrode zur Messung des Säuregrades Glaselektroden zur PH-Messung sind in der Form bekannt, daß eine dünne plättchen-oder kugelförmige Glasmembran an ein Glasrohr angeschmolzen ist, wie es die Abb-. i der Zeichnung zeigt.Glass electrode for measuring acidity Glass electrodes for measuring pH are known in the form of a thin plate-shaped or spherical glass membrane is fused to a glass tube, as shown in the Fig-. i of the drawing shows.
Das durch die Membran abgeschlossene gläserne Tauchrohr wird teilweise mit einer Bezugsflüssigkeit bekannten PH-Wertes gefüllt und in die zu messende Lösung eingetaucht. Die Glasmembran übt infolge der in ihr enthaltenen freien Wasserstoffionen die Funktion einer Wasserstoffelektrode aus, so daß die beiden angrenzenden Lösungen ein von ihrer Wasserstoffionenkonzentration abhängiges Potential gegenüber der Membran annehmen. Die Potentiale der beiden Lösungen werden durch in dieselben eintauchende konstante Bezugselektroden abgeleitet. Die Potentialdifferenz, welche nach einem stromlosen Spannungsmeßverfahren bestimmt wird, ist dann ein Maß für den Unterschied des pH-Wertes der Meßlösung gegenüber der Bezugslösung.The glass immersion tube closed off by the membrane is partially filled with a reference liquid with a known pH value and added to the solution to be measured immersed. The glass membrane exercises as a result of the free hydrogen ions it contains the function of a hydrogen electrode, so that the two adjacent solutions a potential relative to the membrane that depends on its hydrogen ion concentration accept. The potentials of the two solutions are immersed in the same constant reference electrodes derived. The potential difference, which after a electroless voltage measurement method is determined, is then a measure of the difference the pH value of the measurement solution compared to the reference solution.
Bei der beschriebenen Form der Elektrode bereitet die leichte Zerbrechlichkeit der Membran große Schwierigkeiten, da dieselbe hauchdünn sein muß; ferner ist vor allem die notwendige erhebliche Länge des Glasrohres störend, welche erforderlich ist, um Kriechströme von der einen zur andern durch die Membran getrennten,Lösung zu verhindern. Da zwecks Erzielung eines genauen Meßergebnisses ein Strom nur durch die Glasmembran, welche viele Megohm Widerstand hat, gehen darf, muß der Isolationswiderstand der Wandungen des Glasrohres für Kriechströme mindestens einige hundert Megohm betragen.With the described shape of the electrode, it is easy to break the membrane great difficulties, since it must be extremely thin; further is before especially disturbing the necessary considerable length of the glass tube which is required is to avoid leakage currents from one to the other separated by the membrane, solution to prevent. Since in order to achieve an accurate measurement result, a current only through the glass membrane, which has many megohms resistance, must go, the insulation resistance must the walls of the glass tube for leakage currents amount to at least a few hundred megohms.
Man kann nun der Membran auch etwas stabilere Formen geben, z. B. die Gestalt eines längeren dünnwandigen Glasröhrchens, welches zu einer Spirale oder ähnlichen Gestalt gebogen ist und an ein weiteres längeres Rohr (ähnlich Abb. i) angeschmolzen ist. Solche Röhrchen lassen sich jedoch nicht im entferntesten mit einer so dünnen Wandstärke herstellen und biegen, wie sie die obengenannten hauchdünnen Membranen besitzen. Sie haben daher einen außergewöhnlich hohen elektrischen Widerstand. Bei ihrer Verwendung muß man das angesetzte Glasrohr aus den angeführten Gründen extrem lang machen.The membrane can now also be given a somewhat more stable shape, e.g. B. the shape of a longer, thin-walled glass tube, which forms a spiral or similar shape and attached to another longer tube (similar to Fig. i) has melted. Such tubes, however, cannot be remotely located Manufacture and bend with such a thin wall thickness as the above have wafer-thin membranes. They therefore have an exceptionally high electrical level Resistance. When using them, the attached glass tube must be taken from the ones listed Making grounds extremely long.
Gemäß der Erfindung lassen sich die genannten Nachteile dadurch vermeiden, daß man die Glasmembran mit einem Bernsteinrohr kombiniert. Es hat sich gezeigt, daß man dem Bernsteinrohr nur etwa l/lo derjenigen Länge zu geben. braucht, welche ein Glasrohr unter sonst gleichen Verhältnissen besitzen müßte. Der Grund dürfte darin liegen, daß am Glasrohr von den Lösungen her, in welche die Glaselektrode eintaucht, leitende Flüssigkeitshäutchen exnporkriechen, was beim !Bernstein nicht stattfindet.According to the invention, the disadvantages mentioned can be avoided by that one combines the glass membrane with an amber tube. It has shown, that one should give the amber tube only about 1/10 of that length. needs which would have to have a glass tube under otherwise identical conditions. The reason is likely lie in the fact that on the glass tube from the solutions in which the glass electrode immersed, conductive membranes of liquid exnporealcrawling, what with! amber not takes place.
Man kommt auf diese Weise durch die Erfindung zu handlichen, für Transport, Gebrauch und Aufbewahrung gut geeigneten. Glaselektroden. Eine Ausführungsform zeigt z. B. Abb. 2.In this way, the invention makes it easy to handle, for transport, Suitable for use and storage. Glass electrodes. One embodiment shows z. B. Fig. 2.
Das in Form einer flachen Spirale gewundene dünnwandige Glasrohr M, welches an einem Ende zugeschmolzen ist, erweitert sich am anderen Ende zu einem kräftigeren Teil normaler Wandstärke mit einem konisch geformten Ende. Dieses ist mit einem gut isolierenden Kitt (z. B. Schellack) in eine ebenfalls konische Ausbohrung eines röhrenförmigen Schaftes aus Bernstein eingekittet.The thin-walled glass tube M, wound in the form of a flat spiral, which is fused shut at one end expands to one at the other end thicker part of normal wall thickness with a conical end. This is with a well-insulating putty (e.g. shellac) in an equally conical bore a tubular shaft made of amber cemented.
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEK134475D DE629280C (en) | Glass electrode for measuring the acidity level |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEK134475D DE629280C (en) | Glass electrode for measuring the acidity level |
Publications (1)
Publication Number | Publication Date |
---|---|
DE629280C true DE629280C (en) | 1936-04-25 |
Family
ID=7248129
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DEK134475D Expired DE629280C (en) | Glass electrode for measuring the acidity level |
Country Status (1)
Country | Link |
---|---|
DE (1) | DE629280C (en) |
-
0
- DE DEK134475D patent/DE629280C/en not_active Expired
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