JP2004226263A - Electrolyte for diaphragm type electrode, the diaphragm type electrode, and method for stabilizing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolyte for diaphragm type electrodes that can allow electrodes to reach stable potential speedily, reduces aging time, and can be set to a measurable state quickly regardless of the storage state of the electrode, and to provide the diaphragm type electrode, and a method for stabilizing the diaphragm type electrode. <P>SOLUTION: A chamber 2a that is partitioned from the outside by a diaphragm 3 for penetrating gas to be measured in a sample is provided at one end of an electrode body 2, an operation electrode 4 and a counter electrode 7 are arranged in the chamber 2a with the electrodes 4 and 7 present in the electrolyte 6, the electrolyte 6 for the diaphragm type electrode used for the diaphragm type electrode for measuring current flowing between the operation electrode 4 and the counter electrode 7 by allowing the gas to be measured that is penetrated through the diaphragm 3 to react at the counter electrode 4 contains a metal ion of the same type as metal for composing the operation electrode 4 in the diaphragm type electrode 1, a metal complex, or a metal compound. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a diaphragm type used for a diaphragm type electrode for measuring the concentration of a target substance in a sample, that is, a gas to be measured which is an oxidant or a reductant, for example, dissolved oxygen or dissolved hydrogen in a solution or air. The present invention relates to an electrolytic solution for electrodes, and further to a diaphragm electrode and a method for stabilizing a diaphragm electrode.
[0002]
[Prior art]
For example, in the fields of environmental (river, seawater) water treatment, fermentation, and aquaculture, measurement of dissolved oxygen (oxidant) in a sample solution is important, and a dissolved oxygen meter is widely used for monitoring and process control. As a sensor of this dissolved oxygen meter, a diaphragm electrode using an oxygen permeable diaphragm, that is, a polarographic diaphragm electrode, a galvanic cell diaphragm electrode, or the like is mainly used. In nuclear power plants and the like, measurement of dissolved hydrogen (reduced substance) is important, and monitoring is performed by a meter.
[0003]
FIG. 2 shows a polarographic diaphragm-type electrode (hereinafter referred to as “polarographic electrode”) 1A using a conventional gas-permeable diaphragm. As shown in the figure, a polarographic electrode 1A has, for example, a gas permeable diaphragm 3 that allows a gas to be measured to permeate through a front end opening of a hollow cylindrical electrode main body 2, and the inside of the electrode main body close to the diaphragm 3 The working electrode 4 is disposed opposite to each other. The working electrode 4 is attached to the tip of a support tube 5 that is coaxially disposed inside the electrode body 2.
[0004]
The working electrode 4 is opposed to the diaphragm 3 with a slight gap. Therefore, a thin layer of the electrolytic solution 6 exists between the working electrode 4 and the diaphragm 3. A counter electrode 7 is attached to the outer periphery of the support tube 5. Then, a predetermined electrolytic voltage is continuously applied between the counter electrode 7 and the working electrode 4 from the power source 8 via the lead wires 7a and 4a connected thereto (usually, a negative voltage is applied to the working electrode 4). The dissolved gas concentration in the sample solution is obtained by measuring the steady value of the electrolysis current with an ammeter 9. As the working electrode 4, silver (Ag), platinum (Pt), and gold (Au) are generally used, and as the counter electrode 7, silver (Ag) and silver-silver chloride (Ag / AgCl) are used.
[0005]
For example, when measuring the concentration of dissolved oxygen in a sample solution, in the configuration shown in FIG. 2, platinum (Pt) is used as the working electrode 4, silver (Ag) is used as the counter electrode 7, and potassium chloride (KCl) solution is used as the electrolytic solution 6. When used, the current-voltage characteristics of the polarographic electrode 1A are as shown in FIG. That is, a steady electrolytic current of dissolved oxygen is obtained when the negative voltage applied to the working electrode 4 with respect to the counter electrode 7 is in the range of approximately -0.3V to -1.0V. Utilizing the fact that this electrolytic current is proportional to the dissolved oxygen partial pressure, the dissolved oxygen concentration is obtained from the measured electrolytic current value. The technology behind the polarographic electrode 1A to which the present invention can be applied is well known to those skilled in the art.
[0006]
FIG. 3 shows a galvanic cell type diaphragm electrode (hereinafter referred to as “galvanic cell type electrode”) 1B. Unlike the polarographic electrode 1A shown in FIG. 2, the galvanic cell type electrode 1B does not have a power source 8. That is, the galvanic cell type electrode 1B does not need to apply a voltage from the outside at the time of use. Generally, the working electrode 4 made of silver (Ag), platinum (Pt), gold (Au), etc., lead (Pb), A counter electrode 7 made of cadmium (Cd) or the like is used in combination. Then, by immersing both electrodes in the electrolytic solution 6 to form a circuit, the current flowing between the electrodes is measured. The technology behind the galvanic cell type electrode 1B to which the present invention can be applied is well known to those skilled in the art.
[0007]
[Patent Document 1]
Japanese Patent Publication No. 43-2833 [0008]
[Problems to be solved by the invention]
A constant potential electrolysis type electrochemical sensor such as a polarographic electrode 1A, a galvanic cell type electrode 1B, and the like is provided with the working electrode 4 and the counter electrode 7 as described above, and operates in accordance with oxidation or reduction reaction at the working electrode 4. The amount of current flowing between the pole 4 and the counter electrode 7 is measured. When measurement is performed, a circuit is formed in the electrolyte solution 6 and a stabilization time (aging time) is required until the electrode reaches an equilibrium potential and the reaction at the electrode is stabilized. When measuring the concentration, several days (eg, 3 days) may be required until a stable residual current is reached.
[0009]
Therefore, in order to enable the diaphragm type electrode to be used immediately after being attached to the apparatus main body, the circuit is connected in advance using a short plug, or the diaphragm type electrode is connected to the apparatus main body in advance. There is also a method for securing the aging time.
[0010]
However, such a method requires a power source (battery or the like) for applying a voltage and basically does not shorten the aging time. When the diaphragm electrode is used for the first time, a certain stabilization time is required. .
[0011]
In addition, when silver is used as the material for the counter electrode 7, the counter electrode 7 is covered with an insulating silver chloride (AgCl) along with the reaction, and the electrode life is shortened. ) And other considerations such as starting aging.
[0012]
For example, in the polarographic electrode 1A, when measuring the concentration of dissolved oxygen in a sample solution, silver is generally used for the counter electrode 7, but silver chloride is previously applied to the counter electrode 7 so that the counter electrode 7 is in an equilibrium state quickly. There is a method of plating. Thereby, since the counter electrode 7 reaches an equilibrium state relatively quickly, it is possible to measure oxygen having a high concentration such as atmospheric saturated water. However, when measuring oxygen in the order of μg / L, it may take several days (for example, about 3 days) for the residual current to decrease. This is presumably because the time required for the reduction reaction of the working electrode 4 to reach an equilibrium state is rate-limiting.
[0013]
That is, in the polarographic electrode 1A using a potassium chloride solution as the electrolytic solution 6, when silver is used for the counter electrode 7 and silver chloride plating is applied to the counter electrode 7 in advance, and silver is used for the working electrode 4, thin oxidation or halogen A film such as a chemical compound is formed on the working electrode 4. Since the working electrode 4 performs a reduction reaction, it is considered that it takes time for the film such as oxidation or halide formed on the working electrode 4 to be reduced to reach an equilibrium state.
[0014]
For example, once the diaphragm 3 is removed, the coating is removed with nitric acid, and then the electrolytic solution 6 is injected, the aging time is slightly shortened. Also, the aging time can be shortened by electrolytic treatment in a potassium chloride solution and reducing this film in advance. From these phenomena, it can be seen that the reduced state of the working electrode 4 is involved in the aging time.
[0015]
However, the treatment with nitric acid in advance as described above is very troublesome, and the operability is poor, for example, the working electrode 4 is oxidized unless the electrolytic solution 6 is injected immediately after the treatment with nitric acid. And it's dangerous. Further, reduction by electrolysis is complicated and very time-consuming, resulting in a complicated apparatus.
[0016]
Accordingly, an object of the present invention is to provide an electrolyte solution for a diaphragm type electrode and a diaphragm type electrode that can quickly reach a stable potential, shorten the aging time, and enable measurement in a short time regardless of the storage state of the electrode. And a method for stabilizing a diaphragm electrode.
[0017]
Another object of the present invention is to allow the working electrode to quickly reach the reduced state without pretreatment or the need for a power source such as a battery. It is an object to provide an electrolyte solution for a diaphragm electrode, a diaphragm electrode, and a method for stabilizing a diaphragm electrode, which can reduce and stabilize the residual current of the electrode over time.
[0018]
Another object of the present invention is to prevent the shortening of the electrode life due to the formation of silver chloride at the counter electrode, which is seen in the conventional method of securing the aging time by using the short plug to activate the electrode. An electrolyte solution for a diaphragm electrode, a diaphragm electrode, and a method for stabilizing a diaphragm electrode are provided.
[0019]
[Means for Solving the Problems]
In order to solve the above problems, the present inventor has intensively studied, for example, in a polarographic electrode using silver as a working electrode, by supplementing silver ions in the electrolyte solution of the diaphragm electrode, without performing pretreatment or the like. The present inventors have also found that the working electrode can be quickly brought into a reduced state without requiring a power source such as a battery.
[0020]
That is, the above object is achieved by the electrolyte solution for a diaphragm electrode, the diaphragm electrode, and the method for stabilizing a diaphragm electrode according to the present invention. In summary, according to the first aspect of the present invention, a chamber partitioned from the outside by a diaphragm that allows a gas to be measured in a sample to permeate is provided at one end of the electrode body, and a working electrode and a counter electrode are disposed in the chamber. A diaphragm-type electrode used for a diaphragm-type electrode for measuring the current flowing between the working electrode and the counter electrode when the gas to be measured that has permeated through the diaphragm reacts at the working electrode while the electrode and the counter electrode are present in the electrolyte An electrolyte solution for a diaphragm type electrode, comprising: a metal ion, a metal complex, or a metal compound of the same type as the metal constituting the working electrode.
[0021]
According to the second aspect of the present invention, the electrode body is provided with a chamber partitioned from the outside by a diaphragm that allows the gas to be measured in the sample to pass through, and the electrolyte solution is accommodated in the chamber and acts in the electrolyte solution. In the diaphragm type electrode for measuring the current flowing between the working electrode and the counter electrode when the measurement target gas that has passed through the diaphragm reacts at the working electrode, the working electrode is configured in the chamber. A diaphragm-type electrode is provided, in which an electrolytic solution containing in advance a metal ion, a metal complex, or a metal compound of the same type as the metal to be stored is accommodated.
[0022]
According to the third aspect of the present invention, the electrode body is provided with a chamber partitioned from the outside by a diaphragm that allows the gas to be measured in the sample to pass through, and the working electrode and the counter electrode are disposed in the chamber. A method for stabilizing a diaphragm-type electrode for measuring a current flowing between a working electrode and a counter electrode by reacting a gas to be measured that has permeated through the diaphragm in a state where the counter electrode is present in an electrolyte solution, There is provided a method for stabilizing a diaphragm type electrode, wherein an electrolytic solution to which a metal ion, a metal complex, or a metal compound of the same type as the metal constituting the working electrode is added is injected into the chamber.
[0023]
According to one embodiment of each of the present invention, the electrolytic solution contains the same kind of metal ions as the working electrode of the diaphragm electrode. In one embodiment, the electrolytic solution contains at least an alkali metal or alkaline earth metal halide and silver halide. The electrolytic solution may contain potassium chloride or sodium chloride and silver chloride or silver bromide.
[0024]
According to each embodiment of the present invention, the working electrode of the diaphragm electrode is made of silver, and the counter electrode is made of silver-silver chloride.
[0025]
In each embodiment of the present invention, the diaphragm electrode is a polarographic diaphragm electrode or a galvanic cell diaphragm electrode. The diaphragm-type electrode may be a diaphragm-type dissolved oxygen sensor. For example, the present invention is extremely effective in a device capable of measuring a dissolved oxygen concentration of 200 μg / L or less. Alternatively, the diaphragm-type electrode may be a diaphragm-type oxygen sensor. For example, the present invention is extremely effective when the oxygen concentration can be measured at 2% or less.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the electrolyte solution for diaphragm type electrodes, the diaphragm type electrode and the method for stabilizing the diaphragm type electrode according to the present invention will be described in more detail with reference to the drawings.
[0027]
Example 1
The diaphragm type electrode according to the present invention is preferably embodied in the polarographic type diaphragm type electrode (polarographic type electrode) shown in FIG. 2 and the galvanic cell type diaphragm type electrode (galvanic battery type electrode) shown in FIG. In this embodiment, the case where the present invention is applied to the polarographic electrode 1A shown in FIG. 2 as a dissolved oxygen gas sensor will be described.
[0028]
The polarographic electrode 1A includes a hollow cylindrical electrode body 2, a gas permeable diaphragm 3 fixed to the opening at the tip thereof, and a working electrode 4 disposed inside the electrode body 2 in the vicinity of the diaphragm 3. And a counter electrode 7 attached to the inner periphery of the support tube 5 that supports the working electrode 4. A chamber 2 a that is partitioned from the outside by the diaphragm 3 is formed between the electrode body 2 and the support tube 5. The electrolytic solution 6 is accommodated in the chamber 2a.
[0029]
For example, the support tube 5 made of glass is coaxially disposed inside the electrode, and the working electrode 4 is attached to the tip thereof. A slight gap having a constant thickness is formed between the diaphragm 3 and the working electrode 4 to form a layer (electrolytic solution layer) of the electrolytic solution 6 having a constant thickness.
[0030]
Lead wires 4 a and 7 a are connected to the working electrode 4 and the counter electrode 7, respectively. These lead wires 4 a and 7 a are led out through the support tube 5 and connected to a voltage application means (DC power supply) 8. . The gas to be measured that has passed through the diaphragm 3 reacts on the surface of the working electrode 4, and the electrolytic current of the dissolved gas flowing to the working electrode 4 at that time is measured by an ammeter 9 and is detected by the polarographic electrode 1 </ b> A. It is configured to measure the gas concentration. The measurement result is instructed by an indicator provided in the measuring apparatus main body (not shown). Alternatively, the measurement result may be printed out.
[0031]
Here, as described above, the polarographic electrode 1A measures the amount of current flowing between the working electrode 4 and the counter electrode 7 due to the reaction at the working electrode 4, but the reactions at the working electrode 4 and the counter electrode 7 are in an equilibrium state. A stabilization time (aging time) is required until it reaches the point of stabilization.
[0032]
In particular, for example, when the polarographic electrode 1A is used as a dissolved oxygen gas sensor for measuring the dissolved oxygen gas concentration in the liquid phase as in this embodiment, the concentration is as low as μg / L, more detailed. For measuring a concentration of 200 μg / L or less (0 to 200 μg / L) (when used as an oxygen gas sensor for measuring the oxygen gas concentration in the gas phase, measuring a concentration of 2% or less (0 to 2%) In order to reliably reduce the residual current, it has conventionally been time consuming and troublesome.
[0033]
On the other hand, according to the present invention, the residual current can be reduced very easily and quickly, and the working electrode 4 and the counter electrode 7 can be brought into an equilibrium state. This will be described in detail below.
[0034]
According to the present invention, the electrolyte 6 accommodated in the chamber 2a of the polarographic electrode 1A contains a metal that is the same type of metal as the metal constituting the working electrode 4 or a metal that contains the same type of metal as the metal constituting the working electrode 4. A complex or a metal compound is contained.
[0035]
The base of the electrolytic solution 6 is not different from that conventionally used. That is, as generally used in this field, alkali metal or alkaline earth metal halides can be used. Other suitable electrolyte solutions are acceptable. For example, potassium chloride, sodium chloride and the like are suitable for practical use. The concentration of the electrolyte solution 6 serving as the base can be any concentration suitable for exhibiting the function of the electrode, but is generally about 0.5 mol / L in this field.
[0036]
More specifically, in this example, silver (Ag) was used for the working electrode 4 and silver-silver chloride (Ag / AgCl) (silver plated with silver chloride) was used for the counter electrode 7. In this case, as the electrolytic solution 6, a material containing at least an alkali metal or alkaline earth metal halide and silver halide is preferably used in practice. As the alkali metal or alkaline earth metal halide, potassium chloride and sodium chloride are practically preferable. As the silver halide, silver chloride and silver bromide are suitable for practical use.
[0037]
In this example, as the electrolytic solution 6, a potassium chloride solution containing silver ions (Ag ⁺ ) that are the same kind of metal ions as the working electrode 4 was used. Silver ions were supplied by dissolving silver chloride.
[0038]
If suitable for the purpose of the present invention, the concentration of silver chloride added to the electrolytic solution 6 is arbitrary, but in this example, a solution obtained by saturating an aqueous potassium chloride solution with silver chloride was used as the electrolytic solution 6. That is, here, an excessive amount of an appropriate amount of silver chloride powder was added to a potassium chloride solution having a predetermined concentration, and the mixture was stirred and allowed to stand. The supernatant was separated and used as the electrolytic solution 6.
[0039]
Although silver chloride is sparingly soluble, it has been confirmed that the present invention works suitably, for example, with the amount of silver ions provided in the electrolyte 6 by the above method. In addition, in the electrolyte solution 6 used as a potassium chloride solution, for example, silver chloride dissolves more than in pure water.
[0040]
However, the method for preparing the electrolytic solution 6 is preferable in that it can easily prepare a saturated solution of hardly soluble silver chloride, but the present invention is not limited to this. For example, the electrolytic solution 6 to be prepared is prepared. It is of course possible to measure a predetermined amount of silver chloride into the electrolytic solution 6 in accordance with the amount. Further, if it is suitable for the purpose of the present invention, the silver ion may be in a smaller amount (low concentration).
[0041]
Thus, by replenishing the electrolytic solution 6 with silver ions in advance, the electrode stabilization time can be dramatically shortened. Although not intended to be bound by any particular theory, it is believed that this is because the working electrode 4 reduces silver ions in the electrolyte 6 and quickly reaches an equilibrium state.
[0042]
At this time, when a thin film of oxide or halide is formed on the surface of the working electrode 4, it is considered that silver is deposited together with or overlapping with these.
[0043]
Thus, since the silver ions in the electrolytic solution 6 are reduced to become the same metallic silver as the material of the working electrode 4, the material of the working electrode 4 does not change. Further, in this embodiment, since silver is used for the working electrode 4 and the counter electrode 7, even if silver chloride is added to the electrolytic solution 6, the reaction at the working electrode 4 and the counter electrode 7 necessary for measurement is inhibited. And stabilization time can be shortened.
[0044]
In the polarographic electrode 1A, the electrolytic solution 6 is injected into the chamber 2a so that the working electrode 4 and the counter electrode 7 are present in the electrolytic solution 6, so that the electrode and the electrolytic solution are consumed. Therefore, it is desirable that the polarographic electrode 1A is injected with the electrolyte 6 into the chamber 2a while ensuring an aging time before the first use. Further, the electrolytic solution 6 may be replaced for the purpose of maintenance of the polarographic electrode 1A.
[0045]
In such a case, according to the present invention, the ions of the same type of metal as the metal constituting the working electrode 4 as described above, or the metal constituting the working electrode 4 are provided in the chamber 2 a partitioned from the outside by the diaphragm 3. By applying a method for stabilizing a diaphragm electrode comprising injecting an electrolytic solution 6 to which a metal complex or metal compound containing the same kind of metal is added, reaction at the time of measurement at the working electrode 4 and the counter electrode 7 is inhibited. Without this, the pole can be easily and quickly brought into an equilibrium state.
[0046]
During aging, the polar electrode 1A may be connected to a circuit using a short plug, or may be connected to a measurement main body to be in an operating state. However, the electrolysis according to the above-described present invention is not performed in the chamber 2a. It was confirmed that the aging time can be drastically shortened by injecting the liquid 6 and leaving it to stand as compared with the conventional case.
[0047]
If it is acceptable from the viewpoint of consumption of the electrolytic solution 6 or the like, the polarographic electrode 1A may have ions of the same kind of metal as the metal constituting the working electrode 4 or the working electrode 4 before the first use. An electrolytic solution 6 containing a metal complex containing the same kind of metal as the constituent metal or a metal compound in advance can be accommodated in the chamber 2a, and the working electrode 4 and the counter electrode 7 can be provided in the electrolytic solution 6. .
[0048]
(Test example)
Next, the results of one test example in which the aging time of the polarographic electrode 1A is compared between the present example and the conventional example will be shown.
[0049]
In the polarographic electrode 1A, except for the electrolytic solution 6, the area, material, and the like of the working electrode 4 and the counter electrode 6 were the same in this example and the conventional example. The detailed settings of the various elements were as follows.
[0050]
・ Working electrode: Ag
Outer diameter φ5mm
・ Counter electrode: Ag / AgCl (plating)
Outside diameter φ12mm
Axis length 15mm
-Applied voltage: -900 mV (between working electrode and counter electrode)
・ Electrolyte:
Example 0.5 mol / L KCl, saturated AgCl
Conventional example 0.5 mol / L KCl
[0051]
The polarographic electrode 1A of the present example and the conventional example having the above-described configuration was connected to the apparatus main body to be in an operating state, and the transition of the residual current was measured over time. The results are shown in FIG.
[0052]
As shown in FIG. 1, the polarographic electrode 1A of this example was stabilized in less than one day. On the other hand, in the conventional example, it took approximately 5 to 6 days to stabilize. As is apparent from this result, according to the present embodiment, the residual current decreases in a very short time compared to the conventional example, and a stable state is reached.
[0053]
Here, for the sake of convenience of residual current measurement, the polarographic electrode 1A is connected to the apparatus main body and the aging is performed in the operating state. However, as described above, the electrolytic solution according to the present embodiment is replaced with the conventional electrolytic solution. By simply injecting 6 into the chamber 2a, the aging time is dramatically reduced.
[0054]
As described above, according to the present invention, the pole can be quickly reached to a stable potential, the aging time can be shortened, and the measurement can be performed in a short time regardless of the storage state of the electrode. As described above, according to the present invention, the working electrode can be quickly brought into the reduced state without performing pretreatment or the like, and without requiring a power source such as a battery, and a short plug is used. Unlike the conventional method of ensuring the aging time by putting the electrode in the working state, the electrode storage state can be obtained by simply dissolving silver ions in the electrolyte without shortening the electrode life due to the generation of silver chloride on the counter electrode. Regardless of this, it is possible to stabilize in a short time and to reduce the residual current. As described above, the present invention is very useful particularly in a diaphragm type electrode for low concentration measurement where it is necessary to reliably reduce the residual current.
[0055]
In the above description, the case where the present invention is embodied in a polarographic diaphragm electrode (polarographic electrode) 1A has been described. However, a galvanic cell diaphragm electrode (galvanic cell electrode) as shown in FIG. It can be equally applied to 1B, and the same effect can be obtained.
[0056]
In the above description, the case where silver is used as the working electrode 4 has been described. However, the present invention is not limited to this. Even when platinum (Pt) or gold (Au) is used as the working electrode 4, a metal complex or metal containing the same kind of metal ion as the metal constituting the working electrode 4, or the same kind of metal as the metal constituting the working electrode 4 By adding the compound to the electrolytic solution 6, the same effect as described above can be obtained.
[0057]
Further, in the above-described embodiments, the present invention has been described as being a dissolved oxygen gas sensor, but the present invention is not limited to this. For example, the present invention is used as a gas phase oxygen gas sensor, an ozone gas sensor, a chlorine dioxide gas sensor, or the like. The electrode can be suitably embodied.
[0058]
【The invention's effect】
As described above, according to the present invention, the electrolyte for the diaphragm electrode for use in the diaphragm electrode constitutes ions of the same kind of metal as the working electrode of the diaphragm electrode or the working electrode. Because it contains a metal complex or metal compound containing the same type of metal as the metal to be used, the pole can be quickly reached to a stable potential, the aging time can be shortened, and measurement can be performed in a short time regardless of the storage state of the electrode. State. In addition, the working electrode can quickly reach the reduced state without pretreatment or the need for a power source such as a battery, and the residual current of the electrode can be achieved in a short time regardless of the storage state of the electrode. Can be stabilized. Further, it is possible to prevent the shortening of the electrode life due to the generation of silver chloride at the counter electrode, which is seen in the conventional method of securing the aging time by using the short plug to activate the electrode. According to the present invention, there are also provided a diaphragm-type electrode and a method for stabilizing a diaphragm-type electrode using the electrolyte solution for a diaphragm-type electrode of the present invention, each corresponding to the effects obtained with the electrolyte solution for a diaphragm-type electrode. Effect can be obtained.
[Brief description of the drawings]
FIG. 1 is a graph showing the effect of a diaphragm electrode according to the present invention.
FIG. 2 is a schematic sectional view of a polarographic diaphragm electrode to which the present invention can be applied.
FIG. 3 is a schematic sectional view of a galvanic cell type diaphragm electrode to which the present invention can be applied.
FIG. 4 is a graph for explaining the operation of the diaphragm type electrode.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Diaphragm type electrode 2 Electrode main body 3 Diaphragm 4 Working electrode 5 Support pipe 6 Electrolyte 7 Counter electrode 8 Power supply 9 Ammeter

Claims (30)

One end of the electrode body is provided with a chamber partitioned from the outside by a diaphragm that allows the gas to be measured in the sample to pass through, and the working electrode and the counter electrode are disposed in the chamber, and the working electrode and the counter electrode are present in the electrolyte. In the electrolyte solution for the diaphragm type electrode used for the diaphragm type electrode for measuring the current flowing between the working electrode and the counter electrode when the gas to be measured that has passed through the diaphragm reacts at the working electrode.
An electrolyte solution for a diaphragm-type electrode, comprising a metal ion, a metal complex, or a metal compound of the same type as the metal constituting the working electrode of the diaphragm-type electrode. The electrolyte solution for a diaphragm type electrode according to claim 1, comprising the same kind of metal ions as the working electrode of the diaphragm type electrode. 3. The electrolyte solution for a diaphragm type electrode according to claim 2, comprising at least an alkali metal or alkaline earth metal halide and silver halide. 4. The electrolyte solution for a diaphragm type electrode according to claim 3, comprising potassium chloride or sodium chloride and silver chloride or silver bromide. 5. The electrolyte solution for a diaphragm type electrode according to claim 3, wherein the working electrode of the diaphragm type electrode is made of silver and the counter electrode is made of silver-silver chloride. 6. The electrolyte solution for a diaphragm type electrode according to claim 1, wherein the diaphragm type electrode is a polarographic diaphragm type electrode or a galvanic cell type diaphragm type electrode. 7. The electrolyte solution for a diaphragm type electrode according to claim 6, wherein the diaphragm type electrode is a diaphragm type dissolved oxygen sensor. The electrolyte solution for a diaphragm type electrode according to claim 7, wherein the diaphragm type electrode is capable of measuring a dissolved oxygen concentration of 200 µg / L or less. The electrolyte for a diaphragm type electrode according to claim 6, wherein the diaphragm type electrode is a diaphragm type oxygen sensor. The electrolyte solution for a diaphragm type electrode according to claim 9, wherein the diaphragm type electrode can measure an oxygen concentration of 2% or less. One end of the electrode body is provided with a chamber partitioned from the outside by a diaphragm that allows the gas to be measured in the sample to pass through. The electrolyte is accommodated in the chamber, and the working electrode and the counter electrode are disposed in the electrolyte. In the diaphragm type electrode for measuring the current flowing between the working electrode and the counter electrode by reacting the gas to be measured that has passed through the working electrode,
A diaphragm type electrode, wherein an electrolytic solution containing in advance a metal ion, a metal complex, or a metal compound of the same type as the metal constituting the working electrode is accommodated in the chamber. The diaphragm type electrode according to claim 11, wherein the electrolytic solution contains metal ions of the same kind as the working electrode in advance. 13. The diaphragm type electrode according to claim 12, wherein the electrolytic solution contains at least an alkali metal or alkaline earth metal halide and silver halide in advance. The diaphragm type electrode according to claim 13, wherein the electrolytic solution contains potassium chloride or sodium chloride and silver chloride or silver bromide in advance. The diaphragm type electrode according to claim 13 or 14, wherein the working electrode is made of silver and the counter electrode is made of silver-silver chloride. The diaphragm type electrode according to any one of claims 11 to 15, which is a polarographic diaphragm type electrode or a galvanic cell type diaphragm type electrode. The diaphragm type electrode according to claim 16, which is a diaphragm type dissolved oxygen sensor. The diaphragm type electrode according to claim 17, wherein the dissolved oxygen concentration can be measured at 200 µg / L or less. The diaphragm type electrode according to claim 16, which is a diaphragm type oxygen sensor. 20. The diaphragm type electrode according to claim 19, wherein an oxygen concentration of 2% or less can be measured. One end of the electrode body is provided with a chamber partitioned from the outside by a diaphragm that allows the gas to be measured in the sample to pass through, and the working electrode and the counter electrode are disposed in the chamber, and the working electrode and the counter electrode are present in the electrolyte. A method for stabilizing a diaphragm-type electrode for measuring a current flowing between a working electrode and a counter electrode when a gas to be measured that has passed through the diaphragm reacts at the working electrode,
A method for stabilizing a diaphragm-type electrode, wherein an electrolytic solution to which a metal ion, a metal complex, or a metal compound of the same type as the metal constituting the working electrode is added is injected into the chamber. The method for stabilizing a diaphragm type electrode according to claim 21, wherein the electrolytic solution contains the same type of metal ions as the working electrode of the diaphragm type electrode. 23. The method for stabilizing a diaphragm electrode according to claim 22, wherein the electrolytic solution contains at least an alkali metal or alkaline earth metal halide and silver halide. The method for stabilizing a diaphragm type electrode according to claim 23, wherein the electrolytic solution contains potassium chloride or sodium chloride and silver chloride or silver bromide. The method for stabilizing a diaphragm electrode according to claim 23 or 24, wherein the working electrode of the diaphragm electrode is made of silver and the counter electrode is made of silver-silver chloride. The method for stabilizing a diaphragm type electrode according to any one of claims 21 to 25, wherein the diaphragm type electrode is a polarographic diaphragm type electrode or a galvanic cell type diaphragm type electrode. 27. The method of stabilizing a diaphragm type electrode according to claim 26, wherein the diaphragm type electrode is a diaphragm type dissolved oxygen sensor. 28. The method for stabilizing a diaphragm type electrode according to claim 27, wherein the diaphragm type electrode is capable of measuring a dissolved oxygen concentration of 200 [mu] g / L or less. 27. The method according to claim 26, wherein the diaphragm electrode is a diaphragm oxygen sensor. 30. The method of stabilizing a diaphragm electrode according to claim 29, wherein the diaphragm electrode can measure an oxygen concentration of 2% or less.

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