JPS6053841A - Electrode apparatus for measuring concentration of hydrogen ion - Google Patents

Abstract

PURPOSE:To obtain a stable H<+> measuring electrode apparatus having quick response speed, by sequentially laminating a porous film, a platinum film, and a hydrogen-ion selecting and transmitting film from the inside of a tube at one opening end of a tubular body comprising an insulating material, thus providing an H<+> ion response film structure, and passing hydrogen gas in the tube. CONSTITUTION:A hydrogen-ion-concentration response-film structure 12 is attached to one end of a tube 11 comprising an insulating material such as polycarbonate so as to cover the opening part of the tube 11 by using an insulating material 13 such as epoxy resin. The response-film structure 12 is formed by laminating the following films, a porous film 12 comprising fluorine or the like, a Pt film 12b formed by evaporating Pt on the film 12a, and an H<+> ion selecting and transmitting film 12c, which is formed by electrolytic-oxidation polymerization of a poly (hydroxy) aromatic compound and an aromatic compound including N such as poly (1,2-diamino benzene). The structure 12 is attached so that the film 12c is contacted with a sample liquid. On the other end of the tube 11, a stopper 15, which is provided with an H2-gas introducing pipe 16a and an exhaust pipe 16b, is fixed. A lead wire 14 is attached to the platinum film 12a beforehand. Thus a compact sensor and the like, wherein an electrode is miniaturized, and which can be inserted into the living body, can be obtained.

Description

[Detailed description of the invention] ■Background of the invention 〔Technical field〕 The present invention relates to an electrode device for measuring hydrogen ion concentration.

[Prior art and problems]

It has become important in the medical field to obtain information inside the body by inserting sensors directly into the living body by miniaturizing electrodes, and by using them in conjunction with other disposable devices. Furthermore, it is difficult to analyze microscopic samples or samples with high viscosity using commercially available glass membrane electrodes. Therefore, it has been proposed to solve the above problems by using a membrane electrode in which the surface of the wire electrode is directly coated with a polymer film. These membrane electrodes have the following characteristics: 1) ions remain in the measurement solution, and the 411j
This causes measurement errors in constant solutions (this is called the memory effect). 2) Problems such as slow response time for ions to diffuse through the polymer membrane and reach the surface of the sensitive membrane (here, platinum-based metal conductor) are desired to be improved. Ta.

(Objective of the Invention) Objective of the Invention: To provide an apparatus capable of stably measuring hydrogen ion concentration without adversely affecting the sample liquid and with a short response time.

According to the invention, there is provided a hollow body formed of an insulating knife, a hydrogen ion concentration sensitive membrane structure that closes an opening communicating between the inside and outside of the hollow body, a porous membrane, and a porous membrane + 1 outside the membrane. (Equipped with a platinum membrane broken on the side surface, a hydrogen ion selectively permeable membrane formed on the platinum membrane, and four mechanisms for introducing hydrogen gas into the hollow body.) ,
An electrode device is provided for measuring hydrogen ion enrichment in a liquid by the potential response in the platinum membrane.

Generally, the hydrogen ion selectively permeable membrane is an electrolytically oxidized polymer membrane of at least one aromatic compound selected from the group consisting of hydroxy aromatic compounds and nitrogen-containing aromatic compounds, and is formed directly on a platinum membrane. What was done and what was done
A polymer compound film formed on a sleep-deoxidizing polymer film and/or
or an inorganic compound film.

Further, the above-mentioned hydrogen gas introduction structure usually includes a first pipe for introducing hydrogen gas into the hollow body and a second pipe for leading out excess hydrogen gas from the hollow body.

Further, in one embodiment of the present invention, hydrogen gas inlet pipes are installed on the porous membrane side at intervals of about one chamber, and the hydrogen ion concentration in the measurement liquid is measured through the hydrogen ion selectively permeable membrane. An electrode device for measuring hydrogen ion concentration is provided that allows selective permeation onto the platinum surface and measures hydrogen ions on the platinum surface using a potential response based on a reduction reaction.

■Detailed explanation of the invention Hereinafter, this invention will be explained in detail based on the drawings.

FIG. 1 shows the basic structure of an electrode device for measuring hydrogen ion concentration according to the present invention. As shown, this electrode device 10 is made of an insulating material (e.g. polycarbonate*
x x x + 71? It is provided with a hollow body, for example, a tube, which is open at both ends and is made of lysolobirene, etc.).

A hydrogen ion concentration sensitive membrane structure 12 is provided by closing one end of the tube 1. The sensitive membrane structure 12 includes, in order from the inside of the tube 11, a porous membrane 12a1, a platinum membrane 1,
2b and a hydrogen ion selectively permeable membrane 12C are laminated.

The porous membrane 12a acts as a support for the platinum membrane 12b,
Further, hydrogen gas is allowed to freely permeate through the platinum film 12b. Such a porous membrane 12m is made of a fluorine-containing polymer (for example, polyvinylidene fluoride, xxxx).
, cellulose polymers (e.g., nitrocellulose, regenerated 5-cellulose), rj5lJ vinyl chloride and its copolymers (e.g., poly(iM chemical engineering nylethylene)),
Polyvinylidene chloride, silicone, polyacrylonitrile and copolymers thereof (1+!I, for example, acrylonitrile-butadiene) L9' are used. This porous membrane 12a is made of a gas-permeable carrier (not shown) such as a nonwoven fabric.
may be compatible with each other.

The pore diameter of the porous membrane 1211 is 0.005 to 1101t,
Its thickness is 50 μn1~1. Preferably OM.

The platinum film 12b is deposited on the porous film 12a by sputtering,
This can be done by vacuum accumulation methods such as vapor deposition and ion blating.

The hydrogen ion permeable membrane 12c is in contact with a solution whose hydrogen ion concentration is to be measured and allows the hydrogen ions in the solution to permeate therethrough. Such a hydrogen ion permeable membrane 12c may be made of poly(hydroxy aromatic compound) such as Iq
IJ phenol, poly(nitrogen-containing aromatic compound) such as yjelJ (1°2-diaminobenzene) or a copolymer thereof, polycarbonate, poly(vinyl aromatic compound)
For example, polystyrene, anionic or cationic derivatives thereof such as poly(vinylpyridine) quaternized products, I-reathers, polyurethanes, etc. are used. The thickness of this film 12c is preferably 0.05 μm to 0.2 wn.

A plug body 15 is installed to close off the upper end of the hollow body 1. A pipe 1 for introducing hydrogen gas passes through this stopper 15.
6h and a discharge pipe 16b are installed inside the hollow body 11. The distance t between the lower end of the pipe 16yL and the porous membrane 12m is preferably about one inch.

A lead 6 is connected to the platinum film 12h via an insulating material (for example, xxxx) 73 that covers the lower part of the hollow body 11 and the peripheral edge of the sensitive film structure 12.

■Specific Effects of the Invention To measure the hydrogen ion concentration in a solution using the above-mentioned electrode device, place the electrode device 10 together with a reference electrode (for example, a sodium chloride saturated calomel electrode) into the sample liquid, and The IO lead wire 14 and the reference electrode are connected to a voltmeter, and the electromotive force of the electrode device (electrode potential on the platinum film) with respect to the reference electrode is read. Based on this potential value, the electrode equilibrium potential pair p! (The PIl value can be known from the value relationship νI.

The hydrogen ion permeable membrane 12c is made of poly(hydroxy aromatic compound) and/or poly(oxygen-containing aromatic compound)
An electrolytic oxidation polymer film formed directly on the platinum film 12b, and a hydrophobic film (for example, polycarbonate) formed on this polymer film, or a hydrophobic film and a hydrophilic film (for example, 71? (HiroxyC4-C6 alkyl (meth)
It is preferable to use a multilayer film in combination with acrylate (acrylate, etc.).

The tube 11 and the sensitive film structure 12 are preferably fixed with an insulating adhesive J3 such as epoxy resin. A lead wire 14 connected to the platinum film 12b through the insulating adhesive 13 is led out to the outside.

The other open end of the cheap 1 is sealed with an airtight closure 15, and the porous membrane 12m is passed through this closure 15.
Reaching the vicinity - The flat tube 16a and the i4 tube 16b are inserted into the tube full. Hydrogen gas is introduced into the tube 11 from the via' 16 m, and excess gas is
It is discharged from the iguage 16b.

Example 1 Platinum was applied to the surface (121L in Fig. 1) of a polyvinylidene fluoride porous membrane (Diafilter M type manufactured by Biomedical Co., Ltd.) supported on a polyethylene nonwoven fabric to a thickness of 0.04μ.
Sputtering method (dipolar high speed sputtering method (200WX1)
The bond broke in 5 seconds)). This porous membrane supported platinum membrane was connected to a shunt connector (polycarbonate y
It was installed to cover the opening of a hollow body made of Nate (opening diameter 3 mm) and fixed with epoxy resin 13. A copper wire was previously connected to the end of the platinum film using silver paste to form a lead wire 14. Pipe 16a reaching near porous membrane 121L
(made by xxxx), 9- Set the exhaust pipe 16b (xxxx), and
16a had a diameter of 1 mm and was set on a porous membrane 12h. Poly(phenol-1,2-
diaminobenzene) electrolytically oxidized polymer film was formed.

Platinum coated membrane electrode obtained on working electrode 2 Reference electrode: saturated calomel electrode Counter electrode: Platinum mesh electrolyte: methanol solution containing 5mM phenol, 5mM 1.2-diaminobenzene and 30mM sodium hydroxide. Before electrolysis, oxygen was sufficiently removed with argon gas.

In other words, the applied voltage is 0■ or 1? After confirming that the oxidation reaction of phenol and 1,2-diaminobenzene was occurring on the platinum film by scanning between saturated calomel electrodes (SCE), the applied voltage was increased to 1.0 telt. (vs. SCE), and constant potential electrolysis was carried out for 3 minutes to form the desired electrolytic acid 10-containing compound 11&i on the platinum membrane.The stiffness was collected three times with distilled water and washed I7.

Next, soil WI−: Tri: l oxidation i, [i combination f
high frequency snow and ivy device id (2o o w
x minutes), the polycarbonate membrane was
A thickness of 2 μm was deposited. After that, this 11? liquor 7
A methanol solution of poly 2-hydroxyethyl methacrylate (P-HEMA) (concentration 0.5
'tri: bt%) Cast 1 μl, p-■r
gMAlla (thickness: 01 μm) was formed. This P-
The periphery of the thus obtained electrode structure P-T (F, MA film except for a predetermined surface) was irradiated with a resin.
The other end of the electrode structure connector was hermetically sealed with a stopper, and a hydrogen gas introduction pipe and a discharge pipe were assembled as shown in FIG. 1 to obtain a desired electrode device.

The thus obtained '11f, electrode device - was used with a standard phosphate buffer solution (P116.8) together with a silver/silver chloride electrode as a reference electrode.
6) was inserted into a circulating flow cell, and the influence of dissolved oxygen gas pressure (PO2) in the measurement liquid on the IL equilibrium potential of hydrogen ion measurement was investigated. The results are shown in Table 1. In addition,
Hydrogen gas was introduced into the electrode apparatus at 760 mm Hg.

*Time measurement temperature until equilibrium potential value reaches almost constant value 3
It was carried out at 7℃±1℃.

As a result, if the oxygen concentration is up to Po2600 mmHg, it will not be affected by dissolved oxygen, and the response speed will be fast.

Next, using the above electrode device, we measured the change in the normal range value when the pH of the phosphate standard buffer solution was changed from 4.0 to 80, and found that Po2 was 192 inHg and 259 inHg.
A linear relationship with a slope of 35 mV was obtained. Moreover, the response time of the equilibrium potential at this time was within 1 minute. - Over a wide range of C1 hydrogen ion concentrations, Po2 was up to 259 +
Up to mmHg, tl measurement is possible without being affected by Po2.

Implementation 112 A desired electrode device was prepared in the same manner as in Example 1 except that the polycarbonate film was not ruptured.

P in the same manner as in implementation I+l11. Table 2 shows the results of examining the influence of 2.

As a result, even in the high 02 concentration region of Po2.600 mmHrr, Po2.9 mnHg 02 ? Even in the /11 degree low region, the equilibrium 13- potential value hardly changes, and it is possible to keep )(+is+++ constant).

In addition, as in Example 1, the relationship between l-old straight and flat 1 versus 'spiral 1' was investigated, and as a result, a linear relationship with a slope of 44 mV7'i+Il was obtained. Note that the response time of the equilibrium potential was within 1 minute.

Example 3 The electrode device of Example 1 (M Series 1) was installed in an extracorporeal circulation circuit that returns arterial blood from the Kei artery of a rabbit to the Gei vein via the blood circuit, and the equilibrium potential value of the electrode of the present invention was determined to be equal to P in the blood. .2
We investigated to what extent it is affected by A kg/AgC1 electrode with a liquid junction made of an agar-salt bridge was used as a reference electrode. Po2 changes in blood were measured using a hollow fiber oxygenator. The total gas pressure introduced into the oxygenator was 760 tnrnHg.
(PO2 + PCO2 0 pN2) constant and Pco2
is maintained at a constant value of 40 wnHg and Po2 is set to RI7.1.
It was knotted. Also P. 2 was measured using a blood pressure gas measuring device manufactured by Radiometer.

The experimental results are shown in Table 3.

14-Table 3 1 50.7-(i43.1 7.4512 108
．． 2 -650.6 7.1163 112.5 -6
55.0 7. ], 584 153.3 -656.4
7.1605], 97.8 -647.6 7.1
546 296 -623.5 7.1517 449
-574.8 7.1538 561 -563.9
7.1689 67.5 -569.1. 7.1.
6610 428 -545.9 7. ], 6411
69.4 -576.7 7.15812 425 -
549.7 7.16413 199.9 -568.
9 7.15014 235.1 -567.2 6.
76815 270.0 -563.4 6.530 From the results in Table 3, at Po2200 mmHg1, the electrode potential value (hexavalent) is hardly affected by the dissolved acid level. However, when Po2 exceeds 200 mm Hg, the E value becomes P
It has become clear that the temperature is affected by the O2 concentration.

Run u4 Run 1 except that no poly-etherhexyl methacrylate (P-HEMA) film was formed.
A desired electrode device was produced in the same manner as above. Then, since H2 gas was flowed near the porous membrane at a flow rate of 10 tnl/g, the ``+'' concentration was measured.

Using this electrode device, P was carried out in the same manner as in Example 1+11 and Example 3 (however, the test animal was a dog). When the influence of 2 concentration changes on the equilibrium potential value was investigated, the results shown in Tables 4 and 5, respectively, were obtained.

Human 5 (Canine arterial blood) Equilibrium potential values and P shown in Table 4. When the relationship with 2 was plotted, a linear relationship as shown by 8 in Figure 2 was obtained.

5 mV/log Po2. It was found that the influence of dissolved oxygen partial pressure was extremely small. Note that the response speed at which the equilibrium potential reaches a constant level is within 5 minutes.

In addition, the equilibrium potential value and PII change (previously commercially available Pi
(Standard buffer W* measured with a meter) satisfies the Nernst relation, and this II! The slope of the line is 44mV/l)H
17-- (37°C).

In addition, the equilibrium potential value and P shown in Table 5. When the relationship with 2 was plotted, the relationship shown by the line in FIG. 2 was obtained. As can be seen from this, P until Po2=200mnHg.

2Although it is hardly affected by partial pressure, 200 m
There was a tendency for the equilibrium potential value to rise rapidly above mHg. Therefore, the membrane composition electrode of the present invention has Po 2 ""
Blood Pl] value can be measured if it is within 20 OmmHg. The response speed in this case is within 1 minute.

Example 5 In the same electrode device as in Example 4, the relationship between the conditions during the production of the ion image retention film and the measured (P021B) value was investigated. Equilibrium potential value (measurement temperature 37°C ± 0.1°C) and P when changing the sputtering conditions (power consumption Watt x sputtering time) when coating a polycarbonate film. 2 (dissolved oxygen partial pressure in standard buffer) was investigated (see Table 6).

18- (1) Specific Effects of the Invention As described above, by using the electrode device of the present invention, the hydrogen ion sputum content in the specimen fluid can be stably measured with less influence of dissolved oxygen in the specimen fluid. However, the response time is still short. Furthermore, since hydrogen gas is not directly blown into the sample liquid, the degree of adverse effect on the sample liquid is small.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an electrode device for measuring hydrogen ion concentration according to the present invention, and FIG. 2 is a graph diagram showing the characteristics of the electrode device according to the present invention. 1 No. Hollow body, 12a Porous membrane, 12b...
・Platinum membrane, 12c... Hydrogen ion selective permeation membrane, 14・
...Lead wire, 13...Insulating material, 16a...Gas suction pipe, 16b...Gas discharge pipe opening, 15...Filling frame.

Claims (3)

[Claims] (1) A hollow body formed by mutually insulating bonding, a hydrogen ion concentration-sensitive membrane structure that closes one part of the opening that communicates between the inside and outside of the hollow body, and includes a porous membrane and an outer surface of the porous membrane. and a hydrogen ion selectively permeable membrane formed on the platinum membrane, and a mechanism for introducing hydrogen gas into the hollow body. An electrode device that measures the hydrogen ion concentration in a liquid using potential response. (2) The hydrogen ion selectively permeable membrane is an electrolytically oxidized 1.11 composite membrane of at least one aromatic compound selected from the group consisting of hydroxy aromatic compounds and nitrogen-containing aromatic compounds, and the hydrogen ion permselective membrane is platinum-based. An electrode device according to claim 1, comprising an electrode device formed directly on a membrane, and a hydrophobic membrane or a combination of a hydrophobic membrane and a hydrophilic membrane formed on this electrolytic oxidation polymer membrane. . (3) a first pipe in which a hydrogen gas introduction mechanism communicates with the inside and outside of the hollow body and introduces hydrogen gas into the vicinity of the inner surface of the porous membrane;
3. The electrode device according to claim 1, further comprising a second pipe for extracting excess hydrogen gas from the hollow body.