JP2003090816A - Composite electrode for measuring ion concentration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite electrode for measuring the ion concentration which can be easily miniaturized at a low cost. SOLUTION: A plurality of capillaries 1, etc., of glass composition having the ion conductivity are bundled in a substantially cylindrical stem tube 2, one end side of the bundled capillaries 1, etc., is electrically connected to each other by a conductor 3, and a reference electrode R with a lead wire 4 for taking out the reference electric potential connected to the conductor 3, and a glass electrode G in which a response film 7 is provided in a part of a cylindrical body 6 to form a space for storing the internal solution 5 is provided between the stem tube 2 and the reference electrode, and an internal electrode 8 is provided in the internal solution 5 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite electrode for measuring ion concentration, which is formed by integrating a glass electrode and a reference electrode.

[0002]

2. Description of the Related Art As a conventional composite electrode for measuring ion concentration, which is formed by integrating a glass electrode and a reference electrode, the glass electrode is a glass electrode internal liquid and a glass electrode immersed in the glass electrode internal liquid. Internal electrode and a supporting tube containing the glass electrode internal liquid and having a responsive film formed on a part thereof, wherein the reference electrode is the reference electrode internal liquid and the reference electrode internal liquid. An internal electrode for the reference electrode to be immersed, and a support tube containing the internal liquid for the reference electrode and having a liquid junction, and supporting the glass electrode so as to surround the outer circumference of the support tube forming the reference electrode. There is a double pipe structure in which a pipe is provided and both are coaxially arranged.

[0003]

However, since the conventional composite electrode for measuring ion concentration having the above structure has the double tube structure as described above, each of the glass electrode and the reference electrode is When it is attempted to manufacture a minute composite electrode by reducing the inner diameter of the support tube, an extremely skilled person must process it, resulting in a problem that the manufacturing cost becomes very high.

The present invention has been made in consideration of the above problems, and an object thereof is to provide a composite electrode for measuring ion concentration, which can be easily downsized at low cost. Is.

[0005]

In order to achieve the above object, a composite electrode for measuring ion concentration of the present invention comprises a plurality of capillaries having a glass composition having ion conductivity, which are focused in a substantially cylindrical stem tube. , While electrically connecting one end of the focused capillary with a conductor,
A reference electrode formed by connecting a lead wire for extracting a reference potential to the conductor, and a response film provided on a part of a cylinder forming a space for containing an internal liquid between the stem tube and And a glass electrode provided with an internal electrode in the internal liquid (claim 1).

Further, a plurality of capillaries having a glass composition having ion conductivity are focused in a substantially cylindrical stem tube, and one end of the focused capillaries is electrically connected by a conductor, and a reference potential is taken out. A reference electrode formed by connecting the lead wire to the conductor, and a response film on a part of the cylinder surrounding the outer peripheral surface of the stem tube, and after the inner surface of the cylinder is fluorinated by A
An AgCl layer may be formed by reacting with g ⁺ ions, and a glass electrode formed by electrically connecting a lead wire for extracting a measurement potential to the AgCl layer may be provided (claim 2).

Further, a plurality of capillaries having a glass composition having ionic conductivity are focused, one end of the focused capillaries is electrically connected by a conductor, and a lead wire for extracting a reference potential is used as the conductor. A reference electrode connected to the capillary and a response film on a part of the cylinder surrounding the capillary are formed, and the outer surface of the cylinder is subjected to fluoridation and then reacted with Ag ⁺ ions to form an AgCl layer. Further, a glass electrode in which a lead wire for measuring potential extraction is electrically connected to the AgCl layer is provided, and the outside of the cylindrical body may be covered with an insulator (claim 3). .

Further, an internal liquid is housed inside a substantially tubular body, a response film is provided on a part of the tubular body, and an internal electrode is provided in the internal liquid, and an ionic conductivity. A plurality of capillaries having a glass composition having the above are converged on the outer peripheral side of the cylindrical body, and one end side of the condensed capillaries is electrically connected by a conductor, and a lead wire for extracting a reference potential is formed on the conductor. It may be provided with a reference electrode which is connected (claim 4).

In the present invention having the above-mentioned structure, the reference electrode does not require an internal liquid and can be made compact, and can be easily formed by a drawing process (redrawing process) or the like even by an unskilled person. As a result, it is possible to provide a composite electrode for ion concentration measurement that can be easily downsized at low cost.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a composite electrode for measuring ion concentration according to the first embodiment of the present invention (hereinafter referred to as composite electrode).
FIG. 2 is a perspective view schematically showing the structure of D, and FIG. 2 is an explanatory view schematically showing the structure of the composite electrode D. The composite electrode D has a pH
For measuring various ion concentrations such as, for example, a plurality of (several hundred to several thousand) capillaries 1 of SiO ₂ / Na ₂ O (silica-based sodium-based) glass composition having ion conductivity. , 1 ... In a substantially cylindrical shape, for example, in a stem tube 2 made of lead glass, one end of the focused capillaries 1, 1 ... Is electrically connected by a conductor 3, and a lead for extracting a reference potential is formed. A portion of a substantially cylindrical tubular body 6 forming a space for containing an internal liquid 5 between a reference electrode R formed by connecting a wire 4 to the conductor 3 and the outer surface of the stem tube 2. In addition to providing the response film 7, a glass electrode G having an internal electrode 8 provided at a position corresponding to the response film 7 in the internal liquid 5 is provided.

The comparison electrode R is formed as follows. That is, first, SiO having ionic conductivity
₂ / Na ₂ O based glass composition multiples (hundreds to thousands)
The capillary material tube (not shown) is inserted into an insulating glass tube (the stem tube 2) made of lead glass or the like, and the capillary material tube has a straight single-hole through hole of about 10 to 100 μm. 6
A drawing process (redrawing process) is performed at a temperature of 50 to 700 ° C., and this is diced to a predetermined length.

Then, one end side of the diced electrode material (not shown) is molded with a conductive resin, and one end sides of all capillaries 1 are electrically connected by the common conductor 3. In addition, the lead wire 4 for extracting the reference potential is connected to the conductor 3, and the reference electrode R is constituted by this.

The conductor 3 is a eutectic salt of silver halide and silver sulfide. For example, AgCl is 84% and Ag _{2 is 2.}
It can be configured such that S is 16%.

The lead wire 4 is composed of an Ag wire 4a having one end connected to the conductor 3 and a shield wire 4b connected to the other end of the Ag wire.

When the reference electrode R having the above-mentioned structure is immersed in the sample, the sample penetrates into the through hole of the capillary 1 and the gap between the capillaries 1 due to the capillary phenomenon, and the enormous amount of the focused capillary 1 is collected. Na is melted from the liquid contact surface of the sample, and a hydrated layer rich in Na ^{+ with} respect to bulk H ⁺ is formed on the liquid contact surface of the sample inside and outside the capillary 1, and an electromotive force is generated in this hydrated layer. This is taken out to the lead wire 4 as the reference potential, and since the hydration layer is Na ⁺ rich, it is difficult to respond to the pH of the sample, and the variation of the reference potential is extremely small.

On the other hand, since a plurality of capillaries 1 forming the above-mentioned hydration layer are converged to enlarge the liquid contact area, low impedance of the hydration layer is achieved, and moreover,
Since there is no internal liquid, there are no inconveniences associated with liquid clogging, and even if a part of the capillary 1 should be damaged, it can withstand sufficient use and is easy to handle and store, including maintenance, The internal electrode-less reference electrode R having no quality characteristic variation is compactly configured.

In the reference electrode R having the above structure, the capillary 1 is made of SiO ₂ /
Although the Na ₂ O-based glass composition is used, it may be an SiO ₂ / Li-based (silica-based lithium-based) glass composition having ion conductivity. In this case, the reference electrode R is immersed in the sample. In this state, a large amount of the focused capillaries 1, 1 ...
Melts, and a hydrated layer that is rich in Li ^{+ with} respect to bulk H ⁺ is formed on the inner and outer surfaces of the capillary 1 that come into contact with the sample, and an electromotive force is generated in this hydrated layer. Since the hydrated layer is Li ⁺ rich, it is difficult to respond to the pH of the sample, and the fluctuation of the reference potential is extremely small.

Between the outer surface of the stem tube 2 and the tip portion (lower end portion) of the tubular body 6, and between the outer surface of the stem tube 2 and the rear end portion (upper end portion) of the tubular body, the internal liquid is respectively provided. A sealing material 9 is provided so that 5 does not leak. The lead wire 10 connected to the internal electrode 8 is provided in a state where the sealing material 9 provided between the outer surface of the stem tube 2 and the rear end portion (upper end portion) of the tubular body is inserted.

An outer tube 11 made of, for example, stainless is provided outside the glass electrode G, and the outer tube 11 sufficiently increases the mechanical strength of the composite electrode D. An electrode cap 12 is provided on the rear end side (upper end side) of the outer tube 11.

The cylindrical body 6 has a substantially cylindrical lead glass tube 6a whose inner surface is treated with Ag, and a liquid contact surface which comes into contact with the inner solution 5 is treated with AgCl, and a tip side of the lead glass tube 6a ( The response film 7 is composed of a substantially cylindrical pH responsive glass tube fused to the lower end side).

In the composite electrode D having the above-mentioned structure, the reference electrode R does not require an internal liquid and can be made compact, and the above-mentioned stretching process (redrawing process) or the like can be performed even by an unskilled person. The glass electrode G can be easily formed, and only the glass electrode G needs to be provided on the outer peripheral side of the comparatively configured reference electrode R, so that the size can be easily reduced at low cost.
As a result, it is possible to manufacture a composite electrode D having an extremely small size (for example, an outer diameter of 1 mm or less).

In the composite electrode D having the above-mentioned structure, the tip portion 11a of the outer tube 11 is shown in FIG.
As shown in (B) and (C), the tip is projected to the tip side (lower end side) with respect to the comparison electrode R and the glass electrode G, and the tip side becomes sharper. More specifically, by using the outer tube 11 as a stainless steel syringe needle and housing the composite electrode D therein, the composite electrode D can be used in a state of being pierced into the skin of an animal or the like. It will be possible. At this time, the shape of the tip portion 11a of the outer tube 11 may be a shape obtained by obliquely cutting a tubular member as shown in FIG. 3 (A), or as shown in FIG. 3 (B). The taper shape may be tapered toward the tip side. In addition, as shown in FIG.
The outer tube 11 may be provided with a cut portion 11b from the tip side thereof to increase the contact area of the composite electrode D with the sample.

FIG. 4 is an explanatory view schematically showing the structure of the composite electrode D ₂ according to the second embodiment of the present invention. Regarding the members having the same structure as those shown in the first embodiment,
The same reference numerals are given and the description thereof is omitted. The composite electrode D ₂ is
Compared with the composite electrode D of the first embodiment, the glass electrode G
However, it is different in that the internal liquid 5 and the internal electrode 8 are not used and a glass electrode G ₂ is formed in which the lead wire 10 is electrically connected to the cylindrical body 6.

That is, in the glass electrode G ₂ , the response film 7 is provided on a part of the cylindrical body 13 which surrounds the outer peripheral surface of the stem tube 2 of the comparison electrode R, and the inner surface of the cylindrical body 13 is subjected to the silicofluoridation. After that, by reacting with Ag ⁺ ions, an AgCl layer 15 is generated, and further, the AgCl layer 15 is formed.
A lead wire 10 for extracting a measurement potential is electrically connected to the layer 15.

A seal material 9 is provided between the outer surface of the stem tube 2 and the tip portion (lower end portion) of the cylindrical body 13 to prevent the sample from entering into the space.

The cylindrical body 13 has a substantially cylindrical lead glass tube 13a and a tip side (lower end side) of the lead glass tube 13a.
And the response film 14 made up of a substantially cylindrical pH-responsive glass tube fused to the inner surface of the lead glass tube 13a to the inner surface of the response film 14.
The Cl layer 15 is formed.

Since the structure of the reference electrode R, the outer tube 11, the electrode cap 12, etc. is the same as that shown in the first embodiment, the description thereof will be omitted. .

With the composite electrode D _{2 having the} above-mentioned structure, in addition to obtaining the same effect as the composite electrode D of the first embodiment, not only the reference electrode R but also the glass electrode G ₂ has an internal structure. Since no liquid is required, further downsizing can be achieved easily and at low cost.Because it becomes a sensor without a complete internal liquid, the maintainability is dramatically improved and the sample It is possible to almost completely suppress the influence of contamination (contamination).

FIG. 5 is an explanatory view schematically showing the structure of the composite electrode D ₃ according to the third embodiment of the present invention. It should be noted that members having the same structures as those shown in the first and the above-mentioned embodiments are designated by the same reference numerals, and the description thereof will be omitted. Composite electrode D
_In comparison with the composite electrode D ₂ of the second embodiment, ₃ does not have the stem tube 2 of the reference electrode R, and instead of the stem tube 2, surrounds the capillaries 1, 1 ... In addition, the AgCl layer 15 is formed so as to cover not the inner surface of the cylindrical body 13 but the outer surface thereof, and the insulator 1 is formed on the outer side of the AgCl layer 15.
The difference is that 6 is formed.

That is, the cylindrical body 13 serves as the stem tube 2 of the comparison electrode R in the first and second embodiments, and the glass electrode G in the second embodiment.
It is also the member that makes up ₂ .

The insulator 16 is made of AgCl, for example.
The outside of the layer 15 is coated with a resin.

In addition, in addition, the outer tube 11 and the electrode cap 1
Since configurations such as 2 are similar to those shown in the first and second embodiments, repetitive description of those configurations will be omitted.

In the composite electrode D _{3 having the} above-mentioned structure, the same effect as that of the composite electrode D ₂ of the second embodiment can be obtained, and in addition, the stem tube 2 of the reference electrode R is not required. Further downsizing can be achieved easily and at low cost.

FIG. 6 is an explanatory view schematically showing the structure of the composite electrode D ₄ according to the fourth embodiment of the present invention. The members having the same structures as those shown in the first to third embodiments are designated by the same reference numerals and the description thereof will be omitted. Composite electrode D
_In comparison with the composite electrode D of the first embodiment, ₄ is provided with the reference electrode R on the center side and not with the glass electrode G surrounding the reference electrode R. The difference is that the glass electrode G ₃ is on the center side and the reference electrode R ₂ is provided so as to surround the glass electrode G ₃ .

That is, the composite electrode D ₄ accommodates the internal liquid 5 inside the substantially cylindrical tubular body 6, provides the response film 7 on a part of the tubular body 6, and allows the response of the internal liquid 5 to the response. Glass electrode G ₃ provided with an internal electrode 8 at a position corresponding to the film 7
, And a plurality of (hundreds to thousands) capillaries 1, 1 ... Having a glass composition having ionic conductivity are focused on the outer peripheral side of the cylindrical body 6, and one end of the focused capillaries is a conductor 3 And a reference electrode R ₂ formed by connecting a lead wire 4 for extracting a reference potential to the conductor 3 while being electrically connected to each other.

The plurality of capillaries 1, 1 ... Are provided in a state of being converged between the cylindrical body 6 and the stem tube 2 arranged on the outer peripheral side thereof with a space.

Sealing materials 9 for preventing the internal liquid 5 from leaking out are provided on the front end side (lower end side) and the rear end side (upper end side) of the cylindrical body 6, respectively.

The outer tube 11 is provided outside the stem tube 2.
The electrode cap 12 is provided on the rear end side (upper end side) of the outer tube 11.

Since the other constructions are the same as those shown in the first to third embodiments, the description of those constructions will be omitted.

With the composite electrode D _{4 having the} above structure, the same effect as that of the composite electrode D of the first embodiment can be obtained.

[0041]

According to the present invention having the above structure, it is possible to provide a composite electrode for measuring ion concentration, which can be easily downsized at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a configuration of a composite electrode for measuring ion concentration according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram schematically showing the configuration of the above embodiment.

FIG. 3A is an explanatory view schematically showing the configuration of a modified example of the outer tube in the above embodiment, and FIG. 3B is a schematic diagram of the configuration of another modified example of the outer tube in the above embodiment. Explanatory diagram showing
(C) is an explanatory view showing roughly the composition of other modification of the outer pipe in the above-mentioned example.

FIG. 4 is an explanatory view schematically showing the structure of a composite electrode for ion concentration measurement according to a second embodiment of the present invention.

FIG. 5 is an explanatory view schematically showing the structure of a composite electrode for ion concentration measurement according to a third embodiment of the present invention.

FIG. 6 is an explanatory view schematically showing the structure of a composite electrode for measuring ion concentration according to a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Capillary, 2 ... Stem tube, 3 ... Conductor, 4 ... Lead wire, 5 ... Internal liquid, 6 ... Cylindrical body, 7 ... Response film, 8 ... Internal electrode, D ... Composite electrode for ion concentration measurement, G ... Glass electrode, R ... Reference electrode.

Claims (4)

[Claims] 1. A plurality of capillaries having a glass composition having ion conductivity are focused in a substantially cylindrical stem tube, and one end of the focused capillaries is electrically connected by a conductor, and a reference potential is taken out. A reference electrode formed by connecting the lead wire of the above-mentioned conductor to the conductor and a stem forming a space for accommodating an internal liquid between the stem tube, and a response film provided on a part of the cylindrical body. A composite electrode for measuring ion concentration, comprising: a glass electrode having an internal electrode provided on the inner surface thereof. 2. A plurality of capillaries having a glass composition having ion conductivity are focused in a substantially cylindrical stem tube, and one end of the focused capillaries is electrically connected by a conductor, and a reference potential is taken out. A reference electrode having the lead wire connected to the conductor, and a response film provided on a part of a cylindrical body surrounding the outer peripheral surface of the stem tube, and after the inner surface of the cylindrical body is subjected to fluoridation with Ag,
Generate an AgCl layer by reacting with ⁺ ions,
Furthermore, a composite electrode for ion concentration measurement, comprising a glass electrode in which a lead wire for extracting a measurement potential is electrically connected to the AgCl layer. 3. A plurality of capillaries having a glass composition having ionic conductivity are focused, one end side of the focused capillaries is electrically connected by a conductor, and a lead wire for extracting a reference potential is provided in the conductor. And a reference electrode connected to the capillary, and a response film provided on a part of a cylinder surrounding the capillary, and the outer surface of the cylinder is subjected to a C-fluoridation and then reacted with Ag ⁺ ions.
A gCl layer is formed, and a glass electrode in which a lead wire for measuring potential extraction is electrically connected to the AgCl layer is further provided, and the outside of the cylindrical body is covered with an insulator. A composite electrode for measuring ion concentration. 4. A glass electrode, wherein an internal liquid is contained inside a substantially tubular body, a response film is provided on a part of the tubular body, and an internal electrode is provided in the internal liquid; and an ionic conductivity. A plurality of capillaries having a glass composition having the above are converged on the outer peripheral side of the cylindrical body, and one end side of the condensed capillaries is electrically connected by a conductor, and a lead wire for extracting a reference potential is formed on the conductor. A composite electrode for measuring ion concentration, comprising a reference electrode connected to the composite electrode.