JPS63246652A - Ion activity measuring apparatus - Google Patents

Abstract

PURPOSE:To achieve a measurement with a better reproducibility, by providing a sheet-like porous member having a water inpermeable area adjacent to a water-permeable area between a path and the surface of an electrode to keep constant a range in which a liquid touches the surface of the electrode. CONSTITUTION:When a sample liquid and a reference liquid are supplied to a porous member 16 at an opening 12 separately, they are connected with a bridge 19. These liquids are transferred to an ion selection electrode through a path 14 by way of the porous member 16. A sheet-like porous member 24 having a water impermeable area 241 adjacent to a water-permeable area 242 is made to fill between a horizontal path 14 and a working surface of the ion selection electrode, the liquids are transferred through paths 242a-242c of the porous member 24 and as it arrives right below the ion selection electrode, the porous member expands to contact working surfaces of the ion selection electrodes 11a-11c. With the sample liquid and reference liquid, a potential difference is generated in ion selection couples and measured.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention utilizes botensiometry to measure the activity (or degree) of specific ions in aqueous liquids, particularly biological fluids (blood, urine, saliva, etc.). This invention relates to an ion activity measuring instrument for quantitative analysis.

[Background of the invention] Using the droplet volume of liquids (tap water, river water, sewage, industrial wastewater, etc.) and biological body fluids (blood such as whole blood, blood leaves, serum, urine, saliva, etc.), Instruments for measuring the activity of specific ions using sheet-like ion-selective electrodes are already known.

That is, a reference liquid and a test liquid are applied to the surface of each ion-selective layer of a pair of sheet-like ion-selective electrodes each having an ion-selective layer on the top, which are electrically separated from each other, and the two liquids are connected to each other by a bridge. The ionic activity of the test liquid is measured by measuring the potential difference of the ion selective electrode in an electrically conductive state.

An example of such an ion activity measuring instrument is JP-A-52-1
Publication No. 42588 (US 405:1381) (U
S stands for U.S. patent), Japanese Patent Application Laid-open No. 56-6148 (
US Pat. No. 4,273,638), Japanese Unexamined Patent Publication No. 58-211648 (US Pat. No. 44:+7970), etc.

These ion activity measurement instruments basically have a pair of sheet-shaped ion-selective electrodes arranged with the ion-selective layer facing upward, and a liquid spotting hole (covered with the standard solution) in the frame that covers the ion-selective electrodes. The reference solution and the test solution are applied from above onto each ion-selective layer using a pipette or the like through the liquid spotting holes, and both ion-selective electrodes The ionic activity is measured by measuring the potential generated between the two.

Among the above examples, the ion activity measuring instrument disclosed in Japanese Patent Application Laid-Open No. 58-211648 has - ion activity ff1J11
By incorporating a plurality of pairs of ion-selective electrodes into a measuring device, the activities of a plurality of types of ions can be measured by applying a reference liquid and a test liquid once each. In the ion activity measurement device disclosed in this publication, a sheet-like ion selection electrode was arranged so that the ion selection layer faced upward. Sheet-shaped ion-selective electrodes generally use an electrically insulating sheet as a support, with a conductive layer on the surface.
A sparsely soluble salt layer, a soluble salt layer (sometimes omitted), and an ion selective layer are laminated in this order. and the exposed portion of the conductive layer (or exposed portion as required)
is used as an electrical connection area, and the potential difference measurement is performed by contacting the terminal of the potentiometric measuring device to that area. Therefore, in the arrangement of the sheet-like ion-selective electrode in which the ion-selective layer faces upward as disclosed in the above-mentioned publication, it is avoided that the terminal for potential difference measurement and the connection connected thereto be located above the sheet-like electrode. I can't. Since the potential difference to be measured is minute, it is desirable to install a preamplifier (head amplifier) near the terminals, so this also needs to be installed near and above the sheet-like electrode. These electrical components occupy space above the ion activity measuring instrument. On the other hand, since the sample solution and reference solution are supplied from above the ion activity measurement device using a pipette, etc., a certain amount of space is required above the ion activity measurement device, and the electrical components are must be located so as not to interfere with the operation of the In an automatic analyzer that continuously performs a large number of measurements by automatically feeding and renewing ion activity measuring instruments, a problem has arisen in that the size of the apparatus has to be increased in order to meet such demands.

On the other hand, if the electrical connection area of the ion activity measurement device is exposed upward, this area or its vicinity will be contaminated by the sample and reference solutions supplied from above.
Failure of continuity or insulation may occur, resulting in potential difference measurement errors.

In addition, when measuring ion activity, the area of contact between the liquid to be measured (sample liquid and reference liquid) and the active surface of the ion-selective electrode (the surface of the ion-selective layer) must be constant within a certain tolerance range, or the measurement accuracy However, in the arrangement where the measurement liquid is supplied to the top surface of the sheet-like ion-selective electrode,
In order to confine the liquid to a certain area on the sheet electrode, a means for reliably closing the area, such as a mask with holes, is required. When mass-producing ion activity measuring instruments, it is a complicated process to manufacture a mask with holes of precise dimensions and attach it to the sheet electrode in close contact, which is very inefficient.

[Technical Problems to be Solved] The present invention solves the above problem in the ion activation fit Jll fixed device disclosed in Japanese Patent Application Laid-Open No. 58-211648, in which a sheet-like ion selection electrode is arranged so that the ion selection layer faces upward. The purpose is to solve all three drawbacks: space occupancy above the electrical connection parts, contamination of the electrical connection area, and the need for a mask to be in close contact with the electrode surface.

[Means for Solving Technical Problems] The present invention achieves the above object by providing at least one pair of sheet-shaped ion selection electrodes that are electrically isolated from each other and that selectively generate a potential difference with respect to specific ions.

a liquid supply unit for supplying a test liquid to the working surface of one electrode of the pair and a reference liquid to the working surface of the other electrode of the pair, and the test liquid applied to each electrode; a bridge for electrically conducting the reference liquids to each other; the sheet-shaped ion-selective electrode is disposed with a working surface facing downward; at least a horizontal passage located below the surface for horizontally moving the externally applied test liquid or reference liquid directly below the working surface of each ion-selective electrode; A measuring device for measuring the activity of ions, the sheet-like porous member having a water-impermeable region adjacent to a water-permeable region between the horizontal channel and the working surface of the ion-selective electrode. each of said water-permeable regions of said porous member or said raising passageway for raising said test liquid or reference liquid from a horizontal passageway to a position at the working surface of each ion-selective AI electrode. It is configured.

This was achieved by an ion activity measurement device characterized in that each water permeable region is adjacent to the water impermeable region so as to be entirely included in the working surface of the corresponding ion selective electrode.

The object of the present invention further includes a planar water-impermeable partition wall between the sheet-like porous member and the ion-selective electrode, and the partition wall is arranged between the porous member and the working surface of the ion-selective electrode. The thickness of the partition wall is such that the sample liquid and the reference liquid do not cause capillary action along the wall surface around the opening. preferably achieved.

One practically preferred embodiment of the ion activity measuring instrument of the present invention is as follows.

an upper frame body having a pair of openings through which a test liquid and a reference liquid can be supplied from the outside to the water flow path; a pair of openings communicating with the pair of openings; and the partition wall having the openings. and a lower frame having a recessed portion forming the horizontal passage, wherein the at least one pair of ion selection electrodes are housed in the upper frame, and the sheet-like porous member is connected to the partition wall and the lower frame. The ion activity measuring device is housed between the body.

[Details of the structure of the invention] Sheet-shaped ion selective electrodes that selectively generate a potential for specific ions are disclosed in, for example, JP-A-58-156848, JP-A-58-19:1449, and JP-A-58. -211
No. 648, JP-A-60-237351, JP-A-60-
217:152, JP-A-61-7460, JP-A-6
1-7461 and JP-A-61-7462, etc., and are well known to those skilled in the art. That is, the ion-selective electrode includes an electrically insulating material, a support, a conductive metal layer (e.g., a silver layer), a water-insoluble salt of the metal (e.g., silver chloride) layer,
An anion and a cation common to the anion of the water-insoluble salt (
It has a basic structure in which an electrolyte layer containing a water-soluble salt (eg, potassium chloride, sodium chloride) (eg, potassium ion, sodium ion) and an ion-selective membrane layer are integrated in this order.

In actual ion activity measurement, two ion-selective electrodes (half-cells) having the basic configuration as described above (preferably those with the same configuration) are used as a pair, and a sample solution and a reference solution are placed in the ion-selective layer of each electrode. After a certain period of time after spotting, the potential difference that occurs between the conductive metal layers of the two electrodes is measured via a water-bearing bridge that electrically connects the two liquids. From the calibration curve, calculate the ionic activity of the electrolyte contained in the sample solution. The pair of ion selective electrodes must be electrically isolated from each other except for the bridge.

Particularly useful are pairs of ion-selective electrodes constructed integrally on a common sheet-like support and electrically isolated by a scratch groove, such as that disclosed in JP-A-58-156848.

a metal layer formed on a common sheet-like support;
In order to provide a scratch groove in the hardly soluble metal salt layer (and in some cases, the ion selective membrane layer), Japanese Patent Application Laid-Open No. 60-24355
The method described in this issue is useful.

The bridge for electrically conducting the test liquid and reference liquid applied to each pair of electrodes is preferably a porous bridge that utilizes capillary phenomenon, and the porous bridge is made of natural fiber or synthetic polymer fiber (for example, Preferably, the material is made of nylon fiber) or polyester fiber (eg, polyethylene terephthalate fiber).

One feature of the ion activity M measurement device of the present invention is that the sheet-like ion selective electrode is arranged with the working surface facing downward, and the measuring liquid is applied to the working surface from a liquid measuring container such as a pipette under a gravitational field. Since it is difficult to supply the test liquid or reference liquid directly below the working surface of the ion-selective electrode, the test liquid or reference liquid applied from above from the outside is placed directly below the working surface of the ion-selective electrode in a horizontal direction. Is it necessary to provide a liquid supply with a horizontal passage for moving the liquid?

The horizontal passage is usually formed of a trough-like or partially trough-like cylindrical member made of a liquid-impermeable, impermeable, electrically insulating material at least on the surface.

One of the features of the ion activity measuring device of the present invention is that a sheet-like porous member is filled between the horizontal passage and the working surface of the ion selective electrode. This sheet-like porous member can be appropriately selected from (porous) materials having continuous fine gaps capable of producing a capillary phenomenon. As the above-mentioned porous material, pharmacopoeial bandages, pharmacopoeia gauze, linen kaya, cold weather, silk, filter paper, synthetic polymer fibers (e.g., polyester fibers), etc. may be used, but hemolysis of the blood sample may occur. It is particularly desirable to use a nonwoven fabric made of long-fiber cellulose because it is difficult to tear, easy to cut and mold, and quick to spread liquid. The nonwoven fabric made of long fiber cellulose is preferably a cellulose spunbond nonwoven fabric substantially free of binder, and particularly preferably one made of long fibers made from cotton linters. For example, a nonwoven fabric manufactured by a spunbond method from a spinning solution obtained by dissolving cotton linters in Schweitzer liquid is preferably used.

The thickness is preferably between 1004 m and 500 m.

The sheet-like porous material described above is used to construct a measuring instrument (the configuration of the measuring instrument will be described later using drawings).
Cut and use as appropriate.

In the ion activity measuring device of the present invention, a water-impermeable region is partially formed in the porous member. and,
in said porous member; ii or more water permeable regions separated by ice water impermeable regions permit said test or reference liquid to rise from the horizontal passageway to the working surface of each ion selective electrode; Each of the two or more ascending passages constitutes two or more ascending passages for

There are various methods for partially forming a water-impermeable region in a porous member.

First, there is a method of coating a part of the surface of a sheet-like porous member with a water-impermeable substance. As the above-mentioned covering means,
Various known means (including lamination) can be used. Note that adhesive or adhesive tape can also be used as the covering means. A double-sided thermal adhesive tape is particularly preferred as the covering means.

Second, it is also possible to use a method in which a portion of the sheet-like porous member contains a water-impermeable substance. Specifically, methods include partially applying a liquid water-impermeable substance or a solution of a water-impermeable substance to a porous member and allowing it to penetrate, or applying a water-impermeable substance that is solid or non-flowing at room temperature. There are various methods such as heating to melt or fluidize the material and partially infiltrate the porous member.

Third, when using thermoplastic synthetic polymer fibers such as polyester fibers as the porous member, the porous member is partially heated and molded at an appropriate temperature that will cause it to lose its porosity (water permeability). A method can be used.

Fourthly, when the porous member is housed in the ion activity measurement device, pressure may be applied to a part of the porous member to cause the porosity (water permeability) of that part to be lost. .

Among the methods described above, the first method and the second method are particularly preferred. As water-impermeable substances used in these methods, any substance can be used without particular restrictions as long as it does not interfere with the measurement of ion activity, specifically, it does not release or absorb the ions to be measured. . Therefore, the water-impermeable material can be selected from various types of materials and used depending on the specific method described above. Hot-melt adhesives, generally known as hot-melt agents, have the advantage of being easily liquefied by heating and penetrating into porous members to partially form water-impermeable regions. It can be particularly preferably used as an impermeable substance. In other words, if a thermal adhesive tape or the like having hot melt adhesive on one or both sides is placed on a porous member and heated and pressed, the hot melt adhesive will penetrate only into the area that overlapped with the thermal adhesive tape, making it porous. The material is impermeable to water. When using double-sided adhesive tape, the part that comes into direct contact with the heat source may be heated and pressurized with the release paper attached. After the hot melt adhesive hardens, it strongly bonds to the surface or interior of the porous member.

A method of partially forming a water-impermeable region in a porous member using a thermal adhesive tape having a hot melt adhesive on one or both sides will be described below with reference to one drawing.

Figure 1D is shown in Figures 1 and 2, which will be described later! FIG. 3 is a schematic cross-sectional view showing a process (heating and pressurizing process) for forming a water-impermeable region in a porous member used in an island shape.

As shown in FIG. 1D, a water-impermeable bulkhead 20, a porous member 24 and a thermal adhesive tape 25 are placed on a flat platform 27.
110 times, and then iron 2 as a heat source from above.
6, a water-impermeable region can be formed in the porous member. The thermal adhesive tape 25 includes a release paper 251, an adhesive layer 252, a support 253, and an adhesive layer 254.
and release paper 255 (not shown) are sequentially laminated. Then, the thermal adhesive tape 25 is attached to a release paper 25.
5 is peeled off and then superimposed on the porous member 24.

FIG. 1E is a schematic cross-sectional view showing a porous member in which a water-impermeable region is partially formed by the treatment shown in FIG. 1D.

As shown in FIG. 1E, the hot melt adhesive permeates only the portion of the porous member 24 that overlaps with the thermal adhesive tape 25, forming a water impermeable region 241.

The water-impermeable region 241 is maintained in the compressed shape during the heating and pressurizing process by the hot melt adhesive. A region of the porous member 24 into which the hot melt adhesive does not permeate corresponds to a water permeable region 242 . This water permeable region 242 returns to its original thickness when the pressure is removed.

FIG. 3D shows a process (heating,
FIG.

As shown in FIG. 3D, a water-impermeable partition wall 40, a thermal adhesive tape 45, and a porous member 44 are sequentially stacked on a flat table 37, and an iron 46 is pressed as a heating source from above. , a water-impermeable region can be formed in the porous member. The thermal adhesive tape 45 has an adhesive layer 452
, a support 453, and an adhesive layer 454 are sequentially laminated.

FIG. 3E is a schematic cross-sectional view showing a porous member in which a water-impermeable region is partially formed by the treatment shown in FIG. 3D.

As shown in FIG. 3E, the hot melt adhesive permeates only the portion of the porous member 44 that overlaps with the thermal adhesive tape 45, forming a water-impermeable region 441.

A region of the porous member 44 into which the hot melt adhesive does not permeate corresponds to a water permeable region 442 .

Due to the configuration of the porous member as described above, the ion activity measurement device of the present invention has a passage (hereinafter abbreviated as the rising passage) for raising the liquid from the horizontal passage to the working surface of each ion selective electrode. It can be constructed in a sheet-like porous member. Note that all the ascending passages for each ion selective electrode may be provided in one sheet-like porous member, but if there is a possibility that the test liquid and reference liquid will come into contact within the porous member, a sheet-like porous member may be provided. It is preferable to use two porous members such that two or more rising passages for the test liquid are formed in one of the porous members and two or more rising passages for the reference liquid are formed in the other porous member.

As a result of the above, the ion activity measurement device of the present invention can provide all the necessary rising passages for each ion selection electrode in one or two sheet-like porous members.
It has the advantage of being easy to manufacture.

Hereinafter, specific examples of the ion activity measuring instrument of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an example of the ion activity measuring instrument of the present invention. FIG. 1A is an elevational sectional view taken along line I-I of the ion activity measuring device shown in FIG. 1, and FIG. 1B is a bottom view of the ion activity measuring device shown in FIG. , and FIG. 1c is an enlarged view of the circled portion X of FIG. 1A. FIG. 2 is a diagram separately showing each member constituting the ion activity training device shown in FIG. 1.

The activity measuring device of the embodiment shown in these figures has an upper frame 1
B, 3 pairs of ion electrodes (pairs) lla housed in the upper frame
, llb, llc, a lower frame 21, a water-impermeable partition wall 20 provided between the upper frame and the lower frame, and a bridge 19.

Three pairs of sheet-like ion electrodes (pairs) 11a, llb, ll
They are respectively accommodated and fixed in grooves provided in an upper frame 18 made of a water-impermeable, electrically insulating material such as polystyrene. This upper frame body 18 is provided with two openings 12 for applying the sample liquid and the reference liquid, respectively, and the sample liquid and the reference liquid are electrically connected across these openings. bridge (e.g. consisting of polyethylene terephthalate!A fiber yarn) 19
Or is provided. 3 pairs of sheet-like selection electrodes (pairs)
a, llb, llc are respectively Japanese Patent Application Laid-Open No. 58-1568.
It consists of a combination of ion-selective electrodes of the same configuration that are electrically isolated from each other by the method of No. 48, and the sheet-like ion-selective electrodes constituting each pair are as shown in FIG. 1c. A silver layer 112 and a silver chloride layer 113 are formed on a support 111 made of an electrically insulating polymer film.
, an electrolyte layer 114, and an ion-selective membrane layer 115 are laminated, and the sheet-like ion-selective electrode constructed in this way has the ion-selective layer 1 in the measuring instrument.
It is placed with the 15 side facing down.

A water-impermeable partition 20, for example made of polyethylene, is provided between the upper frame and the lower frame. This water-impermeable partition 20 has four pairs of openings 13.15a, 15b, 1
5c is provided. Is there any particular restriction on the shape of these openings?
, 15c) are preferably of such shape that, when projected onto the working surface of the corresponding ion selective electrode, they are all contained within the working surface.

The water-impermeable partition wall 20 is coated with an adhesive (preferably a pressure-sensitive adhesive or a heat-sensitive adhesive) on the L surface of the lower frame 21 or the lower surface of the upper frame 18, or on both.

A sheet adhesive may also be used. ), heat fusion, mechanical fixation, or the like.

Between the water-impermeable partition wall 20 and the lower frame 21, there is a sheet-like porous member (hereinafter referred to as a porous member for ascending passage) 24 in which a water-impermeable region 241 is partially formed. Filled. In the embodiment shown in FIGS. 1 and 2, the water-impermeable region 241 is formed by pasting a thermal adhesive tape 25 on the lower surface of the porous member for the ascending passage, and penetrating the porous member with a hot melt adhesive. It is formed by In addition, as shown in FIG. 1C, the water impermeable region 2
The water-permeable region 242b separated by 41 is adjacent to the water-impermeable region 241 such that it is entirely contained by the working surface of the corresponding ion-selective electrode when projected onto the working surface. and.

Each water permeable region 242a, 242b, 242c constitutes a rising passage.

A lower frame made of thermoplastic resin (for example, polystyrene) is disposed below the water-impermeable partition wall 20 . A horizontal liquid passage is formed in the lower frame 21 as a groove 14. A band-shaped porous member (hereinafter referred to as a horizontal passage porous member) 16 is accommodated in this groove 14 . The material for the horizontal passage porous member may be the same as the above-mentioned ascending passage porous member (sheet-like porous member).

As can be understood from FIG. 1A, the liquid supply section for applying the sample liquid and the reference liquid to the working surface of the ion-selective electrode includes an opening 12 provided in the upper frame, and an opening 12 for supplying the liquid from the ion-selective electrode to the working surface of the ion-selective electrode. an opening 13 for reception in a lower horizontal channel; a horizontal channel 14 for moving the liquid horizontally to just below the ion-selective electrode; and a horizontal channel 14 for moving the liquid horizontally to just below the ion-selective electrode; It is composed of lifting passages 242a, 242b, and 242C for lifting. The horizontal passage 14 is provided in the lower frame body.
4, and a horizontal passage porous member 16 is housed therein. And the rising passages 242a, 242b, 2
42C is formed by the water permeable region of the above-mentioned ascending passage porous member 24.

This rising passage porous member 24 is a water-impermeable partition wall 20
The openings 15a, 15b, and 15c are configured to protrude from each opening toward the ion selection electrode. The distance between the upper end of the rising passage porous member 24 protruding from each opening and the lower surface of the sheet-like ion electrode is such that when the sample liquid and the reference liquid are supplied to the rising passage porous member, the liquid selects ions. It is necessary to set the distance so that it can come into contact with the lower surface of the electrode. The ascending passage porous member 24 protruding from each opening may be in contact with the lower surface of the sheet-like ion selection electrode, but until the sample liquid and reference liquid are supplied to the porous member, the sheet-like ion selection electrode It is preferable to avoid contact with the lower surface of the electrode for preservation of the electrode. In order to achieve this positional relationship before and after supplying the liquid, the porous member absorbs the sample liquid and reference liquid and expands (for example, 1.5
(up to several tens of times) is desirable.

Ion selection electrode pairs 11a, ll are provided at both ends of the lower frame.
b, llc, each electrical connection area 22a, 22b, 22
a cutout portion 23a for exposing the portion c downward;
23b and 23c are provided. Although the notch portion may be provided individually for each ion-selective electrode pair in this way,
It can also be provided commonly to a plurality of or all of the ion selection electrodes.

The operation of the ion activity measuring device of the embodiment shown in FIG. 1 will be explained below. Using a pipette, a dispenser, etc., the sample solution and the reference solution are respectively passed from the opening 12 provided in the upper frame through the opening 13 into the horizontal passage hole accommodated in the groove 14 provided in the lower frame. It is supplied to the sexual member 16. A bridge 19 provided across the opening electrically connects the sample liquid and the reference liquid. Liquid 6 is a porous member 16 for horizontal passage.
The ion-selective electrode is transported through the horizontal passageway 14 directly below the ion-selective electrode. Further, the 6 liquids are supplied to the rising passages 242a, 242b, 242 provided in the porous member 24 for rising passages.
C to the working surface of the ion-selective electrode. When the liquid reaches directly below the ion selection electrodes in the rising passages 242a, 242b, 242c, the porous member that has absorbed the liquid expands, and the working surface of each ion selection electrode 11a, llb, llc, that is, the ion selection a layer. Comes into contact with the surface. In this way, a potential difference is generated between each ion-selective electrode pair by the sample solution and the reference solution, and this potential difference is applied to the ion-selective electrode pair.
It can be measured by potentiometers connected to M and negative connection regions 22a, 22b, and 22c provided at 1a, llb, and llc, respectively. The water-impermeable partition wall 20 is thick enough to prevent the sample liquid and reference liquid from causing capillary action along the wall surfaces around the openings (15a, 15b, 15c), so the liquid is spread in a sheet-like manner. Because the liquid is supplied to the electrode surface only through a porous member that is in contact with the lower surface of the ion-selective electrode or close enough to produce capillary action, the range in which the liquid contacts the electrode surface is constant, and the reproducibility of measurements is improved. good.

FIG. 3 is a perspective view showing another example of the ion activity measuring instrument of the present invention. Figure 3A is a three-dimensional sectional view taken along line 1'-I' of the ion activity measuring instrument shown in Figure 3, and Figure 3B is a bottom view of the ion activity measuring instrument shown in Figure 3. Yes, and Figure 3C is the circled area X in Figure 3A.
′ is an enlarged view. FIG. 4 is a diagram separately showing each member constituting the ion activity measuring device shown in FIG. 3. , three pairs of ion-selective electrodes (
The main parts thereof include the pair) 31a, 31b, and 31c, a lower frame 41, a water-impermeable partition wall 40 provided between the upper frame and the lower frame, and a bridge 39.

Three pairs of sheet-like ion selective electrodes (pairs) 31a, 31b,
31c are accommodated and fixed in grooves provided in the one-part frame 38 made of polystyrene acid. This upper frame 3
8 is provided with two openings 32 for applying a sample liquid and a reference liquid respectively, and a bridge is provided across these openings for electrically conducting the sample liquid and the reference liquid. 39 (for example made of polyethylene terephthalate fiber yarn) is provided. The three pairs of sheet-like ion-selective electrodes 31a, 31b, and 31c each consist of a combination of ion-selective electrodes with the same configuration that are electrically isolated from each other by the method of JP-A-58-156848. The sheet-like ion-selective electrodes constituting the pair are sheet-like ion-selective electrode (pair) lla,
As shown in FIG. 3C, the tJ1 layer 112 . Silver chloride layer 113, electrolyte layer 114
, and each layer of the ion selective membrane layer 115,! ! ie configured. The sheet-like ion-selective electrode is placed in the measuring instrument with the surface of the ion-selective membrane layer 115 facing downward.

A water-impermeable partition wall 40, made of polyethylene, for example, is provided between the upper frame and the lower frame. This water-impermeable partition wall 40 has four pairs of openings 33.35a, 35b, 3.
5c is provided. The thickness of the water-impermeable partition wall 40 is
The sample liquid and reference liquid are thick enough not to cause capillary action along the walls around the openings (35a, 35b, 35c), so the liquid does not come into contact with the bottom surface of the sheet-shaped ion-selective electrode or cause capillary action. Since the liquid is supplied to the electrode surface only through the porous member that is close to the limit distance, the area in which the liquid contacts the electrode surface is constant.

Good reproducibility of measurements.

The water-impermeable partition wall 40 is formed by applying an adhesive (preferably a pressure-sensitive adhesive or a heat-sensitive adhesive; a sheet-like adhesive may also be used), a heat melt It is preferable that they be joined by bonding, mechanical engagement, or the like.

A rising passage porous member 44 in which a water-impermeable region 441 is partially formed is filled between the water-impermeable partition wall 20 and the lower frame 21 . In the embodiment shown in FIGS. 3 and 4, the water-impermeable region 441 is formed by pasting a thermal adhesive tape 45 on the upper surface of the porous member for the ascending passage, and bonding the hot melt adhesive to the upper surface of the porous member for the ascending passage. It is formed by infiltrating the member. Note that, as shown in FIG. 3C, the water-permeable region 442b separated by the water-impermeable region 441 is such that the water-permeable region 442b is entirely included in the working surface of the corresponding ion-selective electrode when projected onto the working surface. Adjacent to water impermeable region 441 . Each of the water permeable regions 442a, 442b, and 442c constitutes an ascending passage.

A lower frame 41 made of thermoplastic resin (for example, polystyrene) is provided below the water-impermeable partition 40, and a horizontal liquid passage is formed in the lower frame 41 as a groove 34.

A strip-shaped horizontal passage porous member 36 is accommodated in this groove 34 .

As can be understood from FIG. 3A, the liquid supply section for applying the sample liquid and the reference liquid to the working surface of the ion selective electrode includes an opening 32 provided in the upper frame, and a liquid supply section for applying the sample liquid and the reference liquid to the working surface of the ion selective electrode. an opening 33 for receiving the lower horizontal passageway, a horizontal passageway 34 for moving the liquid horizontally to just below the ion-selective electrodes, and a horizontal passageway 34 for transporting the liquid horizontally to the working surface of each ion-selective electrode, i.e. to the surface of the ion-selective membrane layer. It is composed of lifting passages 442a, 442b, and 442C for lifting. The horizontal passage 34 is a groove 34 provided in the lower frame body.
The horizontal passage porous member 36 is housed therein. And rising passages 442a, 442b, 442
c is formed by the water permeable region of the rising porous member 44 described above.

This upper boundary passage porous member 44 is a water-impermeable partition wall 40
The openings 35a, 3Sb, and 35c are configured to protrude from each opening toward the ion selection electrode. Regarding the thickness of this water-impermeable partition wall 40, the same principles as in the embodiment shown in FIG. 1 apply.

Ion selection electrode pairs 31a, 31 are provided at both ends of the lower frame.
b, 31c, each electrical connection area 42a, 42b, 42
A cutout portion 43 is provided to expose the portion c downward. The cutout portion 43 may be provided in common for a plurality of or all of the ion selection electrodes as in this example, or may be provided individually for each ion selection electrode.

The operation of the ion activity measuring instrument of the embodiment shown in FIG. 3 will be explained below. Using a pipette, a dispenser, etc., the sample solution and the reference solution are passed from the opening 32 provided in the upper frame to the horizontal passage hole accommodated in the groove 34 provided in the lower frame through the opening 33. The sexual member 36 is supplied. A bridge 39 placed across the opening provides a commercial connection between the sample and reference fluids. 6 liquid is porous member 3 for horizontal passage
6 in the horizontal passageway 34 directly below the ion selection electrode. Further, the 6 liquids are supplied to the rising passages 442a, 442b, 44 provided in the porous member 44 for rising passages.
2c to the working surface of the ion selective electrode. When the liquid reached the inside of the rising passages 442a, 442b, 442c directly below the ion selection electrode, the liquid was absorbed. The porous member expands into contact with the working surface of each ion-selective electrode, ie, the surface of the ion-selective membrane layer. In this way, a potential difference is generated between each ion-selective electrode pair by the sample solution and the reference solution.
This potential difference is the ion selection electrode pair 31a, 31b, 31c.
electrical connection areas 42a, 42b, 4 provided respectively in
It is measured by a potentiometer connected to 2c.

In both the embodiment of FIG. 1 and the embodiment of FIG. 3, the upper frame and the lower frame may be joined via a water-impermeable partition wall, or may be directly joined to each other. In the case of directly joining the frame, the same method as in the case of joining the frame to the water-impermeable partition wall can be used. As long as it is possible to incorporate the porous member for the ascending passage and the sheet-like ion selection single pole, it is not necessary for the upper frame, the lower frame, and the water-impermeable partition wall to be constructed in one piece. .

It can be constructed from a plurality of members.

Is it possible to manufacture the upper frame, the water-impermeable intermediate member, and the lower frame from a desired shape-retaining material? Preferably, it is formed from a plastic material. For example, known methods such as a method of placing a plastic material in a desired mold and molding it, a drawing method using a sheet-shaped plastic material, etc. can be used.

The liquid application opening 12 can be surrounded by a low protrusion to prevent the liquid to be dispensed from overflowing to the outside of the opening, and can also be used as a guide to easily and reliably apply the liquid.

The bridge is a membrane filter, cancer paper, and JP-A-55-2.
It may also be a bridge made of filter paper laminated with a single layer of hydrophobic organic polymer on both sides as described in Japanese Patent No. 0499.

When measuring the ion activity of a sample liquid using the ion activity measuring instrument of the present invention, the measuring liquid receiving port of the ion activity measuring instrument (for example, opening 12 in FIG. 1, opening 32 in FIG. 3)
It is desirable to supply certain counterfeit sample solutions and reference solutions using pipettes, dispensing bases, etc. However, the accuracy does not need to be very high (for example, ±25%).

Examples of Pibeut include JP-A-61-1731:11, JP-A-61-198036, and JP-A-60-2747.
10, JP-A No. 60-279840, etc. are suitable.

[Brief explanation of drawings]

Figures 1 and 3 are perspective views showing embodiments of the present invention, Figures 1A and 3A are sectional views, Figures 1B and 3B are bottom views, and Figures ic and 3C are The enlarged cross-sectional view, FIG. 1D, FIG. 1E, FIG. 3D, and FIG. 3E are schematic cross-sectional views each showing a step of providing a water-impermeable region. 2 and 4 are exploded perspective views of the ion activity measuring instrument. 11a, llb, llc: ion selection electrodes 31a, 31
b, 31c: ion selective electrode 111.311: supporter 112.312: silver layer 113.313: silver chloride layer 114.314: electrolyte layer 115.315: ion selective 8 layer 12.32: liquid application opening 13 .33: Liquid descending passage 14.34: Liquid horizontal passage 15a, 15b, 15c: Ascending passage opening 35a, 35
b, 35c: opening for rising passage 16.36: porous member for horizontal passage 18.38 two upper frames 19.39 nib bridge 20.40: water-impermeable partition wall 21.41: lower frame 42a, 42b, 42c : Electrical connection areas 23a, 23b, 23c, 43 of ion selection electrode: Notches 24.44:
Porous member for ascending passage 241.441: - Water impermeable region of porous member for ascending passage 242.442: Water permeable region of porous member for ascending passage (ascending passage) 25.45: f! % Adhesive tape 26.46: Iron 27.47: Stand Applicant: Fuji Photo Film Co., Ltd. Representative Patent attorney: Yasushi Yanagawa Younger brother 1, 91!3 Figure 3 Figure 3A

Claims (1)

[Scope of Claims] 1. At least one pair of sheet-shaped ion-selective electrodes that are electrically isolated from each other and that selectively generate a potential difference with respect to specific ions; a test liquid is disposed on the working surface of one electrode of the pair; , a liquid supply unit for supplying a reference liquid to the working surface of the other electrode of the pair, and a bridge for electrically conducting the test liquid and the reference liquid applied to each electrode with each other. , the sheet-like ion selective electrode is arranged such that its working surface faces downward, and the liquid supply section is located below the working surface of the ion selective electrode, and the liquid supply section is located below the working surface of the ion selective electrode. A measurement device for measuring the activity of a specific ion in a test solution, which has at least a horizontal passage for horizontally moving the test solution or reference solution directly below the working surface of each ion-selective electrode. a sheet-like porous member having a water-impermeable region adjacent to a water-permeable region is filled between the horizontal channel and the working surface of the ion-selective electrode; 2 for raising said test or reference liquid from the horizontal passageway to the position of the working surface of each ion-selective electrode;
Each of the above-mentioned ascending passages is configured respectively, and each of the water-permeable regions is adjacent to the water-impermeable region so as to be completely included in the working surface of the corresponding ion-selective electrode. Quantity measuring instruments. 2. A planar water-impermeable partition wall is provided between the sheet-like porous member and the ion-selective electrode, and the partition wall projects from the porous member directly below the working surface of the ion-selective electrode. Claim 1, characterized in that the partition wall has an opening that allows the opening, and the thickness of the partition wall is such that the sample liquid and the reference liquid do not cause capillary action along the wall surface around the opening. The ion activity measuring device described in Section 1. 3. An upper frame body having a pair of openings through which a test liquid and a reference liquid can be supplied from the outside to the horizontal passage, respectively; a pair of openings communicating with the pair of openings; a lower frame having a partition wall and a recessed portion forming the horizontal passage; the at least one pair of ion selection electrodes are housed in the upper frame; and the sheet-like porous member is arranged between the partition wall and the lower frame. The ion activity measuring device according to claim 2, which is housed between the body. 4. It has at least two pairs of the ion selective electrodes and two sheet-like porous members, one of the porous members having two or more rising passages for the test liquid, and the other having two or more rising passages for the reference liquid. The ion activity measuring instrument according to claim 1, characterized in that each of the above rising passages is formed. 5. A patent claim characterized in that a part of the surface of the sheet-like porous member is coated with a water-impermeable substance, thereby forming a water-impermeable region in the porous member. The ion activity measuring instrument according to item 1. 6. Claim 1, wherein a portion of the sheet-like porous member contains a water-impermeable substance, thereby forming a water-impermeable region in the porous member. The ion activity measurement device described. 7. The ion activity measuring instrument according to claim 1, wherein the sheet-like porous member is made of long-fiber cellulose. 8. The ion activity measuring instrument according to claim 1, wherein a band-shaped porous member is accommodated in the horizontal passage.