JPS58102147A - Measuring device for ion activity - Google Patents

Abstract

PURPOSE:To perform an engagement with an accurate matching property, by a method wherein a frame and a cover, into which an ion select electrode body can be built, have at least a pair of engaging parts. CONSTITUTION:Two electrodes are placed on a frame 31 away from each other, and the opposite ends of the frame 31 form engaging partners 310 on one side for mating a cover 32. The cover 32 has partners 320 which form two sets each consisting of a pair of the engaging parts for mating the partners 310 of the frame 31. The frame 31 and the cover 32 are excellently matched with each other for engagement, and built-in electrodes 10 are physically held in a given position by forming a pair of engaging parts consisting of the engaging partners 310 and 320. Bridges 20 are placed in a constant position on the cover 32, and if an engagement of the frame with the cover is conducted, the bridges 20, located in a constant position, are automatically held in a required constant position on the electrodes 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion activity measuring instrument that allows easy positioning of an ion selective electrode and a bridge, and prevents shorting due to a test liquid or a reference liquid.

As a device for measuring the ion activity in a solution, a measuring device by Hashira, which incorporates an ion-selective electrode, has been proposed.

For example, "Research Disclosure" magazine, Vol. 175-17517 (published in November 1978) has a built-in ion-selective electrode that generates a potential proportional to the logarithm of the ionic activity of the ion to which the ion-selective electrode is sensitive. A device for measuring ion activity has been described. In this measuring instrument, two solid electrodes are attached to the frame, and a bridge having a capillary function is further provided to promote ion movement between the two liquid spotting holes. When a reference liquid droplet is supplied to one spotting hole and a test droplet is supplied to the other spotting hole, the capillary function of the bridge causes contact between the two liquids and ion transfer between the droplets. It will be done. By measuring the resulting potential, the ion activity in the test liquid can be determined.

The above-mentioned ion activity measurement becomes possible only when the ion-selective electrode, Q, and D fully perform their respective functions. That is, a liquid sample droplet spotted through the spotting hole must cause ion movement due to the capillary action of the bridge and wetting of the solid electrode surface resulting in a potential proportional to the logarithm of the ionic activity to which each solid electrode is sensitive. However, for this purpose, the relative positional relationship between the bridge and the electrode becomes a problem. If the bridge is not held in place on the electrode, the 1ll
Correct positioning of the bridge relative to the electrode is extremely important since wetting of the c-electrode surface is not achieved. In addition, ion activity measuring instruments were manufactured and JI
J! There is always a lapse of time before the electrode can be used for measurement, and the bridge must be held in place over the electrode until the time of measurement, so fixing the bridge to the electrode solves the above problem. It was thought that it was a suri. Based on this idea, a technique was proposed in the above-mentioned Research Disclosure magazine in which a bridge is fixed to an electrode using an adhesive. In the first place, the bridge is manufactured as a separate part independently from the ion selective electrode, so it is easiest to fix the bridge by gluing these parts together using adhesive. It is a means. It has been evaluated that this setting provides satisfactory results to a certain extent.

However, since the bridge member is a separate and independent part, when assembling the measuring instrument, it is necessary to apply adhesive and adhere the bridge member to a predetermined position on the electrode for accurate positioning. First, such limitations increase the complexity of assembly, and there is a risk of performance degradation due to misalignment of the spotting holes or peeling of the adhesive used. Tokusho 56-61481
has been pointed out.

In order to solve this complicated assembly, we abandoned the research disclosure magazine's technical orientation of determining the relative positional relationship between the bridge and the electrode, which are separate and independent parts, and instead used adhesive. Rather, a method was proposed in the above-mentioned Japanese Patent Application Publication No. Sho, in which the bridge itself is held in place and a separately manufactured ion selection electrode is assembled so as to be aligned therewith.

That is, one cover sheet is provided that covers almost the entire surface of the frame on which the electrode pair is placed.

The bridge member was encapsulated in the cover sheet in the form of a ribbon.

``Buried'' refers to plastic (which is the raw material for the cover sheet)
Polystyrene is exemplified) as a film in a molten state, and this film is brought into contact with a porous material constituting the bridge in an unsolidified state before being completely cooled.
It is formed by a special method of crimping between a pair of rollers. According to this method, the bridge is
Embedded in plastic without using adhesives, which can cause defects in conventional technology, so-called "encapsulation"
It is set up in a state where The ribbon-like "embedded" or "encapsulated" bridge can indeed be positioned without adhesive, which is advantageous for the assembly of the device in the intended continuous operation.

However, as mentioned above, 1.
Polystyrene, which is a highly elastic fluid, is used as a solid bridge member with low elasticity, such as ribbon door paper, and the thickness is controlled by compressing fluids and solids with different elasticities. This unnecessarily complicates the process. Further, fluid can be considered to be intangible, and it is difficult to embed a bridge member, which is a tangible object, in such an intangible object to achieve positional alignment. Even if the bridge position is ideal,
It is also difficult to achieve positional alignment to prevent further positional deviation with the electrodes in continuous processes.

Particularly when attempting to automatically manufacture ion activity measurement devices as intended by this method, there is a high risk that misalignment of the becomes larger.

The inventors of the present invention have conducted repeated research to eliminate the above-mentioned drawbacks of the known techniques, but in order to realize the bridge installation technique as disclosed in Japanese Patent Application Laid-open No. 56-61481, an extremely sophisticated and complete operation is required. However, even if such a technique is carried out under ideal conditions, we are aware that there is still the risk described above in instrument assembly (1 stage), and we are trying to improve the performance of ion activity measuring instruments from a completely new direction. As a result of pointing to 0,
It has been found that the inconveniences and shortcomings of the conventional method can be overcome by housing the ion-selective electrode in an instrument frame comprising at least one pair of retaining parts and consisting of nine frames and a lid.

The frame and the lid are provided therein and form a closed space whose free movement can be restricted by the joints, and when the ion selection electrode is located in the space, it is automatically fixed on the frame. Positioning the bridge with respect to the ion selective electrode fixed and housed in good condition in this manner is extremely easy and simple.

The electrode-to-bridge positioning employed in the present invention is not only relative to the electrodes as in the prior art (in which case the bridge is positioned only relative to the electrodes).

If the electrode itself has room for free movement, adhesive fixation of the bridge would be useless), and/or there is no means for aligning the electrode with respect to the bridge. The main focus of this 1jlIK is that if the electrodes themselves are fixed so that they cannot move freely, the position of the bridge relative to the fixed nine electrodes can be easily achieved, which is completely different from the solutions in the prior art. means.

In this way, the present inventors have devised an instrument frame for an ion-selective electrode in which the ion-selective electrode can be housed easily and with more reliable positional consistency without the complicated operations required in the prior art. This is the book in which the invention was completed.

It is therefore an object of the present invention to provide an ion activity measuring instrument incorporating an ion selective electrode in an instrument frame which is held together with precise alignment.

The ion activity column meter of the present invention has (II) at least two ion-selective electrode bodies (to) a frame and a lid that can be formed by incorporating them, and (3) a bridge, a membrane frame, and a lid. and a pair of retaining parts.

What does "at least a pair of retaining parts" refer to in the present invention?

For example, as shown in Figure 1, if the frame has a recess, this means that the lid is provided with a protrusion that can physically engage with the recess, and the three engaging parts are They are called a pair of holding parts.

The function of this retaining portion is to physically engage the frame and the lid to position the electrode and the bridge, and as long as this function is achieved, any form of retaining may be used.

A space for incorporating a pair of ion selection electrodes is secured inside the instrument frame consisting of a frame and a lid. Therefore, the structure of the retaining parts that engage with each other is primarily determined by the size of the ion selection electrode.

A known electrically insulating material is used as the material for the frame and the lid. Typical examples include self-supporting polymeric substances 1 such as polyethylene, polystyrene, polyethylene terephthalate, polycarbonate (Bis 7, Norm, etc.), cellulose acetate, and the like. The frame and lid may be made of the same material or may be made of different materials.

The features of the ion activity control device of the present invention will be explained in more detail with reference to the drawings.

FIG. 811 is a conceptual diagram showing the structure of a measuring instrument showing a preferred embodiment of the present invention. Two electrodes, designated lO, are mounted spaced apart from each other on a frame 31 whose ends form one retaining partner 310 for engagement with the lid 32. This engagement partner 310 has a bulk, which is greater than the height of the electrode 1! %/h.

The lid 32 has rounded hardeners 32 at both ends thereof that engage with retaining partners 310 of the frame 31 to form two pairs of engaging portions.
has 0. The engagement height b of the locking partner 32G is a
It is configured to satisfy the relationship +b>c. Frame 3
1 and the lid 32 fit together well, and the locking partner 3
10, 320 to physically hold the built-in nine electrodes 10 in a predetermined position.

When the bridge 20 is placed in the fixed position on the lid 32 and the engagement between the frame and the lid is formed, the bridge 20 placed in the fixed position on the lid 32 is automatically connected to the electrode. 10 in the desired fixed position.

FIG. 2 is a sectional view showing another preferred embodiment of the measuring instrument according to the present invention. In order to securely hold the electrodes 2111 in a spaced relationship, a space 321 is provided in addition to the retaining partner for the retaining portion of the pair of lids 32KFil.

Since the spacer reliably maintains the separated position of the electrodes, it is not necessary to form a connection between the frame and the lid, and it is sufficient to isolate the pair of built-in electrodes. Therefore, either the frame or the lid may have a spacer.
(Figures 5 to 5) The spacing portion may also be configured to further form an engagement between the frame and the lid at the position indicated by reference numeral 311 (see FIG. 6).

Figure 7 shows a silver layer 1 in the frame of the Marubuchi fixed instrument by breaking the locking with the same pair of frame-lid engaging parts as shown in Figure 1 and 9.
1 and a silver chloride layer 12, a common support 19 and a common ion selection layer 14 are provided at the positions shown in the figure. This shows a preferred embodiment of an electrode device incorporating a so-called twin-lid electrode. It is a conceptual diagram.

Above, in FIGS. 1 to 7, nine measuring instruments each having a built-in electrode of the type used for one-item inspection have been illustrated. For example, the electrodes incorporated therein can be appropriately selected depending on the purpose. For example, for one reference electrode, 1
It is possible to combine two or more sample liquid spotting electrodes into a jug-type measuring device, or to combine two or more sample liquid electrodes, or to scoop multiple items at the same time. It is possible to construct a so-called multi-type measuring instrument in which a plurality of test liquid electrodes and corresponding reference electrodes are incorporated in the necessary line arrays.

As described above, the frame-lid connection is achieved and the m'ila of the present invention is achieved.
In this case, the electrode lO is connected to the frame 31 by the engagement formation.
and the bridge 20
Since the edge of the bridge 20 is not aligned with the edge of the electrode 10, even if the test liquid or the reference liquid leaks from the end of the bridge 20 and flows down, the leakage liquid will cause the electrode to become damaged. There is no risk that the nine predetermined areas of the surface of lO will be affected.

In the present invention, the positional relationship between the bridge, the frame, and the lid can be determined at a relatively arbitrary position because the frame and the lid are integrated by the above-mentioned formation. It is desirable to first position the bridge by providing a ninth positioning guide in advance. By providing this guide, positioning when adhesively fixing the bridge to the lid becomes easier. Preferably, a guide is provided in advance on the upper surface of the lid, the shape of which is approximately the same as the outer periphery of the bridge, so that the bridge can be accommodated by fitting the outer periphery of the bridge. A perspective view of a round lid designed to be used for positioning is shown. Another method of placing the bridge in a specific position is to punch out a part of the lid and insert the bridge 20 into the punched out part, as shown in FIG. Providing a pair at both ends of the lid 32 also facilitates positioning of the bridge 20. The protective frame 322 is used to position the bridge 20, but it also has the function of protecting the measuring instruments from physical damage when storing and transporting a large number of measuring instruments stacked on top of each other. has.

For the ninth position of the bridge, it is also convenient to provide a positioning guide on the gold plate 32 as described above. 12th
Figures 1 through 14 are diagrams illustrating the preferred shape of such a guide. In FIGS. 12 and 13, a guide 323 is provided at a desired position on the surface of the lid 32, and when the bridge 20 is accommodated in the U-shaped guide 323, the bridge 20 can be held in a fixed position. K is set so that I can do it. FIG. 14(c) K shows a state in which a guide 323 shown in (b) K, which has a shape and size that can completely accommodate the bridge 20 shown in (a) K, is fixed on the lid 32.

That’s it! Therefore, it is sufficient that the bridge 20 is attached to the lid 32 with its movement restricted.
There is no need for "layering" or "encapsulation" through complicated operations as in the prior art.In the present invention, as mentioned in #i, the positioning of the bridge is primarily based on the maintenance between the frame and the lid. This is achieved by mating and is preferably fixed in a precise position by a kite provided on the lid. In the present invention, the fixing of the bridge takes place primarily by gluing. In other words, although the bridge is only placed on the lid, it is precisely positioned by the engagement between the frame and the lid, so the bridge functions to its fullest and provides highly accurate measurement data. contributes to obtaining.

In the ion-selective electrode device of the present invention, the ion-selective electrode comprises at least a conductor layer and an ion-selective layer or a protective layer. The ion-selective electrode is further coated with an electrolyte layer (
provided between the conductive layer and the ion selective layer).

An example of the layer structure of a typical ion selective electrode is as follows.

(1) Conductive metal layer and ion selective layer (1) Conductive metal oxide layer and ion selective layer (31 conductive metal layer, water-insoluble salt layer of the same type of metal as #metal and ion selective layer (or protective layer) ) (4 conductive metal layer, water-insoluble salt layer of the same metal as the metal, electrolyte layer, and ion selective layer 4 conductive metal oxide layer, electrolyte layer, ion selective layer, etc.)

In any of the above cases, if the conductor layer has self-supporting properties, it is as it is, and if it does not have self-supporting properties, it is formed as a layer on a suitable support.

As the conductive metal and metal oxide constituting the electrode, metals used in known electrodes can be used. Examples include silver, copper, platinum, gold, etc., and oxides thereof.

Examples of water-insoluble salts of conductive metals include pagenides (for example, Age/, muggr, mugI), sulfides (
For example, there are Mugs 8, Ou, 8, etc.).

The electrolyte layer is a layer of an electrolyte having an anion common to the anion of the above-mentioned water-insoluble salt, for example, a main compound of monomer, sodium, calcium or sulfide (K
, Na 01 , Kl 8, etc.). The electrolyte layer can be of a water-containing type or a dry type, and ions with a constant rate of 1% can be selected.'' This means not only when specific ions are selectively permeable or sensitive, but also when ions with a constant rate of 1% are measured. This also includes cases where the substance can be selected from other substances not to be measured with a sufficient time difference between the two. Depending on the material used for the ion-selective layer, the potentiometric response corresponding to the change in ion activity in the liquid may be measured through ion exchange, and as a result, the same function as that of a % constant ion may be achieved. It is also called 1 which can select ions with a certain percentage.

Since both the test liquid to be fixed and the reference liquid used as necessary in the present invention are aqueous liquids, the ion selective layer must be water-insoluble. It may be hydrophilic or hydrophobic as long as it is water-insoluble. What is the most typical ion selective layer?

The ion carrier consists of an ion carrier, an ion carrier solvent, and a hydrophobic organic binder (or a matrix consisting of a hydrophobic organic binder).Ion carriers include padanomycin, cyclic polyethers, tetralactone,! These include chloride actin, enninatine group, polymers, gladencidins, nonactin group, tetraphenylborate, cyclic polypeptides, and the like.

As an ion carrier solvent, bromo78yl-13
-methoxy78nyl- and 4-methoxyf, nirouf,
dimethyl-, dibutyl-, dioctyl-7-talate, etc.

Examples include dibutyl sebacate.

Hydrophobic organic binders include hydrophobic natural or synthetic polymers that can form thin films (eg.

cellulose esters, polyvinyl chloride, polyurethane, etc.).

Ion exchange resins can also be used as materials for the ion selective layer. When an ion exchange resin is used, the ion activity in the ion-containing solution changes due to ion exchange, which results in the measurement of the potential difference response.

The ion exchange resin may be either cationic or anionic, and includes, for example, quaternary alkali ammonium, phosphonium, and arsonium.

Examples include stibonium or sulfonium ions, dialkyldithiocarbamates, diketones, and sulfonated polystyrene.

In addition, regarding the ion selective layer, the ion which determines Il,
It is essential when e is 0 for K, Na", On", HO, but the ion to be measured is Olo, the conductor layer is made of silver, and the water-insoluble salt is made of silver chloride. In some cases, an ion selective layer is not required. The cellulose ester lRh described in JP-A-55-89741, JP-A-55-89741, JP-A-72622 and JP-A-54-13.
A layer formed from the latex or the like described in 84 is provided as a protective layer permeable to ions to be tested.

Each constituent material of the ion selective electrode used in the present invention is known, and a known method can be applied to layer formation. Regarding conductive metals and metal oxides, see JP-A-52-142.
5114. 49-128793, Special Publication No. 52-477
17 and Per Kofstad 41rNon-st
oichiametry.

Diffusion and glectrlca
l Conductivity 1nBinary
fnetal OxidesJ Published by Lee Interscience Co., Ltd. (Nie Xi-1), 1972 M
U.S. Pat. No. 42 for material and formation of the electrolyte
No. 14968% JP 52-142584 and Patent Application 1973
5-92379: Regarding the ion selective layer, see JP-A-52
-142584. US patent! No. 4053381, 41
No. 71246.

It is detailed in No. 4214968 and "Research Disclosure" magazine Hobun 111s, 16113 (September 1977 issue).

Known materials can be used as the material of the pudge, which is formed into a round shape that promotes ion transfer between the test liquid and the reference liquid required for adjusting the potential difference. Typical examples thereof are porous materials such as papers made of natural and/or synthetic fibers, mixtures of Membrane Filter-1 thickeners and polycarbonates or polyamides. For more details.

The following is a naturally porous material.

+11 Pulp made of synthetic polymer fibers (polyethylene, polyethylene terephthalate, cellulose ester, etc.) and pulp made of vegetable natural fibers (cotton pulp, linter pulp).

Flax (Itnen) pulp, Kozo (Browsmon)
atlaKazinoki 8ied) Pulp, Mitsumata (1!idg*worthia Papyr order)
a 8ied at Zucc,) pulp, etc.) (2) Paper made only of the above synthetic polymer fibers (Sono Synthetic polymer fiber Ia (polyethylene terephthalate,
Cellulose ester, boriaod.

(4) Plain woven fabrics (kinkin, broadcloth, boblin, etc.) made of the vegetable natural fibers (3) above (5) Cellulose A membrane filter made of ester or regenerated cellulose (preferably an average pore size of 2 μm)
(6) Membrane filter containing nitrocellulose as a main component (preferably average pore diameter of 10 μm or less) (71 Paper made from pulp made of vegetable natural fibers and compressed (P paper, absorbent paper, etc.) It is sufficient that at least one surface of the bridge is made of the above-mentioned porous material.

A coating film of the porous material may be formed on a hydrophobic material such as plastic and used as a bridge. More details are described in Japanese Patent Application No. 86-112030.

As described above, the ion activity measuring instrument according to the present invention enables highly sensitive ion activity measurement with good reproducibility by engaging the frame and the lid.

[Brief explanation of drawings]

1 to 7 are cross-sectional views showing various aspects of the frame-lid attachment in the ion activity measuring instrument of the present invention. FIGS. 8 to 14 are perspective views of the lid showing various positions for positioning the ion activity measuring instrument of the present invention during bridge placement. The main symbols in the figure are as follows. lO...Ion selection electrode 20...Bridge 28...Test liquid spotting hole 29...Reference liquid spotting hole 31...Frame 310...Holding section 311...Spacer 32...Lid 320...Holding Part 321...Spacer 322...Passus frame 323...Guide size and 1 word are compared.
1wk Mr. Fuki Tone as agent 4F Riju N'
γ River 1 叡Se ((Siri・1mu) lso fig. 12 fig. 13

Claims (1)

[Claims] l An ion activity measuring instrument comprising at least two ion-selecting 11 electrodes, a frame on which the ion-selecting electrodes are placed, at least one bridge communicating between the electrodes, and a lid. , an ion activity measuring instrument characterized in that the membrane frame and the core portion are provided with at least a pair of retaining portions. (c) The ion live lid measuring instrument according to claim 1, wherein the bridge is not embedded in the lid but is placed on top of the ★.