JPS582646A - Ion selective electrode - Google Patents

Abstract

PURPOSE:To lengthen the life of an electrode and reudce the time of replacing it for a new one which involves difficult work and reduce high cost of ion selective films by providing in an ion selective electrode a mechanism to supply automatically a plastic agent to an iron selective film. CONSTITUTION:An ion selective film 26 that consists of a sheet formed by impregnating a high molecule film such as PVC, etc. with a hydrophobic neutral carrier (crown ether group, Valinomycin, etc.) and a plastic material such as dioctyl phthalate, etc. is airtightly attached on the cylindrical wall 27 at the opening 22 at the bottom of a cylindrical electrode body 21. The solution 24' of a material such as KCL, etc. that is electricity conductive by ionization and an internal standard electrode are put in a first chamber 24 that includes the opening 22. A first chamber 24 is divided from a second chamber 25 by a partition 23 air-tightly. A third chamber 28 is formed annularly over the whole of the bottom periphery of the first chamber 24 by means of film 26 and wall 27 and a wall 29 or a plurality of third chambers 28 through the wall 27 connects the chamber 25 and the chamber 28, and the opening section to the second chamber 25 is closed tightly with a film 31 impermeable to plastics. A plastic material 28' is sealed into the chamber 28. When the electrode is submerged in a specimen such as blood serum for a long time, the plastic material is supplied automatically to the film 26 with this arrangement and the life of the electrode is made long.

Description

[Detailed description of the invention] The present invention is an ion-selective electrode with a long service life.

More specifically, the present invention relates to an ion-selective electrode equipped with a mechanism for preventing ion-selective membrane O deterioration.

Ion-selective electrodes are round-shaped analytical instruments that selectively quantify specific ions present in liquids, and are used across the IK field, such as monitoring specific ion concentration and water quality analysis. ing.

Generally, an ion selective electrode has a structure as shown in the 11th schematic diagram. That is, there is an opening 11 at the tip.
The sample liquid should be protected from illegal materials (e.g. polyvinyl chloride) with a hollow cylinder (e.g. circle II).
); cough opening 11K; for example, an ion-selective membrane 13 that is glued to close the wrinkle area + axillary electrode hook body νO;
1 wall 16 forming a second m1S opposite thereto, an ionically conductive substance 14', such as an electrolyte solution; It basically consists of an internal reference electrode 17 which is held in an air-like manner by 111116, and a tin lead which is drawn out from the wrinkled internal reference electrode to the outside of the wrinkled electrode cylindrical body through the wrinkled electrode cylindrical body 21115. ing.

To quantify the concentration of a specific ion, place the tip of the electrode in the sample solution,
That is, it is carried out by immersing a portion of the selective membrane 13. □ The ion-selective membrane 13 used is JP selectively permeable to specific ions to be analyzed present in the sample solution when the electrode is immersed in the sample solution. It is a flexible polymer membrane that is impermeable to other substances. In this type of agriculture, the specific ions targeted are NH” J Na” I
In the case of K” r.

Tictin, monensin, nigericin, palinomycin, cucun ether chain I, etc., respectively, with an aqueous neutral carrier, diotatyladibate, dioctyl 7-thaletate, dibutylic acid/diptylate,
Polymer substances such as polyvinyl chloride membranes and polycarbonate membranes are made to contain plasticizers such as dibutyl 7 tallate (su/ml), dibutyl 7 tallate, and didefluphthalate in a predetermined amount. It can be obtained by forming the blend into a sheet using a conventional method.

When such an ion-selective electrode is immersed in a test liquid,
The o4I constant ion 0 ion activity a in the test solution and the potential E and 0 shown by the ion-selective membrane @.

The following formula: % formula %) (In the formula, R is the gas constant, T is the gloss vs. temperature range of the test liquid, 2 is the ion valence of the specific ion, F is the constant constant, and 1t@ is the system OII quasi-potential.

be. When 1 is the cation activity, the sign ←) in the formula is used, and when 1 is the ion activity, the sign ←) in the formula is used.

) is based on the Nernst relational formula. the result,
The activity of a specific ion of interest can be easily calculated from the fixed potential OII of the system. Therefore, if an ion-selective electrode is used.

By simply adjusting the potential indicated by the line electrode, it is possible to quantify the concentration of a specific ion of interest over a wide concentration range. On the other hand, if the electrolyte section is made small in size, measurement will be self-wearing even if the sample liquid is small.

As described above, ion-selective electrodes are very convenient, and recently there have been many attempts to use them for W7I applications, particularly for the determination of various ions dissolved in blood, such as K, Na, and C. ing.

However, when an ion-selective electrode is used for a long period of time, constituent components of the ion-selective membrane (such as plasticizers) become Ki! I put it out.

Or vice versa, by introducing impurities in the test solution]
Deterioration of g activity progresses. For example, when the plasticizer contained in an ion-selective membrane is depleted, the neutral carriers that were present during KM within the membrane precipitate within the membrane and have the ability to form a complex with a specific ion to be analyzed. It is thought that the corrugator membrane ceases to respond to the Nernstian response as a result of a decrease in the number of molecules in the corrugator membrane or a decrease in its mobility within the corrugator membrane. If the test liquid is blood, serum, etc.

Due to the nature of KII in blood and serum, a certain percentage of KII in blood and serum is absorbed (9), and the ion-selective membrane may be eroded by bacteria present in the test fluid. Therefore, the Nernst response of the ion-selective membrane 11AK cannot be obtained even after a short period of use, leading to the inconvenience of the electrode's service life being significantly shortened.

Conventionally, this rounding occurs when the ion-selective membrane deteriorates and a Nernst response cannot be obtained.

Each time, the ion-selective electrode must be discarded and replaced with a new ion-selective electrode, or the deteriorated ion-selective membrane must be removed from the electrode and replaced with a new ion-selective membrane. Measures were being taken. However, the former measure is economically disadvantageous because the ion-selective electrode is expensive, and the latter O measure is preferable because the operation of replacing the ion-selective membrane is extremely difficult and complicated. It's a thing.

In order to solve this problem, an ion-selective electrode with degraded membrane activity can be prepared by dissolving the same constituents of the ion-selective membrane used in the cough electrode in a stronger S medium such as tetrahydrofuran. A method has also been proposed in which the material is immersed in an S solution for a certain period of time, and then the solvent is removed by drying for activation and regeneration (Japanese Patent No. 54-26791).

However, with this method, the activation and regeneration effect of the membrane is not necessarily satisfactory. Moreover, if the regenerated tK# electrode is immersed for a long time in order to obtain a sufficient regeneration effect, the inconvenience arises that the membrane itself dissolves due to the harsh action. One of the disadvantages of gloss is the economical disadvantage that the regenerating liquid itself is 9-14-valent, which contains the same components as the membrane components. The present inventors have solved the drawbacks of the above method. As a result of extensive research, we have determined that the ion-selective membrane with degraded activity can be treated with a plasticizer of the same type as the plasticizer that is a component of the axillary membrane, or with a different type of plasticizer than the scissors plasticizer. /I! Even when it comes into contact with a plasticizer which is an i agent and has the ability to dissolve the neutral carrier which is another component of the film and can impart 1iT* properties to the wrinkled film, the film's 0 activity is regenerated. I discovered the fact that Nernst's L answer was recovered. Although the rationale for the scissors fact is not necessarily clear, the nine plasticizers in contact with the nine ion-selective membrane deteriorate, resulting in diffusion within the scissors membrane.

It is believed that rounding would restore the complexing ability of the neutral carrier or its mobility within the membrane.

Therefore, based on the above-mentioned facts, the inventors of the present invention have proposed '11. By incorporating a mechanism in the ion-selective electrode to automatically supply plasticizer to the ion-selective membrane, the ion-selective electrode of the present invention has a long service life.

The purpose of the present invention is to provide an ion-selective electrode whose ion-selective membrane does not deteriorate even when immersed in a test solution for a long time, and which has a long service life. , a hollow electrode cylinder with a tip K11 opening; an ion-selective membrane consisting of a round, knitted layer that seals the scissor opening, and a molecular membrane containing a hydrophobic neutral carrier and a plasticizer; The inside of the body is divided into the axillary-oral area and the 2nd m029 located on the opposite side.
A good ion conductive material is enclosed within the ion conductive material;

A toad and
In an ion-selective electrode consisting of a lead which is drawn out from the system through a second electrode from the internal reference electrode, #1
ff1iK is a cavity disposed at the base of m and having a wrinkled ion-selective membrane as part of the boundary wall, in which ff1iK is a cavity containing the plasticizer contained in the ion-selective membrane and the plasticizer of Pls+. or, the plasticizer is a 14fIM plasticizer, which has a solubility in the iron neutral carrier and is encapsulated with a plasticizer that gives flexibility to the axillary ion-selective membrane; An air flow path toss disposed from the third to the second iron chain, and the opening S of the scissor air circulation path a to the iron chain 2'M were sealed and attached. It is characterized by having a structure including a membrane that is permeable to air and impermeable to the scissors obscuring agent within the axillary irises.

The ion selective electrode having the structure of the present invention will be explained below by referring to an embodiment shown in FIGS. 2 and 3. FIG. 2 is a schematic vertical sectional view, and FIG. 3 is an enlarged view of the tip portion in FIG. 2.

In the figure, 21 is an electrode cylinder (for example, a cylinder) that is elongated and hollow inside, and has one tip (bottom 1i in the figure).
i) opens to form Sekiguchi Iin.

The other end (part 111 in the figure) is pierced. is a shielding wall that divides the inside of the electrode cylinder into two parts, and has an opening s22.
Including 11th i! 24 and the second wealth 6 located above in the figure.
form.

is an ion-selective membrane with an opening η in the electrode spacing.
is hermetically sealed. The sealing operation is performed by adhering the peripheral edge of the ion-selective electrode to the hooked wall r of the electrode cylinder 210 with a suitable adhesive.

The first mass is filled with an ion-conductive substance h', which contains the defined ions to be analyzed, and which directly interacts with the ion-selective membrane pressure on its surface. It goes without saying that we must make contact.

The channel is a gS-rich structure that imitates the structure of the electrode of the present invention, and is provided at the base of the first chamber, and both the ion-selective membrane and the cylindrical wall 4 are made of -S, respectively. 1129 is configured as the other O boundary wall.

By bonding the lower end of the mural fi& with an ion-selective membrane as shown in Figure 1, for example, an independent internal space is formed within the chamber U in the wall 31i [28]. In this space, the plasticizer A' mentioned above is sealed in 11.
The wrinkle plasticizer comes into contact with the surface of the ion-selective membrane.

In response to the formation of the 5th m28, its boundary tllo-corridor must necessarily be composed of an ion-selective membrane strand. Otherwise, the effect of the invention will not be achieved, since the plasticized copper-tin' enclosed within the third m cannot come into contact with the ion-selective membrane pressure.

ζ0 so 1 to 31i12B, 111240th base)
It may be formed in an annular shape along the entire periphery, or it may be formed in a number of nine independent rooms.In any pigeonhole, a part of the tomb wall (Hawk II) is Must be a selective membrane.

I is bored inside the scissor cylinder wall 270 from the cylinder wall located above the wave direction of the plasticizer grave' and within the third chamber row, and the second Wi
This is the air flow path leading to SK. The air flow path I prevents the progress of reduced pressure in the third enrichment section due to diffusion into the ion-selective membrane. Therefore, the opening to the air flow am3oogz rich.

It is sealed with an O membrane 31 that is permeable to air and impermeable to the plasticizer 2B'. For such a film, 1
For example, cellulose acetate 1Ili*f7"7 membrane can be used. In Figure 1, the air flow path t is bored inside the cylinder wall n. For example, it can be formed by a thin hollow pipe passing through the ammu and l1129 and passing through the inside of the second @2A.

The proverb is that the electrode is immersed in an ion-conductive material and is fixed in place with the trachea in place with a clasp 1123.
The upper part is illustrated at No. 21125. Internal reference voltage @
An additional lead wire for taking out the electrical signal (potential) of the internal reference electrode O is connected to the upper end of the XZO, and the lead wire is led out of the system using the 2115th wire.

Since the ion-selective electrode of the present invention is configured as one or more, the ion-selective membrane can maintain ion-selectivity even when rolled up, where a plasticizer is always supplied to the ion-selective membrane, or when immersed in a test solution for a long time. Deterioration of membrane activity due to elution of plasticizer in the membrane can be prevented.

For example, a potassium ion/selective membrane made of polyvinyl chloride containing palinomycin and dioctyl adipate as the ion-selective membrane, a potassium chloride solution as the ion-conductive substance, a silver-silver chloride electrode as the internal reference electrode,
A thin tear film was used as the film J, and the 31i! 28 is filled with dioctyl adipate and shown in FIG. 3 is the electrode of the present invention (electrode 1); An electrode of the present invention (electrode 1i2) was prepared. For comparison purposes, an electrode (electrode 3) 4 with the structure shown in the gt diagram and each element having the same structure as the electrode 1 and the electrode 3 was prepared.

While immersing these three O electrodes in serum (37C) with an indigo concentration of 4.4 x 1 G M, the above serum was diluted [(
The potential (4 mK) between the serum and the serum was traced for each electrode.

The results were shown as $14-6ia. As is clear from the figure, the ion-selective electrodes of the present invention (Electric @l, Electron I
IIA2) are all conventional O ion selective electrodes (electrode 3
), it has been found to be more wearable and has a longer usable life.

In addition, in the examples, the ionic conductive material and =rm,
However, the plasticizer, which dissolves the lipophilic ion conductive substance and does not penetrate into the electrode, is stored in the ion conductive substance (for example, the lipophilic ion conductive substance). Conductive substance: system consisting of methyltrioctylammonium chloride, plasticizer nidioctyl adipate,
Alternatively, if the lipophilic O iono-conductive substance: potassium tetraphenylborate, the plasticizer nidioctyl adipate, and the permeating agent: nitropene are sealed in the first imperial chamber, it is not necessary to form the iris three wealth. becomes. When Jin
If a neutral carrier is dissolved in the plasticizer, it is possible to prevent the neutral carrier in the ion-selective membrane from entering the plasticizer.

As is clear from the above explanation, the ion-selective electrode of the present invention has a significantly longer lifespan for I2 hemorrhoids, and has great industrial value.

[Brief explanation of the drawing]

$1 [Figure is a schematic diagram of an ion-selective electrode with a conventional structure, Figures 2111 and 3 show one example of the ion-selective electrode of the present invention, and Figure 2 is a schematic diagram thereof. Figure 3 is #l2I
It is an enlarged view of the tip part in a. Figures 4, 115, and 6 each represent changes in the output potential 0 of the ion-selective voltage Ii, and Figure 4, jlSl
1I is 4 related to the W14K of the present invention, and FIG. 6 is 4 related to the electric 1iK of the conventional structure. 11...- Mouth 1II12... Electrode barrel 13... Ion selective membrane 14... No. 11114'... Ion conductive substance Intestine...-Kai 21i116-41 IIB
...electrode spade body η...-qla Zll...shoe wall...
...No. 11124'...Ion-conductive substance 2...Second child song--Ion-selective membrane n--Cylinder wall for -j13m〆...Plasticizer
Vessel...Mural...Air circulation path 31...
Membrane proverb: Internal reference electrode

Claims (1)

[Claims] A hollow electrode cylinder having a tip llIc1lI opening;
An ion-selective membrane consisting of a monomolecular membrane containing a hydrophobic neutral carrier and a plasticizer is attached between the openings and a first enriched membrane containing a and the second wall located on the opposite side divided into two parts II-1 wall; It is sealed in the scissors 1 chamber and immersed in an ion conductive material containing nine ions/conductive material, and is fixed by the footwall and formed into a round shape. an internal reference electrode; and In the ion selective electrode that is connected to the lead wire drawn out from the axillary internal reference electrode to the outside of the system via the axillary second electrode, the 11i10
It is a vacant space disposed at the base and has the scissors ion-selective membrane as a part of the boundary wall, of which 11K is made of plasticizer of the same type as the plasticizer contained in the ion-selective membrane, or , which is different from the plating agent, is a 5toiT obfuscating agent, which has a dissolving agent for the wrinkle neutral carrier and provides flexibility to the wrinkled ion-selective membrane. 31il Airflow passageway is arranged from the 3rd floor to the 2nd floor. Scissors air distribution roar O armpit second emperor 011 mouth 1tll! And be attached! An ion-selective electrode having a rigid structure and having Ol[i] which has low permeability and is impermeable to a wrinkle-free axillary agent.