JPS60201245A - Ion selective electrode and ion sensor body - Google Patents

Abstract

PURPOSE:To improve sensitivity and responsiveness and to enable ling-term continuous measurement by providing a specific cellulose ester film on the surface of an ion sensitive film. CONSTITUTION:An insulator 1 of an empire tube is coated on an Ag wire 3'. An Ag/AgCl part 3'' is formed on the top end of the wire 3' by electrolyzing the same in KCl and coating an AgCl layer on the surface of the AG wire thereby constituting a conductive member 3. A liquid prepd, by dissolving PVC contg. quaternary ammonium salt is coated on the surface of such member 3 and is dried to form an ion sensitive film 4 consisting of a PVC resin contg. 25% quaternary ammonium salt as an ion selective material to about 300-450mum thickness. A liquid prepd. by dissolving cellulose acetate in a THF solvent is further coated thereon and is dried to form a cellulose acetate film 5 having about 10mum thickness to obtain an ion selective electrode. The sensitivity and responsiveness are improved by the above-mentioned constitution and the generation of deterioration is obviated even after continuous measurement for a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ion-selective electrode and an ion sensor body that can selectively measure the concentration of specific ions.

[Technical background of the invention and its problems]

Conventionally, ion-selective electrodes have the characteristic of being able to selectively quantify the concentration of specific ions in a liquid.

Until now, it has been used in a wide range of fields such as monitoring the concentration of specific ions and analyzing water quality. This is, for example,
In the case of a cation, monoselective electrode, the relationship between the activity a+ of the target cation and the potential E shown by the cation selective electrode is E=E +2.303 (几T/ZF)tof a+
...... As in (1), in the case of an anion-selective electrode, t is between the target anion's activity ff1a- and the potential shown by the anion-selective electrode.

h=H"-2,30:1(RT/ZF)rota-
- As shown in (2), there is a proportional relationship between the logarithm of the activity and the potential. Therefore, the activity of the target ion can be easily calculated from the measured value of the potential.

In the above formulas (1) and (2), R is a gas constant, T is an absolute temperature, Z is an ionic valence, F is a gua 2 de constant, and Bo is a standard electrode potential of the system.

In this way, by using an ion-selective electrode, it becomes possible to quantify the ion concentration over a wide concentration range simply by measuring the potential. Furthermore, by using an ion-selective electrode and making the electrode part smaller, it becomes possible to measure a small amount of sample. Since the topic of ion selectivity is convenient, it has recently been used for medical purposes, particularly for ions present in blood, such as Na+,
Attempts to use it for quantifying various ions such as K+ and ct-1 are becoming more popular62.

In fact, many analysis devices using the ion-selective electrode have been devised, and their use as medical analysis devices for blood and the like is expanding.

Among these ion-selective electrodes, the most recent ion-selective electrodes have no internal electrolyte solution and have a simple structure in which an ion-sensitive membrane is formed directly on the metal. Because it's simple, it's getting a lot of attention.

In addition, as a method for continuously measuring the concentration of each of a plurality of [M ions in a liquid to be measured, a plurality of ion-selective electrodes are arranged in parallel in the flow path of the liquid to be measured.

We will analyze the electricity issues of each of them. It is known that the so-called PIr, flow cell system is convenient.

Furthermore, recently, a flow-through type ion sensor body has been developed in which the ion-selective electrode without the internal electrolyte solution is combined in an integral C niflow cell system.

In this flow-type ion sensor body, the flow path direction of the liquid to be measured is a
Therefore, since it is composed of the electrode surface of the ion-selective electrode, it has a small W; are doing.

By the way, when this flow 211m ion sensor body is used for water quality analysis such as blood, etc., the sensitivity of the ion sensor decreases because various #reservoir components are attached to the ion-sensitive membrane part formed in the flow path (2). Phenomena such as delays in response time and
These sensors have the disadvantage of causing an error in the analysis value C'. Such interference is especially caused by large molecular weight ions contained in the blood or substances containing positively or negatively charged groups, which may cause selective ions other than neutral carriers to enter the polyvinyl chloride resin membrane. This is particularly noticeable in ion-selective electrodes. This is presumed to be because the charges of ion selected substances other than neutral carriers are biased towards positive or negative, and the addition of electrostatic effects promotes the deposition of the visiting substances.

In addition, we improved the reproducibility caused by the presence of anionic minerals in urine samples using an anion-selective electrode that uses a so-called +:'l@Ps solution inside the electrode. As a means to do this, it is also possible to provide a cellulose polymer layer with a thickness of ~μm on the surface of the ion-selective membrane, as described in JP-A-55-9415.
No. 4 @ζ2 has been shown, but in practical terms it cannot be said to be redundant in terms of sensitivity, responsiveness, etc.

[Purpose of the invention]

The present invention is an ion-selective electrode that improves the sensitivity and responsiveness of the upper Hd point C double layer, enables continuous measurement over a long period of time without causing long-term deterioration, and simplifies the plate pressure. The purpose is to provide an ion senna body using this.

[Summary of the invention]

The present invention comprises: an isoelectric member to which a lead terminal for signal extraction is connected; an ion-sensitive membrane containing a polyvinyl chloride resin and an ion selective substance provided on the front surface of the isoelectric member;
Said ion sensitive! 100λ~15μm provided on the surface
Ion selection 8 with cellulose firewood 9: arranged along the electrode and the through hole drilled in the insulating resin plate so as to form at least a part of the inner circumferential surface of the through hole. an isoelectric member provided; a polyvinyl chloride resin that has been mapped at least a part of the surface of the insulating resin plate that forms a part of the inner surface of the shell through hole and a part of the surface of the conductive member; An ion-selective member C consisting of an ion-selective material C, consisting of two connected leads;
This is an ion sensor body in which the ion-selective electrodes are integrally connected to each other through an insulating member so that the respective through holes form a flow path for a liquid to be measured.

In other words, the present invention provides an ion-selective electrode in which an ion-sensitive membrane is directly provided on the surface of a conductive member as an electrode, where the ion-sensitive membrane surface t is 100λ to 15 μm.
The biggest feature of this system is that it provides a vote of -1.

The present invention will be explained in detail below.

First, the ion-selective electrode according to the present invention, as shown in FIG. A member 3 is provided, and a polyvinyl chloride resin and a fourth ion selective material are further coated on the surface of the second conductive member 3.
Via ion-sensitive J1114 containing grade ammonium salts, the film thickness ranges from 100A to 15 μm.
= living cell・-ff is provided.

The ion sensor body according to the present invention is constructed, for example, as shown in the schematic sectional view of FIG.

That is, φlla, llb, and llc in FIG. 2 represent sodium A, potassium, and chloride ion selective electrodes, respectively.

The insulating resin plates that serve as the bases of these ion-selective electrodes 11a, llb, and IIC each have a through hole 13 in the center.
a.

Polyvinyl chloride resin plate 12 with perforations 13b and 13C
a.

Consists of 12b and 12c. Also, 1 through hole 13a
, 13b.

13c I; laminated conductive member 14g adhered along
, 14b.

14C forms a part of the inner peripheral surface of the through hole.

The inner peripheral surfaces of the through holes 13a, 13b, 13c are ion sensitive wA made of polyvinyl chloride resin and each ion selective substance. 1: Selectively sensitive and generates electromotive force corresponding to ion concentration. Ion sensitive membrane 15a.

The electrical signals generated at 15b and 15c are transferred to the conductive member 14a.
, 14b , 14 (% lead wire 16a , 16b ,
16C and is led to a potential indicator system (not shown).

We talked. Reference numeral 17 indicates a reference electrode having a two-liquid end portion 18 on the inner peripheral surface C of the through holes 3a, 3b, and 3c. The electrical signal of this reference electrode is led to a potential indicating device system (not shown) via a lead wire 16d, and the difference between the reference potential of the reference electrode 17 and the potential of the ion selective electrodes 11a, llb, 110 is detected by the potential indicating device. is displayed.

These ion-selective electrodes 1a, lb, lc and reference electrode 7 are connected to their respective through holes ia via an electrically insulating member 19.
A, IAB, and IAC are integrally connected to each other to form a flow path for the liquid to be measured. Second, this ion sensor body with poor circulation has the through holes 13a, 13b,
13C and 13d, and the liquid to be measured outlet 21 and the lead wires 16a and 1.
6b, 16C, and 16d are surrounded by an exterior sheathing having an electrical signal output port & leading out to the outside.

Jun is the ion sensitive membrane 15C of the chloride ion selective electrode.
This is a cellulose acetate membrane with a thickness of 6 μm formed on the surface of

As a result of using the distributor's ion sensor body of the present invention for fixed-site analysis of ions in blood, the deterioration of the conventional chlorine ion sensor, which had a short lifespan, was suppressed, making it possible to continuously divide at least 30,000 samples. Ta.

In addition, in the above explanation, only chloride ion senna 11C is used.
Although a cloth cell was provided, other Maki's ion sensors f2 can be used as appropriate.

Note that #grass # used in the present invention; the thickness of night celluloid is 10
The reason why the range is 0λ to 15μm is that if it is less than 100%, it will be difficult to form a film in practice and it will be difficult to obtain a uniform film thickness, and if it exceeds 15μm, the response speed will be slow and the measurement will be difficult. Calibration of values is complicated and cellulose butyrate cellulose acetate butyrate, cellulose acetate propionate.

Examples include cellulose propionate and cellulose propionate, but it is preferable to use cellulose acetate as the soil.

Incidentally, the ion selective electrode with two phases of the present invention C is ha.

K", Ca", C1"-, Br-io:/I'm not doing anything wrong.

Among these, for example, monensin and crown ethers are used as Na ion selective substances; palinomycin crown ethers are used as ion selective substances, and CI! - Representative examples of ion selective substances include quaternary ammonium salts and iron phenanthroline complexes.

Among these, the ion selective one is palinomycin.

In the case of carriers other than neutral carriers such as crown ethers, for example, in the case of quaternary ammonium salts, forming a membrane such as cellulose acetate on the surface of the ion-selective membrane will cause the adhesion of interfering components in the liquid to be measured. As a result, a longer life is achieved. In particular, the thickness of the film needs to be 1008 to 15 μm for the reasons mentioned above,
Practically speaking, it is preferable to set the thickness to 0.1 μm to 10 μm.

[Embodiments of the invention]

Embodiment 1 As shown in FIG. 1, an AP wire 3' section and two environment tubes each having a diameter of 1 mm are coated with an insulator 1. Note that the tip is 0, IM
A conductive member 3 was obtained by electrolyzing in KC/ to coat the surface of the kt line with an ArC layer to form an Ae/1tCz portion 3'. A solution containing polyvinyl chloride containing a quaternary ammonium salt is applied to the surface of the conductive member 3.

By drying, an ion-sensitive JII4 made of a polyvinyl chloride resin containing 25% of quaternary ammonium salt as an ion-selective substance was formed with a film thickness of 30 ρ to 45011 m. Furthermore, IQcc'l'HF in the solvent is 0
．． Apply a solution containing No. 21 cellulose acetate.

Dry cellulose acetate EA5 with a film thickness of 10 μtn
was formed to obtain an ion-selective electrode.

After immersing this ion-selective electrode in serum with a chloride ion concentration of 10"-"M for 150 hours, chloride ions were measured multiple times, and stable measurements were possible with a response time of 10 seconds or less. The sensitivity was similar to the initial value.

Furthermore, when we measured chloride ions in serum using the ion-selective electrode, we were able to continuously analyze and measure 30,000 samples with high accuracy without having to wash them in between.

Comparative Example-1 An ion-selective electrode in which the cellulose acetate membrane 5 was not provided in Example-1 was obtained. After immersing this ion-selective electrode in serum with a chlorine concentration of 10 M for 1 hour, the chlorine ion concentration was measured multiple times, and the response time was 5.
There is a wide variation from seconds to 60 seconds, and the sensitivity is also the initial value of 5.
Only about 0% was obtained.

Furthermore, when chloride ions in the serum were measured continuously,
It was necessary to wash every hour with a washing solution containing a proteolytic enzyme in the IM NaCl solution, and even in this case, 3,000 to 20,000 samples were analyzed, and 6,111 samples were analyzed, making it unusable.

From the above Example 1 and Comparative Example 1, it is clear that by using the present invention, the life can be significantly extended and the response speed and sensitivity can be significantly improved.

Example 2 In the ion sensor body as shown in FIG.
/Arc/ After providing the electrode, the same method f as in Example-1:
From this, ion-sensitive membranes 138, 13b, 13c and cellulose acetate membranes were formed.

Next, in order to comply with the actual measurement conditions, the output from the lead wire 16C was measured when standard serum and serum having the same chloride ion concentration were sequentially flowed from the inlet to the outlet 24, as shown in Figure 3. . Note that output A is the standard solution.

B shows the serum output, respectively.

Comparative Example-2 An ion sensor body in which the cellulose acetate membrane was not provided in Example-2 was obtained. Using this ion sensor body, measurements similar to those in Example 2 were carried out, and as a result, outputs as shown in FIG. 4 were obtained.

Comparative Example 3 In Example 2, the thickness of the cellulose acetate membrane was set to 40 μm, and the same measurements as in Example 2 and Comparative Example 2 were performed, and as a result, the output as shown in FIG. 5 was obtained.

By using the present invention from the above Example-2, Comparative Example-2, and Comparative Example-3, there is no difference between the standard solution and serum (corresponding to actual measurement) (Fig. 3).

It is clear that there is no need to perform calibration during actual measurements. On the other hand, if a cellulose acetate membrane is not provided (Fig. 4), there will be a difference in the output shape between the standard solution and the serum (Fig. 4), so it is necessary to perform some kind of calibration for practical use. It is clear that there is.

Furthermore, even if a cellulose acetate membrane is provided, if the membrane thickness falls within the range of the present invention (Fig. 5), it may take a long time until the standard solution and serum exhibit similar output shapes, but reach the peak value C2. It is clear that this method cannot be put to practical use as it is, and that it is necessary to calibrate it using a calibration curve or the like based on the output value for about 10 seconds, for example.

Furthermore, it is known that the above-mentioned response speed normally becomes slower as the concentration of the ion to be measured becomes higher; however, when using the present invention, particularly at high concentrations, the response speed is remarkable. An improvement effect was obtained.

Example-3 Figure 6C used in the ion senna body of Example-2;
For a single ion selective electrode as shown.

Insulating resin plate 12I made of polyvinyl chloride: Ion-sensitive M15 and cellulose acetate Jli2 to the inner surface of the bifurcated conductive member 14
An example of the formation method of No. 4 is shown below. In the above Example C, a prescribed film was obtained by applying and drying a solution of the ion-sensitive membrane material and cellulose acetate in the usual manner, but in this example, an insulating resin plate provided with a conductive member 14 was used. 1
While rotating 2 with a spinner, the solution of ion-sensitive membrane material and cellulose acetate is dripped into the through-hole C: one member at a time, and centrifugal force is applied to the inner wall of the conductive member to form an excellent film with a uniform thickness. By drying it, the desired membrane could be obtained.Ion Senna bodies and Examples manufactured using the ion-selective electrode 11 in which an ion-sensitive membrane and a cellulose acetate membrane were formed using such a method 2
ion sensor bodies were used for actual measurements under the same conditions.
When this example was used, the measurable sample loss could be improved by about 3 ots compared to Example-2.

As is clear from this result, it is more preferable to form the ion-sensitive membrane and cellulose acetate membrane in the ion sensor body as shown in FIG. 2 by using rotation with a spinner or the like or centrifugal force.

Example 4 After forming an ion-sensitive film with a thickness of 30 μm on the surface of the conductive member consisting of the A,y/mutCl electrode in Example-1.

Further, polyvinyl chloride resin and cellulose acetate were mixed at an IT ratio of 1:1, and a 5 μm cellulose acetate film was formed via an interlayer film containing 25% of quaternary ammonium salt.

The ion-selective electrode obtained in C2 was stirred in serum as the liquid to be measured for 100 hours (at room temperature), and then chloride ions were measured. As a result, results similar to the initial values were obtained. .

In comparison with C2, the same ion-selective electrode was used except that the interlayer film was not provided, and the chloride ion concentration was measured after stirring in serum for 5 hours (at room temperature). This result output is the initial value 6
The voltage decreased to about 40 mV compared to 0 mV.

Peeling of the cellulose acetate membrane, elution of the ion-selective substance, etc. may be the cause of this decrease in output, but it is not necessarily clear.

As a result, it is clear that the life of the ion-selective electrode can be further improved by providing the above-mentioned intermediate film C2 between the ion-sensitive membrane and the cellulose acetate membrane.

〔Effect of the invention〕

As is clear from the above results, by using the ion-selective electrode and ion sensor body according to the present invention, sensitivity and capacity are improved, and measurements can be carried out continuously for a long period of time without causing long-term deterioration. Calibration can be simplified.

[Brief explanation of drawings]

Figure W & 1 is a sectional view showing an example of the configuration of the ion selective polarizer according to the present invention, Figure 2 is a sectional view showing an example of the configuration of the ion sensor body according to the present invention, Figures 3, 4 and 5. The figure shows an example of the characteristics of an ion senna body. FIG. 6 is a perspective view showing an example of the configuration of an ion-selective electrode used in the ion sensor body C2. 3114, x4a, 14b, 14C--Conductive member representative Patent attorney Kensuke Norichika (and 1 other person) Figure 1/2A 121. 12C/7 2'3 Figure 3 Figure 4 Figure 5 Figure 6 Procedure amendment (voluntary) Showa, Furnace 9. Iku Japan Patent Office Commissioner 1, Indication of the case Japanese Patent Application No. 59-57310 2, Name of the invention Ion-selective electrode and ion sensor body 3, Person making the amendment Relationship with the case Patent applicant (307) Toshiba Corporation 4. Agent Address: 1-1 Shibaura-chome, Minato-ku, Tokyo 105 Description Full text and drawings 6. Details of amendments Document 1. Name of the invention Ion selective electrode and ion sensor body 2. Scope of claims 1) A conductive member to which a lead terminal for signal extraction is connected,
It is characterized by comprising an ion-sensitive membrane containing a polyvinyl chloride resin and an ion-selective substance provided on the surface of the conductive member, and a 100X-15 μm cellulose ester membrane provided on the surface of the ion-sensitive membrane. Ion selective electrode. 2) The ion-selective electrode according to claim 1, characterized in that the cellulose acetate is made of cellulose acetate. 3) The ion-selective electrode according to claim 1, characterized by an ion-sensitive membrane and a cellulose ester membrane. 4) a conductive member disposed along the through hole bored in the insulating resin plate so as to form at least a part of the inner peripheral surface of the through hole; and a conductive member forming the inner surface of the through hole. an ion-selective membrane consisting of a member surface and the conductive member surface; a 100X-1 s μm cellulose ester membrane provided on the ion-sensitive membrane surface; and a lead wire connected to the conductive member. An ion sensor body comprising at least one ion selective electrode, the through holes of which are integrally connected to each other via an insulating member so as to form a flow path for a liquid to be measured. 5) The ion sensor body according to claim 4, characterized in that cellulose acetate is used as the IiO cellulose ester. 6) The ion according to claim 4, characterized in that an intermediate film containing a polyvinyl chloride resin, a cellulose ester, and an ion selective substance is provided between the ion-sensitive membrane and the cellulose ester membrane. Senna body. 3. Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an ion-selective electrode and an ion sensor body that can selectively measure the concentration of specific ions. [Technical background of the invention and its problems] Ion-selective electrodes have a conventional feature of being able to selectively quantify the concentration of specific ions in a liquid. Until now, it has been used in a wide range of fields such as monitoring the concentration of specific ions and analyzing water quality. This is an example of
In the case of an anion-selective electrode, the relationship between the activity a+ of the target cation and the potential E exhibited by the cation-selective electrode is E=E0+2.303(RT/ZF)loga+ −・
-・-・(1) Ω In addition, in the case of an anion-selective electrode, there is a relationship between the activity a- of the target anion, ion and the potential shown by the anion-selective electrode. =E0-2.303(RT/ZF)loga---...
12), the logarithm of the activity is proportional to the potential, so the activity of the target ion can be easily calculated from the measured value of the potential. In the above tU equation and equation (2), R is a gas constant, T is an absolute temperature, 2 is an ion valence, F is a Faraday constant, and EO is a standard electrode potential of the system. In this way, by using an ion-selective electrode, it is possible to quantify ion concentration over a wide concentration range simply by measuring the potential. Furthermore, by using an ion-selective electrode and making the electrode part smaller, it becomes possible to measure a small amount of sample. Thus, ion-selective electrodes. Since it is convenient, recently there have been many attempts to use it for medical purposes, especially for quantifying various ions present in blood, such as % Na+eK+HC1-r.
In fact, many types of analyzers using the ion-selective electrodes have been devised, and their use as medical analyzers for blood and the like is expanding. Among these ion-selective electrodes, recently, ion-selective electrodes with a simple structure in which an ion-sensitive membrane is formed directly on a metal without an internal electrolyte solution have become particularly popular. The electrodes are attracting attention because they are easy to manufacture, handle, and maintain. Furthermore, as a method for continuously measuring the concentration of each of a plurality of types of ions in a liquid to be measured, a plurality of ion-selective electrodes are arranged in parallel in the flow path of the liquid to be measured. It is known that the flow cell method, which analyzes electrical signals from each electrode, is convenient. Furthermore, recently, a flow-type ion sensor body has been developed in which the ion-selective electrodes having no internal electrolyte solution are integrally connected in a flow cell manner. This flow-type ion sensor body is compact and multifunctional because the flow path surface of the liquid to be measured is made up of the electrode surfaces of multiple ion-selective electrodes, and the amount of liquid to be measured required for ion analysis is small. It has the advantage of being sufficient. By the way, when this flow-type ion sensor body is used for water quality analysis such as blood, etc., various interfering components adhere to the ion-sensing waist formed in the flow path, resulting in a decrease in the sensitivity of the ion sensor and a delay in response time. This phenomenon occurs, and there is a problem in that errors occur in the analytical values obtained by these sensors. Such interference is especially caused by large molecular weight anions contained in blood, etc., or substances with positively or negatively charged groups. This is noticeable in ion-selective electrodes. This is presumed to be because the charges of ion selective substances other than neutral carriers are biased toward positive and positive, and the adhesion of the above-mentioned obstructions is promoted due to the addition of electrostatic action. In addition, as a means of improving the poor reproducibility caused by the anionic organic components that are often contained in urine samples using so-called anion-selective electrodes that use an electrolyte inside the electrode, a thick layer is added to the surface of the ion-selective membrane. Although JP-A-55-94154 discloses the provision of a cellulose polymer membrane with a thickness of 30 to 50 .mu.m, it is not considered to be sufficient in terms of sensitivity, responsiveness, etc. in practice. [Object of the Invention] In view of the above points, the present invention provides an anion-selective electrode that significantly improves sensitivity and response, allows continuous measurement over a long period of time without deterioration, and simplifies calibration. The purpose is to provide an ion senna body using the following methods. [Summary of the Invention] The present invention provides a conductive member to which a lead terminal for signal extraction is connected, an ion-sensitive membrane containing a polyvinyl chloride resin and an ion-selective substance provided on the surface of the conductive member, and a An ion selective electrode equipped with a cellulose ester membrane of ~15 μm provided on the membrane surface, and at least a part of the inner circumferential surface of the through hole formed along the through hole bored in the insulating resin plate. a polyvinyl chloride resin and an ion selector that coat at least a portion of the surface of the conductive member forming the inner surface of the through hole and the surface of the insulating resin plate adjacent to the surface of the conductive member; The ion-selective electrode includes at least one ion-selective electrode consisting of an ion-sensitive membrane made of a substance, a cellulose ester membrane of 100X to 15 μm provided on the surface of the ion-sensitive membrane, and a lead wire connected to the conductive member. The ion sensor is an ion sensor body in which the sexual electrodes are integrally connected to each other through an insulating member, and the through holes thereof form a flow path for the liquid to be measured. In other words, the present invention is an ion-selective electrode in which an ion-sensitive membrane is directly provided on the surface of a conductive member serving as an electrode, and the main feature of the present invention is that a cellulose ester membrane of 10X to 15 μm is provided on the surface of the ion-sensitive membrane. . The present invention will be explained in detail below. First, the ion-selective electrode according to the present invention, as shown in a schematic cross-sectional view in FIG. 1 is provided on the surface of the conductive member 3 via an ion sensitive membrane 4 containing a polyvinyl chloride resin and a quaternary ammonium salt as an ion selective substance.
A cellulose ester membrane having a thickness in the range of ooX to 15 μm is provided. Next, the ion sensor body according to the present invention is constructed, for example, as shown in a schematic cross-sectional view in FIG. That is, lla, llb, and llc in FIG. 2 represent sodium and chloride ion selective electrodes, respectively. The insulating resin plates that serve as the bases of these ion-selective electrodes 11a, 11b, and 11c all have through holes 13a and 13b in the center.
. Polyvinyl chloride resin plates 12a, 12 with holes 13c perforated therein
b and 12c. In addition, through holes 13a and 13b
, 13c, annular conductive members 14a, 1
4b and 14c form part of the inner peripheral surface of the through hole. Ion sensitive membranes 15a, 15b, 15c made of polyvinyl chloride resin and respective ion selective substances provided on the inner peripheral surfaces of the through holes 13a, L3b, 13c are connected to the through holes 13a.
, 13b, 13c selectively respond to each ion in the liquid to be measured, and generate an electromotive force corresponding to the ion concentration. The electrical signals generated in the ion sensitive membranes 15a, 15b, 15c are transferred to the conductive members 14a, 14b, 14c lead wires 16a, 1.
6b and 16c, it is led to a potential indicating device system (not shown). Further, reference numeral 17 indicates a reference electrode having a liquid junction portion 18 on the inner circumferential surface of the through holes 13a, 13b, and 13c. The electric signal of this reference electrode is led to a potential indicating device system (not shown) through a lead wire 16d, and the difference between the reference potential of the reference electrode 17 and the potential of the ion selective electrodes 11a, llb, and lie is detected by the potential indicating device. Is displayed. These ion-selective electrodes 11a, llb, l'lc and reference electrode 17 are integrally connected to each other through an electrically insulating member 19 so that their respective through holes 13a, 13b, 13c form a flow path for the liquid to be measured. is connected to. Furthermore, this flow type ion sensor body has a core through hole 13a. Measured liquid inlet 2 connected to 13b, 13c and 13d
0, the liquid to be measured outlet 21, and the lead wire 16a. It is surrounded by an exterior 23 having an electrical signal output port 22 for leading the signals 16b, 16c and 16d to the outside. 24 is the ion sensitive membrane 15c of the chloride ion selective electrode.
This is a cellulose acetate film with a thickness of 6 μm formed on the surface of As a result of using the flow-type ion sensor body of the present invention for quantitative analysis of ions in blood, the deterioration of chloride ion senna, which conventionally had a short lifespan, was suppressed, making it possible to continuously analyze at least 30,000 samples. . In the above description, the cellulose acetate membrane 24 was provided as a cellulose ester membrane only in the chlorine ion sensor ie, but it can be used in other types of ion sensors as appropriate. Note that the thickness of the cellulose ester membrane used in the present invention is 10
The reason for setting the value to 0K-1 sμm is that if it is less than too This is because calibration becomes complicated. The cellulose ester membrane can be selected as appropriate and includes cellulose butyrate, cellulose acetate phthalate, cellulose acetate globionate, cellulose globionate, etc., but ink using cellulose acetate is practically preferred. Note that the ion selective electrode used in the present invention includes Na'',
Examples include K", Ca", Cl-, Br-1 on sensors, and the like. Among these, for example, Na+ ion selective substances include monensin and crown ethers; A typical example is the phenanthroline complex. Among these, when the ion-selective material is other than neutral carriers such as palinomycin crown ethers, for example, quaternary ammonium salts, it becomes noticeable when a film such as cellulose acetate is formed on the surface of the ion-sensitive membrane. As a result of suppressing the adhesion of interfering components in the liquid to be measured, a longer life is achieved. In particular, the thickness of the film is 10% due to the reasons mentioned above.
It needs to be 0X-15μm, and in practice it is 0.1μm.
It is preferable to set it to 10 micrometers. An interlayer film made of a polyvinyl chloride resin and a cellulose ester, or an interlayer film containing a polyvinyl chloride resin and a cellulose ester roughly containing an ion selective substance is provided between the ion-sensitive membrane and the cellulose ester membrane. It is preferable. This interlayer film improves the adhesion between the ion-sensitive membrane and the cellulose ester membrane, resulting in more stable electrode operation even under vigorous stirring during measurement. On the other hand, even if a cellulose ester is simply applied to an ion-sensitive membrane, a portion of the ion-sensitive membrane falls off in a solvent in which the cellulose ester is dissolved, thereby forming an intermediate film-like substance. However, the intermediate film-like material obtained in this way has an insufficient film thickness, and the adhesion effect as described above can hardly be obtained. Therefore, it is desirable to provide the above-mentioned intermediate film between the ion-sensitive membrane and the cellulose ester group. The thickness range of this intermediate film is preferably 100L-15/Am, and more preferably
Preferably, the thickness is from μm to 5 μm. If it is thinner than this range, the above-mentioned adhesion effect cannot be obtained, and if it is thicker, the response speed of the electrode will be reduced. The specific composition of this intermediate layer is 1, for example, 50wt% polyvinyl chloride + 5% cellulose acetate.
0 wt%, '6 or polyvinyl chloride 35 wt To
+ Cellulose acetate 35wt% + Ion selective substance 3
Examples include 0wt%. [Embodiments of the invention] Example-1 As shown in Fig. 1, the connection of diameter 1 +w+a is made of sandy Ag.
The portion 3' is coated with an insulator l such as empire arch. By electrolyzing the tip in 0.1 MKC6, the b-line surface is coated with Ag (J layer) to form Ag CJ part 3'' in total, and from this Ag part 3' and Ag C1 part 3''. A conductive member 3 was obtained.A solution containing polyvinyl chloride containing a quaternary ammonium salt was applied to the surface of the conductive member 3 and dried to obtain a conductive member 3 containing 25% of quaternary ammonium salt as an ion selective substance. The ion-sensitive membrane 4 made of polyvinyl chloride resin has a thickness of 300 to 450 μm.
It was formed with a film thickness of . Furthermore, a solution of 0.2 g of cellulose acetate dissolved in 10 cc of THF solvent was applied and dried to a film thickness of 10 μm.
A cellulose acetate membrane 5 was formed to obtain an ion-selective electrode. After immersing this ion-selective electrode in serum with a chloride ion concentration of 10-2M for 150 hours, chloride ions were measured multiple times. The response time was less than 10 seconds, and stable measurements were possible. The sensitivity was similar to the initial value. Furthermore, when we measured chloride ions in serum using the ion-selective electrode, we were able to continuously analyze and measure 30,000 samples with high accuracy without having to wash them in between. Comparative Example-1 An ion-selective electrode in which the cellulose acetate membrane 5 was not provided in Example-1 was obtained. After immersing this ion-selective electrode in serum with a chlorine concentration of 10-2M for 1 hour, we measured the chlorine ion concentration multiple times, and found that the response time varied greatly from 5 seconds to 60 seconds, and the sensitivity was also lower than the initial value. I only got about 50 pieces. Furthermore, when chloride ions in the serum were measured continuously,
It is necessary to wash with a washing solution containing proteolytic enzymes in IM NaCl solution every hour, and even in this case,
After analyzing and measuring 000 to 20,000 samples, it became unusable. It is clear from the above Example-11 and Comparative Example-1 that by using the present invention, the life span can be significantly extended and the response speed and sensitivity can be significantly improved. Example 2 In the ion cell body as shown in FIG.
After providing the C11 electrode, ion m-compatible WAs 13a, 13b, 13c and cellulose acetate film 24 were formed in the same manner as in Example-1. Next, in order to conform to the actual measurement conditions, the output from the lead wire 16c was measured when a standard solution and serum having the same chloride ion concentration were sequentially flowed from the inlet 20 to the outlet 24, as shown in FIG. Note that the output A indicates the standard solution, and the output B indicates the serum output. Comparative Example-2 An ion senna body in which the cellulose acetate film 24 was not provided in Example-2 was obtained. Using this ion sensor body, measurements similar to those in Example 2 were carried out, and as a result, outputs as shown in FIG. 4 were obtained. Comparative Example 3 In Example 2, the thickness of the cellulose acetate film 24 was set to 40 μm, and the same measurements as in Example 2 and Comparative Example 2 were performed, and as a result, the output as shown in FIG. 5 was obtained. By using the present invention from the above Example-2, Comparative Example-2, and Comparative Example-3, there is no difference between the standard solution and serum (corresponding to actual measurement) (Figure 3). It is clear that there is no need to perform calibration during actual measurements. On the other hand, if the cellulose acetate membrane is not provided (Figure 4), there will be a difference in the output shape between the standard solution (4) and serum (6), so it is necessary to perform some kind of calibration in practical use. The thing is clear. Even if a cellulose acetate membrane is provided, if the thickness of the membrane falls within the range of the present invention (Figure 5), the standard solution and serum may exhibit similar output shapes, but may be heated for a long time until reaching the peak value. It is obvious that it cannot be put to practical use because of the required time, and that it is necessary to calibrate using a calibration curve or the like from an output value of about 10 seconds, for example. Furthermore, it is known that the response speed as described above normally becomes slower as the ion concentration to be measured becomes higher, but when the present invention is used, a remarkable response improvement effect is achieved especially at high concentrations. Obtained. Example-3 Regarding the single ion-selective electrode as shown in FIG. 6 used in the ion sensor body of Example-2, the inner surface of the through hole drilled in the insulating resin plate 12 made of polyvinyl chloride was Ion sensitive membrane 1 on the inner surface of the conductive member 14 provided
5 and an example of the method for forming the cellulose acetate film 24 will be shown. In the above embodiment, a prescribed film was obtained by applying and drying a solution of the ion-sensitive membrane material and cellulose acetate in the usual manner, but in this embodiment, the conductive member 1
While rotating the insulating resin plate 12 provided with No. 4 using a spinner, solutions of the ion-sensitive membrane material and cellulose acetate were sequentially dropped into the through holes. A film of uniform thickness and excellent adhesion was formed on the inner wall of the conductive member by centrifugal force, and by drying, the desired film could be obtained. Ion-selective electrode 1 in which an ion-sensitive membrane and a cellulose acetate membrane were formed using such a method
When the ion sensor body manufactured using Example 1 and the ion sensor body of Example-2 were used for actual measurement under the same conditions, one test was carried out. was able to improve by about 30 points. As is clear from this result, it is more preferable to form the ion-sensitive membrane and cellulose acetate membrane in the ion sensor body as shown in FIG. 2 by using rotation with a spinner or the like or centrifugal force. Example 4 After forming a 30 μm ion-sensitive film on the surface of a conductive member made of Ag/AgC1 electrodes in Example 1, polyvinyl chloride resin and cellulose acetate were further added to the surface of the conductive member.
:1 weight ratio, and further added 2 as an ion selective substance.
A cellulose acetate film of 5 Itm was formed via an interlayer film containing 5 Itm of quaternary ammonium salt. The ion-selective electrode thus obtained was stirred in serum as a liquid to be measured for 100 hours (at room temperature), and then chloride ions were measured. As a result, results similar to the initial values were obtained. In comparison, using the same ion-selective electron i except that the interlayer film was not provided, the chloride ion concentration was measured after stirring in serum for 25 hours (at room temperature). This result output is the initial value 6
Compared to 0mV, it decreased to about 40mV. Peeling of the cellulose acetate membrane, elution of the ion-selective substance, etc. are thought to be the cause of this decrease in output, but it is not always clear. As a result, it is clear that the life of the ion-selective electrode can be further improved by providing the above-mentioned intermediate film between the ion-sensitive membrane and the cellulose acetate membrane. [Effects of the Invention] As is clear from the above results, by using the ion-selective electrode and ion sensor body according to the present invention, the sensitivity and response are improved, and the sensor can be used continuously for a long period of time without causing long-term deterioration. calibration can be simplified. 4. Brief Description of the Drawings FIG. 1 is a cross-sectional view showing an example of the configuration of an ion-selective electrode according to the present invention. FIG. 2 is a cross-sectional view showing an example of the configuration of an ion sensor body according to the present invention. FIG. 3, FIG. 4, and FIG. 5 are diagrams showing characteristic examples of an ion sensor body, and FIG. 6 is a perspective view showing a configuration example of an ion selective electrode used in the ion sensor body. 3, 14a, 14b, 14c - Conductive member 4, 15
a, 15b, 15cm-・Ion sensitive membrane 5I24...
Cellulose acetate membrane agent Patent attorney Nori Chika
Yuu

Claims (1)

[Claims] 1) A conductive member to which a lead terminal for signal extraction is connected;
A patent characterized in that a polyvinyl chloride resin and an ion selective substance are provided on the surface of the conductive member; An ion selective electrode according to claim 1. 3) The ion-sensitive membrane is provided with an interlayer film containing an ion-selective substance and an ion-selective substance. The ion-selective properties described. 4) Along the through holes drilled in the insulating resin plate. a conductive member disposed to form at least a part of the inner peripheral surface of the through hole; at least a surface of the conductive member forming the inner surface of the through hole and a surface of an insulating resin plate adjacent to the surface of the conductive member; An ion-sensitive membrane made of partially coated polyvinyl chloride resin and an ion-selective material, and an X of 100 A to 15 μm provided on the surface of the ion-sensitive membrane.
It includes at least one ion-selective electrode consisting of a cello I stage -4 and a lead wire connected to the conductive member C. 5. The ion sensor body according to claim 4, characterized in that the ion sensor body uses an irose, which is characterized by being integrally connected to each other to form a flow path for the measurement liquid. 6) Between the ion-sensitive membrane and the cellulose, an interlayer film containing an ion-selective substance made of polyvinyl chloride resin is provided. An ion senna body according to claim 4, characterized in that: