JPS62200260A - Ion selective electrode apparatus - Google Patents

Abstract

PURPOSE:To enable the detection of ion density in an electrically stable state without being affected by any external factor, by arranging metal bodies on both sides of an electrode section to be both commonly earthed with each hole formed at the center thereof facing a passage path. CONSTITUTION:Holes 12A and 12B with the diameter thereof the same as respective fine-dia. Holes are drilled in a metal body 9A containg a flange 9C and a metal body 9B containing a flange 9D respectively to form a passage path for a sample liquid. Either the flange 9C or 9D is used as an inlet port of the sample liquid while the other as an outlet port thereof. Even in case the sample liquid spills somewhere besides than this apparatus and breaks the insulation of a box body or the like f the sample there, any accompanied change in the potential of the sample liquid will be abosorbed by the metal body 9A or the metal body 9B. In other words, the sample liquids in both the passages are maintained at the ground potential at the part where they comes in contact with the metal bodies 9A and 9B and hence, the potential held by ions in the sample liquids within the apparatus is free from variations other wise caused by an an external factor thereby enabling the detection of ions in a stable condition.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to an ion-selective electrode device that is used in a flow-type ion analyzer and is capable of detecting ion concentration.

(Prior Art) The one shown in FIG. 4 is conventionally known as an ion-selective electrode device used in a flow-type ion analyzer.

This ion-selective electrode device has a plurality of electrode pieces 21 in a block 20 provided with a flow path 22 through which a sample liquid can flow.
are attached while being insulated from each other, and an ion-selective electrode 23 is provided at the end of each electrode piece 21 on the flow path 22 side.

Such ion-selective electrode devices have the following problems.

That is, if the insulation state of the sample liquid in the flow path 22 of this device fluctuates for some reason, that is, if the sample liquid spills in another part other than this device, for example, onto the casing, the insulation in that part is destroyed. In this case, the problem is that the influence extends to the ion-selective electrode 23 of this device, and the detection signal of this ion-selective electrode 23 becomes unstable.

(Problems to be Solved by the Invention) As described above, in the conventional device, since the device itself is not grounded, there is a drawback that the stability of the detection signal of the ion-selective electrode is impaired by external factors.

Therefore, an object of the present invention is to provide an ion-selective electrode device that can detect ion concentration in an electrically stable state without being influenced by external factors.

"Structure of the Invention" (Means for Solving Problems) The ion-selective electrode device of the present invention includes a plate-like base formed of an insulating material having a small hole in the center, Each small hole has a plurality of electrodes each having a conductive layer formed on the inner circumferential surface and both sides of the plate-like substrate, and an ion-sensitive layer formed on at least the conductive layer on the inner circumferential surface of the small hole. An electrode part is constructed by electrically insulating and connecting and covering each other so as to form a channel, and a hole is provided on both sides of the electrode part, both of which are commonly grounded and formed in the center with respect to the flow path. It is made by arranging metal objects facing toward each other.

(Function) In the ion-selective electrode device having the following configuration, the ion concentration of the sample liquid detected by the ion-sensitive layer of this device is sent out as an electrical signal from the electrode, and is transmitted by the circuit system connected to this device. Signal processed. Both metal bodies provided on both sides of the electrode part are commonly grounded, and
Since the hole provided in the center of these holes is in contact with the sample liquid, the potential of the sample liquid in this part is maintained at the ground potential.

Therefore, even if the sample liquid spills onto the casing or breaks the insulation of the sample liquid anywhere other than this device, the electrical influence will be absorbed by this metal body and will not affect the sample liquid inside this device. . Therefore, this device allows stable detection of ion concentration.

(Example) Examples of the present invention will be described in detail below.

FIG. 1 shows a first embodiment of the present invention.

This ion-selective electrode device includes a donut plate-shaped base 1 made of an insulating material and having a small hole in the center, a conductive layer 2 formed on both sides of the base 1 and the inner peripheral surface of the small hole, and A plurality of, for example, four, electrodes 4A, 4B, 4 each having an ion-sensitive layer 3 formed on a conductive layer 2 formed on the inner peripheral surface of the hole.
C, 4D, and each electrode/IA, 48.4G, 4D, a plurality of donut plate-shaped holes disposed in contact with both sides of the electrodes/IA, 48.4G, and 4D, each having a small diameter hole approximately the same diameter as that of the donut plate-shaped base body, for example. Five insulating plates 5 and the four electrodes 4A, 4f3, 4C
, 4D and five insulating plates 5 arranged alternately so that their small diameter holes coincide with each other are sandwiched and integrated from both sides on the axis, and further the above-mentioned thin holes are placed on both sides of the outermost insulating plate 5. A holding plate 7 having a small diameter hole similar to the diameter hole formed in the center.
A and 7B are arranged in a pair to form an electrode part 10, and the outer surfaces of both holding plates 7A and 7B of this electrode part 10 are each coated with a metal material having excellent chemical resistance and corrosion resistance, such as gold or platinum. , silver, stainless steel, carbon, etc.) 9a.

9b are integrally attached, and the metal bodies 9A and 9B are commonly grounded by a grounding wire 11.

For example, one of the four electrodes 4A, 4B, 4G, and 4D
The electrode 4A is a comparison electrode, and the other three electrodes 48.
4G and 4D are respectively cheap ions such as Na÷, K
+, (This is an ion-selective electrode that detects J'-.

The base 1 constituting each of the electrodes 4A, 4B, 4C, and 4D is, for example, a donut plate in which the inner diameter of the small hole is about 1#, the diameter to the outer periphery is about 10 m, and the thickness is about 1.5 M. It is made of insulating material.

As the insulating material, Bakelite, phenolic resin, epoxy resin two-paper epoxy mixture, glass epoxy mixture, ceramic, etc. can be used.

The conductive layer 2 constituting each electrode 4A, 4B, 4C, 4D is
For example, metal oil adhesion, electroless plating.

It can be formed by ion blasting, vapor deposition, etc., and in particular, it can be easily formed by using the pudding mill wiring board production technique used for electronic circuits and the like. Examples of the metal forming the conductive layer 2 include platinum, gold, silver,
Copper or the like can be used, and the conductive layer 2 is made of a first layer of copper formed on the surface of the donut plate-shaped substrate 1 and a second layer of gold or silver formed on the surface of the first layer. J: Yes, even if it has a two-layer structure. Further, when the electrode is a reference electrode, the surface of the conductive layer 2 is preferably made of at least silver chloride.

Therefore, when silver is used as the conductive layer 2 of the comparison electrode, silver chloride is precipitated on its surface by an electric field, and when the conductive layer 2 is made of a material other than silver, such as copper, platinum, gold, etc. Preferably, these metal surfaces are coated with silver by plating, ion blating, vacuum deposition, etc., and then silver chloride is precipitated on the silver surfaces by an electric field or the like.

The ion sensitive layer 3 in the comparison electrode 4A can be formed, for example, as follows. That is, a suspension obtained by grinding the crystals and mixing 29 parts of finely powdered potassium chloride, 7 parts of polyvinyl chloride, and 64 parts of tetrahydrofuran is applied to the surface of the conductive layer 2 containing silver and silver chloride. After coating, a potassium chloride-containing film is formed by evaporating and removing tetrahydrofuran, and then, as a protective film, a tetrahydrofuran solution of polyvinyl chloride is applied to the surface of the potassium chloride-containing film and tetrahydrofuran is applied. By evaporating and removing it, a polyvinyl chloride film is formed.

The ion-sensitive layer 3 in the ion-selective electrodes 4B, 4C, and 4D can be formed, for example, as follows.

When the ion selective electrode 4B is a chloride ion electrode, 1.8 to 2.3 parts of methyl tridodecylammonium chloride and 6.7 to 7 parts of polyvinyl chloride are applied to the surface of the conductive M2.
By applying a solution consisting of 2 parts and 91 parts of tetrahydrofuran, and then evaporating and removing the tetrahydrofuran, a chloride ion sensitive layer 3 having a constant thickness can be formed.

When the ion selective electrode 1IIC is a potassium ion electrode, 0.2 to 0.5 palinomycin is added to the surface of the conductive layer 2.
1 to 4.5 to 5.0 parts, a plasticizer such as dioctyl adipe.
4 parts of polyvinyl chloride, 3.7-4.5 parts of polyvinyl chloride and 89.7-91.7 parts of tetrahydrofuran, and then removing the tetrahydrofuran.
The potassium ion sensitive layer 3 having a certain thickness can be formed.

When the ion-selective electrode 4C is a sodium ion electrode, the surface of the conductive layer 2 is coated with 0.2 to 0.5 parts of monesin, 4.5 to 5.4 parts of a plasticizer such as dioquidyl adipate, and 3 parts of polyvinyl chloride. Forming a sodium ion sensitive layer 3 having a certain thickness by applying a solution consisting of .7 to 4.5 parts and 89.7 to 91.7 parts of tetrahydrofuran, and then removing the tetrahydrofuran. I can do it.

The insulating plate 5 can be formed of the same insulating material used for the base 1 forming the electrodes 71A, 4B, =IC, 4D. Further, the insulating plate 5 includes each electrode 4A, 4B, 4C,
Used to insulate 4D from each other.

In FIG. 1, 8A, 8B, 8C, and 8D are lead wires, and each electrode 4A, 4B.

= It is electrically connected to each conductive layer 2 by solder or the like in order to take out the electromotive force generated by the IC and 4D.

Further, in FIG. 1, 90 and 9D indicate a pair of flange portions formed at the center portions of the metal bodies 9A and 9B, respectively, and the metal bodies 9A and 7 including this flange portion 9C.
Holes 12A and 12B having the same diameter as the small diameter hole are respectively formed in the metal body 9B including the flange portion 9D to form a flow path for the sample liquid. And flange part 9C.

One of 9D is used as an inlet for the sample liquid, and the other is used as an outlet for the sample liquid.

According to the ion-selective electrode device 10 having the above configuration, the sample liquid spills into the casing etc. not shown in FIG. 1 in other parts other than this device, and the insulation of the sample with respect to the casing etc. is broken at that part. Even if a situation occurs, the resulting fluctuation in the potential of the first liquid is absorbed by the metal body 9A or the metal body 9B.

In other words, since the sample liquid in the inner passage is held at the ground potential at the portions in contact with the metal bodies 9A and 9B, the potential held by each ion in the sample liquid in this device does not fluctuate due to external factors. , This allows each ion to be detected in a stable state.

In addition, since the three types of ion-sensitive layers 3 and the reference electrode 4A are exposed in the flow path formed by the small diameter hole, Na'', K ”
, (J'-) can be detected.

Since the volume of the flow path formed by the narrow holes is configured to be small, ions can be suitably detected even in a minute amount of sample liquid. Roughly speaking, the insulating plate 5 made of an insulating material and the donut plate-shaped base 1 function as a heat insulating material, so they prevent the temperature of the sample liquid from dropping during ion detection, allowing accurate analysis at all times under the temperature. can do. The function of preventing this deterioration in texture cannot be achieved when the white body of the base body 1 is made of metal. Also, electrode 4A, /IS.

Since 4G and 4D can be easily manufactured using printed wiring board manufacturing technology, the ion selective electrode device can be manufactured at low cost.

Next, the other side of the embodiment of the present invention will be explained with reference to FIG. In the ion-selective electrode device shown in the figure, parts having the same functions as those shown in FIG. 1 are denoted by the same reference numerals, and detailed explanation thereof will be omitted. The difference between this device and the device shown in FIG.
In addition, metal bodies 9E and 9F having a hole with the same diameter as the small hole in the center are integrally arranged, and these are connected to the ground wire 11.
The holding plates 7C, 7D have 7 flange portions 7E, 7F on both sides of the metal bodies 9F, 9F.
This means that they are integrally installed.

The metal body 9E can also be produced by a device having such a configuration.

Since 9F functions in the same way as metal bodies 9△ and 9B shown in Figure 1, each ion can be detected in a stable state like the device shown in Figure 1, and other functions are also shown in Figure 1. It can be equivalent to the device.

Next, an outline of the circuit system 20 for processing the detection signal of each ion detected by each of the apparatuses of the above embodiments will be explained with reference to FIG.

This circuit system 20 includes a first signal processing unit 2 that processes a detection signal @ (analog signal) from the ion-selective electrode device.
1, and a second signal processing section 22 that further processes the output signal of the first signal processing section 21.

The first signal processing section 21 includes a comparison signal amplifier 23 to which the lead wire 8A is connected, and the lead wires 88.8C, 88.
Ion signal amplifier 2 to which D is connected respectively = IA,
24B, 2=IC and the output signal of the comparison signal amplifier 23 as one input signal, respectively, to the ion signal amplifier 2/IA.

24B and 24C as input signals of the other, compare them, and send out the comparison results. Second. Third comparator 25A, 25B, 25
C and each of these comparators 25A.

The first. Second. Third isolation amplifier (isolation amplifier >26A, 2
It is equipped with 6B and 26G. In addition, in FIG. 3, these isolation amplifiers 26A, 26B, 26G
a part of each is included in the first signal processing unit 21 side,
The remaining portions of each are shown separately so as to be included on the second signal processing section 22 side. This corresponds to the fact that each of the isolation amplifiers 26A, 26B, and 26C has an internally electrically isolated structure (for example, a transformer). Further, the grounding system of each element of the first signal processing section 21 is connected to the grounding system of the ion-selective electrode device.

The second signal processing unit 22 includes buffer 7 amplifiers 27A, 278° 270 that amplify the output signals of the isolation amplifiers 26A, 26B, and 26G, respectively, and these buffer amplifiers 27A, 27B.

27C, and a changeover switch 28 that selects and sends out one of the output signals, and the grounding system of the second signal processing section 22 is connected to the first signal. Separately from the grounding system of the processing unit 21, it is grounded to, for example, a casing (not shown). The output signal of this second signal processing section 22 is sent to a display means (not shown) or the like.

According to the circuit system 20 having such a configuration, the first. Since the grounding systems of the second signal processing section 21 and 22 are separate and independent, even if a failure or the like occurs in each element on the second signal processing section 22 side, the effect will not affect the ion selective electrode device. It has the advantage of not being

It goes without saying that the present invention is not limited to the embodiments described above, and that various modifications can be made within the scope of the invention.

[Effects of the Invention] As detailed above, according to the present invention, the electrical influence of external factors occurring in parts other than this device can be absorbed by the metal body, and the ion concentration can be detected in a stable state. It is possible to provide an ion-selective electrode device that can.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway perspective view showing an embodiment of the device of the present invention, Fig. 2 is a partially cutaway sectional view showing the other side of the embodiment of the device of the present invention, and Fig. 3 shows a detection signal of the embodiment device. A circuit diagram showing a processing circuit system, and FIG. 4 is a schematic cross-sectional view of a conventional device. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Conductive layer, 23... Ion sensitive layer, 4Δ, 4B, 4C, 4D... Electrode, 9A, 98
．． 9F, 9F...Metal body, 10... Electrode part.

Claims (2)

[Claims] (1) A plate-shaped substrate formed of an insulating material having a small hole in the center, an inner peripheral surface of the small hole of this plate-like substrate, a conductive layer formed on both sides of the plate-shaped substrate, and at least the inner periphery of the small hole. An electrode section is constructed by connecting a plurality of electrodes having an ion-sensitive layer formed on a conductive layer on the surface while electrically insulating each other so that each small diameter hole serves as a flow path for the sample liquid. and are commonly grounded on both sides of the electrode section,
An ion-selective electrode device characterized in that a metal body is arranged so that a hole formed in the center faces the flow path. (2) The ion-selective electrode device according to claim 1, wherein the metal body is made of a material selected from the group consisting of gold, platinum, silver, stainless steel, and carbon.