JPS62180260A - Magnesium ion sensor - Google Patents

Abstract

PURPOSE:To improve ion selectivity and to make responsiveness faster by providing a film having a reversible oxidation reduction function on the surface of a conductive base body and providing a magnesium ion selective film thereof thereby constituting a sensor. CONSTITUTION:A carbon material, gold, etc., are used as the conductive base body and the film (oxidation reduction film) having the reversible oxidation reduction function is formed on the surface thereof. An org. compd. of quinone- hydroquinone type or amine-quinoid type or high-polymer compd. is used as the oxidation reduction film. The magnesium ion selective film is provided on said film to constitute the sensor. A film formed by depositing the magnesium ion carrier, for example, N,N'-diheptyl-N,N'-dimethyl-1,4-butanediamide, etc. on the high-polymer film is used as the magnesium ion selective film. Since the magnesium ion selective film is provided via the oxidation reduction film, the need for an internal liquid of the sensor is eliminated and the miniaturization is made possible. The potential responsiveness is thus improved and the high- accuracy is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnesium ion sensor for red sea bream, zebrafish, semen, and more specifically, a solid state in which the internal solution is not completely absorbed. Prior Art and No. 7 Problems] Conventionally, an ion-selective electrode has been used as a sensor for measuring the concentration of magnetocium ions in a solution based on electrode potential response. The ion-selective electrode is based on the internal structure of the electrode.
(1) One with a built-in ion-selective membrane, an internal (standard) solution, and an internal reference electrode immersed in the solution (barrel-type liquid membrane type), and (2) an ion-selective membrane directly attached to a conductive substrate. It can be roughly divided into those with a g-structure (film-coated type).

Wilhelm Simon et al. (1)
reported on a friend magnesium ion sensor using a barrel-type liquid membrane type membrane containing a carrier compound that is selective for magnesium ions as a magnesium ion-selective membrane [Analytical Chemistry (
Analytical Chemistry) 1 unit,
2400-2402 (1980); Helvetica Fist Himika Acta (He1v, Chim, Acta) 63
.

2271-2279 (1980)).

However, the *pole of the barrel-type liquid film drop in (1) is
Since it has an internal liquid and an internal liquid chamber, it has the disadvantage that small-sized batteries are generally in poor demand.On the other hand, the electrical repair of membrane-coated batteries in 12), which is thought to be possible to downsize, is based on magnesium. Not known as far as ionosensors are concerned.

[Means for solving problems]

As a result of extensive research into solid-state magnesium ionosensors that do not have an internal liquid or an internal liquid chamber, the inventors have developed a magnesium ion selective membrane 't 24ttf.

The electrode of type 12), which is directly deposited on the surface of a chemical substrate, requires a thicker film to obtain the ion selectivity required in practice, and has a slow response speed. It is clear that it is not satisfactory in terms of being easily affected by dissolved oxygen in the solution, etc. However, it is possible to reduce the size by coating it with a film that has a redox function, and the above problems such as ① and ② A magnesium sensor with excellent sensor characteristics without defects was completed.

That is, the present invention includes a magnesium ion sensitive part,
This is a magnesium ion sensor that measures the concentration of magnesium ion in a solution by electrode potential response. Magnesium ion/cer/cer is characterized by having a magnesium ion-selective pattern coated on the entire surface and beyond the surface.

The magnesium ion selective membrane is a polymer membrane on which magnesium ion/ΦYarya substance gold is supported.

Examples of the conductive substrate used in the magnesium sensor of the present invention include 2, for example, basal plane pyro
Conductive carbon materials such as lytic graphite (hereinafter referred to as BPG), glassy carbon; gold, platinum.

Examples include metals such as copper, silver, and palladium, particularly noble metals, or metals whose surfaces are coated with half-metals such as 1/dium oxide and tin oxide. For practical use, conductive carbon materials are preferable.
Particularly preferred is BPG.

Friend, the town is full of reverse redox abilities (below).

An oxidation-reduction film) is an electrode formed by adhering this film to the surface of a conductive substrate, and can generate a constant potential on the conductive substrate through a reversible oxidation-reduction reaction.

In the present invention, it is particularly preferable that the potential does not vary depending on the oxygen gas partial pressure. As such an acid 1 arsenic reduction film, 1
For example, momme 1. ) an organic compound film or a polymer film capable of performing a quino/-human quinone type redox reaction;
(2) Suitable examples include organic compound membranes or polymer membranes capable of carrying out amino-quinoid type redox reactions. In addition, here, the redox reaction of Kino/-human aQ/ type is TJ (in the case of coalescence, if taken in the upper row, 1
For example, it refers to the reaction represented by the following reaction formula.

Q 0) I (In the formula, R' and R' represent, for example, a compound having an aromatic structure.) '1 What is an ami/-quinoid type redox reaction?

Similarly to the above, if we consider the case of polymers, 4 refers to those expressed by the following reaction formula, for example.

(In the formula, m3.tt' indicates a compound with an aromatic-containing structure.) As a compound that can form a film having such a reversible redox function, Ri11e is the following (al~(C1 The following compounds are mentioned.

(In the formula, Ar, #:l: aromatic nucleus, each R5 is a substituent, m
■Effective valence number of y ri l or Ar, nl is mouth or Ar.

The aromatic nucleus of the hydroxy7 aromatic compound Ar, represented by /nuclei, biV nucleus, chrysene, maki, perylene nucleus, ko ``gofu/even if it is a polycyclic nucleus such as a nucleus, it is not only a bone nucleus, but also a bone nucleus *
;It may be in the gi bone 1. Examples of the substituent 5 include alkyl groups such as methyl groups, aryl groups such as phenyl groups, and rogen atoms. in particular.

Dimethylphenol, phenol, hydroquine pyridine, 0- or m-benzyl alcohol, o
-, m-mayu is p-hydroxy7be/zaldehyde, 0-
or m-hydroquine acetophenol/, 〇-1m- or p-human acetophenol/p-abiophenoy, o-lm-mayu p-pe/dylphenol, o+, m- or p-
Human akinbe/zopheno/, 0-1m-t or p-carboquinphenol, diphenylphenol.

2-Methyl-8-hydroxyquinolino, 5-hydroxy-1,4-naphthoquino7.4-Cp-hydroxyphenyl)2-butanoy,t,5-dihydroquine-1,2,
3,4-tetrahydronaphthalene bisphenol A,
Examples include salicylanilide, 5-human axy7a/, 8-hydroquinynoy, 1,8-dihydro ay7a/traquinone, 5-human axy-1,4-naphthoquino/, and the like.

tb+ The following formula (in the formula, Ar is an aromatic nucleus, each R6 is !9 groups, 0m3 is 1
or the effective valence number of Arl, ns is O or Ar.

As the aromatic nucleus and substituent R6 of the amine aromatic compound Arl (representing the effective valence number -1), the same ones as Ar+ in the compound (al) and the tit substituent a11 are used, respectively. Specific PI of the compound t-To name, anilyy, t+2-diaminobe/ase/, aminobire/
, diaminobile/, aminochrysene.

Diaminochrysene, l-aminozene, v:y.

9-7 minophenanthrey, 9.10-diaminofena/tre/, l-aminoa/traquinone.

p-phenoxyanili/, O-phenyl/diami7. p
-Chloa aniri y, 3.5-dichloro a aniri 7, 2
．． 4 + 6-driculo aanili/.

N-methylanii I)y, N-phenyl-p-phenylenediami/etc.

(cll, 6-pyre/quinoy, t, 2.5+8-tetrahydroquinalizari/, phenanthrenequinone, 1-aminoanthraquino/, purpurin.

l-amino-4-hydroxyanthraquinone.

Kino 7 such as antralphine.

Among these compounds, especially 2,6-xylenol, l
-Aminopyrene is preferred.

One example of a compound capable of forming redox I1g according to the present invention is as follows.

(dl Bo13 (N-Methyl Aeri/) [Inunuki, Suida.

Koyama, Journal of the Chemical Society of Japan, 1801-1809 (1984
) ).

Poly(2,6-dimethyl-1,4-phenylene/ether), poly(0-phenylenediamide/).

Contains compounds of (a) to (C1) such as poly(phenol), polyxylenol; quino/vinyl polymer condensation compounds such as pyrazoloquino/vinyl monomer polymers and inaloxazino vinyl heptapolymers; v Iso compound, a low polymerization degree polymer compound (oligomer) of the compounds (a) to tc).

Examples of roui include those having the redox reactivity such as tal~(C1?) fixed to polymeric compounds such as polyvinyl compounds and polyamide compounds.In this specification, the term monopolymer refers to homopolymer. It includes both polymers and interpolymers such as copolymers.

In the present invention, in order to apply a compound capable of forming a redox film on paper to the surface of a conductive substrate.

Amino aromatic compounds, aromatic compounds, etc. can be synthesized in advance by directly polymerizing them on the substrate surface by electrolytic deposition, or by applying electron beam irradiation, light, heat, etc. A method of dissolving a polymer film in a solvent and fixing the solution to the substrate surface by dipping, coating, and drying, and a method of fixing the polymer film directly to the substrate surface by chemical treatment, physical treatment, or irradiation treatment. You can take it. Among these methods, the deoxidative polymerization method is particularly preferred for 1.

In the present invention,! The deoxidative polymerization method is carried out by electrolytically oxidizing and polymerizing amino aromatic compounds, hydroquine aromatic compounds, etc. in a solvent in the presence of excessive support [solites] to deposit a polymer film on the surface of a conductor. Ru. Examples of solvents include acetonitrile.

water, dimethylformamide, dimethyl sulfoxide, probilene/carbonate, etc., and as a supporting electrolyte,
For example, sodium perchlorate, sulfuric acid.

Suitable examples include disodium sulfate, sulfuric acid, boric acid, potassium tetrafluorophosphate, and quaternary ammonium salts. The polymer films thus deposited are generally very dense and even thin films can block oxygen permeation. However.

In order to achieve the effects of the present invention, the redox film is not particularly limited as long as it has the redox reactivity tV, and it does not matter how dense the film is.

The thickness of the redox film is 0. It is preferable to set L pfn-0.5 mm. If it is thinner than 0.1 pffl, the effect of the present invention will not be sufficiently achieved, and if it is thicker, the membrane resistance will be high, which is not preferable.

91. The redox membrane used in the present invention can be used by impregnating it with an electrolyte. As an electrolyte, 1
Examples include phosphoric acid, dipotassium hydrogen oxide, sodium perchlorate, sulfuric acid, tetrafluoroborate, tetraphenylborate, and the like. A simple method for impregnating the redox membrane with an electrolyte is to attach the redox membrane to a conductive substrate and then immerse it in an electrolyte solution.

The magnesium ion/selective membrane that is deposited over the surface of the redox membrane deposited on the conductive substrate as on paper may be one in which, for example, a magnesium ion carrier substance and an electrolyte salt are supported on a polymer compound. A membrane is used.

As a magnesium ion carrier substance.

There is no particular restriction as long as it is a substance that can selectively transport magnesium ions.1 For example, N, N'-diheptyl-N, N'-dimethyl-1,4-buta/diamide expressed by the following formula %, the following formula % N,N'-diheptyl-N,N'-dimethylmalonamide expressed by the following formula%, 2-ethyl-N,N'-dihephthyl-N,N'-dimethylmanamide expressed by the following formula% (In the formula, ul and R8 each represent I, C1, F or Br f) A compound represented by: 1,3-diphenyl-1,
Examples thereof include 3-1a/diol, l-phenyl-3-(p-chlorophenyl)-1,3-p-a/diol, and the like.

Friend, polymer compounds include 1, such as vinyl chloride resin,
Examples include vinyl chloride-ethylene copolymer, polyester, polyacrylamide, polyurethane, silicone resin, etc., and those that do not easily release plasticizers are used. Examples of such plasticizers include dioctyl sebacate, dioctyl adibate, dioctyl maleate, di-n-octylphenylphosphonate, and the like. (9) Tetrahydrofurano is preferably used as the solvent.

To deposit a magnesium ion-selective membrane on the surface of a redox membrane, for example, 50 to 500 parts by weight of a plasticizer and 71 parts of magnesium ion are added to too many parts of a polymer compound as a carrier. Dissolve 50 parts of the liquid material ffO,ln and electrolyte salt etc. in a solvent (e.g. tetrahydrofurano) and add the base electrode (here, the redox film coated electrode) to the fcfIi solution, immerse it, pull it up, and air dry it. Repeat drying to obtain a carrier film thickness of 50μfrL~3! ll! , e#
It is preferable to use Q, 3 y + m ~ 2 to do some work. Alternatively, paste vinyl chloride, magnesium ion carrier material, plasticizer, and electrolyte salt are mixed in the above weight ratio, and then placed on the substrate to a thickness of 50 μm to 3.1 m.

A magnesium 7 ion carrier film can also be obtained by heat treatment at 160° C. for 1 minute to form a gel.

〔Effect of the invention〕

Since the present invention is a magnesium ion/sensor composed of two layers in which a magnesium ion selective membrane is coated on the surface of a redox membrane as seen above, (1) the conventional barrel liquid-viewing membrane type electrode Compared to a type of magnesium ionosessor, the oxidation-reduction membrane transforms the internal liquid and moves the base electrode, so it does not require all the internal liquid, making it more compact and safe with no liquid leakage or damage. As a result, the responsiveness of the first layer is stable at the x < aim level, and the magnesium ion density can be measured with precision.

(11) Also, compared to a coated wire type magnesium ion sensor in which an ion-selective membrane is directly attached, the r
6 remain! Magnesium ion selectivity is high due to the influence of various coexisting substances including diatomic elements.

It can be used regardless of the type of test liquid.

It has a fast response time and excellent stability.

(+lil Since the structure of the 1Fi electrode is simple, it can be manufactured in large quantities.

It has various features such as 1.

[Implementation row]

Next, Examples and Test N'x will be described.

Implementation Example 1 A magnesium sensor shown in FIG. 1 was fabricated using the following method.

Play during Basal/・Pilority 7ku・Craphite (
B PG, Union Carbide) plate, diameter 1
．． Cut out the cylindrical BPGIIt of l i"Im, and then attach the lead clothing 12 (Teff a/coated copper wire) to the bottom surface 11 using a K4'tW adhesive (manufactured by Amico, C-850-6) 18. Connect this f'L with Tef A/chave (inner diameter 1.7 m x outer diameter 2.1 II) l 3 and heat shrink tube (alpha wire ill! 14 cylindrical BPG II will come out 1.5 g) The surrounding area was coated and insulated as shown in the figure.Furthermore, the tip of the BPG II taken out *ILb was shaved into a hemispherical shape, and the hemispherical surface of the seventh part and the side of the BPG cylinder were sanded with sandpaper 1 (8
2000).

In this way, fabricate fcBPG' as the working electrode.

A three-electrode cell was constructed using a saturated sodium chloride calomel electrode (SSCE) t-reference electrode and a platinum cell as a counter electrode, and an electrolytic oxidation polymerization reaction was carried out under the following conditions.

(@Solution) 0.5M2.6-KinleTool 0.2IvI Sodium perchlorate solvent Ni-heptonitrile (Tff, Pingtung case) Action '1-ward pot potential'? 1 from υV for S SCE,
After s v to 3 regression side (5f) mV/sec>I,, fC.

Potential electrolysis was performed for 10 minutes at 1,5 V vs. 5 SCE.

In this manner, the exposed surface of BPG II was coated with 2° 6-K/Lenol zero polymer g15 to a thickness of about 30 μfn. This membrane electrode was washed with acetonitrile solvent to remove unreacted 2,6-k/1/nol, washed with water, dried, and then coated with 16 tons of magnesium 7-ium ion carrier membrane in 6 prefectures.
I'm sorry for the coating.

The magnesium ion carrier film 113 was formed by repeating dipping and drying three times using a constant speed elevator. The film thickness is 0.3 ml at the tip of the electrode flb, 4
11 side 8 (SL lc to form a 0.5II 1 ml film (Immersion liquid composition)
Luka Company's Jiri Tetrakis (p-chlorophenylene) dissolved potassium 1mseban/dioctyl acid 647 ~ Tetrahydra
4 ml of flannel, prepared in this way,
After cutting the magneto/sensor thoroughly,
LmM 4 (IZ-” nesium (MgClz
・After immersion in the 6H10) bath for about 12 hours, the first experiment vc)TJ was carried out.

Test row 1 The magnesium ion sensor of the present invention prepared in Example 1 and the 5SCE as an a-lighting electrode were immersed in a 1mM magnesium chloride solution, and added to 1M magnesium chloride/lamb as a solution to remove magnesium ions. The electromotive force was measured at a total temperature of 36.8° C. while increasing the temperature by 7°C. of measurement,
The fruit is shown in Figure 2.

枳11 tt p 4. The relationship between Hα force and magnenium io//I & degree shows a linear relationship in the range of 10-3 to 10-''M, and the spray is 29°8 m ¥/k
g (Mg”1).

A response according to the Ncrnst equation was obtained.

Next, the influence of selectivity with cations was studied. The value taken as the common logarithm of the selection coefficient is log
) (Mu01 score = -1,12, for sodium ions log K; S'', N, = -0,92, for calcium ions logi crystal', ', C, = 1.
6 in 44. Therefore.

It can be seen that the processor of the present invention has a selectivity of about 10 times for potassium ions and sodium ions, but a selectivity of about 1/25 for calcium ions.

In addition, the measurement was performed at the concentration of interfering ions/(positive 1 ion) of 0 and 1.
This was done by keeping M to IM constant and changing the magnesium ion once.

Also, the response speed was fast, with a 95% response rarely occurring within 1 minute.

As a result of investigating the shadow @ for dissolved oxygen at 4 degrees, the electromotive force when O2 and teeth are separately shaken for 3 hours is ±2m.
An enlarged cross-sectional explanatory diagram of the next 0 is shown, which shows that it is not affected by the filler O7 within V. Figure 2 shows the relationship between the electromotive force and magnesium io/@ degree of the present invention processor produced in Example 1? The drawing shown is correct.

11... BPG lla... Bottom ttb...
・Tip fiLLc...Side part 12...Lead wire
13...Tef a/tube 14...Heat shrink tube 15...Redox membrane 16...Magnesium ion/Carry f-membrane 17...
Insulator 18... Conductive adhesive 19... Magnesium ion/sensing part 19... Magnesium ion

Claims (1)

[Claims] 1. A magnesium ion sensor that includes a magnesium ion sensitive part and measures the magnesium ion concentration in a solution by electrode potential response, the magnesium ion sensitive part having a surface of a conductive substrate that is reversibly oxidized. A magnesium ion sensor comprising a coating having a reducing function, and further comprising a magnesium ion selective membrane on the entire surface of the coating and over the coating. 2. The magnesium ion sensor according to claim 1, wherein the magnesium ion selective membrane is a polymer membrane supporting a magnesium ion carrier substance.