JPH06201639A - Ion-selective electrode using photoresponsive calixarene derivative - Google Patents

Abstract

PURPOSE:To perform a plurality of ion analyses with a single electrode by using a filmlike matter obtained by dispersing calix [4] arene derivative in polymer containing plasticizer as neutral carrier as an operating electrode. CONSTITUTION:Calix [4] arene derivative is one type of twoanthracene group- containing compound in which 25-position and 27-position or 26-position and 28-position of a molecule are substituted with 9-anthryloxy-ethyl group, and represented by a formula A. In the formula, X is particularly preferably CH2CH2 CH3, Y1, Y2 are generally the same, and preferably -H, -C(CH3)3. When the compound of the formula A is applied to the operating electrode by forming to a film state with plasticizer-containing polymer, selectivity to Nak is enhanced if it is irradiated with visible light (350nm or more), and Na<+> exhibits different ion selectivity when it is irradiated with an ultraviolet light (280nm or less0. For example, in order to obtain Li<+> selectivity, plasticizer of phosphoric acid series such as TOP is used. As the polymer, PVC is particularly preferable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion-selective electrode, and more particularly, to a novel ion-selective electrode which exhibits selectivity for a plurality of ions in response to light.

[0002]

2. Description of the Related Art Ion-selective electrodes are used for H ⁺ , Na ⁺ , K ⁺ , Ca ²⁺ , Mg ^{2+ in} the field of clinical examination.
It is widely used as a means for measuring the concentration of ions such as. In addition, the ion-selective electrode can be used to analyze a specific ion in various industrial fields such as environment, food, medicine, and biotechnology.

The ion-selective electrode utilizes the fact that the substance used for the working electrode (called a neutral carrier) selectively reacts with a specific single ion. For example, the Na ⁺ selective electrode is an electrode for selectively measuring only sodium ions, and the same is true for the so-called K ⁺ selective electrode and Cs ⁺ selective electrode. That is, the conventional ion-selective electrode is intended to analyze only one specific type of ion in a sample liquid in which several ions are mixed,
It was not possible to analyze heterogeneous ions with a single electrode. Thus, for example, sodium ions (Na
⁺ ) And cesium ion (Cs ⁺ ) are to be measured,
At least two ion-selective electrodes, namely Na ⁺
Selective and Cs ⁺ selective electrodes were required. If an attempt is made to analyze a plurality of ions with a single device, the configurations of the electrode section and the detection section will be large and large, which is naturally not preferable in terms of cost.

[0004]

The inventors of the present invention have conducted extensive research on the neutral carrier of an ion-selective electrode, and reversibly change the structure in response to light. We have found different substances, and by utilizing them, we have completed an ion-selective electrode that can analyze multiple different ions with a single electrode.

Thus, the present invention provides for the 25-position and the 27-position.
A plasticizer having no absorption spectrum that overlaps with anthracene, using a calix [4] arene derivative substituted at the 9-anthryloxy-ethyl group at the -position or at the 26-position and the 28-position as a neutral carrier. There is provided an ion-selective electrode, characterized in that a film-like material obtained by dispersing it in a polymer containing is used as a working electrode.

The calixarene, which is a raw material of the neutral carrier substance used in the present invention, is a cyclic oligomer in which a plurality of phenol units are bonded by a methylene group, and exhibits unique properties as an atom or molecule recognition element. In recent years, it has been studied as a new host compound in host / guest chemistry. The present inventor has focused on the recognition function of calixarene for a metal atom, and synthesized various kinds of calixarene derivatives to carry out research. As a result, two anthracene groups (bianthracene)
It has been found that the above-mentioned calixarene derivative having a bonded group has different ionic species that are selectively recognized by irradiation with light.

The calixarene derivative used in the present invention is a calixarene having four phenol units, that is, two calix [4] arene molecules.
5-position and 27-position (or 26-position and 28-position
Position is a 9-anthryloxy-ethyl group (9-anthrylo
xy-ethyl) -substituted bianthracene-containing compound, which can be represented by the following formula [Formula 1].

[0008]

[Chemical 1]

As the X and Y (Y ₁ , Y ₂ ) in the calixarene derivative represented by the above-mentioned formula [Chemical Formula 1], various kinds of calixarene derivatives which have been conventionally used in the calixarene derivative can be used unless the object of the present invention is impaired. Can be atomic groups or functional groups of X is preferably a group such that the entire calix [4] arene molecule is likely to have a cone structure as a conformation. Examples of preferred _{X, -C n H 2n + 1} [n is an integer of 2 or more, preferably 2-5 _{integer], - (CH 2 CH 2} O) m
CH ₂ CH ₃ [m is an integer of 1 or more, preferably 1 to
4 is an integer of 4], or —CH ₂ CO ₂ CH ₂ CH ₃ . A particularly preferred example of X is CH ₂ CH ₂ OCH.
₂ CH ₃ . Y ₁ and Y ₂ are generally the same,
It may be different. Y ₁ and Y ₂ are considered to be related to the affinity with the plasticizer. Preferred examples of Y ₁ or Y ₂ are —H, —C (CH ₃ ) ₃ [t-butyl group], or —C (CH ₃ ) ₂ C (CH ₃ ) ₃ [t-octyl group].

It has been conventionally known that a compound having two anthracene groups causes a photodimerization reaction, but no system has been found that combines this reaction with the selectivity for a specific ion at the electrode. In the present invention, the calixarene derivative represented by the above [Chemical formula 1] is applied to an ion-selective electrode after film-forming it with a plasticizer-containing polymer. It is based on the finding of a system in which the value changes, and this system can be shown as in FIG.

That is, the 25-position and the 27-position (or the 26-position and the 28-position) are 9-anthryloxy-.
A film containing a calixarene derivative substituted with an ethyl group has a significantly higher selectivity for sodium ions when irradiated with light having a wavelength of 350 nm or longer (visible light), which is caused by the photodimerization reaction. B in Figure 1
In this state, it is considered that the cavity is extremely suitable for reacting (complexing) with Na ⁺ . Surprisingly, when the system according to the present invention is left in the dark after irradiation with visible light or irradiated with light having a wavelength of 280 nm or less (ultraviolet light), it is different from sodium ions. It shows remarkable selectivity. It is understood that this is because the ion selectivity of the plasticizer itself is exerted in the system containing the calixarene derivative which is not photodimerized (in the state of FIG. 1A). However, as the plasticizer, a plasticizer having no absorption band overlapping the absorption spectrum of anthracene is used.

The types of ions for which the electrode composed of the non-photodimerized calixarene derivative exerts selectivity are
It depends on the plasticizer used. For example, in order to obtain lithium selectivity, a phosphoric acid-based plasticizer such as tris (2-ethylhexyl) phosphate (TOP), dioctylphenylphosphate (DOPP), tricresylphosphate (TCP) is used. Further, in order to obtain cesium selectivity, an aromatic or fatty acid-based plasticizer having no overlapping absorption with anthracene, such as di (2-ethylhexyl) sebacate (DOP) or di (ethylhexyl) adipate (DOA). To use.

As the polymer for preparing the membrane material used in the present invention, various materials used for the membrane for the working electrode of the ion selective electrode can be used, but polyvinyl chloride is preferable. And polyvinylidene chloride, with polyvinyl chloride (PVC) being particularly preferred.

Thus, as a preferred specific example of the ion-selective electrode according to the present invention, Y ₁ and Y ₂ of the formula ₁ are t-.
A calix [4] arene derivative represented by the following formula [Chemical Formula 2], which is a butyl group, is used as a neutral carrier and a membrane dispersed in PVC containing a plasticizer TOP [n-trioctyl phosphate] is used ^. -Li ⁺ -selective electrode and Na ⁺ -C using a film obtained by dispersing in PVC containing plasticizer DOP [n-dioctyl phthalate] or DOS [di (2-ethylhexyl) sebacate]
There is an s ⁺ selective electrode.

[0015]

[Chemical 2]

The anthracene group-containing calixarene derivative used in the present invention can be prepared according to the synthetic route shown in FIG. The preparation method in each step is roughly as follows.

I) Preparation of compound (1) [9- (2-bromoethoxy) anthracene]: Anthracene, sodium hydroxide and 18-crown-6 are dissolved in 1,2-dibromoether and water and the mixture is mixed at 25 ° C. for 3 days. After stirring for a day, the organic layer is separated and the solvent is removed. Chloroform /
Recrystallization in hexane gives compound (1).

Ii) Preparation of compound (2): Tetrahydroxycalix [4] arene derivative as a starting material
Bromo reagent (BrX) and potassium carbonate are added in acetone and reacted for 1-4 days at 75 ° C. After removing the solvent, the solid is washed with dilute hydrochloric acid and water. Recrystallization in chloroform / hexane gives compound (2).

Iii) Preparation of compound (3): Compound (1)
And (2) together with NaH in THF
The reaction is carried out at ℃ for 1 to 3 days under a nitrogen atmosphere. After cooling the mixture, methanol is added to quench the NaH and the solvent is removed. The compound (3) is obtained by purifying the obtained solid content using a silica gel column.

In accordance with the present invention, a calixarene derivative obtained as described above, together with a polymer such as PVC and a plasticizer (usually , A lipophilic additive is often added in order to increase the sensitivity), and the solvent may be removed after being uniformly dissolved in a suitable solvent. At this time, about 1.50 of the calixarene derivative was added to the entire system consisting of the calixarene derivative / PVC / plasticizer.
It is preferable that the compounding amount be about 8.0% by weight. Further, the plasticizer is 20.0 to (plasticizer + PVC).
It is preferably used at 50.0% by weight, especially about 30% by weight.

The membrane thus obtained is used to prepare the working electrode of the ion-selective electrode according to methods known in the art. 3 and 4 schematically show the structure of a typical ion selective electrode.

As shown in FIG. 3, in order to measure the potential using the ion selective electrode, the working electrode 2 and the standard electrode 3 are connected to the electrometer 1. As will be described later, a film-like material containing the calixarene derivative according to the present invention is used for the working electrode 2. The sample solution 5 to be measured is
Stir with a magnetic stirrer and add salt bridge 4 (0.1
Molybdenum acetate) is immersed. The other end of the salt bridge 4 is dipped in a saturated potassium chloride aqueous solution 6 and the silver / silver chloride standard electrode 3 is put therein.

FIG. 4 shows the working electrode 2 in more detail. A silver wire 11 functioning as a silver / silver chloride internal standard electrode is inserted into an electrode holder 12 (for example, made of acrylic resin or PVC), and an internal standard solution 13 (10
^-3 molar sodium chloride solution). A film 14 containing the photoresponsive calixarene derivative according to the present invention is attached to one end of this holder. Therefore, the overall configuration of the device described above as an electrochemical cell can be expressed as: Ag / AgCl | a
q. NaCl (1 × 10 ⁻³ mol dm ⁻³ ) | Photoresponsive film-like material | Sample solution | aq. Lithium acetate (1 x 10 ^-1 mol d
m ^-3 ) | KCl (saturated) | Ag / AgCl.

The ion-selective electrode according to the present invention can change the kind of ions to be selectively measured by irradiation with light. For this purpose, as shown in A of FIG. 4, light (indicated by L in the drawing) is emitted from the outside of the electrode. Alternatively, as another aspect, as shown in FIG. 4B, light (L) is transmitted through an optical fiber (optical fiber) 15.
May be irradiated from inside the electrode.

When the measurement is performed using the apparatus as described above, the selection between specific ions is calculated by calculating the selection coefficient from the measurement data according to the Nicolsky-Eisenman equation, as is well known in the art. Sex can be evaluated. The details are described in an appropriate reference book or document, and therefore omitted here, but generally the following is performed. That is,
A reference ion (eg, N
a ⁺ ) and a constant concentration of interfering ions (M) (for example,
1 × 10 ^-4 mol dm ^-3 ) and constant temperature (eg 25
The measured potential at ° C.), respectively, when a E _S and E _M, if not divided by the theoretical slope value calculated the E _M -E _S from the Nernst equation in the temperature, the selectivity coefficient (log K
_N a, _M ) is obtained. A smaller value indicates that the reference ion has higher selectivity for interfering ions.

The electrode using the photoresponsive calixarene derivative according to the present invention has a unique property of functioning as a selective electrode for two different target ions, and in any case of measuring any ion, ion selection is performed. It possesses the performance that has been conventionally required as a conductive electrode. For example, the response speed of the electrode is sufficiently high to reach a steady state within only 5 to 10 seconds. Also,
A response is obtained that meets or approximates the Nernst equation over the concentration range of 1 × 10 ⁻¹ to 1 × 10 ⁻⁴ mol dm ⁻³ . The value of the Nernst slope is in the range of 50-62 mv / decade.

The present invention will be described below with reference to examples in order to further clarify the characteristics of the present invention.

[0028]

EXAMPLES Example 1: Preparation of calixarene derivative 9- (2-Bromoethoxy) anthracene: 1 containing anthrone (25.0 g), dicyclohexano-18-crown-6 (0.70 g) , 2-dibromoethane solution (300 ml) and sodium hydroxide (2
5.0 g) aqueous solution was stirred at room temperature under nitrogen atmosphere for 3 days. The organic layer was separated and 1N HCl (50 ml x
3) and washed with water (50 ml x 4), then anhydrous MgSO
Dried at ₄ . After removing the solvent under reduced pressure, the obtained yellow solid substance was recrystallized in a mixed solvent of hexane / chloroform to obtain 9- (2-bromoethoxy) anthracene yellow crystals. 28.6 g (yield 73.8%); melting point 126.
~ 127 ° C; mass spectrum (EI) m / e301 (M
⁺ ); Elemental analysis value C63.97, H4.39 (calculated value C
63.81, H4.35).

5,11,17,23-tetra-t-butyl
Le-25,27-dihydroxy-26,28-bis
Of (2-ethoxyethoxy) calix [4] arene
Preparation: 5 , 11, 17, 23 shown previously as [Chemical Formula 2]
-Tetra-t-butyl-25,26,27,28-tetrahydroxycalix [4] arene (25.0
g), K ₂ CO ₃ (32.0 g), and 2-bromoethyl-ethyl ether (50.0 g) were dissolved in 300 ml of acetone, and the resulting solution was heated and reacted at a reflux temperature in a nitrogen atmosphere for 4 days. After removing the solvent under reduced pressure, the residue was extracted with chloroform (50 ml × 3). The obtained chloroform solution was washed with 1N HCl (50 ml × 3) and water (50 ml × 4) and then dried over anhydrous MgSO ₄ . The solvent was removed under reduced pressure, and the obtained white solid content was recrystallized in hexane / chloroform to obtain the desired compound represented by the following [Chemical Formula 3]. 15.61 g (yield 58.
4%); melting point 167-168 ° C; mass spectrum (E
I) m / e 792 (M ⁺ ); Elemental analysis C78.54, H
9.16 (calculated value C78.74, H9.15).

[0030]

[Chemical 3]

5,11,17,23-tetra-t-butyl
Ru-25,27-bis (2-ethoxyethoxy) -2
6,28- [2- (9-anthryloxy) ethoxy]
Preparation of calix [4] arene: 9- (2-bromoethoxy) anthracene (1 obtained as above.
0.0 g), a compound (1.00 g) represented by [Chemical Formula 3] and NaH (1.0 g) dissolved in 50 ml of THF, and the obtained solution was refluxed at a reflux temperature for 5 days under a nitrogen atmosphere. After heating and reacting, it was cooled to room temperature. Methanol was added to quench the residual NaH. After removing the solvent by evaporation, the residue was dissolved in 300 ml of chloroform, washed with 1N HCl (50 ml × 3) and water (50 ml × 4), and dried over anhydrous MgSO ₄ . The yellow solid content obtained by removing the solvent under reduced pressure was separated by chromatography using a silica gel column (effluent hexane / chloroform 3: 1 mixed solvent) to obtain the desired calix [4] arene derivative represented by the following [Chemical Formula 4]. Got 0.34 g (yield 21.8%); melting point 177-
178 ° C, mass spectrum (SIMS) m / e1233
(M ⁺ ), 1256 ([M + Na] ⁺ ); Elemental analysis C8
1.91, H7.95 (calculated value C81.78, H7.8
4).

[0032]

[Chemical 4]

Example 2 Preparation of Membrane 50 mg PVC (molecular weight n = 1100), TOP [tris (2-ethylexyl) phosphate] as a plasticizer
100 mg, lipophilic additive KTpClPB (potassium tetra-bis-p-chlorophenylboronic acid) 1 mg, and 5 mg of the calixarene derivative of the formula [Chemical Formula 4] prepared in Example 1 were dissolved in 1,2-dichloroethane 3 ml. The obtained solution was poured into a Petri dish (diameter 3.0 cm), and the solvent was evaporated at room temperature for 3 days in the dark under a nitrogen atmosphere. As a result, a transparent and elastic film (thickness: about 0.15 mm) was formed. Was obtained.

Example 3 Preparation of Electrode and Measurement of Membrane Potential The film-like material prepared in Example 2 was cut into a disk shape having a diameter of 8 mm, and as shown in FIG. 4A, a PVC electrode holder (outer diameter 8 mm) was used. , An inner diameter of 4 mm and a height of 7 mm), and the ion selective electrode device as described above with reference to FIG.

Potential measurements were made on an aqueous solution obtained by dissolving analytical reagent grade chlorides (LiCl, NaCl, CsCl, RbCl, etc.) in deionized water. Using a high-pressure mercury lamp with a filter, light irradiation (365 nm) was performed as described above with reference to FIG. 4A, and the potential before and after irradiation was measured. The irradiation time is 15 minutes unless otherwise specified. 1 × 10 ^-1 mol / dm ³ to 1 ×
Potential measurements were performed on six kinds of concentrations of metal chloride aqueous solutions in the range of 10 ⁻⁶ mol / dm to determine the selectivity coefficient (log K _Na , _M ).

The order of selection coefficient in the dark before light irradiation is Li ⁺ (1.82)> NH ₄ ⁺ (0.83)> Na
⁺ (0.00)> K ⁺ (-0.32)> Rb ⁺ (-0.5
3)> Cs ⁺ (-0.59), and this electrode has a high L
It was found to have i ⁺ selectivity.

However, after irradiation with 365 nm for 15 minutes, the selection coefficient was Na ⁺ (0.00)> K ⁺ (-3.
06)> Li ⁺ (−4.02) = NH ₄ ⁺ (−4.02)
> Rb ⁺ (-4.73)> Cs ⁺ (-5.20),
Exhibits excellent Na ⁺ selectivity.

Such reversal of ion selectivity can be understood from the value of electric potential. That is, the concentration of the chloride aqueous solution is 1
Measurement potential difference (E _Li ⁺ −E _Na ⁺ ) at × 10 ⁻¹ mol / dm ³
Was 107 mV before light irradiation, while it was -237 mV after irradiation. As described above, when a film-like material obtained by dispersing a calixarene derivative having a bianthracene group represented by the above [Chemical Formula 4] in PVC containing plasticizer TOP is used as a working electrode, Correspondingly, both Li ⁺ and Na ⁺ selectivity are obtained.

FIG. 5 shows the results of a cycle test in which the above irradiation and non-irradiation of light are repeated. That is, after the Na ⁺ selectivity and potential measured after the light irradiation was observed, was repeated to potential measurement was left 24 hours in the dark, as shown in FIG. 5, Li ⁺ selectivity / It was confirmed that the Na ⁺ selectivity conversion is reversible.

Example 4 The calixarene derivative prepared in Example 1, DOP (n-dioctyl phthalate) as a plasticizer, and P
A membranous material was prepared from VC in the same manner as in Example 2, and the potential was measured in the same manner as in Example 5.

The order of the selectivity coefficient in the dark before irradiation is Cs ⁺ (1.78)> Rb ⁺ (1.45)> K.
⁺ (1.34)> NH ₄ ⁺ (0.73)> Li ⁺ (0.0
7)> Na ⁺ (0.00), which was found to have Cs ⁺ selectivity. The selectivity coefficient after irradiation with 365 nm is N
a ⁺ (0.00)> K ⁺ (-1.61)> Pb ⁺ (-2.
56)> Cs ⁺ (−3.56)> NH ₄ ⁺ (−6.54)
> Li ⁺ (−6.58), showing excellent Na ⁺ selectivity. Since the difference between the potential with respect to Cs ⁺ and the potential with respect to Na ⁺ changed from 175 mV before irradiation to -210 mV after irradiation, C before and after irradiation with light
It can be seen that the s ⁺ selectivity is converted to Na ⁺ selectivity. Thus, when DOP is used as the plasticizer, Cs ⁺
A / Na ⁺ selective electrode is obtained.

When the measurement was performed while changing the irradiation time, the selectivity coefficient (log K _{Na, M} ) was 2 minutes (1.1
5) 5 minutes (-2.87) 15 minutes (-3.56), 25
Min (-3.57), 30 min (-3.46), and the photodimerization of the calixarene derivative in the film was 1
It is estimated that it will be completed in 5 to 20 minutes.

[0043]

The ion-selective electrode of the present invention can measure a plurality of ions by using a single working electrode. This provides the advantage that different types of target ions can be measured with a single electrode, for example, in the field of clinical examination, Na ^+, which is important as an electrolyte in body fluid, and Li ⁺ , which is associated with psychosis, can be measured. Thus, by using the ion-selective electrode of the present invention, the whole measurement system can be made compact and simple, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a model showing a photodimerization reaction of a calixarene derivative used in the present invention.

FIG. 2 is a flow chart outlining a method for synthesizing a calixarene derivative used in the present invention.

FIG. 3 shows a typical example of a potential measuring device to which the ion-selective electrode of the present invention is applied.

FIG. 4 is a diagram showing a configuration of a working electrode according to the present invention.

FIG. 5 is a graph showing how the selectivity coefficient reversibly changes when light irradiation is repeated in the ion selective electrode according to the present invention.

[Explanation of symbols]

 1 Electrometer 2 Working Electrode 3 Standard Electrode (Reference Electrode) 4 Salt Bridge 5 Sample Solution 6 Saturated Potassium Chloride Solution 11 Silver Wire 12 Electrode Holder 13 Internal Standard Solution 14 Membrane 15 Optical Fiber

Claims (1)

[Claims] 1. 25-position and 27-position, or 26
A calix [4] arene derivative substituted at the 9- and 28-positions with a 9-anthryloxy-ethyl group was used as a neutral carrier in a polymer containing a plasticizer having no absorption spectrum overlapping with anthracene. An ion-selective electrode, wherein a film-like material obtained by dispersion is used as a working electrode.