JPH0476442A - Chemical substance sensor - Google Patents

Abstract

PURPOSE:To perform measurement with a high degree of reproducibility for a long period by separately laminating a sensor film containing a chemical substance sensitive compound and a pigment film containing pigments for detecting a variation in film physical characteristic in the form of a variation in light reflectivity, one upon another. CONSTITUTION:A pigment film 13 and a sensor film 12 are separately formed successively on a transparent substrate 11, and a light emitting element 21 and a light receiving element 22 are set on the rear surface of the substrate 11. Further, the film 12 contains, as a stabilizer more than one kind of material selected from a metal complex, a phenol group, a hindered amine group and an amine group in addition to a chemical substance sensitive compound which is selected in accordance with a chemical substance to be detected, so as to prevent the pigment from being deteriorated by oxygen, the chemical substance to be detected, ultraviolet rays or the like included in the ambience under use. Further, the chemical substance sensitive compound in the film 12 changes its film physical characteristic by being bonded with the chemical substance to be detected so as to change the light reflectivity of the film 13 laminated on the film 12, in particular the mirror-surface reflectivity, thereby a quantity of the chemical substance to be detected is measured. Thus, it is possible to measure the chemical substance with a high degree of reproducibility and a high degree of accuracy for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a chemical substance sensor capable of detecting and quantifying chemical substances.

<Conventional technology> It selectively adsorbs or selectively reacts with specific chemical substances existing in the outside world, and the type and concentration of the chemical substance can be determined from the resulting changes in electrical signals such as resistivity and dielectric constant. Chemical sensors for detection are known.

Such chemical sensor materials include semiconductors, ceramics, polymers, etc., and are actually applied to the detection and quantification of water vapor, various gases, various ions, etc.

Additionally, sensors using cholesteric liquid crystals are known [JP-A-53-76094, JP-A-58-426].
No. 85, Tsukahara, Mechatronics special issue, iyudan, 10
3 (1981) Sensor Technology, 1-"-Eng. 1, 62 (
1987) Same as: LLLLl, 97 (1987)
, 7(12).

87 (1987)].

This device utilizes the color change of liquid crystal.

On the other hand, with the recent development of office automation equipment, etc., there is a demand for various sensors that can operate stably and accurately even in environments with strong electric fields such as copying machines, so sensors that use optical detection and quantitative methods are advantageous. It is.

Among these, optical methods utilize the change in the amount of light absorption or fluorescence (fluorescence quenching) caused by the reaction of certain dyes or compounds with gas substances or the formation of charge transfer complexes. Detection and quantitative methods are known.

For example, one that utilizes the discoloration caused by the reaction between N,N-dimethylaniline and 02 (Japanese Unexamined Patent Application Publication No. 100337/1982) Poly-2-para (mekkuroylaminophenyl)-5-
A method that utilizes discoloration caused by the reaction of phenyl-1,3-oxazole with NH3 or amines (Japanese Patent Laid-Open No. 60-202
334), tris(4,7-diphenyl-1,10-
There is a method (Japanese Unexamined Patent Publication No. 178646/1983) that utilizes the change in fluorescence caused by the reaction between Ru complex (phenanthroline) and 02.

Furthermore, a method utilizing absorption change in bromothymol blue film due to NH (Nikkei Sangyo Shimbun, December 1988)
(Published on the 14th of May), NO.

[Chemical Society of Japan Spring Annual Meeting Proceedings 3 II H07 (1988) Nikkei Sangyo Shimbun, published June 10, 1988] etc. can also be mentioned.

Although there are few examples of devices that utilize light reflection, devices that use metal films or metal salts are being considered.

For example, those utilizing the reaction of palladium potassium sulfite and CO (Japanese Patent Application Laid-open No. 79141/1983), Hg B
These include a method that utilizes the reaction between r x and As Hs (Japanese Patent Laid-Open No. 60-42645), and a method that utilizes corrosion of a metal film by SF (Japanese Patent Laid-Open No. 62-8066).

Furthermore, as a humidity sensor, an optical fiber or one that uses a change in refractive index by providing a hygroscopic material as a cladding on an optical fiber (JP-A-61-217744, JP-A-6
2-9255, JP-A No. 62-204143, etc.), those using inorganic compounds that change color due to moisture absorption (JP-A-54-80190, JP-A-61-139478)
, those that utilize changes in absorption coefficient, changes in scattering intensity, or color development due to hygroscopic resin etc. (Japanese Patent Laid-Open No. 56-67738)
No., JP-A-56-110039, JP-A-58-216
No. 936), and furthermore, one that utilizes changes in diffused reflection using a transparent body with unevenness and a moisture absorbent (Japanese Unexamined Patent Publication No. 59-1999)
204742), or one that utilizes reflected light and transmitted light from a mirror consisting of two types of dielectric layers having different refractive indexes (Japanese Patent Laid-Open No. 62-39744).

However, there are no proposals that utilize the reflection of a pigmented film.

Sensors using semiconductors, ceramics, polymers, etc. as described above generally have a drawback that the film is thick and the response is slow due to the diffusion process of the gas to be detected. Also, there are many things that need refreshing. Furthermore, changes in resistance values are often detected, and since this is done by electrical means, it is easily affected by strong electric fields and changes over time.

In addition, many of the device manufacturing methods involve complicated processes (
Many of the detection circuits and the like are also complicated.

On the other hand, sensors using cholesteric liquid crystals utilize color changes due to changes in pitch, so the wavelength distribution of light reflection varies in various ways, making them unstable, having low sensitivity, and being highly temperature dependent. , etc. have drawbacks.

In addition, when using changes in absorption or fluorescence using dyes, etc., there is a drawback that it is limited to dyes that can selectively bind or react with the analyte, such as a gas substance, to be detected or quantified. be. When manufacturing such devices, it is necessary to highly orient the dye molecules when applying the LB film, such as the one that utilizes the fluorescence change in the LB film mentioned above, and the absorption Advanced or? In many cases, complicated processes are required.

Furthermore, in the case of using a metal film or a metal salt, all reactions are irreversible, and even in this case, the combinations of the sensor material and the test substance such as a gaseous substance are limited.

In order to deal with the above problem, the present inventors previously developed the following method:
A chemical substance sensor comprising a dye and a chemical substance-sensitive compound, and configured such that the light reflectance of the film changes when the chemical substance-sensitive compound combines with a test chemical substance. ” (Patent Application No. 63-219434),
and "has a substrate, a sensor film formed on the substrate, a light emitting element and a light receiving element, the sensor film contains a dye and a chemical substance sensitive compound, and the chemical substance sensitive compound is a test chemical substance. A chemical substance characterized in that the chemical substance is configured such that the light reflectance of the film changes by binding, and the rapid change in light reflection is detected by the light receiving element to detect and quantify the chemical substance to be tested. sensor.'' (Japanese Patent Application No. 63-219921).

However, in this method, it is necessary to form the chemical substance-sensitive compound and the dye in the same film, which requires compatibility between them, which limits the number of test chemicals that can be tested. There is. Further, due to this, the content of the dye is limited, resulting in a problem that sufficient detection sensitivity cannot be obtained.

For this reason, the present inventors further proposed that the sensor film has a substrate and a dye film laminated on the substrate, the sensor film contains a chemical substance-sensitive compound, and the chemical substance-sensitive compound is a test chemical substance. "A chemical substance sensor" (Japanese Patent Application No. 1-212792) characterized in that the light reflectance of the dye film is changed by combining with the chemical substance sensor.

By separating the dye film and sensor film in this way,
A wide selection of chemical substances to be tested (and a chemical substance sensor that has high precision in detection and quantification, quick response, easy element configuration, excellent durability, and is advantageous in terms of cost) It is possible.

<Problems to be Solved by the Invention> In a chemical substance sensor having a structure in which a dye film is sandwiched between a substrate and a sensor film, light irradiation and detection of the reflected light can be performed from the back side of the substrate, and the dye film Since there is no direct contact between the dye and the test chemical, deterioration of the dye can be suppressed.

However, pigments tend to deteriorate when exposed to oxygen for long periods of time (
In addition, it may deteriorate due to exposure to chemical substances to be tested such as water vapor, ultraviolet rays, etc. Since the sensor film transmits these to some extent, the reflectance changes over time due to dye deterioration, making it difficult to realize a sensor that provides stable measurement values over a long period of time.

The present invention has been made under these circumstances, and provides a chemical sensor having a structure in which a dye film and a sensor film are separated, and which can provide highly reproducible measurement values over a long period of time. The purpose is to

<Means for Solving the Problems> The above objects are achieved by the following inventions (1) to (3).

(1) having a dye film on the substrate, having a sensor film on the dye film, the sensor film containing a chemical substance sensitive compound;
A chemical substance sensor, characterized in that the chemical substance sensitive compound is configured to change the light reflectance of the dye film by binding with a test chemical substance, and the sensor film contains a stabilizer.

(2) The chemical sensor according to (1) above, wherein the stabilizer is one or more selected from metal complexes, phenols, hindered amines, and amines.

(3) The above (3) further comprises a light-emitting element and a light-receiving element, and the light-receiving element detects a change in light reflectance through the base of the pigment film, thereby detecting and quantifying the test chemical substance. The chemical sensor according to 1) or (2).

<Function> The chemical substance sensor of the present invention has a dye film on a substrate and a sensor film on the dye film.

The sensor film contains a chemical-sensitive compound, and this chemical-sensitive compound changes the physical properties of the film by combining with the test chemical, and this change in the physical properties of the film changes the light reflectance of the dye film laminated on the sensor film, In particular, the specular reflectance is changed, and the amount of the test chemical substance is measured based on this change in reflectance.

In the chemical substance sensor of the present invention, the sensor membrane contains a stabilizer.

This stabilizer has the effect of preventing dye deterioration by quenching doublet oxygen, blocking and absorbing ultraviolet rays, capturing oxygen radicals, decomposing peroxide, etc. Since the dye is prevented from deteriorating due to oxygen, test chemicals, ultraviolet rays, etc., an extremely stable sensor can be obtained.

Specific composition> Hereinafter, the configuration of the present invention will be explained in detail.

In the present invention, the sensor film is formed on the substrate in a laminated state with the dye film.

In this way, in the present invention, since the sensor film and the dye film are separately laminated,
34 and No. 63-219921, in which a chemically sensitive compound and a dye are contained in the same film, there is no consideration of compatibility between the chemically sensitive compound and the dye. . Therefore, the content of the dye in the dye film can be increased, the change in reflectance of the dye film becomes sufficient, and sufficient sensitivity can be obtained. Furthermore, desired sensitivity can be obtained by controlling the thickness of the dye film.

In the chemical substance sensor of the present invention, a dye film and a sensor film are formed in this order on a substrate.

By forming the structure as described in 2, it is possible to detect from the back side of the substrate, and the sensitivity is improved because the test chemical substance comes into direct contact with the sensor film. will become even less.

The pigmented film in the present invention has a specular reflectance of 10% or more, more preferably 20% or more when measured at an angle of 20' or less, particularly 5@, in any wavelength from the visible to infrared region. , it is preferable to have so-called bronze luster. Note that the angle in this case is an angle with respect to the normal line of the film surface.

In addition, the dye film in the present invention has an absorption rate of 70% or less, preferably 50% or less (the maximum wavelength of reflection (λR3,) in the pigment film is the maximum wavelength of absorption (λA
□. ), and in particular, χR
It is desirable that □8−λA□8≧50 nm.

By using such a dye film, substantially sufficient sensitivity can be obtained. This is because when the reflectance is less than 10%, it becomes difficult to detect the test chemical substance as a change in reflectance.

By measuring the reflectance by specular reflection of 20° or less, sensitivity is increased and the device can be made more compact.

The pigment that makes up such a pigment film has a reflectance of 1.
There is no particular restriction as long as it is 0% or more, but specific examples include cyanine dyes, azulenium dyes, biryllium dyes, squarylium dyes, croconium dyes, quinone/naphthoquinone dyes, metal complex dyes, phthalocyanine dyes, naphthalocyanine dyes, etc. It will be done.

In addition, when using polymethine dyes such as cyanine dyes, -doublet oxygen quenchers may be mixed and used,
The quencher in this case is a metal complex, especially Ni
Complexes such as dithiol-based (particularly bisphenyldithiol-based) Ni complexes and amine compounds are preferred.

Further, an ionic combination of a quencher anion and a cyanine dye cation may be used.

Among these dyes, ionic combinations of quencher anions and cyanine dye cations, dyes and singlet oxygen quenchers, etc. have good water resistance and are stable against deterioration due to oxidation. It is preferable to use a mixture of phthalocyanine dyes, phthalocyanine dyes, and the like. Note that since these dyes are soluble in organic solvents other than alcohol, the present invention exhibits particularly high effects when these dyes are used.

The chemical substance sensitive compound contained in the sensor membrane in the present invention is a compound that binds to a specific chemical substance reversibly or irreversibly, and may be selected depending on the test chemical substance.

More specifically, chemically sensitive compounds have various bonding states between their molecules and the target chemical substance to be tested, and these bonds include various reactions, covalent bonds, ionic bonds, etc. In addition to various bonds such as , coordinate bonds, adsorption, absorption, etc. are included.

The binding and desorption between the chemical substance-sensitive compound and the test chemical substance is preferably reversible, but may be irreversible.

When the test chemical substance is water, a hydrophilic compound is used as the chemical substance-sensitive compound.

The sensor membrane containing a hydrophilic compound has a water vapor diffusion constant of 10810 cm/sec or more, especially 50
It is preferable that it is 10-"cta" 7 seconds or more. If the water vapor diffusion constant is less than the above range, the sensor film is likely to undergo deformation such as swelling, and the reproducibility of reflectance tends to be poor.

In addition, the water vapor diffusion constant is determined by determining the moisture permeability according to JIS Z 020g, and from this "Materials and Moisture Handbook".
(Polymer Compounds, Kyoritsu Shuppan) P, 193-218.

When the sensor membrane is composed of a single hydrophilic compound, the water vapor diffusion constant of the sensor membrane is approximately equal to the water vapor diffusion constant of the hydrophilic compound that is the material. In addition, when the sensor membrane is composed of two or more types of hydrophilic compounds,
The water vapor diffusion constant can be determined according to the method described above.

Specific examples of hydrophilic compounds include the following.

■, Hydrophilic polymer compound A hydrophilic polymer compound having a polar group is preferred.

Examples of polar group-containing polymer compounds include oxygen-containing polymer compounds such as carbonyl groups and ether groups, and NH group-containing polymer compounds, as well as polymer compounds containing cyano groups, halogens, etc. There is something.

a) Water-absorbing polymeric anion salt (particularly a salt that reversibly absorbs water) For example, sodium alginate, rum, sodium polyacrylate, sodium polymethacrylate, sodium poly(4-styrenesulfonate), sodium polyvinyl phosphate , polyvinylphosphorus ammonium, sodium polyglutamate, etc.

b) Polyelectrolytes such as polyethyleneimine hydrochloride, polyethyleneimine/polystyrene sulfonic acid, polyN-methylpyridinium chloride, etc.

C) Thermosetting resins phenolic resins, furan resins, alkyd resins, epoxy resins, melamine resins, unsaturated polyester resins, etc.

d) Thermoplastic resin polyvinyl acetate, polyacrylate, polymethacrylate, polyvinyl chloride, polyacrylonitrile, polyvinyl alcohol, polyether, polyamide, polyester, polyurethane, polyvinyl ketone, polyvinylidene chloride, polyvinylpyrrolidone (PVP), polyalkylene ( ethylene) glycol, polyacrylamide, PV
A-ethylene copolymer, etc.

e) Cellulose-based acetylcellulose, triacetylcellulose, nitrocellulose, acetylbutylcellulose, propionylcellulose, ethylcellulose, carboxymethylcellulose, etc.

f) Natural polymers and their derivatives casein, amylose, polyglycine, modified starch (
grafted starch) etc.

g) These blends or copolymers may be crosslinked to have a three-dimensional structure.

These polymer compounds are preferably used because they have good film properties and high water resistance.

II, hydrophilic low-molecular organic compound h) Water-absorbing organic metal salt (especially a salt that absorbs water reversibly) For example, sodium acetate, sodium potassium tartrate,
such as sodium lactate.

II+, hydrophilic inorganic compounds i) water-absorbing inorganic metal salts (especially salts that absorb water reversibly), for example LiC11, Ca CIlz, Co Ci!
, metal halides such as w.

j) Hydrophilic gels, such as colloidal silica or silicates such as silicon alkoxides, hydrolysates of titanates, aluminates, zirconates, etc.

One or more of these compounds may be used, and a humidity sensor that detects water vapor can be obtained.

Among these hydrophilic compounds, preferred compounds in terms of water vapor diffusion constant are shown below.

Acetyl cellulose 52 x 10-'cm'/sec Ethyl cellulose 71 x 10-'cm'/sec Triacetyl cellulose 77 x 10-'cm'/see Acetyl cellulose 114 x 10-'cm'/sec Bo] Morifit' alcohol-soluble nylon (terpolymer of 6/6.6/6.10 nylon, etc.) 3 0 X 10-"cm"/sec Next, when using ammonia as the test chemical substance, bromothymol blue, thymol blue, acridine orange, poly-2-para(methacroylaminophenyl)-
5-phenyl-1,3-oxazole or the like may be used as the chemical substance-sensitive compound.

Furthermore, crown ether is used when the chemical substance to be tested is ions of alkali metals or alkaline earth metals such as Na''' and K4, and various metal ions such as Ag''.

As a crown ether, benzo-15-crown 5
(test chemical; Na'''), dibenzoviridino 18
- Crown-6 (test chemical; various metal ions) Cryptofix 222CC (manufactured by Merck) (test chemical; 0), Azacrown ether with long chain introduced (test chemical, Ag''') ( For example, etc.) can be used.

In addition, cholesteric liquid crystal is used for various gases, pyrene is used for O3 as a test chemical substance,
N,N-dimethylaniline, tris(4,7-diphenyl-1,10-phenanthroline) Ru complex, (CI2
CH1CHilaS or (CI2.CHz CHx)
*Triphenylmethine neutral red and the like are examples of substances that use NH as the test chemical substance.

In the present invention, the sensor membrane contains a stabilizer in addition to the chemical substance-sensitive compounds described above.

As the stabilizer, it is preferable to use one or more selected from metal complexes, phenols, hindered amines, and amines.

As the metal complex, a transition metal complex is preferred. In this case, the central metals include Ni, Co, Cu, Mn, and P.
d, Pt, etc. are preferred, especially acetylacetonate-based, bisthio-α-diketone-based, bisphenyldithiol-based, dithiocarbamate-based, thiocatechol-based, salicylaldehyde oxime-based, thiobisferulate-based, and phosphorous acid-based It is preferable to use one or more metal complexes such as the following.

As phenols, bisphenol A, 4-t-butylphenol, 2.6-dimethylphenol, 2.4
-Dimethyl-6-t-butylphenol and the like are preferably used.

As the hindered amines, it is preferable to use one or more types such as 2,2,6°6-tetramethylbiperidine derivatives.

Examples of amines include tetraphenylphenylenediamine or its salt, phenyl-β-naphthylamine, 1.2
-Bis-phenylamino-ethane and the like are preferably used.

In addition to these, phosphites such as triethyl phosphite, sulfur-containing compounds such as 4-t-butylthiocresol, various benzophenone derivatives, etc. can also be used as stabilizers.

There is no particular limit to the content of stabilizer in the sensor membrane;
It may be selected as appropriate from a range in which the effect of the stabilizer is fully exhibited, the sensitivity as a sensor film does not decrease significantly, and the stabilizer can be dissolved or uniformly dispersed.
．． It is preferably 1 to 50 wt%, particularly 1.0 to 30 wt%.

In the present invention, as described above, the light reflectance of the dye film laminated on the sensor film changes due to the combination of the chemical substance-sensitive compound and the test chemical substance in the sensor film. Detecting chemical substances.

The change in light reflectance in this case is considered to be due to changes in film properties such as film thickness, film density, and refractive index, as described above.

That is, in the present invention, changes in film physical properties in response to the bond between a chemical substance-sensitive compound and a test chemical substance are detected by changes in the light reflectance of a dye film that exhibits high specular reflectance, and the test chemical substance is quantified. It is something.

More specifically, it is thought that in hydrophilic compounds such as hydrophilic polymer water-absorbing salts and hydrophilic gels, hydration occurs due to water vapor, and water is adsorbed or absorbed.

In addition, it is thought that this is due to some kind of interaction between bromothymol blue and ammonia, and ultimately the formation of a charge transfer complex.

In the case of crown ethers, this is thought to be due to inclusion of ions such as alkali metals and alkaline earth metals.

The above bond may be reversible or irreversible as long as it changes the light reflectance of the film. However, from the point of view of repeated use of the sensor, it is preferable that the sensor be reversible.

Although it is possible to use only the change in light reflectance as described above,
In some cases, light transmittance can also be used.
Furthermore, in addition to changes in reflectance and transmittance with monochromatic light, it is possible to provide a range of measurement wavelengths and detect changes in the amount of reflected light or transmitted light. In this case, an LED can be used as the light source, and the amount of light that changes is large (which is preferable).

In such a case, as described above, it is preferable to use specular reflection.

The dye film in the present invention may be composed only of the dye, or may contain a binder such as a self-oxidizing resin such as nitrocellulose, or a thermoplastic resin such as polystyrene or nylon. The pigment content in this case is 60
The content is preferably 90 to 100 wt%, preferably 90 to 100 wt%.

With such a content, changes in the physical properties of the film can be sufficiently reflected in the light reflectance of the dye film.

Further, the thickness of the dye film may be selected depending on the desired sensitivity, etc., and is approximately 400 to 200 OA.

When the sensor film in the present invention can be formed from only a chemical substance sensitive compound and a stabilizer, it may be formed from only these, which is a preferred embodiment.

Specifically, in the case of a humidity sensor, a coating film having good physical properties can be obtained, especially when a hydrophilic polymer compound is used in the above examples.

In addition, when using ammonia as the test chemical, poly-
The same applies to 2-para(methacroylaminophenyl)-5-phenyl-1,3-oxazole and the like.

Note that for other compounds, the film may be formed by coating or the like.

It is also possible to create a sensor film by using similar chemical substance sensitive compounds in combination.

In this case, for example, a polymer chemical-sensitive compound may have a binder function.

Furthermore, binders such as various polymers that do not inhibit the function as a chemical substance-sensitive compound may be used in combination.

The total content of chemically sensitive compounds and stabilizers in the sensor membrane is between 50 and lo.

The content is preferably 80 to 100 wt%. With such a content, the physical properties of the sensor film can be sufficiently changed.

In addition, the sensor membrane in this case should have a thickness of 0.05 to 100 μ, preferably 0.1 to 5 (more preferably 0.01 to 1, especially 0.08 to 0.25 μ). In this way, it is possible to form a thin film, and the response as a sensor becomes faster.

Furthermore, the product of the water vapor diffusion constant of the sensor membrane described above and the thickness of the sensor membrane is 0.5X10-''~1, OX1
Preferably, it is 0-"cm"/see. By setting the product of both within this range, the moisture resistance of the sensor film becomes extremely high.

The material of the substrate in the present invention is not particularly limited, but it is preferably substantially transparent. This is because detection can be performed from the back side of the base.

Specifically, glass, hard vinyl chloride, polyethylene terephthalate (PET), polyolefin, polymethyl methacrylate (PMMA), acrylic resin, epoxy resin, polycarbonate resin, polysulfone resin,
Examples include various resins such as polyether sulfone, methylpentene polymer, and bisphenol A-terephthalic acid copolymer.

The shape of such a substrate is not particularly limited, but it is usually plate-like or film-like.

In order to manufacture the chemical substance sensor of the present invention, a dye film may be formed on a substrate, and a sensor film may be layered thereon.

The dye film and the sensor film may be formed by preparing a dye coating solution and a chemical substance-sensitive compound coating solution, respectively, and forming the coating films. At this time, a stabilizer is included in the coating solution of the chemical substance-sensitive compound.

Application during coating film formation may be performed by spin cord, dipping, spraying, or the like.

In the present invention, there is no restriction on the solvent used when preparing each coating solution for the dye film and the sensor film.When forming the dye film, the solvent may be selected from those in which the dye is soluble. The stabilizer may be selected from those in which the chemical substance-sensitive compound is soluble and the stabilizer is soluble or the stabilizer is uniformly dispersed.

Specifically, for example, keto alcohols (aliphatic keto alcohols, especially diacetone alcohol, acetol, acetoin, acetoethyl alcohol, etc.), R,0-R,
-OH [Here, R+ is a lower alkyl group (especially with 1 to 5 carbon atoms), R is a lower alkylene group (especially with 2 carbon atoms)
~5). ]; ketone systems such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester systems such as butyl acetate, ethyl acetate, carpitol acetate, and butyl carpitol acetate; ether systems such as methyl cellosolve and ethyl cellosolve; toluene; Examples include aromatic systems such as xylene, halogenated alkyl systems such as dichloroethane, water, and alcohols.

Under these circumstances, when a water-absorbing polymeric anion salt serving as a humidity sensor is used as a chemical substance-sensitive compound, a sensor membrane can be produced by the following method.

That is, the chemical substance sensitive compound has an anionic group,
In the case of a soluble salt having a positive counter ion such as Na, NH, etc. that pairs with this anion group, after forming a coating film as described above, the positive counter ion is exchanged with the salt and at the same time the metal It is possible to introduce a halide into the film.

By making such a soluble salt insoluble through salt exchange, the stability of the coating film is improved, such as being extremely stable against moisture of the test chemical substance. Further, by leaving an excess amount of metal halide such as CaCβ2 in the coating film, the function as a sensor film can be improved.

Therefore, it is necessary that metal halides such as CaCβ2 exist in this form in the coating film, and it can be used by immersing it in a salt exchange solution and then drying it as is, or after exchanging it, washing it with water or a purified solvent, and then salting it again. It may also be immersed in another salt solution of similar composition to the exchange fluid.

The solution of CaCβ2 etc. used for salt exchange is 1 to 10 wt%,
Preferably it is 2 to 5 wt%.

As the solvent used for the salt exchange solution, the same ones as the coating solvent can be mentioned. However, it is necessary that the polymeric anion salt and the substrate obtained by salt exchange are hardly soluble and can dissolve the salt of the counter ion to be subjected to salt exchange.

Salt exchange may be performed at a temperature of 0 to 60°C for about 1 to 60 minutes.

The film thickness in this case is 0.05 to 0.1-, but CaC
It can be appropriately selected depending on the amount of β2, etc.

Furthermore, when an anion salt of a hydrophilic (water-soluble) dye is used as the dye, salt exchange can be performed in the same manner as above to lower the solubility in water and improve the water resistance.

In the present invention, the dye film and sensor film may be formed by vapor deposition.

That is, it may be carried out according to a known method using a dye or a chemical substance-sensitive compound as a vapor deposition source.

Examples of dyes that can be applied to the vapor deposition method include phthalocyanine dyes, naphthalocyanine dyes, squarylium dyes, and croconium dyes.

In the present invention, an air-sanding protection plate may be provided on the membrane surface of the sensor membrane, or an air-permeable protection plate may be provided on the membrane surface.

Further, a filter through which a specific chemical substance can pass may be provided on the membrane surface.

In the present invention, after forming the dye film and sensor film on the substrate, this may be punched or cut into desired dimensions. This method is preferable in terms of mass productivity.

Alternatively, a glass fiber may be used as the base, and a dye film and a sensor film may be formed on the end face thereof.

Furthermore, a plurality of these materials may be bundled and used. Alternatively, the end faces may be polished after being bundled, and a dye film and a sensor film may be formed on the end faces.

In the chemical substance sensor of the present invention, it is possible to control the film thickness of the sensor membrane, and by bringing it into contact with a test fluid containing a test chemical substance, the test chemical substance (pI) can be adjusted according to the film thickness.
It becomes possible to measure in the range of b to 100%.

A preferred embodiment of the chemical substance sensor of the present invention includes, for example, a chemical substance sensor having the configuration shown in FIG.

In this device, a dye film 13 and a sensor film 12 are sequentially formed on a transparent substrate 11, while a transparent substrate 1
A light-emitting element 21 and a light-receiving element 22 are installed on the back side of 1, and these elements are housed integrally in a casing 30.

Therefore, the light emitted from the light emitting element 21 is incident on the back surface of the base 11, and the specular reflectance of the light at this time is captured by the light receiving element 22, which is also provided on the back surface of the base 11, and from the change in reflectance, the test chemical is detected. Detection and quantification.

In this case, it is preferable that the light-emitting element 21 and the light-receiving element 22 be installed close to each other, and by measuring reflection by specular reflection of 20" or less, especially 5 degrees or less, sensitivity is increased and the element can be made more compact. can be measured.

The wavelength of the light emitted by the light emitting element 21 in the present invention is in the visible to infrared range.

The light emitting element 21 is not particularly limited, but is preferably a light emitting diode (LED), a laser diode (LD), or the like.

Further, the light receiving element 22 is not particularly limited, but is preferably a photodiode, a phototransistor, or the like.

In addition, the chemical substance sensor of the present invention is not particularly limited in its structure as long as the sensor film and the dye film are laminated, and various embodiments are possible.

<Example> Hereinafter, the present invention will be specifically explained with reference to Examples.

[Example 1] A 2.0 wt% methanol solution of the pigment was applied onto a glass substrate (50 x 50 x 1 mm) using a spin cord, dried at 70°C for 30 minutes, and then calcium-substituted. A dye film was formed.

The thickness of the dye film after drying was 0.08-.

On this pigment film, a viscosity of 27±IOSEC (ASTM-A
) Coating/8 solution, which is a 2 wt % cyclohexanone solution of acetyl cellulose with a stabilizer added thereto, was coated with a spin cord and dried to form a sensor film. The thickness of the sensor film after drying was 0.15μ.

As a stabilizer, the product name P of Mitsui Toatsu Fine Co., Ltd.
Using A-1006 [Ni-bis(trichlorobenzenedithiol)tetra(t-butyl)ammonium], a 2 wt% solution of acetylcellulose in cyclohexanone 10
The stabilizer was mixed at a ratio of 0.5 parts by weight to 0 parts by weight.

A humidity sensor having the configuration shown in FIG. 1 was assembled using a glass substrate on which a dye film and a sensor film were formed.

Note that the light emitting element has an L that emits light with a wavelength of 950 nm.
An ED was used, and a PIN diode was used as a light receiving element.

After the humidity sensor thus produced was left in an environment of 60° C. and 90% RH, humidity measurement (reflectance measurement) was performed at room temperature and 2% RH.

FIG. 2 shows the relationship between the standing time and the reflectance (output voltage).

[Comparative Example 1] A humidity sensor was formed in the same manner as in Example 1, except that no stabilizer was included during the formation of the sensor film.

Regarding this temperature sensor, humidity measurements similar to those in Example 1 were performed.

The results are shown in Figure 2. In FIG. 2, the vertical axis indicates relative reflectance, and the initial reflectance is 1.0 in both Example 1 and Comparative Example 1.

From the results shown in FIG. 2, the effects of the present invention are clear. That is, in the humidity sensor of the present invention produced in Example 1, only about a 10% decrease in reflectance was observed even after 1000 hours of storage, whereas in the humidity sensor produced in Comparative Example 1, the reflectance decreased after 1000 hours of storage. The rate has fallen by about 24%.

A humidity sensor was prepared in the same manner as in Example 1 except that LA-57 (hindered amines) manufactured by Adeka Argus was used as a stabilizer, and the humidity was measured in the same manner as above. The reduction in humidity was about 15%, which was an improvement over the humidity sensor of Comparative Example 1.

Similar effects were also observed when other various stabilizers were used.

From the above results, the effects of the present invention are clear.

<Effects of the Invention> The chemical substance sensor used in the present invention is used to detect and quantify chemical substances in a test fluid.

In this case, a sensor film containing a chemical-sensitive compound that binds to a chemical substance and a dye film containing a dye to detect changes in the film physical properties of the sensor film as changes in light reflectance are separately laminated. Therefore, there is no need to consider the compatibility between chemical substance-sensitive compounds and dyes.

Therefore, a uniform thin film can be obtained, the response as a sensor is fast, and the reflectance can be kept high, resulting in high accuracy.

Furthermore, measurement can be performed from the back surface of the substrate, the measurable concentration range is wide, and the linearity is also good.

The element configuration is simple and can be made compact, and its manufacture is also easy.

That is, steps such as sintering and molding are not necessary, and electrodes and the like are also not required, which is advantageous in terms of cost.

In addition, since there is no electrical action such as transfer of electrons or voltage applied to the sensor membrane, there is little deterioration and it can withstand continuous use.

Furthermore, since the signal detection elements such as light emitting elements and light receiving elements can be placed isolated from the chemical substance to be tested, durability is also good from this point of view.

In the present invention, the dye film is disposed between the substrate and the sensor film, and the sensor film contains a stabilizer, so that deterioration of the dye film due to oxygen, test chemicals, ultraviolet rays, etc. in the usage environment is prevented. It can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a cut end view showing a preferred embodiment of the chemical substance sensor used in the present invention. FIG. 2 is a graph showing the relationship between storage time and reflectance when a humidity sensor is left in an environment of 60° C. and 90% RH. Explanation of symbols 1...Chemical substance sensor 11...Base 12...Sensor film 13...Dye film 21...Light emitting element 22...Light receiving element 30...Casing FIG, 1

Claims (3)

[Claims] (1) having a dye film on the substrate, having a sensor film on the dye film, the sensor film containing a chemical substance sensitive compound;
A chemical substance sensor, characterized in that the chemical substance sensitive compound is configured to change the light reflectance of the dye film by binding with a test chemical substance, and the sensor film contains a stabilizer. (2) The chemical sensor according to claim 1, wherein the stabilizer is one or more selected from metal complexes, phenols, hindered amines, and amines. (3) A claim further comprising a light-emitting element and a light-receiving element, the light-receiving element detecting a change in light reflectance through the base of the pigment film, and detecting and quantifying the chemical substance to be tested. 2. The chemical substance sensor according to 1 or 2.