JPH11248633A - Composition for odor detecting element and odor detecting element using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ordor detecting element in a small size and capable of being made an excellently portable sensor for detecting odor with high sensitivity approximated to the sense of small of human being. SOLUTION: The composition for an ordor detecting element contains a solution, which is formed by adding water to siloxane represented by the formula (where R1 -R4 are radicals selected out of groups of the same or mutually different chain hydrocarbon radicals having respective oxygen atoms, substituted or non-substituted phenyl radicals, hydrogen and halogen) and hydrolyzing and polymerizing/condensing the siloxane under acidic catalyst, surface active agent and fluorescent pigment, the surface active agent accounting for 5-50 wt.% of the total. The odor detecting element is provided with odor molecular adsorbing portions formed of the above-mentioned composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composition for an odor detection element used for detecting an odor and an odor detection element using the same.

[0002]

2. Description of the Related Art In recent years, odor sensors capable of objectively and easily detecting odors without relying on human sense of smell have been developed, and some of them have already been put into practical use in production of foods and cosmetics. It is being used in various fields such as process control, product development, odor inspection in the environmental field, and detection of toxic gas in the disaster prevention field.

[0003] A semiconductor sensor utilizing a change in electric resistance when a gas adheres to the surface of an oxide semiconductor, or a synthetic lipid membrane having a structure similar to an odor-receiving membrane in human olfactory cells is formed on the surface. The one using a coated quartz oscillator is a typical one, and in particular, the latter is called a quartz oscillator type and is attracting attention as a device that detects an odor in a form relatively similar to human olfaction.

However, this crystal oscillator type odor sensor captures the amount of odor molecules adsorbed on the film as a change in the frequency of the crystal oscillator. The higher the fundamental frequency of the crystal oscillator used, the higher the odor sensor. Although sensitivity can be improved, there is naturally a limit in increasing the fundamental frequency of the crystal unit, and there has been a problem that it is difficult to further increase the sensitivity.

[0005] Further, a method of detecting an odor using a surface active substance has also been reported. However, since it is an aqueous solution, there has been a problem that it is difficult to miniaturize the sensor and to make it portable, which is not practical.

[0006]

As described above, an odor sensor capable of objectively and easily detecting an odor without relying on human olfaction has been developed, but it is still comparable to human olfaction. High sensitivity has not been obtained.

[0007] The present invention has been made in view of such conventional circumstances, and it is possible to make a sensor having a small size and excellent portability, and to detect an odor with high sensitivity in a form closer to human smell. It is an object of the present invention to provide a composition for an odor detection element capable of producing an odor and an odor detection element using the same.

[0008]

Means for Solving the Problems The composition for an odor detecting element of the present invention comprises (A) a compound represented by the following general formula:

Embedded image (Wherein, R _{1 to} R ₄ are the same or different and each represent a group selected from the group consisting of a chain hydrocarbon group having an oxygen atom, a substituted or unsubstituted phenyl group, hydrogen, and halogen). A composition comprising a solution obtained by adding water to the represented siloxane and hydrolyzing and polycondensing the siloxane under an acidic catalyst, (B) a surfactant, and (C) a fluorescent dye, The above (B) surfactant is used for the entire 5
-50% by weight.

Here, the fluorescent dye is a carbocyanine dye, a styryl dye,
It is preferably at least one selected from the group consisting of rhodamine dyes, merocyanine dyes, oxonol dyes, coumarin dyes, and rhodocyanine dyes.

Further, the odor detecting element of the present invention is characterized in that
As described in the above, the present invention is characterized by including an odor molecule adsorbing portion composed of the composition.

Hereinafter, the present invention will be described in detail.

Specific examples of the siloxane represented by the general formula [I] of the component (A) used in the present invention include tetramethoxysilane, tetramethoxysilane, tetraphenoxysilane, methyltrimethoxysilane, methyltrimethoxysilane, and methyltrimethoxysilane. Ethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane,
Examples thereof include dimethyldiethoxysilane, trichlorosilane, and phenyltrichlorosilane. Of these, alkoxysilanes such as tetramethoxysilane and tetramethoxysilane are preferable. These siloxanes can be used alone or
Two or more kinds can be used as a mixture.

In the present invention, the ratio of such siloxane to water added for hydrolysis is important, and it is desirable that the ratio (siloxane / water) be in the range of 0.1 to 10 in molar ratio. , 1.5-4.5. The molar ratio of siloxane to water is less than 0.1 or 10
When the ratio exceeds the above range, the film formability of the composition of the present invention is reduced.

In addition, hydrochloric acid or the like is used as the acidic catalyst.

The surfactant of the component (B) may be any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant, and is not particularly limited. However, depending on the film forming conditions of the composition and the temperature conditions for detecting an odor, etc., not only the film forming property is reduced, but also the function of detecting the odor may be impaired. It is desirable to use

That is, as the anionic surfactant,

Embedded image Etc. are used.

Examples of the cationic surfactant include:

Embedded image

Embedded image

Embedded image Etc. are used.

As the amphoteric surfactant,

Embedded image Etc. are used.

As the nonionic surfactant,

Embedded image Etc. are used.

In the above formulas, X represents a group selected from the group consisting of hydroxy, halogen and -HSO ₄ , except where otherwise indicated.

Examples of the fluorescent dye of the component (C) include carbocyanine dyes, styryl dyes, rhodamine dyes, merocyanine dyes, oxonol dyes, coumarin dyes, and rhodocyanine dyes. However, carbocyanine dyes, merocyanine dyes, and rhodamine dyes are preferred. These can be used alone or in combination of two or more.

Specifically, carbocyanine dyes represented by the following general formula [II] and merocyanine dyes represented by the following general formula [III] are preferably used.

[0023]

Embedded image In the present invention, the component (B) is used in an amount of 5 to 50% by weight, preferably 5 to 35% by weight based on the total weight of the composition.
It is blended so that If the blending amount of the component (B) is less than 5% by weight, the odor detection function becomes insufficient, and if it exceeds 50% by weight, crystallization occurs.

The amount of the component (C) is desirably in a range in which the molar ratio (C) / (B) of the component (C) to the component (B) is 1 or less. When the molar ratio of (C) / (B) exceeds 1, not only does the film formability of the composition decrease, but also the odor detection performance decreases.

The composition of the present invention may contain, if necessary, alcohols, ketones, esters, acidic or basic solvents as long as the object of the present invention is not adversely affected.

The composition for an odor detection element of the present invention can be formed on a substrate made of glass or the like by a usual method such as a spin coating method or a dipping method, or coated on an optical fiber. , And can be used as an odor detection element. In other words, the membranes and particles thus formed adsorb odor molecules and change the membrane potential, similarly to the receptor membrane in human olfactory cells. Since the change in the membrane potential appears as a change in the fluorescence intensity of the fluorescent dye of the component (C), the fluorescence intensity of the film (or particles) when the odor molecules are adsorbed by ordinary optical means. By measuring the change, the odor can be detected. As will be described later, the odor detected in this manner is very similar to the sensory evaluation by a human, and a highly sensitive odor can be detected.

As described above, the composition for an odor detection element of the present invention can be formed into a film or formed into particles, and the formed film or particle has a highly sensitive odor detection function. ing. Since the odor detection element of the present invention includes the odor molecule adsorbing portion composed of such a composition, odor detection with high sensitivity comparable to human olfaction can be performed. An odor sensor having excellent sensitivity and high sensitivity can be obtained.

[0028]

Next, embodiments of the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

The structural formulas of the surfactant (dialkylammonium bromide) and carbocyanine dye used in each of Examples and Comparative Examples are shown below. In the following description, “parts” means “parts by weight”.

Dialkylammonium bromide:

Embedded image Carbocyanine dye:

Embedded image Examples 1 to 4 100 parts of tetramethoxysilane and 24 parts of ion-exchanged water were hydrolyzed and condensed for 60 minutes at room temperature in the presence of an acidic catalyst (pH 2 to 3). The dialkylammonium bromide and the carbocyanine dye were added, and uniformly stirred and mixed.

Next, this mixed solution was formed into a film on a slide glass by a spin coater at a rotation speed of 5000 rpm to prepare an odor detecting element.

Comparative Examples 1 to 3 A composition was obtained in the same manner as in the Example except that the amounts of the components were changed as shown in Table 1. Further, the composition was formed into a film on a slide glass and smelled. A detection element was manufactured. The characteristics of the odor detection elements manufactured in the above Examples and Comparative Examples were evaluated. The results are shown in Table 1.

In the property evaluation, the film formability is determined by visually judging the appearance (smoothness, transparency) of the coating film, and the correlation between the amount of change in the fluorescence intensity and the sensory evaluation. The number is the change in fluorescence intensity ΔF = (F1−) when 1 to 20 ppm of an organic odorant (toluene) is adsorbed on the odor detection element.
F0) / F0 (where F1 is the fluorescence intensity after odorant adsorption,
F0 is calculated from the fluorescence intensity before the adsorption of odorous substances) and the result of a sensory test based on the following evaluation score.

[Sensory Evaluation Score] 0: No odor 1: Low odor (feeling faint) 2: Medium odor (smell can be discriminated) 3: Strong odor 4: Strong odor that cannot be tolerated

[Table 1] As is clear from Table 1, the composition according to the present invention is excellent in film formability, and the detection of odor by the odor detection element produced using them has a high correlation with the sensory evaluation. ing.

[0035]

As described above, the composition for an odor detection element of the present invention has excellent film-forming properties, and can be used to detect odors with high sensitivity in good correlation with human sensory evaluation. A detection element can be obtained. Therefore, it is possible to provide an odor sensor that is small, has excellent portability, and has high sensitivity.

[0036]

Claims (3)

[Claims] (A) General formula (1) (Wherein, R _{1 to} R ₄ are the same or different and each represent a group selected from the group consisting of a chain hydrocarbon group having an oxygen atom, a substituted or unsubstituted phenyl group, hydrogen, and halogen). A composition comprising a solution obtained by adding water to the represented siloxane and hydrolyzing and polycondensing the siloxane under an acidic catalyst, (B) a surfactant, and (C) a fluorescent dye, A composition for an odor detection element, comprising the surfactant (B) in an amount of 5 to 50% by weight of the whole. 2. The composition for an odor detection element according to claim 1, wherein the fluorescent dye is a carbocyanine dye, a styryl dye, a rhodamine dye, a merocyanine dye,
A composition for an odor detection element, which is at least one selected from the group consisting of an oxonol dye, a coumarin dye, and a rhodocyanine dye. 3. An odor detection element comprising an odor molecule adsorbing part comprising the composition according to claim 1.