JPH08152423A - Odor sensor - Google Patents

Abstract

PURPOSE: To speedily and accurately detect odor with a compact and easily handled sensor by forming a water-retaining layer with a polymer with a high water-containing property. CONSTITUTION: When an odor molecule 7 exists in the air, the odor molecule 7 is dissolved in a buffer liquid within a water retention layer 5 and then is adsorbed by a lipid film 3 and changes the film potential of the lipid film 3. The potential change of the lipid film 3 appears as the potential change (V0 →V1 ) between a metal electrode 2 and a reference electrode 4 at a pair of output terminals 6. Since the potential change ΔV=V1 -V0 is constantly correlated with the concentration of an odor substance in the air, the concentration of the odor substance can be detected by measuring the change ΔV. In this case, since the amount of high water-containing solution contained in the water retention layer 5 is extremely small, the odor molecule 7 is quickly dissolved and adsorbed by the lipid film 3 for speedy and accurately measurement. Also, only a small amount of odor substance is required for generating film potential and a container with water solution needs not be handled, thus enabling a sensor to be handled easily and compact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an odor sensor for detecting various odors vaporized in a gas phase, and makes it possible to detect this odor in a small size at high speed and with high sensitivity. .

[0002]

2. Description of the Related Art Conventionally, as an odor sensor, as shown in FIG. 2, a lipid film 11b is formed on the surface of a metal electrode 11a such as silver.
To form a lipid membrane electrode 11 by dipping the lipid membrane electrode 11 together with the reference electrode 12 in an aqueous solution 13 in which the odorant is dissolved, It was a method of detecting a potential change.

[0003]

However, in the configuration of the odor sensor shown in the above-mentioned prior art, the aqueous solution 1 is basically used.
Since only odorous substances dissolved in 3 can be measured, it is necessary to dissolve the odorous substance in the gas phase in a large amount of the water phase when trying to measure the odorous substance in the gas phase, which is a normal form of odor, The response speed was slow and the detection sensitivity was low. In addition, the presence of the aqueous solution made it difficult to handle, and there was a limit to miniaturization.

The present invention has been made in view of the above-mentioned problems of the prior art, and is handled by forming a water-retaining layer made of a highly hydrous substance instead of an aqueous solution which has been conventionally required in a large amount. It is an object of the present invention to provide an odor sensor that is easy to use, compact, fast, and highly sensitive to detect odors.

[0005]

Means for Solving the Problems The constitution of the present invention for solving the above-mentioned problems is an odor sensor for detecting various odors vaporized in a gas phase by utilizing the sensitivity of the lipid membrane. A conductive electrode covering the surface, a reference electrode, a water retention layer formed of a highly water-containing polymer or the like arranged in contact with both electrodes, and an output connected to the conductive electrode and the reference electrode It is characterized by having a configuration including a terminal pair.

[0006]

According to the present invention, a water retaining layer made of a highly hydrous substance is provided in place of the aqueous solution which is present in a large amount. Therefore, the sensor can be easily handled, downsized, and the odor can be detected at high speed and with high sensitivity.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the odor sensor of the present invention. In FIG. 1, 1 is an electrically insulating substrate such as glass, 2 is a metal electrode formed on the electrically insulating substrate 1, and 3 is a metal electrode.
Is a lipid film formed on the electrically insulating substrate 1 so as to cover the metal electrode 2, 4 is a reference electrode formed on the electrically insulating substrate 1, and 5 is in contact with the lipid film 3 and the reference electrode 4. A water-retaining layer arranged and formed of a super absorbent polymer such as cross-linked polyvinyl alcohol (PVA), and 6 is a pair of output terminals connected to the metal electrode 2 and the reference electrode 4.

It should be noted that the water retaining layer 5 is soaked with an arbitrary buffer solution, and in a state where no odorant is given, a certain constant potential V0 is applied between the metal electrode 2 and the reference electrode 4 to the output terminal pair 6. Is output to.

In such a structure, when the odor molecule 7 exists in the air, the odor molecule 7 is dissolved in the buffer solution in the water retention layer 5 and then adsorbed on the lipid membrane 3 to change the membrane potential of the lipid membrane 3. Change. The change in membrane potential of the lipid membrane 3 is caused by the metal electrode 2
It appears on the output terminal pair 6 as a potential change (V0 → V1) between the reference electrode 4 and the reference electrode 4. This membrane potential change ΔV = V1 −V
Since 0 has a certain correlation with the concentration of the odor substance in the air, the concentration of the odor substance can be known by measuring the membrane potential change ΔV.

According to the odor sensor of the present invention, since the amount of the solution contained in the water retention layer 5 is extremely small, the odor molecules 7 are dissolved and adsorbed to the lipid membrane 3 very quickly, and the membrane potential is generated. It requires less amount of odorous substances. Moreover, since it is not necessary to handle the container itself containing the aqueous solution, the sensor can be easily handled.

[0011]

As described above in detail with reference to the embodiments, according to the present invention, a water retaining layer made of a highly hydrous substance is provided in place of the aqueous solution which is present in a large amount. Therefore, it is possible to realize an odor sensor that can be easily handled, can be miniaturized, and can detect an odor at high speed and with high sensitivity.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an odor sensor of the present invention.

FIG. 2 is a conventional example of an odor sensor.

[Explanation of symbols]

 1 Electrical Insulating Substrate 2 Metal Electrode 3 Lipid Membrane 4 Reference Electrode 5 Water Retaining Layer 6 Output Terminal 7 Odor Molecule

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Toko 2-3-8 Miwadai, Higashi-ku, Fukuoka-shi, Fukuoka Prefecture-2 (72) Inventor Gen Gen Matsuno 2-3-9-32 Nakamachi, Musashino City, Tokyo Yokogawa Electric Machinery Co., Ltd. (72) Inventor Kenta Mikita 2-932 Nakamachi, Musashino City, Tokyo Yokogawa Electric Machinery Co., Ltd.

Claims (1)

[Claims] 1. An odor sensor for detecting various odors vaporized in a gas phase by utilizing the sensitivity of a lipid membrane, comprising a conductive electrode whose surface is covered with a lipid membrane, a reference electrode, and both electrodes. An odor sensor comprising a water retention layer formed of a highly water-containing polymer or the like arranged in contact with each other, and an output terminal pair connected to the conductive electrode and the reference electrode.