JPH01263537A - Fiber-shaped sensor and evaluating device thereof - Google Patents

Abstract

PURPOSE:To enable the rapid implementation of qualitative or quantitative analyses of a substance to be detected, by substituting a part of a clad element of a step index type multimode optical fiber by a substance showing a change in color through reaction with the substance to be detected. CONSTITUTION:In a step index type multimode optical fiber 3 composed of a clad material 1 and a core material 2, a part of the clad material 1 is replaced in the whole in the circumferential direction thereof by a substance 4 which shows a change in color through reaction with a substance to be detected. The optical fiber 3 used herein is constituted of glass, plastic, rubber or the like used as the core material and the clad material, and the removal of the part of the clad element is conducted by a method of cutting or the like. As for the substance substituted for this removed part of the clad material, the mixture of a biotic substance such as enzyme, antigen or antibody, a complex or the like with a color-developing substance such as oxidation-reduction dyestuff is used. Besides, fixation of these coloring substances to the removed part of the clad material is conducted by a coating method, an impregnating method or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fiber sensor and an evaluation device thereof. More specifically, the present invention relates to a fiber-like sensor used for quantifying and qualitatively determining a substance that reacts with a detection target substance and exhibits a color change, and an evaluation device thereof.

[Conventional technology]

Conventionally used methods for detecting various substances include chromatographic methods and colorimetric methods, which are often used for quantitative or qualitative purposes. In particular, chromatographic methods and colorimetric methods are mainly used for quantifying organic substances. There is.

However, these methods often require a pretreatment step to remove impurities, and therefore take a long time to perform measurements, and require expensive equipment such as chromatographs and spectrophotometers. need.

[Problem to be solved by the invention]

The present invention aims to shorten the detection process in detecting various substances, and to provide a detection means that uses various substances that react with the substance to be detected and exhibit a color change.

[Means to solve the problem]

Such an object of the present invention is achieved by a fiber-like sensor in which a part of the cladding of a step-index multimode optical fiber is replaced with a substance that reacts with a substance to be detected and exhibits a color change.

Three embodiments of the fiber-like sensor according to the present invention are shown in FIGS. 1(a) to 1(c), respectively. A portion of the material is replaced over its entire circumference (a and b) or partially (C) with a substance 4 that reacts with the substance to be detected and exhibits a color change.

The optical fiber used here is made of glass, plastic, rubber, etc., which are commonly used as materials for the core material and cladding material, and naturally, a material with a higher refractive index is selected and used as the core material material. Its dimensions include a core diameter of approximately 5 μm to 5 mm, a cladding thickness of approximately 1 μm to 1 mm, and a length of approximately 1 mm.
Generally, the core diameter is about 0.5 to 5 mm, and the length is about 1 to 10 cm if the purpose is to be disposable.

A portion of the cladding portion can be removed by any method such as cutting or melting, and the shape of the removed portion is not limited to that illustrated in FIG. 1, but may be any shape.

The substance to be replaced in the area from which the cladding material has been removed is a substance that reacts with the substance to be detected and exhibits a color change, and examples thereof include the following substances.

Mixtures of biologically related substances and complexes such as enzymes, antigens, antibodies, and antibiotics with chromogenic substances such as redox dyes, acid-base indicators, and natural dyes.Redox dyes, acid-base indicators, natural dyes, complexes, crystals,
Fixation of at least one kind of color-forming substance such as amorphous substance or liquid crystal to the removed part of the cladding material is as follows:
Any method can be used depending on the core material and the type of substance to be detected, such as a coating method, an impregnation method, a covalent bonding method, a vapor deposition method, and a sputtering method.

[Effect]

The fiber-like sensor according to the present invention applies the principle of evanescent waves. That is, when a medium with a high refractive index and a medium with a low refractive index are in contact with each other, when light passes through the medium,
Light travels through repeated reflections at the interface with a low refractive index medium, and during these reflections, the light enters the medium with a low refractive index in the very vicinity of the interface, and the evanescent wave formed by this intrusion is If the surface is colored, light absorption will naturally occur. Therefore, when comparing the intensity of the incident wave and the reflected wave, the reflected wave is weaker, and the darker the color, the weaker the intensity of the reflected wave.

Based on this principle, the part of the optical fiber from which the cladding material has been removed is replaced with a substance that changes color in response to changes in the substance to be detected in the outside world, in other words, changes in chemical and/or physical quantities. When light of a certain intensity is input from one end, the intensity of the emitted light corresponds to the color density of the color-forming substance, so it acts as a sensor that can indirectly quantify or qualitatively detect the target substance. It turns out.

A specific evaluation device using such a fiber-like sensor is shown in FIG.
It has a structure in which a light receiving element 8 is installed, and the fiber sensor 5 is fixed by being pushed between the source medium and the element (6-7 and 6'-8) at both ends and crimped. Therefore, for example, an elastic member such as a spring 9 is used on the light emitting element side.

The original medium is glass that is transparent or has a specific color,
Plastic, rubber, etc. are used with a thickness of about 0.1 to lOmIm. If the source medium itself is an elastic body, there is no need to use one elastic member and it can be configured with only one elastic member, but in other cases, a plate made of metal, plastic, rubber, etc. A shaped body, a block shaped body, a spring shaped body, etc. are generally used as the elastic member.

As the light-emitting element, for example, an LED of various wavelengths, a semiconductor laser, a white light emitter, etc. are used, and as the light-receiving element, for example, a diode is used.

〔Effect of the invention〕

By using a fiber sensor substituted with a substance that reacts with the substance to be detected and exhibits a color change, it becomes possible to quantitatively and qualitatively quantify the substance to be detected in a short period of time.

〔Example〕

Next, the present invention will be explained with reference to examples.

Example 1 A core part is formed of polymethyl methacrylate with a diameter of 2 mm+, and then coated with fluororesin to a thickness of 10 mm.
A cladding portion of μm was formed. A portion of the cladding material of the end-polished optical fiber (length 5cm) is 1cl! according to the shape shown in Fig. 1(a). It was cut and removed to a length of 1.

5 mQ of phosphate buffer with pH 7.8, 0.1 mM iodonitrosotetrazolium chloride dye, 10 enzyme units of xanthine oxidase, 20 enzyme units of nucleoside phosphorylase, sucrose stabilizer tg, 1% mercaptoethanol aqueous solution antioxidant 0.2 raf2 ．． 5 mg of polyvinyl alcohol (equivalent to 0.1%) and water were added to prepare an enzyme-dye solution having a total volume of 15 mQ.

This enzyme-dye solution was coated directly onto the removed portion of the cladding material, dried at 4° C. for 24 hours, and the removed portion was replaced with a 10 μm thick enzyme-dye mixture.

The fiber-like sensor produced in this way was
It was immersed for 1 second in an aqueous inosine solution of each concentration between 1 and 0.4 mM, and the dye was colored according to the redox change caused by the enzymatic reaction. Thereafter, it was attached to the evaluation apparatus shown in FIG. 2, and the change in light amount with respect to the concentration of the substance to be detected was measured as 8 power.

In this evaluation device, a polymethyl methacrylate plate with a thickness of 5 mm is used as the source medium, and an LE is used as the light emitting element.
D, a diode was used as a light receiving element, and an FRP striped spring was used as an elastic member, and changes in light amount were measured with a Bakumeter. The measured values were measured before and after coloring, and the graph in FIG. 3 shows the output power ratio before and after coloring.

This result shows that there is a linear correlation on a logarithmic scale between the concentration of the inosine aqueous solution and the output power ratio before and after coloring. Note that the measurement time required for this was about 5 minutes.

Comparative Example When inosine was quantified by liquid chromatography or colorimetric method using enzymes, it took 3 hours and 4 hours, respectively.
A measurement time of 0 minutes was required.

Example 2 A 500 mm thick O1 film and a 100 mm thick Pd film were applied to the cladding material removed portion of the optical fiber used in Example 1.
The membranes were sequentially steamed to produce a fiber-shaped hydrogen gas sensor. Hydrogen-containing air having hydrogen concentrations ranging from 20 to 1000 pp+i was blown thereon, and measurements using the evaluation apparatus shown in FIG. 2 were carried out in the same manner as in Example 1.

In this case, hydrogen oxidized by Pd is reacted with wOl, and the degree of coloration of the wOl is measured.

The obtained results are shown in the graph of FIG. 4, and it can be seen from the results that there is a linear correlation on a logarithmic scale between the hydrogen concentration and the output power ratio before and after spraying. Note that the measurement time required for this was about 2 minutes.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(C) respectively show one embodiment of a fiber-like sensor according to the present invention as a front view and a sectional view taken along the line I-I. FIG. 2 is a schematic diagram of the fiber sensor evaluation apparatus of the present invention. Moreover, FIGS. 3 and 4 are graphs showing the measurement results of Examples 1 and 2, respectively. (Explanation of symbols) 1... Clad material 2... Core material 3... Optical fiber 4... Color-forming substance 5... Fiber-like sensor 6... ... Source medium 7 ... Light emitting element 8 ... Light receiving element

Claims (1)

[Claims] 1. A fiber-like sensor in which a part of the cladding portion of a step-index multimode optical fiber is replaced with a substance that reacts with a substance to be detected and exhibits a color change. 2. At both ends of the fiber-like sensor according to claim 1,
An evaluation device for a fiber-like sensor, in which a light-emitting element and a light-receiving element are respectively installed via an optical medium.