JPH0816662B2 - Preservation liquid storage tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a storage solution storage tank, and more particularly to a storage solution storage tank for storing a storage solution for maintaining the activity of an enzyme electrode.

<Prior Art and Problems to be Solved by the Invention> Focusing on the characteristic that an extremely complicated organic compound, protein or the like can be detected with extremely high sensitivity and selectivity, A biosensor having an immobilized enzyme membrane with a physiologically active substance immobilized on its surface (hereinafter,
Research and development for measuring the above-mentioned organic compounds, proteins and the like by means of an enzyme electrode).

When the measurement target substance is measured using the enzyme electrode, an oxidation reaction or a reduction reaction of the measurement target substance is carried out in the presence of a physiologically active substance, and the reaction product is produced or disappears. An electric signal corresponding to the amount of the substance to be measured is output from the enzyme electrode, and the electric signal is subjected to necessary processing to obtain the concentration of the substance to be measured. Furthermore, since the above oxidation reaction or reduction reaction is actively carried out only in the presence of an active physiologically active substance, after the concentration measurement is completed,
The surface of the enzyme electrode must be kept in contact with the preservative solution so that the physiologically active substance is not deactivated until the next concentration measurement.

Therefore, conventionally, the enzyme electrode is immersed in the storage solution contained in the container after the measurement. However, when such a configuration is adopted, it is necessary to make the enzyme electrode large enough so that the extraction lead or the like is not immersed because the enzyme electrode having the extraction lead or the like is immersed in the storage solution. At the same time, the container containing the preservative solution also has to be quite large, and the overall configuration is significantly large, which makes it inconvenient to make the size extremely portable.

The applicant of the present patent application is to eliminate such inconvenience.
An arrangement was considered in which an opening was formed at a predetermined position of a remarkably small stock solution storage tank, a sponge was attached to this opening, and the surface of the enzyme electrode was pressed against the sponge after the measurement was completed.
If this configuration is adopted, not only the size of the storage solution storage tank can be significantly reduced, but also the enzyme electrode can be significantly reduced, and the concentration measuring device can be miniaturized as a whole. Since the intended purpose can be achieved only by pressing the sponge onto the sponge, the structure can be simplified.

However, when a concentration measuring device incorporating this structure was prepared and the concentration of the substance to be measured in the test liquid was measured, the measured values showed a large variation and the CV value was about 10%.

<Objects of the Invention> The present invention has been made in view of the above problems, and can be miniaturized as a whole, and can store a preservative solution that can constantly maintain good activity of a physiologically active substance on the surface of an enzyme electrode. Intended to provide a tank.

<Means for Solving the Problems> In order to achieve the above-mentioned object, a storage solution storage tank of the present invention has a storage solution storage tank for storing a storage solution for maintaining the activity of an enzyme electrode, which is a predetermined storage tank. It is composed of a tank main body with an opening formed at a position and a porous body arranged so as to be positioned at the opening, and communicates with the outside at the contact portion between the vicinity of the opening of the tank main body and the porous body. A groove is formed.

<Operation> In the case of the storage liquid storage tank having the above configuration, the storage liquid is slightly lost by pressing the enzyme electrode against the porous body after the concentration measurement is completed, and the internal pressure of the storage liquid storage tank is slightly lower than the external pressure. However, when the enzyme electrode is separated from the porous body, the inside and the outside of the storage solution storage tank communicate with each other through the communication groove, so that the internal pressure and the external pressure can be quickly balanced. As a result, the surface of the porous body can always be maintained in a wet state, and the activity of the physiologically active substance can be favorably maintained every time the enzyme electrode is pressed against the porous body.

More specifically, in the case where the communicating groove is not formed, even if a porous body having a large porosity and a large pore size is used, the whole porous body is impregnated with the preservative solution. , Even if a pressure difference between the internal pressure and the external pressure of the storage liquid storage tank occurs, it is equivalent to being sealed, and air is stored to eliminate the pressure difference until the pressure difference exceeds a predetermined pressure. It was blocking entry into the liquid storage tank. Therefore, the wet state of the surface of the porous body changes significantly under the influence of the number of times the enzyme electrode is pressed, the temperature difference between the inside and outside, the difference between the inside pressure and the outside pressure, and the supply of the preservation solution when the enzyme electrode is pressed against the porous body. Since the degree of activity maintenance of the physiologically active substance changes greatly, the dispersion of the measured values was extremely large and the CV value was about 10%. However, in the present invention, since the communication hole is formed at a predetermined position of the tank body that is in contact with the porous body, there is no inconvenience that the differential pressure between the inside and the outside increases to the predetermined pressure, and the surface of the porous body is The differential pressure is relieved before the wet state changes substantially.
As a result, the degree of supply of the preservation solution and the maintenance of the activity of the physiologically active substance when the enzyme electrode is pressed against the porous body can be kept constant, and the dispersion of measured values can be significantly reduced.

<Example> Hereinafter, an example will be described in detail with reference to the accompanying drawings.

FIG. 5 is a partially cutaway perspective view showing an example of the configuration of a concentration measuring device incorporating the preservation liquid storage tank of the present invention,
An enzyme electrode (2) reciprocated by an electrode driving mechanism (3) is provided at a predetermined position of the concentration measuring device main body (1), and a storage solution storage tank (4) is detachably provided at the predetermined position. Has been. Then, the test solution permeation holes (5a) are formed in the central portion at predetermined intervals, and
A function to prevent the permeation of substances with a large particle size so as to cover each test solution permeation hole (5a), a function to limit the diffusion to some extent, a function to deposit the test solution without touching the enzyme electrode, etc. A long film (5) having a diffusion limiting film (5b) attached thereto is accommodated in a casing (5c) so that it can travel, and this casing (5c) is at a predetermined position of the concentration measuring device main body (1). It is provided to be removable.
The diffusion limiting film (5b) can prevent clogging of the diffusion limiting film when the diffusion limiting film is attached to the enzyme electrode (2) as will be described later, and the enzyme electrode ( The diffusion to 2) can be limited to some extent. On the contrary, when the diffusion limiting membrane is not attached to the enzyme electrode (2),
It is possible to limit the diffusion of the substance to be measured into the enzyme electrode (2).

The enzyme electrode (2) is one in which a selective permeation membrane for selectively permeating a reaction product or a reaction disappearing substance and an immobilized enzyme membrane are mounted in this order on the surface of a base electrode, and as necessary. A diffusion limiting membrane having a high diffusion limiting effect on the substance to be measured is attached to the surface side of the immobilized enzyme membrane.
An enclosing member (2a) that encloses at least the upper part of the enzyme electrode (2) is provided.

The electrode drive mechanism (3) is a mechanism having components such as a motor (3a), a screw shaft (3b), an electrode support plate (3c), an engaging protrusion (3d) and a guide groove (3e), Motor (3a)
Causes the screw shaft (3b) to rotate, thereby operating the electrode support plate (3c), and further, the engaging projection (3d) and the guide groove (3
The operation of the electrode support plate (3c) is restricted by engagement with e), and the enzyme electrode (2) supported by the electrode support plate (3c) is
It is reciprocated between a position in contact with the storage liquid storage tank (4) and a position in contact with the diffusion limiting film (5b) of the long film (5).

The preservation liquid storage tank (4) is a thin tank body (4
An opening (4b) is formed at a predetermined position on the lower surface of (a), and a sponge (4c) is provided so as to enter the opening (4b). Then, a plurality of communication grooves (4d) are formed in the tank body (4a) at positions contacting the sponge (4c).

The preservation liquid storage tank will be described in more detail with reference to FIGS. 1 to 4.

The periphery of the opening (4b) formed in the tank body (4a) is
It is extended outward as it is, and the thread (4e) is formed on the outer surface of the outward extension, so the cap (4f) for preventing leakage of the preservation solution is detachably attached. . The cap (4f) must be removed when the storage solution storage tank (4) is attached to the concentration measuring device body (1). Note that (4g) is a ridge that prevents leakage of the storage solution that comes into contact with the inner surface of the cap (4f). In addition, an inward flange (4h) is formed at the tip of the outward extension, and an inward flange to prevent the sponge (4c) from slipping out slightly inward of the inward flange (4h). (4j) is formed, and a seal that prevents the preservation liquid from leaking to the outside when the enzyme electrode (2) is pressed into contact with the surrounding member (2a) in the gap between the inward flanges (4h) and (4j).・ Packing (4k) is provided. Therefore, a plurality of communication grooves (4d) having a U-shaped cross section are formed on the upper surface of the inward flange (4j) and the inner surface of the outer extension portion on the inner side of the inward flange (4j).

The casing (5c) includes a supply unit (5d) that accommodates one end side of the long film (5) in a wound state, and a winding unit that winds the other end side of the long film (5). Department (5e)
And a bridge part (5f) that connects the supply part (5d) and the winding part (5e), and further allows the enzyme electrode (2) to enter the predetermined position on the lower surface of the bridge part (5f). A through hole (not shown) is formed. Then, the power from the long film feeding mechanism (not shown) is transmitted to the winding shaft (not shown) housed in the winding portion (5e).

The operation of the concentration measuring device having the above configuration is as follows.

Electrode drive mechanism (3) when concentration measurement is not performed
The enzyme electrode (2) is pressed against the sponge (4c) through the opening (4b) of the storage solution storage tank (4) by the (6th).
See FIG. In this state, the surrounding member (2a)
Since the seal and packing (4k) are pressed against each other,
It is possible to reliably prevent the inconvenience that the storage solution leaks to the outside.

If the test liquid is spotted on the unused test liquid permeation hole (5a) of the long film (5) and a measurement start switch (not shown) is operated, the long film (5) runs for a predetermined distance, Further, the enzyme electrode (2) is moved by the electrode driving mechanism (3) and pressed against the diffusion limiting film (5b). Therefore, the substance to be measured in the test liquid diffuses through the diffusion limiting membrane (5b) to the surface of the enzyme electrode (2), and an oxidation reaction or a reduction reaction is performed in the presence of an active physiologically active substance. The substance or the reaction disappearing substance is guided to the base electrode through the selective permeable membrane, and an electric signal corresponding to the amount of the reaction product substance or the reaction disappearing substance is output. Then, the concentration of the substance to be measured in the test liquid can be obtained based on the peak of the electric signal, the peak of the signal obtained by differentiating the electric signal over time, and the like.

After the concentration measurement is performed as described above, the electrode driving mechanism (3) moves the enzyme electrode (2) in the opposite direction, and again presses the sponge (4c) of the preservation solution storage tank (4). Maintain the activity of physiologically active substances. In addition, in parallel with this operation, the long film (5) is run for a predetermined distance,
The next test solution permeation hole is located at the spotting position.

Hereinafter, the series of operations described above is repeated every time concentration measurement is instructed.

If the above operation is repeated, the preservative solution in the preservative solution storage tank (4) is gradually supplied to the enzyme electrode (2), so that the preservative solution in the interior decreases and a differential pressure between the inside and outside occurs. However, since the inside and the outside are communicated by the communication groove (4c), air enters from the outside with a slight differential pressure (see the arrow in FIG. 6 (B)) to eliminate the differential pressure. be able to. As a result, the storage solution is sufficiently transferred to the surface of the sponge (4c), and the enzyme electrode (2) can be sufficiently wetted. As a result, the variation of the measurement, which was CV = 10% in the past, can be made CV = 2 to 3%.

However, the number, width, depth, etc. of the communication grooves (4d) may be set as appropriate in consideration of the fluid resistance of air, and the inner end of the plurality of communication grooves (4d) may be located at one place. It is also possible to collectively introduce air into a desired location of the storage solution storage tank (4). Furthermore, it is possible to use a porous body other than a sponge.

Further, in the above embodiments, the communication groove (4d) is formed in the tank body (4a), but the communication groove may be formed in the sponge (4b). However, considering the workability and the fact that the width and depth of the communication groove (4d) can be made constant, it is preferable to form the communication groove (4d) in the tank body (4a).

<Effects of the Invention> As described above, according to the present invention, the communication groove is formed in the contact portion between the porous body and the vicinity of the opening of the tank body, so that the pressure difference between the inside and the outside is not significantly increased. External air can be introduced into the liquid storage tank, the surface of the porous body can be kept in a wet state at all times, and the activity of the enzyme electrode can be effectively maintained.

[Brief description of drawings]

FIG. 1 (A) is a perspective view showing only the opening of the storage solution storage tank, FIG. 1 (B) is a plan view of the same, FIG. 2 is a bottom view of the storage solution storage tank, and FIG. 3 is a longitudinal sectional view of the same. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1, and FIG. 5 is a partially cutaway perspective view showing an example of the configuration of a concentration measuring device incorporating the preservation liquid storage tank of the present invention, and FIG. ) Is a vertical cross-sectional view showing a state where the enzyme electrode is pressed against the sponge, and FIG. 6B is a schematic view illustrating an air flow for eliminating the pressure difference between the inside and the outside. (2) …… Enzyme electrode, (4) …… Preservation liquid storage tank, (4a) …… Tank body, (4b) …… Opening, (4c) …… Sponge as porous body, (4d) …… Communication groove

Claims (1)

[Claims] 1. A tank body (4a) having a storage solution storage tank (4) for storing a storage solution for maintaining the activity of an enzyme electrode (2), the tank body (4a) having an opening (4b) formed at a predetermined position, It is composed of a porous body (4c) arranged so as to be located in the opening (4b), and a contact portion between the vicinity of the opening (4b) of the tank body (4a) and the porous body (4c). A storage solution storage tank, characterized in that a communication groove (4d) with the outside is formed in the.