JPH0765978B2 - Trace component measuring method and trace component measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a trace amount component and a device for measuring a trace amount component, and more specifically, it provides simple and continuous measurement with little variation in measurement results due to measurement conditions such as temperature. A method for measuring trace components,
The present invention also relates to a light weight, small size, and convenient handling trace amount component measuring device that can be suitably used for the method.

[0002]

2. Description of the Related Art In recent years, in the field of bioelectronics, development of biosensors including enzyme sensors, microbial sensors, etc. for measuring a specific substance by utilizing an enzymatic reaction has been actively pursued. is there. Furthermore, development of analytical instruments, measuring instruments, medical instruments, etc. equipped with biosensors has been actively conducted. Among these, one of the notable ones is a blood glucose measuring device that measures the glucose concentration in blood. Blood glucose level is an important factor that must be controlled for diabetics. Conventionally, for example, the following blood glucose measuring device has been proposed.

First, a physiological saline solution is first sent to a hollow fiber for dialysis, which is placed in a solution to be measured, such as a biological fluid, using a syringe pump. Next, in the dialysis hollow fiber, glucose contained in the liquid to be measured is dialyzed by utilizing the difference in concentration between the inside and the outside. Then, this dialysate is sent to the measuring unit, and the amount of glucose in the dialysate is measured by the glucose sensor in the measuring unit (Hashiguchi et al., Artificial Organ 21 (3); 1094 (1992), Hashiguchi et al.
Medical Electronics and Biotechnology, Vol. 30, Special Issue (1992)).

In other cases, first, a physiological saline solution and glucose oxidase are sent to a hollow fiber for dialysis, which is left in a solution to be measured such as a biological fluid by using a syringe pump or a peristaltic pump. Next, in the dialysis hollow fiber, the glucose contained in the liquid to be measured is dialyzed by utilizing the difference in concentration between the inside and outside thereof, and the glucose and glucose oxidase are reacted. Then, the amount of oxygen consumed during the reaction is an apparatus for indirectly measuring the glucose concentration by measuring the glucose concentration by measuring with an oxygen sensor in the measuring unit (AJM Schoonen et al., Biosensors and Bioelec
tronics 5; 37 (1990), AL Aalders et al., Intern.
J. Artif. Organs; 14 (2); 102 (1991)). Also,
In addition to the glucose concentration, an apparatus has been proposed in which the concentration of the drug in the dialysate obtained in the same manner is measured by a mass spectrometer (see RMCaprioli, WO9014791).

However, in these devices, a mechanically driven syringe pump or the like is used to send physiological saline for dialysis of trace components in the liquid to be measured to the dialysis hollow fiber. However, there is a problem that the entire device is large and heavy, inconvenient to handle, and expensive.

By the way, since the enzyme has an optimum temperature at which its reaction activity is maximized, the enzyme reaction has temperature dependence. Therefore, when using a biosensor that utilizes an enzymatic reaction, it is generally necessary to use it under a constant temperature condition or to have a temperature compensation mechanism itself.

However, none of the above conventional devices is provided with a temperature compensation mechanism. Moreover, since the use conditions are often in an environment where the temperature is not always controlled to a constant temperature, there is a problem that the influence of temperature is directly exerted and a measurement error is large. It is very dangerous for a patient to perform treatment / treatment such as insulin administration based on a measurement result having such a large error, for example, a blood glucose level.

With the rapid increase in adult diseases such as diabetes and the aging of society, trace components such as blood glucose can be measured continuously and safely and accurately with little influence of measurement conditions. There is a particular need in the medical field for a compact and convenient device to handle. The present invention solves the above-mentioned problems, and in response to such a demand, by reducing the output fluctuation due to temperature dependence and the like, it is possible to measure trace components simply and continuously, and with a small measurement error and high accuracy. An object of the present invention is to provide a method for measuring a trace component and a device for measuring a trace component, which is suitable for the method and is small in size and convenient to handle.

[0009]

In order to solve the above-mentioned problems, the present inventor has made earnest studies and found that the conventional measuring device is driven by the osmotic pressure of the solution instead of the mechanically driven syringe pump. It has been found that the use of the infusion pump of the type makes it possible to reduce the size of the entire apparatus and improve the handleability. Even more surprisingly, the temperature dependence of the dialysis glucose concentration and the glucose sensor output by the osmotic pressure driven infusion pump are opposite to each other, and the temperature dependences of the two are counteracted and offset, resulting in The inventors have found that the temperature dependence of the entire device can be reduced and have reached the present invention.

That is, claim 1 for solving the above problems
In the invention described in 1), the perfusate is discharged by an infusion pump using the osmotic pressure of the solution as a driving source, the discharged perfusate is stored in a dialysis probe, and a trace component to be measured is further dialyzed in the perfusate. It is a trace component-containing perfusate that is taken in by and is sent out, and a trace component measuring method characterized by measuring a trace component contained in the delivered perfusate with an enzyme sensor flow cell,
The invention according to claim 2 is the method for measuring a trace component according to claim 1, wherein the trace component is glucose, and the invention according to claim 3 uses the osmotic pressure of the solution as a driving source. An infusion pump that discharges the perfusion solution, a dialysis probe that contains the discharged perfusion solution and takes in the trace component to be measured by dialysis to form a trace component-containing perfusion solution, and a dialysis probe that sends this out. An enzyme sensor flow cell for measuring a trace component contained therein, the trace component measuring device according to claim 4, wherein the trace component is glucose. It is a device.

[0011]

In the method for measuring trace constituents of the present invention, the perfusate is discharged by the injection pump using the osmotic pressure of the solution as the driving source. The discharged perfusate is stored in the dialysis probe. Next, in the dialysis probe, the trace components to be measured are incorporated into the perfusion solution by dialysis. Then, a perfusate containing trace components is generated inside the dialysis probe. It is then sent to the enzyme sensor flow cell. In the enzyme sensor flow cell, trace components contained in the sent perfusate are measured.

Further, in the trace component measuring apparatus of the present invention, the infusion pump discharges the perfusate using the osmotic pressure of the solution as a driving source. The dialysis probe accommodates the perfusate and takes in trace components to be measured into the perfusate by dialysis. Then, in the dialysis probe, a perfusate containing trace components is generated. Further, the dialysis probe delivers the perfusate containing the trace components. The perfusate containing trace components is subjected to an enzymatic reaction in an enzyme sensor flow cell.
With this, a trace component is measured. Since the injection pump is an osmotic pressure drive system, this trace component measuring device does not require a drive member such as a motor or a power source, so that the entire device is extremely small and convenient to handle.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Below, a description will be given of a trace component measuring apparatus and a trace component measuring device of the present invention with reference to the drawings.
The present invention is not limited to the following embodiments. FIG. 1 is a schematic explanatory view showing one embodiment of the trace component measuring apparatus of the present invention. The trace component measuring device shown in FIG. 1 includes an infusion pump 1 and a dialysis probe 20.
And an enzyme sensor flow cell 30.

The infusion pump 1 and the dialysis probe 20
Are connected to each other by a vinyl chloride tube 40a. The dialysis probe 20 and the enzyme sensor flow cell 30 are connected by a vinyl chloride tube 40b. The infusion pump 1 discharges the perfusate and injects it into the dialysis probe. The infusion pump 1 has a water filling container 13, an osmotic pressure container 7, and a perfusate supply container 3. The water filling container 13 and the osmotic pressure container 7 are the water outflow pipe 6b.
Further, the osmotic pressure container 7 and the perfusate supply container 3 are connected by the aqueous solution outflow pipe 6a.

The water filling container 13 has a water filling chamber 1 inside.
With 2b. The osmotic pressure container 7 includes a support 9 having a water passage hole 8 therein and a flat membrane-shaped semipermeable membrane 1 stretched over the support 9.
Equipped with 0. Further, it has an aqueous solution chamber 11b facing the aqueous solution outflow pipe 6a and a water filling chamber 12a facing the water outflow pipe 6b, which are defined by the support 9 and the semipermeable membrane 10.

The perfusate supply container 3 has a moving member 4 which is in close contact with the inner wall of the perfusion liquid supply container 3 and can slide back and forth, and a spout 2 in the perfusion liquid supply container 3.
Rubber stopper 14 fixed by closing the opening on the side opposite to
With. Further, it has a perfusion solution chamber 5 defined by the spout 2 and the mover 4, and an aqueous solution chamber 11 a defined by the mover 4 and the rubber plug 14.

Water filling chamber 12 in the water filling container 13
b accommodates water therein. The water filling chamber 12a of the osmotic pressure container 7 stores water inside, and the aqueous solution chamber 11b stores an aqueous solution for inducing osmotic pressure inside. Aqueous solution chamber 11a in the perfusion solution supply container 3
Contains the aqueous solution 11 therein, and the perfusion solution chamber 5
Contains a perfusion solution 5a which is physiological saline.

In this injection pump 1, in the osmotic pressure vessel 7, the water contained in the water filling chamber 12a moves to the aqueous solution chamber 11b by the osmotic pressure. Then, the volume of the aqueous solution 11 in the aqueous solution chamber 11b increases. Then,
Aqueous solution 1 that cannot be stored in the aqueous solution chamber 11b
1 is pushed out to the aqueous solution chamber 11a in the perfusion solution supply container 3 through the aqueous solution outflow pipe 6a. Then, the volume of the aqueous solution 11 in the aqueous solution chamber 11a increases, and the mover 4 is pushed to the spout 2 side. As a result, the perfusate 5 a that cannot be stored in the perfusate chamber 5 is discharged from the spout 2. The discharged perfusate 5a passes through the inside of the tube 40a and is injected into the dialysis probe 20. In this manner, the infusion pump 1 discharges the perfusate 5 a and injects it into the dialysis probe 20.

The dialysis probe 20 accommodates the perfusate 5a discharged from the infusion pump 1, takes in the trace component to be measured into the perfusate 5a by dialysis, and forms the trace component-containing perfusate 5b. Send to the enzyme sensor flow cell 30. The trace component measured in this example is glucose contained in blood. The dialysis probe 20 includes an inlet 23, a needle shaft 21, a dialysis membrane 22, an outlet 24, and a reinforcing material 25. The dialysis probe 20 has a needle-like shape.

The inlet 23 is a hollow fine hole, and one end thereof is connected to the tube 40a. The inlet 23 is housed inside the hollow needle shaft 21. There is a space between the inlet 23 and the needle shaft 21 inside the needle shaft 21. This space is the outlet 24. The outlet 24 and the enzyme sensor flow cell 30 are connected by a tube 40b.

The tip of the dialysis probe 20, that is, the tip of the needle shaft 21 is a dialysis membrane 22. On the other hand, the branching portion of the inlet 23 and the outlet 24 on the opposite side is fixed by the reinforcing material 25. The dialysis membrane 22 is a hollow fiber, which is a hollow fiber dialysis membrane. The length of the dialysis membrane 22 is 15 mm.

In the dialysis probe 20, the dialysis membrane 22
Other than is a closed system, there is no transfer of substances to or from the outside. The dialysis probe 20 is left in the blood to be measured containing glucose. In the dialysis probe 20, the perfusate 5a discharged from the infusion pump 1 is guided to the inlet 23 via the tube 40a. Further, the perfusate 5a is guided to the dialysis membrane 22 through the inlet 23. In the dialysis membrane 22, due to the difference in concentration between the perfusate 5a, which is physiological saline inside the dialysis membrane 22, and the blood, which contains glucose outside, in the dialysis membrane 22, glucose is adsorbed on the dialysis membrane 2
It passes through 2 and moves into the dialysis probe 20, and is taken in. As a result, glucose is dialyzed. Then, the perfusate 5a becomes the glucose-containing perfusate 5b, passes through the outlet 24, and passes through the tube 40b.
And is sent to the enzyme sensor flow cell 30.

The enzyme sensor flow cell 30 measures the trace components contained therein while passing the trace component-containing perfusion liquid 5b sent from the dialysis probe 20 through the tube 40b. The enzyme sensor flow cell 30 is
It is composed of an enzyme sensor 31 and a flow cell 32. The enzyme sensor 31 is a glucose sensor. The enzyme sensor 31 measures the glucose to be measured,
It has an enzyme film 33 on which glucose oxidase, which is an enzyme that catalyzes the oxidation reaction of glucose, is immobilized. An enzymatic reaction is performed in this enzyme film 33.

The principle of measuring glucose is as follows: In the following oxidation reaction of glucose catalyzed by glucose oxidase, glucose + O ₂ → gluconolactone + H ₂ O ₂ generated hydrogen peroxide is used as a working electrode by a current method. By detecting by.

The flow cell 32 is designed so that the perfusate 5b containing a trace component can pass while contacting the enzyme membrane 33 of the enzyme sensor 31. The trace component-containing perfusion liquid 5b that has passed through the enzyme sensor flow cell 30 is guided to a waste liquid bottle by a tube 40c and disposed of as a waste liquid. In the enzyme sensor flow cell 30, the trace component-containing perfusion solution 5b sent from the dialysis probe 20 via the tube 40b is introduced into the enzyme sensor flow cell 30. Perfusion solution containing trace components 5b
Passes through the inside of the enzyme sensor flow cell 30 while being in contact with the enzyme film 33 of the enzyme sensor 31. At this time, the oxidation reaction by glucose oxidase is performed in the enzyme film 33. Hydrogen peroxide generated by this enzymatic reaction is subjected to a redox reaction at a platinum electrode (not shown) in the enzyme sensor 31. Then, a limiting diffusion current is obtained by the redox reaction.
This current is guided by a lead wire 34 to a measuring device (not shown) and is measured. The measurement result is converted into glucose concentration by a calibration line created in advance. In this way, the amount of glucose can be measured.

<< Characteristics of Trace Component Measuring Device >> The following characteristics of the trace component measuring device in this example were tested. <Relationship Between Discharge Amount of Injection Pump and Temperature> FIG. 4 shows the relationship between the discharge amount of the injection pump and temperature. Here, in the injection pump, the pump shown in FIG. 1 in which a flat membrane of cellulose acetate was used as the semipermeable membrane 10 and a saturated aqueous solution of sodium chloride was used as the aqueous solution 11 was used. As can be seen from the graph of FIG. 4, the infusion pump used in the present invention is
Compared with the conventional syringe pump, the change rate of the discharge amount with respect to the temperature change is much larger. That is, the infusion pump used in the present invention has a greater temperature dependency than the conventional syringe pump. The temperature dependence of the discharge amount in the injection pump is usually +3 to 6 (% / ° C). In this case, the temperature dependence of the discharge amount in the injection pump is +5.3 (% / ° C.) based on 25 ° C., while
The temperature dependence of the discharge amount in a conventional syringe pump is 0
(% / ° C.).

<Relationship between the concentration of glucose dialyzed by the dialysis probe and the temperature> The dialysis probe (caprophan membrane hollow fiber, membrane length 15 mm) in the trace component measuring apparatus of the present invention has a glucose concentration of 100 (m).
g / dl physiological saline), and the concentration of glucose dialyzed by the dialysis probe is GO.
It was measured by the D colorimetric method, and the temperature dependence of the dialysis efficiency of glucose was examined. At this time, an infusion pump having the characteristics shown in FIG. 4 was used, and a physiological saline solution was used as the perfusate to be discharged.

As a result, as shown in FIG. 5, it was found that the temperature dependence of the infusion pump according to the present invention was large, and the higher the temperature, the lower the dialysis efficiency corresponding to the increase in the discharge amount. . The temperature dependence of the dialysis glucose concentration in the infusion pump at 25 ° C. is −
2.5 (% / ° C.), while the temperature dependence of the dialysis glucose concentration in the conventional syringe pump is +0.2.
(% / ° C.).

<Relationship between the output of the enzyme sensor and the temperature> In order to investigate the temperature dependence of the output of the enzyme sensor,
Using a syringe pump, the glucose concentration is 100 (m
An aqueous solution (g / dl physiological saline) was sent to the enzyme sensor flow cell at a discharge rate of 100 (μl / hr).
For the enzyme sensor, the anode is platinum and the cathode is silver /
A glucose sensor prepared by immobilizing glucose oxidase on a hydrogen peroxide electrode of silver chloride was used. The output current of the enzyme sensor in the enzyme sensor flow cell was measured with a potentiostat (applied voltage 0.
65 V), the temperature dependence of the enzyme sensor output was investigated. As a result, the relationship between the enzyme sensor output and the temperature was obtained as shown in FIG. The temperature dependence of the enzyme sensor output was +3.2 (% / ° C) based on 25 ° C.

<Temperature Dependence of Trace Component Measuring Device According to the Present Invention> The trace component measuring device of the present invention, that is, a trace component measuring device comprising an infusion pump, a dialysis probe and an enzyme sensor flow cell, and a conventional device, that is, The temperature dependency with a measuring device consisting of a syringe pump, a dialysis probe and an enzyme sensor was investigated. As the infusion pump, the dialysis probe and the enzyme sensor, those having the characteristics shown in FIGS. In addition, as the perfusate,
Using physiological saline, the dialysis probe was immersed in an aqueous solution having a glucose concentration of 100 (mg / dl physiological saline), and the output current of the enzyme sensor was measured with a potentiostat.

As a result, as shown in FIG. 7, the change rate of the enzyme sensor output with respect to the temperature change is smaller in the trace component measuring device according to the present invention than in the conventional measuring device. That is, the temperature dependence was small. The temperature dependency of the trace component measuring device according to the present invention is +0.6 (% / ° C.) based on 25 ° C., while the temperature dependency of the conventional measuring device is +3.3 (% / ° C.). ℃).

The reason for the above results is that in the trace component measuring device according to the present invention, the temperature dependence of the dialysis glucose concentration by the infusion pump and the output of the enzyme sensor are opposite to each other. The respective temperature dependences were canceled out, and as a result, the temperature dependence could be reduced. The trace component measuring apparatus according to the present invention can reduce the influence of temperature when measuring trace components.

As another embodiment of the present invention, instead of the infusion pump 1, the dialysis probe 20 or the enzyme sensor flow cell 30 in the above-mentioned embodiment, the following infusion pump, dialysis probe or enzyme sensor flow cell is used to measure a trace amount of components. A device can be mentioned. The trace component measured in the above examples was glucose, but in the present invention, there is no particular limitation as long as it is a substance that can be dialyzed with a dialysis probe and can be measured by an enzymatic reaction. For example, neurotransmitters such as acetylcholine, amines, amino acids, aldehydes, uric acid,
In-vivo components such as lactic acid, pyruvic acid, cholesterol, and glucose can be mentioned.

The tube connecting the dialysis probe and the infusion pump or the dialysis probe and the enzyme sensor flow cell is a coil when the dialysis probe 20 is left in a living body such as a human being or an animal. It is preferably in the form of a shape. This is because the coiled shape prevents the dialysis probe 20 from coming off even if the animal or the like moves. In the present invention, instead of the infusion pump 1 in the above-described embodiment, for example, the infusion pump 1 having the osmotic pressure vessel having the hollow fiber semipermeable membrane shown in FIG. 2 can be used.

The infusion pump 1 shown in FIG. 2 has the same function as the infusion pump 1, but the structure of the osmotic pressure vessel 7 is different. The osmotic pressure container 7 includes a partition member 16 and a hollow fiber-shaped semipermeable membrane 10. Also, the partition member 1
It has a water filling chamber 12a and an aqueous solution chamber 11b defined by 6 and the hollow fiber-shaped semipermeable membrane 10. The length and the number of the hollow fiber-shaped semipermeable membranes 10 are not particularly limited and can be appropriately selected according to the purpose.

In this osmotic pressure vessel 7, the semipermeable membrane 10
Because of the large surface area, the water transfer efficiency is high. Therefore, the infusion pump 1 having the osmotic pressure container 7 is suitable for discharging the perfusate at an appropriately large speed. In addition, as shown in FIG. 3, an infusion pump having a perfusion solution supply container 3 having a perfusion solution chamber 5 formed by a volume-variable envelope having the opening as a spout 2 can be mentioned.
The envelope is not particularly limited as long as it has a variable volume and can store a solution therein, and examples thereof include an envelope formed of rubber or vinyl.

In this injection pump 1, when the water contained in the water filling chamber 12a of the osmotic pressure vessel 7 moves to the aqueous solution chamber 11b by the osmotic pressure, the volume of the aqueous solution 11 in the aqueous solution chamber 11b increases. Then, the aqueous solution chamber 11
The aqueous solution 11 that cannot be accommodated in a is pushed out to the aqueous solution chamber 11a in the perfusion solution supply container 3 through the aqueous solution outflow pipe 6a. At this time, the aqueous solution 11 presses the wall surface of the envelope forming the perfusion solution chamber 5. Then, the volume of the perfusate chamber 5 is reduced, and the perfusate 5a that cannot be accommodated inside is discharged from the spout 2. The discharged perfusion solution 5a is sent to the dialysis probe by a tube connected to the spout 2. Thus, the perfusate can be injected into the dialysis probe.

Further, as other examples of the injection pump 1, Japanese Patent Laid-Open Nos. 1-126979, 1-223974, 3-52524, 3-58437 and 4-37.
The pumps described in each publication of No. 22963 can be mentioned. The volume of the perfusate chamber in these infusion pumps 1 is usually 2 to 50 ml. The aqueous solution with which the aqueous solution chamber 11b is filled is not particularly limited as long as it is a solution in which a solute causing an osmotic pressure is dissolved in a saturated state. As the solute, for example, water-soluble inorganic salts such as sodium chloride and potassium chloride, water-soluble organic acid salts such as sodium citrate and sodium benzoate, and water-soluble polymer substances such as polyethylene glycol can be used.

In the present invention, the solute is further replenished in the aqueous solution chamber in a solid state such as granules or tablets for the purpose of preventing the osmotic pressure difference from being reduced due to the aqueous solution being diluted by the moving water. You can also The perfusate can be appropriately selected according to the purpose. For example, when a trace component in blood is to be measured, physiological saline that is isotonic with blood is usually used. The physiological saline may be prepared or commercially available.

The discharge amount of the injection pump is usually 50 to 400.
μl / hr. The discharge speed of the injection pump can be adjusted by changing the diameter of the spout, the amount or concentration of the aqueous solution to be filled in the aqueous solution chamber, the surface area of the semipermeable membrane, etc. so as to suit the purpose. The infusion pump 1 in the present invention may be any pump as long as it can discharge the perfusate without generating a pulsating flow due to the osmotic pressure of the solution, and its size, shape, and structure are not particularly limited, It can be selected as appropriate. The infusion pump may be provided at any position in the trace component measuring device. The number of infusion pumps used may be one, or two or more.

In the present invention, instead of the dialysis probe 20 in the above-described embodiment, for example, a linear dialysis probe in which one end of a hollow fiber having open both ends is connected to the inlet and the other end is connected to the outlet. Can be used. In this case, since the dialysis probe has a straight and simple shape, the flow of the perfusate is smooth. Each part in these dialysis probes can be variously selected.

The inlet, outlet, and needle-shaped shaft are usually linear shapes made of appropriately selected materials in consideration of the generation of retention of the perfusate flowing inside the shaft. The dialysis membrane is usually hollow fiber which is a hollow fiber dialysis membrane. Examples of hollow fibers include caprophane and ethylene vinyl alcohol copolymer (E
VAL) and the like, but in the present invention, it can be appropriately selected according to the purpose.

The length of the dialysis membrane is usually 1 to 30 mm. This length can be appropriately selected depending on the measurement target. The outer diameter of the dialysis membrane is usually 200 to 300 μm. The thickness of the dialysis membrane is usually 5 to 50 μm.
The outer diameter of the dialysis membrane portion of the dialysis probe is usually 200 to 30.
It is 0 μm. The trace components that can be incorporated by this dialysis probe have a molecular weight of about 20000 to 600.
It is a relatively low molecular weight trace component of 00 or less.

Therefore, since proteins such as albumin are rarely dialyzed, there is no need to perform deproteinization or the like when measuring trace components in the enzyme sensor flow cell, and the measurement operation is simple and , High accuracy because there is little loss of trace components to be measured. Further, since the enzyme sensor flow cell is not contaminated with protein or the like, deterioration of the enzyme sensor can be extremely reduced.

As the dialysis probe in the present invention,
As long as it has a function of containing the perfusate discharged from the infusion pump and incorporating the trace component to be measured into the perfusate by dialysis to form the trace component-containing perfusate, and sending it to the enzyme sensor flow cell. There are no particular restrictions,
A commercially available product can also be used. The size, shape, and structure are not particularly limited, but needle-shaped ones can be preferably used.

As a place where the dialysis probe is placed,
Not only in the solution to be measured collected in a container such as a beaker or a test tube, but also in a living body such as a brain of a human or an animal, a tissue or a blood vessel, it can be appropriately selected according to the purpose. One dialysis probe may be used, or two or more dialysis probes may be used. In the present invention, instead of the enzyme sensor flow cell 30 in the above embodiment, various enzyme sensor flow cells selected according to the purpose can be used.

The enzyme sensor flow cell may be provided at any position of the trace component measuring device. One or two or more enzyme sensor flow cells may be used. The enzyme sensor in the enzyme sensor flow cell is not particularly limited as long as it can measure a trace amount of component by utilizing an enzyme reaction, and a sensor having an enzyme membrane on which an enzyme is immobilized can be used. A commercial item can be used for an enzyme sensor.

One enzyme sensor may be used, or two or more enzyme sensors may be used. At that time, the type of enzyme sensor is
You may use 1 type or 2 or more types. In addition, the enzyme reaction used in the enzyme sensor can be selected according to the measurement target, and for example, a trace component to be measured is
In the case of glucose, it is an oxidation reaction of glucose, and in the case of lactic acid, it is an oxidation reaction of lactic acid. The enzyme sensors in this case are a glucose sensor and a lactate sensor, respectively.

Any principle may be adopted for the measurement of trace components in the enzyme sensor. For example, when the trace component is glucose, hydrogen peroxide produced in the oxidation reaction of glucose catalyzed by glucose oxidase or oxygen consumed is detected by a current method using a platinum electrode or the like as a working electrode to give glucose. The principle of measuring the concentration can be adopted. Further, for example, the pH change when the gluconolactone produced by the above reaction reacts with water to form gluconic acid is
The principle of measurement by the potential method using the H electrode can be adopted.

Further, as the enzyme sensor 31, a mediator type enzyme sensor in which an electron mediator such as ferrocene is immobilized together with an enzyme can be used. The size, shape, structure, etc. of the flow cell are not particularly limited, and can be formed of an appropriately selected material. Also in the other embodiments described above,
Since the discharge characteristics of the infusion pump, the dialysis characteristics of the dialysis probe, and the output characteristics of the enzyme sensor are as described in the above embodiments, the temperature dependence of the trace component measuring device can be reduced. In this case, the action described in the above-described embodiment can be realized except that the trace components to be measured are different.

[0051]

According to the present invention, output fluctuations due to temperature dependence and the like can be reduced, and since a driving member, a power source, and the like in the pump are unnecessary, it is simple and continuous, and measurement error is reduced. It is possible to provide a small amount of a trace amount measuring device which can be measured with a small amount of accuracy and is convenient to handle, and a trace amount measuring method. Since the trace component measuring device and the trace component measuring method of the present invention can continuously measure the trace component by a safe and simple operation, it is suitable for the measurement of the trace component contained in the biological fluid. High utility value in the medical field.

In addition, since the protein such as albumin is hardly dialyzed during the measurement, it is not necessary to perform the operation such as deproteinization. Therefore, the measurement operation is simple and the loss of trace components to be measured is low. Since there are few, the accuracy is high. Further, since the enzyme sensor flow cell is not contaminated with protein or the like, deterioration of the enzyme sensor can be extremely reduced. Since the structure of the device is simple, maintenance, inspection, replacement, etc. are easy, and therefore handling is convenient. Moreover, since it is small, it can be portable and does not require a large space when used.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of a trace component measuring device of the present invention.

FIG. 2 is a schematic explanatory view showing an example of an infusion pump having a dialysis container provided with a hollow fiber-shaped semipermeable membrane.

FIG. 3 is a schematic explanatory view showing an example of a perfusion solution supply container having a perfusion solution chamber which is a variable volume envelope in an infusion pump.

FIG. 4 is a graph showing the relationship between the discharge amount of the infusion pump and the temperature.

FIG. 5 is a graph showing the relationship between glucose concentration taken in by dialysis and temperature.

FIG. 6 is a graph showing the relationship between the output of an enzyme sensor and temperature.

FIG. 7 is a graph showing the relationship between the output of the enzyme sensor and the temperature in the conventional device and the trace component measuring device of the present invention.

[Explanation of sign]

 1 injection pump 2 spout 3 perfusion liquid supply container 4 mover 5 perfusion liquid chamber 5a perfusion liquid 5b perfusion liquid containing trace components 6a aqueous solution outflow pipe 6b water outflow pipe 7 osmotic pressure vessel 8 water hole 9 support 10 semipermeable membrane 11 aqueous solution 11a, 11b aqueous solution chamber 12a, 12b water filling chamber 13 water filling container 14 rubber stopper 16 partition member 20 dialysis probe 21 needle shaft 22 dialysis membrane 23 inlet 24 outlet 25 reinforcing material 30 enzyme sensor flow cell 31 enzyme sensor 32 flow cell 33 Enzyme membrane 34 Lead wire 40a, 40b, 40c Tube

Claims (4)

[Claims] 1. A perfusion solution is discharged by an infusion pump using an osmotic pressure of a solution as a driving source, the discharged perfusion solution is stored in a dialysis probe, and a trace amount of component to be measured is dialyzed into the perfusion solution. A method for measuring a trace component, which is characterized in that a perfusate containing a trace component is taken in and sent out, and the trace component contained in the sent out perfusate is measured by an enzyme sensor flow cell. 2. The trace component measuring method according to claim 1, wherein the trace component is glucose. 3. An infusion pump that discharges a perfusate using an osmotic pressure of the solution as a driving source, and a container that contains the discharged perfusate,
It has a dialysis probe for producing a trace component-containing perfusate by incorporating a trace component to be measured into the perfusate by dialysis and sending this, and an enzyme sensor flow cell for measuring the trace component contained in the delivered perfusate. A trace element measuring device characterized in that 4. The trace component measuring device according to claim 3, wherein the trace component is glucose.