JPS62162953A - Instrument for measuring component in liquid - Google Patents

Abstract

PURPOSE:To obtain a small-sized instrument for measuring components in liquid which has good sensitivity of measurement and can make simultaneous polynominal measurements by using working electrodes immobilized with biocatalysts and counter electrode to form cylindrical bodies consisting of conductors to constitute part of a flow passage and fitting conductor rings connected with lead wires for respective electrodes to the outside peripheries of the cylindrical bodies. CONSTITUTION:The cylindrical bodies 1a-1c consisting of platinum and the cylindrical body 2 consisting of silver are connected to form part of the flow passage. The biocatalysts (enzyme) meeting the components to be measured are fixed to the inside peripheral face of the cylindrical bodies 1a-1c to constitute the working electrodes (enzyme electrode). The inside peripheral face of the body 2 is subjected to a silver chloride treatment to constitute the counter electrode. The conductor rings (preferably brass, etc.) are fitted onto the cylindrical bodies 1a-1c. The lead wires are connected by clips, etc. to the rings 3. The cylindrical bodies 1a-1c, 2 are joined via rings 6 made of a tetrafluoroethylene and tubes 5 made of the same material are connected to both ends. The measurement of the components in the body fluid, etc. is made by passing a liquid prepd. by injecting a sample into a carrier liquid to the flow pas sage and impressing potential to each working electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a liquid component measuring device used for detecting and measuring various substances such as measuring the concentration of body fluid components such as blood and urine.

[Background technology]

Biosensors in which biocatalysts (physiologically active substances) such as enzymes with molecular identification functions are immobilized have high sensitivity and high selectivity. For this reason, the field of application is expanding, including the field of clinical testing, and practical use is progressing.

As shown in FIG. 3, such a device has a flow path 31
A cell is equipped with a block 32 on which an enzyme membrane 34 is fixed on a platinum electrode 33 to which an enzyme electrode is attached, or as shown in FIG. 4, an enzyme electrode 42 is attached. The spacer 41 connects the attached block 44 and the block 45 attached with the counter electrode 43.
Conventionally, there have been two methods using cells that are combined via a cell to form a flow path 46. In FIG. 3, 35 is the opposite electrode.

These methods usually allow only one type of component (substrate) to be measured in one cell. Therefore, if you want to simultaneously measure multiple components in the same sample, you will need to prepare cells for each component and connect their channels in series, making the entire device large-scale. turn into. Furthermore, in order to increase the detection sensitivity, it is necessary to increase the size of the sensitive part of the electrode, which increases the size of the cell, which poses problems in terms of miniaturization of the device.

[Purpose of the invention]

In view of these circumstances, the present invention aims to provide a liquid component measuring device that is small, has high measurement sensitivity, and can simultaneously measure multiple items on the same sample.

[Disclosure of the Invention] In order to achieve such an object, the present invention provides a method for manufacturing a liquid submerged electrode comprising a working electrode on which a biocatalyst is immobilized, a counter electrode, and a flow path for guiding a liquid to be measured to the working electrode and the counter electrode. In the component measuring device, the working electrode and the counter electrode are respectively formed on the inner circumferential surface of a cylinder made of a conductor constituting a part of the flow path, and the outer circumference of each cylinder is provided with various types of electrodes. The gist of the present invention is an in-liquid component measuring device characterized in that a conductor ring to which a lead wire is connected is fitted.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, in this liquid component measuring device, part of the flow path of the liquid to be measured is formed by cylinders 1a, lb, lc,
It is formed by connecting four cylinders of 2. The three cylindrical bodies 1a, lb, and lc are made of platinum, and a biocatalyst, that is, an enzyme, corresponding to each component to be measured is immobilized on the inner circumferential surface of each to form a working electrode (enzyme electrode).
is configured. The number of working electrodes is not limited to that in the example. By increasing or decreasing the number of cylinders having working electrodes on the inner peripheral surface depending on the type of component to be measured, it is possible to simultaneously measure multiple items of desired components with one sample. Enzyme immobilization will be explained below using a glucose electrode as an example. First, glucose oxidase 2% by weight. An aqueous solution containing 5% by weight of albumin and 0.3% by weight of glutaraldehyde is prepared. A platinum cylinder treated with aminosilane is immersed in this aqueous solution for 5 seconds, and then dried at room temperature. According to this method, the enzyme is immobilized on both the inner and outer peripheral surfaces of the cylinder, so the enzyme immobilized on the outer peripheral surface is
Scrape it off with emery paper. Enzymes such as ascorbic acid oxidase, cholesterol oxidase, choline oxidase, etc. can be immobilized by a similar method as required. On the other hand, the remaining cylinder 2 is made of silver, and its inner peripheral surface is treated with silver chloride to serve as a counter electrode. Silver chloride treatment is carried out, for example, as described below. That is, a 0.75 N hydrochloric acid aqueous solution is prepared, the root is immersed in this aqueous solution, and electrolytic treatment is performed at a current density of 0.5 A/dm'' to cover the inner and outer peripheral surfaces of the cylinder with silver chloride. , as well as the working electrode, scrape off the silver chloride on the outer peripheral surface with emery paper.These cylinders 1a,
lb, lc, 2 each have a conductor ring 3 on the outer periphery.
・are fitted together and integrated. Conductor ring 3・
... is a clip or the like provided at the tip of the lead wire connected to each electrode when measuring the components of the liquid to be measured, and is provided to make it easier to clip and simplify the work of connecting the lead wires. The material is not particularly limited as long as it has good conductivity, but considering cost and strength,
Brass is preferred. The cylindrical bodies 1a, lb, lc, 2 are joined through a tetrafluoroethylene resin ring (trade name: Teflon, manufactured by DuPont) 6 as an insulating material, and a silicon tube 4 is inserted from above. ... are fitted and connected to cover this joint part to form a sensor part. Tetrafluoroethylene resin tubes 5, which serve as flow paths for the liquid to be measured, are connected to both ends of this sensor section, and are designed to be incorporated into a liquid component measuring device. In FIG. 2, 7 is a carrier liquid, 8 is a peristaltic pump that feeds a fixed amount of carrier liquid 7 into the flow path, 9 is a sample injector, 10 is a syringe that injects the sample liquid into the sample injector 9, 11 is a mixing coil, 12
is the waste liquid reservoir.

Next, an embodiment of the in-liquid component measuring device according to the present invention will be described in detail.

(Example) A glucose detection electrode, a cholesterol detection electrode, and an interfering substance detection electrode were prepared, each having an enzyme fixed to the inner circumferential surface of a platinum cylinder with an inner diameter of 1 mm, an outer diameter of 2 ml, and a length of 6 squares, each having an enzyme corresponding to the detection substance. . A root portion as a counter electrode having the same dimensions as this platinum cylinder and whose inner peripheral surface was treated with silver chloride was prepared. A brass ring with an inner diameter of 2 fins, an outer diameter of 7 fins, and a thickness of l n+ was fitted into these platinum cylinders and the root to form a single body. These are arranged in the order of an interfering substance detection electrode, a counter electrode, a glucose detection electrode, and a cholesterol detection electrode, and a tetrafluoroethylene resin ring with an inner diameter of 1.5 mm, an outer diameter of 1.51 mm, and a thickness of 11 mm is sandwiched between each electrode. Each electrode was insulated and isolated, and a silicon tube was placed over the joint to form a sensor section. The inner diameter of the silicone tube is 11. Outer diameter 2ml,
One with a length of 4+n was used.

The sensor section obtained in this way was incorporated into a flow system as shown in Figure 3, and a peristaltic pump was used in the flow path to flow the carrier liquid at a flow rate of 3 m/min, and the lead wire was attached to the brass ring with a clip. A potential of 0.7 v (vsAg/Agcl) was applied to each working electrode, and a 10 μρ serum sample was injected into the sample injector using a syringe to measure glucose and cholesterol levels in the serum. When the results were compared with the catalog values, as shown in Table 1, the measured values almost matched the catalog values. Furthermore, the repeatability in measurement was also good. Note that the tetrafluoroethylene resin tube constituting the flow path had an inner diameter of 0.5 ml and an outer diameter of 1.5 fins.

Table 1 The device for measuring components in liquid according to the present invention is not limited to the above embodiments. For example, it can be used as an artificial pancreas by connecting the inlet and outlet of the flow channel directly to the patient's blood vessels, continuously measuring blood sugar levels, etc., and automatically replenishing insulin. The material of the flow path connected to the sensor section and the rod/tube coupling section is not limited to tetrafluoroethylene. Any material may be used as long as it has excellent flexibility, chemical resistance, and is resistant to clogging. The cylindrical body may also be joined by adhesion.

〔Effect of the invention〕

Since the in-liquid component measuring device of the present invention is configured as described above, it is compact and has good measurement accuracy, and furthermore, it is capable of simultaneously measuring multiple items on the same sample. The lead wire can be easily connected by clipping the ring onto the clip, which is convenient.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the sensor section of one embodiment of the liquid component measuring device according to the present invention, FIG. 2 is a schematic diagram illustrating the whole, and FIG. 3 is a conventional liquid component measuring device. FIG. 4 is a side sectional view showing another conventional liquid component measuring device. la, lb, lc, 2...cylindrical body 3...conductor ring

Claims (4)

[Claims] (1) An in-liquid component measuring device comprising a working electrode to which a biocatalyst is immobilized, a counter electrode, and a flow path for guiding a liquid to be measured to the working electrode and the counter electrode, wherein the working electrode and the counter electrode are connected to the flow path. Each tube is formed on the inner peripheral surface of a cylinder made of a conductor that constitutes a part of the cylinder, and a conductor ring to which a lead wire to each pole is connected is fitted on the outer periphery of each cylinder. An in-liquid component measuring device characterized by: (2) The cylindrical body on the working electrode side is made of platinum, and the biocatalyst is fixed on its inner circumferential surface by a glutaraldehyde-albumin crosslinking method, and the cylindrical body on the counter electrode side is made of silver, and its inner circumferential surface Claim 1 in which silver chloride treatment is applied to
The in-liquid component measuring device described in 2. (3) The in-liquid component measuring device according to claim 1 or 2, wherein the conductive ring is made of brass. (4) The in-liquid component measuring device according to any one of claims 1 to 3, wherein the flow path other than the cylindrical portion is formed of a tube made of tetrafluoroethylene resin.