JPH0233168Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a component measuring device that measures a specific component in a body fluid while flowing the body fluid. Specifically, when measuring blood glucose level etc. with blood etc. as a test subject, blood etc. is injected into a flowing buffer solution and mixed. The present invention relates to a measuring device in which a flow resistance section for preventing bubble generation is provided in the device, which measures by contacting an enzyme electrode in a flowing state. For example, measuring blood sugar levels is essential in determining diabetes, and as the prevalence of diabetes increases, the frequency of testing at medical institutions is rapidly increasing. In addition, the importance of biochemical tests in modern medical care, not just blood sugar levels, is increasing, and automatic measuring devices are being developed.
No. 84346) and the like provide an apparatus that can relatively accurately and quickly measure chemical components in various body fluids (including blood, urine, etc.) using oxygen reactions. By the way, when measuring while flowing the sample body fluid, the above measuring device uses a pump to send the sample fluid, a preheating coil that heats the buffer solution to body temperature, and a preheating coil that heats the buffer solution to the body temperature. Bubbles were sometimes generated in the mixing device used to uniformly mix the injected liquid mixture. If such bubbles flow through the measurement device together with the mixed liquid and pass through the enzyme electrode or adhere to the electrode surface, the electric field distribution pattern caused by the enzyme reaction will be disrupted and measurement noise will appear, making it difficult to measure the chemical components in the sample body fluid. Accuracy decreases. Therefore, the inventors of the present invention have attempted to provide a device that can improve measurement accuracy by preventing the generation of bubbles inside the device as much as possible. In other words, the configuration of the present invention that achieves the above object is as follows: an injection part for injecting a sample liquid into a flowing buffer solution, a mixing device for mixing these liquids, and a device for bringing the mixed liquid into contact with an enzyme electrode in a flowing state. In a body fluid component measuring device in which a measuring section for measuring the measured liquid and a discharging section for discharging the measured mixed liquid to the outside of the system are connected by a line pipe, a 3.
The gist of this is that a fluid flow resistance section is provided in the line pipe upstream of the pipe. The configuration and effects of the present invention will be specifically explained below with reference to the drawings, which are examples. However, the following example is just one specific example, and the design of the flow resistance part is changed in accordance with the purpose described above and below. All of these are included within the technical scope of the present invention. Figure 1 is a system diagram showing the concept of the body fluid component measuring device to which the present invention is applied, showing a measurement line It consists of a line Y and a discharge line Z extending from a branch part B to a discharge part C, and these are connected by a line pipe. The buffer solution in the buffer solution storage section A is sucked up by the inline pump 8, and the buffer solution supplied to the measurement line X is heated to the optimum measurement temperature (usually
Increase the temperature to 37℃). The heated buffer solution reaches the sample port 2, and the test body fluid is injected into the buffer solution flowing inside the port 2. The injection of the test body fluid described above takes into consideration the large pressure loss within the line pipe. Since the injection is carried out at a pressure higher than atmospheric pressure, manual press-fitting is performed with the atmosphere sealed. Alternatively, instead of the manual method, an automatic injection method using an autosampler 17 or the like may be adopted. The flow buffer that received the sample injection was
The sample and buffer solution are mixed sufficiently (hereinafter referred to as mixed solution) by a mixing device 3, which is provided in order to ensure sufficient mixing before reaching the measuring section 5. leading to. Measuring part 5
In this method, the liquid mixture is brought into contact with the enzyme electrode 4 in a fluid state, and when the liquid mixture comes into contact with the enzyme electrode, the concentration of the target component in the body fluid to be examined is determined by the action of the enzyme electrode. The measurement unit 5 can prevent measurement errors due to air entering from the outside or gas generated inside, and can also allow the liquid mixture that has reached the surface of the enzyme electrode to sufficiently contact the surface and quickly flow out. It is a flow cell type with a similar structure. Further, the computer 13 performs the calculation and recording of the concentration of the target component. The mixed liquid after the measurement is transferred to the measuring section 5 and the discharging section C.
It passes through a flow resistance section 6 provided in the line pipe between the three-way tank 7 provided in the branch road B immediately before the flow.
Although the configuration of the flow resistance section 6 is arbitrary, the essential point is that it applies back pressure to the sample liquid flowing in the line pipe, and prevents the flow of the liquid by the pump and the air bubbles generated in the system by the preheating coil, mixing device, etc. Since it is provided to prevent the fluid from expanding, any fluid resistance section for the purpose of increasing the fluid pressure within the system can be used in the present invention. FIG. 2 is a partially cutaway sectional view showing an example of the flow resistance section 6 in an enlarged manner.
It is wrapped in a spiral shape. It is recommended that the inner diameter of the appropriately used resin tube be 0.5 to 1 mm and the length be about 1000 mm. And the supply port 11 of the flow resistance section 6
The mixed liquid that has entered further is discharged from the discharge port 12. That is, the mixed liquid is advanced by the in-line pump 8 and flows in through the supply port 11 of the flow resistance section 6, but it exhibits flow resistance by rotating in the spiral tube. This results in an increase in the back pressure of the buffer solution and mixed solution, which prevents the generation of bubbles within the measurement line X, and further suppresses the expansion of the generated bubbles to reduce the surface area. On the other hand, the mixed liquid discharged from the discharge port 12 of the flow resistance section 6 is discharged from the discharge line Z to the discharge section C via the three-way tank 7 provided at the branch point B. The three-way kettle 7 forms a closed loop extending from the measurement line X to the return line Y outside the measurement time.
At the stage of measurement, the sample is injected and at the same time the three-way socket 7 is switched to connect the measurement line X to the discharge line Z. Therefore, during normal times, the buffer solution is circulated to prepare for the start of measurement, and after the sample is injected, the tank 7 is switched so as to discharge the sample to the discharge line Z. In addition, if air bubbles generated in the system remain, another three-way pump 14 is provided upstream of the in-line pump 8 as a means for discharging these bubbles in preparation for the next measurement. It is possible to blow air into the system using an air compressor or the like by switching the air pressure and degassing the air together with the air (details have been filed separately). In order to investigate the influence of the presence or absence of the flow resistance section 6 on the measurement results, the concentration was measured using the same body fluid component measuring device using a glucose standard solution with a concentration of 150 mg/dl. First, a flow resistance part is installed and measured, then the flow resistance part is removed and measured,
Furthermore, the measurement experiment was repeated by disposing the flow resistance section again and performing the measurement three times. The number of data per run was 36, and the average value, standard deviation, CV value, and average of the CV values were determined. The results are shown in Table 1.

[Table] It can be seen from Table 1 that by providing the flow resistance section according to the present invention, variations in data are reduced and stable measurement results can be obtained. Since the device of the present invention is constructed as described above,
It has become possible to prevent the generation of air bubbles, reduce variations in measured values, and quickly and accurately measure specific components in body fluids.

[Brief explanation of the drawing]

Figure 1 is a system diagram showing the overall concept of the device of the present invention;
FIG. 2 is a partially cutaway sectional view showing an enlarged main part. A... Buffer storage part, B... Branch part, C... Discharge part, 1... Preheating coil, 2... Sample port, 3... Mixing device, 4... Enzyme electrode, 5... Measuring part, 6... Flow resistance part, 7... 3-way lock, 8
...Inline pump, 9... Core fitting, 10...
...Fluorine resin pipe, 11... Supply port, 12... Discharge port, 13... Computer, 14... 3-way socket.

Claims (1)

[Scope of utility model registration request] an injection part for injecting a sample fluid into the flow buffer;
It consists of a mixing device that mixes these liquids, a measurement unit that brings the mixed liquid into contact with the enzyme electrode in a fluid state, and a discharge unit that discharges the measured mixed liquid to the outside of the system, all connected by a line pipe. A body fluid component measuring device, characterized in that a fluid flow resistance section is provided in a line pipe downstream of the measuring section and upstream of a three-way socket provided immediately before the discharge section. .