JPS60183546A - Quantitative determination meter for blood component - Google Patents

Abstract

PURPOSE:To prevent deterioration of sensors and to extend the life thereof by providing means of applying reverse bias to the sensors. CONSTITUTION:The constant voltage from a constant voltage generating circuit 20 is applied to a detecting part 21 for the current of a material to be inspected and a detecting part 22 for the current of a disturbing material. The outputs from the parts 21, 22 are inputted via current/voltage converting circuits 23A, 23B, amplifier circuits 24A, 24B, filter circuits 25A, 25B and A/D converting circuits 26A, 26B to an arithmetic circuit 27. The circuit 27 calculates the difference between the detected electricity quantity of the material to be inspected and the detected electricity quantity of the disturbing material and displays the calculated value on a display part 28. A bias changeover circuit 20A operates only for the prescribed time after turning on of a power source switch and reverse bias is applied to the parts 21, 22. Impurities are thereby isolated from the parts 21, 22 and the decrease in sensitivity is prevented.

Description

[Detailed Description of the Invention] [Technical Field] The present invention enables the determination of test substances such as glucose, cholesterol, and uric acid in blood by eliminating the effects of interfering substances that cause errors in the determination of these test substances. "Blood component determination"
It is related to.

[1+F technology] Conventionally, when the biosensor, that is, the electron θ for detecting the analyte and the electrode for detecting the interfering substance, deteriorate, the amount of electricity generated decreases, and the amplifier that amplifies the amount of electricity is This meant that it would have to be used in areas where it was not available, and there was a risk of a large error.

In addition, the Ministry of Use was distrustful of the sensor and had to replace it with a new sensor even though the sensor had not completely deteriorated, which was a waste of money. Note that there are known methods of determining the state of deterioration based on the number of times the product has been used or the amount of time it has been used, but this is not a sophisticated means of recognition.

[Purpose of the invention]

An object of the present invention is to provide a blood component quantitative meter that can prevent sensor deterioration and maintain a long service life.

[Disclosure of the invention]

This invention is configured to flow a reference solution through a flow channel system and then flow a test substance, and includes a flow channel through which a carrier liquid of the test substance flows, and an inlet for pressurizing an interfering substance into this flow channel. ,M
ii) an injection port for the test substance into the flow path, an interfering substance detection electrode inserted into the flow path downstream of the interfering substance injection;
1: An analyte detection electrode inserted into the flow path, a calculation unit that corrects the output electricity amount of the analyte detection electrode based on the output electricity Rb of the interfering substance detection electrode, and this The apparatus is equipped with a display section for displaying the results of the Heha calculation by the arithmetic section, and a bias switching circuit that switches between forward and reverse biases to apply bias to the analyte detection electrode and interfering substance detection electrode.

A first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

FIG. 1 is a block diagram for detecting, calculating, and displaying a test substance. 20 is a constant voltage generation circuit, 2] is a current detection unit for the electrode for detecting a test substance (hereinafter also referred to as a sensor), and 22 is a current detection unit for the interfering substance detection electrode (hereinafter also referred to as a sensor). , 23Δ523B is a current/voltage conversion circuit, 24Δ, 24B is an amplifier circuit, 25A, 25
B is a filter circuit, 26Δ, 26B is an A/D conversion circuit,
27 is an arithmetic circuit (arithmetic unit), and 28 is a display unit. The arithmetic circuit 27 performs the calculation S=a-b based on the detected quantity of electricity (digital quantity) a of the test substance and the detected quantity of electricity (digital quantity) b of the interfering substance, and the display section 28 displays the calculated value S. to be displayed digitally.

FIG. 2 is an overall configuration diagram of the blood component quantitative meter.

This device is comprised of a storage tank 30 for carrier liquid (slow induction liquid) 29, a metering pump 31, an injector 32, a liquid flow damper 33, a sensor section 34, a waste liquid tank 35, and a flow path 36 that connects these in order. . Sensor section 34
are an analyte detection electrode 37 and an interfering substance detection electrode 38.
and a counter electrode 39, each of which is connected to a constant voltage generating circuit (battery) 20, 20 via an ammeter 40, 40.

In addition, an analog data input section 41 that is a detection current, and separate sensitivity two-stage switching circuits 42 and 42 are provided, and these are connected to the A/D
The central processing unit (CPU) 2 of the 8-bit microcomputer via the conversion circuit 26 (26A, 26B in FIG. 3)
7 (arithmetic circuit 27 in Figure 1), and further connected to LE
It is connected via a D (light emitting diode) driver 43 to a decile display section 28 and a 0/various pie 1 display section 44 . 45 is a syringe for injector 32;

FIG. 3 shows the front panel 51 of the main body of the apparatus. This front panel 51 includes a digital display section 28, various pilot display sections 44, a solution containing only the test substance (first reference solution), and a solution containing only interfering substances (second reference solution).

a common inlet 46 (this is in the injector 32) for a solution of the analyte (no analyte) and a solution of the analyte (sample solution);
A connection port 47 for the carrier liquid suction tube 57, a connection port 48 for the waste liquid tube 58, a power switch 49, and a pump switch 5o are provided. The pyro and gating display sections 44 display an injection waiting instruction 44a, which is L E I), respectively.
During measurement 44t1, first reference liquid injection instruction 44. c, second
Base liquid injection instruction 44d, sample solution injection instruction 44. e,
Sensor replacement instruction 4.4 Each display part of f is marked with the installation number. Figure 4 shows the appearance of the entire device in two pieces.

Next, a description will be given of how this device is used to quantify blood sugar levels, that is, glucose.

(2) When the power switch 49 is turned on, the metering pump 31 is activated, and the carrier liquid 29 having an l-H of approximately 7.5 flows into the channel 3G. The flow rate is 3 ml/min. career lll
29 reaches the sensor unit 34.
"E I) ll 4□" flashes (for about 2 minutes).

■ When the gear rear fluid 29 reaches the sensor section 34 Q;Z,
The LED 44c indicating the first reference liquid injection instruction blinks.

Accordingly, the first reference solution, Glue:1-
Inject only the solution. This will cause the LED being measured to
44 b lights up. The output power is obtained from the analyte detection electrode (i.e., the immobilized enzyme electrode) 37, and is displayed as 250 on the digital display section 28 (a = 25).
0 (nv/dl)), there is no output from the interfering substance detection electrode 38. Electrode 37 for glucose at this time
The sensitivity of is stored in the microcomputer's memory.

FIG. 5 is a circuit diagram of a first embodiment of the invention. 1st
Bias switching circuit 20/\ and each part 20 in the solo diagram shown in the figure
．． 2], 22.23A, and 23B.

By turning on the power switch 49, a reverse bias is applied to the sensors 21 and 22 as shown in the figure (A>).
The bias switching circuit B shown in FIG.
Current flows through the relay coil 60, the relay contacts 61 to 63 in Figure (A) operate as shown by the arrows, and the sensors 21, 22
is subject to normal bias.

Therefore, during the injection waiting time from when the power is turned on until the carrier liquid 29 is filled, the sensors 21 and 22 are reverse biased and the first group 48 liquid injection instruction (D I-E
After D 44 c flashes, normal bias is applied.

The reason why the reverse bias is applied to the sensor is as follows.

Normally, when blood glucose levels are measured, impurities in the blood adhere electrically to the sensors 2122 for detecting test substances and interfering substances, and the sensitivity of the sensors 21 and 22 decreases. To go. In order to remove the impurities, apply a reverse bias to pin 7'4J21.22.
22 and it is flushed away by a carrier liquid 28;
This can prevent low F sensitivity.

As described above, the time required for injection until the flow path is filled with the carrier liquid 29 after the power is turned on is used to apply a reverse bias to the sensors 2 and 22, so that impurities that have landed on the sensor 2 are
122 and is carried away by carrier lIν29. Therefore, the sensors 21 and 22 are cleaned before calibration and measurement, and deterioration of sensitivity due to impurities can be prevented.
This has the effect of increasing the lifespan.

A second embodiment will be described based on FIG. In Figure 6 (
A) is the same as (A) in FIG. In FIG. 6(B), the heath of the transistor Tr2 is connected to the LED driver 43 via the timer 64, and the relay coil 68 is connected to the collector.
Connect it. FIG. 6(C) is a waveform diagram at the X point and Y point of the circuit.

Normally, measurements are taken when the syringe 45 is inserted into the injection port 46 in the state shown in Figure 6 and the sample solution is injected.
ED4.4b lights up and measurement starts. When the measurement is completed and the measured value is displayed on the display section 28, L
E D 44. b disappears, L TE', D -14
e (SAMPLE) lights up. When the measurement is completed, the fifth
The "II" signal enters the X part of the diagram, LEr)
4/1c (SAMIIL14) lights up. When timer 64 receives the 1F signal, Kuimaro 4 turns ONL.
, as shown in Figure (C), the timer setting time T exceeds H.
During this time, the transistor Tr2 is turned on -ζ, the relay contacts 65, 66, and 67 are turned on, and a reverse bias is applied to the sensor 21, 22 in FIG. Then, when the timer set time T comes, the relay contacts 65.degree. 66.67 return to their normal state, and the normal bias is applied to the sensors 21.22. As mentioned above, applying a reverse bias to the sensors 21 and 22 can prevent a decrease in sensitivity.

Furthermore, if the measurement interval is very short when measuring a sample several times, that is, when the next sample is injected and measured while the sensors 21 and 22 are being reverse biased, measurement cannot be performed.

The third embodiment shown in FIG. 7 and FIG. 8 takes this measure. In other words, in order to prevent such a thing from happening, a limit switch 75 is provided at the injection port 46, and when the injection is made, the limit switch 751.1 is turned ON.
A signal enters the reset terminal of the timer 64 shown in the figure, the timer 64 changes from "H" to "L", and the relay coil 68 returns to its original state. Therefore, a normal bias is applied to the sensors 21 and 22, and the sample becomes ready for measurement.

Since a reverse bias is applied to the sensors 21 and 22 every time a sample is measured, the attached impurities are separated from the sensor 2i22 and washed away by the carrier liquid 29, and the sensors 21 and 22 are cleaned, thereby preventing a decrease in sensitivity due to impurities. Good accuracy and long life.

FIG. 9 shows a fourth embodiment. This is after the measurement is completed.
The relay 69 is opened for the timer set time 'F, and the sensor 2L is
, 22 are not biased (positive or reverse). By doing so, the attraction force to the impurities electrically deposited on the sensor 21.22 is removed, the impurity is washed away by the carrier liquid 29, and the sensitivity of the sensor 21.22 is prevented from decreasing.

When applying a reverse bias to the sensors 21, 22, impurities electrically attached to the sensors 2+, 22 are forcibly separated and washed away by the carrier liquid.

Therefore, when the bias is not reduced, the amount of impurities flushed out is less than when the reverse bias is reduced (although the effect is less than when the reverse bias is reduced, it is still effective.

Then, when the timer setting time T has elapsed, the relay contact 69 returns to its original state, so that the sensors 21 and 22 are biased.

〔Effect of the invention〕

According to this invention, impurities attached to the sensor can be removed by applying a reverse bias to the sensor, and measurement can always be performed with good sensitivity.

[Brief explanation of drawings]

FIG. 1 shows the first embodiment of this invention and the second embodiment.
The figure is a schematic R configuration diagram, Figure 3 is a front view of the panel front plate, Figure 4 is a perspective view of the whole, Figure 5 is an electric circuit diagram, and Figure 6 is an electric circuit diagram of the second embodiment. , FIG. 7 is a sectional view of a portion of the third embodiment, FIG. 8 is a front view thereof, and FIG. 9 is an electric circuit diagram of the fourth embodiment. 21... Electrode for detecting analyte, 22... Electrode for detecting interfering substance, 27... Arithmetic circuit, 28... Display section, 3
6... Channel, 46... Inlet, 64... Timer,
75...Suinochi, 13...Bias switching circuit 2
3A / (A) (B) 3A / Procedural Amendment (Mutsu) ], Indication of the case 1982 Patent Application No. 039364 2, Name of the invention Blood component quantitative meter 3, Person making the amendment Relationship to the case Applicant 4゜ Agent 5, date of amendment order voluntary amendment 6, specification subject to amendment 7, statement of contents of amendment, page 5, line 20, replace ``Figure 3'' with ``Figure 1''
I am corrected.

Claims (1)

[Scope of Claims] (1) A flow path through which a carrier liquid of a test substance flows, an injection port for an interfering substance into the flow path, an injection port for the test substance into the flow path, and an injection port for the interfering substance into the flow path. An interfering substance detection electrode inserted into the flow path further downstream from the analyte injection port, an analyte detection electrode inserted into the flow path downstream from the analyte injection port, and this analyte detection electrode. an arithmetic unit that corrects the output quantity of electricity based on the output electricity quantity of the interfering substance detection electrode; a display unit for displaying the calculation result of the /iti calculation unit; A blood component quantitative meter equipped with a bias switching circuit that switches and applies bias between forward and reverse directions. (2) After the bias switching circuit applies a reverse bias to the analyte detection electrode and the interfering substance detection electrode by turning on the power, and the flow path is filled with the carrier liquid,
Claim No. 1, wherein a normal bias is applied to the analyte detection electrode and the interfering substance detection electrode.
Blood component quantitative meter described in ). (31Rrj) The switching portion from the reverse bias to the normal bias in the bias switching circuit operates based on the test substance injection instruction signal (Claim 2)
Blood component quantitative meter described in ). (4) A patent claim in which the bias switching circuit is provided with a timer that operates based on the measurement path r signal and applies a reverse bias to the analyte detection electrode and the interfering substance detection electrode for the time limit. The blood component quantitative meter according to the range (1) above. (5) Blood component quantification according to claim (4), wherein the bias switching circuit includes a switch that resets the timer when a syringe is inserted into the injection port for the test substance. Total.