JPS6283649A - Blood-sugar measuring device - Google Patents

Abstract

PURPOSE:To simplify operation by perfectly removing the substance adhered to the surface of an electrode, by detecting an oxidizing current by the use of a measuring electrode, an opposed electrode and a reference electrode and subsequently applying voltage capable of electrolyzing water between the measur ing electrode and the opposed electrode and washing the surface of the electrodes with generated gas. CONSTITUTION:Blood is added to a sensor part 8 to perform the reaction of enzyme with glucose and sweep voltage is applied to the non-reversal input terminal 9 of an operational amplifier 10. Hereupon, an oxidizing current flows to a measuring electrode. Said oxidizing current is converted to voltage through an operational amplifier 11 and a resistor 12 to be outputted to an output termi nal 14. The concn. of glucose in blood is obtained from the peak value of the output at said terminal 14. In washing the sensor part 8, the input voltage of the input terminal 9 is brought to 0V and a switch 13 is subsequently closed to apply voltage capable of electrolyzing water between an opposed electrode 3 and the measuring electrode 2 to generate oxygen from the opposed electrode 3 hydrogen gas from the measuring electrode 2 and to detach the substances adhered to the electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hand-held blood glucose meter that is used in the medical field and at home to detect the glucose concentration in blood.

BACKGROUND OF THE INVENTION Conventionally, in a blood glucose meter using this type of electrode system, after the measurement is completed, the electrode surface is cleaned by wiping off deposits with water, alcohol, or the like.

Problems to be Solved by the Invention However, in the conventional electrode cleaning method using water, lipids, proteins, etc. in blood that are firmly attached to the electrode surface are not completely removed, and the electrode surface area gradually decreases. Since the response of the oxidation current changes and the blood glucose measurement value fluctuates, it was necessary to completely remove the deposits on the electrode surface using alcohol'Jk.

SUMMARY OF THE INVENTION An object of the present invention is to provide a blood glucose meter having an electrode function in which deposits on the electrode surface can be completely removed by wiping with only water.

Means for Solving the Problems The present invention uses an electrode system consisting of a measurement electrode, a counter electrode, and a reference electrode provided on an insulating substrate to react an enzyme, an oxidized electron acceptor, and blood glucose to generate In a measuring device that measures the concentration of glucose in blood by detecting the concentration of reduced electron acceptors as an oxidation current with the electrode system, after detecting the oxidation current, a voltage is applied between the measurement electrode and the counter electrode to The structure is such that electrolysis is carried out.

Function: With this configuration, the gas generated at the constant electrode and the counter electrode removes deposits that adhere firmly to the electrode surface from the electrode, making it possible to completely clean the surface of the electrode by wiping it with water only. be.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 shows a part of a sensor that causes a reaction between glucose and an enzyme. An electrode system consisting of a measuring electrode 2, a counter electrode 3, and a reference electrode 4 is constructed by embedding platinum in an insulating substrate 1. A liquid retaining layer 5. Blood cell filtration layer6. A reaction layer 7 carrying glucose oxidase and potassium ferricyanide 7 is provided on a pulp nonwoven fabric. When blood is added to this reaction layer, glucose in the blood is oxidized by glucose oxidase, and at the same time potassium ferricyanide is reduced to potassium ferrocyanide. Blood cells from the reacted blood are removed by the blood cell filtration layer 6, and the blood is retained on the electrode by the liquid retaining layer 6. Potassium ferrocyanide is oxidized by sweeping the potential of the reference electrode toward the cathode based on the measurement electrode, and an oxidation current flows.

This oxidation current corresponds to the concentration of potassium ferrocyanide produced and the glucose concentration in the blood.

FIG. 2 is a circuit diagram of the measuring instrument of the present invention. 8 is a part of the sensor shown in FIG. The reference pole is connected to the inverting input terminal of the operational amplifier 100, and the counter electrode is connected to the output terminal of the operational amplifier 10. Further, the measurement pole is connected to the inverting input terminal of the operational amplifier 11, and then connected to the output terminal 14 of the operational amplifier 11 through the resistor 12 to form a potentiostat. After blood is added to the sensor part 8 and the enzyme reacts with glucose in the blood, a voltage of -o is applied to the non-inverting input terminal 9 of the operational amplifier 10 in a sawtooth manner between O and 0.1V. When a sweep voltage of 1 V/sec is applied, the oxidation current flows through the measurement electrode. The operational amplifier 11 converts the oxidation current value into a voltage using the resistor 12 and outputs it to the output terminal 14 .

The peak value of the oxidation current corresponds to the concentration of the generated potassium ferrocyanide and the glucose concentration in the blood.

The sensor part 8 is cleaned by setting the input voltage of the input terminal 9 to OV, then closing the switch 13 made of a transistor or the like, and applying a voltage that causes water to electrolyze between the counter electrode and the measurement electrode. As a result, oxygen gas is generated from the counter electrode on the anode side, and hydrogen gas is generated from the measurement electrode on the cathode side, making it possible to remove stubborn deposits from the electrode surface.

In the above example, the switch 13 was turned on to the measurement electrode to apply a voltage that would cause water to electrolyze. However, the potential of the counter electrode may be changed, and the point is to set the voltage that causes water to electrolyze between the counter electrode and the measurement electrode. It is a good idea to apply the gas and clean the electrode surface with the generated gas.

Effects of the Invention As described above, according to the present invention, there is no need for alcohol to clean lipids, proteins, etc. in blood that are firmly attached to the electrode surface, and it can be easily wiped off with water only. It is possible to provide an operable blood glucose meter.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a part of a sensor of a blood glucose meter according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of the same blood glucose meter. 1... Board, 2... Measuring pole, 3...
- Counter electrode, 4...Reference electrode, 7...Reaction layer.

Claims (1)

[Claims] Using an electrode system consisting of a measurement electrode, a counter electrode, and a reference electrode provided on an insulating substrate, the concentration of reduced electron acceptors produced by the reaction between enzymes, oxidized electron acceptors, and blood glucose is measured using an oxidation current. A blood glucose meter that detects the oxidation current and measures the concentration of glucose in the blood, and after detecting the oxidation current, applies a voltage capable of electrolyzing water between the measurement electrode and the counter electrode,
A blood glucose meter characterized in that the electrode surface is cleaned with generated gas.