阅读说明：本技术 电解质测定装置以及电解质测定装置的电极部的连接状态的判定方法 (Electrolyte measuring device and method for determining connection state of electrode portion of electrolyte measuring device ) 是由 菅野宏章 今春真也 泷口享 水越诚一 于 2019-01-25 设计创作，主要内容包括：电解质测定装置(1)具有：电极部(10),包含相对于装置能够装卸的至少一个以上的离子选择性电极以及能够装卸的比较电极；信号输入电路(11),用于接受来自电极部(10)的电位；差动放大电路(15),对离子选择性电极和比较电极的输出进行差动放大；信号处理电路(14),使用差动放大电路(15)的输出信号进行离子浓度计算；直流电源,对电极部(10)施加超过离子选择性电极的电动势的直流电压；以及布线部(13),将信号输入电路与信号处理电路之间连结。在对电极部(10)施加直流电压之后,信号处理电路(14)基于经由布线部(13)计测到信号输入电路(11)的信号时的电位,判定电极部(10)的个别的电极的每一个相对于装置的连接状态。通过这样,能够简单地检知电极部相对于装置的连接状态的异常。(An electrolyte measurement device (1) is provided with: an electrode unit (10) including at least one ion-selective electrode and a detachable comparative electrode, the ion-selective electrode being detachable from the device; a signal input circuit (11) for receiving a potential from the electrode unit (10); a differential amplification circuit (15) which differentially amplifies the outputs of the ion-selective electrode and the comparison electrode; a signal processing circuit (14) that calculates the ion concentration using the output signal of the differential amplifier circuit (15); a DC power supply for applying a DC voltage exceeding the electromotive force of the ion-selective electrode to the electrode section (10); and a wiring unit (13) connecting the signal input circuit and the signal processing circuit. After applying a DC voltage to the electrode unit (10), the signal processing circuit (14) determines the connection state of each of the individual electrodes of the electrode unit (10) to the device based on the potential at the time of measuring the signal to the signal input circuit (11) via the wiring unit (13). Thus, it is possible to easily detect an abnormality in the connection state of the electrode portion to the apparatus.)

1. An electrolyte measuring apparatus, characterized in that,

comprises the following steps:

an electrode unit including at least one ion-selective electrode and a detachable comparative electrode, the ion-selective electrode being detachable from the apparatus;

a signal input circuit for receiving a potential from the electrode unit;

a differential amplification circuit for differentially amplifying outputs of the ion selective electrode and the comparison electrode; and

a signal processing circuit for performing ion concentration calculation using the output signal of the differential amplifier circuit,

the electrolyte measurement device comprises:

a direct current power supply that applies a direct current voltage exceeding an electromotive force of the ion-selective electrode to the electrode section; and

a wiring section connecting the signal input circuit and the signal processing circuit,

after the direct-current voltage is applied to the electrode portion, the signal processing circuit determines a connection state of each of the individual electrodes of the electrode portion with respect to a device based on a potential at the time of measuring a signal to the signal input circuit via the wiring portion.

2. The electrolyte measuring apparatus according to claim 1,

one end of the electrode part is grounded, the other end of the electrode part is connected with the signal input circuit,

a capacitor having the other end grounded is connected to a part of the signal input circuit on the electrode side,

the signal processing circuit measures a residual potential of the capacitor after the capacitor is charged from the dc power supply, and thereby determines a connection state of each of the individual electrodes.

3. The electrolyte measuring apparatus according to claim 2,

the dc power supply is a power supply for an operational amplifier disposed in the signal input circuit.

4. The electrolyte measuring apparatus according to claim 1,

a ground and a DC power supply are disposed at one end of the electrode section so as to be selectively connectable via a switch,

a rectifier circuit portion of a signal input circuit is disposed at the other end of the electrode portion, a capacitor of the rectifier circuit portion is grounded via a switch,

the signal processing circuit measures a voltage applied to the electrode portion from the dc power supply in a state where the capacitor is not grounded, and thereby determines the connection state of each of the individual electrodes.

5. The electrolyte measuring apparatus according to any one of claims 1 to 4,

a liquid ground electrode is disposed on the electrode portion.

6. A method for determining a connection state of an electrode portion of an electrolyte measuring apparatus,

the electrolyte measurement device comprises:

an electrode unit including at least one ion-selective electrode and a detachable comparative electrode, the ion-selective electrode being detachable from the apparatus; a signal input circuit for receiving a potential from the electrode unit; a differential amplification circuit for differentially amplifying outputs of the ion selective electrode and the comparison electrode; a signal processing circuit for performing ion concentration calculation using an output signal of the differential amplification circuit; a direct current power supply that applies a direct current voltage exceeding an electromotive force of the ion-selective electrode to the electrode section; and a wiring section connecting the signal input circuit and the signal processing circuit,

the determination method includes the steps of:

a step 1 of applying a direct-current voltage to the electrode section;

a step 2 in which a signal processing circuit measures a signal of the signal input circuit via the wiring portion; and

and 3, determining the connection state of the individual electrode relative to the device through the signal processing circuit.

Technical Field

The present invention relates to an electrolyte measurement technique for measuring the electrolyte concentration of a sample by supplying a diluted sample solution to a measurement unit using an ion-selective electrode, and more particularly to an electrolyte measurement device for measuring the ion concentration of an electrolyte (such as Na: sodium, K: potassium, Cl: chlorine) in urine, serum, or the like, and a method for determining the connection state of an electrode unit of the electrolyte measurement device.

Background

Conventionally, as an apparatus for measuring the concentration of electrolyte ions in urine, serum, or the like, an electrolyte measuring apparatus using an ion selective electrode has been known. As such a device, an ion selective electrode and a comparison electrode are used to measure an electromotive force of a sample solution generated by diluting a sample with a diluent, and an electromotive force of a reference liquid for comparison is measured. Then, the electrolyte ion concentration of the component to be measured contained in the sample solution is measured based on the measurement data of each of the sample solution and the reference solution.

Fig. 4 is a diagram showing a configuration of a conventional general electrolyte measuring apparatus. The electrolyte measurement device includes an ion-selective electrode unit 41 as a measurement unit, a sample supply unit 42 for performing pretreatment of a sample and supply to the electrode unit, a dilution container 43, a diluent supply unit 44, a standard solution supply unit 45, a pump unit 46, a signal input circuit 47 for measuring an electromotive force of the electrode unit, a differential amplification circuit 48, and a signal processing circuit 49.

The electrode portion 41 is provided with an ion-selective electrode (for example, sodium (Na), potassium (K), or chlorine (Cl)) and a comparative electrode (Ref).

Fig. 5 is a diagram showing a structural example of each ion-selective electrode of the electrolyte measuring apparatus. The ion sensitive membrane 51 attached to the support 52 of the ion selective electrode is brought into contact with the sample solution through a hole (a dotted line in the figure) provided in the flow path 56 and the support 52. The support 52 is held between the frame members 53 and 54, and an internal liquid such as a potassium chloride aqueous solution is filled in the internal space, and a partial battery is formed by a silver/silver chloride electrode 55 inserted into the space. The outer portion of the frame member of the silver/silver chloride electrode 55 is connected to an electrolyte measuring device via a detachable connection plug or the like (see, for example, patent document 3 listed below).

The sample solution prepared in the dilution container 43 of fig. 4 was introduced into each of these electrodes, and the potential generated from each electrode was measured. The potential generated at each electrode is introduced into the signal input circuit 47, converted into a potential difference based on the comparison electrode in the differential amplifier circuit 48, sent to the signal processing circuit 49, compared with the standard solution concentration, and the ion concentration in each sample is calculated.

As a conventional electrolyte measuring apparatus, the following techniques are disclosed: a technique of discriminating a measurement electrode and a structural electrode (for example, see patent document 1 listed below), a technique of detecting abnormalities such as disconnection or detachment of an electrode connector, and deterioration of an electrode (for example, see patent document 2 listed below), a technique of preventing deterioration of characteristics of an ion-selective electrode (for example, see patent document 3 listed below), and the like.

Prior art documents

Patent document

Patent document 1: japanese laid-open patent publication No. 2002-257782

Patent document 2: japanese patent laid-open publication No. 2016-

Patent document 3: japanese patent laid-open publication No. 2016-180630

Disclosure of Invention

Problems to be solved by the invention

In the prior art, the following problems exist: it is not easy to detect that there is no abnormality in the measurement.

Conventionally, in a general electrolyte measurement device, a plurality of ion-selective electrodes are mounted on the electrolyte measurement device by a detachable method. In this case, the individual electrodes may not be normally measured due to forgetting to connect the electrical terminals, poor connection, disconnection, or the like. However, even if there is a connection failure, disconnection, or separation of the electrode cable or the liquid ground cable, the measurement value is at the same level as that of the measurement of a normal sample, and it is difficult to distinguish whether or not the measurement is performed correctly.

For these reasons, the technique described in patent document 1 separately provides a detection sensor, a detection device dedicated to an electrode insertion detection switch, and the like, and determines the electrical connection state of each electrode. However, this method requires additional modification of the electrical structure, such as new installation of a sensor detection circuit in the measurement circuit, and has a drawback of increasing the complexity of the device.

In addition, in the technique described in patent document 2, there is a complication that an abnormality cannot be detected unless measurement is performed according to an actual procedure using a diluent and a standard solution. In addition, there is a technical disadvantage that connection failure, disconnection, and detachment of the electrode cable of the comparison electrode cannot be detected.

In view of the above problems, an object of the present invention is to easily detect an abnormality in the connection state of an electrode portion to an apparatus.

Means for solving the problems

In order to solve the above problem, an electrolyte measurement device according to the present invention includes: an electrode unit including at least one ion-selective electrode and a detachable comparative electrode, the ion-selective electrode being detachable from the apparatus; a signal input circuit for receiving a potential from the electrode unit; a differential amplification circuit for differentially amplifying outputs of the ion selective electrode and the comparison electrode; and a signal processing circuit for calculating an ion concentration using an output signal of the differential amplifier circuit, the electrolyte measurement device including: a direct current power supply that applies a direct current voltage exceeding an electromotive force of the ion-selective electrode to the electrode section; and a wiring unit that connects the signal input circuit and the signal processing circuit, wherein after the dc voltage is applied to the electrode unit, the signal processing circuit determines a connection state of each of the individual electrodes of the electrode unit with respect to the device based on a potential at the time of measuring a signal to the signal input circuit via the wiring unit.

According to the above configuration, particularly, a large dc power supply is intentionally connected to the electrode portion, a dc potential is generated in a part of the circuit, and the potential is measured, whereby an abnormality in connection of each electrode of the electrode portion can be easily detected.

The electrode unit is characterized in that one end is grounded, the other end is connected to the signal input circuit, a capacitor with the other end grounded is connected to a part of the electrode unit side of the signal input circuit, and the signal processing circuit measures a residual potential of the capacitor after the capacitor is charged from the direct-current power supply, thereby determining the connection state of each of the individual electrodes.

According to the above configuration, the dc power supply is disconnected after being connected to the capacitor provided in the signal input circuit, and the attenuation amount of the residual charge of the capacitor is measured, whereby an abnormality in connection of each electrode of the electrode portion can be easily detected.

The dc power supply is a power supply for an operational amplifier disposed in the signal input circuit.

According to the above configuration, it is possible to easily detect an abnormality in connection of each electrode of the electrode portion using the existing circuit configuration without using a special new component.

Further, a ground and a dc power supply are disposed at one end of the electrode unit so as to be selectively connectable via a switch, a rectifier circuit unit of a signal input circuit is disposed at the other end of the electrode unit, a capacitor of the rectifier circuit unit is grounded via a switch, a dc voltage is applied from the dc power supply to the electrode unit in a state where the capacitor is not grounded, and the signal processing circuit measures a voltage applied to the electrode unit, thereby determining the connection state of each of the individual electrodes.

According to the above configuration, it is possible to detect an abnormality in connection of each electrode of the electrode portion by a simple step of applying a dc voltage from the dc power supply to the electrode portion in a state where the capacitor is not grounded and measuring the voltage applied to the electrode portion by the signal processing circuit.

Further, a liquid ground electrode is disposed on the electrode portion.

According to the above configuration, the liquid ground electrode can be included to detect abnormal connection.

In addition, the method for determining a connection state of an electrode portion of an electrolyte measurement device according to the present invention is characterized in that the electrolyte measurement device includes: an electrode unit including at least one ion-selective electrode and a detachable comparative electrode, the ion-selective electrode being detachable from the apparatus; a signal input circuit for receiving a potential from the electrode unit; a differential amplification circuit for differentially amplifying outputs of the ion selective electrode and the comparison electrode; a signal processing circuit for performing ion concentration calculation using an output signal of the differential amplification circuit; a direct current power supply that applies a direct current voltage exceeding an electromotive force of the ion-selective electrode to the electrode section; and a wiring section connecting the signal input circuit and the signal processing circuit, the determination method including the steps of: a step 1 of applying a direct-current voltage to the electrode section; a step 2 in which a signal processing circuit measures a signal of the signal input circuit via the wiring portion; and a 3 rd step of determining, by the signal processing circuit, a connection state of the individual electrode with respect to the device.

According to the above configuration, particularly, a large dc power supply is intentionally connected to the electrode portion, a dc potential is generated in a part of the circuit, and the potential is measured, whereby an abnormality in connection of each electrode of the electrode portion can be easily detected.

In addition, the electrolyte measuring apparatus having the above-described configuration can detect an abnormality of the connection state of the electrode portions such as disconnection or disconnection of the plugs of the ion selective electrode, the comparative electrode, and the liquid ground electrode, without adding a dedicated detection device. Further, it is not necessary to actually measure the concentration of ions using a standard solution having a known ion concentration. Further, since the confirmation can be easily performed before the actual measurement is started, the sample measurement can be always performed in a normal state thereafter.

Effects of the invention

According to the present invention, the electrolyte measuring apparatus has an effect of easily detecting an abnormality in the connection state of the electrode portions, such as disconnection or disconnection of the plugs of the ion selective electrode, the comparative electrode, and the liquid ground electrode.

Drawings

Fig. 1 is a circuit configuration diagram of an electrolyte measurement device according to embodiment 1 of the present invention.

Fig. 2 is a detailed circuit diagram showing a signal input circuit of the electrolyte measuring apparatus according to embodiment 1.

Fig. 3 is a circuit configuration diagram of an electrolyte measurement device according to embodiment 2 of the present invention.

Fig. 4 is a diagram showing a configuration of a conventional general electrolyte measuring apparatus.

Fig. 5 is a diagram showing a structural example of each ion-selective electrode of the electrolyte measuring apparatus.

Detailed Description

(embodiment mode 1)

Embodiment 1 of the electrolyte measuring apparatus and the method for determining the connection state of the electrode portion of the electrolyte measuring apparatus according to the present invention will be described in detail below.

(description of the Circuit)

Fig. 1 is a circuit configuration diagram of an electrolyte measurement device according to embodiment 1 of the present invention. Fig. 1 shows the overall configuration of the electrolyte measurement device 1, which mainly relates to connection detection and determination of the electrode portion 10. Other components of the electrolyte measurement device 1 (the sample supply unit 42, the diluting container 43, the diluting liquid supply unit 44, the standard liquid supply unit 45, the pump unit 46, and the like in fig. 4) are similar to those in fig. 4, and the description thereof is omitted.

The electrode portion 10 is connected to a signal input circuit 11, and the output of the signal input circuit 11 is output to a signal processing circuit 14 via a differential amplifier 12.

The electrode portion 10 is provided with a sodium ion selective electrode (Na), a potassium ion selective electrode (K), a chloride ion selective electrode (Cl), a comparative electrode (Ref), and a liquid ground electrode (LG), and the flow paths 56 of the electrodes are aligned as shown in fig. 5. The ion selective electrode and the comparative electrode of the electrode unit 10 are attached to the electrolyte measuring apparatus 1 in a state of being detachable from the wiring of the apparatus main body by a plug or the like.

Here, the liquid ground electrode (LG) of the electrode portion 10 is provided for the purpose of grounding the potential of the liquid introduced into the flow path, and has a function of reducing the noise of the measurement system. The resistance between the terminal portion of the silver/silver chloride electrode 55 of each ion-selective electrode and the ground is about several hundred kiloohms (k Ω) in a state where the internal liquid of the ion-selective electrode and the solution in the flow path 56 are filled.

In the electrolyte measurement device 1 of the present invention, before the actual measurement operation of the sample, the determination operation of the connection state of the individual electrodes (the sodium ion-selective electrode (Na), the potassium ion-selective electrode (K), the chloride ion-selective electrode (Cl), the comparative electrode (Ref), and the liquid ground electrode (LG)) described in detail below is performed. The potential from each electrode of the electrode portion 10 is introduced from each silver/silver chloride electrode 55 (see fig. 5) to the signal input circuit 11 via a connector such as a plug.

Fig. 2 is a detailed circuit diagram showing a signal input circuit of the electrolyte measuring apparatus according to embodiment 1. The circuit of the plurality of electrodes provided to the electrode portion 10, respectively, is shown. In the following description, the circuit configuration is common to the respective ion-selective electrodes, and therefore the principle of the present invention will be described in detail with respect to the configurations of the comparative electrode and one ion-selective electrode.

The signal input circuit 11 is composed of a rectifier circuit unit 21 and a receiver unit 24. The rectifier circuit portion 21 includes a resistor 22 connected in series with a signal and a capacitor 23 connected in parallel with one end grounded. For example, in the rectifier circuit unit 21, a metal film element of 1 mega ohm (M Ω) is used as the resistor 22, and a thin film capacitor of 0.01 microfarad (μ F) is used as the capacitor 23. The signals from the electrodes are introduced into the rectifier circuit unit 21, noise and the like are removed, and then the signals are transmitted to the receiver unit 24. In the receiving unit 24, the signal is amplified by the operational amplifier 25 and output to the next differential amplifying unit 12.

The receiver 24 includes an operational amplifier 25, a positive dc power supply 26, a negative dc power supply 29, a high-resistance element 27, and a switch 28. A positive dc power supply 26 and a negative dc power supply 29 are connected to the operational amplifier 25 of the receiver 24 via a switch 28, and a positive dc voltage and a negative dc voltage of 5 volts are applied thereto, respectively. For the purpose of preventing an electrical short circuit between the positive and negative dc power supplies, a resistance element of about 10 kiloohms (k Ω) is used as the high-resistance element 27.

The output of the operational amplifier 25 is branched into two (see fig. 1). One of the outputs of the operational amplifier 25 is also transmitted to the signal processing circuit 14 via the wiring portion 13, and is used as a signal for determining a connection abnormality of a plug or the like of the present invention. The other of the outputs of the operational amplifier 25 is sent to the differential amplifier circuit 15 of the differential amplifier unit 12, and the differential amplifier circuit 15 amplifies a differential signal between the signal from each ion-selective electrode and the signal from the comparison electrode (Ref) and introduces the amplified signal into the signal processing circuit 14. The signal processing circuit 14 calculates the electrolyte ion concentration from the magnitude of the difference signal between the standard solution having a known concentration and the sample diluted solution having an unknown concentration.

(description of measurement sequence)

Next, a measurement procedure by the above-described electrolyte measurement device will be described. In this description, a process of detecting a connection abnormality of the electrode portion 10 will be described. First, the diluent is supplied to the electrode portion 10 to fill the flow path 56.

Then, in order to detect a connection abnormality (connection detection mode) of the electrode portion 10, the switch 28 of the receiving portion 24 in the signal input circuit 11 is turned off (disconnected), and the negative dc power applied to the operational amplifier 25 is cut off.

This forms a circuit grounded through the positive dc power supply of the operational amplifier 25, the rectifier circuit unit 21, and the flow path 56 of the electrode unit, and charges the capacitor 23 with a positive voltage (+5 volts). This voltage is a potential much higher than the potential induced by each ion-selective electrode in the electrode portion, for example, the maximum electromotive force of the Na ion-selective electrode. Under this circuit condition, the off time of the switch 28 becomes the charging time of the capacitor. The charging completion time of the capacitor 23 may be about 0.5 seconds, and then the switch 28 is short-circuited again to complete the charging of the capacitor 23, and the electrolyte measurement device returns to the normal measurement mode.

In this state, when a plug or the like of the electrode portion is normally connected, the residual charge of the capacitor 23 is discharged via the electrode portion 10. The discharge time constant of the capacitor 23 at this time is substantially determined by the resistance 22, the resistance between the terminal portion of the silver/silver chloride electrode 55 of each ion-selective electrode of the electrode portion 10 and the ground, and the capacitance of the capacitor 23.

Here, in practice, when the plug or the like of the electrode portion 10 is normally connected, the discharge is performed with the above-described discharge time constant. However, in the case of an abnormality such as disconnection of the electrode portion 10, the electric charge of the capacitor 23 is discharged due to the internal resistance of the operational amplifier 25, and therefore the decay rate of the residual potential thereof is significantly slower than that in the case of normal connection.

Therefore, in a state where the switch 28 is turned back on to apply a negative dc voltage to the operational amplifier 25 and the electrolyte measuring apparatus is returned to a normal measurement state, the potential appearing in the signal input circuit 11 is measured by the signal processing circuit 14 via the wiring portion 13. The potential measured at this time is based on the residual charge charged in the capacitor 23. In the case where the respective ion selective electrodes are normally connected, substantially zero volts is represented.

However, in the case where there is an abnormality such as plug-off, if the potential indicates a value higher than a predetermined value (for example, 3 volts) predetermined as a threshold value corresponding to the above-described positive voltage (+5 volts), it can be determined that the electric charge is not discharged from the capacitor 23 through the electrode portion 10, and therefore it can be determined that there is an abnormality in the connection of the electrode portion 10.

At this time, the signal processing circuit 14 outputs an abnormality notification to the outside, and can notify the user of an abnormality in connection of the electrode unit 10 by display or sound.

In addition, when the signals of the plurality of ion selective electrodes all at once have a high value, it is possible to suspect that the liquid-grounded (LG) cable is connected abnormally or disconnected, and the signal processing circuit 14 may notify that the liquid-grounded (LG) cable is connected abnormally.

After the measurement, in order to minimize the risk of applying an excessive external voltage to the electrode portion 10, it is preferable to return the switch 28 to the original state quickly and return to the normal measurement mode.

Further, a control unit or the like, not shown, provided in the electrolyte measurement device 1 may be configured to perform switching control of the switch 28 or the like, switch to the connection detection mode of the electrode portion 10 before the start of the normal measurement mode, and automatically execute the connection detection mode for a predetermined time.

(embodiment mode 2)

Hereinafter, embodiment 2 of the electrolyte measuring apparatus and the method for determining the connection state of the electrode portion of the electrolyte measuring apparatus according to the present invention will be described in detail.

(description of the Circuit)

Fig. 3 is a circuit configuration diagram of an electrolyte measurement device according to embodiment 2 of the present invention. In the electrolyte measurement device 1 shown in fig. 3, the same components as those in embodiment 1 (fig. 1 and 2) are denoted by the same reference numerals. In embodiment 2, the operation of determining the connection state of the individual electrodes described in detail below is performed before the actual measurement operation of the sample, and the operation is similar to that in embodiment 1.

The difference from embodiment 1 is that, in terms of the circuit, switches 33 and 34 are provided between the electrode portion 10 and the ground, and the positive dc power supply 35 and the ground are switched. Note that the switch 28 of the receiving unit 24 in embodiment 1 (fig. 2) is eliminated, and instead, a switch 32 is disposed between the capacitor 23 of the rectifier circuit unit 21 and the ground. Further, for the positive dc power supply 35, a positive potential (+4 volts) much higher than the electromotive force of each ion selective electrode is used.

In the example shown in fig. 3, switches 33 and 34 connected in parallel and in series are provided between the liquid ground electrode (LG) and the ground of the electrode portion 10. The switch 33 is grounded via a positive dc power supply 35.

(description of measurement sequence)

First, the diluent is supplied to the electrode portion to fill the flow path 56 of the electrode portion 10. Then, the switch 32 in the signal input circuit 31 is turned off to disconnect the capacitor 23 from the ground. At the same time, the switch 34 connected to the electrode portion 10 is opened to disconnect the connection to the ground. Then, the switch 33 is turned on to connect the positive dc power supply 35.

In this circuit state, the voltage (+4 volts) of the dc power supply 35 is divided by the resistance in the vicinity of the electrode portion 10 and the resistance 22, and most of the voltage is applied to the resistance 22 under the condition of embodiment 2. Therefore, the voltage of the positive dc power supply 35 applied to each electrode portion reaches the signal input circuit 31 through the electrode portion 10, and is measured as the output of the operational amplifier 25 by the signal processing circuit 14 via the wiring portion 13.

Therefore, if the measurement result in the signal processing circuit 14 is equal to or greater than a predetermined value (for example, about +3 volts) predetermined as a threshold value corresponding to the voltage (+4 volts) of the dc power supply 35, it can be determined that the connection of the electrode portion 10 is normal. Conversely, if the measurement result in the signal processing circuit 14 is less than the predetermined value, it can be determined that no circuit is formed from the positive dc power supply 35 to the signal processing circuit 14, and the connection state of the electrode portion 10 can be determined as abnormal.

After the measurement, it is preferable to return to the normal measurement mode in order to minimize the risk of applying an excessive external voltage to the electrode portion 10 by quickly returning the switches 32, 33, and 34 to their original states. The operation of disconnecting the capacitor 23 from the ground by opening the switch 32 is performed to suppress a current flowing through the electrode portion 10 due to the application of the voltage (+4 volts) of the dc power supply 35.

According to the embodiments described above, the electrolyte measurement device can detect an abnormality in the connection state of each electrode of the electrode portions, such as disconnection or disconnection of the plugs of the ion selective electrode, the comparative electrode, and the liquid ground electrode, without adding a dedicated detection device.

Further, it is not necessary to actually measure the concentration of ions using a standard solution having a known ion concentration. Further, since the connection state can be easily confirmed before the actual measurement by the electrolyte measuring device is started, the sample measurement can be always performed in a normal state after the connection state is confirmed.

In addition, in order to detect the residual potential of each electrode of the electrode section, the connection state can be effectively determined not only for the ion selective electrode but also for the comparative electrode, which has a feature that has not been obtained in the conventional art. Further, according to embodiments 1 and 2, there is no need to use a standard solution or the like having a known ion concentration, and such a feature can be easily performed.

Further, according to the above embodiments, it is possible to detect abnormalities in the connection state of the electrode portion such as disconnection or disconnection of the electrode cable of the ion selective electrode or the comparative electrode or the liquid ground cable, without adding a dedicated detection device, and without depending on the state of the measurement layer. Further, it is not necessary to actually measure the concentration of ions using a standard solution having a known ion concentration. Further, since the confirmation can be easily performed before the start of the actual measurement, the sample measurement can be always performed in a normal state thereafter.

Further, according to each of the above embodiments, since an extra sensor or the like for monitoring the connection state of the electrodes is not required, it is possible to easily retrofit an existing electrolyte measurement device, and it is possible to improve the performance of the device at low cost.

Industrial applicability

The present invention is suitably used for an analysis device for medical use using an ion selective electrode for the purpose of measuring the concentration of electrolyte ions dissolved in a biological fluid such as blood or urine.

Description of the symbols

1 electrolyte measuring apparatus

10 electrode part

11. 31 signal input circuit

12 differential amplifier unit

13 wiring part

14 signal processing circuit

15 differential amplifier circuit

21 rectifier circuit part

22 resistance

23 capacitor

24 receiving part

25 operational amplifier

26. 35 positive DC power supply

27 high resistance element

28. 32, 33, 34 switch

29 negative dc power supply.