JP2003262613A - Apparatus for automatically measuring concentration of ion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic ion concentration measuring apparatus capable of accurately and easily measuring the concentration of ions of a large number of samples. <P>SOLUTION: The automatic ion concentration measuring apparatus comprises: a flow-type ion concentration sensor 2a; a reference liquid container 3; a cleaning liquid container 4; a sample container 5 for housing the liquid samples to be measured S; a liquid feeding mechanism 6 for feeding the liquids in such a way that each liquid flows through the ion concentration sensor 2a; a waste liquid container 7 for housing waste liquids after they have flowed through the ion concentration sensor 2a; and a control part 8 for performing a series of measuring procedures S1-S17 for measuring the concentration of ions of the samples to be measured S through the use of the ion concentration sensor 2a after measurement preparations of the ion concentration sensor 2a are made by the control of the feeding mechanism 6. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic ion concentration measuring device, and more particularly, to calibration using a standard solution in an ion concentration measuring device, cleaning with a cleaning liquid, and measurement of a sample to be measured. The present invention relates to an automatic ion concentration measuring device that can be fully automated.

[0002]

2. Description of the Related Art Conventionally, an ion concentration measuring instrument using a glass electrode 31 has been used for measuring ions such as pH. FIG. 7 is a diagram for explaining a conventional pH measuring method using the glass electrode 31.

In FIG. 7A, the glass electrode 31 is washed with the cleaning liquid 3
2 shows a procedure of immersing the glass electrode 31 in a container 33 in which the first standard solution 34 is housed and immersing the glass electrode 31 in a container 35 in which the first standard solution 34 is housed. Liquid 3
4 shows a procedure for measuring pH of 4. FIG. 7C shows
The procedure for cleaning the glass electrode 31 after measurement by spraying the cleaning liquid 32 is shown. FIG. 7D shows the glass electrode 31.
The second standard solution 36 in a container 37 containing the second standard solution 36
The procedure for measuring the pH of the standard solution 36 is shown.

That is, in the above-mentioned conventional example, two pH values are used.
2 using the first standard solution 34 and the second standard solution 36 having a value
The glass electrode 31 can be calibrated at two points by performing calibration once and measuring the pH values of the two standard solutions 34 and 36 using the glass electrode 31, respectively.
Further, it is necessary to wash the glass electrode 31 with the washing solution 32 so that the first standard solution 34 does not mix with the second standard solution 36 during the measurement of the standard solutions 34 and 36.

FIG. 8 is a diagram showing an example of measuring the pH of a sample S to be measured using a conventional ion concentration measuring device. Figure 8
8A shows a procedure for preparing the sample container 38 for containing the measurement target sample S in an appropriate container, and FIG. 8B shows a procedure for cleaning the glass electrode 31.
(C) shows a procedure of immersing the glass electrode 31 in the container 38 and measuring the pH of the sample S to be measured.

The glass electrode 31 shown in FIG.
It is possible to measure the pH of the measurement target sample S more accurately by calibrating with 4, 36 and sufficiently washing with the washing liquid 32.

Incidentally, the glass electrode 31 using the cleaning liquid 32
7C, even if the glass electrode 31 is immersed in the cleaning liquid 32 housed in the container 33 as shown in FIG. 7A, the cleaning is performed as shown in FIGS. 7C and 8B. As described above, the cleaning liquid 32 may be sprayed and then wiped off by an operator.

[0008]

However, when the conventional ion concentration measuring instrument is used, the standard solution 34,
36 and the sample container 38 need not be prepared, and the user of the apparatus can perform complicated measurement procedures such as washing the electrode 31 of the ion concentration measuring instrument in order to measure the pH of one measurement target sample S. If we did not do it ourselves, we would not be able to make accurate measurements.

Further, if the above measurement procedure is not performed correctly, it may cause an error in the measured value.
The difference in the measurement procedure caused by the difference in the user of the device may cause the variation in the measured value as it is, and the measured value may become unstable.

Therefore, the inventors of the present invention have devised an automatic calibration device for a laboratory ion concentration meter which automatically calibrates an ion concentration meter such as the above-mentioned ion concentration meter according to a fixed procedure, and received a utility model registration. Yes (utility model registration No. 259
No. 9994). However, in the case of measuring a large number of measurement target samples, it is not only troublesome to measure the measurement target sample after performing calibration by using the automatic calibration device of the laboratory ion concentration meter, and it takes a long time for measurement. It was also the reason why it took time.

The present invention has been made in consideration of the above-mentioned matters, and an object thereof is to provide an automatic ion concentration measuring apparatus which enables accurate and simple measurement of the ion concentration of a large number of samples. Especially.

[0012]

In the automatic ion concentration measuring device according to the first aspect of the present invention, the flow path formed by facing the ion concentration sensor inside has a standard solution sending flow path, a cleaning solution sending flow path or It is characterized in that it is configured so that it can be selectively communicated with the measurement target sample liquid supply flow path, and that it is communicated with the waste liquid portion downstream thereof.

That is, by using the automatic ion concentration measuring device of the present invention, the user of the device can switch the standard liquid, the cleaning liquid or the liquid of the sample to be measured to the ion concentration sensor and send the liquid. As a result, not only the series of steps necessary for measuring the ion concentration but also the series of steps from the preparation of the ion concentration sensor to the measurement
This can be easily performed by switching the respective flow paths.

When the liquid detection sensor is provided in the flow path facing the ion concentration sensor, the supply status of each liquid to the ion concentration sensor can be confirmed, and the reliability is improved.

The automatic ion concentration measuring device of the second invention is a flow type ion concentration sensor, a standard liquid container, a cleaning liquid container, a sample container for accommodating a sample to be measured which is a liquid, and an ion concentration of each liquid. A liquid feeding mechanism that feeds so as to flow to the sensor, a waste liquid container that stores the waste liquid that has flowed to the ion concentration sensor, and a measurement target sample after the measurement preparation of the ion concentration sensor is performed by the control of the liquid feeding mechanism. And a control unit that executes a series of measurement procedures for measuring the ion concentration using the ion concentration sensor.

That is, the user of the apparatus uses the automatic ion concentration measuring apparatus of the present invention to perform the measurement preparation of the ion concentration sensor such as the cleaning work and the calibration work of the ion concentration sensor using the standard solution and the cleaning solution. A series of measurement procedures for measuring the ion concentration of the sample to be measured can be automatically performed by the control of the liquid feeding mechanism by the control unit, and the calibration from the ion concentration sensor to the measurement can be achieved completely automatically.

Therefore, the user of the apparatus simply puts the sample to be measured in the sample container and gives a command to the control unit by button input or the like, and a series of measurement procedures are performed automatically without any special operation. it can. Further, as in the conventional case, the container 3 for containing the standard solution, the cleaning solution and the sample to be measured
There is no need to prepare 3, 35, 37 and 38, and the labor required for measurement can be reduced accordingly.

Since the above-mentioned series of measurement procedures are carried out under uniform control by the control section, by always carrying out a constant procedure, reproducibility is good and there is no variation depending on the skill of the device user. Not able to make accurate measurements. Furthermore, the ion concentration sensor is regularly calibrated by the control of the controller even if the device user does not have to be aware of it. Therefore, the reliability of the measured value can be improved without the device user's trouble. it can. That is, even if the number of measurement target samples is large, the ion concentration of each measurement target sample can be easily and accurately measured.

When the standard solution container and the cleaning solution container have a replaceable cartridge structure, a calibration solution container,
The daily measurement can be always put into the optimum state by a simple exchange operation in which the cleaning liquid container is exchanged at regular intervals.

When the ion concentration sensor has a replaceable cartridge structure, even if the ion concentration sensor is deteriorated, it can be dealt with by a simple replacement work. This can be easily dealt with by performing maintenance by simply replacing the cartridge of the ion concentration sensor periodically.

When the liquid feeding mechanism is connected to the sample container and has a pump capable of measuring the ion concentration of the sample to be measured while flowing the sample to be measured, the ion concentration of the sample to be measured can be continuously measured or It is possible to measure changes over time.

When the liquid sending mechanism has a liquid detection sensor for detecting the supply status of the standard solution or the sample to be measured to the ion concentration sensor, the supply status of the standard solution or the sample to be measured to the ion concentration sensor is confirmed. However, since the ion concentration sensor can be calibrated or the ion concentration of the sample to be measured can be measured, more accurate and highly reliable measurement can be performed.

The preparation for measurement of the ion concentration sensor is the first cleaning procedure for supplying the cleaning liquid from the cleaning liquid container to the ion concentration sensor, and the detection of the ion concentration sensor in the state where the standard liquid is supplied from the standard liquid container to the ion concentration sensor. If the calibration procedure for calibrating the ion concentration sensor using the values and the second cleaning procedure for supplying the cleaning liquid from the cleaning liquid container to the ion concentration sensor again are performed, the ion concentration sensor should be calibrated for each measurement. Since it can be performed, the reliability of the measurement accuracy can be improved.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining the overall configuration of a first embodiment of an automatic ion concentration measuring device 1 of the present invention.
The following description shows an example of measuring pH as an example of ion concentration. Therefore, in the following description, the automatic ion concentration measuring device 1 will be described as an automatic pH measuring device, but the present invention is not limited to pH measurement.

In FIG. 1, 2 is a flow-type pH sensor 2
a is a sensor block having a replaceable cartridge structure, 3 is a standard solution container, 4 is a cleaning solution container, 5 is a sample container for containing a measurement target sample S which is a liquid, and 6 are containers 3 to 5 respectively.
Is switched to communicate with the sensor block 2 so that each liquid is circulated to the pH sensor 2a, and 7 is an example of a waste liquid container, which is a waste liquid container for storing the waste liquid after flowing through the pH sensor 2, 8 (FIG. (Only shown) is a control unit that executes a series of measurement procedures for measuring the pH of the sample S to be measured using the pH sensor 2a after preparing the measurement of the pH sensor 2a by controlling the liquid feeding mechanism 6. Is.

FIG. 2 is a diagram showing an example of the structure of the sensor block 2 having a flow-through type pH sensor 2a.
Is a tube made of, for example, pH-responsive glass, 10 is an internal liquid filling portion formed around the tube 9, 11
Is an internal electrode provided in the internal liquid filling portion 10, 12 is a reference electrode, and 13 is a temperature compensation electrode. That is, the pH sensor 2a of the present example uses the response glass and the sensor flow path Fs.
By forming the main part of the standard liquid Sa, S
The pH of b, Sc or the sample S to be measured can be measured.

2b and 2c are standard solutions Sa and S on the upstream side and the downstream side of the sensor block 2 using light.
b, Sc, or a liquid detection sensor formed so as to confirm the presence of a sample to be measured. Therefore, it is possible to detect that the sensor block 2 is filled with the liquid by detecting the liquid with both the liquid detection sensors 2b and 2c. The present invention is not limited to the configuration of the sensor block 2. That is, the pH sensor 2a
May have a configuration using a general glass electrode or may be an ion concentration sensor other than the glass electrode (for example, an electrode using ISFET).

Further, in FIG. 2, the reference electrode 12 and the temperature compensation electrode 13 have a general electrode configuration, but it is desirable that the reference electrode 12 and the temperature compensation electrode 13 are also flow type electrodes. Needless to say.

In any case, the sensor block 2
The pH sensor 2a can be easily maintained by using a removable cartridge structure, that is, by configuring the sensor block 2 so that it can be attached to and detached from other components and is connected and connected when mounted. Further, even when the characteristics of the pH sensor 2a are deteriorated, the sensor block 2 can be replaced with a new pH sensor 2a very easily and quickly.

The standard solution container 3 comprises standard solution containers 3a, 3b and 3c for containing standard solutions Sa, Sb and Sc having pHs of 7.0, 4.0 and 9.0, respectively. That is,
The automatic pH measuring device 1 of the present invention can perform more accurate calibration by calibrating the pH sensor 2a at three points. In addition, in the following description, three standard solutions Sa,
An example using Sb and Sc will be described, but the present invention does not limit the number and type of standard solutions. The standard solution containers 3a, 3b, 3c and the cleaning solution container 4 each have an air hole A formed therein to improve the flow of the standard solution Sa, Sb, Sc or the cleaning solution.

Further, each of the containers 3 and 4 has a replaceable cartridge structure, that is, a structure which is detachable and communicatively connectable to a switching valve 14 which will be described later. Replenishment can be done quickly by replacing the cartridge. The sample container 5 is opened, for example, by forming a funnel-shaped opening 5a at the upper end thereof, and the sample S to be measured can be easily accommodated therein.

The liquid feeding mechanism 6 in this embodiment is connected to the respective containers 3, 4 and 5 and is connected to the upstream side of the sensor block 2 so as to be directly connected to the switching valve 14 and the sensor block. It has a three-way valve 15 connected to the downstream side of 2 and a pump (hereinafter referred to as a syringe pump) 16 using a syringe integrally connected to the three-way valve 15. In addition, this syringe pump 1
6 has a syringe 16a and an actuator 16b for driving the syringe 16a.

That is, by the control from the control unit 8,
The standard liquids Sa, Sb, S using the switching valve 14
In a state in which any one of c, the cleaning liquid, and the sample S to be measured is selected, the three-way valve 15 is controlled to connect the syringe pump 16 to the sensor block 2 so that the syringe pump 16 is driven to increase the volume in the syringe 16a. Switching valve 14
The liquid selected by is drawn into the sensor block 2,
It can be distributed.

In addition, in the switching valve 14 of this embodiment, the standard liquid feed passages Fa, Fb, Fc, the washing liquid feed passage Fd or the measurement target sample feed passage Fe are formed and these passages are formed. Fa to Fe are selectively selected by this switching valve 14 so that they can communicate with the sensor flow path Fs facing the pH sensor 2a. That is, in this example, each of the flow paths Fa through the internal flow path Ff formed in the switching valve 14 is selected by the switching valve 14.
Fe and the sensor channel Fs are selectively communicated with each other. Further, the volume of the internal flow path Ff is configured to be as small as possible. In addition, the switching valve 14 and the sensor block 2 are directly connected to each other, thereby eliminating an extra flow passage therebetween.

Further, the three-way valve 15 is switched to change the syringe 1
6a is connected to the waste liquid container 7, and the syringe 16
The liquid drawn into the syringe 16a can be discharged to the waste liquid container 7 by driving so as to reduce the volume in a.

The waste liquid container 7 has the same cartridge structure as that of the standard liquid container 3 and the cleaning liquid container 4 described above. Therefore, the waste liquid can be disposed of by removing the cartridge of the waste liquid portion 7. However, the waste liquid portion is not limited to the waste liquid container 7 having the cartridge structure. It is also possible to form a waste liquid flow path as a waste liquid portion and discard this waste liquid as it is, depending on the type and concentration of the ions to be handled.

The control unit 8 has an input / output unit 17, which has a display unit 17a and, for example, two input keys (measurement keys) 17b and 17c. In addition, the control unit 8 controls the respective units 14 to 16 to measure the sample S to be measured, the standard solutions Sa, Sb, Sc, and the like.
A liquid sending program Pf that executes a liquid sending process for controlling the flow of an arbitrary liquid (hereinafter, simply referred to as a solution) of the cleaning liquid, and controls the liquid sending mechanism 6 by appropriately calling the liquid sending program Pf. And a measurement program Pd for measuring pH using the sensor block 2.

By executing the liquid delivery program Pf, the valves 14 and 15 and the syringe pump 16 are arbitrarily controlled to select the arbitrary solution and supply the selected solution to the sensor block 2. In addition,
The solution in the sensor block 2 can be appropriately sucked out and stored in the waste liquid container 7. Further, in each liquid feeding operation, it is confirmed by the detection signals from the liquid detection sensors 2b and 2c that the solution surely fills the inside of the sensor block 2.

The liquid supply control that can be performed by controlling the valves 14 and 15 and the syringe pump 16 by executing the liquid supply program Pf is not limited to the supply and suction of each solution to the sensor block 2 described above.

That is, for example, with the sample container 5 open to the atmosphere by the switching valve 14 selected,
The three-way valve 15 is switched so as to connect the sensor block 2 and the syringe 16a to each other so as to suck the sample S to be measured using the syringe pump 16, and the three-way valve 15 is switched so as to connect the waste liquid container 7 and the syringe 16a to each other. By repeatedly performing the operation of discharging the sample S to be measured using the syringe pump 16 of the sensor block 2
It can be controlled to drain all the solution inside.

Further, for example, in a state where the cleaning liquid container 4 is selected by the switching valve 14, the three-way valve 15 is switched so as to connect the sensor block 2 and the syringe 16a to each other, and the cleaning liquid is sucked by using the syringe pump 16. Select the sample container 5 by the switching valve 14,
By performing an operation of discharging the cleaning liquid using the syringe pump 16, it is possible to feed the cleaning liquid into the sample container 5 to clean it.

In the automatic pH measuring apparatus 1 of this embodiment, the sensor block 2 is directly connected to the switching valve 14 so that a wasteful space such as piping is provided between the switching valve 14 and the sensor block 2. Since there is no such solution, it is possible to supply the minimum necessary amount of solution to the sensor block 2 without wasting the above solution. In other words, by reducing the amount of solution used in one calibration,
It is possible to increase the number of times the volume of each container 3, 4 can be calibrated.

Furthermore, since the amount of the sample S to be measured required for measurement can be reduced, it is useful when a large amount of sample S to be measured cannot be collected. In this case, as shown in FIG. 1, the distance between the sample container 5 and the sensor block 2 may be minimized to minimize the volume in the flow path generated between the sample container 5 and the sensor block 2. desirable.

In order to reduce the consumption of each solution,
By using the detection signals from the liquid detection sensors 2b and 2c, the suction of the solution using the syringe pump 16 is stopped when the sensor block 2 is filled with the solution, or the suction is performed for a predetermined short time from this point. It is also possible to program to consume the minimum required solution by turning off. Further, when the syringe pump 16 is used for the liquid feeding mechanism 6 as in this example, it is also possible to accurately control the amount of the solution to be additionally sucked after the time point.

As in this example, the liquid detection sensor 2b,
By providing 2c on the upstream side and the downstream side of the sensor block 2 respectively, reliable control is possible, but it goes without saying that only one of the liquid detection sensors may be provided.

In addition, it goes without saying that in order to reduce the amount of solution consumed, it is desirable to make the volume formed in the internal flow passage in the switching valve 14 as small as possible.

FIG. 3 is a diagram showing an example of the operation of the measurement program Pd. The operation described in FIG. 3 is performed by the pH sensor 2a of the two measuring keys 17b and 17c.
7 shows a series of operations when the measurement key 17b for measuring the pH of the sample S to be measured is pressed after the calibration is performed. The other measurement key 17c is a measurement key for performing pH measurement of the measurement target sample S without performing calibration. By using the measurement key 17c, execution of the calibration work can be selected, and consumption of the standard solutions Sa to Sc and the cleaning solution necessary for the calibration can be suppressed.

In FIG. 3, S1 is a step of supplying the cleaning liquid to the sensor block 2 and then discharging the cleaning liquid (first cleaning procedure for supplying the cleaning liquid from the cleaning liquid container 4 to the pH sensor 2a). That is, when the device user presses the measurement key 17b, the automatic pH measuring device 1 first cleans the pH sensor 2a using the cleaning liquid.

S2 is a step of supplying the standard solution Sa having a pH of 7.0, for example, to the sensor block 2. Here, it is desirable that the standard liquid Sa supplied to the sensor block 2 is supplied in an excess amount so that the cleaning liquid that may remain in the sensor block 2 can be washed away. Also,
The supply status of the standard liquid Sa to the sensor block 2 is confirmed by the liquid detection sensors 2b and 2c.

S3 is a standard solution Sa using the pH sensor 2a.
PH measurement is performed to calibrate the pH sensor 2a (from the standard solution container 3a to the standard solution Sa.
Is a calibration procedure for calibrating the pH sensor 2a by using the detection value of the pH sensor 2a in the state of supplying. At this time, while performing the pH measurement and calibration using the standard solution Sa, for example, both the switching valve 14 and the three-way valve 15 can be closed to suppress the consumption of the standard solution Sa.

Step S4 is a step of withdrawing the standard solution Sa from the sensor block 2 and discharging it. here,
For example, when the switching valve 14 has a switching flow path (not shown) that allows the sensor block 2 to communicate with the outside air, the switching of the switching valve 14 controls the outside air to flow into the sensor block 2 so that the standard liquid Sa is supplied. It can be completely removed from the sensor block 2. Alternatively, in the calibration stage of the pH sensor 2a, the sample S to be measured may not be put in the sample container 5, and the outside air may be drawn from the open end side 5a of the sample container 5.

Further, the fact that the standard liquid Sa in the pH sensor 2a has been completely discharged means that the liquid detection sensors 2b and 2c have been discharged.
Can be confirmed by. However, it goes without saying that the standard solution Sa can be discharged with the supply of the next solution.

The subsequent steps S5 to S8 and S9 to S12 are basically the same steps as the steps S1 to S4.
That is, S5 is a step of supplying the cleaning solution and then discharging it, S6 is a step of supplying the standard solution Sb having a pH of 4.0, S7 is a step of performing calibration using the standard solution Sb, and S8 is a standard solution Sb. Is a step of discharging.
Further, S9 is a step of supplying the cleaning solution and then discharging it, S10 is a step of supplying the standard solution Sc having a pH of 9.0, S11 is a step of performing calibration using the standard solution Sc, and S12 is a standard solution Sc. Is a step of discharging.

By the series of steps S1 to S12, the pH sensor 2a is calibrated at three points to
After the sensor 2a is prepared for measurement, the pH sensor 2a can be fully and automatically calibrated in preparation for the subsequent measurement of the sample S to be measured. However, in the case of continuously measuring a plurality of measurement target samples S, by pressing the measurement key 17c, these steps S1 to S1 are performed.
It is also possible to omit the process of 2.

The calibration procedure of the pH sensor 2a described above shows an example of the present invention, but the present invention is not limited to this procedure. That is, in this example, the cleaning liquid is supplied to the sensor block 2 in steps S1, S5 and S9.
The pH sensor 2a is cleaned by supplying and discharging the standard solution Sa, Sb, Sc to the next steps S2, S6, S10 instead of supplying the cleaning solution.
It is also possible to perform cleaning by supplying and discharging. Further, the steps S1, S5 and S9 are omitted, and the standard solution S of the next steps S2, S6 and S10 is omitted.
When supplying a, Sb, Sc, a little extra standard solution S
By supplying and discharging a, Sb, and Sc, it is possible to replace the cleaning step.

S13 is a step of supplying the cleaning liquid to the sensor block 2 and then discharging the cleaning liquid (cleaning liquid container 4
Is a second cleaning procedure for supplying a cleaning liquid from the pH sensor 2a to the pH sensor 2a. That is, the condition of the pH sensor 2a is prepared for the next pH measurement of the measurement target sample S.

S14 is a step of supplying the sample S to be measured to the sensor block 2. Even in this case, it is desirable that the amount of the sample S to be measured supplied to the sensor block 2 be supplied in a slightly excess amount so that the cleaning liquid that may remain in the sensor block 2 can be washed away. The supply status of the measurement target sample S to the sensor block 2 is confirmed by the liquid detection sensors 2b and 2c,
When the amount of the sample S to be measured is small, a message indicating that measurement is impossible is displayed on the display unit 17a, or an error is notified by an alarm or the like.

Since the pH sensor 2a of the automatic pH measuring apparatus 1 of the present invention is a flow-type pH sensor, the amount of the sample S to be measured required for the measurement is relatively small, and the sample container 5 to the sensor block is used. Since the sample container 5, the switching valve 14 and the block sensor 2 are brought into close contact with each other to eliminate the extra flow passage so that the volume in the flow passage between the two can be made as small as possible, the measurement required for the measurement can be performed. The amount of the target sample S becomes as small as possible.

Further, since the pH sensor 2a of this example uses the response glass tube 9, it is possible to measure an extremely small amount of the sample S to be measured. In addition, when the cleaning liquid is discharged in step S13, the external air is controlled to be sucked into the sensor block 2 through the sample container 5 to reliably discharge the cleaning liquid, and thus the extra supply is supplied in step S14. The amount of the target sample S can be reduced. In this case, immediately before the control unit 8 performs the process of step S14, it is possible to display a message prompting the user of the device to insert the sample S to be measured or give an alarm notification.

S15 is a step of measuring the pH of the sample S to be measured using the pH sensor 2a (from the sample container 5 to p
The pH of the measurement target sample S is calculated by using the detection value of the pH sensor 2a in the state where the measurement target sample S is supplied to the H sensor 2a.
Is a measurement procedure for obtaining.

The automatic pH measuring device 1 of the present example has a step S
At the time of pH measurement at 15, the switching valve 14 and the three-way valve 15 are fully closed to stop the flow in the pH sensor 2a portion, thereby performing more stable pH measurement. Therefore, in S16, a step of discharging the sample S to be measured is provided.

However, the pH measurement in step S15 can be performed while the sample S to be measured is drawn by the syringe pump 16. That is, the syringe 16a that constitutes the liquid delivery mechanism 6 of the present example is connected to the material container 5 so that the pH of the syringe 16a is maintained while the sample S to be measured flows.
May be measured.

S17 is a step of supplying a cleaning liquid for cleaning the pH sensor 2a after the measurement and discharging the cleaning liquid.

Since the above steps S1 to S17 are fully automatically executed by the measurement program Pd executed by the control unit 8, the apparatus user has a complicated pH.
It is not necessary to perform the calibration process of the sensor 2a by itself, and the calibration to the measurement can be completed by one-touch operation. Further, since the calibration procedure is performed by a uniform process that is sequence-controlled by the measurement program Pd,
Accurate measurements can be made at any time, independent of the skill of the device user.

Further, in the above example, since the pH sensor 2a is calibrated at three points, it is possible to calibrate the deviation of the characteristics more accurately. However, the pH sensor 2a is calibrated by the measurement program Pd. It is also possible to control 2a to perform two-point calibration or one-point calibration. vice versa,
You may calibrate four or more points.

Further, in this example, the measurement program Pd executes the calibration process in each measurement to maximize the reliability of the measured value, but it is programmed to perform the calibration process intermittently. May be.
That is, three-point calibration is performed at relatively long predetermined intervals (once every several tens of measurements, every few days, etc.), or at relatively short predetermined intervals (once every several measurements or several hours). Various modifications are conceivable, such as performing one-point calibration once every 1 time). In any case, the user of the apparatus performs the calibration process on the automatic pH measuring device 1.
By doing so, it is possible to eliminate the labor required when operating the automatic pH measuring device 1.

In addition, in the automatic pH measuring device 1 of this example, the standard liquid container 3, the cleaning liquid container 4 and the waste liquid container 7 are containers of removable cartridge structure. Therefore, the automatic pH measuring device 1 periodically adjusts each container 3,
By replacing the cartridges 4 and 7, the device user does not need to perform any maintenance of the automatic pH measuring device 1.

Also, the sensor block 2 can be easily replaced by fitting the sensor block 2 between the switching valve 14 and the three-way valve 15 so as to communicate with each other. Therefore, even when the characteristics of the pH sensor 2a are deteriorated to the extent that they cannot be compensated for by the above-described calibration, it is possible to deal with this relatively easily.

The present invention is not limited to the configuration of the automatic pH measuring device 1 described above. 4 and 5 are views showing the overall configuration of the automatic pH measuring device 1'of the second embodiment. In FIGS. 4 and 5, the parts denoted by the same reference numerals as those in FIGS. 1 to 3 are the same or equivalent parts, and thus detailed description thereof will be omitted.

The liquid feed mechanism 6 in this embodiment includes a pump 18 as a power source, a switching valve 14, a sensor block 2,
It has a pump 18 and a flow path 19 which connects and connects the waste liquid container 7 in this order. That is, the solution (any one of the sample S to be measured, the standard solution, and the cleaning solution) switched by the switching valve 14 is guided into the sensor block 2 by the suction force of the pump 18, and is further discarded in the waste liquid container 7.

In addition, the sensor block 2 of this example includes a pH sensor 2d, which is, for example, an ISFET.
It is formed so as to face the inner flow path 19, and a comparison liquid flow-through type comparison electrode 2e is provided on the downstream side thereof. By providing a sensor using an ISFET as the pH sensor 2d as in this example, it is possible to measure a very small amount of the sample S to be measured with high accuracy. Further, the consumption of the standard solution and the cleaning solution can be suppressed.

In addition, the suction by the pump 18 can be always performed at a constant speed, and the change in pH can be measured while flowing the sample S to be measured contained in the sample container 5 at a predetermined flow rate. It is possible.

Further, as shown in the perspective view of FIG. 5, the sample container 5 is open to the hole formed on the upper surface of the automatic pH measuring device 1'to facilitate the accommodation of the sample S to be measured. In other words, the user of the apparatus simply presses the measurement keys 17b and 17c formed on the same surface, and at the same time, inserts the sample S to be measured from the open end 5a formed on this surface to form the sample on this surface. The measurement result can be displayed on the display unit 17a.

FIG. 6 is a view for explaining a further modified example of the liquid feeding mechanism and the pH sensor. 1 to 6 in FIG.
Since the parts denoted by the same reference numerals as 5 are the same or equivalent parts, detailed description thereof will be omitted.

In FIG. 6, 2f is a pH sensor consisting of a cylindrical glass electrode, 20 is a container for containing the pH sensor 2f, and 21 is the outside air inside the container 20 with the pH sensor 2f housed therein. It is a packing to shut off from. Reference numeral 22 is a pipe for connecting and connecting the switching valve 14 and the inside of the container 20, and 23 is a pipe for connecting and connecting the inside of the container 20 and the syringe 16a.

Therefore, in the liquid feeding mechanism 6 of this example, the switching valve 14, the container 20 and the syringe pump 16 are connected to the pipe 2.
2, 23 are connected in this order. Therefore, each of the valve bodies 14a to 14 constituting the switching valve 14
One of the solutions (measurement target sample S, standard solution) by driving the syringe pump 16 so as to increase the volume inside the syringe 16a with one of the valves d opened and the valve body 14e closed. (Sa, Sb, cleaning liquid) can be selectively sucked and introduced into the container 20.

Next, by closing all the valve bodies 14a to 14d and opening the valve body 14e, the syringe pump 16 is driven so as to reduce the volume in the syringe 16a, so that the solution located in the container 20 is removed. All can be discharged into the waste liquid container 7. By configuring the liquid feeding mechanism 6 as in this example, the sensitive portion of the pH sensor 2f formed of a general glass electrode arranged in the container 20 can be immersed in an arbitrary solution. The pH sensor 2f has a replaceable cartridge structure.

Further, the pipe 23 is provided in the liquid feeding mechanism 6.
Various modifications are conceivable, such as providing the waste liquid container 7 on the top. In any case, the liquid feeding mechanism 6 includes a pump 16 and a switching control of the switching valve 14 from the control unit 8 (not shown).
Drive control to switch between containers 3, 4 and 5
Connect the H sensor in communication and p the solution in each container 3, 4, 5
It can be distributed to H Sansa.

It is also possible to sequentially measure the pH of a plurality of measurement object samples S ... By attaching an automatic dispensing device for automatically charging a plurality of measurement object samples S ... to the sample container 5. Is.

[0080]

As described above, according to the present invention,
It is possible to fully automatically perform a series of measurement procedures for cleaning the ion concentration sensor, calibrating the ion concentration sensor using a standard solution, and measuring the ion concentration of the sample to be measured by the control unit. The time and effort can be reduced. That is, the apparatus user does not need to prepare a container for storing the standard solution or the sample to be measured and the maintenance of the ion concentration sensor. Further, since the measurement procedure can be performed in a uniform manner, there is no problem such as variation in the value depending on the user of the apparatus.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an automatic ion concentration measuring device according to a first embodiment.

FIG. 2 is an enlarged view showing a main part of the automatic ion concentration measuring device.

FIG. 3 is a diagram illustrating an operation of the automatic ion concentration measuring device.

FIG. 4 is a diagram showing an overall configuration of an automatic ion concentration measuring device according to a second embodiment.

FIG. 5 is a perspective view of the automatic ion concentration measuring device.

FIG. 6 is a view showing a modified example of the automatic ion concentration measuring device.

FIG. 7 is a diagram illustrating a method for calibrating a conventional ion concentration sensor.

FIG. 8 is a diagram illustrating a method for measuring an ion concentration using the ion concentration sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Automatic ion concentration measuring device, 2a ... Ion concentration sensor, 2b, 2c ... Liquid detection sensor, 3 ... Standard liquid container, 4
... Washing liquid container, 5 ... Sample container, 6 ... Liquid sending mechanism, 7 ... Waste liquid container (waste liquid part), 8 ... Control part, 16 ... Pump (syringe pump, 18 ... Pump, Fa to Fc ... Standard liquid sending channel ,
Fd ... washing liquid delivery passage, Fe ... measurement target sample delivery passage,
Fs ... S, a flow path with an ion concentration sensor facing inside
... Sample to be measured, S1 to S17 ... Series of measurement procedure, S
1, S5, S9 ... First cleaning procedure, S3, S7, 11 ...
Calibration procedure, S13 ... Second cleaning procedure, S15 ... Measurement procedure.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G01N 35/08 G01N 27/46 356

Claims (8)

[Claims] 1. A flow path having an ion concentration sensor facing inside can be selectively communicated with a standard solution sending flow path, a cleaning solution sending flow path, or a measurement target sample sending flow path upstream thereof. An automatic ion concentration measuring device, characterized in that it is constructed and communicates with a waste liquid portion downstream thereof. 2. The automatic ion concentration measuring device according to claim 1, wherein a liquid detection sensor is provided in a flow path facing the ion concentration sensor. 3. A flow-through type ion concentration sensor, a standard liquid container, a washing liquid container, a sample container for containing a liquid sample to be measured, and a liquid feed for feeding each of the liquids to the ion concentration sensor. A liquid mechanism, a waste liquid container that stores the waste liquid that has passed through the ion concentration sensor, and an ion concentration sensor that measures the ion concentration of the sample to be measured after the measurement of the ion concentration sensor is performed by controlling the liquid feeding mechanism. An automatic ion concentration measuring device, comprising: a control unit that executes a series of measurement procedures for measurement. 4. The automatic ion concentration measuring device according to claim 3, wherein the standard solution container and the cleaning solution container have a replaceable cartridge structure. 5. The automatic ion concentration measuring device according to claim 3, wherein the ion concentration sensor has a replaceable cartridge structure. 6. The automatic ion concentration measurement according to any one of claims 3 to 5, wherein the liquid feeding mechanism has a pump connected to the sample container so as to measure the ion concentration of the sample to be measured while flowing the sample to be measured. apparatus. 7. The automatic ion concentration measuring device according to claim 3, wherein the liquid feeding mechanism has a liquid detection sensor for detecting the supply status of the standard liquid or the sample to be measured to the ion concentration sensor. 8. The ion concentration sensor is prepared for measurement by first supplying a cleaning liquid from the cleaning liquid container to the ion concentration sensor.
Cleaning procedure, the calibration procedure to calibrate the ion concentration sensor using the detection value of the ion concentration sensor in the state where the standard solution is supplied from the standard solution container, and the cleaning solution from the cleaning solution container to the ion concentration sensor again. The automatic ion concentration measuring device according to any one of claims 3 to 7, which comprises a second cleaning procedure for supplying.