JPS5940260B2 - automatic analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic analyzer that is equipped with an ion-selective electrode and measures the concentration of ions in a sample liquid.

Conventionally, in order to measure the concentration of ions contained in a sample liquid such as sewage, river water, or industrial wastewater, the sample liquid is sampled, a rod-shaped ion-selective electrode, for example, is inserted into it, and the electrode The electrode potential extracted from the electrode was measured.

With this method, analysis operations have to be done manually, and furthermore, while the electrode is inserted into the test liquid, reaction products between ions in the test liquid and the electrode constituent materials may reach the electrode surface. This made cover measurement unstable. On the other hand, there are systems that automate the analysis operations described above, but in those cases, the main method is to automatically feed the sample liquid to be analyzed to the detection element using pumps, transport pipes, valves, etc. It used many expensive metering pumps and precision parts. As a result, the equipment has become expensive and large. The present invention aims to eliminate the above-mentioned conventional drawbacks by simplifying the structure, and embodiments thereof will be described below with reference to the drawings.

FIGS. 1a and 1b show an automatic analyzer which is an embodiment of the present invention.

In the figure, 1 is an insulating base, 2 is a bearing provided on both sides of the base 1, and 3 is an ion-selective electrode for detecting the ion concentration in the sample liquid. To explain the ion-selective electrode here, for example, when the purpose is to detect cadmium ions, the indicator electrode body 4 is made by hot pressing a mixture of silver sulfide and cadmium sulfide powder, which are sensitive substances, and finishing it in a disk shape. In the same way, only the indicator electrode 6 and the silver sulfide powder were constructed by protruding a metal shaft 5 that also functions as a conductive terminal and connected to the element body 4 at the center of one side of the disc. A comparison electrode 8, which also has a shaft 5' protruding from one side of the indicator electrode body T finished in a shape, is bonded with an insulating material 9 interposed therebetween. Note that the shafts 5 and 5' are passed through bearings 2 and supported rotatably. Reference numeral 10 denotes a spring passed through one end of the shaft 5'.
It has the effect of braking the rotation of the shafts 5, 5' by tightening against the spring pressure of the shafts 5, 5'.

13 is a pin that fixes one end of the shaft.

14 and 14' are made of conductive spring plates, and are connected to the base 1, respectively.
It is a contact whose one end is fixed to a support 15 protruding from the shaft 15, and whose other end is pressed against the circumferential surfaces of the shafts 5, 5'.

16 is a lead connected to one end of the contacts 14, 14';
Reference numeral 17 is a guide roller made of, for example, a rubber elastic body and arranged so that its circumferential surface is close to the circumferential surface of the electrode 3. Reference numeral 18 is rotatably supported by the bearing 2 with its shaft.

19 is a gear attached to the shaft 18, 20 is a motor for driving a guide roller, and a gear 21 that meshes with the gear 19 is attached to the end of the shaft.

Here, an example of a tape for supporting a test liquid used in the measurement will be explained using FIGS. 2A and 2B. As shown in the figure, the tape is made of a water-absorbent sheet made of paper, cloth, or foamed resin, which is treated with water-repellent water-repellent material such as silicone resin or vinyl chloride resin at appropriate intervals in the longitudinal direction of the sheet, and then applied to the partition part 22. It is made by forming.
The tape is sent into the test liquid and immersed in the test liquid holding part 23 partitioned by the partition part 22, so that the test liquid is absorbed and supported one frame at a time. Returning to FIG. 1, the operation of the device will be explained.

The sample liquid supporting tape (
When the electrode 3 (indicated by a broken line 24 in the figure) is passed along the direction indicated by the arrow, the electrode 3 is rotated and its peripheral surface comes into contact with the sample liquid carried by the tape. By contacting the test liquid in this way, a potential difference corresponding to the ion concentration in the test liquid is generated between the indicator electrode element 4 and the reference electrode element 7, which causes the shafts 5, 5' and the contact 14, 14', and the lead 16, and the ion concentration is thus measured. Note that when measuring by immersing a rod-shaped ion-selective electrode in the collected sample liquid, as was conventionally done, the electrode surface becomes covered with reaction products over time, which causes Measurements were often unstable. In this device, if there is such a risk, the rotation of the electrode 3 is braked by appropriately tightening the screw 12, so that the circumferential surface of the electrode 3 rotates while slipping on the tape. As a result, the circumferential surface of the electrode 3 is constantly updated, so that measurements are always performed stably. Next, a modification of the structure or arrangement method of the ion selection electrode in the above embodiment will be explained.

FIGS. 3a and 3b show cases in which, for example, the sensitive materials forming the indicator electrode element and the reference electrode element forming the ion-selective electrode have low impedance and high impedance, respectively. When the sensitive material has low impedance, the entire element body is composed of the sensitive material 24 as shown in a. Note that this configuration is the same as in the previous embodiment. On the other hand, when the sensitive substance has high impedance, the central part is made up of a conductive substance 25 (for example, metal), as shown in b, and the sensitive substance 24 is made up around it. FIG. 4 shows various size combinations of ion selective surrounding electrodes and guide rollers and examples of their arrangement. Arrow C in the figure indicates the traveling direction of the test liquid supporting tape passed between the ion selection electrode 26 and the guide roller 27. In this way, by appropriately combining tapes of appropriate sizes, you can control the speed of tape advancement,
Alternatively, the relative speed between the tape and the circumferential surface of the electrode 26 may be controlled to ensure stable measurement. FIGS. 5A and 5B each show an example of the structure of the electrode. Note that a is the same as in the above embodiment, 27 is a guide roller, 28
29 is an ion-selective electrode, 29 is an indicator electrode body, 30 is a reference electrode body, and 31 is an insulating material. In b, an insulating material 31 is also arranged on the outside of each of the indicator electrode element 29 and the comparison electrode element 30 to increase the mechanical strength of these elements 29 and 30. In the figure, 27 and 28 are a guide roller and an ion selection electrode, respectively, as in a.
FIG. 6 shows various examples in which the indicator electrode and the comparison electrode are each made of independent rollers and are arranged so that the circumferential surfaces of the respective electrodes face each other, with different shapes of the electrodes.

In this case, either the indicator electrode element 32 or the comparison electrode element 33 is rotationally driven by the drive system. The tape is passed between the indicator electrode element 32 and the comparison electrode element 33. With this configuration, there is no need to separately provide something such as a guide roller for tape feeding or tape pressure contact, and the structure becomes simpler. Figure 7 shows an example in which the indicator electrode and the reference electrode are each made of independent rollers, and are arranged so that one side of each electrode faces each other and the centers of their axes are located on the same line. Two different types are shown side by side.

As shown in the figure, the sample liquid supporting tape 36 is moved so as to cover the peripheral surfaces of both the indicator electrode element 34 and the comparison electrode element 35. FIG. 8a shows a guide roller 37 containing a permanent magnetic substance, and an insulating material 41 of an ion-selective surrounding electrode 38 arranged so that its circumferential surface faces the guide roller 37.
Also shown is one containing a permanent magnet.

Reference numerals 39 and 40 indicate an indicator electrode element body and a reference electrode element body which are attached to each other via an insulating material 41; 42 and 42' a shaft protruding from the center of each end face of the element bodies 39 and 40;
3 is the axis of the guide roller 37. With such a configuration, by incorporating the electrode 38 into the device so that it can freely rotate and move slightly up and down, the electrode 38 and the guide roller 37 can be moved by the action of the permanent magnetic material contained therein. The tape is attracted to the guide roller 37 side, and as a result, the tape passed between the two is reliably captured and moved. In FIG. 8b, as in FIG. 8a, a tape 44 containing a permanent magnetic substance is moved while being pressed against the circumferential surface of an ion selection electrode 38 whose insulating material 41 contains a permanent magnetic substance. Indicates the condition.

With this configuration, the tape 44 is brought into pressure contact with the circumferential surface of the electrode 38 by itself due to the effect of the permanent magnet material, so that, for example, a guide roller for pressure contact is not required.
As described above, the present invention has a simple structure, and therefore has many advantages such as being small and inexpensive, facilitating continuous automatic measurement, and furthermore, being able to consistently perform measurements stably.

Note that the present invention can be widely applied not only to the measurement of ion concentration but also to the measurement of the conductivity or pH of a solution.

[Brief explanation of the drawing]

FIG. 1a is a cross-sectional view of an automatic analyzer that is an embodiment of the present invention, FIG. 1b is a cross-sectional view of the automatic analyzer including the dashed-dotted line AN in FIG. b is a side view and a plan view of a tape for supporting a sample liquid used in the automatic analyzer, respectively; FIGS. 3A and 3b are views for explaining a modified example of the ion selection electrode to be attached to the automatic analyzer; FIG. 4 is a diagram for explaining a modified example of the combination and arrangement of the electrodes and guide rollers mounted on the automatic analyzer, FIG. 5 A, b, FIG. 6, FIG. 7, FIG. 8 A, b is a diagram for explaining a modified example of the configuration of the electrodes. 1... Base, 3, 26, 28, 38...
・Ion selection electrode, 4, 29, 32, 34, 39...
... Indicator electrode element, 7, 30, 33, 35, 40.
...Reference electrode, 9, 31, 41 ... Insulating material, 5, 5', 42, 427 ... Electrode axis, 1
0... Spring, 14, 14'...
Contactor, 17, 27, 37...Guide roller.

Claims (1)

[Claims] 1. It is characterized by comprising a tape feeding mechanism and a roller-shaped detection body that is rotatably supported and whose peripheral surface contacts the test liquid carried by the tape that has passed through the test liquid. Automatic analyzer. 2. The automatic analyzer according to claim 1, comprising an ion-selective electrode as a detection object. 3. The automatic analyzer according to claim 2, wherein the ion-selective electrode includes an indicator electrode and a reference electrode that are integrated into one via an insulating material. 4. The automatic analysis device according to claim 1, comprising pressure contact means for pressing the tape onto the circumferential surface of the detection object. 5. The automatic analysis device according to claim 4, comprising a rotatable guide roller arranged so that its circumferential surface faces that of the detection object as the pressure contact means. 6. The automatic analyzer according to claim 1, wherein the detection object comes into contact with the tape while slipping.