JPH0321479Y2 - - Google Patents

Description

[Detailed explanation of the idea]

Industrial Application Field This invention relates to a flow cell device used when analyzing a sample liquid using electrodes such as PH electrodes, ion electrodes, metal electrodes, enzyme electrodes, and gas electrodes.
In more detail, it is possible to reliably bring the test liquid to a predetermined set temperature before analysis, which results in high accuracy.
The present invention relates to a flow cell device that can be suitably used when measuring PH. Conventional technology In the past, JIS Z8802, which stipulates PH measurement methods, did not specify standard solutions equivalent to high-precision PH standard solutions, but recently JIS Z8802 for PH standard solutions
has been standardized, and the standard solution corresponding to the high-precision PH standard solution is specified to have repeatability of within ±0.002PH as the average value of three measurements at 25°C ±0.05°C. For this reason, it became necessary to measure the PH of the standard solution more accurately than before, but based on the new JIS standard, high-precision PH measurement with a reproducibility of ±0.002PH was carried out using beaker measurements in accordance with the conventional method. Even if you try to do this, the electrode potential will vary due to the operation of moving the electrode when removing it from the measurement solution and cleaning it, and the difference in the position of the electrode when measuring sequentially, and the response speed will also vary widely. There is a problem in that it is too slow and accurate measurements cannot be made. Therefore, in order to measure pH with high precision, it is necessary to fix the electrode and contact it with the measurement liquid, for example, at the second electrode.
A flow cell system as shown in the figure is suitable. That is, in FIG. 2, a is a flow cell arranged in a constant temperature bath b, and a PH electrode is housed in this flow cell a. In addition, d is a test liquid tank connected to flow cell a, e is a nitrogen gas cylinder connected to test liquid tank d, f is a drainage tank connected to flow cell a via pump g, and h is connected to PH electrode c. This is a PH meter. In the PH measurement system shown in Fig. 2, the test liquid in the test liquid tank d is caused to flow into the flow cell a by the pressure of nitrogen gas in the nitrogen gas cylinder e, and the test liquid is brought into contact with the PH electrode to perform measurement. After the measurement, the test liquid is discharged from the flow cell a to the drain tank f by the operation of the pump g. Problems that the invention aims to solve When accurately measuring the pH of a test liquid using the flow cell method described above, it is necessary to bring the temperature of the test liquid to a predetermined temperature before measuring. , since the test liquid in the test liquid tank d is brought into direct contact with the electrode c in the flow cell a,
It has been difficult to accurately adjust the temperature of the test liquid to a predetermined value. Means for Solving the Problems The present invention has been developed in view of the above circumstances, and involves attaching the lower end of the capped cylindrical lid to the base in a removable and liquid-tight manner, and installing a thermostatic chamber inside the lid. and a cylindrical electrode insertion housing whose upper end extends upwardly through the upper wall of the lid body is located in the thermostatic chamber and provided on a base, and the housing is surrounded within the thermostatic chamber. A spiral tube through which the sample flows is arranged, and the base has a sample introduction port at one end to which the sample introduction tube is connected, and the other end forms a sample introduction hole that communicates with the thermostatic chamber, and one end is connected to the thermostatic chamber. forming a sample guide hole communicating with the housing and having the other end communicating with the inside of the housing; forming a sample discharge hole having one end communicating with the housing and having a sample discharge port connecting the sample discharge tube with the other end; One end of the spiral tube is removably connected to the other end of the sample introduction hole, and the other end of the spiral tube is removably connected to one end of the sample discharge hole to allow constant temperature water to flow through the constant temperature chamber. The sample introduced from the introduction port is introduced into the housing through the sample introduction hole, the spiral tube, and the sample guide hole in order, and after the sample is brought into contact with the electrode inserted into the housing from the upper end side, the sample is passed through the sample discharge hole. By discharging the sample liquid through the sample outlet, the sample liquid can be reliably adjusted to a predetermined temperature and precise analysis can be performed. In other words, in the flow cell device of the present invention, the test liquid is passed through a spiral tube placed in a constant temperature bath, thereby causing heat exchange between the test liquid and constant temperature water, and keeping the test liquid at a predetermined temperature. It is meant to be. Moreover, in this invention, the spiral tube is removably arranged and the spiral tube can be replaced.
A spiral tube having an appropriate diameter and length depending on the introduction speed of the test liquid can be used, and the test liquid can be reliably adjusted to a predetermined temperature. Embodiment FIG. 1 shows a flow cell device according to an embodiment of the present invention, in which 1 indicates a short-axis cylindrical base 2.
This is a cell body having a bottomed cylindrical electrode insertion housing 3 protruding from the top. The electrode insertion housing 3 has a female screw portion 3 screwed on its bottom wall.
It is removably attached to the base 2 by screwing together a male screw portion 2a protruding from the center of the upper wall of the base 2. Further, reference numeral 4 denotes a capped cylindrical lid body, and a constant temperature water inlet 5 and a constant temperature water outlet 6 are formed at the lower end and upper end of the side wall, respectively, and an electrode insertion housing insertion hole 7 is formed at the center of the upper wall. is drilled. This lid body 4 is removable and liquid-tight from the base 2 by screwing a female screw portion 4a screwed on the inner peripheral surface of the lower end into a male screw portion 2b screwed on the outer peripheral surface of the upper end of the base 2. A thermostatic chamber 8 is attached to the thermostatic chamber 8 in which constant temperature water flows between the outer circumferential wall 3 of the electrode insertion housing and the inner circumferential wall of the lid body 4.
is formed. The upper end of the electrode insertion housing 3 passes through the electrode insertion housing insertion hole 7 of the lid 4 and projects above the lid 4. Reference numeral 9 denotes an electrode that is removably inserted into the electrode insertion housing 3 from its upper end opening, and 10 denotes a male threaded portion 3b formed on the outer periphery of the upper end of the housing 3.
An electrode holder 11 is disposed inside the electrode holder 10 and is screwed into the electrode holder 10 to stop the electrode 9 inserted into the housing 3 in a predetermined position and prevent constant temperature water from flowing out from the housing insertion hole 7. This is an O-ring for electrode holding that keeps the space between it and the holding 11 liquid-tight. The base 2 has a sample inlet 12 connected to a sample inlet tube (not shown) provided on the outer peripheral wall of the base 2, and a first sample outlet 13 provided in the thermostatic chamber 8 on the upper wall thereof. A sample introduction hole 14 is formed which communicates with the housing 3 from a first sample inlet 15 provided in the thermostatic chamber 8 on its upper wall to a second sample outlet 16 provided on the bottom wall of the housing 3. A sample guide hole 17 is formed in the housing 3 and communicates with the sample guide hole 3c through a channel hole 3c bored in the housing 3. The first sample outlet 13 and the first sample inlet 15 are connected by a spiral tube 18 disposed in the thermostatic chamber 8 so as to surround the housing 3.
The sample flowing into the sample introduction hole 14 from the sample introduction port 12 passes through the first sample outlet 13, the spiral tube 18,
First sample inlet 15, sample guide hole 17, channel hole 3
c, the sample flows into the housing 3 from the second sample outlet 16. Note that both ends of the spiral tube 18 are connected to the first outlet 13.
and the first inlet 15, respectively, so that the spiral tube is replaceable. Furthermore, the housing 3 is connected to a second sample inlet 20 provided at the upper part of the inner peripheral wall of the housing 3 from a sample discharge port 19 provided on the outer peripheral wall of the base 2 to which a sample discharge pipe (not shown) is connected.
A sample discharge hole 21 is formed which communicates through a flow passage hole 3d bored inside the housing 3, and after the sample that has flowed into the housing 3 comes into contact with the electrode 9, it passes through the second inlet 20 and the flow passage hole 3d. , the sample discharge hole 21, and the sample discharge port 19 in order to be discharged to the outside of the system. When analyzing a test liquid using the above-described flow cell device, first, constant temperature water at a predetermined temperature is introduced into the constant temperature chamber 8 from the constant temperature water inlet 5 and flows out from the constant temperature water outlet 6. Fill with constant temperature water. Next, when the test liquid is introduced into the apparatus from the sample introduction port 12 using a metering pump at an appropriate sampling rate, the test liquid is heat exchanged with the constant temperature water in the constant temperature chamber 8 while flowing through the spiral tube 18. , after reaching a predetermined temperature, the second outlet 16 in the bottom wall of the housing 3
The water flows into the housing 3 from there. In this case, the test liquid is sprayed from the second outlet 16 toward the electrode film 9a at the tip of the upper electrode 9 at a predetermined flow rate, thereby performing the analysis. Thereafter, the test liquid passes through the above-mentioned flow path and is discharged out of the system. According to the above-mentioned flow cell device, the test liquid exchanges heat with the constant temperature water while flowing through the spiral tube 18, and has almost the same temperature as the constant temperature water. Therefore, the test liquid can always be kept at a predetermined temperature before measurement, which improves accuracy. Highly accurate measurements are possible. In addition, since the spiral tube 18 is made removable and the lid 4 is also removable, by removing the lid 4 and replacing the spiral tube, the spiral tube of the appropriate length and diameter can be adjusted according to the sampling speed. can be used. Furthermore, the test liquid is passed from the second outlet 16 to the electrode film 9 at the tip of the electrode 9.
Since the spray is directed toward point a, stable measurement is possible. Next, an experimental example will be shown to specifically explain the effects of the present invention. [Experimental Example 1] A standard thermometer was set in the flow cell device shown in Figure 1, and after setting the constant temperature water temperature to 2500℃, the PH
The standard solution is introduced into the cell at a flow rate of 3 ml/min.
Then, the temperature outside the cell was varied within a range of 25±10°C, and the temperature change inside the cell in this case was investigated. The results are shown in Figure 3. From the results shown in Figure 3, the flow cell device of the present invention has ±
It was recognized that it had excellent temperature characteristics of 0.01°C/outside temperature °C, and it was found that this temperature characteristic completely satisfies the new JIS PH standard liquid standard of ±0.05°C. [Experimental Example 2] Using the flow cell device shown in Figure 1, the standard solution was
Based on JIS standards, regarding standard solutions of PH4 and 7
PH measurement was carried out. In this case, three repeated measurements were performed. Similar experiments were also conducted using a conventional measurement method using a beaker. The results are shown in the table below.

【table】

[Table] From the results in the table, when using the flow cell device of the present invention, the standard value and the measured value match in three repeated measurements for both standard solutions with pH of 4 and 7.
The flow cell device of the present invention was found to be suitable for high-precision PH measurement, and the effectiveness of the present invention was confirmed. On the other hand, in the case of beaker measurement, +0.004 to +0.001PH at PH4, +0.002PH at PH7
A deviation of ~+0.004 occurred, and it was recognized that PH could not be measured with high accuracy depending on the beaker measurement. Effects of the Invention As explained above, the flow cell device according to the present invention, having the above-described configuration, can reliably adjust the temperature of the test liquid to a predetermined temperature, and can be used when precisely analyzing the test liquid, etc. It can be used effectively.

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view showing a flow cell device according to an embodiment of the present invention, Fig. 2 is a schematic diagram showing a measurement mechanism using a conventional flow cell, and Fig. 3 shows the temperature characteristics of the flow cell device of the present invention. This is a graph showing. 2... Base, 3... Electrode insertion housing, 4...
... Cylindrical lid body, 8 ... Constant temperature bath, 9 ... Electrode, 18 ...
...Spiral tube.

Claims (1)

[Scope of utility model registration request] A lower end portion of a capped cylindrical lid body is removably and liquid-tightly attached to a base, a thermostatic chamber is formed within the lid body, and an upper end portion penetrates the upper wall of the lid body and protrudes upward. A cylindrical electrode insertion housing is placed in the thermostatic chamber on a base, and a spiral tube through which the sample flows is disposed in the constant temperature chamber so as to surround the housing, and a sample introduction tube is provided at one end on the base. has a sample introduction hole connected to the housing, and the other end forms a sample introduction hole communicating with the constant temperature chamber, one end communicates with the constant temperature chamber, and the other end forms a sample guide hole communicating within the housing. A sample discharge hole is formed which has a sample discharge port that communicates with the interior of the spiral tube and has a sample discharge port connected to the other end of the spiral tube, and one end of the spiral tube is detachably connected to the other end of the sample introduction hole. The other end is removably connected to one end of the sample discharge hole, constant-temperature water is circulated in the constant temperature chamber, and the sample introduced from the sample introduction port is passed sequentially through the sample introduction hole, the spiral tube, and the sample guide hole. A flow cell device characterized in that the sample is introduced into a housing, brought into contact with an electrode inserted into the housing from the upper end side, and then discharged from the sample discharge port through the sample discharge hole.