JPS58204343A - Measuring apparatus of hydrogen ion concentration - Google Patents

Abstract

PURPOSE:To perform safely the measurement of a radioactive substance in high accuracy and to facilitate the remote maintenance of calibration work etc., by utilizing a light guide. CONSTITUTION:Light emitted from a light source 15 passes through a spectorscope 14 and is made into a signal monochrome, and is made incident to an absorbance measuring cell 11 through a light guide 13a of the light incidence side. Then, the quantity of the light is felt by absorption and said light arrives at a photodetector 14 through a light guide 13b of the light emitting side. At this time, a liquid in the cell 11 is a diluted sample liquid 5 and is flowed at a fixed running speed by a constant flow pump 8 and an increase of absorbing quantity of light, that is, the concentration of a hydrogen ion is found by measuring a decrease of transmitting quantity of pulse-like light at the operating time by using the transmitting quantity of the light at the non-operating time of an adding device 10 of pH indicator as a base line. In this manner, in case of treating a radioactive substance as a sample, maintenance work, etc. are carried out safely and easily by installing the part of the cell 11 inside a shielding body 17 such as a lead cell, a globe box etc. and installing the light source 15 etc. outside the cell 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to a hydrogen ion concentration measuring device, and mainly relates to a measuring device for measuring the hydrogen ion concentration of a solution containing a radioactive substance.

[Technical background of the invention and its problems]

Generally, when measuring the hydrogen ion concentration of a solution containing a radioactive substance, a titration method or a pH measurement method using glass polarization has been used. However, in the titration method, if the sample contains a large amount of metal, precipitates may form as the titration progresses. A method has been used in which a fixed amount of a measurement sample is taken and titration is performed. Conventional measuring devices using these methods have problems in that it is more difficult to detect the titration end point than in normal neutralization titration, the operation is complicated, and the amount of sample required is large.

In addition, although the measurable concentration range a is large with a pH measuring device using a glass electrode, it is difficult to accurately measure a narrow concentration range, and it also requires supplementary light of the magnetic pole liquid and calibration operations. [Objective of the Invention] The purpose of the invention is to eliminate the drawbacks of the conventional hydrogen ion concentration measuring device described above, and to provide a highly accurate hydrogen ion concentration that can be measured with a small number of samples and that can be easily maintained remotely. Provide measuring equipment. There is a particular thing.

[Summary of the invention]

The non-inventive feature is a sample measurement cell into which a sample to be measured has been diluted and a pH indicator is added, a light incident side light guide provided so that the light source enters the zero sample measurement cell, and this light incident side. The present invention is a hydrogen ion concentration measuring device including a light emitting light guide provided so that light from the light guide passes through the measurement sample and guides the light to an optical analysis device such as a photodetector.

〔Effect of the invention〕

According to the present invention, even measurement samples of radioactive substances can be measured safely and with high precision, and remote maintenance such as calibration work can be easily performed.

[Embodiments of the invention]

Embodiments of the hydrogen ion concentration measuring device according to the present invention will be described below with reference to the drawings.

In FIG. 1, a sample suction end 1a of a diluter 1 is fixed to a vertically rotating arm 2a of a support base 2 having a vertically rotating mechanism.
The support stand 2 is driven by an external power source (not shown), such as compressed air.

The vertically rotating arm 2a is normally located above the dilution tank 3, rotates to a position above the sample container 4 by the driving force of compressed air, and then descends. In this state, the sample suction end 1a enters the sample liquid 5 in the sample container 4, and by causing the diluter 1 to perform a sample suction operation, a certain amount of the sample liquid 5 is aspirated. After completing the sample suction operation, the vertically rotating arm 2a is driven in the opposite direction to return the sample suction end 1a to the position above the dilution tank 3, and the diluter 1 is operated to draw the sample and diluent from the sample suction end 1a. Also, the diluter 1 fixed above the dilution tank 3
The diluent is discharged from the diluent discharge end 1b. The dilution tank 3 is placed on a stirring table 6, and a stirrer 6a is placed inside the dilution tank 3. After discharging the sample and diluent, stirring is performed to mix the diluted sample solution 7 in the dilution tank 3. equalize. The diluted sample liquid 7 is sucked by the fixing cap 8 through the diluted sample liquid suction end 9a, which is fixed at a height below the liquid level of the diluted sample liquid 7 in the dilution tank 3, and is transferred to the diluted sample liquid transport W9. The pH indicator addition device 10
Increased by +11. The pH indicator addition device can be of any type that can inject a large amount of the indicator, but for example, a channel switching type device as shown in FIG. 2 can be used. After adding the indicator, the liquid fills the coiled capillary column 9b, is stirred, enters the absorbance measurement cell 11, passes through the drain pipe 12, and is connected to a drain tank (not shown).

The light absorbing panel J11 has a light guide 13 in contact with the light transmitting window surfaces 11a and 11b, and the light guide 1 on the light incident side
A spectrometer 14 and a light source 15 are provided at the other end of the light guide 3a, and a photodetector 16 is provided at the other end of the light guide 13b on the light output side. The light source 15 is pi (one that can obtain light at the absorption wavelength of the indicator, for example, when the indicator is thymol blue, a halogen lamp can be used. The spectrometer @14 is one that monochromatizes light at the absorption wavelength, for example, diffraction). A grating spectrometer, an interference filter, etc. can be used.A photomultiplier tube, a photocell, etc. can be used as the photodetector 16.St can also be installed just before the spectrometer 16, and a light guide 13 on the light incidence side can be used.
It is also possible to directly inject white light into the photodetector 16 and use a multi-channel photodetector 16 to simultaneously measure the light dispersed by the spectrometer 14 using a polychromator.

The light emitted from the light source 15 passes through the spectroscope 14i, becomes monochromatic, passes through the light guide 132k on the light input side, enters the absorbance measurement cell 11, is completely absorbed, reduces the light intensity, and passes through the light guide 13b on the light output side. The liquid in the absorbance measurement cell 11 that reaches the photodetector 16 is caused to flow at a constant flow rate by the metering pump 8, and the amount of light transmitted when the pkI indicator mulberry addition device 10 is not operated is used as a baseline, and the liquid is operated. By measuring the decrease in the amount of light transmitted in a pulsed manner when the amount of light is absorbed, the increase in the amount of light absorption, that is, the hydrogen ion concentration can be determined.

Fig. 2 shows a flow path switching type Pi (indicator addition device 1o).The indicator 1ob enters the indicator tank 10a and is passed through the indicator transport pipe 10d by the pump 10c; the shield is broken. When adding a fixed amount of indicator into the diluted sample liquid transport tube, rotate the flow path switching valve 10e by 180° around the central axis, and rotate the flow rate switching valve 10f by 120° counterclockwise.
'Turn at the same time and drain 10 g of indicator fluid through the flow path. Drainage liquid yLog is connected to a drainage tank (not shown).This allows the indicator in the constant volume separation tube 10h to flow to the diluted sample transport tube 9 side, and drains the sample liquid in the constant volume separation tube io<. After the flow T0 sample liquid is discharged to the drain pipe Log through the flow path switching pulp 10f, the flow path switching pulp is rotated clockwise for 120 minutes.
° Rotate to restore the flow path of the indicator.

In this device, by making the light guide 13 long, the absorbance measurement cell 11, the light source 15, the spectrometer 14, and the photodetector 16 can be installed apart from each other. 11 part as shield 1
For example, it is possible to install the light source 15 etc. inside a lead cell, glove box, etc. and install it outside the shield 17 for easy maintenance. When containing metals that tend to cause precipitation, pi (
Depending on the selection of the indicator, it is possible to perform measurements within a pH range that does not cause precipitation, and compared to PI measurements using glass electrodes, maintenance work such as periodic equipment calibration and polar solution replenishment is not required. Become.

Is the sample a strong acid in a free state? If the sample contains a metal salt solution, it is inappropriate to use it as a method for quantifying the amount of free strong acid.Furthermore, if the sample is radioactive, dilution can reduce the radioactivity and change the spectral transmittance characteristics of the light guide. Is it possible to make it smaller?

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of a hydrogen ion concentration measuring device according to the invention, and FIG. 2 is a diagram showing the configuration of Vemio for quantitatively adding a pH indicator. 1... Diluter, 5... Sample liquid, 10...
- pH indicator quantitative addition device, 11... Absorbance measurement cell, 13... Light guide, 13a... Light guide on the light incidence side, 13b...
Light guide on the light emission side, 14... spectrometer,
15... Light source, 16... Photodetector.

Claims (1)

[Claims] +1) A sample measurement cell section into which a measurement sample has been diluted and a pH indicator is added, and a spectrometer is installed in the sample measurement cell section. The light guide includes a light-incidence side light guide that receives spectroscopic monochromatic light, and a light-output side light guide that is provided in the sample measurement cell and that outputs light in the sample measurement cell so as to guide the light in the sample measurement cell to the photodetector. . A hydrogen ion concentration measuring device, characterized in that it is configured to measure the hydrogen ion concentration of a measurement sample from a change in absorbance due to the addition of the pH indicator. (2) The hydrogen ion concentration measuring device according to claim 1, characterized in that the sample-1 cell portion is installed in a shielded cell. :3) A patent characterized in that the radioactivity in a strong acid solution containing a large amount of radioactive metal salt is reduced by a diluter, and a pH indicator is added to the sample measurement cell section. A hydrogen ion concentration measuring device according to claim 1. (4) Inject white light into the light input light guide, install a spectroscope just in front of the photodetector, make this photodetector a multi-channel type, and convert the light dispersed by the spectrometer into a polymeter type. The hydrogen ion concentration measurement n ft according to claim 1, characterized in that the simultaneous photometry unit 5 is also configured.