JPH0457990B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting radioactive substances in a liquid sample using liquid chromatography. More specifically, the present invention relates to a method for detecting radioactive substances using a stimulable phosphor.

One method of separation analysis is to inject a sample solution into a packed tower (column) packed with an adsorbent, then inject an appropriate solvent to develop the sample, and then collect the sample components as they flow out of the column. Liquid chromatography is known. This liquid chromatography is also used to separate samples containing radioactive substances (substances containing radioactive isotopes), and is used to measure the radiation emitted from the eluate separated by liquid chromatography. The separation and identification of radioactive substances in samples is carried out using this method.

Traditionally, a method for measuring the radiation emitted from a liquid sample containing radioactive substances is to add a liquid scintillator, which is made by dissolving a solute (fluorescent agent) in an organic solvent, to the sample. Liquid scintillation methods, which involve detecting radiation as fluorescence, are widely used. In this method, a part of the radiation energy emitted from a radioactive substance in a sample is absorbed by a scintillator, and the radioactivity of the radioactive substance is measured by detecting the fluorescence (instantaneous luminescence) emitted from the scintillator. It is.

The liquid scintillation method described above is also applied to liquid chromatography of samples containing radioactive substances, and by separating a certain amount of the liquid sample flowing out of the column and adding a liquid scintillator, radiation from the sample is removed. measurements are being carried out.

That is, after a sample containing radioactive substances separated and developed by liquid chromatography is fractionated using a fraction collector, a liquid scintillator is added to each fraction, and the fluorescence emitted from the liquid scintillator is collected using a photomultiplier tube. By detecting and counting as electrical pulses, the radiation dose of each fraction is measured, and the radioactive substances in the sample are separated and identified.

In this way, the liquid scintillation method has the advantage of being able to detect radioactivity even when the radiation emitted from radioactive substances is weak radiation such as α-rays and β-rays. It has become a useful means for measuring radioactivity.

In the liquid scintillation method, the scintillator's light emission is caused by the energy of the radiation emitted from the radioactive substance in the liquid sample, which first excites the solvent molecules formed by dissolving the solute (fluorescent agent), and then excites them. It occurs when solute molecules are excited due to collisions between solvent molecules and solute molecules (scintillator). In addition to this process in which radiation energy is transferred from solvent molecules to solute molecules, energy is transferred between solvent molecules due to interactions between solvent molecules in an excited state and solvent molecules in a ground state. This also includes the case where the scintillator is excited after energy is transferred to another solute molecule due to the interaction between the excited solvent molecule and the solute molecule of an object other than the scintillator. In addition, this energy transfer occurs not only through interactions between molecules such as collisions, but also when the sitillator absorbs fluorescence emitted from excited solvent molecules or other solute molecules.

However, during this energy transfer process, the excitation energy is absorbed by some solvent molecules or other solute molecules and converted into heat, or the fluorescence generated by the scintillator is absorbed into the sample. A quenching phenomenon such as absorption by a light-absorbing substance also occurs at the same time.

The liquid scintillator essential in the liquid scintillation method is expensive and requires separation and purification before reuse. Furthermore, since it is difficult to recover scintillators with high purity, they are not often reused, and this also makes it difficult to reduce measurement costs. Furthermore, there are some problems in the handling of used scintillators containing radioisotopes, such as the difficulty in disposing of them.

Further, since the fluorescent agent used in the liquid scintillation method is an organic substance, the solvents that can be used are limited to organic solvents in most cases. Therefore, radioactive samples do not necessarily dissolve in solvents, and if the sample is poorly soluble in the solvent, it is necessary to select an appropriate solvent or devise a sample preparation method such as emulsifying and suspending the sample. do.

As mentioned above, liquid scintillators have a complex light emitting mechanism, so the counting efficiency tends to decrease (that is, the detected radioactivity intensity decreases) due to the quenching effect of mixed impurities and the sample itself. be. For example, fluorescence emitted from a scintillator is easily quenched by oxygen dissolved in the scintillator, or if the sample solution is colored, the colored substance also absorbs (ie, quenches) the fluorescence. Also,
When the sample is poorly soluble, it is difficult to make the sample solution into a homogeneous phase, while when the sample solution is in a heterogeneous phase, there are problems such as internal absorption of radiation emitted from the sample. Therefore, it is necessary to correct for the quenching caused by the various causes mentioned above to accurately determine the sample counting efficiency, which makes the measurement operation complicated.

Furthermore, in order to prevent a decrease in counting efficiency due to the quenching effect of impurities, contaminants, and colored substances mixed in the sample, careful preparation of the sample is required, and the measurer must have a high degree of skill and experience. is required.
In addition, pretreatment of the sample is required to remove the above-mentioned contaminants.

Furthermore, in the liquid scintillation method, radiation measurements of a sample are performed in real time.
That is, after adding a scintillator to a liquid sample, it is necessary to continuously measure light emitted from the scintillator for a certain period of time (for example, several minutes to several tens of minutes). In this measurement, when the intensity of radiation is low, the measurement time (measurement time) is long, and it cannot be said that the efficiency of measurement and the operating rate of the measuring device are sufficiently high.

Therefore, when the sample consists of a large number of samples as described above, there is a problem that it is difficult to process a large number of samples because the waiting time becomes long.
Another problem is that it takes time to obtain results. In particular, it is difficult to measure radiation when the radioactive isotope in the sample has a short half-life, and even more difficult when the intensity of the radiation is weak. This also means that the equipment used must be stable for long periods of time (e.g. against dark current drift in photomultiplier tubes), and in order to prevent this This results in either requiring expensive equipment or requiring experience and skill in adjusting the equipment.

The present inventor has conducted extensive research with the aim of solving the above-mentioned problems associated with the conventional liquid scintillation method used in liquid chromatography of samples containing radioactive materials. By sequentially supplying a plurality of radiation measurement containers containing an exhaustible phosphor to a sample supply device, a liquid sample is continuously or intermittently introduced into these measurement containers, and then the liquid sample is absorbed into the measurement containers. The inventors have discovered that the above-mentioned problems can be solved or the drawbacks reduced by utilizing a method of measuring radiation energy, and have arrived at the present invention.

That is, the present invention provides the following features: (1) A plurality of radiation measurement containers each containing a photostimulable phosphor are installed under a column filled with an adsorbent so as to receive and hold a liquid sample that has passed through the column. A step of introducing the liquid sample into each measurement container by sequentially supplying the liquid sample; (2) By leaving the plurality of measurement containers for a certain period of time, the radiation energy emitted from the radioactive substance in the liquid sample is (3) emitting the radiation energy stored in the plurality of measurement containers as photostimulated light and photoelectrically reading the photostimulated light; A method for detecting radioactive substances in a liquid sample using liquid chromatography, including the steps of: continuously measuring radioactivity in the liquid sample;

After absorbing radiation, the stimulable phosphor used in the present invention emits light (stimulated luminescence) when irradiated with electromagnetic waves (excitation light) such as visible light and infrared rays.
It has the property of showing. Therefore, by introducing a liquid sample containing a radioactive substance into a radiation measurement container containing a stimulable phosphor, the radiation emitted from the radioactive stool in the sample is absorbed into the measurement container, and then this measurement is performed. By irradiating a container with electromagnetic waves (excitation light) such as visible light and infrared rays, accumulated energy proportional to the radiation dose is released as fluorescence (stimulated luminescence). By photoelectrically reading this fluorescence and converting it into an electrical signal, the radiation emitted from the sample can be measured.

In the present invention, the emission time of the photostimulated light from the phosphor built into the radiation measurement container is instantaneous, and the photometric time of the stimulated light can be set regardless of the radiation intensity of the sample. The reading operation after introducing the sample into the measurement container and accumulating the radiation energy from the sample in the measurement container can be completed within several tens of seconds, thereby reducing the measurement time.

Furthermore, according to the present invention, by accumulating radiation energy from a sample in a radiation measurement container and then removing the sample, it is also possible to perform the accumulation operation and readout operation completely separately. Therefore, a plurality of measurement containers can be subjected to a readout operation at once. In this respect as well, the time required for conventional measurement can be shortened and the measurement operation can be simplified.

Therefore, the operating rate of the measuring device can be increased and the number of measurements can be increased. Furthermore, this means that
This means that even when using a radioactive isotope with a short half-life and low radiation intensity, measurements can be made with high accuracy under the same conditions. Furthermore, according to the present invention, even if only one measuring device is used, by preparing a plurality of measuring containers, it is possible to obtain the same measurement efficiency as using multiple measuring devices at the same time in the conventional method. It is something that can be done.

Furthermore, in the present invention, it is possible not only to automate the operation of moving and supplying a measurement container containing a stimulable phosphor and the operation of introducing a sample into the measurement container, but also to automate the measurement of radiation emitted from the sample. It is also possible to automate the operation of absorbing and accumulating radiation energy into the container and the operation of reading out the radiation energy accumulated in the measurement container, thereby further improving the workability.

Furthermore, the radiation measurement container used in the present invention does not require a conventional scintillator,
There is no need to mix (dissolve or suspend) the scintillator solution and sample in a container as in the liquid scintillation method, and the liquid sample containing the radioactive substance is simply placed in the measurement container containing the stimulable phosphor. Since measurement can be performed by introducing the sample, there is no need to separate and purify the sample after use.

Therefore, the radiation measurement container used in the present invention can be used repeatedly, and the cost per measurement can be reduced. Furthermore, since this measuring container is made of plastic material, it is very easy to handle.

Furthermore, if the radiation measurement container described above is used in radiation measurement, unlike the conventional liquid scintillation method, no solvent is required. Therefore, there is no need to particularly select a solvent or prepare a sample as in a liquid scintillator. In the present invention, the above-mentioned quenching phenomenon, especially the quenching phenomenon associated with fluorescence, does not occur. Therefore, there is no need to perform complicated extinction correction (determination of counting efficiency) for measuring the radioactivity of a sample, and the measurement operation is simplified in this respect as well.

Therefore, since there is no particular need to remove impurities contained in the sample, there is no need for conventional sample pretreatment, and a high degree of skill and care based on experience is required when preparing the sample. It's something you don't do. In this respect as well, radiation measurement of the sample can be easily performed.

Below, a radiation measurement container suitably used in the radioactive substance detection method of the present invention will be described.

The radiation measurement container used in the present invention usually consists of a sample storage part and a lid part. The lid part is not always necessary, and is used depending on the form of the measurement container, the type of sample, measurement conditions, etc.

The stimulable phosphor contained in the measurement container does not need to be contained throughout the measurement container, and may be contained only in a portion of the container. However, by increasing the surface area of the part containing the stimulable phosphor, the ability to capture radiation emitted from the sample is increased, improving the accuracy of measurement values and reducing the amount of radioactivity present in trace amounts in the sample. It becomes possible to detect substances or substances with weak radiation intensity. On the other hand, from the point of view of radiation energy readout operations, it is preferable that the stimulable phosphor is partially incorporated in the measurement container, and in this case, it is desirable that the stimulable phosphor be incorporated in the portion that comes into contact with the sample. In addition, from the viewpoint of the range of radiation emitted from the sample, the measurement container should be designed so that the distance between the built-in part of the stimulable phosphor and the radioactive substance (radiation source) in the sample is as small as possible. preferable.

Therefore, in the present invention, it is desirable that the shape of the measurement container be selected depending on the target sample amount, radiation intensity, and measurement conditions.

The stimulable phosphor used in the present invention is a phosphor that exhibits stimulated luminescence when irradiated with excitation light after absorbing radiation as described above. The phosphor is preferably a phosphor that exhibits stimulated luminescence in the wavelength range of 300 to 500 nm when excited by excitation light in the wavelength range of 800 nm. Examples of such stimulable phosphors include those described in U.S. Pat. No. 3,859,527.
Phosphors expressed by composition formulas such as SrS:Ce, Sm, SrS:Eu, Sm, ThO ₂ :Er, and La ₂ O ₂ S:Eu, Sm, as described in JP-A-55-12142.
ZnS: Cu, Pb, BaO・xAl ₂ O ₃ : Eu [However, 0.8
≦x≦10], and M ²⁺ O・xSiO ₂ :A [however,
M ²⁺ is Mg, Ca, Sr, Zn, Cd, or Ba, A is Ce, Tb, Eu, Tm, Pb, Tl, Bi, or Mn, and x is 0.5≦x≦2.5. A phosphor expressed by a composition formula such as (Ba _1-xy , Mg _x , Ca _y )FX: aEu ²⁺ [where
is at least one of Cl and Br,
A phosphor represented by the composition formula: x and y are 0<x+y≦0.6 and xy≠0, and a is 10 ^-6 ≦a≦5×10 ^-2 JP-A-12144-1987 stated in the issue
LnOX: xA [However, Ln is La, Y, Gd, and
At least one of Lu, X is at least one of Cl and Br, A is at least one of Ce and Tb, and x is 0<x<0.1
A phosphor expressed by the composition formula of (Ba _1-x , M〓 _x )FX:yA [where M〓 is Mg,
at least one of Ca, Sr, Zn, and Cd, X is at least one of Cl, Br, and I, A is Eu, Tb, Ce, Tm, Dy, Pr, Ho,
At least one of Nd, Yb, and Er, x is 0≦x≦0.6, and y is 0≦y≦0.2] JP-A-55-160078 stated in the official bulletin,
M〓FX・xA:yLn [However, M〓 is Ba, Ca, Sr,
At least one of Mg, Zn, and Cd, A
are BeO, MgO, CaO, SrO, BaO, ZnO,
Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO ₂ , TiO ₂ ,
ZrO ₂ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , and
At least one of ThO ₂ , Ln is Eu, Tb,
Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Sm,
and at least one of Gd, X is Cl,
At least one of Br, and I,
x and y are respectively 5×10 ^-5 ≦x≦0.5 and 0<y≦0.2] A phosphor is described in JP-A-56-116777 (Ba _{1- x} , M〓 _x )F ₂・aBaX ₂ :yEu, zA [However,
M〓 is beryllium, magnesium, calcium,
at least one of strontium, zinc, and cadmium; X is at least one of chlorine, bromine, and iodine; A is at least one of zirconium and scandium;
a, x, y, and z are each 0.5≦a≦1.25,
0≦x≦1, 10 ^-6 ≦y≦2×10 ^-1 , and 0<z
≦10 ^-2 ], described in Japanese Patent Application Laid-Open No. 57-23673, (Ba _1-x , M〓 _x )F ₂・aBaX ₂ :yEu, zB ,
M〓 is beryllium, magnesium, calcium,
at least one of strontium, zinc, and cadmium;
10 ^-6 ≦y≦2×10 ^-1 and 0<z≦10 ^-1 ] A phosphor is described in JP-A-57-23675 (Ba _1-x , M〓 _x )F ₂・aBaX ₂ :yEu, zA [However,
M〓 is beryllium, magnesium, calcium,
at least one of strontium, zinc, and cadmium; X is at least one of chlorine, bromine, and iodine; A is at least one of arsenic and silicon; a, x, y, and z are each 0.5 ≦a≦1.25, 0≦x≦1, 10 ^-6
≦y≦2×10 ^-1 and 0<z≦10 ^-1 ], M〓OX described in Japanese Patent Application No. 167498/1983 filed by the present applicant. :xCe[However, M〓 is Pr,
Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm,
is at least one trivalent metal selected from the group consisting of Yb, and Bi, X is one or both of Cl and Br, and x is 0<x<0.1]. The expressed phosphor is Ba _1-x M _x/2 L _x/2 FX:yEu ⁺² [However,
M represents at least one alkali metal selected from the group consisting of Li, Na, K, Rb, and Cs; L represents Sc, Y, La, Ce, Pr, Nd, Pm,
Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,
represents at least one trivalent metal selected from the group consisting of Al, Ga, In, and Tl; X is Cl,
represents at least one halogen selected from the group consisting of Br, and I; and x is 10 ^-2 ≦
x≦0.5, y is 0<y≦0.1] BaFX xA:yEu ⁺² [However, ,X is
is at least one halogen selected from the group consisting of Cl, Br, and I; A is a fired product of a tetrafluoroboric acid compound; and x is
10 ^-6 ≦x≦0.1, y is 0<y≦0.1] BaFX xA: yEu described in Japanese Patent Application No. 158048/1983 filed by the present applicant ⁺² [However, X is
at least one halogen selected from the group consisting of Cl, Br, and I; A is a hexafluoro compound consisting of a monovalent or divalent metal salt of hexafluorosilicic acid, exafluorotitanic acid, and hexafluorozirconic acid; and x is 10 ^-6 ≦x≦0.1, and y is 0<y≦0.1. BaFX・xNaX′: aEu ²⁺ described in Application No. 166320/1987 [However,
X and X' are each at least one of Cl, Br, and I, x and a are each 0<x≦2, and a is 0<a≦0.2]
A phosphor having the composition formula M〓FX・xNaX′:yEu ²⁺ :zA [where M〓 is Ba, Sr, and at least one alkaline earth metal selected from the group consisting of Ca; X and X' are Cl, Br, and I, respectively;
at least one halogen selected from the group consisting of; A is at least one transition metal selected from V, Cr, Mn, Fe, Co, and Ni; and x is 0<x≦2, y is 0<y≦
0.2, and z is 0<z≦10 ^-2 ], M〓FX・aM〓X′ described in the specification of Japanese Patent Application No. 184455/1983 filed by the present applicant.・bM′〓X″ ₂・cM〓
X ₃・xA:yEu ²⁺ [However, M〓 is at least one kind of alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; M〓 is Li, Na, K,
is at least one alkali metal selected from the group consisting of Rb, and Cs; M′〓 is Be and
is at least one divalent metal selected from the group consisting of Mg; M is at least one trivalent metal selected from the group consisting of Al, Ga, In, and Tl; A is a metal oxide; X is Cl, Br,
and at least one kind of halogen selected from the group consisting of I; X′, X″, and X are F,
at least one halogen selected from the group consisting of Cl, Br, and I; and a is 0≦
a≦2, b is 0≦b≦10 ^-2 , c is 0≦c≦10 ^-2 ,
and a+b+c≧10 ^-6 ; x is 0<x≦0.5,
y is 0<y≦0.2], and the like.

However, the stimulable phosphor used in the present invention is not limited to the above-mentioned phosphors, and any phosphor that exhibits stimulated luminescence when irradiated with excitation light after absorbing radiation can be used. It can be something.

Examples of materials for the radiation measurement container used in the present invention include glass; quartz; polyethylene;
Plastic materials such as polypropylene, nylon, Teflon, etc. may be mentioned.

A radiation measurement container can be obtained by incorporating a photostimulable phosphor into the above-mentioned material to form a container. Measurement container size, thickness, shape,
The amount and area of the built-in stimulable phosphor can be set depending on the amount of sample to be measured, measurement conditions, etc.

The above-mentioned stimulable phosphor may also be incorporated into the measurement container in a state of being dispersed in a binder.

Examples of binders include binders typified by proteins such as gelatin, synthetic polymeric substances such as polyvinyl acetate, nitrocellulose, polyurethane, polyvinyl alcohol, linear polyester, and the like.

Examples of the solvent for dispersing the stimulable phosphor particles in the binder include lower alcohols, chlorine atom-containing hydrocarbons, ketones, esters, and ethers.

The mixing ratio of the binder and the stimulable phosphor particles in the above dispersion varies depending on the shape of the intended measurement container, the type of phosphor particles, etc., but is usually 1:8.
The ratio is selected from the range of 1:40 to 1:40 (weight ratio).

Note that the dispersion liquid contains a dispersant for improving the dispersibility of the phosphor particles in the dispersion liquid, and
Various additives such as a plasticizer may be mixed to improve the bonding strength between the binder and the phosphor particles after molding.

The measurement container also has a layered structure consisting of a support made of a plastic material such as polyethylene terephthalate and a layer made of a binder in which the above-mentioned stimulable phosphor is dispersed (phosphor layer). You can leave it there. That is, the container may be formed by deforming a sheet consisting of a support and a phosphor layer by heat treatment or the like.

Alternatively, the measuring container of the present invention may have a form in which a molded article made of a binder in which a stimulable phosphor is dispersed is fitted into a part of the measuring container made of the above-mentioned material. In this case, the removable molded article is preferably coated with a transparent polymeric material such as polyethylene or polyethylene terephthalate in order to physically and chemically protect the stimulable phosphor.

In the present invention, it is not necessary to introduce the sample directly into the measurement container, but it is also possible to place another suitable container inside the radiation measurement container and introduce the liquid sample into the sample container for measurement. .

Next, the method for detecting radioactive substances of the present invention will be explained with reference to the schematic diagram shown in FIG. 1 of the accompanying drawings.

Figure 1 shows that in liquid chromatography,
FIG. 2 is a schematic illustration of a method for detecting radioactive substances contained in a liquid sample that is continuously dropped.

The sample to be measured in the present invention, ie, the liquid sample containing a radioactive substance, may be a solution or a suspension, or may be colored.

Furthermore, any type of radiation emitted from the radioactive substance in the sample can be measured, such as α rays, β rays, γ rays, proton rays, neutron rays, light rays, meson rays, and cosmic rays. That is, radiation from any radionuclide can be measured.

First, a liquid sample 4 is dropped from the bottom of a column 3 filled with an adsorbent in a sample introduction section 2 into a radiation measurement container 1 containing a photostimulable phosphor 1a, and a certain amount of the liquid sample is introduced. be done.

Next, in the radiation energy storage section 5,
At least a portion of the energy of the radiation emitted by the radioactive substance in the sample is absorbed by the stimulable phosphor in the measurement container 1 and accumulated. The accumulation time of this radiation energy (exposure time) varies depending on the intensity of radiation emitted from the radioactive substance contained in the sample, the amount and concentration of the substance, the shape of the measurement container, the intensity of stimulated luminescence, etc. , which usually takes about 1 second to 1 minute.

Next, in the stored energy readout section 6, the excitation light 8 emitted from the light source 7 enters the measurement container 1.
is irradiated. When the stimulable phosphor in the measurement container 1 is irradiated with excitation light, it emits stimulated luminescence with an amount of light proportional to the accumulated radiation energy, and this light enters a photodetector 9 such as a photomultiplier tube. do. The photodetector 9 has a filter attached thereto that transmits only light in the wavelength region of stimulated luminescence and cuts out light in the wavelength region of excitation light, so that only stimulated luminescence can be detected. is used. Photodetector 9
The detected stimulated luminescence is converted into an electrical signal, and after being amplified to an appropriate level electrical signal in an amplifier 10, it is input to a recording device 11.

In the recording device 11, the level of an electrical signal corresponding to the radiation dose absorbed by the measuring container 1, for example, the count value of electrical pulses, is displayed as a digital value. As the recording device 11, for example, one that scans the photosensitive measurement container with a laser beam or the like to record optically, one that displays electronically on a CRT, etc.
Recording devices based on various principles can be used, such as those that record radiation images displayed on a video printer or the like, and those that record on a heat-sensitive recording material using heat rays.

In addition, by providing a data processing circuit in the recording device 11, the radioactivity intensity can be calculated from the obtained digital value according to the readout efficiency (luminous efficiency of stimulated luminescence) and the accumulation time of radiation energy, which are input in advance. By calculating and further inputting the radioactivity intensity per molecule of the target radioactive substance, it is also possible to calculate the amount or concentration of radioactive substance per measurement container, and then display and record the obtained data. .

In addition, in the present invention, as a method for reading the radiation energy of the sample accumulated in the radiation measurement container, it is of course possible to use methods other than those exemplified above.

Furthermore, the operations according to the method for detecting radioactive substances of the present invention are not limited to the above-mentioned operations. It is also possible to efficiently separate radioactive substances. Furthermore, it is also possible to automate the entire measurement operation by continuously performing the operation of introducing a liquid sample into the radiation measurement container, the operation of accumulating radiation energy in the measurement container, and the operation of reading out the measurement container.

A used measurement container can be reused by cleaning it with an appropriate solvent or the like and then erasing the energy remaining in the measurement container by irradiating it with light or the like. Therefore, by reading out the measurement container without collecting the measurement container, and automating the operation of cleaning the used measurement container and erasing the remaining energy into the measurement process, it is possible to continuously reuse the container. becomes possible.

The method of detecting radioactive substances using liquid chromatography of the present invention can be suitably used when a large amount of liquid sample is used. Continuously and efficiently removes the radioactive substances contained in the
and can be detected quickly. Furthermore, it becomes possible to separate and identify radioactive substances in the separated and expanded liquid sample with high precision.

[Brief explanation of the drawing]

Figure 1 shows that in liquid chromatography,
1 shows a schematic explanatory diagram of a method for detecting radioactive substances contained in a liquid sample that is continuously dropped. 1: Radiation measurement container, 1a: Stimulable phosphor,
2: Sample introduction section, 3: Column filled with adsorbent, 4: Liquid sample, 5: Accumulation section, 6: Reading section,
7: light source, 8: excitation light, 9: photodetector, 10: amplifier, 11: recording device.

Claims (1)

[Scope of Claims] 1 (1) A radiation measurement container containing a stimulable phosphor is provided under a column filled with an adsorbent so as to receive and hold a liquid sample that has passed through the column. Step of introducing the liquid sample into each measurement container by sequentially supplying a plurality of liquid samples; (2) By leaving the plurality of measurement containers for a certain period of time, radiation energy emitted from the radioactive substance in the liquid sample is released. (3) emitting the radiation energy stored in the plurality of measurement containers as photostimulated light, and photoelectrically reading the photostimulated light; A method for detecting a radioactive substance in a liquid sample using liquid chromatography, comprising: continuously measuring radioactivity in the liquid sample. 2. The method for detecting a radioactive substance according to claim 1, wherein the radiation measurement container contains a binder containing and supporting the stimulable phosphor in a dispersed state. 3. The method for detecting a radioactive substance according to claim 1 or 2, wherein the radiation measurement container is a plastic container containing a photostimulable phosphor. 4. The method for detecting radioactive substances according to claim 1 or 2, wherein the radiation measurement container is a container made of glass or quartz containing a photostimulable phosphor. 5. The method for detecting a radioactive substance according to claim 1 or 2, wherein the stimulable phosphor is a divalent europium-activated alkaline earth metal fluorohalide phosphor.