Rapid separation method for 223Ra, 225Ac and 232Th in radioactive solution

Abstract

The invention discloses a method for rapidly separating < 223 > Ra, < 225 > Ac and < 232 > Th in a radioactive solution. The method comprises the following steps: (1) loading the radioactive solution into a chromatographic column filled with an inorganic microsphere material; the radioactive solution at least contains 223 Ra, 225 Ac and 232 Th; and (2) eluting the chromatographic column by adopting a first eluting agent to respectively obtain 223Ra and 225Ac. According to the method, a high-performance chromatographic separation mode is adopted, the separation degree is higher, the three elements of thorium, radium and actinide can be completely separated, the purity of separated products is high, the separation speed is high, and separation can be completed within about 60 minutes.

Description

Technical Field

[0001] This invention belongs to the field of radioactive medical α-isotope separation and purification technology, specifically, it relates to a method for separating and purifying radioactive α-isotopes in a radioactive solution. 223 Ra、 225 Ac and 232 A fast separation method for Th. Background Technology

[0002] Radiotherapy-based alpha-isotope targeted therapy (TAT) is a specific and targeted tumor treatment method with advantages such as strong radiobiological effects, high linear energy transfer density, and suitable range in soft tissues (cellular scale). TAT can efficiently kill tumor cells while minimizing damage to adjacent normal tissue cells. Therefore, radiotherapy-based alpha-isotope drugs show promising applications for small tumors, scattered carcinomas, and micrometastases, and are currently a research hotspot in therapeutic radiopharmaceuticals. However, due to the stringent requirements on isotope half-life, purity, drug labeling ability, in vivo distribution, and stability, the types of radiotherapy-based alpha-isotopes available are limited, with radium-223 being a less common choice. 223 Ra) and Actinium-225 225 Actinium (Ac) is among the most commercially promising radioactive medical alpha isotopes. However, the scarcity of radium-223 (approximately 40 curies globally) and actinium-225 (approximately 7 curies globally) limits the development of new alpha isotope drugs, leaving many patients without access to treatment. The extremely limited sources of radioactive medical alpha isotopes, coupled with the high difficulty in their preparation and purification, make their insufficient supply a major bottleneck currently hindering the development and future clinical application of radioactive medical alpha isotope drugs.

[0003] Currently, the internationally recognized technology for mass production of actinium-225 and radium-223 is to use high-energy ions to bombard a thorium target. 232 Th(p,X) 225 Ac or 232 Th(p,X) 223 Ra(β - ) 225 Acrylic acid (Ac) reactions are used to produce isotopes such as actinium-225 and radium-223. However, this process generates a large number of isotopes, resulting in a highly complex sample composition that is difficult to separate and purify. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a radioactive solution... 223 Ra、 225 Ac and 232 A rapid separation method for Th, which enables the rapid separation of three elements: radium, actinium, and thorium.

[0005] The technical solution of the present invention is as follows;

[0006] In a radioactive solution 223 Ra、 225 Ac and 232 A method for separating Th, the method comprising:

[0007] (1) Loading a radioactive solution into a chromatographic column packed with inorganic microspheres; the radioactive solution contains at least... 223 Ra、 225 Ac and 232 Th;

[0008] (2) The chromatographic column was eluted with the first eluent to obtain the following results: 223 Ra and 225 Ac.

[0009] According to an embodiment of the present invention, in step (2), the contents of the sample are collected. 223 Ra effluent and containing 225 After the Ac effluent flows out, the remaining solution containing the first rinsing agent contains 232 Th.

[0010] According to an embodiment of the present invention, the method further includes:

[0011] (3) The chromatographic column obtained after eluting with the first eluent contains 223 Ra effluent and containing 225 Ac effluent was added to the salt transfer column, and then eluted with a second eluent to obtain salts with increased activity concentration. 223 Ra first product and containing 225 Ac is the second product.

[0012] According to an embodiment of the present invention, in step (1), the radioactive solution, 223 The activity of Ra is 0.001-10 mCi.

[0013] According to an embodiment of the present invention, in step (1), the radioactive solution, 225 The activity of Ac is 0.001-10 mCi.

[0014] According to an embodiment of the present invention, in step (1), the radioactive solution, 232 The concentration of Th is 1-1000 mg / L.

[0015] According to an embodiment of the present invention, in step (1), the solvent used in the radioactive solution is selected from one or more of the following: nitric acid aqueous solution, hydrochloric acid aqueous solution, citric acid aqueous solution, α-hydroxyisobutyric acid aqueous solution, oxalic acid aqueous solution, and tartaric acid solution.

[0016] According to an embodiment of the present invention, taking an aqueous nitric acid solution as an example, the concentration of the aqueous nitric acid solution is 0.01-5%, preferably 0.01-1%.

[0017] According to an embodiment of the present invention, in step (1), the flow rate of the radioactive solution in the chromatographic column is 0.1-10 mL / min, preferably 1-5 mL / min.

[0018] According to an embodiment of the present invention, in step (1), the chromatographic column is made of stainless steel or polyetheretherketone.

[0019] According to an embodiment of the present invention, in step (1), the length of the chromatographic column is 5 to 25 cm and the inner diameter is 2 to 10 mm.

[0020] According to an embodiment of the present invention, in step (1), the particle size of the inorganic microsphere material is 2-200 μm, preferably 5-60 μm.

[0021] According to an embodiment of the present invention, in step (1), the pore size of the inorganic microsphere material is... Preferred

[0022] According to an embodiment of the present invention, in step (1), the inorganic microsphere material is selected from one or two of carboxyl-modified silicon dioxide and graphitized carbon.

[0023] According to an embodiment of the present invention, the graphitized carbon is prepared by the following method:

[0024] SiO2, resorcinol and formaldehyde aqueous solution are mixed for prepolymerization reaction, and then the prepolymerized solution is added to an organic solvent containing surfactant for polymerization reaction. Finally, the product of polymerization reaction is heated and calcined to obtain graphitized carbon.

[0025] Preferably, the concentration of the formaldehyde aqueous solution is 30-50 wt%.

[0026] Preferably, the molar ratio of resorcinol to formaldehyde is (1-1.5):1.

[0027] Preferably, the molar ratio of SiO2 to resorcinol is 1:(1-4).

[0028] Preferably, the temperature of the prepolymerization reaction is 80-100℃, and the time of the prepolymerization reaction is 1-3h.

[0029] Preferably, the polymerization temperature is 150-170℃ and the polymerization time is 40-50h.

[0030] Preferably, the surfactant is a cationic surfactant selected from one or more of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, and octadecyldimethylbenzyl quaternary ammonium.

[0031] Preferably, the organic solvent is a short-chain fatty alcohol, and more preferably one or more of n-hexanol, n-heptanol, and n-pentanol.

[0032] Preferably, the surfactant has a mass fraction of 0.1-0.3% in the organic solvent.

[0033] Preferably, the heating and calcination temperature is 1800-3000℃; the heating and calcination time is 4-8h.

[0034] According to an embodiment of the present invention, the carboxyl-modified silica is prepared by the following method:

[0035] A first reaction was carried out by mixing vinyltriethoxysilane, tetraethyl orthosilicate (TEOS), and a solvent; the resulting intermediate was then mixed with a surfactant, water, and succinic anhydride for a second reaction to obtain carboxyl-modified silica.

[0036] Preferably, the molar ratio of vinyltriethoxysilane to tetraethyl orthosilicate is (1-1.2):5.

[0037] Preferably, the molar ratio of the surfactant to succinic anhydride is (1-1.5):10. In this invention, the water content is not particularly limited, as long as it is sufficient to dissolve all the raw materials.

[0038] Preferably, the molar ratio of the vinyltriethoxysilane to the surfactant is (10-20):1.

[0039] Preferably, the surfactant is a cationic surfactant selected from one or more of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, and octadecyldimethylbenzyl quaternary ammonium.

[0040] Preferably, the temperature of the first reaction is 40-45℃, and the reaction time is 15-20h.

[0041] Preferably, the temperature of the second reaction is 50-60℃, and the reaction time is 8-10h.

[0042] For example, the method for preparing the carboxyl-modified silica is as follows:

[0043] Vinyltriethoxysilane, tetraethyl orthosilicate (TEOS), and ethanol were mixed and reacted at 40-45°C for 15-20 h. The reaction solution was then rotary evaporated to obtain silica sol. A surfactant, water, and succinic anhydride were then mixed and added to the silica sol, and the mixture was stirred at 50-60°C for 8-10 h. After the reaction was completed, the reaction solution was filtered and then washed with methanol and ultrapure water in sequence. The solution was then dried at 50-60°C for 1-12 h to obtain carboxyl-modified silica.

[0044] According to an embodiment of the present invention, in step (2), the first rinsing agent is an aqueous solution of an organic carboxylate buffer salt. Exemplarily, the first rinsing agent may be selected from one or more of the following: citric acid aqueous solution, α-hydroxyisobutyric acid aqueous solution, oxalic acid aqueous solution, and tartaric acid aqueous solution.

[0045] According to an embodiment of the present invention, in step (2), the concentration of the first rinsing agent is 20-2000 mmol / L, preferably 100-1000 mmol / L; for example, the concentration of the organic carboxylate buffer solution is 20-2000 mmol / L, preferably 100-1000 mmol / L.

[0046] According to an embodiment of the present invention, in step (2), the pH value of the first rinsing agent is in the range of 1-6, preferably 2-5.

[0047] According to an embodiment of the present invention, the pH of the first rinsing agent is adjusted by a pH adjuster, wherein the pH adjuster is selected from one or more of ammonia, ethylenediamine, and sodium hydroxide.

[0048] According to an embodiment of the present invention, in step (2), the flow rate of the first rinsing agent is 0.1-10 mL / min, preferably 1-5 mL / min.

[0049] According to an embodiment of the present invention, in step (3), the salt transfer column is selected from one or more of the following: silica, polymethyl methacrylate bonded carboxyl, polystyrene bonded sulfonic acid, etc.

[0050] According to an embodiment of the present invention, in step (3), the second rinsing agent is a strong acid aqueous solution. Exemplarily, the second rinsing agent may be selected from one or more of hydrochloric acid, nitric acid, and sulfuric acid.

[0051] Preferably, the concentration range of the second rinsing agent is 0.01-0.5 mol / L, more preferably 0.05-0.3 mol / L. Preferably, the concentration range of the strong acid aqueous solution is 0.01-0.5 mol / L, more preferably 0.05-0.3 mol / L.

[0052] According to an embodiment of the present invention, in step (3), the flow rate of the second rinsing agent is 0.1-10 mL / min, preferably 1-5 mL / min.

[0053] According to an embodiment of the present invention, in step (3), the containing 223 The first product of Ra is a highly radioactive nucleus with high purity and high activity concentration. 223 Ra solution.

[0054] According to an embodiment of the present invention, in step (3), the containing 225 Ac's second product is a highly radioactive nucleus with high radioactivity concentration. 225 Ac solution.

[0055] Preferably, the radioactive nucleus has a purity of ≥95%, for example 95%, 96%, 97%, 98%, 99%, or 100%.

[0056] Preferably, the radioactivity concentration is ≥3.75 MBq / mL.

[0057] According to an embodiment of the present invention, in step (2), the chromatographic column is eluted with a first eluent, and the eluent is collected over time. The eluents from different time periods contain [specific components / elements]. 223 Ra effluent containing 225 Ac effluent, and containing 232 The effluent from Th. That is, the first fluid collected containing Th. 223 The effluent from Ra was collected, and then the contents were gathered. 225 The effluent from Ac was finally collected and contained... 232 The effluent from Th.

[0058] Preferably, the effluent can be collected at intervals of 0.5-3 minutes. For example, one tube of effluent can be collected every 0.5-3 minutes.

[0059] 223 Ra、 225 Ac and 232 Each of the Th samples has its own characteristic gamma-ray spectral peaks; the composition of each sample tube is determined by measuring the energy spectrum of the samples using a gamma-ray spectrometer; by adjusting the collection time of the eluent, each sample tube contains only a single component nuclide; so that... 223 Ra、 225 Ac and 232 Th separation.

[0060] According to an embodiment of the present invention, in step (3), the data obtained in step (2) for different time periods are... 223 Ra effluent and containing 225 Ac effluent was added separately to the salt transfer column, and then eluted separately with a second eluent to obtain salts containing...223 Ra first product and containing 225 Ac is the second product.

[0061] Beneficial effects of the present invention

[0062] Compared with existing technologies, the method of this invention adopts a high-efficiency chromatographic separation mode, which has a higher degree of separation and can achieve complete separation of the three elements thorium, radium and actinium. The separation product has high purity and fast separation speed, and the separation can be completed in about 60 minutes. Attached Figure Description

[0063] Figure 1 This is a scanning electron microscope image of the graphitized carbon microsphere material prepared in Example 1.

[0064] Figure 2 This is a scanning electron microscope image of the carboxyl-modified silica microsphere material prepared in Example 2.

[0065] Figure 3 This is the infrared spectrum of the carboxyl-modified silica microsphere material prepared in Example 2.

[0066] Figure 4 The separation spectra of Ra-223 (10 μCi), Ac-225 (10 μCi), and Th (95 mg / L) in Example 1 are shown.

[0067] Figure 5 The separation spectra of Ra-223 (10 μCi), Ac-225 (10 μCi), and Th (950 mg / L) in Example 2 are shown.

[0068] Figure 6 This is the gamma spectrum of the first product Ra-223 and its daughter isotopes in Example 2.

[0069] Figure 7 This is the gamma spectrum of the second product Ac-225 and its daughter isotopes in Example 2.

[0070] Figure 8 The separation spectra of Ra-223 (10 μCi), Ac-225 (10 μCi), and Th (950 mg / L) in Example 3 are shown.

[0071] Figure 9 This is the gamma spectrum of the first product Ra-223 and its daughter isotopes in Example 3.

[0072] Figure 10 This is the gamma spectrum of the second product Ac-225 and its daughter isotopes in Example 3. Detailed Implementation

[0073] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0074] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0075] The main instruments involved in the following embodiments are as follows:

[0076] Ultraviolet detector (Beijing Xiangyue Huanyu Technology Development Co., Ltd., UC-3292), Gamma spectrometer (ORTECTETRAD, TETRAD-20)

[0077] Preparation Example 1

[0078] Preparation of graphitized carbon microsphere fillers

[0079] 3.0042 g SiO2 was dispersed in a mixture of 11.011 g resorcinol and 9.1 mL formaldehyde aqueous solution (30 wt%), and prepolymerized in an oil bath at 80 °C for 1 h. The prepolymerized solution was then added to a 9.1 mL n-hexanol solution containing 0.073 g cetyltrimethylammonium bromide, and reacted in an oil bath at 160 °C for 48 h. Finally, calcination at 1800 °C for 4 h yielded graphitized carbon microspheres. Figure 1 ), Figure 1 This is a scanning electron microscope image of the graphitized carbon microsphere material prepared in Example 1.

[0080] Preparation Example 2

[0081] Preparation of carboxyl-modified silica fillers

[0082] (1) To prepare silica sol, weigh 1 mL of vinyltriethoxysilane, 5 mL of tetraethyl orthosilicate (TEOS) and 20 mL of ethanol and mix them. React at 45 °C for 16 h. Then, rotary evaporate the above reaction solution to obtain silica sol.

[0083] (2) 0.0364 g of hexadecyltrimethylammonium bromide, 20 mL of deionized water, and 1.5011 g of succinic anhydride were added to a flask and mixed with stirring. Then, silica sol was added to the reaction vessel, and the mixture was stirred at 55 °C for 8 h. After the reaction was completed, the reaction solution was filtered, washed with methanol and ultrapure water, and dried at 50 °C for 1 h to obtain carboxyl-modified silica microspheres. Figure 2-3 ), Figure 2 This is a scanning electron microscope image of the carboxyl-modified silica microsphere material prepared in Example 2. Figure 3 This is the infrared spectrum of the carboxyl-modified silica microsphere material prepared in Example 2.

[0084] Example 1

[0085] Separation of low-concentration Th-232 from Ra-223 and Ac-225

[0086] A 95 mg / L thorium nitrate solution (i.e., a radioactive solution) containing 10 μCi Ra-223 and 10 μCi Ac-225 was used. A 4.6*250 mm column packed with graphitized carbon (as described in Preparation Example 1) was employed. The radioactive solution was loaded into the column, which was also packed with inorganic microspheres. The flow rate of the radioactive solution in the column was 1 mL / min. A 1 M α-hydroxyisobutyric acid aqueous solution (adjusted to pH 4.5 with ammonia) was used as the mobile phase at a flow rate of 1 mL / min, with an injection volume of 100 μL. The sample was then eluted with a 1 M citric acid aqueous solution (pH 4). One sample was collected every 1 minute and detected using a gamma spectroscopy spectrometer and a post-column derivatization UV detector. Separation spectra of 10 μCi Ra-223, 10 μCi Ac-225, and 95 mg / L Th were obtained. Figure 4 The entire separation process took 70 minutes. Figure 1 As can be seen, Th-232 is completely separated from Ra-223 and Ac-225.

[0087] Example 2

[0088] Separation of high concentrations of Th-232 from Ra-223 and Ac-225

[0089] A 950 mg / L thorium nitrate solution containing 10 μCi Ra-223 and 10 μCi Ac-225 was used. A 4.6 x 250 mm column packed with graphitized carbon (as in Preparation Example 1) was employed. The radioactive solution was loaded into the column packed with inorganic microspheres at a flow rate of 1 mL / min. 1 M α-hydroxyisobutyric acid (adjusted to pH 4.5 with ammonia) was used as the mobile phase at a flow rate of 1 mL / min, with an injection volume of 100 μL. The sample was then eluted with 1 M citric acid aqueous solution (pH = 4). One sample was collected every 1 minute, resulting in a total of 60 samples. These samples were detected using gamma spectroscopy and a post-column derivatization UV detector (samples 2-7 contained Ra-223, samples 10-22 contained Ac-225, and samples 23-60 contained Th). The resulting spectra are shown below. Figure 5 As shown, Figure 5 As can be seen, Th-232 can be completely separated from Ra-223 and Ac-225.

[0090] Then, samples from tubes 2-7 were combined and added to a silica transfer column, and eluted with 0.1M HCl aqueous solution (the second eluent) at a flow rate of 1 mL / min. The collected product was the first product. Samples from tubes 10-25 were combined and added to the silica transfer column, and eluted with 0.1M HCl aqueous solution at a flow rate of 1 mL / min. The collected product was the second product. Finally, the radioactive purity of the first and second products was determined using a gamma-ray spectrometer. Figure 6-7 The entire separation process took 60 minutes.

[0091] Figure 6 The first product 223 Ra gamma spectrum Figure 6 Can be found 223 Ra's main peak (269.41 keV), and without 225 Ac and its daughter isotopes 221 Fr and 213 The presence of the Bi peak indicates that the product has extremely high radioactive purity.

[0092] Figure 7 For the second product 225 Ac's gamma spectrum, due to 225 Ac decays almost entirely with alpha, producing extremely low gamma-ray abundance around 100 keV, resulting in a low signal-to-noise ratio, which is clearly visible in the spectrum. 225 daughter nuclides of Ac 221 Fr(218KeV) and 213 The peak of Bi (440.45 keV) was not observed. 223 The peaks of Ra and its daughter nuclides indicate that the second product also has extremely high radionuclear purity.

[0093] Example 3

[0094] The rest is the same as in Example 2, except that the carboxyl-modified silicon dioxide of Preparation Example 2 is used instead of graphitized carbon.

[0095] The first and second products after separation were detected by gamma spectroscopy and post-column derivatization UV detector, respectively. The resulting spectra are shown below. Figure 8 As shown, Figure 8 As can be seen, the entire separation process took 60 minutes, and the peak times of Th-232, Ra-223, and Ac-225 were staggered, indicating that Th-232, Ra-223, and Ac-225 had been completely separated.

[0096] Finally, the radioactive purity of the first and second products was determined using a gamma-ray spectrometer. Figure 9-10 ), Figure 9 First product 223 Ra gamma spectrum Figure 6 You can see 223 The main peak of Ra (269.41 keV) has no... 225 Ac and its daughter isotopes 221 Fr and 213 Bi's peak.

[0097] Figure 10 For the second product 225 The gamma spectrum of Ac Figure 7 It is obvious 225 daughter nuclides of Ac 221 Fr(218KeV) and 213 The peak of Bi (440.45 keV) was not observed. 223 The peaks of Ra and its daughter nuclides indicate that the product has extremely high radionuclear purity.

[0098] The embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for the separation of Ra from a radioactive solution comprising the steps of: 223 Ra, 225 Ac and 232 Th, characterized in that, The method comprises: (1) loading a radioactive solution into a chromatographic column packed with inorganic microspherical material; said radioactive solution containing at least 223 Ra, 225 Ac and 232 Th; (2) eluting the chromatographic column with a first eluent to obtain 223 Raand 225 Ac.

2. The method of claim 1, wherein, In step (2), the Ra effluent and the Th effluent are collected 223 Ra effluent and the Th effluent are collected 225 After the Ac effluent, the remaining solution containing the first eluent contains 232 Th.

3. The method according to claim 1 or 2, characterized in that, The method further comprises: (3) the Ra effluent obtained after eluting the first eluent from the column 223 Ra effluent and the Ac effluent are added to a salt exchange column, respectively, and are eluted with a second eluent, respectively, to obtain a Ra first product and an Ac second product, respectively, with increased activity concentration 225 Ra effluent and the Ac effluent are added to a salt exchange column, respectively, and are eluted with a second eluent, respectively, to obtain a Ra first product and an Ac second product, respectively, with increased activity concentration 223 Ra effluent and the Ac effluent are added to a salt exchange column, respectively, and are eluted with a second eluent, respectively, to obtain a Ra first product and an Ac second product, respectively, with increased activity concentration 225 Ra effluent and 4. The method according to any one of claims 1 to 3, characterized in that, In step (1), the radioactivity of the solution is between 0.001 and 10 mCi. 223 The activity of Ra is between 0.001 and 10 mCi. Preferably, 225 The activity of Ac is 0.001-10 mCi. Preferably, in step (1), the radioactive solution, 232 The concentration of Th is 1-1000 mg / L. Preferably, in step (1), the solvent used in the radioactive solution is selected from one or more of nitric acid aqueous solution, hydrochloric acid aqueous solution, citric acid aqueous solution, alpha-hydroxyisobutyric acid aqueous solution, oxalic acid aqueous solution, and tartaric acid solution.

5. The method according to any one of claims 1 to 4, characterized in that, In step (1), the inorganic microspherical material is selected from one or both of carboxyl-modified silica and graphitized carbon. Preferably, the graphitized carbon is prepared by the following method: SiO2, resorcinol and formaldehyde aqueous solution are mixed for pre-polymerization, then the pre-polymerized solution is added to an organic solvent containing a surfactant for polymerization, and finally the polymerization product is calcined by heating to obtain graphitized carbon. Preferably, the carboxyl-modified silica is prepared by the following method: Vinyltriethoxysilane, tetraethyl orthosilicate and a solvent are mixed for a first reaction; the obtained intermediate product is mixed with a surfactant, water and succinic anhydride for a second reaction to obtain carboxyl-modified silica.

6. The method according to any one of claims 1 to 5, characterized in that, In step (2), the first eluent is an organic carboxylic acid salt buffer saline solution. Illustratively, the first eluent is selected from one or more of citric acid aqueous solution, alpha-hydroxyisobutyric acid aqueous solution, oxalic acid aqueous solution, and tartaric acid aqueous solution. Preferably, in step (2), the concentration of the first eluent is 20-2000 mmol / L. Preferably, in step (2), the pH value of the first eluent ranges from 1 to 6.

7. The method according to any one of claims 1 to 6, characterized in that, The transsalt column is selected from one or more of silica, polymethacrylate-bonded carboxyl, and polystyrene-bonded sulfonic acid.

8. The method according to any one of claims 1 to 7, characterized in that, In step (3), the second eluent is a strong acid aqueous solution. Illustratively, the second eluent is selected from one or more of hydrochloric acid, nitric acid, and sulfuric acid. Preferably, the concentration of the second eluent ranges from 0.01 to 0.5 mol / L.

9. The method according to any one of claims 1 to 8, characterized in that, In step (3), the Ra-containing solution 223 The first product, Ra, is a high radionuclide purity, high radionuclide activity concentration 223 Ra solution. Preferably, in step (3), the solution containing 225 The Ac second product is a high radionuclide purity, high radionuclide activity concentration 225 Ac solution. Preferably, the radioactivity purity is ≥95%, for example, 95%, 96%, 97%, 98%, 99%, or 100%. Preferably, the radioactivity concentration is ≥3.75 MBq / mL.

10. The method according to any one of claims 1 to 9, characterized in that, In step (2), the column is eluted with the first eluent, and the effluent is collected by time. The effluent collected at different time periods contains 223 Ra, the effluent contains 225 Ac, and the effluent contains 232 Th, respectively. Preferably, in step (3), the different time period containing 223 Ra effluent and the containing 225 Ac effluent are separately added into a salt exchange column, and are separately eluted with a second eluent to obtain a first product containing 223 Ra and a second product containing 225 Ac, respectively.

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