Antimony isotope standard solution, preparation method and application

Abstract

The present application relates to the technical field of isotopic solution storage, and particularly relates to a standard solution of antimony isotopes, a preparation method and application, which comprises the following steps: dissolving antimony isotope particles in a mixed solution of reverse aqua regia and hydrofluoric acid, drying to obtain solid antimony isotope material; and dissolving the solid antimony isotope material in a nitric acid solution to obtain a standard solution of antimony isotopes, wherein reverse aqua regia and hydrofluoric acid are used as the dissolving system, and the hydrofluoric acid is used to complex Sb 3+ to form [SbF6] 3‑ , which effectively inhibits the hydrolysis of Sb 3+ and the drift of the isotopic ratio, the strong oxidizing property of reverse aqua regia ensures that Sb is completely converted into Sb 5+ , thereby avoiding the fluctuation of valence and realizing the long-term stable storage of the standard solution of antimony isotopes, and effectively solving the problems of the existing standard solution of antimony isotopes, such as easy hydrolysis and unstable valence.

Description

Technical Field

[0001] This invention relates to the field of isotope solution storage technology, specifically to an antimony isotope standard solution, its preparation method, and its application. Background Technology

[0002] Antimony (Sb), an important metallic element, exists in nature with various isotopes. Its isotopic composition undergoes regular changes during different geological processes, environmental variations, and biological metabolism, making antimony isotopes a powerful tracer tool. In geology, antimony isotopes can be used to study mineralization processes. By analyzing the ratios of antimony isotopes in antimony ore and related rocks, the origin of ore-forming materials can be traced, the evolution of ore-forming fluids and mineralization mechanisms can be understood, providing important evidence for geological exploration and mineral resource assessment. In environmental science, antimony isotopes play a crucial role in tracing the sources of environmental pollutants. Antimony-containing substances emitted from different pollution sources have different antimony isotopic characteristics. By measuring the ratios of antimony isotopes in the environment, the source of pollutants can be accurately identified, the degree of impact of different pollution sources on the environment can be assessed, and scientific guidance can be provided for environmental governance and pollution control. In the biomedical field, antimony isotope tracing technology provides a powerful tool for studying the metabolic processes of antimony in organisms. Antimony compounds possess certain pharmacological activities and are used to treat certain diseases, but they can also have toxic effects on the human body. By introducing antimony isotope-labeled compounds and tracking their absorption, distribution, metabolism, and excretion in organisms, we can gain a deeper understanding of the biological effects of antimony, providing important information for drug development and toxicity assessment. Antimony isotope standard materials are the foundation and core of antimony isotope research and analysis. In various tasks such as isotope tracing, environmental pollutant source tracing, and nuclear medicine research, accurate isotope ratio measurements are crucial for obtaining reliable experimental results.

[0003] Although antimony isotope standards have important applications in many fields, their development technology still faces numerous challenges and limitations, mainly in the hydrolysis and valence instability of antimony, as well as the poor stability of gradient concentration solutions. Antimony is prone to hydrolysis in acidic media (Sb 3+ →Sb(OH)3↓), causing antimony ions to precipitate from the solution, forming an insoluble precipitate. Simultaneously, antimony also undergoes a redox reaction in solution (Sb... 3+ Sb 5+ This instability in valence state can further lead to shifts in isotope ratios. For example, under acidic conditions, Sb 3+ It may be oxidized to Sb 5+ Under reducing conditions, Sb 5+ It may also be reduced to Sb 3+This change in valence state not only affects the chemical speciation of antimony but also leads to isotopic fractionation, making it impossible for the isotopic ratios of standard substances to remain stable over the long term. Poor stability of gradient concentration solutions refers to the tendency of traditionally prepared antimony isotope gradient concentration solutions (concentration range 0.1–1000 ng / g) to exhibit precipitation or isotopic fractionation after long-term storage (>2 years). This is mainly due to the lack of effective control over the chemical speciation of antimony, leading to the gradual hydrolysis or redox reactions of antimony ions in the solution, thus affecting the homogeneity and stability of the solution. For example, low-concentration antimony solutions (<10 ng / g) are more prone to loss due to adsorption or hydrolysis during storage, while high-concentration antimony solutions (>100 ng / g) may experience changes in isotopic ratios due to redox reactions.

[0004] Currently, the preparation of antimony isotope standards mainly relies on a single nitric acid medium and conventional stabilizers (such as tartaric acid and citric acid). These methods cannot effectively address the problems of antimony hydrolysis and valence instability. For example, while nitric acid can inhibit antimony hydrolysis to some extent, its acidic environment exacerbates redox reactions, leading to changes in antimony's valence state. Moreover, this oxidation gradually intensifies with prolonged storage, severely affecting the stability of the standards. While conventional stabilizers can form complexes with antimony, stabilizing its chemical form to some extent, these complexes may gradually decompose during long-term storage, causing antimony ions to be released again and continue undergoing hydrolysis or redox reactions. Therefore, their stabilizing effect is limited and cannot maintain the long-term stability of antimony's chemical form and isotope ratios. Thus, there is an urgent need to develop a method to improve the storage stability of antimony isotope standards to address the problems of antimony hydrolysis and valence instability. Summary of the Invention

[0005] To address the problem of poor storage stability of antimony isotope standard materials in existing technologies, this invention provides an antimony isotope standard solution, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a method for preparing an antimony isotope standard solution, comprising: Antimony isotope particles were dissolved in a mixed solution of aqua regia and hydrofluoric acid, and then dried to obtain solid antimony isotope material. The solid antimony isotope was diluted to volume with nitric acid solution to obtain a standard antimony isotope solution.

[0007] Optionally, in the mixed solution of aqua regia and hydrofluoric acid, the volume concentration of hydrofluoric acid is 0.05% to 0.2%.

[0008] Optionally, in the mixed solution of aqua regia and hydrofluoric acid, the volume concentration of hydrofluoric acid is 0.1%.

[0009] Optionally, it also includes a pretreatment process for antimony isotope particles, specifically: Antimony isotope particles were pretreated by cleaning them with supercritical carbon dioxide to remove oxides from their surface.

[0010] Optionally, the temperature for cleaning antimony isotope particles using supercritical carbon dioxide is 35℃~55℃, and the pressure is 8~10MPa.

[0011] Optionally, during the process of adjusting the volume of the antimony isotope solid material with nitric acid solution, a stabilizer is also added, wherein the stabilizer is a mixed solution of citric acid and thiourea.

[0012] Optionally, in the stabilizer, the concentration of citric acid is 0.5 to 1.2 mmol / L, and the molar ratio of citric acid to thiourea is 1:1.5 to 1:2.5.

[0013] An antimony isotope standard solution is prepared using the above-described method for preparing antimony isotope standard solutions.

[0014] Optionally, the antimony isotope standard solution storage container is a storage container with an inner wall covered by a hydrophobic silane film.

[0015] The above-mentioned antimony isotope standard solutions are used as tracer tools.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for preparing an antimony isotope standard solution. The method involves first dissolving antimony isotope particles in a mixed solution of aqua regia and hydrofluoric acid, then drying to obtain a solid antimony isotope substance. The solid antimony isotope substance is then diluted to volume with nitric acid solution to obtain the antimony isotope standard solution. This method cleverly utilizes aqua regia and hydrofluoric acid as the dissolution system, leveraging the hydrofluoric acid complexation of Sb... 3+ [SbF6] is formed. 3- It effectively inhibited Sb 3+ The hydrolysis-induced isotope ratio shift problem is addressed by the strong oxidizing properties of aqua regia, which ensures the complete conversion of Sb to Sb. 5+ This avoids valence fluctuations and achieves long-term stable preservation of antimony isotope standard solutions. Experimental studies have shown that after adjusting the dissolution system, the shelf life of antimony isotope standard solutions is extended from the conventional 2 years to 5 years (Δ). 123 Sb / 121 Sb < 0.005‰, antimony isotope ratio ( 123 Sb / 121The relative expanded uncertainty of Sb is ≤0.02‰ (k=2), thus achieving high stability, high homogeneity, and long-term reliability of antimony isotope standards. This effectively solves the problems of easy hydrolysis and unstable valence state in existing antimony isotope standard solutions.

[0017] In the mixed solution of aqua regia and hydrofluoric acid, the volume concentration of hydrofluoric acid is 0.05%–0.2%, preferably 0.1%. By precisely controlling the amount of hydrofluoric acid, multiple optimizations are achieved in the dissolution, complexation, and stability of antimony isotopes, effectively inhibiting Sb. 3+ The hydrolysis reaction.

[0018] Antimony isotope particles readily react with oxygen during storage or processing to form antimony oxide. The dissolution rate of antimony oxide is much lower than that of metallic antimony, leading to incomplete dissolution and affecting the accuracy of solution concentration. Furthermore, the antimony isotope ratios in the oxide may differ from those in metallic antimony, contaminating the isotopic composition of the standard solution. To avoid these problems, the preparation method of the antimony isotope standard solution also includes a pretreatment process for the antimony isotope particles. Supercritical carbon dioxide washing is introduced as a pretreatment step for the antimony isotope particles, which can efficiently remove oxides from the particle surface, significantly improving subsequent dissolution efficiency and the accuracy of isotope ratios.

[0019] During the process of adjusting the volume of the antimony isotope solid with nitric acid solution, a stabilizer is added. The stabilizer is a mixed solution of citric acid and thiourea. The addition of the stabilizer further improves the long-term stability of the antimony isotope standard solution and suppresses isotope ratio drift. Citric acid contains three carboxyl groups and one hydroxyl group, which can react with Sb. 3+ Formation of five-membered ring chelates effectively inhibits Sb 3+ Hydrolysis is involved. Furthermore, it can preferentially adsorb onto the inner walls of containers (such as glass and polyethylene) to form a protective film, preventing the adsorption of antimony and further enhancing the stability of the antimony isotope standard solution. Thiourea can block Sb... 5+ With Sb 3+ The disproportionation reaction further stabilizes the antimony isotope ratio, mainly through a synergistic stabilizing effect with citric acid.

[0020] This invention provides an antimony isotope standard solution, prepared using the aforementioned method. This antimony isotope standard solution exhibits good isotope fidelity, long-term stability, analytical precision, and environmental adaptability, providing crucial technical support for high-precision isotope analysis in fields such as geology, environment, and nuclear safety.

[0021] The antimony isotope standard solution storage container is a storage container with an inner wall coated with a hydrophobic silane film. The hydrophobic silane film can firmly adhere to the inner wall of the container (glass, polyethylene, etc.), exhibiting strong hydrophobicity. The densely packed -CH3 groups form a physical barrier that prevents Sb from entering the container. 3+ / Sb5+ The inability to access the silanol adsorption site, and the fact that the -CH3 group is a nonpolar group that does not interact with polar antimony ions, further achieves long-term stability, low isotope ratio deviation, and high analytical repeatability of antimony isotope standard solutions.

[0022] The aforementioned antimony isotope standard solution is used as a tracer tool. Due to its superior long-term stability, this antimony isotope standard solution can be widely applied as a tracer tool in fields such as geology, environment, and nuclear safety to ensure the accuracy, timeliness, and environmental friendliness of tracer results. It provides key technical support for scientific research and industrial applications, and has broad market prospects and social value. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the preparation method of an antimony isotope standard solution according to the present invention. Detailed Implementation

[0024] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0025] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0026] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0027] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0028] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0030] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0031] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0032] This invention discloses a method for preparing an antimony isotope standard solution, referring to... Figure 1 ,include: S1: Antimony isotope particles were dissolved in a mixed solution of aqua regia and hydrofluoric acid, and dried to obtain solid antimony isotope material, specifically: Pretreatment of antimony isotope particles: At a temperature of 35℃~55℃ and a pressure of 8~10MPa, supercritical carbon dioxide is used to clean the antimony isotope particles to remove oxides on the surface of the antimony isotope particles, thus completing the pretreatment of the antimony isotope particles. Preparation of a mixed solution of aqua regia and hydrofluoric acid: Hydrofluoric acid is added to aqua regia to obtain a mixed solution of aqua regia and hydrofluoric acid. In the mixed solution of aqua regia and hydrofluoric acid, the volume concentration of hydrofluoric acid is 0.05% to 0.2%, preferably 0.1%; the aqua regia is a mixed acid of nitric acid and hydrochloric acid in a volume ratio of 3:1. The pretreated antimony isotope particles were added to a mixed solution of aqua regia and hydrofluoric acid, and microwave-assisted digestion was carried out at 150℃~180℃ for 20~40 min. The mixture was then evaporated to dryness under constant temperature water bath conditions of 55℃~60℃ to obtain solid antimony isotope material.

[0033] S2: The solid antimony isotope material is diluted to volume with nitric acid solution to obtain an antimony isotope standard solution. Specifically, the solid antimony isotope material is dissolved in nitric acid solution with a volume concentration of 15%, and the volume is diluted according to the required antimony isotope concentration gradient to obtain an antimony isotope standard solution.

[0034] Optionally, during the process of adjusting the volume of the antimony isotope solid material with nitric acid solution, a stabilizer is also added. The stabilizer is a mixed solution of citric acid and thiourea; the concentration of citric acid in the stabilizer is 0.5–1.2 mmol / L, and the molar ratio of citric acid to thiourea is 1:1.5–1:2.5. The amount of stabilizer added is determined based on the potential requirement.

[0035] An online ORP sensor was used to monitor the potential of the antimony isotope standard solution in real time. The potential of the solution system was stabilized to +150 mV by adding 0.05% ascorbic acid. Then, the concentration of antimony isotopes in the antimony isotope standard solution was designed using the response surface methodology (RSM). The solution was then dispensed into high-density polyethylene (HDPE) containers with a hydrophobic silane film formed on the container walls for storage, 5 mL / bottle, and stored in a constant temperature environment of 20°C in the dark. The method for attaching the hydrophobic silane film to the inner wall of the HDPE container was as follows: the HDPE container was immersed in a 0.1% solution of 3-aminopropyltriethoxysilane and then dried by nitrogen purging, resulting in a HDPE container with a hydrophobic silane film formed on the container wall.

[0036] The gradient concentration range of antimony isotopes in the antimony isotope standard solution is 0.1 ng / g to 1000 ng / g.

[0037] This scheme cleverly selects aqua regia and hydrofluoric acid as the dissolving system, utilizing the hydrofluoric acid to complex Sb. 3+ [SbF6] is formed. 3- It effectively inhibited Sb 3+ The hydrolysis-induced isotope ratio shift problem is addressed by the strong oxidizing properties of aqua regia, which ensures the complete conversion of Sb to Sb. 5+ This avoids valence fluctuations and achieves long-term stable preservation of antimony isotope standard solutions. Experimental studies have shown that after adjusting the dissolution system, the shelf life of antimony isotope standard solutions is extended from the conventional 2 years to 5 years (Δ). 123 Sb / 121 Sb < 0.005‰, antimony isotope ratio ( 123 Sb / 121 The relative expanded uncertainty of Sb is ≤0.02‰ (k=2), thus achieving high stability, high homogeneity, and long-term reliability of antimony isotope standards. This effectively solves the problems of easy hydrolysis and unstable valence state in existing antimony isotope standard solutions.

[0038] Example 1 Hydrofluoric acid was added to the aqua regia to obtain a mixed solution of aqua regia and hydrofluoric acid. The volume concentration of hydrofluoric acid in the mixed solution was 0.1% (v / v). The aqua regia was a mixture of nitric acid and hydrochloric acid in a volume ratio of 3:1. High-purity antimony isotope particles (purity 99.999%) were cleaned with supercritical carbon dioxide at a temperature of 40℃ and a pressure of 10MPa to remove oxides from the surface of the antimony isotope particles, thus obtaining cleaned antimony isotope particles. The cleaned antimony isotope particles were added to a mixed solution of aqua regia and hydrofluoric acid, and microwave-assisted digestion was carried out at 180°C for 30 minutes. Then, the solution was evaporated to dryness in a constant temperature water bath at 60°C to obtain solid antimony isotope material. The solid antimony isotope material was dissolved in 15% nitric acid solution and the volume was adjusted to obtain antimony isotope standard solution. A stabilizer, comprising water, was added to an antimony isotope standard solution containing dissolved citric acid and thiourea. The concentration of citric acid was 1.5 mmol / L and the concentration of thiourea was 0.8 mmol / L. The solution potential was monitored in real time using an online ORP sensor, and the potential of the solution system was stabilized to +150 mV by adding 0.05% ascorbic acid. The concentration of antimony isotope in the antimony isotope standard solution was then designed using response surface methodology (RSM). The solution was dispensed into high-density polyethylene (HDPE) containers with a hydrophobic silane film formed on the container wall, 5 mL / bottle, and stored at a constant temperature of 20°C in the dark. The antimony isotope standard solutions contain gradient concentrations of 0.1 ng / g, 1 ng / g, 10 ng / g, 50 ng / g, 100 ng / g, 200 ng / g, 500 ng / g, 800 ng / g, and 1000 ng / g, which are precisely weighed and diluted using a 1 / 1,000,000 ng / g balance (ME5-F).

[0039] Example 2 Hydrofluoric acid was added to the aqua regia to obtain a mixed solution of aqua regia and hydrofluoric acid. The volume concentration of hydrofluoric acid in the mixed solution was 0.1% (v / v). The aqua regia was a mixture of nitric acid and hydrochloric acid in a volume ratio of 3:1. High-purity antimony isotope particles (purity 99.999%) were cleaned with supercritical carbon dioxide at a temperature of 40℃ and a pressure of 10MPa to remove oxides from the surface of the antimony isotope particles, thus obtaining cleaned antimony isotope particles. The cleaned antimony isotope particles were added to a mixed solution of aqua regia and hydrofluoric acid, and microwave-assisted digestion was carried out at 180°C for 30 minutes. Then, the solution was evaporated to dryness in a constant temperature water bath at 60°C to obtain solid antimony isotope material. The solid antimony isotope material was dissolved in 15% nitric acid solution and the volume was adjusted to obtain antimony isotope standard solution. A stabilizer, comprising water containing citric acid dissolved in it, was added to an antimony isotope standard solution. The concentration of citric acid was 1.5 mmol / L. The solution potential was monitored in real time using an online ORP sensor. The potential of the solution system was stabilized to +150 mV by adding 0.05% ascorbic acid. The concentration of antimony isotope in the antimony isotope standard solution was then designed using response surface methodology (RSM). The solution was dispensed into high-density polyethylene containers with a hydrophobic silane film formed on the container wall, 5 mL / bottle, and stored at a constant temperature of 20°C in the dark. The antimony isotope standard solutions contain gradient concentrations of 0.1 ng / g, 1 ng / g, 10 ng / g, 50 ng / g, 100 ng / g, 200 ng / g, 500 ng / g, 800 ng / g, and 1000 ng / g, which are precisely weighed and diluted using a 1 / 1,000,000 ng / g balance (ME5-F).

[0040] Example 3 Hydrofluoric acid was added to the aqua regia to obtain a mixed solution of aqua regia and hydrofluoric acid. The volume concentration of hydrofluoric acid in the mixed solution was 0.1% (v / v). The aqua regia was a mixture of nitric acid and hydrochloric acid in a volume ratio of 3:1. High-purity antimony isotope particles (purity 99.999%) were cleaned with supercritical carbon dioxide at a temperature of 40℃ and a pressure of 10MPa to remove oxides from the surface of the antimony isotope particles, thus obtaining cleaned antimony isotope particles. The cleaned antimony isotope particles were added to a mixed solution of aqua regia and hydrofluoric acid, and microwave-assisted digestion was carried out at 180°C for 30 minutes. Then, the solution was evaporated to dryness in a constant temperature water bath at 60°C to obtain solid antimony isotope material. The solid antimony isotope material was dissolved in 15% nitric acid solution and the volume was adjusted to obtain antimony isotope standard solution. A stabilizer, comprising water containing dissolved thiourea at a concentration of 0.8 mmol / L, was added to an antimony isotope standard solution. The solution potential was monitored in real time using an online ORP sensor, and the potential of the solution system was stabilized to +150 mV by adding 0.05% ascorbic acid. The concentration of antimony isotope in the antimony isotope standard solution was then designed using response surface methodology (RSM). The solution was dispensed into high-density polyethylene containers with a hydrophobic silane film formed on the container wall, 5 mL / bottle, and stored at a constant temperature of 20°C in the dark. The antimony isotope standard solutions contain gradient concentrations of 0.1 ng / g, 1 ng / g, 10 ng / g, 50 ng / g, 100 ng / g, 200 ng / g, 500 ng / g, 800 ng / g, and 1000 ng / g, which are precisely weighed and diluted using a 1 / 1,000,000 ng / g balance (ME5-F).

[0041] Example 4 Hydrofluoric acid was added to the aqua regia to obtain a mixed solution of aqua regia and hydrofluoric acid. The volume concentration of hydrofluoric acid in the mixed solution was 0.1% (v / v). The aqua regia was a mixture of nitric acid and hydrochloric acid in a volume ratio of 3:1. High-purity antimony isotope particles (purity 99.999%) were cleaned with supercritical carbon dioxide at a temperature of 40℃ and a pressure of 10MPa to remove oxides from the surface of the antimony isotope particles, thus obtaining cleaned antimony isotope particles. The cleaned antimony isotope particles were added to a mixed solution of aqua regia and hydrofluoric acid, and microwave-assisted digestion was carried out at 180°C for 30 minutes. Then, the solution was evaporated to dryness in a constant temperature water bath at 60°C to obtain solid antimony isotope material. The solid antimony isotope material was dissolved in 15% nitric acid solution and the volume was adjusted to obtain antimony isotope standard solution. The solution potential was monitored in real time using an online ORP sensor, and the potential of the solution system was stabilized to +150 mV by adding 0.05% ascorbic acid. Then, the concentration of antimony isotopes in the antimony isotope standard solution was designed using the response surface methodology (RSM). The solutions were dispensed into high-density polyethylene (HDPE) containers with a hydrophobic silane film on the container wall, 5 mL / bottle, and stored in a constant temperature environment of 20℃ away from light. The antimony isotope standard solutions contain gradient concentrations of 0.1 ng / g, 1 ng / g, 10 ng / g, 50 ng / g, 100 ng / g, 200 ng / g, 500 ng / g, 800 ng / g, and 1000 ng / g, which are precisely weighed and diluted using a 1 / 1,000,000 ng / g balance (ME5-F).

[0042] Example 5 Hydrofluoric acid was added to the aqua regia to obtain a mixed solution of aqua regia and hydrofluoric acid. The volume concentration of hydrofluoric acid in the mixed solution was 0.1% (v / v). The aqua regia was a mixture of nitric acid and hydrochloric acid in a volume ratio of 3:1. High-purity antimony isotope particles (purity 99.999%) were cleaned with supercritical carbon dioxide at a temperature of 40℃ and a pressure of 10MPa to remove oxides from the surface of the antimony isotope particles, thus obtaining cleaned antimony isotope particles. The cleaned antimony isotope particles were added to a mixed solution of aqua regia and hydrofluoric acid, and microwave-assisted digestion was carried out at 180°C for 30 minutes. Then, the solution was evaporated to dryness in a constant temperature water bath at 60°C to obtain solid antimony isotope material. The solid antimony isotope material was dissolved in 15% nitric acid solution and the volume was adjusted to obtain antimony isotope standard solution. A stabilizer, comprising water, was added to an antimony isotope standard solution containing dissolved citric acid and thiourea. The concentration of citric acid was 1.5 mmol / L and the concentration of thiourea was 0.8 mmol / L. The solution potential was monitored in real time using an online ORP sensor, and the potential of the solution system was stabilized to +150 mV by adding 0.05% ascorbic acid. The concentration of antimony isotope in the antimony isotope standard solution was then designed using response surface methodology (RSM). The solution was dispensed into untreated high-density polyethylene (HDPE) containers, 5 mL / bottle, and stored at a constant temperature of 20°C, protected from light. The antimony isotope standard solutions contain gradient concentrations of 0.1 ng / g, 1 ng / g, 10 ng / g, 50 ng / g, 100 ng / g, 200 ng / g, 500 ng / g, 800 ng / g, and 1000 ng / g, which are precisely weighed and diluted using a 1 / 1,000,000 ng / g balance (ME5-F).

[0043] Comparative Example 1 Aqua regia is prepared by mixing nitric acid and hydrochloric acid in a volume ratio of 1:3. High-purity antimony isotope particles (purity 99.999%) were cleaned with supercritical carbon dioxide at a temperature of 40℃ and a pressure of 10MPa to remove oxides from the surface of the antimony isotope particles, thus obtaining cleaned antimony isotope particles. The cleaned antimony isotope particles were added to a mixed solution of aqua regia and hydrofluoric acid, and microwave-assisted digestion was carried out at 180°C for 30 minutes. Then, the solution was evaporated to dryness in a constant temperature water bath at 60°C to obtain solid antimony isotope material. The solid antimony isotope material was dissolved in 15% nitric acid solution and the volume was adjusted to obtain antimony isotope standard solution. The potential of the solution system was stabilized to +150 mV by adding 0.05% ascorbic acid. Then, the concentration of antimony isotopes in the antimony isotope standard solution was designed by response surface methodology (RSM). The solutions were dispensed into untreated high-density polyethylene containers, 5 mL / bottle, and stored in a constant temperature environment of 20°C away from light. The antimony isotope standard solutions contain gradient concentrations of 0.1 ng / g, 1 ng / g, 10 ng / g, 50 ng / g, 100 ng / g, 200 ng / g, 500 ng / g, 800 ng / g, and 1000 ng / g, which are precisely weighed and diluted using a 1 / 1,000,000 ng / g balance (ME5-F).

[0044] Comparative Example 2 Aqua regia is prepared by mixing nitric acid and hydrochloric acid in a volume ratio of 1:3. High-purity antimony isotope particles (purity 99.999%) were cleaned with supercritical carbon dioxide at a temperature of 40℃ and a pressure of 10MPa to remove oxides from the surface of the antimony isotope particles, thus obtaining cleaned antimony isotope particles. The cleaned antimony isotope particles were added to a mixed solution of aqua regia and hydrofluoric acid, and microwave-assisted digestion was carried out at 180°C for 30 minutes. Then, the solution was evaporated to dryness in a constant temperature water bath at 60°C to obtain solid antimony isotope material. The solid antimony isotope material was dissolved in 15% nitric acid solution and the volume was adjusted to obtain antimony isotope standard solution. A stabilizer, comprising water, was added to an antimony isotope standard solution containing citric acid and thiourea dissolved in it. The concentration of citric acid was 1.5 mmol / L and the concentration of thiourea was 0.8 mmol / L. The solution potential was monitored in real time using an online ORP sensor, and the potential of the solution system was stabilized to +150 mV by adding 0.05% ascorbic acid. Then, the concentration of antimony isotope in the antimony isotope standard solution was designed using response surface methodology (RSM). The solution was dispensed into high-density polyethylene containers with a hydrophobic silane film formed on the container wall, 5 mL / bottle, and stored in a constant temperature environment of 20°C, protected from light. The antimony isotope standard solutions contain gradient concentrations of 0.1 ng / g, 1 ng / g, 10 ng / g, 50 ng / g, 100 ng / g, 200 ng / g, 500 ng / g, 800 ng / g, and 1000 ng / g, which are precisely weighed and diluted using a 1 / 1,000,000 ng / g balance (ME5-F).

[0045] To further illustrate the beneficial effects of the technical solution of the present invention, the solubility of antimony isotope particles and the antimony isotope standard solution Sb were tested in the above embodiments and comparative examples. 5+ The tests included percentage (%) test, stabilizer test, container passivation effect test, and antimony adsorption rate test. The test conditions for the antimony isotope particle dissolution rate test were as follows: the particles were placed in a Class 100 cleanroom fume hood, and the dissolution was observed by controlling the time. Antimony isotope standard solution Sb 5+ The percentage (%) test conditions are: test redox environment; The stabilizer test conditions are as follows: controlled variables, comparing the addition and no addition under the same environment; The conditions for container passivation effect test and antimony adsorption rate test are: long-term storage at 3℃ and monthly testing, observing changes in solution concentration and isotope ratio; The test results are shown in the table below:

[0046] The results above show that, compared to Comparative Example 2, the synergistic effect of hydrofluoric acid and aqua regia in the dissolution system can significantly improve the stability of the antimony solution. Compared to Comparative Example 1, the particle solubility and solution stability of Examples 1-5 are improved to varying degrees, indicating that the combination of aqua regia and hydrofluoric acid has certain advantages in dissolving Sb solid particles. At the same time, the complexation reaction of hydrofluoric acid can help stabilize Sb in the solution and reduce the loss caused by hydrolysis. Among them, Example 1 is superior to other examples in terms of both long-term stability and concentration loss ratio, indicating that the use of citric acid and thiourea as stabilizers, and the use of a hydrophobic membrane to treat the inner wall of the storage container, can effectively enhance the long-term stability of the standard solution and reduce the changes in concentration and isotopic composition caused by container adsorption and self-hydrolysis.

[0047] This invention provides an antimony isotope standard solution, prepared using the aforementioned method. This antimony isotope standard solution exhibits good isotope fidelity, long-term stability, analytical precision, and environmental adaptability, providing crucial technical support for high-precision isotope analysis in fields such as geology, environment, and nuclear safety.

[0048] The antimony isotope standard solution storage container is a storage container with an inner wall coated with a hydrophobic silane film. The hydrophobic silane film can firmly adhere to the inner wall of the container (glass, polyethylene, etc.), exhibiting strong hydrophobicity. The densely packed -CH3 groups form a physical barrier that prevents Sb from entering the container. 3+ / Sb 5+ The inability to access the silanol adsorption site, and the fact that the -CH3 group is a nonpolar group that does not interact with polar antimony ions, further achieves long-term stability, low isotope ratio deviation, and high analytical repeatability of antimony isotope standard solutions.

[0049] The aforementioned antimony isotope standard solution is used as a tracer tool. Due to its superior long-term stability, this antimony isotope standard solution can be widely applied as a tracer tool in fields such as geology, environment, and nuclear safety to ensure the accuracy, timeliness, and environmental friendliness of tracer results. It provides key technical support for scientific research and industrial applications, and has broad market prospects and social value.

[0050] In summary, this invention provides an antimony isotope standard solution, its preparation method, and its application. By cleverly selecting aqua regia and hydrofluoric acid as the dissolution system, hydrofluoric acid complexes Sb. 3+ [SbF6] is formed. 3- It effectively inhibited Sb 3+ The hydrolysis-induced isotope ratio shift problem is addressed by the strong oxidizing properties of aqua regia, which ensures the complete conversion of Sb to Sb. 5+This avoids valence fluctuations and enables long-term stable preservation of antimony isotope standard solutions. It effectively solves the problems of easy hydrolysis and unstable valence of existing antimony isotope standard solutions, and has great potential for widespread application in the field of sensor technology.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A method for preparing an antimony isotope standard solution, characterized in that, include: Antimony isotope particles were dissolved in a mixed solution of aqua regia and hydrofluoric acid, and then dried to obtain solid antimony isotope material; the volume concentration of hydrofluoric acid in the mixed solution of aqua regia and hydrofluoric acid was 0.05% to 0.2%; The solid antimony isotope material was diluted to volume with nitric acid solution to obtain an antimony isotope standard solution. During the dilution process, a stabilizer was added, which was a mixed solution of citric acid and thiourea. The concentration of citric acid in the stabilizer was 0.5–1.2 mmol / L, and the molar ratio of citric acid to thiourea was 1:1.5–1:2.

5.

2. The method for preparing the antimony isotope standard solution according to claim 1, characterized in that, In the mixed solution of aqua regia and hydrofluoric acid, the volume concentration of hydrofluoric acid is 0.1%.

3. The method for preparing the antimony isotope standard solution according to claim 1, characterized in that, It also includes a pretreatment process for antimony isotope particles, specifically: Antimony isotope particles were pretreated by cleaning them with supercritical carbon dioxide to remove oxides from their surface.

4. The method for preparing the antimony isotope standard solution according to claim 3, characterized in that, The temperature for cleaning antimony isotope particles using supercritical carbon dioxide is 35℃~55℃, and the pressure is 8~10MPa.

5. A standard solution of antimony isotopes, characterized in that, Prepared using the method for preparing antimony isotope standard solutions according to any one of claims 1-4.

6. The antimony isotope standard solution according to claim 5, characterized in that, The antimony isotope standard solution storage container is a storage container with a hydrophobic silane film covering the inner wall.

7. The application of the antimony isotope standard solution according to claim 5 as a tracer tool.

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