Antimony isotope standard solution, preparation method and application

Abstract

The invention relates to the technical field of isotope solution storage, in particular to an antimony isotope standard solution and a preparation method and application thereof.The method comprises the steps that antimony isotope particles are dissolved in a mixed solution of reverse aqua regia and hydrofluoric acid and dried, and an antimony isotope solid matter is obtained; reverse aqua regia and hydrofluoric acid are ingeniously selected as a dissolving system, Sb < 3 + > is complexed by hydrofluoric acid to form [SbF6] < 3->, the problem of isotope ratio drift caused by Sb < 3 + > hydrolysis is effectively inhibited, the strong oxidizing property of the reverse aqua regia ensures that Sb is completely converted into Sb < 5 + >, and the content of the Sb < 5 + > is increased. Therefore, valence fluctuation is avoided, long-term stable preservation of the antimony isotope standard solution is achieved, and the problems that an existing antimony isotope standard solution is prone to hydrolysis and unstable in valence are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of isotope solution storage, in particular to a standard antimony isotope solution, a preparation method and application thereof. BACKGROUND

[0002] As an important metal element, antimony (Sb) exists in multiple isotopes in nature. The isotope composition of antimony changes regularly in different geological processes, environmental changes and biological metabolic processes, which makes antimony isotope a powerful tracer. In the field of geology, antimony isotope can be used to study the process of mineralization. By analyzing the ratio of antimony isotope in antimony ore and related rocks, the source of ore-forming material can be traced, the evolution process of ore-forming fluid and the mechanism of mineralization can be understood, and important basis can be provided for geological exploration and mineral resource evaluation. In environmental science, antimony isotope plays a key role in the tracing of environmental pollutants. Different pollution sources emit antimony-containing substances with different antimony isotope characteristics. By measuring the ratio of antimony isotope in the environment, the source of pollutants can be accurately identified, and the influence of different pollution sources on the environment can be evaluated, providing scientific guidance for environmental governance and pollution prevention and control. In the field of biomedicine, antimony isotope tracing technology provides a powerful means for studying the metabolic process of antimony in the body. Antimony compounds have certain pharmacological activity and are used to treat some diseases, but they may also have toxic effects on the human body. By introducing antimony isotope labeled compounds, the absorption, distribution, metabolism and excretion of the compounds in the body can be tracked, and the biological effect mechanism of antimony can be understood in depth, providing important information for drug research and development and toxicity evaluation. Among them, antimony isotope standard substance is the basis and core of antimony isotope research and analysis. In isotope tracing, environmental pollutant tracing and nuclear medicine research, accurate isotope ratio measurement is the key to obtaining reliable experimental results.

[0003] Although antimony isotope standard substance has important application value in many fields, its development technology still faces many challenges and limitations, mainly in the aspects of hydrolysis and unstable valence of antimony element and poor stability of gradient concentration solution. Antimony element is easy to hydrolyze in acidic medium (Sb 3+ →Sb(OH)3↓), which leads to the precipitation of antimony ions from the solution to form insoluble precipitates. At the same time, antimony element also has redox reaction in solution (Sb 3+ Sb 5+ ), which further leads to the drift of isotope ratio. For example, Sb 3+ may be oxidized to Sb 5+ under acidic conditions, and Sb 5+ may be reduced to Sb 3+The valence state change not only affects the chemical form of antimony, but also causes isotopic fractionation, so that the isotopic ratio of the standard substance cannot be kept stable for a long time. The poor stability of the gradient concentration solution refers to that the antimony isotope gradient concentration solution (concentration range: 0.1-1000 ng / g) prepared by the traditional method is prone to precipitation or isotopic fractionation after long-term storage (>2 years), which is mainly due to the lack of effective regulation of the chemical form of antimony, causing the antimony ions in the solution to gradually undergo hydrolysis or redox reaction, thereby affecting the uniformity and stability of the solution. For example, low-concentration antimony solution (<10 ng / g) is more likely to be lost due to adsorption or hydrolysis during storage, while high-concentration antimony solution (>100 ng / g) may cause changes in isotopic ratio due to redox reaction.

[0004] At present, the preparation of antimony isotope standard substance mainly relies on single nitric acid medium and conventional stabilizers (such as tartaric acid, citric acid, etc.). These methods cannot effectively solve the problems of hydrolysis and unstable valence state of antimony. For example, although the nitric acid medium can inhibit the hydrolysis of antimony to a certain extent, the acidic environment will exacerbate the redox reaction of antimony, causing the valence state of antimony to change, and with the extension of storage time, the oxidation will gradually intensify, seriously affecting the stability of the standard substance; and the conventional stabilizer can form a complex with antimony to a certain extent, thereby stabilizing the chemical form of antimony, but during long-term storage, the complex may gradually decompose, causing the release of antimony ions, which continue to undergo hydrolysis or redox reaction, and the stabilizing effect is limited, and the chemical form and isotopic ratio of antimony cannot be maintained for a long time. Therefore, it is urgent to develop a method for improving the storage stability of antimony isotope standard substance to solve the problems of hydrolysis and unstable valence state of antimony. SUMMARY

[0005] In view of the poor storage stability of the antimony isotope standard substance in the prior art, the application provides an antimony isotope standard solution, a preparation method and application.

[0006] To achieve the above-mentioned purpose, the application adopts the following technical solutions: The application provides a preparation method of an antimony isotope standard solution, comprising: dissolving antimony isotope particles in a mixed solution of reverse aqua regia and hydrofluoric acid, drying to obtain antimony isotope solid substance; using a nitric acid solution to make up the volume of the antimony isotope solid substance to obtain an antimony isotope standard solution.

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

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

[0009] Optionally, the method further comprises a pretreatment process of the antimony isotope particles, specifically: The antimony isotope particles are cleaned by supercritical carbon dioxide to remove oxides on the surface of the antimony isotope particles, and the pretreatment of the antimony isotope particles is completed.

[0010] Optionally, the temperature for cleaning the antimony isotope particles by supercritical carbon dioxide is 35-55 DEG C, and the pressure is 8-10 MPa.

[0011] Optionally, during the process of making the antimony isotope solid substance constant volume by using nitric acid solution, a stabilizer is further added, and the stabilizer is a mixed solution of citric acid and thiocarbamide.

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

[0013] An antimony isotope standard solution is prepared by using the preparation method of the antimony isotope standard solution.

[0014] Optionally, the storage container of the antimony isotope standard solution is a storage container with a hydrophobic silane membrane on the inner wall.

[0015] The antimony isotope standard solution is used as a tracing tool.

[0016] Compared with the prior art, the present application has the following beneficial effects: The present application provides a preparation method of an antimony isotope standard solution, which comprises the following steps: dissolving antimony isotope particles in a mixed solution of reverse aqua regia and hydrofluoric acid, drying to obtain antimony isotope solid substance, and making the antimony isotope solid substance constant volume by using nitric acid solution to obtain the antimony isotope standard solution. 3+ [SbF6] 3- , effectively inhibits the problem of isotope ratio drift caused by hydrolysis of Sb 3+ , and 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 long-term stable storage of the antimony isotope standard solution. 123 Sb / 121 Sb<0.005‰), the 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 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).

[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 solid antimony isotope was diluted to volume with nitric acid solution to obtain a standard antimony isotope solution.

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 0.05% to 0.2%.

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

4. 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.

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

6. The method for preparing the antimony isotope standard solution according to claim 1, characterized in that, During the process of adjusting the volume of the antimony isotope solid material with nitric acid solution, a stabilizer is also added, which is a mixed solution of citric acid and thiourea.

7. The method for preparing the antimony isotope standard solution according to claim 6, characterized in that, In the stabilizer, the concentration of citric acid is 0.5–1.2 mmol / L, and the molar ratio of citric acid to thiourea is 1:1.5–1:2.

5.

8. 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 1-7.

9. The antimony isotope standard solution according to claim 8, characterized in that, The antimony isotope standard solution storage container is a storage container with a hydrophobic silane film covering the inner wall.

10. The application of the antimony isotope standard solution according to claim 8 as a tracer tool.

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