Separation method of Sr-Nd-Hf and isotope analysis method of Sr, Nd and Hf

Abstract

The present application relates to a Sr-Nd-Hf separation method and a Sr, Nd, and Hf isotope analysis method. The separation method comprises: dissolving a geological sample to obtain 10-12 mol / L HNO 3 The sample solution of the medium; the content of Sr and / or Nd in the sample solution is tested, and the sample solution is divided into a high-content sample or a low-content sample; if the sample solution is a high-content sample, it is divided into three parts, and SR leaching resin mini exchange column, DGA leaching resin mini exchange column, and UTEVA leaching resin mini exchange column are used for analysis respectively; if the sample solution is a low-content sample, a set of columns formed by UTEVA leaching resin mini exchange column, SR leaching resin mini exchange column, and DGA leaching resin mini exchange column from top to bottom is used for analysis to obtain an element analysis solution. The overall process of this application is extremely simple, which reduces the complexity of Sr, Nd and Hf separation and simplifies the overall process.

Description

Technical Field

[0001] The present application relates to the technical fields of chemical analysis, isotope geochemistry and isotope geochronology, and in particular to a Sr-Nd-Hf separation method and a Sr, Nd and Hf isotope analysis method. Background Art

[0002] Rb-Sr, Sm-Nd and Lu-Hf isotope systems are widely used in geochemistry, cosmochemistry and environmental science. The analysis of Sr, Nd and Hf isotopes first requires the separation of high-purity Sr, Nd and Hf from geological samples, and then the determination by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS).

[0003] Due to the differences in the chemical properties of Sr, Nd and Hf, the current processes for separating these three elements are relatively complex and time-consuming. Summary of the invention

[0004] To solve the above problems, the present application provides a Sr-Nd-Hf separation method and a Sr, Nd, and Hf isotope analysis method to overcome or at least partially overcome the deficiencies of the prior art.

[0005] In a first aspect, the present application provides a method for separating Sr-Nd-Hf, the method comprising:

[0006] Sample dissolution step: dissolve the geological sample to obtain a sample solution in 10-12 mol / L HNO3 medium;

[0007] Sample classification step: testing the content of Sr and / or Nd in the sample solution, and classifying the sample solution into a high-content sample or a low-content sample;

[0008] Chemical separation step: If the sample solution is a high-content sample, it is divided into three parts, and analyzed using SR leaching resin mini exchange column, DGA leaching resin mini exchange column, and UTEVA leaching resin mini exchange column respectively; if the sample solution is a low-content sample, it is analyzed using a set of columns formed from top to bottom by UTEVA leaching resin mini exchange column, SR leaching resin mini exchange column, and DGA leaching resin mini exchange column to obtain elemental analysis solutions of Sr, Nd, and Hf.

[0009] Optionally, in the above-mentioned Sr-Nd-Hf separation method, the sample dissolution step specifically includes:

[0010] First dissolution step: add 1-4mL 27mol / L HF and 1-4mL 15mol / L HNO3 to 50-300mg geological sample in sequence for dissolution, and keep at 150-200℃ for 5-7 days for digestion;

[0011] Second dissolution step: evaporate to wet salt state at 100-130°C, then add 0.5-2mL 27mol / L HF and 0.5-2mL 15mol / L HNO3 in sequence to dissolve, and keep warm at 100-130°C for 24-36 hours to digest;

[0012] The third dissolution step: evaporate to wet salt at 100-130°C, and then digest twice with 0.5-2mL 15mol / LHNO3;

[0013] Fourth dissolution step: add 2-5 mL of saturated boric acid solution and evaporate to dryness at 100-130°C to eliminate residual HF during sample digestion;

[0014] The fifth dissolution step: add 3-5 mL 10-12 mol / L HNO3 to dissolve the sample, keep warm at 100-130°C for 4-6 hours to obtain a sample solution dissolved in 10-12 mol / L HNO3.

[0015] Optionally, in the above-mentioned Sr-Nd-Hf separation method, if the sample solution is a high-content sample, SR leaching resin mini exchange column, DGA leaching resin mini exchange column, and UTEVA leaching resin mini exchange column are used for analysis, respectively, including:

[0016] dividing the high-content sample into a first part, a second part, and a third part;

[0017] The first part is loaded onto the SR leaching resin mini exchange column for elution, and then analyzed using 0.45 mol / L HNO3 to obtain an elemental analysis solution of Sr;

[0018] The second part is loaded onto the DGA leaching resin mini exchange column for elution, and then eluted with 2.6 mol / L HCl and analyzed with 1.8 mol / L HCl in sequence to obtain an elemental analysis solution of Nd;

[0019] The third part was loaded onto the UTEVA leaching resin mini exchange column for elution, and then analyzed using 4.5 mol / L HNO3 to obtain an elemental analysis solution of Hf.

[0020] Optionally, in the above-mentioned Sr-Nd-Hf separation method, the SR leaching resin mini exchange column is prepared by filling 1±0.1 mL of 50-100 μm SR leaching resin in a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end;

[0021] The UTEVA leaching resin mini exchange column is prepared by filling 1±0.1 mL of 50-100 μm UTEVA leaching resin into a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end;

[0022] The DGA leaching resin mini exchange column is prepared by uniformly mixing 0.5±0.1 mL 50-100 μm and 0.5±0.1 mL 100-200 μm DGA leaching resin and then filling the mixture into a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end.

[0023] Optionally, in the above-mentioned Sr-Nd-Hf separation method, the step of loading the first part onto the SR leaching resin mini exchange column for elution specifically comprises:

[0024] The SR leaching resin mini exchange column is pre-cleaned with 10-20 mL 0.05 mol / L HCl and 10-30 mL high-purity water in sequence;

[0025] Add 3-5 mL 10-12 mol / L HNO3 to the SR leaching resin mini exchange column for equilibrium;

[0026] The first part is diluted to 3-5 mL with 10-12 mol / L HNO3 and then loaded into the SR leaching resin mini exchange column;

[0027] Use 3-6mL 10-12mol / LHNO3 to elute the matrix elements and the interfering element Rb of Sr.

[0028] Optionally, in the above-mentioned Sr-Nd-Hf separation method, the step of loading the second part onto the DGA leaching resin mini exchange column for elution specifically comprises:

[0029] The DGA leaching resin mini exchange column is pre-cleaned with a mixture of 10-20 mL 0.05 mol / L HNO3 and 1.5 mol / L HF, and 10-30 mL high-purity water in sequence;

[0030] Add 3-5 mL 10-12 mol / L HNO3 to the DGA leaching resin mini exchange column for equilibrium;

[0031] The second part is diluted to 3-5 mL with 10-12 mol / L HNO3 and then loaded into the DGA leaching resin mini exchange column;

[0032] Use 3-6mL 10-12mol / LHNO3 to elute the matrix elements.

[0033] Optionally, in the above-mentioned Sr-Nd-Hf separation method, the loading of the third part onto the UTEVA leaching resin mini exchange column for elution comprises:

[0034] The UTEVA leaching resin mini exchange column is pre-cleaned with 10-20 mL 0.05 mol / L HCl and 10-30 mL high-purity water in sequence;

[0035] Add 3-5 mL 10-12 mol / L HNO3 to the UTEVA leaching resin mini exchange column for equilibrium;

[0036] The third part is diluted to 3-5 mL with 10-12 mol / L HNO3 and then loaded into the UTEVA leaching resin mini exchange column;

[0037] 3-6mL 10-12mol / LHNO3 was used to elute the matrix elements and the interfering elements Lu and Yb of Hf.

[0038] Optionally, in the above-mentioned Sr-Nd-Hf separation method, if the sample solution is a low-content sample, a set of columns formed from top to bottom by a UTEVA leaching resin mini exchange column, an SR leaching resin mini exchange column, and a DGA leaching resin mini exchange column is used for analysis, including:

[0039] Add 3-5 mL 10-12 mol / L HNO3 to the UTEVA leaching resin mini exchange column, the SR leaching resin mini exchange column, and the DGA leaching resin mini exchange column for balance;

[0040] The UTEVA leaching resin mini exchange column, the SR leaching resin mini exchange column, and the DGA leaching resin mini exchange column are sequentially combined to form a set of columns;

[0041] After the low-content sample is loaded into the column assembly, 1-2 mL 10-12 mol / L HNO3 is added 3 times to elute the matrix elements and the interfering element Rb;

[0042] After disassembling the set of columns, the SR leaching resin mini exchange column was analyzed using 0.45 mol / L HNO3 to obtain an elemental analysis solution of Sr; the DGA leaching resin mini exchange column was eluted with 2.6 mol / L HCl and analyzed with 1.8 mol / L HCl in sequence to obtain an elemental analysis solution of Nd; and the UTEVA leaching resin mini exchange column was analyzed using 4.5 mol / L HNO3 to obtain an elemental analysis solution of Hf.

[0043] Optionally, in the above-mentioned Sr-Nd-Hf separation method, the analysis using 0.45 mol / L HNO3 specifically includes:

[0044] The SR elution resin mini exchange column is eluted 3-5 times with 2-3 mL 0.45 mol / L HNO3 to analyze the target element Sr to obtain an element analysis solution containing Sr;

[0045] The steps of eluting with 2.6 mol / L HCl and analyzing with 1.8 mol / L HCl in sequence include:

[0046] Add 2-3mL 2.6mol / L HCl to elute the DGA leaching resin mini exchange column 3 times to elute the interfering elements La, Ce, and Pr, and then use 2-3mL 1.8mol / L HCl3 to elute the DGA leaching resin mini exchange column 3 times to analyze the target element Nd to obtain a receiving solution containing Nd;

[0047] Optionally, in the above-mentioned Sr-Nd-Hf separation method, the analysis using 4.5 mol / L HNO3 includes:

[0048] 1-2 mL 4.5 mol / L HNO3 was added to elute the UTEVA leaching resin mini exchange column 3-5 times to analyze the target element Hf and obtain an element analysis solution containing Hf.

[0049] In a second aspect, the present application also provides a method for isotope analysis of Sr, Nd, and Hf, and a multi-collector inductively coupled plasma mass spectrometer is used to test the isotope ratios of Sr, Nd, and Hf elemental analysis solutions, wherein the elemental analysis solutions of Sr, Nd, and Hf are elemental analysis solutions of Sr, Nd, and Hf obtained by any of the above-mentioned Sr-Nd-Hf separation methods.

[0050] At least one of the above technical solutions adopted in this application can achieve the following beneficial effects:

[0051] The present application prepares geological samples into sample solutions with high concentration of HNO3 medium, and divides them into high-content samples and low-content samples according to the content of Sr and / or Nd; for the first time, SR, DGA and UTEVA leaching resins are creatively used in combination. For high-content samples, SR leaching resin mini exchange column, DGA leaching resin mini exchange column and UTEVA leaching resin mini exchange column are used in parallel to analyze Sr, Nd and Hf; for low-content samples, a set of columns formed from top to bottom by UTEVA leaching resin mini exchange column, SR leaching resin mini exchange column and DGA leaching resin mini exchange column are used for analysis, so as to obtain elemental analysis solutions of Sr, Nd and Hf, thereby realizing the simultaneous separation of Sr, Nd and Hf in the same sample solution. The separation process of the present application is extremely simple, which greatly reduces the complexity of Sr, Nd and Hf separation and simplifies the overall process; and the mini exchange column requires a small amount of eluting acid, the process blank is low and the recovery rate of the target element is high. Therefore, the present application is particularly suitable for some precious rock samples and rock samples with low Sr, Nd and Hf, such as the analysis and research of Sr, Nd, and Hf isotopes of meteorites and ultrabasic rock samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0053] Figure 1 A schematic flow chart of a method for separating Sr-Nd-Hf according to an embodiment of the present application is shown;

[0054] Figure 2a A schematic diagram showing a method for separating Sr-Nd-Hf from a high-content sample according to an embodiment of the present application;

[0055] Figure 2b A schematic diagram showing a method for separating Sr-Nd-Hf from a low-content sample according to an embodiment of the present application;

[0056] Figure 3a The elution curves of matrix elements, interfering elements and target elements in the Sr chemical separation step of the SR leaching resin mini exchange column in the column-set combination according to one embodiment of the present application are shown;

[0057] Figure 3b The figure shows the elution curves of matrix elements, interfering elements and target elements in the Nd chemical separation step of the DGA leaching resin mini exchange column in the sleeve-column combination according to one embodiment of the present application;

[0058] Figure 3cThe figure shows the elution curves of matrix elements, interfering elements and target elements in the Hf chemical separation step of the UTEVA leaching resin mini exchange column in the column-set combination according to an embodiment of the present application.

[0059] Note: In the above figures, the main component symbols are as follows: M represents the concentration unit mol / L. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0061] Based on the development of leaching resin separation materials, Sr, Nd and Hf elements basically have their corresponding special resins for separation and purification, which are SR leaching resin, LN / DGA leaching resin and LN / DGA / UTEVA leaching resin. For Nd isotope analysis, the distribution coefficient difference of light rare earth elements on DGA leaching resin is significantly greater than that of LN leaching resin, which is more suitable for Nd separation. For the chemical separation of Hf, LN / DGA leaching resin is used, and HF must be present in the eluent to effectively resolve Zr and Hf, but UTEVA leaching resin separation does not require HF in the eluent, and Zr and Hf can also be separated. The present application found that SR, DGA and UTEVA leaching resins have good selectivity for Sr, Nd and Hf, respectively, and these three resins can achieve the extraction of their respective target elements in a high concentration of HNO3 medium, while the matrix elements and their interfering elements are eluted.

[0062] Based on this, the present application proposes a Sr-Nd-Hf separation method, which prepares a geological sample into a sample solution with a high concentration of HNO3 medium, and divides it into a high-content sample or a low-content sample according to the content of Sr and / or Nd; for the first time, SR, DGA and UTEVA leaching resins are creatively used in combination. For high-content samples, SR leaching resin mini exchange column, DGA leaching resin mini exchange column and UTEVA leaching resin mini exchange column are used in parallel to analyze Sr, Nd and Hf; for low-content samples, a set of columns formed from top to bottom by UTEVA leaching resin mini exchange column, SR leaching resin mini exchange column and DGA leaching resin mini exchange column are used for analysis, so as to obtain elemental analysis solutions of Sr, Nd and Hf, thereby realizing the simultaneous separation of Sr, Nd and Hf in the same sample solution.

[0063] Figure 1A schematic flow chart of a method for separating Sr-Nd-Hf according to an embodiment of the present application is shown. Figure 1 It can be seen that this embodiment includes:

[0064] Sample dissolution step S1: dissolve the geological sample to obtain a sample solution in a 10-12 mol / L HNO3 medium.

[0065] The present application found that SR, DGA and UTEVA extractants have good selectivity for Sr, Nd and Hf respectively, and these three resins can achieve the extraction of their respective target elements in a high concentration HNO3 medium. Therefore, the geological sample is first configured into a sample solution of a high concentration HNO3 medium.

[0066] In some embodiments, the concentration of the HNO 3 medium is 10-12 mol / L, preferably 10 mol / L.

[0067] Specifically, in some embodiments, the sample dissolution step specifically includes: a first dissolution step: adding 1-4mL 27mol / L HF and 1-4mL 15mol / L HNO3 to 50-300mg of geological samples respectively for dissolution, and keeping warm at 150-200℃ for 5-7 days for digestion; a second dissolution step: evaporating to wet salt state at 100-130℃, and then adding 0.5-2mL 27mol / L HF and 0.5-2mL 15mol / L HNO3 respectively for dissolution, and keeping warm at 150-200℃ for 24-36 hours for digestion; a third dissolution step: evaporating to wet salt state at 100-130℃, and then using 0.5-2mL 15mol / L HNO3 for digestion twice; a fourth dissolution step: adding 2-5mL saturated boric acid solution, evaporating to dryness at 100-130℃, and eliminating residual HF in the sample digestion process; a fifth dissolution step: adding 3-5mL Dissolve the sample in 10-12 mol / L HNO3 and keep warm at 100-130°C for 4-6 hours to obtain a sample solution dissolved in 10-12 mol / L HNO3.

[0068] Preferably, in some embodiments, the first dissolution step more specifically includes: adding 4 mL 27 mol / L HF and 2 mL 15 mol / L HNO3 to 200 mg of sample to dissolve, and keeping warm at 150°C for 5 days for digestion; the second dissolution step more specifically includes: evaporating to wet salt at 120°C, and then adding 1 mL 27 mol / L HF and 1 mL 15 mol / L HNO3 to dissolve, and keeping warm at 150°C for 24 hours for digestion; the third dissolution step more specifically includes: evaporating to wet salt at 120°C, and then using 1 mL 15 mol / L HNO3 to digest twice; the fourth dissolution step more specifically includes: adding 4 mL saturated boric acid solution, evaporating to dryness at 120°C, and eliminating residual HF during sample digestion; the fifth dissolution step more specifically includes: adding 4 mL 10 mol / L HNO3 to dissolve the sample, keeping warm at 120°C for 4 hours, and obtaining a sample solution dissolved in 10 mol / L HNO3.

[0069] For example, in actual operation, 4 mL 27 mol / L HF and 2 mL 15 mol / L HNO3 can be added to 200 mg ultrabasic sample (geological sample) in sequence for dissolution (no time interval is required between the addition of HF and HNO3, and the following cases where two solvents are used are the same and will not be repeated), and digested at 150°C for 5 days; then evaporated at 120°C to a wet salt state, and then 1 mL 27 mol / L HF and 1 mL 15 mol / L HNO3 were added in sequence for dissolution, and digested at 150°C for 24 hours; then evaporated at 120°C to a wet salt state, and then digested twice with 1 mL 15 mol / L HNO3; then 4 mL saturated boric acid solution (0.4 mol / L, boric acid medium is 0.75 mol / L HNO3) was added, and evaporated to dryness at 120°C to eliminate residual HF in the sample digestion process; finally, 4 mL 10M Dissolve the sample in HNO3 and keep it at 120℃ for 4 hours to obtain a sample solution dissolved in 10MHNO3.

[0070] The actual operation can be referred to as follows: weigh 200 mg of rock powder sample into a PFA melting cup, add 4 mL 27 mol / L HF and 2 mL 15 mol / L HNO3 to dissolve, place on a hot plate at 150 ° C for 5 days for digestion; after cooling, open the melting cup, evaporate at 120 ° C to a wet salt state, then add 1 mL 27 mol / L HF and 1 mL 15 mol / L HNO3 to dissolve, place on a hot plate at 150 ° C for 24 hours for digestion; after cooling, open the melting cup, evaporate at 120 ° C to a wet salt state; then, use 1 mL 15 mol / L HNO3 to digest twice; then add 4 mL saturated boric acid solution (0.4 mol / L, boric acid medium is 0.75 mol / L HNO3), evaporate to dryness at 120 ° C; finally add 4 mL The sample was dissolved in 10 mol / L HNO3 and kept at 120°C for 4 hours to obtain a sample solution dissolved in 10 mol / L HNO3 for the next step of separation and enrichment of Sr, Nd, and Hf by a resin column.

[0071] The principle of the above sample dissolution process is as follows: HF-HNO3 is used to digest ultrabasic rocks, and Ca, Mg and REE elements in the sample will form fluoride precipitation. By adding H3BO3 and using the H3BO3 complex method, volatile BF3 is formed to achieve the purpose of fluoride decomposition and HF elimination. For a 200mg sample, the final content of H3BO3 added is determined to be 4mL, so as to ensure that HF ​​in the dissolved sample is completely driven out.

[0072] Sample classification step S2: testing the content of Sr and / or Nd in the sample solution, and classifying the sample into a high-content sample or a low-content sample.

[0073] For samples with different contents, this application performs different treatments, and divides the sample solutions into high-content samples or low-content samples based on the content of Sr and / or Nd.

[0074] Specifically, inductively coupled plasma mass spectrometry (ICP-MS) testing can be used, such as taking 0.05 mL of the sample solution, adding ultrapure water to dilute the volume to 3 mL, and then performing content testing on ICP-MS.

[0075] When the Sr content or the Nd content or the sum of the Sr content and the Nd content in a sample solution is lower than a certain threshold, such as the Sr content is lower than 1 μg / g or the Nd content is lower than 0.1 μg / g or the sum of the Sr content and the Nd content is lower than 0.2 μg / g, it can be determined as a low-content sample; otherwise, it can be determined as a high-content sample.

[0076] Chemical separation step S3: If the sample solution is a high-content sample, it is divided into three parts, and analyzed using SR leaching resin mini exchange column, DGA leaching resin mini exchange column, and UTEVA leaching resin mini exchange column respectively; if the sample solution is a low-content sample, it is analyzed using a set of columns formed from top to bottom by UTEVA leaching resin mini exchange column, SR leaching resin mini exchange column, and DGA leaching resin mini exchange column to obtain elemental analysis solutions of Sr, Nd, and Hf.

[0077] For high-content samples, a "parallel" method is used for analysis. Specifically, in some embodiments, it is divided into three parts, and SR leaching resin mini exchange column, DGA leaching resin mini exchange column, and UTEVA leaching resin mini exchange column are used for analysis to obtain elemental analysis solutions of Sr, Nd, and Hf.

[0078] Normally, an appropriate amount of sample solution can be loaded onto the SR leaching resin mini exchange column and the DGA leaching resin mini exchange column respectively, and the remaining majority of the sample solution can be loaded onto the UTEVA leaching resin mini exchange column, so that the matrix elements in the sample solution and the interfering elements of its target elements can be separated.

[0079] Specifically, in some embodiments, if the sample solution is a high-content sample, it is divided into three parts, and analyzed using SR leaching resin mini exchange column, DGA leaching resin mini exchange column, and UTEVA leaching resin mini exchange column respectively, specifically including: dividing the high-content sample into a first part, a second part, and a third part; loading the first part on the SR leaching resin mini exchange column for elution, and then using 0.45 mol / L HNO3 for analysis to obtain an elemental analysis solution of Sr; loading the second part on the DGA leaching resin mini exchange column for elution, and then using 2.6 mol / L HCl for elution and 1.8 mol / L HCl for analysis in turn to obtain an elemental analysis solution of Nd; loading the third part on the UTEVA leaching resin mini exchange column for elution, and then using 4.5 mol / L HNO3 for analysis to obtain an elemental analysis solution of Hf.

[0080] In actual operation, a small amount of sample solution dissolved in 10 mol / L HNO3 can be first loaded onto the SR leaching resin mini exchange column and the DGA leaching resin mini exchange column respectively, and the remaining majority of the sample solution can be loaded onto the UTEVA leaching resin mini exchange column to remove the Ca, Mg, Fe, Al, Na, K, Ba matrix elements, the interfering element Rb of Sr and the interfering elements Lu and Yb of Hf in the sample solution.

[0081] It should be noted that the present application does not limit the relative amounts of the first part, the second part and the third part, which can be determined according to actual needs such as the source of the sample and the test.

[0082] After elution, the SR leaching resin mini exchange column was analyzed using 0.45 mol / L HNO3 to obtain the elemental analysis solution of Sr; the DGA leaching resin mini exchange column was successively analyzed using 2.6 mol / L HCl to elute the interfering elements La, Ce, Pr and 1.8 mol / L HCl to obtain the elemental analysis solution of Nd; the UTEVA leaching resin mini exchange column was analyzed using 4.5 mol / L HNO3 to obtain the elemental analysis solution of Hf.

[0083] (1) SR leaching resin exchange column separation and enrichment of Sr:

[0084] In some embodiments, the SR leaching resin mini exchange column is made by loading 1±0.1mL 50-100μm SR into a Poly-Prep chromatography empty column with an inner diameter of 5mm and a porous polyethylene gasket at the lower end; the UTEVA leaching resin mini exchange column is made by loading 1±0.1mL 50-100μm UTEVA into a Poly-Prep chromatography empty column with an inner diameter of 5mm and a porous polyethylene gasket at the lower end; the DGA leaching resin mini exchange column is made by mixing 0.5±0.1mL 50-100μm and 0.5±0.1mL 100-200μm DGA leaching resins evenly and then loading them into a Poly-Prep chromatography empty column with an inner diameter of 5mm and a porous polyethylene gasket at the lower end.

[0085] Preferably, the SR leaching resin mini exchange column is made by filling 1 mL of 50-100 μm SR in a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end; the UTEVA leaching resin mini exchange column is made by filling 1 mL of 50-100 μm UTEVA in a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end; the DGA leaching resin mini exchange column is made by mixing 0.5 mL of 50-100 μm and 0.5 mL of 100-200 μm DGA leaching resins evenly and then filling them in a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end.

[0086] In some embodiments of the present application, the loading of the first part onto the SR leaching resin mini exchange column for elution specifically comprises: pre-cleaning the SR leaching resin mini exchange column with 10-20 mL 0.05 mol / L HCl and 10-30 mL high-purity water in sequence; adding 3-5 mL 10-12 mol / L HNO3 to the SR leaching resin mini exchange column for balance; adjusting the volume of the first part to 3-5 mL with 10-12 mol / L HNO3 and then loading it into the SR leaching resin mini exchange column; and eluting the matrix elements and the interfering element Rb of Sr with 3-6 mL 10-12 mol / L HNO3.

[0087] Preferably, the step of loading the first part onto the SR leaching resin mini exchange column for elution more specifically comprises: pre-cleaning the SR leaching resin mini exchange column with 10 mL 0.05 mol / L HCl and 20 mL high-purity water in sequence; adding 3 mL 10 mol / L HNO3 to the SR leaching resin mini exchange column for balance; adjusting the volume of the first part to 4 mL with 10 M HNO3 and then loading it into the SR leaching resin mini exchange column; and eluting the matrix elements and the interfering element Rb of Sr with 3 mL 10 mol / L HNO3.

[0088] For example, the SR leaching resin mini exchange column was pre-cleaned with 10mL 0.05mol / L HCl and 20mL high-purity water in sequence; 3mL 10mol / L HNO3 was added for balance, an appropriate amount of sample solution was taken to make the volume to 4mL10mol / LHNO3, loaded into the SR leaching resin mini exchange column, and then 3mL10mol / LHNO3 was added to elute the matrix elements and Sr interfering elements Rb.

[0089] Then, 0.45mol / L HNO3 is used for analysis. In some embodiments, it specifically includes: 2-3mL0.45mol / L HNO3 is used to elute the SR leaching resin mini exchange column 3-5 times, the target element Sr is analyzed, and an element analysis solution containing Sr is obtained. Preferably, the 0.45mol / L HNO3 is used for analysis, more specifically includes: 2mL 0.45mol / LHNO3 is used to elute the SR leaching resin mini exchange column 4 times, the target element Sr is analyzed, and an element analysis solution containing Sr is obtained.

[0090] For example, 2 mL of 0.45 M HNO3 was added 4 times to elute the SR eluting resin mini exchange column, and the target element Sr was analyzed to obtain a receiving solution containing Sr, that is, an elemental analysis solution of Sr.

[0091] In order to more intuitively illustrate the elution and analysis process of the SR elution resin mini exchange column, the above dosage is taken as an example and the process is summarized in Table 1:

[0092] Table 1: SR resin column matrix elements, interfering elements and Sr separation and enrichment process

[0093]

[0094] The principle of the SR leaching resin mini exchange column chemical separation process is as follows: First, refer to the attached Figure 3a On the SR resin column, under the medium of 10mol / L HNO3, matrix elements such as Ca, Mg, Fe, Al, K, Na, Ba, Rb and REE are weakly retained, while Sr is extremely strongly retained. Therefore, after loading the sample solution and eluting the resin column with 1mL 10mol / L HNO3 for 3 times, more than 98.6% of matrix elements such as Ca, Mg, Fe, Al, K, Na, Ba, Rb and REE are eluted, and Sr is not eluted; because under the medium of 0.45mol / L HNO3 on the SR resin column, the retention of Sr is very weak, so by eluting the resin column with 2mL0.45mol / L HNO3 for 4 times, more than 98% of Sr can be eluted.

[0095] (2) DGA leaching resin exchange column separation and enrichment of Nd:

[0096] In some embodiments of the present application, the loading of the second part onto the DGA leaching resin mini exchange column for elution specifically comprises: pre-cleaning the DGA leaching resin mini exchange column with a mixture of 10-20 mL 0.05 mol / L HNO3 and 1.5 mol / L HF, and 10-30 mL high-purity water in sequence; adding 3-5 mL 10-12 mol / L HNO3 to the DGA leaching resin mini exchange column for balance; adjusting the volume of the second part to 3-5 mL with 10-12 mol / L HNO3 and then loading it into the DGA leaching resin mini exchange column; and eluting the matrix elements with 3-6 mL 10-12 mol / L HNO3.

[0097] Preferably, the step of loading the second part onto the DGA leaching resin mini exchange column for elution more specifically comprises: pre-cleaning the DGA leaching resin mini exchange column with a mixture of 10 mL of 0.05 mol / L HNO3 and 1.5 mol / L HF, and 20 mL of high-purity water in sequence; adding 3 mL of 10 mol / L HNO3 to the DGA leaching resin mini exchange column for balance; loading the second part into the DGA leaching resin mini exchange column after adjusting the volume to 4 mL with 10 mol / L HNO3; and eluting the matrix elements with 3 mL of 10 mol / L HNO3.

[0098] For example, for the DGA leaching resin mini exchange column, use 10mL 0.05mol / LHNO3-1.5mol / LHF and 20mL high-purity water for pre-cleaning, add 3mL 10mol / L HNO3 for balance, take an appropriate amount of sample solution to make the volume to 4mL10mol / LHNO3, load it into the DGA leaching resin mini exchange column, and then add 3mL 10mol / L HNO3 to elute the matrix elements.

[0099] Then, 2.6mol / L HCl was used for elution and 1.8mol / L HCl was used for analysis. In some embodiments, 2.6mol / L HCl was used for elution and 1.8mol / L HCl was used for analysis, specifically including: adding 2-3mL 2.6mol / LHCl to elute the DGA elution resin mini exchange column 3 times to elute the interfering elements La, Ce, and Pr, and then using 2-3mL1.8mol / L HCl to elute the DGA elution resin mini exchange column 3 times to analyze the target element Nd to obtain a receiving solution containing Nd.

[0100] Preferably, the elution with 2.6mol / L HCl and the analysis with 1.8mol / L HCl are used in sequence, and more specifically, 2mL 2.6mol / L HCl is added to elute the DGA leaching resin mini exchange column 3 times to elute the interfering elements La, Ce, and Pr, and then 2mL 1.8mol / L HCl3 is used to elute the DGA leaching resin mini exchange column 3 times to analyze the target element Nd to obtain a receiving solution containing Nd.

[0101] For example, 2 mL 2.6 mol / L HCl is added three times to elute the exchange column of the DGA leaching resin to elute the interfering elements La, Ce, and Pr, and then 2 mL 1.8 mol / L HCl is used to elute the exchange column of the DGA leaching resin three times to analyze the target element Nd to obtain a receiving solution containing Nd, that is, an element receiving solution of Nd.

[0102] In order to more intuitively illustrate the elution and analysis process of the DGA leaching resin mini exchange column, the above dosage is taken as an example and the process is summarized in Table 2.

[0103] Table 2: DGA resin column matrix elements, interfering elements and Nd separation and enrichment process

[0104]

[0105]

[0106] The principle of the DGA leaching resin mini exchange column chemical separation process is as follows: First, refer to the attached Figure 3b On the DGA resin column, under the condition of 10mol / L HNO3 medium, matrix elements such as Ca, Mg, Fe, Al, K, Na, Ba are weakly retained, while REE is extremely strongly retained. Therefore, after loading the sample solution and eluting the resin column with 1mL10mol / L HNO3 for 3 times, more than 98% of the matrix elements such as Ca, Mg, Fe, Al, K, Na, Ba are eluted, while REE is not eluted; because on the DGA resin column, under the medium of HCl, there are large differences in the distribution coefficients between light rare earth elements, under the medium of 2.6mol / L HCl, La, Ce, Pr are weakly retained, while Nd is strongly retained, so by eluting the resin column with 2mL 2.6mol / L HCl for 3 times, >97.8% of La, Ce, Pr can be eluted, while Nd is not eluted. Under the medium condition of 1.8 mol / L HCl, Nd has a lower distribution coefficient and is weakly retained by the DGA resin column. By eluting the resin column with 2 mL 1.8 M HCl three times, more than 98.4% of Nd can be resolved, and the interfering element Sm is not eluted.

[0107] (3) UTEVA leaching resin exchange column separates and enriches Hf:

[0108] In some embodiments of the present application, the loading of the third part onto the UTEVA leaching resin mini exchange column for elution comprises: pre-cleaning the UTEVA leaching resin mini exchange column with 10-20 mL 0.05 mol / L HCl and 10-30 mL high-purity water in sequence; adding 3-5 mL 10-12 mol / L HNO3 to the UTEVA leaching resin mini exchange column for equilibration; adjusting the volume of the third part to 3-5 mL with 10-12 mol / L HNO3 and then loading it into the UTEVA leaching resin mini exchange column; and eluting the matrix elements and the interfering elements Lu and Yb of Hf with 3-6 mL 10-12 mol / L HNO3.

[0109] Preferably, the loading of the third part onto the UTEVA leaching resin mini exchange column for elution more specifically comprises: pre-cleaning the UTEVA leaching resin mini exchange column with 10 mL 0.05 mol / L HCl and 20 mL high-purity water; adding 3 mL 10 mol / L HNO3 to the UTEVA leaching resin mini exchange column for balance; adjusting the volume of the third part to 4 mL with 10 mol / L HNO3 and then loading it into the UTEVA leaching resin mini exchange column; and eluting the matrix elements and the interfering elements Lu and Yb of Hf with 3 mL 10 mol / L HNO3.

[0110] For example, for the UTEVA leaching resin mini exchange column, use 10mL 0.05mol / L HCl and 20mL high-purity water for pre-cleaning; add 3mL 10mol / L HNO3 for balance, take an appropriate amount of sample solution to make the volume to 4mL10mol / LHNO3, load it into the SR leaching resin mini exchange column, and then add 3mL10mol / LHNO3 to elute the matrix elements and Hf interfering elements Lu and Yb.

[0111] Then, the analysis is performed using 4.5mol / L HNO3, which in some embodiments includes: adding 1-2mL 4.5mol / L HNO3 to elute the UTEVA leaching resin mini exchange column 3-5 times, analyzing the target element Hf, and obtaining an element analysis solution containing Hf. Preferably, more specifically, it includes: adding 1mL 4.5mol / L HNO3 to elute the UTEVA leaching resin mini exchange column 4 times, analyzing the target element Hf, and obtaining an element analysis solution containing Hf.

[0112] For example, 1 mL of 4.5 mol / L HNO3 was added 4 times to elute the UTEVA elutable resin mini exchange column, and the target element Hf was analyzed to obtain a receiving solution containing Hf, that is, an elemental analysis solution of Hf.

[0113] In order to more intuitively illustrate the elution and analysis process of the UTEVA leaching resin mini exchange column, the above dosage is taken as an example and the process is summarized in Table 3.

[0114] Table 3: UTEVA resin column matrix elements, interfering elements and Hf separation and enrichment process

[0115]

[0116] The principle of the chemical separation process of UTEVA leaching resin mini exchange column is as follows: First, refer to the attached Figure 3cOn the UTEVA resin column, under the medium of 10mol / L HNO3, matrix elements such as Ca, Mg, Fe, Al, K, Na, Ba, Rb and REE are weakly retained, while Hf and Zr are extremely strongly retained. Therefore, after the sample solution is loaded and the resin column is eluted with 1mL 10mol / L HNO3 for 3 times, more than 98% of the matrix elements such as Ca, Mg, Fe, Al, K, Na, Ba, Rb and REE are eluted, while Hf and Zr are not eluted; due to the difference in the distribution coefficients of Hf and Zr in the nitric acid medium on the UTEVA resin column, the separation of Hf and Zr can be achieved. Under the medium of 4.5mol / L HNO3, Hf is weakly retained and Zr is strongly retained. Therefore, by eluting the resin column with 1mL 4.5mol / L HNO3 for 4 times, >99.2% of Hf can be eluted, while Zr is not eluted.

[0117] For low-content samples, a "column combination" is used for analysis. From top to bottom, a column combination consisting of UTEVA leaching resin mini exchange column, SR leaching resin mini exchange column, and DGA leaching resin mini exchange column is used for analysis to obtain elemental analysis solutions of Sr, Nd, and Hf.

[0118] Specifically, in some embodiments, if the sample solution is a high-content sample, a set of columns formed from top to bottom by a UTEVA leaching resin mini exchange column, an SR leaching resin mini exchange column, and a DGA leaching resin mini exchange column is used for analysis, including: adding 3-5mL 10-12mol / L HNO3 to the UTEVA leaching resin mini exchange column, the SR leaching resin mini exchange column, and the DGA leaching resin mini exchange column for balance; combining the UTEVA leaching resin mini exchange column, the SR leaching resin mini exchange column, and the DGA leaching resin mini exchange column in order to form a set of columns; after loading the low-content sample into the set of columns, adding 1-2mL 10-12mol / LHNO3 three times to elute the matrix elements and the interfering element Rb; after disassembling the set of columns, the SR leaching resin mini exchange column is treated with 0.45mol / L HNO3 was used for analysis to obtain an elemental analysis solution of Sr; the DGA leaching resin mini exchange column was eluted with 2.6 mol / L HCl and analyzed with 1.8 mol / L HCl in sequence to obtain an elemental analysis solution of Nd; and the UTEVA leaching resin mini exchange column was analyzed with 4.5 mol / L HNO3 to obtain an elemental analysis solution of Hf.

[0119] The column-column method is mainly used for low-content samples. In order to ensure that a sufficient content of the target elements is obtained, a combination of SR-DGA-UTEVA resin exchange column column-column method is used for chemical separation. For example, the SR, DG and UTEVA resin exchange columns are balanced with 3mL 10mol / L HNO3 respectively, and then the columns are combined from top to bottom in the order of UTEVA leaching resin mini exchange column, SR leaching resin mini exchange column and DGA leaching resin mini exchange column. The sample solution was loaded onto the assembled set of columns, and then 1 mL 10 mol / L HNO3 was added three times to elute the matrix elements such as Ca, Mg, Fe, Al, K, Na, Ba and the interfering element Rb. Hf was adsorbed by the top UTEVA resin, Sr was adsorbed by the middle SR resin column, and Nd and other rare earth elements were adsorbed by the bottom DGA resin; then the mini exchange columns of these three resins were separated, and according to the aforementioned method, the SR leaching resin mini exchange column was analyzed with 0.45 mol / L HNO3 to obtain the elemental analysis solution of Sr; the DGA leaching resin mini exchange column was successively eluted with 2.6 mol / L HCl and analyzed with 1.8 mol / L HCl to obtain the elemental analysis solution of Nd; the UTEVA leaching resin mini exchange column was analyzed with 4.5 mol / L HNO3 to obtain the elemental analysis solution of Hf. The specific analysis method is the same as above and will not be repeated.

[0120] It can be seen from the above examples that: under the medium of high concentration HNO3, Sr is strongly retained on SR resin, Nd is strongly retained on DGA resin and Hf is strongly retained on UTEVA resin, while matrix elements and their interfering elements are weakly retained on their corresponding resins, and the separation of matrix elements and interfering elements can be achieved during the sample loading process. On DGA resin, Nd and its interfering elements La, Ce, and Pr have a large distribution coefficient difference. The DGA resin is eluted with 2.6mol / L HCl and 1.8mol / L HCl in turn, which can well separate Nd and its interfering elements La, Ce, and Pr. UTEVA resin is used for Hf separation, and HF is not required in the eluent, and when Hf is analyzed using HNO3, Hf can be separated from Zr. In addition, the matrix elements are not adsorbed by these three resin columns under the separation conditions, so that these resins have a large sample carrying capacity, so a mini exchange column filled with a small amount of leaching resin can meet the sample carrying capacity requirements for the separation of Sr, Nd and Hf in most geological samples. Based on the abundance of Sr, Nd and Hf in nature, a small amount of rock samples can meet the analysis requirements of Sr and Nd isotopes, most of the remaining samples can be used for Hf analysis, and these three resin exchange columns can be chemically separated at the same time, greatly improving the analysis efficiency. Moreover, for samples with low Sr, Nd and Hf content, these three resin exchange columns can be combined, and low-content sample Sr, Nd and Hf isotope analysis can be performed later. It can be seen that the present application can simultaneously separate Sr, Nd and Hf from the same sample solution. The overall process is extremely simple, the mini exchange column requires a small amount of eluting acid, the process blank is low and the target element recovery rate is high; it is particularly suitable for some precious rock samples and rock samples with low Sr, Nd and Hf, such as meteorites and ultrabasic rocks Sr, Nd, Hf isotope analysis.

[0121] After obtaining the elemental analysis solutions of Sr, Nd, and Hf, the isotope analysis of Sr, Nd, and Hf can be performed. The multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) can be used to test the isotope ratio of Sr, Nd, and Hf obtained by any of the above methods. It should be noted that the elemental analysis solutions of Sr and Nd can be directly used for MC-ICP-MS testing; the elemental analysis solution of Hf is best heated and evaporated, and HNO3 is added to dissolve it, such as adding 0.3 mol / L HNO3 and heating at 120°C to dissolve it, to obtain a solution containing the target element Hf, which can be used for MC-ICP-MS testing.

[0122] In the above embodiment, the instrument model of the MC-ICP-MS can be selected from but not limited to: Nu PlasmaⅡ; preferably, Sr isotope mass spectrometry test adopts direct solution injection, and Nd and Hf isotope mass spectrometry test adopts ApexΩ membrane desolvation injection system injection.

[0123] Embodiment 1:

[0124] Sr, Nd, Hf isotope analysis of basalt international rock standard BCR-2

[0125] (1) Dissolving the sample: Weigh 50 mg of BCR-2 basalt standard powder and place it in a PFA dissolving cup. Add 2 mL of purified concentrated nitric acid and 4 mL of concentrated hydrofluoric acid (first add 0.5 mL of concentrated nitric acid dropwise, and then add 1.5 mL of concentrated nitric acid and 4 mL of concentrated hydrofluoric acid after the sample no longer produces bubbles). Place the sample on a hot plate at 150°C for 5 days. After cooling, open the dissolving cup and evaporate it on a hot plate at 120°C until it is wet salt. Then add 1 mL of concentrated nitric acid and 1 mL of concentrated hydrofluoric acid to dissolve it. Place the sample on a hot plate at 150°C for 24 hours for digestion. Then, use 1 mL of concentrated nitric acid to dissolve the sample, evaporate it to dryness, and repeat once. Then add 4 mL of saturated boric acid solution (0.4 mol / L, the boric acid medium is 0.75 mol / L HNO3) and evaporate it at 120°C until it is completely dry. Finally, add 4 mL The sample was dissolved in 10 mol / L HNO3 and kept at 120°C for 24 hours to obtain a sample solution dissolved in 10 mol / L HNO3, which was extracted into a centrifuge tube. The extracted sample was centrifuged (4000 rpm, 5 min) and then cleared for column loading.

[0126] (2) Chemical separation and enrichment: For the chemical separation and enrichment process, see Figure 2a And Tables 1 to 3.

[0127] The Bio-rad Poly-Prep chromatography column has an inner diameter of 5mm, with a porous polyethylene gasket at the bottom, loaded with 1mL of French SR resin (TrisKem International) with a resin particle size of 50-100μm, to obtain an SR leaching resin mini exchange column. The SR leaching resin mini exchange column was pre-cleaned with 10mL 0.05mol / L HCl and 20mL high-purity water, and the SR leaching resin mini exchange column was balanced with 3mL 10mol / L HNO3. Subsequently, a small amount of sample solution was added to 10mol / L HNO3 solution to a constant volume of 4mL on the column; then 1mL 10mol / L HNO3 was added 3 times to elute matrix elements such as Ca, Mg, Fe, Al, K, Na, Ba and interfering elements Rb, and Sr was still adsorbed by the SR resin column. Subsequently, 2mL0.45mol / L HNO3 was added 4 times to elute Sr, and the recovery rate of Sr was >98%. The separated Sr-containing receiving solution can be directly subjected to MC-ICP-MS high-precision Sr isotope analysis.

[0128] 0.5mL of French DGA leaching resin (TrisKem International) with a resin particle size of 50-100μm and 0.5mL of resin particle size of 100-200μm were mixed evenly and loaded into a Bio-radPoly-Prep chromatography column with an inner diameter of 5mm and a porous polyethylene gasket at the lower end to obtain a DGA leaching resin mini exchange column. The DGA leaching resin mini exchange column was pre-cleaned with 10mL 0.05mol / LHNO3-1.5mol / L HF and 20mL high-purity water, and the DGA leaching resin mini exchange column was balanced with 3mL 10mol / L HNO3. Subsequently, a small amount of sample solution was added with 10mol / L HNO3 solution to a constant volume of 4mL on the column; then 1mL10mol / L HNO3 was added 3 times to elute Ca, Mg, Fe, Al, K, Na, Ba and other matrix elements, while REE was strongly retained by the DGA resin column. Subsequently, 2 mL of 2.6 mol / L HCl was added three times to elute the interfering elements La, Ce, and Pr, and 2 mL of 1.8 mol / L HCl was added three times to analyze Nd. The recovery rate of Nd was >98.5%, and the obtained Nd receiving solution could be directly used for MC-ICP-MS for high-precision Nd isotope analysis.

[0129] The Bio-rad Poly-Prep chromatography column has an inner diameter of 5mm, with a porous polyethylene gasket at the bottom, loaded with 1mL of French UTEVA resin (TrisKem International) with a resin particle size of 50-100μm, to obtain a UTEVA leaching resin mini exchange column. The UTEVA leaching resin mini exchange column was pre-cleaned with 10mL 0.05mol / L HCl and 20mL high-purity water, and the UTEVA leaching resin mini exchange column was balanced with 3mL 10mol / L HNO3. Subsequently, the remaining sample solution was fixed to 4mL on the column with 10mol / L HNO3 solution; 1mL 10mol / L HNO3 was added 3 times to elute Ca, Mg, Fe, Al, K, Na, Ba and other matrix elements and REE, while Zr and Hf were strongly retained by the UTEVA leaching resin mini exchange column. Subsequently, 1mL 4.5mol / L HNO3 was added 4 times to resolve Hf, Zr was not eluted, and the recovery rate of Hf was >99%. The separated Hf receiving solution was evaporated to a small volume at 100°C, and then 0.3 mol / L HNO3 was added to make up the volume for high-precision Hf isotope analysis by MC-ICP-MS.

[0130] (3) Determination of Sr, Nd, and Hf isotopes by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS):

[0131] The instrument used is the Nu Plasma Ⅱ multi-collector inductively coupled plasma mass spectrometer produced by Nu Instruments in the UK, which is equipped with 16 Faraday cups and 5 ion counters. The specific test process is as follows:

[0132] Sr isotope ratio test: Faraday cups H5, H3, H1, L1, L3 and L5 are used to receive 88 Sr. 87 Sr. 86 Sr. 85 Rb, 84 Sr and 83 Kr. 84 K + and 86 K + right 84 Sr + and 86 Sr + interference, by monitoring 83 K + , and based on 84 Kr=0.2017× 83 Kr and 86 Kr=0.6647× 83 Kr is corrected. 87 R + right 87 Sr + The interference is monitored by 85 R + and through 87 Rb=0.38572× 85 Rb is corrected (as in reference 1). According to the exponential law, 86 Sr / 88 Sr=0.1194 pairs 87 Sr / 86 The Sr calibration was performed (as in references 2, 3). The sample analysis was performed by solution injection, and the instrument parameters were optimized using a standard solution NBS987 with a concentration of 300 ng / mL Sr.

[0133] Nd isotope ratio test: using Faraday cups H5, H4, H3, H2, H1, L1, L2 and L4 to receive 149 Sm, 148 Nd, 147 Sm, 146 Nd, 145 Nd, 143 Nd, 142 Nd and 140 Ce. Center cup (Ax) receiving 144 Nd. 142Ce + right 142 Nd + interference, by monitoring 140 Nd + , and based on 142 Ce=0.125653× 140 Ce is corrected. 144 Sm + and 148 Sm + Respectively 144 Nd + and 148 Nd + interference, by monitoring 147 Sm + , and respectively based on 144 Sm=0.204803× 147 Sm and 148 Sm=0.749833× 147 Sm is corrected. According to the exponential law, 146 Nd / 144 Nd=0.7219 pairs 143 Nd / 144 Nd was calibrated (as in references 2, 3). Sample analysis was performed using a membrane desolvation and injection system (ApexΩ, Elemental Scientific, Omaha, NE, USA), and instrument parameters were optimized using a standard solution of 30 ng / mL Nd, JNdi-1.

[0134] Hf isotope ratio test: using Faraday cups H5, H4, H3, H2, H1, L1, L2, L3 and L4 to receive 180 Hf 179 Hf 178 Hf 177 Hf 176 Hf 174 Hf 173 Yb, 172 Yb and 171 Yb. Center cup (Ax) receiving 175 Lu. 176 Yb + and 176 Lu + right 176 Hf + interference, by monitoring 175 Lu + and 173 Yb + , and based on 176 Lu=0.0265× 175 Lu and176 Yb=0.79323× 173 Yb is corrected. According to the exponential law, 179 Hf / 177 Hf=0.7325 pairs 176 Hf / 177 Hf was calibrated (as in references 2, 3). Sample analysis was performed using a membrane desolvation and injection system (ApexΩ, Elemental Scientific, Omaha, NE, USA), and instrument parameters were optimized using a standard solution of Alfa Hf with a concentration of 30 ng / mL Hf.

[0135] The data acquisition of Sr, Nd and Hf of the samples was set up with 2 blocks, each block had 20 cycles, and the integration time of each cycle was 15 seconds. Between sample analyses, the injection system was cleaned with 0.3mol / L HNO3 and 0.75mol / L HNO3. Under the optimized instrument conditions, the repeated test results of standard solutions NBS 987Sr, JNdi-1 Nd and Alfa Hf were: 0.710250±0.000012(2s, n=10), 0.512116±0.000006(2s, n=10) and 0.282186±0.000016(2s, n=10), respectively. The instrument parameters of the multi-collector inductively coupled plasma mass spectrometer for the specific Sr, Nd and Hf isotope ratio tests are shown in Table 4.

[0136] Table 4: MC-ICP-MS test parameters for Sr-Nd-Hf isotope ratios of rock standard sample BCR-2

[0137]

[0138] Accuracy of the determination results of Sr, Nd, Hf isotope ratios of BCR-2 basalt:

[0139] The results of the determination of the isotope ratios of Sr, Nd, and Hf in basalt BCR-2 are listed in Table 5. 87 Sr / 86 Sr. 143 Nd / 144 Nd and 176 Hf / 177 The Hf measurement results were 0.705010±0.000018, 0.512632±0.000008 and 0.282885±0.000019, respectively, which were consistent with the results reported in literature 2, 3, 4 and 5 within the error range.

[0140] Table 5: Rock Standard Sample BCR-2 87 Sr / 86 Sr.143 Nd / 144 Nd and 176 Hf / 177 Hf isotope ratio determination results

[0141]

[0142] Embodiment 2:

[0143] Andesite International Rock Standard AGV-2Sr, Nd, Hf Isotope Analysis

[0144] The chemical process of Example 2 is basically the same as that of Example 1, except that the geological sample used in this example is the international standard sample AGV-2 of andesite, and the test results of Sr, Nd, and Hf isotope ratios are shown in Table 6.

[0145] The accuracy of the Sr, Nd, Hf isotope ratio determination results of AGV-2 andesite:

[0146] The results of the determination of the isotope ratios of Sr, Nd, and Hf in andesite AGV-2 are listed in Table 6. 87 Sr / 86 Sr. 143 Nd / 144 Nd and 176 Hf / 177 The Hf measurement results were 0.703988±0.000015, 0.512789±0.000011 and 0.282972±0.000027, respectively, which were consistent with the results reported in literature 2, 3, 4, and 5 within the error range.

[0147] Table 6: Rock standard sample AGV-2 87 Sr / 86 Sr. 143 Nd / 144 Nd and 176 Hf / 177 Hf isotope ratio determination results

[0148]

[0149] Embodiment 3:

[0150] Analysis of Sr, Nd and Hf isotopes of UB-N, an international rock standard for peridotite

[0151] The geological sample selected in Example 3 is the international standard sample of peridotite UB-N, which has low Nd and Hf contents. To ensure that sufficient contents of target elements are obtained, a combination of SR-DGA-UTEVA resin exchange column and column is used for chemical separation, such as Figure 2bAs shown. The UTEVA, DG and SR leaching resin mini-exchange columns were balanced with 3mL 10mol / L HNO3, and then the columns were assembled from top to bottom. The UB-N rock solution dissolved in 4mL 10mol / L HNO3 was loaded on the assembled column assembly, and then 1mL 10mol / L HNO3 was added 3 times to elute the matrix elements such as Ca, Mg, Fe, Al, K, Na, Ba and the interfering element Rb. Hf was adsorbed by the top UTEVA leaching resin mini-exchange column, Sr was adsorbed by the middle SR leaching resin mini-exchange column, and Nd and other rare earth elements were adsorbed by the bottom DGA leaching resin mini-exchange column; then the three leaching resin mini-exchange columns were separated, and the SR, DG and UTEVA leaching resin mini-exchange columns were chemically separated from Sr, Nd and Hf according to the elution method in Example 1. The obtained Sr, Nd and Hf receiving solutions were treated by a method similar to that in Example 1, and then used for MC-ICP-MS to perform Sr, Nd and Hf isotope ratio testing. The test results are shown in Table 7.

[0152] Accuracy of Sr, Nd, Hf isotope ratio determination results of UB-N peridotite:

[0153] The results of determination of Sr, Nd, and Hf isotope ratios of peridotite UB-N are listed in Table 7. 87 Sr / 86 Sr. 143 Nd / 144 Nd and 176 Hf / 177 The Hf determination results were 0.709967±0.000020, 0.512929±0.000020 and 0.283261±0.000010, respectively, which were consistent with the results reported in literature 6, 7, 8 and 9 within the error range.

[0154] Table 7: Rock standard sample UB-N 87 Sr / 86 Sr. 143 Nd / 144 Nd and 176 Hf / 177 Hf isotope ratio determination results

[0155]

[0156] The following points are explained for the above embodiments 1 to 3:

[0157] First, sample dissolution and chemical separation experiments are all carried out in a Class 100 fume hood and a Class 100 clean bench in a Class 1000 clean room;

[0158] Second, GR grade hydrochloric acid, nitric acid, and hydrofluoric acid: produced by China National Pharmaceutical Group Chemical Reagent Co., Ltd., all of which are Savillex TM Acid purifier (produced by Minnetonka Company, USA, which does not reach distillation purification at boiling point) for sub-boiling distillation purification.

[0159] Third, boric acid: concentration is 0.4 mol / L, medium is 0.75 mol / L HNO3.

[0160] Fourth, ultrapure water: prepared by the American Thermo GenPure_UV_xCAD_Plus system, the water resistivity is 18.2MΩ / cm (25℃).

[0161] Fifth, the vessel for receiving the sample solution during the dissolution and chemical separation process is a Savillex TM The Teflon PFA vessels produced by the company are mainly PFA Teflon sample dissolvers with screw caps. Before use, they are cleaned with high-grade pure nitric acid, high-grade pure hydrochloric acid and ultrapure water at 120°C reflux.

[0162] Sixth, UTEVA leaching resin: produced by TrisKem International, France, with a resin particle size of 50-100μm; DGA leaching resin: produced by TrisKem International, France, with a resin particle size of 50-100μm and 100-200μm; SR leaching resin: produced by TrisKem International, France, with a resin particle size of 50-100μm.

[0163] Seventh, exchange column: polyethylene column (Poly-Prep columns, Bio-Rad Laboratories Inc., USA), with an inner diameter of 5 mm, a porous polyethylene gasket at the lower end, and filled with about 1 mL of elution resin.

[0164] Eighth, multiple collector inductively coupled plasma-mass spectrometry (MC-ICP-MS): produced by Nu Instruments, UK, model Nu PlasmaⅡ;

[0165] Ninth, membrane desolvation and sampling system: manufactured by Omaha Corporation of the United States, model is ApexΩ;

[0166] Tenth, rock standard samples: BCR-2 (basalt), AGV-2 (andesite), UB-N (peridotite, Association Nationale de la Recherche Technique) of the United States Geological Survey (USGS).

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[0175] Literature[8]:AJMcCoy-West,MAMillet and KWBurton.EarthPlanet.Sci.Lett.,2017,121-132.

[0176] Literature [9]: YV Urban Kochergina, V. Erban and JMHora. Journal Geosci., 2022, 273-285.

[0177] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for separating Sr-Nd-Hf, characterized in that: The Sr-Nd-Hf separation method comprises: Sample dissolution step: dissolve the geological sample to obtain a sample solution in 10-12 mol / L HNO3 medium; Sample classification step: testing the content of Sr and / or Nd in the sample solution, and classifying the sample solution into a high-content sample or a low-content sample; Chemical separation step: if the sample solution is a high-content sample, it is divided into three parts, and analyzed by using SR leaching resin mini exchange column, DGA leaching resin mini exchange column, and UTEVA leaching resin mini exchange column respectively; if the sample solution is a low-content sample, it is analyzed by using a set of columns formed from top to bottom by UTEVA leaching resin mini exchange column, SR leaching resin mini exchange column, and DGA leaching resin mini exchange column to obtain elemental analysis solutions of Sr, Nd, and Hf; The sample dissolution step specifically includes: First dissolution step: add 1-4mL 27mol / L HF and 1-4mL 15mol / L HNO3 to 50-300 mg of geological sample in sequence for dissolution, and keep at 150-200℃ for 5-7 days for digestion; Second dissolution step: evaporate to wet salt state at 100-130°C, then add 0.5-2mL 27mol / L HF and 0.5-2mL 15mol / L HNO3 in sequence to dissolve, and keep warm at 150-200°C for 24-36 hours to digest; The third dissolution step: evaporate to wet salt at 100-130°C, and then digest twice with 0.5-2mL 15mol / L HNO3; Fourth dissolution step: add 2-5 mL of saturated boric acid solution and evaporate to dryness at 100-130°C to eliminate residual HF during sample digestion; Fifth dissolution step: add 3-5mL 10-12mol / L HNO3 to dissolve the sample, keep warm at 100-130˚C for 4-6 hours to obtain a sample solution dissolved in 10-12mol / L HNO3; The sample classification step specifically includes: Take 0.05 mL of the sample solution, dilute it to 3 mL with ultrapure water, and then use an inductively coupled plasma mass spectrometer to test the Sr and / or Nd content; If the Sr content is lower than 1 μg / g, or the Nd content is lower than 0.1 μg / g, or the sum of the Sr content and the Nd content is lower than 0.2 μg / g, the sample solution is determined to be a low-content sample; otherwise, the sample solution is determined to be a high-content sample.

2. The Sr-Nd-Hf separation method according to claim 1, characterized in that: The first dissolution step specifically includes: adding 4 mL 27 mol / L HF and 2 mL 15 mol / L HNO3 to 200 mg of the sample in sequence for dissolution, and keeping the temperature at 150° C. for 5 days for digestion; The second dissolving step specifically includes: evaporating at 120°C to a wet salt state, then adding 1mL 27mol / L HF and 1mL 15mol / L HNO3 in sequence to dissolve, and keeping warm at 150°C for 24 hours to digest; The third dissolution step specifically includes: evaporating at 120°C to a wet salt state, and then digesting twice with 1mL 15mol / L HNO3; The fourth dissolution step specifically includes: adding 4 mL of saturated boric acid solution and evaporating to dryness at 120° C. to eliminate residual HF in the sample digestion process; The fifth dissolution step specifically includes: adding 4 mL of 10 mol / L HNO3 to dissolve the sample, and keeping the sample at 120°C for 4 hours to obtain a sample solution dissolved in 10 mol / L HNO3.

3. The Sr-Nd-Hf separation method according to claim 1, characterized in that: If the sample solution is a high-content sample, it is divided into three parts, and analyzed using SR leaching resin mini exchange column, DGA leaching resin mini exchange column, and UTEVA leaching resin mini exchange column, respectively, including: dividing the high-content sample into a first part, a second part, and a third part; The first part is loaded onto the SR leaching resin mini exchange column for elution, and then analyzed using 0.45 mol / L HNO3 to obtain an elemental analysis solution of Sr; The second part is loaded onto the DGA leaching resin mini exchange column for elution, and then eluted with 2.6 mol / L HCl and analyzed with 1.8 mol / L HCl in sequence to obtain an elemental analysis solution of Nd; The third part is loaded onto the UTEVA leaching resin mini exchange column for elution, and then analyzed using 4.5 mol / L HNO3 to obtain an elemental analysis solution of Hf.

4. The Sr-Nd-Hf separation method according to claim 3, characterized in that: The SR leaching resin mini exchange column is prepared by filling 1±0.1 mL of 50-100 µm SR leaching resin in a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end; The UTEVA leaching resin mini exchange column is prepared by filling 1±0.1 mL of 50-100µm UTEVA leaching resin into a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end; The DGA leaching resin mini exchange column is prepared by uniformly mixing 0.5±0.1 mL 50-100µm and 0.5±0.1 mL 100-200µm DGA leaching resin and then filling the mixture into a Poly-Prep chromatography empty column with an inner diameter of 5mm and a porous polyethylene gasket at the lower end.

5. The Sr-Nd-Hf separation method according to claim 4, characterized in that: The SR leaching resin mini exchange column is prepared by filling 1 mL of 50-100 μm SR leaching resin into a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end; The UTEVA leaching resin mini exchange column is prepared by filling 1 mL of 50-100 μm UTEVA leaching resin into a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end; The DGA leaching resin mini exchange column is prepared by uniformly mixing 0.5 mL 50-100 µm and 0.5 mL 100-200 µm DGA leaching resin and then filling the mixture into a Poly-Prep chromatography empty column with an inner diameter of 5 mm and a porous polyethylene gasket at the lower end.

6. The Sr-Nd-Hf separation method according to claim 3, characterized in that: The step of loading the first part onto the SR leaching resin mini exchange column for elution specifically comprises: The SR leaching resin mini exchange column is pre-cleaned with 10-20 mL 0.05 mol / L HCl and 10-30 mL high-purity water in sequence; Add 3-5 mL 10-12 mol / L HNO3 to the SR leaching resin mini exchange column for equilibrium; The first part is diluted to 3-5 mL with 10-12 mol / L HNO3 and then loaded into the SR leaching resin mini exchange column; 3-6mL 10-12mol / L HNO3 was used to elute the matrix elements and the interfering element Rb of Sr.

7. The Sr-Nd-Hf separation method according to claim 6, characterized in that: The step of loading the first part onto the SR leaching resin mini exchange column for elution more specifically includes: The SR leaching resin mini exchange column was pre-cleaned with 10 mL 0.05 mol / L HCl and 20 mL high-purity water respectively; Add 3 mL of 10 mol / L HNO3 to the SR leaching resin mini exchange column for equilibrium; The first part is diluted to 4 mL with 10 mol / L HNO3 and then loaded into the SR leaching resin mini exchange column; 3 mL 10 mol / L HNO3 was used to elute the matrix elements and the interfering element Rb of Sr.

8. The Sr-Nd-Hf separation method according to claim 3, characterized in that: The step of loading the second part onto the DGA leaching resin mini exchange column for elution specifically comprises: The DGA leaching resin mini exchange column is pre-cleaned with a mixture of 10-20 mL 0.05 mol / L HNO3 and 1.5 mol / L HF, and 10-30 mL high-purity water in sequence; Add 3-5 mL 10-12 mol / L HNO3 to the DGA leaching resin mini exchange column for equilibrium; The second part is diluted to 3-5 mL with 10-12 mol / L HNO3 and then loaded into the DGA leaching resin mini exchange column; Use 3-6mL 10-12mol / L HNO3 to elute the matrix elements.

9. The Sr-Nd-Hf separation method according to claim 8, characterized in that: The step of loading the second part onto the DGA leaching resin mini exchange column for elution more specifically comprises: The DGA leaching resin mini exchange column was pre-cleaned with a mixture of 10 mL 0.05 mol / L HNO3 and 1.5 mol / L HF and 20 mL high-purity water in sequence; Add 3 mL of 10 mol / L HNO3 to the DGA leaching resin mini exchange column for equilibration; The second part is diluted to 4 mL with 10 mol / L HNO3 and then loaded into the DGA leaching resin mini exchange column; Matrix elements were eluted using 3 mL 10 mol / L HNO3.

10. The Sr-Nd-Hf separation method according to claim 3, characterized in that: The step of loading the third part onto the UTEVA leaching resin mini exchange column for elution specifically comprises: The UTEVA leaching resin mini exchange column is pre-cleaned with 10-20 mL 0.05 mol / L HCl and 10-30 mL high-purity water in sequence; Add 3-5 mL 10-12 mol / L HNO3 to the UTEVA leaching resin mini exchange column for equilibrium; The third part is diluted to 3-5 mL with 10-12 mol / L HNO3 and then loaded into the UTEVA leaching resin mini exchange column; 3-6mL 10-12mol / L HNO3 was used to elute the matrix elements and the interfering elements Lu and Yb of Hf.

11. The Sr-Nd-Hf separation method according to claim 10, characterized in that: The step of loading the third part onto the UTEVA leaching resin mini exchange column for elution more specifically comprises: The UTEVA leaching resin mini exchange column was pre-cleaned with 10 mL 0.05 mol / L HCl and 20 mL high-purity water in sequence; Add 3 mL 10 mol / L HNO3 to the UTEVA leaching resin mini exchange column for balance; The third part was diluted to 4 mL with 10 mol / L HNO3 and then loaded into the UTEVA leaching resin mini exchange column; 3 mL 10 mol / L HNO3 was used to elute the matrix elements and the interfering elements Lu and Yb of Hf.

12. The Sr-Nd-Hf separation method according to claim 1, characterized in that: If the sample solution is a low-content sample, a set of columns formed from top to bottom by UTEVA leaching resin mini exchange column, SR leaching resin mini exchange column, and DGA leaching resin mini exchange column is used for analysis, specifically including: Add 3-5 mL 10-12 mol / L HNO3 to the UTEVA leaching resin mini exchange column, the SR leaching resin mini exchange column, and the DGA leaching resin mini exchange column for balance; The UTEVA leaching resin mini exchange column, the SR leaching resin mini exchange column, and the DGA leaching resin mini exchange column are sequentially combined to form a set of columns; After the low-content sample is loaded into the column assembly, 1-2 mL 10-12 mol / L HNO3 is added 3 times to elute the matrix elements and the interfering element Rb; After disassembling the set-column combination, the SR leaching resin mini exchange column was analyzed using 0.45 mol / L HNO3 to obtain an elemental analysis solution of Sr; the DGA leaching resin mini exchange column was eluted with 2.6 mol / L HCl and analyzed with 1.8 mol / L HCl in sequence to obtain an elemental analysis solution of Nd; and the UTEVA leaching resin mini exchange column was analyzed using 4.5 mol / L HNO3 to obtain an elemental analysis solution of Hf.

13. The Sr-Nd-Hf separation method according to claim 3 or 12, characterized in that: The analysis using 0.45 mol / L HNO3 specifically includes: The SR leaching resin mini exchange column is eluted 3-5 times with 2-3 mL 0.45 mol / L HNO3 to analyze the target element Sr and obtain an element analysis solution containing Sr.

14. The separation method according to claim 13, characterized in that: The analysis using 0.45 mol / L HNO3 more specifically includes: The SR elution resin mini exchange column was eluted 4 times with 2 mL 0.45 mol / L HNO 3 to analyze the target element Sr and obtain an element analysis solution containing Sr.

15. The Sr-Nd-Hf separation method according to claim 3 or 12, characterized in that: The steps of eluting with 2.6 mol / L HCl and analyzing with 1.8 mol / L HCl in sequence specifically include: 2-3 mL 2.6 mol / L HCl was added to elute the DGA leaching resin mini exchange column 3 times to elute the interfering elements La, Ce, and Pr, and then 2-3 mL 1.8 mol / L HCl3 was used to elute the DGA leaching resin mini exchange column 3 times to analyze the target element Nd to obtain a receiving solution containing Nd.

16. The Sr-Nd-Hf separation method according to claim 15, characterized in that: The elution with 2.6 mol / L HCl and the analysis with 1.8 mol / L HCl in sequence more specifically include: 2 mL 2.6 mol / L HCl was added to elute the DGA leaching resin mini exchange column 3 times to elute the interfering elements La, Ce, and Pr, and then 2 mL 1.8 mol / L HCl was used to elute the DGA leaching resin mini exchange column 3 times to analyze the target element Nd to obtain a receiving solution containing Nd.

17. The Sr-Nd-Hf separation method according to claim 3 or 12, characterized in that: The analysis using 4.5 mol / L HNO3 specifically includes: 1-2 mL 4.5 mol / L HNO3 was added to elute the UTEVA leaching resin mini exchange column 3-5 times to analyze the target element Hf and obtain an element analysis solution containing Hf.

18. The Sr-Nd-Hf separation method according to claim 17, characterized in that: The analysis using 4.5 mol / L HNO3 more specifically includes: 1 mL 4.5 mol / L HNO3 was added to elute the UTEVA leaching resin mini exchange column 4 times to analyze the target element Hf and obtain an element analysis solution containing Hf.

19. A method for isotope analysis of Sr, Nd, and Hf, characterized in that: The Sr, Nd, and Hf isotope analysis method comprises: performing Sr, Nd, and Hf isotope ratio tests on elemental analysis solutions of Sr, Nd, and Hf using a multi-collector inductively coupled plasma mass spectrometer, wherein the elemental analysis solution of Sr, Nd, and Hf is an elemental analysis solution of Sr, Nd, and Hf obtained by the Sr-Nd-Hf separation method described in any one of claims 1 to 18.

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