A method for determining the content of impurity elements in concentrated isotopes based on HR-ICP-MS

Abstract

The application provides a method for determining the content of impurity elements in concentrated isotopes based on HR-ICP-MS, and belongs to the technical field of element detection. The method provided by the application only needs to consume a small amount of concentrated isotope sample, and is particularly suitable for accurate analysis of the purity of high-value to-be-detected substances such as concentrated isotopes. In the application, the use of element mixed solution series standard substances can realize the simultaneous analysis of 68 kinds of impurity elements, which is significantly superior to the impurity analysis method based on the ICP-MS method in the prior art. The application utilizes an improved matrix effect correction method to realize the correction of the matrix effect through the measurement of the sensitivity factor under the to-be-detected matrix. The application designs a special sample measurement process, measures the process blank without the matrix by the external standard method, and measures the impurity content in the sample by matrix matching, so that the measurement result is more accurate.

Description

Technical Field

[0001] This invention relates to the field of elemental detection technology, and in particular to a method for determining the content of impurity elements in concentrated isotopes based on HR-ICP-MS. Background Technology

[0002] When the isotopic abundance of a material differs from its natural abundance, concentrated isotope materials often exhibit unique properties, leading to wide and important applications in cutting-edge physics detection, electronics, semiconductors, quantum computing, and biomedicine. When concentrated isotopes are used in these applications, their chemical purity is one of the two most critical indicators affecting their performance. Examples include the content of harmful elements in medical concentrated isotopes and the content of impurity elements in concentrated Si and Ge isotopes used in quantum computing and high-performance chips. Therefore, accurate analytical methods for determining the impurity element content in concentrated isotopes are crucial. Among the existing methods for elemental analysis of impurities, glow discharge mass spectrometry (GDMS) can perform direct analysis of all elements of impurities in solid materials, but it requires the analyte to be conductive and has a matrix-matched standard substance, which is difficult to achieve for concentrated isotopes. Neutron activation analysis (NAA) can also perform all-element impurity analysis, but it requires irradiation of the sample, and cost, time, and safety are key factors limiting its widespread application. Other methods such as ICP-OES, AAS, and XRF can also perform multi-element analysis, but their accuracy, detection limit, and spectral interference are all greatly limited.

[0003] Compared with the aforementioned detection methods, high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) offers advantages such as high sensitivity, low detection limit, good precision, wide linear range, high resolution, and the ability to simultaneously analyze multiple elements. Currently, HR-ICP-MS has been applied to the purity analysis of samples such as high-purity titanium dioxide, high-purity rare earth compounds, high-purity metals, and high-purity organic reagents. However, these applications have only performed analysis of a subset of impurity elements (several to twenty or thirty elements), and there are no reports on the simultaneous analysis of 68 impurity elements. Furthermore, there are no reports on the application of HR-ICP-MS to concentrated isotope analysis. Summary of the Invention

[0004] The purpose of this invention is to provide a method for determining the content of impurity elements in concentrated isotopes based on HR-ICP-MS. The method provided by this invention can analyze 68 impurity elements simultaneously using a very small amount of sample, and the measurement results are highly accurate.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for determining the content of impurity elements in concentrated isotopes based on HR-ICP-MS, comprising the following steps:

[0007] (1) After dissolving the concentrated isotope to be tested in a solvent, the sample to be tested is obtained and divided into sample 1, sample 2 and sample 3 of equal volume.

[0008] The matrix in the sample to be tested is 2% HNO3;

[0009] According to the above preparation process of the sample to be tested, except that the concentrated isotope to be tested is not added, the preparation process is blank;

[0010] (2) Use the series of elemental mixed solution standard substances to prepare standard solutions with concentrations of 1 μg / kg, 2 μg / kg, 5 μg / kg and 10 μg / kg, respectively, and denoted as std1~4;

[0011] Prepare a 1 mg / kg mixed elemental standard solution as the spiking stock solution. Prepare solutions with spiking concentrations of 20 μg / kg and 50 μg / kg by weighing, and denote them as std5 and std6, respectively.

[0012] The steps (1) and (2) are not in any particular order;

[0013] (3) High-resolution inductively coupled plasma mass spectrometry was used to measure and analyze the samples 1, 2 and 3 and the process blank obtained in step (1), as well as std1 to 6 obtained in step (2), to obtain the corresponding working curves.

[0014] The measurement sequence is as follows: 2% HNO3, std1, std2, std3, std4, 2% HNO3, process blank, sample 1, sample 2, sample 3, std5, std6;

[0015] (4) Calculate the impurity element content in the process blank based on the working curve of std1-4 obtained in step (3);

[0016] Based on the working curves of samples 1-3 and std5 and 6 obtained in step (3), the content of impurity elements in the sample to be tested is calculated using the measured signal values ​​of samples 1-3 and the sensitivity measured by std5 and 6.

[0017] The difference between the impurity element content in the process blank and the impurity element content in the sample to be tested is divided by the concentration of the concentrated isotope to be tested in the sample to be tested, thus obtaining the impurity element content in the concentrated isotope to be tested.

[0018] Preferably, in step (1), at least one of ultrapure water, pure nitric acid, ammonia, and hydrochloric acid is selected as the solvent according to the different concentrated isotopes to be tested.

[0019] Preferably, in step (1), the mass of the concentrated isotope to be tested is 10 mg, and the concentration of the concentrated isotope to be tested in the sample is 1000 mg / kg.

[0020] Preferably, the series of standard reference materials for the mixed element solution in step (2) conforms to GBW(E)082428~082431.

[0021] Preferably, in step (3), the nuclide with the highest abundance is selected as the impurity element / ion to be tested.

[0022] Preferably, in step (3), the resolution mode of the measurement and analysis is set according to the resolution required to distinguish the interfering ions of the impurity element / analyte ion to be measured.

[0023] Preferably, when the required resolution is <400, a low-resolution mode is set; when the required resolution is 400 to 4000, a medium-resolution mode is set; and when the required resolution is >4000, a high-resolution mode is set.

[0024] Preferably, the detection parameters of the high-resolution inductively coupled plasma mass spectrometer in step (3) are as follows: RF generator power 1250kW; cooling gas flow rate 16L / min, auxiliary gas flow rate 0.8~1.0L / min, nebulizer gas flow rate 0.9~1.2L / min; injection rate 0.1~0.2mL / min, sampling time 20~100ms / element; accelerating voltage -2kV.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. The method provided by this invention only requires a small amount (10 mg) of concentrated isotope sample, making it particularly suitable for the accurate analysis of the purity of high-value analytes such as concentrated isotopes.

[0027] 2. In this invention, by using a series of elemental mixed solution standard substances (compliant with GBW(E)082428~082431), the simultaneous analysis of 68 impurity elements can be achieved, which is significantly superior to the impurity analysis methods based on ICP-MS in the prior art;

[0028] 3. Matrix effects can severely affect the accuracy of ICP-MS measurement results. Standard addition requires the spiked concentration to match the concentration of the analyte. However, the impurity content in concentrated isotopes is unknown and varies in concentration, making it difficult to measure using the traditional standard addition method. This invention achieves matrix effect correction by measuring the sensitivity factor under the analyte matrix through an improved matrix effect correction method.

[0029] 4. This invention designs a special sample testing process, which measures the matrix-free process blank by external standard method and measures the impurity content in the sample by matrix matching, resulting in more accurate measurement results. Attached Figure Description

[0030] Figure 1 This is a statistical graph showing the matrix inhibition efficiency of Yb solutions of different concentrations in this invention.

[0031] Figure 2 This is a statistical chart showing the matrix inhibition efficiency of a 1000 mg / kg Ge solution in this invention.

[0032] Figure 3 This is a statistical chart showing the matrix inhibition efficiency of the 3500 mg / kg Mo solution in this invention;

[0033] Figure 4 This is a statistical chart showing the matrix inhibition efficiency of the 1300 mg / kg Ni solution in this invention.

[0034] Figure 5 This is a statistical chart showing the matrix inhibition efficiency of the 1500 mg / kg Y solution in this invention;

[0035] Figure 6 This is a statistical chart showing the matrix inhibition efficiency of a 1000 mg / kg Zn solution in this invention. Detailed Implementation

[0036] This invention provides a method for determining the content of impurity elements in concentrated isotopes based on HR-ICP-MS, comprising the following steps:

[0037] (1) After dissolving the concentrated isotope to be tested in a solvent, the sample to be tested is obtained and divided into sample 1, sample 2 and sample 3 of equal volume.

[0038] The matrix in the sample to be tested is 2% HNO3;

[0039] According to the above preparation process of the sample to be tested, except that the concentrated isotope to be tested is not added, the preparation process is blank;

[0040] (2) Use the series of elemental mixed solution standard substances to prepare standard solutions with concentrations of 1 μg / kg, 2 μg / kg, 5 μg / kg and 10 μg / kg, respectively, and denoted as std1~4;

[0041] Prepare a 1 mg / kg mixed elemental standard solution as the spiking stock solution. Prepare solutions with spiking concentrations of 20 μg / kg and 50 μg / kg by weighing, and denote them as std5 and std6, respectively.

[0042] The steps (1) and (2) are not in any particular order;

[0043] (3) High-resolution inductively coupled plasma mass spectrometry was used to measure and analyze the samples 1, 2 and 3 and the process blank obtained in step (1), as well as std1 to 6 obtained in step (2), to obtain the corresponding working curves.

[0044] The measurement sequence is as follows: 2% HNO3, std1, std2, std3, std4, 2% HNO3, process blank, sample 1, sample 2, sample 3, std5, std6;

[0045] (4) Calculate the impurity element content in the process blank based on the working curve of std1-4 obtained in step (3);

[0046] Based on the working curves of samples 1-3 and std5 and 6 obtained in step (3), the content of impurity elements in the sample to be tested is calculated using the measured signal values ​​of samples 1-3 and the sensitivity measured by std5 and 6.

[0047] The difference between the impurity element content in the process blank and the impurity element content in the sample to be tested is divided by the concentration of the concentrated isotope to be tested in the sample to be tested, thus obtaining the impurity element content in the concentrated isotope to be tested.

[0048] In this invention, the concentrated isotope to be tested is dissolved in a solvent to obtain the sample to be tested, and then divided into three samples of equal volume: sample 1, sample 2, and sample 3.

[0049] In this invention, the concentrated isotope to be tested preferably includes at least one of Li, B, Mg, Si, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Se, Rb, Sr, Y, Zr, Nb, Mo, Rh, Pd, Ag, Cd, Sn, Sb, Te, Ba, rare earth elements, Hf, Ta, W, Re, Os, Ir, Pt, Hg, Pb, and U.

[0050] In this invention, at least one of ultrapure water, nitric acid, ammonia, and hydrochloric acid is preferred as the solvent depending on the different concentrated isotopes to be tested.

[0051] In this invention, the mass of the concentrated isotope to be tested is preferably 10 mg, and the concentration of the concentrated isotope to be tested in the sample to be tested is preferably 1000 mg / kg.

[0052] The present invention follows the above-mentioned preparation process of the sample to be tested, except that the concentrated isotope to be tested is not added, and the preparation process is blank.

[0053] The present invention utilizes the process blank for background subtraction of the sample to be tested.

[0054] In this invention, a series of elemental mixed solution standard substances are used to prepare standard solutions with concentrations of 1 μg / kg, 2 μg / kg, 5 μg / kg and 10 μg / kg, respectively, and are denoted as std1 to std4. A 1 mg / kg elemental mixed solution standard substance is prepared as the spiking stock solution, and solutions with spiking concentrations of 20 μg / kg and 50 μg / kg are prepared by weighing, respectively, and are denoted as std5 and std6.

[0055] In this invention, there is no specific order in which the test sample and std1 to 6 are prepared.

[0056] In this invention, the series of standard reference materials for the mixed element solution preferably conforms to GBW(E)082428~082431.

[0057] In this invention, standard substances are prepared by using a series of elemental mixed solution standard substances conforming to GBW(E)082428~082431, which enables the simultaneous analysis of 68 impurity elements.

[0058] This invention uses a high-resolution inductively coupled plasma mass spectrometer to measure and analyze the samples 1, 2, and 3, the process blank, and std1 to std6, and obtain the corresponding working curves.

[0059] The measurement sequence is as follows: 2% HNO3, std1, std2, std3, std4, 2% HNO3, process blank, sample 1, sample 2, sample 3, std5, std6.

[0060] This invention sets the order of the above measurements to avoid the influence of the sample matrix on the process blank measurement, and at the same time avoids the influence of the added standards on the sample measurement, so that the measurement can be carried out continuously, reducing cleaning time and improving measurement efficiency.

[0061] In this invention, before the measurement and analysis, it is preferable to replace the cleaned nickel cone to reduce instrument background interference. The instrument sensitivity and resolution are tuned using a 1 ng / g mixed standard solution (GBW(E)130242) so that the In count is above 1 million in low resolution mode, the resolution in medium resolution mode is better than 4000, and the resolution in high resolution mode is better than 9000.

[0062] In this invention, the nuclide with the highest abundance is preferably selected as the impurity element / ion to be tested.

[0063] In this invention, the resolution mode of the measurement and analysis is preferably set according to the resolution required to distinguish the interfering ions of the impurity element / analyte ion to be measured.

[0064] In this invention, when the required resolution is <400, a low resolution mode is preferably set; when the required resolution is 400 to 4000, a medium resolution mode is preferably set; when the required resolution is >4000, a high resolution mode is preferably set.

[0065] In this invention, when the measurement and analysis process is blank and std1-6, it is preferable to set the same resolution mode as samples 1-3.

[0066] In this invention, the preferred detection parameters of the high-resolution inductively coupled plasma mass spectrometer are: RF generator power 1250kW; cooling gas flow rate 16L / min, auxiliary gas flow rate 0.8~1.0L / min, nebulizer gas flow rate 0.9~1.2L / min; injection rate 0.1~0.2mL / min, sampling time 20~100ms / element; accelerating voltage -2kV.

[0067] After obtaining the corresponding working curves, the present invention calculates the impurity element content in the process blank based on the measured working curves of std1-4, and calculates the impurity element content in the sample to be tested based on the measured working curves of samples 1-3 and std5, 6 using the measured signal values ​​of samples 1-3 and the sensitivity measured by std5, 6; the difference between the impurity element content in the process blank and the impurity element content in the sample to be tested is divided by the concentration of the concentrated isotope to be tested in the sample to be tested to obtain the impurity element content in the concentrated isotope to be tested.

[0068] This invention employs a novel matrix effect correction method, setting up different measurement modes for process blanks and samples, which significantly improves the accuracy of measurement results.

[0069] This invention requires only 10mg of sample, making it particularly suitable for the analysis of high-value samples such as concentrated isotopes. By combining low, medium, and high resolution modes, it can completely separate different analytes from their interfering ions, enabling simultaneous detection. The use of existing multi-element mixed standard solutions GBW(E)082428~082431 ensures the accuracy and traceability of measurement results. Matrix effects can be overcome through methods such as the standard addition method, achieving accurate measurement.

[0070] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0071] The invention used in Embodiment 1 176 The Yb concentrated isotope sample was purchased from the market.

[0072] Example 1

[0073] A method for determining the content of impurity elements in concentrated isotopes based on HR-ICP-MS, comprising the following steps:

[0074] (1) Accurately weigh 10 mg using a high-precision balance (Mettler-Toledo, 0.01 mg). 176 The concentrated Yb isotope sample was placed in a cleaned PFA container, and 1 mL of ultrapure water and 0.2 mL of concentrated nitric acid were added. The sample was heated to dissolve, and finally, the volume was adjusted to a final volume using ultrapure water. 176 The sample to be tested has a concentration of Yb concentrated isotope of 1000 mg / kg;

[0075] The matrix in the sample to be tested is 2% HNO3;

[0076] According to the above preparation process of the sample to be tested, except that no concentrated isotope to be tested is added and the preparation process is blank, all the processing procedures are the same as those of the sample to be tested. This blank process is used for background subtraction of the sample.

[0077] (2) Using a series of mixed elemental solution standard substances (compliant with GBW(E)082428~082431), standard solutions with concentrations of 1 μg / kg, 2 μg / kg, 5 μg / kg and 10 μg / kg were prepared and designated as std1~4 respectively; at the same time, a 1 mg / kg mixed elemental solution standard substance was prepared as a spiking stock solution, and solutions with spiking concentrations of 20 μg / kg and 50 μg / kg were prepared by weighing and designated as std5 and std6 respectively, for matrix effect correction;

[0078] The steps (1) and (2) are not in any particular order;

[0079] (3) High-resolution inductively coupled plasma mass spectrometry was used to measure and analyze the samples 1, 2 and 3 and the process blank obtained in step (1), as well as std1 to 6 obtained in step (2), to obtain the corresponding working curves.

[0080] The nuclide with the highest abundance is selected as the impurity element / analyte ion to be measured. The resolution mode of the measurement and analysis is set according to the resolution energy required to distinguish the interfering ions of the impurity element / analyte ion. Specifically: when the resolution energy is <400, a low resolution mode is set; when the resolution energy is 400 to 4000, a medium resolution mode (MR) is set; when the resolution energy is >4000, a high resolution mode (HR) is set; when the measurement and analysis process is blank and std1 to 6, the same resolution mode as samples 1 to 3 is set.

[0081] 176 Table 1 shows the mass number (i.e. the impurity element to be measured) and the resolution used for Yb enriched isotope measurements.

[0082] Table 1. 176 The mass number of each element measured and the resolution mode used in Yb enriched isotope measurements

[0083]

[0084]

[0085] Before the measurement and analysis, the nickel cone was replaced with a clean one to reduce instrument background interference. The instrument sensitivity and resolution were tuned using a 1 ng / g mixed standard solution (GBW(E)130242) to achieve an In count of over 1 million at low resolution, a resolution better than 4000 in medium resolution mode, and a resolution better than 9000 in high resolution mode. The optimized HR-ICP-MS detection parameters are shown in Table 2.

[0086] Table 2 176 HR-ICP-MS operating parameters for Yb concentrated isotope measurements

[0087]

[0088] Other detection parameters of the high-resolution inductively coupled plasma mass spectrometer are: injection rate 0.1 mL / min, sampling time 20 ms / element; accelerating voltage -2 kV;

[0089] The measurement sequence is as follows: 2% HNO3, std1, std2, std3, std4, 2% HNO3, process blank, sample 1, sample 2, sample 3, std5, std6;

[0090] (4) Calculate the impurity element content in the process blank based on the working curves of std1-4 obtained in step (3). Based on the working curves of samples 1-3 and std5 and 6 obtained in step (3), calculate the impurity element content in the sample to be tested using the measured signal values ​​of samples 1-3 and the sensitivity (i.e., slope) measured by std5 and 6. The difference between the impurity element content in the process blank and the impurity element content in the sample to be tested is divided by the concentration of the prepared sample solution to obtain the impurity element content in the sample. The final detection results are shown in Table 3.

[0091] Table 3 Detection in Example 1 176 Statistical results of Yb concentrated isotopes

[0092]

[0093] Investigation 1: The suppressive effect of matrix effect on impurity measurement results

[0094] To investigate the suppressive effect of matrix effect on impurity measurement results, test samples with different concentrations and matrices were prepared using the same method as in Example 1. The test samples were then measured and analyzed using the method described in Example 1. The slope of the working curves measured at std1-4 was defined as R1, and the slope of the curves measured at std5-6 as R2. The matrix suppression efficiency was defined as... The inhibition efficiency of different matrices was then detected and calculated, such as... Figures 1-6 As shown.

[0095] Following the same method as in Example 1, Yb solutions with concentrations of 100 mg / kg, 500 mg / kg, 600 mg / kg, 1000 mg / kg, 2000 mg / kg, 3000 mg / kg, and 4000 mg / kg were measured and analyzed. The matrix inhibition efficiency of Yb solutions at different concentrations is shown in the following statistical graph. Figure 1 As shown. By Figure 1 It can be seen that for Yb, the higher the matrix concentration, the stronger the matrix inhibition effect. The strength of inhibition is related to the element. If no way is found to overcome it, it will significantly affect the accuracy of the measurement results.

[0096] Following the same method as in Example 1, the Ge solution with a concentration of 1000 mg / kg was measured and analyzed, and the matrix inhibition efficiency of the 1000 mg / kg Ge solution was statistically analyzed as shown in the figure below. Figure 2 As shown. By Figure 2 It can be seen that the Ge matrix has a significant suppression effect on the signals of other impurity elements. The strength of the suppression is related to the element. If it is not corrected, it will affect the accuracy of the measurement results.

[0097] Following the same method as in Example 1, the 3500 mg / kg Mo solution was measured and analyzed, and the matrix inhibition efficiency of the 3500 mg / kg Mo solution was statistically analyzed as shown in the following figure. Figure 3 As shown. By Figure 3 It can be seen that the Mo matrix has a significant suppression effect on the signals of other impurity elements. The strength of the suppression is related to the element. If it is not corrected, it will affect the accuracy of the measurement results.

[0098] Following the same method as in Example 1, the 1300 mg / kg Ni solution was measured and analyzed, and the matrix inhibition efficiency of the 1300 mg / kg Ni solution was statistically analyzed as shown in the following figure. Figure 4 As shown. By Figure 4 It can be seen that the Ni matrix has a significant suppression effect on the signals of other impurity elements. The strength of the suppression is related to the element. If it is not corrected, it will affect the accuracy of the measurement results.

[0099] Following the same method as in Example 1, the 1500 mg / kg Y solution was measured and analyzed, and the matrix inhibition efficiency of the 1500 mg / kg Y solution was statistically analyzed as shown in the following figure. Figure 5 As shown. By Figure 5 It can be seen that the matrix of Y has a significant suppression effect on the signals of other impurity elements. The strength of the suppression is related to the element. If it is not corrected, it will affect the accuracy of the measurement results.

[0100] Following the same method as in Example 1, the 1000 mg / kg Zn solution was measured and analyzed, and the matrix inhibition efficiency of the 1000 mg / kg Zn solution was statistically analyzed as shown in the following figure. Figure 6 As shown. By Figure 6 It can be seen that the Zn matrix has a significant suppression effect on the signals of most impurity elements. The strength of the suppression is related to the element. If it is not corrected, it will affect the accuracy of the measurement results.

[0101] In summary, it can be seen that the matrix effect varies for different elements; for the same element, the matrix effect increases with increasing matrix concentration; and under the same matrix, the matrix inhibition effect of different elements also varies slightly.

[0102] Investigation 2: Spiked Recovery Experiment

[0103] To verify the detection effect of the method provided by this invention on 68 impurity elements, a high-purity ytterbium oxide sample was used as an example. A mixed standard solution of 68 impurity elements with a concentration of 10 ng / g and a solution with a concentration of 500 μg / g were prepared as the sample solution to be tested. The content of impurity elements in the solution before and after spiking was measured by the external standard method (as a comparative example) and the method of Example 1 of this invention (i.e., matrix matching method, as Example 2). The recovery rate is shown in Table 3.

[0104] The external standard method was used for measurement. The specific steps were as follows: standard solutions with concentrations of 1 μg / kg, 2 μg / kg, 5 μg / kg and 10 μg / kg were prepared using a series of elemental mixed solution standard substances (compliant with GBW(E)082428~082431), and were denoted as std1~4 respectively; the impurity element content of the sample was calculated by measuring in the following order: 2% HNO3, std1, std2, std3, std4, 2% HNO3, process blank, sample 1, sample 2 and sample 3. The working curves obtained by std1~4 and the signal measurement values ​​of the sample were used to calculate the impurity element content of the sample.

[0105] Table 4. Results of spiked recovery experiments of 68 impurity elements in ytterbium oxide solution at 4500 μg / g.

[0106]

[0107]

[0108] As shown in Table 4, the external standard method for measuring impurity elements in concentrated isotopes is difficult to achieve satisfactory accuracy due to the influence of the sample matrix (the recovery rate of the external standard method is about 50% at a matrix of 500 mg / kg). However, through matrix matching correction of this method, satisfactory recovery data were obtained, indicating that this method can better overcome the matrix effect, accurately measure the content of impurity elements in concentrated isotopes, and improve the accuracy of the measurement results.

[0109] In summary, the method provided by this invention can obtain the content of 68 impurity elements using a very small amount of sample. Furthermore, the novel matrix effect correction method provided by this invention allows for the measurement of process blanks and samples using different measurement modes, thereby improving the accuracy of the measurement.

[0110] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the content of impurity elements in concentrated isotopes based on HR-ICP-MS, characterized in that, The method comprises the following steps: (1) dissolving the to-be-tested concentrated isotopes in a solvent to obtain a to-be-tested sample, and dividing the to-be-tested sample into sample 1, sample 2 and sample 3 with equal volume; the matrix in the to-be-tested sample is 2% HNO3; according to the preparation process of the to-be-tested sample, a blank sample is prepared without adding the to-be-tested concentrated isotopes; (2) using element mixed solution series standard substances to prepare standard solutions with concentrations of 1 μg / kg, 2 μg / kg, 5 μg / kg and 10 μg / kg, which are denoted as std1-4 respectively; 1 mg / kg of the element mixed solution standard substance is prepared as a standard mother liquor, and solutions with standard concentrations of 20 μg / kg and 50 μg / kg are prepared by weighing, which are denoted as std5 and std6 respectively; the steps (1) and (2) have no sequence; (3) using a high-resolution inductively coupled plasma mass spectrometer to measure and analyze sample 1, sample 2, sample 3 and the blank sample obtained in the step (1) and std1-6 obtained in the step (2) to obtain corresponding working curves; the sequence of the measurement is as follows: 2% HNO3, std1, std2, std3, std4, 2% HNO3, blank sample, sample 1, sample 2, sample 3, std5, std6; (4) calculating the content of impurity elements in the blank sample according to the working curves of std1-4 measured in the step (3); using the signal values of sample 1-3 measured in the step (3) and the working curves of std5 and std6, the content of impurity elements in the to-be-tested sample is calculated; the difference between the content of impurity elements in the blank sample and the content of impurity elements in the to-be-tested sample is divided by the concentration of the to-be-tested concentrated isotopes in the to-be-tested sample to obtain the content of impurity elements in the to-be-tested concentrated isotopes; The slope of the working curve measured for std 1-4 is R1, while the slope of the working curve measured for std 5-6 is R2, and the matrix suppression efficiency is defined as .

2. The method of claim 1, wherein, in the step (1), at least one of ultrapure water, nitric acid, ammonia and hydrochloric acid is selected as the solvent according to the different to-be-tested concentrated isotopes.

3. The method of claim 1, wherein, in the step (1), the mass of the to-be-tested concentrated isotopes is 10 mg, and the concentration of the to-be-tested concentrated isotopes in the to-be-tested sample is 1000 mg / kg.

4. The method of claim 1, wherein, in the step (2), the element mixed solution series standard substances meet GBW(E)082428-082431.

5. The method of claim 1, wherein, in the step (3), the nuclide with the highest abundance is selected as the to-be-tested impurity element / to-be-tested ion.

6. The method of claim 5, wherein, in the step (3), the resolution mode of the measurement and analysis is set according to the required resolution energy of the interference ion for distinguishing the to-be-tested impurity element / to-be-tested ion.

7. The method of claim 6, wherein, when the required resolution energy is <400, a low-resolution mode is set; when the required resolution energy is 400-4000, a medium-resolution mode is set; and when the required resolution energy is >4000, a high-resolution mode is set.

8. The method of claim 1, wherein, The detection parameters of the high-resolution inductively coupled plasma mass spectrometer in the step (3) are as follows: radio frequency generator power 1250 kW; cooling gas flow rate 16 L / min, auxiliary gas flow rate 0.8-1.0 L / min, atomizing gas flow rate 0.9-1.2 L / min; sample injection rate 0.1-0.2 mL / min, sampling time 20-100 ms / element; acceleration voltage -2 kV.

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