Rapid high-precision determination method for reduction-state Os isotope

Abstract

The invention provides a rapid and high-precision determination method for reduction-state Os isotope. The method comprises the following steps: selecting a sample to be detected and carrying out ultrafine crushing; weighing the ground to-be-detected sample, and sealing and dissolving the sample; taking out the dissolved to-be-detected sample, and adding isometric hydrobromic acid to convert oxidation state Os into reduction state Os; carrying out acid removal and constant volume on the reduced-state Os solution; establishing a cup structure for static determination of the Os isotope, and performing MC-ICP-MS determination of the reduction state Os isotope according to the cup structure. According to the present invention, the dissolved to-be-tested sample is creatively taken out, and the isometric hydrobromic acid is added so as to convert the oxidation state Os into the reduction state Os, such that the memory effect can be substantially reduced, the efficiency can be improved, the research cost and the research time can be reduced when the MC-ICP-MS is adopted to rapidly and precisely measure the Os isotope, and the method is suitable for the mass sample test.

Description

Technical Field

[0001] This invention belongs to the technical field of osmium isotope tracing and dating, specifically relating to a rapid and high-precision method for determining reduced Os isotopes. Background Technology

[0002] In cosmochemistry and geochemistry research, due to the ratio of the three isotopes of Os... 184 Os / 188 Os、 186 Os / 188 Os and 187 Os / 188 Os and 184 Os- 180 W, 190 Pt- 186 Os, and 187 Re- 187 The three radioactive isotopes of Os are related and of great research significance, and the high-precision determination of these ratios is particularly important. Currently, the main instruments used for high-precision determination of Os isotopes are multi-receiver inductively coupled plasma mass spectrometry (MC-ICPMS) and thermal ionization mass spectrometry (TIMS). The two instruments operate on the same principle, differing only in the sample introduction method: MC-ICPMS uses liquid sample introduction, while TIMS uses solid sample introduction. The advantages of MC-ICP-MS over TIMS are: 1) Elements are determined using X... + 1) Measurement in the form of ions, therefore no determination of O isotope composition is required; 2) W and Re are easily and accurately calibrated; 3) Analysis is fast, even for high-precision applications. 186 Os measurement; 4) No Pt filament material is required, making the analysis relatively inexpensive; High-precision and high-accuracy determination of Os isotopes requires two conditions: 1) Accurate determination of all osmium isotopes (7 in total); 2) Accurate determination of isotopic interferences of osmium isotopes (e.g.: 187 Re to 187 Os interference; 186 W to 186 (Os interference).

[0003] Currently, the main methods for measuring Os isotopes include: thermal ionization mass spectrometry (TIMS) for determining osmium isotopes, interfering element isotopes, and oxygen isotopes under negative ion conditions; and MC-ICPMS for high-precision measurement of oxidized Os isotopes. The problems with TIMS are: 1) the pre-analytical chemical procedures are more complex than MC-ICP-MS; 2) Os is analyzed as OsO3-, requiring deoxygenation correction of the measurement results; 3) mass fractionation changes over time; 4) the analysis speed is slow, time-consuming and labor-intensive; and 5) the use of Pt tapes is expensive. The problems with MC-ICP-MS are: traditional MC-ICP-MS measures oxidized Os isotopes using conventional solution nebulization injection. While this injection method is simple, the strong memory effect of oxidized Os allows it to penetrate into the inner wall of the plastic, making it difficult to remove. Another wet injection method involves removing the solvent water from the membrane at a high temperature (160) °C, and then using a high-flow-rate carrier gas to introduce the solute into the instrument as an aerosol. However, the problem remains that the Os memory effect is very strong. Due to the Os memory effect, neither of the above two injection methods can continuously measure Os isotopes.

[0004] To address the aforementioned issues, it is necessary to propose a well-designed and effective method for the rapid and high-precision determination of reduced Os isotopes. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art, and to provide a rapid and high-precision method for the determination of reduced Os isotopes.

[0006] This invention provides a rapid and high-precision method for determining reduced Os isotopes, the method comprising: Step 1: Select the sample to be tested and perform ultrafine grinding; Step 2: Weigh the ground sample to be tested and seal it for dissolution. Step 3: Take out the dissolved sample and add an equal volume of hydrobromic acid to convert the oxidized Os to the reduced Os. Step 4: Remove acid and bring the volume of the reduced Os solution to a final level; Step 5: Establish a cup structure for static determination of Os isotopes, and perform MC-ICP-MS determination of reduced Os isotopes based on the cup structure.

[0007] Optionally, in step three, an equal volume of hydrobromic acid is added to convert oxidized Os to reduced Os, including: Add an equal volume of hydrobromic acid to the dissolved sample and place it in an oven to keep it warm, so that osmium tetroxide can be fully converted into hexabromoosmium acid.

[0008] Optionally, place it in an oven and keep it at 80℃~100℃ for 2h~3h.

[0009] Optionally, step four involves acid removal and volume adjustment of the reduced Os solution, including: Add hydrochloric acid solution and place the reduced Os solution on an electric heating plate to remove the acid, then make up the volume with hydrochloric acid and ethanol solution.

[0010] Optionally, add 6 mol / L hydrochloric acid solution and place the reduced Os solution on an electric heating plate and heat it at 180℃~200℃ to remove nitric acid and hydrobromic acid from the solution; When 0.5 mL of solution remains, add 1 mol / L hydrochloric acid solution to convert hexabromoosmium acid to hexachloroosmium acid.

[0011] Optionally, in step two, the ground sample to be tested is weighed and sealed for dissolution, including: Weigh the sample to be tested, add it to a glass tube, and heat it in aqua regia at 230℃~250℃ for 48h~50h to dissolve the sample in a sealed container.

[0012] Optionally, step five involves establishing the cup structure for static Os isotope determination, including: 185 The Re ion beam uses the fourth low cup L4 connection 10 11 An Ω amplifier is used for receiving; 187 The Os ion beam uses a third low cup L3 connection 10 11 An Ω amplifier is used for receiving; 188 The Os ion beam uses a second low cup L2 connection 10 11 An Ω amplifier is used for receiving; 189 The Os ion beam uses the first low cup L1 connected to 10 11 An Ω amplifier is used for receiving; 190 The Os ion beam uses a central cup C-connected 10 11 An Ω amplifier is used for receiving; 192 The Os ion beam uses a second high-cup H2 connection 10 11 The Ω amplifier receives the signal.

[0013] Optionally, step one involves selecting the sample to be tested and performing ultrafine grinding, including: Grind the sample to be tested to 200 mesh.

[0014] Optionally, after step five, the method further includes: The measured data were processed offline.

[0015] The present invention provides a rapid and high-precision method for the determination of reduced Os isotopes. It innovatively proposes to add an equal volume of hydrobromic acid to the dissolved sample to convert oxidized Os to reduced Os. This greatly reduces the memory effect, improves efficiency, and reduces research costs and time when using MC-ICP-MS for rapid and high-precision measurement of Os isotopes, making it suitable for testing large quantities of samples. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating a wind turbine data recording method according to an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating the time required for the Os signal value to decrease to the background signal value in different media according to another embodiment of the present invention. Figure 3 This is a schematic diagram showing the comparative results of measuring GangOs and LiuOs samples using MC-ICP-MS and TIMS, respectively, in another embodiment of the present invention. Figure 4 This is a schematic diagram of the repeatability test results of GangOs, LiuOs, and STDOs in another embodiment of the present invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Traditional MC-ICP-MS is used to determine oxidized Os isotopes, employing conventional solution nebulization for injection. While this method is simple, the strong Os memory effect causes the Os residue to penetrate the inner wall of the plastic membrane, making it difficult to remove. Another wet injection method involves removing the solvent water from the membrane at a high temperature (160°C), followed by introducing the solute as an aerosol using a high-flow-rate carrier gas. However, the strong Os memory effect remains a problem. Both of these injection methods cannot continuously measure Os isotopes due to the Os memory effect.

[0019] To address this, the present invention creatively proposes a rapid and high-precision determination method S100 for reduced Os isotopes, which converts oxidized Os into reduced Os for MC-ICP-MS measurement, greatly reducing the memory effect.

[0020] like Figure 1 As shown, the rapid and high-precision determination method S100 for reduced Os isotopes provided by the present invention may specifically include: Step 1: Select the sample to be tested and perform ultrafine grinding.

[0021] Specifically, the sample to be tested is selected and subjected to ultrafine grinding, preferably grinding the sample to 200 mesh.

[0022] Step 2: Weigh the ground sample and seal it for dissolution.

[0023] Specifically, the weight of the ground sample to be tested is weighed, added to a glass tube, and heated in aqua regia at 230℃~250℃ for 48h~50h to dissolve the sample. In this embodiment, preferably, the weighed sample to be tested is placed in a glass tube, and aqua regia is added and heated at 230℃ for 48 hours to dissolve the sample.

[0024] Step 3: Take out the dissolved sample and add an equal volume of hydrobromic acid to convert the oxidized Os to the reduced Os.

[0025] Specifically, an equal volume of hydrobromic acid is added to the dissolved sample, and the sample is placed in an oven for heat treatment to ensure complete conversion of osmium tetroxide to hexabromoosmium acid. Because hydrobromic acid has a stronger reducing power than hydrochloric acid and reacts more readily with Os, adding an equal volume of hydrobromic acid to the dissolved sample allows for a more effective and complete reduction of osmium tetroxide to hexabromoosmium acid. In other words, it helps to reduce Os... +8 Convert to Os +4 .

[0026] In this embodiment, by adding an equal volume of hydrobromic acid to the dissolved sample and placing it in an oven for heat preservation, osmium tetroxide is fully converted into hexabromoosmium acid, and the oxidized Os is converted into the reduced Os. This greatly reduces the memory effect when using MC-ICP-MS to measure the reduced Os isotopes quickly and with high precision.

[0027] Preferably, in this embodiment, the solution containing hydrobromic acid is placed in an oven and kept at 80°C to 100°C for 2 to 3 hours. More preferably, the solution containing hydrobromic acid is placed in an oven and kept at 80°C for 2 hours.

[0028] In this embodiment, the solution containing hydrobromic acid is placed in an oven and kept at 80℃~100℃ for 2h~3h, which can better convert the oxidized Os to the reduced Os, thus preparing for the rapid and high-precision measurement of the reduced Os isotopes.

[0029] Step 4: Remove acid from the reduced Os solution and bring it to volume.

[0030] Specifically, hydrochloric acid solution is added and the reduced Os solution is placed on an electric heating plate for heating to remove the acid, and then the volume is adjusted with hydrochloric acid and ethanol solution.

[0031] More specifically, firstly, a 6 mol / L hydrochloric acid solution is added, and the reduced Os solution is placed on an electric heating plate and heated at 180℃~200℃ to remove nitric acid and hydrobromic acid from the solution. Since nitric acid oxidizes Os and hydrobromic acid can damage the instrument, these substances are removed during heating by utilizing their different boiling points.

[0032] Secondly, when 0.5 mL of solution remains, add 1 mol / L hydrochloric acid solution to convert hexabromoosmium acid to hexachloroosmium acid.

[0033] In this embodiment, although hexabromoosmium tetroxide (Os) is stable in an acidic environment, its bromide form may cause side reactions or interference during subsequent processing or storage. By adding hydrochloric acid to convert it to hexachloroosmium tetroxide (Os), Os becomes more stable in a chlorine medium. Furthermore, the addition of hydrochloric acid facilitates medium conversion, improving compatibility with conventional injection media for MC-ICP-MS (such as dilute hydrochloric acid) and enhancing measurement accuracy.

[0034] Finally, bring the volume up to the required level using a 3% hydrochloric acid and ethanol solution.

[0035] Step 5: Establish a cup structure for static determination of Os isotopes, and perform MC-ICP-MS determination of reduced Os isotopes based on the cup structure.

[0036] Specifically, the cup structure for static determination of Os isotopes is established, including: 185 The Re ion beam uses the fourth low cup L4 connection 10 11 An Ω amplifier is used for receiving; 187 The Os ion beam uses a third low cup L3 connection 10 11 An Ω amplifier is used for receiving; 188 The Os ion beam uses a second low cup L2 connection 10 11 An Ω amplifier is used for receiving; 189 The Os ion beam uses the first low cup L1 connected to 10 11 An Ω amplifier is used for receiving; 190 The Os ion beam uses a central cup C-connected 10 11 An Ω amplifier is used for receiving; 192 The Os ion beam uses a second high-cup H2 connection 10 11 The Ω amplifier receives the signal.

[0037] Table 1. Cup structures determined by static Os isotope analysis.

[0038] Based on the cup structure established for static determination of Os isotopes as shown in Table 1, rapid and high-precision determination of reduced Os isotopes was performed using MC-ICP-MS.

[0039] After completing the rapid and high-precision determination of reduced Os isotopes, the measurement data is processed offline. The data processing process may include: (1) subtracting the interference of Re on Os; (2) correcting the mass fractionation during the instrument measurement process.

[0040] It should be noted that the data processing procedure can refer to the methods commonly used in the existing technology, and will not be described in detail in this embodiment.

[0041] This invention provides a rapid and high-precision method for the determination of reduced Os isotopes, comprising: selecting a sample to be tested and subjecting it to ultrafine grinding; weighing the ground sample and sealing it for dissolution; removing the dissolved sample and adding an equal volume of hydrobromic acid to convert oxidized Os to reduced Os; adjusting the volume of the reduced Os solution by removing the acid; establishing a cup structure for static determination of Os isotopes; and performing MC-ICP-MS determination of reduced Os isotopes based on the cup structure. The invention creatively proposes adding an equal volume of hydrobromic acid to the dissolved sample to convert oxidized Os to reduced Os. This significantly reduces the memory effect, improves efficiency, and reduces research costs and time when using MC-ICP-MS for rapid and high-precision measurement of Os isotopes, making it suitable for large-scale sample testing.

[0042] Next, a specific embodiment will be used to illustrate the specific process and accuracy of the rapid and high-precision determination method for reduced Os isotopes provided by the present invention.

[0043] Three Os standard solutions were selected: GangOs (purchased from the Iron and Steel Research Institute), LiuOs (China University of Geosciences (Beijing)), and STDOs (general Os standard solution). All three standard solutions were in nitric acid medium.

[0044] Because hydrobromic acid has stronger reducing properties than hydrochloric acid and reacts more readily with Os, three standard solutions were diluted to the same concentration, an equal volume of hydrobromic acid was added, and the solutions were placed in an oven at 80°C for 2 hours to allow osmium tetroxide (OsO4) to be fully converted into hexabromoosmium tetroxide (H2OsBr). 6 ), making Os +8 Convert to Os +4 .

[0045] The reacted solution was heated to 180 degrees Celsius on a hot plate. Because nitric acid oxidizes Os and hydrobromic acid can damage the equipment, the nitric acid and hydrobromic acid were removed during heating due to their different boiling points. When approximately 0.5 mL remained, 1 mol / L hydrochloric acid solution was added to convert hexabromoosmium tetroxide (H₂OsBr₆) to hexachloroosmium tetroxide (H₂OsCl₆). Then, as... Figure 2 As shown, the solution after acid removal was diluted to 5 mL with different media solutions before being tested on the instrument, and the strength of the memory effect in different media was evaluated.

[0046] As shown in Table 1, a cup structure for static determination of Os isotopes was established, and MC-ICP-MS was used for rapid and high-precision determination of reduced Os isotopes.

[0047] like Figure 2 As shown, the memory effect of Os in different media was evaluated.

[0048] Previous studies have shown that ethanol maintains the reducing properties of the solution, but the concentration added affects the memory effect of Os in the pipeline. Figure 2 It is evident that the reduced Os in 3% ethanol and hydrochloric acid solutions takes the shortest time to decrease to the background level, requiring only about 5 minutes. This significantly reduces the memory effect of Os in the pipeline, whereas previous MC-ICP-MS measurements of oxidized Os... +8 It may take tens of minutes to remove residual Os from the pipe. Our invention greatly improves the efficiency of MC-ICP-MS measurement of Os isotopes.

[0049] like Figure 3 As shown, measurements were performed using MC-ICP-MS and TIMS respectively, and the measurement results were compared.

[0050] like Figure 3 As shown, the MC-ICP-MS measurement of reduced-state Os and the TIMS results are consistent within the error range. MC-ICP-MS measurement of Gang-Os 187 / 190 Os is 0.05583 ± 0.00005; 192 / 190 Os was 1.55384 ± 0.00016 and 187 / 188 Os was 0.11077 ± 0.00009, while the TIMS measurement result for Gang-Os was... 187 / 190 Os is 0.05579 ± 0.00001; 192 / 190 Os was 1.55389 ± 0.00006 and 187 / 188 The Os value was 0.11068 ± 0.00002. Liu-Os was measured by MC-ICP-MS. 187 / 190 Os is 0.08764 ± 0.00008; 192 / 190 Os was 1.55384 ± 0.00021 and187 / 188 Os was 0.17386 ± 0.00015, while the TIMS measurement result for Liu-Os was... 187 / 190 Os is 0.08765±0.00003; 192 / 190 Os was 1.55391 ± 0.00012 and 187 / 188 The Os value was 0.17388 ± 0.00006. Although TIMS is more accurate than MC-ICP-MS, the results of MC-ICP-MS for measuring reduced Os are consistent with those of TIMS within the error range, and MC-ICP-MS has a faster measurement time and simpler chemical processing before use.

[0051] like Figure 4 As shown, repeatability tests were performed on GangOs, LiuOs, and STDOs samples. Among them, from... Figure 4 As can be seen from the data, in the repeatability tests of GangOs, LiuOs and STDOs, the tests of the two sets of parallel samples were consistent within the error range.

[0052] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A rapid and high-precision method for determining reduced Os isotopes, characterized in that, The method includes: Step 1: Select the sample to be tested and perform ultrafine grinding; Step 2: Weigh the ground sample to be tested and seal it for dissolution. Step 3: Take out the dissolved sample and add an equal volume of hydrobromic acid to convert the oxidized Os to the reduced Os. Step 4: Remove acid and bring the volume of the reduced Os solution to a final level; Step 5: Establish a cup structure for static determination of Os isotopes, and perform MC-ICP-MS determination of reduced Os isotopes based on the cup structure.

2. The method according to claim 1, characterized in that, Step three involves adding an equal volume of hydrobromic acid to convert oxidized Os to reduced Os, including: Add an equal volume of hydrobromic acid to the dissolved sample and place it in an oven to keep it warm, so that osmium tetroxide can be fully converted into hexabromoosmium acid.

3. The method according to claim 2, characterized in that, Place in an oven and keep warm at 80℃~100℃ for 2h~3h.

4. The method according to claim 2, characterized in that, Step four involves removing acid from the reduced Os solution and adjusting the volume, including: Add hydrochloric acid solution and place the reduced Os solution on an electric heating plate to remove the acid, then make up the volume with hydrochloric acid and ethanol solution.

5. The method according to claim 4, characterized in that, Add 6 mol / L hydrochloric acid solution and place the reduced Os solution on an electric heating plate and heat it at 180℃~200℃ to drive away nitric acid and hydrobromic acid in the solution; When 0.5 mL of solution remains, add 1 mol / L hydrochloric acid solution to convert hexabromoosmium acid to hexachloroosmium acid.

6. The method according to any one of claims 1 to 5, characterized in that, Step two involves weighing the ground sample and sealing it for dissolution, including: Weigh the sample to be tested, add it to a glass tube, and heat it in aqua regia at 230℃~250℃ for 48h~50h to dissolve the sample in a sealed container.

7. The method according to any one of claims 1 to 5, characterized in that, Step five involves establishing the cup structure for static determination of Os isotopes, including: 185 The Re ion beam uses the fourth low cup L4 connection 10 11 An Ω amplifier is used for receiving; 187 The Os ion beam uses a third low cup L3 connection 10 11 An Ω amplifier is used for receiving; 188 The Os ion beam uses a second low cup L2 connection 10 11 An Ω amplifier is used for receiving; 189 The Os ion beam uses the first low cup L1 connected to 10 11 An Ω amplifier is used for receiving; 190 The Os ion beam uses a central cup C-connected 10 11 An Ω amplifier is used for receiving; 192 The Os ion beam uses a second high-cup H2 connection 10 11 The Ω amplifier receives the signal.

8. The method according to any one of claims 1 to 5, characterized in that, Step one involves selecting the sample to be tested and performing ultrafine grinding, including: Grind the sample to be tested to 200 mesh.

9. The method according to any one of claims 1 to 5, characterized in that, After step five, the method further includes: The measured data were processed offline.

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