A purification method for strontium isotope detection of silk cultural relics

Abstract

The present invention relates to the technical field of cultural relic detection, and discloses a purification method for detecting strontium isotopes of silk cultural relics, comprising the following steps: (1) enrichment of strontium isotopes: after cleaning the silk cultural relics, adding them into a digester for microwave digestion, and then evaporating and drying; adding the dried product into a nitric acid solution, centrifuging and separating, and extracting the supernatant; (2) purification of strontium isotopes: firstly mixing 4',4''(5'')-di-tert-butyldicyclohexyl-18-crown-6 and a defoaming agent and adsorbing them on a purification resin separation column, and pre-cleaning the separation column with a nitric acid solution; then injecting the supernatant in step (1) into the separation column with the nitric acid solution as a carrier liquid; then, sequentially 84 The Sr solution and the eluent are injected into a separation column to obtain a separated and purified strontium solution. The present invention can eliminate the interference of other impurity ions, reduce the loss of strontium elements, and achieve effective enrichment and purification of strontium elements in silk.

Description

Technical Field

[0001] The present invention relates to the technical field of cultural relic detection, and in particular to a purification method for strontium isotope detection of silk cultural relics. Background Art

[0002] Silk can be considered history's first global commodity. The origins of silk artifacts have been a focus of historians and archaeologists for over a century. Studies of patterns, styles, and weaving techniques on silk artifacts have been a key method for determining silk's origins. However, due to the intermingling of civilizations, these methods cannot provide definitive evidence of silk's origins.

[0003] Currently, using strontium isotopes to trace the origin of silk artifacts is a more accurate methodological system and is also the development direction of scientifically developing isotope technology for tracing the origin of textile artifacts. However, the content of strontium isotopes in silk is very small (<5ppm), and the amount of silk artifact sample required to obtain the strontium content for testing is relatively large. In practice, this is limited by the sample size of the silk artifact itself, coupled with the loss that may occur during the processing process, making it difficult to accurately determine strontium isotopes in silk artifacts. Therefore, before conducting strontium element testing on silk artifacts, targeted purification is very necessary.

[0004] Chinese invention patent publication number CN113433201A discloses a method for sequentially extracting strontium isotopes from silk artifacts. The method uses water, acetic acid, hydrochloric acid, and nitric acid + hydrofluoric acid to sequentially extract silk samples, exploring the distribution patterns of strontium isotopes in various phases. However, this method is limited in that it cannot avoid the influence of interfering ions from other impurities, and significant strontium isotope losses occur during the extraction process, resulting in a low strontium extraction rate in silk artifacts. Summary of the Invention

[0005] In order to solve the problem of targeted purification before strontium element detection in silk cultural relics, the present invention provides a purification method for strontium isotope detection of silk cultural relics, which adopts microwave digestion and solid phase extraction to enrich and purify the strontium element contained in silk, reducing the loss of strontium element while eliminating the interference of other impurity ions to obtain the best purification effect.

[0006] The specific technical solution of the present invention is: the present invention provides a purification method for strontium isotope detection of silk cultural relics, comprising the following steps:

[0007] (1) Strontium isotope enrichment: After cleaning the silk artifacts, add them to a digester for microwave digestion, and then evaporate to dryness; the dried product is added to a nitric acid solution and centrifuged to extract the supernatant;

[0008] (2) Purification of strontium isotopes: First, 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and a defoaming agent are mixed and adsorbed on a purification resin separation column, and the separation column is pre-cleaned with a nitric acid solution, wherein the defoaming agent is tributyl phosphate or n-octanol; then, the supernatant in step (1) is injected into the separation column using a nitric acid solution as a carrier liquid; then, 84 The Sr solution and the eluent are injected into a separation column to obtain a separated and purified strontium solution.

[0009] The present invention first uses microwave digestion to enrich the strontium contained in silk cultural relics. The use of microwave digestion can reduce the time for enriching strontium in silk. In addition, the sample is digested in a closed digestion tank, which can reduce the loss of volatile elements and make the analysis results more accurate. Since the strontium content of silk is relatively low (<5ppm), and during the test process, bubbles are easily generated when the mixed solution containing strontium flows through the separation column, which will reduce the retention of strontium in the separation column. Therefore, a defoaming agent is selected as a defoaming agent to reduce the loss of strontium. In addition, tributyl phosphate and n-octanol can both form organic ligands with 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 to form certain coordination bonds to increase the retention rate of strontium, but the more preferred defoaming agent is tributyl phosphate, because tributyl phosphate can bind to more Sr bond positions and the strontium extraction rate is higher. The organic ligand formed by the separation column is not affected by the pH value of the solution during the separation process and has high stability, which is beneficial to improving the extraction rate of strontium in silk.

[0010] Then, use 84 Sr solution is used as a natural analog of r-Sr to stabilize the purification resin separation column to avoid operational hazards, and finally an eluent is used for elution and separation to obtain a strontium solution. The unified use of nitric acid solution in the enrichment and purification process can avoid the introduction of other impurities, and when nitric acid solution is used as the carrier liquid, strontium has a higher separation coefficient with other ions, achieving a better separation effect. The present invention mainly targets the strontium isotope information of silk, removes the impurity ions that may be contained therein to purify the strontium element contained in the silk. Since the amount of strontium element contained in silk is extremely small, each step in the present invention has a positive effect on the enrichment and purification of the strontium element in silk, especially the concentration, volume and flow rate of the solvent used in each step are all intended to promote the optimal purification effect.

[0011] Preferably, in step (1), the silk cultural relics are cleaned with an ethanol aqueous solution; the volume ratio of ethanol to water in the ethanol aqueous solution is 1 to 2:1; the digester comprises 84 Sr diluent, perchloric acid and hydrofluoric acid.

[0012] As a preference, in step (1), during the microwave digestion, silk cultural relics, 84The mass volume ratio of Sr diluent, perchloric acid and hydrofluoric acid is 1-2 g: 0.05-0.1 g: 10-15 mL: 1-3 mL.

[0013] The present invention uses microwave digestion combined with isotope dilution to enrich strontium in silk, reducing the time required to enrich strontium in silk artifacts and lowering energy consumption. The results are more accurate, reducing the difficulty of strontium isotope analysis in complex samples such as silk artifacts. Furthermore, the acid reagent used in a confined space does not pollute the environment, making it environmentally friendly.

[0014] Preferably, in step (1), the concentration of the nitric acid solution is 1-2 mol / L; the centrifugal separation rate is 3500-4500 r / min, the time is 10-30 min, and the centrifugation is repeated 3-5 times.

[0015] Preferably, in step (2), the concentration of the nitric acid solution during the pre-cleaning is 0.01 to 0.02 mol / L, and the flow rate is 0.5 to 1.0 mL / min; the concentration of the nitric acid solution when used as a carrier liquid is 7 to 10 mol / L, more preferably 8 mol / L, and the flow rate is 0.1 to 0.5 mL / min.

[0016] During the separation process, nitric acid was used as the carrier liquid and the flow rate was strictly controlled to avoid bubbles in the separation column. When the concentration of nitric acid solution was 7-10 mol / L, K + , Ca 2+ Mg 2+ It can also eliminate interfering ions such as Sr and ensure that Sr is retained in the separation column.

[0017] Preferably, in step (2), the mass ratio of the 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 to the defoaming agent is 1 to 2:1; and the purification resin separation column uses 50 to 100 μm Amberchrom CG-71md resin, 80 to 160 μm Amberchrom CG-71cd resin or 100 to 125 μm Amberlite@XAD-7 resin.

[0018] The mass ratio of 4',4" (5") -di-tert-butyldicyclohexyl-18-crown-6 to the defoaming agent ensures that the defoaming agent can be saturated, so that the retention rate of strontium reaches the maximum value of this separation and purification system. If the amount of 4',4" (5") -di-tert-butyldicyclohexyl-18-crown-6 is too little, the retention rate of strontium will be reduced. If the amount of 4',4" (5") -di-tert-butyldicyclohexyl-18-crown-6 is too much and the concentration is too high, the network structure formed will be relatively dense, which is not conducive to the separation of strontium from other ions.

[0019] Preferably, in step (2), the84 The volume of the Sr solution is 4 to 6 mL, and the flow rate of injection into the separation column is 0.2 to 0.5 mL / min.

[0020] After the sample solution is sent to the separation column, in order to ensure the full separation of strontium and other ions, 84 The Sr solution acts as a buffer to wash away any remaining sample solution. 84 The Sr solution stabilizes the separation column, reducing the corrosion of the separation column by the acidic solution and thus shortening its life.

[0021] Preferably, in step (2), the eluent comprises a Na2EDTA solution and a hydrochloric acid solution, and the flow rate of the eluent into the separation column is 0.1 to 0.5 mL / min.

[0022] Na2EDTA and hydrochloric acid solutions are used as eluents. The Na2EDTA forms a complex with strontium, effectively removing any Sr retained in the separation column. Using hydrochloric acid as the primary eluent prevents the presence of tributyl phosphate in the separation column, which could form a complex with the Na2EDTA and affect column reuse. However, excessively high hydrochloric acid concentrations can damage the column structure and hinder the separation of strontium from its most likely competing ion. Excessively low concentrations can result in poor separation efficiency and make it difficult to separate strontium from competing ions.

[0023] Preferably, in step (2), the volume ratio of the Na2EDTA solution to the hydrochloric acid solution is 1:10-15; the concentration of the Na2EDTA solution is 0.02-0.05 mol / L; and the concentration of the hydrochloric acid solution is 1-2 mol / L.

[0024] Preferably, in step (2), the separated and purified strontium solution is analyzed by mass spectrometry. 87 Sr / 86 The ratio of Sr.

[0025] The strontium isotope ratio of the purified strontium solution is measured using thermal ionization mass spectrometry (TIMS), which can eliminate the interference of other impurity ions and accurately obtain the isotope information of the silk sample.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) Microwave digestion combined with isotope dilution is used to enrich the strontium contained in silk, which reduces the time required to enrich the strontium contained in silk cultural relics and has lower energy consumption; the results are more accurate, which reduces the difficulty of strontium isotope analysis of complex samples such as silk cultural relics;

[0028] (2) Strontium was separated and purified by solid phase extraction. Tributyl phosphate was used as a defoaming agent to reduce the loss of strontium. In addition, tributyl phosphate could form an organic ligand with 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6, forming a certain coordination bond to increase the retention rate of strontium.

[0029] (3) Using Na2EDTA solution and hydrochloric acid solution as eluents can effectively separate the Sr element retained in the separation column; (4) Since the amount of strontium element contained in silk is extremely small, the present invention can eliminate the interference of other impurity ions and effectively enrich and purify the strontium element in silk. In particular, the concentration, volume and flow rate of the solvent used in each step have a positive effect to achieve the best purification effect. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to the embodiments.

[0031] Overall embodiment

[0032] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0033] (1) Strontium isotope enrichment: The silk artifacts were washed with an ethanol-water solution (the volume ratio of ethanol to water was 1-2:1), and then placed in a TFL digestion tank and added 84 Sr diluent, perchloric acid and hydrofluoric acid make silk artifacts, 84 The mass volume ratio of Sr diluent, perchloric acid, and hydrofluoric acid is 1-2 g:0.05-0.1 g:10-15 mL:1-3 mL. The mixture is digested using a microwave digester, and then the mixture is transferred to a clean petri dish and evaporated to near dryness. The dried product is added to a 1-2 mol / L nitric acid solution and centrifuged at 3500-4500 r / min for 10-30 minutes. The supernatant is extracted, and this step is repeated 3-5 times. The supernatant of the last centrifugation is extracted for use.

[0034] (2) Purification of strontium isotopes: Using solid phase extraction, 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 (CAS No.: 28801-57-2) and defoaming agent (tributyl phosphate or n-octanol) were mixed at a mass ratio of 1 to 2:1 and adsorbed on a purification resin separation column (using 50 to 100 μm Amberchrom CG-71md resin, 80-160 μm Amberchrom CG-71cd resin or 100-125 μm Amberlite@XAD-7 resin), use a nitric acid solution with a concentration of 0.01-0.02 mol / L at a flow rate of 0.5-1.0 mL / min to pre-clean the separation column; then use a nitric acid solution with a concentration of 7-10 mol / L as a carrier liquid, and inject the supernatant in step (1) into the separation column at a flow rate of 0.1-0.5 mL / min; then, add 4-6 mL of 84 The Sr solution is injected into the separation column at a flow rate of 0.2 to 0.5 mL / min, and then 7 to 10 mL of an eluent is injected into the separation column at a flow rate of 0.1 to 0.5 mL / min, wherein the eluent is a mixture of a Na2EDTA solution with a concentration of 0.02 to 0.05 mol / L and a hydrochloric acid solution with a concentration of 1 to 2 mol / L in a volume ratio of 1:10 to 15, and finally a separated and purified strontium solution is obtained.

[0035] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0036] Example 1

[0037] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0038] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.05g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 20 minutes. The supernatant was extracted and this step was repeated three times. The supernatant from the final centrifugation was extracted for later use.

[0039] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate were first mixed in a mass ratio of 1:1 and adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 10 mL of 0.01 mol / L nitric acid solution at a flow rate of 0.5 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 0.1 mL / min using 10 mL of 8 mol / L nitric acid solution as the carrier liquid. Then, 4 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.2 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a mixture of a 0.05 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally a separated and purified strontium solution was obtained.

[0040] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0041] Example 2

[0042] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0043] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank and 0.07g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 3500 r / min for 25 min. The supernatant was extracted and this step was repeated four times. The supernatant from the final centrifugation was extracted for later use.

[0044] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate were first mixed in a mass ratio of 1:1 and adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 15 mL of 0.015 mol / L nitric acid solution at a flow rate of 0.5 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 0.3 mL / min using 15 mL of 8 mol / L nitric acid solution as the carrier liquid. Then, 5 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.3 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.3 mL / min. The eluent was a mixture of a 0.05 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally a separated and purified strontium solution was obtained.

[0045] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0046] Example 3

[0047] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0048] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.1g 84 Sr diluent, 15 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 15 minutes. The supernatant was extracted and this step was repeated five times. The supernatant from the final centrifugation was extracted for later use.

[0049] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate were first mixed in a mass ratio of 1:1 and adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 20 mL of 0.02 mol / L nitric acid solution at a flow rate of 1.0 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 0.5 mL / min using 20 mL of 8 mol / L nitric acid solution as the carrier liquid. Then, 6 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.5 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a mixture of a 0.05 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally the separated and purified strontium solution was obtained.

[0050] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0051] Example 4

[0052] The difference from Example 1 is that 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and n-octanol are adsorbed in the purification resin separation column.

[0053] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0054] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.05g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 20 minutes. The supernatant was extracted and this step was repeated three times. The supernatant from the final centrifugation was extracted for later use.

[0055] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and n-octanol were first mixed in a mass ratio of 1:1 and adsorbed on a purification resin separation column of Eichrom Sr (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 10 mL of 0.01 mol / L nitric acid solution at a flow rate of 0.5 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 0.1 mL / min using 10 mL of 8 mol / L nitric acid solution as the carrier liquid. Then, 4 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.2 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a mixture of a 0.05 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally a separated and purified strontium solution was obtained.

[0056] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0057] Comparative Example 1

[0058] The difference from Example 1 is that only the same total mass of 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 is adsorbed in the purification resin separation column.

[0059] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0060] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.05g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 20 minutes. The supernatant was extracted and this step was repeated three times. The supernatant from the final centrifugation was extracted for later use.

[0061] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 was first adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 10 mL of 0.01 mol / L nitric acid solution at a flow rate of 0.5 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 0.1 mL / min using 10 mL of 8 mol / L nitric acid solution as the carrier liquid. Then, 4 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.2 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a mixture of a 0.05 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally a separated and purified strontium solution was obtained.

[0062] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0063] Comparative Example 2

[0064] The difference from Example 1 is that only the same total mass of tributyl phosphate is adsorbed in the purification resin separation column.

[0065] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0066] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.05g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 20 minutes. The supernatant was extracted and this step was repeated three times. The supernatant from the final centrifugation was extracted for later use.

[0067] (2) Purification of strontium isotopes: Using solid phase extraction, tributyl phosphate was first adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 10 mL of 0.01 mol / L nitric acid solution at a flow rate of 0.5 mL / min. Then, 10 mL of 8 mol / L nitric acid solution was used as a carrier liquid. The supernatant in step (1) was injected into the separation column at a flow rate of 0.1 mL / min. Then, 4 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.2 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a mixture of a 0.05 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally a separated and purified strontium solution was obtained.

[0068] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0069] Comparative Example 3

[0070] The difference from Example 1 is that the mass ratio of 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate is 1:2.

[0071] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0072] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.05g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 20 minutes. The supernatant was extracted and this step was repeated three times. The supernatant from the final centrifugation was extracted for later use.

[0073] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate were first mixed at a mass ratio of 1:2 and adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 10 mL of 0.01 mol / L nitric acid solution at a flow rate of 0.5 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 0.1 mL / min using 10 mL of 8 mol / L nitric acid solution as the carrier liquid. Then, 4 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.2 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a mixture of a 0.05 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally a separated and purified strontium solution was obtained.

[0074] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0075] Comparative Example 4

[0076] The difference from Example 1 is that the concentration of the nitric acid solution used as the carrier liquid is 2 mol / L.

[0077] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0078] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.05g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 20 minutes. The supernatant was extracted and this step was repeated three times. The supernatant from the final centrifugation was extracted for later use.

[0079] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate were first mixed in a mass ratio of 1:1 and adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 10 mL of 0.01 mol / L nitric acid solution at a flow rate of 0.5 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 0.1 mL / min using 10 mL of 2 mol / L nitric acid solution as the carrier liquid. Then, 4 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.2 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a mixture of a 0.05 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally a separated and purified strontium solution was obtained.

[0080] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0081] Comparative Example 5

[0082] The difference from Example 1 is that the flow rate of the nitric acid solution as the carrier liquid is 1.0 mL / min.

[0083] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0084] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.05g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 20 minutes. The supernatant was extracted and this step was repeated three times. The supernatant from the final centrifugation was extracted for later use.

[0085] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate were first mixed in a mass ratio of 1:1 and adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 10 mL of 0.01 mol / L nitric acid solution at a flow rate of 0.5 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 1.0 mL / min using 10 mL of 8 mol / L nitric acid solution as the carrier liquid. Then, 4 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.2 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a mixture of a 0.05 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally a separated and purified strontium solution was obtained.

[0086] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0087] Comparative Example 6

[0088] The difference from Example 1 is that the eluent does not contain Na2EDTA solution.

[0089] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0090] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.05g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 20 minutes. The supernatant was extracted and this step was repeated three times. The supernatant from the final centrifugation was extracted for later use.

[0091] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate were first mixed in a mass ratio of 1:1 and adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 10 mL of 0.01 mol / L nitric acid solution at a flow rate of 0.5 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 0.1 mL / min using 10 mL of 8 mol / L nitric acid solution as the carrier liquid. Then, 4 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.2 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a hydrochloric acid solution with a concentration of 2 mol / L, and finally the separated and purified strontium solution was obtained.

[0092] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0093] Comparative Example 7

[0094] The difference from Example 1 is that the concentration of the Na2EDTA solution in the eluent is 0.1 mol / L.

[0095] A purification method for detecting strontium isotopes in silk cultural relics comprises the following steps:

[0096] (1) Strontium isotope enrichment: 1g of silk artifacts was washed with ethanol-water solution (the volume ratio of ethanol to water was 1:1), then placed in a TFL digestion tank, and 0.05g 84 Sr diluent, 10 mL of concentrated perchloric acid, and 2 mL of concentrated hydrofluoric acid were digested using a microwave digester. The mixture was then transferred to a clean petri dish and evaporated to near dryness. The dried product was added to a 1 mol / L nitric acid solution and centrifuged at 4000 rpm for 20 minutes. The supernatant was extracted and this step was repeated three times. The supernatant from the final centrifugation was extracted for later use.

[0097] (2) Purification of strontium isotopes: Solid phase extraction was used. 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate were first mixed in a mass ratio of 1:1 and adsorbed on a purification resin separation column of Amberchrom CG-71md (100 μm) resin. A 2 mL polypropylene tube with an inner diameter of 1 cm and a height of 3.5 cm was used as an extraction chromatographic column. The column contained 0.35 g of resin. The separation column was pre-cleaned with 10 mL of 0.01 mol / L nitric acid solution at a flow rate of 0.5 mL / min. The supernatant in step (1) was then injected into the separation column at a flow rate of 0.1 mL / min using 10 mL of 8 mol / L nitric acid solution as the carrier liquid. Then, 4 mL of 84 The Sr solution was injected into the separation column at a flow rate of 0.2 mL / min, and then 8 mL of the eluent was injected into the separation column at a flow rate of 0.1 mL / min. The eluent was a mixture of a 0.1 mol / L Na2EDTA solution and a 2 mol / L hydrochloric acid solution in a volume ratio of 1:10, and finally the separated and purified strontium solution was obtained.

[0098] (3) Analysis of strontium isotopes: The strontium solution after separation and purification was analyzed by thermal ionization mass spectrometry (TIMS). 87 Sr / 86 The ratio of Sr.

[0099] Table 1

[0100] Example Strontium extraction rate <![CDATA[ 87 Sr / 86 Sr ratio]]> Example 1 98.2％±1％ 0.710728 Example 2 97％±1％ 0.710649 Example 3 96％±1％ 0.711686 Example 4 97％±1％ 0.709871 Comparative Example 1 79±1％ 0.710797 Comparative Example 2 7±1％ 0.710702 Comparative Example 3 56±1％ 0.710754 Comparative Example 4 54±1％ 0.710641 Comparative Example 5 46±1％ 0.710562 Comparative Example 6 85±1％ 0.710856 Comparative Example 7 74±1％ 0.710600

[0101] In Table 1, the extraction rate is calculated as follows: Extraction rate = (A B -A S -A W ) / A B ×100%;A B 、A S 、A W They represent the analyte concentration when the supernatant is injected into the separation column in step (2), the column effluent concentration after the supernatant is injected into the separation column, and the solution concentration after pre-cleaning the separation column.

[0102] As shown in Table 1, the present invention can achieve effective enrichment and purification of strontium in silk, eliminate the interference of other impurity ions, reduce the loss of strontium, and the concentration, volume and flow rate of the solvent used in each step of the purification method all have a positive effect to achieve the best purification effect. It can be seen from Example 4 and Example 1 that after the diluent is replaced by n-octanol, the organic coordination effect formed between it and 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 is weak, and the strontium purification rate is reduced. It can be seen from Comparative Examples 1-3 that the adsorption of 4',4" (5")-di-tert-butyldicyclohexyl-18-crown-6 and tributyl phosphate in the purification resin separation column is particularly important for the effective purification of strontium. Changes in its components and component ratios will affect the organic coordination effect formed with the strontium element, reducing the final strontium extraction rate. From Comparative Examples 4-5, it can be seen that, in the separation process, nitric acid is used as the carrier liquid, and the concentration of the nitric acid solution is too low, it is not possible to effectively remove the separated K + , Ca 2+ Mg 2+ Impurities such as strontium interfere with the ions; and when the nitric acid solution flow rate is too high, bubbles are easily formed in the separation column, both of which are detrimental to achieving optimal purification results. Comparative Examples 6-7 show that the Na2EDTA solution in the eluent can ensure the effective separation of strontium in the separation column, reducing strontium loss. However, excessive concentrations of the Na2EDTA solution will be detrimental to the purification of strontium.

[0103] Unless otherwise specified, the raw materials and equipment used in the present invention are commonly used in the art; the methods used in the present invention are conventional methods in the art unless otherwise specified.

[0104] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A purification method for detecting strontium isotopes in silk cultural relics, characterized in that: The steps include: (1) Strontium isotope enrichment: After cleaning the silk artifacts, add them to the digester for microwave digestion. The digester includes 84 Sr diluent, perchloric acid and hydrofluoric acid, then evaporate to dryness; add the dried product to nitric acid solution and centrifuge to extract the supernatant; (2) Purification of strontium isotopes: First, 4',4''(5'')-di-tert-butyldicyclohexyl-18-crown-6 and defoaming agent were mixed and adsorbed on the purification resin separation column. The defoaming agent was tributyl phosphate. The mass ratio of 4',4''(5'')-di-tert-butyldicyclohexyl-18-crown-6 and defoaming agent was 1~2:

1. The purification resin separation column used was 50~100μm Amberchrom CG-71md resin, 80~160μm Amberchrom CG-71cd resin, 100~125μm Amberlite@ XAD-7 resin or 50~100μm Eichrom Sr Resin, use nitric acid solution to pre-clean the separation column; then use nitric acid solution as a carrier liquid to inject the supernatant in step (1) into the separation column, the concentration of nitric acid solution as a carrier liquid is 7~10mol / L, and the flow rate is 0.1~0.5mL / min; then, 84 The Sr solution and the eluent are injected into the separation column, the eluent includes a Na2EDTA solution and a hydrochloric acid solution, the volume ratio of the Na2EDTA solution to the hydrochloric acid solution is 1:10~15, the concentration of the Na2EDTA solution is 0.02~0.05 mol / L, and the concentration of the hydrochloric acid solution is 1~2 mol / L, to obtain a separated and purified strontium solution.

2. The purification method for strontium isotope detection of silk cultural relics as claimed in claim 1, characterized in that: In step (1), the silk cultural relics are cleaned with an ethanol-water solution; the volume ratio of ethanol to water in the ethanol-water solution is 1-2:

1.

3. The purification method for detecting strontium isotopes of silk cultural relics as claimed in claim 2, characterized in that: In step (1), during the microwave digestion, silk artifacts, 84 The mass volume ratio of Sr diluent, perchloric acid and hydrofluoric acid is 1~2g:0.05~0.1g:10~15mL:1~3mL.

4. The purification method for strontium isotope detection of silk cultural relics as claimed in claim 1, characterized in that: In step (1), the concentration of the nitric acid solution is 1-2 mol / L; the centrifugal separation rate is 3500-4500 r / min, the time is 10-30 min, and the centrifugation is repeated 3-5 times.

5. The purification method for strontium isotope detection of silk cultural relics as claimed in claim 1, characterized in that: In step (2), the concentration of the nitric acid solution during the pre-cleaning is 0.01-0.02 mol / L, and the flow rate is 0.5-1.0 mL / min.

6. The purification method for detecting strontium isotopes in silk cultural relics according to claim 1, characterized in that: In step (2), the purification resin separation column uses 100 μm Amberchrom CG-71md resin or 100 μm Eichrom Sr resin.

7. The purification method for strontium isotope detection of silk cultural relics as claimed in claim 1, characterized in that: In step (2), the 84 The volume of the Sr solution was 4–6 mL, and the flow rate of injection into the separation column was 0.2–0.5 mL / min.

8. The purification method for detecting strontium isotopes in silk cultural relics according to claim 1, characterized in that: In step (2), the flow rate of the eluent injected into the separation column is 0.1-0.5 mL / min.

9. The purification method for detecting strontium isotopes of silk cultural relics according to any one of claims 1 to 8, characterized in that: In step (2), the separated and purified strontium solution is analyzed by mass spectrometry. 87 Sr / 86 The ratio of Sr.