1、Designation: C1845 16Standard Practice forThe Separation of Lanthanide Elements from UraniumMatrices Using High Pressure Ion Chromatography (HPIC)for Isotopic Analyses by Inductively Coupled Plasma MassSpectrometry (ICP-MS)1This standard is issued under the fixed designation C1845; the number immedi
2、ately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This p
3、ractice provides instructions for the rapid separa-tion of lanthanide elements using high pressure ion chroma-tography (HPIC) from dissolved uranium materials such as:nuclear fuels, uranium ores, hydrolyzed UF6, and depleted,natural, or enriched oxides/powders, or metals. Whenoptimized, this techniq
4、ue will produce purified elementalfractions of the lanthanide elements isolated from the bulkuranium matrix allowing for isotopic assay using inductivelycoupled plasma mass spectrometry (ICP-MS).1.2 This practice is most applicable for analyte concentra-tions of nanograms per gram uranium or higher.
5、 For ICP-MSdetection and measurement of analyte concentrations lowerthan this, it would be necessary to perform additional pre-cleanup or concentration techniques, or both, which are notaddressed in this practice.1.3 When combined with isotope dilution, this practice canalso be used for improved pre
6、cision assays of the lanthanideelements using the principle of isotope dilution mass spectrom-etry (IDMS).1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thispractice.1.5 This standard does not purport to address all of thesafety concern
7、s, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C859 Terminology Relating to Nuclear Mater
8、ialsC1052 Practice for Bulk Sampling of Liquid UraniumHexafluorideC1075 Practices for Sampling Uranium-Ore ConcentrateC1168 Practice for Preparation and Dissolution of PlutoniumMaterials for AnalysisC1347 Practice for Preparation and Dissolution of UraniumMaterials for AnalysisC1689 Practice for Sub
9、sampling of Uranium HexafluorideC1769 Practice for Analysis of Spent Nuclear Fuel to De-termine Selected Isotopes and Estimate Fuel BurnupD1193 Specification for Reagent WaterE105 Practice for Probability Sampling of Materials3. Terminology3.1 DefinitionsFor definitions of terms used in thispractice
10、, refer to Terminology C859.4. Summary of Practice4.1 Solid samples are dissolved according to PracticesC1168, C1347, or other appropriate methods. Uraniumhexafluoride can be sampled in accordance with PracticesC1052 and C1689. The resulting dissolver solution is pro-cessed to produce solutions of i
11、solated lanthanide elements formass spectrometric isotopic analysis. The elements are selec-tively separated from the dissolver solution and collected usingHPIC instrumentation equipped with automated fraction col-lection. Appropriate aliquots of the unseparated dissolutions1This practice is under t
12、he jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved June 1, 2016. Published June 2016. DOI: 10.1520/C1845-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM
13、Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1are taken to provide up to 100 n
14、g/mL of a lanthanide elementon the analytical column to be separated from 3.5 mg/mL orless of uranium. In a strong nitric acid matrix, no pre-separation valence adjustments are necessary.NOTE 1This practice has been verified to separate 0.7 mg of totaluranium from the lanthanide analytes. 20 ng tota
15、l of each analyte has beenshown to have efficient resolution on the column to yield purifiedelemental samples. If larger uranium and analytes sample sizes are beingconsidered, it is suggested that these be verified by the lab for efficienturanium removal and analyte resolution.4.2 For the separation
16、 HPIC sample aliquots are injectedusing a 200 L sample loop and loaded ontoa4by250mmhigh pressure cation exchange column with sulfonic acidfunctional groups and an ion exchange capacity of 80micro-equivalents/columns. First, complexation and removalof the bulk dissolved uranium matrix is accomplishe
17、d using adilute hydrochloric acid eluent which is directed to waste.Next, the lanthanide elements are selectively eluted off of thecolumn by chelation chromatography using a dilute solution of2-hydroxyisobutyric acid (-HIBA). Fractions are collected atautomated 20 s time intervals to allow for recov
18、ery of theseparated analytes, producing purified aliquots of each lan-thanide element from the bulk uranium matrix of the dissolversolution for isotopic measurements using ICP-MS.5. Significance and Use5.1 The measurement of isotopic distributions for the lan-thanide series elements is of important
19、to all phases of thenuclear fuels cycle. Examples include the purification of theNd isotopes from Ce and Sm isotopes for the determination ofatom percent fission through the production of148Nd inirradiated nuclear fuels using Practice C1769, determination ofrare earth content and isotopic distributi
20、on in Uranium OreConcentrates (UOC) for source term and production of lan-thanide fission products in irradiated nuclear fuels for determi-nation of performance, improvements of depletion codes, andanalysis of burnup indicators.36. Interferences6.1 High salt content in the sample can potentially inf
21、luenceboth the retention times and the resolution of the analytes. Theconcentration of the nitric acid in the sample matrix does notnecessarily influence the retention times and the resolution ofthe analytes, but it can influence the removal of uranium. 2 Mnitric acid has been successful in efficien
22、tly removing uranium.6.2 The presence of high concentrations of sulfate,phosphate, oxalate, and halides in the sample matrix willpotentially have an effect on the retention times and theresolution of the analytes.NOTE 2Using a smaller sample injection loop volume with a higheranalyte concentration c
23、an reduce the effects of the matrix on the retentiontimes and the resolution of the analytes.6.3 Temperature can impact the retention times and theresolution of the analytes and, where possible, a thermalcompartment should be employed to maintain consistencybetween sample analyses.7. Apparatus7.1 Hi
24、gh pressure ion chromatograph equipped with asingle variable speed gradient pump capable of delivering flowrates of 0.001 to 10 mL/min. The system requires eluent degascapability and a low pressure gradient mixer capable of mixingfour independent eluent streams.7.1.1 Optionally the HPIC may be equip
25、ped with a post-column reaction coil using a chromophore for detection via asingle or multi-wavelength UV/Vis absorption detector tomeasure the appropriate wavelength emission.7.1.2 Using an integrated online detector is useful for initialinstrument testing and setup of the parameters for the lan-th
26、anide separations and determining initial time intervals forthe collection of fractions.Also, with the detector online duringfraction collection it could be used as a trigger for the fractioncollector. CAUTION: The nature of the post-column chro-mophore solution may have an impact in post separation
27、analyses.7.2 Autosampler for sample injection equipped with a 10-port injections switching valve is recommended. Alternately, amanual injection setup can be used.7.3 Sample loop. A 200 L sample loop is considered to beoptimal for this practice; however, injection loops can varyfrom 25 to 1000 L depe
28、nding on sample concentrations.NOTE 3Matrix effects with regard to peak resolution must beconsidered when choosing large sample loop volumes.7.4 Analytical column. Standard bore high pressure analyti-cal column (2504mmI.D.) with sulfonic acid functionalgroups and an ion exchange capacity of 80 micro
29、-equivalents/columns. Standard bore is required over micro bore columns tosupport greater resolution for complex sample matrices.7.5 Guard column. Standard bore guard column (504mmI.D.) is required to protect the analytical column from samplecontaminates which will degrade the performance of thecolu
30、mn.7.6 Fraction collector. Automated fraction collector eitheras a standalone system that communicates with the HPIC unitor integrated into the instrument.8. Reagents and Materials8.1 Purity of ReagentsHigh purity grade acids and reagentgrade chemicals shall be used for the preparation of eluentstoc
31、k solutions. High concentrations of ionic impurities ineluents will degrade column performance over time andadversely affect the separation chemistry resulting in inconsis-tent retention times or unacceptable overlaps, or both, betweenthe rare earth elemental fractions. It is intended that all acids
32、and reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.8.2 Purity of WaterType II Reagent Grade Water with aspecific resistance of 18.2 M-cm, according to SpecificationD1193, shall be used in the prepa
33、ration of all high purity acids,reagents, and eluents.3Re-evaluation of Spent Nuclear Fuel Assay Data for the Three Mile Island Unit1 Reactor and Application to Code Validation, Annals of Nuclear Energy, Vol 87,Part 2, January 2016, pp. 267281.C1845 1628.3 Nitric Acid (HNO3), concentrated, 1.42 g/mL
34、 70 %(mm).8.4 Nitric Acid (HNO3), 2.0 MDilute 125 mL concen-trated HNO3to a final volume of 1000 mL with water.8.5 Hydrochloric Acid (HCl), concentrated, 1.18 g/mL,36 % (m/m).8.6 Hydrochloric Acid (HCl), 1.0 MDilute 100 mL con-centrated HCl to a final volume of 1000 mL with water.8.7 Ammonium Hydrox
35、ide, 28 % NH3in H2O, 99.99 %purity.8.8 -Hydroxyisobutyric acid (-HIBA), 0.4 M, reagentgrade, 99 %Dissolve 41.6 g -HIBA in 500 mL water (8.2),buffer to a pH of 4.5 with Ammonium Hydroxide, approxi-mately 18 mL, and bring to a final volume of 1000 mL.9. Hazards9.1 Strong acids are used for the prepara
36、tion of reagents.Wear appropriate personal protective equipment while han-dling nitric and hydrochloric acids. Lab coat, gloves, and safetyglasses with side shields are considered to be the minimumrequirement. When handling large volumes of acid, a full faceshield should be used.9.2 Hydrochloric aci
37、d (HCl) vapors are very corrosive. Alldilutions of HCl solutions should be made in a fume hood toavoid inhalation of vapors.9.3 Ammonium hydroxide is corrosive. Wear appropriatepersonal protective equipment when handling and performwork within a chemical fume hood to avoid inhalation ofvapors.10. Sa
38、mpling, Test Specimens, and Test Units10.1 Sampling of UOC in a processing environment isperformed according to Practices C1075 and liquid uraniumhexafluoride by Practice C1052. All others should followPractice E105.10.2 Test specimens are obtained through acid dissolutionaccording to Practices C134
39、7, C1168, or other appropriatemethods. The dissolution of uranium-plutonium mixed oxidesis covered in Practice C1168.NOTE 4Many uranium-containing materials such as high-puritymetals and oxides dissolve readily in various inorganic acids. Nitric aciddissolutions are preferred for this practice; howe
40、ver, small quantities ofHCl, HF, or H2SO4will not affect the HPIC separation.NOTE 5Samples prepared using fusion techniques have not beentested.10.3 Preparation of Dissolved Samples and Blanks:10.3.1 Using 2 M HNO3dilute an appropriate aliquot ofeach sample such that the total uranium concentration
41、is 3.5mg/mL or less and to provide up to 100 ng/mL of a lanthanideelement to be loaded onto the analytical column.10.3.2 Subsamplea1mLaliquot of each dilution into a 5mL vial (preferentially made out of a perfluoroalkoxy (PFA)material).10.3.3 Fume the aliquots to dryness on a hotplate at amedium hea
42、t.10.3.4 Once dry, add 0.5 mL of2MHNO3and repeat thedry down process.10.3.5 Add 1 mL of 2 M HNO3to the hot vial, cap, andallow the sample to cool.NOTE 6Preferably perform the dry down steps in a trace cleanenvironment or in a HEPA-filtered enclosure to minimize external sourcesof elemental contamina
43、tion.10.3.6 Transfer the sample to the appropriate autosamplervial and label accordingly.10.4 Blanks:10.4.1 Prepare method blanks that were taken through thedissolution protocol with the samples by following steps 10.3.1through 10.3.6 above.10.4.2 Prepare instrument blanks by adding 1 mL of 2 MHNO3t
44、o the appropriate autosampler vial and label.11. Preparation of Apparatus11.1 After extended use or noticeable degradation of col-umn performance, or both, the guard and analytical columnsshall be cleaned. It is recommended that they be cleanedseparately following the manufacturers recommendation so
45、that contaminants on the guard column do not elute onto theanalytical column.NOTE 7If the column is unused for any significant length of time lowmolarity HCl (1050 mM) is a suitable storage solution that does notrequire changing any of the eluents. For long term storage, follow thecolumn manufacture
46、rs instructions.11.2 If the columns are to be used after long-term storage,prepare them for use following manufacturers instructions.11.3 Minimize void volumes in the sample flow path permanufacturers recommendations and ensure that all tubingconnections are tightened to manufacturers recommendation
47、sand are leak free.11.4 Configure the instrument with a 200 L sample loopfor optimum sample loading and a flow rate of 1.0 mL/min.NOTE 8For optimum separation performance refer for manufacturersmanual for ideal column pressure and adjust the eluent flow rateaccordingly.11.5 Verify that all modules o
48、f the HPIC system are activeand respond to the control computer per manufacturers in-structions.11.6 Program the gradient pumping profile into the instru-ment control software as shown in Table 1.11.7 Check that there are adequate volumes for the eluentslisted in Table 1.NOTE 9Shelf-life of the 0.4
49、M -HIBA eluent is 14 days. Properbuffering of the solution to a pH of 4.5 is important to separationperformance.TABLE 1 Gradient ProfileTime (min) DI Water (%) 1M HCl (%) 0.4 M HIBA (%)0.00 0 100 00.10 90 0 108.00 90 0 1028.00 35 0 6535.00 0 0 0C1845 16311.8 Prime the system pump heads, autosampler syringe andsample injection loop following the manufacturers instruc-tions.11.9 Pre-rinse the analytical and guard columns by pumpingthe system with 1 M HCl for 5 min followed by 0.01 M HClfor 5 min.11.10 Follow the first pre-rinse of the c
