1、Designation: C 1614 05Standard Practice for theDetermination of237Np,232Th,235U and238U in Urine byInductively Coupled Plasma-Mass Spectrometry (ICP-MS)and Gamma Ray Spectrometry1.This standard is issued under the fixed designation C 1614; the number immediately following the designation indicates t
2、he 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the separation and preconce
3、ntrationof neptunium-237 (237Np), thorium-232 (232Th), uranium-235(235U) and uranium-238 (238U) from urine followed by quan-titation using ICP-MS.1.2 This practice can be used to support routine bioassayprograms. The minimum detectable concentrations (MDC) forthis method, taking the preconcentration
4、 factor into account,are approximately 1E-2Bq for237Np (0.38ng), 2E-6Bq for232Th(0.50ng), 4E-5Bq for235U (0.50ng) and 6E-6Bq for238U(0.48ng).1.3 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is theresponsibility of the user of this standard
5、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:2D 1193 Specification for Reagent Water.C 1475 Standard Guide for Determination of Neptunium-237 in Soil.C 859 Standard Terminology
6、Relating to Nuclear Materials.C 1379 Standard Test Method for Analysis of Urine forUranium-235 and Uranium-238 Isotopes by InductivelyCoupled Plasma-Mass Spectrometry.D 4962 Standard Practice for NaI(Tl) Gamma-Ray Spec-trometry of Water3. Terminology3.1 Definitions not found in C 859 Standard Termin
7、ologyRelating to Nuclear Materials:3.1.1 Instrument check standardstandard solutions evalu-ated at specified intervals during batch analysis to evaluateinstrument calibration stability during analysis.3.1.2 Internal standardsolutions added to each calibrationstandard, check standard, and sample for
8、the purpose ofmonitoring and correcting for instrument drift, due to aerosoltransport effects, nebulizer blockage, ion sampling orificeblockage and matrix enhancement or suppression.3.1.3 Isobarany nuclide that has the same atomic massnumber as another nuclide, but a different atomic number3.1.4 Iso
9、tope dilution analysisisotope ratio measurementsof samples spiked with accurately known weights of individuallow abundance isotopes3.2 Acronyms:ICP-MS = Inductively Coupled Plasma-Mass SpectrometryPHA = Pulse Height AnalysisLOD = limit of detectionMDC = minimum detectable concentrationLCS = laborato
10、ry control standard4. Summary of Practice4.1 An aliquot of a urine sample is spiked with239Np,230Thand233U tracers followed by wet ashing with nitric acid andhydrogen peroxide. After re-dissolution in nitric acid contain-ing aluminum nitrate and sodium nitrite, the analytes areextracted using an ext
11、raction chromatography resin. For analy-sis by ICP-MS the eluent is spiked with242Pu internal standardfollowed by wet ashing with nitric acid and re-dissolution in 5mL 5 % nitric acid4.2232Th,235U and238U are determined using ICP-MS iso-topic dilution techniques. Chemical yield (recovery) measure-me
12、nts indicate a typical yield of 75-85 % for these analytes.The isotopic composition of uranium is determined by ICP-MSisotopic ratio measurements.237Np is determined by ICP-MSusing external standardization combined with239Np recoverymeasurements (85-95 %) using gamma-ray spectrometry.1This practice
13、is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the responsibility of Subcommittee C 26.05 on Methods of Test.Current edition approved June 1, 2005. Published June 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service a
14、t serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 This practice may be u
15、sed as part of a bioassay programfor workers potentially exposed to nuclear material bymeasuring237Np,232Th and235U and238U in their urine samples.ICP-MS has been used to analyze for many actinides inhigh-level radioactive wastes (1)3, in soils (2) as well asuranium in urine (C 1379).237Np and239Pu
16、analysis by ICP-MSin bioassay samples has also been reported (3).5.2 Several days counting times are required for alpha-particle analysis of237Np,232Th and235U and238U whereasICP-MS requires only four minutes per sample. Alpha-particlecounting methods for neptunium may also require the useof239Pu as
17、 a radiotracer for determination of chemical yield.5.3 ICP-MS sensitivity limits and isobaric interferencespreclude accurate determination of239Pu,241Am and234Uatlevels present in the urine samples.234U may be estimated fromthe235U:238U ratio by inference.6. Interferences6.1 ICP-MS6.1.1 Alkali and a
18、lkaline earth salts in urine result in signalattenuation. However, in this practice neptunium, thorium anduranium are chemically separated from the salts using anextraction chromatography resin.6.2 If243Am is added as a source of239Np, the chemical yielddetermination could be biased by the presence
19、of239Np grow-ing in from the243Am parent. The243Am should be selectivelyeluted from the extraction chromatography column prior toelution of the analytes.7. Apparatus7.1 ICP-MS, computer-controlled, equipped with a discretedynode electron multiplier and auto-sampler.7.2 Gamma-ray spectrometry system,
20、 see D 4962 for furtherinformation.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society where
21、such specifications are available4.8.2 Purity of waterunless otherwise noted ASTM Type Iis used to prepare all solutions for ICP-MS analysis (D 1193).8.3 High purity concentrated nitric acid (HNO3), (approx.16M).8.4 Hydrogen Peroxide, (30 %).8.5 Nitric Acid (2M)Add 125 mL of concentrated HNO3to 700
22、mL of water, dilute to a final volume of 1000 mL, andmix.8.6 Nitric AcidAdd 50mL of concentrated HNO3to 700mL of water, dilute to a final volume of 1000 mL, and mix.8.7 0.5 M Aluminum Nitrate Solution, (Al(NO3)3.9H2O)dissolve 187.5g of pure aluminum nitrate in 2M nitric acid anddilute to 1L with 2M
23、nitric acid.8.8 Sodium Nitrite, (NaNO2).8.9 0.1 M Ammonium Bioxalate, (NH4HC2O4)dissolve6.31g of oxalic acid dihydrate and 7.11g of ammonium oxalatemonohydrate in water and dilute to 1L.8.10 Disposable columns packed with 0.7g extraction chro-matography resin5.8.11 Argon Gaspurity 99.99 % or better.
24、8.12 Standard Metals Stock Solutiona solution of beryl-lium, cobalt, indium, lead, and uranium, which covers the massrange that is used for tuning, detector and mass calibration andas an instrument stability check following the instrumentmanufacturers recommendations.8.13 Calibration Stock Solution
25、containing237Np6in 5 %HNO3.8.14242Pu Internal Standard Solution7.8.15230Th Tracer7solution.8.16233U Tracer8solution.8.17239Np tracer, available as243Am daughter7, (see 6.2).9. Solutions9.1 Prior to the ICP-MS analysis of the samplesfor237Np,232Th and235U and238U, the following QC standards,calibrati
26、on standards, internal standard, and rinse solutionshould be prepared and included in the analytical run.9.1.1 Rinse SolutionAdd 2 part volume high purity con-centrated HNO3per 100 parts water. Prepare a sufficientquantity to flush the ICP-MS and autosampler between stan-dards and samples.9.1.2237Np
27、 calibration standardscalibration standardsshould be prepared in 5 % HNO3by diluting the calibrationstock solution.9.1.3 Calibration blank5 % HNO3.9.1.4237Np instrument check standardPrepare in 5 %HNO3. Analyze a mid-range standard (e.g. 5ng/mL) through-out the batch analysis at a minimum frequency
28、of 10 %.9.1.5 Isotope dilution standards239Np,230Th and233Uataconcentration deemed appropriate for the laboratory program.9.1.6 Unexposed urine, spiked with237Np,239Np,230Thand233U to demonstrate the ability to quantitatively recover theradionuclides of interest.9.1.7242Pu internal standard for spik
29、ing into each blank,standard and sample.10. Sampling, Test Specimens10.1 Collect urine samples from individuals and store untilanalysis. Preservatives may be used if deemed necessary toensure stability.10.2 All chain of custody requirements described inlaboratory-specific operating procedures must b
30、e followed.3The boldface numbers in parentheses refer to the list of references at the end ofthis practice.4Available from American Chemical Society, 1155 Sixteenth Street, NW,Washington DC, 20036, Phone: 202-872-4600, Fax: 202-872-4615, Website:http:/www.chemistry.org.5TRU Resin, available from Eic
31、hrom Technologies, Inc., Darien, IL has beenfound suitable for this purpose.6Available from Isotope Products Lab, Burbank, CA or equivalent.7Available from NIST, Gaithersburg, MD or equivalent.8Available from New Brunswick Lab, Argonne, IL, or equivalent.C161405211. Calibration and Standardization11
32、.1 Follow the instrument manufacturers operatingmanual and laboratory-specific operating procedures for initialstart-up and optimization of the ICP-MS and the associatedcomputer control system and peripheral equipment11.2 Set up the necessary instrument software files for dataacquisition, calculatio
33、n, quality assurance and quality controldata requirements, archival data storage, analytical reportpreparation, and report verification.11.3 The instrument, data acquisition, and reporting param-eters shall be determined to meet customer statement of workrequirements.11.4 Introduce the recommended t
34、uning solution and tunethe instrument for optimum response for238U.11.5 Check the mass calibration and resolution with thedaily tuning solution and elements recommended as per themanufacturers instrument specifications.11.6 Make necessary adjustments in the instrument controlsto ensure that all of t
35、he above operating parameters (masscalibration, mass resolution, resolution, and baseline) arewithin previously established laboratory limits. Use the appro-priate concentrations for each of the calibration functionssuggested by the instrument manufacturer.11.7 Determine the instrument stability bef
36、ore analyzingany samples. The stability is determined by analyzing five 60second replicates of the daily tuning solution to meet a relativestandard deviation of less than 2 % for59Co,115In,208Pband238U isotopes.11.8 If the relative standard deviation for these isotopesduring instrument stability tes
37、ting is greater than 2 %, deter-mine the cause of the instability, correct the problem, and rerunthe stability check.11.9 Calibrate for237Np to cover the required analyticalrange, e.g. 0-10ng/mL. No calibration is required for thoriumand uranium since isotopic dilution is used to determine theconcen
38、tration.12. Procedure12.1 Sample Preparation12.1.1 Add known amounts of239Np,230Th and233Uto250mL urine before wet-ashing with a mixture of 15mL highpurity concentrated HNO3and 1mL 30 % H2O2followed byslowly evaporating the sample to dryness.12.1.2 Allow to cool and redissolve the sample residue aft
39、erwet ashing in 10-20mL aluminum nitrate solution (8.7).12.1.3 Add sufficient sodium nitrite (8.8) to each sampleadjust the oxidation state of Np to Np(IV).12.1.4 Load the sample onto the disposable extractionchromatography resin column and wash with at least 20mL of2 M HNO3before eluting the isotop
40、es of interest with 20mLammonium bioxalate solution (8.9).12.1.5 Spike each sample with a known quantity of242Pubefore drying and wet-ashing to remove the bioxalate.12.1.6 Redissolve the sample residue after ashing in 5 mL5 % HNO3before analysis by gamma-ray spectrometry(239Np) and ICP-MS. This solu
41、tion results in a 503 precon-centration from the original sample.12.2 Gamma-ray spectrometry of239Np12.2.1239Np gamma rays are counted using a gamma-rayspectrometer as described in C 1475.12.3 ICP-MS Analysis of232Th,237Np,235U and238U12.3.1 Ensure that all instrument set-up, calibration andstandard
42、ization (see Section 11), and required laboratory-specific QC protocol has been followed.12.3.2 To ensure that the ICP-MS provides requisite sensi-tivity, 3-sigma detection limits for each of the isotopes maydetermined by collecting a series of five individual acquisitionsof one-minute duration.12.3
43、.3 Analyze the standards, prepared samples, and pre-pared LCS following the ICP-MS and data systems operationsdescribed in the site-specific laboratory operating procedures.13. Calculation of Results13.1 Determine the chemical recovery fraction for eachsample and control from the following equation
44、for each tracer:Chemical recovery 5concentration of tracer measured!concentration of tracer added!3 100 %(1)13.2 Gamma-ray analysis of239Np13.2.1239Np chemical recovery is calculated from thegamma-ray counts as described in C 1475. Chemical recover-ies are typically between 85 95 %.13.3 ICP-MS Analy
45、sis of237Np13.3.1237Np concentration is calculated from a237Np cali-bration curve with242Pu being used as an internal standard.13.3.2 The true237Np concentration (measured by ICP-MS)is corrected by239Np chemical recovery (measured by gamma-ray).13.3.3 Determine the final Np-237 result according to t
46、hefollowing equation:3Final Result 5 T/Chemical Recovery (2)Where T = measured ICP-MS concentration in the sample(ng/mL).13.4 ICP-MS Analysis of232Th and235U and238U13.4.1 The ICP-MS data should include the followingratios:230/232Th,235/233U,238/233U,235/238U, and the followingconcentrations:230Th (
47、based on the230Th/242Pu internalstandard),233U,237Np. The230/232Th,235/233U,238/233U,235/238Uratios are used to determine the232Th,235U,238U concentrations.The230Th and233U concentrations may be used to determinechemical yield. Chemical recoveries are between 75 85 %.13.4.2232Th and235U and238U conc
48、entrations are calculatedby isotope dilution from the isotope ratio measurementsof232Th/230Th,235U/233U and238U/233U. Human urine shouldnot contain any233U (or230Th) , therefore isotope dilutionformula for238U is:M 5 nRM2 RS!M (3)where M is the total mass of238U in the sample (pg), n is thenumber of
49、 moles of233U (pmol) in the added spike, RMand RSare the molar ratios238U/233U in the resulting mixture andadded spike, respectively, and M is the molar mass of theisotope238U (pg pmol-1). The same calculation can be appliedto232Th and235U using230Th and233U respectively (4).C161405313.4.3235U and238U isotopic ratios may also be determined(Table X1.1).14. Precision and Bias14.1 Data for each sample was obtained from four one-minute scanning acquisitions between m/z 229 to m/z 243.Each one-minute acquisition consisted of data summed from1000 sweeps of the qua
