1、Designation: C 1590 04Standard Practice forAlternate Actinide Calibration for Inductively CoupledPlasma-Mass Spectrometry1This standard is issued under the fixed designation C 1590; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he 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 standard practice provides guidance for an alternatelinear calibration for the determination of selec
3、ted actinideisotopes in appropriately prepared aqueous solutions by Induc-tively Coupled Plasma-Mass Spectrometry (ICP-MS). Thisalternate calibration is mass bias adjusted using thorium-232(232Th) and uranium-238 (238U) standards. One of the benefitsof this standard practice is the ability to calibr
4、ate for theanalysis of highly radioactive actinides using calibration stan-dards at much lower specific activities. Environmental labora-tories may find this standard practice useful if facilities are notavailable to handle the highly radioactive standards of theindividual actinides of interest.1.2
5、The instrument response for a series of determinationsof known concentration of232Th and238U defines the massversus response relationship. For each standard concentration,the slope of the line defined by232Th and238U is used to derivelinear calibration curves for each mass of interest usinginterfere
6、nce equations. The mass bias corrected calibrationcurves, although generated from interference equations, arespecific to the instrument operating parameters and tuning ineffect at the time of data acquisition. Because interferenceequations are part of the normal ICP-MS manufacturerssoftware package,
7、 this calibration methodology is widelyapplicable.1.3 For this standard practice, the actinide atomic massrange that has been studied is from amu 232244. Guidance foran extended range of amu 228248 is given in this practice.1.4 Using this practice, analyte concentrations are reportedat each amu and
8、not by element total (that is,239Pu versusplutonium).1.5 This standard does not purport to address all of thesafety concerns, 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 o
9、f regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 859 Terminology Relating to Nuclear MaterialsC 1168 Practice for Preparation and Dissolution of Pluto-nium Materials for AnalysisC 1347 Practice for Preparation and Dissolution of UraniumMaterials for AnalysisC 1411 P
10、ractice for the Ion Exchange Separation of Ura-nium and Plutonium Prior to Isotopic AnalysisC 1414 Practice for the Separation of Americium and Plu-tonium by Ion ExchangeC 1463 Practices for Dissolving Glass Containing Radioac-tive and Mixed Waste for Chemical and RadiochemicalAnalysisD 1193 Specifi
11、cation for Reagent Water3. Terminology3.1 Definitions:3.1.1 For definitions of terms relating to nuclear materials,refer to Terminology C 859.3.1.2 AMUatomic mass unit.4. Summary of Practice4.1 Calibration for the actinides by ICP-MS can be per-formed in a variety of ways with varying degrees of dat
12、aquality. An alternative calibration method has been developedto compensate for instrument mass bias using a generated massresponse curve defined by the232Th and238U data points. Themass response curve defined by232Th and238U approximatesthe mass response curve from amu 232244 as verifiedexperimenta
13、lly and graphically depicted in Fig. 1. The massresponse curve shown reflects the operating parameters andtune of the particular instrument in use at the time of datacollection. Different tuning parameters or instrumentationcould result in varying degrees of negative, neutral, or positivemass bias.
14、Because the mass response curve defined by232Th1This practice is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on TestMethodsPlasma.Current edition approved Jan. 1, 2004. Published January 2004.2For referenced ASTM standards
15、, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at 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 19
16、428-2959, United States.and238U used in this standard practice is determined duringeach calibration, all potential linear variations in mass bias arecompensated for.4.2 The alternative calibration in this standard practicecombines the features of an external linear calibration at eachmass of interes
17、t with the mass bias correction of a mass/response curve. The correction for mass bias is integrated intothe acquisition of the standard data through the use ofinterference equations which, are part of the normal softwarepackage for correction of isobaric interferences in ICP-MSanalyses. Multipoint
18、calibration curves are generated at eachmass of interest, resulting in more accurate quantification thanthat of the typical “semi-quantitative” single point calibrationbased on the mass/response curve alone.4.3 Sample analyses for blanks and samples are performedusing a data acquisition method file
19、without the interferenceequations that were used to derive the calibration curves. Aftercalibration curves are generated, the calibration files are copiedor linked to the analytical acquisition method. The sampleresponses are acquired at each mass, and concentrationscalculated from the mass bias cor
20、rected calibration curves.Some ICP-MS vendor supplied control software will permit thelinking of separate calibration and acquisition files (that is, youcan choose which calibration files to use to quantitate anyparticular data set regardless of the acquisition file that wasused to acquire the data)
21、.4.4 Mixed calibration standard solutions are preparedthrough dilution of single element stock standards of thoriumand known abundance uranium (normally depleted in235U)with dilute nitric acid to develop a calibration series coveringthe desired concentration range. Standard concentrations arecalcula
22、ted for232Th and238U for each calibration solution.4.5 Bismuth-209 (209Bi) is used as an internal standard andis added in a fixed quantity in all standards and samples tocorrect for both instrument drift and physical sample transportfluctuations.5. Significance and Use5.1 One of the benefits of this
23、 standard practice is the abilityto calibrate for the analysis of highly radioactive actinidesusing calibration standards at much lower specific activities(that is,232Th and238U). Environmental laboratories may findthis standard practice useful if facilities are not available tohandle the highly rad
24、ioactive standards of the individualactinides of interest.5.2 The degree of actual mass bias is variable and isdependent upon instrument tune parameters. This standardpractice uses universal interference equations to derive a massbias correction that is specific to the instrument parameters andtune
25、used for sample data acquisition and not based on ahistorical average.5.3 Mass bias correction uses the instrument software inter-ference equations and does not require additional subsequentoff-line calculations.5.4 The methodology that this standard practice is based onhas been used for the determi
26、nation of232Th and237Np inenriched uranium solutions and the determination of241Am inplutonium and uranium legacy oxides following dissolutionand ion extraction chromatography separation.6. Interferences6.1 Isotopes of different elements forming atomic ions withthe same nominal mass-to-charge ratio
27、(m/z) may causeisobaric interferences in ICP-MS if present in sufficient quan-tity (that is,238U with238Pu and241Pu with241Am). Becausethe isotopic abundance of actinides vary widely, it is notpractical to apply an interference correction unless the isotopicabundance of the interference is well char
28、acterized. In addition,the hydride of an abundant isotope can interfere with theadjacent higher mass (that is,238U1Hon239Pu). For thesereasons, it is prudent to implement actinide separation methodsutilizing extraction chromatography resins prior to ICP-MSanalysis to significantly reduce these inter
29、ferences.36.2 Analyte memory can occur when there are large con-centration differences between standards and/or samples thatare analyzed sequentially. Thorium can exhibit memory withinthe sample introduction system. A rinse solution containing0.2M Nitric acid and 0.2M Sulfuric acid has been found to
30、 bebeneficial in reducing thorium carryover.7. Apparatus7.1 ICP-MS, computer controlled with associated softwareand peripherals.7.2 Autosampler, optional, with tube racks, disposable plas-tic sample tubes.7.3 Variable Micro and Macro Pipettes.8. Reagents8.1 Argon (Ar) Gas, high purity $ 99.99 %.8.2
31、Deionized Water, high purity, conforming to Specifica-tion D 1193, Type I.3Maxwell, S. L, “Rapid Actinide-Separation Methods,” Journal of AppliedRadioactivity Measurements, Vol 8, No. 4, 1997, pp. 36-44.FIG. 1 Atomic Mass versus Average Normalized ResponseC15900428.3 Nitric Acid, (specific gravity 1
32、.42), concentrated nitricacid (HNO3), trace metal grade or better.8.4 Sulfuric Acid, (specific gravity 1.84), concentrated sul-furic acid (H2SO4), trace metal grade or better.8.5 Bismuth Stock Solution, (1000 g/mL Bi), matrix nomi-nal 10 % HNO3.8.6 Thorium Stock Solution, (1000 g/mL Th), matrix nomi
33、-nal 2 % HNO3.8.7 Uranium Stock Solution, (1000 g/mL U), matrix nomi-nal 2 % HNO3.8.8 Radioisotope Standards (241Am,242Pu,244Cm, etc.) canbe purchased4to verify calibration curves if laboratory andICP-MS have proper engineering and procedural controls tosafely handle radiological material.9. Hazards
34、9.1 Personnel using this procedure shall be knowledgeableof the safety precautions necessary for normal chemical,radiological handling protocol and instrumental operation ofICP-MS.9.2 Nitric and sulfuric acids are strong oxidizers, avoidcontact with flammable, powdered, or combustible materials.Avoi
35、d contact with skin, eyes and clothing. Do not breathe oringest vapors.9.3 Actinide bearing materials are radioactive and toxic.Adequate laboratory facilities and ventilation hoods along withsafe handling techniques must be used. A detailed discussion ofall safety precautions needed is beyond the sc
36、ope of thisstandard practice. Follow site and facility specific radiationprotection and chemical hygiene protocol.10. Procedure10.1 Calibration Standard PreparationBecause the focusof this practice is on mass bias correction and not on anyparticular calibration concentration range or sample matrix,m
37、inimal instruction is given for the preparation of calibrationstandards.10.1.1 Mixed Calibration Standard solutions are preparedthrough the quantitative dilution of single element bench stockstandards of thorium and known abundance uranium (normallydepleted in235U) with bismuth as an internal standa
38、rd innominal 1 % nitric acid or other acid concentration appropriateto match sample matrix.10.1.2 Calibration Blank consists of the same acid matrixas the standard solutions with the same concentration bismuthinternal standard.10.1.3 Reagent Blank consists of the same acid and chemi-cal matrix as th
39、e samples (if different from the calibrationblank) with the same concentration bismuth internal standard.Consideration should be given to processing the reagent blankthrough any sample prep evolutions such as digestion or ionextraction chromatography separation.10.2 Sample Preparation:10.2.1 Prior t
40、o analysis, digest/dissolve samples as neededusing methods appropriate to the sample matrix such asPractices C 1168, C 1347, C 1463, or other laboratory specificprocedures.10.2.2 Use actinide separation procedures when necessaryto reduce matrix and isobaric interferences between overlap-ping isotope
41、s of interest in the digest solutions; such asPractices C 1411 and C 1414, Maxwells “Rapid Actinide-Separation Methods,”3or other laboratory specific procedures.10.2.3 Dilute sample into appropriate acid matrix (1 to 2 %HNO3typical) with the same concentration internal standard asin the calibration
42、standards. Dilution of samples should beconsistent with the span of calibration standards.10.3 ICP-MS Instrumental Analysis:10.3.1 Set up the ICP-MS for the analysis using the param-eters given in the manufacturers operating manual. Followingplasma initiation, allow the instrument to reach thermal e
43、qui-librium (generally at least 30 min). Optimize the ICP-MS usingroutine tuning protocol for elemental analysis or tune specific4Isotope Products Laboratories, 3017 N. San Fernando Blvd., Burbank, CA91504; (818) 843-7000.TABLE 1 Universal Interference Equations Used to Perform Calibration Mass Bias
44、 CorrectionMass Bias Corrected Calibration Response Calibration Interference EquationCorrected (228) = Response (228) 3 0 (238) 3 0.6667 + (232) 3 1.6667Corrected (229) = Response (229) 3 0 (238) 3 0.5 + (232) 3 1.5Corrected (230) = Response (230) 3 0 (238) 3 0.3333 + (232) 3 1.3333Corrected (231) =
45、 Response (231) 3 0 (238) 3 0.1667 + (232) 3 1.1667Corrected (232) = Response (232) 3 1Corrected (233) = Response (233) 3 0 + (238) 3 0.1667 + (232) 3 0.8333Corrected (234) = Response (234) 3 0 + (238) 3 0.3333 + (232) 3 0.6667Corrected (235) = Response (235) 3 0 + (238) 3 0.5 + (232) 3 0.5Corrected
46、 (236) = Response (236) 3 0 + (238) 3 0.6667 + (232) 3 0.3333Corrected (237) = Response (237) 3 0 + (238) 3 0.8333 + (232) 3 0.1667Corrected (238) = Response (238) 3 1Corrected (239) = Response (239) 3 0 + (238) 3 1.1667 (232) 3 0.1667Corrected (240) = Response (240) 3 0 + (238) 3 1.3333 (232) 3 0.3
47、333Corrected (241) = Response (241) 3 0 + (238) 3 1.5 (232) 3 0.5Corrected (242) = Response (242) 3 0 + (238) 3 1.6667 (232) 3 0.6667Corrected (243) = Response (243) 3 0 + (238) 3 1.8333 (232) 3 0.8333Corrected (244) = Response (244) 3 0 + (238) 3 2 (232) 3 1Corrected (245) = Response (245) 3 0 + (2
48、38) 3 2.1667 (232) 3 1.1667Corrected (246) = Response (246) 3 0 + (238) 3 2.3333 (232) 3 1.3333Corrected (247) = Response (247) 3 0 + (238) 3 2.5 (232) 3 1.5Corrected (248) = Response (248) 3 0 + (238) 3 2.6667 (232) 3 1.6667C1590043to the mass range of interest. Limit oxide formation throughinstrum
49、ent tuning. Oxides are typically monitored using the %ratio of CeO/Ce, usually # 1%.10.4 Actinide Calibration w/Mass Bias Correction:10.4.1 Actinide calibration with mass bias correction isperformed through the use of external linear calibration stan-dards consisting of232Th and238U with209Bi as an internalstandard. Multi-point calibration curves are generated for eachmass of interest between 228 and 248 AMU using theinterference equations in Table 1 to interpolate or extrapolateeach mass response relative to its position on the mass responsecurv
