1、Designation: C1844 16Standard Test Method forDetermination of Uranium in Urine by Inductively CoupledPlasma Mass Spectrometer Following Nitric Acid Dilution1This standard is issued under the fixed designation C1844; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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 test method covers the determination of uranium inurine by Inductive
3、ly Coupled Plasma Mass Spectrometry(ICP-MS) after dilution in nitric acid. The method is presentedin two parts. Part A describes a method for determination oftotal uranium in urine that does not distinguish betweenuranium isotopes. Part B describes a method that determinesthe ratio of235Uto238U (the
4、 enrichment) in samples that PartA has shown to contain levels of uranium that the user of thedata considers to be significant. The measurement in Part Bmay be combined with the measurement in Part A to calculatea235U concentration. The enrichment measurement may inturn be used to estimate levels of
5、 minor uranium isotopes, inparticular234U, that are important for calculating the internalradiation dose received by an individual exposed to uranium.The estimation of minor isotope concentrations and the calcu-lation of internal dose does not form part of this standard.1.2 UnitsThe values stated in
6、 SI units are to be regardedas standard. No other units of measurement are included in thisstandard.1.3 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 heal
7、th practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C859 Terminology Relating to Nuclear MaterialsD1193 Specification for Reagent Water3. Terminology3.1 DefinitionsFor definitions of other standard terms inthis test method,
8、refer to Terminology C859.3.2 Definitions of Terms Specific to This Standard:3.2.1 internal reference standarda solution containingnon-analyte elements that is analyzed by the ICP-MS alongsideall samples. The signal is used to correct for small matrixeffects and instrumental drift during the run to
9、give a moreprecise measurement. The element or elements are selectedsuch that they are not present in the unknown samples atsignificant concentrations, are within the general mass range ofthe measured analytes and have similar chemical behaviors inthe instrument.3.2.2 method blanka solution which in
10、 so far as ispractical duplicates the preparation process of the sample to beanalyzed and passes through the same measurement processbut does not initially contain significant quantities of any of theanalytes to be measured.3.2.2.1 DiscussionThe method blank does not initiallycontain significant qua
11、ntities of analyte, hence the value of anyanalyte measured may be assumed to be due to interference,matrix effects or contamination introduced as a consequence ofsample processing. If the contribution of such factors isevaluated to be representative to the measurement of theunknown samples in the ba
12、tch then subtracting the measuredvalue for the method blank from the value measured on thegenuine sample will eliminate these interferences, typicallyproviding a better estimate for the true value of the quantity ofanalyte in the sample.3.2.3 spikea known quantity of analyte added to a samplewhich i
13、s used to evaluate losses during the sample preparationprocess or biases during measurement.4. Summary of Test Method4.1 For the determination of total uranium in urine: samplesof urine are initially diluted by a factor of 20 with 0.32 M nitricacid (this is a 2 % by volume dilution of typical, conce
14、ntratednitric acid). The diluted sample is then analyzed for totaluranium using an ICP-MS. Prior to analysis of samples theinstrument is calibrated using 0, 50, 100, and 200 ng/LUranium Standards prepared in 0.32 M nitric acid, that hasbeen prepared using ultra high purity (UHP) concentrated acid.Th
15、e Certified Reference Materials used for Standard prepara-tion typically contain natural uranium. A method blank is runafter the calibration and all subsequent results are blank1This test method is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of
16、Subcommittee C26.05 on Methods ofTest.Current edition approved Dec. 15, 2016. Published December 2016. DOI:10.1520/C1844-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, r
17、efer 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization establ
18、ished in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organiziation Technical Barriers to Trade (TBT) Committee.1corrected. A 50 ng/L Uranium Instrument Quality ControlSample is also analyzed after the calibration in o
19、rder tomaintain quality control of the instrument. An on-line internalreference standard of 2 g/L thorium is analyzed with everysample in order to correct results for minor matrix effects andinstrumental variation between samples, in particular for in-strumental drift.4.2 For the determination of th
20、e235Uto238U ratio in urine:samples that have been shown to contain levels of uranium thatare sufficiently high to allow enrichment to be determined andthat the user of the data considers to be significant are dilutedby a factor of 5 with 0.32 M nitric acid, UHP. The235Uto238Uratio in the diluted sam
21、ple is measured on an ICP-MS whichhas been calibrated for mass bias parameter using a 200 ng/Lsolution of a uranium reference material with certified enrich-ment level. A 200 ng/L Uranium Instrument Quality ControlSample is analyzed after the calibration in order to maintainquality control of the in
22、strument. At the end of the measure-ment run a method quality control sample in a urine matrix isalso measured.4.3 The concentration of235U may be calculated using theresults from the two determinations.NOTE 1A lower dilution factor than the 20 used for total uraniummeasurement may be used for the d
23、etermination of the235Uto238U ratioas any interference from the matrix should affect each isotope equally.5. Significance and Use5.1 It is common practice within the nuclear industry forinternal dose assessment to be made as part of a bioassayprogram for nuclear facility workers. For indirect bioass
24、ay ofworkers that may be exposed to uranium at enrichments thatmay differ from natural then the235U concentration must bemeasured in addition to the total uranium isotopes so that anestimate of uranium enrichment may be made for use in thedose assessment.5.2 The enrichment measurement may also be of
25、 value intracing the source of uranium exposure should significanturanium levels be detected in a sample.5.3 A modern, quadrupole ICPMS should be capable ofdelivering performance characteristics close to those claimedin this test method; however, older models or those whereperformance has deteriorat
26、ed over time may be unable to do so.It is the responsibility of the user to validate the performanceof their equipment.6. Interferences6.1 No isobaric elemental interferences have been identifiedwhen employing this method in uranium processing facilities;however, interferences can be envisaged for f
27、acilities alsoprocessing transuranic elements such as plutonium. In suchinstances, the facility will need to determine whether thequantity present could result in interference that is significant.6.2 It is possible that significant quantities of minor uraniumisotopes, such as234U and236U could resul
28、t in a bias on the235Uto238U ratio measured in part B. The ratio of234U and236Uto235U is low for unirradiated uranium at all enrichmentsand will make no significant contribution to the235U measure-ment. The ratio may be significantly higher for reprocesseduranium; however, even in this case any bias
29、 is likely to be lessthan 10 % of the235U value. A highly enriched uraniumreference material (NBS 930, 93.28 % mass235U, 1.08 % mass234U) was measured repeatedly during the validation of themethod and the results for the235U enrichment level agreedwith the certified value to well within the uncertai
30、nty for themethod.PART A DETERMINATION OF TOTAL URANIUMIN URINE7. Apparatus7.1 Equipment materials must be compatible with nitricacid. Each type of container should be tested to ensure that itdoes not contain leachable uranium that might affect themeasurement by soaking in dilute nitric acid and mea
31、suring theuranium content of the acid after leaching.7.2 Required apparatus is:7.2.1 ICP-MS controlled by computer and fitted with asso-ciated software and peripherals. A compatible autosampler ishighly recommended.7.2.2 Pipets, variable volume, in appropriate sizes such as 1to 10 mL; 100 to 1200 L;
32、 20 to 300 L; 5 to 100 L used withpolyethylene pipette tips.7.2.3 Volumetric flask, 100 mL.7.2.4 Graduated cylinder, 100 mL or 250 mL.7.2.5 Sample bottles, 125mL,1L,2L.7.2.6 Aspirator bottle, 10 L.7.2.7 Screw cap sample tubes, 50 mL (polypropylene cen-trifuge tubes have been found to be suitable).7.
33、2.8 Plastic Pasteur Pipets, 1 mL.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society
34、,where such specifications are available.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean laboratory accepteddemineralized or deionized water in conformance with Speci-fication D1193, Type 1.8.3 UHP concentrated nitric acid (HNO3), density 1.42g/mL, (16 M
35、, 70 % mass).8.4 Dilute nitric acid, 0.32 M, UHP (a 2 % by volumedilution of the acid listed in 8.3). Add approximately 9 L ofwater to a 10 L Aspirator Bottle. Add 200 mL of concentratednitric acid, UHP to the aspirator bottle using a graduatedcylinder and dilute to 10 L with water. Mix thoroughly b
36、eforeuse.8.5 Certified standards, traceable to a national standardsbody such as the National Institute for Standards and Technol-ogy (NIST):8.5.1 Certified uranium standard (calibration), 1000 g/mL,used for preparation of calibration stock solutions and subse-quent calibration standards.C1844 1628.5
37、.2 Certified uranium standard (QC), 1000 g/mLused forpreparation of quality control/spike solutions, and independentfrom the standard in 8.5.1.8.5.3 Certified thorium standard, 1000 g/mL, used forpreparation of an internal reference standard. An element otherthan thorium may be used as the internal
38、reference in whichcase this standard would be substituted by an equivalentcertified standard containing the element to be used.8.6 Uranium Stock Solution, 5 g/mL, for CalibrationStandards (it is recommended to prepare every 6 months). Add50 mL of dilute nitric acid, 0.32 M, UHP to a thoroughlycleane
39、d 100 mL volumetric flask. Pipet 0.5 mL of certifieduranium standard (calibration), 1000 g/mL, into the flask anddilute to volume with dilute nitric acid, 0.32 M, UHP. Mixthoroughly and transfer to a labelled 125 mL bottle.8.7 Uranium Quality Control Spike Solution, 1 g/mL, (it isrecommended to prep
40、are every 6 months). Add 50 mL ofdilute nitric acid, 0.32 M, UHPto a thoroughly cleaned 100 mLvolumetric flask. Pipet 0.1 mL of certified uranium standard(QC), 1000 g/mL, into the flask and dilute to volume withdilute nitric acid, 0.32 M, UHP. Mix thoroughly and transfer toa labelled 125 mL bottle.8
41、.8 Thorium Internal Reference Standard Stock Solution, 2g/mL, (it is recommended to prepare every 6 months). Add50 mL of dilute nitric acid, 0.32 M, UHP to a thoroughlycleaned 100 mL volumetric flask. Pipet 0.2 mL of certifiedthorium standard, 1000 g/mL, into the flask and dilute tovolume with dilut
42、e nitric acid, 0.32 M, UHP. Mix thoroughlyand transfer to a labelled 125 mL bottle.8.9 Uranium Stock Solution, 5 g/L, for Calibration Stan-dards (it is recommended to prepare every 3 months). Add 50mL of dilute nitric acid, 0.32 M, UHP to a thoroughly cleaned100 mL volumetric flask. Pipet 0.1 mL of
43、the Uranium StockSolution, 5 g/mL, for Calibration Standards into the flask anddilute to volume with dilute nitric acid, 0.32 M, UHP. Mixthoroughly and transfer to a labelled 125 mL bottle.8.10 Uranium Instrument Quality Control/Spike Solution, 1g/L, (it is recommended to prepare every 3 months). Ad
44、d 50mL of dilute nitric acid, 0.32 M, UHP to a thoroughly cleaned100 mL volumetric flask. Pipet 0.1 mL of the Uranium QualityControl Spike Solution, 1 g/mL, into the flask and dilute tovolume with dilute nitric acid, 0.32 M, UHP. Mix thoroughlyand transfer to a labelled 125 mL bottle.8.11 Thorium In
45、ternal Reference Standard, 2 g/L.Add 50mL of dilute nitric acid, 0.32 M, UHP to a thoroughly cleaned100 mL volumetric flask. Pipet 0.1 mL of the Thorium InternalReference Standard Stock Solution, 2 g/mL into the flask anddilute to volume with dilute nitric acid, 0.32 M, UHP. Mixthoroughly and transf
46、er to a labelled 125 mL bottle.NOTE 2Instructions for the preparation and use of reference materialsand standards throughout this method are based upon the concentrationsgiven for the certified standards. The laboratory may choose to usedifferent concentrations and preparation schemes to prepare sta
47、ndards andspikes that suit its purposes. It is the responsibility of the laboratory toadjust dilutions to deliver the required concentration of uranium orinternal reference standard.9. Hazards9.1 Strong acids are used to prepare solutions used in thisanalysis. Safety glasses and gloves must be worn
48、whenhandling these solutions.9.2 Fumes and splashes of urine present a possible biologi-cal hazard. Gloves should be worn when handling urinesamples. Work should be carried out in a dedicated area,preferably within a fume hood, which should be cleanedregularly. Samples and waste items contaminated w
49、ith urineshould be disposed of appropriately.9.3 The ICP-MS is a source of intense ultra-violet radiationfrom the radio frequency induced plasma. Protection fromradio frequency radiation and UV radiation is provided by theinstrument under normal operation.10. Preparation of Apparatus10.1 All flasks to be used for preparation of stock solutionsand quality control spike solutions should be left soaking indilute nitric acid, 0.32 M, UHP. Before use, the flasks should berinsed three times with demineralized water.11. Calibration and Standardization11.
