1、Designation: C 1343 96 (Reapproved 2007)Standard Test Method forDetermination of Low Concentrations of Uranium in Oilsand Organic Liquids by X-ray Fluorescence1This standard is issued under the fixed designation C 1343; the number immediately following the designation indicates the year oforiginal a
2、doption 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 test method covers the steps necessary for thepreparation and a
3、nalysis by X-ray fluorescence (XRF) of oilsand organic solutions containing uranium.1.2 The procedure is valid for those solutions containing 20to 2000 g uranium/mL as presented to the spectrometer.1.3 This test method requires the use of an appropriateinternal standard. Care must be taken to ascert
4、ain that samplesanalyzed by this test method do not contain the internalstandard or that this contamination, whenever present, has beencorrected for mathematically. Such corrections are not ad-dressed in this procedure. Care must be taken that the internalstandard and sample medium are compatible; t
5、hat is, samplesmust be miscible with tri-n-butyl phosphate (TBP) and mustnot remove the internal standard from solution.Alternatively, ascatter line may be used as the internal standard.21.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for info
6、rmationonly.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 of regulatory limitations prior to use. Sp
7、ecific precau-tionary statements are given in Section 9 and Note 2.2. Referenced Documents2.1 ASTM Standards:3C 982 Guide for Selecting Components for Energy-Dispersive X-Ray Fluorescence (XRF) SystemsC 1118 Guide for Selecting Components for Wavelength-Dispersive X-Ray Fluorescence (XRF) SystemsD 1
8、193 Specification for Reagent WaterE 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related Materials2.2 NIST Document:NBS Handbook 111, Radiation Safety for X-ray Diffractionand X-ray Fluorescence Analysis Equipment43. Terminology3.1 DefinitionsSee definitions in Terminology
9、E 135.4. Summary of Test Method4.1 Solution standards containing 20 g uranium/mL to2000 g uranium/mL and an internal standard are placed in aliquid sample holder of an X-ray spectrometer and exposed toan X-ray beam capable of exciting the uranium L-a emissionline and the appropriate internal standar
10、d line. The intensitiesgenerated are measured by an appropriate detector. The inten-sity ratio values obtained from these data are used to calibratethe X-ray analyzer. Samples are prepared having a similarmatrix to fit the calibration range and measured using the sameanalytical parameters.NOTE 1Yttr
11、ium, strontium, and bromine K-a and thorium L-a lineshave been used successfully as internal standard lines. Explanation of theinternal standard method of analysis is outside the scope of this testmethod and is found in several sources.5,65. Significance and Use5.1 This test method is applicable to
12、organic solutionscontaining 20 to 2000 g uranium/mL of solution presented tothe spectrometer.1This test method is under the 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, 2007. Publish
13、ed July 2007. Originally approvedin 1996. Last previous edition approved in 2002 as C 134396(2002).2Andermann, G., and Kemp, J. W., “Scattered X-rays as Internal Standards inX-ray Spectroscopy,” Analytical Chemistry , Vol 20, No. 8, 1958.3For referenced ASTM standards, visit the ASTM website, www.as
14、tm.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.4Available from U.S. Department of Commerce, National Institute of Standardsand Technology, Gaithersburg, MD 20899.5Bertin,
15、 E. P., Introduction to X-ray Spectrometric Analysis, Plenum Press, NewYork and London, 1978.6Tertian, R., and Claisse, F., Principles of Quantitative X-ray FluorescenceAnalysis, Heyden such cups decrease the likelihood of contamination of thesamples.7.2.2 Polyester, polyethylene, and polypropylene
16、films havebeen used successfully as the film window for such cups. Testsshould be performed to determine the serviceability of any filmchosen before the insertion of samples into the instrument.7.3 Solution Dispenser (Optional)If used, the solutiondispenser for the internal standard solution should
17、be capableof dispensing the internal standard reproducibly to a level of0.5 % relative standard deviation of the volume dispensed.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 t
18、he specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.7Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determinat
19、ion.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water in con-formance with Specification D 1193.8.3 Nitric Acid, HNO3, concentrated (70 %).8.4 1,3,5-Tribromobenzene, technical grade (or substitutefor internal standard).8.5 Tri-n-Butyl Phospha
20、te (TBP), technical grade.8.6 Uranium Oxide,U3O8, NBL CRM 129,8or equivalent.9. Technical Precautions9.1 X-ray fluorescence equipment analyzes by the interac-tion of ionizing radiation with the sample. Applicable safetyregulations and standard operating procedures must be re-viewed prior to the use
21、of such equipment. All current XRFspectrometers are equipped with safety interlock to preventaccidental penetration of the X-ray beam by the user. Do notoverride these interlocks (see NBS Handbook 111).9.2 Instrument performance may be influenced by environ-mental factors such as heat, vibration, hu
22、midity, dust, strayelectronic noise, and line voltage stability. These factors andperformance characteristics should be reviewed prior to the useof this test method.10. Preparation of Apparatus10.1 Chamber EnvironmentThe standards and samplesused in this test method are corrosive liquids. Some fumes
23、 willbe emitted from the sample cups. These fumes may bedetrimental to the spectrometer chamber. It is desirable to flushthis chamber with an inert gas (usually helium) before andduring analysis. Some X-ray spectrometers control the changeof sample chamber environment (air, vacuum, and helium)automa
24、tically through the software; in others, it must be donemanually. Follow the instrument manufacturers recommenda-tions to achieve the inert gas environment.NOTE 2Caution: Allow sufficient stabilization time before analysis.Care must be taken to ensure that a vacuum environment is not chosenwith liqu
25、id samples.10.2 X-ray Power SupplyIf the power to the X-ray tube isnot controlled by the instrument software, set the propercombination of voltage and current for the instrument in use.These settings must be ascertained by the user for his instru-ment and choice of X-ray tube. Rhodium, gold, tungste
26、n, andmolybdenum target X-ray tubes have been used successfullyfor this analysis. Allow sufficient stabilization time prior toanalysis.11. Calibration and Standardization11.1 Internal Standard Solution:11.1.1 Weigh 65.64 g of 1,3,5-tribromobenzene to the near-est 0.1 mg. Transfer the material to a 4
27、00-mL beaker; add 200mL of TBP.11.1.2 Dissolve the material in TBP; heat on a hot plate, ifnecessary.11.1.3 Transfer the dissolved material to a 1000-mL volu-metric flask, and dilute to volume with TBP. (Storage of thesolution in an opaque container with a screw cap is recom-mended; see Note 5.)11.2
28、 “Master” Standards:NOTE 3Because of the difficulty of accurately weighing the smallamounts of uranium oxide necessary for low-concentration standards,calibration standards are made by dilution from “master” standards. Thetotal volume of the standard prepared may be adjusted to meet the usersanalyti
29、cal throughput if the weights are adjusted appropriately.11.2.1 Prepare the standards at each desired concentrationlevel by weighing the quantities of uranium oxide given inTable 1 into 400-mL beakers.7Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington
30、, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.8Available from
31、 U.S. Department of Energy, New Brunswick Laboratory, D350,9800 South Cass Avenue, Argonne, IL 60439, Attn: Reference Material Sales.C 1343 96 (2007)211.2.2 Dissolve the oxide in 50 mL of water and 10 mL ofconcentrated nitric acid. Evaporate the solution to near drynessor to a syrupy solution.11.2.3
32、 Add enough TBP to bring the uranium back intosolution. (Keep the volume below 200 mL.)11.2.4 Transfer the solution to a 500-mL volumetric flaskusing TBP. When cool, add 1 mL of concentrated nitric acidwhile diluting to volume with TBP; cap and mix thoroughly.11.3 “Secondary Master” Standards:11.3.1
33、 Prepare a 500 g/mL standard by pipetting 25 mL ofthe 5000 g/mL “master” standard into a 250-mL volumetricflask. Dilute to volume with TBP, and mix thoroughly.11.3.2 Prepare a 100 g/mL standard by pipetting 25 mL ofthe 1000 g/mL “master” standard into a 250-mL volumetricflask. Dilute to volume with
34、TBP, and mix thoroughly.11.4 Calibration Standards:11.4.1 Prepare the calibration standards by pipetting intolabeled 50-mL volumetric flasks the amounts of each “master”standard given in Table 2.11.4.2 Add 2 mL of the internal standard to each flask.Dilute to volume with TBP, and mix thoroughly.NOTE
35、 4The internal standard solution may be added using anautomatic dispenser or dispensing pipet. However, care must be taken toensure that no adjustment to the dispenser is made between use forstandards and use for samples.11.5 Instrument Calibration:NOTE 5The frequency of calibration, use of blanks,
36、spikes andduplicates, labeling, and length of storage of solutions shall be inaccordance with the users quality assurance/quality control plan andrequirements.11.5.1 Follow the manufacturers instructions for the instru-ment in use to obtain intensity data for the uranium L-a and theinternal standard
37、 line for each standard.11.5.2 Care must be exercised that the analytical conditionsdetermined appropriate for the instrument in use are docu-mented, or recorded, in sufficient detail that these may bereproduced in subsequent runs and when analyzing thesamples.11.5.3 Calculate the uranium/internal s
38、tandard ratios fromthe data obtained in 11.5.1. Calculate a calibration curve usingthese ratios. The curve should be at least a second orderpolynomial (quadratic) or should have a term to correct foruranium self-absorption. Both have been found acceptable.Currently available instrument software woul
39、d contain one orthe other, or perhaps both. (A complete discussion of themathematical derivation of the following equations is outsidethe scope of this test method. Explanations of correctionmodels and interelement effects are found in severalsources.5,6) The quadratic equation will have the formY 5
40、 CX21 BX 1 A (1)where:Y = concentration of uranium,X = uranium/internal standard intensity ratio, andA,B,C = coefficients of quadratic equation.11.5.4 For self-absorption, the equation will have the formY 5 MX 1 B!1 1aX/100! (2)where:Y = concentration of uranium,X = uranium/internal standard intensi
41、ty ratio,M = slope of straight line,B = intercept of straight line, anda = self-absorption coefficient.NOTE 6Units used for Y in (Eq 1) and (2) may be changed, asappropriate, for the software in use.12. Procedure12.1 Sample Preparation:TABLE 1 “Master” Standards for Uranium in Organic LiquidsUranium
42、 Oxide, gAConcentration, g U/mL2.9490 50000.5898 1000AThe weight of uranium oxide is based on the value of NBL CRM 129. Weightswill need to be adjusted for the purity of the uranium reference material used.Follow instructions on the certificate accompanying the material for drying andpurity correcti
43、on, where applicable.TABLE 2 Calibration Standards for Uranium in Organic Liquids“Master” Standard Used,g U/mL“Master” StandardPipetted, mLCalibration StandardConcentration, g U/mL5000 20 20005000 15 15005000 10 10001000 25 500500 25 250500 10 100100 25 50100 10 20TABLE 3 Uranium in Tri-n-Butyl Phos
44、phate Solution (TheoreticalValue 0.01014 g U/g Solution)Observed Xi0.0102190.0102200.0101600.0102100.0101680.0102500.0103000.0103010.0101510.0101360.0100500.0101200.0101100.0100400.0100600.0101900.0100800.0102750.0103340.0102210.0100540.0101210.0100880.0102600.0101440.0101600.0102120.0101810.0101400
45、.010111X= 0.010169, s = 0.000080C 1343 96 (2007)312.1.1 Shake the sample and pipet an appropriate amountinto a tared 50-mL volumetric flask.NOTE 7Some estimate of the approximate g U/L will be necessary todetermine the appropriate dilution. This may be obtained by gammacounting of the incoming sampl
46、e, prior knowledge of the origin of thesample, or some other scheme devised by the user. Such schemes areoutside the scope of this test method.12.1.2 Obtain the gross weight of the sample and flask.(This may be omitted if an answer on a weight basis is notdesired.)12.1.3 Add 2 mL of the internal sta
47、ndard solution; dilute tovolume with TBP and mix thoroughly.12.2 Counting the Sample:12.2.1 Set the X-ray spectrometer to the conditions noted in11.5.2 above. If the analytical conditions are controlled bycomputer, start the computer in accordance with the manufac-turers instructions for the softwar
48、e in use.12.2.2 Shake each flask to mix thoroughly. Fill the liquidsample cup with the recommended amount of liquid for theinstrument in use.12.2.3 Following the manufacturers instrumental instruc-tions, obtain intensities for the uranium L-a line and theinternal standard line.12.2.4 Calculate the u
49、ranium concentration in the flaskusing the appropriate equation.NOTE 8Additional factors, such as volume, weight, isotopic correc-tion, and secondary dilutions, may be added to the listed equations toobtain results on the proper basis for the users application.13. Precision and Bias13.1 There is no readily available certified material (ura-nium in organic liquids) for this test method. However, asolution of NBL CRM 129 (U3O8) was prepared by dissolvingapproximately 5.9 g (weighed to the nearest 0.1 mg) asoutlined in 11.2. Thirty test samples of 5 mL
