ASTM D5811-2008 317 Standard Test Method for Strontium-90 in Water《测定水中锶-90的标准试验方法》.pdf

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1、Designation: D 5811 08An American National StandardStandard Test Method forStrontium-90 in Water1This standard is issued under the fixed designation D 5811; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.

2、 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 determination ofradioactive90Sr in environmental water samples (for example,non-process and effluent wa

3、ters) in the range of 0.037 Bq/L(1.0 pCi/L) or greater.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This test method has been used successfully with tapwater. It is the users responsibility to ensure the validity of

4、thistest method for samples larger than 1 L and for waters ofuntested matrices.1.4 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 dete

5、rmine the applica-bility of regulatory limitations prior to use. For specific hazardstatements, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 1890 Test Method for Beta Particle Radioactivity ofWaterD 2777 Practice

6、 for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD 3370 Practices for Sampling Water from Closed ConduitsD 3648 Practices for the Measurement of RadioactivityD 4448 Guide for Sampling Ground-Water MonitoringWellsD 5847 Practice for Writing Quality Control S

7、pecificationsfor Standard Test Methods for Water AnalysisD 6001 Guide for Direct-Push Ground Water Sampling forEnvironmental Site CharacterizationD 7282 Practice for Set-up, Calibration, and Quality Con-trol of Instruments Used for Radioactivity Measurements3. Terminology3.1 DefinitionsFor definitio

8、ns of terms used in this testmethod, refer to Terminology D 1129.4. Summary of Test Method4.1 This test method is based on the utilization of solidphase extraction of strontium from water samples with detec-tion of the radioactive strontium by gross beta gas proportionalcounting.4.2 An aliquant of t

9、he sample is measured into a beaker,strontium carrier added, digested with nitric acid, sorbed on anion exchange column, eluted, evaporated to dryness, dissolvedin nitric acid (8M), selectively sorbed on a solid phaseextraction column, eluted with dilute nitric acid, dried on aplanchet, and counted

10、for beta radiation.4.3 Fig. 1 shows a flow diagram for this method.5. Significance and Use5.1 This test method was developed to measure the concen-tration of90Sr in non-process water samples. This test methodmay be used to determine the concentration of90Sr in environ-mental samples.6. Interferences

11、6.1 Significant amounts of stable strontium present in thesample will interfere with the yield determination. If it isknown or suspected that natural strontium is present in thesample at levels that will compromise the determination of thechemical yield, blank sample aliquots to which no strontiumca

12、rrier is added shall be analyzed to determine the natural1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.04 on Methods of Radiochemi-cal Analysis.Current edition approved April 1, 2008. Published May 2008. Originallyappro

13、ved in 1995. Last previous edition approved in 2000 as D 5811 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM webs

14、ite.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.strontium content. The amount of natural strontium containedin the sample shall be reflected when calculating the yieldcorrection factor.6.2 Strontium-89 present in the sample will

15、cause a highbias in proportion to the89Sr/90Sr ratio. This technique is notapplicable when it is suspected or known that89Sr is present inthe sample.6.3 Strontium nitrate (Sr(NO3)2) is hygroscopic. Thischemical property may add uncertainty in the gravimetric yielddetermination.7. Apparatus7.1 Analyt

16、ical Balance, 0.0001 g.7.2 Low Background Gas Proportional Beta Counting Sys-tem.7.3 Ion Exchange Columns, 10 mL resin capacity, glass oracid-resistant plastic.An attached reservoir of at least 50 mL isdesirable.FIG. 1 Flow Diagram for the ProcedureD58110827.4 Planchets, stainless steel to match cal

17、ibration source.38. 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 specifications of the Committeeon Analytical Reagents of the American Chemical Society.4Other grades may be

18、used, provided it is first ascertained thatthe reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the determination. Reagentblanks shall be run with all determinations.8.2 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean

19、reagent water conformingto Specification D 1193, Type III.8.3 Cation Exchange Resin, 100 to 200 mesh, hydrogenform. 8% cross linked, analytical grade.8.4 Nitric Acid (8M HNO3) Add 500 mL of concentratedHNO3to 400 mL of water. Dilute to 1L with water.8.5 Nitric Acid (0.1 HNO3)Add 6.4 mL of concentrat

20、edHNO3to 600 mL of water. Dilute to 1L with water.8.6 Nitric Acid (0.05M HNO3)Add 3.2 mL of concen-trated HNO3to 600 mL of water. Dilute to 1L with water.8.7 Strontium Carrier (10 g/L)Preferably use 10 000g/mL ICP standard. Alternatively, dissolve 24.16 g strontiumnitrate (Sr(NO3)2) in water, add 20

21、 mLconcentrated nitric acid,and dilute with water to 1 L. Use the following procedure tostandardize the prepared strontium carrier: Carefully pipet a5.0 mL portion of the strontium carrier solution onto a clean,dried, and tared planchet. Dry the planchet under the sameconditions used for the final e

22、vaporation in 12.20. Allow theplanchet to cool to room temperature and reweigh the planchetto the nearest 0.0001 g. Divide the net weight by 10. This resultis the amount of strontium nitrate actually added. Use anaverage of three values in the denominator of the recoveryequation in 11.12 and 13.1. T

23、his value should be within 3 % of12.08 mg/0.5 mL.8.8 Strontium Extraction Chromatography Column,2mLbed volume consisting of an octanol solution of 4,4(5)-bis(t-butyl-cyclohexano)-18-crown-6-sorbed on an inert poly-meric support.58.9 Strontium-90 Standardizing SolutionTraceable to anational standard

24、body such as National Institute of Standardsand Technology or National Physical Laboratory solution withless than 0.1 mg of stable strontium per mL of final solutionwith a typical concentration range from 85 to 125 Bq/mL.9. Hazards9.1 Use extreme caution when handling all acids. They areextremely co

25、rrosive and skin contact could result in severeburns.9.2 When diluting concentrated acids, always use safetyglasses and protective clothing, and add the acid to the water.10. Sampling10.1 Collect a sample in accordance with Practice D 3370,D 4448, D 6001, or other documented procedure.11. Calibratio

26、n11.1 Calibrate the low background gas proportional betacounting system in accordance with Practice D 7282. Prepare aset of three calibration samples according to the calibrationprocedure outlined in the subsequent steps.11.2 Pipet 0.5 mL of strontium carrier into a small beaker.11.3 Add 1 mL of tra

27、ceable90Sr solution and evaporate tonear dryness on a hot plate.11.4 Redissolve the residual in 5 mL of 8M nitric acid.11.5 Follow the steps described in 12.10 through 12.23.11.6 Count to accumulate 10 000 net counts in the countingperiod. Counting should be completed within3hofcolumnelution. Record

28、 the time and date of the midpoint of thiscounting period as t2. Count each sample mount twice, once forthis step having a counting date designated as t2and a secondtime as specified below.11.7 Calculate the net count rate of the count at timet2(Rn(2) by subtracting the instrument background count r

29、atefrom the gross count rate.11.8 Store the calibration mount for at least 7 days to allowfor90Y ingrowth.11.9 Recount the calibration mount to amass 10 000 countsin a counting period. Record the time and date of the midpointof this count period as t3.11.10 Calculate the net count rate of the second

30、 count attime t3(Rn(3) by subtracting the instrument background countrate from the gross count rate.11.11 Calculate the90Sr detection efficiency, eSr, andthe90Y detection efficiency, eY, for each calibration mountusing the equations presented below. Calculate the mean andstandard deviation of the th

31、ree eSrand eYvalues. Use therelative standard deviation of these parameters to estimate therelative uncertainty of the ingrowth efficiency factor, (definedin Eq 5), ur(eI) and used in Eq 7.11.12 Effciency Calculations:90Sr detection efficiency eSreSr5Rn2!3 IF3! 2 Rn3!3 IF2!YSr3 AC2!3 IF32 IF2!(1)90Y

32、 detection efficiency eYeY5Rn3!2 Rn2!YSr3 AC2!3 IF3 IF2!(2)where:AC(2)= activity of90Sr in becquerels (Bq) at the time ofthe first count of the calibration mount,3Stainless steel planchets available commercially have been found satisfactory.4Reagent Chemicals, American Chemical Society Specification

33、s, AmericanChemical Society, Washington, 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, In

34、c. (USPC), Rockville,MD.5The sole source of supply of the apparatus known to the committee at this timeis Sr Resin available from EichromTechnologies, Inc. If you are aware of alternativesuppliers, please provide this information to ASTM International Headquarters.Your comments will receive careful

35、consideration at a meeting of the responsibletechnical committee,1which you may attend.D5811083IF2= ingrowth factor for90Y at the midpoint of thecount at time t2,1elY3 t2 t1!#IF3= ingrowth factor for90Y at the midpoint of thecount at time t3,1elY3 t3 t1!#lY= decay constant for90Y (0.2600 d1),Rn(2)=

36、net count rate of the calibration test source at themidpoint of the first count, in counts per second,Rn(3)= net count rate of calibration test source at themidpoint of the second count, in counts persecond,t1= date and time of90Y separation,t2= date and time of midpoint of first count,t3= date and

37、time of midpoint of second count.YSr= fractional chemical yield of strontium carrier (seeEq 4).NOTE 1The time differences (t2 t1) and (t3 t1) are expressed indays.12. Procedure12.1 Add 0.5 mL of strontium carrier to a maximum of 1 Lof sample. Add 1 mL of 8M HNO3per 100 mL of sample andmix. Bring sam

38、ple to a boil for 30 min and then cool.12.2 Prepare a cation exchange column containing 10 mLofcation exchange resin.12.3 Precondition the column by passing 50 to 55 mL of0.1M HNO3through the column.12.4 Pass the sample through the column at a rate of notmore than 5 mL/min.12.5 Rinse the column with

39、 25 to 30 mL of 0.1M HNO3.12.6 Properly dispose of the feed and rinse.12.7 Elute the strontium (and other cations) with 50 mL of8M HNO3into a 150 mL beaker.12.8 Evaporate the eluate to near dryness on a hot plate in afume hood. The residue will dissolve more easily in the nextstep if the evaporation

40、 is stopped just as the sample starts to godry.12.9 Dissolve the salts in 5 mL of 8M HNO3. If necessary,cover with a watchglass and heat gently to facilitate completedissolution.12.10 Prepare a strontium extraction chromatography col-umn by removing the bottom plug and the cap. Press the topfrit dow

41、n snugly to the resin surface using a glass rod (orequivalent) and let the water drain out. Add 5 mL ofHNO3(8M) and let the solution drain by gravity.12.11 Carefully transfer the sample solution to the reservoirof the column.Add half and let the solution drain before addingthe second half.12.12 Rins

42、e the beaker with 3 mL of 8M HNO3and add tothe column after the feed has passed through.12.13 Repeat step 12.12.12.14 Rinse the column with 10 mL of 8M HNO3.12.15 Record the end time of the last rinse as the timeof90Y separation (start of90Y ingrowth, t1).12.16 Elute the strontium with two 5 mL port

43、ions of 0.05MHNO3into a suitable container (for example, a liquid scintil-lation counting vial or centrifuge tube).12.17 Clean a planchet with a paper towel moistened withalcohol. Wipe the planchet and let it dry.12.18 Weigh the planchet to the nearest 0.0001 g and recordthe weight.12.19 Place the p

44、lanchet under a heat lamp in a fume hood.12.20 Evaporate the strontium eluate (see 12.16) onto theplanchet by adding small portions (approximately 3 mL) to theplanchet and allowing each portion to evaporate to neardryness between additions.12.21 Rinse the liquid scintillation counting vial or centri

45、-fuge tube with approximately 3 mLof 0.05M HNO3, add to theplanchet and evaporate.12.22 After all the solution has dried, cool the planchet toroom temperature and reweigh the planchet. Record the weightto the nearest 0.0001 g.12.23 Beta count the sample as soon as possible afterpreparation on a low

46、background gas proportional countingsystem. Count an empty planchet for an equal length of time tomeasure the instruments beta background count rate. (See TestMethod D 1890 and Practices D 3648.)13. Calculation13.1 Strontium-90 Radioactivity Concentration (ACSr):ACSr5Ra RbeI3 Va3 YSr3 e2lSr3 t1 t0!#

47、(3)YSr5ma mbmc(4)eI5eSr1 eY3 1e2lY3 tm t1!#! (5)where:eSr= the mean of the values calculated using Eq 1,eY= the mean of the values calculated using Eq 2,eI= ingrowth efficiency factor,lSr= decay constant for90Sr (6.594 3 105d1),6lY= decay constant for90Y (0.2595 d1),Ra= count rate of sample aliquant

48、, in counts per second,Rb= count rate of instrument background, in counts persecond,t0= date and time of sample collection,t1= date and time of90Y separation,tm= midpoint of count of sample aliquant (date andtime),Va= volume of sample aliquant, in litres,YSr= fractional chemical yield of strontium c

49、arrier,ma= mass of Sr(NO3)2for the sample aliquant,mb= mass of Sr(NO3)2for the blank (where appropriatesee Step 6.1), andmc= mass of Sr(NO3)2added as carrier.NOTE 2The time differences (t1t0) and (tmt1) are expressed indays.13.2 The result of the measurement has an uncertainty dueto counting statistics (counting uncertainty). The standarduncertainty of the90Sr radioactivity concentration in thesample due to counting statistics, ucC(ACSr), is given by:ucCACSr! 5Ra1 RbtaeI3 Va3 YSr3 elSr3 tl t0!#(6)6Firestone, R.B., an