ASTM D4107-2008(2013) Standard Test Method for Tritium in Drinking Water《饮用水中氚含量的试验方法》.pdf

1、Designation: D4107 08 (Reapproved 2013)Standard Test Method forTritium in Drinking Water1This standard is issued under the fixed designation D4107; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number

2、 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 tritium indrinking water by liquid scintillation counting of the tritiumbeta particle activity.1

3、.2 This test method is used successfully with drinkingwater. It is the users responsibility to ensure the validity of thistest method for untested water matrices.1.3 The tritium concentrations, which can be measured bythis test method utilizing currently available liquid scintillationinstruments, ra

4、nge from less than 0.037 Bq/mL (1 pCi/mL) to555 Bq/mL (15 000 pCi/mL) for a 10-mL sample aliquot.Higher tritium concentrations can be measured by diluting orusing smaller sample aliquots, or both.1.4 The maximum contaminant level for tritium in drinkingwater as given by the United States Environment

5、al ProtectionAgency (U.S. EPA) National Interim Primary Drinking WaterRegulations (NIPDWR) is 0.740 Bq/mL (20 pCi/mL). TheNIPDWR lists a required detection limit for tritium in drinkingwater of 0.037 Bq/mL(1 pCi/mL), meaning that drinking watersupplies, where required, should be monitored for tritiu

6、m at asensitivity of 0.037 Bq/mL (1 pCi/mL). In Appendix X1, EqX1.3 is given for determining the necessary counting time tomeet the required sensitivity for drinking water monitoring.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisst

7、andard.1.6 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.2. Refer

8、enced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD2777 Practice for Determination of Precision and Bias ofApplicable Test Methods of Committee D19 on WaterD3370 Practices for Sampling Water from Closed ConduitsD3648 Practices for the Measurem

9、ent of Radioactivity3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D1129. For terms not defined inthis test method or in Terminology D1129, reference may bemade to other published glossaries.34. Summary of Test Method4.1 In this test method, a 100

10、-mL drinking water samplealiquot is treated with a small amount of sodium hydroxide andpotassium permanganate, distilled, and a specified fraction ofthe distillate is collected for tritium analysis. The alkalinetreatment is to prevent other radionuclides, such as radioiodineand radiocarbon from dist

11、illing over with the tritium. Somedrinking water supplies will contain trace quantities of organiccompounds, especially surface water sources that contain fishand other life. The permanganate treatment is to oxidize traceorganics in the sample aliquots which could distill over andcause quenching int

12、erferences. A middle fraction of the distil-late is collected for tritium analysis because the early and latefractions are more apt to contain interfering materials for theliquid scintillation counting process.4.2 As the sample distills, there is a gradient in the tritiumconcentration in the accumul

13、ating distillate due to isotopeeffects; therefore, it is important to collect the same fraction ofthe distillate for all samples and standards for tritium analysis.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.04 on Met

14、hods of Radiochemi-cal Analysis.Current edition approved June 15, 2013. Published July 2013. Originallyapproved in 1991. Last previous edition approved in 2008 as D4107 08. DOI:10.1520/D4107-08R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service a

15、t serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3American National Glossary of Terms in Nuclear Science and Technology,available from American National Standards Institute (ANSI), 25 W. 43rd St., 4thFloor, New Yo

16、rk, NY 10036, www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.3 The collected distillate fraction is thoroughly mixed anda portion (up to 10 mL) is mixed with liquid scintillatorsolution, and after dark adapting, is cou

17、nted in the liquidscintillation counting system for tritium beta particle activity.5. Significance and Use5.1 This test method was developed for measuring tritium inwater to determine if the concentration exceeds the regulatorystatutes of drinking water. This test method also is applicablefor the de

18、termination of tritium concentration in water asrequired by technical specifications governing the operations ofnuclear power facilities. With suitable counting technique,sample size, and counting time a detection limit of less than 37Bq/L (1000 pCi/L) is attainable by liquid scintillation.6. Interf

19、erences6.1 A reduced detection efficiency may result from quench-ing in the sample scintillator mixture. Quenching is caused byimpurities in the sample, which can inhibit the transfer ofenergy, or by colored materials, which may absorb some of theemitted light. Corrections for quenching can be made

20、by theuse of internal standards3or by the ratio method.4Theapproach described in this test method, distillation after alka-line permanganate treatment, eliminates quenching substances,as well as radionuclides which might be present in a volatilechemical form such as radioiodine and radiocarbon. A bo

21、ilingchip must be used with each distillation to avoid bumping,which can amount to a carry over excursion.6.2 Scintillator stock solution or samples exposed to day-light must be dark-adapted. Also, toluene or xylene basescintillators exposed to fluorescent lighting should be dark-adapted for a minim

22、um of 6 h and dioxane base scintillatorsexposed to fluorescent lighting for 24 h. All fluors should bechecked for excitation under lighting conditions being used,and if possible, they should be exposed only to red light.7. Apparatus7.1 Liquid Scintillation Spectrometer, coincidence-type.7.2 Liquid S

23、cintillation Vials, of low-potassium glass arerecommended. Polyethylene vials may be used when otherthan dioxane scintillator solution is used.7.3 Distillation ApparatusFor aqueous distillation,250-mL and 1000-mL round bottom borosilicate flasks, con-necting side arm adapter,5condenser, graduated cy

24、linder,boiling chips, and heating mantle.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

25、 Society,where such specifications are available.6Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be u

26、nderstood to mean reagent water conformingto Specification D1193, Type III.8.3 Reagents of Distillation Treatment:8.3.1 Sodium Hydroxide Pellets.8.3.2 Potassium Permanganate.8.4 Background Water, with tritium activity below theminimum detectable activity (most deep well waters are low intritium cont

27、ent).8.5 Scintillator Solutions:8.5.1 Dioxane Liquid Scintillator SolutionDissolve4gofscintillation-grade PPO (2,5-diphenyloxazole), 0.05 g ofscintillation-grade POPOP 1,4-bis (5-phenyloxazolyl-2-yl)-benzene, and 120 g of naphthalene in 1 L of spectroquality,1,4-dioxane. Store the solution in a dark

28、 (amber) bottle. Thissolution can be used with glass or polyethylene vials.8.5.2 Solution G Scintillator SolutionDissolve 18 g ofscintillation-grade PPO (2,5-diphenyloxazole) and 3.6 g ofscintillation-grade BIS-MSB p-bis (o-methylstyryl) benzenein 2 L of spectroquality p-xylene. Add 1 L of Triton N-

29、1017detergent to the p-xylene scintillator solution. Dissolve 50 g ofSXS (sodium xylene sulfonate) in 100 mL of water and addthis solution to the p-xylene scintillator-Triton solution. Mixthoroughly. Store the solution in a dark (amber) bottle. Thissolution should be used with glass vials since the

30、p-xylenesolvent evaporates slowly through the wall of the polyethylenevials.8.5.3 Other commercially available scintillators can beused, such as the environmentally safe di-isopropyl napthalenebased scintillators. It is the responsibility of the user to verifythe acceptability of a substitute scinti

31、llator.8.6 Tritium standard solution as tritiated water traceable toa National Standards Laboratory such as NIST or NPL,approximately 17 kBq/mL.9. Sampling9.1 Collect the sample in accordance with Practices D3370.9.2 Since tritium in drinking water is likely to be in the formof T2O or HTO, there is

32、no need for special handling orpreservation.4Bush, E. T., “General Applicability of the Channels Radio Method ofMeasuring Liquid Scintillation Counting Efficiencies,” Analytical Chemistry,Vol35, No. 1024, 1963.5Corning Part No. 9060 has been found satisfactory for this purpose.6Reagent Chemicals, Am

33、erican Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formula

34、ry, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.7The sole source of supply of the apparatus known to the committee at this timeis Rohm and Haas Company, Independence Mall West, Philadelphia, PA 19105. Ifyou are aware of alternative suppliers, please provide this information to ASTMInter

35、national Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.D4107 08 (2013)210. Calibration10.1 Determination of Recovery and Detection EffciencyFactors:10.1.1 Prepare in a 1-L volumetric flask, a tritium standardso

36、lution containing approximately 17 Bq/mL using low leveltritium background raw water, RWS (undistilled), and standardtritium activity. Label this solution as raw water tritiumstandard solution, RWTS.10.1.1.1 Distill approximately 600 mL of water obtainedfrom the same raw water source (RWS) as above

37、(withouttritium activity added). Use this distillate for backgroundtritium determinations. Using the distillate and standard tritiumactivity, prepare a tritium standard solution in a 500-mLvolumetric flask to contain the same specific activity as the rawwater tritium standard solution. Label this so

38、lution as distilledwater tritium standard solution, DWTS.10.1.2 Aqueous Alkaline Permanganate DistillationPlacea 100-mL aliquot of the RWTS solution in a 250-mL distilla-tion flask. Add 0.5 g of sodium hydroxide, 0.1 g of potassiumpermanganate, and a boiling chip. Proceed with the distillateaccordin

39、g to the procedure described in 11.1, discard 10 mL,and collect 50 mL of distillate for analysis. Mix the 50-mLdistillate fraction. Repeat the distillation with two more100-mLaliquots for triplicate analyses. This is the distilled rawwater tritium standard (DRWTS).10.1.3 Prepare for counting three a

40、liquots of the DRWTSdistillate tritium standard solution (from 10.1.2), three aliquotsof the DWTS, and three aliquots of the distilled raw water (forbackground). Mix 4 mL of water with 16 mL of the dioxanescintillator solution, or 10 mL of water with 12 mL of SolutionG scintillator solution in a liq

41、uid scintillator vial (glass vialsshould be used for detergent-type scintillator solutions). Shakewell, dark-adapt the vials overnight, and count in a liquidscintillation counter. Count each vial long enough to meet therequired detection (0.037 Bq/mL) or longer (see Appendix X1for calculating requir

42、ed counting time).11. Procedure11.1 Add 0.5 g of sodium hydroxide and 0.1 g of potassiumpermanganate to a 100-mL aliquot of the sample in a 250-mLdistillation flask. Add a boiling chip to the flask. Connect aside-arm adapter and a condenser to the outlet of the flask.Place a graduated cylinder at th

43、e outlet of the condenser. Heatthe sample to boiling to distill, collect the first 10 mL ofdistillate as a separate fraction and discard it.11.2 Collect the next 50 mLof distillate for tritium analysis.Thoroughly mix the 50-mL distillate fraction.NOTE 1It is important that only the first 10-mL fract

44、ion be discardedor the same fraction for samples and standards alike since there is agradient in the tritium concentration of the distillate.11.3 Thoroughly mix 4 mL of the distillate with 16 mL ofthe dioxane scintillator or 10 mL of distillate with 12 mL ofSolution G scintillator in a liquid scinti

45、llation vial. Threealiquots of each sample distillate should be analyzed fortritium.11.4 Prepare background standard tritium-water solutionsfor counting, using the same amount of water and the samescintillator as used in the preparation of samples. Use lowtritium background distilled water for these

46、 preparations (dis-tillate of most deep well water sources is acceptable, but eachsource should be checked for tritium activity before using).11.5 Dark-adapt all samples, backgrounds, and standards.Count the samples, backgrounds, and standards at least longenough to meet the required detection limit

47、 (0.037 Bq/mL) forthe sample (see Appendix X1 for calculating counting time forrequired detection limit). The DRWS distillate should becounted for sufficient time to accumulate at least 50 000 netcounts.12. Calculation12.1 Detection Effciency, : 5RDWTS2 RbADWTS(1)u! 5!RDWTStDWTS1RbtbADWTS212SuADWTS!

48、ADWTSD2where:ADWTS= activity of distilled water tritium standard, inbecquerels (Bq),Rb= background aliquot count rate, in counts persecond (s1),RDWTS= distilled water tritium standard count rate (s1),u(ADWTS) = standard uncertainty of the activity ADWTS(Bq),tDWTS= count time for the distilled water

49、tritium stan-dard (seconds), andtb= count time for the background sample(seconds).12.2 Recovery Correction Factor, F:F 5RDWTS2 Rb 3ARWTS(2)where:RDRWTS= count rate of distilled raw water standard (s1),andARWTS= activity of (undistilled) raw water tritium standardBq.12.3 Sample Tritium Activity, AC, for each aliquot:AC 5Ra2 Rb 3F 3V 3e2t(3)where:Ra= sample aliquot gross count rate (s1),Rb= background aliquot count rate (s1), = detection efficiency, as determined in Eq 1,V = volume of the sample aliquot (mL),F = recovery factor, as determined in Eq 2, =