1、Designation: C 1387 08Standard Guide forthe Determination of Technetium-99 in Soil1This standard is issued under the fixed designation C 1387; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in p
2、arentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide is intended to serve as a reference forlaboratories wishing to perform Tc-99 analyses in soil. Severaloptions are given for selection o
3、f a tracer and for the method ofextracting the Tc from the soil matrix. Separation of Tc fromthe sample matrix is performed using an extraction chroma-tography resin. Options are then given for the determination ofthe Tc-99 activity in the original sample. It is up to the user todetermine which opti
4、ons are appropriate for use, and togenerate acceptance data to support the chosen procedure.1.2 Due to the various extraction methods available, varioustracers used, variable detection methods used, and lack ofcertified reference materials for Tc-99 in soil, there is insuffi-cient data to support a
5、single method written as a standardmethod.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.2. Referenced Documents2.1 ASTM Standards:2C 859 Terminology Relating to Nuclear Materials3C 998 Practice for Sampling Surface Soil fo
6、r RadionuclidesC 999 Practice for Soil Sample Preparation for the Deter-mination of RadionuclidesD 1193 Specification for Reagent WaterE11 Specification for Wire Cloth and Sieves for TestingPurposes3. Terminology3.1 For definitions of terms in this guide, refer to Terminol-ogy C 859.4. Summary of Gu
7、ide4.1 There are no stable isotopes of technetium.Technetium-99 is produced by the fission of uranium andplutonium, and has been released to the environment vianuclear weapons testing and nuclear materials processing. Inan oxidizing environment, it exists as the very mobile pertech-netate ion, TcO4.
8、 Technetium-99 is a long-lived (half-life213,000 years), weak beta (beta max of 293 keV) emittingradioisotope.4.2 For the analysis of Tc-99 in soil, a tracer is added to thesample matrix, or spiked duplicate samples are prepared, andthen the Tc is extracted from the soil matrix by one of severalmeth
9、ods, including acid leaching or one of various fusionmethods. The resulting solution is passed through an extractionchromatography column. Technetium is known to be retainedby the extraction chromatography material while most otherelements pass through the column. The column is washed withdilute aci
10、d to remove any remaining interferents. The resinmay then be counted directly by adding it to a liquid scintil-lation cocktail and counting by liquid scintillation spectrom-etry, or the Tc may be eluted from the resin for alternativecounting or mass spectrometric techniques.5. Significance and Use5.
11、1 This guide offers several options for the determinationof Tc-99 in soil samples. Sample sizes of up to 200 g arepossible, depending on the method chosen to extract Tc fromthe soil matrix. It is up to the user to determine if it isappropriate for the intended use of the final data.6. Interferences6
12、.1 Any radionuclide not completely removed by the ex-traction chromatography column that has a beta decay energysimilar to or higher than Tc-99 will interfere when countingtechniques are used for quantification of the Tc-99 activity.6.2 Any elements with a mass-to-charge ratio (m/z) of 99(that is, n
13、aturally occurring isotope of Ru-99, or other artifi-cially produced elements of sufficient half-life with similarm/z) can interfere when using mass spectrometry for quantifi-cation of the Tc-99 activity. Any element with the same m/z asthe isotope used as an isotope dilution tracer or internalstand
14、ard will cause a bias in the yield correction. Correctionsshould be included in the mass spectrometry data reduction forknown interferences.6.3 Additional interferences may be encountered, depend-ing on the tracer and measurement technique chosen. It is up tothe user to determine and correct for any
15、 additional interfer-ences.1This guide is under the jurisdiction of ASTM Committee C26 on Nuclear FuelCycle and is the direct responsibility of Subcommittee C26.05 on Methods of Test.Current edition approved July 15, 2008. Published August 2008. Originallyapproved in 1998. Last previous edition appr
16、oved in 2003 as C 1387 03.2For 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 website.3Withdrawn.1Copyright ASTM Internat
17、ional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Apparatus7.1 Apparatus for the Extraction of Tc from Sample Matrix:7.1.1 See the individual extraction method descriptions tocompile a list of the equipment needed for the chosen extrac-tion method.7.2 Appa
18、ratus for the Purification of Tc from the SoilExtract:7.2.1 Extraction columnwith a bed volume of severalmilliliters for the extraction chromatography resin.47.2.2 Column extension funnelsthat can be added to theextraction column such that a few hundred milliliters ofsolution can be added to the col
19、umn at one time.7.2.3 Column rackholds columns such that several ex-tractions can be performed simultaneously.7.3 Apparatus for the Quantification of Tc-99:7.3.1 See the individual detection method descriptions tocompile a list of the equipment needed for the chosen detectionmethod.8. Reagents8.1 Pu
20、rity of ReagentsAll chemicals should, at a mini-mum, be of reagent grade and should conform to the specifi-cations of the Committee on Analytical Reagents of theAmerican Chemical Society where such specifications areavailable.5High Purity reagents are suggested if mass spec-trometry is chosen as the
21、 detection method. Other grades ofreagents may be used provided it is first determined that thereagent is of sufficient purity to permit its use without lesseningthe accuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent wa
22、ter, as definedby Type I of Specification D 1193.8.3 Tracer:8.3.1 Isotope Dilution Yield Determination:8.3.1.1 Radiometric Yield Determination Tc-95m6or Tc-99m7have been used to monitor the chemical yield of theextraction and purification of Tc-99 prior to quantification.Example: Add 10 nCi of Tc-99
23、m as a yield tracer whendetermining yield by gamma spectrometry.8.3.1.2 Mass Spectrometric Yield DeterminationTc-97may be produced in a nuclear reactor in very limited quantitiesto be used as an isotope dilution tracer for the mass spectro-metric determination of Tc-99 (1).8Example: Add 1 ng ofTc-97
24、 as a yield tracer for mass spectrometry.8.3.2 Duplicate Sample Analysis to Monitor Chemical Yield:8.3.2.1 Duplicate samples may be analyzed, one spiked witha known amount of Tc-99 and one unspiked. The chemicalrecovery of the spiked sample is then used to correct theunspiked sample to obtain the or
25、iginal sample activity.8.4 Reagents for the Extraction of Tc-99 from SampleMatrix:8.4.1 See the individual extraction method descriptions tocompile a list of the reagents needed for the chosen extractionmethod.8.5 Reagents for the Purification of Tc from the SampleMatrix:8.5.1 Extraction Chromatrogr
26、aphy Resin TEVA Resin.98.5.2 Prefilter Resina nonionic acrylic ester polymer resinused to remove residual organic matter prior to the extractionchromatography resin column.108.5.3 Hydrogen Peroxide30 %.8.5.4 Nitric Acid(HNO3) concentrated, specific gravity1.42.8.5.5 1M Nitric AcidAdd 63 mL of high p
27、urity HNO3to900 mL of DI water, dilute to a final volume of 1 liter.8.5.6 4M Nitric AcidAdd 250 mL of high purity HNO3to600 mL of DI water, dilute to a final volume of 1 liter.8.6 Reagents for the Quantification of Tc-99:8.6.1 See the individual detection method descriptions tocompile a list of the
28、reagents needed for the chosen detectionmethod.9. Procedure9.1 Collect samples in accordance with Specification C 998.9.2 Soil or Sediment Preparation:9.2.1 Oven dry samples at a temperature not to exceed105C and homogenized in accordance with SpecificationC 999.9.2.2 OptionalSamples may be placed i
29、n a muffle oven todecompose organic matter prior to the extraction of Tc. Themuffling techniques reported vary significantly (2-4).Ifde-sired, weigh 510 g of the sample be weighed in a hightemperature crucible. Add the chosen yield monitor and mixthe sample. Wet the sample with concentrated ammonium
30、hydroxide and mix, then dry under a heat lamp. It has beenfound that ammonium hydroxide will prevent the loss of thevolatile Tc at higher temperatures. Place the sample in a muffleoven for 24 hours at 500C (4), or for 3060 minutes at 600Cfollowed by the addition of a few grams of ammonium nitrateand
31、 10 more minutes of heating if traces of carbon remain (2).9.3 Tc Extraction These discussions are summaries fromavailable literature. The user must read the primary referencefor a complete discussion of the method prior to its use.9.3.1 Acid Leaching There are many reported acid leach-ing technique
32、s in the literature (2, 3, 5-9); however, only thosethat are easily coupled to the extraction chromatography4Prepacked columns from Eichrom Technologies, LLC, (Darien, IL) or BioRad(Richmond, CA) poly prep columns have been found satisfactory for this purpose.5Reagent Chemicals, American Chemical So
33、ciety Specifications, AmericanChemical Society, Washington, D. C. For suggestions on the testing of reagents notlisted by the American Chemical Society, Washington, D. C. For suggestions on thetesting of reagents not listed by the American Chemical Society, see AnalarStandards for Laboratory Chemica
34、ls, BDH Ltd., Poole, Dorset, U. K., and theUnited States Pharmacopeia and National Formulary, U.S. Pharmaceutical Con-vention (USPC), Rockville, MD.6Tc-95m may be obtained from Analytics, Inc., Atlanta, GA, or other suitablesupplier.7Tc-99m may be obtained from a local medical pharmacy supplier or o
35、thersuitable supplier.8The boldface numbers in parentheses refer to the list of references at the end ofthis standard.9The sole source of supply of the apparatus known to the committee at this timeis TEVA Resin from Eichrom Technologies, LLC. If you are aware of alternativesuppliers, please provide
36、this information to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,1which you may attend.10Prefilter columns are available from Eichrom Technologies, LLC or Amber-chrom GC-71CD resin has been found satisfactory for
37、this purpose.C 1387 082purification are described in 9.3.1.1-9.3.1.4. These methods aresummarized in the following four sections9.3.1.1 Weigh out up to 10 grams of soil to a 250 mL glassbeaker along with the desired yield monitor. Cover and heat thesample in the presence of 1M nitric acid.After cool
38、ing, removeresidual solid matter from the sample by centrifugation. Addhydrogen peroxide and sodium vanadate to each sample todestroy residual organic matter. Finally, reduce the acidity ofthe sample to less than 0.5M using ammonium hydroxide(dilute with water to a final sample volume of approximate
39、ly500 mL) (5).9.3.1.2 Add the desired yield monitor to 510 g of sample,which is then ashed using step 9.2.2. Leach the sample twicewith hot 8M nitric acid and hydrogen peroxide, combining theleachates. Adjust the pH to 7 with sodium hydroxide and filterthe solution through a glass fiber filter. Dilu
40、te the water toapproximately 500 mL (6).9.3.1.3 Weigh out up to 200 grams of sample. Add thedesired yield monitor.Ash using step 9.2.2. Transfer the sampleto a decomposition vessel. Add 6M nitric acid. Decompose thesample at 100120C for one hour. Filter the sample through aglass fiber filter then di
41、lute with water until the acid concen-tration is less than 0.5M nitric acid (at least 500 mL) (7).9.3.1.4 Weigh out one gram of the dried, unashed sample toa 250 mL conical flask. Add the desired yield monitor. Addconcentrated nitric acid and fit into a reflux condenser. Refluxthe sample until the b
42、rown fumes cease and all the organicmatter is dissolved. Cool the flask and pour the solution intowater. Neutralize the solution with sodium hydroxide, filter outany undissolved residue, and dilute to a final volume ofapproximately 250500 mL (8).9.3.2 Soil FusionThe following two methods have beenus
43、ed for Tc-99.9.3.2.1 Weigh out four grams of sample. Add the desiredyield monitor and ash using step 9.2.2. When cool, transfer thesample to a nickel crucible. Add 20 gram of the flux mixture(Na2CO3,K2CO3and NaNO3in a 3.92:5.08:1.00 weight ratio;the flux-to-sample ratio should be 5:1). Start the fus
44、ion byheating the crucible with the sample over a burner at high heat.When no further reaction is visible, cover the crucible andplace in a muffle over set at 900C for 30 minutes. Remove thesample from the oven and cool. Cover the crucible with awatch glass and add about 25 mL of water to the crucib
45、le tostart dissolving the cake and cover with a watch glass. Transferthe solution to a beaker and continue rinsing the crucible withwater until all the cake is rinsed into the beaker. Cover thebeaker and warm slightly if needed to complete the dissolution.Dilute with water to a final volume of about
46、 200250 mL (10).9.3.2.2 It is suggested that the sample be ground to passthrough a 45 micron standard test sieve as defined in Specifi-cation E11. This will result in a homogeneous sample with aparticle size that can be attacked by the fusion procedure.Weigh out 0.25 gram of sample to a zirconium cr
47、ucible. Addthe desired yield monitor. Add 2.25 gram of sodium peroxideand mix well. Place the crucible in a muffle oven preheated to470C. Heat for 30 minutes. Remove from the oven. Whencool, add about 40 mL of water. Allow the mixture to dissolvefor approximately one hour. Add 4 mL of concentrated n
48、itricacid to the crucible and dilute the solution to a final volume ofapproximately 150200 mL with water (11).9.3.3 Microwave DigestionThe following two methodshave been used for Tc-99.9.3.3.1 Weigh out 0.5 gram of sample into a microwavedigestion vessel. Add the desired yield monitor to the vessel.
49、Add 20 mL of 4M nitric acid to the bomb and swirl to mix thecontents. Place the bomb in a microwave and heat at moderatepower for 3060 minutes.11Let the vessels cool completelybefore venting and opening. Pour the solution to a beaker.Rinse the vessel with water and add to the sample beaker.Dilute to a final volume of 200250 mL such that the final acidsolution is less than 0.5M (12).9.3.3.2 Weigh out up to 0.5 gram of sample to a tared Teflonliner.Add the desired yield monitor to each sample.Add 10 mLof concentrated nitric acid to each sample. Al
