ASTM_C_1387_-_14.pdf

Designation:C138714Standard Guide forthe Determination of Technetium-99 in Soil1This standard is issued under the fixed designation C1387;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 parentheses 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 perform99Tc analyses in soil.Severaloptions are given for selection of 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 ofthe99Tc activity in the original sample.It is up to the user todetermine which options 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 for99Tc in soil,there is insufficientdata to support a single method written as a standard method.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C859 Terminology Relating to Nuclear MaterialsC998 Practice for Sampling Surface Soil for RadionuclidesC999 Practice for Soil Sample Preparation for the Determi-nation of RadionuclidesD1193 Specification for Reagent WaterD7168 Test Method for99Tc in Water by Solid Phase Extrac-tion DiskE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3.Terminology3.1 For definitions of terms in this guide,refer to Terminol-ogy C859.4.Summary of Guide4.1 Therearenostableisotopesoftechnetium.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.Technetium-99 is a long-lived(half-life of2.1 E 5 years),weak beta(maximum beta energy of 293 keV)emitting radioisotope.4.2 For the analysis of99Tc 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 severalmethods,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 acid to remove any remaining interferents.The resinmay then be counted directly by adding it to a liquid scintil-lationcocktailandcountingbyliquidscintillationspectrometry,or the Tc may be eluted from the resin foralternative counting or mass spectrometric techniques.5.Significance and Use5.1 This guide offers several options for the determinationof99Tc 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.Interferences6.1 Any radionuclide not completely removed by the ex-traction chromatography column that has a beta decay energysimilar to or higher than99Tc will interfere when countingtechniques are used for quantification of the99Tc activity.6.2 Any elements with a mass-to-charge ratio(m/z)of 99(that is,naturally occurring isotope of99Ru or other artificiallyproduced elements of sufficient half-life with similar m/z)caninterfere when using mass spectrometry for quantification of1This 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 Jan.1,2014.Published February 2014.Originallyapproved in 1998.Last previous edition approved in 2008 as C1387 08.DOI:10.1520/C1387-14.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 the99Tc mass activity.Any element with the same m/z as theisotope used as an isotope dilution tracer or internal standardwill cause a bias in the yield correction.Corrections should beincluded in the mass spectrometry data reduction for knowninterferences.6.3 Additional interferences ma