ASTM_D_5174_-_07_2013.pdf

Designation:D517407(Reapproved 2013)Standard Test Method forTrace Uranium in Water by Pulsed-Laser Phosphorimetry1This standard is issued under the fixed designation D5174;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 test method covers the determination of totaluranium,by concentration,in water within the calibrated rangeof the instrument,0.1 g/Lor greater.Samples with uranium bymass,levels above the laser phosphorimeter dynamic range arediluted to bring the concentration to a measurable level.1.2 This test method was used successfully with reagentwater.It is the users responsibility to ensure the validity of thistest method for waters of untested matrices.1.3 The values stated in SI units are to be regarded as thestandard.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: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 ConduitsD3856 Guide for Management Systems in LaboratoriesEngaged in Analysis of WaterD4448 Guide for Sampling Ground-Water Monitoring WellsD5847 Practice for Writing Quality Control Specificationsfor Standard Test Methods for Water AnalysisD6001 Guide for Direct-Push Groundwater Sampling forEnvironmental Site CharacterizationE131 Terminology Relating to Molecular Spectroscopy3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method,referto Terminologies D1129 and E131.3.1.2 For terms not defined in this test method or inTerminology D1129 or E131,reference may be made to otherpublished glossaries.34.Summary of Test Method4.1 This test method is based on the utilization of a laserphosphorimeter to determine total uranium,by mass,in watersamples.4.2 Asample aliquant is pipetted into a pretreated glass vial.Concentrated HNO3and hydrogen peroxide are added and thesample heated to dryness.This step is repeated as necessaryand the residue is dissolved in dilute HNO3.A complexant isadded to an aliquant of this sample and analyzed in thephosphorimeter.4.3 For screening purposes only,an aliquant of the samplemay be pipetted directly into the phosphorimeter cell contain-ing uranium complexant and read.This cannot be done if thesample was preserved with HCl or if the matrix is not known.5.Significance and Use5.1 This test method is useful for the analysis of totaluranium in water following wet-ashing,as required,due toimpurities or suspended materials in the water.6.Interferences6.1 Absorption(Inner Filter Effect)This effect is moresevere with ultraviolet excitation light(337 nm)than withvisible excitation because many prevalent compounds havepi-bonding and absorb strongly in this region.Ferric iron andoxy-anions such as nitrate and organic acids are examples.Visible excitation(425 nm)may be absorbed by yellowsolutions,for example,chromate.The consequences of thismay be reduced signals and low analysis results.6.2 LumiphorsMany organic substances,such as humicacids and organic degradation products from incomplete ashing1This 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 Jan.1,2013.Published January 2013.Originallyapproved in 1991.Last previous edition approved in 2007 as D5174 07.DOI:10.1520/D5174-07R13.2For 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.3See American National Standard Glossary of Terms in Nuclear Science andTechnology(ANSI N1.1),available from American National Standards Institute,1430 Broadway,New York,NY 10014,www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 emit luminescence of varying lifetimes after excitation.Anadvantage of kinetic phosphorescence measurement is theability to determine if interferences are present by observingthe lifetime of the decay.6.3 QuenchingShortened triplet-state lifetime and reducedphosphorescence intensities of the excited uranyl complexresult when quenching occurs.Reliable results cannot beobtained when quenching exceeds 80 to 90%.Reducing agentssuch as alcohols,halides except fluoride,and metals withelectronic energy levels overlappin