ASTM_E_2926_-_13.pdf

Designation:E292613Standard Test Method forForensic Comparison of Glass Using Micro X-rayFluorescence(-XRF)Spectrometry1This standard is issued under the fixed designation E2926;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.INTRODUCTIONOne objective of a forensic glass examination is to compare glass specimens to determine if theycan be discriminated using their physical,optical or chemical properties(for example,color,refractiveindex(RI),density,elemental composition).If the specimens are distinguishable,except foracceptable and explainable variations,in any of these observed and measured properties,it may beconcluded that they did not originate from the same source of broken glass.If the specimens areindistinguishable in all of these observed and measured properties,the possibility that they originatedfrom the same source of glass cannot be eliminated.The use of an elemental analysis method such asmicro X-ray fluorescence spectrometry(-XRF)yields high discrimination among sources of glass.1.Scope1.1 This test method is for the determination of major,minor,and trace elements present in glass fragments.Theelemental composition of a glass fragment can be measuredthrough the use of-XRF analysis for comparisons of glass.1.2 This test method covers the application of-XRF usingmono-and poly-capillary optics,and an energy dispersiveX-ray detector(EDS).1.3 This test method does not replace knowledge,skill,ability,experience,education,or training and should be used inconjunction with professional judgment.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 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:2E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE2330 Test Method for Determination of Concentrations ofElements in Glass Samples Using Inductively CoupledPlasma Mass Spectrometry(ICP-MS)for Forensic Com-parisons3.Summary of Test Method3.1-XRF is a nondestructive elemental analysis techniquebased on the emission of characteristic X-rays following theexcitation of the specimen by an X-ray source using capillaryoptics.Simultaneous multi-elemental analysis is typicallyachieved for elements of atomic number eleven or greater.3.2 Glass fragments usually do not require sample prepara-tion prior to analysis by-XRF.Cleaning of specimens may beperformed to remove any surface debris.3.3 Specimens are mounted and placed into the instrumentchamber and subjected to an X-ray beam.The characteristicX-rays emitted by the specimen are detected using an energydispersive X-ray detector and displayed as a spectrum ofenergy versus intensity.3.4 Qualitative analysis is accomplished by identifyingelements present in the specimen based on their characteristicX-ray energies.3.5 Semi-quantitative analysis is accomplished by compar-ing the relative area under the peaks of characteristic X-rays ofcertain elements.3.6 Spectral and elemental ratio comparisons of the glassspecimens are conducted for source discrimination or associa-tion.1This test method is under the jurisdiction ofASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved June 15,2013.Published July 2013.DOI:10.1520/E2926-13.2For 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 4.Significance and Use4.1-XRF provides a means of simultaneously detectingmajor,minor,and trace elemental constituents in small glassfragments such as those frequently examined in forensic casework.It can be used at any point in the analytical schemewithout concern for changing sample shape or sampleproperties,such as RI,due to its totally nondestructive nature.4.2 Limits of detection(LOD)are dependent on severalfactors,including instrument configuration and operatingparameters,sample thickness,and atomic number of theindividual elements.Typical LODs range from parts permillion(gg-1)to percent(%).4.3-XRF provides simultaneous qualitative analysis forelements having an atomic number of eleven or greater.Thismulti-element capability permits detection of elements typi-cally present in glass such as magnesium(Mg),silicon(Si),aluminum(Al),ca