ASTM_E_2937_-_18.pdf

Designation:E293718Standard Guide forUsing Infrared Spectroscopy in Forensic PaintExaminations1This standard is issued under the fixed designation E2937;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.INTRODUCTIONInfrared(IR)spectroscopy is commonly used by forensic laboratories for the analysis of paints andcoatings received in the form of small chips,residues,particles,or smears,and serves as a staplecomparative technique in the assessment of whether or not questioned paint could have come from aparticular source.IR spectroscopy provides molecular structure information on many of the organicand inorganic constituents contained within a single paint layer.This information can be used toclassify both binders and pigments in coating materials.The classification information can then beused to identify probable types of paint such as architectural,automotive,or maintenance.Additionally,the use of automotive paint databases allow for the determination of information suchas potential vehicle year,make and model.Databases can also aid in the interpretation of thesignificance(for example,how limited is the group of potential donor sources)of a questioned paint.1.Scope1.1 This guide applies to the forensic IR analysis of paintsand coatings and is intended to supplement information pre-sented in the Forensic Paint Analysis and Comparison Guide-lines(1)2written by Scientific Working Group on MaterialsAnalysis(SWGMAT).This guideline is limited to the discus-sion of Fourier Transform Infrared(FTIR)instruments andprovides information on FTIR instrument setup,performanceassessment,sample preparation,analysis and data interpreta-tion.It is intended to provide an understanding of therequirements,benefits,limitations and proper use of IR acces-sories and sampling methods available for use by forensic paintexaminers.The following accessory techniques will be dis-cussed:FTIRmicrospectroscopy(transmissionandreflectance),diamond cell and attenuated total reflectance.Theparticular methods employed by each examiner or laboratory,or both,are dependent upon available equipment,examinertraining,specimen size or suitability,and purpose of examina-tion.This guideline does not cover the theoretical aspects ofmany of the topics presented.These can be found in texts suchas An Infrared Spectroscopy Atlas for the Coatings Industry(Federation of Societies for Coatings,1991)(2)and FourierTransform Infrared Spectrometry(Griffiths and de Haseth,1986)(3).1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3D16 Terminology for Paint,Related Coatings,Materials,andApplicationsE131 Terminology Relating to Molecular SpectroscopyE1421 Practice for Describing and Measuring Performance1This guide is under the jurisdiction of ASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved Feb.1,2018.Published February 2018.Originallyapproved in 2013.Last previous edition approved in 2013 as E2937 13.DOI:10.1520/E2937-18.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 of Fourier Transform Mid-Infrared(FT-MIR)Spectrom-eters:Level Zero and Level One TestsE1492 Practice for Receiving,Documenting,Storing,andRetrieving Evidence in a Forensic Science LaboratoryE1610 Guide for Forensic Paint Analysis and Comparison3.Terminology3.1 Definitions