1、Designation:E293713Standard 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 numb
2、er 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,
3、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 pa
4、int layer.This information can be used toclassify both binders and pigments in coating materials.The classification information may then beutilized to identify probable types of paint such as architectural,automotive,or maintenance.Additionally,the use of automotive paint databases may allow the det
5、ermination of information suchas potential vehicle year,make and model.Databases may 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
6、 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 F
7、TIR 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 accesso
8、ry 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 e
9、xamina-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
10、,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 establis
11、h appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3D16 Terminology for Paint,Related Coatings,Materials,andApplicationsE131 Terminology Relating to Molecular SpectroscopyE1421 Practice for Descr
12、ibing and Measuring Performanceof 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 Laboratory1This guide is under the jurisdiction of ASTM Committee E30 on ForensicSciences
13、 and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved Sept.1,2013.Published October 2013.DOI:10.1520/E2937-13.2The boldface numbers in parentheses refer to the list of references at the end ofthis standard.3For referenced ASTM standards,visit the ASTM we
14、bsite,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 E161
15、0 Guide for Forensic Paint Analysis and Comparison3.Terminology3.1 DefinitionsFor definitions of terms used in this guideother than those listed here,see Terminologies D16 and E131.3.2 Definitions of Terms Specific to This Standard:3.2.1 100%linecalculated by ratioing two backgroundspectra taken und
16、er identical conditions;the slope and noise of100%lines are used to measure the performance of theinstrument.3.2.2 absorbance(A)the logarithm to the base 10 of thereciprocal of transmittance T,written as A=log 10(1/T)=log10T.3.2.3 absorbance spectruma representation of the infraredspectrum in which the ordinate is defined in absorbance units(A);absorbance is linearly proportional to concentration and istherefore used in quantitative analysis.3.2.4 additive(modifier)any substance added in a small
