Designation:E2937−18StandardGuideforUsingInfraredSpectroscopyinForensicPaintExaminations1ThisstandardisissuedunderthefixeddesignationE2937;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONInfrared(IR)spectroscopyiscommonlyusedbyforensiclaboratoriesfortheanalysisofpaintsandcoatingsreceivedintheformofsmallchips,residues,particles,orsmears,andservesasastaplecomparativetechniqueintheassessmentofwhetherornotquestionedpaintcouldhavecomefromaparticularsource.IRspectroscopyprovidesmolecularstructureinformationonmanyoftheorganicandinorganicconstituentscontainedwithinasinglepaintlayer.Thisinformationcanbeusedtoclassifybothbindersandpigmentsincoatingmaterials.Theclassificationinformationcanthenbeusedtoidentifyprobabletypesofpaintsuchasarchitectural,automotive,ormaintenance.Additionally,theuseofautomotivepaintdatabasesallowforthedeterminationofinformationsuchaspotentialvehicleyear,makeandmodel.Databasescanalsoaidintheinterpretationofthesignificance(forexample,howlimitedisthegroupofpotentialdonorsources)ofaquestionedpaint.1.Scope1.1ThisguideappliestotheforensicIRanalysisofpaintsandcoatingsandisintendedtosupplementinformationpre-sentedintheForensicPaintAnalysisandComparisonGuide-lines(1)2writtenbyScientificWorkingGrouponMaterialsAnalysis(SWGMAT).Thisguidelineislimitedtothediscus-sionofFourierTransformInfrared(FTIR)instrumentsandprovidesinformationonFTIRinstrumentsetup,performanceassessment,samplepreparation,analysisanddatainterpreta-tion.Itisintendedtoprovideanunderstandingoftherequirements,benefits,limitationsandproperuseofIRacces-soriesandsamplingmethodsavailableforusebyforensicpaintexaminers.Thefollowingaccessorytechniqueswillbedis-cussed:FTIRmicrospectroscopy(transmissionandreflectance),diamondcellandattenuatedtotalreflectance.Theparticularmethodsemployedb...
