This study investigated the use of laser-induced breakdown spectroscopy (LIBS) and scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDX) as means of characterizing gunshot residue (GSR) originating from commercially available lead-free rounds. Data from two experiments are presented in this work. One experiment focused on identifying prominent analytical markers present in lead-free GSR by LIBS while the other applied SEM-EDX to determine the degree of evidence preservation after LIBS analysis. Samples of GSR were collected via tape-lift method from the hands of volunteer shooters and instrumental analyses were conducted in triplicate. As a result, the lead-free ammunition analyzed in this work generated GSRs comprising primarily Ba, Al, Si, and/or K. Trace amounts of Ti, Fe, and S were also apparent in some compositions. Through SEM-EDX analysis, a spheroidal geometry consistent with traditional lead-containing GSR was observed. Additionally, it was determined that evidence is preserved after LIBS analysis which supports the implementation of LIBS as a rapid preliminary screening method followed by confirmatory testing via SEM-EDX on the preserved evidence.
“Standard Guide for Gunshot Residue Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry”. ASTM International: West Conshohocken, PA, July 2010.
2.
KaraI.SarikavakY.LisesivdinS.B.KasapM.“Evaluation of Morphological and Chemical Differences of Gunshot Residues in Different Ammunitions Using SEM/EDS Technique”. Environ. Forensics2016; 17(1): 68–79.
3.
BasuS.“Formation of Gunshot Residues”. J. Forensic Sci1982; 27(1): 72–91.
4.
BuenoJ.LednevI.K.“Attenuated Total Reflectance-FT-IR Imaging for Rapid and Automated Detection of Gunshot Residue”. Anal. Chem2014; 86: 3389–3396.
5.
DalbyO.ButlerD.BirkettJ.W.“Analysis of Gunshot Residue and Associated Materials-A Review”. J. Forensic Sci2010; 55(4): 924–943.
6.
PolovkovaJ.SimonicM.SzegenyiI.“Study of Gunshot Residues from Sintox® Ammunition Containing Marking Substances”. Egypt. J. Forensic Sci2014; 5(4): 174–179.
7.
BenitoS.AbregoZ.SanchezA.UncetaN.GoicoleaM.A.BarrioR.J.“Characterization of Organic Gunshot Residues in Lead-Free Ammunition Using a New Sample Collection Device for Liquid Chromatography–Quadrupole Time-of-Flight Mass Spectrometry”. Forensic Sci. Int2014; 246: 79–85.
8.
FrenchJ.MorganR.“An Experimental Investigation of the Indirect Transfer and Deposition of Gunshot Residue: Further Studies Carried Out with SEM–EDX Analysis”. Forensic Sci. Int2014; 247: 14–17.
9.
UnerH.B.OzaslanA.“Gunshot Residues of Blank Firing Pistols”. Trace Elements and Electrolytes2005; 22: 268–271.
10.
J.S. Wallace. “Priming Compositions”. In: Chemical Analysis of Firearms, Ammunition, and Gunshot Residue. Boca Raton, FL: CRC Press, 2008. Pp. 41–56.
11.
BellS.SeitzingerL.“From Binary Presumptive Assays to Probabilistic Assessments: Differentiation of Shooters from Non-Shooter Using IMS, OGSR, Neural Networks, and Likelihood Ratios”. Forensic Sci. Int2016; 263: 176–185.
12.
AbregoZ.UgarteA.UncetaN.Fernandez-IslaA.GoicoleaM.A.BarrioR.J.“Unambiguous Characterization of Gunshot Residue Particles Using Scanning Laser Ablation and Inductively Coupled Plasma-Mass Spectrometry”. Anal. Chem2012; 84: 2402–2409.
13.
WoodsB.Paul KirkbrideK.LennardC.RobertsonJ.“Soil Examination for a Forensic Trace Evidence Laboratory – Part 2: Elemental Analysis”. Forensic Sci. Int2014; 245: 195–201.
14.
J.L. Gottfried, R.S. Harmon, A. LaPointe. “Progress in LIBS for Land Mine Detection”. Army Research Laboratory. 2010. ARL-TR-5127.
15.
FambroL.A.MillerE.T.VandenbosD.D.DockeryC.R.“Characterization of Lead-Free Gunshot Residue Analogs”. Anal. Methods2016; 8(15): 3132–3139.
16.
TarifaA.AlmirallJ.R.“Fast Detection and Characterization of Organic and Inorganic Gunshot Residues on the Hands of Suspects by CMV-GC-MS and LIBS”. Sci. Justice2015; 55: 168–175.
DockeryC.GoodeS.“Laser-Induced Breakdown Spectroscopy for the Detection of Gunshot Residues on the Hands of a Shooter”. Appl. Opt2003; 42(30): 6153–6158.
21.
DockeryC.TurnerJ.RosenbergM.B.KammardienerK.MungaiS.W.“Gunshot Residue Analysis in the Undergraduate Laboratory Using Toy Cap Guns”. Spectrosc. Lett2010; 43: 534–538.
22.
RosenbergM.DockeryC.“Determining the Lifetime of Detectable Amounts of Gunshot Residue on the Hands of a Shooter Using Laser-Induced Breakdown Spectroscopy”. Appl. Spectrosc2008; 62(11): 1238–1241.
GoodeS.DockeryC.R.BachmeyerM.F.NiewlandA.A.MorganS.L.“Detecting Gunshot Residue by Laser Induced Breakdown Spectroscopy”. Trends in Optics and Photonics2002; 81: 175–177.
25.
DockeryC.R.RosenbergM.B.KammerdienerK.McAdamsL.E.BruttoN.A.TurnerJ.ChowdhuryM.H.KiambuthiM.K.“The Occurrence of False Positive Tests for Gunshot Residue Based on Simulations of the Suspect's Occupation”. Journal of Undergraduate Chemistry Research2011; 10: 107–110.
26.
PicardR.CookD.“Cross-Validation of Regression Models”. J. Am. Stat. Assoc1984; 79(387): 575–583.
27.
HoggS.R.HunterB.C.Waddell SmithR.“Elemental Characterization and Discrimination of Non-toxic Ammunition Using Scanning Electron Microscopy with Energy Dispersive X-Ray Analysis and Principal Components Analysis”. J. Forensic Sci2016; 61(1): 35–42.
28.
OommenZ.PierceS.“Lead-Free Primer Residues: A Qualitative Characterization of Winchester WinClean™, Remington/UMC LeadLess™, Federal BallistiClean™, and Speer Lawman CleanFire™ Handgun Ammunition”. J. Forensic Sci2006; 51(3): 509–519.
29.
HoS.K.“A Minimally Destructive Multi-Element Sensing Technique for Metal Alloys by Laser-Induced Breakdown Spectroscopy”. Jpn. J. Appl. Phys2012; 51(8): 2401–2406.
30.
HarmonR.S.DeLuciaF.C.McManusC.E.McMillanN.J.JenkinsT.F.WalshM.E.MiziolekA.“Laser-Induced Breakdown Spectroscopy – An Emerging Chemical Sensor Technology for Real-Time Field-Portable, Geochemical, Mineralogical, and Environmental Applications”. Appl. Geochem2006; 21(5): 730–747.
31.
XuX.KoebergM.KuijpersC.KokE.“Development and Validation of Highly Selective Screening and Confirmatory Methods for the Qualitative Forensic Analysis of Organic Explosive Compounds with High Performance Liquid Chromatography Coupled With (Photodiode Array And) LTQ Ion Trap/Orbitrap Mass Spectrometric Detections (HPLC-(PDA)-LTQOrbitrap)”. Sci. Justice2014; 54(1): 3–21.
32.
L.A. Fambro. Lead-Free Gunshot Residues as Forensic Evidence. [Master of Science in Chemical Science Dissertation]. Kennesaw, GA: Kennesaw State University, 2016.
