1.  Analysis of Gunshot Residue By X- Ray Fluorescence, Raman Spectroscopy, and Inductively Coupled Plasma Delaney Caudill Courtney Belanger

2. Background  Gunshot Residue (GSR) is a type of physical trace evidence that is released when a gun is fired  Analysis of GSR is an important technique in forensic science  It may place an individual at the scene of the crime  GSR is composed of inorganic and organic components

3. Significance and Purpose  To allow for nondestructive forensic analysis and detection  To detect GSR components using XRF and Raman  To quantify concentrations of GSR analytes using the ICP

4. Samples and Analytes InorganicOrganic IronEthyl Centralite Copper2-Nitrodiphenylamine Lead Barium Zinc Samples CaliberDistance.22< 3 feet.38< 3 feet.45< 3 feet Shotgun: 12 gauge4-5 feet

5. Method: XRF  Spiked sample was created  Solid reference and unknown samples were directly placed on XRF

6. Method: XRF  Soaked reference and unknown sample in 10 mL of 0.1 M nitric acid  Soaked for 48 hr  Pipetted 1 mL of solution into liquid sample holder for XRF

7. Method: Raman Samples Methyl ethyl Ketone (MEK solvent) Solid Ethyl Centralite Standard Solid 2-Nitrodiphenylamine Standard 100 mg of ethyl centralite in 0.5 mL of MEK 100 mg of 2-Nitrodiphenylamine in 0.5 mL of MEK.22 Caliber.38 Caliber.45 Caliber Shotgun: 12 gauge Soaked four unknown samples for 1.5 weeks in 10 mL of MEK

8. Method: ICP  Standards were created: 5, 10, 20, 30, 40 ppm  Unknown samples soaked for 2 weeks before analysis by ICP  Standards and unknown samples were run on ICP

9. Results: Raman Raman CompoundRelative Shifts (1/cm) Methyl Ethyl Ketone 2976.000, 2920.743, 1710.000, 1084.000, 759.000 Ethyl Centralite 2971.981, 3063.748, 2933.020, 705.528,428.901, 1455.783 2-Nitrodiphenylamine1144.701, 1255.381, 204.184.22 Caliber 2978.795, 2920.972, 2735.317, 1712.384, 1084.200, 759.522.38 Caliber 2976.523, 2920.897, 2735.063, 1709.513, 1085.329, 759.961.45 Caliber 2978.502, 2920.782, 2737.978, 1711.065, 1083.950, 760.048, 585.511, 408.906 Shotgun (12 Gauge) 2977.995, 2920.835, 2733.644, 1709.547, 1084.542, 759.548, 405. 193

10. Results: XRF Solid Cloth Sample (% Composition) AnalyteBariumCopperIronLeadZinc.22 caliber9.8301.6211.35664.0440.496.38 caliberN/A1.8361.7393.269N/A.45 Caliber12.99011.3370.55317.0531.644 ShotgunN/A1.8762.31710.201N/A Liquid Sample (% Composition) AnalyteBariumCopperIronLeadZinc.22 caliberN/A18.201N/A.38 caliberN/A13.936N/A.45 CaliberN/A15.754N/A ShotgunN/A7.724N/A

11. Results: ICP Concentration [ppm] AnalyteBariumCopperIronLeadZinc.22 caliber19.613.620.120.815.6.38 caliber1346.670.3640.0958.748.5.45 caliber856.759.2516.9654.228.8 Shotgun1153.063.91023.91740.444.9 Sample Calculation: Ex..22 Caliber/ Barium 8688.5=556.28x-220.9 x=19.58 ppm

12. ICP Calibration Curves

14. Discussion  Raman did not conclusively identify analytes May have needed more time to soak Could have been overwhelmed by solvent  XRF was able to detect each analyte of interest within solid method. At relatively similar distances, there seems to be no correlation between caliber size and percent composition

15. Discussion  XRF was only able to detect a percent composition of copper within liquid method May need to be soaked for longer to detect other analytes  ICP successfully quantified analytes of interest Generally, the.38 caliber had the highest concentration for each analyte when compared to the 3 calibers but had no correlation with the shotgun

16. References  Bueno, J; Sikirzhytski, V; Lednev, I. Raman Spectroscopic Analysis of Gunshot Residue Offering Great Potential for Caliber Differentiation. Analytical Chem. [Online] 2011, 1021, A-F  Lopez-Lopez, M; Delgado, J. J; Garcia-Ruiz, C. Ammunition Identification by Means of the Organic Analysis of Gunshot Residues Using Raman Spectroscopy. Analytical Chem. [Online] 2012, 1021, A-D

17. Special Thanks  Matt Cunningham for providing GSR samples  Dr. Foy for letting us play with really expensive instruments  Our lab assistants: Kiersten and Pat L.  Professor Mowery for ordering our chemicals Look at that center burst!