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Analysis of Gunshot Residue By X-Ray Fluorescence, Raman Spectroscopy, and Inductively Coupled Plasma

Analysis of Gunshot Residue By X-Ray Fluorescence, Raman Spectroscopy, and Inductively Coupled Plasma. Delaney Caudill Courtney Belanger. Background. Gunshot Residue (GSR) is a type of physical trace evidence that is released when a gun is fired

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Analysis of Gunshot Residue By X-Ray Fluorescence, Raman Spectroscopy, and Inductively Coupled Plasma

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  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

  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 • 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

  10. Results: XRF

  11. Results: ICP Sample Calculation: Ex. .22 Caliber/ Barium 8688.5=556.28x-220.9 x=19.58 ppm

  12. ICP Calibration Curves

  13. 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!

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