rob harvey nate birth. when the physical markings of a fired bullet recovered from a crime scene...
TRANSCRIPT
![Page 1: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/1.jpg)
Comparative Bullet Lead and Antimony Analysis using XRF
and ICP-OESRob Harvey
Nate Birth
![Page 2: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/2.jpg)
When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm used in the crime is not recovered, the bullet can be compared with other bullets associated with a suspect by its elemental composition (Peters, 2002)
Background
![Page 3: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/3.jpg)
During the manufacturing processes, thousands of lead specimens (bullets and bullet cores) are produced with analytically indistinguishable compositions. However, those lead specimens that share the same composition are generally packaged within the same box of cartridges, or in boxes of cartridges of the same caliber and type at the same manufacturing plant, on or about the same date (Peters, 2002)
Background
![Page 4: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/4.jpg)
In one research effort, the group acquired and analyzed samples from bullet lead manufacturers. The results of these analyses confirmed that a cast billet poured from a pot of molten lead is relatively homogeneous, but that leads poured from separate molten batches are distinguishable. As a result, comparative bullet lead analysis has been adopted by laboratories and accepted by courts internationally (Peters, 2002)
Background
![Page 5: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/5.jpg)
Compositional bullet lead comparisons are possible because each melt of lead has its own characteristic composition (Peters, 2002)
Also backed by a study in 2005 by Koons and Buscaqlia◦ Looked at 1837 samples, determined that 76% of
them can be distinguished from one another
Significance
![Page 6: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/6.jpg)
"The bullet removed from the victim and 10 of the 15 analyzed cartridges from the suspect residence are analytically indistinguishable from one another. Therefore, they likely originated from the same manufacturer's source (melt) of lead.” (Peters, 2002)
This conclusion does not associate a bullet to a box but rather to a melt of lead that has bullet specimens within that box and perhaps other boxes.
Quote from FBI
![Page 7: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/7.jpg)
Methods
![Page 8: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/8.jpg)
Flowchart4 Bullet Samples
Run in XRF
Dissolve Bullets
Run in ICP-OES
Compare Bullets
![Page 9: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/9.jpg)
Bullet 1◦ Fired, Smashed, Full Metal Jacket
Bullet 2◦ Unfired, Hollow Point
Bullet 3◦ Unfired, Standard
Bullet 4◦ Unfired, Standard
Bullet Samples
![Page 10: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/10.jpg)
XRF works by exciting the sample
Reads the unique X-rays given off
Gives percentage amount of metals
Bullets ran, and the resulting table printed
XRF Runs
![Page 11: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/11.jpg)
Concentrated Nitric Acid was used
Bullets were cut with a hack saw
Shavings were weighed as close to 1.00 g as possible
The bullets sat in the acid for a week
Bullet Dissolving Method
![Page 12: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/12.jpg)
Standards were made for both lead and antimony for 10, 20, 30, 40, 50, 75, 100, and 500 ppm
Samples spiked with 2 ppm of both metals, before dilution, after dilution, value is 0.20 ppm
The bullet/acid solution was diluted to 50 ml with a volumetric flask, and then later to 500 ml
Standards were ran to make a calibration curve Samples were ran to plot on the curve
ICP-OES
![Page 13: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/13.jpg)
To get total ppm of the dissolve bullet: To make standard solutions: Experimental values were calculated using
the linear regression equation
Percent Composition from ICP:
Calculations
![Page 14: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/14.jpg)
Results
![Page 15: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/15.jpg)
XRF Data
![Page 16: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/16.jpg)
ICP Calibration Curve Table
![Page 17: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/17.jpg)
![Page 18: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/18.jpg)
![Page 19: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/19.jpg)
Bullet 1 – 2136 ppm
Bullet 2 – 2004 ppm
Bullet 3 – 2000 ppm
Bullet 4 – 2014 ppm
Bullet ppm Levels
![Page 20: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/20.jpg)
Bullet 1 – 150.8 ppm
Bullet 2 – 1391.0 ppm
Bullet 3 – 1077.3 ppm
Bullet 4 – 385.5 ppm
Experimental Lead Levels
![Page 21: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/21.jpg)
Bullet 1 – 0 ppm
Bullet 2 – 1.26 ppm
Bullet 3 – 0.016 ppm
Bullet 4 – 6.83 ppm
Experimental Antimony Levels
![Page 22: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/22.jpg)
Summary Table
![Page 23: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/23.jpg)
Discussion
![Page 24: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/24.jpg)
Used the XRF and ICP-OES to look at bullet composition
XRF provided a fast accurate analysis ICP-OES was able to detect lower levels of
analytes◦ Detected antimony in all samples but 1, XRF only
found 2 bullets with antimony Bullet Dissolving process could be changed
Evaluation of Method
![Page 25: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/25.jpg)
Dissolving process◦ Not everything dissolved, longer sonication could
result in more material dissolving◦ Place watch glass on top of beaker
ICP Runs◦ Concentration of the bullets was higher then
expected, not enough dilution was done Calculating ppm and percent composition
◦ Account for the fact that not all the mass measured was dissolved, lead to percents from ICP to be low
Issues to be Addressed
![Page 26: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/26.jpg)
Concept that different bullets have different compositions was shown◦ XRF data and ICP-OES data both shows this
Lead varied among the bullets, but was always the most prevalent
Antimony was found in all bullets but one, so it could be a good analyte to look for
Comparison of Bullets
![Page 27: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/27.jpg)
Increase Sample Size
Compare different brands
Compare different types
Look at different metals
Future Studies
![Page 28: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/28.jpg)
Project showed that the levels of lead and antimony vary between bullets
Method is fairly straightforward and solid◦ Has kinks that need to be worked out
Issue of using a watch glass to minimize evaporation, diluting the sample enough, and accounting for undissolved mass
With the few issues resolved this method can be used to help possibly identify bullets at crime scenes that have been too badly damaged for visual study
Overall
![Page 29: Rob Harvey Nate Birth. When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison or the firearm](https://reader030.vdocuments.mx/reader030/viewer/2022032709/56649ec85503460f94bd566c/html5/thumbnails/29.jpg)
Forensic significance of bullet lead compositions RD Koons and J. Buscaqlia Journal of Forensic Science 2005 50(2), 341-351
The Basis for Compositional Bullet Lead Comparisons Charles A. Peters Forensic Science Communications 2002 4(3)
Literature Cited