1. Colleen Justison and Shelby Bleile

2. Atomic Absorption

3. Inductively Coupled Plasma

4. Gun Shot Residue  Gun powder burns quickly to produce rapid expansion of gas  The three major elements are lead (Pb), barium (Ba), or antimony (Sb).

5. Purpose  The purpose of our experiment was to observe the residue left on a person that had been shot at two different distances and angles.  We used the AA and ICP to analyze the shirts and determine the amount of Barium and Lead found on them.

6. Procedure Day One  Cut t-shirts into “10x10” pieces.  Shot a 9 mm  Cut the shirts in half to give a total of 24 samples. Trial OneTrial TwoTrial Three 6 inches straight 6 inches angled 10° 12 inches straight 12 inches angled 10°

7. Setup

9. Before & After

10. Procedure Day Two  We made a 0.3 M solution of nitric acid from a 16 M solution.  Used to soak the t-shirts to remove the solid from the shirts and put it into solution.  Made standards of Lead and Barium. 1, 5, 10, 15, 20, 25 ppm.  Let the shirts soak in the acid for 24 hours.

12. Procedure Day Three  Filtered the shirts. Using vacuum filtration setup we filtered the 24 samples.

13. Prodecure Day four  Ran our standards and samples using the AA.  found that we needed to make higher concentrated standards because we had residue at higher ppm.  The new standards we made were 10, 20, 40, 60, and 80 ppm of Lead and Barium.

14. Procedure Day Four Cont.  We ran all 24 samples on both the ICP and AA.  We found that the ppm was greater on the AA then on the ICP.

15. Data: Calibration Curves

17. T Shirt Samples Barium Conc. (ppm) Lead Conc. (ppm) 6 in. straight Top-T11.33594.5473 6 in. straight bottom-T10.697854.1719 6 in. straight top- T21.22064.3365 6 in. straight bottom-T20.813855.4916 6 in. straight top-T31.349.3969 6 in. straight botton-T32.479226.187 6 in angle top-T10.770453.0785 6 in angle bottom-T10.57373.4544 6 in angle top-T25.66735.22 6 in angle bottom-T23.384726.039 6 in angle top-T31.12684.0228 6 in angle bottom-T32.625610.753 ICP Data 6 inch Samples

18. ICP Data 12 inch Samples T Shirt SamplesBarium (ppm)Lead (ppm) 12 in straight top-T10.8552114.082 12 in straight bottom-T10.49217.4843 12 in straight top-T20.646992.5193 12 in straight bottom-T20.5993.4504 12 in straight top-T30.889315.299 12 in straight bottom-T30.66788.8138 12 in angled top-T13.46396.398 12 in angled bottom-T12.699210.61 12 in angled top-T20.623785.563 12 in angled bottom-T22.35512.137 12 in angled top-T33.936511.873 12 in angled bottom-T30.504423.2191

19. AA Data- 6 inch Samples SampleLead (mg/mL)Barium (mg/mL) 6 in. straight Top-T118.8312.39 6 in. straight bottom-T120.8715.73 6 in. straight top- T216.2317.67 6 in. straight bottom-T222.2217.17 6 in. straight top-T343.1720.9 6 in. straight botton-T352.2220.84 6 in angle top-T120.2628.58 6 in angle bottom-T116.8428.28 6 in angle top-T248.3730.83 6 in angle bottom-T236.4229.82 6 in angle top-T320.0232.02 6 in angle bottom-T313.7430.68

20. AA Data-12 inch Samples SampleLead (mg/mL)Barium (mg/mL) 12 in straight top-T138.1220.9 12 in straight bottom-T135.6220.82 12 in straight top-T214.9823.79 12 in straight bottom-T215.2824.7 12 in straight top-T324.4426.2 12 in straight bottom-T344.9326.41 12 in angled top-T115.1831.86 12 in angled bottom-T113.0631.57 12 in angled top-T232.9532.38 12 in angled bottom-T216.1233.51 12 in angled top-T314.8935.53 12 in angled bottom-T39.41734.84

21. Conclusions  The gun shot residue contained more Lead then it did Barium.  We saw higher numbers from the AA because it has lower interference.

22. Future Work  Use different guns/bullets and test for metals  Test for Antimony as well as Lead and Barium  Shoot from more angles and distances  Use the XRF to observe the samples

23. Acknowledgements Thank you to Chris for making our lives a lot easier during this project and for Andrew for putting up with us all semester. Thank you to the Chemistry department for funding our experiment