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ANALYZING GUN SHOT RESIDUE USING
THE ICP AND AA
Colleen Justison and Shelby Bleile
Inductively Coupled Plasma
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).
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.
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 One Trial Two Trial Three
6 inches straight 6 inches straight 6 inches straight
6 inches angled 10°
6 inches angled 10°
6 inches angled 10°
12 inches straight
12 inches straight
12 inches straight
12 inches angled 10°
12 inches angled 10°
12 inches angled 10°
Setup
Before & After
ProcedureDay 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.
Procedure Day Three
Filtered the shirts. Using vacuum filtration setup we filtered the 24 samples.
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.
ProcedureDay 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.
Data: Calibration Curves
Data: Calibration Curves
T Shirt Samples Barium Conc. (ppm)
Lead Conc. (ppm)
6 in. straight Top-T1
1.3359 4.5473
6 in. straight bottom-T1
0.69785 4.1719
6 in. straight top- T2
1.2206 4.3365
6 in. straight bottom-T2
0.81385 5.4916
6 in. straight top-T3
1.34 9.3969
6 in. straight botton-T3
2.4792 26.187
6 in angle top-T1 0.77045 3.07856 in angle bottom-T1
0.5737 3.4544
6 in angle top-T2 5.667 35.226 in angle bottom-T2
3.3847 26.039
6 in angle top-T3 1.1268 4.02286 in angle bottom-T3
2.6256 10.753
ICP Data 6 inch Samples
ICP Data 12 inch Samples
T Shirt Samples Barium (ppm) Lead (ppm)12 in straight top-T1
0.85521 14.082
12 in straight bottom-T1
0.4921 7.4843
12 in straight top-T2
0.64699 2.5193
12 in straight bottom-T2
0.599 3.4504
12 in straight top-T3
0.88931 5.299
12 in straight bottom-T3
0.6678 8.8138
12 in angled top-T1 3.4639 6.39812 in angled bottom-T1
2.6992 10.61
12 in angled top-T2 0.62378 5.56312 in angled bottom-T2
2.355 12.137
12 in angled top-T3 3.9365 11.87312 in angled bottom-T3
0.50442 3.2191
AA Data- 6 inch Samples
Sample Lead (mg/mL)
Barium (mg/mL)
6 in. straight Top-T1
18.83 12.39
6 in. straight bottom-T1
20.87 15.73
6 in. straight top- T2
16.23 17.67
6 in. straight bottom-T2
22.22 17.17
6 in. straight top-T3
43.17 20.9
6 in. straight botton-T3
52.22 20.84
6 in angle top-T1 20.26 28.58
6 in angle bottom-T1
16.84 28.28
6 in angle top-T2 48.37 30.83
6 in angle bottom-T2
36.42 29.82
6 in angle top-T3 20.02 32.02
6 in angle bottom-T3
13.74 30.68
AA Data-12 inch Samples
Sample Lead (mg/mL)
Barium (mg/mL)
12 in straight top-T1 38.12 20.912 in straight bottom-T1
35.62 20.82
12 in straight top-T2 14.98 23.7912 in straight bottom-T2
15.28 24.7
12 in straight top-T3 24.44 26.212 in straight bottom-T3
44.93 26.41
12 in angled top-T1 15.18 31.8612 in angled bottom-T1
13.06 31.57
12 in angled top-T2 32.95 32.3812 in angled bottom-T2
16.12 33.51
12 in angled top-T3 14.89 35.5312 in angled bottom-T3
9.417 34.84
Conclusions
The gun shot residue contained more Lead then it did Barium.
We saw higher numbers from the AA because it has lower interference.
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
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
