ANALYZING GUN SHOT RESIDUE USING

THE ICP AND AAColleen Justison and Shelby Bleile

Atomic Absorption

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 28.586 in angle bottom-T1

16.84 28.28

6 in angle top-T2 48.37 30.836 in angle bottom-T2

36.42 29.82

6 in angle top-T3 20.02 32.026 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

AcknowledgementsThank 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