1. Do you have what it takes?
Forensics
Do you have what it takes?

2. What are we allowed to bring?
Test tubes & test tube holders
Droppers
Item for scooping (spatula/ micro-spatula), spoons, stir rods
pH paper or litmus paper
9-volt conductivity tester (NO AC testers allowed!)
Hand lens
Thermometer
Funnel & filter paper - Microscope slides and cover slips
Flame test equip. (e.g. nichrome wire, cobalt blue glass)
Metal tongs
Writing instruments (pen or pencil)
Pencil & ruler for chromatograms
x11” sheet of notes (2-sided)
Non-programmable calculator
Paper towels

3. Approved Safety Goggles

4. Unacceptable Goggles

5. Instruments for Testing

6. TI-84 Silver Ed. w/ Temperature Probe TI-84 Silver Ed. w/ pH Probe

7. Qualitative Analysis Use a flow chart for solids separation
Easier for students to follow

8. NaC2H3O2, NaCl, NaHCO3, Na2CO3, LiCl, KCl, Ca(NO3)2, CaSO4, CaCO3, Cornstarch, Glucose, Sucrose, MgSO4, H3BO3, NH4Cl
Add Water
CaSO4, CaCO3, Cornstarch
NaC2H3O2, NaCl, NaHCO3, Na2CO3 , LiCl, KCl, Ca(NO3)2, Glucose, Sucrose, MgSO4, H3BO3, NH4Cl
Insoluble
Soluble
pH paper
Acid
Strong Base
Weak Base
No Reaction
NH4Cl, H3BO3
Na2CO3
NaC2H3O2,
NaCl, LiCl, KCl, Ca(NO3)2
NaHCO3
MgSO4, Glucose, Sucrose
Add NaOH
Optional
NH4Cl
H3BO3
NH3 odor
No odor
Add HCl
Flame Test
CaCO3
CaSO4
Cornstarch
Bubbles
Sol'n above
Cloudy,
solid clarifies
Gelatinous
NaC2H3O2
KCl
Ca(NO3)2
LiCl
NaCl, MgSO4
Glucose, Sucrose
Lavender
Orange
Red
Yellow
Yellow,
Purple
Burned
MgSO4
NaCl, Glucose, Sucrose
Translucent
No reaction
precipitate
Add Benedicts
NaCl, Sucrose
Glucose
Add Hot Water
NaCl
Sucrose
Low solubility
High solubility

9. Plastics Flow Scheme

10. Polymer Testing
Cat Dog Human

11. Paper Chromatography

13. Thin Layer Chromatography (TLC)

14. Thin Layer Chromatography (TLC)

15. How to Calculate Rf’s Rf = distance component travels
distance the solvent traveled
Shaefer Ink
# Components
Rf Values
solvent front = 46mm
1 = 13mm
0.28
2 = 28mm
0.61
3 = 35mm
0.76
4 = 39mm
0.85
5 = 46mm
1.00

16. Mass Spectra

17. First bond cleavage yields a methyl cation :
CH3+ + ·CH2CH2CH m/e = 15
Second bond cleavage yields an ethyl cation :
CH3CH2+ + ·CH2CH m/e = 29
Third bond cleavage yields a propyl cation :
CH3CH2CH2+ + ·CH m/e = 43

18. Crime Scene Evidence - Fingerprints
Loop Twinned Loop Central Pocket Lateral Pocket Loop Loop
Arch
Tented Arch
Whorl
Composite
Accidental

19. DNA
CAGGATAGACTGAAT
GTCCTATCTGACTTAA
ATTCATAGACT
TAAGTATCTGA

20. Glass Analysis

21. Entomology
Basically the study of various bug life cycles with respect to a corpse time of death, temperature, surroundings, etc.
Two excellent references are:
by Dr. J.H. Byrd
by Dr. Stephen Bullington
Especially look at the photos of the cycle for BLOWFLIES!

22. Spatters

23. Seeds & Pollen

24. Shoeprints

25. Tire Treads

27. Blood The ABO Blood Group System
Group A – has only the A antigen on red cells (and B antibody in the plasma)
Group B – has only the B antigen on red cells (and A antibody in the plasma)
Group AB – has both A and B antigens on red cells (but neither A nor B antibody in the plasma)
Group O – has neither A nor B antigens on red cells (but both A and B antibody are in the plasma)

28. Donor Recipient O O A A B B AB AB

29. Caucasians
African American
Hispanic
Asian
O +
37%
47%
53%
39%
O - 8% 4% 1%
A +
33%
24%
29%
27%
A - 7% 2%
0.5%
B + 9%
18%
25%
B -
0.4%
AB + 3%
AB -
0.3%
0.2%
0.1%

30. Bullet Striations

31. Analysis Do all the pieces fit … ?

32. Percentages Qualitative Analysis = 20 % Polymer Testing = 20 %
Paper Chromatography = 15 %
Crime Scene Evidence = 15 %
Analysis (Overall) = 30 %
Total = 100 %

33. References Title Slide : world wide web Goggles : world wide web
TLC & Mass Spectra : Introduction to Organic Laboratory Techniques: A Small Scale Approach, 2nd ed., Pavia, Lampman, Kriz, & Engel, 2005, Thomson Brooks/Cole, pgs ,
DNA Slide :
Broken Glass : world wide web
Seeds & Pollen : world wide web
Blood ABO System :
Bullet Striations : world wide web &
All the Pieces Match : world wide web