Chemistry Workshop Forensic Investigation Roanoke College November 21, 2005

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Chemistry WorkshopForensic InvestigationRoanoke
CollegeNovember 21, 2005
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Jess welcomes the President and Gives her a cold
bottle of water.
I Wonder
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Yummy! Mmmm, quite an unusal taste for water.
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Uh-oh whats happened?
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The Crime Scene
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Was it the water.?
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whose hair..?
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A poisonous spider?
A poisonous
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The Suspects
The Suspects
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No scholarship for me!X !!!! President OHara
watch out for me. Jason takes revenge!!
Suspect 1 Jason
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I love trying out different poisons on things.
Looks are deceiving. Is Peggy really all that
sweet and innocent?
Suspect 2 Peggy
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Suspect 3 Jess
Aha, this will work.
Whats going on? Is Jess helping with lab or
mixing up a special brew for someone?
Suspect 3 Kimberly
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Suspected Black Widow
Va. Police Criminal Files
112358
Suspect 4 Becca
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Whos next? He, He, He
Suspect 5 Dr. Gary Hollis AKA The Nutty
Professor
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NMR Analysis
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Using the NMR to Analyze the poison.
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Total of 10 carbon environments (atoms) in
molecule
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Of these 10 carbon atoms, one is a CH3, two are
CH2, four are CH, and three have no hydrogens.
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Aromatic Alkene Alcohol Alkene
Methyl on O Methylene
1-CH 2-CH 1-CH 1-H on O 1-CH2
1-CH3 1-CH2
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Infrared Analysis
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Dr. Hollis helps with the IR analysis.
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O-H C-H Aromatic?
(alkene)
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GC- MS Analysis
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The Poison Compound

• Eugenol

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Building a model of Eugenol, found in cloves.
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Eugenol model
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DNA ANAlYSIS
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Electrophoresis gel preparation
Preparing for electrophoresis.
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DNA Deoxyribonucelic acid

• Genetic material
• blue-print for all proteins
• Unique for every individual (except identical
  twins)

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DNA Structure

• Backbone of alternating phosphate and sugar
  residues
• Sides of the ladder
• Note Negative charge (anionic characteristic)
• Bases extend from the backbone
• Rungs of the ladder
• 4 bases A, T, C, G
• Bases pair across rungs AT, GC
• Sequence of bases unique code

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Restriction Endonucleases

• Cut DNA at specific sequences
• Numerous different restriction endonucleases

• Recognize palandromic sequences
• Read the same in opposite directions on adjacent
  strands

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Restriction Endonucleases

• Cut DNA into fragments
• Depending on the individual, the size of the
  fragments vary
• Separate fragments by size using electrophoresis

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Electrophoresis

• Place anionic (negatively charged) molecules in
  an electric field
• Molecules move through an agarose mesh towards
  the pole
• Smaller fragments travel farthest (least
  resistance VIR)

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DNA Fingerprinting

• DNA evidence only states that the suspect was
  PRESENT at the crime scene
• It does NOT definitively say one is guilty of not
  guilty
• It only provides an additional piece of evidence
  that a person was present at the scene of the
  crime

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Conclusion
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Guilty, Guilty, Guilty
Suspect 3 Motive yes DNA match
yes Opportunity yes
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The Chemistry Department thanks you for coming to
our exploration day.