Your SlideShare is downloading. ×
0
Forensic toxicology & chemical evidence
Forensic toxicology & chemical evidence
Forensic toxicology & chemical evidence
Forensic toxicology & chemical evidence
Forensic toxicology & chemical evidence
Forensic toxicology & chemical evidence
Forensic toxicology & chemical evidence
Forensic toxicology & chemical evidence
Forensic toxicology & chemical evidence
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Forensic toxicology & chemical evidence

2,587

Published on

Published in: Technology, Business
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
2,587
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
120
Comments
0
Likes
1
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Forensic Toxicology & Chemical Evidence
  • 2. Forensic Toxicologist identifies and analyzes poisons, drugs, and chemicals studies the effect of such substances on the body Important in helping medical examiner determine cause of death in an autopsy all the blood and tissue samples undergo a toxicology screening.
  • 3. Toxicology Tests: Chromatography – separate and quantify individual chemical compounds  Mobile phase – substance is dissolved in solvent  Stationary phase – dissolved substance is passed through a finely divided adsorbent, different compounds move at different speeds, rates of adsorption are plotted on a chart.
  • 4. Toxicology Tests: Thin-Layer Chromatography (TLC) –  uses a glass or plastic plate covered with a thin layer of finely ground adsorbent such as silica gel or alumina  sample is deposited on the plate  locations of separated components are noted after the solvent evaporates
  • 5. Toxicology Tests: Gas Chromatography – separates liquids and gases  material is coated on fine clay or glass beads and packed into a steel or copper column  column is heated above boiling point of liquid  gas pushes compounds through column  detectors measure emerging fractions
  • 6. Toxicology Tests:Mass Spectrometry – identifies the chemical structure of an unknown substance  after separating a substance using gas chromatography each component enters a vacuum chamber  the components collide with a beam of high-energy electrons causing the component molecules to lose electrons and become charged ions  they then pass through a magnetic or electric field where they are separated according to their masses and can be identified
  • 7. Toxicology Tests:Spectrophotometry - measures how much radiation from the electromagnetic spectrum is absorbed by a particular chemical
  • 8. At the Crime Scene Crime scene technicians can  Fire accelerants conduct field tests  Blood that detect many  Explosives chemical residues  Gunshot residue found at crime  Drugs scenes, in  Cosmetic material vehicles, or on  Construction material clothing  Trace metals
  • 9. Types of chemical evidence Solids – poisons, drugs, soil, cement, minerals, explo sive residues, gunshot residues, cosmetics, trace materials Liquids – acids, gasoline, body fluids, beverages, chemicals for drug labs, cleaning fluids, medications, poisons Gases – natural gases, refrigerants, butane, propane, tear gas, propellants

×