Forensic Chemistry

Question 1

What is forensic chemistry?

Answer 1

• The application of analytical techniques to identify and compare evidence
• The determination of the composition of evidence
• Involves physical and chemical analyses of materials

Question 2

What are some examples of Organic Compounds?

Answer 2

• Drugs - Alcohol, weed, heroin
• Synthetic fibres
• Petro products - gas
• Paint binders
• High grade explosives

Question 3

What are some examples of Inorganic Compounds?

Answer 3

• Tools and weapons
• Metal scrapings
• Pigments in paints and dyes
• Inorganics incorporated into explosives
• Inorganic poisons such as mercury, lead and arsenic

Question 4

What is Chromatography?

Answer 4

• The separation of components of a mixture based on differing attractions to a stationary phase, while propelled by a moving phase

Question 5

How can certain materials be differentiated from each other? (I know this is a vague question lol, just memorize the answer)

Answer 5

• Many manufactured products and most natural materials contain small quantities of elements present in low concentrations

Question 6

What are some analytical techniques designed to determine the elemental composition of materials?

Answer 6

• Emission spectroscopy
• Atomic absorption spectrophotometry
• X-Ray Diffraction

Question 7

What is Spectrophotometry?

Answer 7

• Method for identifying substances based on selective absorbance of different wavelengths of light

Question 8

What causes separation in chromatography?

Answer 8

• When certain molecules are more soluble that others, and therefore get pushed along a faster rate

Question 9

What is Emission Spectroscopy?

Answer 9

• Sample is vaporized and heated to high temperatures, atoms reach excitement, influx energy causes e- to jump to a higher energy state, e- cannot remain in that state for long, they fall back to original energy and release energy in the form of light

Question 10

What is HPLC?

Answer 10

• High Performance Liquid Chromatography. Where solid is stationary and liquid is moving phase.
• Used for temperature sensitive materials like explosives and LSD

Question 11

What is TLC?

Answer 11

Solid stationary phase and liquid mobile phase. This method is rapid, sensitive and low cost. Numerous samples can be done on one plate simultaneously

Question 12

How can Spectrophotometry used in Forensics?

Answer 12

• Chemical substance will absorb selective frequencies based on composition
• Absorbed frequencies are measurable and used to characterize material
• Absorption spectrum: Graph of absorption vs. Frequency

Question 13

What is Ultraviolet Spectrophotometry?

Answer 13

• Ultraviolet Spectrophotometry is the measurement and absorbance of UV radiation
• Excellent screening tool that can be used to quickly eliminate other compounds
• Useful in quantification