1. Part 1: qualitative analysis
Chemical Analysis
Part 1: qualitative analysis

2. Chemical Analysis
One of the most important aspects of forensic science
Widely used in forensic analysis
Develop latent fingerprint
Obtain DNA
Analyze unknown substance
Identify drugs

3. Drug Identification Then instrumental analysis:
Use screening test first:
Thin-layer chromatography
Color test
Microcrystalline test
Then instrumental analysis:
Spectrophotometry
Mass spectrometry
Gas chromatography

4. Chromatography
The physical separation of a mixture into its individual components
Analyzing multi-component samples
Inks, dyes, drugs, and poisons, etc.

5. Examples of Chromatography
Liquid Chromatography
Thin-Layer Chromatography
(TLC)
Gas Chromatography
Paper Chromatography

6. Thin-Layer Chromatography TLC
Use a solid stationary phase and a moving liquid (mobile)phase to cause a separation of the components of a mixture
Solvent Front
Heroin
Quinine
Origin

7. Detect the colorless components separated from TLC
Exposing to UV light
Exposing to fluorescent dyes
Exposing to iodine
Spraying with a reagent

8. Rf (retention factor) value
Solvent finish 10 cm
Rf (retention factor) value
8 cm
The distance traveled by the component divided by the distance traveled by the solvent
It is usually expressed as a decimal
Identify components by comparing to known chemicals
Rf1 = 8/10 = 0.8
4 cm
Rf2 = 4/10 = 0.4
Starting point

9. Paper & Thin-layer Chromatography Tutorial
N05xXk

10. Color Test Initial screening for drugs
Color changes when certain chemicals present
Very simple and less expensive

11. Microcrystalline Test
More specific than color test
Specific chemical will form specific size and shape of crystal
Quick, cheap, and no isolation required
Copper Sulfate X 100