What is it?
1
Chromatography
Separate mixture into components
Comparison to authentic samples
2
Spectroscopy
Identify components
3
Spectrometry
1
Infrared (IR) Spectroscopy
Identification of compounds
Based on molecular vibrations
Stretching and bending of chemical bonds
Energy change match that of IR light
2
Infrared (IR) Spectroscopy
Irradiate a molecule with IR
light of the correct frequency
Molecule starts to vibrate
3
Infrared (IR) Spectroscopy
Stretching frequency depends on
1
Masses of atoms involved
2
Stiffness of the bond
Single Double Triple
bonds bonds bonds
4
Infrared (IR) Spectroscopy
Double
bonds (stiff)
bonds to
H (light)
Triple bonds
(very stiff)
5
Infrared (IR) Spectroscopy
1500 cm-1
Characteristic of the
class of compounds
6
Infrared (IR) Spectroscopy
1500 cm-1
Characteristic of the
individual compound
7
Infrared (IR) Spectroscopy
1500 cm-1
Molecular
fingerprint
8
IR spectrum of diamorphine
Diamorphine
Diagnostic
 Fingerprint
region
9