1. Chemsheets AS006 (Electron arrangement)
21/11/2017
CHROMATOGRAPHY
© A Jul-16

2. Type Stationary Phase Mobile Phase
Column
Powder (SiO2 or Al2O3)
solvent
Paper
(simple TLC)
Absorbent paper
TLC
Powder (SiO2 or Al2O3) on glass/plastic plate
Gas
Powder (SiO2 or Al2O3) (sometimes coated with liquid)
Inert gas (e.g. Ar, N2)
© A Jul-16

3. In ALL chromatography
Substances separated according to relative affinity (attraction) to stationary and mobile phase.
If stronger affinity for mobile phase, then move quickly
If stronger affinity for stationary phase, the move slowly
© A Jul-16

4. Non-polar solvents: alkanes Polar solvents: water, alcohols
STATIONARY PHASE:
SiO2 (silica) and Al2O3 (alumina) are regarded as a polar powder (due to the nature of their surface structure)
MOBILE PHASE:
Non-polar solvents: alkanes
Polar solvents: water, alcohols
e.g. hexane as solvent on silica
non-polar molecules would move quickly
polar molecules would move slowly
© A Jul-16

5. Chemsheets AS006 (Electron arrangement)
21/11/2017
THIN LAYER CHROMATOGRAPHY
TLC
© A Jul-16

6. Stationary:
Powder (SiO2 or Al2O3)
Mobile:
Solvent

7. For colourless samples:
View results under UV light

8. can be stained using ninhydrin
Amino acids
can be stained using ninhydrin

9. solvent front For substance R Rf = 3 = 0.6 5 cm 5
For substance S Rf = 4 = 0.8
4 cm
3 cm
starting line
R S
© A Jul-16

10. Chemsheets AS006 (Electron arrangement)
21/11/2017
COLUMN CHROMATOGRAPHY
© A Jul-16

11. “Large scale TLC”
Stationary:
Powder (SiO2 or Al2O3)
Mobile:
Solvent

12. FROM: http://www.mun.ca/biology/scarr/4241_RCMchromatogrpahy.jpg

13. FROM: wikipedia

14. Chemsheets AS006 (Electron arrangement)
21/11/2017
GAS CHROMATOGRAPHY GC
© A Jul-16

15. Long coiled tube packed with powder.
Inert gas passes through tube
Retention time = time to travel through tube
Samples often analysed by mass spectrometer as they leave tube

16. Gas chromatogram (e.g. of a fraction of crude oil)