Page 108 - Phytochemistry 2 (06-PG 605)

1-Adsorption chromatography (SC)

The stationary phase is a solid having adsorptive power (has
active adsorption sites on its surface)
The mobile phase is a liquid (LSC) or gas (GSC)
Used in TLC, column (gravity, GC & HPLC)

Forces involved in adsorption chromatography:
A)- Force attracting solute (neutral compound) to adsorbent
B)-Force tending to remove solute from the adsorbent

If polarity of mobile phase is changed in column (gradient elution)
If constant polarity (isocratic elution)

Adsorbents
1-Silica gel:

o Silica gel G
o Silica gel GF254 (gypsum "CaCO3" & fluorescein)
o Silica gel H (with no binder)
o Silica gel HR (extra pure)
2- Alumina: Al2O3
Alkaline alumina (PH 9-10), neutral (PH 7.5)
3- Magnesium or calcium silicates, magnesium oxide,
activated charcoal (carbon)

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