Page 103 - Phytochemistry 2 (06-PG 605)
P. 103
Chromatography
From the latin word khromatos, indicates color
https://youtu.be/SnbXQTTHGs4
Definition:
Separation process based on the distribution of mixture
components between two phases, one of which flow past the
other.
Stationary phase (immobile) & mobile phase (moving)
Each phase competes with the other for the mixture components
The components of the mixture will be distributed in the two
phases based on the distribution coefficients (capacity factor)
K' = ns/ nm
ns = total number of molecules in the st.ph.
nm = total number of molecules in the m.ph
The distribution coefficients depend on
physical properties of compounds: solubility, adsorption, ionic
charge of ionized substance, volatility, molecular size (molecular
weight).
Different compounds show different physical properties, even very
minute.
These differences cause the substances to move through the
system at different rates (differential migration), results in
chromatographic separation.
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