Hi tbuihuu:
The Stationary Phase Sephadex LH-20 is used for Size Exclusion Chromatography (SEC)
or for Column Chromatography. Is a semirigid gel obtained by hydroxipropylation of Sephadex G-25.
Normally is use with mobile-phase as Polar Organic Solvents, Alcohols, but also is compatible with water.
This Gel have Hydrophilic and Lipophilic properties.
Answer to your post:
The principle of mecanism of separation of compounds with this Stationary Phase is on the basis of difference in the size of the molecules.
Maybe influenced by:
+ molecular shape
+ functional groups
+ chain lengths,
+ degree of unsaturation
As well as the effect of the eluent on the elution pattern
Also, SEC is uniquely different from the other Liquid Chromatography Method in that it is a chromatographic processs controlled by entropy, no enthalpy
Please check on Google these terms:
- Gel Filtration chromatography
- Gel Permeation Chromatography
Also, I recommend you find into your Campus Library these books:
- Preparative Gel Chromatography on Sephadex LH-20 by H. Henke
- Modern Size-Exclusion liquid Chromatography by Yau, Kirkland and Bly
and check these links:
=>
http://en.wikipedia.org/wiki/Size_exclusion_chromatography=>
http://www.linfield.edu/chem/C440/Gel_filtration_chromatography.pdfRegards,
Chiralic