[tbuihuu]

i usually use its but i don't known about mechanism of it. please help me, thanks!

[Dan]

http://en.wikipedia.org/wiki/Column_chromatography

[chiralic]

Hello tbuihuu:

Are we talking about Sephadex LH-20? The mechanism for this sp

Regards

Chiralic

[tbuihuu]

@: Chiralic. Yes, do you know about that? how does it work?

[mdlhvn]

try these pages

http://en.wikipedia.org/wiki/Sephadex
http://en.wikipedia.org/wiki/Dextran

Can you tell more details about the usage of it. I mean how you use it, for what purposes?

[chiralic]

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.pdf

Regards,

Chiralic