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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: magnetic111 on March 28, 2012, 10:07:34 AM

Title: What is the difference bewteen silica and sephadex column chromatography
Post by: magnetic111 on March 28, 2012, 10:07:34 AM

Im not sure when I should be using sephadex column chromatography or silica gel column chromatography to separate compounds?

Title: Re: What is the difference bewteen silica and sephadex column chromatography
Post by: Babcock_Hall on March 28, 2012, 10:36:12 AM

Silica gel chromatography separates molecules based on their relative attraction to silica, which is generally greater for more polar molecules than for less polar molecules.  Sephadex is often used to separate molecules (especially biomolecules) on the basis of size.

Title: Re: What is the difference bewteen silica and sephadex column chromatography
Post by: Babcock_Hall on March 28, 2012, 06:50:16 PM

What are you trying to separate?  It would be easier to figure out the best strategy with a specific case.

Title: Re: What is the difference bewteen silica and sephadex column chromatography
Post by: magnetic111 on March 29, 2012, 06:32:56 PM

We weren't given a specific sample to separate.  It is a question put to us by our lecturer...

Title: Re: What is the difference bewteen silica and sephadex column chromatography
Post by: Arkcon on March 29, 2012, 09:43:40 PM

Then can you use the information already given to you by Babcock_Hall: to create a sample for each type of column?  Pick two compounds that are separate-able based on the chemical interactions mentioned.  This would be a great way to prepare for an upcoming exam, you can use your custom made examples in a definition.