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Topic: Column chromatography separation  (Read 7584 times)

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Offline Sheryl

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Column chromatography separation
« on: October 23, 2006, 07:59:01 PM »
The question asked is:  An orange compound was added to the top of a chromatography column.  Solvent was added immediately, and the entire column of solvent in the solvent reservoir turned orange.  No separation could be obtained from the chromatography experiment.  What went wrong?

Seems to me that the sample had not been properly adsorbed, did not establish a true equilibrium, and therefore washed through the column rather that separated.  The sample should be allowed to stand a short time before elution rather than putting the solvent in immediately.

Sound feasible?

Thanks from Sheryl

Offline movies

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Re: Column chromatography separation
« Reply #1 on: October 23, 2006, 09:57:05 PM »
Yeah, if your compound is very soluble in your eluent then you need to let it all soak down into the silica gel before you add solvent.  It's also sometimes a good idea to use a very non-polar solven when you first start adding solvent and then flush that down to the top of the silica again to make sure it won't dissolve up into the solvent reservoir.

Offline Sheryl

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Re: Column chromatography separation
« Reply #2 on: October 24, 2006, 12:46:23 PM »
Thank you.  Big help.

S

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