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Topic: Paper Chromatography...please help !  (Read 3549 times)

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Offline Jessie

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Paper Chromatography...please help !
« on: March 23, 2008, 12:55:20 PM »
To develop a chromatogram, why is it important that when you put the paper into a solvent( eg.water), the level of the developing water was not above the level of the applied ink? What effect would it have on the chromatogram development?

also, it takes ~12 h for the slowest moving pigment band to migrate to the top of the chromatogram paper. If the chromatogram was allowed to develop for 24 hours, describe the expected appearance of the ink sample at the top of the chromatography paper. Include reasoning.

please help  me with these two questions..thanks very much!!!

Offline ARGOS++

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Re: Paper Chromatography...please help !
« Reply #1 on: March 23, 2008, 01:20:26 PM »
Dear Jessy;

The answer for the first Question lies already in the second:
The “Elution Mixture”, or Water, transports something till to the top, but not all kinds with the same “Migration Speed”.
So what will be the consequence of that?

If you have answered the first Question:
What will be the “benefit” if also the slowest migratiting “Spot” reachs the “target” (the top)? 
For what in this case will you have done the whole work?,  ─   For Nothing!!

I hope the last will never happen to you, but I have been of help .

Good Luck!
                    ARGOS++

Offline Arkcon

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Re: Paper Chromatography...please help !
« Reply #2 on: March 23, 2008, 08:09:24 PM »
To develop a chromatogram, why is it important that when you put the paper into a solvent( eg.water), the level of the developing water was not above the level of the applied ink? What effect would it have on the chromatogram development?

Try it and see.  Seriously, apply water soluble ink to paper and submerge in water.  Do you really have to ask the forum what will happen?

Quote
also, it takes ~12 h for the slowest moving pigment band to migrate to the top of the chromatogram paper. If the chromatogram was allowed to develop for 24 hours, describe the expected appearance of the ink sample at the top of the chromatography paper. Include reasoning.

No guess at all?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

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