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Topic: Good stain for amides?  (Read 19929 times)

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Offline taurean

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Good stain for amides?
« on: January 10, 2008, 08:10:18 PM »
Guyz,

What is the good stain for TLCs?  Especially I am looking for staining amides.  Please let me know.  KMNO4 stain is not working for me.

Please suggest some good book or journal articles where I can find information about stains applicable for specific functional groups.

Thanks a lot.

Offline agrobert

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Re: Good stain for amides?
« Reply #1 on: January 10, 2008, 09:02:13 PM »
Depending on your amide ninhydrin is a great reagent.  It tests positive for primary and secondary amines and so heating your TLC plate can cause amide hydrolysis and result in positive tests.

http://en.wikipedia.org/wiki/Ninhydrin
In the realm of scientific observation, luck is only granted to those who are prepared. -Louis Pasteur

Offline taurean

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Re: Good stain for amides?
« Reply #2 on: January 10, 2008, 09:29:13 PM »
Depending on your amide ninhydrin is a great reagent.  It tests positive for primary and secondary amines and so heating your TLC plate can cause amide hydrolysis and result in positive tests.

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

I just tried Ninhydrin, it also did not work.  Please suggest some other stain.

Offline Rico

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Re: Good stain for amides?
« Reply #3 on: January 11, 2008, 02:32:56 AM »
Hey taurean

I've had good results with using PMA-dip (phosphomolybdic acid) for esters, maybe it will work for amides too.

Recipe for PMA-dip: dissolve 10 g of PMA in 100 ml of absolute ethanol.

I hope it will work for you.

Rico

Offline chiralic

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Re: Good stain for amides?
« Reply #4 on: January 11, 2008, 07:52:06 AM »
Hello everyone:

Read this where you can find several Staining solutions to TLC and comments:
http://orgprepdaily.wordpress.com/2006/09/27/tlc-staining-solutions/

Regards,

Chiralic

Offline taurean

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Re: Good stain for amides?
« Reply #5 on: January 11, 2008, 09:54:41 PM »
Hello everyone:

Read this where you can find several Staining solutions to TLC and comments:
http://orgprepdaily.wordpress.com/2006/09/27/tlc-staining-solutions/

Regards,

Chiralic

Thanks for the excellent link.

Offline taurean

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Re: Good stain for amides?
« Reply #6 on: January 11, 2008, 09:55:16 PM »
Hey taurean

I've had good results with using PMA-dip (phosphomolybdic acid) for esters, maybe it will work for amides too.

Recipe for PMA-dip: dissolve 10 g of PMA in 100 ml of absolute ethanol.

I hope it will work for you.

Rico

Thanks, Rico.  I will try it out.

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