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Topic: Grease in NMR  (Read 15044 times)

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Offline gilgerto

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Grease in NMR
« on: May 05, 2008, 09:56:44 PM »
I often have grease in my 1H NMR (broad s 1.26 ppm and small m 0.86 ppm) of purified product when running a column on small amount of material (below 50mg). I'm doing everything I can to avoid it (gloves, use dist. hexanes, flushing column with eluant before chromatography...). Any comment on that???
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Offline agrobert

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Re: Grease in NMR
« Reply #1 on: May 05, 2008, 10:16:18 PM »
More likely from rotovap ground glass joints and/or not so "clean" NMR tubes.  Try cleaning your NMR tubes with hexanes, methanol, and acetone.  When you are running small samples these peaks tend to show up more.
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Offline gericox

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Re: Grease in NMR
« Reply #2 on: May 13, 2008, 04:32:44 PM »
Make a "blank" spectra with deutered solvent in your NMR tube to check absence grease and to be sure it's clean
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Offline Mitch

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Re: Grease in NMR
« Reply #3 on: May 13, 2008, 10:20:37 PM »
Doesn't grease come out at 0 more than 1.26 ppm?
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