Hi all, I'm trying to remove some excessive bumps on the NMR spectrum of my compound. The compound is there but I receive some extra bumps that don't indicate the traces of the solvent (dried under rotovap, high vac-pump, and vacuum distillation for 3 overnights). I cleaned and dried my NMR tubes thoroughly and this has never happened before as I reused the same NMR tubes. When I ran a TLC analysis, I saw no extra spots of the compound. I ran an HPLC purity test (only one sharp peak) and LCMS test which indicated that the compound has been synthesized.
I use a 400 MHz NMR instrument and I ran more than one proton scans to see whether the bumps go away or not after multiple washes. I don't mind losing some of the compound's particle as the purity is far more important than the amount.
To be sure that the extra oeaks don't indicate that you are looking at a different compound than what you are thinking, I would first use mass spec to verify.
Good Luck
It seems to me that the reason for your unexplained peaks does not lie in impurities but in the settings of your spectrometer. Look at www2.chemistry.msu.edu under the heading „NMR Artifacts“. Very interesting and useful! You might find the explanation of your problem there.
Good luck!
Ludger
The reasons could be quite numerous - from improper sample preparation to poor instrument conditions and wrong acquisition parameters... This discussion will remain mostly speculative without knowing full details.
@Michiel Vanmeert Thank you for your response but I already used LCMS to do that and it indicated the presence of the compound.
@Vladimir Khlebnikov : Thanks but the instrument is updated regularly. Will check in with lab tech one more time soon.
@Ludger Ernst : Thanks for the resource. Will read it for further details.
Thank you all.
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