Thread: Question from NMRWiki Q&A forum 15N 90 degree hard pulse calibration
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Unread 08-19-2014, 11:21 AM
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Default 15N 90 degree hard pulse calibration
15N 90 degree hard pulse calibration

Greetings, I want to ask for some advice in matter of 15N hard pulse calibration on Bruker machines. I'm working on Avance DRX 500 with 5mm TBI probe. This calibration is easy to made if 15N urea is avaible, but I don't have opportunity to use this compound. I have in my stable horses as follows:

methylamine hydrochloride (99% 15N) ammonium chloride (99,9% 15N) aniline (15N >99%) sodium nitrite (99% 15N)

I tried to use first two salts in DMSO-d6. Unfortunately I couldn't obtain proton spectrum with multiplet structure that is needed for pulse calibration (pulse sequence decp90), only broad peaks were visible ( protons attached to nitrogen directly). Aniline in Benzene also gave only broad signal. I tried to perform this calibration using 1D HSQC methodology but it also failed. (increasing pulse lenght in popt).

What am I doing wrong ? How can I calibrate this pulse without urea ?

Best regards, A. Leniak



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