i like this post (click again to cancel)
i dont like this post (click again to cancel) remove favorite mark from this question (click again to restore mark)

hi, though this question seems to be easy for you but i am new for this software and to this field. Recently, i took silicon spectra in 500mhz(bruker) seems to be good (i.e.one silicon peak and one nmr tubes broad peak) but when i used same parameters for another sample where i got single peak as i expected but nmr tube peak is inverse this time. I just copied previous parameters only why i got such a inverse signal.If anybody know please help me.

thank you

asked Mar 31 '11 at 04:59

Ganesh's gravatar image


2 Answers:
i like this answer (click again to cancel)
i dont like this answer (click again to cancel)

Silicon is a nucleus with a negative gyromagentic ratio. This means that decoupled peaks or peaks that experience a nOe can have opposite phase to peaks that do not have nOe. Were the experiments done with decoupling? Did you use the same phase or use automatic phase correction?


answered Apr 02 '11 at 10:12

Clemens%20Anklin's gravatar image

Clemens Anklin

sorry,for delay in reply. I used automatic phase correction and experiments done with decoupling. - Ganesh (Apr 24 '11 at 23:28)

i like this answer (click again to cancel)
i dont like this answer (click again to cancel)

Did you use the same NMR tube? And, is the Tube Peak shape is the same in both cases which can be acertained by phase correcting the spectra by 180 degress and comparing the two tube peaks. Does the two samples have the same chemical shift between the sample peak and tube peak? Is there a possibility of frequency dependent/second order phase corerction parameters being different for the two cases? What was the relaxation delay in both cases if multiple scans were used for better Signal to Noise ratio? Can you have a standard reference Silicon compound to verify the relative phases not leaving the comparison only to test sample and NMR tube itself?


answered Apr 03 '11 at 23:33

SankarampadiAravamudhan's gravatar image


Your answer
Please start posting your answer anonymously - your answer will be saved within the current session and published after you log in or create a new account. Please try to give a good answer, for discussions, please use comments and please do remember to vote (login to vote)
toggle preview

powered by CNPROG