I would appreciate if anybody could help me in soft pulse programming.
My question is:
I want to select a single line within quadruple 1H-peaks, and I can do
it by using sinc soft pulse with duration=800ms, pl=97dB, with the peak
height about 3/4 of original, but when I cascade the soft pulse with
hard pulse or two soft pulses, the results are totally different from
what is expected from the pulse sequences. e.g when I apply soft
pulse+hard pulse, the peak height is nearly same as hard pulse, the
height of the quadruple peaks (not a single line)a little weaker than
hard pulse (by theory only 3 lines appear in this region); with hard
pulse+soft pulse the result is quite different, only small dispersive
peaks remained, even for peaks far from selected region, very strange,
as though soft pulse acted somewhat as hard pulse. Our machine is
DMX-500, and software is Xwinnmr-1.1. Anyone can tell me what is wrong ?
I have checked the phase difference between soft pulse and hard pulse.
Thanks,
Wu Jihui
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Wu Jihui email: wujihui@ustc.edu.cn
Tel. 0086-551-3603745 (NMR lab)
School of Life Science, Univ. of Science and Technology of China
Hefei, Anhui, 230026 P.R.of China