CO' 177ppm
Cab 46 ppm
Ca 56 ppm
The Cab90 and C' difference: 177ppm-46ppm=131ppm
for 500 MHz AMX
131ppm * 12.5721Hz=1646.9451Hz
small angle shift is base on the following equation:
shift(degree)/Dt=360*1646.9451Hz=592900.24
The powers that Bax using:
pwr of 90Cab=4.43kHz t90=1/4*4.43kHz=56.4us
pwr of 180Cab=11.4 t180=1/2*11.4kHz=43.86us
pwr of 180Ca=10.6kHz t180=1/210.6=47.17us
One of the frequency shift pulse occurs when C(ab)
centered at 46 ppm. If I don't change power then
Using 32 step shift and 43.86us for 180 then Dt=43.86/32=1.67 usec.
Is this too short.?
Using 16 steps Dt=3.34us
Small angle shift = 3.34us*592900.24=1.98 degree. Is can be done on the Bruker
without problem like certain delay requirement often occurred in the modern
NMR machine. Any comments ?
Dr. Sheng Zhong
Dept. of Biochem. and Biophys.
UNC at Chapel Hill
sheng@hasty@med.unc.edu