The 13C pulse calibrations should be done in the inverse mode (13C through the 2nd channel) using the pulse sequence decp90 (see Tutorial: Pulse Calibrations) . For instance, a sample of 0.1 M CH3OH-13C in DMSO-d6. can be used. The 13C-offset for the methyl group in methanol is 49 ppm, the methyl 1H-offset is 3.28 ppm and the one-bond coupling constant is 142 Hz. The calibration affords an antiphase signal that its intensity depends on the flip angle of the selective 13C-pulse. When the 13C-pulse is a perfect 90-pulse, the magnetization is completely converted to a multiple quantum coherence and the obseved signal reaches its minimum.
The required pulses to be applied from the 13C or f2 channel are:
Band-selective 13C pulses to excite particular regions. This is an example of carbon pulses defined in edprosol:
