I am working with carbohydrates and in 1D NMR we have anomeric protons very close to the HOD peak, sometimes even right under there. In the lab where I used to work we had a bruker machine with an adapted WEFT pulse (described by Hard et al, 1995), which basically does a 180 degree pulse on the HOD, followed by a HS pulse of 50 usec, d1 times to have 0 magnetization on HOD, then a detection pulse.
Since the HOD relaxes much slower than the glycan H-C protons you get about 80% signal on nearby glycan protons and your HOD is usually nearly gone. Glycan protons farther away from the HOD are at full signal strength (which is not so in the normal WEFT pulse described in 1972)
Where I work now, we have Varian machines with pre-installed PRESAT and WET1D pulses, however, these pulses do not only suppress the HOD signal, but also remove any carbohydrate signal that is near, or under, the HOD signal. Does anyone know of a way to adjust settings in the WET1D, which uses a shaped pulse for the HOD suppression much like the WEFT, to avoid the glycan signal suppression? Or do I have to try and get our old bruker pulse from my previous employer and try to translate it into Varian language?
