We have a problem with 1H decoupling on our AMX400. Usually 25db/100us is
used by zgpg30 (cpd = walt16) to decouple from protons when observing 13C,
but lately it has not been sufficient: for 20%CHCl3 / Acetone-d6 about
80Hz residual coupling is still left. The 1H frequency o2 in this case is
approximately 1.5kHz off-resonance. If this is set on-resonance, splitting
disappears. We have checked both high- and low-power pulses using decp90,
these have not been affected. Have also tried garp and bb modes for cpd,
but splitting is still there.
Any suggestions are most welcome,
Abil
Received on Fri May 18 2001 - 18:01:46 MST