Thanks to all who responded to my e-mail. The problem turned to be due to
the MCI board in the Aspect. It is possible that phase shifting needed for
waltz16 was not actually done with the faulty board, hence residual
splittings in 13C{1H} spectra.
Abil
On Fri, 18 May 2001, Abil Aliev wrote:
> Date: Fri, 18 May 2001 18:36:48 +0100 (BST)
> From: Abil Aliev <uccaaea_at_ucl.ac.uk>
> To: ammrl_at_wwitch.unl.edu
> Subject: decoupling problem, AMX400
>
>
> 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
>
>
>
>
==============================================================
Dr Abil E Aliev
Department of Chemistry ** Telephone: 020 7679 4616 / 4644
University College London ** Fax: 020 7679 7463
20 Gordon Street ** E-mail: A.E.Aliev_at_ucl.ac.uk
London WC1H 0AJ **
Received on Mon May 21 2001 - 11:57:22 MST