Considering quat carbons are often very sharp why not consider a bit of increase in 13C acquisition time? Not knowing the current choice for acq time I cannot say more. I tended to find many labs defaulting to stuff like 0.7 or 1 sec for 13C acq time while setting d1 around 1 sec. You may find that running the same rep rate but with longer acq time to actually better capture those sharp quats could help.
In my own lab I tended to use at least 1.5 sec acq time and d1 about 0.5. A simple approach might be to consider molecular weight and go longer for very small molecules and generally faster for large.
Sent with really tiny keyboard,
Ron
> On Mar 11, 2015, at 1:27 PM, Mark Swanson <mark94131_at_gmail.com> wrote:
>
> Hi Everyone,
>
> I would like to get a consensus for how long people typically set their D1 delay to detect quaternary and/or carbonyl carbons. Our default at 500 MHz is 1s for 13C and the quaternary/carbonyl carbons are often weak. I tell students they have to increase the D1 delay but I give them vague answers for exactly how long it should be, 5s, 10s, 30s, 1 min? Without measuring the T1s I don't have an exact answer to give them and "trial and error" tends to waste a lot of instrument time. Sorry if this seems trivial but I would be interested in knowing what my colleagues recommend.
>
> Thanks,
>
> Mark Swanson
>
Received on Thu Mar 12 2015 - 08:19:46 MST