Sometimes people are interested in doing quantitative 13C NMR for various reason. One of the most common reason is that those signature proton chemical shift is not resolved from each other. Is quantitative 13C NMR doable? The answer is yes. But the common NMR that we teach can not be used for quantitative 13C NMR. For two reasons, NOE contributions typically is involved and not enough time for fully relaxation.
To resolve this issue, it is suggested that we rpar a different experiment in Bruker system, C13ig, and then getprosol and change a few parameters. Normally we suggest to minimize the sweep region to the carbon peaks of interest. This allows you to short the acquisition time using 2K data point (td=2k) while keep a good resolution and prevent NOE buildup during that time. The program utilize a 30 degree carbon pulse which makes the relaxation time shorter as needed. 10s is used by some NMR users. This is limited to protonated carbons. If time allows, I would say 20s or longer should be better. If quaternary carbon is involved, as I would always say, 60s might be needed.