第1楼2005/05/31
Quantitative 13C spectra
Integration of 13C spectra is more complicated than integrating 1H spectra. 13C relaxation times tend to be very long so your spectrum may require using a very long relaxation delay time (d1 or last delay). These relaxation times may also be decreased by adding a relaxation agent such as Cr(acac)3. NOEs between 1Hs and 13C nuclei will also affect your measured intensities so you must use inverse-gated decoupling which involves decoupling 1Hs only during acquisition.
4. For inverse-gated decoupling type dm='nny' on the Varian instruments. On the AF-300 open up the pulse sequence icon(click on far right icon in upper left-hand corner). Open the file called 1 Pulse Dec on Acq.
5. For the most accurate integrals you want to make sure the relaxation delay is very long relative to the longest T1 in your sample. This delay should be at least 2.5xT1 and at least 10 times longer than the acquisition time.
6. The S/N ratio should be at least 35:1 for the best results.