The editing feature alters the sign of the carbon resonances according to the number of directly attached protons, allowing the identification of carbon multiplicities. Since 1H has a fourfold larger gyromagnetic ratio compared to 13C, the initial population difference for 1H spins (loosely speaking, the difference between the number of spin-up and spin-down nuclei) is approximately four times larger, which translates into higher sensitivity. The sensitivity gain arises because the experiment is started with proton excitation, with the proton magnetisation subsequently being transferred onto carbon. 1D 13C spectra (including DEPT) are only useful for structural assignment if there is intractable peak overlap in the HSQC, which is rare. Note that the DEPT experiment has largely been superseded by the multiplicity-edited HSQC, which provides more information with greater sensitivity and often in less time. A 1D experiment used for enhancing the sensitivity of carbon observation and for editing of 13C spectra.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |