Application of Relaxation Reagents in the 13C-NMR Quantitative Analysis
In 13C-PFT-n.m.r. spectrum, the intensities of different signals become almost equal on adding Cr(acac)3 as a relaxation reagent. An intensity ratio precisely corresponding to the number of the adjacent carbon atoms can be reached only with infinitely high concentrations of Cr(acac)3. By means of a linearized function, it is possible to give an extrapolation to this infinitely high concentration. In this way, a quantitative 13C-n.m.r. analysis can be obtained routinely. The method does not require calibration, the standard deviation amounts to about 10% (rel.).