DEPT (Distortionless Enhancement by Polarization Transfer)

Allow to distinguish signals of quaternary carbon atoms, CH, CH 2 and CH 3 groups.

Experiment DEPT (Distortionless Enhancement by Polarization Transfer) allows to distinguish between signals of quaternary, methine, methylene and methyl carbon atoms in the range of 13 C.

Depending on the multiplicity of the signals may be either positive or negative intensity. The most commonly used kind of experiment is DEPT DEPT135, in which the signals of the methylene carbon atoms - have negative intensity, methine and methyl - positive, and the signals of carbon atoms not directly associated with the protons do not appear. The spectrum exhibited only signals DEPT90 methine carbons and the spectrum DEPT45 quaternary carbons are not shown, and other signals - positive.

Experiment DEPT, usually used in conjunction with experiment 13 C with complete suppression of the spin-spin coupling (13 C { 1 H} experiment). From the analysis of the spectra of 13 C with suppression, DEPT135 and DEPT90 possible to draw conclusions about the multiplicity of all carbon atoms in the molecule.

As a result of polarization transfer to protons on the carbon atoms in the DEPT experiment of the sensitivity of the method is approximately four times greater than that of the standard experimental 13 C to complete suppression, and the experiment APT (Attached Proton Test).

DEPT experiment is less critical to the accuracy of selecting the value of direct constants C-H used to calculate a delay in the pulse sequence than experiment INEPT. This feature is useful in analyzing the structure containing carbon atoms of different natures, CH constants which respectively vary widely.