Measurement method of
nuclear magnetic resonance spectroscopy used for determining the presence of primary, secondary and tertiary heteronuclei.
Notes: - DEPT is a 1D technique which is used typically for \(\ce{^{13}C}\).
- The DEPT experiment for \(\ce{^{13}C}\) differentiates between \(\ce{CH}\), \(\ce{CH2}\) and \(\ce{CH3}\) groups by variation of the selection angle parameter (the flip angle of the final \(\ce{^{1}H}\) pulse): \(\pu{135\!^{\circ}}\) angle gives all \(\ce{CH}\) and \(\ce{CH3}\) in a phase opposite to \(\ce{CH2}\); \(\pu{90\!^{\circ}}\) angle gives only \(\ce{CH}\) groups, the others being suppressed; \(\pu{45\!^{\circ}}\) angle gives all carbons with attached protons with the same phase.
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 686 (https://doi.org/10.1515/pac-2019-0203)