Both the APT (Attached Proton Test) and (DEPT) Distortionless Enhancement by Polarization Transfer are both experiments used for determining the number of protons attached to each carbon in a 13 C spe...Both the APT (Attached Proton Test) and (DEPT) Distortionless Enhancement by Polarization Transfer are both experiments used for determining the number of protons attached to each carbon in a 13 C spectrum. Both experiments yield 13 C NMR spectra where the number of attached protons (the multiplicity) is encoded in the phase of the 13 C NMR signals. This is helpful because the abundance of 1 H is [ greater or lower ] 13 C so the transfer of polarization can increase the sensitivity.
