The DEPT block has been used as alternative of the INEPT block when designing new multidimensional NMR methodologies. It also permits to obtain sensitivity improvements by polarization transfer from the high-sensitive ¹H nuclei to low-sensitive X nuclei as ¹³C and ¹⁵N. In addition, it usually permits to use a faster pulse sequence repetition.

Some enhancement factors for NOE and INEPT schemes with X{¹H} pairs of nuclei:

 

X	11B	13C	15N	29Si	57Fe	103Rh	109Ag	119Sn	183W
NOE	2.56	2.99	-3.94	-1.52	16.48	-16.89	-9.75	-0.41	13.02
DEPT	3.12	3.98	9.87	5.03	30.95	31.77	21.50	2.81	24.04

 
The DEPT block involves the creation of heteronuclear multiple-quantum coherences from ¹H and further conversion to in-phase X magnetization.

Easy implementation on AVANCE spectrometers.

The evolution delay must be optimized to 1/2*¹J_XH. For further details about implementation of 1D INEPT and 1D DEPT experiments in AVANCE spectrometers see, for instance:

• Tutorial: 1D INEPT experiment
• Tutorial: 1D DEPT experiment.

The most standard way to implement the DEPT block in a pulse program is:

... (p3 ph1):f2 d2 (p4 ph2):f2 (p1 ph4) d2 (p0 ph3):f2 (p2 ph5) d2 ...

in which:

p1 and p2 are the 90º and 180º X pulse (in microseconds) applied at a power level pl1 from the f1 channel

p0, p3 and p4 are the variable, 90º and 180º ¹H pulse (in microseconds) applied at a power level pl2 from the f2 channel

d2 must be optimized to 1/2*¹J_XH

All phases are specified at the end of pulse program.

The same blocks using several modified commands can be used in inverse detected experiments in which the ¹H and X channels are exchanged. Thus, for ¹H-¹³C inverse detected experiments we have:

... (p1 ph1) d2 (p2 ph2) (p3 ph4):f2 d2 (p0 ph3) (p4 ph5):f2 d2 ...

The DEPT block can be incorporated in related multidimensional experiments as founs usually for the INEPT block: