DEPT Experiment

The DEPT Experiment creates Distortionless Enhancement by Polarization Transfer. This experiment can be used to increase the signal intensities of 13C, or can be used to distinguish quaternary, methine, methylene, and methyl carbons.

1. Collect an optimized 13C spectrum.

2. Type gain='y' gain? --note the value of the gain

3. Type dept to set up the DEPT experiment.

4. Adjust the following parameters:

pw 90° pulse for ¹³C listed at console

tpwr transmitter power listed at console

pp 90° pulse for ¹H ON DECOUPLER CHANNEL listed at console

pplvl pplvl listed at console

j average ¹H-¹³C coupling constant (about 140 Hz)

d1 relaxation delay, approximately 3T₁ - at

nt multiple of 4, best if multiple of 16

satdly to presaturate peak at center of spectrum, type satdly='y'

hs homospoil not recommended, type hs='nn'

5. To increase all ¹³C signal intensities, type mult=0.5

To distinguish protonation states, type mult=0.5,1.0,1.0,1.5

0.5 generates spectrum with only protonated carbons

1.0 generates spectrum with CH carbons, all other carbons suppressed

1.5 generates spectrum with CH and CH₃ carbons pointed up and CH₂ carbons down

0.5,1.0,1.0,1.5 generates spectra for autodept routine

6. Type ga to start the experiment.

7. If you used the DEPT experiment to increase all ¹³C signal intensities, see Data Processing 1D Spectra.

8. When the experiment is finished, type autodept to generate plots of unedited spectra, edited spectra, and automatic spectrum analysis. If some peaks are not automatically analyzed, manually perform the autodept routine:

A. Type wft and phase the spectrum

B. Set spectrum vertical scale (vs) and threshold (click on main menu, display, interactive, more, thresh) so that all peak heights are greater than the threshold.

C. Type fp adept ds(1) vsadj

D. Type vp=0 and then adjust vs

E. Type vs=vs/4 vo=vs ho=0 full dssa

F. Type ppa pll('all') pscale page to plot all spectra .

The results of the experiment are:

Spectrum #1: all carbons

Spectrum #2: CH carbons

Spectrum #3: CH₂ carbons

Spectrum #4: CH₃ carbons