As seen from the pulse sequence above, the experiment consists of a selective 180° proton pulse p1 with a very narrow bandwidth and low power level (γB₂ ≈ 1 Hz) centered on a particular transition of the ¹³C,H spin system, followed by a hard sampling pulse p2 in the ¹³C channel. You have to set:

td	64 k
sw	200 ppm
o1	middle of the ¹³C NMR spectrum
o2	exact transition frequency of a ¹³C satellite in the ¹H NMR spectrum
p1	180° ¹H decoupler pulse at chosen attenuation; here 0.4 s at 90 dB was used, see Exp. 2.9
p2	45° ¹³C transmitter pulse
d1	2 s
ns	8

Measure a normal ¹H NMR spectrum and a proton-coupled ¹³C spectrum (gated decoupling, see Exp. 4.10) as reference spectra. Load a pulse program for the heteronuclear SPT experiment and adjust the p1 power to γB₂ ≈ 1 Hz, typically in the order of 90 dB attenuation (see Exp. 2.9). Adjust o2 to a frequency 2 Hz above that of the left-most line of the proton doublet at δ_H = 7.5, in order to excite the corresponding ¹³C satellite signal. Measure the SPT spectrum and repeat this for the other satellites of the spin system.

5. Processing

Use standard 1D processing as described in Experiment 3.2.

6. Result

Heteronuclear SPT reference and selective spectra of 3-chloroacrylic acid