¹H acquisition can be performed with decoupling of a specific ¹H region. The final will contain all conventional format except chemical shifts of the decoupled region and all couplings arising from the decoupled resonances. Thus, multiplets are simplified, sensitivity and resolution can be greatly improved and coupling constants values and multiplet patterns can be extracted. This approach has been applied in 2D homonuclear experiments.

This is a particular case of homodecoupling.

Easy implementation on AVANCE spectrometers.

 See Tutorial: Band-selective Homodecoupling.

The most standard way to implement a ¹H acquisition period using homodecoupling is:

... 2 d1 d12 pl24:f2 3u cpdngs2:f2 go=2 ph31 hd:f2 ... d12 do:f2 ...

in which:

• go starts data acquisition during an acq period using the acquisition parameters previously defined in eda.
• Band-selective homodecoupling is performed at low power (pl14) from the f2 channel using the hd command. The frequency to be irradiated is set to o2. and the sequence is defined by the cpdprg2 and pcpd2 parameters.
• The number after go (=2) defines the loop to be executed. The number of times this loop is repeated is governed by the number of scans (ns).
• ph31 is the receiver phase specified at the end of pulse program and must be cycled in accordance to all pulses involved in the pulse sequence.
• Band-selective homodecoupling is stopped using the do command.